Details of a Researcher - UMEZU, Mitsuo

写真a

UMEZU, Mitsuo

Scopus Paper Info

Paper Count: 289 Citation Count: 4761 h-index: 27

Click to view the Scopus page. The data was downloaded from Scopus API in December 20, 2024, via http://api.elsevier.com and http://www.scopus.com .

Affiliation

Faculty of Science and Engineering

Job title

Professor Emeritus

Degree

工学博士 ( 早稲田大学 )
Doctor of Engineering ( Waseda Unversity )
Doctor of Medical Science ( Tokyo Women's Medical University )

Homepage URL

http://www.umezu.mech.waseda.ac.jp/

Professional Memberships

　

　

　

ライフサポート学会
　

　

　

日本機械学会
　

　

　

Japanese Society for Artificial Organs
　

　

　

International Society for Artificial Organs

Research Areas

Mechanics and mechatronics / Biomaterials / Biomedical engineering

Research Interests

医用機械工学、人工臓器工学

Awards

2011 JBSE GRAPHICS OF THE YEAR AWARD

2012.03
Excellent poster award(ISOMRM ,Taiwan)

2010.11
日本バーチャルリアリティ学会論文賞

2010.09
Young Investigator Award 1st Praze:11th international congress of the IUPESM,T Yagi, S Wakasa, N Tokunaga, Y Akimoto, M Umezu

2009.09
Outstanding paper award: The 13th International Conference Biomedical Engineering, K Iwasaki, S Tsubouchi, Y Hama, m Umezu: Successful reproduction of In-Vitro fracture of an endovascular stent in superficial femoral artery utilizing a novel multi-loading

2008.12
Outstanding paper award:K Sakaguchi, T shimizu, k Iwasaki, m yamato, M Umezu, T Okano: Fabrication of three dimensional tissues with perfused microchannels, The 13th International Conference Biomedical Engineering, The 13th International Conference Biomed

2008.12
Outstanding paper award: The 13th International Conference Biomedical Engineering, K Iwasaki, S Tsubouchi, Y Hama, m Umezu: Successful reproduction of In-Vitro fracture of an endovascular stent in superficial femoral artery utilizing a novel multi-loading durability test system, The 13th International Conference Biomedical Engineering, 2008.12,(Singapore)

2008.12
Outstanding paper award:K Sakaguchi, T shimizu, k Iwasaki, m yamato, M Umezu, T Okano: Fabrication of three dimensional tissues with perfused microchannels, The 13th International Conference Biomedical Engineering, The 13th International Conference Biomedical Engineering program and abstracts, Biomedical Engineering Society Singapore, pp192, 2008.12,(Singapore

2008.12
Best Poster Award gold prize田中智美、山家弘雄、岡本吉弘、小橋宏行、岩崎清隆、梅津光生、寺田友昭、板倉徹第24回日本脳神経血管内治療学会総会、プログラム抄録vol.2,no.4、ｐｐ262、Journal of Neuroendovascular Therapy、2008.11（ポスター発表）

2008.11
Best Poster Award bronze prize北谷優太郎、高尾洋之、銭逸、福井弘一、石橋敏寛、村山雄一、梅津光生：血流シミュレーション技術を用いた破裂脳動脈瘤の形状的要素の検討、第24回日本脳神経血管内治療学会総会、第24回日本脳神経血管内治療学会総会プログラム抄録vol.2,no.4、ｐｐ295、Journal of Neuroendovascular Therapy、2008.11（ポスター発表）

2008
日本脳神経血管内治療学会ポスター銀賞：田中智美、山家弘雄、岡本吉弘、矢田裕紀、小橋宏行、岩﨑清隆、梅津光生、寺田友昭、板倉徹

2007.11
Excellent cooperation on Educational Invited Lecture 2,第12回日本冠動脈外科学会,2007.7Mitsuo Umezu:JACAS2007,

2007.07
“Young Scientist Award”12th International Symposium on Flow Visualization,Germany,T Yagi,D Ishikawa,H Sudo,T Akutsu,W Yang,K Iwasaki,M Umezu,Real- Time planar spectral analysis of instantaneous high-frequency stress on blood cells downstream of an artific

2006.09
“Young Scientist Award”12th International Symposium on Flow Visualization,Germany,T Yagi,D Ishikawa,H Sudo,T Akutsu,W Yang,K Iwasaki,M Umezu,Real- Time planar spectral analysis of instantaneous high-frequency stress on blood cells downstream of an artificial heart valve,

2006.09
Outstanding Paper Award,K Iwasaki,S Ozaki,T Kawai,S Yamaguchi,M Eto,Y Ohba,Y Ohzeki,M Umezu,12th International Conference on Biomedical Engineering

2005.12
Technical Award (Japanese Society for Artificial Organs,2005)

2005.11
生体医工学シンポジウムベストリサーチアワード，植松美幸，白石泰之，関根一光，山家智之，西條芳文，安藤隼人，朴栄光，武田朴，岩﨑清隆，梅津光生：左心室形成術における切除線決定のための診断法の開発，2005，9月

2005.09
Hpnorable Award

2001
人工臓器貢献賞（チェコ）

1999

▼display all

Papers

異なる機械式弁を組み込んだ拍動型補助人工心臓のin-vitro溶血性能比較評価,

松橋祐輝, 岩崎清隆, 高橋東, 平田麻由紀, 梅津光生

第42回人工心臓と補助循環懇話会学術集会プログラム・抄録集 137 2114.03
Investigation of adverse events associated with an off-label use of arterial stents and CE-marked iliac vein stents in the iliac vein: insights into developing a better iliac vein stent

Shida, Takuya, Umezu, Mitsuo, Umezu, Mitsuo, Iwasaki, Kiyotaka, Iwasaki, Kiyotaka

Journal of Artificial Organs 1 - 7 2018.02

　View Summary

© 2018 The Japanese Society for Artificial Organs We analyzed the adverse events associated with an off-label use of arterial stents and CE-marked iliac vein stents for the treatment of iliac venous thromboembolism and investigated their relationships with the anatomical features of the iliac vein, to gain insights into the development of a better iliac vein stent. Reports of adverse events following the use of stents in the iliac vein were retrieved from the Manufacturer and User Facility Device Experience (MAUDE) database that contain suspected device-associated complications reported to the Food and Drug Administration. Data from 2006 to 2016 were investigated. The literature analysis was also conducted using PubMed, Cochrane Library, EMBASE, and Web of Science focusing on English articles published up to 4 October 2016. The analysis of 88 adverse events from the MAUDE database and 182 articles from the literature revealed that a higher number of adverse events had been reported following the use of arterial stents in the iliac vein compared to CE-marked iliac vein stents. While stent migration and shortening were reported only for the arterial stents, stent fracture and compression occurred regardless of the stent type, even though a vein does not pulsate. A study of the anatomical features of the iliac vein implies that bending, compression, and kink loads are applied to the iliac vein stents in vivo. For designing, developing, and pre-clinical testing of stents intended for use in the iliac vein, the above mechanical load environments induced by the anatomical features should be considered.

DOI

Scopus

10

Citation

(Scopus)
Real-time visualization of thrombus formation at the interface between connectors and tubes in medical devices by using optical coherence tomography

Yuki Matsuhashi, Kei Sameshima, Yoshiki Yamamoto, Mitsuo Umezu, Kiyotaka Iwasaki

PLOS ONE 12 ( 12 ) 2017.12 [Refereed]

　View Summary

Background
Blood-contacting devices have contributed to improving the treatment of patients. However, thrombus formation at the interface between a connector and tube is still a potential source of thrombus-related complications that induce stroke or myocardial infarction. We aimed to develop a non-blood-contacting real-time method for visualizing thrombus formation, and to experimentally investigate the time-dependent phenomenon of thrombus formation at the interface between a connector and a tube in a medical device.
Methods and findings
An optical coherence tomography device with a center wavelength of 1330 nm was used to visualize thrombus formation during porcine blood circulation for 50 min in a closed 50-mL circulation system isolated from ambient air. The thrombus formation sites at the interface between a tube and connector were visualized. The area of the thrombus formation at the interface between the inlet of the connector and the tube was found to be 0.012 +/- 0.011 mm 2. Conversely, at the interface between the outlet of the connector and the tube, the area was found to be 0.637 +/- 0.306 mm(2). Thus, significantly larger amounts of thrombus were formed at the outlet interface (p < 0.01). The thrombus formation area at the outlet interface increased over time. Conversely, the area of thrombus formation showed repeated increasing and decreasing behavior at the inlet interface. Flow visualization with particle image velocimetry showed the presence of a flow separated area in the minimal flow phase at the inlet interface and a large recirculating slow flow region at the outlet interface in the minimal flow phase. These data suggested that the recirculating stagnant flow region contributed to thrombus growth.
Conclusions
The method presented here was effective in quantitatively assessing time-dependent phenomena of thrombus formation at the connector-tube interface. The method may contribute to the assessment of thrombogenicity of a novel design of connector.

DOI PubMed

Scopus

10

Citation

(Scopus)
Investigation of the influence of fluid dynamics on thrombus growth at the interface between a connector and tube

Yuki Matsuhashi, Kei Sameshima, Yoshiki Yamamoto, Mitsuo Umezu, Kiyotaka Iwasaki

JOURNAL OF ARTIFICIAL ORGANS 20 ( 4 ) 293 - 302 2017.12 [Refereed]

　View Summary

Thrombus formation at the interface between connectors and tubes is a potential risk factor for complications. We investigated time-dependent relationships between formation of thrombus and hemodynamic factors at the interface between connectors and tubes using optical coherence tomography (OCT) under pulsatile flow. A swept-source OCT with the center wavelength of 1330 nm was employed. The sequential process of thrombus formation at the interface of connectors and tubes in the inlet and outlet was investigated. Connectors with and without tapers were tested using identical 50-ml air-contactless circuits. Fresh human blood from healthy volunteers was circulated under pulsatile flow. Thrombus initially formed at the interface between the connector tip and the tube. Geometries of thrombus growth were different between the 2 connectors, and between the inlet and the outlet. Growth of thrombus was observed at the interface between the connectors and tubes over time in 60 min circulation, except at the outlet part of connector without tapers. At the connector without tapers outlet, thrombus propagation length from the connector edge toward the flow downstream was comparable at 10 and 60 min (0.55 +/- 0.35 vs. 0.51 +/- 0.32 mm, p = 0.83). Analysis using particle image velocimetry showed the presence of a flow reattachment point 1.5 mm downstream from the connector edge. These results suggest that the flow reattachment point inhibits downstream thrombus growth. We quantitatively demonstrated sequential thrombus process at the interface between the connectors and tubes under pulsatile flow of human blood using OCT.

DOI

Scopus

9

Citation

(Scopus)
A three-dimensional strain measurement method in elastic transparent materials using tomographic particle image velocimetry

Azuma Takahashi, Sara Suzuki, Yusuke Aoyama, Mitsuo Umezu, Kiyotaka Iwasaki

PLOS ONE 12 ( 9 ) 2017.09 [Refereed]

　View Summary

Background
The mechanical interaction between blood vessels and medical devices can induce strains in these vessels. Measuring and understanding these strains is necessary to identify the causes of vascular complications. This study develops a method to measure the threedimensional (3D) distribution of strain using tomographic particle image velocimetry (Tomo-PIV) and compares the measurement accuracy with the gauge strain in tensile tests.
Methods and findings
The test system for measuring 3D strain distribution consists of two cameras, a laser, a universal testing machine, an acrylic chamber with a glycerol water solution for adjusting the refractive index with the silicone, and dumbbell-shaped specimens mixed with fluorescent tracer particles. 3D images of the particles were reconstructed from 2D images using a multiplicative algebraic reconstruction technique (MART) and motion tracking enhancement. Distributions of the 3D displacements were calculated using a digital volume correlation. To evaluate the accuracy of the measurement method in terms of particle density and interrogation voxel size, the gauge strain and one of the two cameras for Tomo-PIV were used as a video-extensometer in the tensile test. The results show that the optimal particle density and interrogation voxel size are 0.014 particles per pixel and 40 x 40 x 40 voxels with a 75% overlap. The maximum measurement error was maintained at less than 2.5% in the 4-mmwide region of the specimen.
Conclusions
We successfully developed a method to experimentally measure 3D strain distribution in an elastic silicone material using Tomo-PIV and fluorescent particles. To the best of our knowledge, this is the first report that applies Tomo-PIV to investigate 3D strain measurements in elastic materials with large deformation and validates the measurement accuracy.

DOI PubMed

Scopus

3

Citation

(Scopus)
Improvement and modulation of mechanical properties of hydrogel from ventricular extracellular matrix and its compatibility for cell culture

Fujita Kyohei, Feng Zhonggang, Kosawada Tadashi, Sato Daisuke, Nakamura Takao, Shiraishi Yasuyuki, Umezu Mitsuo

Transactions of Japanese Society for Medical and Biological Engineering 55 ( 5 ) 430 - 430 2017

　View Summary

The mechanical properties of a scaffold is one of the critical cues for differentiating stem cells. Although hydrogels reconstituted from cardiac ECM have been utilized as a scaffold to induce cardiac differentiation, how to obtain the appropriate mechanical properties of the hydrogel for cardiac differentiation has not been investigated. We modulated the mechanical properties of ventricular ECM hydrogels (vECM gels) using N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC). The mechanical properties of vECM gels were investigated by means of compression test and analyzed by a non-linear viscoelastic model, which consists of two non-linear springs, the first determines the reversible elasticity and the second for the viscous dissipation. The first elastic modulus K1 in 12.5 mg/ml-vECM gels can be enhanced from 129.5 Pa to 3868.0 Pa by EDAC treatment as well as the second modulus K2 from 1956.3 Pa to 5915.9 Pa. The compatibility of the gels for cell culture was also investigated.

DOI CiNii
Six-case reports in clinical trials on a new surgical navigation system for thoracic and thoracoabdominal aortic aneurysm

Uematsu Miyuki, Aomi Shigeyuki, Yamazaki Kenji, Iwasaki Kiyotaka, Umezu Mitsuo, Nakaoka Ryusuke, Haishima Yuji, Suzuki Takashi, Muragaki Yoshihiro, Iseki Hiroshi

Transactions of Japanese Society for Medical and Biological Engineering 55 ( 5 ) 434 - 434 2017

　View Summary

We have been developing a surgical navigation system to support a surgeon to identify the anatomical orientation. Its first prototype was designed in 2004 and clinically tested in 2006. During this decade, we have utilized it in one hundred clinical cases. Learned through trial and error, it was found that this system needed to improve the usability and the reliability in registration process to show valuable information for surgery. Our improved system was approved to use for clinical pre-trial from Hospital Ethics Committee of Tokyo Women's Medical University (160402), and it was utilized for six cases from June 2016 to January 2017. The new system worked suitably compared with the former one. As for spending time on the new system, it took 9.8±1.7 minutes before thoracotomy and 6.4±1.5 minutes after adhesiolysis. Target arteries were determined smoothly in all cases. We hope that widespread use of the system would be promoted.

DOI CiNii
Cellular and tissue mechanics in collagen gels

Feng Zhonggang, Kosawada Tadashi, Nakamura Takao, Sato Daisuke, Umezu Mitsuo

Transactions of Japanese Society for Medical and Biological Engineering 55 ( 3 ) 200 - 200 2017

　View Summary

Collagen gels will contract as mesenchymal cells populated within. As 3D tissue models, cell-collagen gels attract extensive attention in studies related to wound healing, cellular fate processes, and regenerative medicine. In this study, we investigated the mechanical fundamentals of the cell and the gel from the perspective of collagen fibril and its network. We found an intrinsic biphasic relationship between cellular traction force and matrix elasticity during the gel contraction and that the network characteristics determined the mechanical behavior of the gels.

DOI CiNii
細胞シート技術を用いたヒト立体心筋組織構築

坂口勝久, 戸部友輔, 中園一紀, 清水達也, 梅津光生

生体医工学 55 ( 3 ) 202 - 202 2017

　View Summary

単離された心筋細胞から拍動する立体的な心筋組織への構築は新たな再生医療や薬剤スクリーニングへの応用として注目されている。本研究では、温度に応答して細胞脱着可能な培養皿を用いて細胞をシート状に形成し、その細胞シートを積層化することによって心筋組織の構築・移植を試みている。現在、細胞シートは角膜、心臓、食道等の損傷に対する細胞治療として臨床応用まで到達している。細胞シート治療を更なる効果向上を目指すため、短時間で多層(5～15層)に積層し、移植後の血管新生を促進させる方法を考案した。具体的な手法として、極めて微量の生体接着剤（フィブリン）を塗布し、さらに力学的な負荷を与えて、積層時間を数分間に大幅加速する手法である。これにより、従来手法では細胞シートを積層するのに約１時間を要していたところを５分以内の積層が可能となった。積層時間の大幅な短縮により再生立体組織を移植可能となるため簡便かつ安定的に組織を提供でき、また細胞同士の接着が脆弱で積層できなかった細胞種（肝細胞、内皮細胞）が積層可能で今までに無かった細胞種の組み合わせによる新しい細胞シート治療が提供できる。本発表では、短時間に組織構築する手法、構築した心筋組織の移植結果を報告する。

CiNii
Reduction in incomplete stent apposition area caused by jailed struts after single stenting at left main bifurcation lesions: micro-CT analysis using a three-dimensional elastic bifurcated coronary artery model

Yutaka Hikichi, Mitsuo Umezu, Koichi Node, Kiyotaka Iwasaki

Cardiovascular Intervention and Therapeutics 32 ( 1 ) 12 - 17 2017.01

　View Summary

Stent struts protruding into ostial side branch called “jailed strut” at bifurcation lesions is a likely cause of thrombus formation. We aimed to investigate the influences of multiple kissing balloon inflation (KBI) for stent expansion, and stent platform design, respectively, on the reduction of incomplete stent apposition area (ISA area) caused by jailed struts at a side-branch ostium, using a three-dimensional elastic left main (LM) bifurcated coronary artery model. The referenced LM bifurcation angle data of 209 patients were stratified by tertiles focusing on the angle between the LM trunk (LMT) and left anterior descending artery (LAD). A bifurcation model was fabricated with angles of 129°, 122.2°, and 76.4° for LMT–LAD, LMT–left circumflex (LCx), and LAD–LCx, respectively, and with diameters of 5, 3.75, and 3.5 mm for LMT, LAD, and LCx, respectively
these diameters fulfill Murray’s law. A 75 % stenosis was included along the LMT. One-time and three-time KBIs were conducted using two-link Nobori and three-link Xience Xpedition (n = 6 each). The ISA area was quantified using micro-CT. Three-time KBI was effective in reducing the ISA area compared with one-time KBI for both the Nobori (p = 0.05) and Xience Xpedition (p = 0.07). The ISA area was smaller in the Nobori than in the Xience Xpedition, both in one-time and three-time KBI (one-time KBI: p = 0.003
three-time KBI: p = 0.001). Our findings of this study on reducing the ISA area by focusing on an interventional technique and stent design may help to improve coronary bifurcation intervention for a possibly better long-term clinical outcome.

DOI PubMed

Scopus

15

Citation

(Scopus)
Regulatory science of new technology: tendency of medical professionals' interests on silicone breast implants

Tomomichi Nakazaki, Koji Ikeda, Kiyotaka Iwasaki, Mitsuo Umezu

JOURNAL OF ARTIFICIAL ORGANS 19 ( 3 ) 283 - 288 2016.09 [Refereed]

　View Summary

New technology related to artificial organs is most attractive for worldwide researchers. We believe they must contribute for the future patients against untreatable diseases. Regulatory science is a new science to establish 'social acceptance' of new technology into the clinical market as soon as possible. In the history of silicone breast implants, we could recognize risks many times; however, we missed such chances to prevent a subsequent crisis. We analyzed the trend of published literature related to silicone breast implants to review the medical professionals' interests on such risks. This trend showed, despite issues of a social acceptance of silicone breast implants in a few countries, other countries' medical professionals had no interest. Our hypothesis is 'medical professionals face the government and do not have contributed to re-establish the social acceptance of new technologies for patients'. Any technology does not have the complete evidence of safety, efficacy and quality, despite regulatory authorities' review and approval with clinical evidences. medical professionals need to conduct subsequently the epidemiological study, to take a meta-analysis periodically and to create/update the guidance for their patients under their professional ethics after the marketing of new technologies. We need to take seriously the 'lesson learned' from the history of silicone breast implants for all kind of new technologies existed in the present.

DOI

Scopus

2

Citation

(Scopus)
In vivo vascularization of cell sheets provided better long-term tissue survival than injection of cell suspension.

Ryohei Takeuchi, Yosuke Kuruma, Hidekazu Sekine, Izumi Dobashi, Masayuki Yamato, Mitsuo Umezu, Tatsuya Shimizu, Teruo Okano

Journal of tissue engineering and regenerative medicine 10 ( 8 ) 700 - 10 2016.08 [Refereed] [International journal]

　View Summary

Cell sheets have shown a remarkable ability for repairing damaged myocardium in clinical and preclinical studies. Although they demonstrate a high degree of viability as engrafted cells in vivo, the reason behind their survivability is unclear. In this study, the survival and vascularization of rat cardiac cell sheets transplanted in the subcutaneous tissue of athymic rats were investigated temporally. The cell sheets showed significantly higher survival than cell suspensions for up to 12 months, using an in vivo bioluminescence imaging system to detect luciferase-positive transplanted cells. Terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assay also showed a smaller number of apoptotic cells in the cell sheets than in the cell suspensions at 1 day. Rapid vascular formation and maturation were observed inside the cell sheets using an in vivo imaging system. Leaky vessels appeared at 6 h, red blood cells flowing through functional vessels appeared at 12 h, and morphologically matured vessels appeared at 7 days. In addition, immunostaining of cell sheets with nerve/glial antigen-2 (NG2) showed that vessel maturity increased over time. Interestingly, these results correlated with the dynamics of cell sheet mRNA expression. Genes related to endothelial cells (ECs) proliferation, migration and vessel sprouting were highly expressed within 1 day, and genes related to pericyte recruitment and vessel maturation were highly expressed at 3 days or later. This suggested that the cell sheets could secrete appropriate angiogenic factors in a timely way after transplantation, and this ability might be a key reason for their high survival. Copyright © 2014 John Wiley & Sons, Ltd.

DOI PubMed

Scopus

35

Citation

(Scopus)
In vivo vascularization of cell sheets provided better long-term tissue survival than injection of cell suspension.

Ryohei Takeuchi, Yosuke Kuruma, Hidekazu Sekine, Izumi Dobashi, Masayuki Yamato, Mitsuo Umezu, Tatsuya Shimizu, Teruo Okano

Journal of tissue engineering and regenerative medicine 10 ( 8 ) 700 - 10 2016.08 [Refereed] [International journal]

　View Summary

Cell sheets have shown a remarkable ability for repairing damaged myocardium in clinical and preclinical studies. Although they demonstrate a high degree of viability as engrafted cells in vivo, the reason behind their survivability is unclear. In this study, the survival and vascularization of rat cardiac cell sheets transplanted in the subcutaneous tissue of athymic rats were investigated temporally. The cell sheets showed significantly higher survival than cell suspensions for up to 12 months, using an in vivo bioluminescence imaging system to detect luciferase-positive transplanted cells. Terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assay also showed a smaller number of apoptotic cells in the cell sheets than in the cell suspensions at 1 day. Rapid vascular formation and maturation were observed inside the cell sheets using an in vivo imaging system. Leaky vessels appeared at 6 h, red blood cells flowing through functional vessels appeared at 12 h, and morphologically matured vessels appeared at 7 days. In addition, immunostaining of cell sheets with nerve/glial antigen-2 (NG2) showed that vessel maturity increased over time. Interestingly, these results correlated with the dynamics of cell sheet mRNA expression. Genes related to endothelial cells (ECs) proliferation, migration and vessel sprouting were highly expressed within 1 day, and genes related to pericyte recruitment and vessel maturation were highly expressed at 3 days or later. This suggested that the cell sheets could secrete appropriate angiogenic factors in a timely way after transplantation, and this ability might be a key reason for their high survival. Copyright © 2014 John Wiley & Sons, Ltd.

DOI PubMed

Scopus

35

Citation

(Scopus)
Time Series Analysis of the Effectiveness and Safety of Capsule Endoscopy between the Premarketing and Postmarketing Settings: A Meta-Analysis

Kazuo Iijima, Mitsuo Umezu, Kiyotaka Iwasaki

PLOS ONE 11 ( 6 ) 2016.06 [Refereed]

　View Summary

Background
Clinical studies for assessing the effectiveness and safety in a premarketing setting are conducted under time and cost constraints. In recent years, postmarketing data analysis has been given more attention. However, to our knowledge, no studies have compared the effectiveness and the safety between the pre- and postmarketing settings. In this study, we aimed to investigate the importance of the postmarketing data analysis using clinical data.
Methods and Findings
Studies on capsule endoscopy with rich clinical data in both pre- and postmarketing settings were selected for the analysis. For effectiveness, clinical studies published before October 10, 2015 comparing capsule endoscopy and conventional flexible endoscopy measuring the detection ratio of obscure gastrointestinal bleeding were selected (premarketing: 4 studies and postmarketing: 8 studies) from PubMed (MEDLINE), Cochrane Library, EMBASE and Web of Science. Among the 12 studies, 5 were blinded and 7 were non-blinded. A time series meta-analysis was conducted. Effectiveness (odds ratio) decreased in the postmarketing setting (premarketing: 5.19 [95% confidence interval: 3.07-8.76] vs. postmarketing: 1.48 [0.81-2.69]). The change in odds ratio was caused by the increase in the detection ratio with flexible endoscopy as the control group. The efficacy of capsule endoscopy did not change between pre- and postmarketing settings. Heterogeneity (I-2) increased in the postmarketing setting because of one study. For safety, in terms of endoscope retention in the body, data from the approval summary and adverse event reports were analyzed. The incidence of retention decreased in the postmarketing setting (premarketing: 0.75% vs postmarketing: 0.095%). The introduction of the new patency capsule for checking the patency of the digestive tract might contribute to the decrease.
Conclusions
Effectiveness and safety could change in the postmarketing setting. Therefore, time series meta-analyses could be useful to continuously monitor the effectiveness of medical device in clinical practices.

DOI

Scopus

4

Citation

(Scopus)
The development of the cell culture system able to change the elasticity of control substrate

Miura Hisashi, Yanagihashi Takayasu, Feng Zhonggang, Kosawada Tadashi, Sato Daisuke, Nakamura Takao, Umezu Mitsuo

Transactions of Japanese Society for Medical and Biological Engineering 54 ( 27 ) S160 - S160 2016

　View Summary

The effects of mechanical properties of the culture substrate on the cellular behavior are intensively investigated. However, most of the studies adjusted the elastic modulus of culture substrates by changing the substrate component concentration. In this study, we take the advantage of the nonlinear mechanical properties of porcine amniotic membrane to realize the sole adjustment of substrate elastic modulus by stretching the membrane at different stresses in a lab-made device. Fibroblasts were able to attach and proliferate nearly to confluence on the membrane (~500 cells/mm2 ) under low stress (elastic modulus smaller than 30.0 kPa); whereas, the cells failed to attach on the membrane under high stress (elastic modulus ~ 6.0 MPa). It implicates that the dynamic characteristics of the amniotic membrane related with the device structure may also impact the cellular behavior because the elastic modulus of conventional culture dishes (~GPa) is much greater than 6.0 MPa.

DOI CiNii
Fabrication of vascularized human cardiac tissue by cell sheet engineering

Sakaguchi Katsuhisa, Shimizu Tatsuya, Matsuura Katsuhisa, Yamato Masayuki, Umezu Mitsuo, Okano Teruo

Transactions of Japanese Society for Medical and Biological Engineering 54 ( 27 ) S167 - S167 2016

CiNii
Analysis of Medical Device Recalls Owing to Output Information from Software

KITAWAKI Ryota, UMEZU Mitsuo, IWASAKI Kiyotaka, KASANUKI Hiroshi

Regulatory Science of Medical Products 6 ( 3 ) 281 - 293 2016

　View Summary

Because software as a medical device (SaMD) does not come into direct contact with patients, it does not pose such direct harm as that caused by conventional hardware medical devices (non-SaMD) ; however, SaMD does present indirect harm. Using US recall data, the objective of this study was to investigate indirect harm caused by software medical devices including both SaMD and non-SaMD. We collected recall data in which the cause was determined by the US Food and Drug Administration to be software design, and we determined whether the product in each recall was SaMD or not (non-SaMD). We also classified the failure mode of each recall into four groups : physical (Group 1) ; information-related (Group 2), data-related (Group 3) ; and other (Group 4). We identified 6,393 recalls for 2009-2014, and 712 software-caused recalls. Of those, the leading failure mode was Group 2 that can lead to indirect harm and accounted for 408 (57%), followed by Group 1 that can lead to direct harm and accounted for 122 (17%). Of 408 Group 2 recalls, 387 (95%) were recall class Ⅱ and 6 (1%) were recall class Ⅰ. Of the 6, 4 were for non-SaMD and 2 were for SaMD. The findings revealed by this study indicate the importance of the further understanding of safety of information presentation functionality and the necessity of further discussion of safety measures.

DOI CiNii
Systematic Analysis of the Incidence of Coronary Stent Fracture and Adverse Events in Japan

MATSUI Yutaka, UMEZU Mitsuo, KASANUKI Hiroshi, IWASAKI Kiyotaka

Regulatory Science of Medical Products 6 ( 1 ) 1 - 10 2016

　View Summary

Coronary stent fracture (SF) is recognized as a risk of restenosis or stent thrombosis. However, the actual incidence is unclear in real world clinical settings in Japan. This study aims to estimate the incidence of SF in Japan by surveying peer-reviewed journals, and to elucidate the actual situation of adverse event reports. We conducted literature analysis regarding the incidence of SF using PubMed and ICHUSHI on April 1 2014. For PubMed, the term "stent fracture" was used. For ICHUSHI, "coronary artery" (in Japanese), "stent" (in Japanese), "fracture" (in English), "fracture" (in Japanese), and "damage" (in Japanese) were used. PubMed search initially yielded 895 papers. Of these, 792 studies had been conducted in countries outside of Japan, 45 studies were related to non-coronary artery, 17 studies did not deal with incidences of SF, and 11 studies targeted duplicated cases during the same implantation period. After these studies were excluded, we analyzed 30 remaining papers comprising 14 observational studies and 16 case reports. There were 643 SF cases in the scientific papers and 105 SF cases in the adverse event reports. Through the 14 observational studies, the SF incidence was estimated as 5.4% (595/10,927 lesions). We found a significant difference in SF incidences between the paper and adverse event report (6.1-hold). These data indicated that the adverse event report showed a partial picture of the real situation.

DOI CiNii
Improvement And Modulation Of Mechanical Properties Of Hydrogel From Ventricular Extracellular Matrix By Carbodiimide Crosslinker

Fujita, K, Feng, Z, Kosawada, T, Sato, D, Nakamura, T, Shiraishi, Y, Umezu, M

TISSUE ENGINEERING PART A 22 S139 - S139 2016 [Refereed]
2E15 Patho-engineering analysis of human cerebral aneurysms : Study on the relationship of foam cell distribution and wall properties

SUTO Kenta, YAGI Takanobu, SUGIURA Takuma, TOBE Yasutaka, KAWAMURA Koichi, UMEZU Mituo, HAYASHI Masafumi, YOSHIDA Hirotaka, NISHITANI Kazutoshi, OKADA Yoshifumi, KITAHARA Sigemi

2016 ( 28 ) "2E15 - 1"-"2E15-4" 2016.01

　View Summary

Foam cells are caused by excessive infiltration of lipid into the artery wall. In the current cerebral aneurysm study the presence of lipids has been shown in the aneurysm wall. However association of foam cells in the aneurysm wall has not been studied. This research 11 aneurysms foam cells accumulation whether in the aneurysm wall and characterized the distribution of foam cells. Tissues were collected from 9 patients after microsurgical clipping of the aneurysm neck. Harvested tissue were than fixed in 4% paraformaldehyde, embedded in paraffin, sliced in semi serial sections of 2 μm thickness, and stained with hematoxylin-eosin(HE) method. The sections were observed after HE staining. Foam cells were found in 4/11 unruptured cerebral aneurysms. Foam cells were different integrated distribution by location. These results suggested that accumulation of foam cells depends on the patients medical history and the blood components.

CiNii
2E14 Patho-engineering analysis of human unruptured cerebral aneurysms : Study of the tissue healing mechanisms by mural cell densities

SUGIURA Takuma, YAGI Takanobu, TOBE Yasutaka, SUTO Kenta, KAWAMURA Koichi, Umezu Mituo, HAYASHI Masafumi, YOSHIDA Hirotaka, NISHITANI Kazutoshi, OKADA Yoshifumi, KITAHARA Shigemi

2016 ( 28 ) "2E14 - 1"-"2E14-4" 2016.01

　View Summary

This research investigated mural cell densities in different wall thickness of five human unruptured cerebral aneurysms to evaluate the tissue healing ability of aneurysmal wall. Five aneurysms were dissected after craniotomy with markings to confirm the orientation of specimens. Harvested tissue were than fixed in 4% paraformaldehyde, embedded in paraffin, sliced in semi serial sections of 3 μm thickness, and stained with hematoxylin-eosin (HE) method. To investigate mural cell densities, wall thickness was measured, and the aneurysmal wall was sectioned into 100 μm increments from histological analysis. All sections were divided into two parts of inside and outside regions from the center of the wall, and inspection areas were focused on the inside region. The characteristics of mural cell densities were classified into three types. First type was that mural cell densities in under 100 μm regions was higher than in 100-200 μm regions, which were observed in case 1 and 4-1. Second type was that the mural cell densities increased in 100-300 μm wall regions, whereas in 300-500 μm regions, the mural cell densities decreased, which were observed in case 2 and 3. Third type was the mural cell densities increased as wall thickness increased, which were observed in case 4-2. These results suggested that the tissue healing ability was different depending on wall thickness and each case.

CiNii
Bio-inspired smart hydrogel with temperature-dependent properties and enhanced cell attachment

Young-Jin Kim, Misa Tachibana, Mitsuo Umezu, Yukiko T. Matsunaga

Journal of Materials Chemistry B 4 ( 9 ) 1740 - 1746 2016

　View Summary

Stimuli-responsive smart hydrogels have been exploited for various applications, including as biomaterials with environment-dependent changes in hydrophobicity, stiffness or volume. In this study, we report the functionalisation of a temperature-responsive poly(N-isopropylacryamide) (PNIPAAm) smart hydrogel with catechol groups to enhance its stiffness and cell attachment. To introduce biomimetic adhesive catechol group, which is derived from mussel feet, a photo-crosslinkable 3-hydroxytyramine hydrochloride-derived dopamine methacrylamide (DMA) monomer was synthesised. Then, temperature-responsive smart copolymer hydrogels were successfully fabricated by photo-polymerisation of the DMA with N-isopropylacryamide (NIPAAm). The fabricated smart hydrogels demonstrated temperature-dependent properties, and the DMA affected the swelling behaviour and compressive mechanical strength. In vitro cell culture experiments showed that the catechol groups in the smart hydrogels promoted cell attachment and spreading. These smart hydrogels will be useful as biomaterials as tissue scaffolds with controllable properties.

DOI

Scopus

33

Citation

(Scopus)
2F35 Investigation of strain measurement method in elastic blood vessel model using tomographic particle image velocimetry

TAKAHASHI Azuma, MATSUHASHI Yuki, SUZUKI Sara, AOYAMA Yusuke, UMEZU Mitsuo, IWASAKI Kiyotaka

2016 ( 28 ) "2F35 - 1"-"2F35-5" 2016.01

　View Summary

Transcatheter aortic valve replacement (TAVI) is a less invasive therapy and the number of operations is increasing. In some operations of TAVI, valve annulus rupture and failure were happened. Strain measurement method in the blood vessel has not been established and there is no way to evaluate the strain distribution experimentally. It is difficult to measure large deformation of the blood vessel using conventional digital volume correlation with computed tomography. This study presents a new strain measurement method of an elastic blood vessel model using the displacement distribution measured by tomographic particle image velocimetry. Tracer particles were distributed in the blood vessel model and displacement distribution was measured by tracking the particles. The displacement measuring accuracy affected by the amount of displacement and spatial resolutions was assessed. The strain yielded in the blood vessel model, when it was 10% expanded, was measured in the optimal condition determined by the accuracy measurement. In this study, the optimal displacement spatial resolutions and displacement condition were 64 X 64 X 64 voxel^3 and 90-150 μm respectively. This experimental investigation revealed that the higher strain was yielded in the inner wall of the blood vessel model and the strain becomes lower toward the outer wall.

CiNii
2F13 Development of a registration method using points of skeleton for navigation in blood vessel prosthesis replacement and error assessment using clinical data

TAKAHASHI Yasuhiro, UEMATSU Miyuki, AOMI Shigeyuki, IIMURA Hiroshi, NAKAOKA Ryusuke, NIIMI Shingo, SUZUKI Takashi, MURAGAKI Yoshihiro, ISEKI Hiroshi, UMEZU Mitsuo, IWASAKI Kiyotaka

2016 ( 28 ) "2F13 - 1"-"2F13-5" 2016.01

　View Summary

We have developed a navigation system for the blood vessel prosthesis replacement of aortic aneurysms, and have used it in clinical practice. This system supports surgeons to identify a target intercostal artery by using patient image. The patient image and real body are matched by registration. Reference points of registration are anatomical landmarks of skeleton such as jugular notch, sternal angle, left anterior superior iliac spine, pubis, and spinous process. However, identification of spinous process was hard to doctors in operation. We developed a new registration method which X, Y and Z axis correspond to the Head-Foot, Right-Left and Anterior-Posterior directions. The specific feature is that identification of spinous process is not necessary. We evaluated errors with the new registration method using the retrospective 6 clinical data. We calculated fiducial localization error. As a result, errors of anterior points in the Head-Foot direction were less than 10 mm. We aimed to reduce the Head-Foot error as less than 20 mm because the ribs exist at intervals of approximately 40 mm in the Head-Foot direction. The new registration method was confirmed to be effective in the decision of approach to the target artery. Moreover, even when the point of the spinous process changed to the next spinous process of the set spinous processes, error was equivalent to the original point, therefore, using the present system, the identification of the spinous process can be unnecessary. It was concluded that newly-developed registration algorism is effective for doctors in identification of intercostal artery.

CiNii
2E33 Study of relationship between the impingement flow and activation of thrombogenic factors using whole blood in micro-channels

TEZUKA Ryo, YAGI Takanobu, WEI Ran, UMEZU Mitsuo

2016 ( 28 ) "2E33 - 1"-"2E33-5" 2016.01

　View Summary

Relationships between impingement of blood flow and thrombus formation mechanisms in human arteries are still hypothetical. This study investigated the relationship between different conditions of impingement and thrombus formations. Impingements of whole blood were created using Y-shaped and T-shaped micro-channels that were MPC coated. The velocities of impingement were set to be 0.2 m/s and 3.0 m/s. The whole blood was obtained from a healthy male volunteer. The whole blood at the impingement area was observed with an inverted microscope and a high-speed camera. Also, areas of thrombus ware measured on the obtained images using Image-Pro Plus to quantify the thrombus volume. The results showed that thrombus formation occurred in the Y-shaped impingement flow and didn't occur in the T-shaped impingement flow in either of the velocity. The thrombus formation in the Y-shaped impingement at low velocity occurred at the position shifted to the right and left rear from the bifurcation center. The thrombus formation at high velocity occurred at the bifurcation center. In addition, thrombus at low velocity peeled off easily than at high velocity. In conclusion, it was suggested that different impingement patterns affect the formation, formation point, and detachment rate of thrombus in the micro-channels.

CiNii
2E13 Patho-engineering Analysis of Human Cerebral Aneurysms : Study on Thinning Mechanism by infrastructure

TOBE Yasutaka, SUGIURA Takuma, SUTO Kenta, YAGI Takanobu, KAWAMURA Koichi, UMEZU Mitsuo, HAYASHI Yoshifumi, YOSHIDA Hirotaka, NISHITANI Kazutoshi, OKADA Yoshifumi, KITAHARA Shigemi

2016 ( 28 ) "2E13 - 1"-"2E13-5" 2016.01

　View Summary

This research investigated the properties of endothelial cells and wall structure of unruptured cerebral aneurysms to aim elucidation of cerebral aneurysm growth mechanism. Seven aneurysms were categorized into blood blister-like (under 80 μm), transition (80-100 μm), and hypertrophic (above 100 μm) lesion by its thickness and each lesion was observed with transmission electron microscope. The results showed that endothelial cell and wall property both improves as the thickness increases. In addition, number of layers constructing the aneurysm wall increased as the thickness increased. These results suggested that existence of endothelial cell may induce the thickening process of cerebral aneurysms and part of the thickening process may be creation of new layer from migration of smooth muscle cells and creation of fibrous layer.

CiNii
2E12 Study of the consistency of wall shear stress in healthy major human cerebral arteries

TAKANISHI Kiyofumi, YAGI Takanobu, WATANABE Mikihiko, UMEZU Mitsuo, NAKAMURA Masanori, HAYASHI Yoshifumi, YOSHIDA Hirotaka, NISHITANI Kazutoshi, OKADA Yoshifumi, KITAHARA Shigemi

2016 ( 28 ) "2E12 - 1"-"2E12-5" 2016.01

　View Summary

One of the problems with the cerebrovascular bypass surgery is that the adaptation mechanisms of the cerebral arteries are not clear for the medical professionals to prevent postoperative complications. In order to avoid postoperative complications, elucidation of the adaptation system in human cerebral arteries is necessary. It has been postulated that mean wall shear stress is maintained at a constant value in the arterial system; however, the credibility of the argument needs to be improve to apply the theory at clinical sites. This study investigates the consistency of the wall shear stress of the major cerebral arteries in 7 healthy volunteers using PC-MRI. The blood flowrate and the diameter of the arteries were plotted in the graph with blood flow rate against the third power of the diameter. The linear regression has been performed to see the correlation coefficient (R^2) to study the consistency of the arterial wall shear stress. Results showed a strong correlation coefficient (R^2=0.730±0.204) for the arteries with lower Wormersley number where the Hagen-Poiseuille assumption can be made. Therefore, it can be concluded that the wall shear stress is constant for the major cerebral arteries where the Hagen-Poiseuille flow can be produced.

CiNii
2E11 Study of the blood flow characteristics of vessel models from healthy volunteers at the favorite site of cerebral aneurysms

MURAYOSHI Takuma, YAGI Takanobu, TOBE Yasutaka, SUGIURA Takuma, UMEZU Mitsuo, HAYASHI Yoshifumi, YOSHIDA Hirotaka, NISHITANI Kazutoshi, OKADA Toshifumi, KITAHARA Shigemi

2016 ( 28 ) "2E11 - 1"-"2E11-5" 2016.01

　View Summary

There have not been any preceding research which refer to the relationship between morphological characteristics of cerebral artery and risks of cerebral aneurysm initiation from the perspective of blood flow. The objective of this research is to evaluate risks of cerebral aneurysm initiation using CFD analysis focusing on WSS vector variations due to impinging flow by investigating the correlation between morphological parameter and WSS vector variation for 13 healthy volunteers. The result indicated impingement of blood flow at MCA bifurcations in all cases. The average values of WSS vector variation was 357.7 degrees, bifurcation angle was 90.9 degrees, and inclination angle was 19.3 degrees. Results showed a low correlation coefficient (R^2=0.232) between bifurcation angles and WSS vector variations. In addition, no correlation for inclination angles and WSS vector variations was observed. This result suggests that widening of bifurcation angles due to morphological change by aging may resulted in larger WSS vector variation due to impinging flow, and larger risks of cerebral aneurysm initiation.

CiNii
2B25 Establishment of Non-clinical In Vitro Testing System and Methodology of Innovative Medical Devices for Approval : Facilitating Engineering Based Medicine

IWASAKI Kiyotaka, KASANUKI Hiroshi, ISEKI Hiroshi, NIIMI Shingo, HAISHIMA Yuji, MIYAZIMA Atsuko, KATO Reiko, SAKODA Hideyuki, UEMATSU Miyuki, MATSUHASHI Yuki, UMEZU Mitsuo

2016 ( 28 ) "2B25 - 1"-"2B25-5" 2016.01

　View Summary

We have developed in vitro test methodologies modeling in vivo practical-use situations, to quantitatively assess safety and effectiveness of innovative medical devices. We believe that expediting development of these in vitro methodology not only reinforce preclinical evaluation and enhance timely access to innovative medical devices for patients but also reduce potential risk when used in real-world clinical practice, because controlled clinical trials have certain limitation in fully demonstrating benefit and risk. With the grant from Ministry of Health, Labour and Welfare intended for "Promotional Project for Practical Application of Innovative Pharmaceutical, Medical Device, and Tissue Engineering Products", we have developed drafts on in vitro test guideline for "Durability testing methods for coronary artery stent", "Durability testing methods for vascular stent intended for Superficial femoral - Popliteal artery", and "Method for in vitro thrombogenicity testing for inflow cannula of left ventricular assist system". Further 5 guideline drafts are under preparation. Here, we introduce impacts of in vitro test methods modeling in vivo intended-use situations on expediting availability of new medical devices and timely assessment and management of risk.

CiNii
2B24 Experimental investigation of the influence of MPC coating on thrombus detachment from inflow cannula of EVAHEART

YAMAMOTO Yoshiki, IWASAKI Kiyotaka, MATSUHASHI Yuki, TAKAHASHI Azuma, HIRATA Mayuki, SAMESHIMA Kei, AOYAMA Yusuke, UMEZU Mitsuo

2016 ( 28 ) "2B24 - 1"-"2B24-4" 2016.01

　View Summary

Thrombus formation at the interface between left ventricular wall and the inflow cannula of left ventricular assist device (LVAD) remains to be an unsolved problem that induces complications in clinical practice. The aim of this study is to develop an in vitro airless circuit which produces flow and pressure environments in patients with a LVAD, and to investigate an influence of MPC coating of the inflow cannula of EVAHEART^[○!R] LVAD (Sun Medical Technology Research Co., Japan) on thrombus detachment from the inflow cannula. In the thrombogenicity test, two identical circuits except for the cannula were prepared to form a comparative study. Heparinized blood from a single porcine with activated clotting time ranged within 130-210 sec was circulated for 4.5 hours. The tests were performed under the combinations of the total flow rate of 4 L/min or 5 L/min, and the pump rotational speed of 1800, 1900 or 2000 rpm, respectively. It was elucidated that higher amount of thrombus formed on the MPC non-coated cannula compared with MPC coated cannula. However, there was no difference in the amount of thrombus detached between the two cannula (Student's t-test, p=0.91). From these results, it was elucidated that the MPC non-coated cannula yielded significantly lower proportion of thrombus detachment to thrombus formation than the MPC coated cannula (Student's t-test, p<0.05).

CiNii
2B22 Development of the evaluation method of the thrombogenecity of continuous hemofiltration devices using human blood

HIRATA Mayuki, IWASAKI Kiyotaka, MATSUHASHI Yuki, TAKAHASHI Azuma, YAMAMOTO Yoshiki, SAMESHIMA Kei, AOYAMA Yusuke, UMEZU Mitsuo

2016 ( 28 ) "2B22 - 1"-"2B22-4" 2016.01

　View Summary

Hemofilters are medical devices for assisting deteriorated renal functions, which purify the blood by removing pathogen and wastes. For continuous hemofilters, antithronbogenecity is one of the most important requirements. The aim of this study is to investigate the key parameters for the establishment of a reliable in vitro thrombogenecity testing methodology for continuous hemofilters using human blood from healthy volunteers. This study used adjusted activated clotting time of human blood drawn from healthy volunteers to 150-200 sec using heparin. The blood was circulated in the air-contactless circuit with flow and pressure in a clinical situation was reproduces. The tests were terminated when the inlet pressure elevated to 150 mmHg from the initiation pressure of 70 mmHg at the inlet. The average circulation duration was 6.5±1.7 hours(n=4). The circulation duration using human blood from healthy volunteers were shorter than using porcine blood which was previously reported. Hematocrit of porcine blood was lower than the human blood from healthy volunteers, whereas the hematocrit of porcine blood was comparable to dialysis patients. These data indicated the importance of hematocrit of blood in the assessment of the thrombogenecity of continuous hemofilters.

CiNii
2B15 Fatigue analysis on a self-expandable Nitinol stent deployed in femoral-popliteal artery under a multiple-load environment

TOKUTAKE Hirotsugu, IWASAKI Kiyotaka, ZHU Xiaodong, UMEZU Mitsuo

2016 ( 28 ) "2B15 - 1"-"2B15-3" 2016.01

　View Summary

The purpose of this study is to investigate influences of multi-loads and stenosis in femoral-popliteal artery on fracture of self-expandable stent using finite element analysis. A nitinol alloy stent was selected. The three-dimensional CAD models of the stent and vessel were constructed using SolidWorks. First, the stent was compressed by four cylinder models. Second, the stent was deployed in 50%, 60% and 75% stenotic artery models. Third, cyclic multi-loads were applied to the artery model. Multi-loads were two types. One is shortening of 12.7% and torsion of 0.28 degree/mm (Average). Another is shortening of 6.9% and torsion of 0.14 degree/mm (Half of average). When average loads were applied, strain amplitude of stent were 0.61%, 0.75%, and 0.87% in 50%, 60% and 75% stenotic model. When half of average loads were applied, those were 0.36%, 0.41%, and 0.54%. According to constant-life diagrams of average loads, when the stent was deployed in over 60% stenotic artery model, risk of fracture was high. This study indicated that risk of fracture is increased by multi-loads and stenosis.

CiNii
2B14 Assessment of in vitro performance of a stentless mitral valve (Normo valve) using accelerated fatigue tests system

HORIUCHI Yuki, IWASAKI Kiyotaka, USUI Kazuaki, KASEGAWA Hitoshi, UMEZU Mitsuo

2016 ( 28 ) "2B14 - 1"-"2B14-5" 2016.01

　View Summary

The aim of this study is to develop an accelerated fatigue tester for the Normo valve. Because the Normo valve has a unique structure similar to natural mitral valve, a novel accelerated fatigue tester which can mount the Normo valve and test in the condition recommended by the International Organization for Standardization (IS05840) was developed. We succeeded in producing the targeted closed duration percentage over the defined trans-valvular pressure gradient by adjusting the systolic and the drive frequency. The results showed that the drive condition of 10 Hz in drive frequency and 50% in systolic fraction met the requirement noted in ISO 5840.

CiNii
1H46 A study on time-dependent cell infiltration into the decellularized and sterilized bovine tendon in rat anterior cruciate ligament reconstruction

TAKANO Kazuya, ITO Masafumi, IMASU Hiroki, OKAMURA Akiyoshi, OKUDA Noriya, UMEZU Mitsuo, KATO Yoshiharu, IWASAKI Kiyotaka

2016 ( 28 ) "1H46 - 1"-"1H46-5" 2016.01

　View Summary

In the treatment of anterior cruciate ligament rupture, anterior cruciate ligament reconstruction is performed using autologous tendon. However, there are problems in the invasiveness and limitation in the source of autologous tendon. In order to solve these problems, a decellularized and sterilized bovine tendon has been developed. The aim of this study is to investigate cell infiltration into the decellularized and sterilized bovine tendon in rat anterior cruciate ligament reconstruction. In 4 and 26 weeks after the implantation, the tissues were explanted and subjected to hematoxylin-eosin staining. In this study, rat autologous tendon were also implanted to compare cell infiltration into the reconstructed tissues between the decellularized and sterilized bovine tendon and rat autologous tendon In the implantation period of 4 weeks, the number of cells in the decellularized and sterilized bovine tendon was higher than that in the rat autologous tendon In the implantation period of 26 weeks, the number of cells in the decellularized and sterilized bovine tendon and that in the rat autologous tendon became comparable. In the implantation period of 26 weeks, the number of cells in the decellularized and sterilized bovine tendon and that in rat anterior cruciate ligament also became comparable. These data indicated that the decellularized and sterilized bovine tendon has a promise as a prosthesis for anterior cruciate ligament reconstruction.

CiNii
1H45 Investigation of mechanical properties of Achilles' tendon autograft after ovine anterior cruciate ligament reconstruction

IMASU Hiroki, ITO Masafumi, TAKANO Kazuya, OKAMURA Akiyoshi, OKUDA Noriya, UMEZU Mitsuo, KATO Yoshiharu, IWASAKI Kiyotaka

2016 ( 28 ) "1H45 - 1"-"1H45-5" 2016.01

　View Summary

We aimed to investigate mechanical properties of Achilles' tendon autograft after ovine anterior cruciate ligament reconstruction. Mature three female ovine were used in this study. In each ovine, the right knee underwent anterior cruciate ligament reconstruction. They were sacrificed at 13 weeks after surgery. In each ovine, both the knees were harvested, and the left knee was used to obtain the data of the native anterior cruciate ligament. Drawer test for stability evaluation and tensile test for evaluation of mechanical properties were performed. The knee was mounted on a jig with 5 degrees of freedom for tensile testing, four cycles of anterior-posterior shear loads (50 N) were applied to the knee at 30°, 60° and 90° of the flexion with a cross head speed set at 20 mm/min. The displacement of the femur relative to tibia was defined as the anterior-posterior translation of the knee. (1) Stress relaxation test (5 N, 10 min), (2) cyclic load test (0-50 N, 10 cycles, 10 mm/min), and (3) tensile test (300 mm/min) were performed in turn. Before each testing, tissue cross-sectional area was measured with the device using a laser displacement sensor. At 13 weeks after the implantation, the anterior-posterior translation of the reconstructed knee was greater than native anterior cruciate ligament. Ultimate strength and maximum Young's modulus of the femur-graft-tibia complex were smaller than native anterior cruciate ligament. These testing methods presented here is effective to gain insight into in vivo biomechanical remodeling of reconstructed tissues.

CiNii
1E42 Study on the relationship between modeling and energy loss of anastomotic configuration for anastomosis assessment

OYAMA Daisuke, PARK Young Kwang, YAGI Takanobu, IWASAKI Kiyotaka, OSAKA Shinichi, UMEZU Mitsuo

2016 ( 28 ) "1E42 - 1"-"1E42-4" 2016.01

　View Summary

Off-pump CABG surgery requires high level of techniques. The surgeon must complete the anastomosis of two millimeter wide arteries within ten minutes on beating condition. Due to its difficulty, an effective training platform of DRY LAB with assessments is in strong need. This study investigated the models of anastomosis configurations and a relationship between the model and the energy loss (EL) using a beating heart simulator (BEAT, EBM) and coronary artery model (YOUCAN, EBM) which were developed from this research. The models for the analysis were chosen based on the actual EL; low (X: 42 μW), medium (Y: 196 μW) and high (Z: 362 μW) values. The effective cross-sectional areas were set by taking the cross-sectional areas from the mainstreams. The calculated EL was calculated using Hagen-Poiseuille because energy loss is inversely proportional to the square of the minimum effective cross-sectional area in a Hagen-Poiseuille flow. Results indicated that the change of the velocity distribution of the area in Y and Z were greater than those in X. The minimum effective cross-sectional areas were 2.1 mm^2 (X), 1.2 mm^2 (Y), 0.8 mm^2 (Z). Therefore, it was confirmed that mainstream could not utilize the anastomosis configuration efficiently in Y and Z. In addition, it was found that the calculated EL and the actual EL had a strong correlation, and the minimum effective cross-sectional area influenced the actual EL strongly.

CiNii
1E41 The relationship between demand blood flow and supply blood flow before and after revascularization

WATANABE Mikihiko, YAGI Takanobu, TAKANISHI Kiyofumi, KATAOKA Hiroharu, YAMAMOTO Akihide, IGUCHI Satoshi, IIDA Hidehiro, NAKAMURA Masanori, UMEZU Mitsuo

The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2016 ( 0 ) _1E41 - 1_-_1E41-4_ 2016 [Refereed]

　View Summary

Cerebral revascularization is a general surgery for vascular lesions. Operative procedures are decided based on surgeon's experience, however unpredictable complications are still a problem. The aim of our study is to predict complications before operation by identifying the mechanism of cerebral hemodynamics adaptations. It is considered that blood flow is regulated for meeting demand of tissue cells. There is a little study about the relationship between blood flow in cerebral arteries and cerebral demand. In this study, the total of flow rate in both sides internal carotid arteries and basilar artery is 'supply blood flow', and gray matter volume (V_G) and white matter volume (V_W) are multiplied by each literature cerebral blood flow (k_G, k_W) to calculate 'demand blood flow' (V_G・K_G+V_W・K_W). For 14 healthy volunteers and 2 patients (aneurysm and ischemic), the ratio of difference between demand and supply blood flow on the basis of supply values are studied. As the result, difference between supply blood flow and demand blood flow is -11.3% in healthy subjects. In a case of aneurysm, difference rate is low before and after surgery. In a case of ischemic, there is a high difference rate (59.1%). However, difference becomes lower (12.1%) by supply blood flow increase after operation. It is suggested that difference rate is available for diagnosis of ischemic.

DOI CiNii
1A22 Examination of the blood flow effects on the thrombus formation by real-time visualization using optical coherence tomography

MATSUHASHI Yuki, TAKAHASHI Azuma, HIRATA Mayuki, YAMAMOTO Yoshiki, SAMESHIMA Kei, AOYAMA Yusuke, UMEZU Mitsuo, IWASAKI Kiyotaka

2016 ( 28 ) "1A22 - 1"-"1A22-3" 2016.01

　View Summary

Thrombus formations in medical devices are unsolved issue. If a reliable in vitro real-time visualization method is established, it will contribute the development and improvement of anti-thrombogenic medical devices. The aim of this study is to develop a real-time thrombus visualization system with an optical coherence tomography (OCT) and to reveal an influence of local blood flow on thrombus growth. We focus on the inlet and outlet part of connecters. The circuit was consisted of a roller pump, a reservoir, and resistance. The circuit volume was 50 ml. The blood flow rate and pressure were regulated to 100 ml/min and 70 mmHg. To visualize cross-sectional imaging of thrombus, we used a SS-OCT system with center wave-length of 1330 nm. OCT images were obtained every 10 minutes for 50 minutes. Test were performed 6 times. A fresh porcine whole blood with activated clotting time of approximately 200 sec was circulated. Thrombus-formed area increased with time at the outlet part of the connecter, however, the thrombus-formed area didn't increase at the inlet part. The part where thrombus-formed are increased was related to a flow-separation area. Flow-separation would be a cause to form such an increasingly thrombus. We revealed that the local blood flow is important not only for thrombus formation but also stability of thrombus-formed at the connecter.

CiNii
1A16 Development of a calcified aortic valve model for the assessment of paravalvular leak of transcatheter aortic valve

OBAMA Kazuto, FUKUYAMA Daiki, TAKAHASHI Azuma, AOYAMA Yusuke, TANAKA Yutaka, UMEZU Mitsuo, SAITO Shigeru, IWASAKI Kiyotaka

2016 ( 28 ) "1A16 - 1"-"1A16-5" 2016.01

　View Summary

We aimed to develop a calcified aortic valve model for the evaluation of paravalvular leak of a transcatheter aortic valve. We fabricated a calcified aortic valve model using silicone based on a CT image of the pre-operation of the patient who received treatment with a transcatheter aortic valve. In addition, we fabricated a thoracic aorta model and an abdominal aorta model because these three dimensional morphology would affect the insertion procedure of the transcatheter valve. These models were installed into a chamber, and the other space of the models were filled with a glycerol solution with the refractive index and viscosity of 1.410±0.002 and 5.96 mPa・s respectively, in order to adjust the expansion rate of the valve annulus and to measure the expansion range by a lazer system in pulsatile flow and pressure environments. Using the test system, the maximum and minimum cross-sectional area of the valve annulus in systole and diastole in the pulsatile flow circuit could be adjusted to these in the referenced patients' data. The pulsatile flow system with patient specific aortic valve, thoracic aorta and abdominal aorta model would be useful to quantify the paravalvular leak performance of the transcatheter aortic valve.

CiNii
Buttock Dummy with Force Sensors for Assessment of Deep Tissue Injury Risk

Kohei Kanaya, Kunihiro Ogata, Tsuyoshi Nakayama, Eiichi Ono, Mitsuo Umezu

2016 IEEE/SICE INTERNATIONAL SYMPOSIUM ON SYSTEM INTEGRATION (SII) 496 - 501 2016 [Refereed]

　View Summary

Prevention of pressure ulcers, which result from persistent mechanical loading of soft tissues, is a common issue among wheelchair users. In the case of deep tissue injury (DTI), it is difficult to predict where tissue breakdown will occur, as it initiates from tissues under the skin. In this paper, a new methodology to assess the risk of DTI using a compliant buttock dummy is proposed. The dummy is composed of pelvis model with six-axis force sensors and silicone rubber covering it to imitate the anatomical form of a human buttock. Six-axis force sensors attached to the pelvis model enable the measurement of external forces and moments during the sitting posture and estimate points of action on bony prominences such as ischial tuberosities by an algorithm. Experiments have been performed to test the accuracy of position estimation by placing point load on the bony prominences model. Next, the relationship between external forces and internal pressure has been confirmed by adhering pressure sensors on the surface of rigid models covered by soft materials. The results suggested the potential of the proposed dummy for the assessment tool of DTI risk.

DOI

Scopus

4

Citation

(Scopus)
A fibril-based structural constitutive theory reveals the dominant role of network characteristics on the mechanical behavior of fibroblast-compacted collagen gels

Zhonggang Feng, Yuki Ishiguro, Kyohei Fujita, Tadashi Kosawada, Takao Nakamura, Daisuke Sato, Tatsuo Kitajima, Mitsuo Umezu

Biomaterials 67 365 - 381 2015.10

　View Summary

In this paper, we present a general, fibril-based structural constitutive theory which accounts for three material aspects of crosslinked filamentous materials: the single fibrillar force response, the fibrillar network model, and the effects of alterations to the fibrillar network. In the case of the single fibrillar response, we develop a formula that covers the entropic and enthalpic deformation regions, and introduce the relaxation phase to explain the observed force decay after crosslink breakage. For the filamentous network model, we characterize the constituent element of the fibrillar network in terms its end-to-end distance vector and its contour length, then decompose the vector orientation into an isotropic random term and a specific alignment, paving the way for an expanded formalism from principal deformation to general 3D deformation
and, more important, we define a critical core quantity over which macroscale mechanical characteristics can be integrated: the ratio of the initial end-to-end distance to the contour length (and its probability function). For network alterations, we quantitatively treat changes in constituent elements and relate these changes to the alteration of network characteristics. Singular in its physical rigor and clarity, this constitutive theory can reproduce and predict a wide range of nonlinear mechanical behavior in materials composed of a crosslinked filamentous network, including: stress relaxation (with dual relaxation coefficients as typically observed in soft tissues)
hysteresis with decreasing maximum stress under serial cyclic loading
strain-stiffening under uniaxial tension
the rupture point of the structure as a whole
various effects of biaxial tensile loading
strain-stiffening under simple shearing
the so-called "negative normal stress" phenomenon
and enthalpic elastic behaviors of the constituent element. Applied to compacted collagen gels, the theory demonstrates that collagen fibrils behave as enthalpic elasticas with linear elasticity within the gels, and that the macroscale nonlinearity of the gels originates from the curved fibrillar network. Meanwhile, the underlying factors that determine the mechanical properties of the gels are clarified. Finally, the implications of this study on the enhancement of the mechanical properties of compacted collagen gels and on the cellular mechanics with this model tissue are discussed.

DOI PubMed

Scopus

5

Citation

(Scopus)
A fibril-based structural constitutive theory reveals the dominant role of network characteristics on the mechanical behavior of fibroblast-compacted collagen gels

Zhonggang Feng, Yuki Ishiguro, Kyohei Fujita, Tadashi Kosawada, Takao Nakamura, Daisuke Sato, Tatsuo Kitajima, Mitsuo Umezu

BIOMATERIALS 67 365 - 381 2015.10 [Refereed]

　View Summary

In this paper, we present a general, fibril-based structural constitutive theory which accounts for three material aspects of crosslinked filamentous materials: the single fibrillar force response, the fibrillar network model, and the effects of alterations to the fibrillar network. In the case of the single fibrillar response, we develop a formula that covers the entropic and enthalpic deformation regions, and introduce the relaxation phase to explain the observed force decay after crosslink breakage. For the filamentous network model, we characterize the constituent element of the fibrillar network in terms its end-to-end distance vector and its contour length, then decompose the vector orientation into an isotropic random term and a specific alignment, paving the way for an expanded formalism from principal deformation to general 3D deformation; and, more important, we define a critical core quantity over which macroscale mechanical characteristics can be integrated: the ratio of the initial end-to-end distance to the contour length (and its probability function). For network alterations, we quantitatively treat changes in constituent elements and relate these changes to the alteration of network characteristics. Singular in its physical rigor and clarity, this constitutive theory can reproduce and predict a wide range of nonlinear mechanical behavior in materials composed of a crosslinked filamentous network, including: stress relaxation (with dual relaxation coefficients as typically observed in soft tissues); hysteresis with decreasing maximum stress under serial cyclic loading; strain-stiffening under uniaxial tension; the rupture point of the structure as a whole; various effects of biaxial tensile loading; strain-stiffening under simple shearing; the so-called "negative normal stress" phenomenon; and enthalpic elastic behaviors of the constituent element. Applied to compacted collagen gels, the theory demonstrates that collagen fibrils behave as enthalpic elasticas with linear elasticity within the gels, and that the macroscale nonlinearity of the gels originates from the curved fibrillar network. Meanwhile, the underlying factors that determine the mechanical properties of the gels are clarified. Finally, the implications of this study on the enhancement of the mechanical properties of compacted collagen gels and on the cellular mechanics with this model tissue are discussed. (C) 2015 Elsevier Ltd. All rights reserved.

DOI

Scopus

5

Citation

(Scopus)
Time Course of Cell Sheet Adhesion to Porcine Heart Tissue after Transplantation

Dehua Chang, Tatsuya Shimizu, Yuji Haraguchi, Shuai Gao, Katsuhisa Sakaguchi, Mitsuo Umezu, Masayuki Yamato, Zhongmin Liu, Teruo Okano

PLOS ONE 10 ( 10 ) 2015.10 [Refereed]

　View Summary

Multilayered cell sheets have been produced from bone marrow-derived mesenchymal stem cells (MSCs) for investigating their adhesion properties onto native porcine heart tissue. Once MSCs reached confluence after a 7-day culture on a temperature-responsive culture dish, a MSCs monolayer spontaneously detached itself from the dish, when the culture temperature was reduced from 37 to 20 degrees C. The basal extracellular matrix (ECM) proteins of the single cell sheet are preserved, because this technique requires no proteolytic enzymes for harvesting cell sheet, which become a basic building block for assembling a multilayer cell sheet. The thickness of multilayered cell sheets made from three MSC sheets was found to be approximately 60 mu m. For investigating the adhesion properties of the basal and apical sides, the multilayered cell sheets were transplanted onto the surface of the heart's left ventricle. Multilayered cell sheets were histological investigated at 15, 30, 45 and 60 minutes after transplantation by hematoxylin eosin (HE) and azan dyes to determine required time for the adhesion of the multilayered sheets following cell-sheet transplantation. The results showed that only the basal side of multilayered cell sheets significantly enhanced the sheets adhesion onto the surface of heart 30 minutes after transplantation. This study concluded that (1) cell sheets had to be transplanted with its basal side onto the surface of heart tissue and (2) at least 30 minutes were necessary for obtaining the histological adhesion of the sheets to the heart tissue. This study provided clinical evidence and parameters for the successful application of MSC sheets to the myocardium and allowed cell sheet technology to be adapted clinical cell-therapy for myocardial diseases.

DOI

Scopus

23

Citation

(Scopus)
Characterizing and modulating the mechanical properties of hydrogels from ventricular extracellular matrix

Fujita, Kyohei, Tuchida, Yuuki, Seki, Hiroki, Kosawada, Tadashi, Feng, Zhonggang, Shiraishi, Yasuyuki, Sato, Daisuke, Nakamura, Takao, Umezu, Mitsuo

2015 10th Asian Control Conference: Emerging Control Techniques for a Sustainable World, ASCC 2015 2015.09 [Refereed]

　View Summary

© 2015 IEEE. In order to differentiate pluripotent stem cells to cardiomyocytes, the most general method is to expose stem cells to various growth factors related to cardiogenesis. However, a novel method has been reported to induce cardiac differentiation of human ES cells without supplemental growth factors by culturing embryoid body of human ES cells in hybrid gels composed of cardiac extracellular matrix (ECM) and type I collagen. On the other hand, mechanical properties of scaffold is one of the critical cue for differentiation of stem cells. However, it has not been thoroughly investigated the mechanical properties of the scaffold made from cardiac ECM in view of this and other reports about the differentiation of stem cells into cardiomyocytes using cardiac ECM scaffold. In this study, we fabricated bio-hydrogels composed of goat ventricular extracellular matrix, and investigated the mechanical properties by means of uniaxial compression test. It showed that the ECM gels possess viscoelastic property. The elastic modulus K1 in modified non-linear Kelvin model is 9.5 Pa for these gels and K2 is 814.7 Pa. Moreover, we were able to improve the elastic moduli K1 and K2 up to 139.7 Pa and 2023.9 Pa, respectively, by chemical treatment using EDAC.

DOI

Scopus

5

Citation

(Scopus)
Medical image-based analysis of flow in heart with congenital heart disease: Numerical simulation of intraventricular flow

Chen, Lijun, Liu, Jinlong, Liu, Jinlong, Hong, Haifa, Sun, Aimin, Liu, Jinfen, Zhang, Yuqi, Umezu, Mitsuo

2015 10th Asian Control Conference: Emerging Control Techniques for a Sustainable World, ASCC 2015 2015.09 [Refereed]

　View Summary

© 2015 IEEE. Quantitatively analyze the characteristics of intraventricular flow is critical for the diagnosis of congenital heart disease (CHD). Although several techniques are applied in clinic currently, the information which they provided is not satisfied with the requirement of the therapies of CHD. Here, we introduced the method of computational fluid dynamics (CFD) to investigate the intraventricular hemodynamics using a reconstructed model of left ventricle (LV) based on cardiac magnetic resonance (CMR) images. A large, counterclockwise, vortex was observed. It persisted in the periods of slow filling phase and atrial contraction phase in diastole. A smaller vortex was found around the outflow tract. An annular vortex is formed in the base region downstream of the mitral orifice. The vortices vanished quickly at the end-diastole. These results indicate the technique of CFD is a promising tool which can be used to evaluate the hemodynamics in LV. Understanding the characteristics of intraventricular flow is helpful for the improvement of CHD.

DOI

Scopus

1

Citation

(Scopus)
Design a novel asymmetric bifurcating microfluidic channel for cell separation by size

Feng, Zhonggang, Nakamura, Takao, Sato, Daisuke, Kitajima, Tatsuo, Umezu, Mitsuo

2015 10th Asian Control Conference: Emerging Control Techniques for a Sustainable World, ASCC 2015 2015.09 [Refereed]

　View Summary

© 2015 IEEE. In this paper, we exhibit a novel asymmetric bifurcating microchannel for cell separation by size. As developing this microchannel, we proposed the design and optimization criteria, which included the design of inlet and outlet based on the analysis of the Segre-Silberberg effect and the optimization principle to render the migration force at the bifurcation portion as great as possible. Experiments using rat fibroblasts and red blood cells verified these design principles and confirmed the separation function with the optimal design. The simple configuration of the microchannel makes it feasible to serialize several such microchannels within 1.0×1.0 mm2 space and to achieve enrichment rate as high as 103∼104 folds.

DOI

Scopus
Hemodynamic analysis of controlled antegrade pulmonary blood flow after bidirectional cavopulmonary anastomosis

Hong, Haifa, Liu, Jinfen, Qiu, Lisheng, Liu, Jinlong, Liu, Jinlong, Qian, Yi, Wang, Qian, Umezu, Mitsuo

2015 10th Asian Control Conference: Emerging Control Techniques for a Sustainable World, ASCC 2015 2015.09 [Refereed]

　View Summary

© 2015 IEEE. To preserve the controlled antegrade pulmonary blood flow (APBF) is one of contentious issues in the procedure of bidirectional cavopulmonary anastomosis (BCPA) for the treatment of single-ventricle physiology. Here, we reported our patient-specific researches of the controlled APBF on local hemodynamics of pulmonary artery by using the techniques of computational fluid dynamics (CFD). Computer-aided design was employed to create a vascular model without the APBF based on the three-dimensional pulmonary geometry of a patient. We defined several indexes to quantitatively evaluate the effects of the APBF. The results show an obvious elevation of local static pressure, WSS and energy loss. This indicates the local hemodynamics is greatly influenced by the pulsatile blood flow. The controlled APBF may benefit subsequent Fontan procedure.

DOI

Scopus

1

Citation

(Scopus)
Hemodynamic influence of surgical methods on systemic-to-pulmonary shunt: Modified Blalock-Taussig shunt versus Melbourne shunt

Wang, Qian, Qian, Yi, Hong, Haifa, Sun, Qi, Sun, Yanjun, Liu, Jinfen, Liu, Jinlong, Liu, Jinlong, Umezu, Mitsuo

2015 10th Asian Control Conference: Emerging Control Techniques for a Sustainable World, ASCC 2015 2015.09 [Refereed]

　View Summary

© 2015 IEEE. The systemic-to-pulmonary artery shunt is an effective procedure widely used in the therapy of congenital heart defect (CHD). To better understand the local flow features may provide hemodynamic information for patient-specific surgical design. Here, we report on three-dimensional (3D) hemodynamic analysis of two schemes of this procedure; the modified Blalock-Taussig shunt (MBTS) and Melbourne shunt. A patient-specific 3D model after the MBTS was reconstructed. We applied the technique of computer-aided design (CAD) to virtually create a model of Melbourne shunt based on vascular anatomical position. Pressure drop, wall shear stress (WSS), streamlines and blood flow distribution ratio were calculated by computational fluid dynamics (CFD). We found more blood distribution and high pressure were observed at pulmonary artery in Melbourne shunt. This indicates to control the balance of blood flow distributed to systemic and pulmonary circulation small size shunt will be more favorable in the procedure of Melbourne shunt. The choice of surgery schemes for patient-specific surgery can be done by the analysis local hemodynamics.

DOI

Scopus

2

Citation

(Scopus)
Growth effects of anastomosis site on patient-specific aortic hemodynamics after coarctation correction: A numerical study

Mao, Le, Zhang, Weimin, Hong, Haifa, Sun, Qi, Huang, Junrong, Liu, Jinfen, Liu, Jinlong, Liu, Jinlong, Zhu, Zhongqun, Qian, Yi, Wang, Qian, Umezu, Mitsuo

2015 10th Asian Control Conference: Emerging Control Techniques for a Sustainable World, ASCC 2015 2015.09 [Refereed]

　View Summary

© 2015 IEEE. Coarctation of the aorta (CoA) is one of the most common congenital cardiac anomalies that could be corrected by surgery. However, the effects of surgical anastomosis on aortic arch flow are still unknown. In this study, a unique three-dimensional way was utilized to measure the growth of anastomotic site and computational fluid dynamics (CFD) was applied to investigate the hemodynamic effects of the growth of anastomosis site on patient-specific aortic arch flow before, 1 year and 2 years after surgery. The volume of anastomotic site, distribution of total pressure, wall shear stress (WSS), streamlines, energy efficiency and flow distribution ratio were calculated. The results indicated that the volume of anastomotic site has grown at 2-year follow-up. The total pressure and WSS were more uniformly distributed, whereas the three branches of aortic arch showed varying degrees of hypoperfusion. Energy efficiency increased obviously as the growth of anastomotic site. Our results implied that the numerical methods can be applied to evaluate the long-term effects of anastomosis site growth on aortic arch flow.

DOI

Scopus
Computational aerodynamics of long segment congenital tracheal stenosis with bridging bronchus

Zhu, Limin, Liu, Jinlong, Liu, Jinlong, Zhang, Weimin, Sun, Qi, Hong, Haifa, Du, Zhou, Liu, Jinfen, Qian, Yi, Wang, Qian, Umezu, Mitsuo

2015 10th Asian Control Conference: Emerging Control Techniques for a Sustainable World, ASCC 2015 2015.09 [Refereed]

　View Summary

© 2015 IEEE. Long segment congenital tracheal stenosis (LSCTS) is one of most severe malformation with high mortality rate and dismal prospective. Hypoventilation is the main issue for the death of children with LSCTS after surgical correction. However, currently, little information is available on local aerodynamics to disclose the reasons for the improvement of such therapies, especially LSCTS with distal bronchus stenoses. Here, we investigated a patient-specific model of LSCTS with complete tracheal rings and bridging bronchus (BB). Computational fluid dynamics (CFD) was applied to analyze the local aerodynamics around BB before and after tracheal surgery in inspiratory phase and expiratory phase. Average pressure drop, wall shear stress, streamlines and energy loss were calculated to evaluate the surgical outcomes. The results indicate the airflow at the trachea and BB become more turbulent in expiration phase than that in inspiration phase. The turbulence increases the workloads of respiration in expiration phase. It should be the cause for postoperative hypoventilation. To study the local aerodynamics is helpful for the improvement of surgical therapies of the LSCTS.

DOI

Scopus

4

Citation

(Scopus)
MEDICAL IMAGE-BASED HEMODYNAMIC ANALYSIS FOR MODIFIED BLALOCK-TAUSSIG SHUNT

Jinlong Liu, Qi Sun, Haifa Hong, Yanjun Sun, Jinfen Liu, Yi Qian, Qian Wang, Mitsuo Umezu

JOURNAL OF MECHANICS IN MEDICINE AND BIOLOGY 15 ( 3 ) 2015.06 [Refereed]

　View Summary

Modified Blalock-Taussig (mB-T) shunt is an effective palliative surgical method in the treatment of cyanotic congenital heart diseases. Although the surgical technique has improved over the years, it is still a challenge to control appropriate blood flow through the conduit. The formation of thrombosis in the conduit after the mB-T shunt may lead to severe desaturation or reoperation in some cases. Here, we applied the method of computational fluid dynamics (CFD) to study a patient-specific case based on medical images after the mB-T shunt. The real-time velocities derived from echocardiography and the pulsatile pressure waves measured during the operation were utilized as boundary conditions to physiologically capture the blood flow information in simulation. The calculated results were coincident with clinical measurements. Local pressure, blood flow distribution, streamlines, wall shear stress (WSS) and centrifugal force in the bended conduit were investigated. The results indicate that pressure decreases greatly through the conduit. The combined action of pulsatile pressure and WSS may lead to the damage of blood cells. The computational hemodynamics can be applied in future studies of establishing quantitative standards to evaluate surgical outcomes of the mB-T shunt.

DOI

Scopus

14

Citation

(Scopus)
光干渉断層装置を用いた生体外での血栓観察法の検討

松橋祐樹, 高西清文, 高橋東, 梅津光生, 岩崎清隆

第38回日本バイオレオロジー学会年会プログラム・抄録集 64 2015.06
細胞シートを用いた機能的な肝組織モデルおよび薬効試験デバイスの構築

亀井翔太, 李力, 坂口勝久, 清水達也, 梅津光生

第38回日本バイオレオロジー学会年会プログラム・抄録集 61 2015.06
無細胞化腱を用いた異種動物の前十字靭帯再建による再生能評価

岩崎清隆, 伊藤匡史, 高野和也, 井桝浩貴, 奥田慶也, 岡村昭慶, 加藤義治, 梅津光生

第38回日本バイオレオロジー学会年会プログラム・抄録集 63 2015.06
前立腺癌イメージングを目的とした7a-[18F]Testosteroneのプローブ開発

中喬介, 梅津光生, 岡本真由美, 石渡喜一, 豊原潤

日本ケミカルバイオロジー学会第10回年会抄録集 104 2015.06
Characterizing and Modulating the mechanical properties of hydrogels form ventricular extracellular matrix

Kyohei Fujita, Yuuki Tsuchida, Hiroki Seki, Tadashi Kosawada, Zhonggang Feng, Daisuke Sato, Takao Nakamura, Yasuyuki Shiraishi, Mitsui Umezu

ASCC 2015 10th Asian Control Conference Proceeding 768 - 772 2015.06 [Refereed]
Hemodynamic influence of surgical methods on blalock-to-pulmonary shunt: modified blalock taussig shunt versus Melbourne shunt

Qian Wang, Haifa Hong, Qi Sun, Yanjin Sun, Jinfen Liu, Jinlong Liu, Yi Qian, Mitsuo Umezu

ASCC 2015 10th Asian Control Conference Proceeding 1498 - 1502 2015.06 [Refereed]
Hemodynamic analysis of controlled antegrade pulmonary blood flow after bidirectional cavopulmonary anastomosis

Haifa Hong, Jinfen Liu, Lisheng Qiu, Jinlong Liu, Qian Wang, Yi Qian, Mitsuo Umezu

ASCC 2015 10th Asian Control Conference Proceeding 1493 - 1487 2015.06 [Refereed]
Medical image –based analysis of flow in heart with congenital heart disease: Numerical simulation of intraventricular flow

Lijun Chen, Jinlong Liu, Haifa Hong, Aimin Sun, Jinfen Liu, Yuqi Zhang, Mitsuo Umezu

ASCC 2015 10th Asian Control Conference Proceeding 1837 - 1842 2015.06 [Refereed]
Design a novel asymmetric bifurcating microfluidic channel for cell separation by size

Zhonggang Feng, Takao Nakamura, Daisuke Sato, Tatsuo Kitajima, Mitsuo Umezu

ASCC 2015 10th Asian Control Conference Proceeding 991 - 995 2015.06 [Refereed]
有限要素解析を用いた繰り返し屈曲下での冠動脈ステントの疲労破断予測

岩崎清隆, 朱暁冬, 徳武祐諭, 梅津光生

第54回日本生体医工学会平成27年度第1回医用アクチュエーション研究会 2015.05
Investigation of influences of flow field in the pert of hemofilters on thrombus formation

Azuma Takahashi, Kiyotaka Iwasaki, Sara Suzuki, Yusuke Aoyama, Yuki Matsuhashi, Mayuki Hirata, Yoshiki Yamamoto, Mitsuo Umezu

Biorheology The official journal of the international society of biorhelogy 155 2015.05
In vitro assessment of novel stentless valve in the mitral position

Satoshi Kainuma, Hitoshi Kasegawa, Shigeru Miyagawa, Hiroyuki Nishi, Hitoshi Yaku, shuichiro Takanashi, kazuhiro Hashimoto, Yukikatsu Okada, Satoshi Nakatani, Mitsuo Umezu, Takashi Daimon, Taichi Sakaguhi, Koichi Toda, Yoshiki Sawa

Circulation Journal 79 ( 3 ) 553 - 559 2015.03 [Refereed]
装着後に溶血をきたしたニプロ製拍動型補助人工心臓の溶血特性評価試験

平田麻由紀, 岩﨑清隆, 松橋祐輝, 高橋東, 山本祥宜, 藤原立樹, 新井裕国, 梅津光生

第43回人工心臓と補助循環懇話会学術集会プログラム・抄録集 66 2015.02
迷走神経刺激装置の2度の審査について

小野村章, 伊関洋, 岩﨑清隆, 梅津光生

第9回医療機器に関するレギュラトリーサイエンス研究会発表抄録集 8 2015.02
当施設における頸動脈ステント留置術(CAS)の成績向上に向けての工夫,

山家弘雄, 越道慎一郎, 三木潤一郎, 仲寛, 梅津光生

第9回医療機器に関するレギュラトリーサイエンス研究会発表抄録集 10 2015.02
生体外における微小循環を模擬としたヒト三次元組織モデルの構築

佐藤祐樹, 坂口勝久, 清水達也, 梅津光生, 岡野光夫

第14回日本再生医療学会総会プログラム抄録, 再生医療増刊号,vol.14 203 2015.02
薬効試験に向けた機能的な肝細胞シートの作成

亀井翔太, 李力, 坂口勝久, 清水達也, 梅津光生, 岡野光夫

第14回日本再生医療学会総会プログラム抄録再生医療増刊号,vol.14 244 2015.02
低温環境下潅流培養による三次元心筋組織の構築,,pp224,,2015.2(横浜 2015.3月)

松浦加奈, 日向裕人, 坂口勝久, 清水達也, 梅津光生, 岡野光夫

第14回日本再生医療学会総会プログラム抄録再生医療増刊号,vol.14 224 2015.02
True Engineering–Medical Collaboration on Vascular Surgery

Umezu Mitsuo

Jpn. J. Vasc. Surg. 24 ( 4 ) 747 - 753 2015

　View Summary

In this seminar, I discuss three types of applied research in which collaborations between biomedical engineers and medical doctors can advance the surgical field of vascular grafting. First, I describe a mock circulatory system designed to simulate regional hemodynamics and input impedance in the human aorta. This circuit can estimate the cardiac work that results from implanting or replacing a synthetic aortic graft. Simulation shows that replacement of an aortic graft made of silicone rubber with one made of polytetrafluoroethylene (PTFE) increases cardiac work significantly. Second, I show how technology originally developed for neurosurgical navigation can be applied to the replacement of a thoraco-abdominal aortic aneurysm with a PTFE graft. Here, a registration method combines visual relationships between the real operative space and a three-dimensional space constructed from images obtained by computed tomography. The system employs a phantom thoraco-abdominal artery to accurately locate the Adamkiewicz artery that often, but not always, arises from a left inferior intercostal artery. To date, this navigation system has contributed to the surgical success of eighty-six aortic grafts. Third, I introduce a computational fluid dynamic (CFD) program to predict the distribution of blood flow in a three-branch graft during thoracic endovascular aortic repair (TEVAR). Phase-contrast magnetic resonance angiography image (PC-MRI) of the blood flow distribution determines the initial conditions in patients and healthy individuals. Calculations show a permissible 3% decrease in flow in the descending aorta after surgical endovascular debranching. Finally, I emphasize the importance of educating and training new leaders of Medical Regulatory Science to achieve a true engineering-medical collaboration at Tokyo Women's and Waseda University Joint Institution for Advances Biomedical Sciences.

DOI CiNii
In Vivo Assessment of Novel Stentless Valve in the Mitral Position

Kainuma Satoshi, Kasegawa Hitoshi, Miyagawa Shigeru, Nishi Hiroyuki, Yaku Hitoshi, Takanashi Shuichiro, Hashimoto Kazuhiro, Okada Yukikatsu, Nakatani Satoshi, Umezu Mitsuo, Daimon Takashi, Sakaguchi Taichi, Toda Koichi, Sawa Yoshiki, on behalf of, the, Committee of the, Japanese, Society of, Stentless Mitral Valve

JAPANESE CIRCULATION JOURNAL 0 ( 0 ) 2015

　View Summary

Background:We conducted in vivo examinations of a newly designed stentless mitral valve (SMV), formed by suturing 2 leaflets with the "legs" serving as chorda tendinea, made from bovine pericardium, to a flexible ring.Methods and Results:Seven pigs underwent implantation of the SMV constructed with a 23-mm (n=5) or 25-mm (n=2) Duran ring. Baseline echocardiography examinations were used to evaluate the annular anteroposterior diameter, and distance between the mitral annulus (MA) and papillary muscles (PMs) to determine SMV-leg length. After removing the native valve, the SMV-legs were fixed to the anterior and posterior PMs, followed by fixation of the ring to the native MA. Immediately after surgery, all animals presented none or trivial mitral regurgitation, with mean and peak trans-SMV pressure gradient values of 1.9±0.8 and 6.0±3.1 mmHg, respectively. The mean length of the SMV-leg was 19.4±3.9 mm, which correlated with the distance between anterior and posterior MA-PM (r=0.96 and 0.94, respectively, P<0.01 for both). The discrepancy between the anteroposterior diameter of the ring (outside diameter) and that of the native valve was 1.0±2.9

CiNii
In Vivo Assessment of Novel Stentless Valve in the Mitral Position

Kainuma Satoshi, Kasegawa Hitoshi, Miyagawa Shigeru, Nishi Hiroyuki, Yaku Hitoshi, Takanashi Shuichiro, Hashimoto Kazuhiro, Okada Yukikatsu, Nakatani Satoshi, Umezu Mitsuo, Daimon Takashi, Sakaguchi Taichi, Toda Koichi, Sawa Yoshiki, on behalf of, the, Committee of the, Japanese, Society of, Stentless Mitral Valve

JAPANESE CIRCULATION JOURNAL 79 ( 3 ) 553 - 559 2015

　View Summary

Background:We conducted in vivo examinations of a newly designed stentless mitral valve (SMV), formed by suturing 2 leaflets with the "legs" serving as chorda tendinea, made from bovine pericardium, to a flexible ring.Methods and Results:Seven pigs underwent implantation of the SMV constructed with a 23-mm (n=5) or 25-mm (n=2) Duran ring. Baseline echocardiography examinations were used to evaluate the annular anteroposterior diameter, and distance between the mitral annulus (MA) and papillary muscles (PMs) to determine SMV-leg length. After removing the native valve, the SMV-legs were fixed to the anterior and posterior PMs, followed by fixation of the ring to the native MA. Immediately after surgery, all animals presented none or trivial mitral regurgitation, with mean and peak trans-SMV pressure gradient values of 1.9±0.8 and 6.0±3.1 mmHg, respectively. The mean length of the SMV-leg was 19.4±3.9 mm, which correlated with the distance between anterior and posterior MA-PM (r=0.96 and 0.94, respectively, P<0.01 for both). The discrepancy between the anteroposterior diameter of the ring (outside diameter) and that of the native valve was 1.0±2.9

CiNii
True Engineering–Medical Collaboration on Vascular Surgery

Umezu Mitsuo

Jpn. J. Vasc. Surg. 0 ( 0 ) 2015

　View Summary

In this seminar, I discuss three types of applied research in which collaborations between biomedical engineers and medical doctors can advance the surgical field of vascular grafting. First, I describe a mock circulatory system designed to simulate regional hemodynamics and input impedance in the human aorta. This circuit can estimate the cardiac work that results from implanting or replacing a synthetic aortic graft. Simulation shows that replacement of an aortic graft made of silicone rubber with one made of polytetrafluoroethylene (PTFE) increases cardiac work significantly. Second, I show how technology originally developed for neurosurgical navigation can be applied to the replacement of a thoraco-abdominal aortic aneurysm with a PTFE graft. Here, a registration method combines visual relationships between the real operative space and a three-dimensional space constructed from images obtained by computed tomography. The system employs a phantom thoraco-abdominal artery to accurately locate the Adamkiewicz artery that often, but not always, arises from a left inferior intercostal artery. To date, this navigation system has contributed to the surgical success of eighty-six aortic grafts. Third, I introduce a computational fluid dynamic (CFD) program to predict the distribution of blood flow in a three-branch graft during thoracic endovascular aortic repair (TEVAR). Phase-contrast magnetic resonance angiography image (PC-MRI) of the blood flow distribution determines the initial conditions in patients and healthy individuals. Calculations show a permissible 3% decrease in flow in the descending aorta after surgical endovascular debranching. Finally, I emphasize the importance of educating and training new leaders of Medical Regulatory Science to achieve a true engineering-medical collaboration at Tokyo Women's and Waseda University Joint Institution for Advances Biomedical Sciences.

CiNii
Novel 3D in vitro model for evaluating vascular permeability

FUJISAWA Kanoko, MATSUDA Isamu, SUEHIRO Junichi, YUKAWA Yasuhiro, UMEZU Mitsuo, MATSUNAGA.T Yukiko

SEISAN KENKYU 67 ( 3 ) 255 - 257 2015

　View Summary

Increased vascular permeability is a hallmark of inflammation accompanying tumor progression and diabetic retinopathy. For applying to anti-inflammatory drug testing and screening, we have newly developed an in vitro 3D microvasculature model to evaluate vascular permeability. In this model, we could measure and calculate extravasation pattern of FITCdextran fluorescence and determine endothelial barrier changes in response to thrombin, a known pro-inflammatory protease.

DOI CiNii
2A14 Investigation of a relationship between hemodynamics and initiation of cerebral aneurysms : CFD analysis using an aneurysmal removal

Murayoshi Takuma, Tobe Yasutaka, Sugiura Takuma, Yagi Takanobu, Umezu Mitsuo, Hayashi Yoshifumi, Yoshida Hirotaka, Nishitani Kazutoshi, Okada Yoshifumi, Kitahara Shigemi

2015 ( 27 ) 307 - 308 2015.01

CiNii
2A12 Comparison of hemodynamics and infrastructure of human cerebral aneurysms

Tobe Yasutaka, Yagi Takanobu, Kawamura Koichi, Sugiura Takuma, Umezu Mitsuo, Hayashi Yoshifumi, Yoshida Hirotaka, Nishitani Kazutoshi, Okada Yoshifumi, Kitahara Shigemi

2015 ( 27 ) 303 - 304 2015.01

CiNii
2E33 Improvement of usability of navigation system for the treatment of aortic aneurysm by vascular prosthesis

TAKAHASHI Yasuhiro, UEMATSU Miyuki, AOMI Shigeyuki, IIMURA Hiroshi, NAKAOKA Ryusuke, NIIMI Shingo, SUZUKI Takashi, MURAGAKI Yoshihiro, ISEKI Hiroshi, UMEZU Mitsuo, IWASAKI Kiyotaka

2015 ( 27 ) 505 - 506 2015.01

CiNii
2A35 Study on relationship between minimum horizontal cross-sectional area at anastomosis and energy loss for development of anastomosis assessment feedback system

OYAMA Daisuke, PARK Young Kwang, YAGI Takanobu, IWASAKI Kiyotaka, OSAKA Shinichi, UMEZU Mitsuo

2015 ( 27 ) 329 - 330 2015.01

CiNii
2A33 Study on an adaptation of hemodynamics before and after cerebrovascular bypass surgery

TAKAMURA Kenji, UMEZU Mitsuo, YAGI Takanobu, WATANABE Mikihiko, KATAOKA Hiroharu, YAMAMOTO Akihide, IGUCHI Satoshi, Iida Hidehiro, NUMATA Naoki, NAKAMURA Masanori

The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2015 ( 0 ) 325 - 326 2015 [Refereed]

DOI CiNii
2A11 Study of relationship between hemodynamics and mural cells in thinning and thickening wall of human unruptured cerebral aneurysms

Sugiura Takuma, Yagi Takanobu, Kawamura Koichi, Tobe Yasutaka, Umezu Mitsuo, Hayashi Yoshifumi, Yoshida Hirotaka, Nishitani Kazutoshi, Okada Yoshifumi, Kitahara Shigemi

2015 ( 27 ) 301 - 302 2015.01

CiNii
1E26 Development of a novel 5-DOF chuck for tensile test of anterior cruciate ligament

SAITO Shumpei, IWASAKI Kiyotaka, IMASU Hiroki, TAKANO Kazuya, UMEZU Mitsuo

2015 ( 27 ) 197 - 198 2015.01

CiNii
1D44 Investigation of hemoglobin leakage imaging using chemiluminescence

UMETANI Kotaro, YAGI Takanobu, NAKAMURA Masanori, TEZUKA Ryo, UMEZU Mitsuo

2015 ( 27 ) 173 - 174 2015.01

CiNii
1D14 A proposal of evaluation criteria for anti-thrombogenicity of slow continuous hemofiltration devices

HIRATA Mayuki, IWASAKI Kiyotaka, MATSUHASHI Yuki, TAKAHASHI Azuma, NAGAI Mirei, UMEZU Mitsuo

2015 ( 27 ) 141 - 142 2015.01

CiNii
1D13 Development of compact thrombogenicity test circuit for the coronary stent

MATSUHASHI Yuki, IWASAKI Kiyotaka, TAKAHASHI Azuma, HIRATA Mayuki, YAMAMOTO Yoshiki, SUZUKI Sara, UMEZU Mitsuo

2015 ( 27 ) 139 - 140 2015.01

CiNii
1D12 Comparison of hemolytic property of two different pressure-loss oxygenators using the novel hemolysis test circuit

TAKAHASHI Azuma, IWASAKI Kiyotaka, MATSUHASHI Yuki, HIRATA Mayuki, YAMAMOTO Yoshiki, SUZUKI Sara, UMEZU Mitsuo

2015 ( 27 ) 137 - 138 2015.01

CiNii
1B43 Assessment of in vitro performance of a stentless mitral valve (Normo valve) using a pulsatile circulation system

HORIUCHI Yuki, IWASAKI Kiyotaka, MOON Sojung, KANAYA Kohei, UMEZU Mitsuo

2015 ( 27 ) 89 - 90 2015.01

CiNii
1B42 Development of a pulsatile flow simulator for the assessment of proper deployment of fenestrated stent grafts

ASATO Kenya, UEMATSU Miyuki, TANAKA Yoshinori, TAKAHASHI Yasuhiro, AZUMA Takashi, YAMAZAKI Kenji, NAKAOKA Ryusuke, NIIMI Shingo, UMEZU Mitsuo, IWASAKI Kiyotaka

2015 ( 27 ) 87 - 88 2015.01

CiNii
Induced Pluripotent Stem Cell Differentiation under Constant Shear Stress

N. K. Mohd Zin, K. Sakaguchi, Y. Haraguchi, T. Yagi, K. Masuura, T. Shimizu, M. Umezu

7TH WACBE WORLD CONGRESS ON BIOENGINEERING 2015 52 7 - 10 2015

　View Summary

Mechanotransduction in in-vitro studies has yet to be done extensively using human induced pluripotent (hiPS) cells. These external mechanical factors are important controlling factor for cell differentiation at a cellular level particularly in cardiomyocytes cells. Cells in a living body are being exposed to many kind of stresses; shear stress in particular modulates cellular function in a living body. Similarly, we are trying to understand the link between the shear stress in the bioreactor and the differentiation effects it has on iPS cells. In this study, we investigate the difference of strictly uniform laminar shear stress with a non-uniform laminar flow and its effects on the cell survival rate and differentiation. Additionally, the elimination of biochemical factors were done to satisfy the need of demand for clinically usable cells for the near future use. By eliminating cytokine induced differentiation. In addition, information pertaining to relationship between fluid shear stress, cellular deformations, cell differentiation and cell survival rate could provide a more optimised condition for cultivation specific type of cells within a shorter time period.

DOI

Scopus
Induced Pluripotent Stem Cell Differentiation under Constant Shear Stress

N. K. Mohd Zin, K. Sakaguchi, Y. Haraguchi, T. Yagi, K. Masuura, T. Shimizu, M. Umezu

7TH WACBE WORLD CONGRESS ON BIOENGINEERING 2015 52 7 - 10 2015 [Refereed]

　View Summary

Mechanotransduction in in-vitro studies has yet to be done extensively using human induced pluripotent (hiPS) cells. These external mechanical factors are important controlling factor for cell differentiation at a cellular level particularly in cardiomyocytes cells. Cells in a living body are being exposed to many kind of stresses; shear stress in particular modulates cellular function in a living body. Similarly, we are trying to understand the link between the shear stress in the bioreactor and the differentiation effects it has on iPS cells. In this study, we investigate the difference of strictly uniform laminar shear stress with a non-uniform laminar flow and its effects on the cell survival rate and differentiation. Additionally, the elimination of biochemical factors were done to satisfy the need of demand for clinically usable cells for the near future use. By eliminating cytokine induced differentiation. In addition, information pertaining to relationship between fluid shear stress, cellular deformations, cell differentiation and cell survival rate could provide a more optimised condition for cultivation specific type of cells within a shorter time period.

DOI

Scopus
In vivo assessment of novel stentless valve in the mitral position.

Satoshi Kainuma, Hitoshi Kasegawa, Shigeru Miyagawa, Hiroyuki Nishi, Hitoshi Yaku, Shuichiro Takanashi, Kazuhiro Hashimoto, Yukikatsu Okada, Satoshi Nakatani, Mitsuo Umezu, Takashi Daimon, Taichi Sakaguchi, Koichi Toda, Yoshiki Sawa

Circulation journal : official journal of the Japanese Circulation Society 79 ( 3 ) 553 - 9 2015 [Refereed] [Domestic journal]

　View Summary

BACKGROUND: We conducted in vivo examinations of a newly designed stentless mitral valve (SMV), formed by suturing 2 leaflets with the "legs" serving as chorda tendinea, made from bovine pericardium, to a flexible ring. METHODS AND RESULTS: Seven pigs underwent implantation of the SMV constructed with a 23-mm (n=5) or 25-mm (n=2) Duran ring. Baseline echocardiography examinations were used to evaluate the annular anteroposterior diameter, and distance between the mitral annulus (MA) and papillary muscles (PMs) to determine SMV-leg length. After removing the native valve, the SMV-legs were fixed to the anterior and posterior PMs, followed by fixation of the ring to the native MA. Immediately after surgery, all animals presented none or trivial mitral regurgitation, with mean and peak trans-SMV pressure gradient values of 1.9±0.8 and 6.0±3.1 mmHg, respectively. The mean length of the SMV-leg was 19.4±3.9 mm, which correlated with the distance between anterior and posterior MA-PM (r=0.96 and 0.94, respectively, P<0.01 for both). The discrepancy between the anteroposterior diameter of the ring (outside diameter) and that of the native valve was 1.0±2.9 mm, which correlated with the trans-SMV pressure gradient (r=0.81, P=0.025). CONCLUSIONS: In our preliminary study, the SMV demonstrated excellent diastolic inflow dynamics and closing function in vivo. Preoperative precise assessment of MV configuration may serve as a basis for selection of appropriate ring size and SMV-leg length.

DOI PubMed

Scopus

4

Citation

(Scopus)
Functional analysis of the transcription factors specifically expressed in hematopoietic stem cells

S Kozakai, T Umemoto, M Yamato, M Umezu, T Okano

The 2014 ascb/ifcb meeting 2014.12 [Refereed]
Construction of three-dimensional vascularized cardiac tissue with cell sheet engineering

Katsuhisa Sakaguchi, Tatsuya Shimizu, Teruo Okano

Journal of controlled release corel-07482 2014.12
Simultaneous comparison of thrombogenic reactions to different combinations of anticoagulants, activated clotting times, and materials

Mirei Nagai, Kiyotaka Iwasaki, Mitsuo Umezu, Makoto Ozaki

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS 102 ( 8 ) 1605 - 1612 2014.11 [Refereed]

　View Summary

Thrombogenic reactions under multiple interactions of pharmacological agents, doses, and materials have not been well understood yet. The aim of this study was to investigate the ability to simultaneously compare thrombogenic reactions to different combinations of anticoagulants, doses, and blood-contacting materials, in a single human blood using an in vitro test method. Four venous blood samples were drawn from each of six healthy volunteers into syringes that contained two different amounts of heparin and argatroban to set the activated clotting time (ACT) to approximately 200 or 500 s, respectively. The four blood samples from each volunteer were immediately poured into two clinical-grade extracorporeal circulation tubes: a polyvinyl chloride (PVC) tube and a poly(2-methoxyethyl acrylate)-coated (PMEA) PVC tube. These tubes with an inner diameter of 12.7 mm were rotated at 183 rpm in a 37 degrees C chamber for 10 min. The results indicated that the in vitro thrombogenicity test method was capable of assessing differences in platelet factor 4 and beta-thromboglobulin increases among different combinations of the two materials, two anticoagulants, and two ACTs. Higher amounts of total plasma proteins were absorbed on PVC tubes than on PMEA-coated tubes when using the same anticoagulant and dose. These data elucidate that the in vitro thrombogenicity test method is useful for the simultaneous quantitative evaluation of the influences of various combinations of materials, pharmacological agents, and doses on thrombogenicity in a single human blood. (C) 2014 Wiley Periodicals, Inc.

DOI

Scopus

1

Citation

(Scopus)
Construction of tissue model with microcirculation for pharmaceutical testing,7th world congress on preventive and regenerative medicine,

Yuki SATO, Katsuhisa SAKAGUCHI, Tatsuya SHIMIZU, Mitsuo UMEZU, Teruo OKANO

7th world congress on preventive and regenerative medicine program ( S30-2 ) 2014.11
Low temperature perfusion culture for preparing three-dimensional myocardial tissue,

Kana Matsuura, Katsuhisa Sakaguchi, Tatsuya Shimizu, Mitsuo Umezu, Teruo Okano

7th world congress on preventive and regenerative medicine, 7th world congress on preventive and regenerative medicine program ( S29-3 ) 2014.11
有限要素法を用いた繰り返し屈曲変形が冠動脈ステントの破断におよぼす影響の検討

朱暁冬, 岩崎清隆, 得武祐諭, 梅津光生

,第25回バイオフロンティア講演会プログラム, ( c109 ) 2014.10
自己拡張型Ni-Ti合金製ステントを留置した浅大腿動脈の応用解析:

徳武祐諭, 岩崎清隆, 朱暁冬, 梅津光生

,第25回バイオフロンティア講演会プログラム日本機械学会若手優秀講演フェロー賞 ( c110 ) 2014.10
Expression of microRNA-1, microRNA-133a and Hand2 protein in cultured embryonic rat cardiomyocytes

Zhonggang Feng, Rie Takahashi, Takao Nakamura, Daisuke Sato, Nobuyuki Shirasawa, Ayako Nakayama, Sakura Kurashige, Tadashi Kosawada, Tatsuo Kitajima, Mitsuo Umezu

IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY-ANIMAL 50 ( 8 ) 700 - 706 2014.09 [Refereed]

　View Summary

In this study, we investigated the expression of the pathway, SRF-microRNA-1/microRNA-133a-Hand2, in the Wistar rat embryonic ventricular cardiomyocytes under conventional monolayer culture. The morphological observation of the cultured cardiomyocytes and the mRNA expression levels of three vital constituent proteins, MLC-2v, N-cadherin, and connexin43, demonstrated the immaturity of these cultured cells, which was featured by less myofibril density, immature sarcomeric structure, and significantly lower mRNA expression of the three constituent proteins than those in neonatal ventricular samples. More importantly, results in this study suggest that the change of SRF-microRNA-1/microRNA-133a-Hand2 pathway results into the attenuation of the Hand2 repression in cultured cardiomyocytes. These outcomes are valuable to understand the cellular state as embryonic cardiomyocytes to be in vitro model and might be useful for the assessment of engineered cardiac tissue and cardiac differentiation of stem cells.

DOI

Scopus

8

Citation

(Scopus)
The mechanisms of fibroblast-mediated compaction of collagen gels and the mechanical niche around individual fibroblasts

Zhonggang Feng, Yusuke Wagatsuma, Masato Kikuchi, Tadashi Kosawada, Takao Nakamura, Daisuke Sato, Nobuyuki Shirasawa, Tatsuo Kitajima, Mitsuo Umezu

BIOMATERIALS 35 ( 28 ) 8078 - 8091 2014.09 [Refereed]

　View Summary

Fibroblast-mediated compaction of collagen gels attracts extensive attention in studies of wound healing, cellular fate processes, and regenerative medicine. However, the underlying mechanism and the cellular mechanical niche still remain obscure. This study examines the mechanical behaviour of collagen fibrils during the process of compaction from an alternative perspective on the primary mechanical interaction, providing a new viewpoint on the behaviour of populated fibroblasts. We classify the collagen fibrils into three types bent, stretched, and adherent and deduce the respective equations governing the mechanical behaviour of each type; in particular, from a putative principle based on the stationary state of the instantaneous Hamiltonian of the mechanotransduction system, we originally quantify the stretching force exerted on each stretched fibrils. Via careful verification of a structural elementary model based on this classification, we demonstrate a clear physical picture of the compaction process, quantitatively elucidate the panorama of the micro mechanical niche and reveal an intrinsic biphasic relationship between cellular traction force and matrix elasticity. Our results also infer the underlying mechanism of tensional homoeostasis and stress shielding of fibroblasts. With this study, and sequel investigations on the putative principle proposed herein, we anticipate a refocus of the research on cellular mechanobiology, in vitro and in vivo. (C) 2014 Elsevier Ltd. All rights reserved.

DOI

Scopus

31

Citation

(Scopus)
適応外ステントを使用し治療した頭蓋ない動脈狭窄症の安全性および妥当性

山家弘雄, 林宣秀, 三木潤一郎, 仲寛, 梅津光生, 岩崎清隆

第8回医療機器に関するレギュラトリーサイエンス研究会(RS研究会),プログラム・抄録集 4 2014.09
心臓植込み型電気的デバイスの医療機関からの説明に対する患者の意見の調査

青木郁香, 岩崎清隆, 梅津光生, 笠貫宏

第8回医療機器に関するレギュラトリーサイエンス研究会(RS研究会),プログラム・抄録集 8 2014.09
カプセル内視鏡を事例にした市販前後の有効性のデータ分析に関する検討

飯嶋一雄, 梅津光生, 岩崎清隆

第8回医療機器に関するレギュラトリーサイエンス研究会(RS研究会),プログラム・抄録集 10 2014.09
医療レギュラトリーサイエンスの共同大学院開設5年目の実績と評価,

軽部裕代, 伊関洋, 岩崎清隆, 武岡真司, 池田康夫, 笠貫宏, 有賀淳, 飯室聡, 正宗賢, 大和雅之, 渡辺夏巳

第8回医療機器に関するレギュラトリーサイエンス研究会(RS研究会),プログラム・抄録集, 11 2014.09
繰り返し屈曲変形の角度変化量が冠動脈ステントの破断に及ぼす影響の有限要素法解析,

朱暁冬, 岩崎清隆, 徳武祐諭, 梅津光生

生活生命支援医療福祉工学系学会連合大会2014(LIFE2014)若手プレゼンテーション賞受賞 2014.09
生体情報モニタのアラーム発生状況の可視化による不要なアラーム削減への取り組み

越後雅博, 横井宏佳, 鈴木三弥子, 梅津光生

医療の質・安全学会誌 10 ( 1 ) 3 - 40 2014.09
Development of an in vitro thrombogenicity test method for continus hemofiltration devices,

Yuki Matsuhashi, Kiyotaka Iwasaki, Azuma Takahashi, Mayuki Hirata, Mitsuo Umezu

7th world congress of biomechanics,2014.7 (Boston) 2014.07
Investigation of the relationship between hemodynamics and ultrastructure of aneurysm walls in human unruptured cerebral aneurysms using CFD and TEM,

Yasutaka Yobe

7th world congress of biomechanics,2014.7 (Boston) 2014.07
Deveropment of a novel in-vitro thrombogenicity test methodology to clarify the risk of thrombus detachment from inflow cannula of left ventricular assist devices,

A Takahashi, K Iwasaki, Y Matsuhashi, m Hirata, M Nagai, k Yamazaki, M Umezu

7th world congress of biomechanics,2014.7 (Boston) 2014.07
Investigation relationship Between hemodynamics and wall pathology of human unruptured cerebral aneurysms,

T Sugiura, Y Tobe, k Kawamura, t Yagi, Y Iwabuchi, M Yamanashi, K Takamura, M Umezu, Y Hayashi, H Yoshida, K Nishitani, Y Okada, S Kitahara

7th world congress of biomechanics,2014.7 (Boston) 2014.07
冠動脈の屈曲変形を模擬した屈曲負荷環境における冠動脈ステントの応力解析方法の構築,生体医工学

朱暁冬, 岩崎清隆, 新井淳, 大場貴文, 徳武祐諭, 梅津光生

第53回日本生体医工学会大会 52 2014.06
Awareness of electromagnetic interference in patients with cardiac implantable electronic devices: An analysis of hospital explanations and other factors

Fumika AOKI, Kiyotaka IWASAKI, Mitsuo UMEZU, Hiroshi KASANUKI

レギュラトリーサイエンス学会誌 4 ( 2 ) 87 - 102 2014.05
Surgical training technology for cerebrovascular anastomosis

Masakazu Higurashi, Yi Qian, Massimiliano Zecca, Young-Kwang Park, Mitsuo Umezu, Michael Kerin Morgan

JOURNAL OF CLINICAL NEUROSCIENCE 21 ( 4 ) 554 - 558 2014.04 [Refereed]

　View Summary

Cerebrovascular anastomosis (for example in the management of Moyamoya disease or complex aneurysms) is a rarely performed but essential procedure in neurosurgery. Because of the complexity of this technique and the infrequent clinical opportunities to maintain skills relevant to this surgery, laboratory training is important to develop a consistent and competent performance of cerebrovascular anastomosis. We reviewed the literature pertaining to the training practices surrounding cerebrovascular anastomosis in order to understand the ways in which trainees should best develop these skills. A wide variety of training methods have been described. These may be classified into five general categories, according to training materials used, being synthetic material, living animal, animal carcass, human cadaver, and computer simulation. Ideally, a novice begins training with non-biological material. After gaining sufficient dexterity, the trainee will be able to practice using biological materials followed by high fidelity models prior to actual surgery. Unfortunately, the effectiveness of each model has generally, to our knowledge, only been judged subjectively. Objective quantification methods are necessary to accelerate the acquisition of competence. (C) 2013 Elsevier Ltd. All rights reserved.

DOI

Scopus

21

Citation

(Scopus)
低温培養及び培養液潅流可能な血管網導入技術による3次元心筋組織の構築

坂口勝久, 清水達也, 松浦加奈, 日向祐人, 関根秀一, 大和雅之, 梅津光生, 岡野光夫

再生医療増刊号第13回日本再生医療学会総会プログラム・抄録 13 222 2014.03
移植へ向けた動静脈閉鎖系三次元ヒト組織の構築

佐藤祐樹, 坂口勝久, 田中裕也, 清水達也, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

再生医療増刊号第13回日本再生医療学会総会プログラム・抄録 305 2014.03
生体外におけるヒトiPS細胞由来心筋細胞を用いた組織構築

田中裕也, 坂口勝久, 清水達也, 関根秀一, 松浦勝久, 大和雅之, 梅津光生, 岡野光夫

第13回日本再生医療学会総会プログラム・抄録,再生医療増刊号 13 309 2014.03
心臓植え込み型電気的デバイシのリスクに関する医療機関の説明と患者の理解の調査

梅津光生

第7回医療機器に関するレギュラトリーサイエンス研究会,プログラム・抄録集,日本生体医工学学会専門別研究会 2 - 4 2014.03
EVAHEART 脱血管改良による血栓症リスク低減評価のための血栓飛散量評価試験法の開発

岩崎清隆, 高橋東, 松橋祐輝, 平田麻由紀, 永井美玲, 山崎健二, 笠貫宏, 梅津光生

第42回人工心臓と補助循環懇話会学術集会プログラム・抄録集 52 2014.03
目利き人材を育てるための教育・研究環境の整備,

梅津光生, 岩崎清隆, 伊関洋, 軽部裕代, 山崎健二, 笠貫宏

第42回人工心臓と補助循環懇話会学術集会プログラム・抄録集,pp59 59 2014.03
新規In vitro血栓性評価試験法による補助人工心臓の脱血管周囲に形成される血栓の飛散リスク比較評価,第42回人工心臓と補助循環懇話会学術集会プログラム・抄録集,pp138,2014.3(越後湯沢)ベストポスター賞

高橋東, 岩崎清隆, 松橋祐輝, 平田麻由紀, 永井美玲, 山崎健二, 梅津光生

第42回人工心臓と補助循環懇話会学術集会プログラム・抄録集,pp138,2014.3(越後湯沢)ベストポスター賞 138 2014.03
Study on visualization of ventricular assist device development process using system dynamics,

Tsugiko Kato, Yutaka Tsakahashi, Mitsuo Umezu

Asia-Pacific system dynamics conference,1021,2014.2 (Tokyo) 2014.02
The mechanisms of fibroblast-mediated compaction of collagen gels and the mechanical niche around individual fibroblasts.

Feng Zhonggang, Wagatsuma Yusuke, Kikuchi Masato, Kosawada Tadashi, Nakamura Takao, Sato Daisuke, Shirasawa Nobuyuki, Kitajima Tatsuo, Umezu Mitsuo

The mechanisms of fibroblast-mediated compaction of collagen gels and the mechanical niche around individual fibroblasts. 35 ( 28 ) 2014

　View Summary

:Fibroblast-mediated compaction of collagen gels attracts extensive attention in studies of wound healing, cellular fate processes, and regenerative medicine. However, the underlying mechanism and the cellular mechanical niche still remain obscure. This study examines the mechanical behaviour of collagen fibrils during the process of compaction from an alternative perspective on the primary mechanical interaction, providing a new viewpoint on the behaviour of populated fibroblasts. We classify the collagen fibrils into three types - bent, stretched, and adherent - and deduce the respective equations governing the mechanical behaviour of each type; in particular, from a putative principle based on the stationary state of the instantaneous Hamiltonian of the mechanotransduction system, we originally quantify the stretching force exerted on each stretched fibrils. Via careful verification of a structural elementary model based on this classification, we demonstrate a clear physical picture of the compaction process, quantitatively elucidate the panorama of the micro mechanical niche and reveal an intrinsic biphasic relationship between cellular traction force and matrix elasticity. Our results also infer the underlying mechanism of tensional homoeostasis and stress shielding of fibroblasts. With this study, and sequel investigations on the putative principle proposed herein, we anticipate a refocus of the research on cellular mechanobiology, in vitro and in vivo.

DOI

Scopus

31

Citation

(Scopus)
Surgical training technology for cerebrovascular anastomosis.

Higurashi Masakazu, Qian Yi, Zecca Massimiliano, Park Young-Kwang, Umezu Mitsuo, Morgan Michael Kerin

Surgical training technology for cerebrovascular anastomosis. 21 ( 4 ) 2014

　View Summary

:Cerebrovascular anastomosis (for example in the management of Moyamoya disease or complex aneurysms) is a rarely performed but essential procedure in neurosurgery. Because of the complexity of this technique and the infrequent clinical opportunities to maintain skills relevant to this surgery, laboratory training is important to develop a consistent and competent performance of cerebrovascular anastomosis. We reviewed the literature pertaining to the training practices surrounding cerebrovascular anastomosis in order to understand the ways in which trainees should best develop these skills. A wide variety of training methods have been described. These may be classified into five general categories, according to training materials used, being synthetic material, living animal, animal carcass, human cadaver, and computer simulation. Ideally, a novice begins training with non-biological material. After gaining sufficient dexterity, the trainee will be able to practice using biological materials followed by high fidelity models prior to actual surgery. Unfortunately, the effectiveness of each model has generally, to our knowledge, only been judged subjectively. Objective quantification methods are necessary to accelerate the acquisition of competence.

DOI

Scopus

21

Citation

(Scopus)
Orbital Shaking Promoted Vascular Elastogenesis in Cultured Rat Aortic Smooth Muscle Cells

Shiraishi, Ryosuke, Iwasaki, Kiyotaka, Aida, Takashi, Saito, Shumpei, Zin, Nur Khatijah Mohd, Takeoka, Shinji, Umezu, Mitsuo, Minamisawa, Susumu

BIOPHYSICAL JOURNAL 106 ( 2 ) 615A - 615A 2014 [Refereed]
早稲田大学の先進医療‐TWInsからの挑戦

梅津光生

関西稲門経済人の集い2014 2014
Application of the international medical alarm standard in clinical practice

Masahiro ECHIGO, Hiroshi KASEGAWA, Kiyotaka IWASAKI, Mitsuo UMEZU

医薬品医療機器レギュラトリーサイエンス 45 ( 3 ) 232 - 242 2014

CiNii
生体外における循環システムを伴ったヒト三次元組織モデル構築

佐藤祐樹, 坂口勝久, 田中裕也, 清水達也, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

第26回バイオエンジニアリング講演会講演論文集 159 - 160 2014.01
脳動脈瘤の発生初期とされる分岐血管壁の菲薄化と血行動態に関する検討

岩渕祐貴, 八木高伸, 戸部泰貴, 梅津光生, 林祥史, 吉田浩貴, 西谷和敏, 岡田義文, 北原茂実

第26回バイオエンジニアリング講演会講演論文集 209 - 210 2014.01
脳血管バイパス術における術前・術後の血行動態に関する検討,

高村兼司, 八木高伸, 山梨桃子, 片岡大治, 山本明秀, 井口智史, 飯田秀博, 佐藤洸太, 中村匡徳, 梅津光生

第26回バイオエンジニアリング講演会講演論文集 211 - 212 2014.01 [Refereed]
CFD流出境界条件の違いが脳動脈瘤内血流に及ぼす影響の検討

山梨桃子, 八木高伸, 平口心, 三登将平, 高村兼司, 梅津光生, 林祥史, 吉田浩貴, 西谷和敏, 岡田義文, 北原茂実

第26回バイオエンジニアリング講演会講演論文集 219 - 220 2014.01
国産人工弁(ステントレス僧帽弁)の実用化への挑戦

梅津光生, 岩崎清隆, 加瀬川均, 笠貫宏, 澤芳樹, 高梨秀一郎, 夜久均, 田端実

第26回バイオエンジニアリング講演会講演論文集 347 - 348 2014.01
新規In vitro 血栓性評価法による補助人工心臓の平滑及びメッシュ脱血管周囲に形成される血栓の飛散リスク比較評価

岩崎清隆, 高橋東, 松橋祐樹, 平田麻由紀, 永井美玲, 山崎健二, 梅津光生

第26回バイオエンジニアリング講演会講演論文集 349 - 350 2014.01
屈曲負荷型加速耐久試験装置による屈曲角度変化量が冠動脈ステントの破損耐久性に及ぼす影響の検討

新井淳, 岩崎清隆, 朱暁冬, 大場貴文, 徳武祐諭, 山本匡, 挽地裕, 梅津光生

第26回バイオエンジニアリング講演会講演論文集 413 - 414 2014.01
衝撃せん断流によるヒト赤血球破壊に関する検討

岩本理沙, 八木高伸, 梅谷康太郎, 手塚諒, 梅津光生

第26回バイオエンジニアリング講演会講演論文集 431 - 432 2014.01
化学発光を用いた溶血現象の可視化手法の検討

梅谷康太郎, 八木高伸, 中村匡徳, 岩本理沙, 手塚諒, 梅津光生

第26回バイオエンジニアリング講演会講演論文集 433 - 434 2014.01
弾性を有するヒト弓部大動脈瘤モデルを用いた胸部大動脈瘤ステントグラフトない挿術におけるデリバリーシースの走行形状の検討

高橋泰浩, 岩崎清隆, 安里権也, 植松美幸, 中岡竜介, 新見伸吾, 梅津光生

第26回バイオエンジニアリング講演会講演論文集 507 - 508 2014.01
分枝付ヒト弓部大動脈瘤モデルにおける開窓型ステントの3次元的留置過程の計測

安里権也, 岩崎清隆, 高橋泰浩, 植松美幸, 中岡竜介, 新見伸吾, 梅津光生

第26回バイオエンジニアリング講演会講演論文集 509 - 510 2014.01
Use of Computational Fluid Dynamics to Estimate Hemodynamic Effects of Respiration on Hypoplastic Left Heart Syndrome Surgery: Total Cavopulmonary Connection Treatments

Jinlong Liu, Yi Qian, Qi Sun, Jinfen Liu, Mitsuo Umezu

The Scientific world journal 2013Artikle ID 131597 2013.12
下肢血管ステントの破損耐久性評価のための屈曲負荷型耐久試験装置の開発

新井淳, 岩﨑清隆, 朱暁冬, 大場貴文, 徳武祐諭, 山本匡, 挽地裕, 梅津光生

第24回バイオフロンティア講演会講演論文集 73 - 74 2013.11
循環シミュレータを用いた心不全患者への補助人工心臓装着による治療効果の検討

岡田昂大, ムンソジョン, 土居徹哉, 五十嵐利博, 山崎健二, 八木高伸, 岩﨑清隆, 藤本哲男, 梅津光生

第24回バイオフロンティア講演会講演論文集 83 - 84 2013.11
ヒト未破裂脳動脈瘤の瘤壁の菲薄化を術前に検知できる血流の指標化に関する検討

岩渕祐貴, 八木高伸, 戸部泰貴, 梅津光生, 林祥史, 吉田浩貴, 西谷和敏, 岡田義文, 北原茂実

第24回バイオフロンティア講演会講演論文集 85 - 86 2013.11
拍動型補助人工心臓の機械弁の違いが溶血性能に及ぼす影響のin vitro比較評価

松橋祐樹, 岩﨑清隆, 高橋東, 平田麻由紀, 梅津光生

第24回バイオフロンティア講演会講演論文集 99 - 100 2013.11
体循環シミュレータを用いたステントレス僧帽弁の開閉特性に関する検討

真鍋晋, 八木高伸, 岩﨑清隆, 加瀬川均, 梅津光生

第24回バイオフロンティア講演会講演論文集 101 - 102 2013.11
TWIns〜医学部の常識にとらわれない医工学

梅津光生

VAscular Intervention Today 8 ( 2 ) 42 - 43 2013.11
Japanese-made implsntable artificial heart (EVAHEART) true medical-engineerong collaboration towards successful clinical outcome

M Umezu, K Yamazaki, S Yamazaki, K Iwasaki, T kitano, T Tokuno

FULUCOME 2013 Program and Abstract book The 12th International conference on fluid control measurements and visualization 19 - 28 2013.11
Fatigue Fracture of Coronary Stents : Visualization of Fracture Resistance

IWASAKI Kiyotaka, UMEZU Mitsuo

Transactions of Visualization Society of Japan 33 ( 131 ) 139 - 144 2013.10

CiNii
医療機器のアラームに関する日本生体医工学会研究—アラームの評価法-

越後雅博, 横井宏佳, 鈴木三弥子, 岩崎清隆, 梅津光生

第6回医療機器に関するレギュラトリーサイエンス研究会(RS研究会)プログラム・抄録集 A - 1 2013.10
患者の危険行動を予知し、転落を防止するための標準化の研究

大津良司, 伊関洋, 梅津光生

第6回医療機器に関するレギュラトリーサイエンス研究会(RS研究会)プログラム・抄録集 A - 4 2013.10
弁関連製品のシミュレータ評価の活用状況に関する研究

北奈央子, 岩崎清隆, 梅津光生

第6回医療機器に関するレギュラトリーサイエンス研究会(RS研究会)プログラム・抄録集 B - 1 2013.10
人工心臓の開発とリスクマネージメント

梅津光生, 岩崎清隆, 笠貫宏, 山崎健二

医工学を知る 82 - 89 2013.10
冠動脈ステントの疲労破壊:破損耐久性の可視化

岩﨑清隆, 梅津光生

可視化情報学会誌 33 ( 131 ) 19 - 24 2013.10
Engineering-based medicine: Anew way to collaborate

Mitsuo Umezu, Kiyotaka Iwasaki, Takanobu Yagi, Young Park, Katsuhisa Sakaguchi, Robert Shiurba, Hiroshi Kasanuki

The 2013 Hirosaki University International Symposium 13 - 18 2013.09
Engineering based medicine

Mitsuo Umezu, Kiyotaka Iwasaki, Takanobu Yagi, Youg Kwang Park, Hiroshi Kasegawa

人工臓器,vol.42 no.2, ppEL2, 第51回日本人工臓器学会大会/第5回国際人工臓器学術大会 42 ( 2 ) EL2 2013.09
医療機器の実用化と安全な普及促進のための非臨床評価法の進展

岩崎清隆, 梅津光生, 笠貫宏

人工臓器,vol.42 no.2, pp WS(H1)-3, 第51回日本人工臓器学会大会/第5回国際人工臓器学術大会 2013.09
赤血球の伸長に応じた衝突・破壊特性

八木高伸, 岩本理沙, 梅谷康太郎, 手塚諒, 梅津光生

人工臓器,vol.42 no.2, pp WS(H3)-4, 第51回日本人工臓器学会大会/第5回国際人工臓器学術大会 2013.09
3分岐人工血管の非臨床試験における血流配分評価法の検討

木浦千夏子, 八木高伸, 中村匡徳, 岩崎清隆, 銭逸, 奥田茂男, 吉武明弘, 志水秀行, 四津良平, 梅津光生

人工臓器,vol.42 no.2, pp OJ-35, 第51回日本人工臓器学会大会/第5回国際人工臓器学術大会 2013.09
Nonlinear mechanical characteristics of soft tissue equivalent,

Zhonggang Feng, Takao Nakamura, Daisuke Sato, Tatsuo Kitajima, Mitsuo Umezu

人工臓器,vol.42 no.2, pp OE-35, 第51回日本人工臓器学会大会/第5回国際人工臓器学術大会 2013.09
ニプロ製国循型臨床用補助人工心臓ポンプのダイアフラム挙動の数値解析第2報:臨床におけるポンプ駆動条件の工学的検証

伊藤一彦, 五十嵐利博, 藤本哲男, 立田良太, 土居徹哉, 岡本吉弘, 田中隆,銭逸, 岩崎清隆, Robert Shiurba, 梅津光生

医工学治療 25 ( 2 ) 85 - 91 2013.09
Combined analysis of pathology and hemodynamics of human unruptured cerebral aneurysm with thin-walled region

Yasutaka Tobe, Takanobu Yagi, Yuki Iwabuchi, Momoko Yamanashi, Kenji Takamura, Kiyotaka Iwasaki, Mitsuo Umezu, Yoshifumo Hayashi, Hirotaka Yoshida, Kazutoshi Nishitani, Yoshifumi Okada, MIchihito Sugawara, Shin Hiraguchi, Toshiro Kubo, Shigemi Kitahara, Atsushi Nakajima

ASME 2013 Summer bioengineering conference 10-1-1, 2013.06 [Refereed]
In-vitro hemodynamic assessment of newly developed stentless mitral valve (NORMO valve)

Susumu Manabe, Hitoshi Kasegawa, Moon Sojung, Takahiro Okada, Tetsuo Doi, Kiyotaka Iwasaki, Tetsuo Fujimoto, Mitsuo Umezu, Hirokuni Arai

13 ISMICS annual scientific meeting 55 2013.06
Numerical analysis of blood flow distribution in 4-and 3-branch vascular grafts

Chikako Konoura, Takanobu Yagi, Masanori Nakamura, Kiyotaka Iwasaki, Yi Qian, Shigeo Okuda, Akihiro Yoshitake, Hideyuki Shimizu, Ryohei Yozu, Mitsuo Umezu

JOURNAL OF ARTIFICIAL ORGANS 16 ( 2 ) 157 - 163 2013.06 [Refereed]

　View Summary

Trifurcated arch grafts (3-branch grafts) are now being used to repair the thoracic aorta in addition to conventional arch grafts (4-branch grafts). The anatomical shape of the 3-branch graft is different from the original vessel, so it is necessary for clinical application to evaluate blood flow distribution in the graft to assess whether there is adequate blood flow to the target organs. To achieve this, we developed a computational fluid dynamics (CFD) method to evaluate blood flow distribution in the grafts. Aortic blood flow was measured by phase-contrast magnetic resonance imaging (PC-MRI), and flow distribution into the branched vessels was obtained. The MRI image was used to create a patient-specific image model that represents the geometry of the aortic arch. The CFD analysis method was employed to determine a boundary condition of the blood flow analysis in the aorta using a patient-specific image model. We also created simplified models of 4-branch and 3-branch grafts and used our CFD analysis method to compare blood flow distribution among simplified models. It was found that blood flow distribution in the descending aorta was 71.3 % for the 4-branch graft and 67.7 % for the 3-branch graft, indicating that a sum of branching flow in the 3-branch graft was almost the same as the one in the 4-branch graft. Therefore, there is no major concern about implanting a new 3-branch graft. Our CFD analysis method may be applied to estimate blood flow distribution of a newly developed vascular graft prior to its clinical use and provide useful information for safe use of the graft.

DOI

Scopus

6

Citation

(Scopus)
Preliminary study on the development of a system dynamics model: The case of EVAHEART

Tsugiko Kato, Mitsuo Umezu, Kiyotaka Iwasaki, Hiroshi Kasanuki, Yutaka Takahashi

Journal of Artificial Organs 16 ( 2 ) 242 - 247 2013.06

　View Summary

The Japanese medical device industry's stagnation over the years can be attributed to the uncertainty related to device development. The purpose of this study is to identify the major factors that impact development. We studied the ventricular assist device EVAHEART through interviews with the persons involved and created a development model using system dynamics. There are at least six stages in the device development process, including interactions with academia and the government. Through a simulation and comparison to Novacor, it was determined that the satisfaction of academia leads to government action in the subsequent measures. Our trial simulation of EVAHEART suggests that it has the potential to clarify unclear relationships in the development of devices. © 2013 The Japanese Society for Artificial Organs.

DOI PubMed

Scopus

3

Citation

(Scopus)
Proposition of an outflow boundary approach for carotid artery stenosis CFD simulation

Yu Zhang, Toyoki Furusawa, Sheau Fung Sia, Mitsuo Umezu, Yi Qian

COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING 16 ( 5 ) 488 - 494 2013.05 [Refereed]

　View Summary

The purpose of this study was to propose an innovative approach of setting outlet boundary conditions for the computational fluid dynamics (CFD) simulation of human common carotid arteries (CCAs) bifurcation based on the concept of energy loss minimisation at flow bifurcation. Comparisons between this new approach and previously reported boundary conditions were also made. The results showed that CFD simulation based on the proposed boundary conditions gave an accurate prediction of the critical stenosis ratio of carotid arteries (at around 65%). Other boundary conditions, such as the constant external pressure (P=0) and constant outflow ratio, either overestimated or underestimated the critical stenosis ratio of carotid arteries. The patient-specific simulation results furthermore indicated that the calculated internal carotid artery flow ratio at CCA bifurcation (61%) coincided with the result obtained by clinical measurements through the use of Colour Doppler ultrasound.

DOI

Scopus

21

Citation

(Scopus)
Experimental insights into flow impingement in cerebral aneurysm by stereoscopic particle image velocimetry: transition from a laminar regime

Takanobu Yagi, Ayaka Sato, Manabu Shinke, Sara Takahashi, Yasutaka Tobe, Hiroyuki Takao, Yuichi Murayama, Mitsuo Umezu

JOURNAL OF THE ROYAL SOCIETY INTERFACE 10 ( 82 ) 2013.05 [Refereed]

　View Summary

This study experimentally investigated the instability of flow impingement in a cerebral aneurysm, which was speculated to promote the degradation of aneurysmal wall. A patient-specific, full-scale and elastic-wall replica of cerebral artery was fabricated from transparent silicone rubber. The geometry of the aneurysm corresponded to that found at 9 days before rupture. The flow in a replica was analysed by quantitative flow visualization (stereoscopic particle image velocimetry) in a three-dimensional, high-resolution and time-resolved manner. The mid-systolic and late-diastolic flows with a Reynolds number of 450 and 230 were compared. The temporal and spatial variations of near-wall velocity at flow impingement delineated its inherent instability at a low Reynolds number. Wall shear stress (WSS) at that site exhibited a combination of temporal fluctuation and spatial divergence. The frequency range of fluctuation was found to exceed significantly that of the heart rate. The high-frequency-fluctuating WSS appeared only during mid-systole and disappeared during late diastole. These results suggested that the flow impingement induced a transition from a laminar regime. This study demonstrated that the hydrodynamic instability of shear layer could not be neglected even at a low Reynolds number. No assumption was found to justify treating the aneurysmal haemodynamics as a fully viscous laminar flow.

DOI

Scopus

58

Citation

(Scopus)
A proposal for redesigning aortofemoral prosthetic Y graft for treating abdominal aortic aneurysms

Tetsuo Fujimoto, Hiroshi Iwamura, Yasuyuki Shiraishi, Tomoyuki Yambe, Kiyotaka Iwasaki, Mitsuo Umezu

Aortic Aneurysm recent advances 195 - 211 2013.05
立体臓器構築を目指した心筋シートによるチューブ状心筋組織の作製

鶴山晋平, 坂口勝久, 清水達也, 関根秀一, 青木信奈子, 松浦勝久, 梅津光生, 岡野光夫

再生医療第12回日本再生医療学会総会プログラム・抄録増刊号 150 2013.03
潅流培養バイオリアクタを用いた血管網付きヒト心筋組織の構築

中山悠衣, 清水達也, 坂口勝久, 加川友己, 松浦勝久, 常田聡, 梅津光生, 岡野光夫

再生医療増刊号第12回日本再生医療学会総会プログラム・抄録 150 2013.03
細胞シートを用いた3次元組織の構築

坂口勝久, 清水達也

幹細胞医療の実用化技術と産業展望シエムシー出版 149 - 153 2013.03
Engineering of vascularized three-dimensional tissue

Katsuhisa Sakaguchi, Tatsuya Shimizu, Masayuki Yamato, Mitsuo Umezu, Teruo

International Journal of Tissue Regeneration 4 ( 1 ) 1 - 6 2013.03
In vitro engineering of vascularized tissue surrogates

Katsuhisa Sakaguchi, Tatsuya Shimizu, Shigeto Horaguchi, Hidekazu Sekine, Masayuki Yamato, Mitsuo Umezu, Teruo Okano

Scientific Reports 1 - 7 2013.02 [Refereed]

DOI

Scopus

252

Citation

(Scopus)
Numerical analysis of blood flow distribution in 4- and 3-branch vascular grafts.

Konoura Chikako, Yagi Takanobu, Nakamura Masanori, Iwasaki Kiyotaka, Qian Yi, Okuda Shigeo, Yoshitake Akihiro, Shimizu Hideyuki, Yozu Ryohei, Umezu Mitsuo

Numerical analysis of blood flow distribution in 4- and 3-branch vascular grafts. 16 ( 2 ) 2013

　View Summary

:Trifurcated arch grafts (3-branch grafts) are now being used to repair the thoracic aorta in addition to conventional arch grafts (4-branch grafts). The anatomical shape of the 3-branch graft is different from the original vessel, so it is necessary for clinical application to evaluate blood flow distribution in the graft to assess whether there is adequate blood flow to the target organs. To achieve this, we developed a computational fluid dynamics (CFD) method to evaluate blood flow distribution in the grafts. Aortic blood flow was measured by phase-contrast magnetic resonance imaging (PC-MRI), and flow distribution into the branched vessels was obtained. The MRI image was used to create a patient-specific image model that represents the geometry of the aortic arch. The CFD analysis method was employed to determine a boundary condition of the blood flow analysis in the aorta using a patient-specific image model. We also created simplified models of 4-branch and 3-branch grafts and used our CFD analysis method to compare blood flow distribution among simplified models. It was found that blood flow distribution in the descending aorta was 71.3 % for the 4-branch graft and 67.7 % for the 3-branch graft, indicating that a sum of branching flow in the 3-branch graft was almost the same as the one in the 4-branch graft. Therefore, there is no major concern about implanting a new 3-branch graft. Our CFD analysis method may be applied to estimate blood flow distribution of a newly developed vascular graft prior to its clinical use and provide useful information for safe use of the graft.

DOI

Scopus

6

Citation

(Scopus)
Experimental insights into flow impingement in cerebral aneurysm by stereoscopic particle image velocimetry: transition from a laminar regime.

Yagi Takanobu, Sato Ayaka, Shinke Manabu, Takahashi Sara, Tobe Yasutaka, Takao Hiroyuki, Murayama Yuichi, Umezu Mitsuo

Experimental insights into flow impingement in cerebral aneurysm by stereoscopic particle image velocimetry: transition from a laminar regime. 10 ( 82 ) 2013

　View Summary

:This study experimentally investigated the instability of flow impingement in a cerebral aneurysm, which was speculated to promote the degradation of aneurysmal wall. A patient-specific, full-scale and elastic-wall replica of cerebral artery was fabricated from transparent silicone rubber. The geometry of the aneurysm corresponded to that found at 9 days before rupture. The flow in a replica was analysed by quantitative flow visualization (stereoscopic particle image velocimetry) in a three-dimensional, high-resolution and time-resolved manner. The mid-systolic and late-diastolic flows with a Reynolds number of 450 and 230 were compared. The temporal and spatial variations of near-wall velocity at flow impingement delineated its inherent instability at a low Reynolds number. Wall shear stress (WSS) at that site exhibited a combination of temporal fluctuation and spatial divergence. The frequency range of fluctuation was found to exceed significantly that of the heart rate. The high-frequency-fluctuating WSS appeared only during mid-systole and disappeared during late diastole. These results suggested that the flow impingement induced a transition from a laminar regime. This study demonstrated that the hydrodynamic instability of shear layer could not be neglected even at a low Reynolds number. No assumption was found to justify treating the aneurysmal haemodynamics as a fully viscous laminar flow.

DOI

Scopus

58

Citation

(Scopus)
In vitro engineering of vascularized tissue surrogates.

Katsuhisa Sakaguchi, Tatsuya Shimizu, Shigeto Horaguchi, Hidekazu Sekine, Masayuki Yamato, Mitsuo Umezu, Teruo Okano

Scientific reports 3 1316 - 1316 2013 [Refereed] [International journal]

　View Summary

In vitro scaling up of bioengineered tissues is known to be limited by diffusion issues, specifically a lack of vasculature. Here, we report a new strategy for preserving cell viability in three-dimensional tissues using cell sheet technology and a perfusion bioreactor having collagen-based microchannels. When triple-layer cardiac cell sheets are incubated within this bioreactor, endothelial cells in the cell sheets migrate to vascularize in the collagen gel, and finally connect with the microchannels. Medium readily flows into the cell sheets through the microchannels and the newly developed capillaries, while the cardiac construct shows simultaneous beating. When additional triple-layer cell sheets are repeatedly layered, new multi-layer construct spontaneously integrates and the resulting construct becomes a vascularized thick tissue. These results confirmed our method to fabricate in vitro vascularized tissue surrogates that overcomes engineered-tissue thickness limitations. The surrogates promise new therapies for damaged organs as well as new in vitro tissue models.

DOI PubMed

Scopus

252

Citation

(Scopus)
Use of Computational Fluid Dynamics to Estimate Hemodynamic Effects of Respiration on Hypoplastic Left Heart Syndrome Surgery: Total Cavopulmonary Connection Treatments

Jinlong Liu, Yi Qian, Qi Sun, Jinfen Liu, Mitsuo Umezu

SCIENTIFIC WORLD JOURNAL 2013Artikle ID 131597 2013 [Refereed]

　View Summary

Total cavopulmonary connection (TCPC), a typical kind of Fontan procedure, is commonly used in the treatment of a functional single ventricle. The palliative cardiothoracic procedure is performed by connecting the superior vena cava and the inferior vena cava to the pulmonary arteries. Due to the difficulty of direct study in vivo, in this paper, computational fluid dynamics (CFD) was introduced to estimate the outcomes of patient-specific TCPC configuration. We mainly focused on the influence of blood pulsation and respiration. Fast Fourier transforms method was employed to separate the measured flow conditions into the rate of breath and heart beat. Blood flow performance around the TCPC connection was investigated by analyzing the results of time-varying energy losses, blood flow distribution rate, local pressure, and wall shear stress distributions. It was found that the value of energy loss including the influence of respiration was 1.5 times higher than the value of energy loss disregarding respiratory influences. The results indicated that the hemodynamic outcomes of TCPC treatment are obviously influenced by respiration. The influence of respiration plays an important role in estimating the results of TCPC treatment and thus should be included as one of the important conditions of computational haemodynamic analysis.

DOI

Scopus

13

Citation

(Scopus)
In vitro fabrication of functional three-dimensional tissues with perfusable blood vessels.

Hidekazu Sekine, Tatsuya Shimizu, Katsuhisa Sakaguchi, Izumi Dobashi, Masanori Wada, Masayuki Yamato, Eiji Kobayashi, Mitsuo Umezu, Teruo Okano

Nature communications 4 1399 - 1399 2013 [Refereed] [International journal]

　View Summary

In vitro fabrication of functional vascularized three-dimensional tissues has been a long-standing objective in the field of tissue engineering. Here we report a technique to engineer cardiac tissues with perfusable blood vessels in vitro. Using resected tissue with a connectable artery and vein as a vascular bed, we overlay triple-layer cardiac cell sheets produced from coculture with endothelial cells, and support the tissue construct with media perfused in a bioreactor. We show that endothelial cells connect to capillaries in the vascular bed and form tubular lumens, creating in vitro perfusable blood vessels in the cardiac cell sheets. Thicker engineered tissues can be produced in vitro by overlaying additional triple-layer cell sheets. The vascularized cardiac tissues beat and can be transplanted with blood vessel anastomoses. This technique may create new opportunities for in vitro tissue engineering and has potential therapeutic applications.

DOI PubMed

Scopus

381

Citation

(Scopus)
In vitro engineering of vascularized tissue surrogates.

Katsuhisa Sakaguchi, Tatsuya Shimizu, Shigeto Horaguchi, Hidekazu Sekine, Masayuki Yamato, Mitsuo Umezu, Teruo Okano

Scientific reports 3 1316 - 1316 2013 [International journal]

　View Summary

In vitro scaling up of bioengineered tissues is known to be limited by diffusion issues, specifically a lack of vasculature. Here, we report a new strategy for preserving cell viability in three-dimensional tissues using cell sheet technology and a perfusion bioreactor having collagen-based microchannels. When triple-layer cardiac cell sheets are incubated within this bioreactor, endothelial cells in the cell sheets migrate to vascularize in the collagen gel, and finally connect with the microchannels. Medium readily flows into the cell sheets through the microchannels and the newly developed capillaries, while the cardiac construct shows simultaneous beating. When additional triple-layer cell sheets are repeatedly layered, new multi-layer construct spontaneously integrates and the resulting construct becomes a vascularized thick tissue. These results confirmed our method to fabricate in vitro vascularized tissue surrogates that overcomes engineered-tissue thickness limitations. The surrogates promise new therapies for damaged organs as well as new in vitro tissue models.

DOI PubMed

Scopus

252

Citation

(Scopus)
Use of computational fluid dynamics to estimate hemodynamic effects of respiration on hypoplastic left heart syndrome surgery: total cavopulmonary connection treatments.

Liu Jinlong, Qian Yi, Sun Qi, Liu Jinfen, Umezu Mitsuo

Use of computational fluid dynamics to estimate hemodynamic effects of respiration on hypoplastic left heart syndrome surgery: total cavopulmonary connection treatments. 2013 2013 [Refereed]

　View Summary

:Total cavopulmonary connection (TCPC), a typical kind of Fontan procedure, is commonly used in the treatment of a functional single ventricle. The palliative cardiothoracic procedure is performed by connecting the superior vena cava and the inferior vena cava to the pulmonary arteries. Due to the difficulty of direct study in vivo, in this paper, computational fluid dynamics (CFD) was introduced to estimate the outcomes of patient-specific TCPC configuration. We mainly focused on the influence of blood pulsation and respiration. Fast Fourier transforms method was employed to separate the measured flow conditions into the rate of breath and heart beat. Blood flow performance around the TCPC connection was investigated by analyzing the results of time-varying energy losses, blood flow distribution rate, local pressure, and wall shear stress distributions. It was found that the value of energy loss including the influence of respiration was 1.5 times higher than the value of energy loss disregarding respiratory influences. The results indicated that the hemodynamic outcomes of TCPC treatment are obviously influenced by respiration. The influence of respiration plays an important role in estimating the results of TCPC treatment and thus should be included as one of the important conditions of computational haemodynamic analysis.

DOI

Scopus

13

Citation

(Scopus)
Clinical Results of Three-Time-Balloon-Inflation Method Performed in Elective PCI Cases

YAMAMOTO Tadashi, IWASAKI Kiyotaka, ARAI Jun, KITAHARA Shigemi, UMEZU Mitsuo

BME 51 ( 6 ) 350 - 356 2013

　View Summary

Percutaneous coronary intervention (PCI) for ischemic heart disease became a common therapy. The improvement of treatment results was caused by invention of drug-eluting stent (DES) but its implantation procedure for pressure and inflation time has not been discussed. 3-time-balloon-inflation method is proved to be an effective method for inflation in in vitro experiments and it was practiced in the clinical field. The purpose of this study is to determine the effectiveness of the 3-time-balloon-inflation method and investigate the factors that cause suppression of stent expansion. From January 2011 to March 2012, PCI with drug-eluting stent (XIENCE V) were performed to 169 patients by a single-operator with 3-time-ballon-inflation method. Minimal lumen area (MLA), vessel cross-sectional area, and plaque cross-section in the MLA were measured by intravascular ultrasound (IVUS) before stent implantation. Minimum stent area (MSA) was measured after stent implantation. Stent expansion ratio (SER) was calculated from assumed area and MSA. Area acquisition ratio (AAR) was calculated from MSA and MLA. Subsequently, the ratio of calcification in the lesion was measured using the color mapping function mounted on the IVUS. The stent diameter used in this study was 2.89±0.35[mm] (mean±SD), stent length was 20.5±6.2[mm] (mean±SD), and the stent expansion pressure was 10.3±2.4[atm] (mean±SD). There was no difference in SER by stent size, target vessels, and MLA. Significant difference was seen in the calcification ratio between the group without pre-dilatation (n=27) and the group with pre-dilatation (n=142), but no difference in SER between the two groups. It was suggested that calcification ratio is one of the factors that causes the suppression of stent expansion because significance of calcification ratio came out in AAR.

CiNii
Fracture Potentials and Dynamic Flexibility of Peripheral Stents: Insights into Clinical Practice From Durability Tests Simulating Multi-loading Environments of Superficial Femoral and Popliteal Arteries

Iwasaki, Kiyotaka, Kishigami, Sho, Arai, Jun, Ohba, Takafumi, Tokutake, Hirotsugu, Zhu Xiaodong, Yagishita, Yuichi, Noguchi, Yusuke, Yamamoto, Tadashi, Hikichi, Yutaka, Umezu, Mitsuo

CIRCULATION 128 ( 22 ) 2013
The proportion of clinically relevant alarms decreases as patient clinical severity decreases in intensive care units: A pilot study

Ryota Inokuchi, Hajime Sato, Yuko Nanjo, Masahiro Echigo, Aoi Tanaka, Takeshi Ishii, Takehiro Matsubara, Kent Doi, Masataka Gunshin, Takahiro Hiruma, Kensuke Nakamura, Kazuaki Shinohara, Yoichi Kitsuta, Susumu Nakajima, Mitsuo Umezu, Naoki Yahagi

BMJ Open 3 ( 9 ) 2013

　View Summary

Objectives: To determine (1) the proportion and number of clinically relevant alarms based on the type of monitoring device
(2) whether patient clinical severity, based on the sequential organ failure assessment (SOFA) score, affects the proportion of clinically relevant alarms and to suggest
(3) methods for reducing clinically irrelevant alarms in an intensive care unit (ICU). Design: A prospective, observational clinical study. Setting: A medical ICU at the University of Tokyo Hospital in Tokyo, Japan. Participants: All patients who were admitted directly to the ICU, aged ≥18 years, and not refused active treatment were registered between January and February 2012. Methods: The alarms, alarm settings, alarm messages, waveforms and video recordings were acquired in real time and saved continuously. All alarms were annotated with respect to technical and clinical validity. Results: 18 ICU patients were monitored. During 2697 patient-monitored hours, 11 591 alarms were annotated. Only 740 (6.4%) alarms were considered to be clinically relevant. The monitoring devices that triggered alarms the most often were the direct measurement of arterial pressure (33.5%), oxygen saturation (24.2%), and electrocardiogram (22.9%). The numbers of relevant alarms were 12.4% (direct measurement of arterial pressure), 2.4% (oxygen saturation) and 5.3% (electrocardiogram). Positive correlations were established between patient clinical severities and the proportion of relevant alarms. The total number of irrelevant alarms could be reduced by 21.4% by evaluating their technical relevance. Conclusions: We demonstrated that (1) the types of devices that alarm the most frequently were direct measurements of arterial pressure, oxygen saturation and ECG, and most of those alarms were not clinically relevant
(2) the proportion of clinically relevant alarms decreased as the patients' status improved and (3) the irrelevance alarms can be considerably reduced by evaluating their technical relevance.

DOI

Scopus

16

Citation

(Scopus)
Prediction of Wall-thinning Area in Unruptured Intracerebral Aneurysms by Computational Fluid Dynamics

Hayashi, Yoshifumi, Yagi, Takanobu, Tobe, Yasutaka, Iwabuchi, Yuki, Yamanashi, Momoko, Takamura, Kenji, Iwasaki, Kiyotaka, Umezu, Mitsuo, Ishida, Takashi, Nakajima, Atsushi, Yoshida, Hirotaka, Nishitani, Kazutoshi, Ota, Yoshihisa, Sugawara, Michihito, Okada, Yoshifumi, Kubo, Toshiro, Kitahara, Shigemi

STROKE 44 ( 2 ) 2013 [Refereed]
Flexibility and Stent Fracture Potentials Against Cyclically Bending Coronary Artery Motions: Comparison Between 2-Link and 3-Link DESs.

Iwasaki, Kiyotaka, Kishigami, Sho, Arai, Jun, Ohba, Takafumi, Zhu, Xiaodong, Yamamoto, Tadashi, Hikichi, Yutaka, Umezu, Mitsuo

AMERICAN JOURNAL OF CARDIOLOGY 111 ( 7 ) 26B - 26B 2013
冠動脈ステントの3回拡張法と臨床実践での評価

山本匡, 岩崎清隆, 新井淳, 北原茂実, 梅津光生

生体医工学 52 ( 6 ) 350 - 356 2013
My 40 Year Journey

UMEZU Mitsuo

Journal of the Japan Society of Mechanical Engineers 116 ( 1130 ) 50 - 53 2013.01

CiNii
In vitro fabrication of functional three-dimensional tissues with perfusable blood vessels

Hidekazu Sekine, Tatsuya Shimizu, Katsuhisa Sakaguchi, Izumi Dobashi, Masanori Wada, Masayuki Yamato, Eiji Kobayashi, Mitsuo Umezu, Teruo Okano

Nature communications, Macmillan Publishers Limited 1 - 10 2013.01 [Refereed]

DOI
医療機器の非臨床評価

岩崎清隆, 梅津光生, 笠貫宏

第25回バイオエンジニアリング講演会講演論文集 17 - 18 2013.01
凍結乾燥及び滅菌処理を施した無細胞化ウシ腱の一定ひずみ繰り返し引張り試験による粘弾性特性評価

山野俊明, 岩崎清隆, 吉永卓斗, 金子譲, ヌールカティージャ, 齋藤峻平, 柴田悠矢, 梅津光生

第25回バイオエンジニアリング講演会講演論文集 235 - 236 2013.01
個々のヒト赤血球の衝突・破壊動態の指標化に関する検討

木田大輔, 八木高伸, 岩本理沙, 梅谷康太郎, 梅津光生

第25回バイオエンジニアリング講演会講演論文集 333 - 334 2013.01
ヒト未破裂脳動脈瘤の瘤壁の菲薄化を術前に予測する血流診断法の確立

八木高伸, 戸部泰貴, 岩渕裕貴, 山梨桃子, 高村兼司, 岩崎清隆, 梅津光生, 林祥史, 岡田義文, 吉田浩貴, 北原茂実

第25回バイオエンジニアリング講演会講演論文集 523 - 524 2013.01
ヒト未破裂脳動脈瘤の瘤壁の菲薄化に関する血流・病理統合解析

戸部泰貴, 八木高伸, 岩渕裕貴, 山梨桃子, 高村兼司, 岩崎清隆, 梅津光生, 林祥史, 岡田義文, 吉田浩貴, 北原茂実

第25回バイオエンジニアリング講演会講演論文集 525 - 526 2013.01
膝の屈伸に伴う浅大腿動脈のねじり変形と長軸方向圧縮変形を模擬した複合負荷装置を用いた末梢ステントの追従性評価

岸上翔, 岩崎清隆, 新井淳, 大場貴文, 山本匡, 挽地裕, 梅津光生

第25回バイオエンジニアリング講演会講演論文集 527 - 528 2013.01
「新しい僧帽弁位ステントレス生体弁 Normo」の開発

加瀬川均, 岩崎清隆, 梅津光生

人工臓器 41 ( 3 ) 176 - 179 2012.12

DOI CiNii
開胸を伴う手術でのナビゲーションを用いた体表から体内の標的血管へのアプローチ決定

植松美幸, 市橋琢弥, 安里権也, 梅津光生, 中岡竜介, 松岡厚子, 飯村浩, 青見茂之, 鈴木孝司, 村垣善浩, 伊関洋

,第25回日本内視鏡外科学会総会特別ワークショップ主日ナビゲーションはどこまで進化したか 2 - 3 2012.12
TAAA Navigatorの開発と臨床的評価の実際

植松美幸, 市橋琢弥, 安里権也, 梅津光生, 中岡竜介, 松岡厚子, 飯村浩, 青見茂之, 山崎健二, 鈴木孝司, 村垣善浩, 伊関洋

,日本コンピュータ外科学会誌, 14 ( 3 ) 356 - 357 2012.11

CiNii
医工連携ともう一つのEBM

梅津光生, 岩崎清隆, 伊関洋, 笠貫宏, 朴栄光, 村垣善治

日本コンピュータ外科学会誌 14 ( 3 ) 188 - 189 2012.11
解剖学的特徴点計測における誤差評価についての実験的検討

安里権也, 植松美幸, 市橋琢弥, 梅津光生, 中岡竜介, 松岡厚子, 飯村浩, 青見茂之, 山崎健二, 鈴木孝司, 村垣善浩, 伊関洋

日本コンピュータ外科学会誌 14 ( 3 ) 224 - 225 2012.11
弓部大動脈瘤用ステント留置課程のデータに基づく可視化に向けた初期的検討

市橋琢弥, 植松美幸, 安里権也, 梅津光生, 中岡竜介, 松岡厚子, 東隆, 山崎健二, 鈴木孝司, 村垣善浩, 伊関洋

日本コンピュータ外科学会誌 14 ( 3 ) 396 - 397 2012.11
大動脈の血流分配を再現する数値流体計算の出口境界条件の検討

木浦千賀子, 八木高伸, 中村匡徳, 岩崎清隆, 銭逸, 奥田茂男, 梅津光生

日本コンピュータ外科学会誌 14 ( 3 ) 404 - 405 2012.11
宮崎翔平,板谷慶一,本田崇,宮地鑑,石井正浩,梅津光生

Fontan循環における呼吸, 心拍変動がもたらす吻合部血流への影響

第32回日本小児循環動態研究会学術集会プログラム・抄録集 18 2012.11
システムダイナミクスにもとづくEVAHEARTTMの承認プロセスのモデリング〜行政と学会の関与〜

加藤二子, 梅津光生, 高橋裕, 岩崎清隆, 笠貫宏

第50回日本人工臓器学会大会予稿集 41 ( 2 ) S - 83 2012.11
EVAHEARTの開発過程における最悪リスク想定下での溶血試験の重要性

梅津光生, 岩崎清隆, 宮越貴之, 得能敏正, 山崎俊一, 山崎健二

第50回日本人工臓器学会大会予稿集 41 ( 2 ) S - 93 2012.11
移植可能な組織片開発へ向けた動静脈閉鎖系心筋組織構築

田中裕也, 坂口勝久, 清水達也, 関根秀一, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

第50回日本人工臓器学会大会予稿集 41 ( 2 ) S - 113 2012.11
心臓代用弁の弁性能試験に定圧漏れ試験データは必要か

梅津光生, 立田良太, 土居徹哉, 岡田昂大, ムンソジョン, 岩崎清隆, 藤本哲男

,第50回日本人工臓器学会大会予稿集 41 ( 2 ) s - 148 2012.11
機械式人工弁の弁性能が国循型補助人工心臓の性能に与える影響の検討

土居徹哉, 岡田昂大, ムンソジョン, 五十嵐利博, 伊藤一彦, 岩崎清隆, 藤本哲男, 山崎健二, 梅津光生

第50回日本人工臓器学会大会予稿集 41 ( 2 ) S - 154 2012.11
新しいステントレス僧帽弁(Normo弁)のIn-vitro血行動態評価

真鍋晋, 加瀬川均, 土居徹哉, 岡田昂大, ムンソジョン, 岩崎清隆, 藤本哲男, 笠貫宏, 梅津光生

第50回日本人工臓器学会大会予稿集 41 ( 2 ) S - 171 2012.11
薬剤・薬剤の用量・材料の違いが抗血栓性に及ぼす影響の検討

永井美玲, 岩崎清隆, 松橋祐輝, 高橋東, 梅津光生, 尾崎眞

第50回日本人工臓器学会大会予稿集 41 ( 2 ) s - 174 2012.11
心筋脂肪シートによるチューブ状組織モデルの構築と内圧負荷のための潅流培養装置の開発

鶴山晋平, 坂口勝久, 清水達也, 関根秀一, 青木信奈子, 松浦勝久, 梅津光生, 岡野光夫

第50回日本人工臓器学会大会予稿集 41 ( 2 ) S - 193 2012.11
厚い心筋組織構築に向けた血管導入技術の検討

坂口勝久, 清水達也, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

第50回日本人工臓器学会大会予稿集 41 ( 2 ) s - 174 2012.11
Tensile Strength of Human Pericardium Treated with Glutaraldehyde

Hiromasa Yamashita, Shigeyuki Ozaki, Kiyotaka Iwasaki, Isamu Kawase, Yukinari Nozawa, Mitsuo Umezu

ANNALS OF THORACIC AND CARDIOVASCULAR SURGERY 18 ( 5 ) 434 - 437 2012.10 [Refereed]

　View Summary

Purpose: We have reconstructed aortic valves using autologous pericardium treated with glutaraldehyde since April 2007. However, the strength of the human pericardium has not been confirmed. We compared tensile strength between glutaraldehyde-treated human pericardium and aortic valve leaflets with various degrees of calcification to determine their suitability for use in aortic valve reconstruction.
Methods: We measured the ultimate tensile strength and elasticity of samples of glutaraldehyde-treated pericardia (n = 8), non-calcified (n = 12), calcified (n = 9) and decalcified (n = 21) aortic leaflets collected from 23 patients who underwent aortic valve surgery. Aortic valves were decalcified using a cavitational ultrasonic surgical aspirator. The pericardium was immersed in 0.6% buffered glutaraldehyde for 10 minutes and then rinsed three times for 6 minutes each in normal saline.
Results: The ultimate tensile strength of the glutaraldehyde-treated human pericardium, non-calcified, calcified and decalcified leaflets was 10, 2.8, 1.0 and 0.8 MPa, respectively.
Conclusions: The ultimate tensile strength of glutaraldehyde-treated human pericardium was 4 times higher than non-calcified leaflets, indicating its suitability for application to aortic valve reconstruction. Calcified leaflets were slightly stronger than decalcified leaflets. Thus, calcification can be removed without altering the tensile strength of valve materials.

DOI

Scopus

26

Citation

(Scopus)
Investigation on the outlet boundary conditions of computational fluid dynamics for reproducing the flow distribution of the aorta

KONOURA C, YAGI T, NAKAMURA M, IWASAKI K, QIAN Y, OKUDA S, UMEZU M

14 ( 3 ) 404 - 405 2012.10

CiNii
A Preliminary study for the visualization of stent-graft placement in the aortic arch

ICHIHASHI T, UEMATSU M, ASATO K, UMEZU M, NAKAOKA R, MATSUOKA A, AZUMA T, YAMAZAKI K, SUZUKI T, MURAGAKI Y, ISEKI H

14 ( 3 ) 396 - 397 2012.10

CiNii
An experimental study for the evaluation of measurement errors on anatomical landmarks

ASATO K, UEMATSU M, ICHIHASHI T, UMEZU M, NAKAOKA R, MATSUOKA A, IIMURA H, AOMI S, YAMAZAKI K, SUZUKI T, MURAGAKI Y, ISEKI H

14 ( 3 ) 224 - 225 2012.10

CiNii
Medical-Engineering Collaboration Operated by a Philosophy of Another EBM (Engineering Based Medicine)

UMEZU M, IWASAKI K, ISEKI H, KASANUKI H, PARK Y, MURAGAKI Y

14 ( 3 ) 188 - 189 2012.10

CiNii
Development of TAAA Navigator : preclinical and clinical findings

UEMATSU M, ICHIHASHI T, ASATO K, UMEZU M, NAKAOKA R, MATSUOKA A, IIMURA H, AOMI S, YAMAZAKI K, SUZUKI T, MURAGAKI Y, ISEKI H

,日本コンピュータ外科学会誌, 14 ( 3 ) 356 - 357 2012.10
Engineering vascularized cardiac tissue in vitro

K Sakaguchi, Y Tanaka, h Sekine, T Shimizu, M Yamato, M Umezu, T Okano

Journal of tissue Engineering and Regenerative Medicine 3rd TERMIS World Congress 2012 353 2012.09 [Refereed]
植込み型迷走神経刺激装置の承認に至るまでの経緯

小野村章, 川合謙介, 伊関洋, 梅津光生

第2回レギュラトリーサイエンス学会学術大会レギュラトリーサイエンスの実践と活用プログラム・抄録集,レギュラトリーサイエンス学会誌,vol.2 61 2012.09
市販後の医療機器の性能評価データを開発プロセスにフィードバックするための一つの景観

梅津光生, 岩崎清隆, 朴栄光, 笠貫宏

,第2回レギュラトリーサイエンス学会学術大会レギュラトリーサイエンスの実践と活用プログラム・抄録集,レギュラトリーサイエンス学会誌,vol.2 63 2012.09
迷走神経刺激と承認課程

小野村章, 川合謙介, 伊関洋, 梅津光生

第4回RS専門研究会プログラム・抄録集 6 2012.09
入院患者のベッドからの転落未然検出システム」の開発過程における有用性及び安全性、機能性、限界評価基準の研究

大津良司, 伊関洋, 梅津光生

第4回RS専門研究会プログラム・抄録集 10 2012.09
人工血管血流配分性能評価にむけての大動脈血流解析手法の検討

木浦千賀子, 八木高伸, 中村匡徳, 岩崎清隆, 銭逸, 奥田茂男, 梅津光生

第4回RS専門研究会プログラム・抄録集 10 2012.09
新規医療機器の試験デザインと承認意思決定—アメリカ食品医薬品局(FDA)のリスクべべフィットバランス-

村垣善浩, 植松美幸, 松岡厚子, 伊関洋, 佐久間一郎, 笠貫宏, 梅津光生

第4回RS専門研究会プログラム・抄録集 12 2012.09
医療機器開発フローの可視化

加藤二子, 梅津光生, 高橋裕, 岩崎清隆, 笠貫宏

第4回RS専門研究会プログラム・抄録集 13 2012.09
Fabrication of three-dimensional tubular cardiac tissue using neonatal mouse cardiomyocytes

S Tsuruyama, K Sakaguchi, T Shimizu, H Sekine, S Aoki, K Matsuura, M Umezu, T Okano

Journal of tissue Engineering and redenerative Medicine 6 24 2012.09 [Refereed]
Infuluences of anticoagulants, Activated clotting time, and bloodcontact materials on thrombogenicity: comparative study using fresh blood samples

Nagai M, Iwasaki K, Matsuhashi Y, Takahashi A, Miyagawa T, Ozaki M, Umezu M

The InternationalJournal of artificial organs 35 ( 8 ) 555 2012.09
Fabrication of vascularized myocardial tissue in a perfusion bioreactor

Yuya Tanaka, Katsuhisa Sakaguchi, Tatsuya Shimizu, Masayuki Yamato, Mitsuo Umezu, Teruo Okano

2012 ISOMRM The 2nd International Symposium of Materials on Regenerative Medicine Abctract book 103 2012.08
Consyruction of fuctional neo-vessel from human cells in vitro

Y-H.Lo, Y Nakayama, s Horaguchi, KSakaguchi, T Shimizu, M Yamato, M Umezu, T Okano

2012 ISOMRM The 2nd International Symposium of Materials on Regenerative Medicine Abctract book 2012.08
Influence of surgical arch reconstruction methods on single ventricle workload in the Norwood procedure

Keiichi Itatani, Kagami Miyaji, Yi Qian, Jin Long Liu, Tomoyuki Miyakoshi, Arata Murakami, Minoru Ono, Mitsuo Umezu

JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY 144 ( 1 ) 130 - 138 2012.07 [Refereed]

　View Summary

Objective: The study objective was to evaluate various types of Norwood arch reconstruction methods and to show the factors that affect the cardiac workload of the single ventricle. The Norwood procedure is one of the most challenging congenital heart surgeries. Several aortic arch reconstruction techniques have been reported to avoid recoarctation, ensure coronary perfusion, and improve long-term outcomes. Inside the arch, complicated turbulent flow is generated; however, little is known about the cause of the disadvantageous inefficient flow and the surgical techniques to avoid it.
Methods: We created patient-specific computational hemodynamic models of 9 patients who underwent different types of arch reconstruction methods. Four patients had aortic atresia, and 5 patients had aortic stenosis. Flow profiles were defined by echocardiography data corrected with body surface area. Turbulent pulsatile flow was analyzed with the finite volume method. Flow energy loss was calculated to estimate cardiac workload, and wall shear stress was calculated to estimate vessel wall stiffness increase.
Results: Recoarctation and acute arch angles increased wall shear stress and energy loss. In the patients with aortic atresia, a longitudinal incision toward the descending aorta was effective in creating a smooth arch angle. In the patients with aortic stenosis, arch repair with the Damus-Kaye-Stansel procedure in a single anastomotic site was effective in creating sufficient anastomosis space and a smooth arch angle.
Conclusions: Creation of a large anastomotic space and a smooth aortic arch angle reduced wall shear stress and energy loss, and should improve long-term cardiac performance after the Norwood procedure. (J Thorac Cardiovasc Surg 2012;144:130-8)

DOI

Scopus

86

Citation

(Scopus)
Engineering analysis of the effects of bulging sinus in a newly designed paediatric pulmonary heart valve on hemodynamic function

SUZUKI Ichiro, YABE Shota, MATSUE Ken, SUGAI Telma Keiko, TSUBOKO Yusuke, SAIJO Yoshifumi, YOSHIZAWA Makoto, KAMEYAMA Takeyoshi, SHIRAISHI Yasuyuki, YAMBE Tomoyuki, FENG Zhonggang, OKAMOTO Yoshihiro, TANAKA Takashi, UMEZU Mitsuo, MIYAZAKI Takako, YAMAGISHI Masaaki

41 ( 1 ) 59 - 61 2012.06 [Refereed]

CiNii
Viscoelastic characteristics of contracted collagen gels populated with rat fibroblasts or cardiomyocytes

FENG Zhonggang, SEYA Daiki, KITAJIMA Tatsuo, KOSAWADA Tadashi, NAKAMURA Takao, UMEZU Mitsuo

41 ( 1 ) 43 - 44 2012.06

CiNii
マウス胎児由来心筋細胞シートを用いたチューブ状三次元組織の構築

鶴山晋平, 坂口勝久, 清水達也, 関根秀一, 青木信奈子, 松浦勝久, 梅津光生, 岡野光夫

再生医療増刊号 11 180 2012.06
生体外における動静脈閉鎖系心筋組織構築

田中裕也, 清水達也, 関根秀一, 坂口勝久, 洞口重人, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

再生医療増刊号 11 250 2012.06
レギュラトリーサイエンスにおける評価科学で重要なこと

岩崎清隆, 挽地裕, 梅津光生

生体医工学,第50巻特別号 50 84 2012.05
医療レギュラトリーサイエンスで育成すべき人材とは:TWInsの共同大学院における人材育成

梅津光生, 有賀淳, 池田康夫, 伊関洋, 岩崎清隆, 笠貫宏, 武岡真司, 大和雅之

生体医工学,第50巻特別号 50 85 2012.05
3次元心筋組織構築デバイスの開発

坂口勝久, 清水達也, 田中裕也, 関根秀一, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

生体医工学,第50巻特別号 50 88 2012.05
In vitro assessment of hyperacute immune reaction to decellularized freeze-dried and sterilized bovine pericardium

A Takahashi, K Iwasaki, Y Matsuhashi, M Nagai, T Fujimoto, S Ozaki, M Umezu

World congress on Medical Physics and Biomedical Engineering Final Program TH.08 03.2-4 2012.05
Comparison of computational hemodynamic simulation with fluid circulating experiment on cardiovascular flow at Aortic region

J.L.Liu, Y, Qian, H Yasuda, K Itatani, K Miyaji, Q Sun, J.F.Liu, M Umezu

World congress on Medical Physics and Biomedical Engineering Final Program TH.07 02.4-5 2012.05
Risk management of clinical left ventricular system(LVAS)in Japan

Mitsuo Umezu, Kiyotaka Iwasaki, Kenji Yamazaki, Toshihiro Igarashi, Takashi Tanaka, Tomoya Kitano, Shunichi Yamazaki

World congress on Medical Physics and Biomedical Engineering Final Program TH.08 03.2-4 2012.05
ヒト鮮血を用いた無細胞化処理及び滅菌した動物由来組織の非臨床超急性免疫反応評価

岩崎清隆, 松橋祐輝, 高橋東, 宮川充, 永井美玲, 尾崎重之, 梅津光生

第35回日本バイオレオロジー学会年会プログラム・抄録集 100100 2012.05
Fabrication of functional three-dimensional tissues by stacking cell sheets in vitro.

Yuji Haraguchi, Tatsuya Shimizu, Tadashi Sasagawa, Hidekazu Sekine, Katsuhisa Sakaguchi, Tetsutaro Kikuchi, Waki Sekine, Sachiko Sekiya, Masayuki Yamato, Mitsuo Umezu, Teruo Okano

Nature protocols 7 ( 5 ) 850 - 8 2012.04 [Refereed] [International journal]

　View Summary

The fabrication of 3D tissues retaining the original functions of tissues/organs in vitro is crucial for optimal tissue engineering and regenerative medicine. The fabrication of 3D tissues also contributes to the establishment of in vitro tissue/organ models for drug screening. Our laboratory has developed a fabrication system for functional 3D tissues by stacking cell sheets of confluent cultured cells detached from a temperature-responsive culture dish. Here we describe the protocols for the fabrication of 3D tissues by cell sheet engineering. Three-dimensional cardiac tissues fabricated by stacking cardiac cell sheets pulsate spontaneously, synchronously and macroscopically. Via this protocol, it is also possible to fabricate other tissues, such as 3D tissue including capillary-like prevascular networks, from endothelial cells sandwiched between layered cell sheets. Cell sheet stacking technology promises to provide in vitro tissue/organ models and more effective therapies for curing tissue/organ failures.

DOI PubMed

Scopus

336

Citation

(Scopus)
Engineering analysis of the effects of bulging sinuses in a newly designed pediatric pulmonary heart valve on hemodynamic function.

Ichiro Suzuki, Yasuyuki Shiraishi, Shota Yabe, Yusuke Tsuboko, Telma Keiko Sugai, Ken Matsue, Takeyoshi Kameyama, Yoshifumi Saijo, Takashi Tanaka, Yoshihiro Okamoto, Zhonggang Feng, Takako Miyazaki, Masaaki Yamagishi, Makoto Yoshizawa, Mitsuo Umezu, Tomoyuki Yambe

Journal of artificial organs : the official journal of the Japanese Society for Artificial Organs 15 ( 1 ) 49 - 56 2012.03 [Refereed] [Domestic journal]

　View Summary

The purpose of this study was to examine the hemodynamic characteristics of expanded polytetrafluoroethylene (ePTFE) pulmonary valves with bulging sinuses quantitatively in a pediatric pulmonary mechanical circulatory system designed by us, in order to propose the optimal design for clinical applications. In this study, we developed a pediatric pulmonary mock circulation system, which consisted of a pneumatic right ventricular model, a pulmonary heart valve chamber, and a pulmonary elastic compliance tubing with resistive units. The hemodynamic characteristics of four different types of ePTFE valves and a monoleaflet mechanical heart valve were examined. Relationships between the leaflet movements and fluid characteristics were evaluated based on engineering analyses using echocardiography and a high-speed video camera under the pediatric circulatory conditions of the mock system. We successfully performed hemodynamic simulations in our pediatric pulmonary circulatory system that could be useful for quantitatively evaluating the pediatric heart valves. In the simulation study, the ePTFE valve with bulging sinuses exhibited a large eddy in the vicinity of the leaflets, whereas the straight tubing exhibited turbulent flow. The Reynolds number obtained in the valve with bulging sinuses was calculated to be 1667, which was smaller than that in the straight tubing (R (e) = 2454).The hemodynamic characteristics of ePTFE pediatric pulmonary heart valves were examined in our mock circulatory system. The presence of the bulging sinuses in the pulmonary heart valve decreased the hydrodynamic energy loss and increased the systolic opening area. Based on an in vitro experiment, we were able to propose an optimal selection of pulmonary valve design parameters that could yield a more sophisticated pediatric ePTFE valve shape.

DOI PubMed

Scopus

27

Citation

(Scopus)
OPCABの遠隔成績を向上させる医工学的武器とは-教育と実践から-

小坂眞一, 朴栄光, 小川大輔, 梅津光生

医工学治療日本医工学治療学会第28回学術大会抄録集 24 79 2012.03
OPCABの遠隔成績を向上させる医工学的武器とは—教育と実践から—,

小坂眞一, 朴栄光, 小川大輔, 梅津光生

医工学治療、 24 79 2012.03
レギュラトリーサイエンスを考慮した人工心臓の市販後に有用な医工学実験と解析アプローチ

岩崎清隆, 梅津光生, 八木高伸, 朴栄光, 笠貫宏

第40回人工心臓と補助循環懇話会プログラム・抄録集 38 2012.02
壁面衝突する個々の赤血球のリアルタイム動態観察と溶血の関連性

八木高伸, 関裕子, 木田大輔, 岩本理沙, 梅津光生

第40回人工心臓と補助循環懇話会プログラム・抄録集 45 2012.02
システムダイナミクスによる補助人工開発フローの可視化

加藤二子, 梅津光生, 岩崎清隆, 笠貫宏

第40回人工心臓と補助循環懇話会プログラム・抄録集 46 2012.02
補助人工心臓駆動下の血行動態を再現するシミュレータの作製

五十嵐利博, ムンソジョン, 岡田昂大, 土居徹哉, 安田大樹, 立田良太, 八木高伸, 岩崎清隆, 山崎健二, 梅津光生

第40回人工心臓と補助循環懇話会プログラム・抄録集,pp71 71 2012.02
富山の常備薬型補助心臓の開発を成功に導くには?

梅津光生, 岩崎清隆

第40回人工心臓と補助循環懇話会プログラム・抄録集 94 2012.02
Assessment of a novel stentless mitral valve using a pulsatile mitral valve simulator.

Kasegawa Hitoshi, Iwasaki Kiyotaka, Kusunose Shyunsuke, Tatusta Ryota, Doi Tetsuya, Yasuda Hiroki, Umezu Mitsuo

Assessment of a novel stentless mitral valve using a pulsatile mitral valve simulator. 21 ( 1 ) 2012 [Refereed]

　View Summary

BACKGROUND AND AIM OF THE STUDY:The study aim was to develop a novel stentless mitral valve (SMV) and to evaluate its performance, using an original pulsatile simulator developed specifically to analyze the hydrodynamic function of the mitral valve.;METHODS:The SMV developed at the authors' institution consists of two major components: a large anterior leaflet with commissures, and a small posterior leaflet. The valve is formed by suturing the leaflets (made from bovine pericardium) to a flexible (Duran) ring. The SMV, constructed with a 27 mm flexible ring, was installed into the mitral valve simulator, after which the four papillary flaps of the two leaflets were sutured to artificial papillary muscles. The artificial ventricle was driven pneumatically at a pulse rate of 70 beats/min, with a systolic fraction of 35%. The mean flow, aortic pressure, and atrial pressure were adjusted to 4.5 1/min, 120/80 mmHg, and 10 mmHg, respectively. A 27 mm mechanical valve (MEV; St. Jude Medical Inc.) was employed as a control. The hydrodynamic performance of the SMV and MEV were investigated and compared. An echo-Doppler study was also performed.;RESULTS:The waveforms of the SMV and MEV showed a similar pattern. The mean transvalvular flow was 4.7 +/- 0.4 1/min for the SMV, and 3.55 +/- 0.13 1/min for the MEV (p < 0.001). Mitral regurgitation was 5.07 +/- 1.15 and 3.78 +/- 0.35 ml/beat, respectively (p < 0.05). Echocardiographic data indicated that the regurgitant jet towards the left atrial model was none or trivial for the SMV, and trivial for the MEV.;CONCLUSION:Within the environment of the mitral valve simulator, the novel SMV prepared from bovine pericardium demonstrated excellent performance characteristics, and may represent a potential future alternative for bioprosthetic stented mitral valves.
Assessment of a Novel Stentless Mitral Valve Using a Pulsatile Mitral Valve Simulator

Hitoshi Kasegawa, Kiyotaka Iwasaki, Shyunsuke Kusunose, Ryota Tatusta, Tetsuya Doi, Hiroki Yasuda, Mitsuo Umezu

JOURNAL OF HEART VALVE DISEASE 21 ( 1 ) 71 - 75 2012.01 [Refereed]

　View Summary

Background and aim of the study: The study aim was to develop a novel stentless mitral valve (SMV) and to evaluate its performance, using an original pulsatile simulator developed specifically to analyze the hydrodynamic function of the mitral valve.
Methods: The SMV developed at the authors' institution consists of two major components: a large anterior leaflet with commissures, and a small posterior leaflet. The valve is formed by suturing the leaflets (made from bovine pericardium) to a flexible (Duran) ring. The SMV, constructed with a 27 mm flexible ring, was installed into the mitral valve simulator, after which the four papillary flaps of the two leaflets were sutured to artificial papillary muscles. The artificial ventricle was driven pneumatically at a pulse rate of 70 beats/min, with a systolic fraction of 35%. The mean flow, aortic pressure, and atrial pressure were adjusted to 4.5 l/min, 120/80 mmHg, and 10 mmHg, respectively. A 27 mm mechanical valve (MEV; St. Jude Medical Inc.) was employed as a control. The hydrodynamic performance of the SMV and MEV were investigated and compared. An echo-Doppler study was also performed.
Results: The waveforms of the SMV and MEV showed a similar pattern. The mean transvalvular flow was 4.7 +/- 0.4 l/min for the SMV, and 3.55 +/- 0.13 l/min for the MEV (p <0.001). Mitral regurgitation was 5.07 +/- 1.15 and 3.78 +/- 0.35 ml/beat, respectively (p <0.05). Echocardiographic data indicated that the regurgitant jet towards the left atrial model was none or trivial for the SMV, and trivial for the MEV.
Conclusion: Within the environment of the mitral valve simulator, the novel SMV prepared from bovine pericardium demonstrated excellent performance characteristics, and may represent a potential future alternative for bioprosthetic stented mitral valves.
人工心臓の臨床使用時における交換及び長期使用時の安全性に関する工学的検討

立田良太, 田中隆, 楠瀬俊祐, 安田大樹, 土居徹哉, 岡田昂大, 五十嵐利博, 伊藤一彦, 岩崎清隆, 梅津光生

第24回バイオエンジニアリング講演会講演論文集 8E16 2012.01
ラットの皮下に移植した無細胞ウシ心膜の力学的特性評価

早川知孝, 岩崎清隆, 金子譲, 吉永卓斗, 松田勇, 山野俊明, 尾崎重之, 梅津光生

第24回バイオエンジニアリング講演会講演論文集 7E21 2012.01
冠動脈ステント屈曲加速耐久試験の信頼性に関する検討

野口裕介, 岩崎清隆, 犬飼孟, 岸上翔, 新井淳, 山本匡, 挽地裕, 梅津光生

第24回バイオエンジニアリング講演会講演論文集 8E22 2012.01
血管網付ヒト三次元組織の構築に向けた新規培養装置の創出

洞口重人, 清水達也, 坂口勝久, 中山悠衣, 岩崎清隆, 大和雅之, 岡野光夫, 梅津光生

第24回バイオエンジニアリング講演会講演論文集 7F44 2012.01
右冠動脈屈曲モデルを用いた加速耐久試験装置による新生内膜がSUS316L製ステントの破損耐久性におよぼす影響の検討

岸上翔, 岩崎清隆, 野口裕介, 犬飼孟, 新井淳, 山本匡, 挽地裕, 梅津光生

第24回バイオエンジニアリング講演会講演論文集 8F44 2012.01
先天性心疾患の外科的治療に関するシミュレーションと実験との比較

安田大樹, 劉金龍, 立田良太, 土居徹哉, 岡田昂大, 板谷慶一, 銭逸, 梅津光生

第24回バイオエンジニアリング講演会講演論文集 7F13 2012.01
小児大動脈血流シミュレーションにおける末梢反射応答を加味した出口境界条件の検討

宮崎翔平, 板谷慶一, 劉金龍, 銭逸, 宮地鑑, 横田元, 梅津光生

第24回バイオエンジニアリング講演会講演論文集 8F41 2012.01
EFDとCFDの比較による脳動脈瘤内の血流の衝突ダイナミクスに関する研究

高橋彩来, 八木高伸, 戸部泰貴, 岩淵裕貴, 山梨桃子, 岩崎清隆, 梅津光生, 村山雄一, 高尾洋之

第24回バイオエンジニアリング講演会講演論文集 8F46 2012.01
ヒト脳動脈瘤の外壁性状及び衝突流れの相関による組織菲薄化に関する検討

戸部泰貴, 八木高伸, 高橋彩来, 岩渕裕貴, 山梨桃子, 岩崎清隆, 梅津光生, 林祥史, 岡田義文, 菅原道仁, 北原茂実

第24回バイオエンジニアリング講演会講演論文集 8F47 2012.01
“Wind tunnel”in vascular hemodynamics: why and how?

T Yagi, S Takahashi, T Tobe, M Umezu, H Takao, Y Murayama

The 11th international Conference on Fluid Control, Measurements, and Visualization, 2011.12
Development and Evaluation of TAAA Navigator for Clinical Trials on Aortic Vascular Surgery

UEMATSU M, SAKAMOTO R, ICHIHASHI T, UMEZU M, MATSUOKA A, AOMI S, IIMURA H, NAKAMURA R, SUZUKI T, MURAGAKI Y, ISEKI H

13 ( 3 ) 404 - 405 2011.11

CiNii
実験的デバイス特性評価より導く、安全性向上のためのCAS適応およびデバイス選択

山家弘雄, 岡本吉弘, 犬飼孟, 岩崎清隆, 梅津光生, 三木潤一郎, 仲寛, 寺田友昭

Journal of Neuroendovascular Therapy 第27回NPO法人日本脳神経血管内治療学会学術総会プログラム抄録集 5 ( 4 ) 180 2011.11
CASにおけるステント構造とセルデザインの検討

山家弘雄, 岡本吉弘, 犬飼孟, 岩崎清隆, 梅津光生, 寺田友昭

Journal of Neuroendovascular Therapy 第27回NPO法人日本脳神経血管内治療学会学術総会プログラム抄録集 5 ( 4 ) 315 2011.11
Flux characteristics of cell culture medium in rectangular microchannels

Zhonggang Feng, Shuhei Fukuda, Michio Yokoyama, Tatsuo Kitajima, Takao Nakamura, Mitsuo Umezu

JOURNAL OF ARTIFICIAL ORGANS 14 ( 3 ) 238 - 244 2011.09 [Refereed]

　View Summary

Rectangular microchannels 50 mu m high and 30, 40, 50, 60, or 70 mu m wide were fabricated by adjusting the width of a gap cut in a polyethylene sheet 50 mu m thick and sandwiching the sheet between an acrylic plate and a glass plate. Flux in the microchannels was measured under three different inner surface conditions: uncoated, albumin-coated, and confluent growth of rat fibroblasts on the bottom of the microchannels. The normalized flux in microchannels with cultured fibroblasts or albumin coating was significantly larger than that in the uncoated channels. The experimental data for all microchannels deviated from that predicted by classical hydrodynamic theory. At small aspect ratio the flux in the microchannels was larger than that predicted theoretically, whereas it became smaller at large aspect ratio. The aspect ratio rather than Reynolds number is the correct property for predicting the variation of the normalized friction factor. We postulate that two counteracting effects, rotation of large molecules and slip velocity at the corners of the microchannels, are responsible for the deviation. From these results we conclude that albumin coating should be carried out in the same way as when fabricating our integrating cell-culture system. The outcomes of this study are not only important for the design of our culture system, but also quite informative for general microfluidics.

DOI

Scopus

4

Citation

(Scopus)
S021021 Development of a Decellularized Bovine Tendon for Anterior Cruciate Ligament Reconstruction

IWASAKI Kiyotaka, YOSHINAGA Takuto, YAMANO Toshiaki, HAYAKAWA Tomotaka, KANEKO Jo, OZAKI Shigeyuki, UMEZU Mitsuo

Mechanical Engineering Congress, Japan 2011 "S021021 - 1"-"S021021-3" 2011.09

　View Summary

Autologous tendons or bone-patellar tendon-bone grafts are clinically used for reconstruction of anterior cruciate ligaments, because of unsatisfactory durability of synthetic materials. The aims of this study are to realize decellularization of 16-cm long xenogeneic tendons which have a potential to guide regeneration, and to investigate influences of decellularization on tissue mechanical properties. Bovine tendons were decellularized by combination of pulsatile flow-and-pressure circulation of 1 wt% deoxycholic acid and microwave radiation. Then, the tissues were additionally treated with endonuclease. Influences of decellularization on durability was investigated by a cyclic tensile test under 0-100 N loads. When the tissues were not ruptured, ultimate strength, elastic modulus, and ultimate strain were examined by a uniaxial tensile test. DNA of 16-cm long bovine tendons was successfully removed over 99.99% by our decellularization technology. Non-treated and decellularized tendons were not ruptured in 1000 cycles' tensile durability tests. After the cyclic tests, ultimate stress, elastic modulus, and ultimate strain of the decellularized tendons were comparable to those of non-treated tendons. We here reported, to our knowledge, the first successful decellularization of 16-cm long tendons with preserving mechanical integrity.

CiNii
S021013 Investigation of tissue-degenerating hemodynamics in human cerebral aneurysms : correlation between bleb formation and flow impingement

YAGI Takanobu, HAYASHI Yoshifumi, TAKAHASHI Sara, TOBE Yasutaka, IWABUCHI Yuki, YAMANASHI Momoko, YAMAMOTO Tadashi, IWASAKI Kiyotaka, UMEZU Mitsuo, YOSHIDA Hirotaka, NISHITANI Kazutoshi, OHTA Yoshihisa, OKADA Yoshifumi, SUGAWARA Michihito, KUBO Toshiro, KITAHARA Shigemi

Mechanical Engineering Congress, Japan 2011 "S021013 - 1"-"S021013-4" 2011.09

　View Summary

This study aimed to investigate "malignant hemodynamics" leading to induce the wall degradation of cerebral aneurysms in an effort to find out a reliable predictor as to which aneurysms were doomed to rupture. Two blister-holding aneurysms and two bleb-holding aneurysms were computationally analyzed and compared with those of aneurysmal appearances observed during operations. The results demonstrated that the sites of flow impingement and bifurcation were well correlated with those of blisters. Such a flow pattern was confirmed to be present at the neck of bleb. The inside of bleb was found to be dominated by weak regurgitation as a result of flow bifurcation. The possible scenario for the genesis and growth of bleb was proposed. Flow impingement was concluded to play a malignant role on aneurysmal wall degradation.

CiNii
脳動脈瘤内の流れの遷移性に関して:計測・計算の比較によるモデリング留意点

八木高伸, 高橋彩来, 戸部泰貴, 岩崎清隆, 梅津光生, 高尾洋之, 村山雄一

第34回日本バイオレオロジー学会年会プログラム・抄録集 47 2011.06
灌流培養における3次元心筋組織の構築

坂口勝久, 清水達也, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

第34回日本バイオレオロジー学会年会プログラム・抄録集 85 2011.06
Experimental insight into spatial and temporal dynamics of wall shear rate using elastic replicas of human cerebral aneurysms with fluorescent stereo PIV

T.Yagi, M.Shinke, S.Takahashi, Y.Tobe, M.Umezu, H.Takao, Y.Murayama

The 11th Asian Symposium on Visualization(ASV 11)Program and Abstracts 98 2011.06
Flux characteristics of cell culture medium in rectangular microchannels

Zhonggang Feng, Shuhei Fukuda, Michio Yokoyama, Tatsuo Kitajima, Takao Nakamura, Mitsuo Umezu

Journal of Artificial Organs 14 ( 3 ) 238 - 244 2011.04 [Refereed]
三次元心筋組織構築に向けたバイオリアクターの創出

洞口重人, 清水達也, 関根秀一, 坂口勝久, 小倉伸也, 大和雅之, 梅津光生, 岡野光夫

再生医療,vol.10 suppl 2011 160 2011.02
微小血管流路デバイスを用いた生体内組織構築の検討

植木光樹, 坂口勝久, 洞口重人, 小倉伸也, 清水達也, 大和雅之, 梅津光生, 岡野光夫

再生医療, vol.10 suppl 2011 225 2011.02
Durability Test for Implantable Left Ventricle Assist System EVAHEART

KITANO Tomoya, MIYAKOSHI Takayuki, KOBAYASHI Shinji, TOKUNO Toshimasa, YAMAZAKI Kenji, IWASAKI Kiyotaka, UMEZU Mitsuo

BME 49 ( 6 ) 918 - 924 2011

　View Summary

A durability test of the implantable Left Ventricular Assist System EVAHEART was conducted to demonstrate that the EVAHEART Blood Pump can be run for 2 years without failing. This testing was useful to indicate potential for BTT and possibly DT applications. We developed a custom durability test mock circulation loop which generates a pulsatile flow simulating the native left ventricle. This mock circulation loop includes components which mimic the left ventricle (LV chamber) and compliance in the aorta (aortic column), and a loop which connects the blood pump to both the LV chamber (inlet) and the aortic column (outlet). The LV chamber has two one-way valves and a linear motor connected to a rolling seal, allowing it to generate pulsatile flow. The blood pump speed was tuned to achieve clinically relevant flow, based on the need to supplement a failing heart. The simulated heart rate (stroke rate of the linear actuator) cycled through 3 different settings each day to simulate changes in patient activity level. The sample size for the durability test was set to 18, and the test duration was 2 years. During the test, no critical blood pump failures were observed. There were no indications of significant decrease in pump performance or seal performance. Furthermore, no symptoms of failure, such as abnormal wear, were observed. In conclusion, the durability test successfully demonstrated that the EVAHEART Blood Pump achieved component reliability at a minimum of 90% reliability and 88% confidence interval over a mission life of two years.

DOI CiNii
Neointimal Coverage Reduces a Potential Risk of Stent Separation of Sirolimus Eluting Stent: Accelerated Durability Tests Under in-vivo Simulated Cyclically-Bended Proximal Right Coronary Artery Environment

Iwasaki, Kiyotaka, Hikichi, Yutaka, Yamamoto, Tadashi, Kishigami, Sho, Arai, Jun, Noguchi, Yusuke, Kasanuki, Hirhoshi, Umezu, Mitsuo

CIRCULATION 124 ( 21 ) 2011 [Refereed]
右冠動脈の屈曲変形を模擬した加速耐久試験装置を用いた異なる駆動周波数による冠動脈ステントの耐久性評価

八木下雄一, 岩崎清隆, 野口裕介, 岸上翔, 山本匡, 挽地裕, 梅津光生

第23回バイオエンジニアリング講演会講演論文集 21 2011.01
超高速イメージングによる衝突速度に応じた人赤血球のリアルタイム破壊動態解析

秋元祐紀, 八木高伸, 関裕子, 木田大輔, 梅津光生

第23回バイオエンジニアリング講演会講演論文集 383 2011.01
弾性脳動脈瘤モデルを用いたステレオPIV法による壁面せん断応力3次元計測と時間・空間特性

新家学, 佐藤絢香, 高橋彩来, 八木高伸, 梅津光生, 村山雄一, 高尾洋之

第23回バイオエンジニアリング講演会講演論文集 403 2011.01
吻合内腔形状の精密計測による血管吻合手技における訓練効果の定量的評価方法の検討

牧野穂高, 朴栄光, 穂芳郎, 浅野竜太, 梅津光生

第23回バイオエンジニアリング講演会講演論文集 411 2011.01
滅菌処理がウシ心膜組織に及ぼす影響:力学的特性と熱安定性

川辺治樹, 岩崎清隆, 柴崎剛, 竹野豊, 早川知孝, 金子譲, 吉永卓斗, 尾崎重之, 梅津光生

第23回バイオエンジニアリング講演会講演論文集 505 2011.01
脳動脈瘤の破裂を予測する医工学技術の確立に向けて

八木高伸, 銭逸, 高尾洋之, 村山雄一, 梅津光生

人工臓器 39 ( 3 ) 227 - 231 2010.12

DOI CiNii
循環シミュレータによる右心系心臓代用弁の血行動態評価

白石泰之, 鈴木一郎, 梅津光生, 山岸正明, 山家智之

人工臓器 39 ( 3 ) 214 - 217 2010.12

DOI CiNii
In vitro evaluations of blood flow pattern in left ventricle on ventricular assist device

IGARASHI Toshihiro, KOKUZAWA Yuma, KUME Rei, KUSUNOSE Shunsuke, TATSUTA Ryota, YAGI Takanobu, IWASAKI Kiyotaka, YAMAZAKI Kenji, UMEZU Mitsuo

37 ( 4 ) 409 - 412 2010.12

CiNii
Engineering vascularized cardiac tissue with cell sheet technology

Katsuhisa Sakaguchi, Tatsuya Shimizu, Shigeo Horaguchi, Shinya Ogura, Hidekazu ekine, Masayuki Yamato, Mitsuo Umezu, Teruo Okano

The TERMIS North America 2010 Annual Conference and Exposition program 2010.12
Construction of a bed for fabricating three-dimensional tissue in vitro

Shinya Ogura, Katsuhisa Sakaguchi, Shinsuke Noguchi, Tatsuya Shimizu, Masayuki Yamato, Mitsuo Umezu, Teruo Okano

The TERMIS North America 2010 Annual Conference and Exposition program 2010.12
Development of in vitro test system to assess hyperacute immune response to decellularized bovine pericardium using human donor blood

Kiyotaka Iwasaki, Hiroto Tomiya, Akihiko Tonegawa, Takasi Miyagawa, Mirei Nagai, Tetsuo Fujimoto, Shigeyuki Ozaki, Mitsuo Umezu

The TERMIS North America 2010 Annual Conference and Exposition program 2010.12
A comparative study of registration methods to reduce the target registration error in an intercostal artery

SAKAMOTO R, UEMATSU M, HSU C, ICHIHASHI T, UMEZU M, IIMURA H, AOMI S, NAKAMURA R, SUZUKI T, MURAGAKI Y, ISEKI H

12 ( 3 ) 424 - 425 2010.11

CiNii
Current clinical trials and future prospects in a surgical navigation system for the thoracoabdominal area

UEMATSU M, SAKAMOTO R, HSU C, ICHIHASHI T, UMEZU M, AOMI S, NAKAMURA R, SUZUKI T, MURAGAKI Y, ISEKI H

12 ( 3 ) 268 - 269 2010.11

CiNii
A novel vessel-extracting aided image system for for Endovascular Aortic Repair

HSU C, UEMATSU M, SAKAMOTO R, ICHIHASHI T, UMEZU M, AZUMA T, AOMI S, NAKAMURA R, SUZUKI T, MURAGAKI Y, ISEKI H

12 ( 3 ) 248 - 249 2010.11

CiNii
Construction of vascularized cardiac tissue in abioreactor

Katsuhisa Sakaguchi, Tatsuya Shimizu, Kiyotaka Iwasaki, Masayuki Yamato, Mitsuo Umezu, Teruo Okano

International symposium of materials regenerative medicine(ISOMRM) 129 2010.11
大動脈ステントグラフト挿入術を支援する血管輪郭表示システム

許家群, 植松美幸, 坂本怜, 市橋琢弥, 梅津光生, 東隆, 青見茂之, 中村亮一, 鈴木孝司, 村垣善浩, 伊関洋

第19回日本コンピュータ外科学会大会特集号 248 2010.11
胸腹部領域を対象にしたナビゲーションシステムの臨床応用の現状と課題

植松美幸, 坂本怜, 許家群, 市橋琢弥, 梅津光生, 青見茂之, 中村亮一, 鈴木孝司, 村垣善浩, 伊関洋

第19回日本コンピュータ外科学会大会特集号 268 2010.11
標的血管の位置合わせ誤差を軽減するためのレジストレーション法の比較検討

坂本怜, 植松美幸, 許家群, 市橋琢弥, 梅津光生, 飯村浩, 青見茂之, 中村亮一, 鈴木孝司, 村垣善浩, 伊関洋

第19回日本コンピュータ外科学会大会特集号 424 2010.11
細胞から心臓を創る〜血管網導入技術の開発〜

坂口勝久, 清水達也, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

人工臓器, 第48回日本人工臓器学会大会 39 ( 2 ) w2 - 02 2010.11
東洋紡績製国循型補助人工心臓のダイヤフラムの挙動解析モデルの検討

伊藤一彦, 五十嵐利博, 田中隆, 岩崎清隆, 銭逸, 藤本哲男, 梅津光生

人工臓器, 第48回日本人工臓器学会大会 39 ( 2 ) s - 93 2010.11
Bulging sinusを有するePTFE心臓代用弁の工学的評価

白石泰之, 鈴木一郎, 矢部翔太, Telma K Sugai, 山田昭博, 亀山剛義, 金子芳一, 北野智哉, 田中隆, 金野敏, 西條芳文, 梅津光生, 宮崎隆子, 山岸正明, 山家智之

人工臓器, 第48回日本人工臓器学会大会 39 ( 2 ) p6 - 07 2010.11
医工学的アプローチによる冠動脈バイパス手術訓練と手技の定量的評価

朴栄光, 牧野穂高, 穂積芳郎, 八木高伸, 梅津光生

人工臓器, 第48回日本人工臓器学会大会 39 ( 2 ) p5 2010.11
臨床現場で学んだ経験を基に使いやすさ向上を狙った大血管ナビゲーションシステム

植松美幸, 坂本怜, 許家群, 市橋琢弥, 梅津光生, 青見茂之, 中村亮一, 鈴木孝司, 村垣善浩, 伊関洋

人工臓器, 第48回日本人工臓器学会大会 39 ( 2 ) p5 - 03 2010.11
人工心筋の可能性

馬場敦, 細田眞悟, 梅津光生, 本間大, スガイテルマ・ケイコ, 劉紅箭, 白石泰之, 山家智之

人工臓器, 第48回日本人工臓器学会大会, 39 ( 2 ) p4 - 05 2010.11
血液循環シミュレータの新規医療デバイス(頚動脈ステント留置術用debris捕捉カテーテル)性能評価への応用

犬飼孟, 岡本吉弘, 小橋宏行, 古澤豊樹, 山家弘雄, 寺田友昭, 岩崎清隆, 梅津光生

人工臓器, 第48回日本人工臓器学会大会 39 ( 2 ) A5 - 10 2010.11
超高速リアルタイムイメージングを用いた壁面衝突によるヒト赤血球の破壊動態観察

八木高伸, 秋元裕紀, 関裕子, 木田大輔, 梅津光生

人工臓器, 第48回日本人工臓器学会大会 39 ( 2 ) 118 2010.11
人工弁の変更に係わる東洋紡績社製の補助人口心臓の有効かつ安全な駆動条件に関する検討

楠瀬俊祐, 久米嶺, 立田良太, 土居徹哉, 堤俊二, 東宮裕人, 安田大樹, 五十嵐利博, 田中隆, 伊藤一彦, 岩崎清隆, 梅津光生

人工臓器, 第48回日本人工臓器学会大会, 39 ( 2 ) 84 2010.11
ヒト血液と無細胞組織の超急性免疫反応評価実験の開発

岩崎清隆, 東宮裕人, 利根川明宏, 宮川充, 永井美玲, 藤本哲男, 尾崎重之, 梅津光生

人工臓器, 第48回日本人工臓器学会大会 39 ( 2 ) 56 2010.11
大動脈ステントグラフト留置を支援する画像表示システムの開発

許家群, 植松美幸, 坂本怜, 市橋琢弥, 梅津光生, 東隆, 青見茂之, 中村亮一, 鈴木孝司, 村垣善浩, 伊関洋

日本生体医工学会関東支部若手研究者発表会2010 5 2010.11
A new trial towards an establishment of optimal surgery for congenital heart disease using CFD technology

Liu JL, Qian Y, Miyakoshi T, Itatani K, Miyaji K, Miurakami A, Ono M, Umezu M

人工臓器, 第48回日本人工臓器学会大会 39 ( 2 ) s - 89 2010.11
Filter wire EZ のdebris 回収能力の実験的検討

山家弘雄, 岡本吉弘, 小橋宏行, 犬飼孟, 古澤豊樹, 岩崎清隆, 梅津光生, 寺田友昭, 板倉徹

JNET 4 ( 4 ) 358 2010.11
ステントの構造より検討したWall stent の特性

山家弘雄, 岡本吉弘, 犬飼孟, 古澤豊樹, 小橋宏行, 田中智美, 谷田裕紀, 岩崎清隆, 梅津光生, 寺田友昭, 板倉徹

JNET 4 ( 4 ) 286 2010.11
Comparing Accuracy of Cerebral Aneurysm Size Measurements From Three Routine Investigations: Computed Tomography, Magnetic Resonance Imaging, and Digital Subtraction Angiography

Hiroyuki Takao, Yuichi Murayama, Toshihiro Ishibashi, Takayuki Saguchi, Masaki Ebara, Hideki Arakawa, Koreaki Irie, Kiyotaka Iwasaki, Mitsuo Umezu, Toshiaki Abe

NEUROLOGIA MEDICO-CHIRURGICA 50 ( 10 ) 893 - 899 2010.10 [Refereed]

　View Summary

Modern imaging technologies, such as computed tomography (CT) angiography, magnetic resonance (MR) angiography, and digital subtraction (DS) angiography are widely used for pretreatment evaluation of cerebral aneurysms, but the relative accuracies of these modalities are unclear. This study compared the measurements of aneurysm neck and dome height and width on CT angiography, time-of-flight (TOF)-MR angiography, and DS angiography using a three-dimensional workstation. An elastic model of a side-wall aneurysm was connected to an artificial heart pulsatile circuit system. The aneurysm model was prepared using a silicone membrane of 0.6-mm thickness under normal physiological circulation parameters. Using this aneurysm model, three-dimensional TOF-MR angiography, contrast-enhanced CT angiography, and DS angiography were performed. Source images were post-processed on a dedicated workstation to calculate the aneurysm size. DS angiography measurements were found to be the most accurate. In contrast, aneurysm neck sizes measured on CT angiography were significantly wider than actual values (p < 0.05) and aneurysm heights measured using TOF-MR angiography were significantly lower than actual values (p < 0.01). In this in-vitro model, at least one aneurysm dimension measured with CT angiography and with TOF-MR angiography differed significantly from actual values. Aneurysm neck width markedly affects therapeutic planning, as a wide neck requires craniotomy or endovascular treatment using an adjunctive device, so inaccuracies should be considered when aneurysm treatment is planned using modern methods of visualization.
Japanese Guidance for Ventricular Assist Devices/Total Artificial Hearts

Takashi Yamane, Shunei Kyo, Hikaru Matsuda, Yusuke Abe, Kou Imachi, Toru Masuzawa, Takeshi Nakatani, Kazuhiro Sase, Koichi Tabayashi, Setsuo Takatani, Eisuke Tatsumi, Mitsuo Umezu, Toshie Tsuchiya

ARTIFICIAL ORGANS 34 ( 9 ) 699 - 702 2010.09 [Refereed]

　View Summary

To facilitate research and development (R&D) and to expedite the review processes of medical devices, the Ministry of Health, Labor and Welfare (MHLW) and the Ministry of Economy, Trade and Industry (METI) founded a joint committee to establish guidance for newly emerging technology. From 2005 to 2007, two working groups held discussions on ventricular assist devices and total artificial hearts, including out-of-hospital programs, based on previous guidance documents and standards. Based on this discussion, the METI published the R&D Guidelines for innovative artificial hearts in 2007, and in 2008 the MHLW published a Notification by Director regarding the evaluation criteria for emerging technology.

DOI

Scopus

13

Citation

(Scopus)
Viscoelastic characteristics of contracted collagen gels populated with rat fibroblasts or cardiomyocytes

Zhonggang Feng, Daiki Seya, Tatsuo Kitajima, Tadashi Kosawada, Takao Nakamura, Mitsuo Umezu

JOURNAL OF ARTIFICIAL ORGANS 13 ( 3 ) 139 - 144 2010.09 [Refereed]

　View Summary

The viscoelastic characteristics of contracted collagen gels populated with rat fibroblasts or cardiomyocytes were investigated by uniaxial tensile testing. Rat type I collagen-Dulbecco's modified Eagle's medium solution (each 2 ml in volume, 0.5 mg/ml collagen concentration) containing 2.0 million rat fibroblasts or cardiomyocytes were cast in a circular shape. After gelation and culture for 10 days the contracted gels were first stretched to a tensile strain of approximately 0.20 at 4.6 x 10(-3)/s strain rate, and then the strain was kept unchanged for 3 min. The tensile stress in the gels was recorded. The results were regressed against the equations of the Kelvin viscoelastic model. It was found that the two elastic coefficients in the model were 6.5 +/- A 1.7 and 10.2 +/- A 3.2 kPa, respectively, for gels with cardiomyocytes and 5.1 +/- A 1.6 and 4.5 +/- A 0.9 kPa for those with fibroblasts; the values for gels with cardiomyocytes were significantly higher than those for gels with fibroblasts. The viscous coefficient was 169.6 +/- A 60.7 kPa s for the cardiomyocytes and 143.6 +/- A 44.7 kPa s for the fibroblasts. The relaxation time constant for gels with cardiomyocytes was 19.6 +/- A 10.6 s, significantly smaller than for gels with fibroblasts (36.4 +/- A 13.3 s). This study is the first to obtain viscoelastic data for living cell-contracted collagen gels. These data show that the viscous effect has a vital effect on the mechanical behavior of the gels and cannot be neglected in the culture and function of artificial substitutes based on contracted collagen gels. Furthermore, the data may imply that viscous coefficient of the gels might be closely related to collagen density rather than to cross linking among collagen fibrils.

DOI

Scopus

12

Citation

(Scopus)
目標血管位置の特定のための皮下組織厚の影響縮小による位置決め誤差の削減

植松美幸, 中野喜隆, 許家群, 坂本怜, 梅津光生, 青見茂之, 中村亮一, 鈴木孝司, 村垣善浩, 伊関洋

生体医工学シンポジウム2010 2-11-2 2010.09
体表面レジストレーションの導入による手術ナビゲーションシステム運用の改善

植松美幸, 坂本怜, 許家群, 市橋琢弥, 梅津光生, 青見茂之, 中村亮一, 鈴木孝司, 村垣善浩, 伊関洋

生活生命支援医療工学系連合大会2010講演論文集 10 ( 52 ) 443 - 446 2010.09
Construction of vascularized myocardial tissue based on a cell sheet engineering,

Shigeto Horaguchi, Tatsuya Shimizu, Hidekazu Sekine, Katsuhisa Sakaguchi, Shinya Ogura, Kiyotaka Iwasaki, Masayuki Yamato, Mitsuo Umezu, Teruo Okano

termis 183 2010.09
Silicone vascular models for analysis of cardio artery stenting

Yoshihiro Okamoto, Hajime Inukai, Hiroyuki Kobashi, Hiroo Yamaga, Takanobu Yagi, Kiyotaka Iwasaki, Robert Shiurba, Mitsuo Umezu

6th world congress of biomechanics Abstracts 268 2010.08
Silicone vascular models for analysis of cardio artery stenting

Yoshihiro Okamoto, Hajime Inukai, Hiroyuki Kobashi, Hiroo Yamaga, Takanobu Yagi, Kiyotaka Iwasaki, Robert Shiurba, Mitsuo Umezu

6th world congress of biomechanics Abstracts 268 2010.08 [Refereed]
非臨床評価の確立による先進医療実現の加速化に関する医工学的研究

梅津光生

早稲田大学理工学研究所創設70周年記念誌, 早稲田大学理工学研究所 146 - 147 2010.07
医工融合に基づく先進医療研究の展開

岩崎清隆, 梅津光生

可視化情報 30 ( 1 ) 3 - 6 2010.07
Bloody Engineer の医療への挑戦

梅津光生

人工臓器 39 ( 1 ) 9 - 11 2010.06

CiNii
Near-wall flow mapping by fluorescent stereo-PIV in an elastic replica of human cerebral aneurysm

T.Yagi, A.Sato, M.Shinke, S.Takahashi, M.Umezu, H.Takao, Y.Murayama

The 14th International Symposium on Flow Visualization Program and Abstract book 65 2010.06
An automatic image segmentation method assisting for endovascular stent-grafting

C Hsu, M Uematsu, Y Nakano, R Sakamoto, M Umezu, T Azuma, S Aomi, R nakamura, T Suzuki, Y Muragaki, H Iseki

生体医工学 48 FC 2010.06
Error measurements for tissue thickness on an anatomical landmark point-based registration

R Sakamoto, M Uematsu, Y Nakano, C Hsu, M Umezu, H Iimura, S Aomi, R Nakamura, T Suzuki, Y Muragaki, H Iseki

生体医工学 48 FC 2010.06
An anatomical landmark point-based registration using tissue thickness correction based on Bayesian estimation

M Uematsu, Y Nakano, C Hsu, R Sakamoto, M Umezu, S Aomi, R Nakamura, T Suzuki, Y Muragaki, H Iseki

生体医工学 48 FC 2010.06
How to Get the Most Effective Knack to Promote an Interdisciplinary Collaboration

UMEZU Mitsuo

20 ( 1 ) 37 - 40 2010.05

CiNii
ツインズにおけるエンジニアの先進医療への挑戦 Another EBM(Engineering Based Medicine)

梅津光生

第3回システム疾患生命科学による先端医療技術開発シンポジウム 20 - 21 2010.03
早稲田大学の先進医療への挑戦

梅津光生

東京都23区稲門会支部大会2010 2010.03
コラーゲンゲル内微小血管網の組織学的評価(第9回日本再生医療学会総会,2010.3(広島)ベストポスター賞受賞

洞口重人, 清水達也, 小倉伸也, 野口慎介, 坂口勝久, 関根秀一, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

再生医療,日本再生医療学会雑誌 9 282 2010.03
診断情報誘導下脳腫瘍精密レーザ手術ロボットシステムにおける座標系統合法の開発と評価

中村亮一, 原美紀子, 大森繁, 植松美幸, 梅津光生, 村垣善浩, 伊関洋

電気学会論文誌C 130 ( 3 ) 414 - 419 2010.03
Two Stenting at Coronary Artery Bifurcation Yields Slow-Flow Region at Carina: In vitro Pulsatile Flow Investigation Using Elastic 3-Dimensional Stenotic Bifurcated Artery Replica

Iwasaki, Kiyotaka, Yagi, Takanobu, Yamamoto, Tadashi, Yagishita, Yuichi, Shinke, Manabu, Noguchi, Yusuke, Takahashi, Sara, Umezu, Mitsuo

CIRCULATION 122 ( 21 ) 2010 [Refereed]
ナノメートルオーダのチタン表面粗さが血液適合性に与える影響の研究

堤俊二, 岩崎清隆, 東宮裕人, 宮本雄貴, 石原一彦, 梅津光生

第22回バイオエンジニアリング講演会講演論文集 77 2010.01
補助人工心臓駆動下における心壁挙動が左心室モデル内血流に及ぼす影響の検討

久米嶺, 楠瀬俊祐, 立田良太, 五十嵐利博, 八木高伸, 岩崎清隆, 山崎健二, 梅津光生

第22回バイオエンジニアリング講演会講演論文集 57 2010.01
工学的制御による人工心筋の血行力学的応答の基礎検討

佐藤優太, 梅津光生, 藤本哲男, 白石泰之, 三浦英和, 金野敏, 山家智之, 金子芳一, Telma Keiko Sugai, 矢部翔太, 西條芳文, 馬場敦, 本間大

第22回バイオエンジニアリング講演会講演論文集 58 2010.01
胸腹部手術ナビゲーションのための重み付き特徴点レジストレーション

中野喜隆, 植松美幸, 鈴木孝司, 中村亮一, 青見茂之, 伊関洋, 梅津光生

第22回バイオエンジニアリング講演会講演論文集 131 2010.01
ヒト細胞による三次元組織の構築

野口慎介, 清水達也, 洞口重人, 小倉伸也, 坂口勝久, 関根秀一, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

第22回バイオエンジニアリング講演会講演論文集 24 2010.01
OPCAB吻合手技訓練装置“BEAT-S1”の開発と臨床現場への展開

朴栄光, 牧野穂高, 新家学, 八木高伸, 浅野竜太, 津久井宏行, Robert L Kormos, 梅津光生

第22回バイオエンジニアリング講演会講演論文集 138 2010.01
破裂脳動脈瘤内の血流に関するマイクロスケール時空間解析:衝突ジェットによる乱流の発生

佐藤絢香, 八木高伸, 新家学, 高橋彩来, 梅津光生, 村山雄一, 高尾洋之

第22回バイオエンジニアリング講演会講演論文集 207 2010.01
組織無細胞化処理が心臓弁を構成する弁葉・血管壁・バルサルバ洞の細胞外マトリクス成分に及ぼす影響の検討

岩崎清隆, 吉田ふみ, 竹野豊, 太田友博, 川辺治樹, 土岐二郎, 尾崎重之, 梅津光生

第22回バイオエンジニアリング講演会講演論文集 251 2010.01
冠動脈狭窄病変モデルを用いた至適ステント拡張方式の検討

濱悠太朗, 岩崎清隆, 八木下雄一, 野口裕介, 山本匡, 梅津光生

第22回バイオエンジニアリング講演会講演論文集 332 2010.01
心臓の収縮・拡張に伴うヒト右冠動脈基部の屈曲変形環境下での5種類のステントの破損に関する加速耐久試験

岩崎清隆, 濱悠太朗, 山本匡, 坪内俊介, 八木下雄一, 野口裕介, 中下健, 梅津光生

第22回バイオエンジニアリング講演会講演論文集 333 2010.01
組織無細胞化技術を駆使した前十字靭帯再建組織の開発に関する基礎検討

太田友博, 岩崎清隆, 川辺治樹, 柴崎剛, 竹野豊, 尾崎重之, 梅津光生

第22回バイオエンジニアリング講演会講演論文集 268 2010.01
壁面衝突により座屈を伴い瞬時膜破壊に至る赤血球破壊のリアルタイム可視化計測

徳永夏子, 八木高伸, 秋元裕紀, 関裕子, 梅津光生

第22回バイオエンジニアリング講演会講演論文集 208 2010.01
医学部に行かなくても先端医療に挑戦できる道を教えます

梅津光生

第22回バイオエンジニアリング講演会講演論文集 5 2010.01
Hemodynamic simulation for congenital heart disease

J L liu, Y Qian, M Umezu, K Itatani, K Miyaji

Computational fluid dynamics,Book of abstracts 7th international conference on CFD in the minerals and process industries 51 2009.12
Bloody Engineer の医療への挑戦

梅津光生

人工臓器第47回日本人工臓器学会予稿集 38 ( 2 ) s - 6 2009.11
人工心臓を駆使した組織無細胞化技術による大動脈弁の再生と抗石灰化

岩崎清隆, 尾崎重之, 太田友博, 川辺治樹, 竹野豊, 吉田ふみ, 土岐二郎, 柴崎剛, 梅津光生

人工臓器第47回日本人工臓器学会予稿集 s - 60 2009.11
分散型小型人口心筋ユニットの開発

白石泰之, 金子芳一, 金野敏, Sugai Telma Keiko, 佐藤優太, 畑山容子, 西條芳文, 山田昭博, 望月修一, 細田眞悟, 馬場敦, 田中明, 森田紀代造, 山岸正明, 藤本哲男, 梅津光生, 山家智之, 田林晄一, 本間大

人工臓器第47回日本人工臓器学会予稿集 38 ( 2 ) s - 78 2009.11
形状記憶合金線維を用いた人工心筋による右心補助の検討

細田眞悟, 馬場敦, 吉野晴樹, 坂田亮, 佐藤優太, 梅津光生, 本間大, 森田紀代造, スガウアテルマ・ケイコ, 劉紅箭, 山家智之, 白石泰之

人工臓器第47回日本人工臓器学会予稿集 38 ( 2 ) s - 79 2009.11
新しい小児用動脈弁におけるBulging sinusの及ぼす影響の基礎検討

鈴木一郎, 矢部翔太, Sugai Telma Keiko, 西條芳文, 白石泰之, 山家智之, 中村孝夫, 岡本吉弘, 田中隆, 梅津光生, 宮崎隆子, 山岸正明

人工臓器第47回日本人工臓器学会予稿集 38 ( 2 ) s - 135 2009.11
小児用ePTFE製肺動脈心臓代用弁の評価用シミュレーションシステム開発と基礎特性

矢部翔太, 鈴木一郎, Sugai Telma Keiko, 三浦英和, 金野敏, 劉紅箭, 白石泰之, 西條芳文, 山家智之, 宮崎隆子, 山岸正明, 田中隆, 梅津光生

人工臓器第47回日本人工臓器学会予稿集 38 ( 2 ) s - 135 2009.11
高速リアルタイムイメージングによる壁面衝突する赤血球の衝撃・破壊解析

八木高伸, 徳永夏子, 秋元祐紀, 関裕子, 梅津光生

人工臓器第47回日本人工臓器学会予稿集 38 ( 2 ) s - 136 2009.11
補助人工心臓駆動下における左心室内の血流の検討〜in vitro試験による血流の可視化実験

五十嵐利博, 石澤祐馬, 久米嶺, 楠瀬俊祐, 立田良太, 八木高伸, 岩崎清隆, 銭逸, 山崎健二, 梅津光生

人工臓器第47回日本人工臓器学会予稿集 38 ( 2 ) s - 150 2009.11
微小流路付きコラーゲンゲル培養床に用いた三次元心筋組織構築の検討

坂口勝久, 清水達也, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

人工臓器第47回日本人工臓器学会予稿集 38 ( 2 ) s - 154 2009.11
Viscoelastic characteristics of contracted collagen gels populated with fibroblasts or cardiomyocytes

馮忠剛, 瀬谷大貴, 北嶋龍雄, 中村孝夫, 小沢田正, 梅津光生

人工臓器第47回日本人工臓器学会予稿集 38 ( 2 ) s - 111 2009.10
3次元心筋組織構築のためのバイオリアクターの開発

坂口勝久, 沢田里智, 清水達也, 岩崎清隆, 大和雅之, 梅津光生, 岡野光夫

ライフサポート学会 21 ( 3 ) 104 - 109 2009.09
Calibration System for Pulse Spectrophotometry Using a Double-Layer Pulsation Flow-Cell

M Oura, N Kobayashi, S Yamamori, S Takeda, K Iwasaki, M Umezu

31th Annual International Conference of the IEEE Engineering in Medicine and Biology Society 896 - 899 2009.09 [Refereed]
Single-cell real-time imaging of flow-induced hemolysis using high-speed microfluidic technology

T Yagi, S Wakasa, N Tokunaga, Y Akimoto, M Umezu

Medical Physics and biomedical engineering: 11th international congress of the IUPESM on CD=ROM 2009.09 [Refereed]
Computational risk analysis for predicting rupture of cerebral aneurysms

Hiroyuki Takao, Yuichi Murayama, Yi Qian, Toshihiro Ishibashi, Mitsuo Umezu, Toshiaki Abe

XIV world congress of neurological surgery・American association of neurological surgeons Oral presentation ( 1435 ) 2009.08
Collision dynamics of red blood cells using high-speed impinging microjets

Takanobu Yagi, Shotaro Wakasa, Natsuko Tokunaga, Yuki Akimoto, Mitsuo Umezu

Flucome 2009:10th International conference on fluid control measurements and visualization on CD=ROM 2009.08
3D volume visualization for vascular flow modeling using stereo PIV with fluorescent tracer particles

T Yagi, A Kamoda, A Sato, W Yang, M Umezu

The 8th international symposium on particle image velocimetry on CD=ROM 2009.08
臨床用補助人工心臓交換時の安全性に関する実験的研究

田中隆, 古里正光, 石澤祐馬, 伊藤一彦, 岩崎清隆, 銭逸, 梅津光生

体外循環技術 36 ( 2 ) 108 - 114 2009.06
再生・成長する大動脈弁の開発

岩崎清隆, 尾崎重之, 梅津光生

適応医学 13 ( 1 ) 18 2009.06
Quantitative rupture estimation for cerebral aneurysms

Y Qian, H Takao, Y Murayama, M Umezu

10th congress of the WFITN・Interventional neuroradiology 15 187 2009.06
Computational hemodynamic simulation for congenital heart disease surgery

Y Qian, A Avolio, M Umezu, K Itatani

Heart conference 2009 session 20 2009.05
:血流シミュレーション技術を用いて小児先天性心疾患手術最適評価 Optimal surgery for congrenital heart disease based on computational hemodynamic analysis

劉金龍, 銭逸, 梅津光生, 板谷慶一, 宮地鑑

日本機械学会関東支部第15期総会および総会講演会 20309 2009.03
東京女子医科大学-早稲田大学の医工連携の成果例 -体内埋込型補助人工心臓(EVAHEART)の開発と臨床応用-

梅津光生

東京女子医科大学雑誌、第79巻第3号、pp90-95、2009.3 79 ( 3 ) 90 - 95 2009.03
ティッシュエンジニアリングによる心筋再生医療の現状と展望

坂口勝久, 清水達也, 梅津光生, 岡野光夫

東京女子医科大学雑誌 79 ( 3 ) 108 - 112 2009.03
ティッシュエンジニアリングによる心筋再生医療の現状と展望

坂口勝久, 清水達也, 梅津光生, 岡野光夫

東京女子医大誌 79 ( 3 ) 108 - 112 2009.03
早稲田大学と東京女子医科大学の連携-TWInsの創設と運営-

梅津光生

IDE現代の高等教育大学間連携 508 15 - 20 2009.02
僧帽弁シミュレーション実験と冠動脈吻合訓練

梅津光生, 朴栄光

Circulation up-to-Date、メディカ出版 4 ( 1 ) 15 - 21 2009.02
LVAS将来の夢医療機器産業としてどう定着させるか

梅津光生

第37回人工心臓と補助循環懇話会人工心臓が未来を拓く新しい重症心不全治療 2009.02
血漿タンパク質程度の大きさの表面粗さが抗血栓性に及ぼす影響

岩崎清隆, 堤俊二, 東宮裕人, 佐藤瑞, 梅津光生

第37回人工心臓と補助循環懇話会人工心臓が未来を拓く新しい重症心不全治療 31 2009.02
高速マイクロジェットを用いた赤血球の壁面衝突特性と破壊現象に関する検討

秋元祐紀, 八木高伸, 若狭翔太郎, 徳永夏子, 梅津光生

第37回人工心臓と補助循環懇話会人工心臓が未来を拓く新しい重症心不全治療 32 2009.02
大血管手術の安全性を高める画像支援ナビゲーションシステム

植松美幸, 中野善隆, 松川絋大, 宇都宮隆平, 中村亮一, 村垣善浩, 伊関洋, 青見茂之, 梅津光生

日本ヴァーチャルリアリティ学会論文誌TVRSJ 14 ( 1 ) 39 - 48 2009
Four-dimensional time-depended estimation for the rupturing process of ICA aneurysm

Yi Qoan, Hiriyuki Takao, Koichi Fukui, Mitsuo Umezu, Yuichi Murayama

international stroke conference 2009 [Refereed]
僧帽弁シミュレーション実験と冠動脈吻合訓練

梅津光生, 朴栄光

Circulation up to date、メディカ出版 4 ( 1 ) 15 - 19 2009.01
心臓血管外科領域における小口径溝型シリコン製ドレーンチューブの吸引能に対する実験的検討

田畑美弥子, 梅津光生, 落雅美, 清水一雄

日本医科大学医学会雑誌 4 ( 2 ) 88 - 95 2008.12
A surgical training simulator for quantitative assessment of the anastomotic technique of coronary artery bypass grafting

Y Park, M Shinke, N Kanemitsu, T Yagi, T Azuma, Y Shiraishi, R Kormos, M Umezu

The 13th International Conference Biomedical Engineering program and abstracts 108 2008.12 [Refereed]
Development of evaluation test method for the possibility of central venous catheter perforation caused by the insertion angle of a guidewire and dilator

M Uematsu, M Arita, K Iwasaki, T Tanaka, T Ohta, M Umezu,T Tuchiya

The 13th International Conference Biomedical Engineering program and abstracts 114 - 115 2008.12 [Refereed]
Development of a navigation system included correction method of anatomical deformation for aortic surgery

Matsukawa, M Uematsu, Y Nakano, R Utsunomiya, S Aomi, H Iimura, R Nakamura, Y Muragaki, H Iseki, M Umezu

The 13th International Conference Biomedical Engineering program and abstracts 131 2008.12 [Refereed]
Successful reproduction of In-Vitro fracture of an endovascular stent in superficial femoral artery utilizing a novel multi-loading durability test system

K Iwasaki, S Tsubouchi, Y Hama, M Umezu

The 13th International Conference Biomedical Engineering program and abstracts 131 - 132 2008.12 [Refereed]
Bioengineering advances and cutting-edge technology

M Umezu

The 13th International Conference Biomedical Engineering program and abstracts 138 2008.12 [Refereed]
New challenge for studying flow-induced blood damage : macroscale modeling and microscale verification

T Yagi, S Wakasa, N Tokunaga, Y Akimoto, T Akutsu, K Iwasaki, M Umezu

The 13th International Conference Biomedical Engineering program and abstracts 138 2008.12 [Refereed]
Microscale visualization of erythrocyte deformation by colliding with a rigid sueface using a high-speed impinging jet

S Wakasa, T Yagi, Y Akimoto, N Tokunaga, K Iwasaki, M Umezu

The 13th International Conference Biomedical Engineering program and abstracts 138 - 139 2008.12 [Refereed]
Biomedical engineering analysis of the rupture risk of cerebral aneurysms:

A Kamoda, T Yagi, A Sato, Y Qian, K Iwasaki, M Umezu, T Akutsu, T Takao, Y Murayama

The 13th International Conference Biomedical Engineering program and abstracts 143 2008.12
First trial of the chronic animal examination of the artificial myocardial function

Y Shiraishi, T Yambe, Y Saijo, K Matsue, M Shibata, H Liu, T Sugai, A Tanaka, S Konno, H Song, A Baba, K Imachi, M Yoshizawa, S Nitta, H Sasada, K Tabayashi, R Sakata, Y Sato, M Umezu, D Homma

The 13th International Conference Biomedical Engineering program and abstracts 153 2008.12 [Refereed]
In-vitro evaluation method to measure the radial force of various stents

Y Okamoto, T Tanaka, H Kobashi, K Iwasaki, M umezu

The 13th International Conference Biomedical Engineering program and abstracts 181 2008.12 [Refereed]
Preliminary study on interactive control for the artificial myocardium by shape memory alloy fibre

R Sakata, Y Shiraishi, Y Sato, Y Saijo, T Yambe, Y Luo, D Jung, A Baba, M yoshizawa, A Tanaka, T K Sugal, F Sato, M Umezu, S Nitta, T Fujimoto, D Homma

The 13th International Conference Biomedical Engineering program and abstracts 189 2008.12 [Refereed]
Fabrication of three dimensional tissues with perfused microchannels

K Sakaguchi, T Shimizu, K Iwasaki, M Yamato, M Umezu, T Okano

The 13th International Conference Biomedical Engineering program and abstracts 192 2008.12 [Refereed]
Angioguard XPの回収能力の実験的検討

田中智美, 山家弘雄, 岡本吉弘, 小橋宏行, 岩崎清隆, 梅津光生, 寺田友昭, 板倉徹

第24回日本脳神経血管内治療学会総会プログラム抄録 2 ( 4 ) 262 2008.11
血流シミュレーション技術を用いた破裂脳動脈瘤の形状的要素の検討

北谷優太郎, 高尾洋之, 銭逸, 福井弘一, 石橋敏寛, 村山雄一, 梅津光生

第24回日本脳神経血管内治療学会総会プログラム抄録 2 ( 4 ) 295 2008.11
内頚動脈に発症したSidewall型の脳動脈瘤の血流学的分類-in vitro可視化実験による破裂3症例と未破裂6症例の比較検討

鴨田明憲, 八木高伸, 佐藤絢香, 銭逸, 岩崎清隆, 阿久津敏之介, 梅津光生, 高尾洋之, 村山雄一

24回日本脳神経血管内治療学会総会プログラム抄録 2 ( 4 ) 296 2008.11
ブタ頚動脈の力学的特性の検討、第24回日本脳神経血管内治療学会総会

岡本吉弘, 山家弘雄, 田中智美, 小橋宏行, 岩崎清隆, 梅津光生, 寺田友昭, 板倉徹

第24回日本脳神経血管内治療学会総会プログラム抄録 2 ( 4 ) 296 2008.11
硬さを合わせた内頚動脈狭窄血管モデルの製作及び異種・異径ステント留置の評価

山家弘雄, 岡本吉弘, 田中智美, 小橋宏行, 岩崎清隆, 梅津光生, 寺田友昭, 板倉徹

第24回日本脳神経血管内治療学会総会プログラム抄録 2 ( 4 ) 297 2008.11
新しい拡張力測定試験装置を用いた各種ステントの特性評価

小橋宏行, 山家弘雄, 岡本吉弘, 田中智美, 岩崎清隆, 梅津光生, 寺田友昭, 板倉徹

第24回日本脳神経血管内治療学会総会プログラム抄録 2 ( 4 ) 262 2008.11
IABP駆動装置を用いたSV Pump補助人工心臓システムの拍出性能評価

久米嶺, 古里正光, 石澤祐馬, 白石泰之, 岩崎清隆, 梅津光生

人工臓器vol.37 no.2第46回日本人工臓器学会大会予稿集 37 ( 2 ) 75 2008.11
無細胞化技術及び拍動バイオリアクター培養技術による心臓弁再生

岩崎清隆, 尾崎重之, 大関泰宏, 林田恭子, 山口晋平, 安田稔, 大庭幸裕, 太田友博, 天野みなみ, 梅津光生

人工臓器vol.37 no.2第46回日本人工臓器学会大会予稿集 79 2008.11
グルタールアルデハイド処理ヒト心膜に関する検討

山下裕正, 岩崎清隆, 尾崎重之, 林田恭子, 大関泰宏, 内田真, 梅津光生

人工臓器vol.37 no.2第46回日本人工臓器学会大会予稿集 87 2008.11
人工心筋の選択的な収縮支援メカニズムと駆動制御系の開発

坂田亮, 白石泰之, 佐藤優太, 山家智之, 梅津光生, 金野敏, 西條芳文, Telma Keiko Sugai, 吉澤誠, 藤本哲男, 馬場敦, 本間大

人工臓器vol.37 no.2第46回日本人工臓器学会大会予稿集 101 2008.11
左心補助循環用拡張型カニューラの開発

藪下祐樹, 中野壮陛, 藤本哲男, 壁井信之, 梅津光生

人工臓器vol.37 no.2第46回日本人工臓器学会大会予稿集 102 2008.11
末梢血管における複合負荷を模擬した加速耐久試験装置によるステントの破損形態の評価

坪内俊介, 岩崎清隆, 錦織晃, 濱悠太朗, 梅津光生

第46回日本人工臓器学会大会予稿集 115 2008.11
頚動脈に対するガイドワイヤ及びダイレータの挿入角度による血管穿孔可能性を評価する試験法の構築

植松美幸, 有田誠, 岩崎清隆, 田中隆, 太田友博, 梅津光生, 土屋利江

第46回日本人工臓器学会大会予稿集 141 2008.11
コーティング材料の異なる拍動ポンプのIn-vito拍動流抗血栓性試験における凝固因子の比較評価

岩崎清隆, 中安妙子, 堤俊二, 前野直邦, 梅津光生, コーティング材料の異なる拍動ポンプのIn-vito拍動流抗血栓性試験における凝固因子の比較評価

第46回日本人工臓器学会大会予稿集 148 2008.11
人工臓器における圧力測定のための新規的な小型圧力センサーの開発

秋山真己, 藤本哲男, 中野壮陛, 竹花良人, 梅津光生

第46回日本人工臓器学会大会予稿集 168 2008.11
Optimal surgery for congenital heart disease based on computational hemodynamic analysis

Y Qian, J L Liu, M Umezu, K Itatani

The 4th Joint Symposium Shanghai Jiao Tong University and Waseda University 2008.10
Introduction of our new institution:TWIns managed by two universities

Mitsuo Umezu, Itsu Sen, Kiyotaka Iwasaki, Kenji Yamazaki, Teruo Okano

The 4th Joint Symposium Shanghai Jiao Tong University and Waseda University 2008.10
長期使用補助人工心臓交換時の安全性に関する実験的研究-接続強度の経時的変化

田中隆, 石澤祐馬, 岩崎清隆, 梅津光生, 五十嵐利博

体外循環技術第34回大会日程・抄録特集号 35 ( 3 ) 291 2008.10
低価格人工心臓を医療の安全・安心のためのツールとして使う医工学発展型研究

梅津光生, 岩崎清隆, 加瀬川均, 伊関洋, 銭逸, 石井裕之

ASMeW Interbatuinal Symposium 17 2008.10
運動機能を支える再生促進型移植用組織(心臓弁・靭帯・心膜)の開発研究

岩崎清隆, 梅津光生, 尾崎重之, 加瀬川均, Charles Vacanti, 小島宏司, 小玉正太

ASMeW Interbatuinal Symposium 47 2008.10
慢性動物試験のための人工信金の改良

佐藤優太, 白石泰之, 坂田亮, 林輝, 田中隆, 梅津光生, 金野敏, 西条芳文, Terma Sugai Keiko, 吉澤誠, 山家智之, 馬場敦, 増本憲泰, 藤本哲男, 本間大

福祉工学シンポジウム2008講演論文集 2008.10
大血管ナビゲーションにおけるベッドの動きを補償するマーカーシステムの開発

中野善隆, 植松美幸, 松川絃大, 宇都宮隆平, 中村亮一, 村垣善浩, 伊関洋, 青見茂之, 梅津光生

第7回日本コンピュータ外科学会会誌 309 2008.10
胸部領域ナビゲーションにおける術中体位の変化を考慮した骨格変形補正法

松川絃大, 植松美幸, 中野善隆, 宇都宮隆平, 青見茂之, 飯村浩, 中村亮一, 村垣善浩, 伊関洋, 梅津光生

第7回日本コンピュータ外科学会会誌 395 2008.10
Tissue engineering artery utilizing the physiologic pulsatile bioreactor

K Iwasaki, K Kojima, S Kodama, C A Paz, M Umezu, C A Vacanti

The international journal of artificial organs 31 ( 7 ) 584 2008.09
Functional examination of an artificial myocardium with shape memory alloy fibre in chronic animal experiment

Y Shiraishi, T Yambe, R Sakata, T Sugai, M Uematsu, Y Park, Y Saijo, A Baba, M Yoshizawa, K Imachi, T Fujimoto, M Umezu, D Homma

The international journal of artificial organs 31 ( 7 ) 598 2008.09
Microfludic analysis of erythrocyte deformation for studying flow-induced hemolysis

T Yagi, H Sudo, Y Akimoto, M Umezu

The international journal of artificial organs 31 ( 7 ) 603 2008.09
miniature-sized sensor for measuring pressure distribution in artificial organs

M Akiyama, T Fujimoto, S Nakano, Y Takehana, M Umezu

The international journal of artificial organs 31 ( 7 ) 602 2008.09
In-vitro experimental evaluation of flow performance of three vena cava filters

Y Qian, J Liu, Y Liu, Z Cao, M Umezu, S Ariyama

The international journal of artificial organs 641 2008.09
Development of a newly designed tube for aortic cannula in the ventricular assist system

Y Yabushita, S Nakano, T Fujimoto, N Kabei, M Umezu

The international journal of artificial organs 31 ( 7 ) 2008.09
A novel multi-loading accelerated durability test system for peripheral vascular stents

K Iwasaki, S Tsubouchi, Y Hama, A Nishikohri, M Umezu

The international journal of artificial organs 31 ( 7 ) 625 2008.09
Optimization oh a mechanical property of stenotic carotid artery model for in vitro practical test stenting

Y Okamoto, H Yamaga, T Tanaka, H Kobashi, T Terada, T Itakura, K Iwasaki, M Umezu

The international journal of artificial organs 31 ( 7 ) 626 2008.09
もうひとつのEBM Engineering based medicine

梅津光生

日本医事新報 4405 ( 4405 ) 1 - 1 2008.09

CiNii
Bioengineered three layered robust and elastic artery using hemodynamically-equivalent pulsatile bioreactor

Kiyotaka Iwasaki, Koji Kojima, Shohta Kodama, Ana C Paz, Melody Chambers, Mitsuo Umezu, Charles a Vacanti

American heart association 118 s52 - s57 2008.09 [Refereed]
JSAO highlights from the Japanese Society for Artificial Organs(Affiliated society symposium)

Mitsuo Umezu

28 2008.09
東京女子医大-早大の医工学連携の成果例:遠心式補助人工心臓エバハートの開発と臨床応用

梅津光生

第74階東京女子医科大学学会総会シンポジウムプログラム 2 2008.09
佐藤優太、白石泰之、坂田亮、林輝、田中隆、梅津光生、金野敏、西條芳文、吉澤誠、山家智之、馬場敦、増本憲泰、藤本哲男、本間大

Improvement of the artificial myocardial, assistance for chronic animal experiment

福祉工学シンポジウム2008講演論文集 135 - 136 2008.09
血液循環系の模擬循環システム-フルードパワー技術の医工学的利用-

白石泰之, 梅津光生

油空圧技術 47 ( 8 ) 12 - 16 2008.08

CiNii
本邦初の次世代型補助人工心臓EVAHEART-自宅療養・就労復帰が可能となった-

山崎健二, 梅津光生, 太田英輔, 富岡淳, 岩崎清隆, 石原一彦

油空圧技術 47 ( 8 ) 17 - 21 2008.08
Development of a Compact Mock Circulation System and a New Flow-Cell Model for Pulse Spectrophotometry

M. Oura, N. Kobayashi, S. Takeda, K. Iwasaki, M. Umezu

30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society 670 - 673 2008.08 [Refereed]
Engineering decellularized tissues ( Heart valve, ligament and pericardium) guiding regeneration to improve motility

Kiyotaka Iwasaki, Mitsuo Umezu, Shigeyuki Ozaki, Hitoshi Kasegawa, Charles A Vacanti, Koji Kojima, Shota Kodama

ASMeW InternationalSymposium Realizing high quality of life and extension of hearth life expectancy 24 2008.08
In-vitro study of the 3D vertical flow structure in the sinus of Valsalva using Multiplane scanning stereo PIV: implication for coronary circulation

Takanobu Yagi, William Yang, Shotaro Wakasa, Mitsuo Umezu

International Symposium Flow Visualization 13 ISFV13 72 2008.07
心臓血管外科領域における小口径溝型シリコン製ドレーンチューブの吸引能に対する実験的検討従来型胸腔ドレーンチューブとの比較

田畑美弥子, 梅津光生, 落雅美, 清水一雄

日本医科大学医学会雑誌 4 ( 2 ) 88 - 95 2008.07
Is there any possibility that heart transplantation can be replaced by an artificial heart?

M Umezu,K Iwasaki, Y Qian,T Yagi, K Yamazaki

6th international conference of the international society for gerontechnology,final program 228 2008.06
Characterization of flow dynamics in intracranial cerebral aneurysm using in vitro modeling techniques

T Yagi, Y Qian, M Fukushima, A Kamoda,A Sato, K Iwasaki, M Umezu, H Takao, Y Murayama

6th international conference of the international society for gerontechnology,final program 242 2008.06
New challenge to estimate the rupture process of ICA aneurysm,

K Fukui, Y Qian, M Umezu, H Takao,T Ishibashi, Y Murayama

American society of neuroradiology 2008 , 2008 proceedings 87 2008.06
Computation estimation of internal pressure variation inMCA aneurysms

Yi Qian, Hiroyuki Takao, Koichi Fukui, Mitsuo Umezu, Toshihiro Ishibashi, Yuichi Murayama

ANNS 2008 Cicago annual meeting 2008.04
マイクロジェットを用いた高速流動する個々の赤血球の衝突解析

八木高伸, 須藤宏幸, 梅津光生

第36回人工心臓と補助循環懇話会抄録集 32 2008.03
梅津光生脱細胞ウシ心膜の組織学的特性及び力学的特性に関する検討

山口晋平, 岩﨑清隆, 佐竹祥明, 安田稔, 大庭幸裕

再生医療・第7階日本再生医療学会総会抄録、2008 vol.7増刊号 7 277 2008.03
人工臓器開発の経験を駆使した再生医療基盤技術の開発

岩﨑清隆, 尾崎重之, 山口晋平, 安田稔, 大庭幸裕, 大関泰宏, 林田恭子, 太田友博, 天野みなみ, 梅津光生

第36回人工心臓と補助循環懇話会抄録集 79 2008.03
機械式人工心筋の構造と機能の設計

白石泰之, 西條芳文, 山家智之, 末永健, 柴田宗一, 山口済, 馬場敦, 井街宏, 和田由美子, 坂田亮, 渡部智樹, 土岐二郎, Telma Sugai Keiko, 吉澤誠, 田中明, 藤本哲男, 梅津光生, 本間大, 佐々田比呂志, 仁田新一, 田林晄一

第36回人工心臓と補助循環懇話会抄録集 33 2008.03
Fabrication of 3-D myocardial tissues with perfused microchannels

Sakaguchi Katsuhisa, Shimizu Tatsuya, Umezu Mitsuo, Okano Teruo

814 2008.02
1施設1台:富山の常備薬型補助人工心臓の実用化

梅津光生

平成19年度厚生労働科学研究費研究成果等普及啓発事業医療機器開発推進研究身体機能解析・補助・代替機器開発研究成果発表会要旨集 1 - 2 2008.02
A study on a newly designed aortofemoral prosthetic Y graft

T. Fujimoto, S. Nakano, H. Iwamura, Y. Shiraishi, T. Yambe, M. Umezu

BIOCYBERNETICS AND BIOMEDICAL ENGINEERING 28 ( 1 ) 59 - 63 2008 [Refereed]

　View Summary

Aortofemoral prosthetic Y grafts are applied for treating abdominal aortic aneurysms. In this study, experiments were conducted in order to demonstrate the effects of an incremental increase in branch diameter in a newly designed aortofemoral Y graft under conditions of both steady and pulsatile flow conditions. It was revealed that in Y grafts, the incremental increase by only 4 mm in the branch diameter affects hydrodynamic characteristics drastically under conditions of both steady and pulsatile flow conditions.
循環器系における医用機械工学の最新研究動向について(講演・第3回メディカルテキスタイルの開発に関する研究会・名古屋)

梅津光生

2007.12
Development of a navigation system for aortic surgery: System evaluation based on clinical trials

Miyuki Uematsu, Ryoichi Nakamura, Yoshihiro Muragaki, Hiroshi Iseki, Mikiko Hara, Kodai Matsukawa, Yoshitaka Nakano, Mitsuo Umezu, Shigeyuki Aomi, Noriko Nishi, Hiroshi Iimura, Hiroshi Fujimoto

3rd Asia conference on computer aided surgery 11 2007.12
Development of an image-guided system for robotic laser surgery

M Hara, R Nakamura, S Omori, Y Muragaki, M Uematsu, K Matsukawa, Y Nakano, H Iseki, M Umezu

3rd Asia conference on computer aided surgery 23 2007.12
Domesutic and foreign trends in the prevalence of heart failure and the necessity of next-generation artificial hearts: a survey by the Working Group on Establishment of Assessment Guidelines for Next-Generation Artificial Heart Systems

Eisuke Tatsumi, Takeshi Nakatani, Kou Imachi, Mitsuo Umezu, Shun-ei Kyo, Kazuhiro sase, Setsuo Takatani, Hikaru Matsuda

Domesutic and foreign trends in the prevalence of heart failure and the necessity of next-generation artificial hearts: a survey by the Working Group on Establishment of Assessment Guidelines for Next-Generation Artificial Heart Systems 10 ( 4 ) 187 - 194 2007.12 [Refereed]
Present status of sophisticated durability testing for EVAHEART

Mitsuo Umezu, Tomoya Kitano, Toshimasa Tokuno, Mikio Kuge, Shun-ichi Yanazaki, Kenji Yamazaki

International society for rotary blood pumps, congress program and abstract booklet 89 - 90 2007.11
大血管ナビゲーションの臨床利用経験に基づくレジストレーション点配置の最適化

植松美幸, 原美紀子, 松川絋大, 中野喜隆, 中村亮一, 村垣善浩, 伊関洋, 青見茂之, 梅津光生, 藤本浩志

第16回日本コンピュータ外科学会大会・第17回コンピュータ支援画像診断学会大会、合同論文集 151 - 152 2007.11
冠動脈バイパス手術における血管吻合手技の定量かに向けた基礎検討

沖恵理子, 朴栄光, 金光直彦, 白石泰之, 東隆, 大坪真也, 岩﨑清隆, 梅津光生

第16回日本コンピュータ外科学会大会・第17回コンピュータ支援画像診断学会大会、合同論文集 83 - 84 2007.11
大血管ナビゲーションの上体捻転性の影響に関する報告

松川絋大, 植松美幸, 原美紀子, 中野喜隆, 中村亮一, 村垣善浩, 伊関洋, 青見茂之, 梅津光生

第16回日本コンピュータ外科学会大会・第17回コンピュータ支援画像診断学会大会、合同論文集 127 - 128 2007.11
Ventrassist (TM) blood pump internal flow visualization stydy using CFD techniques introduction

Yi Qian, Mitsuo Umezu, Martin Cook, John Woodard

15th congress of the ISRBP, International society for rotary blood pumps, congress program and abstract booklet 2007.11
中大動脈瘤のCFDを用いた血流比変化における動脈瘤内圧変化の検討

高尾洋之, 村山雄一, 福井孝一, 銭逸, 石橋敏寛, 北谷優太郎, 八木高伸, 岩﨑清隆, 梅津光生, 阿部俊昭

第23回NPO法人日本脳神経血管内治療学会総会(JNET) 1 ( 2 ) 179 2007.11
実形状・弾性モデルを用いた脳動脈瘤内の流れのリアルタイム解析・破裂瘤と未破裂瘤の流入形態の比較検討

福島桃子, 岩﨑清隆, 八木高伸, 鴨田明憲, 佐藤絢香, 梅津光生, 阿久津敏之介, 高尾洋之, 石橋敏寛, 村山雄一

第23回NPO法人日本脳神経血管内治療学会総会(JNET) 2 ( 1 ) 140 2007.11
シミュレーション技術を用いた脳動脈瘤破裂要因の検討

福井弘一, 高尾洋之, 銭逸, 北谷優太郎, 岩﨑清隆, 石橋敏寛, 村山雄一, 梅津光生

第23回NPO法人日本脳神経血管内治療学会総会(JNET) 2 ( 1 ) 140 2007.11
自己拡張型ステントの拡張力の温度依存性評価

岡本吉弘, 山家弘雄, 小橋宏行, 田中智美, 矢田裕紀, 岩﨑清隆, 寺田友昭, 板倉徹

第23回NPO法人日本脳神経血管内治療学会総会(JNET) 1 ( 2 ) 223 2007.11
各ステントの構造の構造の違いがもたらす留置後のステント形状の検討

田中智美, 山家弘雄, 岡本吉弘, 矢田裕紀, 小橋宏行, 岩﨑清隆, 梅津光生, 寺田友昭, 板倉徹

第23回NPO法人日本脳神経血管内治療学会総会(JNET) 1 ( 2 ) 223 2007.11
新しい内頸動脈狭窄血管シリコンモデルに対する検討

山家弘雄, 岡本吉弘, 田中智美, 小橋宏行, 矢田裕紀, 岩﨑清隆, 梅津光生, 寺田友昭, 板倉徹

第23回NPO法人日本脳神経血管内治療学会総会(JNET) 1 ( 2 ) 223 2007.11
真の医工連携の実践・機械工学が先進医療に挑戦する(医療福祉機器研修会講演)

梅津光生

2007.11
日本体外循環技術医学学会会員への期待研究にどうアプローチするか?(第33回日本体外循環技術医学会大会講演)

梅津光生

2007.11
量産向け旋回渦流型人工心臓内面検査装置の開発

田中隆, 古里正光, 石澤祐馬, 伊藤一彦, 岩﨑清隆, 梅津光生

第5回生活支援工学系学会連合大会、講演予稿集、日本生活支援工学会 24 2007.10
How to ensure a safety exchange of ventricular assist device (VAD) for the long term usage

T Tanaka, T Shima, M Furusato, Y Kokuzawa, K Ito, K Iwasaki, Y Qian, M Umezu

人工臓器第45回日本人工臓器学会大会予稿集 s74 2007.10
Development of an anatomically identical silicone carotid bifurcation model with artificial plaque and its application for stenting technique

Y Okamoto, H Yamaga, H Yada, T Tanaka, H Kobashi, T Terada, T Itakura, K Iwasaki, m Umezu

人工臓器 36 ( 2 ) s - 98 2007.10
東洋紡績社製補助心臓の臨床使用後の経時的変化について〜血液ポンプ交換の指針の確立に向けて〜

五十嵐利博, 西中智博, 斎藤聡, 川合明彦, 黒澤博身, 岩﨑清隆, 田中隆, 伊藤一彦, 島智宏, 古里正光, 石澤祐馬, 五十嵐太郎, 梅津光生

人工臓器 36 ( 1 ) s - 62 2007.10
Structural engineering design for a sophisticated artificial myocardium using shape memory alloy fiber

Y Wada, Y Shiraishi, T Watabe, R Sakata, M Uematsu, Y Park, T Tanaka, Y Saijo, T Yambe, D Homma, M Umezu

人工臓器 36 ( 2 ) s - 19 2007.10
In vitro comparative analysis of 3D flow fields in models of valved graft: implication of neosinus

S Wakasa, T Yagi, H Sudo, N Tokunaga, W Yang Ph.D, M Umezu, Ph.D, MD, K Iwasaki Ph.D

人工臓器 36 ( 2 ) s - 22 2007.10
Three-dimensional volume characterization of swirling flow with fluid-structure coupling in a spiral voltex pulsatile pump

T Yagi, S Wakasa, W Yang, K Iwasaki, M Umezu

人工臓器 36 ( 2 ) s - 25 2007.10
Five years result of multi-institutional cooperative project to develop a totally implantable ventricular assist system

K Imachi, Y Abe, T Yambe, T matsuki, Y Mitamura, E Okamoto, M Umezu, I saijo, T Isoyama, Y shiraishi, A Baba, H Miura, Y Inoue, K Iwasaki, M Yoshizawa, I Nemoto

人工臓器 36 ( 2 ) s - 26 2007.10
In vitro quantitative assessment of thrombogenicity of a pulsatile ventricular assist device using the original circulation system

K Iwasaki, M Eguchi, T Nakayasu, K Ishihara, M Umezu

人工臓器 36 ( 2 ) s - 29 2007.10
Preliminary study on the restructuring of myocardium using shape memory alloy fibres

Y Shiraishi, Y Saijo, T Yambe, Y Wada, R Sakata, T Watabe, M Yoshizawa, A Tanaka, T Sugai, M Umezu, S Nitta, D Homma

人工臓器 36 ( 2 ) s - 32 2007.10
心室と心不全のメカニクスモデリングに基づく人工的心筋補助の試み

白石泰之, 山家智之, 西條芳文, 柴田宗一, 増田信也, 田林晄一, 梅津光生, 本間大

電気学会研究会資料 85 - 88 2007.10
Clinical trials for a safety thoracoabdominal aortic replacement using innovative robot technology

Mitsuo Umezu, Miyuki Uematsu, Shigeyuki Aomi, Ryoichi Nakamura, Hiroshi Iseki

人工臓器 36 ( 2 ) S - 32 2007.10
Analysis of mechanical characteristics of engineered cardiac tossue based upon the beating displacement

Zhoggang Feng, Mitsuo Umezu, Yasutomo Nomura, Tatsuo Kitajima, Takao Nakamura

Artificial Organs 31 ( 10 ) A66 2007.10
The muchanisum of turbulence: new finding of impulsively-generated compressive fluid mechanical stress on blood cells flowing through artificial heart halves

T Yagi, H Sudo, t Akutsu, K Iwasaki, M Umezu

Artificial Organs 31 ( 10 ) A69 2007.10
How to ensure a safety exchange of ventricular assist device(VAD) for the long term usage

T Tanaka, T Shima, M Furusato, Y Kokuzawa, K Ito, K Iwasaki, Y Qian, M Umezu

Artificial Organs 31 ( 10 ) A74 2007.10
Preliminary study on an optimal regulation of the artificial myocardium based on the fibrous control methodology of shape memory alloy

Y Shiraishi, Y Wada, R Sakata, T Watabe, Y Saijo, T Yambe, H Liu, A Baba, M Yoshizawa, A Tanaka, T Sugai, Y Kakubari, F Sato, M Umezu, S Nitta, T Fujimoto, D Homma

Artificial Organs 31 ( 10 ) A82 2007.10
Comparison of mRNA expression of transcriptional factors and intercalated disk constituent proteins between in vivo and cultured cardiomyocytes

Takao Nakamura, Zhonggang Feng, Tsumasa Honda, Yasutomo Nomura, Tatsuo Kitajima, Mitsuo Umezu

Artificial Organs 31 ( 10 ) A85 2007.10
Miniature-sized sensor for measuring pressure in blood pumps

T Fujimoto, y Tanaka, S Nakano, M Akiyama, S Nakamura, Y Takehana, M Umezu

Artificial Organs 31 ( 10 ) A86 2007.10
Practical in vitro blood compatibility testing of pulsatile pump

T Nakayasu, K Iwasaki, M Eguchi, N Kubo, K Ishihara, M Umezu

The international journal of artificial organs 30 ( 8 ) 691 2007.09
Development of an anatomically identical silicone carotid bifurcation model with artificial plaque and its application for stenting technique

Y Okamoto, H, Yamaga, H Yada, T Tanaka, H Kobashi, T Terada, T Itakura, k Iwasaki, Umezu

The international journal of artificial organs 30 ( 8 ) 726 2007.09
: Functional improvement of an newly-developed myocardial assist device using shape memory alloy fibres

Y Shiraishi, T Yambe, Y Saijo, K Matsue, H Liu, S Nitta, A Baba, K Imachi, Y Wada, R Sakata, T Tanaka, M Uematsu, Y Park, M Umezu, A Tanaka, M Yoshizawa, F Sato, T Fujimoto, H Sasada, K Tabayashi, D Hommma

The international journal of artificial organs 30 ( 8 ) 736 2007.09
Development of miniature-sized pressure sensor for implanting in artificial organs

T Fujimoto, Y Tanaka, S Nakano, M Akiyama, S Nakamura, Y Takehana, M Umezu

The international journal of artificial organs 30 ( 8 ) 744 2007.09
バイオエンジニアリング部門創設者故・土屋喜一先生を偲んで

梅津光生

Bioengineering news日本機械学会 36 2 2007.09
再生医療を支える最先端技術と将来への展望

梅津光生

実例から学ぶ再生医療研究の現状と将来展望、財団法人日本公定書協会薬時エキスパート研修会シリーズ5 25 - 32 2007.09
Tensile test to ensure a safety of cannula connection in clinical ventricular assist device(VAD)

Takashi Tanaka, Tomohiro Shima, Masateru Furusato, Yuma Kokuzawa, Kazuhiko Ito, Kiyotaka Iwasaki, Yi Qian, Mitsuo Umezu

Life system modeling and simulation,International conference LSMS 2007 546 - 662 2007.09 [Refereed]
A reproduction of inflow restriction in the mock circulatory system to evaluate a hydrodynamic performance of a ventricular assist device in practical conditions

Masateru Furusato, Tomohiro Shima, Yuma Kokuzawa, Kazuhiko Ito, Takashi Tanaka, Kiyotaka Iwasaki, Yi Qian, Mitsuo Umezu, ZhiKun Yan, Ling Zhu

Life system modeling and simulation,International conference LSMS 2007 553 - 558 2007.09 [Refereed]
How to ensuresafety factors in the development of artificial heart:verified by the usage of “Modeling and simulation” technology, Life system modeling and simulation

Mitsuo Umezu

Life system modeling and simulation,International conference LSMS 2007 88 - 96 2007.09 [Refereed]
医療機器の非臨床評価:Engineering Based Medicine(もう一つのEBM)(講演会)

梅津光生

テフーズドジャパン株式会社テュフインフォサービス 2007.09
Cerebral aneurysm rupture and unrupture risk factor analysis using computational fluid dynamics technique

Yi Qian, Koichi Fukui, Mitsuo Umezu, Hiroyuki Takao, Toshihiro Ishibashi, Yuichi Murayama

Interventional neuroradiology,Proceedings of the 9th congress of the world federation of interventional and therapeutic neuroradiology,Beijing China 387 2007.09
How to apply the rpbot technology to train cardiovascular surgeons OPCAB training system “YOUCAN” and ”BEAT”

Young Kwang Park, Yumiko Wada, Eriko Oki, Naohiko Kanemitsu, Yasuyuki Shiraishi, Takashi Azuma, Yousuke Ishii, Mitsuo Umezu

The 4th COE-CIR joint workshop Future collaborations on Robot technologies beiween Korea and Japan 73 2007.09
医工連携の重要性

梅津光生

Boston Scientific 2007.08
Quantitative evaluation for anastomotic technique of coronary artery bypass grafting by using In-vitro mock circulatory system

Young Park, Yutaka Mita, Eriko Oki, Naohiko Kanemitsu, Yasuyuki Shiraishi, Yousuke Ishii, Takashi Azuma, Masami Ochi, Mitsuo Umezu

29th Annual international conference of the IEEE engineeringf in mediccine and biology society 2007.08 [Refereed]
Educational lecture:small caliber coronary bypass graft learned from the history:new approaches by biomedical engineer

Mitsuo Umezu

JACAS The12th annual meeting of the Japanese Association Coronary Artery Surgery 84 2007.07
Establishment of integrated quantitative evaluation for surgical skills with in –vitro self-training system

Mitsuo Umezu, Young Kwang Park, Yitaka Mita, Eriko Oki

92nd ICB seminar 9th Polish-Japanese seminar on trends in development of new semsors and sensing systems for clinical diagnosis,Polska academia nauk MCB 20 2007.06
Present status undulation pump ventricular assist device and total artificial heart

Kou Imachi, Yusuke Abe, Itsuro Saito, Atsushi Baba, Tsuneo Chinzei, Tomoyuki Yambe, Yasuhiro Shiraishi, Hidekazu Miura, Hidetoshi Matsuki, Yoshinori Mitamura, Yusuke Inoue, Eiji Okamoto, Kiyotaka Iwasaki, Mitsuo Umezu

, 92nd ICB seminar 9th Polish-Japanese seminar on trends in development of new semsors and sensing systems for clinical diagnosis,Polska academia nauk MCB 34 2007.06
Newly-designed navigation system towards a safety of aortic vascular surgery:preliminary clinical experiences

M Uematsu, M Umezu, S Aomi, R Nakamura, Y Muragaki, H Iseki, H Fujimoto

92nd ICB seminar 9th Polish-Japanese seminar on trends in development of new semsors and sensing systems for clinical diagnosis,Polska academia nauk MCB 22 2007.06
Investigation of the connecting conditions between ventricular assist device (VAD) and cannula: a safety consideration

Takashi Tanaka, Tomohiro Shima, Masateru Furusato, Yuma Kokuzawa, Kazuhiko Ito, Kiyotaka Iwasaki, Mitsuo Umezu

92nd ICB seminar 9th Polish-Japanese seminar on trends in development of new semsors and sensing systems for clinical diagnosis,Polska academia nauk MCB 39 2007.06
Fem analysis of diaphragmatic movements in a spiral vortex blood pump

K Ito, T Shima, Y Kouno, M Furusato, T Tanaka, K Iwasaki, T Fujimoto, M Umezu

92nd ICB seminar 9th Polish-Japanese seminar on trends in development of new semsors and sensing systems for clinical diagnosis,Polska academia nauk MCB 40 2007.06
Development of miniature-sized sensor for measuring blood pressure

T Fujimoto, Y Tanaka, S Nakano, M Akiyama, S Nakamura, Y Takehana, M Umezu

92nd ICB seminar 9th Polish-Japanese seminar on trends in development of new semsors and sensing systems for clinical diagnosis,Polska academia nauk MCB 46 2007.06
外科手術訓練装置の開発によるDRYLAB拠点構築に向けた取り組み-冠動脈吻合手技訓練装置、縫合手技評価用訓練モデル-

朴栄光, 小椋優, 三田裕, 沖恵理子, 大島信希, 白石泰之, 竹村博文, 夜久均, 畠和幸, 高西淳夫, 梅津光生

モデル&シミュレーション医学教育研究会会報 1 23 - 27 2007.06
Characteristics of spiral vortex pump driven by two different drivers

K ITO, T SUDO, T SHIMA, Y KOUNO, Y OHNISHI, T TANAKA, K IWASAKI, T FUJIMOTO, M UMEZU

Biocybernetics and Biomedical Engineering, Polish Academy of Sciences Institute of Biocybernetics and Biomedical Engineering 27 ( 1/2 ) 121 - 132 2007.06
Japanese-made implantable centrifugal type ventricular assist system(LVAS):EVAHEART

Mituso UMEZU, Kenji YAMAZAKI, Shunichi YAMAZAKI, Kiyotaka IWASAKI, Takayuki MIYAKOSHI, Tomoya KITANO, Toshimasa TOKONO

Biocybernetics and Biomedical Engineering, Polish Academy of Sciences Institute of Biocybernetics and Biomedical Engineering 27 ( 1/2 ) 111 - 119 2007.06
In Memoriam of Prof.Kiichi Tsuchiya

Mitsuo UMEZU

Biocybernetics and Biomedical Engineering, Polish Academy of Sciences Institute of Biocybernetics and Biomedical Engineering 27 ( 1/2 ) 5 - 7 2007.06
国内外の心不全の同行と我が国における次世代型人工心臓の必要性について:次世代型高機能人工心臓審査ガイドラインワーキンググループからの提言

巽英介, 中谷武嗣, 井街宏, 梅津光生, 許俊鋭, 佐瀬一洋, 高谷節雄, 松田暉

人工臓器 36 ( 1 ) 6 - 12 2007.06
「NEDO」企業化資金の取り方

梅津光生

人工臓器 36 ( 1 ) 32 2007.06
機械工学技術は非臨床試験にどのように貢献できるか

梅津光生

第7回医療機器臨床試験研究会、第7回医療機器臨床試験研究会資料東京CRO株式会社 19 - 23 2007.05
機械式小児循環シミュレーションに基づく肺動脈弁設計開発の試み

末永健, 馮忠剛, 中村孝夫, 白石泰之, 山家智之, 西條芳文, 関根一光, 宮崎隆子, 山岸正明, 岡本吉弘, 田中隆, 梅津光生

第46回日本生体医工学学会大会、生体医工学第45巻特別号(第46回日本生体医工学学会大会プログラム・抄録集) 123 2007.04
人工心筋収縮構造制御による補助効率最適化に関する基礎検討

白石泰之, 山家智之, 関根一光, 西條芳文, 金野敏, 仁田新一, 和田由美子, 坂田亮, 梅津光生, 小川大祐, 佐藤文博, 角張泰之, 田中明, 吉澤誠, 本間大

、第46回日本生体医工学学会大会、生体医工学第45巻特別号(第46回日本生体医工学学会大会プログラム・抄録集) 183 2007.04
人工臓器の安全・安心をどう獲得するか?

梅津光生

第46回日本生体医工学学会大会、シンポジウム、生体医工学第45巻特別号(第46回日本生体医工学学会大会プログラム・抄録集) 2007.04
胸腹部大動脈瘤手術のための大動脈瘤ナビゲーションシステムの開発

青見茂之, 齋藤聡, 冨岡秀行, 黒澤博身, 伊関洋, 中村亮一, 村垣善浩, 西井規子, 植松美幸, 梅津光生

日本画家学会定期学術集会、SY-2-9 2007.04
独自の組織無細胞化技術による体内で再生・自己化を促す心臓弁及び血管の創生

岩﨑清隆, 尾崎重之, 山口晋平, 佐竹祥明, 安田稔, 大関泰宏, 梅津光生

第35回人工心臓と補助循環懇話会抄録集 37 2007.03
心臓外科領域における医工連携

梅津光生

第20回胸部心臓血管外科セミナー 2007.03
胸部大動脈置換術用ナビゲーションシステムの臨床応用

植松美幸, 青見茂之, 鈴川浩一, 西井規子, 中村亮一, 村垣善浩, 伊関洋, 上杉繁, 梅津光生

日本コンピューター外科学会誌 8 ( 4 ) 417 - 424 2007.03
胸腹部大動脈置換用名ナビゲーションシステムの臨床応用

植松美幸, 青見茂之, 鈴川浩一, 西井規子, 中村亮一, 村垣善浩, 伊関洋, 上杉繁, 梅津光生

日本コンピュータ外科学会誌 8 ( 4 ) 417 - 424 2007.03
1施設1台:戸山の常備薬型補助人工心臓の実用化

梅津光生

、平成18年度厚生労働科学研究費研究成果等普及啓発事業身体機能解析・補助・代替機器開発研究研究成果発表会、研究成果発表会要旨集 1 2007.02
再生医療を支える最先端技術への展望

梅津光生, 岩﨑清隆

、第5回薬時エキスパート研修会—再生医療研究再前腺-、要旨集 8 - 11 2007.02
再生医療を支える最先端技術と将来への展望、

梅津光生, 岩﨑清隆

第5回薬事エキスパート研修会—再生医療研究最前線— 日本公定書協会 8 - 11 2007.02
1施設1台:富山の常備薬型補助人工心臓の実用化

梅津光生他

第18年度厚生労働科学研究費研究成果等普及啓発事業身体機能解析・補助・代替機器開発研究研究成果発表会要旨集 1 - 2 2007.02
Arch graft のCFD血流性能評価

銭逸, 福井勇, 梅津光生

第19回バイオエンジニアリング講演会講演論文集 52 - 53 2007.01
リアルタイム周波数解析を用いた人工弁閉鎖期に発達する瞬時高周波ストレスの検討

石川大輔, 八木高伸, 須藤宏幸, 若狭翔太朗, 阿久津敏乃介, 岩﨑清隆, 梅津光生

第19回バイオエンジニアリング講演会講演論文集 60 - 61 2007.01
ステレオPIV法をもちいた大動脈バルサルバ洞内での3次元流れ場構造の基礎検討

須藤宏幸, 八木高伸, 石川大輔, 若狭翔太朗, William Yang, 岩﨑清隆, 梅津光生

第19回バイオエンジニアリング講演会講演論文集 62 - 63 2007.01
末梢Stent耐久性評価を目的トシタねじり型加速疲労試験装置の開発

錦織晃, 岩﨑清隆, 坪内俊介, 梅津光生

第19回バイオエンジニアリング講演会講演論文集 80 - 81 2007.01
Coil compaction予測のための時系列PIV法を用いた実形状弾性脳動脈モデル内の流れの可視化

松本徹, 岩﨑清隆, 八木高伸, 福島桃子, 鴨田憲明, 高尾洋之, 石橋敏寛, 村山雄一, 阿久津敏乃介, 梅津光生

第19回バイオエンジニアリング講演会講演論文集 82 - 83 2007.01
脳血管系疾患のCFDによる解析:PIV可視化実験とValidation

原田哲司, 福井弘一, 銭逸, 岩﨑清隆, 梅津光生, 高尾洋之, 石橋敏寛, 村山雄一

第19回バイオエンジニアリング講演会講演論文集 88 - 89 2007.01
生体心臓の構造を考慮した人工心筋開発の試み

白石泰之, 関根一光, 西條芳文, 山家智之, 伊藤慎二, 増本憲泰, 本間大, 藤本哲, 梅津光生, 仁田新一

第19回バイオエンジニアリング講演会 238 - 239 2007.01
胸腹部大動脈置換術の新しいナビゲーションシステムの開発と臨床応用(大動脈ナビゲーション)

青見茂之, 植松美幸, 伊関洋, 斉藤聡, 冨岡秀行, 西井規子, 飯村浩, 中村亮一, 村垣善浩, 鈴川浩一, 安藤隼人, 原美紀子, 黒澤博身, 梅津光生

適応医学 10 ( 2 ) 9 - 13 2007.01
心臓血管系に整合する人工血管開発のための医工学的評価手法

白石泰之, 岩村弘志, 藤本哲男, 梅津光生, 川副浩平

適応医学 10 ( 2 ) 14 - 23 2007.01
僧帽弁形成術の進歩と医工学の貢献

加瀬川均, 梅津光生

適応医学 10 ( 2 ) 24 - 31 2007.01
僧帽弁形成術に対する医工学の役割

有田誠, 野田怜子, 平山智博, 加瀬川均, 梅津光生

適応医学 10 ( 2 ) 32 - 39 2007.01
Hemodynamic analysis of cerebral aneurysm and stenosed carotid bifurcation using computational fluid dynamics technique

Yi Qian, Tetsuji Harada, Koichi Fukui, Mitsuo Urnezu, Hiroyuki Takao, Yuichi Murayama

Life System Modeling and Simulation, Proceedings 4689 292 - 299 2007 [Refereed]

　View Summary

Cerebrovascular diseases are one of the three major mortalities in Japan, such as the rupture of cerebral aneurysm and cerebral infarction caused by carotid stenosis. The growth mechanism of the cerebral aneurysm and carotid stenosis has not been clearly understood. In this research, we are introducing a numerical simulation tool; Computational Fluid Dynamics (CFD) technique, to simulate and predict the hemodynamics of blood passing through the cerebral aneurysms and stenosed carotid arteries. The results of a ruptured and an unruptured cerebral aneurysm were compared. Energy losses were calculated in ruptured and unruptured cerebral aneurysms, the results were 167 Pa and 6.3 Pa respectively. The results also indicated that the blood flows took longer residence inside of bleb of the ruptured aneurysm. The maximum wall shear stress was observed at 70% stenosis from the simulation results of stenosed carotid bifurcation. The result qualitatively agrees with classical treatments in carotid bifurcation therapy.
Investigation of a hydrodynamic performance of a ventricular assist device after its long-term use in clinical application

Yuma Kokuzawa, Tomohiro Shima, Masateru Furusato, Kazuhiko Ito, Takashi Tanaka, Toshibiro Igarashi, Tomohiro Nishinaka, Kiyotaka Iwasaki, Mitsuo Umezu

Life System Modeling and Simulation, Proceedings 4689 429 - 435 2007 [Refereed]

　View Summary

A long-term durability of a ventricular assist device (VAD) is required due to a shortage of donor hearts for cardiac transplantation, but there is no analyzed pump data after long-term use. This study aimed to perform a comparative study between new VAD and VADs after long-term use. The hydrodynamic performance of the used Toyobo VADs (mean period of 5 months with the maximum of 12 months) was evaluated in a mock circulatory system, where a new VAD was used as a control. Although a remarkable difference was not observed in terms of mean flow rate, flow and pressure waveforms varied significantly. Then, the pressure-volume relationship of each pump was measured: It was found that the capacity of long-term VADs was reduced. Although a further study is required, these results suggested that a long-term use of VAD may cause a change in mechanical properties of polymer materials.
故・土屋喜一教授を偲ぶ会:皆弦機会(みなげんきか〜い)の報告

梅津光生

第17回バイオフロンティア講演会講演論文集 1 - 2 2006.11
形状記憶合金を応用した心室収縮補助装置の心臓に適合した設計

和田由美子, 白石泰之, 伊藤慎二, 坂田亮, 植松美幸, 田中隆, 朴栄光, 梅津光生, 関根一光, 金野敏, 西條芳文, 山家智之, 仁田新一, 田中明, 吉澤誠, 増本憲泰, 藤本哲男, 本間大

第17回バイオフロンティア講演会講演論文集 43 - 44 2006.11
Navigation system for vascular surgery :Clinical experience for thoracoabdominal aortic replacement

Mitsuo Umezu, Miyuki Uematsu, Shigeru Uesugi, Ryoichi Nakamura, Hiroshi Iseki

Shanghai Jiao-tong University-Waseda University Medical Engineering Symposium 4 2006.10
Effective driving method of the vacuum-formed spiral vortex pump

Mitsuo Umezu, Takashi Tanaka, Kiyoyaka Iwasaki, Tomohiro Shima

Shanghai Jiao-tong University-Waseda University Medical Engineering Symposium 5 2006.10
A preliminary research in cerebral aneurysms risk factors analysis using computational fluid dynamics

Yi Qian, Tetsuji Harada, Mitsuo Umezu, Hiroyuki Takao

Shanghai Jiao-tong University-Waseda University Medical Engineering Symposium 11 2006.10
Development of a self-training system for coronary bypass surgery designed by mechanical enginners

Mitsuo Umezu

88thICB Seminar,Circulatory and respiratory processes-modelling, mechanical assistance and applications in anaesthesia, Intensive care and biofeedback Polska academia nauk MCB 2006.10
もうひとつのEBM:Enginering Based Med

梅津光生

第44回日本人工臓器学会大会予稿集、人工臓器 35 ( 2 ) 2006.10
次世代型人工心臓システム評価ガイドライン:審査ガイドライン策定ワーキンググループによる検討

巽英介, 松田暉, 井街宏, 梅津光生, 許俊鋭, 佐瀬一洋, 高谷節雄, 中谷武嗣

第44回日本人工臓器学会大会予稿集、人工臓器 35 ( 2 ) s-21 2006.10
低侵襲手術を定量評価するための医工学的アプローチ

梅津光生, 朴栄光, 白石泰之, 有田誠, 岩﨑清隆, 田中隆, 青見茂之, 加瀬川均, 竹村博文, 夜久均, 川副浩平

第44回日本人工臓器学会大会予稿集、人工臓器 35 ( 2 ) s-57 2006.10
微細機能繊維を応用した機会式人工心筋の開発-心室補助効果と血管負荷整合

白石泰之, 山家智之, 西條芳文, 関根一光, 小川大祐, 佐藤文博, 角張泰之, 伊藤慎二, 坂田亮, 和田由美子, 田中隆, 梅津光生, 田林晄一, 比嘉昌, 田中明, 吉澤誠, 藤本哲男, 増本憲泰, 仁田新一

第44回日本人工臓器学会大会予稿集、人工臓器 35 ( 2 ) s - 98 2006.10
The mRNA expression of adhesion molecules in cardiomyocytes under in vivo and in vitro conditions

馮忠剛, 大槻晶子, 野村保友, 北嶋龍雄, 中村孝夫, 梅津光生

第44回日本人工臓器学会大会予稿集、人工臓器 35 ( 2 ) s - 121 2006.10
マイクロ波と拍動循環を駆使した無細胞化技術による再生促進型大動脈弁

岩﨑清隆, 尾崎重之, 川井貴裕, 山口晋平, 江藤元治, 大庭幸裕, 大関泰宏, 島ノ内正起, 梅津光生

第44回日本人工臓器学会大会予稿集、人工臓器 35 ( 2 ) s - 122 2006.10
循環シミュレータにおける超音波診断装置を用いた僧帽弁形成術の評価

平山智博, 有田誠, 加瀬川均, 高山大祐, 小松崎ひとみ, 岩﨑清隆, 梅津光生

第44回日本人工臓器学会大会予稿集、人工臓器 35 ( 2 ) s - 135 2006.10
形状記憶合金を応用した人工心筋要素の機械特性と駆動制御に関する基礎検討、

伊藤慎二, 白石泰之, 和田由美子, 坂田亮, 植松美幸, 田中隆, 小川大祐, 関根一光, 吉澤誠, 田中明, 西條芳文, 山家智之, 岡本英治, 本間大, 藤本哲男, 梅津光生

第44回日本人工臓器学会大会予稿集、人工臓器 35 ( 2 ) s - 167 2006.10
胸腹部大動脈置換術用ナビゲーションシステムの臨床応用

植松美幸, 青見茂之, 鈴川浩一, 安藤隼人, 原美紀子, 西井規子, 飯村浩, 中村亮一, 村垣善浩, 伊関洋, 上杉繁, 梅津光生

第15回日本コンピュータ外科学会大会・第16回コンピュータ支援画像診断学会大会合同論文集 171 - 172 2006.10
Experimental assessment of the drainage capacity of small silastic chest drains

Hiroshi Niinami, Mimiko Tabata, Yasuko Takeuchi, Mitsuo Umezu

Asian cardiovascular and thoracic annals 14 ( 3 ) 2006.10
血液循環系の模擬循環システム

梅津光生

フルードパワーシステム 37 ( 5 ) 56 - 59 2006.09
拍動環境下と静的環境下における抗血栓性材料のin vitro血液適合性の比較検討

中安妙子, 岩﨑清隆, 竹内有理, 江口正芳, 石原一彦, 梅津光生

第22回ライフサポート学会大会、第4回生活支援工学系学会連合大会抄録 37 2006.09
量産向け旋回渦流型拍動補助人工心臓用駆動方法の検討

田中隆, 岩﨑清隆, 島智宏, 古里正光, 伊藤一彦, 梅津光生

第22回ライフサポート学会大会、第4回生活支援工学系学会連合大会抄録 149 2006.09
Real- Time planar spectral analysis of instantaneous high-frequency stress on blood cells downstream of an artificial heart valve

T Yagi, D Ishikawa, H Sudo, T Akutsu, W Yang, K Iwasaki, M Umezu

12th International Symposium on Flow Visualization 65 ( 3 ) 239 2006.09
Preliminary study on the cardiac functional reproduction by mechanical elements

S Itoh, Y Shiraishi, Y Wada, R Sakata, M Uematsu, Y Park, T, Tanaka, K Sekine, Y saijo,T Yambe, D Homma,M Umezu

International joint conference of INABIO/SMEBA 2006 Abstract book 98 2006.09
WETLAB からDRYLABへ‐冠動脈吻合訓練装置と僧帽弁シミュレータ‐

梅津光生

MEDICAL TORCH 外科医のための現場と症例 2006 no.4 28 - 29 2006.09
血管循環シミュレータ

梅津光生

新形態融合大学院への期待、未来医学シンポジウム2006抄録集 2 2006.06
胸腹部大動脈瘤手術のための大動脈流ナビゲーションの開発

青見茂之, 伊関洋, 梅津光生

第10回適応医学学会、適応医学 ( 10 ) 18 2006.06
バイオエンジニアリングによる人工血管性能評価および手術支援

白石泰之, 梅津光生

第10回適応医学学会、適応医学 ( 10 ) 18 2006.06
僧帽弁形成術に対する医工学の役割

有田誠, 野田玲子, 平山智博, 加瀬川均, 梅津光生

第10回適応医学学会、適応医学 ( 10 ) 19 2006.06
脳動脈流の医学的問題点とバイオエンジニアリングを用いた研究の期待

高尾洋之, 村山雄一, 石橋敏寛, 八木高伸, 岩﨑清隆, 銭逸, 梅津光生

第10回適応医学学会、適応医学 ( 10 ) 21 2006.06
末梢ステントの加速耐久試験装置の開発〜短期間で長期の有用性を予測する技術〜

岩﨑清隆, 長谷川厚, 錦織晃, 森田祐樹, 梅津光生

第10回適応医学学会、適応医学 ( 10 ) 21 2006.06
Multiplane scanning Stereo-PIV measurements of flow inside a spiral vortex pulsatile blood pump

Takanobu Yagi, William Yang, Daisuke Ishikawa, Hiroyuki Sudo, Kiyotaka Iwasaki, Mitsuo Umezu

13th international symposium applications of laser thchniques to fluid mechanics 11.5 2006.06
冠状動脈バイパス手術における吻合手技訓練用血管モデルの開発

三田裕, 朴栄光, 沖恵理子, 岩田浩康, 白石泰之, 高西淳夫, 竹村博文, 梅津光生

ROBOMEC2006 豊かな生活に向けたRTの集大成・ロボティクス・メカトロニクス講演会2006講演概要集 5 2006.05
手術室における医療機器・スタッフの最適配置の検討

安藤隼人, 植松美幸, 森田篤, 上杉繁, 中村亮一, 伊関洋, 西澤幸司, 梅津光生

ROBOMEC2006 豊かな生活に向けたRTの集大成・ロボティクス・メカトロニクス講演会2006講演概要集 86 2006.05
胸腹部領域における手術ナビゲーションシステムの開発大動脈瘤を対象として

植松美幸, 鈴川浩一, 上杉繁, 安藤隼人, 森田篤, 青見茂之, 西井規子, 飯村浩, 中村亮一, 伊関洋, 梅津光生

ROBOMEC2006 豊かな生活に向けたRTの集大成、ロボティクス・メカトロニクス講演会2006講演概要集 81 2006.05
若い心臓外科医へのメッセージ

梅津光生

第36回日本心臓血管外科学会学術総会、日本心臓血管外科学会雑誌、 34 2006.04
人工心臓装着訓練装置開発のための基礎検討

梅津光生, 朴栄光, 三田裕, 沖恵理子, 植松美幸, 田中隆, 岩﨑清隆, 高西淳夫, 白石泰之, 青見茂之, 竹村博文, 夜久均, 川副浩平

第34回人工心臓と補助循環懇話会プログラム・抄録集 44 2006.03
富山の常備薬型人工心臓の実用化は可能か?

梅津光生, 須藤知浩, 島智宏, 古里正光, 山本雅也, 田中隆, 伊藤一彦, 岩﨑清隆, 井街宏, 石原一彦

第34回人工心臓と補助循環懇話会プログラム・抄録集 51 2006.03
形状記憶合金を応用した心筋収縮補助装置の開発

梅津光生, 永利潤, 伊藤慎二, 白石泰之, 田中隆, 本間大, 藤本哲男

平成14年度文部科学省学術フロンティア推進事業採択平成17年度生体医工学研究センター公開研究成果報告会講演要旨集 47 - 50 2006.03
Development of “Patient Robot”;training robot based on quantitative analysis of surgical technique

Youg-Kwang Park, Yutaka Mita, Eriko Oki, Hiroyasu Iwata, Yasuyuki Shiraishi, Atsuo Takanishi, Hirofumi Takemura, Mitsuo Umezu

BioRob 2006, Biomedical Robotics and Biomechatronics 148 2006.02 [Refereed]
Development of of “Patient Robot”;measurement system of myocardial behaviors for the quantitative evaluation of the surgical robot technology

Miyuki Uematsu, Hayato Ando, Atsushi Morita, Sigeru Uesugi, Kiyoyaka Iwasaki, Mitsuo Umezu, Yasuyuki Shiraishi

BioRob 2006, Biomedical Robotics and Biomechatronics 150 2006.02 [Refereed]
Biomedical engineering analysis of effectiveness of cardiovascular surgery:Anastomosis methods for coronary artery bypass grafting

M.Umezu, J.Kawai, J.Suehiro, M.Arita, Y.Shiraishi, K.Iwasaki, T.Tanaka, T.Akutsu, H.Niinami

Biocybernetics and biomedical engineering 2006 26 ( 1 ) 61 - 67 2006.02
Another EBM: Engineering based medicine for the quantitative evaluation of medical devices or surgical treatment,Internatuinal Workshop HITS 2006,Frontiers of Biomeasurement and Nanobiotechnology toward Biomedical Engineering

梅津光生

静岡ガンセンター 46 2006.01
Innovative bioreactor technologies produced a completely decellularized and pre-endothelialized functional aortic heart valve

K Iwasaki, S Ozaki,T Kawai, S Yamaguchi, M Eto, Y Ohba, Y Ohzeki,M Umezu

The 12th international conference on biomedical engineering,IFMBE proceedings 12 1A2 - 07 2005.12
Effect of mechanical assistance on cardiac function by using shape memory alloy fibered artificial myocardium

Y Shiraishi, J Nagatoshi, S Itoh,T Yambe, K Sekine,Y Saijo, Q, Wang,H Liu, S Nitta, S Konno, D Ogawa, Olegario, M Yoshizawa, A Tanaka, F Sato, Y Park, M, Uematsu, m Higa, Y Hori, T Fujimoto, K Tabayashi, H Sasada, N Masumoto, M Umezu, D Homma

The 12th international conference on biomedical engineering,IFMBE proceedings 12 1A3 - 01 2005.12
Influence of drive conditions on hemodynamic performance of undulation type artificial heart

D Sone, Y Yada, K, Ishikawa, I Saito, M Umezu, Y Abe, K Imachi

The 12th international conference on biomedical engineering,IFMBE proceedings 12 1A3 - 04 2005.12
Development of an inexpensive first-aid type ventricular assit device driven by IABP consoles

T Sudo, K Iwasaki, Y Ohnishi, T Shima, T Tanaka, K Ito, M Umezu

The 12th international conference on biomedical engineering,IFMBE proceedings 12 1A3 - 05 2005.12
An experimental investigation of three-dimensional pulsatile flow structures within the spiral vortex ventricular assist device using stereoscopic piv

T Yagi, W Yang, D Ishikawa, h Sudo, K Iwasaki, M Umezu

The 12th international conference on biomedical engineering,IFMBE proceedings 12 1A5 - 04 2005.12
Regional myocardial behaviour cardiac surface under arrhythmic conditions

M Uematsu, Y Shiraishi, K Sekine,T Yambe, Y Saijo, H Ando,Y Park, S Takeda, K Iwasaki, M Umezu

The 12th international conference on biomedical engineering,IFMBE proceedings 12 1A5 - 05 2005.12
Development of “Patient Robot”;surgical training machine for off-pump coronary artery bypass grafting

Y Park, K Nishikawa, Y Mita,E Oki, M Uematsu, Y Shiraishi, H, Takemura,H Yaku, K Kawazoe, A Takanishi, M Umezu

The 12th international conference on biomedical engineering,IFMBE proceedings 12 1A5 - 06 2005.12
An investigation of instantaneous high-frequency turbulent stress in the vicinity of artificial heart valves using wavelet transform analysis pf dynamic piv measurements

T Yagi, D Ishikawa, H Sudo, T Akutsu, W Yang, K Iwasaki, M Umezu

The 12th international conference on biomedical engineering,IFMBE proceedings 12 1B2 - 06 2005.12
An experimental investigation of three-dimensional pulsatile flow structures within the spiral vortex ventricular assist device using stereoscopic piv

T Yagi, W Yang, D Ishikawa, h Sudo, K Iwasaki, M Umezu

The 12th international conference on biomedical engineering,IFMBE proceedings 12 , 1A3 - 06 2005.12
量産向け旋回渦流型人工心臓用金型(真空ポート)の検討

田中隆, 岩﨑清隆, 竹内有理, 伊藤一彦, 梅津光生

第3回生活支援工学系学会連合大会,講演予稿集 177 2005.12
左心室形成術における切除線決定のための診断法に関する基礎的検討

植松美幸, 白石泰之, 関根一光, 山家智之, 西條芳文, 安藤隼人, 朴栄光, 武田朴, 岩﨑清隆, 梅津光生

生体医工学 43 ( 4 ) 653 - 660 2005.12
国産初体内埋め込み型人工心臓の開発-意義ある医工連携の考え方-

梅津光生

日本ロボット学会、ロボット工学セミナー(第33回シンポジウム)未来医療を切り拓くRT〜基礎から臨床最前線〜 46 - 55 2005.12
Japanese implantable centrifugal left ventricular assist system: innovative design, performance and clinical application,Keynote 1.3 ,

Mitsuo Umezu

The 12th international conference on biomedical engineering, Programme and Abstracts 62 2005.12
形状記憶合金を応用した新しい心室収縮補助装置の開発

永利潤, 伊藤慎二, 植松美幸, 田中隆, 梅津光生, 白石泰之, 関根一光, 金野敏, 西條芳文, 山家智之, 田中明, 吉澤誠, 増本憲泰, 藤本哲男, 本間大

第16回バイオフロンティア講演会講演論文集 77 - 78 2005.11
体内植込み型人工心臓EVAHEART

山崎健二, 木原信一郎, 斎藤聡, 梅津光生, 太田英介, 富岡淳, 山崎俊一, 黒澤博身

第43回日本人工臓器学会大会予稿集 34 ( 2 ) 90 2005.11
Spiral Vortex型人工心臓内の拍動流の3次元構造を実験計測するステレオPIV法の開発

八木高伸, William Yang, 石川大輔, 須藤宏幸, 岩﨑清隆, 梅津光生

第43回日本人工臓器学会大会予稿集 34 ( 2 ) 97 2005.11
埋込み型人工心筋装置による補助循環の際の血行動態に関する検討

王慶田, 山家智之, 白石泰之, 西條芳文, 梅津光生, 仁田新一

第43回日本人工臓器学会大会予稿集 34 ( 2 ) 122 2005.11
材料の抗血栓性の信頼性のあるin vitro評価方法の確立に向けて

江口正芳, 岩﨑清隆, 竹内有理, 石原一彦, 梅津光生

第43回日本人工臓器学会大会予稿集 34 ( 2 ) 143 2005.11
マイクロ波照射かつ拍動循環による処理は大動脈弁を強度維持したまま完全無細胞化しα1-3ガラクトース抗原も除去する

岩﨑清隆, 尾崎重之, 川井貴裕, 山口晋平, 江藤元治, 大庭幸弘, 大関泰宏, 梅津光生

第43回日本人工臓器学会大会予稿集 34 ( 2 ) 151 2005.11
一次遅れ系ユニットを付与したIABP駆動装置による旋廻渦流型拍動ポンプの性能試験

島智宏, 岩﨑清隆, 大西悠介, 須藤知浩, 田中隆, 伊藤一彦, 梅津光生

第43回日本人工臓器学会大会予稿集 34 ( 2 ) 164 2005.11
循環シミュレータによる人工弁輪の医工学的評価

有田誠, 加瀬川均, 土井博文, 野田怜子, 平山智博, 梅津光生

第43回日本人工臓器学会大会予稿集 34 ( 2 ) 175 2005.11
人工弁近傍で発達する乱流に関する新評価手法の提言:時系列PIVとWavelet解析を用いた瞬時ストレスの周波解析

八木高伸, 石川大輔, 須藤宏幸, 阿久津敏乃介, William Yang, 岩﨑清隆, 梅津光生

第43回日本人工臓器学会大会予稿集 34 ( 2 ) 176 2005.11
医療用具の拍動下でのin vitro抗血栓評価システムの開発

竹内有理, 岩﨑清隆, 江口正芳, 中安妙子, 石原一彦, 梅津光生

第27回日本バイオマテリアル学会大会予稿集 150 2005.11
川井貴裕,岩﨑清隆,尾崎重之,山口晋平,江藤元治,大庭幸裕,大関泰宏,島内正起,梅津光生

マイクロ波及び拍動循環によるブタ組織の脱細胞化

第27回日本バイオマテリアル学会大会予稿集 226 2005.11
Development of an inexpensive vacuum formed ventricular assist device;spiral vortex pump

M Umezu, Y Onishi, T Sudo, shima,K Iwasaki, T, Tanaka、K Itoh

ESAO2005 33 2005.10
Development of a newly-designed artificial myocardial assist device using biometal

Y Shiraishi, T Yambe, K Sekine, N Masumoto, J, Nagatoshi, S Itoh, E, Okamoto,Y Saijo, Q, Wand, H Liu, S Nitta, S Konnno, D Ogawa, Olegario, M Yoshizawa, M Higa, A Tanaka, H Miura, F Sato, M, Uematsu, T Tanaka, T park, T Fujimoto, K Tabayashi, H Sasada, M Umezu, D Hommma

ESAO2005 34 2005.10
Numerical analysis for designing a new aortic cannula

T Fujimoto, M Aruga, S Nakano, N Kabei, M, Yoshida,M Umezu

ESAO2005 75 2005.10
Japanese made implantable centrifugal type ventricular assist system(LVAS):EVAHEART

Mitsuo Umezu

8th Japanese-Polish seminar on new engineering methods supporting human life 44 2005.09
Basic flow characteristics of a pulsatile blood pump driven by two different drivers

K Ito,T Sudo, T Shima, Y Kouno, Y Ohnishi, T Tanak, K Iwasaki, T, Fujimoto M Umezu

8th Japanese-Polish seminar on new engineering methods supporting human life 51 2005.09
A newly designed myocardial assist device using a sophisticated shape memory alloy fibre

Yasuyuki Shiraishi, Tomoyuki Yambe, Kazumitsu Sekine, Daisuke Ogawa, Jun Nagatoshi, Shinji Itoh, Miyuki Uematsu, Yoshifumi Saijo, Masaru Higa, Yoshio Hori, Hongjian Liu, Qingtia Wang, Satoshi Konnno, Takashi Kuwayama, Paul legario, Akira Tanaka, Noriyasu Masumoto, Ryuta Ibuki, Shigenao Maruyama, Mitsuo Umezu ほか

8th Japanese-Polish seminar on new engineering methods supporting human life 54 2005.09
New concept of “Patient Robot” based on cardiovascular analysis

M Umezu

Italy-Japan 2005 Workshop,The man and the robot:Italian and Japanese approaches 2005.09
System integration of totally implantable ventricular assist device,13th Congress of The International Society for Rotary Blood Pumps

Y Abe, T Chinzei, T Isoyama, T Ono, Y Nishitani, I Nemoto, Y Inoue, N Watanabe, H Asao, H Miura, Y Kakubari, S Arai, K Iwasaki, T Makino, E Okamoto, F Sato, S Mochizuki, A Kouno, H Funamizu, H Nakagawa, M Mitsui, N Taniguchi, N Mitsumune, A Sugino, M Ono, K Takiura, Y Mitamura, H Matsuki, M Umezu

Tokyo Medical and Dental University Dept of Artificial Organs 120 2005.09
Advancement of an implantable ventricular assist system using undulation pump under multi-institutional cooperative project

K Imachi, Y Abe, Y Mitamura, T Yambe, T Matsuda, E Okamoto, M Umezu, I Nemoto, A Mimaki,I Saito

Artificial Organs, 2004 ESAO-IFAO joint congress Sergio Stefoni, Congress President 29 ( 9 ) 726 2005.09
Microwave treatment combined with pulsatile circulation can completely remove cells and α1-3 galactose antigen

K Iwasaki, S Ozaki,T Kawai, Y Moriyama, Y Ohzeki,M Umezu

Artificial Organs, 2004 ESAO-IFAO joint congress Sergio Stefoni, Congress President 29 ( 9 ) 733 2005.09
In vitro anti-thrombogenic screening of biomaterials under practical pulsatile circulation

K Iwasaki, Y Takeuchi,M Eguchi, K Ishihara,M Umezu

Artificial Organs, 2004 ESAO-IFAO joint congress Sergio Stefoni, Congress President 29 ( 9 ) 740 2005.09
流体の流れ・血液の流れ

梅津光生

第6回日本急性血液浄化学会学術集会,抄録集 32 - 33 2005.09
Development of Japanese-made innovative implantable ventricular assist device(EVAHART):design concept, fine fabrication technologies, and experience of the first clinical application

Mitsuo Umezu, Kenji Yamazaki

The 2nd COE-CIR joint workshop on future technologies of mechatronics for its growing role in symbiotic society with human, Center for intelligent robotics Korea and Center of excellence,Waseda University Japan 19 - 21 2005.08
Biomedical engineering analysis on the effectiveness of cardiovascular surgery:Anastomosis methods for coronary artery bypass grafting

M Umezu, J Kawai, J Suehiro, M Arita,Y Shiraishi, K Iwasaki, T, Tanak,T Akutsu, H Niinami

Lecture notes of the ICB seminar 7th Polish-Japanese seminar on new technologies for future artificial organs,Miedzynarodowe Centrum Biocybernetyki 80 - 88 2005.08
Stereoscopic particle image velocimetry measurements toward three dimensional flow investigations within the spiral vortex blood pump

T Yagi, W Yang, D Ishikawa, K Iwasaki, M Umezu

Lecture notes of the ICB seminar 7th Polish-Japanese seminar on new technologies for future artificial organs,Miedzynarodowe Centrum Biocybernetyki 106 - 112 2005.08
Development of an artificial myocardial assist system

Y Shiraishi, T Yambe, E Okamoto,Y Saijo, K Sekine, Y Hori, T kuwayama, S Nitta, F Sato, D Ogawa, Olegario,A Tanaka, M Yoshizawa, Q Wang, X Duan,H Liu, H Aoki, J, Nagatoshi, S Ito, M Umezu, T Fujimoto, N Masumoto, K, Tabayashi, H Sasada

Lecture notes of the ICB seminar 7th Polish-Japanese seminar on new technologies for future artificial organs,Miedzynarodowe Centrum Biocybernetyki 119 - 125 2005.08
The use of patterned dual thermoresponsive surfaces for the collective recovery as co-cultured cell sheets

Y Tsuda, A Kikuchi, M Yamato, A Nakao, Y Sakurai, M Umezu, T Okano

BIOMATERIALS 26 ( 14 ) 1885 - 1893 2005.05 [Refereed]

　View Summary

Heterotypic cell interactions are critical to achieve and maintain specific functions in many tissues and organs. We have focused on patterned structure surfaces to enable co-culture of heterotypic cells and recovery of patterned co-cultured cell sheets for applications in tissue engineering. Thermoresponsive polymers exhibiting different transition temperatures in water comprise both poly(N-isopropylacrylamide) (PIPAAm) and n-butyl methacrylate (BMA) co-grafted as side chains to PIPAAm main chains. The se copolymers were surface-grafted in patterns to obtain patterned dual thermoresponsive Cell culture surfaces using electron beam polymerisation method and porous metal masks. On patterned surfaces. site-selective adhesion on and growth of rat primary hepatocytes (HCs) and bovine carotid endothelial cells (ECs) allowed patterned co-culture, exploiting hydrophobic/hydrophilic surface chemistry regulated by culture temperature as the sole variable. At 27degreesC. seeded HCs adhered exclusively onto hydrophobic, dehydrated P(IPAAm-BMA) co-grafted domains (1-mm diamater area), but not onto neighbouring hydrated PIPAAm domains. Sequentially seeded ECs then adhered exclusively to hydrophobised PIPAAm domains upon increasing culture temperature to 37degreesC, achieving patterned co-cultures. Reducing culture temperature to 20degreesC promoted hydration of both polymer-grafted domains, permitting release of the co-cultured, patterned cell monolayers as continuous cell sheets with heterotypic cell interactions. Recovered co-cultured cell sheets can be manipulated, moved and sandwiched with other structures. providing new useful constructs both for basic cell biology research and preparation of tissue-mimicking multi-layer materials through overlaying co-cultured cell sheets. (C) 2004 Elsevier Ltd. All rights reserved.

DOI

Scopus

178

Citation

(Scopus)
体内埋め込み型心室収縮補助装置の開発

梅津光生, 青木秀宜, 永利潤, 伊藤慎二, 須藤知浩, 白石泰之, 田中隆, 藤本哲男

平成14年度文部科学省学術フロンティア推進事業採択・平成16年度生態医工学研究センター公開研究成果報告会「循環器系障害発生の解明および治癒に対する流体力学および分子生物学的研究」講演要旨集、芝浦工業大学先端工学研究機構生体医工学センター 11 - 14 2005.03
様々な負荷に対する心機能変化計測への試み,

植松美幸, 白石泰之, 関根一光, 山家智之, 西條芳文, 武藤俊介, 朴栄光, 安藤隼人, 松本徹, 武田朴, 岩崎清隆, 梅津光生, 内山明彦

電気学会研究会資料,医用・生体工学研究会 MBE-05-1〜6 23 - 26 2005.02
量産向け旋廻渦流型人工心臓用金型(真空ポート)の検討

田中隆, 岩﨑清隆, 竹内有理, 伊藤一彦, 梅津光生

ライフサポート 17 ( 3 ) 2005
完全埋め込み型心室収縮補助装置の開発

青木秀宜, 永利潤, 伊藤慎二, 須藤知浩, 梅津光生, 白石泰之, 関根一光, 西條芳文, 山家智之, 仁田新一, 岡本英治, 小川大祐, 吉澤誠, 田中明, 佐々田比呂志, 田林晄一, 本間大

日本機械学会,第17回バイオエンジニアリング講演会,講演論文集 191 - 192 2005.01
脳動脈瘤治療法の評価を目的とした拍動循環シミュレータの開発

栗山仁志, 岩崎清隆, 八木高伸, 高島俊洋, 藤井麻由, 石川大輔, 梅津光生, 阿久津敏乃介, 高尾洋之, 石橋敏寛, 村山雄一

日本機械学会,第17回バイオエンジニアリング講演会,講演論文集 397 - 398 2005.01
Present status of Japanese implantable centrifugsl type ventricular assit system(LVAS):Evaheart

Umezu M, YamazakiK, Yamazaki S, Kurasawa H, Iwasaki K

First Shanghai congress on heart assist and mechanical circulatory support 27 - 29 2004.12
反射球マーカを用いたOpenMRI下脳外科手術ナビゲーションシステムの臨床応用

武藤俊介, 安藤隼人, 長嶋義昭, 植松美幸, 鈴川浩一, 中村亮一, 伊関洋, 村垣善浩, 梅津光生

第13回日本コンピュータ外科学会大会・第14回コンピュータ支援画像診断学会大会,,早稲田大学 197 - 198 2004.12
人工弁

岩崎清隆, 梅津光生

人工臓器 33 ( 3 ) 178 - 186 2004.12
Biomedical engineering approach to evaluate anastomosis methods for coronary artery bypass grafting

M UMEZU, J KAWAI, J, SUEHIRO, M ARITA, Y SHIRAISHI, K IWASAKI, T TANAKA, H NIINAMI

Journal of Shanghai University 2004 10 25 - 28 2004.10
In vitro mitral simulator to evaluate effectiveness of valvoplasty technique

H DOI,M ARITA, M, OKUDA,R NODA, K IWASAKI, T TANAKA, H, KASEGAWA, M UMEZU

Journal of Shanghai University 2004 10 29 - 31 2004.10
In vitro hydrodynamic test and in vitro hemolysis test for development of inexpensive spiral vortex ventricular assisting system using IABP console

Y OHNISHI, K IWASAKI, H MIZUTA, T SUDO, S MUTO,T SHIMA, T TANAKA, K ITO, M UMEZU

Journal of Shanghai University 2004 10 32 - 36 2004.10
拍動型人工心臓材料のin vitro血液適合性評価方法の検討

竹内有理, 岩﨑清隆, 佐伯航, 石原一彦, 梅津光生

第20回ライフサポート学会大会講演予稿集,pp157-158 157 - 158 2004.09
低価格旋回渦流型拍動血液ポンプの製作法の検討

須藤知浩, 岩﨑清隆, 吉田敬, 田中隆, 伊藤一彦, 梅津光生

第20回ライフサポート学会大会講演予稿集 155 - 156 2004.09
Supporting effect of the implantable undulation pump ventricular assist device on ischemic heart failure

T Yambe, Y Shiraishi, Y Abe, K Imachi, I Saito, S Mochizuki, Y Mitamura, M Umezu, T matsuda, E, Okamoto,S Nitta

The international journal of artificial organs,European society for artificial organs 27 ( 7 ) 17 2004.09
Development of dynamic particle image velocimetry toward the study of Spatio-Temporal dynamics of turbulent flow in artificial heart valves

T Yagi, D Ishikawa, T Akutsu, K Iwasaki, Y noguchi, M Umezu

The international journal of artificial organs,European society for artificial organs 27 ( 7 ) 40 2004.09
A newly designed cannula for left ventricular bypass

T Fujimoto, A Yonekawa, M Aruga,N Kabei, M, Yoshida,M Umezu

The international journal of artificial organs,European society for artificial organs 27 ( 7 ) 112 2004.09
Invitro study of commercially available annuloplasty rings for mitral regurgitation

R Noda, M Arita, M Okuda, H Doi, K Iwasaki, T Tanaka, H, Kasegawa,M Umezu

The international journal of artificial organs,European society for artificial organs 27 ( 7 ) 129 2004.09
A completely decellularized and pre-cellularized tissue engineered aortic valve using innovative bioreactor technologies

Kiyotaka IWASAKI, Shigeyuki OZAKI, Takeshi NAKAZAWA, Takahiri KAWAI, Yuichi IMAI, Masayuki ISHIHARA, Yoshito MORIYAMA, Yasuhuro OZAKI, Yuji MORIMOTO, Makoto KIKUCHI, Mitsuo UMEZU

Advances in tissue engineering and biology of heart valves,Imperial college London Georgia institute of technology university of Florence 80 2004.09
Innovative decellularization and pre-endothelialization technologies to develop a tissue-engineered aortic valve

Iwasaki K, Ozaki S, Nakazawa T, Kawai T, Imai Y, Umezu,M

76th ICB seminar 7th Polish-Japanese Seminar,New technologies for future artificial organs 38 - 39 2004.09
Biomedical engineering analysis on the effectiveness of cardiovascular surgery:Anastomosis methods for coronary artery bypass grafting

Mitsuo UMEZU, Junko KAWAI, Junichi SUEHIRO, Makoto ARITA, Yasuyuki SHIRAISHI, Kiyotaka IWASAKI, Takashi TANAKA, Hiroshi NIINAMI

76th ICB seminar 7th Polish-Japanese Seminar,New technologies for future artificial organs 26 - 27 2004.09
The development of stereoscopic particle veiocimetry toward comprehensive study of three-dimensional pulsatile-flow phenomena within the Spiral Vortex blood pump

T Yagi, W Yang, D Ishikawa, K Iwasaki, M Umezu

76th ICB seminar 7th Polish-Japanese Seminar,New technologies for future artificial organs 31 - 32 2004.09
Development of an artificial myocardial assist system

Y Shiraishi, T yambe,E Okamoto, Saijo K Sekine, Y Hori,T Kuwayama, S Nitta, F Sato,D Ogawa, Olegario,a Tamaka, M Yoshizawa, Q Wang, X Duan,H Liu, H Aoki, Nagatoshi,S,Ito, U Umezu, K Tabayashi, h Sasada

76th ICB seminar 7th Polish-Japanese Seminar,New technologies for future artificial organs 36 2004.09
拍動型人工心臓内の流れ場の3次元構造および時系列現象を計測する新可視化技術の基礎検討

八木高伸, 石川大輔, Yang William, 阿久津敏之介, 岩﨑清隆, 野口康雄, 梅津光生

第42回日本人工臓器学会大会予稿集,人工臓器 33 ( 2 ) s-146 2004.09
拍動循環下でのマイクロ波照射による組織脱細胞化及び生理的は工藤環境での細胞播種技術に基づく動物実験用大動脈弁の開発

岩﨑清隆, 尾崎重之, 川井貴裕, 中澤剛, 今井裕一, 大関泰宏, 黒岩佐和子, 森山嘉人, 石原雅之, 守本裕司, 菊地眞, 梅津光生

第42回日本人工臓器学会大会予稿集、人工臓器 33 ( 2 ) s-135 2004.09
急性心不全患者の心機能改善を目的とした超低価格拍動型の旋回渦流型補助人工心臓の開発戦略と性能試験

岩﨑清隆, 梅津光生, 吉田敬, 須藤知浩, 大西悠介, 田中隆

第42回日本人工臓器学会大会予稿集、人工臓器 33 ( 2 ) s-147 2004.09
生理的拍動環境を創出可能な血液適合性評価装置による医療用具及び医用材料のin vitro抗血栓性スクリーニング試験

岩﨑清隆, 竹内有理, 佐伯航, 石原一彦, 梅津光生

第42回日本人工臓器学会大会予稿集、人工臓器 33 ( 2 ) s-150 2004.09
僧帽弁手術をサポートする血液循環シミュレータの開発

梅津光生, 土井博文, 野田玲子, 岩﨑清隆, 有田誠, 加瀬川均

第42回日本人工臓器学会大会予稿集、人工臓器 33 ( 2 ) s-160 2004.09
血液循環シミュレーションモデルによる透析シャント用ePTFE人工血管の拍動抵抗特性の検討

白石泰之, 関根一光, 山家智之, 西條芳文, 青木秀宜, 梅津光生, 藤本哲男, 内野敬

第42回日本人工臓器学会大会予稿集、人工臓器 33 ( 2 ) s-172 2004.09
遠心型日補助人工心臓EVAHEARTの溶血に対する安全性評価

宮越貴之, 岩﨑清隆, 大西悠介, 水田英伸, 梅津光生, 山崎健二, 北野智哉, 藤井哲也, 牛山博之, 得能敏正, 山崎俊一

第42回日本人工臓器学会大会予稿集、人工臓器 33 ( 2 ) s-188 2004.09
完全埋込みを目指した人工心室補助装置の血行力学的影響-慢性動物実験における心収縮補助効果の検討-

白石泰之, 山家智之, 岡本英治, 関根一光, 小川大祐, オレガリオポール, 吉澤誠, 青木秀宜, 永利潤, 伊藤慎二, 田中明, 佐藤文博, 西條芳文, 王慶田, 圓山重直, 早瀬敏幸, 松木英敏, 本間大, 梅津光生, 仁田新一

第42回日本人工臓器学会大会予稿集,人工臓器 33 ( 2 ) S-193 2004.09
低価格旋廻渦流型拍動血液ポンプの製作法の検討

須藤知浩, 岩﨑清隆, 吉田敬, 田中隆, 伊藤一彦, 梅津光生

第2回生活支援工学系学会連合大会講演予稿集 155 - 156 2004.09
拍動型人工心臓材料のin vitro血液適応性評価方法の検討

竹内有理, 岩﨑清隆, 佐伯航, 石原一彦, 梅津光生

第2回生活支援工学系学会連合大会講演予稿集 157 - 158 2004.09
旋廻渦流型人工心臓量産化のための金型形状の検討

田中隆, 岩﨑清隆, 伊藤一彦, 梅津光生

第2回生活支援工学系学会連合大会講演予稿集 203 - 204 2004.09
A novel methodology for pre-screening anti-thrombogenicity of artificial organs under physiologically identical pulsatile environments

K Iwasaki, Y Takeuchi, W Saeki, m Umezu, K Ishihara, K Imachi

the intenational journal of artificial organs 27 ( 7 ) 567 2004.07
Progress in the multi-institutional cooperative project to develop an implantable

K Imachi, Y Mitamura, T Yambe, T Matsuda, E Okamoto, M Umezu, I Nemoto,A Mimaki

the intenational journal of artificial organs 27 ( 7 ) 571 2004.07
Hemodynamic effect of the left or right ventricular assistance by a mechanical myocardial assist system

Y Shiraishi, T Yambe, K, Sekine,T Yamaguchi, S Shibata, Y Saijo, M, Watanabe, Nagatoshi, H Aoki, S Ito, M Umezu,S, Tanaka, Okamoto,D Ogawa, Olegario, M Yoshizawa, Q Wang, Duan,H Liu, F Sato,T Tanaka, S Nitta, K, Tabayashi, H Sasada

the intenational journal of artificial organs 27 ( 7 ) 575 2004.07
Development of a coronary mock simulator to evaluate the effectiveness of coronary artery bypass grafting anastomosis

M Umezu, J Kawai, J Suehiro, H Niinami, M Arita, Y Shiraishi, K Iwasaki

the intenational journal of artificial organs 27 ( 7 ) 578 2004.07
Development of a completely decellularized and precellularized functional porcine aortic valve

K Iwasaki, S Ozaki, T, Nakazawa, T Kawai, Y Imai, M Ishihara, Y Ohzeki, Y Morimoto, M Kikuchi, M Umezu

the intenational journal of artificial organs 27 ( 7 ) 594 2004.07
Development of fully implantable undulation pump ventricular assist system under multi-institutional cooperative project

K Imachi, Y Miyamura, T Yambe, T Matsuda, E Okamoto, M Umezu,A Suzuki, I Nemoto,A Miyaki

ASAIO Journal,ASAIO Abstracts for the 50th Anniversary Conference 126 2004.06
Inexpensive ventricular assist system(VAS) for short time use by spiral vortex(SV) pump

M Umezu, K Iwasaki, T Tanaka, K Itoh, K Imachi, K Ishikawa, C X Ye

ASAIO Journal,ASAIO Abstracts for the 50th Anniversary Conference Washington DC 141 2004.06
A new and more practical approach for in vitro durability test for rotary lvas pump

T Kitano, T Tokuno, K Kaneko, K, Yamazaki, S Kihara, M Umezu, K Iwasaki, C Conti

ASAIO Journal,ASAIO Abstracts for the 50th Anniversary Conference,Washington DC 133 2004.06
In vitro accelerated calcification tester for biomaterials using real blood

K Iwasaki, M Umezu, K Imachi

ASAIO Journal,ASAIO Abstracts for the 50th Anniversary Conference,Washington DC 170 2004.06
CMC内蔵型シリコン管の製作と性能

朴栄光, 梅津光生, 松本徹, 岩﨑清隆, 田中隆, O Medvedev, 青見茂之, 元島栖二

第15回カーボンマイクロコイル(CMC)研究会 37 - 40 2004.06
CMCの医療機器応用への期待

梅津光生, 朴栄光, 松本徹, 岩﨑清隆, 田中隆, O Medvedev, 藤江正克, 高西淳夫, 山川宏, 元島栖二

第15回カーボンマイクロコイル(CMC)研究会 19 - 22 2004.06
医工産の連携について/生命理工学専攻にみる医工連携の実践的教育、研究

第79回日本医科器械学会大会パネルディスカッション/医療技術産業のフロンティアへの挑戦/東京国際フォーラム 2004.05
血液循環モデルの人工臓器評価への応用

梅津光生, 岩﨑清隆, 白石泰之, 有田誠, 田中隆, 堀切芳一, 銭逸, 野口康雄

第43回日本ME学会大会、日本ME学会誌生体医工学 42 412 2004.05
革新的動的バイオリアクター技術による再生・自己化促進型組織大動脈弁の開発

岩﨑清隆, 尾崎重之, 中澤剛, 今井裕一, 川井貴裕, 石原雅之, 大関泰宏, 守本裕司, 菊地眞, 海老根東雄, 梅津光生

第43回日本ME学会大会、日本ME学会誌生体医工学 42 246 2004.05
パルスフォトメトリ装置用構成装置の研究

石川則夫, 岩﨑清隆, 佐伯航, 竹内有里, 小林直樹, 青海達也, 大西悠介, 伊藤一彦, 武田朴, 梅津光生

第43回日本ME学会大会、日本ME学会誌生体医工学 42 351 2004.05
人工心筋を用いた心機能補助時の左心室壁に対する影響の工学的基礎検討

白石泰之, 山家智之, 青木秀宜, 永利潤, 伊藤慎二, 吉田敬, 梅津光生, 田中秀治, 岡本英治, 西條芳文, 王慶田, 段旭東, 劉紅箭, 仁田新一, 小川大祐, ポール・オレガリオ, 田中明, 吉澤誠, 佐藤文博, 松木英敏, 圓山重直, 早瀬敏幸, 佐々田比呂志

第43回日本ME学会大会、日本ME学会誌生体医工学 42 420 2004.05
埋込型補助心臓の実用化のための多施設間共同研究

井街宏, 三田村好矩, 岡本英治, 山家智之, 梅津光生, 松田武久, 鈴木晃, 根元功, 三牧秀明

第43回日本ME学会大会、日本ME学会誌生体医工学 42 422 2004.05
高周波バルーンカテーテルによる均一輪状焼灼の理論的解析

高岡元紀, 山崎善治, 池田智彦, 川村明, 野口康雄, 岩﨑清隆, 梅津光生

第43回日本ME学会大会、日本ME学会誌生体医工学 42 697 2004.05
オシロメトリック信号の解析を目的とした血圧-空気圧の計算モデルの開発

藤本哲男, 臺寛史, 岡本京子, 増本憲泰, 白石泰之, 田中隆, 梅津光生

平成15年度生体医工学研究センター公開研究成果報告会、循環器系障害発生の解明及び治癒に対する流体力学及び分子生物学的研究講演要旨集芝浦工大先端工学研究機構学術フロンティアセンター 1 - 6 2004.03
低価格化補助人工心臓の試み

梅津光生, 岩﨑清隆, 吉田敬, 須藤知浩, 田中隆, 伊藤一彦, 藤本哲男

平成15年度生体医工学研究センター公開研究成果報告会、循環器系障害発生の解明及び治癒に対する流体力学及び分子生物学的研究講演要旨集芝浦工大先端工学研究機構学術フロンティアセンター 55 - 58 2004.03
Static analysis of annuloplasty rings sutured on an annulus model of the mitral valve: Comparison between the Duran ring and the Carpentier Classic ring

Makoto Arita, Hitoshi Kasegawa, Mitsuo Umezu

Journal of Artificial Organs 7 ( 1 ) 30 - 36 2004

　View Summary

A novel in vitro evaluation system was developed to study the performance of newly developed and conventional annuloplasty rings. Using this system, a comparative study between the Duran flexible ring and the Carpentier Classic (rigid) ring was conducted with the aim of achieving a better understanding of these devices and of providing surgeons with better criteria for selecting the most appropriate annuloplasty ring. It was possible to obtain quantitative data using a microscope and a load cell to measure valve orifice area and tensile load on the valve annulus, respectively. Among the results were the findings that the orifice area of the rigid ring was smaller by 12.0% than that of the flexible ring and that in both rings the load was greater in the posterior region than in the anterior region. Further analysis using a beam model demonstrated that the stress applied to the sutures of the rigid ring is higher than that for the flexible ring in terms of shearing force and bending moment of the ring. This pilot study yielded several important findings: the ability of a ring to maintain valve orifice area is observable
larger loads are applied to the posterior annulus than to the anterior annulus
and it is possible to clarify and compare the characteristics of various types of annuloplasty rings.

DOI PubMed

Scopus

7

Citation

(Scopus)
ナノテクを応用した人工臓器開発の新しい地平

山家智之, 堀義生, 白石泰之, 井口篤志, 田林晄一, 芳賀洋一, 江刺正喜, 吉澤誠, 田中明, 松木英敏, 佐藤文博, 川野恭之, 羅雲, 高木敏行, 早瀬敏幸, 圓山重直, 王慶田, 段旭東, 仁田進一, 井街宏, 佐々田比呂志, 佐藤英明, 岡本英治, 久保豊, 大坂元久, 梅津光生, 本間大, 前田剛

未来材料,(株)エヌ・ティー・エス 4 ( 8 ) 30 - 37 2004
Effect of the elastic conditions around a stentless valvular bioprosthesis on opening behavior

Fujimoto T, Kasegawa D, Shiraishi Y, Iwasaki K, Arita M, Tamaka T, Umezu M

The Japanese Society for Artificial organs 2004 17 133 - 136 2004
パルスフォトメトリ装置用校正装置の研究

武田朴, 岩崎清隆, 佐伯航, 竹内有理, 小林直樹, 須崎裕典, 青海龍也, 大西悠介, 伊藤一彦, 石川則夫, 梅津光生

医器学 74 ( 10 ) 598 - 599 2004
生命理工学専攻にみる医工連携の実践的教育・研究

梅津光生, 岩崎清隆, 桜井靖久, 岡野光夫

第16回バイオエンジニアリング講演会講演論文集 337 - 338 2004.01
心臓病の治療効果評価のための左心系モデルの開発、

野口康雄, 梅津光生, 岩崎清隆

第16回バイオエンジニアリング講演会講演論文集 63 - 64 2004.01
新規の完全大気非接触型拍動流循環回路による人工臓器のin vitro 抗血栓性評価方法の確立に向けての挑戦

岩崎清隆, 梅津光生, 佐伯航, 石原一彦, 井街宏, 桜井靖久

第16回バイオエンジニアリング講演会講演論文集 217 - 218 2004.01

CiNii
医用高分子材料の長期血液循環使用下で問題となるカルシウム沈着特性のin vitro 評価試験手法の新開発、

岩崎清隆, 梅津光生, 井上旭, 長谷川厚, 曽根大助, 井街宏

16回バイオエンジニアリング講演会講演論文集 219 - 220 2004.01
Spiral Vortex 型血液ポンプ内の3次元流れ解析に向けて-PIV可視化解析及び数値流体モデルによる検討

八木高伸, Willam Yang, 長沼寛樹, 佐藤芳行, 岩崎清隆, 梅津光生

第16回バイオエンジニアリング講演会講演論文集 245 - 246 2004.01
三次元心筋組織構築のための灌流培養装置の開発

坂口勝久, 清水達也, 岩崎清隆, 桜井靖久, 岡野光夫, 梅津光生

第16回バイオエンジニアリング講演会講演論文集 445 - 446 2004.01
脱細胞化異種大動脈弁の開発:拍動循環下でのマイクロ波均一照射による完全脱細胞化および拍動循環での組織再内皮細胞化手法の検討

岩崎清隆, 尾崎重之, 中澤剛, 今井裕一, 川井貴裕, 石原雅之, 守本祐司, 菊池眞, 梅津光生

第16回バイオエンジニアリング講演会講演論文集 437 - 438 2004.01
自分が使いたくなる再生型人工臓器の開発、及び人工臓器の開発のスピード化に寄与する協会領域の性能評価試験方法の確立に向けて

岩﨑清隆, 梅津光生

第32回人工心臓と補助循環懇話会 52 2004.01
機械式心室補助装置による局所的心筋収縮補助方法の検討

白石泰之, 山家智之, 柴田宗一, 山口済, 王慶田, 段旭東, 洪蘭, 劉紅箭, 沙偉, 永利潤, 青木秀宜, 吉田敬, 梅津光生, 小川大祐, ポールオレガリオ, 田中明, 吉澤誠, 田中秀治, 岡本栄治, 仁田新一

第32回人工心臓と補助循環懇話会 67 2004.01
Biomedical engineering for Cardiovascular Surgery ,Workshop on “ Advances in Biotechnology and Bioengineering”

藤本哲男, 臺寛史, 岡本京子, 増本憲泰, 白石泰之, 田中隆, 梅津光生

Salt Lake City Utah,USA 2004.01
Multiple purpose simulator using a natural porcine mitral valve

Makoto Arita, Sumihiro Tono, Hitoshi Kasegawa, Mitsuo Umezu

Asian Cardiovascular and Thoracic Annals 12 ( 4 ) 350 - 356 2004

　View Summary

An in vitro pulsatile simulator with a porcine mitral valve was developed in order to simulate physiologic and diseased mitral valve conditions. Evaluation of these conditions was conducted from a hydrodynamic and annulus behavior point of view. We found it possible to simulate mild "mitral valve prolapse" and to obtain quantitative data related to the condition. The diseased condition produced a 40% greater regurgitant volume than that observed under the normal condition (p &lt
0.0001). Regarding the leakage volume, the diseased condition exhibited about 2.6 times more leakage than the normal condition. The mitral valve simulator proposed in this study is considered fairly stable with respect to both hemodynamics and the behavior of the annulus, and it is an adequate simulator for modeling various types of normal and diseased mitral valve conditions.

DOI PubMed

Scopus

10

Citation

(Scopus)
OpenMRI下脳外科手術におけるナビゲーションシステムの精度及び操作性向上に関する研究

長嶋義昭, 廣瀬左智雄, 鈴川浩一, 苗村潔, 高信英明, 村垣善浩, 伊関洋, 梅津光生, 高倉公朋

第12回日本コンピュータ外科学会大会、第13回コンピュータ支援画像診断学会大会合同論文集 175 - 176 2003.12
In vitro evaluating system for prosthetic heart valves

Tetsuo Fujimoto, Yuichi Tsutsumi, Daisuke Kawaguchi, Yasuyuki Shiraishi, Kiyotaka Iwasaki, Makoto Arita, Mitsuo Umezu

芝浦工業大学学術フロンティア推進事業2002年度研究成果報告,芝浦工業大学先端工学研究機構 17 - 26 2003.12
In Vitro Biocompatibility test under identical human hemodynamics

Mitsuo Umezu, Kiyotaka Iwasaki, Wataru Saeki, Kazuhiko Ishihara

8th Japan international SAMPE symposium and exhibition SAMPE,2003 2003.11
Mock circulatory system for biocompatibility test as a replacement of animal experiment

Mitsuo Umezu, Kiyotaka Iwasaki

6th Polish-Japanese symposium on bio-medical engineering 43 - 44 2003.10
A novel in vitro device to investigate a calcification mechanism on cardiovascular implants

Kiyotaka Iwasaki, Mitsuo Umezu, Kou Imachi

6th Polish-Japanese symposium on bio-medical engineering 41 - 42 2003.10
大動脈弁置換用ブタ組織弁の脱細胞化手法の検討

中澤剛, 岩崎清隆, 尾崎重之, 守本裕司, 石原雅之, 梅津光生

第14回バイオフロンティア講演会講演論文集 2003 ( 14 ) 35 - 36 2003.09

CiNii
Risk and benefitのバランス感覚を支える人工臓器のIn Vitro性能評価のあり方

梅津光生, 岩崎清隆, 白石泰之, 有田誠, 堀切芳一, 田中隆, 馮忠剛, 藤本哲男, 桜井靖久

人工臓器 32 ( 2 ) s-16 2003.09
体内植え込み型補助人工心臓に関する社会的・経済的諸問題とその対策

山崎健二, 木原信一郎, 津久井宏行, 川合明彦, 秋元剛秀, 田鎖治, 斉藤聡, 石戸谷浩, 西田博, 梅津光生, 富岡淳, 山崎俊一, 遠藤真弘, 黒澤博身

人工臓器 32 ( 2 ) s-8 2003.09
完全大気日接触環境下で生体内圧力・流量を模擬したin vitro 血液適合性評価回路の開発

佐伯航, 岩崎清隆, 梅津光生, 桜井靖久, 石原一彦, 井街宏

人工臓器 32 ( 2 ) s-146 2003.09
組織細胞工学を応用したハイブリッド大動脈弁の研究開発

尾崎重之, 海老根東雄, 大関泰宏, 田村進, 小堺浩一, 村瀬俊文, 小林陽一, 前原正明, 守本祐司, 菊池眞, 石原雅之, 岩崎清隆, 梅津光生

人工臓器 32 ( 2 ) s - 35 2003.09
温度応答性パターン化表面による共培養細胞シートの回収と細胞機能の解析

津田行子, 菊池明彦, 大和雅之, 桜井靖久, 梅津光生, 岡野光夫

第32回医用高分子シンポジウム、社団法人高分子学会第32回医用高分子シンポジウム講演要旨集 65 - 66 2003.08
Development of an inexpensive Chang’s artificial heart

M Umezu

World congress on medical physics and biomedical engineering, Sydney, Australia CD-R 2003.08
Development of an in vitro evaluation system for mitral annuloplasty, Poster

H Doi, M Okuda, M Arita,T Yogi, K, Iwasaki H, Kasegawa, M Umezu

World Congress on Medical Physics and Biomedical Engineering Poster 2003.08
Dinamic and static evaluation of two types of annuloplasty rings at mitral position using a mock circuit with fresh porcine valve

Mitsuo Umezu, Kiyotaka Iwasaki, Makoto Arita, Muneomi Okuda, Hirohumi Doi, Takanobu Yagi, Hitoshi Kasegawa, Tetsuo Fujimoto

The international Journal of Artificial Organs Europian Society for Artificial Organs 26 ( 7 ) 2003.07
A novel methodology to investigate a calcification potential of polymeric cardiovascular biomaterials under accelerated condition,

Kiyotaka Iwasaki, Mitsuo Umezu, Akira Inoue, Kouichirou Marume

the internationa journal of artificial organs,Europian society for artificial organs 26 ( 7 ) 2003.07
New multi-institutional cooperative project to develop an implantable ventricular assist system in Japan

K Imachi, Y Mitamura, T Yambe, T Matsuda, E Okamoto, M Umezu,A Suzuki, I Nemoto,A Mimaki

the internationa journal of artificial organs,Europian society for artificial organs 26 ( 7 ) 2003.07
Development of a mechanical myocardial assist system for ventricular support

Y Shiraishi, T Yambe, Q, T Wang, S Nanka, Y Saijo, S nitta,a Yanaka, M Yoshizawa, S Maruyama, t Hayase, S Kawano,T Ohashi, T Takagi, Y Luo, M Esashi, T Haga, F Sato, Okamoto,H Aoki, J Kawai, Nagatoshi, J Suehiro, M Umezu,D Homma

the internationa journal of artificial organs,Europian society for artificial organs 26 ( 7 ) 2003.07
Effect of bifurcation on pressure loss in aortofemoral prosthetic y grafts

T Fujimoto, H Ohasi, K Arai, K, Okamoto,H Iwamura, Y Shiraishi, M Umezu

the internationa journal of artificial organs,Europian society for artificial organs 26 ( 7 ) 2003.07
肝細胞のアルブミン産生を増強しうるパターン化共培養司式の作製

津田行子, 菊池明彦, 大和雅之, 桜井靖久, 梅津光生, 岡野光夫

第6回日本組織工学会一般口演第6回日本組織工学会プログラム・抄録集 88 2003.06
循環器の再生医療:座長

2003.06
拍動循環下でのマイクロ波照射によるブタ大動脈弁の完全脱細胞化手法の開発

岩﨑清隆, 尾崎重之, 守本裕司, 中澤剛, 石原雅之, 菊地眞, 梅津光生

第6回日本組織工学会第6回日本組織工学会プログラム・抄録集 106 2003.06
心筋細胞再構築のための機械力学的伸展培養装置の開発及びその機能評価

関根卓也, 清水達也, 岡野光夫, 岩﨑清隆, 桜井靖久, 梅津光生

第6回日本組織工学会第6回日本組織工学会プログラム・抄録集 125 2003.06
動物実験代替システムによる人工臓器の医工学評価技術

梅津光生, 岩﨑清隆

日本エム・イー学会誌生体医工学第41巻特別号第42回日本エム・イー学会大会プログラム論文集 84 2003.06
拍動バイオリアクターによるブタ大動脈弁の脱細胞播種の検討

岩﨑清隆, 尾崎重之, 中澤剛, 今井裕一, 守本裕司, 石原雅之, 菊地眞, 梅津光生

日本エム・イー学会誌生体医工学第41巻特別号第42回日本エム・イー学会大会プログラム論文集 80 2003.06
人工的心筋補助装置の開発と基礎特性

白石泰之, 岡本英治, 山家智之, 南家俊介, 西條芳文, 仁田新一, 青木秀宜, 斎藤勇二, 吉田敬, 八木高伸, 長嶋義昭, 川合潤子, 末広淳一, 梅津光生, 小川大祐, 田中明, 吉澤誠, 佐藤文博, 羅雲, 圓山重直, 芳賀洋一, 江刺正善, 早瀬敏幸, 田林晄一

日本エム・イー学会誌生体医工学第41巻特別号第42回日本エム・イー学会大会プログラム論文集 358 2003.06
加速度センサーを用いた人工心臓装着心の心拍検出

斎藤逸郎, 鎮西恒雄, 阿部裕輔, 磯山隆, 望月修一, 河野明正, 小野俊哉, 岩﨑清隆, 中川英元, 馬場敦, 瀧浦晃基, 尾関俊長, 三井美絵, 井街宏

日本エム・イー学会誌生体医工学第41巻特別号第42回日本エム・イー学会大会プログラム論文集 555 2003.06
Numerical prediction of hydrodynamic Performance inside centrifugal blood pumps

Wei YANG, Mitsuo UMEZU

日本エム・イー学会誌生体医工学第41巻特別号第42回日本エム・イー学会大会プログラム論文集 355 2003.06
ナノテク集積人工心筋開発プロジェクト

山家智之, 白石泰之, 井口篤志, 田林晄一, 芳賀洋一, 江刺正喜, 吉澤誠, 田中明, 松木英敏, 佐藤文博, 川野恭之, 羅雲, 高木敏行, 早瀬敏幸, 圓山重直, 王慶田, 段旭東, 仁田新一, 岡本英治, 久保豊, 大坂元久, 梅津光生

循環制御 24 ( 2別冊 ) 2003.06
Electrically communicating three-dimensional cardiac tissue mimic fabricated by layered cultured cardiomyocyte sheets

Tatsuya Shimizu, Masayuki Yamato, Takumitsu Akutsu, Takahiko Shibata, Yuki Isoi, Akihiko Kikuchi, Mitsuo Umezu, Teruo Okano

東京女子医科大学先端生命医科学研究所報告 24 332 - 339 2003.05
コロナリーステントの工学的評価

梅津光生, 岩﨑清隆, 堀切芳一, 有田誠

第20回ニッポンMetallic Stents and Grafts研究会研究発表集,IVR Unternational radiology,Metallic Stentの現況と進歩Ⅴ,ニッポン血液造営・インターベンションナルラジオロジー学会雑誌 18 48 - 49 2003.04
大動脈弁置換用を目指したブタ組織弁の脱細胞化手法の検討及びin vitro拍動下での細胞播種用バイオリアクターの開発

岩﨑清隆, 尾崎重之, 中澤剛, 今井裕一, 守本裕司, 石原雅之, 菊地眞, 梅津光生

日本機械学会関東支部第9期総会講演会公園論文集、日本機械学会関東支部 83 - 86 2003.03
低価格旋回渦流型拍動血液ポンプの製作法の検討

吉田敬, 岩﨑清隆, 小崎哲也, 梅津光生, 桜井靖久

日本機械学会関東支部第9期総会講演会公園論文集、日本機械学会関東支部 91 - 92 2003.03
血液循環の人工臓器に関する開発と性能評価

藤本哲男, 川口大輔, 白石泰之, 岩﨑清隆, 梅津光生

日本機械学会関東支部第9期総会講演会公園論文集、日本機械学会関東支部 101 - 102 2003.03
医工連携に基づくBME研究の新展開 New biomedical engineering research based on a collaboration between medical-engineering institutions,:

梅津光生, 岩﨑清隆, 鈴川浩一, 白澤直人, 井上宗寛, 桜井靖久, 岡野光夫

日本機械学会関東支部第9期総会講演会公園論文集、日本機械学会関東支部 103 - 104 2003.03
ブタ僧帽弁を用いた弁膜疾患の機械シミュレータの開発と人工臓器開発への応用、平成14年度文部科学省学術フロンティア推進事業採択生体医工学研究センター公開シンポジウム、(循環器系障害発生の解明及び注油に対する流体力学及び分子生物学的研究

梅津光生, 岩﨑清隆, 有田誠, 奥田宗臣, 土井博文, 加瀬川均, 藤本哲男

平成14年度文部科学省学術フロンティア推進事業採択生体医工学研究センター公開シンポジウム、(循環器系障害発生の解明及び注油に対する流体力学及び分子生物学的研究)講演要旨集、芝浦工業大学先端工学研究機構生体医工学研究センター 17 - 20 2003.03
温度応答性培養皿及び伸展培養デバイスを用いた組織工学的手法による心筋組織の再構築及びその機能評価

関根卓也, 清水達也, 大和雅之, 菊池明彦, 梅津光生, 岡野光夫

第12回インテリジェント材料/システムシンポジウム講演要旨集(社)未踏科学技術協会インテリジェント材料・システムフォーラム 60 2003.03
人工臓器のIn vitro における性能評価-人工弁を中心とした臨床条件の検討について-、平成14年度文部科学省学術フロンティア推進事業採択生体医工学研究センター公開シンポジウム、(循環器系障害発生の解明及び注油に対する流体力学及び分子生物学的研究)

川口大輔, 堤裕一, 白石泰之, 岩﨑清隆, 梅津光生

平成14年度文部科学省学術フロンティア推進事業採択生体医工学研究センター公開シンポジウム、(循環器系障害発生の解明及び注油に対する流体力学及び分子生物学的研究)講演要旨集、芝浦工業大学先端工学研究機構生体医工学研究センター 21 - 26 2003.03
In vivo evaluation of a MPC polymer coated continuous flow left ventricular assist system

Shin ichiro Kihara, Kenji Yamazaki, Kenneth N Litwak, Philip Litwak, Marina V Kameneva, Hiroyuki Ushiyama, Toshimasa Tokuno, David C Borzelleca, MitsuoUmezu, Jun Tomioka, OsamuTagusari, TakehideAkimoto, HitoshiKoyanagi, HiromiKurosawa, Robert L

Artificial Organs 27 ( 2 ) 2003.02 [Refereed]
人工臓器のin vitro抗血栓性評価を目的とした完全大気非接触型拍動流試験回路の開発

岩﨑清隆, 梅津光生, 佐伯航, 石原一彦, 井街宏

第15回バイオエンジニアリング講演会、大阪大学、2003.1月21日〜22日第15回バイオエンジニアリング講演会、大阪大学、バイオエンジニアリング部門企画 8 2003.01
冠動脈ステントの力学的特性試験装置の開発

梅津光生, 岩﨑清隆, 有田誠, 堀切芳一

第15回バイオエンジニアリング講演会、大阪大学、2003.1月21日〜22日第15回バイオエンジニアリング講演会、大阪大学、バイオエンジニアリング部門企画 8 2003.01
新規組織工学的手法による3次元心筋組織の作成と機能評価

井上宗寛, 関根卓也, 大伴佳司, 清水達也, 岡野光夫, 梅津光生

第15回バイオエンジニアリング講演会、大阪大学、2003.1月21日〜22日第15回バイオエンジニアリング講演会、大阪大学、バイオエンジニアリング部門企画 8 2003.01
人工心臓の耐久性を予測する上での留意点

梅津光生, 岩﨑清隆, 桜井靖久

第31回人工心臓と補助循環懇話会、宮城蔵王、2003、1月24日〜25日[ 第31回人工心臓と補助循環懇話会 21 2003.01
機械工学的手法による配向心筋細胞シートの作成とその将来応用

関根卓也, 井上宗寛, 大伴佳司, 清水達也, 岩﨑清隆, 岡野光夫, 梅津光生

第31回人工心臓と補助循環懇話会、宮城蔵王、2003、1月24日〜25日第31回人工心臓と補助循環懇話会 77 2003.01
長期機械的寿命の実現と同時にカルシウム沈着の長期抑制に成功した人工心臓用高分子製弁Jellyfish弁の開発

岩﨑清隆, 梅津光生, 井街宏, 阿部裕輔, 鎮西恒雄, 磯山隆, 斎藤逸郎

第31回人工心臓と補助循環懇話会、宮城蔵王、2003、1月24日〜25日第31回人工心臓と補助循環懇話会 81 2003.01
心筋収縮補助装置(人工心筋)のよる血行力学的効果の基礎検討

白石泰之, 岡本英治, 山家智之, 南家俊介, 西條芳文, 仁田新一, 青木秀宜, 渡邊聡亮, 川合潤子, 八木高信, 斎藤勇二, 小崎哲也, 吉田敬, 梅津光生, 田中明, 吉澤誠, 圓山重直, 芳賀洋一, 江刺正善, 早瀬敏幸

第31回人工心臓と補助循環懇話会、宮城蔵王、2003、1月24日〜25日第31回人工心臓と補助循環懇話会 97 2003.01
人工臓器の血液適合性評価を目的とした生体内圧力・流量環境に合致した完全大気非接触in vitro評価回路の開発

岩﨑清隆, 梅津光生, 佐伯航, 永倉寛子, 桜井靖久, 石原一彦, 井街宏

第31回人工心臓と補助循環懇話会、宮城蔵王、2003、1月24日〜25日第31回人工心臓と補助循環懇話会 101 2003.01
再生心筋組織の機能強化及び張力測定を可能とする伸展培養装置の開発

井上宗寛, 関根卓也, 大伴佳司, 清水達也, 岡野光夫, 梅津光生, 桜井靖久

第15回バイオエンジニアリング講演会論文集、日本機械学会 271 - 272 2003.01
人工臓器のin vitro抗血栓性評価を目的とした完全大気非接触型歯駆動流試験回路の開発

岩﨑清隆, 梅津光生, 佐伯航, 石原一彦, 井街宏

第15回バイオエンジニアリング講演会論文集、日本機械学会 361 - 362 2003.01
冠動脈ステントの力学的特性試験装置の開発

梅津光生, 岩﨑清隆, 有田誠, 堀切芳一

第15回バイオエンジニアリング講演会論文集、日本機械学会 363 - 264 2003.01
拍動流体外循環の臨床データより、人間総合研究センター2001年度シンポジウム(1)生命科学から見たリズム

津田行子, 菊池明彦, 大和雅之, 桜井靖久, 梅津光生, 岡野光夫

ヒューマンサイエンスコロナ社 15 ( 1 ) 64 - 66 2003.01
Investigation on the mechanical properties of contracted collagen gels as a scaffold for tissue engineering

Zhonggang Feng, M. Yamato, T. Akutsu, T. Nakamura, T. Okano, M. Umezu

Artificial Organs 27 ( 1 ) 84 - 91 2003

　View Summary

In this article the mechanical properties of contracted collagen gels were investigated thoroughly by means of uniaxial tensile test. Large type I collagen-Dulbecco's Modified Eagle Medium (DMEM) gels (each was 26 ml in volume, 1.67 mg/ml collagen concentration), each populated with about 2.5 × 106 human fibroblasts, were made in 100 mm diameter plastic dishes precoated with albumin for floating the gels in DMEM. Such identically treated gels were divided into three groups for the mechanical measurements at different culture periods (2, 4, and 10 weeks). Rapid contraction occurred within the first 3 days and then the contraction went slowly in the rest period until it reached about 13% of its original size. The stress-strain curve of the contracted collagen gels demonstrated an exponential behavior at low stress region, followed by linear region, a point of yielding, and finally an ultimate stress point at which the maximum stress was reached. The mechanical strength increased in the first few weeks and then decreased as the culture went on. It is obvious that the collagen fibrils formed and were forced to orientate to the tensile direction after the test. The stress relaxation and cyclic creep phenomena were observed. Based on the morphological analysis of transmission electron microscopy (TEM) of the gels, a nonlinear visco-elastic-plastic constitutive formula was proposed, which was able to reproduce the rheological phenomena of the gels. This experiment shows that the human fibroblasts significantly contracted collagen gels so as to achieve certain mechanical strength, which makes it possible to be a scaffold for tissue engineering. However, a further method to reinforce the mechanical strength by several folds must be considered. Meanwhile, the rheological phenomena should be taken into account in the fabrication and application of the structure.

DOI PubMed

Scopus

92

Citation

(Scopus)
Biomedical engineering approaches a function of artificial organs

M Umezu, Y Shiraishi, K Iwasaki, M Arita,T Shimizu, T Okano, Y Sakurai

[ The Bio-Era:New Frontiers,New ChallengesProgram and Abstract Handbook] 81 - 82 2002.12
Investigation of the anastomosis method for coronary arterial bypass grafting

J Kawai, M Arita,T Akutsu, Y Noguchi, H Niinami, M Umezu

[ The Bio-Era:New Frontiers,New ChallengesProgram and Abstract Handbook] 96 2002.12
An inexpensive pulsatile blood pump:Fabrication strategies and in vitro reliable methodology to evaluate blood compatibility

K Iwasaki, M Umezu, T Tsujimoto, K, Yoshida,W Saeki, Y Qian, K Ishihara, K Imachi, Y Sakurai

[ The Bio-Era:New Frontiers,New ChallengesProgram and Abstract Handbook] 129 2002.12
OpenMRI下脳外科手術におけるナビゲーションシステムの操作性向上に関する研究

鈴川浩一, 長嶋義昭, 苗村潔, 高信英明, 杉浦円, 南部恭二郎, 村垣善浩, 梅津光生, 伊関洋, 高倉公朋

[コンピューター外科学会大会.Dec.2002] 59 - 60 2002.12
低侵襲手術用多自由度脳ヘラ型マニピュレータの開発第3報臨床に向けたトータルなシステムの構築

岡本淳, 藤江正克, 梅津光生, 伊関洋

第12回コンピュータ支援画像診断学会大会、第11回日本コンピュータ外科学科大会合同論文集 125 - 126 2002.12
高分子製人工弁Jellyfish弁の開発:カルシウム沈着の抑制と長期耐久性の実現

岩﨑清隆, 梅津光生, 井街宏, 阿部浩輔, 鎮西恒雄, 磯山隆, 斎藤逸郎

人工臓器[第40回日本人工臓器学会、札幌] 31 ( 2 ) S - 27 2002.10
Biomechanical approach to evaluate a function of artificial organs

Umezu.Mitsuo, Shiraishi.Yasuyuki, Iwasaki.Kiyotaka, Arita.Makoto, Shimizu.Tatsuya, Okano.Tetsuro

人工臓器, 第40回日本人工臓器学会 31 ( 2 ) s - 51 2002.10
In vitro evaluating system for prosthetic heart valves in a case of the Jyros Valve

Fujimoto,T, Tsutsumi,Y, Shiraishi,Y, Iwasaki,K, Yoshida,M, Umezu,M, J.Begg

Biocybernetics and Biomedical Engineering 2002 22 ( 4 ) 46 2002.09
The improved jellyfish valve: Durability enhancement with sufficient blood compatibility

K Iwasaki, M Umezu, Y Abe, T Chinzei, T Isoyama, Saito, I, M Ishimaru, K Imachi

ASAIO JOURNAL 48 ( 5 ) 532 - 537 2002.09 [Refereed]

　View Summary

The Jellyfish Valve is one of the most promising polymer valves for artificial hearts. The present problems to be solved are 1) how to prevent a membrane fracture and 2) how to eliminate a calcification, because both of these problems were observed in experiments with goats after 312 days and 414 days of pumping. Finite element analysis demonstrated that mechanical tensile strain induced in the membrane at valve closure was clearly consistent with the fracture location as well as calcification area in in vivo experiments. Based on this finding, a new valve seat with an additional concentric ring 14 mm in diameter and 0.5 mm in width was finally developed. The maximum strain was dramatically reduced to 52% by the design improvement. Moreover, accelerated fatigue tests demonstrated that the improved valve was 10 times more durable as compared with the original valve, which was equivalent to an in vivo duration of 8.3 years. In animal experiments, including 31days and 46 days use in a total artificial heart (TAH), no thrombus was found despite the lack of anticoagulant or antiplatelet therapies. These results indicate that the improved Jellyfish Valve might be one of the most durable polymer valves, able to perform in artificial hearts for a long period of time.

DOI
Left Ventricle simulator for surgeons’support

Umezu,M, Arita,M, Iwasaki,K, Shiraishi,Y, Tono,S, Uchida,K

Biocybernetics and Biomedical Engineering,2002 22 ( 4 ) 47 - 53 2002.08
拡張力の異なる自己拡張型ステントの血管内留置後の血管組織反応の比較:ミニ豚実験

高宮誠, 田中良一, 梅津光生, 有田誠, 大森謙一

第8回日本血管内治療学会,血管内治療の今後の展望—治療成績の更なる向上を目指して— 53 2002.07
Development of a novel in-vitro closed circuit for anti-thrombogenic tests of cardiac prostheses under physiologic hemodynamic conditions

Iwasaki,K, Umezu,M, Minami,S, Imachi,K, C X Ye

ASAIO journal 48 ( 2 ) 164 2002.06
コロナリーステントの工学的評価

梅津光生, 有田誠, 大森謙一, 堀切芳一

、第20会日本Metallic Stents and Grafts研究会日本Metallic Stents and Grafts研究会プログラム・抄録,pp34 34 2002.06
低侵襲手術用多自由度脳ヘラ型マニピュレータの開発第2報プロトタイプによる動物実験評価

岡本淳, 藤江正克, 梅津光生, 伊関洋

日本機械科学会ロボティクスメカトロニクス部門ロボティクス・メカトロニクス講演会 CDRom収録 2002.06
Implications for the establishment of accelerated fatigue test protocols for prosthetic heart valves

K Iwasaki, M Umezu, K Iijima, K Imachi

ARTIFICIAL ORGANS 26 ( 5 ) 420 - 429 2002.05 [Refereed]

　View Summary

The goal of this research is to establish a reliable methodology for accelerated fatigue tests of prosthetic heart valves. A polymer valve was the subject, and the influence of various drive parameters on durability was investigated in three different machines. Valve lifetime was notably shortened by increasing the cyclic rate or stroke even though the maximum pressure difference at valve closure was maintained at 120 mm Hg. These results demonstrate that adjustment of the maximum transvalvular pressure is not sufficient to ensure tests are conducted under the same conditions and indicate that measurement of the dynamic load would be more efficacious. Moreover, the locations of tears sustained in the accelerated tests differed from those encountered in an animal experiment although in both cases the locations were entirely consistent with the areas of strain concentration revealed by finite element analysis. These findings should be discussed during a revision of ISO 5840.
In vitro cardification of UHMWPE/PU composite membrane

Z.G.Tang, S.H.Teoh, W.McFarlane, L.A.Poole-Warren, M.Umezu

Materials Science and EngineeringC 2002 149 - 152 2002.04
心臓血管外科支援用循環シミュレータ

梅津光生, 内田浩司, 有田誠, 岩﨑清隆, 白石泰之, 桜井靖久

第14回バイオエンジニアリング講演会 2002.03
Spiral vortex ventricular assist device :Its history and present status ,2nd Wasda-Renji Hospital BioMedical Engineering Symposium,Shanghai.China,March.20

M.Umezu, CX.Ye, A.Nugent, T.Nakamura, K.Iwasaki, M.Arita, Y.Shiraishi, T.Tanaka, K.Imachi, K.Ishihara, V.P.Chang

Proceedings 2nd Wasda-Renji Hospital BioMedical Engineering Symposium 6 - 7 2002.03
A challenge to develop an Inexpensive spiral vortex Pump, 2nd Wasda-Renji Hospital BioMedical Engineering Symposium,Shanghai.China,March.2002

K.Iwasaki, M.Umezu, T.Tsujimoto, W.Saeki, A.Inoue, T.Nakazawa, M.Arita, CX.Ye

Proceedings 2nd Wasda-Renji Hospital BioMedical Engineering Symposium 8 - 10 2002.03
Developmemt of multi-purpose simulator for mitral valve disease, 2nd Wasda-Renji Hospital BioMedicalEngineering Symposium,pp14-pp15,Shanghai.China,March.20

M.Arita,K.Uchida, M.Okuda, N.Suda, H.Kasegawa, M.Umezu, T.Tanaka

Proceedings 2nd Wasda-Renji Hospital BioMedical Engineering Symposium,Shanghai.China 14 - 15 2002.03
Investigation on the mechaniacal properties of contracted collagen for the leaflets of valve prosthesis,2nd Wasda-Renji Hospital BioMedical Engineering Symposium,Shanghai.China, March.2002

Z.Feng, M.Yamato, T.Akutsu, T.Nakamura, T.Okano, M.Umezu

Proceedings 2nd Wasda-Renji Hospital BioMedical Engineering Symposium, 16 - 17 2002.03
Deveropment of a mechanical circulatory system for the support of surgical treatment with vascular graft, 2nd Wasda-Renji Hospital BioMedical Engineering Symposium,Shanghai.China, March.20

Shiraishi,Y, Saito,Y, Watanabe,T, Fujimoto,T, Umezu,M

Proceedings 2nd Wasda-Renji Hospital BioMedical Engineering Symposium 21 - 22 2002.03
薬物負荷動物実験に基づく動脈血管系負荷定量化の試み

白石泰之, 齋藤勇二, 有田誠, 藤本哲男, 梅津光生, 山家智之, 仁田新一

ヒューマンサイエンス 14 ( 2 ) 64 - 72 2002.03

CiNii
高齢者の血行動態を再現する血液循環シミュレータの開発のための検討

白石泰之, 齋藤勇二, 有田誠, 藤本哲男, 梅津光生

ヒューマンサイエンス 14 ( 2 ) 56 - 63 2002.03
カルシウム沈着抑制のための高分子製人工弁設計指標の提案

岩﨑清隆, 梅津光生, 井街宏

第14回バイオエンジニアリング講演会講演論文集、(社)日本機械学会 183 - 184 2002.03
Electrically communicating three-dimensional cardiac tissue mimic fabricated By layered cultured cardiomyocyte sheets

Shimizu,T, Yamato,M, Akutsu,T, Shibata,T, Isoi,Y, Kikuchi,A, Umezu,M, Okano,T

J Biomed Mater Res 60 110 - 117 2002.01
Fabrication of pulsatile cardiac tissue grafts using a novel 3-dimensional cell sheet manipulation technique and temperature-responsive cell culture surfaces

Shimizu,T, Yamato,M, Isoi,Y, Akutsu,T, Setomaru,T, Abe,K, Kikuchi,A, umezu,M

Circ Res,90 40 - 48 2002.01 [Refereed]
In vitro investigation of opening behavior and hydrodynamics of bileaflet valves in the mitral position

ZG Feng, T Nakamura, F Fujimoto, M Umezu

ARTIFICIAL ORGANS 26 ( 1 ) 32 - 39 2002.01 [Refereed]

　View Summary

The performance of four 25 mm bileaflet valves of different designs was evaluated in the mitral position of our own pulse simulator. With the aid of a high-speed video camera, it was demonstrated that both the St. Jude Medical (SJM) valve (Hemodynamic Plus [HP] Series, St. Jude Medical, Inc., St. Paul, MN, U.S.A.) and the CM valve (CarboMedics, Inc., Austin, TX, U.S.A.) were able to open fully and that the CM valve fluttered much snore vigorously at the fully open position than did the SJM HP valve. Conversely, neither the ATS valve (ATS Medical, Inc., Minneapolis, MN, U.S.A.) nor the On-X valve (Medical Carbon Research Institute, Austin, TX, U.S.A.) exhibited movement to a fully open configuration. The overall average opening angles of the ATS and the On-X, on 3, 4, and 5 L/min flow rate for a heart rate of 70 bpm and 5, 6, and 7 L/min for 100 bpm, were 74.8 degrees and 81.6 degrees, respectively, whereas their design opening angles were 85 degrees and 90 degrees. Pressure drops across the CM and the ATS were consistently higher than those of the On-X and the SJM HP. Closing volumes for all the valves were below 8% for a heart rate of 70 bpm. This in vitro investigation yielded the following conclusions: The ATS and On-X valves are not able to open fully in the mitral position, but this does not impair their normal function; both a larger orifice diameter and a large opening angle can decrease the pressure drop; in general, the On-X valve achieves its design goals in this experiment (i.e., it produces a lower pressure drop and lower closing volume by virtue of its large orifice and high-profile design): however, the hinge flow in the non-fully open state should be investigated further.
Analysis of flow patterns in TOYOBO-VAD at various drive condition,3rd Japan-Australia Cardiovascular Bioengineering Symposium,Sedai.Japan,November.2001

Suzuki,T, Arita,M, Oban,H, Umezu,M, Akutsu,T

Proceedings 3rd Japan-Australia Cardiovascular Bioengineering Symposium 10 - 11 2001.11
In vitro performance of “EVAHEART”, 3rd Japan-Australia Cardiovascular Bioengineering Symposium,Sedai.Japan,November. 2001

Shiraishi,Y, Saito,Y, Moriyama,H, Iwasaki,K, Umezu,M, Fujimoto,T, Miyakoshi

Proceedings 3rd Japan-Australia Cardiovascular Bioengineering Symposium 25 - 26 2001.11
Improvement of a polymer bileaflet valve to realize a low-price pulsatile blood pump, 3rd Japan-Australia Cardiovascular Bioengineering Symposium,Sedai.Japan,November. 2001

Iijima,K, Iwasaki,K, Inoue,A, Umezu,M, Imachi,K, C.X.Ye

Proceedings 3rd Japan-Australia Cardiovascular Bioengineering Symposium 29 - 30 2001.11
In vitro characteristics of coronary arterial anastomosis methods , 3rd Japan-Australia Cardiovascular Bioengineering Symposium,Sedai.Japan,November. 20

J,Kawai.,M, Arita, Noguchi,Y, Niinami,H, Umezu,M

Proceedings 3rd Japan-Australia Cardiovascular Bioengineering Symposium 34 - 35 2001.11
Enginieering analysis of the effect ff left atrial plication on giant left atrium , 3rd Japan-Australia Cardiovascular Bioengineering Symposium,Sedai.Japan,November. 2001

Uchida,K, Arita,M, Umezu,M

Proceedings 3rd Japan-Australia Cardiovascular Bioengineering Symposium 36 - 37 2001.11
Mechanical properties of contracted collagen gels as a scaffold for tissue engineering, 3rd Japan-Australia Cardiovascular Bioengineering Symposium,Sedai.Japan,November. 2001

Z.Feng, Yamato,M, Akutsu,T, Nakamura,T, Okano,T, Umezu,M

Proceedings 3rd Japan-Australia Cardiovascular Bioengineering Symposium 38 - 39 2001.11
ブタ僧帽弁を組み込んだ手術支援シミュレータ

岩﨑清隆, 内田浩司, 有田誠, 加瀬川均, 梅津光生

医用電子と生体工学、第39巻特別号2、第15回日本ME学会秋季大会論文集 61 - 62 2001.11
手術イベントレコーダの開発—手術関連情報の時系列統一と物品・薬品サポートのステージ化の検討

苗村潔, 白澤直人, 杉浦円, 久保田由美子, 上遠野千佳, 古寺紀子, 高信英明, 梅津光生, 尾崎眞, 伊関洋, 高倉公朋

第11回コンピュータ支援画像診断学会大会・第10回日本コンピュータ外科学会大会、合同論文集 127 - 128 2001.11
OpenMRI下脳外科手術におけるナビゲーションシステムのMRI磁場特性を考慮した最適化

鈴川浩一, 白川洋, 谷口拡樹, 杉浦円, 苗村潔, 高信英明, 梅津光生, 伊関洋, 高倉公朋

第11回コンピュータ支援画像診断学会大会・第10回日本コンピュータ外科学会大会、合同論文集 133 - 134 2001.11
低侵襲手術用多自由度脳ヘラ型マニピュレータの開発

岡本淳, 藤江正克, 梅津光生, 伊関洋

第11回コンピュータ支援画像診断学会大会・第10回日本コンピュータ外科学会大会、合同論文集 155 - 156 2001.11

CiNii
Innovative Approaches to Evaluate a hydrodynamic function of prosthetic heart valves and /or annuloplasty rings, 13th World Congress of international Society for Artificial Organs Eary bird session 6,Osaka,Nobember,2001

Umezu,M, Arita,M, Iwasaki,K, Shiraishi,Y

Artificial Organs 25 ( 10 ) 2001.10
From bench testing to in vivo evaluation of a compact, totally implantable , permanent electromechanical ventricular assist device (vad), 13th World Congress of international Society for Artificial Organs,Osaka,Nobember,2001

Fukada,T, Yoshida,K, Tsuboi,M, Kitazawa,A, Hoshi,H, Ohuchi,K, Nakanura,M, Umezu,M.,Fukui,Y, Sakamoto,T, Takatani,S

Artificial Organs 25 ( 10 ) 794 2001.10
Importance of dynamic-load conditions in the accelerated fatigue tests for polymer heart valves , 13th World Congress of international Society for Artificial Organs, Osaka,Nobember,2001

Iwasaki,K, Umezu,M, Imachi,K, Iijima,K

Artificial Organs 25 ( 10 ) 844 2001.10
Development of a mock circulatory system to analyze a dynamic performance of mitral annuloplasty rings, 13th World Congress of international Society for Artificial Organs, Osaka,Nobember,2001

Umezu,M.,Tono,S, Arita,m, Iwasaki,K, Shiraishi,Y, Kasegawa,H

Artificial Organs 25 ( 10 ) 847 2001.10
Development of diseased coronary artery models for a validation of coronary stent performance, 13th World Congress of international Society for Artificial Organs, Osaka,Nobember,2001

Ohmori,K, Katayose.H, Soga,S, Arita,M, Iwasaki,K, Horikiri,Y, Umezu,M

Artificial Organs 25 ( 10 ) 849 2001.10
Comparison of freestyle bioprosthesis behavior under different implanting conditions, 28th ESAO Congress “Bridging the Interdisciplinarity”,Gent-Belgium,September. 20

Fujimoto,T, Kawaguchi,D, Shiraishi,Y, Iwasaki,K, Arita,M, Yoshida,M, Umezu,M

The International Journal of Artificial Organs 24 ( 8 ) 52 2001.09
In vitro evaluation of the dynamic performance of annuloplasty rings,World Artificial-Organ Immunology and Transplantation Society,6th symposium ,Ottawa,Canada,August.20

Umezu,M, Tono.S, Arita.M, Iwasaki,K, Shiraishi,Y, Kasegawa,H

World Artificial-Organ Immunology and Transplantation Society,6th symposium 47 2001.08
人工血管置換手術における左心機能変化

鈴木洋平, 藤本哲男, 白石泰之, 有田誠, 梅津光生

日本機械学会No01-5 ,福祉工学シンポジウム講演論文アブストラクト集 339 - 342 2001.08
Design improvement of the Jellyfish valve for long-term use in artificial hearts

K Iwasaki, M Umezu, K Imachi, K Iijima, T Fujimoto

INTERNATIONAL JOURNAL OF ARTIFICIAL ORGANS 24 ( 7 ) 463 - 469 2001.07 [Refereed]

　View Summary

In a previous communication, we reported a leaflet fracture in a Jellyfish valve that was incorporated into a blood pump, after a 312-day animal implant duration. Subsequent finite element analysis revealed that the fracture location was consistent with an area of maximum strain concentration. Therefore, the aim of this study was to improve the durability in the light of these findings. Based on the engineering analysis results, a new valve seat having a concentric ring, of 0.5-mm width, located at a radius of 7.0 mm, was designed and fabricated. Accelerated fatigue tests, conducted under the conditions recommended by ISO 5840, demonstrated that the durability of this new prototype was extended by a factor of 10, as compared to the original valve. Moreover, further finite element analysis indicated that the maximum equivalent elastic strain of the proposed new valve was reduced by 52.3% as compared to the original valve. Accordingly, it has been confirmed that the modified Jellyfish valve is suitable for use in long-term artificial hearts.
Left ventricle simulator for surgeons’support

Umezu,M, Arita,M, Iwasaki,K, Shiraishi,Y, Tono,S, Kasegawa,H

63th ICB Seminar 5th Polish-Japanese Seminar On Biomedical Measurements. New Methods For Medical Diagnosis, pp15 2001.06
In vitro evaluating system for prosthetic heart valves –In a caseof the jyros valve-, 63th ICB Seminar 5th Polish-Japanese Seminar,Zakopane,Poland,2001.6

Fujimoto,T, Tsutsumi,Y, Shiraishi,Y, Iwasaki,K, Yoshida,M, Umedu,M, J, Begg

63th ICB Seminar 5th Polish-Japanese Seminar On Biomedical Measurements. New Methods For Medical Diagnosis pp16-17 2001.06
Extension of durability of jellyfish valve for lpng-term use in artificial hearts

Iwasaki,K, Unezu,M, Imachi,K, Abe,Y, Chinzei,T, Isoyama,T, Saito,I

Journal of Congestive Heart and Circulatory Suppotrt(2001) 1 ( 4 ) 293 - 297 2001.06
The improved jellyfish valve: Durability enhancement with Sufficient blood compatibility,47th Annual conference,New York,USA,2001.6

Iwasaki,K, Umezu,M.,Abe,Y, Chinzei,T, Isoyama,T, Saito,I, Kobayashi,S

ASAIO Journal 47 ( 2 ) 122 2001.04
次世代型補助人工心臓:体内埋め込み型遠心ポンプ-EVAHEART-

山崎健二, 木原信一郎, 秋元剛秀, 田鎖治, 川合明彦, 富岡淳, 梅津光生, 太田英輔, 牛山博之, 篠崎順一郎, 北野智哉, 田島功規, 青見茂之, 西田博, 遠藤真弘, 小柳仁

第9回日本定常流ポンプ研究会 30 2001.04
Method of ranking of heart valve characteristics at mitral position based on statistical Model analys

Arita,M, Iwasaki,K, Umezu,M, Yoshida,M, Fujimoto,T, Suma,H, Isomura

The Japanese Society for Artificial Organs 4 131 - 137 2001.04
高齢者の血行動態を再現する血液循環シミュレータ開発のための検討

ヒューマンサイエンス 13 ( 2 ) 95 - 101 2001.03
Influence of valve size on the hydrodynamic performance of the ATS valve

Zhonggang Feng, Takao Nakamura, Tetsuo Fujimoto, Mitsuo Umezu

Journal of Artificial Organs 4 ( 4 ) 303 - 307 2001

　View Summary

Cineradiography has revealed the presence of the "non-fully-open" phenomenon in patients with the ATS valve. Preliminary in vitro investigations have identified two contributing factors: the expanding space at the outlet of the valve, and the local flow in the pivot area. This further study was performed with the aim of elucidating these factors with respect to different sizes of the ATS valve. Three bileafet valves, ATS, CarboMedics (CM), and St. Jude Medical (SJM), with tissue annulus diameters of 25 and 29mm, were studied. The hydrodynamic performance of the valves was tested at the mitral position of our own pulse duplicator. The opening angle was measured using a high-speed video camera. All the CM and SJM valves were able to open fully in these tests, whereas the 25-mm and 29-mm ATS valves opened to 75° and 82°, respectively, despite their design maximum of 85°. The ATS exhibited the smallest pressure drop of the 29-mm valves, and the SJM the smallest of the 25-mm valves. The incomplete opening of the ATS valve might be explained by the ability of its leaflets to align themselves with the divergent outlet flow, due to its unique open-pivot design. Such a feature would also exhibit a low pressure drop, as seen in the 29mm valve. The smaller opening angle in the 25-mm valve, however, could be caused by the additional pivot flow, which might cause greater deviation of the leaflets in the smaller valve, resulting in a higher relative pressure drop.

DOI

Scopus

2

Citation

(Scopus)
Development of in-vitro evaluation system for annuloplasty rings

M. Arita, H. Kasegawa, M. Umezu

Asian Cardiovascular and Thoracic Annals 9 ( 1 ) 14 - 18 2001

　View Summary

An in-vitro system was devised to study the performance of newly developed annuloplasty rings as well as various conventional rings. The Duran Flexible Annuloplasty Ring was tested to define its characteristics and to validate the system for comparative testing. It was possible to obtain quantitative data using a microscope and a load cell to respectively measure valve orifice area and tensile load on the valve annulus. The results suggest that this apparatus could be employed to characterize the features and functional performance of other types of annuloplasty ring.

DOI

Scopus

5

Citation

(Scopus)
In Vitro Performance Tests Of A Newly-Developed Bileaflet Polymer Valve

Iwasaki,K, Umezu,M, Imachi,H, iijima,K, Morita,M, CX.Ye

10th International Conference On Biomedical Engineering pp.343-344 343 - 344 2000.12
Mechanical Characteristics Of A Flexible Mitral Annuloplasty Band

Arita,M, Kasegawa,H, Umezu,M

10th International Conference On Biomedical Engineering 289 - 290 2000.12
Visco-Elastic Characteristics Of Artificial Arteries In A Waseda Mock Circulatory System

Shiraishi,Y, Umezu,M, Fujimoto,T, Teoh,S,H

10th International Conference On Biomedical Engineering 287 - 288 2000.12
Accelerated Fatigue Testing Method For Heart Valves

Umezu,M, Iwasaki,K, Imachi,h

10th International Conference On Biomedical Engineering 51 - 52 2000.12
The Performance Of Bi-Leaflet Rotaing Valve: In-Vitro Test Results

Umezu,M.,Tsutsumi, Y.Minami,S, Arita,M, Fujimoto,T, Nakata,M, Ohba,K

The 8th Annual Meeting Of The Asian Society For Cardiovascular Surgery Program and Abstracts 2000.09
ダブルリム構造を有する改良型Jellyfish弁の動物実験による血液適応性評価

岩﨑清隆, 梅津光生, 井街宏, 藤本哲男梅津光生, 井街宏, 阿部裕輔, 鎮西恒雄, 磯山隆, 望月修一, 齋藤逸郎, 藤本哲男

人工臓器/日本人工臓器学会 29 ( 3 ) s-71 2000.08
統計的数学モデル解析に基づく僧帽弁位における人工弁特性の工学的ランク付けの試み

有田誠, 岩﨑清隆, 吉田正徳, 藤本哲男, 須磨久善, 磯村正, 梅津光生

人工臓器/日本人工臓器学会 29 ( 3 ) s-113 2000.08
機械式人工弁の弁葉回転と溶血に関する比較的検討

藤本哲男, 堤祐一, 白石泰之, 岩﨑清隆, 梅津光生

人工臓器/日本人工臓器学会 29 ( 3 ) s-119 2000.08
大動脈人工血管置換前後の血管系負荷要素の定量比較の試み

白石泰之, 有田誠, 梅津光生, 藤本哲男, 石橋和幸, 川副浩平

人工臓器/日本人工臓器学会 29 ( 3 ) s-105 2000.08
人工臓器の安全性・有効性評価の科学的方法論の確立

梅津光生, 白石泰之, 有田誠, ZGFeng, 岩﨑清隆, 吉田正徳, 藤本哲男

人工臓器/日本人工臓器学会 29 ( 3 ) s-17 2000.08
Numerical Analysis Of The Flow Characteristics Of Rotary Blood Pump

Y,S,Morsi.,W,Y,Meng.,P,J, Witt.,A,M, Ahmed, Umezu,M

Journal Of Artificial Organs/The Official Journal Of The Japanese Society For Artificial Organs 4 ( 1 ) 54 - 60 2000.08
Hydronamic Performance of ATS Valve With Respect To Different Sizes

FZ Feng, Fujimoto,T, Umezu,M

人工臓器/日本人工臓器学会 29 ( 3 ) s-72 2000.08
人工弁加速耐久試験のISO基準の拡張:高分子製人工弁への適用に関する検討

岩﨑清隆, 梅津光生, 井街宏, 藤本哲男

人工臓器/日本人工臓器学会 29 ( 2 ) 385 - 389 2000.05
高分子製人工弁の加速耐久試験確立に向けての力学的検討

岩﨑清隆, 梅津光生, 井街宏, 藤本哲男

人工臓器/日本人工臓器学会 29 ( 2 ) 489 - 495 2000.05
Analysis Of Calcification Mechanism On Jellyfish Valve

Iwasaki,K, Umezu,M, Imachi,H

Proceedings 2nd Japan Australia CARDIOVASCULAR Bioengineering Symposium 41 - 42 2000.05
In-Vito Evalution System For Coronary Stents

Umezu,M, Arita,M, Iwasaki,K, Soga,S, Shiraishi,Y

Proceedings 2nd Japan Australia CARDIOVASCULAR Bioengineering Symposium 26 - 27 2000.05
Hydrodynamics Performance Of A Newly-Developed Polymer Valve For Left Ventricular Assist Devices

Kawaguchi,D, Iwasaki,K, Fujimoto,T, Umezu,M, Imachi,H, C, X,Ye

Proceedings 2nd Japan Australia CARDIOVASCULAR Bioengineering Symposium 21 - 22 2000.05
Development Of An Artificial Elastic Arteries For The Hemodynamic Simulation In The Mock Circulatory System

Shiraishi,Y, Umezu,M, Fujimoto,T, Teoh,S,H

Proceedings 2nd Japan Australia CARDIOVASCULAR Bioengineering Symposium 13 - 14 2000.05
疾病と自立:人工心臓装着患者のQOL

1999年度シンポジウムプログラム「老いの科学」/早稲田大学人間総合研究センター 17 - 19 2000.03
Extension of a Durability of Jellyfish Valve for Long-term Use in Artificial Hearts

K.Iwaski, M.Umezu, K..Imachi, Y.Abe, T.Chinzai, T.Isoyama, S.Mochizuki, I.saito, M.Isimaru, A.Baba, T.Fujimoto

Programme & Abstracts of Artificial Heart & Assist Devices 26 2000.03
ATS Prosthetic Valve Motion: An In Vitro Analysis

Tayama,E, Zhonggang,Feng, Oda,T, Tomoeds,H, Hayashiba,N, Fukunaga,S, Umezu,M, Aoyagi,S

J Heart Valve Disease 9 ( 3 ) 408 - 414 2000.03

CiNii
高速ビデオカメラを用いた人工弁の回転に関する検討

藤本哲男, 比留間信義, 堤祐一, 岩﨑清隆, 白石泰之, 梅津光生, John Begg, John Woodard

人工臓器/日本人工臓器学会 29 ( 1 ) 117 - 120 2000.02
冠動脈ステントの力学的挙動試験

梅津光生, 堀切芳一, 岩﨑清隆, 藤本哲男

人工臓器/日本人工臓器学会 29 ( 1 ) 99 - 104 2000.02
In vitro hydrodynamic characteristics among three bileaflet valves in the mitral position

Zhonggang Feng, Mitsuo Umezu, Tetsuo Fujimoto, Toshiya Tsukahara, Masakazu Nurishi, Daisuke Kawaguchi

Artificial Organs 24 ( 5 ) 346 - 354 2000

　View Summary

The non-fully open phenomenon of the advancing standard medical bileaflet heart valves (the ATS valve) are frequently observed in clinical cases, even though there is no problem with their hemodynamic function. The movement of the leaflets was affected easily by the transvalvular flow because of the unique open pivot design of the ATS valve. In this paper, a comparative in vitro hydrodynamic test was conducted among 3 different types of bileaflet valves, and the effect of different shapes of downstream conduits, which induce different transvalvular flow, on hydrodynamic performance was studied. Three bileaflet valves, the ATS valve, CarboMedics valve (CM), and St. Jude Medical valve (SJM), with an annulus diameter of 29 mm for the mitral position were chosen throughout our experiments. First, pressure drops across the valves under steady flow were measured. Then, the valves were tested at the mitral position with our pneumatically driven pulsatile pump. In this pulsatile flow study, 2 different conduits (straight shape and abrupt enlargement shape) were in turn incorporated at the downstream portion of the mitral valve. A high-speed video camera was employed to observe leaflet movements. In a steady-flow test, the ATS and the SJM produced the same pressure drop, but the CM recorded a higher value. In the pulsatile study, it was observed that the ATS leaflets did not open fully in the mitral position when the downstream conduit with an abrupt enlargement shape was incorporated. However, the CM and the SJM always indicated a fully open movement regardless of the shape of downstream conduits. When the straight downstream conduit was incorporated, the ATS produced a similar pressure drop to that of the SJM, which coincided with the steady test results. When the enlargement conduit was incorporated, however, the ATS presented the lowest pressure drop despite the non-fully open movement. The conduit shape at the valve downstream had a significant influence on the closing volume. These findings indicate that the conduit shape at the valve outlet can affect the hydrodynamic characteristics of bileaflet valves.

DOI PubMed

Scopus

21

Citation

(Scopus)
In vitro hydrodynamics of four bileaflet valves in mitral position

Z. G. Feng, M. Umezu, T. Fujimoto, T. Tsukahara, M. Nurishi, D. Kawaguchi

Asian Cardiovascular and Thoracic Annals 8 ( 1 ) 3 - 10 2000

　View Summary

Hydrodynamics of St. Jude Medical, Carbomedics, Advancing The Standard, and On-X bileaflet valves with an annular diameter of 25 mm were obtained using an in-vitro test system. Steady flow studies demonstrated different pressure drops due to differences in valve design, particularly the geometric orifice diameter and the opening angle. The On-X valve produced the least pressure drop, whereas the Carbomedics valve had the greatest pressure drop. In pulsatile flow experiments, the On-X and St. Jude Medical valves consistently produced the lowest mean positive pressure gradients, while the Carbomedics valve had the highest gradients. In spite of its parallel leaflets design, the On-X valve showed a closing volume as small as that of Carbomedics valve. The results indicate that a larger orifice diameter and greater opening angle can significantly reduce transvalvular pressure loss. This study also demonstrated that attempts to improve the hydrodynamic efficacy of the On-X valve were successful in reducing the pressure gradient as well as maintaining a low closing volume.

DOI

Scopus

2

Citation

(Scopus)
血管拡張性β遮断薬CarvedilolのQuality of Life (QOL)に及ぼす影響

橋本ひろ美, 小宅正, 池田壽雄, 五味朋子, 吉田正徳, 藤本哲男, 梅津光生, 長嶋紀一, 藤田利治, 堀美智子, 田中昌代, 藤井まき子, 松本光雄, 松本宜明, 福岡正道, 石井當男

薬剤疫学/日本薬剤疫学会 4 ( 2 ) 133 - 148 1999.12
拍動流下におけるCoronary stent の力学的評価法の検討

丹治一幸, 梅津光生, 藤本哲男, 堀切芳一, 岩崎清隆, 曾我新吾

第15回ライフサポート学会大会講演予稿集 94 1999.10
新しい肺動脈弁の弁機能を目的とした右心系血液循環シミュレータの開発

第15回ライフサポート学会大会講演予稿集 92 1999.10
生体左心室のねじり収縮を模擬した左心室モデルの製作および評価

東野純大, 有田誠, 藤本哲男, 梅津光生

第15回ライフサポート学会大会講演予稿集 57 1999.10
Development of a Durable Polymer Valve Based on Finite Element Analysis

K.Iwasaki, M.Umezu, Y.Kobayashi, K.Imachi, T.Fujimoto

Proceedings of APCMB'99 252 1999.09
Prediction of In-vitro Hemolysis by Energy Dissipation for Laminar and Turbulent Flow

M.Umezu, K.Kohno, M.V.Kameneva, B.Repko, J.Antaki

Proceedings of APCMB'99 249 1999.09
人工血管置換前後の左心室ポンプ負荷の力学的変動

白石泰之, 石橋和幸, 有田誠, 藤本哲男, 梅津光生, 川副浩平

第37回日本人工臓器学会大会予稿集/日本人工臓器学会 28 ( 4 ) s-92 1999.09
高分子製人工弁の加速耐久試験法確立に向けての力学的検討

岩崎清隆, 梅津光生, 井街宏, 藤本哲男

第37回日本人工臓器学会大会予稿集/日本人工臓器学会 28 ( 4 ) s-78 1999.09
高速ビデオカメラを用いた人工弁の回転に関する検討

藤本哲男, 比留間信義, 堤祐一, 白石泰之, 梅津光生, John Begg

第37回日本人工臓器学会大会予稿集/日本人工臓器学会 28 ( 4 ) s-77 1999.09
冠動脈ステントの力学的挙動試験

梅津光生, 堀切芳一, 藤本哲男

第37回日本人工臓器学会大会予稿集/日本人工臓器学会 28 ( 4 ) s-12 1999.09
次世代型長期補助人工心臓:植え込み型遠心ポンプ“EVAHEART”

山崎健二, 秋本剛秀, 田鎖治, 富岡淳, 梅津光生, 太田英輔, 宮城島正行, 森敏夫, 小柳仁, Philip Litwak

第37回日本人工臓器学会大会予稿集/日本人工臓器学会 28 ( 4 ) s-5 1999.09
Preliminary study on the new self-closing mechanical mitral valve

K Naemura, M Umezu, T Dohi

ARTIFICIAL ORGANS 23 ( 9 ) 869 - 875 1999.09 [Refereed]

　View Summary

A natural mitral valve starts closing before systole. Conventional mechanical mitral valves start their closing motion after systole. In order to let the mechanical mitral valves start closing before systole, we propose a new self-closing Valve by adjusting the center of gravity of the leaflet. As a first step, we adjusted the center of gravity by attaching a block of lead to the leaflet of a CarboMedics bileaflet valve and evaluated it using a pulse duplicator and an x-ray high-speed video camera. Comparative study was conducted under 60 bpm and 4 L/min as the mean now rate. It was clarified that the self-dosing valve started closing before systole, no influence on inflow volume was found, the final closing speed of the self-closing valve just before complete closure was slower than the conventional valve (1.9-0.34 m/s), a design strategy of a self-closing valve (sewing ring diameter 29 mm) was obtained from the experiment that momentum of inertia of the leaflet should be less than 14.9 x 10(-9) kg.m(2) and the torque caused by gravity should be more than 4.2 x 10(-6) N . m, and only one leaflet should be designed as self-closing, and surgeons need to pay attention to the positioning of the two leaflets. In conclusion, the preliminary study showed the ability of starting to close before systole and the design strategy for future prototyping.
Rotary blood pump flow spontaneously increases during exercise under constant pump speed: Results of a chronic study

T Akimoto, K Yamazaki, P Litwak, KN Litwak, O Tagusari, T Mori, JF Antaki, MV Kameneva, MJ Watach, M Umezu, J Tomioka, RL Kormos, H Koyanagi, BP Griffith

ARTIFICIAL ORGANS 23 ( 8 ) 797 - 801 1999.08 [Refereed]

　View Summary

Many types of rotary blood pumps and pump control methods have recently been developed with the goal of clinical use. From experiments, we know that pump flow spontaneously increases during exercise without changing pump control parameters. The purpose of this study was to determine the hemodynamics associated with the long-term observation of calves implanted with centrifugal blood pumps (EVAHEART, Sun Medical Technology Research Corporation, Nagano, Japan). Two healthy female Jersey calves were implanted with devices in the left thoracic cavity. A total of 22 treadmill exercise tests were performed after the 50th postoperative day. During exercise, the following parameters were compared with conditions at rest: heart rate, blood pressure, central venous oxygen saturation (SvO(2)), pump speed, and pump flow. The pump flow in a cardiac cycle was analyzed by separating the systole and diastole. Compared to the base data, statistically significant differences were found in the following interrelated parameters: the heart rate (66.8 +/- 5.2 vs. 196 +/- 9.7 bpm), mean pump flow (4.8 +/- 0.2 vs. 7.0 +/- 0.3 L/min), and volume of pump now in diastole (26.9 +/- 1.8 vs. 13.5 +/- 2.5 ml). During exercise, the volume of pump flow in systole was 3 times larger than that measured in diastole. Blood pressure, SvO(2), and pump speed did not change significantly from rest to exercise. These results suggested that the mean pump flow depends on the systolic pump flow. Therefore, the increase in the mean pump flow during exercise under constant pump speed was caused by an increase in the heart rate.
In-vitro Performance Testing for Coronary Stents including Pulstatile Flow Study

M.Umezu, Y.Horikiri, K.Tannji, S.Soga, K.Aoyagi, T.Fujimoto

Artificial Organs/Blackwell Science,Inc. 23 ( 7 ) 686 1999.07
Effects of Cardiac Function on an Arterial Vascular Graft Implantation

Y.Shiraishi, M.Umezu,T.Fujimoto

Artificial Organs/Blackwell Science,Inc. 23 ( 7 ) 685 1999.07
Relationship between Rotation and Energy Loss in a Prosthetic Heart Valve under Spiral Flow Conditions

T.Fujimoto, M.Umezu, N.Hiruuma, Y.Tsutsumi, Y.Shiraishi, S.Mochizuki, J.Begg, J.Woodard

Artificial Organs/Blackwell Science,Inc. 23 ( 7 ) 666 - 666 1999.07

CiNii
循環シミュレータ

梅津光生

計測と制御/(社)計測自動制御学会 38 ( 5 ) 312 - 316 1999.05
Development of Artificial Left Ventricle Model Simulated to the Contraction form of the Natural Heart

M.Arita, M.Umezu, S.Tono, T.Fujimoto

Proceedings of Inaugural Japan-Australia Cardiovascular Bioengineering Meeting 43 - 44 1999.05
Mechanical Circulatory Simulator with Control Mechanisms

Y.Shiraishi, M.Umezu,I.Nazuka, Y.Kondo, T.Umezu

Proceedings of Inaugural Japan-Australia Cardiovascular Bioengineering Meeting 38 - 39 1999.05
A New Approch for the Improvement of Accelerated Fatigue Testing Methodology

K.Iwasaki, M.Umezu, Y.Kobayashi, T.Fujimoto, K.Imachi

Proceedings of Inaugural Japan-Australia Cardiovascular Bioengineering Meeting 29 - 30 1999.05
Effect of Spiral Flow on thePerformance of Prosthetic Heart Valves

T.Fujimoto, M.Umezu, N.Hiruma, Y.tsutsumi, Y.Shiraishi, J.Begg, J.Woodard

Proceedings of Inaugural Japan-Australia Cardiovascular Bioengineering Meeting 28 1999.05
Contribution of Mechanical Engineering to the Field of Artificial Organs

M.Umezu, T.Fujimoto, Y.Shiraishi, K.Iwasaki, K..Kohno, M.Arita

Proceedings of Inaugural Japan-Australia Cardiovascular Bioengineering Meeting 2 - 3 1999.05
In-vitro Laser Doppler Anemometry of Pulsatile Flow Velocity and Shear Stress Measurements Downstream from a Jellyfish Valve in the Mitral Position of a Ventricular Assist Device

Yos morsi, M.Umezu,M.Kogure

J.Artificial Organs/The Japanese Society for Artificial Organs 2 ( 2 ) 62 - 73 1999.04
Analysis of ATS Leaflet Behavior by In-vitro Exeriment

Zhonggang Feng, M.Umezu,T.Fujimoto, T.Tsukahara, M.Nurishi, D.Kawaguchi, M.Masuda

J.Artificial Organs/The Japanese Society for Artificial Organs 2 ( 2 ) 45 - 46 1999.04
早稲田大学理工学総合研究センター

梅津光生

人工臓器/日本人工臓器学会 28 ( 3 ) 633 - 634 1999
Relative blood damage index of the jellyfish valve and the Bjork-Shiley tilting-disk valve

Yos Morsi, Masahisa Kogure, Mitsuo Umezu

Journal of Artificial Organs 2 ( 2 ) 163 - 169 1999

　View Summary

Determination of the potential for blood cell damage induced by artificial heart valves is essential in deciding the suitability of the valve for clinical use. Both the magnitude and the duration of the shear stress influence the onset and severity of the damage to the constituents of blood. In this study, in vitro shear stress measurements of the mitral jellyfish and Bjork-Shiley tilting-disk (mono) prosthetic valves under physiological pulsatile flow conditions were conducted. The data indicate that elevated levels of shear stress occurred mainly ID downstream from both valves. With the aid of a mathematical model and using the elevated shear stress data, the relative release of hemoglobin by damaged red blood cells and of lactate dehydrogenase by platelets was computed for both valves. For the operating conditions examined, the jellyfish valve was found to cause the least damage to blood, with a relative blood damage index of 0.27 against a value of 0.47 for the Bjork-Shiley valve.

DOI

Scopus

15

Citation

(Scopus)
Basic performance of "Waseda mock circulatory system"

Umezu,M, Fujimoto,T, Shiraishi,Y, Arita,M, Tohno,S

49th Seminar of the International Center for Biocybernetics, "Heart and Lunf Assistance" 9 - 15 1998.11
Hydrodynamic performance of outlet valves in Australian-made spiral vortex pump

Umezu,M, Fujimoto,T, Tsutsumi,J.,J, Begg.,J, Woodard

49th Seminar of the International Center for Biocybernetics, "Heart and Lunf Assistance" 16 - 23 1998.11
Performance of prosthetic heart valves under spiral flow conditions

T.Fujimoto, Y.Ueda, N.Hiruma, M.Yoshida, M.Umezu, S.Mochizuki, JohnBegg.,John

The International Journal of Artificial Organs (ABSTRACTS of the XXVth ESAO Congress)-(Bologna) 21 ( 10 ) 646 1998.11
Energy dissipation as a primary factor to predict hemolisis under arbitrary conditions

K.Kono, V.Kameneva, M.Umezu, J.F.Antaki, B.Repko, K.K.Yeleswarapu

The International Journal of Artificial Organs (ABSTRACTS of the XXVth ESAO Congress-Bologna) 21 ( 10 ) 599 1998.11
医療用高分子材料の疲労が血液適合性に与える影響の基礎検討

岩﨑清隆, 井街宏, 松浦弘幸, 苅田達郎, 梅津光生, 小林洋平, 藤本哲男

第14回ライフサポート学会大会講演予稿集(大分) 106 1998.11
ロジスティック回帰分析におけるステップ・ワイズ法の再現性について

吉田正徳, 藤本哲男, 梅津光生

第14回ライフサポート学会大会講演予稿集(大分) 102 1998.11
真空形成型補助人工心臓の耐久性向上のための改良

中田紀彦, 比留間信義, 有田誠, 梅津光生, 藤本哲男

第14回ライフサポート学会大会講演予稿集(大分) 48 1998.11
ステントの力学的評価法の検討

堀切芳一, 梅津光生, 藤本哲男, 岩﨑清隆, 丹治一幸, 曽我新吾, 青柳健悟

第14回ライフサポート学会大会講演予稿集(大分) 32 1998.11
長期循環補助を目的とした体内植え込み型遠心ポンプの開発

山崎健二, 田鎖治, 秋本剛秀, 富岡淳, 梅津光生, 太田英輔, 川合明彦, Philip Litwak,Robert

人工臓器 27 ( 4 ) s-28 1998.09
耐久性向上を目指した高分子製人工心臓弁の設計改良と試作

岩﨑清隆, 梅津光生, 井街宏, 藤本哲男

人工臓器 27 ( 4 ) s-39 1998.09
旋回流における各種人工弁のエネルギー損失の比較

藤本哲男, 比留間信義, 白石泰之, 梅津光生, John Begg, John Woodard

人工臓器 27 ( 4 ) s-81 1998.09
循環器系人工臓器の血行動態、耐久性、血液適合性のinvitro評価システムの開発

梅津光生

人工臓器 27 ( 4 ) s-23 1998.09
Emax推定による補助循環の定量的評価

吉澤誠, 田中明, 阿部健一, 竹田宏, 柿沼義人, 秋保洋, 山家智之, 仁田進一, 梅津光生

人工臓器 27 ( 4 ) s-145 1998.09
心臓弁機能の流体力学的解析と術中応用の可能性

市場谷絵美, 井澤周作, 藤里俊哉, 辻隆之, 梅津光生, 大場謙吉

日本コンピュータ外科学会大会予稿集(東京) 121 - 122 1998.09
In vitro investigation on the mechanism of the leaflet movement of "ATS" open pivot bileaflet valve

G.Feng, Tsukahara,T, Nurishi,M, Kawaguchi,D, Fujimoto,T, Umezu,M

Proceedings of International Conference on Biomedical Engineering '98 (Tokyo) 7 - 8 1998.09
Prototyping of mechanical self-closing valve in mitral position

Naemura,K, Umezu,M, Dohi,T

Proceedings of International Conference on Biomedical Engineering '98 (Tokyo) 3 - 6 1998.09
Three types of in vitro evaluation test system for blood pump performance

Umezu,M, Fujimoto,T, Shiraishi,Y, Iwasaki,K, Zhonggang Feng

Proceedings of International Conference on Biomedical Engineering '98 (Tokyo) 1 - 2 1998.09
A new approach for development of a sophisticated mock circuratory system

Shiraisho,Y, Fujimoto,T, Arakawa,M, Yamasaki,K, Yamasaki,F, Hotta,Y, Umezu,M, Shizuka,K, Kobayashi,S, Yambe,T, Nitta,S

Abstracts of the Third World Congress of Biomechanics (Sapporo) 408 1998.08
Experimental investigation of fluid characteristics of Jellyfish valves using IDA

Kogere,M, Yos S Morsi, Umezu,M

Abstracts of the Third World Congress of Biomechanics (Sapporo) 359 1998.08
Evaluation of stenosis in artificial valves

Tsuji,T, Izawa,S, Nagahisa,H, Fujimoto,T, Miyawaki,F, Ohba,K, Umezu,M

Abstracts of the Third World Congress of Biomechanics (Sapporo) 358 1998.08
In vitro hydrodynamic comparison among three types of bileaflet valves

Abstracts of the Third World Congress of Biomechanics (Sapporo) 357 1998.08
Hydrodynamic characteristic of a bi-leaflet heart valve with a rotational disk movement

Nakada,N, Umezu,M, Iwasaki,K, Shiraishi,Y, Fujimoto,T, Kobayashi,H, Tanaka,H

Abstracts of the Third World Congress of Biomechanics (Sapporo) 357 1998.08
Quantitative evaluation of aortic regurgutation-analysis using poliurethane tricuspid aortic valve.

Nagahisa,D.,Izawa,S, Fujimoto,T, Tsuji,T, Umezu,M, Ohba,K

Abstracts of the Third World Congress of Biomechanics (Sapporo) 356 1998.08
Closing motion analysis for a newly designed mechanical mitral valve prosthesis.

Naemura,K, Umezu,M, Dohi,T

Abstracts of the Third World Congress of Biomechanics (Sapporo) 356 1998.08
In vitro evaluation of coronary stents

Iwasaki,K, Umezu,M, Soga,S, Ajiki,Y, Fujimoto,T, Horikiri,Y, Yokomatsu,M

Abstracts of the Third World Congress of Biomechanics (Sapporo) 340 1998.08
Mechanism of calcification on the Jellyfish valve and its protection

Imachi,K, Matsuura,H, Karita,T, Iwasaki,K, Chinzei,Y, Abe,Y, Mabuchi,K, Umezu,M

Abstracts of the Third World Congress of Biomechanics (Sapporo) 199 1998.08
A role of sorhisticated mock circulatory system to evaluate a function of artficual organs

M Umezu

Abstracts of the Third World Congress of Biomechanics (Sapporo) 197 1998.08
An implantable centrifugal blood pump with a recirculating purge system (Cool-Seal system)

K Yamazaki, P Litwak, O Tagusari, T Mori, K Kono, M Kameneva, M Watach, L Gordon, M Miyagishima, J Tomioka, M Umezu, E Outa, JF Antaki, RL Kormos, H Koyanagi, BP Griffith

ARTIFICIAL ORGANS 22 ( 6 ) 466 - 474 1998.06 [Refereed]

　View Summary

A compact centrifugal blood pump has been developed as an implantable left ventricular assist system. The impeller diameter is 40 mm, and pump dimensions are 55 x 64 mm. This first prototype, fabricated from titanium alloy, resulted in a pump weight of 400 g including a brushless DC motor. The weight of a second prototype pump was reduced to 280 g. The entire blood contacting surface is coated with diamond like carbon (DLC) to improve blood compatibility. Flow rates of over 7 L/min against 100 mm Hg pressure at 2,500 rpm with 9 MI total power consumption have been measured. A newly designed mechanical seal with a recirculating purge system (Cool-Seal) is used for the shaft seal. In this seal system, the seal temperature is kept under 40 degrees C to prevent heat denaturation of blood proteins. Purge fluid also cools the pump motor coil and journal bearing. Purge fluid is continuously purified and sterilized by an ultrafiltration unit which is incorporated in the paracorporeal drive console. In vitro experiments with bovine blood demonstrated an acceptably low hemolysis rate (normalized index of hemolysis = 0.005 +/- 0.002 g/100 L). In vivo experiments are currently ongoing using calves. Via left thoracotomy, left ventricular (LV) apex descending aorta bypass was performed utilizing an expanded polytetrafluoroethylene (ePTFE) vascular graft with the pump placed in the left thoracic cavity, In 2 in vivo experiments, the pump flow I-ate was maintained at 5-9 L/min. and pump power consumption remained stable at 9-10 W. AIL plasma free Hb levels were measured at less than 15 mg/dl. The seal system has demonstrated good seal capability with negligible purge fluid consumption (<0.5 ml/day). In both calves, the pumps demon strated trouble free continuous function over 6 month (200 days and 222 days).
In vitro evaluation of blood pump performance

M Umezu

Artificial Organs and Related Technologies/Japan Society of Promoting Science Polish Academy of Sciences (Tokyo) 1998.05
血液循環シュミレータ内でのウィクターステントの挙動

Wiktor Stent Synposium(Medtronic Inc.),(大阪) 1998.04
人間総合研究センターシンポジウム「医療に関わる技術の現状」を開催して

ヒューマンサイエンス/人間総合研究センター 10 ( 2 ) 4 - 5 1998.03
有限要素法を用いたひずみ解析によるJerry-fish弁のカルシウム沈着発生位置の検討

岩﨑清隆, 梅津光生, 藤本哲男, 井街宏

人工臓器/日本人工臓器学会 27 ( 2 ) 545 - 550 1998.03
真空成形による血液ポンプの内部コーティング法の検討

ライフサポート 10 ( 1 ) 19 - 24 1998.03
真空成形法による補助人工心臓の開発

マイクロ技術研究会活動報告 4, 1998.03
Application of rotational moulding for the development of artificial organs

Umezu M

Rotation (The Magazine of International Rotational Molding Industry) 7 ( 3 ) 24 - 31 1998.03
Basic study towards the establishment of a fabrication technology for a vacuum-formed blood pump

UMEZU M.

Heart Replacement - Artificial Hearet / Springer-Verlag 6 353 - 357 1998.02

CiNii
Improvement of an aortic region in a mock circulatory system verified from goat experiment

Shiraishi,Y, Fujimoto,T, Arakawa,M, Yamasaki,K, Yamasaki,Y, Hotta,Y, Umazu,M, Shizuka,K, Kobayashi,S, Yambe,T.Nitta,S

9th International Conference on Biomedical Engineering 363 - 365 1997.12
Improvement of dynamic conditions in the acclelerated fatigue testing for prosthetic heart valve

Iwasaki,K, Umezu,M, Wakui,H, Kawada,H, Fujimoto,T, Imachi,K

9th International Conference on Biomedical Engineering 342 - 344 1997.12
The effect of leaflet thickness on the valve dynamics of a polyurethane trileaflet heart valve

Heejung K wescoat, Iinuma,K, S H Teoh, Y T Chew, Umezu,M

9th International Conference on Biomedical Engineering 339 - 341 1997.12
Establishment of an internal coating method of blood pumps with non-thrombogenic polymer

NURISHI M.

9th International Conference on Biomedical Engineering 286 - 288 1997.12

CiNii
Hydrodynamic analysis of rotary blood pumps using computational fluid dynamics

9th International Conference on Biomedical Engineering 277 - 279 1997.12
Development of a mechanical circulatory simulator to evaluate hemodynamics of artificial organs

M Umezu

9th International Conference on Biomedical Engineering 153 - 155 1997.12

CiNii
Physiologic remodeling annuloplasty to retain the shape of the anterior leaflet: A new concept in mitral valve repair

H Kasegawa, S Kamata, T Ida, M Kawase, T Fujimoto, M Umezu

JOURNAL OF HEART VALVE DISEASE 6 ( 6 ) 604 - 607 1997.11 [Refereed]

　View Summary

Background and aims of the study: The Carpentier-Edwards (CE) ring was developed to restore the normal 3:4 ratio between the anteroposterior and transverse diameters of the mitral valve orifice during systole. It is difficult to use in patients in whom the ratio is more than 3:4. To overcome this problem, we developed an adjustable obturator, the ratio of which may be changed by sliding apart its two components.
Methods: Remodeling annuloplasty was performed using part of a flexible Duran ring or autologous pericardium and the adjustable obturator in 17 patients with severe MR, including two with high anterior leaflet.
Results: Physiologic remodeling annuloplasty was easily accomplished in all cases. Intraoperative echocardiography was performed in 14 patients, and it showed no regurgitant jet in 11 cases and only trivial jet in three.
Conclusion: Physiologic remodeling annuloplasty to retain the natural shape of the anterior leaflet by using an adjustable obturator is a very useful technique that enables annuloplasty to be performed in all cases, irrespective of the shape of the anterior leaflet.
Three-dimentional rotational moulding machine for manufacturing artificial organs(人工臓器製作用三次元回転成形機)

Umezu,M, Teoh Swee-Hin

医用電子と生体工学/日本ME学会第35巻秋季特別号 55 1997.11
Long term animal experiments with an international axial flow blood pump

Yamazaki,K, Robert L Kormos, Philip Litwak, Tagusari,O, Mori,T, James F Antaki

ASAIO Journal 43 ( 5 ) 696 - 700 1997.10
Implantable centrifugal blood pump for long term circulatory support

Yamazaki,K, Philip Litwak, Robert L Kormos, Mori,T, Tagusari,O, James F Antaki

ASAIO Journal 43 ( 5 ) 686 - 691 1997.10
Comparison of the closing dynamics of mechanical prosthetic heart valve

Naemura,K, Ohta,Y, Fujimoto,T, Umezu,M, Matsumoto,H, Dohi,T

ASAIO Journal 43 ( 5 ) 401 - 403 1997.10
In-vitro assessment of a polyurethane trileaflet heart valve

第35回日本人工臓器学会大会予稿集 26 supliment ,p. 1997.10
新しい僧帽弁輪形成術のためのadjustable obtulator の開発

第35回日本人工臓器学会大会予稿集 26 supliment ,p. 1997.10
人工弁を用いた弁閉鎖不全解析とその温度による影響

第35回日本人工臓器学会大会予稿集 26 supliment ,p. 1997.10
X線高速ビデオカメラによる機械式心臓代用弁の閉鎖運動解析

第35回日本人工臓器学会大会予稿集 26 supliment ,p. 1997.10
機械式人工弁における開放特性のディスク形状による比較検討

第35回日本人工臓器学会大会予稿集 26 supliment ,p. 1997.10
Totally implantable centrifugal blood pump for long-term circulatory support

第35回日本人工臓器学会大会予稿集 26 supliment ,p. 1997.10
人工臓器の臨床試験に対する国際化の波

人工臓器/日本人工臓器学会 26 ( 5 ) 903 1997.10
A new national project for comprehensive basic reserch on the development of Japanese original implantable total artificial heart

Imachi,K, Kamiya,A, itta,S, Mitamura,Y, Umezu,M, Matsuda,T

Artificial Organs 20 ( 9 ) 498 1997.09
Estimation of drag and lift coefficients of monoleaflet tilting disk during opening phase using a high speed video camera

Fujimoto,T, Maki,Y, Shiraishi,Y, Yoshida,M, Umezu,M, Naemura,K, Akutsu,T, Mochizuki,M

Artificial Organs 20 ( 9 ) 516 1997.09
Quantitative evaluation of regurgitation in polyurethane tricuspid aortic valve

Nagahisa,D, Fujisato,T, Tsuji,T, Umezu,M, Ohba,K

The Third Far-Eastern Symposium on Biomedical Materials Abstract 84 1997.07
「これからの人間に関わる技術-医療・福祉、安全・防災-」特集号発刊に際して-人工臓器研究を通じて実感したこと-

梅津光生

日本機械学会誌 100 ( 944 ) 1 - 3 1997.07
ポリウレタン製人工弁閉鎖不全の温度変化による影響

長久大地, 藤里俊哉, 辻隆之, 梅津光生, 大場謙吉

第20回日本バイオレオロジー学会年会抄録集 46 1997.06
ポリウレタン製人工弁閉鎖不全の解析

長久大地, 井内康浩, 藤里俊哉, 辻隆之, 梅津光生, 大場謙吉

医用電子と生体工学/日本ME学会第35巻特別号 467 1997.04
人工心臓内部血液接触面のコーティング

第16回マイクロ技術研究講演会 1997.03
「ヘルス・フィットネスサポート」プロジェクト研究の10年間の歩み

永田晟, 梅津光生

ヒューマンサイエンス/人間総合研究センター 10 ( 1 ) 58 - 64 1997.02
未来の医療機器の性能評価方法の確立にむかって

BME 12 ( 1 ) 39 - 47 1997.02
ポリウレタン製人工弁閉鎖不全の解析

第9回バイオエンジニアリング講演会講演論文集 111 - 113 1997.01
Study of the effect of atrial contraction on mitral prosthetic valve by high speed video camera

K. Naemura, M. Sonderegger, H. Matsumoto, T. Dohi, K. Izumi, T. Fujimoto, M. Umezu, Y. Ota

Artificial Organs 21 ( 4 ) 300 - 305 1997

　View Summary

To clarify the effect of atrial contraction on the dynamic behavior of mitral prosthetic valves, a mechanical mock circulatory system has been developed. It is able to simulate the inflow characteristics during diastole. The disc motions of Bjork-Shiley Monostrut (BSM29) and CarboMedics (CM29) valves (both with an annulus diameter of 29 mm) were measured and compared with a high speed video camera. After contraction of the artificial atrium (100 ms), there was a delay of 75 ms before the onset of the ventricular contraction. Mitral flow similar to physiological conditions could be achieved. The BSM29 was tested in the anterior-position (a) and the posterior position (p). Under the condition of active atrial contraction (AC), we confirmed that the closing motion was initiated and the period during closing motion (PDCM) was prolonged (BSM29[a]: 22.4 ± 3.4 → 63 ± 3.2
BSM29[p]: 71.2 ± 38 → 94.2 ± 11
and CM29: 14 ± 0.0 → 28.4 ± 2.3 [unit: ms]), the prolongation of the PDCM of the CM29 due to the AC being smaller than that of the BSM29. We also confirmed that the closing volume (CV) increased slightly (BSM29 [a]: 7.8 ± 0.4 → 8.5 ± 0.8
BSM29[p]: 6.9 ± 0.6 → 7.0 ± 0.5
and CM29: 3.6 ± 0.6 → 4.1 ± 0.6 [unit: ml]). The CM29 had a shorter PDCM, less prolongation of the PDCM due to the AC, and less CV than the BSM29. Thus, we confirmed that the CM29 produced better response at valve closure than the BSM29.

PubMed
早稲田大学人間総合研究センター「ヘルスフィットネスサポート」プロジェクト研究の現状-特集にあたって

ヒューマンサイエンス/早稲田大学人間総合研究センター 9;1 1996.11
Polymer valves for artificial heart using a rotational moulding machine

Abst. of Polymer processing towards AD 2000 1996.11
Vacuum formed ventricular assist device: effects of material design and fabrication on pump performance

Abst. of Polymer processing towards AD 2000 1996.11
単純運動に対する末梢循環応答特性-皮膚温度と皮膚血流決定のための数式モデルの作製

ヒューマンサイエンス/早稲田大学人間総合研究センター 9 ( 1 ) 1996.11
運動負荷による僧帽弁位心臓代用弁の機能評価に対する工学的考察

ヒューマンサイエンス/早稲田大学人間総合研究センター 9 ( 1 ) 1996.11
血圧調節機構を有する血液循環系シミュレーションモデルの開発(第2報)運動負荷の機械式モデルにおける再現

ヒューマンサイエンス/早稲田大学人間総合研究センター 9 ( 1 ) 1996.11
血圧調節機構を有する血液循環系シミュレーションモデルの開発(第1報)血圧調節系のアルゴリズムの開発

ヒューマンサイエンス/早稲田大学人間総合研究センター 9 ( 1 ) 1996.11
心臓代用弁の現況

BME 10;10 1996.10
X線シネ撮影より高速度な人工弁運動の計測

第34回日本人工臓器学会大会予稿集/人工臓器学会 1996.10
傾斜型単葉ディスク弁の開放特性に関する基礎的検討

第34回日本人工臓器学会大会予稿集/人工臓器学会 1996.10
X-ray high speed video camera for measurement of the motion of the implanted mechanical heart valve prostheses

Int.J.Artificial Organs/ European Society for Artificial Organs 19;9 1996.10
A study on the opening action of a monoleaflet tilting disc valve

Int.J.Artificial Organs/ European Society for Artificial Organs 19;9 1996.10
機械式心臓代用弁の開放特性の検討

日本機械学会第74期全国大会講演論文集/日本機械学会 1996.09
Hemocompatibility improvement of axial flow blood pump

Proceedings of Waseda International Congress of Modeling and Simulation Technology for Artificial Organs 1996.08
The effects of testing fluids on hydrodynamic characteristics of ventricular assist device

Proceedings of Waseda International Congress of Modeling and Simulation Technology for Artificial Organs 1996.08
Hydrodynamic evaluation of different sized prosthetic heart valves

Proceedings of Waseda International Congress of Modeling and Simulation Technology for Artificial Organs 1996.08
Interactions of the functions between artificial aortic valves and left ventricular pump obtained from a mock circulatory system

Proceedings of Waseda International Congress of Modeling and Simulation Technology for Artificial Organs 1996.08
Basic hydrodynamic study to establish a fatigue testing method for artificial valves

Proceedings of Waseda International Congress of Modeling and Simulation Technology for Artificial Organs 1996.08
Trials and evaluation study on a fabrication of elastic elements for artificial organs using a rotational molding machine

Proceedings of Waseda International Congress of Modeling and Simulation Technology for Artificial Organs 1996.08
Measurement of the prosthetic valve motion by X-ray high speed video camera

Proceedings of Waseda International Congress of Modeling and Simulation Technology for Artificial Organs 1996.08
In vitro flow dynamics of Jellyfish mitral prosthesis

Proceedings of Waseda International Congress of Modeling and Simulation Technology for Artificial Organs 1996.08
In-vivo evaluation of an intraventricular axial flow blood pump (IVAP)

The 6th international symposium on Artificial Heart & Assist Device 1996.07
Basic study towards an establishment of a fabrication technology for vacuum-formed blood pump

The 6th international symposium on Artificial Heart & Assist Device 1996.07
Effects of Surface Roughness on Mechanical Hemolysis

Artificial Organs/The International Society for Artificial Organs 20;6 1996.06 [Refereed]
医工学研究の立場から見た医療現場の展望

人間総合研究センターシンポジウム「医療にかかわる技術の現状」/早稲田大学人間総合研究センター 1996.06
Basic Performance of a Miniature Intraventricular Axial Pump

Artificial Organs/The International Society for Artificial Organs 20 ( 6 ) 1996.06 [Refereed]
Fluid dynamic investigation of mechanical blood hemolysis

Heart Replacement - Artificial Heart/Springer-Verlag 5 1996.05
心房収縮が人工弁動特性に与える影響の高速ビデオカメラによる検討

第35回日本ME学会大会講演論文集/日本ME学会 1996.05
血液循環シミュレータによる心臓ポンプ負荷と人工弁機能の関係の検討

日本機械学会第7回バイオエンジニアリング学術講演会・夏季セミナー講演論文集/日本機械学会 1996.04
高速ビデオカメラによる機械式心臓代用弁閉鎖特性の評価

日本機械学会第73期通常総会講演会講演論文集/日本機械学会 1996.04
回転型成形機による人工心臓部品の製作—ポリウレタン弁製作の試み

第24回人工心臓と補助循環懇話会抄録集 1996.02
真空成形法による補助心臓用人工弁の製作と改良

人工臓器/日本人工臓器学会 25;1 1996.02
人工臓器の試験を目的とした循環系モデルにおける動脈系の再現性(第2報)—脈波伝播特性を中心とした生体との比較

人工臓器/日本人工臓器学会 25;1 1996.02
Hemodynamic and Hydrodynamic study on the application of Spiral-Vortex Pump for an arterial pump in an extracorporeal circulation

第11回ライフサポート学会大会抄録集/ライフサポート学会 1995.11
補助人工心臓の耐久性評価法の検討

第11回ライフサポート学会大会抄録集/ライフサポート学会 1995.11
X線高速ビデオカメラによる人工弁動特性の計測

第11回ライフサポート学会大会抄録集/ライフサポート学会 1995.11
心臓代用弁の加速耐久試験法確立のための力学的検討

第11回ライフサポート学会大会抄録集/ライフサポート学会 1995.11
体循環シミュレータに用いる末梢抵抗器の開発と特性

第11回ライフサポート学会大会抄録集/ライフサポート学会 1995.11
Bio-mechanical engineering approaches for the improvement of blood pump design

人工臓器/日本人工臓器学会 24 (Suppl.) 1995.11
真空成形法による補助心臓用人工弁の製作と改良

人工臓器/日本人工臓器学会 24 (Suppl.) 1995.11
心房収縮が僧帽弁位人工弁の閉鎖挙動に与える影響の工学的検討

人工臓器/日本人工臓器学会 24 (Suppl.) 1995.11
人工臓器の試験を目的とした循環系モデルにおける動脈系の再現性(第2報)—脈波伝播特性を中心とした生体との比較

人工臓器/日本人工臓器学会 24 (Suppl.) 1995.11
Study on the effect of atrial contraction on mitral prosthetic valve by high speed video camera

Artificial Organs/International Society for Artificial Organs 19;10 1995.11
Dynamic characteristics of a silastic aorta in a mechanical circulatory system

Artificial Organs/International Society for Artificial Organs 19;10 1995.11
心房収縮が僧帽弁位人工弁の閉鎖挙動に与える影響の工学的検討

苗村潔, 土肥健純, 泉佳友子, 藤本哲男, 梅津光生, 北村昌也, 小柳仁, 太田裕治

人工臓器/日本人工臓器学会 24 (Suppl.) ( 4 ) 865 - 871 1995.11
How to deal with a peripheral resistance in a mock circulatory system ?

医用電子と生体工学/日本ME学会 33 (Suppl.) 1995.10
Development of an artificial peripheral resistance in a mechanical circulatory system

The International Journal Artificial Organs/European Society for Artificial Organs 18;8 1995.10
Development of a circulatory system to evaluate dynamic performance of prosthetic heart valves using a high speed video camera

The International Journal Artificial Organs/European Society for Artificial Organs 18;8 1995.10
シリコン製動脈硬化モデルに関する基礎的検討

日本機械学会第73期全国大会講演論文集(IV)/日本機械学会 95-10 1995.09
Particle tracking flow visualization within an intra-ventricular axial flow assist device

The 3rd Congress of The International Society for Rotary Blood Pumps, Houston, Texas, USA/International Society for Rotary Blood Pumps 1995.08
血液循環シミュレータの開発-エイジングを考慮した設計

ヒューマンサイエンス/人間総合研究センタ- 8-1 1995.08
バイオメディカルエンジニアリング-人工臓器

日本機械学会誌/日本機械学会 98-921 1995.08
Particle tracking flow visualization within an intra-ventricular axial flow assist device

The 3rd Congress of The International Society for Rotary Blood Pumps, Houston, Texas, USA/International Society for Rotary Blood Pumps 1995.08 [Refereed]
Effects of surface roughness on mechanical hemolysis

The 3rd Congress of The International Society for Rotary Blood Pumps, Houston, Texas, USA/International Society for Rotary Blood Pumps 1995.08
Intraventricular axial flow blood pump integrated with a purged seal system

The 3rd Congress of The International Society for Rotary Blood Pumps, Houston, Texas, USA/International Society for Rotary Blood Pumps 1995.08
Mechanism of Hemolysis Generated in Stenotic Connectors and FEM Analysis

日本機械学会第4回バイオエンジニアリングシンポジウム講演論文集/日本機械学会 95-26 1995.07
体循環シミュレータ用末梢抵抗器の開発と基礎特性

日本機械学会第4回バイオエンジニアリングシンポジウム講演論文集/日本機械学会 95-26 1995.07
高速ビデオカメラによる人工弁動特性解析用シミュレーションモデルの試作

日本機械学会第4回バイオエンジニアリングシンポジウム講演論文集/日本機械学会 95-26 1995.07
左心室流入期の機械式シミュレーションモデルを用いた僧帽弁位人工弁の動特性評価

医用電子と生体工学/日本ME学会 33 (Suppl.) 1995.05
高速ビデオカメラを用いた僧帽弁位における心臓代用弁の動特性解析

日本機械学会第72期通常総会講演会講演論文集 (I)/日本機械学会 95-1 1995.04
狭窄管における表面あらさの血球破壊(溶血)への影響

日本機械学会第72期通常総会講演会講演論文集 (I)/日本機械学会 95-1 1995.04
シリコン製大動脈モデルにおける脈波伝播特性

日本機械学会第72期通常総会講演会講演論文集 (I)/日本機械学会 95-1 1995.04
人工弁動特性解析を目的とした心房心室流入期モデルの開発

人工臓器/日本人工臓器学会 24;2 1995.04
生体に対する空圧駆動システムの優越性

油空圧技術/日本工業出版 35-1 1995.01
血液ポンプ

超精密生産技術体系/フジ・テクノシステム 4 1995.01
左心室形成術における切除線決定のための診断法の開発

植松美幸, 白石泰之, 関根一光, 山家智之, 西條芳文, 安藤隼人, 朴栄光, 武田朴, 岩﨑清隆, 梅津光生

生体医工学シンポジウムベストリサーチアワード,2005,9月
複数台の光学式三次元一計測装置を用いた手術ナビゲーションシステムの開発

原美紀子, 鈴川浩一, 植松美幸, 安藤隼人, 中村亮一, 伊関洋, 上杉繁, 梅津光生

第15回日本コンピュータ外科学会大会・第16回コンピュータ支援画像診断学会大会合同論文集 225 - 226
A newly-designed myocardinal assist device using a sophisticated shape memory alloy fibre

Yasuyuki SHIRAISHI, Tomoyuki YAMBE, Kazumitsu SEKINE, Daisuke OGAWA, Jun NAGATOSHI, Shinji ITO, Youngkwang PARK, Miyuki UEMATSU, Ryo SAKATA, Yumoko WADA, Yoshihumi SAIJO, Masaru HIGA, Yoshio HORI, Hongjian LIU, Qingtian WANG, Satoshi KONNO, Takashi KUWAYAMA, Paul OREGARIO, Akira TANAKA

Biocybernetics and Biomedical Engineering, Polish Academy of Sciences Institute of Biocybernetics and Biomedical Engineering 27 ( 1/2 ) 147 - 154
個々の赤血球の細胞内ヘモグロビン総量を画像計測する方法に関する基礎検討

関裕子, 八木高伸, 木田大輔, 岩本理沙, 梅津光生

第24回バイオエンジニアリング講演会講演論文集 8F26
ヒト冠動脈左前下行枝の運動

山本匡, 岩崎清隆, 岸上翔, 新井淳, 大場貴文, 挽地裕, 梅津光生

第25回バイオエンジニアリング講演会講演論文集 281 - 282
A proposal for redesigning aortofemoral prosthetic Y graft for treating abdominal aortic aneurysms

Tetsuo Fujimoto, Hiroshi Iwamura, Yasuyuki Shiraishi, Tomoyuki Yambe, Kiyotaka Iwasaki, Mitsuo Umezu

INTECH

▼display all

Books and Other Publications

人工臓器で幸せですか?

梅津光生

コロナ社 2005.10

Presentations

Our trial on biomedical engineering research and education system related to medical regulatory science,

7th WACBE World Congress on Bioengineering

Presentation date： 2015.07
My 40 years journey for a development of artificial hearts and clinical application,

ASCC 2015 10th Asian Control Conference

Presentation date： 2015.06
CFDが開く血流解析の新時代第，

30回日本脳神経血管内治療学会ランチョンセミナー講演

Presentation date： 2015.03
東京女子医科大学・早稲田大学連携先端生命医科学研究施設（TWIns）の取り組みについて

医工連携シンポジウムinあきた2015，

Presentation date： 2015.02
循環器系DRYラボセンターを駆使した治療リスクの低減システム構築と人材育成，

平成26年度厚生労働科学研究事業研究成果発表会，

Presentation date： 2015.02
理工学が先進医療に挑戦する，

（理数フロンティア研究指定校講演）

Presentation date： 2014.11
先進理工への挑戦—理工と医療の連携をどう進めるか，

特定非営利法人（NPO法人）シンクタンク発足記念学術講演会，

Presentation date： 2014.11
理工学の立場からの医工学人材の育成

日本臨床麻酔学会第34回大会

Presentation date： 2014.11
女子医大・早大の医療レギュラトリーサイエンスの共同大学院を運営して

，第8回医療機器に関するレギュラトリーサイエンス研究会（ＲＳ研究会）

Presentation date： 2014.09
Our new way to collaborate-another EBM;Engineering Based Medicine,,

2014 International Conference on Life System Modeling and Simulation and 2014 International Conference on intelligent Computing for Sustainable Energy and Environment

Presentation date： 2014.09
バイオエンジニアと血管外科医の真のコラボレーションの進め方

，第42回日本血管外科学会学術総会教育講演

Presentation date： 2014.05
最先端の教育研究環境，

第4回豊橋ライブデモンストレーションコース，2014．5（豊橋）

Presentation date： 2014.05
医学と工学：臨床医学を見据えた連携の実践と人材育成，

BIOMEDeviceセミナー，MedTech World主催，（文京シビックセンター）

Presentation date： 2014.04
先進医療への理工学からの挑戦

未来発見フォーラム，河合塾主宰

Presentation date： 2013.10
NORMO弁用心膜打ち抜き機の試作

第2回ステントレス僧帽弁臨床研究会，シンポジウム４，2013.7（神戸）

Presentation date： 2013.07
生体外における動静脈閉鎖系心筋組織構築，，2012.11（ポスター）

バイオマテリアル若手研究会

Presentation date： 2012.11
三次元心筋組織の構築に向けた足場材料の検討

バイオマテリアル若手研究会

Presentation date： 2012.11
医療機器開発の課題と今後の展望—真の医工連携の実現にむけて

第３回関西医療機器開発・製造展

Presentation date： 2012.10
日本発のイノベーションをどう展開するか

第1回ステントレス僧帽弁臨床研究会学術集会，シンポジウムⅠ

Presentation date： 2012.07
医工学連携の成果と展望

第1回ステントレス僧帽弁臨床研究会学術集会，ランチョンセミナー

Presentation date： 2012.07
真の医工連携−ものつくりの立場から−

日本組成加工学会東京・南巻頭支部技術サロンでの講演

Presentation date： 2012.07
血流可視化に基づく心臓手術の評価と計画

第1回研究交流フォーラム

Presentation date： 2012.03
レギュラトリーサイエンスから見た弁膜症治療の医工学的評価

日本医工学治療学会第28回学術大会

Presentation date： 2012.03
微小流路付きコラーゲンゲル培養における血管網導入三次元心筋組織の構築

第33回日本バイオマテリアル学会大会

Presentation date： 2011.11
Influences of gamma sterilization on mechanical properties and thermalstability of decellularized bovine pericardium: comparison between freeze-dried and hydrated tissues

Tissue Engineering and Regenerative Mdicine International Scociety Asia-Pacific Chapter Meeting

Presentation date： 2011.08
Investigation of mechanical and biochemical properties of freeze-dried and gamma sterilized porcine aorta

Tissue Engineering and Regenerative Mdicine International Scociety Asia-Pacific Chapter Meeting

Presentation date： 2011.08
Influence of sterilizationon durability of decellularized bovine extensor tendon

Tissue Engineering and Regenerative Mdicine International Scociety Asia-Pacific Chapter Meeting

Presentation date： 2011.08
Engineered vascularized cardiac tissue in a bioreactor

Tissue Engineering and Regenerative Mdicine International Scociety Asia-Pacific Chapter Meeting

Presentation date： 2011.08
A novel in-vitro immune-response screening system: Assessment of human blood response to decellularized, freeze-dried, and sterilized xenogeneic tissues

Tissue Engineering and Regenerative Mdicine International Scociety Asia-Pacific Chapter Meeting

Presentation date： 2011.08
Design philosophy of artificial heart with a consideration of sophisticated human control system

WSK-TNg Summer School 2010-The Emotional human robot interaction-(Seoul,Kprea)

Presentation date： 2010.10
シミュレータ実験、可視化実験、数値解析を駆使した先進医療への挑戦

第２０回北陸ＭＭＣ研究会

Presentation date： 2010.10
融合研究推進の環境作りの試み女子医大・早大連携施設（TWIns:ツインズ）の運営経験から

第11回山形ニューロサイエンス研究会

Presentation date： 2010.06
日本の技術を、いのちのために

第3回NPO健康医療開発機構シンポジウム報告

Presentation date： 2010.02
人工臓器最前線−早稲田の医療への挑戦−

早稲田大学エクステンション講演会、早稲田大学校友会和歌山県支部

Presentation date： 2009.03
オリジナル賞候補講演司会

第46回日本人工臓器学会大会

Presentation date： 2008.11
ＴＷＩnsの紹介と運営

TechnoFair WASEDA

Presentation date： 2008.10
機械工学からの医工連携分野への挑戦

TechnoFair WASEDA

Presentation date： 2008.10
Lecture “Introductioinof “Real Integrationamong Engineering,Science andMedicine:Introduction of New Research Joint Institute--TWIns””,Waseda-Scuola Superiore Sant’Anna-KIST International summer school “WSK2008” “Fundamentals of biorobotics

WSK2008

Presentation date： 2008.09
魅力ある論文の書き方−日本体外循環技術学会会員への期待−

第３４回日本体外循環技術医学会九州地方会(JaSECT KYUSHU)

Presentation date： 2008.06

▼display all

Research Projects

Development of the small blood circulation simulator to deepen the non-clinical evaluation of medical devices

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2018.04

-

2021.03

Umezu Mitsuo

　View Summary

As a final model of the blood circulatory simulator developed by the principal investigator (Prof Umezu) experienced for over 45 years, our team members have developed a 1/6 scale "ultra-small blood circulatory simulator". Fresh human blood was injected into the circuit, and a flow diverter, which is a new medical device aimed at preventing the rupture of a cerebral aneurysm, was placed into this mini-circuit. The relationship between pressure and flow rate in the simulator is very similar to that of human hemodynamics, and the results of imaging with an ultrasonic diagnostic device revealed the thrombus formation process. From the above, it was confirmed that our newly-developed ultra-small blood circulatory simulator can be regarded as a useful tool to determine effective treatment guidelines for the patients.
Safety and Effectiveness of Stentless Mitral Valve for Mitral Stenosis

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2017.04

-

2021.03

Yaku Hitoshi

　View Summary

Stentless mitral valve was developed for compensating the shortcomings of bioprosthetic and mechanical valves. Ii is expected that stentless mitral valve may have longer durability than bioprosthetic valve without using warfarin. This time, we have evaluated long term results of 18 implanted stentless mitral valves in three institutions in Japan. There was no operative mortality cases. However, during follow up period (mean 4.5 years), 8 patients required redo mitral valve replacement. Freedom from more than moderate mitral regurgitation was 42% after 8years. From these results, there were cases which long term durability was less than expected.
Construction of ventricular tissue from human iPS cell-derived cardiomyocytes on vECM-nanographene composite substrate

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2017.04

-

2020.03

Feng Zhonggang

　View Summary

In this study, we pursued the strategy of integrating the cardiomyocyte differentiation, selection, and tissue construction into a continuous in-vivo simulation process. To this end, a vECM+nGraphene culture substrate was developed, which was based on ventricular extracellular matrix hydrogel and patterned stretchable nanographene electrodes were embedded in. The biochemical, biomechanical, and electrical properties of the substrate can be adjusted by means of crosslinker, concentration change. and application of strain and electrical stimuli. Cardiomyocyte differentiation was conducted on the substrate, and ventricular tissue was engineered by stacking intermediate modules, which were the construction blocks developed by the above strategy. It was confirmed that the hierarchical structure can be formed based on the substrate. The enhancement of the specific genetic expression and cellular orientation were also implicated.
Development of mock circulation systems for the evaluation of innovative medical devices

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2015.04

-

2018.03

UMEZU Mitsuo

　View Summary

The purpose of this study is to develop mock circulation systems for the evaluation of innovative medical devices, which are artificial heart valve, transcatheter aortic valve, and bioresorbable vascular scaffold.The results of this study will contribute to estimate factors of adverse events and support the planning solutions for the events that are difficult to analyze in the real world
Elucidation of blood flow control mechanisms for establishing a wide area of simulator of brain circulation after cerebral revascularization

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2015.04

-

2018.03

Hiroharu Kataoka

　View Summary

Cerebral revascularization is an established surgical treatment for intracranial aneurysm and ischemic cerebrovascular disease. However, one problem of this treatment is that we cannot predict the postoperative hemodynamics. In this study, we have integrated the measurement of blood flow in intracranial arteries by phase contrast MRI, measurement of cereral blood flow by PET/SEPCT and computationla fluid dynamics (CFD), and have clarified a part of mechanisms of local vascular adjustment and redistribution of cerebral blood flow after revascularization surgery. Results of this study will lead to the development of a simulator for cerebral blood flow in the whole brain area which predicts postoperative hemodynamics, and will contribute to the improvement of treatment results after revascularization surgery
Development of a tissue with in vivo regeneration capability for reconstruction of anterior cruciate ligament using decellularization and tissue-sterilization technologies

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2014.04

-

2017.03

Iwasaki Kiyotaka

　View Summary

In the treatment of knee anterior cruciate ligament (ACL) ruptured in sports and so on, patient’s own tendon is harvested and used. In this study, as a new tissue substitute, porcine tendon was used, and decellularization and sterilization technologies of tissues were established. Experiments of reconstruction of ovine knee ACL using decellularized and sterilized porcine tendons revealed that the decellularized tissues were functioned 3 months. The tissues were repopulated in vivo with ovine autologous cells and vessels were formed. Ultimate tensile loads after 3 months implantation were comparable between decellularized porcine tissues and autologous Achilles tendons. This study opened a new way to develop a novel medical device to treat ACL without need of harvesting patient’s own tendon
新規治療機器を実臨床に導入時に有効な循環シミュレータの開発

科学研究費助成事業(早稲田大学) 科学研究費助成事業(基盤研究(B))

Project Year :

2015

-

2017
Cardiac tissue engineering through the creation of a novel culture substrate promoting cardiomyocytes differentiation and selection

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2013.04

-

2016.03

Feng Zhonggang, NAKAMURA Takao, KOSAWADA Tadashi, UMEZU Mitsuo

　View Summary

This research aims to develop a novel approach for cardiac tissue engineering through the creation of the culture substrate which promotes the cardiac differentiation of ES/iPS cells and the selection of the differentiated target cells cultured on its surface. The culture substrate, a biohydrogel, was made from decellularized animal ventricular extracellular matrix. The research showed that stem cell differentiation can be modulated by controlling the mechanical properties of the culture substrate, and the target cell selection can be realized by imposing dynamic stress on the substrate. Bioreactor with mechanical stress control was developed to create the intermediate module for the cardiac tissue construction. This research presents a promising approach to tissue-engineer the highly functional cardiac tissue equivalent
Study on how to apply a simulation technique to evaluate a development of new medical devices and a possibility of their market approval

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2013.04

-

2015.03

NAKAOKA Ryusuke, UEMATSU Miyuki, UMEZU Mitsuo

　View Summary

A stent graft is a medical device for an endovascular treatment to prevent rupture of the aortic aneurysm. A fenestration type of the graft is utilized for preserving blood flow of arch and trifurcation vessels with the aneurysm. Medical doctors could predict the angle of graft rotation within an aorta under the pulsatile situation based on over 100 cases of clinical experience. Therefore, they know how to deploy a stent graft appropriately. However, it is difficult to feed others good tips on the stent graft deployment. The purpose of this study is to provide evidences with a mock system to promote awareness in clinical practice. We have developed a test method under pulsatile situation for evaluating aortic stent grafts
Development of a supporting technology for bypass surgery for complex intracranial aneurysms using a blood flow simulator

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2012.04

-

2015.03

KATAOKA HIROHARU, YAGI Takanobu, NAKAMURA Masanori, SAITO Kozue, UMEZU Mitsuo, IIHARA Koji

　View Summary

This study aimed at the prediction of cerebral hemodynamics after revascularization surgery for complex intracranial aneurysms by using phase contrast magnetic resonance imaging (PC-MRI) and computational fluid dynamics (CFD), thus developing a treatment support tool leading to the improvement of operative outcomes. First, we optimezed acquisition parameters of PC-MRI using a silicone model and normal volunteers, and then measured pre and post-operative blood flow in cerebral arteies of patients with an intracranial aneurysm undergoing a revascularzation surgery using optimezed parameters. Blood flow, vessel diameters and wall shear stress (WSS)dynamically changed immediate after surgery, and WSS tended to retrun to the preoperative value after three months. These results revealed one of the rules determinating hemodynamics after revascularization surgery for complex intracranial aneurysms
Clinical Application of Echocardiographic Blood Flow Visualization System

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2011.04

-

2014.03

HAYASHI TAIYU, KATO Hitoshi, GOJO Satoshi, UMEDU Mitsuo, SEN Itsu, YOKOTA Hajime

　View Summary

Dissipative energy loss (EL) of the left ventricular intracavitary blood flow can be obtained using VFM analysys, a novel echocardiographic technology. EL reflects the efficiency of the blood flow, and would be an index of cardiac function. The aim of this research project was to establish the normative value of EL in children.We revealed that both the systolic and diastolic EL had a negative correlation with age and a positive correlation with HR. In addition, the diastolic EL was positively correlated with the E wave peak velocity. We derived the regression equations, in which the systolic EL was predicted by age and heart rate, and the diastolic EL was predicted by age, HR, and E wave peak velocity. Although the clinical implications of EL within the LV in the assessment of cardiac function are currently unclear, our study provides reference values for systolic and diastolic EL that can be used by future studies examining patients with various heart diseases
Establishment of a simulation method to evaluate a software of blood flow distribution in artificial grafts

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2011.04

-

2014.03

KONOURA Chikako, UMEZU Mitsuo, YI Qian, INOUE Nobuyuki, IRISAWA Yusuke

　View Summary

We propose novel evaluation criteria for assessing aortic revascularization surgery from the standpoint of regulatory science using computational fluid dynamics (CFD).In order to know the blood flow distribution in the body, we measured blood flow in the aortic arch of healthy individuals and aortic aneurysm patients by phase-contrast magnetic resonance imaging (PC-MRI). We created human blood vessel models from the MRI images of the aortic arch, and simplified branch models that represent the vessel geometry after revascularization. We used the models to examine the CFD boundary conditions corresponding to PC MRI images and established a method to analyze blood flow distribution. We also examined the computational limitations of our simplified models
Preoperative simulation of pediatric cardiac surgery analyzed by computational fluid dynamic study

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2011.04

-

2014.03

SHIKATA Fumiaki, NAGASHIMA Mitsugi, OKAMURA Toru, HIGAKI Takashi, OKURA Masahiro, UMEDU Mitsuo

　View Summary

Early survival after Fontan procedure has improved dramatically for the development of perioperative surgical treatment and strategy based on each surgeon's experience and scientific data. Despite of these improvement, there are still concerns about long-term complications, i.e. pulmonary arteriovenous malformation and thrombus formation in the conduit, which can less the quality of life after surgery. We simulated the optimal design of procedures with computational fluid dynamics to gain the better quality of survival and the optimal anastomosis was developed both in Fontan and Glenn procedure. This technique could be applied to designing of the different type of pediatric cardiac surgery, which is expected to lead the better quality of life after surgery
Developement of a new stentless mitral valve for clinical application

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2011.04

-

2014.03

YAKU Hitoshi, SAWA Yoshiki, UMEZU Mitsuo, NAKATANI Satoshi, HASHIMOTO Kazuhiro, KASEGAWA Hitoshi

　View Summary

1) Animal Experiment: We evaluated hemodynamic function of the stentless mitral valve with echocardiography in an acute phase using 8 pigs. No significant mitral regurgitation was found, and the mean mitral pressure gradient during diastole was low, which indicated excellent hemodynamic performance of the stentless mitral valve. 2) Clinical Trial: Nine patients underwent mitral surgery using the stentless mitral valve. All patients went well, and showed no significant mitral regurgitation. The mean mitral pressure gradient was reasonably low; however, it has a tendency towards increasing as time elapses. We continue to follow those patients carefully. 3) Advertisement and Propagation: We organize an annual meeting for stentless mitral valve to report our early and late surgical results and to discuss issues surrounding the stentless mitral valve. The registration system of patients undergoing the stentless valve was established
抗血栓性評価の新展開

Project Year :

2012.04

-

2013.03

　View Summary

抗凝固剤の種類，抗凝固剤の投与量，血液接触材料の組み合わせの違いが抗血栓性に及ぼす影響を臨床で1人のヒトで調べることはできず，またin vitro実験系でも報告はほとんどない．本研究では同一個体から採取した鮮血を用い，各々2種類の抗凝固剤，薬剤投与量，材料を組み合わせた計8条件下での抗血栓性を同時にin vitroで定量比較評価することを目的とした．研究は倫理委員会の承認を得た．1人の健常ボランティアから採取した血液に抗凝固剤のヘパリン，アルガトロバンを活性化凝固時間（ACT）が各々約200秒，500秒になるように予め定めた量を加え，抗凝固剤，投与量2種類ずつの組み合わせから4種の血液を用意した．採血後直ちに4種の血液を臨床使用されている内径12.7mmの2種類の体外循環用チューブ，polyvinyl chloride (PVC)チューブ（チューブA），poly(2-methoxyethyl acrylate)でコーティングしたPVCチューブ（チューブB）に入れ，空気を完全に排除した．チューブを183rpmの一定速度，37℃で10分間回転させた．計6人の血液を用い、全て清潔操作で行った．血液側の評価として回転前後の血液の凝固能，血小板活性，材料側の評価としてチューブ回転後にチューブ表面に吸着した血漿総タンパク量を定量，チューブ表面に吸着した血球成分を走査型電子顕微鏡で観察した．血小板活性を示すplatelet factor 4，beta-thromboglobulinの回転前後の変化は抗凝固剤，ACT，材料の組み合わせにより異なった．材料表面に吸着したタンパク量は，同じ抗凝固剤と同じACTでの比較ではチューブAがBより多かった．以上より，本試験法で抗凝固剤，投与量，材料の異なる組み合わせが抗血栓性に及ぼす影響を，同一の血液を用い，同時にin vitroで定量比較評価できた
自己治癒能力を引き出す無細胞化組織実用化のための総合的基礎研究

Project Year :

2012.04

-

2013.03

　View Summary

本研究は,自己治癒能力を引き出し,体内で自己細胞が入り込み自己組織化が期待できる再生促進型無細胞化腱を独自の組織無細胞化技術を駆使して開発するものである.実用化を目指した総合的基礎研究の中で,コア技術として,力学的特性の維持を実現する組織の保存・滅菌法が未解決課題であった.無細胞化組織を凍結乾燥して滅菌し,手術場で生理食塩水で再水和して使用するコンセプトで研究を推進している.初年度は,水との結合に着目して組織前処理法について詳細に検討し,凍結乾燥してエチレンオキサイドガス滅菌すると変化してしまう組織の粘弾性特性を未処理組織と同等に保持できる組織前処理条件を確立した(国際特許出願).また,我々が開発した非臨床超急性免疫反応評価法を駆使し,無細胞化処理して滅菌処理したウシ由来心膜に対するヒト血液の超急性免疫反応を,臨床で使用されており安全性が確認されているグルタールアルデヒド溶液で処理されたウシ心のう膜パッチ製品,及び,ポジティブコントロールとして未処理ウシ心膜を抗生物質で洗浄した組織と比較評価した.実験前に再水和させた無細胞化及び滅菌済みウシ由来心膜と共培養した血液のラクトフェリン濃度は,グルタールアルデヒド固定処理されたウシ心のう膜パッチと同程度であった.C3a濃度も同様の結果となり,補体活性が抑制されることを定量的に示すことができた.さらにsC5b-9濃度は,グルタールアルデヒド処理されたウシ心のう膜製品と比較して,無細胞化処理して滅菌したウシ心膜の方が活性が抑制されることが判明した.合わせて,本実験系で,未処理組織はいずれの指標も顕著に上昇することを確認した.無細胞化処理後に確立した方法で前処理し,凍結乾燥してエチレンオキサイドガス滅菌したウシ腱を用い,第一例目の大動物前十字靭帯再建術をヒツジで実施し,6ヶ月間問題なく機能することを実証できた
Development of an artificial papillary muscle recovering left ventricular functions

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2011.04

-

2013.03

SHIRAISHI Yasuyuki, YAMBE Tomoyuki, MIURA Hidekazu, UMEZU Mitsuo, HOMMA Dai

　View Summary

We developed an artificial papillary muscle by using covalent-type Ni-Ti anisotropic shape memory fibres. We could achieve the development of a tissue-rubber hybrid left ventricular model including native heart valves. Subsequently we could investigate optimised mechanical interactions between mitral valve leaflets and the left ventricle with the artificial papillary muscle reducing mitral valve regurgitation
Cerebral aneurysm rupture risk estimation of with artery thickness.

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2010.04

-

2013.03

YI Qian, UMEZU Mitsuo, MURAYAMA Yuichi

　View Summary

Anew approach using the technology of solid-liquid interaction model to estimate the risk of aneurysm rupture was performed under hemodynamic conditions. Flow energy loss in aneurysms was significantly different between ruptured-aneurysms and stable-aneurysms. The preliminary study found that greater energy loss occurred when flow passed through ruptured aneurysms, when compared to unruptured aneurysms. This new concept of energy loss may become a useful tool for the prediction of aneurysm rupture. These preliminary results indicated that EL may be a useful parameter for the quantitative estimation of the risks of rupture for aneurysms
Enhancement of the Differentiation of Cardiomyocytes from Mouse Embryonic Stem Cells and Creation of Ventricular Model based on modification of scaffold

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2010.04

-

2013.03

FENG Zhonggang, NAKAMURA Takao, UMEZU Mitsuo, KOSAWADA Tadashi

　View Summary

This research deals with the two critical issues for the realization of the clinical use of ES/iPS cells in the treatment of heart failure: one is the effective differentiation into cardiomyocytes from ES/iPS cells, and another is the creation of cardiac tissue equivalent. By the integration of stem cell engineering, protein engineering, and tissue engineering, a novel method for fabrication of natural-ECM included scaffold layer was developed; differentiation into cardiomyocytes was enhanced on this scaffold; and furthermore, cardiac tissue equivalent was created through stacking multi such layers. The above experiments have brought out findings in the differentiation of mouse ES cells into cardiomyocytes, in the effect of mechanical characteristics of scaffold on the differentiation, and in the construction of cardiac tissue equivalent
An innovative treatment approach supporting development of surgeons' imaging by the TAAA Navigator

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2009

-

2011

AOMI Shigeyuki, UMEZU Mitsuo, NAKAMURA Ryoichi, SUZUKI Takashi, UEMATSU Miyuki, MURAGAKI Yoshihiro

　View Summary

We have developed a surgical navigation system called "TAAA Navigator", which is especially designed for aortic vascular surgery. The system consists of functions that are based on our recent studies : a multipoint-based registration algorithm on bone structure, a correction method of tissue thickness, a reference marker system tracking bed position, and a target detection method using both external and internal points on body. In this paper, we report a newly applied registration algorithm to correct errors derived from the tissue thickness of patients. A model formula was provided to analyze error factors on tissue thickness. The error components were divided into the average value and the deviation value. In this algorithm, the average value was regarded as the offset of tissue thickness and the deviation value was as the weight of the measurement. A phantom examination showed the offset was effective. To reveal the efficacy of the weight, further discussion would be needed
Development of a passive-active artificialmyocardium reconcilingthe physiological demands with hemodynamic changes

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2005

-

2009

SHIRAISHI Yasuyuki, YAMBE Tomoyuki, SAIJO Yoshifumi, UMEZU Mitsuo, FUJIMOTO Tetsuo, BABA Atsushi, TABAYASHI Koichi, HOMMA Dai

　View Summary

We developed a sophisticated artificial myocardium which consisted of shape memory alloy fibre units. We applied the PID method for the control of myocardial assist, and examined the dynamic performance as well as hemodynamic changes in goats. It was anticipated that the passive-active artificial myocardium control could be achieved which was reconciling the physiological demands with pathophysiological diagnosis by using our new methodology.
Development of newly designed pressure sensor for regenerative medicine and artificial organs

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2006

-

2008

FUJIMOTO Tetsuo, UMEZU Mitsuo, NISHIDA Hiroshi, SHIMIZU Tatsuya, SHIRAISHI Yasuyuki
The research and development of durable decellularized aortic valves in collaboration with engineers.

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2006

-

2008

OZAKI Shigeyuki, OHZEKI Yasuhiro, UMEZU Mitsuo, IWASAKI Kiyotaka, SASAKI Nobuo
Construction of engineered cardiac tissue possessing the contractile characteristics of in vivo myocardium

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2004

-

2007

FENG Zhonggang, NAKAMURA Takao, UMEZU Mitsuo

　View Summary

This research project is aimed at constructing, based on collagen gel scaffold, engineered cardiac tissue (ECT) that will possess the contractile characteristics of in vivo myocardium. Through 3 years' studies, we obtained the following results and achievements.
1. By comparing the mRNA and protein expression of some vital transcriptional factors and constitutive proteins of intercalated disc in cultured cardiomyocytes with those in myocardium in vivo, we showed that the transcriptional factors, SRF and myocardin, and the constitutive proteins, N-cadherin and connexin43, were at lower expression levels in cultured cardiomyocytes than in the tissues in vivo. It suggested that the attenuation of these molecules may impede the further differentiation of the cardiomyocytes under culture condition and that the formation of intercalated disc of engineered cardiac tissue may be in defect. The weak contractile force of ECT is also considered to mostly owe to the above lower expressions. Based on these findings, gene transfer technology was employed to enforce the expression of N-cadherin in cultured cells to enhance the interaction between adjacent cardiomyocytes.
2. Permeability of the collagen gel sold was increased by the addition of heparin and albumin. With such modified collagen gel, nutrient provision and metabolic waste excretion are improved 4 kinds of additives, heparin, albumin, fibronectin, and fibrinogen were added to collagen gels, respectively, and the permeability of glucose through the gels were measured. The results showed that heparin and albumin were able to increase the permeablity by about two folds.
3. A series of experiments were conducted to carefully search for the optimal conditions to each step of the ECT creation procedure. It came out that the following two treatments were necessary besides prior published protocol: I) the addition of cysteine into culture medium would help to diminish the residual effect of collagenase after cell harvest from natural heart tissue and in gel making process, ii) to prevent the embedded cardiomyocytes from depositing at and attaching to the bottom of culture dishes, the gels should be inverted once just after gelation.
4. A novel electro-tensile bioreactor was developed to promote the continuation of cardiomyocytes differentiation and the maturation of 3D tissue under culture. Differing from the former one developed by us, this new type imposed tensile stress by resisting, with an ingenious way, the contraction of the ECT which is induced by electrical pulse stimulus, rather than directly stretching the ECT. Therefore, the electrical stimulus, contraction strain and contraction stress were orderly occurred in the ECT the harmony of electrical stimulus and the tensile stress was reached by means of the inherent electro-contraction mechanism.
5. We invented an algorithm based on the theory of elastic string vibration to calculate the contractile force in the ECT versus to time, strain, and strain rate, respectively. By analyzing the contraction displacement of the ECT in ring shape, this method provided an effective approach for revealing the characteristics of ECT contraction and can detect quite small contractile force to 1 μN
6. Through the above innovations and improvements, the contractile force exerted by the ECT was increased by 16 folds, and it presented the characteristics that the maximal contractile force preceded the maximal contraction strain but corresponding to maximal strain rate, which is quite similar to the characteristics of natural heart muscle contraction.
Flow field analysis of the flow around and inside the valsalva and of the coronary flow influenced by the prosthetic aortic valve

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2005

-

2006

AKUTSU Toshinosuke, MITSUMASA Umezu, NIINAMI Hiroshi, IWASAKI Kiyotaka

　View Summary

The purpose of this research is to grasp the influence of the leaflet and overall design differences on the flow field inside the valsalva and to clarify the influence of these differences on the coronary flow when the valve is equipped at aortic location. By utilizing the previously developed Aorta and experience accumulated in constructing simulation device, new Aorta model simulating aortic characteristic was planned and constructed and used it to analyze the influence of overall valve and leaflet design on the flow field inside the valsalva and on the coronary circulation by using DynamicPIV system
In the first research year, we planed to construct prototype Aorta model and planed execution of pre-experiment to establish analytical method using DynamicPIV system. Pre-experiment using newly constructed prototype Aorta model was executed using the MIRA valve and the SJM valve as test valves, resulted in finding substantial differences on the generated flow.
Above-mentioned new analytical method was purposely tried at trusted mitral valve location, where enough data was accumulated for evaluation, to find the influence of the valve designs on the mitral flow field. Some results were already reported through international and domestic conferences.
In the last research year, we constructed final silicone Aorta model with valsalva. It was equipped in the simulation device and experiment was conducted. As a result, flow field influenced by the mechanical bi-leaflet valve was obtained in detail and was able to grasp the flow phenomenon inside the valsalva. With this time-resolved information in hand, we were able to grasp the influence of flow field to the coronary circulation.
Development of evaluation system for artificial organs from the viewpoints of clinical study, engineering, and statistics.

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2003

-

2005

FUJIMOTO Tetsuo, UMEZU Mitsuo, OWASAKI Kiyotaka, KAWAZOE Kohei

　View Summary

A circulatory simulator was developed in order to evaluate artificial organs such as ventricular assist systems, artificial heart valves, and arterial prosthetic grafts from the view point of hemodynamics. Some experiments were conducted to demonstrate characteristics of a rotary pump used for a right ventricular assist system and a newly designed aortofemoral prosthetic Y graft in the simulator. As a result, it was revealed that there was definitely an incremental increase in the branch diameter increasing the flow rate through the graft. In this study, a newly designed pressure transducer and an expandable tube for clinical application were devised. The former is enough small to be fixed into artificial organs in which the pressure can be measured. The latter was designed to expand the diameter of the tube as a tracheal tube and a cannula for left ventricular bypass. These inventions are lodging patent applications. In addition, a new database system was developed in order to analyze clinical data statistically. Clinical data including pulse wave velocity (PWV) were analyzed actually by the system and it was revealed the tendency that the risk of the death increases accompanied by increase in PWV as a result. It is supposed that the combination of the simulator and the database system will be useful to evaluate artificial organs from the viewpoints of clinical study, engineering, and statistics.
Establishment of support technology for the development of surgical training simulator

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2002

-

2005

UMEZU Mitsuo, KAWAZOE Kouhei, IWASAKI Kiyotaka

　View Summary

In order to discuss a selection criteria for surgical technique on cardiovascular diseases, it is effective to make use of a mock circulatory system. In this study, mitral regurgitation is focused for the development of surgical training simulator. At first reproduction of mitral regurgitation was achieved. Then quantitative evaluation of the mitral valvuloplasty were performed as an application of the in vitro simulator.
1.Reproduction of mitral regurgitation
A fresh porcine mitral valve with chordae and papillary muscles was installed into the mitral position of the mock circuit. The evaluation system is capable of simulating various mitral conditions by changing the valve orientation. The normal model was implemented with the papillary muscle in the same configuration as in a natural heart. In contrast, the prolapse model was produced by severing anterior marginal chordae. As a result, valve closure similar to a natural heart was successfully attained in the normal model.
2.Evaluation of the effectiveness of mitral valvuloplasty
A comparative test was conducted to evaluate the effectiveness of mitral valvuloplasty techniques for the repair of an anterior mitral leaflet prolapse. In order to correct the prolapsed portion of mitral valve, the chordal replacement (replacement model) and the edge-to-edge technique (Edge-to-Edge model) were applied by an experienced surgeon. After the application of the two, the prolapsed portion was corrected in systole, and a double orifice area of E-to-E model was observed in diastole.
In conclusion, it has been confirmed that the mock system developed in this study can provide useful data for cardiac surgeons. As the data can be treated quantitatively, surgeons and biomedical engineers can discuss on the scientific basis.
生命科学・医工学統合研究に基づく未来医療への挑戦的研究

文部科学省

Project Year :

2001

-

2005
1ヶ月保証の超低価格血液ポンプの実用化を阻む要素の徹低解明

科学研究費助成事業(早稲田大学) 科学研究費助成事業(萌芽研究)

Project Year :

2002

-

2004

　View Summary

補助人工心臓は重症心不全患者に対して有効な治療手段であるが,高価格であり,またその利用が高度先進医療施設に限定されることから適用数は極めて少ない.このため,急性心不全といった短期間での回復が期待される症例に対しては,有効な医療デバイスが国内において存在しない現状にある.本最終年度は,真空成形法により大量生産技術を確立した旋回渦流型拍動血液ポンプを基盤とし,どの市中病院でもほぼ常備している大動脈バルーンパンピング用駆動装置(IABP駆動装置)を流用して臨床で要求される性能を満足すべく,駆動装置のアタッチメントを開発した.あわせて,カニューレのプロトタイプを作製してポンプシステムとしての総合的性能を明確化した.IABP駆動装置を用いた際には,人工心臓用駆動装置と比較して1.5倍の溶血量が生じることが判明した.この原因として,IABP駆動装置による駆動圧力波形の急激な変化による血球へのダメージが考えられた.そこで,駆動圧の最大,最小圧及びdP/dtを低減させること目的に,ニードル弁・圧力タンクで構成する一次遅れ系要素を応用した圧力制御ユニットを開発した.このユニットをポンプと駆動装置の間に接続するだけで,ポンプの拍出量は維持したまま駆動陽・陰圧をそれぞれ32%,55%減少させることができた.さらに,人工心臓用駆動装置を用いた場合と比較して溶血量を7.4%減少させることに成功した.あわせて,患者の精神的負担と感染リスクを低減させることを目的とし,内径が体外部19mm,皮膚貫通部10mm,体内部12mmという皮膚貫通部のみを細径化したカニューレを設計・製作して性能試験を行った.その結果,本ポンプシステムで5L/minを超える平均流量の確保が可能であることが判明し,各要素の開発はほぼ完了した.今後,動物実験を行い,解剖学的フィッティングを包括してカニューレを開発する必要がある.
生物学をベースとした骨格系運動生理モデルの構築と医療応用

文部科学省

Project Year :

2000

-

2004
Investigation of Usefulness of "Recovery-Directed Left Ventricular Assist Device" invented based on a new concept

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2001

-

2003

MIYAWAKI Fujio, UMEZU Mitsuo, TAKATANI Setsuo, FUKUI Yasuhiro

　View Summary

Recovery-Directed Left Ventricular Assist Device (RDLVAD) is a new type LVAD characterized by remarkable reduction in ventricular afterload during systole and no restriction of ventricular relaxation or dilatation during diastole, thereby promoting cardiac recovery. It consists of a valved apical conduit, a compliant afterload-controlling chamber (ACC), and a continuous-flow type blood pump. In both experiments using a mock circulation and isolated perfused rabbit hearts, we investigated sizes and properties of the main components that are appropriate for RDLVAD to achieve the above features.
1.In the state of severe left heart failure represented in the mock circulation, the effect of each of 12 combinations made between 3 different apical valves and 4 different ACCs on the left ventricular pressure (LVP), the ACC pressure and the maximum cardiac output was studied. The apical valves, 9 and 13 mm in internal diameter, were too small to reduce the ventricular load. The 18-mm apical valve, whose opening area was 60% of that of the 23-mm aortic valve, and the ACC half as large as the stroke volume were smallest for constantly achieving significant reduction in ventricular afterload and sufficient blood supply ; the developed pressure as low as a mean systolic LVP of 27mmHg and a peak LVP of 47mmHg was capable of producing a maximum cardiac output (=maximum pump flow) of 5.8L/min even if the compliance of ACC was as low as 0.1-0.6mL/mmHg.
2.We have warned that continuous-flow type LVADs increase the risk of impeding ventricular relaxation and filling as a pump flow rate rises. This phenomenon was shown both in the mock circulation and animal experiments. In some isolated hearts, heart rate also suddenly increased when the pump flow was raised. On the other hand, the RDLVAD did not restrict ventricular relaxation or filling.
Develop of High Performance Stents

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2000

-

2003

MATSUDA Takehisa, FUJII Yasuo, SHIMOKAWA Hiroaki, SUEISHI Katsuo, NAKAYAMA Yasuhide, UMEZU Mitsuo

　View Summary

This project aimed to develop high performance stents which enable to reduce the hyperplasia in diseased coronary arteries. Two new approaches were designed and tested : One approach is covered stent in which microporous segmented polyuretheve thin film is wrapped on the stent to prepare a covered stent on which high photoreactive coating enabled sustained release of an incorporated drug. The in vivo study verified that heparin release eventually reduced the intimal hyperpleasia. The other approach is to delivery endothelial progenitor cells (EPC) autologously harvested from the circulating peripheral blood. EPC "paving " from the EPC-seeded stents resulted in full endothelialization at denuded arteries, resulting in rapid wound healing. Thus, the project was completed with high outcome.
Experimental Comparison of End-to-Side and Side-to-Side Anastomosis for Coronary Artery Bypass Grafting

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2000

-

2002

NIINAMI Hiroshi, UMEZU Mitsuo

　View Summary

Recently, arterial conduits, such as internal thoracic arteries and the right gastroepiploic artery are being used extensively for coronary artery revascularization to obtain better long-term patency. To use these grafts, end-to-side anastomosis (ESA) is generally utilized to attach the bypass graft to the native coronary artery. Due to the small caliber of these conduits, a slit must be made at the end of the graft to obtain a sufficiently large anastomotic area. However, with side-to-side anastomosis (SSA) a larger anastomotic area can be obtained for arterial conduits, and therefore we have been performing SSA clinically for coronary artery bypass grafting (CABG) with arterial grafts for several years. In this study, we conducted experiments on ESA and SSA to determine the performance and characteristics of these anastomotic methods, to provide practical information for surgeons and to facilitate the selection of anastomosis for individual patients.
Hemodynamic tests of the two different types of anastomoses (ESA and SSA) were carried out in both in vitro and in vivo settings. In the in vitro study, two different anastomotic models were constructed from transparent siliastic tubes, and hemodynamic parameters were measured using a mock circulation device. Moreover, we conducted a comparative study to support the in vitro data using numerical flow simulations. These simulations were validated against experimental data using the flow visualization technique. In the in vivo study, CABG was performed in five adult pigs under cardiopulmonary bypass. Bilateral internal thoracic arteries were inserted into the right coronary artery using ESA or SSA for each graft. After weaning from cardiopulmonary bypass, hemodynamic measurements were obtained, as in the in vitro study.
Energy loss was calculated from the graft flow rate and the pressure loss between the native coronary artery and bypass graft. In the in vitro study, the energy loss for SSA was 23.8% lower than that of ESA. This was reproduced in the in vivo study in which reduction of 44.8% was observed. The result of numerical analysis and flow visualization indicated the existence of a stronger vortex in ESA compared with SSA.
Less disturbance and lower flow resistance were observed in SSA than in ESA based on the level of energy loss and observation of flow fields, which suggests that SSA has a smoother anastomotic geometry for flow than ESA. This might affect the inhibition of intimal hyperplasia, which could lead to a better long-term patency rate of the coronary bypass conduit using SSA compared with ESA when arterial conduits are used.
Establishment of production process of cellular- type oxygen carriers

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

2000

-

2001

TAKEOKA Shinji, SAKAI Kiyotaka, NISHIDA Hiroyuki, TSUCHIDA Eishun, SAKAI Hiromi, UMEZU Mitsuo

　View Summary

In order to establish the large-scale production process of cellular-type oxygen carriers (hemoglobin (Hb)-vesicles), the following subjects were finished.
1. Carbonylation and deoxygenation process of the Hb solutions : The carbonylation (CO) and deoxygenation of a hemoglobin (Hb) solution were performed with an artificial lung.
2. Electrochemical deoxygenation of the HbO_2 solution : The dissolved oxygen (pO_2<1O Torr) was electrochemically reduced to water under the diluted hydrogen/ nitrogen mixture gas condition.
3. Ligand-exchange process of HbCO to HbO_2 : The Ligand-exchange process was carried out by visible-light irradiation to the HbCO solution using a liquid thin film or a silicon hollow fiber module.
4. Synthesis of new aminolipids and the use : The polyoxyethylen-conjugated or negatively-charged aminolipids were newly synthesized and the Hb-vesicles were prepared with these lipids.
5. Scaling up of an extrusion process : To improve the efficiency of the extrusion process, the mixced lipid dispersion was previously freeze-mawed and -dried. The necessary time during the extrusion process of the dispersion of the powder to the Hb solution was largely reduced, and the efficiency of the extrusion was also dramatically increased with the multistage-combined type extruder.
6. Evaluation of the 10L-scale production of the Hb vesicles : The apparatus in an each process was lined, and me 10L-scale production of the Hb vesicles are being evaluated. The pilot plants on the scale of 300 L will be planned.
体育学分野におけるセンシング技術の現状調査と将来予測

科学研究費助成事業(早稲田大学) 科学研究費助成事業(基盤研究(C))

Project Year :

2000

　

　

　View Summary

ヒトの体力・健康度を精確かつ簡便に測定・評価するために、現代社会において求められているセンサ技術とはどのようなものか、体育学分野で現状調査を行い、理工学系の研究者とともにその将来予測を行った。体育学系ならびに理工学系の研究者がそれぞれ、「現在使用されているセンサの現状調査」、「センサに対するニーズを整理・分析」、「センサに対するシーズの調査・分析」の3つのグループに分かれて調査研究を進めた。
「現在使用されているセンサの現状調査」グループでは、センサ機器メーカの検索や体育学分野で活動する研究者に対するアンケート調査からセンサ技術の現状や問題点を把握した。「センサに対するニーズを整理・分析」グループでは、調査によって明らかとなった問題点から社会のニーズに貢献しうる技術について論議を行った。「センサに対するシーズの調査・分析」グループでは、現時点で実用化に近い技術を整理した。
また、生体機能測定に関連する施設及びセンサ機器を視察するために産業医科大学を訪問し、同大学の研究者と意見交換を行った。さらにオーストラリアへ渡り、パース市のThe University of Western Australia、シドニー市のNew South Wales Institute of Sportを訪問し、それぞれ研究者に施設を案内してもらい、現在使用している実験機材について説明を受けた。
これに加えて、現在日本の体育学分野で用いられているセンサ技術についての知識を得るために、講師を招聘して特別講演を開催した。講演後の討論からその応用とこれからの可能性について考察した。
以上のことから、健康度や体力の評価を簡便にでき、なおかつ軽量で身体に装着可能な携帯端末(ウェラブルセンサ)のニーズが高いことが明らかになった。今後はウェラブルセンサ機器を中心に調査を進める予定である。
新鮮な血液を用いた機械加工表面性状の定量評価の試み

科学研究費助成事業(早稲田大学) 科学研究費助成事業(萌芽的研究)

Project Year :

1999

-

2000

　View Summary

第3年度は,人工弁・人工心臓などの開発の早期に血液適合性をある程度評価でき,また,設計改良の指針となるデータを得ることが可能な,より信頼性のあるin vitro血液適合性評価試験回路の開発を目指した.
第一に,回路内での血液と空気の接触面を完全に排除した4つの同一形状の旋回渦流型血液ポンプで構成される一巡閉鎖回路を開発した.4つの血液ポンプのうち1つのみを駆動し,他の1つはコンプライアンス,残りの2つはリザーバの役割を持たせることで,平均大動脈圧100mmHg,平均ポンプ拍出量2.5L/minといった実際の使用環境に近い試験環境にすることができた.また,washout性能の極めて良好な旋回渦流型血液ポンプを回路の構成要素として用いることで,流れの停滞領域のない試験回路を開発することができた.第二に,チューブやコネクタなど試験回路の構成パーツに対する血小板の活性能を同一にするために,血液ポンプと同一材料で回路内面全体をコーティングした.なお,本研究では新開発の高分子製二葉弁を血液適合性評価試験対象とした.
開発した回路内をヘパリン化した新鮮牛血液で満たし,その後プロタミンで中和してACTを300sec〜400secに調節した後に試験を開始した.採取した血液中の血小板の活性能時間を考慮して,試験は4時間で終了した.試験後の弁葉表面をSEMによって観察した結果,(1)弁流出側の弁葉表面では血球成分の付着及びフィブリン網などが全く観察されず血液適合性は良好であったが,流入側の弁葉表面では弁閉鎖時にスポークと接触する部分の吸着タンパク質層に磨耗跡が観察された.また,(2)弁座と弁葉の接着部分に血小板の付着が観察された.以上から,新たに開発したin vitro血液適合性評価試験回路は製品開発の早期に問題点を明確にするのに極めて有効であることが明らかとなった.
人工臓器素材開発

文部科学省

Project Year :

1996

-

2000
体力・健康度に対する定量的評価の確立に向けての調査研究

科学研究費助成事業(早稲田大学) 科学研究費助成事業(基盤研究(C))

Project Year :

1999

　

　

　View Summary

健康・体力の定量的評価の確立を目指して、その定義や評価方法について3つのグループに分かれて調査研究を行った。「計測グループ」では身体活動レベルに応じた生体機能データの計測法について主にセンサ技術に対する調査を行い、現在使用されているセンサ技術の現状や問題点を把握し、さらに社会のニーズに貢献しうる技術について論議を行った。同時に、計測対象となる生体信号について、その種類と関係をまとめた。「分析グループ」では生体機能の分析について、循環器のモデル解析および最適化問題等を中心に研究を進め、循環系シミュレータについての知見をまとめた。「治療・評価グループ」では健康・体力の評価方法について計測結果の評価の仕方や運動処方のあり方、健康管理について調査し、意見をとりまとめ総括を行った。
さらに、体育学系と工学系という立場からワーキンググループを構成し、体育学系においては使用経験のあるセンサの問題提起を行い、工学系においては定量化に有用な既存技術についての調査を行った。
加えて、筑波宇宙グループを訪問し、現在の日本における宇宙飛行士の生体機能・体力測定についての評価方法について、そして、富山県国際健康プラザの訪問では、健康度の評価法についてそれぞれインタビューを試みた。フロリダ州オークランドでの調査では、アメリカにおける医療保健機構や組織について、健康の定義と捉え方について日本との比較を行った。
また、歩行動作のシミュレーション技術についての知識を深め、その応用とこれからの可能性について考察した。
今後は、体育学分野におけるセンサ技術のニーズを整理し、工学分野でそのシーズを調査・分析して、健康度や体力評価を簡便にできる身体に装着可能な携帯端末(ウェラブルセンサ)について調査研究を行っていく予定である。
生体模倣部品開発プロジェクト

文部科学省

Project Year :

1999

　

　
Analysis of flow behavior of blood-biomaterial interfaces

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1998

-

1999

UMEZU Mitsuo, FUJIMOTO Tetsuo

　View Summary

Shear stress, which is a tensor value, is regarded as an essential factors of hemolysis, but hemolysis level is a scalar value. Therefore. the authors proposed energy dissipation rate E (J/m^3) as a generalized substitute for shear stress and have formulated the following expression for plasma free hemoglobin.
H=kE^αt (where, k and α are constant values, H : hemoglobin level)
In addition, the difference in the threshold shear level due to the type of stress, namely viscous and Reynolds stress, is believed to be related only to the exposure time. Therefore, preliminary in vitro hemolysis test has been performed using to clarify the effects of laminar and turbulent flows on hemolysis.
In the present experiments, two types of suspension media with different viscosities were used to examine a sufficiently wide range of Reynolds numbers without altering hematocrit or exposure time. Bovine red blood cells were suspended in saline for turbulent flow condition and in dextran solution for laminar flow condition. The viscosity of the suspensions were 1.56cP and 5.20cP, respectively. Blood was circulated for 90 min under the shear stress of 100-500 Pa.
Blasius friction factor was calculated to verify flow condition as a laminar or turbulent. The experimental results exhibited that hemolysis rate under turbulent flow was four times higher than that under laminar flow, suggesting that the effect of viscous and Reynolds stress on hemolysis is not always equal. Then, it became possible to consider that energy dissipation took an important role to predict a level of hemolysis.
Prediction of durability of artificial organs using an accerelated fatigue tester

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1997

-

1999

UMEZU Mitsuo, AKUTSU Toshinosuke, KITAMURA Nobuo, KAWAZOE Kohei, UCHIYAMA Akihiko, FUJIMOTO Tetsuo

　View Summary

In order to predict a durability of heart valve prostheses, two types of commercially available (ISU-Standard) accerelated fatigue tests were employed, while improving a life time of Jellyfish polymer valve.
A chronic animal experiment of Jellyfish valves incorporated into conventional sac-type blood pumps for over 300days exhibited that there were a fracture and calcification on this flexible membrane. Therefore, a long durability (approx. 1 year guarantee) of Jellyfish valve has been developing. while clearing a cause of the problems.
First of all, design improvement of Jellyfish valve was attempted. Results of finite element analysis during closed phase of Jellyfish valve indicated that mechanical strain generated on valve membrane fracture and calcification in the animal experiment. Moreover further analysis suggested that an additional circular rim located at 7.0mm in radius was quite effective to avoid strain concentration. In vitro steady and pulsatile tests demonstrated that a modified valve with 0.5mm width rim located at 70mm in radius had a comparable hydrodynamic performance to the original Jellyfish valve.
For the next step, commercially available two types of accelerated fatigue tests were employed. Fatigue tests successfully revealed that a durability of the modified valve was much more extended than the original Jellyfish valve by 7 times.
Thus, chronic animal experiment with conventional sac-type blood pumps in which the modified valves were incorporated was performed for months. Hemolysis related to the application of the modified valve was not observed. This would be owing to the tapered configuration of the additional rim with 0.1mm width of inflow side.
From the data above, the modified polymer valve showed great promise for clinical artificial heart application, and it was also clarified that our prevent fatigue tester could provide comparative durability data of polymer valves.
Development of a mock circulatory system as a supporting tool to propose the oprimal cardiac surgery

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1997

-

1999

UMEZU Mitsuo, FUJIMOTO Tetsuo, KAWAZOE Kohei, KITAMURA Nobuo, MASUDA Hiroshi, UCHIYAMA Akihiko

　View Summary

An originally-designed mock circulatory system (MCS) has been developed in order to evaluate functions of several types of artificial organs for the surgical treatment of cardiovascular deseases. The features of the present MCS has a capability of exhibiting a practical simulation of hemodynamics in aortic vascular prostheses, and of having a mechanical feasibility of the natural left ventricular contraction by the computer-based control.
As mechanical properties of arterial vascular grafts are different from those of elastic natural arteries, it can be speculated that the left ventricular afterload might be elevated after the graft implantation due to its low compliance. By switching blood flow to a bypass graft which was inserted in parallel with the natural descending aorta of dog, the characteristic impedance was elevated by 2.6 times, furthermore, the cardiac output was decreased by 14%, and the cardiac work calculated from the pressure-volume relationships in the left ventricle, was increased by 1.5 times. MCS was also employed to represent hemodynamic characteristics as well as to compare the data with those in animal experiments. When the flow was set to 4L/min in MCS by the mechanical driven pump, either characteristic impedance of the arterial system or external work of the left ventricular model was increased by 2.4 or 1.5 times, respectively. Thus, it was anticipated that the external cardiac work would be elevated by the increase of the arterial impedance after the graft implantation.
Development of viscoelastic tubes similar to blood pump

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1995

-

1996

UMEZU Mitsuo, FUJIMOTO Tetsuo, TOMIOKA Jun, TEOH S.H, CHEW Y.T

　View Summary

The purpose of this study was to fabricate viscoelastic tubes, which was anatomically identical and functionally equivalent to the natural aorta. A rotational molding workstation which was originally developed at the National University of Singapore was used for this research. First of all, we tried to fabricate aortic arch-shaped tubes by a conventional method ; a single rotational axis was employed after silicone liquid was painted onto the mold by a brush. However, it was hard to make an even thickness tube, and it was also hard to control the quality. For the next step, several trials and errors were conducted using a rotational molding workstation under various combination of rotational speeds between two axis with different painting volume, interval and times. At last, the optimal condition to develop 1mm-thickness tube was determined as follows : rotational speeds of major and minor axis were 0.02rpm and 8rpm, respectively, a weight of silicone was 20g each for three times, and painting interval was 3hours. Then, thickness deviation which was defined as a ratio between standard deviation and average thickness culd be reduced from 30% to 20%.
It was well-known that natural aorta had specific mechanical properties ; increase in pressure is small for the range of less incremental volume, whereas it becomes more for the range of higher incremental volume. We have tried to fabricated multi-layr tube, however, we haven't get a favorable result. So, other trials that contained different properties from silicone was carried out. A sponge layr was sandwiched with soft and stiff silicone layrs. The compliance values of this 3-layr tube was 0.41 1/mmHg in the range of small incremental volume up tp 40%, but it was decreased to 0.36 1/mmHg for over 40%, due to a shift of major elasctic effects from outer stiff to inner soft silicon layr.
Above findings were worthwhile for the further improvements of the rotational molding machine.
Development of spiral-vortex-type blood pump (Optimal design and its application to cardiomyoplasty)

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1994

-

1996

NAKAMURA Takao, FUJISAWA Naoki, NUGENT Allen, SCHINDHELM Klaus, UMEZU Mitsuo

　View Summary

A spiral-vortex-type blood pump is one of the promising pumps having the best fluid dynamic characteristics to control the thrombus formation inside the pump. To develop a total system of the pump and for an application of it to the cardiomyoplasty, following studies have been conducted.
(1) A new system for the measurement of pump flow was designed, based on a principle that the electrical capacitance of electrodes attached to the pump surface changes depending on the blood volume inside the pump. A preliminary test in vitro has shown excellent results.
(2) An economical method for the fabrication of the blood pump has been designed, using vacuum forming and injection molding. Using the technique, several pumps with different physical shapes were fabricated, and basic performance of them has been tested and compared with each others for the empirical optimization of pump shape.
(3) A new economical ball valve with plastic housing has been designed for the blood pump application. A preliminary test in vitro has proven an excellent fluid dynamical performance of the valve.
(4) Effect of rough surface of polymer materials on the thrombogenisity have been analyzed quantitatively. The surface of the polymer was fabricated quantitatively textured (physical length and interval) with laser beam, and the polymer has been implanted in sheep. The experiments are still on the way.
(5) Basic mechanical characteristics (energetics) of the pump diaphragm have been analyzed for the future application of cardiomyoplasty.
(6) Flow pattern inside the pump has been measured by laser Doppler anemometry. The analyzing software has been developed, and the results have been displayd in animation.
(7) Acute animal experiments have been conducted for test the feasibility of blood pump system. The pumps have shown excellent spiral-vortex inside the pump.
Development of a Internationally acceptable fatigue test system for prosthetic heart valve

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1994

-

1996

UMEZU Mitsuo, NAKANO Kiyoharu, HAYASHI Junichi, KAWAZOE Kohei, TOMIOKA Jun, KAWADA Hiroyuki

　View Summary

The purpose of this study is to establish an internationally-acceptable methodology of fatigue testing for prosthetic heart valves, based on the improvement process of a Chinese-made accelerated fatigue test apparatus. This test system had four parallel water cylinders, in which valves were incorporated. Open and closing motion of each valve was controlled at a repetition speed of 10-20 Hz with a displacement of 1-2mm. The Jerryfish (JF) valve was used in this study. It had the longest implantation record in animal trials. In this case, the polyurethane membrane with the thickness of 50-70 mum was ruptured due to a creep effect observed at the middle portion between two spokes after 300days in goat.
First of all, in vitro fatigue test machine has been innovated in order to reproduce the above mentioned in-vivo fatigue test results. Dynamic conditions which enabled the identical forces between accelerated and normal cycles were determined : maximum load during valve closure was 5.2N (increased by 20% to the normal), and impulse was 2.5*10^<-2>N・s. Under this condition, valves were ruptured for 1.0*10^7 cycles, but no distinct creep was noticed. Secondary, a temperature of the test-fluid was changed from 20ﾟC to 50ﾟC,expecting a creep effect to the membrane shape. Change in shape of the membrane was observed after 3.2*10^6 cycles, however, its distortion value was only 50% of the animal experimental results. For the next step, a material of the membrane was changed from polyurethane to polystirene to achieve bigger change in shape. As a result, the identical distortion level was successfully reproduced, but a location of the ruptured area was different between in vitro and in vivo results. In order to clarify the above mentioned difference, FEM analysis was performed. The calculated result exhibited that there are three major areas of the maximum elastic strain between two spokes. Moreover, it was confirmed that the ruptured areas observed by both in vitro/in vivo results could be fully superimposed to the areas of the calculated maximum elastic strain.
Further investigation should by carried out to determine more reliable methodology for fatigue testing, based on the in vitro and FEM analysis data.
循環系および運動系の力学的解析に基づくウェイトリフティングの最適訓練法の提唱

科学研究費助成事業(早稲田大学) 科学研究費助成事業(一般研究(C))

Project Year :

1995

　

　

　View Summary

ウェイトリフティングを題材とする本研究では,運動負荷に対する循環系の力学応答の情報計測法を確立し,末梢における循環系の特性を工学的に表現することを目的としている.運動負荷の入力情報が瞬発的で明確なその基礎検討として,ウェイトリフティングと同じく,運動負荷の入力情報が瞬発的で明確なダンベルの使用,トレッドミル上での走行,跳躍などの単純運動をまず対象とし,応答特性解析を試みた.
実験では,短時間の運動負荷による小さな変化を測定するために,測定速度・測定精度・非接触性に留意した.体表温度測定には非接触測定が可能なサーモカメラを採用した.センサー部で発生するノイズは,高速な測定速度を利用した断続移動平均法により,測定速度1〔秒〕以下,測定精度が0.1〔℃〕程度の高性能の測定系となった.また,皮膚血流測定にはレーザードップラー血流系を採用した.皮膚血流変化を,測定速度1〔秒〕以下,測定精度1〔ml/min/100g〕程度で採取することができた.
生理学では,皮膚血流量が皮膚温度を制御するとされている.しかし,運動負荷に対する短時間の末梢循環の応答は,その限りではないことが実験結果から明らかになった.このような現象を,温度の違う血流の流入配分に起因するものと考え,皮膚温度と皮膚血流の関係を探った.運動負荷実験の結果,筋温度は鋭いピークで一瞬上昇し,逆に皮膚温は急激に下がってなだらかに回復したのに対し,筋血流と皮膚血流は共に運動負荷中に上昇する傾向を示し,前述の血流流入配分と皮膚温度の関係を裏付けるような結果となった.上記をはじめとする数々の実験を経て,末梢における循環系の,運動負荷に対する振る舞いをある程度把握できるようになったが,最適訓練法を提唱するには,まだ多種のパラメタの変動の相互関係を取得してゆくことが必要であることが同時に確認された.
Developed of spiral vortex-type artificial heart

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1991

-

1993

UMEZU Mitsuo, SEKI Junji, NUGENT Allen, NAKAMURA Takao

　View Summary

The Australian pulsatile ventricular assist device (VAD) has been named the "Spiral Vortex" (SV) pump after the continuous streamlines which develop within the pump housing during operation. In the chronic animal experiments performed in Australia, the SV pump was placed on the left side of the sheep's body. In a regular course, an experimental sheep can stand up in a few hours after the operation. The sheep can eat, drink and sleep in the container for the duration of the experiment. During VAD pumping with the bypass flow of 3.0-4,0 L/min, the level of plasma free hemoglobin was less than 10 mg/dl. At present, animal experiments are underway to confirm the superiority of the system in near "real-world" conditions. However, optimization of the SV design must be achieved through an engineering analysis prior to the development of a clinical quality model.
In order to obtain fundamental data on the SV design, a comparative flow visualization study was planned in Japan using two different SV housings. Hydrodynamics test revealed that no significant difference in pump flow and inlet waterhammer between cone-shaped and dome-shaped SV pumps. However, outflow velocities in the cone-shaped pump were consistently lower than that in the dome-shaped during systole. and, peripheral flow velocities in the cone-shaped were also lower during diastole. Then, the domeshape recommended during the diastolic phase for decreasing the stagnation at D-H junction, whereas the cone-shape was recommended during the systolic phase for minimizing shear stress. The optimal SV housing design should be approached in the light of this data.
Development of a permanent use completely implantable total artificial heart system

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1986

-

1988

AKUTSU Tetsuzo, NODA Hiroyuki, KINOSHITA Masayuki, NAKATANI Takeshi, TAKANO Hisateru, TAKATANI Setsuo, KONISHI Tsutomu, UMEZU Mitsuo

　View Summary

The objective of this research was to develop a permanent use completely implantable total artificial heart system. Because of the risk and social problem associated with a nuclear power system, the motor driven system that utilizes eelectrical energy has been proposed to attain this goal. The system consists of a transcutaneous power transmission system, electrical motor driven total artificial heart(TAH), internal power storage system and controller and a compliance sysytem.In this research, feasibility of the motor driven heart and transcutaneous energy transmission system have been evaluated on the bench top mock circulatory loop. The transcutaneous energy transmission system has been constructed utilizing a litz wire and formed in a bount shape. Since the inner and outer diameter of the coil and number of turns, separation distance between the primary and secondary coils, alighnment of the center axis all affect the transmission efficiency of power, they were tested one by one prior to test in the animal and application to powering the electric heart. The maximum transmission efficiency of about 70% was obtained through the thoracic skin of goat. As an electric motor heart, a low speed and high torque DC brushless motor was selected. In order to convert the rotational motion of the motor to a recti-linear one, cylindrical cam was designed. As a control mode, in order to closely mimic the natural heart ejection pattern, leftand right simul-taneous ejection mode was selected. Thus, a double cam follower mechanism to realize this left-right simultaneous ejection mechanism was newly designed and fabricated and tested in the mock circulatory loop. This DC motor and cylindrical cam assembly was placed between the two pusher-plate type blood pumps that have a maximum stroke volume of 60cc. the bench top test demonstrated that the maximum pump output of about 9 1/min can be obtained against the left pump afterload of 100mmHg and right pump afterload of 25mmHg. the maximum electric heart efficiency was about 15%. This electric heart was powered by the transcutaneous energy transmission system in the bench top circulatory simulation system. it was confirmed that electric motor heart as powered by the transcutaneous energy trans-mission system can yield satisfactory performance to meet the original design goal. The endurance testing of the electric motor heart is under test and the to date the maximum run time of the system is approximately 10 days.
全人工心臓(TAH)置換動物における循環維持と制御に関する研究

科学研究費助成事業(国立循環器病センター) 科学研究費助成事業(一般研究(A))

Project Year :

1986

-

1988

　View Summary

本年度は、空気駆動式全人工心臓の駆動制御に必要な人工心臓機能監視装置の性能の検討と、臨床使用を考慮し、解剖学的FITTINGに優れた日本人用全人工心臓の試作と慢性動物実験による検討を行なった。
人工心臓システムの制御性と操作性の向上のために、駆動ラインに組み込んだ空気流量計の、1)非侵襲的かつ連続的な人工心臓機能の監視、2)自動完全駆出、完全充満(Full-fill・Full-empty)モードでの駆動、3)人工心臓拍出量の計測、への応用について模擬回路および動物実験で検討した。その結果、空気流量計により、正常駆動時と人工心臓異常時に特徴的な流量波形が検出され、人工心臓の駆動状態の監視と異常の診断への応用の可能性が示唆され、また、空気流量計からの信号を用いて、自動Full-fill・Full-emptyモードでの駆動が安定して行なわれた。加えて、拡張期の空気流量波形を解析することにより求めた人工臓拍出量の計測は、電磁流量計による測定との間で高い相関と、ほぼ1:1の関係を示すことを明かとした。
日本人の胸腔内の心臓周辺の寸法を核磁気共鳴断層撮影像を基に測定し、ヒトの解剖学的特徴を考慮してヒト用空気駆動式全人工心臓を試作した。抗血栓性の向上と胸腔内の寸法の制限に対処するために、大血管および心房と人工心臓を結合し、同時に人工弁を把持するコネクターのデザインも同時に改良した。体重53kgの子牛を用いた慢性動物実験でシステムの評価を行なったところ、胸腔内への装着は容易であった。また、術後急性期は中心静脈圧、左房圧、大動脈圧などの臨床的に一般に使用されるモニタを用いたが、それ以後は上述した人工心臓機能監視装置からの信号と駆動装置から得られる駆動圧波形の観察のみで循環動態の管理を行なっている。実験動物は術後23日目現在元気に生存しており、システムの優秀性が示された。
Experimental and clinical studies of ventricular assist system for acute profound heart failure.

Project Year :

1986

-

1987

　View Summary

In this project, the following three tasks were performed.
(1) Therapeutic effect of VAD on bi-ventricular failure(BVF): the therapeutic effect of VAD on BVF were evaluated in experimental study. BVF was induced by aortic-clamping under normothermia in goats, and LVAD (8 goats) or BVAD (2 goats) was applied. Without the pulmonary hypertension, LVAD alone in combination with volume loading could maintain near normal circulation. In case of BVAD, it was easy to maintain the circulation without volume loading. The recovery possibility of BVF depends upon the severity of myocardial damage suffered before VAD application. (2) VAD for pediatric use; two sizes of airdriven, diaphrahm type VADs have been developed for pediatric use. Their stroke volumes were 20 ml and 40 ml. With mock loop test, sufficient output for pediatric use was obtained. In amimal experiment using dogs weighing from 10 to 20 kg, the conduit could be smoothly inserted into the left atrium and easily sutured to the aorta. (3) Development of a non-invasive and continuous monitoring method of cardiac output during LVAD pumping: In order to develop a method that can predict left ventricular stroke volume from arterial pulse pressure and pressue-flow relationship on the VAD, three methods were evaluated in a mock circulatory loop. As the pressure-flow relationship, arterial compliance, peripheral vascular resistance, and arterial impedance were used in the first, second, and third method, respectively. In comparison to electro-magnetic flowmetry, the 2nd and 3rd methods showed excellent correlation coefficient.
Based on the above results, VADs were applied for 16 patients with cardiogenic shock. In nine of them entire circulation was well maintained at normal level and LVAD was successfully removed. Although the natural heart could recover, the most patients died of multiple organ failure which developed during prolonged ischemia prior to LVAD assistance. In clinical situation, timely use of LVAD by right judgement is important.
Development and evaluation of motor-driven, pusher-plate-type artificial heart system

Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research

Project Year :

1984

-

1986

HAYASHI Kozaburo, NAKAMURA Takao, SEKI Junji, UMEZU Mitsuo, TAKANO Hisateru, AKUTSU Tetsuzo

　View Summary

A pulse width modulation (PWM) algorithm with fixed duty ratio and variable voltage has been developed to drive and control the implantable electro-mechanical actuator for blood pumps. The actuator incorporated with a dc brushless motor was attached to a pusher-plate-type blood pump. Rotation of the motor is converted into a linear motion by a ball screw. The position of the pusher-pate was monitored with a Hall-effect sensor mounted on the back plate and a magnet attached to the plate. Any other monitors are not necessary for the open-loop operation of the pump. The size of the actuator is 50 mm OD and 30 mm length, and the weight is 480 g. Eight-bit and sixteen-bit microprocessor-based systems were used to drive the motor and to control the whole system, respectively.
The torque performance of the motor assembled in the actuator was studied in detail for the development of the software which controls the speed and the input voltage of the motor without any feed back informations. The results indicated that the pump fulfills the specified performance.
Software was developed based on the results obtained from the torque test. The sixteen-bit microprocessor controls the operation of the pump, monitoring the position of the pusher-plate in the systolic phase and using a timer in the diastole. The eight-bit microprocessor controls the phase of rotating magnetic field and input voltage of the motor according to the data table derived from the torque test.
The system performance studied with a mock circulator satisfied the design specifications. The pump outflow of 6 1/min was obtained at the rate of around 100 bpm against the afterload of 100 mmHg. The temperature rise and the pump efficiency were around 6 % and 18 C, respectively.
臨床に直接貢献できる実用型小児先天性心疾患の血流シミュレーションシステムの構築

　View Summary

我々は数値流体解析(CFD:computational fluid dynamics)の手法を用い、Norwood手術での血流動体を解析し、最適な術式を検討した。Norwood手術は今日最も重症な先天性心疾患である左心低形成症候群に対して生後早期に行う手術であり、今日最も難易度が高い手術の一つとされる。Norwood手術では大動脈を再建するが、これまでに様々な再建術式が報告されている。また再建後大動脈の曲や吻合部口径など形状の違いが心負荷、遠隔期予後に影響を与えるとされるが、その詳細は不明であった。まず、我々は小児の動脈内での拍動流を解析する手法を確立した。NorwOod術後患者の3D造影CTデータ(DICOM data)より患者に特異的な形状を作成し、心臓超音波検査で計測された血流データを境界条件として用い、3次元非定常Navier-Stokes方程式を解くことで解析を行った。解析結果を患者の心臓カテーテルデータで得られた血圧データを用いてvalidationを行った。末梢での反射波を想定することでより精度の高い生理学的な拍動流が実現された。この手法を用い、術式の異なる10症例の術後データを用い、CFD解析を行った。解析結果からエネルギー損失と血管壁にかかるshear stressを評価した。エネルギー損失は心拍出仕事量の約3～13%を占めることがわかった。遠位弓部に狭窄を伴う症例や、再建後の大動脈弓の角度が急峻になる症例では大動脈弓でのshear stressが高く、大きなエネルギーを損失した。パッチを用いる、下行大動脈に縦切開を置くなどの工夫をし、なだらかで狭窄のない大動脈弓が再建された症例ではエネルギー損失が低くなり、心負荷を軽減する可能性が示唆された。この解析システムが遠隔期予後を念頭に置いた術式の評価や術式の選択の上で非常に有用である可能性が示唆された

▼display all

Industrial Property Rights

無細胞化方法及び人体移植用人工組織

太田友博, 岩崎清隆, 梅津光生

Patent
生体組織の処理方法及び生体組織

6078838

岩崎清隆, 梅津光生

Patent
血液適合性等の評価用の実験方法

5561130

岩崎清隆, 梅津光生, 東宮裕人, 利根川明宏, 宮川充

Patent
模擬血管製造用のモールド、模擬血管の製造方法、及び模擬血管

4974253

田中隆, 岩崎清隆, 梅津光生

Patent
移植用人工弁尖及びその製造方法

梅津光生, 岩崎清隆, 尾崎重之

Patent
保存処理時の生体組織の保持方法及び保持具、並びに保存処理された生体組織

5424147

岩崎清隆, 梅津光生

Patent
模擬狭窄血管及びその製造方法

5136993

岩崎清隆, 梅津光生, 坪内俊介, 濱悠太朗, 八木下雄一

Patent
ステントレス人工僧帽弁及び人工弁葉

5392539

梅津光生, 加瀬川均

Patent
外科手術訓練装置

梅津光生, 朴栄光, 白石泰之, 本間大

Patent
冠動脈バイパス手術用の訓練評価システム

梅津光生, 朴栄光, 白石泰之, 岩田浩康

Patent
生体組織形成維持装置

5136977

岩﨑清隆, 梅津光生, 小島浩司, チャールス・バカンティ

Patent
医療訓練用血管モデル及びその製造方法

4404963

梅津光生, 朴栄光

Patent
医療機器の耐久試験装置及び耐久試験方法

5051234

岩崎清隆, 梅津光生, 錦織晃, 坪内俊介

Patent
血管動作シミュレータ

4822335

岩﨑清隆, 梅津光生, 長谷川厚, 錦織晃

Patent
血管動作シミュレータ

4822521

岩﨑清隆, 梅津光生, 長谷川厚, 錦織晃

Patent
血管動作シミュレータ

4968822

岩﨑清隆, 梅津光生, 長谷川厚, 錦織晃

Patent
血管動作シミュレータ

4968821

岩﨑清隆, 梅津光生, 長谷川厚, 錦織晃

Patent
手技訓練用血管モデル

4326011

梅津光生, 朴栄光, 三田裕, 沖恵理子, 金光直彦

Patent
移植用生体組織

岩﨑清隆, 梅津光生

Patent
心臓シミュレータ

梅津光生, 高西淳夫, 西川員史, 朴栄光

Patent
荷重センサ及びそれを用いた荷重の検出方法

梅津光生, 高西淳夫, 西川員史, 朴栄光

Patent
細胞播種方法

梅津光生, 岩﨑清隆, 尾崎重之, 守本祐司

Patent
生体組織の保持装置及びこれを用いた生体組織処理装置

梅津光生, 岩﨑清隆, 尾崎重之, 守本祐司

Patent
血流シミュレータ及び流れ変換装置

4587776

梅津光生, 白石泰之, 有田誠, 川合潤子, 末弘淳一, 田中隆

Patent
血液ポンプユニット

梅津光生, 岩﨑清隆, 井街宏, 石原一彦

Patent
脱細胞化方法及び生体組織処理装置

4444918

梅津光生, 岩﨑清隆, 尾崎重之, 守本祐司

Patent
医療用具の拡張力測定用保持具

4120959

梅津光生, 有田誠, 大森謙一

Patent
流体循環装置

4165691

梅津光生, 岩﨑清隆

Patent
生体左心室の収縮形態を模擬した左心室サック及びその製造方法

4144014

有田誠, 白石泰之, 梅津光生, 東野純大

Patent
人工冠動脈及び冠動脈ステント性能評価シミュレータ

4166905

梅津光生, 堀切芳一, 丹治一幸, 曽我新吾

Patent

▼display all

Overseas Activities

機械工学のバイオメディカルへの応用研究

2009.03

-

2009.09

ニュージーランドカンタベリー大学

Internal Special Research Projects

ステントレス僧帽弁の世界初の臨床応用を通じた医工学評価・予測技術の体系化

2013

　View Summary

我国の僧帽弁手術は半数が人工弁置換、残りは外科的トリミングによる弁形成術である。僧帽弁置換術においては、人工弁置換による左心室機能の低下、弁輪サイズの制限や長期間の抗凝固療法といった課題が残されている。このような状況を改善するために加瀬川均医師(榊原記念病院)と共に考案したのがヒト僧帽弁構造と類似した構造を有するステントレス僧帽弁(NORMO弁)である。ステントレス僧帽弁は弁尖がステントに拘束されることなく、弁膜・乳頭筋の連続性が保持されるという世界に類を見ない独創的な人工弁である。この弁は榊原記念病院と京都府立医大の心臓血管外科、循環器内科との共同研究で合計8例の患者に臨床を実施している。いずれの症例でも逆流は劇的に解消し、弁前後の圧較差は低く維持され、現在まで良好な経過で推移している。一方で、心臓内科医によるエコー検査によれば術直後と比較すると狭窄気味であると指摘された症例もあり、手術場での手造りのため、品質にばらつきがあることが考えらえる。このばらつきの要因としては、(A) NORMO弁のデザインまたはマテリアル由来、(B) 心機能のリモデリング由来、(C) 外科手技の術技由来の3点が考えらえる。本研究では(A) マテリアル由来に注目し生体材料の構造力学解析手法の確立に取り組んだ。特に、NORMO弁に負荷するひずみを実験的・数値的に明らかにするため、(1) 多粒子トラッキングを用いた非接触でのひずみ分布計測法の検討、(2) 有限要素法を用いたひずみ分布算出のための解析条件の検討を行った。以下にその結果を概略する。(1) 多粒子トラッキングを用いたひずみ測定方法の検討　φ60mmの円形に切出した未処理のウシ心膜に銅粒子(90～150μm)を等間隔に付着させ、荷重を与える前後の粒子の形状および分布の変化をマイクロCTで撮像し画像解析によりひずみを測定した。その結果、中央部で最大ひずみ(0.249)が発生することが明らかになった。実験で用いたモデルに対し有限要素法を適用してひずみを算出し比較した。その結果、心膜中央部では同様の傾向を得た。一方で、心膜固定の縁付近では異なるひずみの傾向を示すことが明らかとなった。これは検査領域が粗く、表面積算出時の誤差が大きいことが要因と考えられ、検査領域を狭めることにより高精度での測定が可能であることが考えられる。以上より、生体材料のひずみ測定に多粒子トラッキングを使用できることが示唆された。(2) 有限要素法を用いたひずみ分布算出のための解析条件の検討　ウシ心膜製のNORMO弁を空気圧にて閉鎖することにより、NORMO弁閉鎖時のひずみ解析モデルを取得した。形状はマイクロCTにて3次元的に計測し、得られたデータを基に3次元立体構築ソフトMimicsを用いて構築した。モデルの前尖と後尖は分離してあり、臨床の弁に近い構造とした。有限要素解析時の境界条件として弁輪、脚部先端を完全固定とし、左心室内圧を考慮して弁葉に120 mmHgの圧力を作用させた。エレメントサイズと次数の異なるメッシュ条件で解析を行い相当応力の最大値の比較を行った。その結果、エレメントの次数によって前尖の弁葉では相当応力に最大18%の差が生じることが明らかとなった。エレメントサイズを0.4 mmから0.2 mmに変更しても、相当応力の値は0.4 mmの2次要素を使用した結果と一致しなかったことから、エレメントの次数が解析結果に影響を与える要因の一つであることが明らかとなった。また、NORMO弁では前尖の脚部に最大応力が発生する可能性が高いことが判明した。　以上の結果から、ステントレス僧帽弁の臨床応用を通じて明らかとなった課題に対する医工学評価・予測技術の体系化に向けた基礎を構築した。
医療レギュラトリーサイエンスの学問構築を支える究極型循環シミュレータの開発

2012

　View Summary

　日本胸部外科学会の報告では,弁膜症手術数は1997年から2009年の間に約2倍に増加しており,弁膜症外科治療の重要性は今後も増していくと考えられる.僧帽弁置換術においては,人工弁置換による左心室機能の低下,弁輪サイズの制限や長期間の抗凝固療法といった課題が残されている.このような状況を改善するために加瀬川均医師(榊原記念病院)が考案されたのがヒトの僧帽弁構造と類似したステントレス僧帽弁(NORMO弁)である.ステントレス僧帽弁は弁膜・乳頭筋の連続性が保持され,弁尖がステントに支持されないという世界に類をみない独創的な人工弁である.本研究では,ステントレス僧帽弁の流体性能を評価するため, 空気圧駆動装置を内蔵した拍動型循環シミュレータを用いて (1)機械弁とステントレス僧帽弁の流量性能比較評価,(2)弁吻合位置が拍出流量に与える影響の検討,(3)弁葉の形状が流量性能に与える影響の3点を検討した.以下にその結果を概説する.(1)機械弁とステントレス僧帽弁の流量性能比較評価　ステントレス僧帽弁の普及を目指し開催されたトレーニングセミナーにより,未経験医師が初めて製作した弁を用い性能評価を行った結果,比較対象とした機械弁（N=7）の平均流量は3.55±0.12L/minであったのに対して,加瀬川医師が製作したステントレス僧帽弁（N=8）の平均流量は4.72±0.35L/minと圧倒的に高い流量を拍出できることがわかった.一方,未経験医師が製作したステントレス僧帽弁4個はそれぞれ4.32 L/min,3.85 L/min,3.64 L/min, 3.35L/minであり,ばらつきがあった.しかし,未経験医師が製作したステントレス僧帽弁1個を除き,すべての弁が機械弁と同等以上の性能を示した.低流量であった弁に関しては,外科的に弁葉に改良を加えたことで流量が3.75L/minとなり,機械弁と同等以上の流量が確保できた.(2)弁縫合位置が拍出流量に与える影響の検討　ステントレス僧帽弁植え込み時における乳頭筋部への縫合位置が拍出流量に与える影響を検討した結果,縫合位置が心臓壁側において流量が最大となり,ステントレス僧帽弁の乳頭筋への縫着位置は現在採用されている心臓壁側が妥当であることが判明した.(3)弁葉の形状が拍出流量に与える影響の検討　ステントレス僧帽弁の弁葉の形状が拍出流量に与える影響を検討した結果,弁葉の切り込み形状を2～8mmの範囲で変えても弁性能は3.44～3.81L/minで大きな影響を与えないことが分かり,未経験医師でも十分に性能の良好な弁を製作できることが判明した.以上のごとく,循環シミュレータの応用の一つとして,新しいコンセプトのステントレス僧帽弁(NORMO弁)の非臨床データとしての特性の位置づけができたものと考えている.
先進医療の長期効果の予測を目指した究極の血液循環シミュレータの提案

2010 岩崎清隆, 八木高伸

　View Summary

東洋紡績社製補助人工心臓の弁にはSORIN-Carbocast弁（以下，SC弁）が使用されていたがSC弁の生産中止に伴いMedtronic-Hall弁(以下，MH弁)への移行が行われた．ここでは，シミュレータにより弁変更に伴う人工心臓の水力学・溶血特性を調査した．臨床使用のカニューレを模擬したWindkessel回路を用いて，SC弁及びMH弁の性能比較を行った．収縮期時間比のみ20～60%の範囲で変化させ，平均拍出流量と弁近傍の水撃値を計測した．水力学試験の結果に基づき，a)2種の弁において最大拍出流量が得られる駆動条件，b)収縮時間比を下げて2種の弁の流量が同一になる駆動条件で溶血量の比較を行った．豚新鮮血を使用し開始5分後及び1時間ごとの血漿遊離ヘモグロビン濃度，溶血量を示す指標として6時間後のN.I.H (Normalized Index of Hemolysis) を計測した．最大拍出時にMH弁の方が流量で12%，水撃値で14%高値を示し全体的にもMH弁の方が高値を示した．しかし，2種の弁において同一流量が得られる収縮時間比での水撃値はMH弁がSC弁よりも約20%低減した．a)の条件ではMH弁がSC弁よりも72%高値を示した．しかしb)の条件でのMH弁のN.I.H値は0.03g/100Lで，最大拍出時と比べ約33%の低減をすることができた．また，SC弁との比較では約16%高い結果となった．MH弁はSC弁と比較して拍出性能が高いため収縮時間比を下げて駆動してもSC弁使用時の拍出性能を維持でき，かつ水撃の低減を通じて溶血を低く抑えることができる．臨床においてSC弁よりも低い収縮時間比での駆動が適切であると結論づけられた．
臨床医学に直接貢献する外科手術訓練用多層血管モデルの開発

2007

　View Summary

近年、心臓外科領域においては患者、心臓外科医の双方にとってリスクのない方法による、基本的な心臓外科手術手技の日常的訓練手段が求められている。WETLABとは、解凍ブタ心臓を用いた訓練手段であり、生体組織の感触が得られるメリットがあるが、衛生面、および準備等の煩雑さに課題があるため、病院内での日常的訓練手段としては普及が困難である。当研究室では、日常的訓練を実現するため、解凍ブタ心臓を高分子製血管モデルで代替した冠動脈バイパス訓練装置を開発してきた。本研究では、訓練用冠動脈モデルの精密な機械的強度の調節手段を確立するため、シリコーンゴムの均一材料により成形された単層構造の従来型高分子製血管モデルの多層化を行った。具体的には以下の方法により研究を行った。(1)
機械式血液循環シミュレータによる脳動脈瘤の治療支援技術の確立

2007

　View Summary

　脳動脈瘤の破裂は，血流による力学的な刺激が関与していると考えられている．現在の臨床では，瘤を発生部位や大きさ等から評価しており，血流の影響を踏まえた瘤破裂の予測評価技術の確立が求められている．そこで本研究では，破裂及び未破裂瘤4症例の瘤内流れを比較し，破裂に影響を与える流れ要素を検討した．（1）実験対象の選定とモデル内流れの可視化実験対象は，①破裂瘤：72歳最大瘤径6mm②未破裂瘤：54歳最大瘤径16mm ③未破裂瘤：64歳最大瘤径11mm ④未破裂瘤：60歳最大瘤径9mm の4症例とした．これらの3D-DSAデータを内部形状としたシリコーンモデルを，ロストワックス法を駆使して製作し，生体内頸動脈の力学的特性（1.4±0.4×10-3 1/mmHg）と合致するモデルを使用した．ヒト内頸動脈の血流を再現する際には，作動流体に血液粘度と同値のグリセリン水溶液（粘度3.8 cP）を用い，平均流量は330mL/min，心拍数は70bpmとした．時系列PIV法により瘤内の流れ特性を定量的に評価した．（2）モデル内流れの3次元構造破裂例である①での主流はジェット状であり80cm/s以上の高速度を維持したまま瘤壁に沿って直進し瘤頭部に達していた．また，瘤頭部近傍に有するブレブ部分では，主流とは異なる2次流れを形成していた．②では，主流は瘤形状に沿わず瘤内部を通過して瘤頭部に達した．①と同様，ブレブ部分を含め主流の通らない領域において，2次流れを形成していた．これに対し，③と④の流れ形態は共通して①②と異なり，瘤形状に沿った旋回流を主流とし，常時主流の通らない領域はなく，2次流れは見られなかった．　脳動脈瘤の形状は患者ごとに多種多様であるが，本研究により破裂・未破裂の違いに応じて瘤内流れは異なりその特性を差別化できる可能性が示された．今後は数値解析も含め大規模解析を行い破裂・未破裂を差別化する血流パラメータを検討していく予定である．
臨床医学に直接貢献する，外科技術の"匠さ"の定量評価

2006

　View Summary

外科手術手技は“匠の技”とされ，外科医の長期間に及ぶ訓練・経験による培われるものである．近年，目覚しい進歩を遂げている医療ロボティクス技術の更なる発展のためには手術の熟練，すなわち“匠さ”の本質的理解が求められる．本課題では，心臓血管外科領域において一般的な冠動脈バイパス手術における血管吻合手技を研究対象とし，種々の定量評価手法に関する基礎的検討を行った．具体的には次のようなアプローチを採択した．(1) 実体モデルの設計・製作（冠動脈：左前下行枝，グラフト：左内胸動脈）(2) 術野環境を再現する胸腔シミュレータの設計・製作(胸部正中切開下におけるon-beatモデル)(3) 熟練医，及び未習熟医による血管吻合手技の高速度カメラによる撮影，観察．心臓外科医の手術手技データを取得するためには，被験者である医師に対して極度な違和感を与えない程度の術野環境の重要であると考えた．製作された血管モデル（冠動脈，グラフト）は①ヒトと同様の内膜・中膜・外膜による三層構造を有しており，さらには②手技による局所的な負荷により裂開する機械的な脆弱性を付与した．術野環境の再現においては，①外科器械への拘束条件となる開胸面積，②術野深度，③心拍動，④心臓の解剖に基づいた冠動脈モデルの配置を再現した心拍動シミュレータを新たに設計・製作した．これにより心臓外科医に対して違和感を与えることなくin vitroで血管吻合手技が行える環境を整えることができたと言える．本装置を用い，心臓血管外科学会において複数の心臓外科医の血管吻合手技の高速度カメラによる観察を行ったところ，熟練医と未習熟医の差異として，心拍動への柔軟な追従性が異なることが示唆された．高速度カメラによる動画像は画像解析手法により定量的取り扱いが可能であり本アプローチが有効であることが伺えた．
臨床医学に直接貢献する機械式血液循環シミュレータの開発と応用

2006

　View Summary

　脳動脈瘤は破裂するとクモ膜下出血を起こし，そのうち約50%が死亡する危険な血管病変である．従って，脳動脈瘤の破裂やそれに伴う治療について工学的支援に基づく定量的な予測法の確立が期待されている．従来より瘤内流れは破裂に密接に関係する一つの影響因子として考えられてきた．しかし，血管形状の多様性により，破裂する瘤の流れの特性は解明されていない．よって，瘤内の流れを忠実に再現し，流れの特性を系統化することは重要であると考えられる．そこで本研究では，実際の患者の脳動脈瘤の形状と弾性を模擬したモデルを製作した．血流を忠実に再現することで瘤内の流れの特性を理解することを目的とした．　まず，患者の脳動脈瘤の三次元血管造影データからロストワックス法を駆使しシリコーン製の実形状弾性脳動脈瘤モデルを製作した．その力学的特性は単位体積当りのコンプライアンスで評価され，±15%の再現性を持ち，ヒト脳動脈と同等の特性を再現した．また，ヒト内頸動脈の最大流量，平均流量，圧力を模擬した拍動型脳循環シミュレータを製作した．そして，脳動脈瘤内の流れの構造を計測するため，Dynamic PIV可視化実験を行なった．　時系列速度ベクトル解析を多断面で行った結果，瘤付け根のネック部において流入と流出の立体交差が観察された．流出の流れが流入の流れの下に潜り込み，流入の流れの有効断面積が縮小することで加速され，局所的に最大流速が85.1cm/sまで達する領域が存在した．このことから収縮期には流入部血管壁に4Pa程度の壁面せん断応力が加わっていることが示唆された．流入の流れは瘤先端部では常に位置が変動する小さな渦に変化し，不安定な流れとなっていた．このことから，瘤先端部の壁面には周期的な変動ストレスが加わっている可能性が示唆された．本研究より，脳動脈瘤の破裂や治療予後の予測評価のための流れの特性を系統化することが可能となった．
心臓外科手術訓練シミュレータ開発のための支援技術の確立

2001 内山　明彦, 藤本　哲男

　View Summary

本研究は、直視下で弁挙動の観察が可能で、血行動態に基づいた手技の有効性を把握することを目指した僧帽弁形成術評価装置を設計・製作し、現在臨床で使用されている各種人工弁輪の特性比較を行なうことを目的とした。本装置を用いて工学的見地から臨床現場に対して手技選択に関して実証的な根拠を提示することが可能になれば、効果的で質の高い患者中心の医療が実現可能になると考えられる。医療現場に近い環境を構築するために心エコー検査データから頻出する僧帽弁閉鎖不全をin vitroで忠実に再現した。弁輪拡大は、ラテックスラバーに縫合したブタ僧帽弁を後尖方向に10mm伸展することで実現し、弁口面積が約41%増加することがみとめられた。この僧帽弁閉鎖モデルに対して、4つの人工弁輪の比較評価試験を行なった。評価項目は、僧帽弁閉鎖不全症の重症診断に用いられる心収縮期における僧帽弁逆流量及び拡張期における有効弁口面積である。すべての人工弁輪において収縮期における逆流の抑止効果及び拡張期において弁口面積が縮小することが確認された。逆流の抑止効果はClassic ringにおいて顕著に観察され、逆流量の比較において37.3%、弁口面積において15.2%の軽減が見られた。逆に、Duran Flexible ringは逆流量において0.3%、弁口面積において3.4%の減少に留まった。以上のごとく本研究において製作された僧帽弁形成術評価試験装置を用いてin vitroにおいて人工弁輪の有効性を改めて証明することが可能となった。
血液を用いた機械加工表面性状の定量評価の試み

1997

　View Summary

体外循環回路などの人工的な管路内での赤血球破壊（溶血）の力学的要因を分析し、その破壊メカニズムを解明する研究より各種形状の狭窄管路内の溶血を比較することで、溶血の原因が必ずしも剪断力のみによるものではないとの推論を得るに至っている。そこで、本研究では狭窄管の表面粗さに注目して、実際に新鮮血を用いて溶血と表面粗さの関係を求める実験を行い、それと並行して数値シミュレーションによる定常流解析を進めた。実験には溶血実験評価用体外循環回路として用いているものを流用し、狭窄部の表面粗さと溶血の関係を予測するために２つの実験を行った。（１）表面粗さの溶血に及ぼす影響を調べる実験　アクリル製の基準用の狭窄管は表面粗さRa=1.35μmとしていたので、同一形状で新たにRa=0.54μm、Ra=2.00μmの２種の狭窄管を作製し、３者間での溶血の差異を調べた。循環時間６時間までの溶血量は、表面がなめらかなものほど溶血は少ないことが確認できた。（２）狭窄間のどの部分の表面粗さが溶血に大きな影響を及ぼすかを調べる実験　15mmの狭窄部の一部の表面のみRa=1.35μm、他は0.54μmとする４種の狭窄管を作り、実験を行った結果、狭窄部入り口付近での表面粗さが溶血に大きく影響することが確認できた。狭窄部入り口付近において溶血量が多いのは、狭窄部での剥離及び再付着という流れの変化が激しいからと考えられる。そこで、剥離点、再付着点付近の表面粗さが管内の流れに与える影響を調べる目的で有限要素法による数値計算を行ったところ、計算と実験結果のよい一致を見た。1998.10日本ライフサポート学会・発表（予定）1998.10日本人工臓器学会・発表（予定）
人工臓器表面と血球破壊の関係の定量化

1996

　View Summary

　人工管路内を流れる血液に働く種々の外力が、血液中の赤血球破壊（溶血）に与える影響を定量的に評価することを目的として研究を行った。1995年度までの研究成果をもとに、内部表面粗さの異なる狭窄管、内径の異なるチューブ、角度の異なるベンド管を用意した。そして、従来の方式で牛血を循環させ、剥離域における壁面粗さ、血流中のせん断応力、二次流れやレイノルズ応力がそれぞれ赤血球の破壊に及ぼす影響を調べた。　まず、内部表面粗さを0.2～17.5[um]で10段階に変化させた狭窄管を作成した。これを用いた実験では、剥離域の壁面における表面粗さが3[um]程度以下の時に溶血が起こりやすく、4[um]程度以上の時は溶血量は一定の値に収束した。次に、チューブ内径を4.8～12.7[mm]で5段階に変化させた実験では、その溶血量はチューブ内径に反比例し、壁面近傍のせん断応力が影響することが分かった。また、ベンド管の実験では曲がり角度が急なほど溶血量が増えるが、その値は実用的にはほぼ無視できることが判明した。　総合的には、せん断応力による溶血よりも血流の壁面との衝突による溶血が大きくなる傾向があったが、牛血の個体差による実験誤差も大きく、今後の研究ではこの点の再考が必要である。
循環系，運動系の力学的解析に基づく運動能力向上法の提唱

1995 加藤　清忠, 高西　淳夫, 鵜飼　信一

　View Summary

本研究の最終目的は，ウェイトリフティングの最適訓練法を工学的解析をもとに提唱することである。著者らは，運動にかかわる生体の血液循環，特に，筋肉，皮膚の末梢組織循環の応答を工学的に解明するという立場をとってきた。今までの研究によって末梢循環の挙動のごく一部の現象を説明しうる簡単な数式モデルを構築するまでに至った。しかし，それを複数の現象を説明しうる汎用モデルにまで改良を加えるには多くの試行錯誤の過程を踏まねばならない。本研究では，まず重さの異なる（O-19kg）の負荷を足関節で保持したいわゆる等尺性保持運動負荷時の大腿部位の血行動態変化を調べた。この実験では，皮膚血流と皮膚温度の変化をレーザードップラー血流計とサーモグラフィーを用いて計測した。実験の結果，運動に対して皮膚温度は上昇したが，血液量はいつも増加するとは限らなかった。また，同一負荷（10kg）時の大腿部の2ヶ所の部位に対して同様の実験を行った結果，皮膚温度が下降するケースが多く見られた。このような一見不規則にみえる末梢循環の応答特性の現象を説明するには，動脈と静脈の間の末梢部位を筋肉部と皮膚部に分割してとらえ，その2つを結合する血流の存在を考えるのが有効であることがわかった。これは組織学的には穿通枝と呼ばれ，この部位の血液温度は体内深部の筋肉温度を反映するため，皮膚に直接流れる血液温度よりわずかに高く測定される。皮膚温度は，この穿通枝と直接動脈から流れ込む血流の混合の結果によって決定されるという仮説をもとに，実験値を導入した数式モデルを作成した。その結果，運動に対して皮膚温度や皮膚血流量が増減する個々のケースに対してもに本モデルを用いることでその挙動が説明可能であることが示された。

▼display all