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A study on a newly designed aortofemoral prosthetic Y graft

Fujimoto T., Nakano S., Iwamura H., Shiraishi Y., Yambe T., Umezu M.

Biocybernetics and Biomedical Engineering

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2008

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Vol. 28, no. 1

59-63

EN

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.

2

Nanotechnology in artificial organ development and its application in diagnosis methodology in baroreflex sensitivity of patients with hypertension

Yambe T., Yoshizawa S., Sugita N., Tanaka A., Imachi K.

Biocybernetics and Biomedical Engineering

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2007

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Vol. 27, no. 1-2

65-70

EN

Space in the human body is so limited that nanotechnology and micromachining technology are the important for the development of the internal artificial organs. Based on the nanotechnology, various kinds of artificial organ development have been performed in Tohoku University including artificial myocardium, artificial heart, rotary blood pump, artificial esophagus, and artificial sphincter. Furthermore, automatic control algorithm for the artificial heart and assisted circulation was applied to the invention of the new diagnosis methodology for the baroreflex sensitivity of the patients with hypertension. Successful clinical application of this new invention was performed. The technical application to the large range is expectable in artificial internal-organs development.

3

Development of implantable probe for observation of microcirculation

Imachi K., Mochizuki S., Baba A., Isoyama T., Saito I., Takiura K., Chinzei T., Shiraishi Y., Yambe T., Abe Y.

Biocybernetics and Biomedical Engineering

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2007

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Vol. 27, no. 1-2

45-52

EN

It is a long-term controversial point between the circulatory physiologists and the artificial heart researchers whether the pulsatile flow is essential for the living body or not [1]. In particular, since the axial flow pump, a continuous flow pump, that could keep the patients alive for more than a few years was introduced into use in clinical setting in 2001, this problem has been regarded as a very important physiological and pathophysiological issue. The objective of this study was to develop an implantable probe to observe microcirculation in artificial circulation. The principle of the probe developed in this study is the following: a thin living tissue is put directly on a highly integrated CCD (charge coupled device), and it is illuminated from the backside of the tissue with LED(light emitting diode). The microvascular nets in the tissue will be projected on the CCD surface, like a contact photograph, which produces an image on the TV screen. The problems are how to magnify them to be able to observe the erythrocyte flow, how to control the focus, how to electrically insulate them and how to make them compact. After several attempts to magnify the image, a micro lens having 2 mm in diameter, 2 mm long and 6 times magnification, was designed and made of acrylic resin. The lens was installed into a CCD camera with 8 mm in diameter and it was 60 mm long. The camera could magnify the image about 650 times on the 14 inches TV screen. A distinct microcirculation image, including the capillary flow, could be observed when the camera was implanted into the connective tissue under the skin of the rabbit. Now the focus control system is being developed with the camera to be implanted in animals on the long-term base.

4

A newly-designed myocardial assist device using a sophisticated shape memory alloy fibre

Shiraishi Y., Yambe T., Sekine K., Ogawa D., Nagatoshi J., Itoh S., Park Y., Uematsu M., Sakata R., Wada Y., Saijo Y., Higa M., Hori Y., Liu H., Wang Q., Konno S., Kuwayama T., Olegario P., Tanaka A., Masumoto N., Ibuki R., Maruyama S., Okamoto E., Fujimoto T., Yoshizawa M., Umezu M., Imachi K., Nitta S.-I., Sasada H., Tabayashi K., Homma D.

Biocybernetics and Biomedical Engineering

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2007

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Vol. 27, no. 1-2

147-154

EN

Recently, the ventricular assist devices are widely applied for a surgical treatment of the final stage of severe heart failure as the bridge to heart transplantation or the destination therapy. However, it was anticipated that the artificial components in the ventricular assist devices might cause the problems concerning thrombosis and infection. As heart failure involves the decrease in myocardial contractile function, the mechanical assistance by using an artificial myocardium might be effective. In this study, the authors developed a mechano-electric artificial myocardial assist system (artificial myocardium), which is capable of supporting natural contractile function from the outside of the ventricle.