Biomedical subjects
Publications and source records attributed to K Tsuchimoto.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The authors have been developing an electrohydraulic total artificial heart (TAH) system with a separately placed electrohydraulic energy converter to minimize anatomic constraints in the pericardial space. Improvements to the system and current status of the development are reported. The energy converter was miniaturized to improve implantability, and its thickness was reduced to 54 mm. System efficiency was increased by suppressing rush current at the time of motor reversal. Maximum cardiac output of the TAH system was 9 L/min, and maximum system efficiency increased to 10%. The blood pump system was implanted easily in the body of a 57 kg calf, and no significant temperature rise on the energy converter surface was observed. As the next step, main components were integrated into a total system. The transcutaneous energy transfer system could supply power to the TAH without a decline in pump performance, and the internal battery could support the system at 6.5 L/min of cardiac output for 1 hour without a decrease in cardiac output. The authors consider the TAH system with a separately placed energy converter the most promising approach to development of a TAH for smaller sized patients.
We applied two different flow visualization techniques to obtain detailed information on the inside flow of the diaphragm blood pump of our electrohydraulic total artificial heart system to determine the optimum washout effect that would result in better antithrombogenicity. Major orifice directions of the inflow and outflow Bjork-Shiley valves of the left blood pump were independently changed to create 17 varied patterns. The character and velocity of the main flow at the diaphragm-housing junction were acquired using a laser light sheet method with polyethylene tracers. Wall shear flow, a major factor governing washout in the blood pump, was estimated by a newly developed paint erosion method. In this method, quantitative evaluation for an index of washout effect was made by calculating the residual ratio of the paint on the blood pump inner surface at 30 sec of pumping. When a single circular flow was consistently observed by the laser light sheet method, the paint residual ratio become low, indicating washout was relatively good. At the lowest paint residual ratio, the center of the circular flow observed by the laser light sheet method was located at the geometric center of the blood chamber. In conclusion, the flow pattern inside the blood pump could be characterized by combined use of these two flow visualization techniques, and the significant role of circular flow in better washout was clarified.
BACKGROUND/AIMS: Immunological status has been considered to correlate to the response to interferon therapy for chronic hepatitis C. The aim of this study was to evaluate the correlation between humoral immunity and long-term response to interferon treatment for chronic hepatitis C. METHODOLOGY: Seventy-one patients with chronic hepatitis C received 10 million units of interferon-alpha 2b three times a week for 24 weeks. Peripheral blood mononuclear cells were obtained before interferon-alpha 2b was administered and were cultured for 7 days. Immunoglobulin concentration in the culture supernatants was measured by enzyme-linked immunosorbent assay and correlation with the response to the therapy was evaluated. RESULTS: Serum ALT levels normalized in 51.4% and hepatitis C virus RNA disappeared in 35.7% six months after the end of therapy. Immunoglobulin production was significantly lower in the patients in whom serum ALT levels normalized than those in whom serum ALT levels remained elevated. The similar result was obtained when efficacy was evaluated on the basis of hepatitis C virus RNA disappearance. CONCLUSIONS: These results suggest that the less humoral immunity, the better response to interferon will be obtained in patients with chronic hepatitis C, meaning that the balance in T-helper function is one of key factors in the response to interferon treatment.