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Biomedical subjects

I Fujimasa

Publications and source records attributed to I Fujimasa.

At least 55 records · Page 3Linked to original sources

[Thermography].

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Breast Neoplasms↗

Pathological studies of the animals replaced totally with the artificial heart. Part I. Concerning lungs, natural heart, and brain.

Pathological studies using routine pathological technics, microangiography and electron microscopy were performed on the 28 goats with an artificial heart (including 2 goats which survived for 30 and 37 days). In this paper, the brain, natural heart, and lungs of the goats were discussed. No special findings were seen in the brain except for rare infarcted areas. The natural heart almost always showed infarction-like lesions in the sub-endocardium and myocardium at the cut surface. The longer the animal survive, these findings became the more serious. The light microscopic findings on the lungs were classified into 6 groups. The most important findings of them are massive, diffuse exsudation with hemorrhage and its changes to chronic status. The main pathophysiological status, causing the pulmonary lesions, seemed to be peripheral circulatory insufficiency with increased permeability of peripheral vessels, especially of venulae. Thrombi were detected more frequently in the kidneys and lungs than in any other organs. The vascular walls where the thrombi were attached to, where often seen to be damaged, so that almost all thrombi were thought to be formed in the local vessels in situ, but not in the artificial heart. The main clinical causes to the pulmonary insufficiency were thought to be surgical operation including anesthesia, functional incompleteness of the artificial heart, etc.

Angiography↗

Pathological studies of the animals replaced totally with the artificial heart. Part II Concerning liver, gastrointestinal tract, kidney, and general discussion.

Twenty-eight goats with an artificial heart (AH) were studied pathologically. Being continued from the previous report, the liver, gastrointestinal tract, and kidneys were taken up in this paper and finally, general discussion was done to get our ideas in shape concerning the pathophysiological status of the goat. Central necrosis of the liver was always observed in the goats which survived for over 140 hours. This finding seemed to be caused mainly by circulatory insufficiency of the portal vein at the latter half of the survival time. Microscopic findings of degeneration, necrosis, and edema were commonly observed at the walls of gastrointestinal tracts, when goats showed poor apetite, mucous feces and constipation. But these problems have been improved by application of a new control method to regulate the output of AH system within a goat's physiological range since October 1974. The lesions seen in the kidneys are classified into 5 groups. The most important findings of them are lower nephron nephrosis and cortical necrosis, both of which indicate the occurrence of long standing vasoconstriction of proximal renal arteries. By means of microangiographic method and others, thrombi were detected frequently in the kidneys. The vascular walls, where thrombi were attached to, were often damaged. Therefore, these thrombi were thought to be formed in the local vessels in situ through renal circulatory insufficiency. The renal pathological lesions have been also improved and severe renal failure from which the previous goats could not escape, has been lessened since the application of a new AH control method. As a whole, the main pathophysiological status of the animals replaced by the AH are thought conclusively to be peripheral circulatory insufficiency. This would be caused by abnormal hemodynamics, so that, the essential clinical etiology is thought to be AH function itself.

Animals↗

Hemodynamic analysis on prolonged survival cases (30 days and 20 days) of artificial total heart replacement.

High output AH pumping causes a marked decrease in hematocrit, as well as peripheral circulatory insufficiency. By the application of a new control method, based on our hypothesis of regulating the output of the pump, maintenance of normal outputs, long term survival, after total heart replacement, has improved from 10 days to 37 days, with the average survival of 18 days. In addition, the experimentsl animals' general condition has been markeldy improved.

Animals↗

Development of a new circulatory assist method with the combined effects of intra-aortic balloon pumping and counter pulsation. First report.

Current circulatory assist methods, such as intra-aortic balloon pumping (IABP), are not always adequate to save acute circulatory failure patients. Therefore, a stronger, percutaneously accessible method is required. We found that the combination of IABP and CP generated a profound circulatory assist effect, and we have consequently developed a new assist system in this study. A sac type blood pump with a volume of 20 ml and a single port without a valve, was developed for CP. In the mock circulatory test, a 20 ml stroke volume was obtained using a cannula with a 5 mm diameter under the following driving conditions: air pressure = 200/-100 mmHg; S/D = 50%; pulse rate = 100 bpm. In vivo experiments were performed using four mongrel dogs with body weights of 12-20 kg. A cannula for CP was inserted via the brachial artery or subclavian artery into the aortic root. The pump flow (PF), coronary artery flow (CF), renal arterial flow (RF), and aortic pressure (AP) were measured, and the combined effects of IABP and CP were compared with their individual effects. In the most effective case, a marked increase in diastolic AP (60%), cardiac output (40%), and CF (100%) was obtained by the combination of IABP and CP, which produced a remarkable effect compared with the single use of IABP and CP. There was no negative effect on RF by this assist method. As this new circulatory support system has many circulatory assist effects, and is percutaneously accessible, it will be available for clinical use.

Animals↗