Renal failure is one of the main causes of death for the long surviving animals which replaced totally with an artificial heart (TAH animals). Twenty-eight TAH goats, survived various times from 13 to 880 hours, were studied pathologically.
Focal necrotic areas were often observed at the ischemically colored cortex and on four cases, these necrotic areas were developed over the whole cortex. By means of microangiographic method and others, thrombi were detected more frequently in the kidneys and lungs than in any other organs. The vascular walls where the thrombi were attached to, were often seen to be damaged so that these thrombi were thought to be formed in the local vessels in situ, not in the artificial heart.
The microscopic findings at the kidneys were clas3ified into five groups. The most important findings of them are lower nephron nephrosis and cortical necrosis which indicate the occurrence of long standing vasoconstriction of proximal renal arteries (interlobar art. to interlobular art.).
As a whole, the main pathophysiological status of the renal failure were thought conclusively to be peripheral circulatory insufficiency which would be caused by abnormal hemodynamics, therefore the most essential clinical etiology to renal failure was thought to be artificial heart function itself.
Our application of a new control method to regulate the output of artificial heart brought significant improvement on this point.

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The effectiveness of intra-aortic ballon pumping (IABP) in augmenting collateral coronary flow (CCF) was evaluated using back flow method in acute myocardial ischemia produced by ligation of the canine left anterior descending coronary artery.
IABP resulted in a significant increase of 14% (P<0.001) in CCF in normotensive group and of 39% (P<0.001) in hypotensive preparation (mean BP≤90mmHg).
There was a significant correlation of mean peripheral coronary pressure (PCP) with CCF in ischemic area of it. ventricle (r=0.76, P<0.01) and an increase in mean PCP by 17.4% in hypotensive group was considered to be due to the augmentation of CCF.
During IABP increase in diastolic collateral perfusion pressure was significantly correlated with that in CCF (r=0.49, P<0.01 in normotensive and r=0.84, P<0.01 in hypotensive group) and the pressure-flow responses of the collateral vasculature in the ischemic myocardium was more edpendant on perfusion pressure in hypotensive shock state.
In 8 dogs submitted to 30 min. of IABP, CCF increased 119 to 129% of control values and lactate metabolism of the ischemic myocardium significantly improved.
The increase in CCF and the metabolic improvement were not sustained when IABP was discontinued.

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Inner and outer capsules and intercapsular tufts of high and low porous Dacron vascular prostheses were examined under both light and electron microscopes from 1 to 1, 184 days after implantation in the thoracic aorta of 96 dogs.
Transmission electron microscopic examinations revealed that the collagen fibers were one of the very important elements of them. Three dimensional network structures of the collagen fibers could be observed by means of scanning electron microscopy after enzymatic digestion.The main arrangement of the collagen fibers was found in rows uniformaly parallel to the ridge of each crimp.This phenomenon was similar to that of the intimal smooth muscle cells on the inner capsules whose arrangement was determined by the tension to which they were subjected. The arrangements of the collagen fibers and intimal smooth muscle cells on the high porous graft were more regular than on the low porous one. In parallel, the stabilities of inner capsules of both grafts were examined in respects of nutrition, thickness, mechanical structure and exfoliation.
Results of the examinations of the arrangements and the stabilities suggested that the high porous graft was superior to low porous one.

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The results of this experiment definitely indicate that the cardiovascular internal surfaces have a γ C (Zis.) of 29.0 dynes/cm. and γ C (NON-HYDROGHN BONDING) of 68.5 dynes/cm., which is little smaller than a γ H₂O of 72.8 dynes/cm. and that γ SL is about zero. Also, the following conclusions are derived that the cardiovascular internal surface is hydrophilic as well as hydrophobic, suggesting that deduction that double configuration of the cardiovascular internal surfaces corresponds to the conformation of cell membrane.
On the other hand, it is indicated that the surface properties of expanded polytetrafluoroethylene can be accompanied by the hysteresis of wettability, thereafter resulting in the almost same surface properties on the portion whose wettability is determined by the nonhydrogen bonding homologous liquids (γ C (Zis.)-γ C (NON-HYDROGEN BONDING)-29.0 dynes/cm., γ SL=0 dynes/cm.).
This experiment also obtained the over all patency rates of 93.3% in the superior vena cava, 86.7% in the inferior vena cava and 81.3% in the portal vein replacement. As mentioned above, the pores in the expanded polytetrafluoroethylene venous prostheses play a major role in antithrombogenicity, including the hysteresis of wettability.

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Since the strict control of the blood sugar level of the diabetic patient is essential to prevent the diabetic complications exemplified by the microangiopathies, artificial pancreas, cosisting of the monitor of blood sugar level and automatic injector of insulin coupled with feed back system, is great concern for the treatment of diabetic patients.
In this investigation, blood sugar level is measured with the voltage subtraction circuit by subtraction of the oxygen electrode current from that of the oxygen electrode with glucose-oxydase.
Proportional relationship is recognized between sensor current and glucose concentration from 0 to 250mg/dl, and paralell relationship in the glucose tolerance curves is observed between them in animal experiments.

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The principle of the hemodialysis depends on the phenomenons of both diffusion and ultrafiltration using the semipermeable membrane across the blood and dialysate. In these phenomenons, the small weight molecules of metabolites in the blood are easily removed, but the middle weight molecules of the uremic toxins can be little dialyzed in spite of long time dialysis.
In 1970, Chang et a l has developed the direct hemoperfusion using an albumin-coated, micro-encapsulated coconut activated charcoal on terminal stage of renal failure. The coconut charcoal, however, has a shape of irregular from and soft hardness. Therefore, fine particles freed from the charcoal becomes emboli in the lung.
We have deviced new type of an albumin-coated, micro-encapsulated, bead-shaped activated carbon made from petroleum. This activated charcoal has a spherical form leading micro-encapsulation easily and has strong hardnesss. So that we could not find any emboli in the lung of dogs. Also this charcoal has better absorbent capacity of creatinine and uric acid than coconut charcoal.
Although the charcoal absorbs no urea and water, hollow fiber kidney is applied to this system in series and simultaneous use for removing urea and water and for adjusting an acid-base balance.
Since August 1975, this new dialysis system has been applied on two patients treating with hemodialysis.
During three hours dialysis, reduction ratio of urea, creatinine and uric acid are 43.7, 59.2 and 68.9%. These show two to three times more absorbent capacity than cellulose membrane dialysis.
There is no effect of direct hemoperfusion to all kinds of blood cells; RBC decreased to be 1.25%, WBC decreased to be 8.84% (0.25>p.>0.1), platelets increased to be 1.7%.
These two patients have been kept well with good blood chemical data.

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Three types of hemodialyzer namely coil, plate and hollow fiber kidney are widely used nowadays. Each of them, however, has several weak points. Nephross C-O1 is a coil type dialyzer encased in a cylindrical container and can be adapted to any type of negative pressure console.
Its effective surface area is 9, OOOcm². Sterilization is done by gamma ray irradiation.
In vitro and clinical evaluation revealed that the dialyzer has at least comparable performance to the conventional coil dialyzers presently used.

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