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Biomedical subjects

H Kanaide

Publications and source records attributed to H Kanaide.

187 records · Page 11Linked to original sources

Baroreflex sensitivity in patients with Takayasu's aortitis.

Takayasu's aortitis is an arterial inflammatory disease of arteries of unknown etiology. Fainting is a common symptom and has been attributed to ypersensitivity of the baroreflex. We studied baroreflex sensitivity in 11 patients with Takayasu's aortitis and compared it with that of eight control subjects of comparable age. Baroreflex sensitivity was assessed by determining the slope of a regression line relating the rise of systolic arterial pressure to the prolongation of the R-R interval of the electrocardiogram during a transient rise of arterial pressure induced by an intravenous injection of phenylephrine. The average baroreflex slope of patients with Takayasu's arteritis (4.0 +/- 0.8 msec/mm Hg) was significantly less than that of control subjects (10.7 +/- 0.8 msec/mm Hg, P less than 0.001). Reduced baroreflex sensitivity in patients with Takayasu's aortitis may be due to the hardening of the arteries where baroreceptors lie, or to hypertension and/or cardiac disease which was present in most of the patients included in this study. Patients with Takayasu's aortitis who complained of fainting also showed the reduced baroreflex sensitivity. This indicates that fainting in this disease is not likely to be caused by the hyperreactivity of the baroreceptors as is commonly postulated.

Adult↗

Cross-linking of fibrinogen and fibrin by fibrin-stablizing factor (factor XIIIa).

Factor XIIIa catalyzed intermolecular cross-linking of fibrinogen at initial rates that varied in direct (first order) proportion to the fibrinogen concentration, which differed from the well known zero order relationship in fibrin cross-linking. Preferential cross-linking of gamma-chains occurred with both substrates. The differences in rates and order of reaction were attributed mainly to effect of self-alignment of the gamma-chains in fibrin which enabled the cross-linking enzyme to interact with paired chains as a single rather than two independent entities. Studies on mixtures of fibrinogen and fibrin indicated factor XIIIa had near equal affinities for the two substrates. At low concentrations with which cross-linking of fibrinogen proceeded sluggishly compared to fibrin, fibrinogen inhibited stabilization of fibrin clots by competitively partitioning factor XIIIa away from the fribin. Additional inhibition arose from cross-linking of fibrin in soluble combination with fibrinogen in mixtures containing fibrinogen in large excess over fibrin. The observations demonstrate ways in which fibrinogen normally helps to suppress both polymerization and cross-linking of small amounts of fibrin produced within the circulation. At very high concentrations above 30 mg. per milliliter, fibrinogen underwent cross-linking at faster initial rates than the cross-linking of fibrin. Rapid cross-linking of concentrated fibrogen raises the possibility that filtration enrichment may be a factor contributing to abnormal formation of the highly insoluble fibrinogen deposits occurring in atheromatous tissue.

Animals↗

Renal subcellular fractions producing angionecrosis and increased vascular permeability.

In order to define the subcellular localization and characters of substances in the rat kidney which increase vascular permeability and produce angionecrosis, the following investigations have been undertaken: (1) subcellular fractionation by use of differential centrifugation and osmotic shock treatment with enzyme profile determination; (2) chromatographic separation of lysosomal contents with concanavalin A affinity column. Lysomal contents contained substances that induced an increase of vascular permeability of the rabbit skin and angionecrosis in the pancreas of the bilaterally nephrectomized rats and the spontaneously hypertensive rats. Lysosomal contents treated at 60 degrees for 30 min showed no renin activity and yet produced angionecrosis. Non-affinity fraction from concanavalin A column chromatography showed no renin activity but produced angionecrosis and an increase of vascular permeability of rabbit skin.

Acid Phosphatase↗

Cerebral atherosclerosis in Japanese. Part 4: relationship between lipid content and macroscopic severity of atherosclerosis.

In order to evaluate chemically the macroscopic scoring methods for severity of arteriosclerosis in the cerebral arteries, concentrations of total lipids, esterified and free cholesterol and lipid phosphorus were compared to the macroscopic severity of lesions in the cerebral arteries obtained from 376 Japanese persons after unexpected death. An increase of cholesterol content was correlated significantly with an increase of Baker's score and/or Gore's atherosclerotic index. The correlation coefficient between Baker's score and total or esterified cholesterol was the highest among the tested correlations (r = 0.82, n = 376).

Adult↗

A combination of cyclosporin-A (CsA) and interferon-gamma (INF-gamma) induces apoptosis in human gastric carcinoma cells.

Modulation of interferon-gamma effect by other drug may enhance its tumor specific activity. The apoptosis inducing effect of interferon-gamma and its modulation by cyclosporin-A or tacrolimus (FK-506) were investigated in in vitro and ex vivo experiments. We found that a combination of cyclosporin-A (CsA) and recombinant interferon-gamma (rIFN-gamma) induced significant apoptosis in all four types of human gastric carcinoma cells tested but not in normal cells such as human peripheral blood mononuclear cells (PBMCs), human omentum-derived mesothelial cells, or human umbilical vein endothelial cells (HUVECs) in vitro. Apoptosis was also induced by a combination of rIFN-gamma with FK-506 but not with rapamycin. Next, the apoptosis-inducing effect of endogenous IFN-gamma combined with cyclosporin-A was examined using clinical samples. A streptococcal preparation, OK-432, was administered intraperitoneally for the management of 12 gastric cancer patients with malignant ascites. None of the gascitic fluids obtained before the OK-432 injection showed detectable IFN-gamma level. The OK-432 injection induced a detectable IFN-gamma production ranging from 6 to 89 pg/mL in ascitic fluids from 9 out of the 12 patients. A combination of CsA with ascitic fluids collected after but not before OK-432 injection induced significant apoptosis in MK-1 cells, a gastric carcinoma cell line. A positive correlation was found between the IFN-gamma level and CsA-induced apoptosis. The CsA-induced apoptosis was also blocked by a specific antibody against human IFN-gamma. These results indicated that both recombinant and endogenous IFN-gamma can induce potent tumor-apoptosis when combined with CsA.

Adenocarcinoma↗