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Biomedical subjects

K Matoba

Publications and source records attributed to K Matoba.

At least 37 records · Page 2Linked to original sources
PubMed1988

Role of calcium in suppression of glucagon release from isolated diabetic rat pancreata.

To investigate the role of extracellular Ca2+ (Ca2+) in suppression of glucagon release in diabetic animals, pancreata were isolated from streptozotocin-diabetic rats and perfused with a 15 mM glucose solution containing one of the following: (1) Ca2+ 2.1 mM and insulin 22 microU/ml, (2) Ca2+ 2.1 mM and insulin 110 microU/ml, (3) Ca2+ 2.1 mM and insulin (-) or (4) Ca2+ 0.2 mM and insulin 110 microU/ml. Although perfusion with 22 microU/ml of insulin did not alter glucagon release, perfusion with 110 microU/ml of insulin in the presence of Ca2+ and glucose significantly reduced the release of glucagon from 1.9 +/- 0.3 ng/min to 1.2 +/- 0.3 ng/min for the first 3 min. The absence of insulin enhanced glucagon release from the baseline level of 1.0 +/- 0.1 ng/min to 1.6 +/- 0.3 ng/min at 11 min and to 1.4 +/- 0.2 ng/min at 21 min. Deprivation of Ca2+ in the perfusate also enhanced glucagon release from the baseline level of 0.8 +/- 0.1 ng/min to 1.2 +/- 0.3 ng/min for the first 4 min. It is concluded that insulin suppresses glucagon release and Ca2+ is needed for the suppression of glucagon release in the presence of both insulin and glucose in streptozotocin-diabetic rat pancreata.

Animals↗
PubMed1982

Identity of alpha-glucosidase of human kidney with urine F-1 alpha-glucosidase.

alpha-Glucosidase was extracted from a homogenate of human kidney, initially with 0.02 M Tris-HCl buffer, pH 7.6, and subsequently with a mixture of 0.5% cholate and 0.5% Triton X-100 in the same buffer, pH 7.6. The enzyme in each of these two fractions was purified to the electrophoretically pure state by fractional precipitation with ammonium sulfate, column chromatographies on DEAE-cellulose, hydroxyapatite, Bio Gel A-1.5 m and affinity chromatography on heated glutinous rice. The two purified alpha-glucosidase preparations obtained were the same in enzymatic and proteochemical properties, and the molecular weight and isoelectric point estimated were 3 x 10(5) and 4.2, respectively. No evidence for subunit structure was obtained. The optimum pH for activity was 5.6 and the activity was drastically inhibited by Nojirimycin. The alpha-glucosidase readily hydrolyzed maltose, starch, and glycogen, producing only glucose. It hydrolyzed maltotriitol to split the non-reducing end glucose, but scarcely hydrolyzed maltitol or various other heteroglucosides examined. All these proteochemical and enzymatic properties of kidney alpha-glucosidase were the same as those of urine F-1 alpha-glucosidase. Also, kidney tissue alpha-glucosidase produced a clear precipitin line with antisera against urine F-1 alpha-glucosidase. These facts suggest that F-1 alpha-glucosidase in urine originates from kidney tissue.

Glucosidases↗
PubMed1982

On the origin of alpha-glucosidase in human urine.

The recent findings that alpha-glucosidase from human kidney was identical with one component (F1) of the alpha-glucosidases found in human urine suggested the idea that this enzyme might originate in the kidneys. The present study was performed to test this idea by immunological methods. Urine alpha-glucosidase F1 was isolated in the electrophoretically homogeneous state, and the antibody prepared in rabbits was purified by affinity chromatography after the antisera were fractionally precipitated with ammonium sulfate and chromatographed on diethylamino ethyl (DEAE)-cellulose. The staining of human kidney tissue sections was performed by the indirect method, using alpha-glucosidase F1 antibody and fluorescein-conjugated anti-rabbit immunoglobulin goat sera. The proximal convoluted portion (proximal tubules) with brush border and Henle's loops (late proximal) were stained clearly. Preincubation of intact antibody with purified antigen prevented specific staining of the proximal convoluted portion and Henle's loops. In contrast, all other tissues of kidney were stained less positively or negatively. These results indicate that alpha-glucosidase F1 originates in the kidney, and that glucosidase is specifically localized in the proximal convoluted portion and Henle's loops.

Adult↗
PubMed1980

Clinical study of niceritrol on serum lipids in the treatment of hyperlipidemia.

The effects of niceritrol, a nicotinic acid derivative, on the levels of HDL-cholesterol (HDL-Ch) and a mixture of VLDL- and LDL-Ch (VLDL- + LDL-Ch) were studied in hyperlipidemic patients. Serum total cholesterol (sTC) and serum triglyceride (sTG) were significantly reduced during niceritrol administration. Lipoprotein electrophoresis showed that niceritrol increased the alpha:beta ratio. HDL-Ch showed a significant increase of 12.5% by the 16th week of therapy. This increase was more marked in patients with lower pre-treatment HDL-Ch levels and significant in patients whose pre-treatment sTG levels were in excess of 200 mg/dl. Females displayed higher pre-treatment HDL-Ch levels (38.5 mg/dl) than males (30.6 mg/dl). However, niceritrol increased HDL-Ch significantly in both groups. At 16 weeks, the VLDL- + LDL-Ch level showed a significant decrease of 9.2%; the HDL-Ch:VLDL + LDL-Ch and HDL-CH:sTC ratios were significantly increased throughout niceritrol administration. Niceritrol is thought to be effective in preventing the development and progression of atherosclerosis because it raises the level of anti-atherogenic HDL-Ch and lowers the level of atherogenic VLDL- + LDL-Ch.

Cholesterol↗