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Biomedical subjects

T Mitamura

Publications and source records attributed to T Mitamura.

At least 73 records · Page 4Linked to original sources
PubMed1982

Separation of cholesterol-induced high density lipoproteins (HDLc) by concanavalin A-Sepharose affinity chromatography.

Cholesterol-induced density lipoprotein(s), termed HDLc, is one of the abnormal lipoproteins which occur in experimental hypercholesterolemia in several animal species, including rats. Thus far, HDLc has been exclusively isolated by sequential ultracentrifugation followed by Geon-Pevikon block electrophoresis, which is time-consuming and requires some specialized knowledge. In this report, a faster and more convenient alternative method for the isolation of HDLc is described. A combination of a single ultracentrifugation and agarose gel chromatography followed by concanavalin A-Sepharose affinity chromatography was employed. HDLc thus obtained was similar to and probably identical with the HDLc isolated by Geon-Pevikon electrophoresis, with respect to chemical composition, electrophoretic properties in agarose gel, apoprotein patterns in SDS polyacrylamide gel electrophoresis, and electron micrographic appearance.

Animals↗
PubMed1981

Malignant degeneration of benign cystic teratomas of the ovary.

In 10 years from January 1971 to January 1981, 145 cases with cystic teratoma were treated at Kurume University Hospital, and malignant degeneration was seen in 7 of them (4.8%). Their age distribution was from 43 to 78 years, and the mean age was 59 years; the distribution shifted to the older side. The malignant degeneration was squamous cell carcinoma in all of the cases, and in 1 case carcinoma in situ leads to invasive carcinoma was observed continuously to a normal epithelium; it was interesting histogenetically. In their prognoses 3 out of 7 cases died (1 case dying from decrepitude) but the rest 4 have been surviving for 4 to 10 years.

Adult↗
PubMed1979

Alterations of high density lipoproteins in experimental cholestasis in the rat.

High density lipoproteins (HDL) in the plasma from cholestatic rats were studied by gel filtration, polyacrylamide gel electrophoresis and electron microscopy. HDL from cholestatic rats separated into two subfractions, abnormally enlarged particles and smaller ones, on gel filtration through Bio-Gel A 1.5 m. Polyacrylamide gel electrophoresis in 8 M urea revealed that the relative proportion of C-III-3 peptide in C-apoproteins was higher in the two HDL subfractions from cholestatic rats than in normal HDL. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate showed that the abnormally enlarged HDL contained the 'arginine-rich' apoprotein, whereas a band corresponding to 'arginine-rich' apoprotein was only faintly visible in the smaller HDL subfraction. Normal HDL contained much smaller amount 'arginine-rich' apoprotein than the enlarged HDL. In electron microscopy, both of the two subfractions of cholestatic HDL appeared spherical. The abnormally enlarged HDL were consisted of particles with a diameter of 17 +/- 4.5 nm (mean +/- S.D.). The other subfraction contained smaller particles with a diameter (about 10 nm) similar to normal HDL.

Animals↗
PubMed1977

[The interaction of Ca2+ and heparin in the activation of lipoprotein lipase from adipose tissue (author's transl)].

The effect of calcium on the activation of lipoprotein lipase by heparin was studied using ammonia buffer extracts of acetone powder from guinea pig adipose tissue as the lipoprotein lipase source. Lipase activity was assayed with an artificial triglyceride emulsion that had been activated with rat high density lipoproteins. The addition of Ca2+ (2mM) alone increased the lipoprotein lipase activity about 2.5- to 3.5-fold, but heparin (1 unit/ml) alone had little effect. When both Ca2+ and heparin were added to the assay medium, the activity was increased to 4- to 5- fold above control values. When Ca2+ in the assay medium was sequestrated by EGTA, these increases by Ca2+ and heparin were completely abolished. The results suggest that the presence of Ca2+ is a prerequisite for the activation of lipoprotein lipase by heparin. Gel filtration of the mixture of acetone poder extracts and [3H] heparin showed the enzyme bound [3H] heparin whether Ca2+ was present or not. In addition to lipoprotein lipase, there were proteins in adipose tissue extracts which had an affinity for heparin.

Adipose Tissue↗
PubMed1976

A case of gouty arthritis associated with Down's syndrome.

Gouty arthritis developed in a twenty-one-year-old male whose karyotyping showed Trisomy 21. His serum urate level was 13.1 mg per 100 ml and his twenty-four-hour urinary uric acid excretion was 431 mg on a low purine diet. Uric acid clearance was decreased to 3.9 ml per minute. The cumulative incorporation of N15-glycine into urinary uric acid during successive seven days was 0.144 per cent, which was within the normal range. Diminished uric acid clearance may be attributed to this hyperuricaemia. The cause of gouty arthritis and Down's syndrome in the patient is discussed.

Adult↗
PubMedDate not supplied

Protective effects of an antiulcer agent, ecabet sodium on colorectal carcinogenesis in rodents.

A new antiulcer agent, ecabet sodium is one of dehydroabietic acid derivatives prepared from pine resin. The effects of ecabet sodium on colorectal carcinogenesis were investigated in azoxymethane-pretreated mice with chronic ulcerative colitis induced by 3 repeated administration of 3% dextran sulfate sodium and in 1, 2-dimethylhydrazine-treated rats. Although daily treatment with ecabet sodium did not affect the colorectal DNA-synthesizing enzyme activities and bromodeoxyuridine-immunoreactive S-phase cells, high-grade dysplasia in ecabet sodium-treated mice was less frequent than in untreated mice. In rats, ecabet sodium administration reduced the elevated activity of thymidylate synthetase in colorectal tumors.

1,2-Dimethylhydrazine↗
PubMedDate not supplied

Correlation between histological differentiation and DNA-synthesizing enzymes in rat colorectal tumors induced with 1, 2-dimethylhydrazine.

Thymidylate synthase and thymidine kinase are key enzymes involved in de novo and salvage pathways for pyrimidine nucleotide synthesis. Colorectal carcinogenesis induced with 1,2-dimethylhydrazine in rats enhanced mRNA expression levels of both enzymes, resulting in the increase of both enzyme activities and bromodeoxyuridine-immunoreactive S-phase cells. Poorly and well differentiated adenocarcinomas of the colorectum showed the relative elevation of activities of thymidylate synthase and thymidine kinase, respectively. These results indicate that the relationship between de novo and salvage pathways for pyrimidine nucleotide synthesis may depend on the histopathological grades of cell differentiation.

Animals↗