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Biomedical subjects

K Miyata

Publications and source records attributed to K Miyata.

At least 397 records · Page 22Linked to original sources
PubMed1983

Cinoxacin: competitive inhibitory effect on p-aminohippurate transport and its uptake in renal cortical slices.

The effect of cinoxacin on p-aminohippurate (PAH) transport and the accumulation of cinoxacin were examined in renal cortical slices. Cinoxacin significantly inhibited the uptake of PAH by the slices from rats and rabbits. Cinoxacin increased the apparent Michaelis constant (Km) but did not affect Vmax for PAH uptake by rat kidney cortical slices, suggesting that cinoxacin inhibited PAH transport in a competitive manner. Cinoxacin was taken up but did not affect the cellular metabolism of Na+, K+ and ATP in the slices from rats and rabbits, except that 740 microM cinoxacin increased net Na+ efflux. These data indicate that cinoxacin is transported by the same process as that of PAH in renal cortical slices. Lastly, repeated administration of cinoxacin to rats did not affect the uptake of the drug by the slices.

Adenosine Triphosphate↗
PubMed1982

Circulating immune complexes in rheumatic fever.

We measured the circulating immune complex levels in patients with rheumatic fever using the following three methods: the C1q binding test, the conglutinin binding test and Raji cell radioimmunoassay. Thirty-four samples from 21 patients with rheumatic fever were examined, and circulating immune complexes were detected in 47.6% of the patients by one or more of these methods. Especially by the C1q binding test, the sera obtained in the acute phase were found to contain the circulating immune complexes with higher frequency than those obtained in the post-acute phase. Therefore, the C1q binding test was more likely to be useful in the acute phase of this disease. The present study suggests that the circulating immune complexes are related to the pathogenesis of rheumatic fever.

Adolescent↗
PubMed1981

Elastic fibers associated with collagenous fibrils surrounded by reticular cells in lymph nodes of the rat as revealed by electron microscopy after orcein staining.

Electron microscopy of the rat lymph node disclosed reticular cells in close association with bundles of collagenous fibrils 30-45 nm in diameter, and electron lucent "amorphous" substances surrounded by microfibrils 11 nm in diameter, with junctional complexes. The amorphous substances, distinctly revealed by orcein staining, and the microfibrils showed morphological characteristics of elastic fibers. Since elastase digestion of 2% glutaraldehyde fixed specimens induced the selective disappearance of the orcein-stainable substances, it was concluded that they are elastin. Elastin often had a close contact with the plasma membrane of reticular cells. It is suggested that reticular cells synthesize elastic fibers.

Animals↗
PubMed1981

Cytotoxicity of antiserum sensitized hemolytic streptococcal M protein fraction on cultured myocardial cells.

We have studied cytotoxicity of antisera of monkeys sensitized to streptococcal M protein fraction, which was prepared by the method of Lancefield et al., on cultured myocardial cells. These antisera exerted a significantly higher cytotoxic effect on the myocardial cells than normal monkey sera, and this cytotoxic effect seemed to be organ-specific. In the presence of normal monkey lymphocytes, the antisera had a cytotoxic effect on myocardial cells, but normal sera in the presence of normal monkey lymphocytes had no cytotoxic effects. These data suggest that M protein fraction of hemolytic streptococcus plays an important role in the pathogenesis of rheumatic carditis.

Animals↗
PubMed1981

Interaction between Serratia protease and human plasma alpha 2 macroglobulin.

Serratia protease (TSP) [EC 3.4.24] was bound stoichiometrically to alpha 2 macroglobulin (alpha 2M), which was purified and crystallized from human plasma, but apo TSP was not bound. On formation of the TSP-alpha 2M complex the enzymatic activity of the bound TSP was affected with respect to substrates; Km values of the bound TSP were unchanged but Vmax values were reduced. alpha 2M was cleft at the mid-region of its subunits chains by TSP, which resulted in a conformational change of the alpha 2M molecule with TSP.

Electrophoresis, Polyacrylamide Gel↗
PubMed1980

Stimulation of glycosaminoglycan sulfotransferase from chick embryo cartilage by basic proteins and polyamines.

A soluble glycosaminoglycan sulfotransferase (3'-phosphoadenylylsulfate:chondroitin 4'-sulfotransferase, EC 2.8.2.5) from chick embryo cartilage has been prepared free from endogenous acceptor. The reaction with this enzyme preparation was stimulated by basic proteins and polyamines, the degree of stimulation being dependent on the chemical nature of both basic compounds and acceptor glycosaminoglycans. A maximum stimulation was obtained when protamine (basic compound) and chondroitin (acceptor) were involved in the reaction mixture at a molar ratio of protamine to repeating disaccharide units of chondroitin, 1:100. The stimulation of sulfotransferase activity by basic substances was much higher than that by Mn2+. However, increasing the Mn2+ concentration immediately reduced the stimulation by basic substances. The Km value for 3'-phosphoadenosine 5'-phosphosulfate of the sulfotransferase, when chondroitin was used as acceptor, was 1 . 10(-6) M in the presence of 25 microgram/ml protamine, compared to 2 . 10(-5) M in the absence of protamine. These observations indicate that the basic proteins and polyamines may interact with acceptor polysaccharide, thereby causing an increase in the affinity of the enzyme toward 3'-phosphoadenosine 5'-phosphosulfate.

Animals↗
PubMed1980

Effects of strong electrolytes on the iron alum--Alcian Blue--Safranin staining of mast cell granules of the rat.

Rat mast cells fixed in Carnoy's fluid were stained with iron alum-Alcian Blue--Safranin solution after pre-treatment with strong electrolyte solutions including acids, neutral salts and alkalis. Although both red and blue mast cells were observed without pre-treatment, most mast cells were stained blue and a few red when they were stained after the pre-treatment. Mast cell granules contain salt complexes formed between basic proteins and acidic polysaccharides through ionic linkages between protein basic groups and polysaccharide sulphate and carboxylic acid groups. It is suggested that when sections are treated with strong electrolyte solutions, complexes are broken by disruption of ionic linkages and sulphate and carboxylic acid groups of polysaccharides masked by basic proteins become available for binding Alcian Blue. This was confirmed by model experiments performed with smears of a heparin-lysozyme complex. When mast cells were fixed in aldehyde-containing fixatives, no effects of strong electrolyte solutions on the staining properties of mast cell granules were revealed.

Alcian Blue↗