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Biomedical subjects

H Yamanaka

Publications and source records attributed to H Yamanaka.

At least 19 recordsLinked to original sources
PubMed1979

Mutagens in coffee and tea.

Coffee prepared in the usual way for drinking contains a substance(s) that is mutagenic to Salmonella typhimurium TA100 without mammalian microsomal enzymes. One cup of coffee (200 ml) contains mutagen(s) inducing 1.4-4.6 X 10(5) revertants under standard conditions. Instant coffee too is mutagenic to TA100 and one cup of instant coffee prepared from 1 g of coffee powder and 200 ml of water induced 5.6-5.8 X 10(4) revertants of TA100. Caffeine-free instant coffee also has similar mutagenicity. Addition of microsomal enzymes abolished the mutagenicity. Black tea, green tea and Japanese roasted tea were also mutagenic to TA100 without S9 mix and one cup of these teas prepared in the ordinary way produced 1.7-3.8 X 10(4) revertants of TA100. Black tea and green tea were also mutagenic to TA98 in the presence of S9 mix after treatment with a glycosidase from Aspergillus niger, hesperidinase. This type of mutagen in one cup of black tea induced 2.4 X 10(5) revertants of TA98.

Coffee↗
PubMed1979

Mutagenicity of pyrrolizidine alkaloids in the Salmonella/mammalian-microsome test.

The mutagenicities of 7 pyrrolizidine alkaloids to Salmonella typhimurium TA100 were demonstrated by a modified Ames's method. The pyrrolizidine alkaloids found to be mutagenic were clivorine, fukinotoxin, heliotrine, lasiocarpine, ligularidine, LX201 and senkirkine. Pre-incubation of these alkaloids with S9 mix and bacteria in a liquid medium was essential for demonstration of their mutagenicities.

Animals↗
PubMed1979

Effects of antiprostatic agents on 5alpha-dihydrotestosterone binding to rat hypophyseal and hypothalamic cytosol macromolecules.

The binding of 5alpha-dihydrotestosterone to the hypophyseal and hypothalamic cytosol macromolecules prepared from castrated male rats was observed. The effects of antiprostatic agents on 5alpha-dihydrotestosterone binding to both hypophyseal and hypothalamic cytosol macromolecules was examined. Cyproterone acetate and chlormadionone acetate showed the significant inhibiting effects on 5alpha-dihydrotestosterone binding to 7-8 S macromolecules of cytosol from both hypophysis and hypothalamus. SCH 13521 and AA 560 did also affect 5alpha-dihydrotestosterone binding to 7-8 S macromolecules of cytosol from both tissues.

Androgen Antagonists↗
PubMed1979

Isolation of Selenomonas spp. from lesions and non-digestive organs of cows, pigs and man.

Selenomonas spp. were isolated for the first time from lesions and non-digestive organs which were apparently normal in 2 cows, 6 pigs, and 1 human being. Identification as Selenomonas was based firstly on electron microscopical observation and secondly on fermentation products. They were divided into 3 major groups by biological properties, as well as by the patterns of these products. It has been confirmed that the habitats of organisms of the genus Selenomonas are generally digestive organs, including the rumen of the ruminant, the cecum of the guinea pig, and the oral cavity of man. The existence of these organisms in lesions and non-digestive organs in such animals and man, however, has been unknown as yet. Moreover, it has been completely unknown about the habitat of these organisms in swine. The findings obtained suggested the possibility of invasion of Selenomonas into other parts than the digestive organ in some animals and the presumable existence of the organism in the swine digestive organs. The role of Selenomonas as a secondary invader into some animals was proposed.

Animals↗
PubMed1978

Requirement of calcium ions for cell degeneration with a toxin (vibriolysin) from Vibrio parahaemolyticus.

A highly purified toxin (vibriolysin) from Vibrio parahaemolyticus caused degeneration of cell shape, such as bleb and balloon formation, of mouse myocardial cells and mouse melanoma cells in culture. An extracellular Ca2+ concentration of more than 10(-6) M was necessary for the degeneration of cell shape, but extracellular Mg2+, Na+, and K+ were not necessary. In the presence of extracellular Ca2+, vibriolysin also caused full contraction of myofibrils of mouse myocardial cells and reduction of both actin cables and tubulin networks of mouse melanoma cells. Vibriolysin also caused excess uptake of Ca2+ from the incubation medium by mouse myocardial cells and mouse melanoma cells. Chick myocardial cells, which show neither degeneration of cell shape nor full contraction of myofibrils, did not take up excess 45Ca2+ in the presence of vibriolysin. These findings suggest that the vibriolysin-induced degeneration of cell shape of mouse myocardial cells and mouse melanoma cells is due to excess uptake of Ca2+ from the incubation medium by the cells.

Bacterial Toxins↗
PubMed1977

Bovine like-sexed male twins with chromosomal chimerism.

Sex-chromosomal chimerism (XX/XY) was described in a pair of bovine like-sexed male twins. One of the twins showed malformed external genitalia, and the other was phenotypically normal. It is proposed that sex-chromosomal chimerism is associated with a choriovascular anastomosis between like-sexed twins examined and "female fetus" which may be overlooked at parturition.

Animals↗
PubMed1977

Effect of hypolipidemia on testosterone-stimulated prostatic growth in castrated rats.

Hypolipidemia caused by Simfibrate feeding for 3 weeks reduced responses of weight and nucleic acid contents to testosterone administration in the ventral and dorsolateral prostates of castrated rats. However, the effect of testosterone on the contents of citrate, fructose, zinc and the activity of testosterone 5alpha-reductase in the glands of castrated animals was not modified by Simfibrate feeding.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗