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Biomedical subjects

S Yuasa

Publications and source records attributed to S Yuasa.

At least 217 records · Page 12Linked to original sources
PubMed1979

Production of S-sulfocysteine from so-called cystine disulfoxide in the presence of aspartate aminotransferase.

S-Sulfocysteine production occurred when so-called cystine disulfoxide was incubated with aspartate aminotransferase and 2-oxoglutarate. Evidence was provided indicating that the alanine sulfinic acid portion of cystine disulfoxide was transaminated and the resulting sulfinylpyruvic acid portion decomposed non-enzymatically to give S-sulfocysteine and pyruvic acid.

Aspartate Aminotransferases↗
PubMed1978

Isolation and structure determination of a new amino acid, alpha-amino-gamma, delta-dihydroxyadipic acid, from the hydrolysate of normal human urine.

A new acidic amino acid has been isolated from the hydrolysate of normal human urine. The chemical structure of the amino acid was determined to be alpha-amino-gamma, delta-dihydroxyadipic acid, based on its physical properties involving nuclear magnetic resonance, infrared and mass spectrometry as well as chemical degradation and chemical synthesis.

2-Aminoadipic Acid↗
PubMed1978

A case of giant cavernous hemangioma of the liver complicated by intravascular coagulopathy.

A case of liver hemangioma complicated by intravascular coagulopathy is presented because of the rarity of the association. Hemangioma of the liver was suspected by palpation of the liver tumor, scintigraphy and x-ray examination, and confirmed by selective hepatic arteriography in combination with exploratory laparotomy. Intravascular coagulopathy was established by demonstrating secondary fibrinolysis and consumption of platelets and coagulation factors. Unconjugated hyperbilirubinemia due to micro-angiopathic hemolytic anemia was also present. The clinical course of the clotting abnormalities was basically a chronic one with an occasional acute or subacute defibrination process associated with further enlargement of the hepatic tumor. These provide sufficient evidence that the intravascular coagulopathy was closely related with the hemangioma in the liver. Neither ligation of a presumed nutritional artery of the hemangioma nor radiation therapy caused any demonstrable reduction in the tumor size.

Adult↗
PubMed1978

Purification and characterization of mitochondrial cysteine aminotransferase from rat liver.

Cysteine aminotransferase has been purified over 300-fold from rat liver mitochondria. Transamination between L-cysteine and 2-oxoglutarate, and the reverse reaction, were observed to be catalyzed by the purified enzyme but inhibited by L-aspartate. The enzyme also catalyzed transamination of alanine, 3-sulfinic acid, aspartic acid, and cysteic acid. A new reaction assay method was devised, contributing an indication that mitochondrial cysteine aminotransferase is identical to mitochondrial aspartate aminotransferase. The latter apparently catalyzed 3 transamination reactions in the cysteine degradation process within mitochondria.

Animals↗
PubMed1977

Evolutionary significance of the system utilizing D-amino acid enantiomers.

The evolutionary significance of the system utilizing D-amino acid enantiomers in living organisms is discussed, based on an experiment in which the mutant from Escherichia coli K--12 4627 grown on D-tryptophan was used. The mutant shows the ability of D-tryptophan is degraded to indol which can be utilized for the synthesis of L-tryptophan in the presence of serine.

Amino Acids↗
PubMed1977

Potassium activity and plasma membrane potentials in epithelial cells of toad bladder.

Intracellular potassium activity (aki), mucosal and serosal membrane potential (mEm, sEm), short-circuit current (Isc), and transepithelial potential difference in the epithelium of the toad bladder were measured with a potassium-sensitive liquid ion exchanger and an ordinary microelectrode. Under basal conditions, aki was 41.2 +/- 0.5 mM, corresponding to 54.4 mM in free potassium concentration, so half or more of the intracellular potassium may be of bound form or sequestrated within subcellular organelles. The sEm cannot be explained by only the potassium equilibrium potential (Eeq), because the sEm was markedly lower than the Eeq and no relation was found between them. Ouabain and rotenone decreased the aki, but ethacrynic acid, which also inhibited the Isc and the membrane potentials, did not show any effect on aki. Vasopressin decreased aki with an elevation in mEm, whereas prostaglandin E1 increased the aki with elevation in the sEm. These characteristic changes may afford an insight into the mechanisms by which transcellular electrolyte transport occurs.

Animals↗
PubMed1977

Desulfuration of l-cysteine through transamination and transsulfuration in rat liver.

Desulfuration of L-cysteine by rat liver via a pathway of transamination followed by transsulfuration was studied using cyanide as a sulfur acceptor. More than a 5-fold increase in formation of thiocyanate from L-cysteine and cyanide was observed in the presence of 2-oxoglutarate and pyruvate. L-Cysteine aminotransferase and 3-mercaptopyruvate sulfurtransferase activities in the same preparations were also determined. It was concluded that L-cysteine was desulfurated through transamination and transsulfuration of the resulting 3-mercaptopyruvate, and that the rate-limiting step appears to be the transamination reaction.

Animals↗
PubMed1976

Some international differences in treatment and survival in breast cancer.

In a recent study, 5-year survival rates for breast cancer patients in Boston (Massachusetts), Glamorgan (Wales), Slovenia (Yugoslavia) and Tokyo (Japan) were 57.3%, 49.5%, 41.9% and 74.9%, respectively. In this report, data are presented on the types of treatment used in the four areas and on the relationship of differences in treatment practices to the differences in survival rates. Generally, surgically treated patients who also had radiotherapy had lower survival rates than patients in the same area who had similar operations without radiotherapy. In each area, the survival rate was higher for patients who had radical mastectomy than for those who had simple mastectomy. The Japanese patients had the highest survival rate within nearly every treatment and extent-treatment category. Thus, the high survival rate of these patients was not explained by the variables considered. Survival differences between Boston, Glamorgan and Slovenia were largely explained by differences in extent of disease and type of treatment. As the nature of the treatment--survival trends was consistent with the interpretation that treatment tended to be selected according to apparent prognosis, the degree to which treatment customs were determinants of the differences in survival rate among the three areas is uncertain.

Boston↗
PubMed1975

Effect of colchicine on the osmotic water flow across the toad urinary bladder.

Osmotic water movement across the toad urinary bladder in response to both vasopressin and cyclic AMP was inhibited by 10(-5) to 10(-4) M colchicine on the serosal but not on the mucosal side. This inhibitory effect was found to be time- and dose-dependent. Colchicine alone did not change basal osmotic flow and a baseline of the short-circuit current (Isc) and also did not affect a vasopressin-induced rise of the Isc. The inhibitory effect was not prevented by the addition of pyruvate. The osmotic water movement produced by 360 mM Urea (mucosal), 360 mM mannitol (serosal) or 2 mug/ml amphotericin B (mucosal), was not affected by 10(-4) M colchicine. These results suggest that colchicine inhibits some biological process subsequent to the formation of cyclic AMP except a directional cytoplasmic streaming process where microtubules may be involved.

Amphotericin B↗
PubMed1975

A ten-year survey of bacteriuria in the Osaka university hospital.

10 consecutive years of observation of the laboratory data of quantitative urinary bacterial culture in the Central Clinical Laboratory of Osaka University Hospital was made. The marked rise of Pseudomonas and other Enterobacteriaceae was clearly demonstrated. The difference in bacterial species in bacteriuria between inpatients and outpatients strongly suggests that the origin of infection was quite different. The disappearance of Staph. aureus as a causative agent was also demonstrated.

Bacteriuria↗