Biomedical subjects

M Tsuboi

Publications and source records attributed to M Tsuboi.

At least 289 records · Page 16Linked to original sources

PubMed1976

Effect of 1-(m-chlorophenyl)-3-N,N-dimethyl-carbamoyl-5-methoxypyrazole (PZ-177) on drug-metabolizing enzyme on rat liver.

Effect of 1-(m-chlorphenyl)-3-N,N-dimethylcarbamoyl-5-methoxypyrazole (PZ-177) (62.5 and 250 mg/kg) on rat liver was investigated by measuring liver weight and drug-metabolizing enzyme activity. The effects of PZ-177 were compared with those of phenobarbital, phenylbutazone, and tiaramide hydrochloride. Increase of liver weight and liver/body weight ratio was observed in the rats treated with PZ-177 or phenobarbital, however, normal values were reverted to 1--2 weeks after treatment. PZ-177 similar to phenobarbital, significantly enhanced the activity of aminopyrine demethylase and aniline hydroxylase after 1,2, and 4 weeks of treatment. In contrast, tiaramide hydrochloride decreased the activity of aminopyrine demethylase and aniline hydroxylase after 1 week of treatment, and significantly enhanced the activity of these enzymes after 4 weeks. The content of cytochrome P-450 and the activity of NADPH cytochrome C reductase were also increased by treatment with PZ-177. The sleeping time by hexobarbital was shortened significantly by the administration of PZ-177. Vmax for both aminopyrine demethylase and aniline hydroxylase increased by treatment with PZ-177. However, only the Km for aniline hydroxylase was increased by treatment with PZ-177. From the results of these experiments, PZ-177 may be classified as a phenobarbital-type inducer.

Animals↗

PubMed1976

[Effects of K+ or norepinephrine on oxygen uptake in brown adipose tissue (author's transl)].

This investigation was undertaken to clarify the mechanism of the stimulated--respiration caused by K+ or norepinephrine in brown adipose tissue. 1. The addition of 30 approximately 100 mM K+ stimulated remarkably oxygen uptake in brown adipose tissue, and similarly norepinephrine (0.1 or 1.0 mug/ml) caused a marked stimulation. 2. Even if Na+ in normal Ringer solution was replaced by Choline or Li+, oxygen uptake caused by K+ (30 mM) or norepinephrine (1.0 mug/ml) was unaffected. 3. K+ -induced oxygen uptake was not observed when a Ca2+ -deficient tissue was incubated in Ca2+ -free Ringer, while norepinephrine-induced oxygen uptake clearly observed. And the oxygen uptake of Ca2+ -deficient tissue due to K+ was recovered by the addition of 5 mM Ca2+. 4. Mn2+ (6 mM) or La3+ (10 mM) inhibited significantly oxygen uptake due to K+, but not oxygen uptake due to norepinephrine. 5. K+ -induced oxygen uptake was unaffected by 10(-4) or 10(-3)M ouabain, but norepinephrine-induced oxygen uptake was inhibited considerably by 10(-4)M ouabain. 6. The oxygen uptake due to K+ was unaffected by propranolol (33 muM), whereas that due to norepinephrine was significantly inhibited in the presence of propranolol. 7. In the tissue from reserpine-treated animal, the oxygen uptake caused by K+ was observed. According, from these positive results we are justified to suggest that K+ -induced oxygen uptake is dependent on the presence of Ca2+, and not always caused by catecholamines released secondarily from nerve terminal.

Adipose Tissue, Brown↗

PubMed1975

Promotion of sporulation by caffeine pretreatment in Saccharomyces cerevisiae. I. Metabolism of nucleic acids and protein during sporulation.

Cells cultured in the presence of caffeine had high sporulation ability. The sporulation-promotive effect of caffeine was studied, special attention being paid upon changes in nucleic acid metabolism. When transferred to a sporulation medium, the breakdown of RNA, the synthesis of protein, RNA and DNA, commitment to sporulation and the appearance of mature asci took place in caffeine-treated cells significantly earlier than in control cells. Commitment to sporulation occurred before the completion of premeiotic DNA synthesis in both caffeine-treated and control cells.

Caffeine↗

PubMed1975

Comparative studies on sporulation-promotive actions on cyclic AMP, theophylline and caffeine in Saccharomyces cerevisiae.

Cyclic AMP, theophylline and caffeine promoted sporulation when added to a presporulation medium containing glucose. Caffeine promoted sporulation even when added to a presporulation medium containing acetate as the carbon source, but cyclic AMP and theophylline did not. Caffeine did not increase the intracellular cyclic AMP level, while theophylline did significantly when added to a presporulation medium containing glucose. Caffeine inhibited the vegatative DNA synthesis with little effect on RNA and protein synthesis, resulting in the increase in cell volume, dry weight, and RNA and protein contents, but cyclic AMP and theophylline did not show such effects.

Acetates↗

PubMed1975

Electron microscopic and electron histochemical studies on embryonal rhabdomyosarcoma of the orbit.

A small number of differentiated tumor cells could be found besides a great number of undifferentiated ones. Abnormal dense granules were found in the nuclei of undifferentiated tumor cells, not in differentiated ones. Non-specific filaments were seen in the cytoplasm of undifferentiated tumor cells. Differentiated tumor cells demonstrated various stages of myofibrillar structures such as A, I, and Z bands, many glycogen granules, mitochondria and a basement membrane. Polyglucose particles synthesized from glycose-1-phosphate by phosphorylase activity were located in the cytoplasmic matrix of undifferentiated and differentiated tumor cells and in the karyolymph of undifferentiated tumor cells. Polyglucose partices increased in number according to the degree of differentiation of tumor cells.

Basement Membrane↗

PubMed1975