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Biomedical subjects

T Tsuchiya

Publications and source records attributed to T Tsuchiya.

At least 847 records · Page 47Linked to original sources
PubMed1977

Effects of benzodiazepines on PGO firings and multiple unit activity in the midbrain reticular formation in cats.

Effects of benzodiapines administered by the intraperitoneal route on PGO firings and multiple unit activity in the midbrain reticular formation in chronic cat preparations were investigated at various levels of consciousness. Changes in the sleep-wakefulness cycle induced by direct injection of benzodiazepines into the reticular formation were also investigated. Benzodiazepines markedly decreased multiple unit activity in the midbrain reticular formation during each stage of sleep, but had little effect during behavioral and EEG arousal. Benzodiazepines did not affect PGO firing rate, but attenuated all increase of multiple unit activity following PGO firings. The bilateral injection of benzodiazepines into the midbrain reticular formation induced an increase of arousal and a decrease of slow wave sleep, but did not change the amount of paradoxical sleep. It is concluded that benzodiazepines show a mixture of depressant and facilitatory effects, which seem to vary with the state of consciousness of the animal.

Animals↗
PubMed1977

Adenosine 5'-triphosphate synthesis driven by a protonmotive force in membrane vesicles of Escherichia coli.

Adenosine 5'-triphosphate (ATP) synthesis energized by an artificially imposed protonmotive force (delta p) in adenosine 5'-diphosphate-loaded membrane vesicles of Escherichia coli was investigated. The protonmotive force is composed of an artificially imposed pH gradient (delta pH) or membrane potential (deltapsi), or both. A delta pH was established by a rapid alteration of the pH of the assay medium. A delta psi was created by the establishment of diffusion potential of K+ in the presence of valinomycin. The maximal amount of ATP synthesized was 0.4 to 0.5 nmol/mg of membrane protein when energized by a delta pH and 0.2 to 0.3 nmol/mg of membrane protein when a delta psi was imposed. Simultaneous imposition of both a delta pH and delta psi resulted in the formation of greater amounts of ATP (0.8 nmol/mg of membrane protein) than with either alone. The amount of ATP synthesized was roughly proportional to the magnitude of the artificially imposed delta p. Although p-chloromercuribenzoate, 2-heptyl-4-hydroxyquinoline-N-oxide, or NaCN each inhibits oxidation of D-lactate, and thus oxidative phosphorylation, none inhibited ATP synthesis driven by an artificially imposed delta p. Membrane vesicles prepared from uncA or uncB strains, which are defective in oxidative phosphorylation, likewise were unable to catalyze ATP synthesis when energy was supplied by an artificially imposed delta p.

Adenosine Triphosphate↗
PubMed1977

Glutamate transport driven by an electrochemical gradient of sodium ions in Escherichia coli.

The role of Na+ in glutamate transport was studied in Escherichia coli B, strain 29-78, which possesses a very high activity of glutamate transport (L. Frank and I. Hopkins, J. Bacteriol., 1969). Energy-depleted cells were exposed to radioactive glutamate in the presence of a sodium gradient, a membrane potential, or both. One hundred- to 200-fold accumulation of the amino acid was attained in the presence of both electrical and chemical driving forces for the sodium ion. Somewhat lower accumulation values were obtained when either chemical or electrical driving forces were applied separately. A chemical driving force was produced by the addition of external Na+ to Na+-free cells. A membrane potential was established by a diffusion potential either of H+ in the presence of carbonyl cyanide p-trifluoromethoxyphenylhydrazone or of SCN-. These results support the hypothesis of a Na+-glutamate cotransport. Na+-driven glutamate transport was also observed in wild-type E. coli B but not in a strain of K-12.

Biological Transport, Active↗
PubMed1977

[Effects of 5-(o-chlorophenyl)-1-methyl-7-nitro-1, 3-dihydro-2HO1, 4-benzodiazepin-2-one (ID-390) as compared to nitrazepam on the sleep-wakefulness cycle in cats (author's transl)].

ID-690 was given at doses over 0.3 mg/kg, and increase in state of arousal and decrease in state of slow wave sleep were observed. Nitrazepam at doses over 1.0 mg/kg revealed similar effects. These agents increased incidences of paradoxical sleep at a low dose of 0.03 mg/kg. When ID-690 was given at doses over 0.3 mg/kg, the number and duration of incidences of paradoxical sleep decreased. Nitrazepam at doses over 0.1 mg/kg had a similar depressive effect on paradoxical sleep. These results suggest that these benzodiazepines have, dose-dependently, both facilitative and depressive actions on paradoxical sleep, and that the dose of these agents which affects arousal is not always the same as that which affects paradoxical sleep.

Animals↗
PubMed1977

Syntheses of 6'-C-aminomethyl-3'-deoxyparomamines.

The first synthesis of 6'-C-aminomethyl derivatives (6'-epimers) of 3'-deoxyparomamine is reported starting from 3'-deoxyparomamine by way of 6'-O-tritylation, O-acetylation, hydrolysis of the trityl group, conversion of the 6'-hydroxyl group into an aldehyde group, nitromethane condensation of the aldehyde group and catalytic reduction of the nitro group into an amino group.

Acetylation↗
PubMed1976

Oxidative phosphorylation in right-side-out membrane vesicles from Escherichia coli.

Oxidative phosphorylation in Escherichia coli membrane vesicles with a right-side-out orientation and loaded with ADP was investigated. Substrates of the electron transport chain could energize the phosphorylation of ADP, with the order of effectiveness being D-lactate greater than reduced phenazinemethosulfate greater than succinate greater than reduced nicotinamide adenine dinucleotide. Inhibitors of D-lactate oxidation, proton conductors, and inhibitor of the Mg2+ATPase (EC 3.6.1.3) all inhibited oxidative phosphorylation when coupled to D-lactate oxidation. ATP synthesis was absent in membrane vesicles prepared from a mutant strain lacking the Mg2+ATPase. Valinomycin or nigericin partially inhibited oxidative phosphorylation in the presence of potassium. Valinomycin plus nigericin completely inhibited ATP synthesis. The effect of various agents on the respiration-dependent establishment of a transmembrane pH gradient was also examined. NaCN and carbonyl cyanide p-trifluoromethoxyphenylhydrazone inhibited the establishment of a pH gradient while dicyclohexylcarbodiimide had no effect. These results are in good agreement with a chemiosmotic model for oxidative phosphorylation.

Arsenates↗
PubMed1976

Calcium transport driven by a proton gradient and inverted membrane vesicles of Escherichia coli.

Calcium transport into inverted vesicles of Escherichia coli was observed to occur without an exogenous energy source when an artificial proton gradient was used. The orientation of the proton gradient was acid inside and alkaline outside. Either phosphate or oxalate was necessary for transport, as was found for respiratory-driven or ATP-driven uptake (Tsuchiya, T., and Rosen, B.P. (1975) J. Biol. Chem. 250, 7687-7692). Phosphate accumulation was found to occur in conjunction with calcium accumulation. Calcium transport driven by an artificial proton gradient was stimulated by dicyclohexylcarbodiimide, an inhibitor of the Mg2+ATPase (EC 3.6.1.3). Valinomycin, which catalyzes electrogenic potassium movement, stimulated calcium accumulation, while nigericin, which catalyzes electroneutral exchange of potassium and protons, inhibited both artificial proton gradient-driven transport and respiratory-driven transport. Other properties of the proton gradient-driven system and the previously reported energy-linked calcium transport system are similar, indicating that calcium is transported by the same carrier whether energy is supplied through an artificial proton gradient or an energized membrane state. These results suggest the existence of a calcium/proton antiport.

Biological Transport, Active↗
PubMed1976

A synthesis of 3',4'-dideoxykanamycin B.

3',4',-Dideoxykanamycin B, the kanamycin B derivative that is active against resistant bacteria, was prepared from kanamycin B via N-tosylation, 3',4'-O-sulphonylation, 3',4'-unsaturation, and hydrogenation. The unsaturated intermediate was obtained from the 3',4'-di-O-sulphonyl derivatives by the action of sodium iodide in N,N-dimethylformamide; if zinc dust was added in this reaction, aziridine derivatives were formed. Removal of the tosyl group was successfully performed by using sodium in ammonia-ethylamine.

Dibekacin↗
PubMed1976

Serological relationships among some Pichia species.

Antigenic analyses of five species of the genus Pichia were carried out for taxonomic study by the slide agglutination method using monospecific and absorbed antisera and the agglutinin absorption technique. Comparative studies were also performed with a few strains of each of the same species and their classifications are discussed with respect to the antigenic structures and the patterns of proton magnetic resonance (PMR) spectra of their cell wall polysaccharides. ichia delftensis and Pichia zaruensis possessed thermostable antigens 1,2,5 and 11, and the former had also thermoabile antigen m. Both species were closely related to Candida krusei. Pichia toletana possessed thermostable antigens 1,2,5,11,17 and 49. Pichia bovis contained thermostable antigens 1,2,14,15,16,20 and 21, and it was related to most species of the genus Hansenula, although assimilation of potassium nitrate was negative. Finally, Pichia etchellsii possessed thermostable antigens 1,2,3,4,9 and 14, and was closely related to Pichia vini. Patterns of PMR spectra of mannans of these species also supported their serological relationships. Therfore, P. delftensis, P. zaruensis and P. etchellsii are considered to be the synonyms of Pichia fluxuum, Pichia dispora and P. vini respectively, although P. toletanan and P. bovis are independent species.

Antigens, Fungal↗