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Biomedical subjects

Y Noguchi

Publications and source records attributed to Y Noguchi.

At least 469 records · Page 26Linked to original sources
PubMed1981

Potassium stimulated 45Ca uptake by cortical slices of rat brain: effects of cyclic nucleotide derivatives.

The effects of dibutyryl cyclic GMP (db-cGMP) and dibutyryl cyclic AMP (db-cAMP) on potassium-stimulated 45Ca uptake by cortical slices of rat brain were investigated. db-cGMP specifically inhibited the initial rate of potassium-stimulated 45Ca uptake in a dose-dependent manner. Our findings supported the suggestion that cyclic GMP may play a regulatory role in depolarization-elicited Ca2+ influx in nerve endings in situ.

Animals↗
PubMed1980

Effects of dopaminergic agonists and antagonists on [3H]apomorphine binding to striatal membranes: sulpiride lack of interactions with positive cooperative [3H]apomorphine binding.

Effects of dopaminergic agonists and antagonists on [3H]apomorphine binding to striatal membranes of rat brain was examined. Haloperidol and spiroperidol exhibited biphasic inhibition of [3H]apomorphine binding; one of which had the Hill coefficient of 0.9, whereas the other had that of 0.4. The former accounted for 65% of [3H]apomorphine binding while the latter consisted of 35% of the binding. Furthermore, the latter disappeared after kainic acid lesions. On the other hand, sulpiride and metoclopramide reduced [3H]apomorphine binding to 31% with the Hill coefficient of 0.9. The inhibition of [3H]apomorphine binding with the Hill coefficient of 0.4 which was shown by haloperidol and spiroperidol was not observed for sulpiride and metoclopramide. Previously, we demonstrated non- and positive-cooperative [3H]apomorphine binding to stiatal membranes. In the present study, it has been also shown that sulpiride inhibits non-cooperative [3H]apomorphine binding leaving that with allosteric properties unaffected. No inhibition of dopamine-sensitive adenylate cyclase was observed by 10(-4) M sulpiride while 90% inhibition was obtained with 10(-5) M haloperidol. From those results, it is suggested that non-cooperative [3H]spomorphine binding is not coupled with dopamine-sensitive adenylate cyclase.

Adenylyl Cyclases↗
PubMed1980

Retinotoxic effects of diaminodiphenoxybutane in rats.

The effects of diaminodiphenoxybutane (DAPB) on visual function in rats were studied using behavioral, electrophysiological and histological techniques. A light-dark discrimination test was conducted by an operant behavioral method. DAPB did not modify intensity detection threshold at an intravenous dose of 35 mg/kg, but elevated it at doses of 50 and 70 mg/kg. Secondly, DAPB did not produce any changes in either electroretinogram (ERG) or visually evoked potential (VEP) at the dose of 35 mg/kg, but a marked decrease in the amplitude of the ERG a- and b-waves appeared after the doses of 50 and 70 mg/kg. The latency of the VEP first wave was also prolonged dose-dependently. Finally, retinal lesions were revealed in rats receiving 70 mg/kg. These results indicate that DAPB has a toxic effect on the retina in rats.

Animals↗
PubMed1980

New type of antibody-enzyme conjugate which specifically kills Candida albicans.

A new type of antibody-enzyme conjugate was made, and its possible application to Candida infection was studied. Both lactoperoxidase and xanthine oxidase were conjugated to specific antibody against Candida albicans. In vitro microbiocidal activity of the new antibody-enzyme conjugate, when incubated together with xanthine and minute amount of halides, showed a remarkable level of candidacidal ability. When the new antibody-enzyme conjugate was given to Candida-infected mice, followed by injecting xanthine and a minute amount of halides, about 50% of these heavily infected mice survived, whereas all control nontreated mice died. These data suggest that the further eleboration of this new antibody-enzyme conjugate might lead us to improve our therapeutic methods of clinical medicine.

Animals↗
PubMed1978

Aspects of the pharmacology and pharmacokinetics of nitroimidazoles with special reference to tinidazole.

Tinidazole has been reported to be highly effective against trichomoniasis, giardiasis and amoebiasis. In vitro, tinidazole is more active against trichomonads than metronidazole and possesses antiprotozoal activity at least comparable to metronidazole against Entamoeba histolytica, Tinidazole gives higher serum levels in animals following oral administration than metronidazole and is well distributed in organs and tissues. When tinidazole or metronidazole is given to healthy volunteers at a dose of 2g orally, the serum level of tinidazole at 48h is considerably higher than that of metronidazole. At 72h tinidazole is still present but metronidazole is not. These pharmacokinetic differences result from the longer half-life of tinidazole. These findings suggest that tinidazole might prove to be more useful than metronidazole in the treatment of protozoal infections when given in once daily oral doses of 2g.

Animals↗