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Biomedical subjects

M Tsuruoka

Publications and source records attributed to M Tsuruoka.

63 records · Page 4Linked to original sources
PubMed1981

Enhanced bioavailability of digoxin by gamma-cyclodextrin complexation.

Inclusion complex of digoxin with gamma-cyclodextrin (gamma-CyD) in 1:4 molar ratio was prepared, and its dissolution and absorption behaviors were compared with those of digoxin alone. The dissolution rate of digoxin in water was found to be markedly increased by gamma-CyD complexation. Bioavailability of digoxin following the oral administration of gamma-CyD complex to dogs was 5.4 times as much as that of digoxin alone. The present data did indicate improvement of dissolution and absorption characteristics of digoxin by inclusion complexation, suggesting the decrease in dose in oral digoxin therapy.

Animals↗
PubMed1980

Alteration in enzyme activities of de novo phosphatidylcholine biosynthesis in rat liver by treatment with typical inducers of microsomal drug-metabolizing system.

1. The activities of choline kinase, ethanolamine kinase, cholinephosphate cytidylytransferase(s) and cholinephosphotransferase were compared in the liver subcellular fractions after the treatment of rats for two successive days with phenobarbital, 3-methylcholanthrene and polychlorinated biphenyls. 2. The administration of phenobarbital resulted in a significant decrease in choline kinase activity while not affecting ethanolamine kinase activity. Both 3-methylcholanthrene and polychlorinated biphenyls caused considerable enhancement of choline kinase activity concomitantly with ethanolamine kinase activity. 3. The activity of cytosolic cytidylytransferase was not affected by any of the inducers while the microsomal activity was significantly depressed by the administration of either phenobarbital or polychlorinated biphenyls. 4. The activity of microsomal cholinephosphotransferase decreased significantly after the treatment with both 3-methylcholanthrene and polychlorinated biphenyls and increased slightly after phenobarbital administration. 5. The observed opposite effects of phenobarbital and 3-methylcholanthrene on the enzymes in de novo phosphatidylcholine synthesis indicate that there exist a possible relation between induction of microsomal drug-metabolizing system and modulation of phosphatidylcholine biosynthesis in animal liver.

Animals↗
PubMedDate not supplied

Comparative effects of diethyldithiocarbamate and N-benzyl-D-glucamine dithiocarbamate on cis-diamminedichloroplatinum-induced toxicity in kidney and gastrointestinal tract in rats.

Sodium diethyldithiocarbamate (DDTC) and sodium N-benzyl-D-glucamine dithiocarbamate (BGD) were compared for their protective effects against cis-diamminedichloroplatinum (DDP)-induced toxicity in kidney and gastrointestinal tract in rats. Rats were injected i.p. with the dithiocarbamates (2.0 mmol kg-1) immediately or 1 h after i.v. injection of DDP (20 mumol kg1). Treatment with BGD immediately or at 1 h after DDP injection effectively prevented the nephrotoxicity of DDP, but administration of DDTC immediately or 1 h after DDP afforded little protection. N-Benzyl-D-glucamine dithiocarbamte significantly reversed the reduction in maltase, sucrase and aminopeptidase activities of jejunal mucosa of rats treated with DDP, whereas treatment with DDTC concurrent with DDP could not reverse the reduction in disaccharidase activity following DDP injection. The platinum concentrations in liver and kidney were significantly decreased by treatment with BGD and DDTC. The treatment with DDTC at 1 h after DDP was more effective on the reduction of platinum concentrations in these tissues than that immediately after DDP. There was no difference between the renal and hepatic concentrations of platinum in two time intervals of BGD. The pharmacokinetic studies indicated that DDTC is more rapidly metabolized than BGD, resulting in larger total clearance and elimination rate constant values. These results reveal that the administration of BGD immediately and at 1 h after DDP can protect against the renal and gastrointestinal toxicities caused by DDP, whereas DDTC afforded little protection, and that the time interval between administration of DDP and DDTC greatly influences its protective effect on DDP-induced toxicity, indicating that the chelation therapy of BGD for DDP is superior to that of DDTC.

Animals↗