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Biomedical subjects

R Nishigaki

Publications and source records attributed to R Nishigaki.

59 records · Page 4Linked to original sources

Effect of chlorpromazine on intestinal absorption of sulfamethoxazole in rats.

The effect of chlorpromazine (CPZ) on the intestinal absorption of sulfamethoxazole (SMZ) was studied in isolated perfused rat small intestine by comparing two determinants, i.e. the epithelial permeability and the intestinal blood flow. The appearance rate of SMZ in blood in the presence of CPZ decreased to one-half of the control without CPZ. The pH of perfusion solution was significantly decreased by CPZ after 10 min perfusion. According to the Winne's absorption model, CPZ did not change the apparent epithelial permeability of SMZ, but decreased the epithelial permeability of unionized SMZ due to the decrease in the pH of perfusion solution by CPZ. It was also suggested that CPZ decreased the fraction of the total blood flow rate in the subepithelial capillaries to less than one-half.

Animals↗

Sonodynamically induced cell damage with 4'-O-tetrahydropyranyladriamycin, THP.

BACKGROUND: 4'-O-tetrahydropyranyladriamycin (THP) is a novel anthracycline derivative with cardiotoxicity significantly lower than ADM. In this study, the ultrasonically induced in vitro cell damaging effect of THP was investigated. MATERIALS AND METHODS: Sarcoma 180 cells suspended in air-saturated PBS were exposed to ultrasound for up to 60 s in the presence and absence of THP. The viability of the isolated cells was determined by staining of the cells with Trypan Blue dye. RESULTS: The rate of inducing cell damage with ultrasound was doubled with 80 microM THP, while no cell damage was observed with THP alone. CONCLUSION: The enhancement of ultrasonically induced in vitro cell damage was demonstrated with THP. This enhancement was significantly inhibited by histidine, which may suggest a sonochemical mechanism.

Animals↗

Ultrasonically induced cell damage enhanced by photofrin II: mechanism of sonodynamic activation.

UNLABELLED: Ultrasonically induced cell damage and active oxygen generation with photofrin II (PF) were compared in the same in vitro insonation setup. MATERIALS AND METHODS: Sarcoma 180 cells suspended in air-saturated PBS were exposed to ultrasound for up to 60 seconds in the presence and absence of PF. The viability was determined by the Trypan Blue exclusion test. Ultrasonically induced active oxygen generation in the presence and absence of PF in air-saturated aqueous solutions of 50 mM 2,2,6,6-tetramethyl-4-piperidone was detected by electron spin resonance (ESR) spectrum. RESULTS: Significant enhancement of the rates of both ultrasonically induced cell damage and nitroxide generation was demonstrated with 20-80 micrograms/ml PF. Both rates correlated very well. The enhancement of both rates with PF was suppressed by 10 mM histidine. CONCLUSION: These results may suggest that ultrasonically generated active oxygen plays a primary role in ultrasonically induced cell damage in the presence of PF.

Animals↗