1,721,165 research outputs found
Residui nelle uova
No full textCaratteristiche della cinetica di eliminazione dei farmaci impiegati nelle galline ovaiole. Distribuzione dei residui tra tuorlo e albume
Triphenyltin acetate (TPTA)-induced cytotoxicity to mouse thymocytes.
No full textTo perform a better investigation of the toxic activity of triphenyltin acetate (TPTA) already described in vivo, primary cultures of murine thymocytes were incubated for 2 to 32 h with graded amounts (0.5-8 microM) of the triorganotin compound. The cytotoxic activity has been evaluated with the Trypan blue dye exclusion test, the 3-(4,5-dimethyl-thiazol-2-yl)-2,5 diphenyl-tetrazolium bromide (MTT) assay for cell survival and the cellular release of lactate dehydrogenase. Following 2 h of incubation with TPTA, a dose-dependent reduction (P < 0.05) of cellular viability occurred and marked increases (P < 0.05) of the MTT cytotoxic index and of lactate dehydrogenase leakage were also observed. These findings indicate that TPTA is as cytotoxic to mice thymocytes, as other triphenyltin derivatives are to other species
Postnatal development of hepatic, hydrolytic and conjugative drug-metabolizing enzymes in female horses
No full textLittle is known about the effects of aging on the hepatic drug metabolizing capacity of horses despite the relatively long lifespan characterizing this species. A wide array of cytochrome P450 (CYP)-dependent monooxygenases, carboxylesterases and transferases were assayed in liver microsomes from 50 female horses in an age range between less than 1 year to over 12 years. Rather unexpectedly, both the CYP content and the activity of NADPH cytochrome c reductase rose as a function of age. Accordingly, a general increasing trend was recorded in the rate of the in vitro metabolism of the substrates reported to be related to CYP2B-, CYP2E- or CYP3A, although, as detected by Western immunoblotting, only the levels of proteins recognized by anti-rat CYP3A- and CYP2B antibodies appeared to increase consistently. Also the carboxylesterases and uridindiphosphoglucuronyl-transferase (UGT) activity toward 1-naphthol displayed a similar trend, glutathione S-transferase accepting 3,4-dichloronitrobenzene as a substrate being the only enzyme activity showing an age-related decline. A positive correlation was also found between liver cadmium content and CYP amount as well as the activities of most monooxygenases (except for those related to CYP1A), carboxylesterases, and UGT. While confirming that a number of enzyme activities are less expressed in foals, our results contradict the general view that the drug metabolizing capacity drops in elder individuals. Although several other factors can influence the kinetics of foreign compounds in aged animals, data from this study may provide insight in understanding possible age-related differences in drug efficacy and the response to toxic substances in horse
Subacute toxicity of triphenyltin acetate (TPTA) in the rabbit: clinical observations and hematologic, hematochemical and enzymatic changes
No full textTwenty-eight immature male rabbits were divided into four experimental groups and administered a standard diet containing respectively 0, 15, 75 and 150 ppm of triphenyltin acetate (TPTA) for 70 days. The highest dose group showed a decrease in erythrocyte count, haemoglobin content and packed cell volume. As early as on day 35, leucopenia and lymphopenia were recorded in all treated groups, thereby confirming the well-known immunosuppressive activity of organo-tin compounds. Both total serum protein and albumin levels apparently altered by TPTA treatment. Conversely, there was a dose-dependent increase for both alpha 2-globulin fraction and blood urea nitrogen serum levels, suggesting a possible renal involvement
CD4+, CD8+ lymphocyte depletion and cytotoxicity induced by the organotin TPTA in the mouse.
No full textGrowth promoter modulation of drug metabolizing enzymes gene expression in primary cultures of cattle hepatocytes
No full textEffects of triphenyltin acetate on lymphopoiethic system and hepatic and renal cytochrome P450 content in rabbits.
No full textEffects of the repeated oral administration of cimaterol and clenbuterol upon the liver drug metabolizing enzymes activities (DMEs) in the male chick
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