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The aim of the study was to evaluate the effect of acetaminophen (APAP) and/or trichloroethylene (TRI) on the liver cytochrome P450-dependent monooxygenase system, CYP2E1 and CYP1A2 (two important P450 isoforms), and liver glutathione (GSH) content in rats. Rats were given three different doses of APAP (250, 500 and 1000 mg/kg b...) and then the above-mentioned parameters were measured for 48 h. The lowest APAP dose produced small changes in the cytochrome P450 content of liver. At 500 mg/kg APAP increased the cytochrome P450 content to 230% of the control. The inductive effect was seen at 1000 mg/kg dose but at 24 h and later. NADPH-cytochrome P450 reductase activity was the highest after the lowest dose of APAP, while after the highest dose it was equal to the control value. TRI increased both the cytochrome P450 content and the NADPH-cytochrome P450 reductase activity. When TRI was combined with APAP, both these parameters increased in the first hours of observation, but they returned to the control values at 24 h. When APAP was given at 250 mg/kg, GSH levels decreased to 55% of the control at 8 h and returned to the control values at 24 h. The higher doses of APAP decreased GSH levels more than the lowest dose, but after 24 h GSH levels did not differ from those of the control. When TRI was given at 250 mg/kg, the GSH levels decreased to 68% of the control at 2 h and then they increased gradually and tended to exceed the control values at 48 h. The effect of TRI combined with APAP on the level of GSH was virtually the same as that of APAP alone given at 500 mg/kg.
The influence of acetylsalicylic acid (ASA) on elimination of trichloroacetic acid and trichloroethanol in the urine and liver and kidney of cytochrome P-450-dependent monooxygenase systems in rats exposed to trichloroethylene (TRI) vapours were examined. The obtained results show that acetylsalicylic acid decreased the elimination of both trichloroethylene metabolites and induced cytochrome P-450 concentration in the liver, whereas slightly inhibited cytochrome b5 and activites of NADPH-cytochrome P-450 reductase and NADH-cytochrome b5 reductase. After mixed exposures, acetylsalicylic acid elevated cytochrome P-450 concentration and NADPH-cytochrome P-450 reductase activity to values observed in the control group. The concentration of cytochrome b5 was much lower than after ASA or trichloroethylene alone. The activity of NADPH-cytochrome P-450 reductase was strongly inhibited by TRI, whereas in ASA presence was elevated, but it was still lower than in control. Acetylsalicylic acid stimulates cytochrome P-450, however other compounds of MFO system do not react positively on this ester.
This study aimed at evaluating the effect of acetylsalicylic acid (ASA) (150 and 300 mg/kg b.w.) on urinary trichloroethanol and trichloroacetic acid excretion and the liver cytochrome P-450-dependent monooxygenase system (MFO) in rats treated with trichloroethylene (TRI) alone or with xylene (XYL) at a concentration of 4.5 mmol/m3 air. The study has shown that xylene equally decreased trichloroacetic acid and trichloroethanol excretion within 48 hours after exposure. Acetylsalicylic acid diminished the excretion of both trichloroethylene metabolites in a dose-dependent manner, although the effect was weaker than that of xylene.Liver cytochrome P-450 content tended to increase after both doses of ASA. There were no significant changes in cytochrome b5 content and the activities of NADPH-cytochrome P-450 and NADH-cytochrome b5 reductases. TRI decreased cytochrome P-450 and cytochrome b5 contents and reduced both reductase activities. XYL induced all MFO components. Acetylsalicylic acid at 150 mg/kg combined with TRI inhalation tended to lower cytochrome b5 content and NADH-cytochrome b5 reductase activity. When given at 300 mg/kg, ASA increased cytochrome P-450 content, while cytochrome b5 content and NADH-cytochrome b5 reductase activity were still decreased, but to a smaller degree when compared with the lower ASA dose. XYL together with the lower dose of ASA induced the MFO system. Exposure to XYL and the higher dose of ASA elevated cytochrome P-450 content and NADPH-cytochrome P-450 reductase activity and it diminished NADH-cytochrome b5 reductase activity. In rats treated simultaneously with ASA, XYL and TRI both cytochromes increased in amount, while the other components of the MFO system did not change.
Przebadano wpływ trichloroetylenu na wydalanie fenolu u szczurów poddanych łącznym ekspozycjom inhalacyjnym na równo- i różnomolowe mieszaniny benzenu i trichloroetylenu.
Przebadano wydalanie kwasu trichlorooctowego i trichloroetanolu u szczurów poddanych pięciodniowym ekspozycjom na sam trichloroetylen (TRI) lub łącznie z toluenem po jednoczesnym podaniu etanolu. Wykazano, że oba związki zmieniają wydalanie głównych metabolitów trichloroetylenu.
Przebadano wydalanie kwasu trichlorooctowego i trichloroetanolu u szczurów poddanych pięciodniowym ekspozycjom inhalacyjnym na trichloroetylen pojedynczo lub łącznie z ksylenem po jednoczesnym podaniu etanolu. Wykazano, że obydwa ksenobiotyki po podaniu oddzielnym hamują wydalanie obu metabolitów trichloroetylenu. Alkohol etylowy i ksylen podane łącznie, silniej niż po narażeniu pojedynczym, hamują wydalanie kwasu trichlorooctowego, natomiast słabiej obniżają wydalanie trichloroetanolu.
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