RESUMEN
Previous studies indicated the presence of high concentrations of nickel in the "El truchón" ponds (in México), so it was necessary to find a possible correlation between sediment physicochemical properties of this water body and the damage that could be produced on the rainbow trout which culture is done in a rustic reservoir. The study was initiated with the determination of the physicochemical properties of the trout farm sediments, which are; granular composition, total nitrogen percentage, organic matter content, pH, redox potential, cationic interchange capacity, and Ni concentration. LC50 of Ni at 96 h was determined on Onchorynchus mykiss in the system water-sediment from the trout farm at equilibrium time. In the same system the sublethal toxicity of Ni was evaluated by the determination of metallotioneine (MT) levels, o-demethylase activity (OD) and protein concentration. The results showed a significant increment in the three-biochemical parameters. A linear relation was observed between Ni concentration and MT, OD and protein concentration, so these damage biomarkers are recommended in order to evaluate Ni toxicity. Probably these effects were due to the physicochemical characteristics of the sediments, which may give a high capacity to store metal in it. According to the obtained results it was suggested not to use rustic ponds in the fish culture, and use concrete ponds to avoid the accumulation of toxic compounds or make periodic sediments remotion.
Asunto(s)
Sedimentos Geológicos/química , Branquias/efectos de los fármacos , Níquel/toxicidad , Oncorhynchus mykiss/metabolismo , Contaminantes Químicos del Agua/toxicidad , Animales , Branquias/metabolismo , Dosificación Letal Mediana , Metalotioneína/análisis , Metalotioneína/efectos de los fármacos , México , Oxidorreductasas O-Demetilantes/análisis , Oxidorreductasas O-Demetilantes/efectos de los fármacosRESUMEN
DNA methylation plays an important role in controlling gene-expression programs. Increasing evidence indicates that the enzyme responsible for replicating the DNA methylation pattern, DNA methyltransferase 1 (DNMT1), has a role in cancer. In this article, it is suggested that DNMT1 is a multifunctional protein that has regulatory activities in addition to DNA methylation activity. These functions are assembled into one protein to ensure the coordinate replication of DNA and its methylation pattern. The regulatory activities of DNMT1 are proposed to be involved in cellular transformation and should, therefore, serve as the targets for novel anti-cancer agents.
Asunto(s)
ADN (Citosina-5-)-Metiltransferasas/metabolismo , Metilación de ADN , Expresión Génica/fisiología , Animales , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Ciclo Celular/efectos de los fármacos , Ciclo Celular/fisiología , ADN (Citosina-5-)-Metiltransferasa 1 , ADN (Citosina-5-)-Metiltransferasas/antagonistas & inhibidores , Metilación de ADN/efectos de los fármacos , Expresión Génica/efectos de los fármacos , Humanos , Oligonucleótidos Antisentido/farmacología , Oligonucleótidos Antisentido/uso terapéutico , Oxidorreductasas O-Demetilantes/efectos de los fármacos , Oxidorreductasas O-Demetilantes/metabolismo , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/metabolismoRESUMEN
Five days intraperitoneal administration of rats with chlordiazepoxide (0.4 mg/kg), griseofulvin (7 mg/kg), rifampicin (8. 6 mg/kg), phenytoin (4.3 mg/kg) and phenobarbitone (1.4 mg/kg; an established inducer of microsomal enzymes) caused a significant increase in serum triacylglycerol (P<0.001) and the activities of aniline hydroxylase, aminopyrine N-demethylase and p-nitroanisole O-demethylase (P<0.001). Aniline hydroxylase, aminopyrine N-demethylase and p-nitroanisole O-demethylase activities were increased 1.48-, 1.15- and 1.47-fold, respectively, in chlordiazepoxide-treated rats, 1.65-, 1.20- and 1.38-fold in griseofulvin-treated rats, 1.74-, 1.36- and 1.44-fold in rifampicin-treated rats, 1.56-, 1.29- and 1.62-fold in phenytoin-treated rats and 2.26-, 1.72- and 1.93-fold in phenobarbitone-treated rats. Chlordiazepoxide, griseofulvin, rifampicin, phenytoin and phenobarbitone increased the activity of cytosolic phosphatidate phosphohydrolase by 52, 58, 67, 73 and 82%, respectively, while the drugs elicited 50, 60, 60, 73 and 87% increases in the activity of the microsomal phosphatidate phosphohydrolase. Similarly, chlordiazepoxide, griseofulvin, rifampicin, phenytoin and phenobarbitone elicited 2.4-, 2.39-, 2.34-, 1.69- and 3.75-fold increases in serum triacylglycerol concentrations. The correlations between serum triacylglycerol concentrations and the activities of aniline hydroxylase, aminopyrine N-demethylase and p-nitroanisole O-demethylase were significant in all treatment groups (r=0.83, r=0.92 and r=0.87, respectively, n=30, P<0.001). Our results suggest that induction of hepatic enzymes by the administered drugs may lead to hypertriglyceridaemia as an adverse effect, possibly by inducing the activity of regulatory enzymes in the biosynthesis of triglyceride.
Asunto(s)
Clordiazepóxido/farmacología , Griseofulvina/farmacología , Hígado/efectos de los fármacos , Fenitoína/farmacología , Rifampin/farmacología , Triglicéridos/sangre , Aminopirina N-Demetilasa/efectos de los fármacos , Aminopirina N-Demetilasa/metabolismo , Anilina Hidroxilasa/efectos de los fármacos , Anilina Hidroxilasa/metabolismo , Animales , Peso Corporal/efectos de los fármacos , Citosol/efectos de los fármacos , Citosol/metabolismo , Activación Enzimática/efectos de los fármacos , Inducción Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Inactivación Metabólica , Hígado/anatomía & histología , Hígado/enzimología , Masculino , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Tamaño de los Órganos/efectos de los fármacos , Oxidorreductasas O-Demetilantes/efectos de los fármacos , Oxidorreductasas O-Demetilantes/metabolismo , Fosfatidato Fosfatasa/efectos de los fármacos , Fosfatidato Fosfatasa/metabolismo , Ratas , Ratas WistarRESUMEN
The effects of 50 Hz, 1.2 mT magnetic fields (MFs) were tested on hepatic monooxygenase enzymes of basal and beta-naphthoflavone-phenobarbital-preinduced rats and mice. An inductive effect on cytochrome P-450 level and on some enzymatic cytochrome P-450-dependent activities was observed in basal mice after MF exposure. Enzymatic activities in preinduced mice and rats were reduced by MFs, the degree of reduction depending on the enzyme. A specific inhibitory effect was determined in some of the assayed activities and in the relative peculiar P-450 isoforms detected by Western blot analysis.
Asunto(s)
Campos Electromagnéticos , Hígado/enzimología , Magnetismo , Oxidorreductasas/efectos de la radiación , 7-Alcoxicumarina O-Dealquilasa/efectos de los fármacos , 7-Alcoxicumarina O-Dealquilasa/efectos de la radiación , Anilina Hidroxilasa/efectos de los fármacos , Anilina Hidroxilasa/efectos de la radiación , Animales , Benzoflavonas/farmacología , Western Blotting , Citocromo P-450 CYP2B1 , Citocromo P-450 CYP2E1 , Sistema Enzimático del Citocromo P-450/efectos de los fármacos , Sistema Enzimático del Citocromo P-450/efectos de la radiación , Isoenzimas/efectos de los fármacos , Isoenzimas/efectos de la radiación , Hígado/efectos de los fármacos , Hígado/efectos de la radiación , Ratones , Microsomas/efectos de los fármacos , Microsomas/enzimología , Microsomas/efectos de la radiación , Oxidorreductasas/efectos de los fármacos , Oxidorreductasas N-Desmetilantes/efectos de los fármacos , Oxidorreductasas N-Desmetilantes/efectos de la radiación , Oxidorreductasas O-Demetilantes/efectos de los fármacos , Oxidorreductasas O-Demetilantes/efectos de la radiación , Fenobarbital/farmacología , Ratas , Ratas Wistar , beta-naftoflavonaRESUMEN
Administration of allylestrenol or benzpyrene in fetal and neonatal periods of life make the rats susceptible to phenobarbiturate induction. Changes to controls could be observed in three of the enzyme activities tested (p-nitrophenol-hydroxylase, cytochrome P450 and aniline-hydroxylase), with a dominance of the p-nitrophenol-hydroxylase among them. There seemed to be no difference in the action of allylestrenol and benzpyrene, although treatment protocol in the neonatal period proved to be more effective.