RESUMO
Microspectrofluorometry allows to obtain the fluorescence spectrum of an isolated living cell. When cells are preincubated with 1,4 diacetoxy-2,3 dicyanobenzol the cellular fluorescence spectrum can be resolved in its components i.e. the characteristic fluorescence spectrum of each ionized forms of the probe and the intrinsic cell fluorescence spectrum due to NAD(P)H. This allows the determination of the intracellular pH with good accuracy. Furthermore, comparison between the intensity of the intrinsic cell fluorescence and the probe fluorescence intensity offers us an opportunity to monitor the intracellular amount of the drug.
Assuntos
Líquidos Corporais , Hidroquinonas , Líquido Intracelular , Nitrilas , Animais , Ciclo Celular , Células Cultivadas , Espaço Extracelular , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Microquímica , Espectrometria de FluorescênciaRESUMO
The acute toxicities of dimethylnitrosamine and diethylnitrosamine have been evaluated in adult male crayfish Austropotamobius pallipes; LD50 values are 2250 mg/kg and 230 mg/kg, respectively. Toxicokinetic studies of 14C-dimethylnitrosamine and 14C-diethylnitrosamine in crayfish, administered by i.v. injection, show high concentrations of 14C in abdominal muscle and hepatopancreas. Excretion is greater with dimethylnitrosamine, and retention in the tissues, especially the hepatopancreas, is greater with diethylnitrosamine. Metabolites identified in excreta include monomethylnitrosamine from dimethylnitrosamine, and hydroxyethyl-ethyl-, bishydroxyethyl- and carboxyethyl-ethylnitrosamine from diethylnitrosamine.
