RESUMO
In the present study we have analyzed the production of reactive oxygen species by toxin T-514 of the genus Karwinskia in vitro (primary liver cell cultures and microsomes), as well as their possible role in its cytotoxicity. The role of catalase and superoxide dismutase (SOD) as defense mechanisms against oxidative stress was also studied. Freshly isolated hepatocytes or microsomes were exposed to T-514 in the presence or absence of catalase and SOD. Cytotoxicity was determined by methylthiazoltetrazolium (MTT) reduction. Oxidative stress was evaluated by the dichlorofluorescein diacetate (DCFDA) fluorescent probe and the reduction of ferricytochrome c. Exposure of hepatocytes to toxin T-514 for 2-, 4-, 6- and 24-h periods resulted in a time- and concentration-dependent increase in the suppression of mitochondrial metabolic activity. T-514 induced the production of reactive oxygen species in both hepatocytes and microsomes. Catalase and superoxide dismutase had a protective effect against the cytotoxicity of T-514 in hepatocytes and also inhibited the production of oxygen reactive species in microsomes. The results indicate that oxidative stress mediated by reactive intermediates may be a mechanism by which T-514 induces its cytotoxic effect.
Assuntos
Antracenos/efeitos adversos , Karwinskia/química , Estresse Oxidativo , Espécies Reativas de Oxigênio , Animais , Catalase/farmacologia , Citotoxinas , Hepatócitos , Fígado/citologia , Masculino , Microssomos Hepáticos , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Superóxido Dismutase/farmacologiaRESUMO
Industrial development has resulted in an increased release of chemicals and other agents into the environment, resulting in damage to the environment as well as increasing the risk of adverse effects on human health. Environmental toxicology (ET) is the discipline responsible for assessing the risks to human health and the environment from the effects of new chemicals and those already present in the environment. The development of human resources in toxicology is therefore a priority in both Latin America (LA) and the European Union (EU), although LA professionals are more involved in risk evaluation than in risk assessment compared to their EU colleagues. A solid background in general toxicology will enable those interested in environmental issues to tackle local problems. Moreover, the increasing globalization of markets and, therefore, of the necessary regulations, requires harmonisation of postgraduate programmes to ensure that risk assessment and management related to the environment are dealt with uniformly and by highly qualified scientists. The Inaugural Meeting of the ALFA-OMET Toxicology', a 2-year programme supported by the European Commission, offered the opportunity to discuss a number of these issues. The present status of existing ET courses in the EU and LA and the corresponding professional profiles in the two regions were examined, and a harmonized academic curriculum for a postgraduate professional profiles in the two regions were examined, and a harmonized academic curriculum for a postgraduate course in environmental toxicology was developed. Finally, a course programme for toxicology and a specialization in environmental toxicology designed by a panel of experts was discussed, and its relevance as a model for other specialisation programmes was analysed. Exercises such as those performed by ALFA-OMET may be useful not only in promoting discussion for the implementation of national and international professional registers in LA, but also in encouraging the same, ongoing process in the EU.
Assuntos
Poluentes Ambientais/toxicidade , Toxicologia/educação , Europa (Continente) , América LatinaRESUMO
Se efectuó un estudio retrospectivo de las intoxicaciones registradas en el Hospital Universitario "Dr. José E. González" (H.U.) de 1980 a 1984 en el cual se consideraron los siguientes puntos: edad y sexo del paciente, tipo y modo de intoxicación, mortalidad y total de intoxicaciones en este periodo. El ingreso total de pacientes al H.U. fue de 182,247 del cual el 0.26% (477) correspondió a intoxicaciones siendo las más frecuentes: petróleo (Kerosene), cáusticos, salicilatos, alcohol etílico y atropina. El modo de intoxicación fue accidental en un 90% de los casos e intento de suicidio en 10%. La mayoría fueron niños (70%) y un 30% adultos; 277 masculinos y 200 femeninos. La mortalidad por intoxicaciones fue de 1.25% (6 de 477 pacientes) y las substancias relacionadas con estas muertes fueron digitálicos (3), salicilatos (1), talio (1) y cáusticos (1)