150 resultados para subacute toxicity


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Pollution and industrial practices result in concentrations of metals and other environmental agents that are related to environmental toxicity. A rat bioassay was utilized for the identification of toxic effects of cadmium intake. This demonstrated increased total urinary proteins and increased kidney weights in rats exposed to CdCl2, for 7 days, in drinking water (100 mg/L). Serum creatinine, total and direct bilirubin concentrations and alanine transaminase activity were increased in Cd-exposed rats, indicating renal and hepatic toxicity. It was also observed that lipoperoxide concentrations were increased, while Cu-Zn superoxide dismutase activity was decreased in rats treated with cadmium. This indicated that the renal and hepatic toxicity induced by cadmium involved superoxide radicals. (C) 1998 Academic Press.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Two species of plants commonly known as barbatim (a) over tildeo occur in Brazil, Stryphnodendron adstringens (Fabaceae) (true barbatim (a) over tildeo) and Dimorphandra mollis (Caesalpiniaceae) (false barbatim (a) over tildeo). These two species have a similar flowering period and are considered by beekeepers to cause bee mortality during this period. Flowers were collected from both species, dehydrated, ground and incorporated into an experimental diet for bees of two different species, Apis mellifera and Scaptotrigona postica. Both plant species were toxic to A. mellifera, reducing their median survival. D. mollis was toxic to S. postica, and Stryphnodendron adstringens reduced median survival of this bee species even when used at a concentration of 2.5%. In a choice experiment carried out with A. mellifera and the two plant species, the honey bees could choose not to feed on the diets containing the flowers, and feed on sugar and honey instead, but they did not. This shows us that the flowers of S. adstringens were not repellent to the bees. The plants were more toxic to A. mellifera than to Scaptotrigona postica, a result that can be explained by the fact that A. mellifera was introduced into Brazil whereas S. postica is a native stingless bee.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The effects of exposure to lead on endocrine function and the reproductive parameters were studied in pubertal rats treated with 1.0 g l(-1) lead acetate in drinking water for 20 days (subacute group) or 9 months (chronic group) in addition to i.v. injections of lead acetate (0.1 mg 100 g(-1) body wt.) every 10 (subacute group) or 15 days (chronic group). Although basal levels of testosterone were higher both in plasma and in testes of acutely intoxicated animals, the circulating levels of luteinizing hormone (LH) were not affected in either group, nor was the LH-releasing hormone content of the median eminence. The density of [I-125]LH/human chorionic gonadotrophin (hCG) binding sites in testicular homogenates was reduced by saturnism in both groups, concomitant with a significantly increased apparent affinity constant of the hormone-receptor complex. These data can be viewed as the result of a mixture of specific lead toxicity (e.g. at the enzyme level) with other more general actions (e.g. at the level of the hypothalamus-pituitary-testicular axis).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Lignans from Virola sebifera Aubl., Virola sp., and Otoba parvifolia (Mkfg.) A. Gentry (Myristicaceae) inhibited the in vitro growth of the fungus cultivated by leaf-cutting ants of the species Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae). A comparison of activity among the lignans was obtained.