Toxicity induced by dieldrin and chlorpyrifos in the freshwater crayfish Cambarellus montezumae (Cambaridae).

The toxicity induced by insecticides in aquatic organisms is of utmost relevance because it may give a clue about the degree of health or damage of the involved ecosystem. In the present report, we determined the effect of dieldrin (DD) and chlorpyrifos (CP) on the freshwater crayfish, Cambarellus montezumae. The organisms (4-6 cm in diameter) were collected in the Ignacio Ramirez Reservoir, situated at 50 km Northeast of Mexico City, in the Rio Lerma Basin.

Inhibition of mitomycin C-induced sister chromatid exchanges by vitamin C in vivo.

The aim of this experiment was to test the modulation of genotoxicity produced by vitamin C (V-C) challenged against mitomycin C (MMC) in vivo, by analyzing the sister chromatid exchanges (SCE) and cell proliferation kinetics. We used the mouse bone marrow cytogenetic method, and tested three dosages of V-C (3, 5, and 7 g/kg of body weight), along with the appropriate positive (2 mg MMC/kg body weight) and negative V-C controls. The results showed that V-C caused a strong inhibition of SCEs induced by MMC in the three dosages administered.