Decreased arginine methylation and myelin alterations in arsenic exposed rats.

Methylation has an important role in the synthesis of myelin basic protein (MBP), an essential component that confers compactness to myelin, and the correct synthesis and assembling of myelin are fundamental in the development of the central nervous system. Since arsenic metabolism requires a high consumption of S-adenosylmethionine, the main donor of methyl groups in the organism, it has been proposed that arsenic exposure can lead to a demethylation status in the organism comprising DNA and protein hypomethylation. This study documents myelin alterations in brain and changes in levels of methylated arginines in brain and serum of adult female Wistar rats exposed to arsenic (3 and 36 ppm, drinking water) from gestation throughout lactation, development and until 1, 2, 3 and 4 months of age.

Time course of arsenic species in the brain and liver of mice after oral administration of arsenate.

The understanding of the biomethylation process of arsenic is essential to uncover the mechanisms of arsenic toxicity. This work analyzes the time course of arsenic species in the brain and liver of adult mice, after a single oral administration of three arsenate doses [2.5, 5.

Decreased nitric oxide production in the rat brain after chronic arsenic exposure.

Chronic arsenic exposure is associated with nervous system damage, vascular disease, hepatic and renal damage as well as different types of cancer. Alterations of nitric oxide (NO) in the periphery have been detected after arsenic exposure, and we explored here NO production in the brain. Female Wistar rats were exposed to arsenite in drinking water (4-5 mg/kg/day) from gestation, lactation and until 4 months of age.

Fluoride-induced disruption of reproductive hormones in men.

Fluoride-induced reproductive effects have been reported in experimental models and in humans. However, these effects were found in heavily exposed scenarios. Therefore, in this work our objective was to study reproductive parameters in a population exposed to fluoride at doses of 3-27 mg/day (high-fluoride-exposed group-HFEG).

Levels of dichlorodiphenyltrichloroethane and deltamethrin in humans and environmental samples in malarious areas of Mexico.

Mexico used dichlorodiphenyltrichloroethane (DDT) to control malaria until 1999, when it was replaced with deltamethrin for mosquito control. Thus, we performed environmental and exposure assessments to DDT and deltamethrin in the states of Chiapas and Oaxaca. In Chiapas, samples were obtained at the time when DDT was being used in the malaria control program, while in Oaxaca, samples were collected 2 years after the final spraying of DDT and 2 days after deltamethrin application.