Seasonal variation in cortisol biomarkers in Hispanic mothers living in an agricultural region.

Context: Characterization of stress exposure requires understanding seasonal variability in stress biomarkers.

Objective: To compare acute and chronic stress biomarkers between two seasons in a cohort of rural, Hispanic mothers.

Methods: Stress questionnaires and cortisol measurements (hair, blood and saliva) were collected in the summer and fall.

Involvement of N-6 adenine-specific DNA methyltransferase 1 (N6AMT1) in arsenic biomethylation and its role in arsenic-induced toxicity.

Background: In humans, inorganic arsenic (iAs) is metabolized to methylated arsenical species in a multistep process mainly mediated by arsenic (+3 oxidation state) methyltransferase (AS3MT). Among these metabolites is monomethylarsonous acid (MMAIII), the most toxic arsenic species. A recent study in As3mt-knockout mice suggests that unidentified methyltransferases could be involved in alternative iAs methylation pathways.