The broad scope of health effects from chronic arsenic exposure: update on a worldwide public health problem.

Background: Concerns for arsenic exposure are not limited to toxic waste sites and massive poisoning events. Chronic exposure continues to be a major public health problem worldwide, affecting hundreds of millions of persons.

Objectives: We reviewed recent information on worldwide concerns for arsenic exposures and public health to heighten awareness of the current scope of arsenic exposure and health outcomes and the importance of reducing exposure, particularly during pregnancy and early life.

Protein expression in the livers and urinary bladders of hamsters exposed to sodium arsenite.

Hamsters were exposed to sodium arsenite (173 mg As/L) in drinking water for 6 days and control hamsters were given tap water. Equal amounts of protein from the urinary bladder or liver extracts of control and arsenic-treated hamsters were labeled with Cy3 and Cy5 dyes, respectively. The labeled proteins were mixed and separated in the two-dimensional differential in gel electrophoresis (2D-DIGE).

Glutathione-S-transferase-omega [MMA(V) reductase] knockout mice: enzyme and arsenic species concentrations in tissues after arsenate administration.

Inorganic arsenic is a human carcinogen to which millions of people are exposed via their naturally contaminated drinking water. Its molecular mechanisms of carcinogenicity have remained an enigma, perhaps because arsenate is biochemically transformed to at least five other arsenic-containing metabolites. In the biotransformation of inorganic arsenic, GSTO1 catalyzes the reduction of arsenate, MMA(V), and DMA(V) to the more toxic +3 arsenic species.

Interactions of sodium selenite, glutathione, arsenic species, and omega class human glutathione transferase.

Human monomethylarsenate reductase [MMA(V) reductase] and human glutathione S-transferase omega 1-1 (hGSTO1-1) [because MMA(V) reductase and hGSTO1-1 are identical proteins, the authors will utilize the designation "hGSTO1-1"] are identical proteins that catalyze the reduction of arsenate, monomethylarsenate [MMA(V)], and dimethylarsenate [DMA(V)]. Sodium selenite (selenite) inhibited the reduction of each of these substrates by the enzyme in a concentration-dependent manner. The kinetics indicated a noncompetitive inhibition of the MMA(V), DMA(V), or arsenate reducing activity of hGSTO1-1.