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ASSESSING HUMAN EXPOSURE AND GENOTOXIC EFFECTS IN HUMAN EXFOLIATED EPITHELIA FROM INDIVDUALS IVING IN AN ENDEMIC REGION IN INNER MONGOLAI
Citation:
Mumford, J. L., M Schmitt, J Allen, B. Collins, H. Ma, K. Wu, Y. Xia, Z. Ni, C. Lee, Z. Feng, AND D. Tian. ASSESSING HUMAN EXPOSURE AND GENOTOXIC EFFECTS IN HUMAN EXFOLIATED EPITHELIA FROM INDIVDUALS IVING IN AN ENDEMIC REGION IN INNER MONGOLAI. Presented at Society for Environmental Geochemistry and Health (SEGH), 4th International Conference on Arsenic Exposure and Health Effects, San Diego, CA, June 18-21, 2000.
Description:
A pilot study was conducted to characterize arsenic exposure and genotoxic effects in Ba Men located in West Central Inner Mongolia in an attempt to identify biomarkers useful for assessing health risk resulting from chronic arsenic exposure. The study subjects included 19 high As-exposed individuals (9 smokers and 10 nonsmokers) with hyperkeratosis and/or hyperpigmentation and 13 low or no exposure individuals (4 smokers and 9 nonsmokers). Water samples immediately collected from wells and after storage in tanks in homes prior to consumption were analyzed for As(III) and As(V). Urine samples were collected and analyzed for Inorganic As, MMA, and DMA by HPLC/HGAFS. Exfoliated epithelia, including buccal, sputum and urothelial cells, from the subjects were assayed for micronuclei and DNA fragmentation using DNA ladder and TUNEL assay. The results from buccal cells showed a mean frequency of 2.21? 0.36 MN/1000 cells in the As-exposed group (As 506.0?20.7 g/L) and 0.65?0.21 MN/1000 cells in the controls (As 4.4?1.0 g/L). The difference is statistically significant (p<0.01). Without the smokers, induction levels of the MN remain significantly elevated over controls (p<0.01). Similar arsenic-dependent results in MN levels were observed in sputum and urothelial cells. In the DNA ladder assay, 89% (17/19) of the As-exposed group showed the presence of <100 bp fragments, in contrast to 15% (2/13) in the controls. The difference is statistically significant ( p<0.0001). With one exception, all the smokers from the control group did not show <100 bp DNA fragmentation. The mean frequency of positive cells in the TUNEL assay was much higher in the exposed group (15%) than in the control group (2%) (p<0.01). This study elucidated that chronic exposure to high concentrations of arsenic increased risk for apoptosis and chromosome damage. Micronuclei and DNA fragmentation may be useful in assessing genotoxicity of arsenic. Currently, we are conducting a large study to evaluate if these biomarkers can be useful in assessing genotoxic effects at low doses. (This abstract does not necessarily reflect EPA policy.)
CORRESPONDING AUTHORS: Judy L. Mumford, Ph.D. National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711, USA