TOXICOLOGICAL PROFILE FOR CHROMIUM - Davidborowski.com

CHROMIUM 2262. HEALTH EFFECTSMutti 1988). The urine of chromium(VI) exposed workers in a chromate production plant containedhigher levels of a brush border protein and of retinol-binding protein in the urine than did nonexposedcontrols (Mutti et al. 1985a). In a study of currently exposed chrome platers, ex-chrome platers, andreferent groups of nonexposed workers, the urinary levels of β 2 -microglobulin were significantly higher(p=0.045), and elevated levels occurred more often in the presently exposed groups compared with itsage-matched control group. The levels of β 2 -microglobulin in the urine of the ex-chrome platers,however, were not different than those of its age-matched control group (Lindberg and Vesterberg1983b). Another study of hard chrome electroplaters found a higher prevalence of workers with elevatedN-acetyl-β-glucosamindase levels (Liu et al. 1998). Although this study also found higher levels ofβ 2 -microglobulins in the chrome plater, the prevalence of elevated values was not significantly increased.The presence of low molecular weight proteins, such as retinol binding protein, antigens, orß 2 -microglobulin in the urine is believed to be an early indication of kidney dysfunction. The lack of asignificant difference in the ex-chrome platers compared with the control group suggests that thechromium-induced kidney damage may be reversible. Cell culture and cell free studies discussed inSection 2.4.2 demonstrated that chromium forms protein-DNA crosslinks and adducts with DNA, and thatthese end points may be potentially useful biological markers indicating the possibility of genotoxiceffects or cancer in humans exposed to chromium. However, no increases in protein-DNA crosslinkswere observed in white cells from volunteers that were exposed to chromium(VI) in drinking water(Kuykendall et al. 1996).The possibility of using an immune-function assay as a potential biomarker for humans exposed tochromium has been examined (Snyder et al. 1996). Isolated mononuclear cells from 46 individuals wholived and/or worked in areas in northern New Jersey at sites contaminated by chromium processing werestimulated by pokeweed mitogen. Rates of stimulated cell growth and production of interleukin 6 (IL-6)were measured and compared to a control population which lived/worked in uncontaminated areas. Therewas no significant increase in mitogen stimulation between people from contaminated areas and controls,but there was a significant (36%) decrease in the levels of IL-6 in monocytes in the chromium exposedgroup. IL-6 is an important cytokine that is involved in the T-cell helper pathway of antibody production.The significance of the lower levels may lead to decreased levels of antibody production.The effects of chromium(III) chloride, sodium chromate(VI) and potassium chromate(VI) on proliferationof mononuclear leukocytes obtained from chromium sensitive individuals (confirmed with positive patchtests) was compared to nonsensitive controls (confirmed by negative patch tests) (Räsänen et al. 1991).Isolated cells were exposed to 25–50 µg/mL culture medium of chromium(III) chloride and to 0.025 to