BACKGROUND Hexavalent chromium [Cr(VI)] is recognized as a human carcinogen via inhalation. However, the molecular mechanisms by which Cr(VI) causes cancers are not well understood. OBJECTIVES We evaluated cyclooxygenase-2 (COX-2) expression and the signaling pathway leading to this induction due to Cr(VI) exposure in cultured cells. METHODS We used the luciferase reporter assay and Western...

Several adverse health effects, including irritant and allergic contact dermatitis, have been reported among workers who are occupationally exposed to chromium-containing compounds. Human dermal fibroblasts were used as an in vitro experimental model to study the potential mechanisms underlying hexavalent chromium [Cr(VI)]-induced dermal toxicity. Exposure of the fibroblasts to 5 microM Cr(VI) ...

Hexavalent chromium [Cr(VI)] is a well-known human carcinogen associated with the incidence of lung cancer. Although overproduction of reactive oxygen species (ROS) has been suggested to play a major role in its carcinogenicity, the mechanisms of Cr(VI)-induced ROS production remain unclear. In this study, we investigated the role of NADPH oxidase (NOX), one of the major sources of cellular ROS...

Chromium(VI) is a known human carcinogen which requires intracellular reduction for activation. Ascorbate (vitamin C) has been reported to function as a major reductant of Cr(VI) in animals and cell culture systems. The reaction of Cr(VI) with varying concentrations of ascorbate was studied under physiological conditions in vitro in order to determine the types of reactive intermediates produce...

Cr(VI) causes severe kidney damage. The patient's renal function could gradually recover by spontaneous kidney regeneration. The molecular effect of Cr(VI) on recovery of kidney cells, however, has not been clearly elucidated. Here we show that Cr(VI) induces expression of mesenchymal and stem cell markers, cell markers, such as paxillin, vimentin, α-SMA, nanog, and CD133 of HK-2 cells. Moreove...

Hexavalent chromium, Cr(VI), is an environmental toxicant and is associated with hepatotoxicity. However, very little is known about the intracellular antioxidant defense mechanism against Cr(VI)-induced cytotoxicity in hepatocytes. In the present study, we cultured human liver (HepG2) cells in the absence or presence of Cr(VI) and determined its effect on cellular oxidative stress, mitochondri...

This study proved that vermiculite, a natural occurring mineral, can effectively remove and stabilize Cr(VI) from fine ferrochrome dust leachate. Batch adsorption studies were carried out to determine the effect of pH, contact time and adsorbent dose on the removal of Cr(VI). The process was found to be highly pH dependent. The optimum conditions for the Cr(VI) removal are at a pH of 1.5, conta...

the potential of heat inactivated saccharomyces cerevisiae in the bioremoval and reduction ofcr (vi) ions from wastewaters was evaluated in terms of metal uptake in time and at equilibrium, andbiosorption efficiency, by varying ph, biosorbent doses, contact time and temperature, in batch mode. during the sorption process, the heat inactivated biomass of the yeast saccharomyces cerevisiae is cap...

rinking water utilities face the challenge of addressing emerging water quality concerns to ensure adequate protection of public health, sometimes without final federal or state drinking water regulations. Total chromium, i.e., trivalent chromium [Cr(III)] plus hexavalent chromium [Cr(VI)], has been regulated by national drinking water regulations since 1975. The federal regulatory maximum cont...

High levels of hexavalent chromium (Cr(VI)) in groundwater are typically attributed to anthropogenic sources. However, scientific reports over the last decade have demonstrated that relatively high levels of Cr(VI) in groundwater may also be due to natural processes. Cr(VI) is among the most significant groundwater contaminants, since it is a potential carcinogenic compound that is commonly fou...