Journal ArticleDOI
Metabolic deactivation of hexavalent chromium mutagenicity.
F.L. Petrilli,Silvio De Flora +1 more
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TLDR
Hexavalent chromium compounds were found to be mutagenic for his − strains of S. typhimurium by inducing both frameshifts and base-pair substitutions, but addition of either microsomal fractions from rat liver or of human erythrocyte lysates resulted in a complete loss of mutagenicity.Abstract:
Hexavalent chromium compounds (sodium dichromate, potassium chromate, chromic acid, basic zinc chromate and basic lead chromate) were found to be mutagenic for his − strains of S. typhimurium by inducing both frameshifts and base-pair substitutions. However, addition of either microsomal fractions from rat liver or of human erythrocyte lysates resulted in a complete loss of mutagenicity. As confirmed by chemical analysis, reversal of mutagenicity could be ascribed to reduction of the metal to the inactive trivalent form through a simple oxido-reductive reaction. In fact, reducing agents (ascorbic acid and sodium sulfite) and metabolites (GSH, DPNH and TPNH, either directly tested or obtained by mixing G6PD with S-9 mix) prevented hexavalent chromium mutagenicity, whereas an oxidizing agent (potassium permanganate) totally inhibited reversal of mutagenicity by liver and erythrocyte preparations. Enzymic conversion appeared to be involved in deactivation processes through a large production of TPNH via the hexose monophosphate oxidative pathway and other ancillary systems. On the other hand, microsomal preparations from rat lung displayed an extremely poor inactivating effect on chromium mutagenicity, and those from rat muscle, as well as human serum or plasma, were ineffective. These findings could bear relevance for the elective localization of chromium-induced tumors in human lung and could account for the results of animal carcinogenicity tests, which generally showed the development of tumors, but only at implant sites.read more
Citations
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A Critical Assessment of Chromium in the Environment
TL;DR: In this paper, the authors reviewed the emissions, environmental fate and transport, analytical chemistry, uptake and metabolism, toxicology, and human epidemiology of chromium, and found that chromium is unique among regulated toxic elements in the environment in that different species of the chromium are regulated in different ways, in contrast to other toxic elements where the oxidation state is not distinguished.
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Mechanisms of Chromium Carcinogenicity and Toxicity
TL;DR: The chemical nature of chromium compounds and how these properties impact upon the interactions ofchromium with cellular and genetic targets, including animal and human hosts, are discussed.
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Genotoxicity of chromium compounds. A review.
TL;DR: This article reviews approximately 700 results reported in the literature with 32 chromium compounds assayed in 130 short-term tests, using different targets and/or genetic end-points, to provide useful information for predicting and interpreting the peculiar patterns of Cr(VI) carcinogenicity.
Journal ArticleDOI
Phytoremediation of heavy metals: mechanisms, methods and enhancements
S. Muthusaravanan,N. Sivarajasekar,J. S. Vivek,T. Paramasivan,Mu. Naushad,J. Prakashmaran,V. Gayathri,Omar K. Al-Duaij +7 more
TL;DR: In this paper, a review of the methods and mechanisms involved in phytoremediation of heavy metals, and enhancement processes is presented, which is based upon several processes such as phytodegradation, phytovolatilization, phytoaccumulation, and phyttoextraction.
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Threshold mechanisms and site specificity in chromium(VI) carcinogenesis
TL;DR: Experimental and epidemiological data, and the underlying mechanisms, point to the occurrence of thresholds in chromium(VI) carcinogenesis, as quantified in human body compartments.
References
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Journal Article
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Methods for detecting carcinogens and mutagens with the salmonella/mammalian-microsome mutagenicity test
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Seymour J. Gray,Kenneth Sterling +1 more
TL;DR: The present report is concerned with a new biological tracer, radioactive chromium (Cr51), which is bound by the red cells and plasma proteins, and both anionic hexavalent and cationic trivalent states of the element have been studied.
Journal ArticleDOI
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