摘要:

AbstractPolycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants. Human exposure occurs through diet, smoking, and polluted air. In some groups of workers exposed to PAHs, epidemiological studies have revealed an increased mortality risk for neoplasms. This paper reviews the principal methods that have been developed recently for the detection of PAH adducts to white blood cell DNA and blood proteins (hemoglobin, albumin) and summarizes observations made on occupationally exposed subjects.

ISSN:1040-8444    

DOI:10.3109/10408449309117113

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractThe number of studies in the research field of antimutagenesis is increasing. The aims of many of these studies are preventing genetic hazards from environmental mutagens and elucidating the process of mutagenesis. Some naturally occuring flavorings such as vanillin, cinnamaldehyde, and coumarin have been reported to inhibit mutagenesis induced by mutagens in bacterial and mammalian cells. These flavorings are considered to act as antimutagens by modifying DNA replication and/or DNA repair systems after cellular DNA was damaged by mutagens. A factor that suppresses mutagenicity in a given situation, however, sometimes exerts enhancing effects when the endpoints investigated or the test conditions used are varied. This makes the evaluation of antimutagenic factors complicated. Different modifying effects of the above-mentioned flavorings observed in various test systems for genotoxicity are discussed, based on their proposed mechanisms.

ISSN:1040-8444    

DOI:10.3109/10408449309117114

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractVitamin E (α-tocopherol), the principal chain-breaking antioxidant in biological membranes, prevents toxicant- and carcinogen-induced oxidative damage by trapping reactive oxyradicals. Althoughα-tocopherol antioxidant reactions appear to be not under direct metabolic control,α-tocopherol may function through redox cycles, which deliver reducing equivalents for antioxidant reactions and link antioxidant function to cellular metabolism. This review describes the antioxidant chemistry ofα-tocopherol and evaluates the experimental evidence for the linkage ofα-tocopherol turnover to cellular metabolism through redox cycles. Numerousin vitroexperiments demonstrate antioxidant synergism betweenα-tocopherol and ascorbate, reduced glutathione, NADPH, and cellular electron transport proteins. Nevertheless, evidence that a one-electron redox cycle regeneratesα-tocopherol from the tocopheroxyl radical is inconclusive. The difficulty of separating tocopheroxyl recycling from direct antioxidant actions of other antioxidants has complicated interpretation of the available data. A two-electron redox cycle involvingα-tocopherol oxidation to 8a-substituted tocopherones followed by tocopherone reduction toα-tocopherol may occur, but would require enzymatic catalysisin vivo. Metabolism of antioxidant-inactiveα-tocopheryl esters releasesα-tocopherol, whereas reductive metabolism ofα-tocopherylquinone, anα-tocopherol oxidation product, yieldsα-tocopherylhydroquinone, which also may provide antioxidant protection.

ISSN:1040-8444    

DOI:10.3109/10408449309117115

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractCertain metals, and many metal-based compounds, are inherently toxic, and their presence in occupational and environmental settings raises appropriate questions concerning human exposure. Contact of these materials with the skin represents an important route of exposure, which is not well characterized. The purpose of this review, therefore, is to assemble the available, useful information pertinent to risk assessment following dermal contact.Specifically, we summarize here: (1) data relevant to the qualitative and (where possible) quantitative evaluation of metal compound permeation through the skin; (2) the role of each metal in metabolism, particularly with respect to the skin, and the potentially toxic effects that may result from dermal contact; and (3) the immunological characteristics (including allergenicity) of the metals and their derivatives.In total, information on 31 metals has been reviewed. It is clear that many diverse factors determine the ability of metal-based species to permeate biological membranes, not all of which have been fully defined. Therefore, considerably more experimentation, targeted at the development of high-quality transport data, will be required before the specification of practically useful structure-activity relationships are possible.

ISSN:1040-8444    

DOI:10.3109/10408449309117116

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor