The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Human exposure to methylating agents appears to be widespread, as indicated by the frequent occurrence of methylated DNA adducts in human DNA. The high incidence of methylated DNA adducts even in humans thought not to have suffered extensive exposure to environmental methylating agents implies that chemicals of endogenous origin, probably N-nitroso compounds such as the strongly carcinogenic N-nitrosodimethylamine...
More emphasis should be placed upon using biomarkers to address potential health risk among populations exposed to high concentrations of environmental toxicants. Among these studies, those which integrate exposure measurements with analyses of validated biomarkers may provide more reliable information for risk assessment and disease prevention. We have used a multidisciplinary approach to elucidate...
The cytogenetic endpoints in peripheral blood lymphocytes: chromosomal aberrations (CA), sister chromatid exchange (SCE) and micronuclei (MN) are established biomarkers of exposure for mutagens or carcinogens in the work environment. However, it is not clear whether these biomarkers also may serve as biomarkers for genotoxic effects which will result in an enhanced cancer risk. In order to assess...
We report here results on forward mutation induction (recessive lethal mutations, RL) in Drosophila spermatozoa and spermatids by the three 1,2-alkyl-epoxides ethylene oxide (EO), propylene oxide (PO) and butylene oxide (BO), at doses ranging from 47 to 24,000 ppm h for EO, 375 to 48,000 ppm h for PO, and 24,000 to 91,200 ppm h for BO. The results indicate for EO mutation induction at doses 500-fold...
Chromosomal instability in proliferating mammalian cells is characterized by a persistent increase of chromosomal aberrations and rearrangements occurring de novo during successive cell generations. Recent results from many laboratories using a variety of cells and cytogenetic end points show that this phenotype can be induced by low as well as high LET irradiation. A typical feature of chromosomal...
Transgenic systems, both cell lines and mice with gain or loss of function, are being used in order to modulate the expression of DNA repair proteins, thus allowing to assess their contribution to the defense against genotoxic mutagens and carcinogens. In this review, questions have been addressed concerning the use of transgenic systems in elucidating critical primary DNA lesions, their conversion...
Extrapolation of health risks from high to low doses has received a considerable amount of attention in carcinogenic risk assessment over decades. Fitting statistical dose-response models to experimental data collected at high doses and use of the fitted model for estimating effects at low doses lead to quite different risk predictions. Dissatisfaction with this procedure was formulated both by toxicologists...
The synthetic monomer 1,3-butadiene and its metabolites have been reviewed in various in vitro and in vivo metabolic studies and in genetic toxicology assays. The species differences have been compared.
The shape of a carcinogen dose-cancer incidence curve is discussed as the result of a superposition of dose-response relationships for various effects of the carcinogen on the process of carcinogenesis. Effects include direct DNA damage, e.g., by covalent binding, indirect DNA damage, e.g., by increased formation of reactive oxygen species or interaction with DNA replication or chromosome integrity...
Data on transgenic rodent mutagenicity of five human carcinogens were summarised and compared with the results from rodent carcinogenicity studies. Four out of five carcinogens showed mutagenic activity already at daily dose levels which induced cancer in long-term rodent bioassays in at least one target tissue of carcinogenesis. In several of these studies, even single dose applications were sufficient...
Ethylnitrosourea is the most efficient chemical mutagen in spermatogonial stem cells of the mouse and its mutagenic activity has been intensively studied. The pertinent specific-locus mutation test results for a discussion of low dose-effect studies have been summarized and indicate: (1) A threshold dose response best characterizes the relationship between dose and mutation rate. (2) The reduced effectiveness...
Using flow cytometric automation of the mouse in vivo, micronucleus assay increases the sensitivity of the test. This is achieved through a very large increase in the number of cells scored, by a factor of 100x, which in turn greatly reduces the sampling error. With this method, dose-response relationships of in vivo micronucleus induction for four model agents mitomycin C (MMC), diepoxybutane (DEB),...
DNA adducts associated with oxidative stress are believed to involve the formation of endogenous reactive species generated by oxidative damage and lipid peroxidation. Although these adducts have been reported in several human tissues by different laboratories, a comparison of the levels of these adducts in the same tissue samples has not been carried out. In this study, we isolated DNA from the pancreas...
The restriction site mutation (RSM) assay (see Steingrimsdottir et al. [H. Steingrimsdottir, D. Beare, J. Cole, J.F.M. Leal, T. Kostic, J. Lopez-Barea, G. Dorado, A.R. Lehmann, Development of new molecular procedures for the detection of genetic alteration in man, Mutat. Res. 353 (1996) pp. 109-121] for a review) has been developed as a genotypic mutation detection system capable of identifying mutations...
Spontaneous mutations seem to be caused almost entirely by endogenous lesions. The pattern of these lesions along a gene represents an equilibrium between damage and repair. A pattern can be measured using ligation-mediated PCR (polymerase chain reaction) and a large chronic dose of a suspected endogenous mutagen. A study using dimethylsulfate-induced 7 me Guanine lesions indicates that...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.