TY - JOUR AB - Adverse health effects driven by airborne particulate matter (PM) are mainly associated with reactive oxygen species formation, pro-inflammatory effects, and genome instability. Therefore, a better understanding of the underlying mechanisms is needed to evaluate health risks caused by exposure to PM. The aim of this study was to compare the genotoxic effects of two oxidizing agents (menadione and 3-chloro-1,2-propanediol) with three different reference PM (fine dust ERM-CZ100, urban dust SRM1649, and diesel PM SRM2975) on monocytic THP-1 and alveolar epithelial A549 cells. We assessed DNA oxidation by measuring the oxidized derivative 8-hydroxy-2'-deoxyguanosine (8-OHdG) following short and long exposure times to evaluate the persistency of oxidative DNA damage. Cytokinesis-block micronucleus cytome assay was performed to assess chromosomal instability, cytostasis, and cytotoxicity. Particles were characterized by inductively coupled plasma mass spectrometry in terms of selected elemental content, the release of ions in cell medium and the cellular uptake of metals. PM deposition and cellular dose were investigated by a spectrophotometric method on adherent A549 cells. The level of lipid peroxidation was evaluated via malondialdehyde concentration measurement. Despite differences in the tested concentrations, deposition efficiency, and lipid peroxidation levels, all reference PM samples caused oxidative DNA damage to a similar extent as the two oxidizers in terms of magnitude but with different oxidative DNA damage persistence. Diesel SRM2975 were more effective in inducing chromosomal instability with respect to fine and urban dust highlighting the role of polycyclic aromatic hydrocarbons derivatives on chromosomal instability. The persistence of 8-OHdG lesions strongly correlated with different types of chromosomal damage and revealed distinguishing sensitivity of cell types as well as specific features of particles versus oxidizing agent effects. In conclusion, this study revealed that an interplay between DNA oxidation persistence and chromosomal damage is driving particulate matter-induced genome instability. AU - Cao, X. AU - Padoan, S. AU - Binder, S. AU - Bauer, S. AU - Orasche, J. AU - Rus, C.M.* AU - Mudan, A.* AU - Huber, A. AU - Kuhn, E. AU - Oeder, S. AU - Lintelmann, J. AU - Adam, T. AU - Di Bucchianico, S. AU - Zimmermann, R. C1 - 64142 C2 - 51882 TI - A comparative study of persistent DNA oxidation and chromosomal instability induced in vitro by oxidizers and reference airborne particles. JO - Mutat. Res. - Gen. Tox. Environ. Mutag. VL - 874-875 PY - 2022 SN - 1383-5718 ER - TY - JOUR AB - Recent studies suggest that every year worldwide about a million patients might be exposed to doses of the order of 100 mGy of low-LET radiation, due to recurrent application of radioimaging procedures. This paper presents a synthesis of recent epidemiological evidence on radiation-related cancer risks from low-LET radiation doses of this magnitude. Evidence from pooled analyses and meta-analyses also involving epidemiological studies that, individually, do not find statistically significant radiation-related cancer risks is reviewed, and evidence from additional and more recent epidemiological studies of radiation exposures indicating excess cancer risks is also summarized. Cohorts discussed in the present paper include Japanese atomic bomb survivors, nuclear workers, patients exposed for medical purposes, and populations exposed environmentally to natural background radiation or radioactive contamination. Taken together, the overall evidence summarized here is based on studies including several million individuals, many of them followed-up for more than half a century. In summary, substantial evidence was found from epidemiological studies of exposed groups of humans that ionizing radiation causes cancer at acute and protracted doses above 100 mGy, and growing evidence for doses below 100 mGy. The significant radiation-related solid cancer risks observed at doses of several 100 mGy of protracted exposures (observed, for example, among nuclear workers) demonstrate that doses accumulated over many years at low dose rates do cause stochastic health effects. On this basis, it can be concluded that doses of the order of 100 mGy from recurrent application of medical imaging procedures involving ionizing radiation are of concern, from the viewpoint of radiological protection. AU - Rühm, W. AU - Laurier, D.* AU - Wakeford, R.* C1 - 63912 C2 - 51726 TI - Cancer risk following low doses of ionising radiation – Current epidemiological evidence and implications for radiological protection. JO - Mutat. Res. - Gen. Tox. Environ. Mutag. VL - 873 PY - 2022 SN - 1383-5718 ER - TY - JOUR AB - In conventional experiments on biological effects of radiation types of diverse quality, micrometer-scale double-strand break (DSB) clustering is inherently interlinked with clustering of energy deposition events on nanometer scale relevant for DSB induction. Due to this limitation, the role of the micrometer and nanometer scales in diverse biological endpoints cannot be fully separated. To address this issue, hybrid human-hamster AL cells have been irradiated with 45 MeV (60 keV/μm) lithium ions or 20 MeV (2.6 keV/μm) protons quasi-homogeneously distributed or focused to 0.5 × 1 μm2 spots on regular matrix patterns (point distances up to 10.6 × 10.6 μm), with pre-defined particle numbers per spot to provide the same mean dose of 1.7 Gy. The yields of dicentrics and their distribution among cells have been scored. In parallel, track-structure based simulations of DSB induction and chromosome aberration formation with PARTRAC have been performed. The results show that the sub-micrometer beam focusing does not enhance DSB yields, but significantly affects the DSB distribution within the nucleus and increases the chance to form DSB pairs in close proximity, which may lead to increased yields of chromosome aberrations. Indeed, the experiments show that focusing 20 lithium ions or 451 protons per spot on a 10.6 μm grid induces two or three times more dicentrics, respectively, than a quasi-homogenous irradiation. The simulations reproduce the data in part, but in part suggest more complex behavior such as saturation or overkill not seen in the experiments. The direct experimental demonstration that sub-micrometer clustering of DSB plays a critical role in the induction of dicentrics improves the knowledge on the mechanisms by which these lethal lesions arise, and indicates how the assumptions of the biophysical model could be improved. It also provides a better understanding of the increased biological effectiveness of high-LET radiation. AU - Schmid, T.E.* AU - Friedland, W. AU - Greubel, C.* AU - Girst, S.* AU - Reindl, J.* AU - Siebenwirth, C.* AU - Ilicic, K.* AU - Schmid, E.* AU - Multhoff, G. AU - Schmitt, E. AU - Kundrát, P. AU - Dollinger, G.* C1 - 46650 C2 - 37643 SP - 30-40 TI - Sub-micrometer 20 MeV protons or 45 MeV lithium spot irradiation enhances yields of dicentric chromosomes due to clustering of DNA double-strand breaks. JO - Mutat. Res. - Gen. Tox. Environ. Mutag. VL - 793 PY - 2015 SN - 1383-5718 ER - TY - JOUR AB - A computational model of radiation-induced chromosome aberrations in human cells within the PARTRAC Monte Carlo simulation framework is presented. The model starts from radiation-induced DNA damage assessed by overlapping radiation track structures with multi-scale DNA and chromatin models, ranging from DNA double-helix in atomic resolution to chromatin fibre loops, heterochromatic and euchromatic regions, and chromosome territories. The repair of DNA double-strand breaks via non-homologous end-joining is followed. Initial spatial distribution and complexity, diffusive motion, enzymatic processing, synapsis and ligation of individual DNA ends from the breaks are simulated. To enable scoring of different chromosome aberration types resulting from improper joining of DNA fragments, the repair module has been complemented by tracking the chromosome origin of the ligated fragments and the positions of centromeres. The modelled motion of DNA ends has sub-diffusive characteristics and corresponds to measured chromatin mobility within time-scales of a few hours. The calculated formation of dicentrics after photon and α-particle irradiation in human fibroblasts is compared to experimental data (Cornforth et al., 2002, Radiat Res 158, 43). The predicted yields of dicentrics overestimate the measurements by factors of five for γ-rays and two for α-particle irradiation. Nevertheless, the observed relative dependence on radiation dose is correctly reproduced. Calculated yields and size distributions of other aberration types are discussed. The present work represents a first mechanistic approach to chromosome aberrations and their kinetics, combining full track structure simulations with detailed models of chromatin and accounting for the kinetics of DNA repair. AU - Friedland, W. AU - Kundrát, P. C1 - 26142 C2 - 32090 SP - 213-223 TI - Track structure based modelling of chromosome aberrations after photon and alpha-particle irradiation. JO - Mutat. Res. - Gen. Tox. Environ. Mutag. VL - 756 IS - 1 PB - Elsevier Science PY - 2013 SN - 1383-5718 ER - TY - JOUR AU - Attia, S.M. AU - Schmid, T.E. AU - Badary, O.A.* AU - Hamada, F.M.* AU - Adler, I.-D. C1 - 21955 C2 - 20473 SP - 1-13 TI - Molecular cytogenetic analysis in mouse sperm of chemically induced aneuploidy : Studies with topoisomerase II inhibitors. JO - Mutat. Res. - Gen. Tox. Environ. Mutag. VL - 520 PY - 2002 SN - 1383-5718 ER - TY - JOUR AB - Aneuploidy induction in male germ cells of mice and men after chronic exposure to diazepam (DZ: CAS 439-14-5; Valium(R)) was assessed by multicolor fluorescence in situ hybridization (FISH). DZ, a widely administered sedative and muscle relaxant, was proposed to act as an aneugen by disturbing spindle function in various assay systems. Male mice were treated by oral intubation with 3 mg/kg DZ once or daily for 14 consecutive days. At 22 days after the last treatment, epididymal sperm were collected from the caudae epididymes. Evaluation of aneuploid and diploid sperm (10,000 sperm per animal) was performed by multicolor FISH employing DNA probes specific for chromosomes X, Y, and 8 simultaneously. We found a significant increase in the frequency of disomy 8 in subchronically DZ-treated mice when compared to the concurrent solvent control group (2.4-fold; P < 0.01), while no increase was detected for sex-chromosome hyperhaploidies. No effect was seen when mice were treated with a single dose (3 mg/kg DZ). In a parallel human approach, two men were evaluated who chronically ingested >0.3 mg/kg/d DZ for more than 6 months. Multicolor FISH was applied to human sperm probing for chromosomes X, Y, and 13. Frequencies for sperm with disomy 13, disomy X, and total sex-chromosomal disomies were found to be elevated among the two subjects after chronic DZ-exposure compared to control subjects. In conclusion, the results indicate that diazepam acts as an aneugen during meiosis in male spermatogenesis, both in mice and humans. The quantitative comparison indicates that humans may be at least 10 times more sensitive than mice for aneuploidy induction by DZ during male meiosis. AU - Baumgartner, A. AU - Schmid, T.E. AU - Schuetz, C.G.* AU - Adler, I.-D. C1 - 9980 C2 - 22294 SP - 11-19 TI - Detection of aneuploidy in rodent and human sperm by multicolor FISH after chronic exposure to diazepam. JO - Mutat. Res. - Gen. Tox. Environ. Mutag. VL - 490 PB - Elsevier PY - 2001 SN - 1383-5718 ER - TY - JOUR AB - The study was aimed at determining the genotoxic potential of extractable organic matter (EOM) from ambient air particles PM10 (<10 micrometer) using mammalian cells in culture as test system. Air samples were collected in the course of summer and winter periods in two regions of the Czech Republic representing low and high levels of air pollution, the districts of industrial Teplice and rural Prachatice, respectively. EOM was fractionated by acid-base partitioning and silica gel column chromatography. Aliquots of fractions were incubated with cultured hepatocytes derived from male rats or Chinese hamster lung V79NH cells expressing nitroreductase activity but virtually no cytochrome P450 activity. DNA adduct levels were analyzed by 32P-postlabeling using butanol extraction for adduct enrichment. In hepatocytes, crude extracts caused the formation of substantial amounts of DNA reactive material being detectable in a broad diagonal radioactive zone (DRZ) in the chromatograms. Highest DNA adduct levels were found in the aromatic fractions and slightly polar fractions which contain most of the polycyclic aromatic hydrocarbons (PAH) and nitro-substituted PAH (nitro-PAH), respectively, comprising 75-90% of total adducts. This partitioning was independent of the sampling period and locality. In agreement with the higher average ambient air concentrations of PAH in the winter than the summer, 3-4-fold higher DNA adduct levels were detected in extracts sampled in the winter. Calculated on the basis of EOM/m(3), DNA adduct levels of samples collected in winter period were 10-fold higher than those collected in the summer period and 2-fold higher in Teplice than in Prachatice. Pretreatment of hepatocytes with 2,3,7,8-tetrachlorodibenzo-p-dioxin decreased DNA binding by 50-75%. In contrast to the findings in hepatocytes, in V79NH cells about 80% of the DNA adducts were caused by material in the slightly polar fractions appearing as distinct spots in the radiochromatograms. Seasonal variation of DNA adducts in V79NH cells was greater than variation between localities. Our results suggest that PAH as well as nitro-PAH are the main contributors to the genotoxicity of EOM derived from both industrial and rural areas. The results, furthermore, indicate that analysis of DNA adducts in mammalian cells in culture offers a suitable method for monitoring the genotoxicity of complex mixtures of environmental chemicals. AU - Topinka, J. AU - Schwarz, L.R. AU - Wiebel, F.J. AU - Cerná, M.* AU - Wolff, T. C1 - 23951 C2 - 31411 SP - 83-93 TI - Genotoxicity of urban air pollutants in the Czech Republic. Part II. DNA adduct formation in mammalian cells by extractable organic matter. JO - Mutat. Res. - Gen. Tox. Environ. Mutag. VL - 469 IS - 1 PB - Elsevier Science PY - 2000 SN - 1383-5718 ER - TY - JOUR AB - 2-Nitropropane (2-NP) is a genotoxic hepatocarcinogen in rats. The genotoxicity of the compound has been attributed to a sulfotransferase-mediated formation of DNA-reactive species from the anionic form of 2-NP, propane 2-nitronate (P2N). Several observations have suggested that sulfotransferases (SULTs) 1A1 and/or 1C1 may be important in the activation of P2N to a genotoxicant in rat liver, but a definite proof is lacking. In order to identify the sulfotransferase(s) of rat liver that are capable of activating P2N, we have investigated the genotoxicity of P2N in various V79-derived cell lines engineered for expression of individual forms of rat hepatic sulfotransferases. Genotoxicity was assessed by measuring the induction of DNA repair synthesis. 1-Hydroxymethylpyrene (HMP), which is metabolically activated by most sulfotransferases, served as a positive control. Neither P2N nor HMP induced DNA repair in the parental V79-MZ cells, which do not show any sulfotransferase activity. P2N was also inactive in V79-rHSTa and V79-rHST20 cells, which express specific hydroxysteroid sulfotransferases. By contrast, a clear and concentration-dependent induction of repair synthesis by P2N was observed in V79-rPST-IV and V79-rST1C1 cells, which express rat SULT1A1 and SULT1C1, respectively. HMP was genotoxic in all sulfotransferase-expressing cell lines. Acetone oxime (AO), the tautomeric form of the first reduction product of 2-NP, 2-nitrosopropane, was inactive in all cell lines. The results corroborate the essential role of sulfotransferases in the metabolic activation of P2N to genotoxic products and identify two rat sulfotransferases which are capable of catalyzing the activation step. AU - Andrae, U. AU - Kreis, P. AU - Coughtrie, M.W.* AU - Pabel, U.* AU - Meinl, W.* AU - Bartsch, I.* AU - Glatt, H.* C1 - 23973 C2 - 31424 SP - 191-197 TI - Activation of propane 2-nitronate to a genotoxicant in V79-derived cell lines engineered for the expression of rat hepatic sulfotransferases. JO - Mutat. Res. - Gen. Tox. Environ. Mutag. VL - 439 IS - 2 PB - Elsevier Science PY - 1999 SN - 1383-5718 ER - TY - JOUR AU - Adler, I.-D. AU - Bootman, J.* AU - Favor, J. AU - Hook, G.* AU - Schriever-Schwemmer, G. AU - Welzl, G. AU - Whorton, E.* AU - Yoshimura, I.* AU - Hayashi, M.* C1 - 20790 C2 - 18840 SP - 19-30 TI - Recommendations for statistical designs of in vivo mutagenicity tests with regard to subsequent statistical analysis. JO - Mutat. Res. - Gen. Tox. Environ. Mutag. VL - 417 PY - 1998 SN - 1383-5718 ER - TY - JOUR AB - The transgenic Muta(TM)Mouse in vivo mutagenesis assay was employed to determine the activity of acrylamide and ethylnitrosourea in liver and germ cells after 3, 10 and 100 days following treatment. Each cell of the Muta(TM)Mouse carries 80 copies of the lambda gt10 phage including the bacterial lacZ gene, which act as the target gene for the mutagenesis assay. Groups of Muta(TM)Mice were given a single intraperitoneal injection of 80 or 160 mg/kg ethylnitrosourea or 50 or 100 mg/kg acrylamide. The tissues were prepared 3, 10 or 100 days post treatment. The liver genomic DNA was extracted with the manufacturer's standard protocoll, while the genomic germ cell DNA was extracted with 4 different methods due to problems encountered in DNA yields and packaging efficiency. The mutation analysis of the lacZ gene was carried out by the positive selective assay method [Gossen et al. (1989) Proc. Natl. Acad. Sci. USA, 86, 7971-7975; Dean and Myhr (1994) Mutagenesis, 9, 183-185]. There was a slight increase due to treatment of the observed mutation frequencies in the acrylamide liver group for all three assay times. From the day 3 group to the day 100 group a time dependent decrease in all the absolute mutant frequencies was detectable. The ethylnitrosourea liver group showed a time - and dose-dependent increase in the mutant frequencies from day 3 to day 100. No meaningfull results were obtained for the germ cell tissue assays due to the low amount of genomic DNA extracted which was not packageable in the lambda lacZ assay. At present for the mutagenesis assay of isolated spermatozoa in our laboratory we would be forced to pool tissues from animals to obtain enough DNA for an assay. Since 'jackpot'-animals may exist [Heddle et al. (1992) Mutation Res., 272, 195-203] the individual animals of such a pooled analysis group must be tested before pooling. AU - Krebs, O. AU - Favor, J. C1 - 33157 C2 - 35529 SP - 239-248 TI - Somatic and germ cell mutagenesis in lambda lacZ transgenic mice treated with acrylamide or ethylnitrosourea. JO - Mutat. Res. - Gen. Tox. Environ. Mutag. VL - 388 IS - 2-3 PY - 1997 SN - 1383-5718 ER -