scholarly journals Genotoxicity and DNA repair indicative in blood cells after occupational exposure to ionizing radiation

10.3823/1992 ◽  
2016 ◽  
Author(s):  
Ronald Gerard Silva ◽  
Marcus Vinícius Oliveira Barros Alencar ◽  
Jadson Silva Teixeira ◽  
Reyca Rodrigues e Silva ◽  
Márcia Fernanda Correia Jardim Paz ◽  
...  
Keyword(s):  
Dna Repair ◽  
Occupational Exposure ◽  
Ionizing Radiation ◽  
Blood Cells

scholarly journals Influence of Polymorphisms of DNA Repair and GST Genes on Genotoxic Damage and Mutagen Sensitivity in Workers Occupationally Exposed to Very Low Doses of Ionizing Radiation

2019 ◽  
Vol 9 (23) ◽  
pp. 5175 ◽  
Author(s):  
Stufano ◽  
Chiarappa ◽  
Bagnulo ◽  
Drago ◽  
Rapisarda ◽  
...  
Keyword(s):  
Dna Repair ◽  
Occupational Exposure ◽  
Ionizing Radiation ◽  
Linear Regression Analysis ◽  
Detoxification Enzymes ◽  
Low Doses ◽  
Gstt1 Null Genotype ◽  
Genotoxic Damage ◽  
Chromosome Breaks ◽  
Exposed Workers

The study investigated the influence of genetic polymorphisms of the enzymes for DNA repair and detoxification of reactive intermediates on spontaneous and bleomycin-induced (BLM) genotoxic damage in 43 workers exposed to very low doses of ionizing radiation (IR) (mean cumulative dose 5.31 mSv) and 43 subjects with no occupational exposure to IR (controls). In all the subjects examined, the frequency of chromosome aberrations (CAs) and micronuclei (MN), both spontaneous and BLM-induced, the Comet assay parameters (tail intensity), the genotypic variants of the DNA repair enzymes XRCC1 (Arg194Trp, Arg280His, Arg399Gln), XRCC3 (Thr241Met), XPD (Lys751Gln), and of the detoxification enzymes GSTM1 and GSTT1 (null genotype) and BLMH (A1450G) were determined. Among the biomarkers considered, only the frequency of total CAs (p < 0.05), and in particular of chromosome breaks (p < 0.01), was found to be significantly higher in the exposed workers than the controls. The frequency of spontaneous MN was higher in subjects with at least one allelic variant in XRCC1 than in carriers of the wild-type, but again only in exposed workers (p = 0.046). Linear regression analysis showed a positive dependency of the frequency of spontaneous chromosome breaks on occupational exposure, and a dependency of the frequency of BLM-induced MN negative on occupational exposure and positive on alcohol consumption and the null GSTM1 genotype. In conclusion, the frequency of chromosome breaks seems to be a useful cytogenetic biomarker for exposure to very low doses of IR, while only the combined effect of different gene variants or genetic, occupational, and lifestyle habits factors seems to be able to modulate the genotoxic effect of very low doses of IR.

Patients with Systemic Sclerosis Present Increased DNA Damage Differentially Associated with DNA Repair Gene Polymorphisms

2014 ◽  
Vol 41 (3) ◽  
pp. 458-465 ◽  
Author(s):  
Gustavo Martelli Palomino ◽  
Carmen L. Bassi ◽  
Isabela J. Wastowski ◽  
Danilo J. Xavier ◽  
Yara M. Lucisano-Valim ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Systemic Sclerosis ◽  
Blood Cells ◽  
Gene Polymorphisms ◽  
Peripheral Blood Cells ◽  
Dna Repair Genes ◽  
Repair Gene ◽  
Dna Repair Gene ◽  
Repair Genes

Objective.Patients with systemic sclerosis (SSc) exhibit increased toxicity when exposed to genotoxic agents. In our study, we evaluated DNA damage and polymorphic sites in 2 DNA repair genes (XRCC1Arg399Gln andXRCC4Ile401Thr) in patients with SSc.Methods.A total of 177 patients were studied for DNA repair gene polymorphisms. Fifty-six of them were also evaluated for DNA damage in peripheral blood cells using the comet assay.Results.Compared to controls, the patients as a whole or stratified into major clinical variants (limited or diffuse skin involvement), irrespective of the underlying treatment schedule, exhibited increased DNA damage.XRCC1(rs: 25487) andXRCC4(rs: 28360135) allele and genotype frequencies observed in patients with SSc were not significantly different from those observed in controls; however, theXRCC1Arg399Gln allele was associated with increased DNA damage only in healthy controls and theXRCC4Ile401Thr allele was associated with increased DNA damage in both patients and controls. Further, theXRCC1Arg399Gln allele was associated with the presence of antinuclear antibody and anticentromere antibody. No association was observed between these DNA repair gene polymorphic sites and clinical features of patients with SSc.Conclusion.These results corroborate the presence of genomic instability in SSc peripheral blood cells, as evaluated by increased DNA damage, and show that polymorphic sites of theXRCC1andXRCC4DNA repair genes may differentially influence DNA damage and the development of autoantibodies.

scholarly journals Role of DNA Repair by Nonhomologous-End Joining in Bacillus subtilis Spore Resistance to Extreme Dryness, Mono- and Polychromatic UV, and Ionizing Radiation

2007 ◽  
Vol 189 (8) ◽  
pp. 3306-3311 ◽  
Author(s):  
Ralf Moeller ◽  
Erko Stackebrandt ◽  
Günther Reitz ◽  
Thomas Berger ◽  
Petra Rettberg ◽  
...  
Keyword(s):  
Dna Repair ◽  
Bacillus Subtilis ◽  
Ionizing Radiation ◽  
Ultrahigh Vacuum ◽  
Nonhomologous End Joining ◽  
Wild Type ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Spore Resistance

ABSTRACT The role of DNA repair by nonhomologous-end joining (NHEJ) in spore resistance to UV, ionizing radiation, and ultrahigh vacuum was studied in wild-type and DNA repair mutants (recA, splB, ykoU, ykoV, and ykoU ykoV mutants) of Bacillus subtilis. NHEJ-defective spores with mutations in ykoU, ykoV, and ykoU ykoV were significantly more sensitive to UV, ionizing radiation, and ultrahigh vacuum than wild-type spores, indicating that NHEJ provides an important pathway during spore germination for repair of DNA double-strand breaks.

The ionizing radiation-induced replication protein A phosphorylation response differs between ataxia telangiectasia and normal human cells

1993 ◽  
Vol 13 (12) ◽  
pp. 7222-7231
Author(s):  
V F Liu ◽  
D T Weaver
Keyword(s):  
Dna Repair ◽  
Ionizing Radiation ◽  
Gamma Irradiation ◽  
Ataxia Telangiectasia ◽  
Protein A ◽  
Replication Protein A ◽  
Replication Protein ◽  
Inherited Disease ◽  
Dna Replication And Repair ◽  
In Cells

Replication protein A (RPA), the trimeric single-stranded DNA-binding protein complex of eukaryotic cells, is important to DNA replication and repair. Phosphorylation of the p34 subunit of RPA is modulated by the cell cycle, occurring during S and G2 but not during G1. The function of phosphorylated p34 remains unknown. We show that RPA p34 phosphorylation is significantly induced by ionizing radiation. The phosphorylated form, p36, is similar if not identical to the phosphorylated S/G2 form. gamma-Irradiation-induced phosphorylation occurs without new protein synthesis and in cells in G1. Mutation of cdc2-type protein kinase phosphorylation sites in p34 eliminates the ionizing radiation response. The gamma-irradiation-induced phosphorylation of RPA p34 is delayed in cells from ataxia telangiectasia, a human inherited disease conferring DNA repair defects and early-onset tumorigenesis. UV-induced phosphorylation of RPA p34 occurs less rapidly than gamma-irradiation-induced phosphorylation but is kinetically similar between ataxia telangiectasia and normal cells. This is the first time that modification of a repair protein, RPA, has been linked with a DNA damage response and suggests that phosphorylation may play a role in regulating DNA repair pathways.

Genotoxic risk in health-care professionals occupationally exposed to low doses of ionizing radiation

2020 ◽  
Vol 36 (5) ◽  
pp. 356-370 ◽  
Author(s):  
Flávio Manoel Rodrigues da Silva-Júnior ◽  
Ronan Adler Tavella ◽  
Caroline Lopes Feijo Fernandes ◽  
Alexandra Silveira Mortola ◽  
Gianni Goulart Peraza ◽  
...  
Keyword(s):  
Occupational Exposure ◽  
Ionizing Radiation ◽  
Internal Control ◽  
Health Care Professionals ◽  
Skin Color ◽  
Lifestyle Factors ◽  
Exposed Group ◽  
External Control ◽  
X Rays ◽  
Significant Difference

The purpose of this study was to evaluate the potential influence of occupational ionizing radiation (IR) exposure on health professionals, assessing DNA damage using the comet and micronucleus (MN) assays and analyzing relative risks, correlations, and associated factors between outcomes and socioeconomic and lifestyle factors. Blood and buccal samples were collected from 36 workers, who actively participated in an imaging sector of a hospital, who were either exposed to IR directly or indirectly (9 internal control and 27 exposed), and 27 individuals living in the same city but with no occupational exposure (external control, unexposed/healthy). All radiation dosages performed on the 36 workers were less than 20 mSv/y, not exceeding the effective dose limit for occupational exposure. A questionnaire identified socioeconomic and lifestyle factors associated with the outcomes. The results of the MN assay showed a significant difference between both internal control and the exposed group when compared to the external control. For the comet assay, there were significant differences between the percent of tail DNA of the exposed group and external controls, but no difference was found between the exposed group and internal controls. Relative risk associations were found in time of exposure, hours worked per week, and perceived stress. Correlations were found between the outcomes and age, consumption of alcohol, and frequencies of X-rays during life. Variables that showed to be significant in the adjusted analysis were skin color and recent exposure to radiation. Albeit limited, the findings of this study suggest genotoxicity in both blood and buccal mucosa cells of workers exposed directly or indirectly to IR and that lifestyle and socioeconomic factors are associated and correlated with the risk of developing these outcomes.

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