DNA damage in lymphocytes after irradiation with 211At and 188Re

2009 ◽  
Vol 48 (06) ◽  
pp. 221-226 ◽  
Author(s):  
M. Wendisch ◽  
G. Wunderlich ◽  
R. Freudenberg ◽  
J. Kotzerke ◽  
R. Runge
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Mononuclear Cells ◽  
Dna Lesions ◽  
Alpha Particles ◽  
Alkaline Comet Assay ◽  
Peripheral Blood Mononuclear ◽  
Strand Breaks ◽  
Neutral Comet Assay ◽  
Dna Strand

Summary Aim: Ionising radiation produces many types of DNA lesions of different complexity. High linear energy transfer (LET) types of radiation are biological more effective than low LET radiation. In the present work we applied the single cell gel electrophoreses (comet assay) to study the induction of initial DNA damage, efficiency of repair and residual DNA damage in lymphocytes after treatment with 211At and 188Re. Methods: Peripheral blood mononuclear cells (PBMC) were isolated from heparinized blood of healthy donors and irradiated with 211At and 188Re at different doses. The comet assay was performed under alkaline and neutral conditions in order to detect the initial DNA damage and its repair. The measure of damage was % tail DNA (percentage of DNA in the tail). Results: After treatment of cells with 188Re the initial DNA damage (% tail DNA) detected with the alkaline comet assay was higher than the damage measured for 211At. The neutral comet assay estimated higher tail intensities for 211At in contrast to 188Re. Compared with the complete repair (10%) after irradiation with 188Re, the radiotoxicity of alpha particles indicated reduced rejoining of DNA strand breaks (60–80% residual damage). Rejoining of DNA damage measured by the neutral comet method detected about 70% unrepaired strand breaks for 211At and 188Re. Conclusions: There are major differences between the repair of strand breaks caused by 188Re and 211At detected by the alkaline comet assay. The DNA-damage induced by the high LET Emitter 211At remains nearly unrepaired detected by both alkaline and neutral comet assay. Represented data following irradiation of lymphocytes with alpha and beta particles demonstrated higher biological effectiveness of 211At by factors of 2.0–2.5.

scholarly journals Characterization of Escherichia coli DNA Lesions Generated within J774 Macrophages

2000 ◽  
Vol 182 (18) ◽  
pp. 5225-5230 ◽  
Author(s):  
Eliana Schlosser-Silverman ◽  
Maya Elgrably-Weiss ◽  
Ilan Rosenshine ◽  
Ron Kohen ◽  
Shoshy Altuvia
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Respiratory Burst ◽  
Defense Mechanism ◽  
Dna Lesions ◽  
Intracellular Bacteria ◽  
Bacterial Killing ◽  
Strand Breaks ◽  
E Coli ◽  
Dna Strand

ABSTRACT Macrophages are armed with multiple oxygen-dependent and -independent bactericidal properties. However, the respiratory burst, generating reactive oxygen species, is believed to be a major cause of bacterial killing. We exploited the susceptibility of Escherichia coli in macrophages to characterize the effects of the respiratory burst on intracellular bacteria. We show that E. coli strains recovered from J774 macrophages exhibit high rates of mutations. We report that the DNA damage generated inside macrophages includes DNA strand breaks and the modification 8-oxo-2′-deoxyguanosine, which are typical oxidative lesions. Interestingly, we found that under these conditions, early in the infection the majority of E. coli cells are viable but gene expression is inhibited. Our findings demonstrate that macrophages can cause severe DNA damage to intracellular bacteria. Our results also suggest that protection against the macrophage-induced DNA damage is an important component of the bacterial defense mechanism within macrophages.

scholarly journals The role of Sp1 in the detection and elimination of cells with persistent DNA strand breaks

NAR Cancer ◽  
2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Polina S Loshchenova ◽  
Svetlana V Sergeeva ◽  
Sally C Fletcher ◽  
Grigory L Dianov
Keyword(s):  
Dna Damage ◽  
Cancer Therapy ◽  
Genome Stability ◽  
Dna Strand Breaks ◽  
Dna Lesions ◽  
Exogenous Dna ◽  
Strand Breaks ◽  
Specificity Factor ◽  
Dna Strand

Abstract Maintenance of genome stability suppresses cancer and other human diseases and is critical for organism survival. Inevitably, during a life span, multiple DNA lesions can arise due to the inherent instability of DNA molecules or due to endogenous or exogenous DNA damaging factors. To avoid malignant transformation of cells with damaged DNA, multiple mechanisms have evolved to repair DNA or to detect and eradicate cells accumulating unrepaired DNA damage. In this review, we discuss recent findings on the role of Sp1 (specificity factor 1) in the detection and elimination of cells accumulating persistent DNA strand breaks. We also discuss how this mechanism may contribute to the maintenance of physiological populations of healthy cells in an organism, thus preventing cancer formation, and the possible application of these findings in cancer therapy.

scholarly journals The Radioprotective Effect of Procaine and Procaine-Derived Product Gerovital H3 in Lymphocytes from Young and Aged Individuals

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Anca Ungurianu ◽  
Denisa Margina ◽  
Claudia Borsa ◽  
Cristina Ionescu ◽  
Gudrun von Scheven ◽  
...  
Keyword(s):  
Mononuclear Cells ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Chemical Compounds ◽  
Dna Strand Breaks ◽  
Peripheral Blood Mononuclear ◽  
Strand Breaks ◽  
Young Subjects ◽  
Living Organisms ◽  
Dna Strand

Ionizing radiation induces genomic instability in living organisms, and several studies reported an ageing-dependent radiosensitivity. Chemical compounds, such as scavengers, radioprotectors, and modifiers, contribute to reducing the radiation-associated toxicity. These compounds are often antioxidants, and therefore, in order to be effective, they must be present before or during exposure to radiation. However, not all antioxidants provide radioprotection. In this study, we investigated the effects of procaine and of a procaine-based product Gerovital H3 (GH3) on the formation of endogenous and X-ray-induced DNA strand breaks in peripheral blood mononuclear cells (PBMCs) isolated from young and elderly individuals. Interestingly, GH3 showed the strongest radioprotective effects in PBMCs from young subjects, while procaine reduced the endogenous amount of DNA strand breaks more pronounced in aged individuals. Both procaine and GH3 inhibited lipid peroxidation, but procaine was more effective in inhibiting mitochondria free radicals’ generation, while GH3 showed a higher antioxidant action on macrophage-induced low-density lipoprotein oxidation. Our findings provide new insights into the mechanisms underlying the distinct effects of procaine and GH3 on DNA damage.

Detection of DNA strand breaks by comet assay in sputum leucocytes of bitumen-exposed workers: A pilot study

2010 ◽  
Vol 29 (9) ◽  
pp. 721-729 ◽  
Author(s):  
B. Marczynski ◽  
M. Raulf-Heimsoth ◽  
B. Pesch ◽  
B. Kendzia ◽  
HU Käfferlein ◽  
...  
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Rank Correlation ◽  
Dna Strand Breaks ◽  
Strand Breaks ◽  
Blood Lymphocytes ◽  
Exposed Workers ◽  
Before And After ◽  
Dna Strand ◽  
Post Shift

DNA strand breaks were determined in leucocytes of induced sputum (IS) and compared with DNA strand breaks in blood lymphocytes from 42 bitumen-exposed workers pre and post shift. Comet assay results were expressed in arbitrary units based on visual scoring (sputum leucocytes) and Olive tail moment (OTM, blood lymphocytes). DNA damage in IS leucocytes was overall high but did not change during shift. Level of DNA strand breaks in IS samples correlated with total cell count and neutrophil content (Spearman rank correlation coefficient rs = 0.47, p = 0.001, rs= 0.48, p = 0.001, respectively) and with IL-8 concentration before and after shift (rs = 0.31, P = 0.048, and rs = 0.43, P = 0.005). DNA damage in IS was not associated with DNA strand breaks in blood lymphocytes (rs = —0.04, p = 0.802 before shift, rs = 0.27, p = 0.088 after shift). A higher level of DNA strand breaks was measured in blood lymphocytes before shift (median OTM 1.7 before and 1.3 after shift, p = 0.023). A strong correlation was found between the number of neutrophils and IL-8 concentration in IS before and after shift (rs = 0.77 and rs= 0.75, p < 0.001). This study showed an association between genotoxic and inflammatory effects in the lower airways and compared simultaneously DNA strand breaks in IS and blood of bitumen-exposed workers.

Imatinib (STI571) Induces DNA Damage in BCR/ABL-Expressing Leukemic Cells but Not in Normal Lymphocytes.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4353-4353
Author(s):  
Janusz Blasiak ◽  
Jozef Drzewoski ◽  
Tomasz Poplawski ◽  
Agnieszka Czechowska
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Human Lymphocytes ◽  
Direct Interaction ◽  
K562 Cells ◽  
Dna Lesions ◽  
Dna Glycosylase ◽  
Leukemic Cells ◽  
Drug Induced ◽  
Strand Breaks

Abstract Imatinib (STI571) is a 2-phenylaminopyrimidine derivative used mostly in the treatment of chronic myeloid leukaemia. It targets specifically the BCR/ABL oncogenic tyrosine kinase, inhibiting its activity. Using the alkaline comet assay we showed that STI571 at concentrations ranging from 0.05 to 2 μM induced DNA damage in human leukemic K562 cells expressing the BCR/ABL oncogene, whereas it had no effect in normal human lymphocytes. Because the extent of DNA damage observed in the neutral and pH 12.1 versions of the comet assay was much lesser than in the alkaline version, we concluded that the drug induced DNA alkali-labile sites rather than strand breaks. Imatinib did not induce DNA strand breaks in the direct interaction with DNA as examined by the plasmid relaxation assay. K562 cells were unable to repair H2O2-induced DNA damage during a 120-min incubation, if they had been preincubated with STI571, whereas normal lymphocytes did so within 60 min. Pre-treatment of K562 cells with vitamins A, C and E reduced the extent of DNA damage evoked by STI571. Similar results brought experiments with the nitrone spin traps POBN and PBN, suggesting that free radicals may be involved in the formation of DNA lesions induced by STI571 in K562 cells. These cells exposed to imatinib and treated with endonuclease III, formamidopyrimidine-DNA glycosylase and 3-methyladenine-DNA glycosylase II, the enzymes recognizing oxidized and alkylated bases, displayed greater extent of DNA damage than those not treated with these enzymes.

Use of comet assay for the risk assessment of oil- and chemical-industry workers

2014 ◽  
Vol 155 (47) ◽  
pp. 1872-1875 ◽  
Author(s):  
János Megyesi ◽  
Anna Biró ◽  
László Wigmond ◽  
Jenő Major ◽  
Anna Tompa
Keyword(s):  
Dna Damage ◽  
Occupational Exposure ◽  
Comet Assay ◽  
Oxidative Dna Damage ◽  
Microscopic Method ◽  
Monitoring Method ◽  
Strand Breaks ◽  
Cell Counts ◽  
Polycyclic Aromatic ◽  
Dna Strand

Introduction: The comet assay is a fluorescent microscopic method that is able to detect DNA strand-breaks even in non-proliferative cells in samples with low cell counts. Aim: The aim of the authors was to measure genotoxic DNA damage and assess oxidative DNA damage caused by occupational exposure in groups exposed to benzene, polycyclic aromatic carbohydrates and styrene at the workplace in order to clarify whether the comet assay can be used as an effect marker tool in genotoxicology monitoring. Method: In addition to the basic steps of the comet assay, one sample was treated with formamido-pirimidine-DNA-glycolase restriction-enzyme that measures oxidative DNA damage. Results: An increase was observed in tail moments in each group of untreated and Fpg-treated samples compared to the control. Conclusions: It can be concluded that occupational exposure can be detected with the method. The comet assay may prove to be an excellent effect marker and a supplementary technique for monitoring the presence or absence of genotoxic effects. Orv. Hetil., 2014, 155(47), 1872–1875.

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