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Vivek Kumar PR, Karuppasamy CV, Ramachandran EN, Anil Kumar V, Jaikrishan G, Das B. Premature chromosome condensation assay to study influence of high-level natural radiation on the initial DNA double strand break repair in human G 0 lymphocytes. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2020; 849:503141. [PMID: 32087855 DOI: 10.1016/j.mrgentox.2020.503141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/10/2020] [Accepted: 01/14/2020] [Indexed: 12/26/2022]
Abstract
The inherent capacity of individuals to efficiently repair ionizing radiation induced DNA double strand breaks (DSBs) may be inherited, however, it is influenced by several epigenetic and environmental factors. A pilot study tested whether chronic low dose natural radiation exposure influences the rejoining of initial DNA DSBs induced by a 2 Gy γ-irradiation in 22 individuals from high (>1.5 mGy/year) and normal (≤1.5 mGy/year) level natural radiation areas (H&NLNRA) of Kerala. Rejoining of DSBs (during 1 h at 37 °C, immediately after irradiation) was evaluated at the chromosome level in the presence and absence of wortmannin (a potent inhibitor of DSB repair in normal human cells) using a cell fusion-induced premature chromosome condensation (PCC) assay. The PCC assay quantitates DSBs in the form of excess chromosome fragments in human G0 lymphocytes without the requirement for cell division. A quantitative difference was observed in the early rejoining of DNA DSBs between individuals from HLNRA and NLNRA, with HLNRA individuals showing a higher (P = 0.05) mean initial repair ratio. The results indicate an influence of chronic low dose natural radiation on initial DNA DSB repair in inhabitants of HLNRA of the Kerala coast.
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Affiliation(s)
- P R Vivek Kumar
- Low Level Radiation Research Laboratory, Low Level Radiation Research Section (LLRRS), Radiation Biology & Health Sciences Division (RB&HSD), Bio-Science Group, Bhabha Atomic Research Centre (BARC), Beach Road, Kollam, 691 001, Kerala, India.
| | - C V Karuppasamy
- Low Level Radiation Research Laboratory, Low Level Radiation Research Section (LLRRS), Radiation Biology & Health Sciences Division (RB&HSD), Bio-Science Group, Bhabha Atomic Research Centre (BARC), Beach Road, Kollam, 691 001, Kerala, India
| | - E N Ramachandran
- Low Level Radiation Research Laboratory, Low Level Radiation Research Section (LLRRS), Radiation Biology & Health Sciences Division (RB&HSD), Bio-Science Group, Bhabha Atomic Research Centre (BARC), Beach Road, Kollam, 691 001, Kerala, India
| | - V Anil Kumar
- Low Level Radiation Research Laboratory, Low Level Radiation Research Section (LLRRS), Radiation Biology & Health Sciences Division (RB&HSD), Bio-Science Group, Bhabha Atomic Research Centre (BARC), Beach Road, Kollam, 691 001, Kerala, India
| | - G Jaikrishan
- Low Level Radiation Research Laboratory, Low Level Radiation Research Section (LLRRS), Radiation Biology & Health Sciences Division (RB&HSD), Bio-Science Group, Bhabha Atomic Research Centre (BARC), Beach Road, Kollam, 691 001, Kerala, India
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Kazimirova A, Baranokova M, Staruchova M, Drlickova M, Volkovova K, Dusinska M. Titanium dioxide nanoparticles tested for genotoxicity with the comet and micronucleus assays in vitro, ex vivo and in vivo. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 843:57-65. [PMID: 31421740 DOI: 10.1016/j.mrgentox.2019.05.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/24/2019] [Accepted: 05/01/2019] [Indexed: 11/28/2022]
Abstract
The genotoxicity of TiO2 nanoparticles (NPs) was assessed with the cytokinesis-block micronucleus (CBMN) assay in TK6 lymphoblastoid cells, lymphocytes from human volunteers, and bone marrow erythrocytes from rats exposed in vivo; and with the comet assay (detecting both strand breaks and oxidised purines) in human and rat peripheral blood mononuclear cells (PBMCs). NPs were dispersed using three different methods giving different size distribution and stability. On average, TiO2 NPs caused no increase in micronuclei in TK6 cells, rat bone marrow erythrocytes or human lymphocytes (though lymphocytes from 3 out of 13 human subjects showed significant increases). PBMCs from rats treated in vivo with a single dose of NPs dispersed by a method with low agglomeration showed an increase in strand breaks after 1 day. TiO2 NPs dispersed in a stable, non-agglomerated state induced DNA strand breaks at 75 μg/cm2 after 4 h exposure of human PBMCs and at 15 μg/cm2 and 75 μg/cm2 after 24 h exposure, but no increase in DNA oxidation was seen. Overall, NPs in an agglomerated state did not cause DNA damage. However, at the individual level, significant increases in strand breaks were seen in PBMCs from most of the volunteers. Cells from one volunteer showed positive effects in all conditions and both tests, while cells from another volunteer appeared to be completely resitant to TiO2 NPs. The implication is that some individuals may be more sensitive than others to effects of this nanomaterial. Differences seen in results obtained with the micronucleus and the comet assay may be due to the mechanisms underlying the genotoxic effects of TiO2 NPs and the different endpoints represented by the two assays.
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Affiliation(s)
- Alena Kazimirova
- Department of Biology, Faculty of Medicine, Slovak Medical University, Limbova 12, 833 03, Bratislava, Slovakia.
| | - Magdalena Baranokova
- Department of Biology, Faculty of Medicine, Slovak Medical University, Limbova 12, 833 03, Bratislava, Slovakia
| | - Marta Staruchova
- Department of Biology, Faculty of Medicine, Slovak Medical University, Limbova 12, 833 03, Bratislava, Slovakia
| | - Martina Drlickova
- Department of Biology, Faculty of Medicine, Slovak Medical University, Limbova 12, 833 03, Bratislava, Slovakia
| | - Katarina Volkovova
- Department of Biology, Faculty of Medicine, Slovak Medical University, Limbova 12, 833 03, Bratislava, Slovakia
| | - Maria Dusinska
- NILU-Norwegian Institute for Air Research, Kjeller, Norway
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Salgaonkar NA, Thakare PM, Junnarkar MV, Kapadnis BP, Mandal A, Eriksson C, Nawani NN. Use of N,N’-diacetylchitobiose in decreasing toxic effects of indoor air pollution by preventing oxidative DNA damage. Biologia (Bratisl) 2016. [DOI: 10.1515/biolog-2016-0075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Kumar PRV, Seshadri M, Jaikrishan G, Das B. Effect of chronic low dose natural radiation in human peripheral blood mononuclear cells: Evaluation of DNA damage and repair using the alkaline comet assay. Mutat Res 2015; 775:59-65. [PMID: 25879710 DOI: 10.1016/j.mrfmmm.2015.03.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 03/15/2015] [Accepted: 03/22/2015] [Indexed: 06/04/2023]
Abstract
This study investigates whether peripheral blood mononuclear cells (PBMCs) from inhabitants of Kerala in southwest India, exposed to chronic low dose natural radiation in vivo (>1 mSv year(-1)), respond with a radioadaptive response to a challenging dose of gamma radiation. Toward this goal, PBMCs isolated from 77 subjects from high-level natural radiation areas (HLNRA) and 37 subjects from a nearby normal level natural radiation area (NLNRA) were challenged with 2 Gy and 4 Gy gamma radiation. Subjects from HLNRA were classified based on the mean annual effective dose received, into low dose group (LDG) and high dose group (HDG) with mean annual effective doses of 2.69 mSv (N=43, range 1.07 mSv year(-1) to 5.55 mSv year(-1)) and 9.62 mSv (N = 34, range 6.07 mSv year(-1) to 17.41 mSv year(-1)), respectively. DNA strand breaks and repair kinetics (at 7 min, 15 min and 30 min after 4 Gy) were evaluated using the alkaline single cell gel electrophoresis (comet) assay. Initial levels of DNA strand breaks observed after either a 2 Gy or a 4 Gy challenging dose were significantly lower in subjects of the HDG from HLNRA compared to subjects of NLNRA (2 Gy, P = 0.01; 4 Gy, P = 0.02) and LDG (2 Gy P = 0.01; 4 Gy, P=0.05). Subjects of HDG from HLNRA showed enhanced rejoining of DNA strand breaks (HDG/NLNRA, P = 0.06) during the early stage of repair (within 7 min). However at later times a similar rate of rejoining of strand breaks was observed across the groups (HDG, LDG and NLNRA). Preliminary results from our study suggest in vivo chronic low-level natural radiation provides an initial exposure that allows an adaptation to a subsequent higher radiation exposure, perhaps through improving DNA repair via an unknown mechanism. Therefore, further investigations would be necessary in this population to understand the biological and health effects of chronic low-level natural radiation exposures.
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Affiliation(s)
- P R Vivek Kumar
- Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala, India.
| | - M Seshadri
- Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - G Jaikrishan
- Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala, India
| | - Birajalaxmi Das
- Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
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Ding G, Liu F, Feng C, Xu J, Ding Q. [Association between the myeloperoxidase gene polymorphisms and the susceptibility to prostate cancer: a case-control study in a Chinese population]. Actas Urol Esp 2013; 37:79-82. [PMID: 23260186 DOI: 10.1016/j.acuro.2012.03.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 03/10/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND AND OBJECTIVES Prostate cancer (PCa) is the most common cancer among men in most western populations. The polymorphisms of the myeloperoxidase (MPO) gene have been correlated with abnormal MPO expression and increased risk of various types of cancers. Our study aimed to evaluate the association between the genetic polymorphisms and the risk of prostate cancer. METHODS Genotyping was carried out by using the genotyping system (MassARRAY iPLEX; Sequenom, Inc., San Diego, CA, USA) on 1,108 PCa patients and 1,525 cancer-free controls in a Chinese Han population. RESULTS Although one SNP (rs8082134, P < 0.050) was significant, it is very rare and unstable. Other SNPs had no significant difference between genotype distributions in the PCa patients and the control group. Totally, SNPs in the MPO gene is not associated with PCa risk. CONCLUSION Our data showed a limited association between the MPO SNPs and the susceptibility to PCa in population of Chinese Han population. The possible association of rs8082134 of MPO with PCa risk need further clarification.
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Lu Y, Takeshita T, Morimoto K. Single-cell gel electrophoresis (SCG)-A review and discussion. Environ Health Prev Med 2012; 2:53-8. [PMID: 21432452 DOI: 10.1007/bf02931964] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/1997] [Accepted: 03/06/1997] [Indexed: 11/28/2022] Open
Abstract
Single-cell gel electrophoresis (SCG) is a simple, sensitive and effective technique. Being able to reflect quantitatively the genotoxicity of many hazardous agents, it is promising for application in environmental genotoxic monitoring and the study of carcinogenesis. In clinics, it can be used to evaluate the DNA repair ability and monitor DNA breaks during cancer therapy. As a biomarker, it has its own merits and limitations, being different from other biomarkers such as sister chromatid exchange (SCE) test and micronuclei (MN) assay. In many studies, it is more sensitive than SCE or MN. Combination studies with other biomarkers like SCE, MN, chromosomal aberration, bcl-2 and genetic polymorphisms have begun to demonstrate its great importance for the understanding of carcinogenesis and the genotoxicities of environmental factors.
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Affiliation(s)
- Y Lu
- Department of Hygiene and Preventive Medicine, Osaka University School of Medicine, 2-2 Yamadaoka, Suita, 565, Osaka, Japan
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Ballal NV, Rao BN, Mala K, Bhat KS, Rao BSS. Assessment of genotoxic effect of maleic acid and EDTA: a comparative in vitro experimental study. Clin Oral Investig 2012; 17:1319-27. [DOI: 10.1007/s00784-012-0818-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Accepted: 08/01/2012] [Indexed: 11/29/2022]
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Møller P, Friis G, Christensen PH, Risom L, Plesner G, Kjaersgaard J, Vinzents P, Loft S, Jensen A, Tved M. Intra-laboratory Comet Assay Sample Scoring Exercise for Determination of Formamidopyrimidine DNA Glycosylase Sites in Human Mononuclear Blood Cell DNA. Free Radic Res 2009; 38:1207-14. [PMID: 15621698 DOI: 10.1080/10715760400016824] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Oxidative DNA damage detected by the comet assay as formamidopyrimidine DNA glycosylase (FPG) sensitive sites, almost as a rule is reported as comet assay score rather than numerical sites in the genome, probably because the latter requires X-ray calibration. We compared the ability of five experienced and five inexperienced comet assay investigators to detect a dose-response relationship in irradiated A549 lung epithelial cell culture samples (0, 10 Gy and three samples of 5 Gy), based on an arbitrary five class scoring system. The samples were scored on three different occasions, thus allowing determination of the variation in sample scoring. All investigators qualitatively distinguished between samples in a dose-dependent manner, albeit with large variation in the slope and intercept of dose-response curves. There was a tendency that investigators with experience in scoring A549 cells had more consistent results than experienced investigators who had only scored lymphocytes or inexperienced investigators. The inexperienced investigators improved their scoring ability during the three sessions. Subsequently we showed that the variation in baseline level of FPG modifications in mononuclear blood cells of five healthy humans was lower when investigators used their individual X-ray calibration curve as compared to a common calibration curve. In conclusion, this study showed that comet assay investigators score differently when using a five class scoring system, which indicates that more consistent estimations of FPG sites in the genome are obtained by use of investigators' individual X-ray calibrations.
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Affiliation(s)
- Peter Møller
- Institute of Public Health (c/o Department of Pharmacology), The Panum Institute of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen N, Denmark.
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Soltani F, Mosaffa F, Iranshahi M, Karimi G, Malekaneh M, Haghighi F, Behravan J. Evaluation of antigenotoxicity effects of umbelliprenin on human peripheral lymphocytes exposed to oxidative stress. Cell Biol Toxicol 2008; 25:291-6. [DOI: 10.1007/s10565-008-9083-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2008] [Accepted: 04/18/2008] [Indexed: 11/29/2022]
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Braz MG, Marcondes JPDC, Matsumoto MA, Duarte MAH, Salvadori DMF, Ribeiro DA. Genotoxicity in primary human peripheral lymphocytes after exposure to radiopacifiers in vitro. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2008; 19:601-5. [PMID: 17619988 DOI: 10.1007/s10856-007-3000-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2006] [Accepted: 02/22/2007] [Indexed: 05/16/2023]
Abstract
Taking into consideration that DNA damage plays an important role in carcinogenesis, the purpose of this study was to evaluate whether some radiopacifiers widely used in clinical practice are able to induce genetic damage in primary human cells in vitro. Human peripheral lymphocytes obtained from 10 healthy volunteers were exposed to barium sulphate (BaSO(4)), zirconium oxide (ZnO(2)) and bismuth oxide (Bi(2)O(3)) at final concentrations ranging from 1 to 1000 microg/mL for 1 h at 37 degrees C. The negative control group was treated with vehicle control (phosphate buffer solution) for 1 h at 37 degrees C and the positive control group was treated with hydrogen peroxide (at 100 microM) for 5 min on ice. Results were analyzed by the Friedman non-parametric test. The results pointed all compounds tested out did not induce DNA breakage in human peripheral lymphocytes as depicted by the mean tail moment and tail intensity in all concentrations tested. In summary, our results indicate that exposure to these radiopacifiers may not be a factor that increases the level of DNA lesions in human peripheral lymphocytes as detected by single cell gel (comet) assay.
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Affiliation(s)
- Mariana Gobbo Braz
- Department of Pathology, Botucatu Medical School, São Paulo State University, Botucatu, SP, Brazil
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11
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Weng H, Lu Y, Weng Z, Morimoto K. Differential DNA damage induced by H2O2 and bleomycin in subpopulations of human white blood cells. Mutat Res 2007; 652:46-53. [PMID: 18262831 DOI: 10.1016/j.mrgentox.2007.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 11/23/2007] [Accepted: 12/08/2007] [Indexed: 11/24/2022]
Abstract
The purpose of this study was to characterize the differential sensitivities of various subpopulations of human white blood cells after exposure to H2O2 (an oxidant agent) and bleomycin (a radiomimetic glycopeptide), in vitro, using single-cell gel electrophoresis (SCGE). Human peripheral blood was fractionated into mononuclear cells, which were further separated into monocytes, CD4+ T-cells, CD8+ T-cells, B-cells and natural killer cells (NK cells). The separated fractions were exposed to different doses of H2O2 and bleomycin, and then used to measure levels of induced and basal DNA damage. There was a significant increase in the amount of DNA damage in CD4+ T-cells, CD8+ T-cells, NK cells and B-cells when treated with H2O2 and bleomycin, whereas monocytes had the lowest sensitivity to H2O2 compared with the other cell fractions, but no lower sensitivity to bleomycin. Furthermore, CD4+ T-cells and CD8+ T-cells had the highest levels of basal DNA damage. When basal DNA damage was taken into account, NK cells tended to show a higher sensitivity to H2O2 than CD4+ T-cells, CD8+ T-cells and monocytes. In addition, B-cells, which showed lower sensitivity to H2O2 than CD4+ T-cells, CD8+ T-cells and NK cells when exposed to lower doses of H2O2 (<10 microM), showed higher sensitivity to H2O2 at higher doses (>20 microM). On the other hand, B-cells showed the highest sensitivity to bleomycin.
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Affiliation(s)
- Huachun Weng
- Department of Social and Environmental Medicine, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Osaka 565-0871, Japan
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12
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Kontogianni K, Messini-Nikolaki N, Christou K, Gourgoulianis K, Tsilimigaki S, Piperakis SM. DNA damage and repair capacity in lymphocytes from obstructive sleep apnea patients. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2007; 48:722-727. [PMID: 17973309 DOI: 10.1002/em.20351] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Obstructive sleep apnea (OSA) syndrome is a respiratory disease that is linked to heart attacks and high blood pressure. In the present study, we used the Comet assay to compare basal DNA damage and DNA damage induction by hydrogen peroxide, ethanol, and gamma-irradiation in lymphocytes from 35 OSA patients and 35 controls. We also measured the apoptosis and necrosis produced by these agents and the ability of the lymphocytes to repair the induced DNA damage. It was found that lymphocytes isolated from OSA patients had higher basal levels of DNA damage and were more sensitive to the effects of the DNA-damaging agents than lymphocytes from controls. OSA patients also had a reduced capacity to repair the DNA damage induced by the three agents, but apoptosis and necrosis were similar in OSA patients and the controls.
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Affiliation(s)
- Konstantina Kontogianni
- Faculty of Human Sciences, Department of Pre-School Education, Biology Unit, University of Thessaly, Volos, Greece
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Sjakste NI, Sjakste TG. Possible involvement of DNA breaks in epigenetic regulation of cell differentiation. RUSS J GENET+ 2007. [DOI: 10.1134/s1022795407050018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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da Silva GN, Braz MG, de Camargo EA, Salvadori DMF, Ribeiro DA. Genotoxicity in primary human peripheral lymphocytes after exposure to regular and white mineral trioxide aggregate. ACTA ACUST UNITED AC 2006; 102:e50-4. [PMID: 17052626 DOI: 10.1016/j.tripleo.2006.02.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2006] [Revised: 02/25/2006] [Accepted: 02/27/2006] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Taking into consideration that DNA damage plays an important role in carcinogenesis, the purpose of this study was to evaluate whether regular and white mineral trioxide aggregate (MTA) are able to induce genetic damage in primary human cells. STUDY DESIGN Human peripheral lymphocytes obtained from 10 healthy volunteers were exposed to 2 presentation forms of MTA at final concentrations ranging from 1 to 1000 microg/mL for 1 hour at 37 degrees C. The negative control group was treated with vehicle control (phosphate buffer solution, PBS) for 1 hour at 37 degrees C and the positive control group was treated with hydrogen peroxide (at 100 microM) for 5 minutes on ice. Results were analyzed by the Friedman nonparametric test. RESULTS The results pointed out that either regular or white MTA in all concentrations tested did not induce DNA breakage in human peripheral lymphocytes as depicted by the mean tail moment. CONCLUSION In summary, our results indicate that exposure to MTA may not be a factor that increases the level of DNA lesions in human peripheral lymphocytes as detected by single cell gel (comet) assay.
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Affiliation(s)
- Glenda N da Silva
- Research program, Department of Pathology, São Paulo State University, Sao Paulo, Brazil
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15
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Braz MG, Camargo EA, Salvadori DMF, Marques MEA, Ribeiro DA. Evaluation of genetic damage in human peripheral lymphocytes exposed to mineral trioxide aggregate and Portland cements. J Oral Rehabil 2006; 33:234-9. [PMID: 16512891 DOI: 10.1111/j.1365-2842.2005.01559.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
summary Mineral trioxide aggregate (MTA) and Portland cement are being used in dentistry as root-end-filling material for periapical surgery and for the sealing of communications between the root canal system and the surrounding tissues. However, genotoxicity tests for complete risk assessment of these compounds have not been conducted up to now. In the present study, the genotoxic effects of MTA and Portland cements were evaluated in peripheral lymphocytes from 10 volunteers by the alkaline single cell gel (comet) assay. The results pointed out that the single cell gel (comet) assay failed to detect the presence of DNA damage after a treatment of peripheral lymphocytes by MTA and Portland cements for concentrations up to 1000 mug mL(-1). In summary, our results indicate that exposure to MTA or Portland cements may not be a factor that increases the level of DNA lesions in human peripheral lymphocytes as detected by single cell gel (comet) assay.
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Affiliation(s)
- M G Braz
- Departamento de Patologia, Núcleo de Avaliação Toxicogenética e Cancerígena, TOXICAN, Faculdade de Medicina de Botucatu, UNESP, SP, Brazil
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16
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Andrighetti-Fröhner CR, Kratz JM, Antonio RV, Creczynski-Pasa TB, Barardi CRM, Simões CMO. In vitro testing for genotoxicity of violacein assessed by Comet and Micronucleus assays. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2006; 603:97-103. [PMID: 16359912 DOI: 10.1016/j.mrgentox.2005.11.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 10/24/2005] [Accepted: 11/09/2005] [Indexed: 11/16/2022]
Abstract
Chromobacterium violaceum is a Gram (-) bacteria found in water samples and soils from tropical and subtropical regions of the world. Violacein, the major pigment produced by these bacteria, has been shown to have antibiotic, antitumoral and trypanocidal activities. In the present work, the genotoxicity of violacein was investigated in four different cell lines by using the alkaline Comet assay and in VERO cells using the Micronucleus test. In the alkaline Comet assay, violacein, when tested at concentrations ranging from 0.19 to 1.5 microM, did not induce a significant increase in DNA damage in HEp-2 and MA104 cells. However, violacein was positive for DNA damage in FRhK-4 cells and for both DNA damage and micronuclei in VERO cells, in a concentration-response relationship. The results of this study indicated that violacein is genotoxic in VERO and FRhK-4 cells. These findings contribute to a comprehensive evaluation of the pharmacological potential of violacein.
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Affiliation(s)
- Carla R Andrighetti-Fröhner
- Laboratory of Applied Virology, Department of Pharmaceutical Sciences, Universidade Federal de Santa Catarina, UFSC, Campus Universitário Trindade, Florianópolis, SC, Brazil
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Ladeira MSP, Rodrigues MAM, Freire-Maia DV, Salvadori DMF. Use of Comet assay to assess DNA damage in patients infected by Helicobacter pylori: comparisons between visual and image analyses. Mutat Res 2005; 586:76-86. [PMID: 16084756 DOI: 10.1016/j.mrgentox.2005.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2005] [Revised: 06/04/2005] [Accepted: 06/17/2005] [Indexed: 11/17/2022]
Abstract
Studies of DNA damage in gastric epithelial cells of Helicobacter pylori (H. pylori)-infected patients are conflicting, possibly due to different methods used for scoring DNA damage by Comet assay. Therefore, we compared the sensitivity of visual microscopic analysis (arbitrary units-scores and comets%) and image analysis system (tail moment), in the gastric epithelial cells from the antrum and corpus of 122 H. pylori-infected and 32 non-infected patients. The feasibility of cryopreserved peripheral blood lymphocytes and whole-blood cells for DNA damage biomonitoring was also investigated. In the antrum, the levels of DNA damage were significantly higher in H. pylori-infected patients with gastritis than in non-infected patients with normal mucosa, when evaluated by image analysis system, arbitrary units and comets%. In the corpus, the comets% was not sufficiently sensitive to detect the difference between H. pylori-infected patients with gastritis and non-infected patients with normal mucosa. The image analysis system was sensitive enough to detect differences between non-infected patients and H. pylori-infected patients with mild gastritis and between infected patients with moderate and severe gastritis, in both antrum and corpus, while arbitrary units and comets% were unable to detect these differences. In cryopreserved peripheral blood lymphocytes, the levels of DNA damage (tail moment) were significantly higher in H. pylori-infected patients with moderate and severe gastritis than in non-infected patients. Overall, our results indicate that the image analysis system is more sensitive and adequate to measure the levels of DNA damage in gastric epithelial cells than the other methods assayed.
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Affiliation(s)
- Marcelo S P Ladeira
- Department of Genetics, Bioscience Institute, UNESP, São Paulo State University, Botucatu, São Paulo, Brazil.
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Díaz-Llera S, González-Hernández Y, Prieto-González EA, Azoy A. Genotoxic effect of ozone in human peripheral blood leukocytes. Mutat Res 2002; 517:13-20. [PMID: 12034304 DOI: 10.1016/s1383-5718(02)00022-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The genotoxic effect of ozone was studied in human leukocytes in vitro, using the single cell gel electrophoresis (SCGE) assay. Cell treatment for 1 h at 37 degrees C with 0.9-5.3 mM O(3) resulted in a dose-dependent increase of DNA damage, comparable to that induced by 4-40 mM of H(2)O(2), used as a positive control. This effect of ozone was reversed by post-treatment incubation of the cells for 45-90 min at 37 degrees C, and prevented by pre-incubation of the cells with catalase (20 microg/ml). These results demonstrate that O(3) induces DNA-damage in primary human leukocytes. The damage is rapidly repaired, and probably mediated by the formation of H(2)O(2).
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Affiliation(s)
- Silvia Díaz-Llera
- Centro de Investigaciones y Evaluaciones Biológicas, Instituto de Farmacia y Alimentos, Universidad de La Habana, Apdo. 14024, C.P. 11400, Havana, Cuba.
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19
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Morillas MJ, Guillamet E, Surrallés J, Creus A, Marcos R. Spontaneous and induced genetic damage in T lymphocyte subsets evaluated by the Comet assay. Mutat Res 2002; 514:39-48. [PMID: 11815243 DOI: 10.1016/s1383-5718(01)00319-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
High inter- and intra-individual variability was reported in the level of DNA damage, both spontaneous and induced, when peripheral blood mononuclear leukocytes were used to perform the Comet assay. In order to find out the underlying causes for such variability, different subsets of T lymphocytes were isolated by immunomagnetic cell sorting. The level of DNA damage was evaluated with the alkaline version of the Comet assay by using three different parameters: tail moment, tail length and amount of DNA in the tail (%). Helper T cells (CD4+), cytotoxic T cells (CD8+), their negative fraction and the mixed cell population were evaluated both in untreated cells and after 10 and 20 microM H(2)O(2) treatments. Differences between cell subsets were only observed after H(2)O(2) treatment. The results indicate that, although CD4+ is the fraction with the highest induced level of genetic damage, this value is not high enough to explain the large inter- and intra-individual variability found.
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Affiliation(s)
- M J Morillas
- Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Edifici Cn, Universitat Autònoma de Barcelona, Campus de Bellaterra, 08193, Cerdanyola del Vallès, Spain
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20
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González C, Nájera O, Cortés E, Toledo G, López L, Betancourt M, Ortiz R. Hydrogen peroxide-induced DNA damage and DNA repair in lymphocytes from malnourished children. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2002; 39:33-42. [PMID: 11813294 DOI: 10.1002/em.10038] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The aim of this study was to assess DNA repair capacity in lymphocytes of children with protein calorie malnutrition using the single-cell gel electrophoresis (comet) assay. Repair capacity was assessed by estimating the relative decrease of DNA migration length 5, 15, 30, and 60 min after hydrogen peroxide treatment, in three groups of children: well-nourished (WN), well-nourished infected (WN-I), and malnourished infected (MN-I). In addition, the DNA migration length was evaluated in all groups before and after peroxide treatment. Comparison of mean migration lengths observed in WN and WN-I children showed significant differences at all times tested; between WN-I and MN-I differences were also observed, except after hydrogen peroxide exposure. This implies that lymphocytes of WN-I and MN-I children were equally sensitive to hydrogen peroxide. Nevertheless, the MN-I group clearly shows the greatest overall percentage of damaged cells at all times tested. In relation to repair capacity, at 5 min it was approximately 30% in both groups of well-nourished children, but only 20% in MN-I; 15 min after exposure, repair capacity increased to 51% in well-nourished children but only to 31% in MN-I; and at 60 min this capacity increased to 82% in well-nourished but only to 55% in MN-I. These data indicate that lymphocytes of malnourished children show a decreased capacity to repair hydrogen peroxide-induced DNA damage compared to that of well-nourished controls. This reflects that only malnutrition is associated with decreased DNA repair capacity. Additionally, the data confirm that severe infection and malnutrition are two factors clearly associated with increased DNA damage.
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Affiliation(s)
- C González
- Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana-Iztapalapa, México Distrito Federal, Mexico.
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21
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Chaubey RC, Bhilwade HN, Rajagopalan R, Bannur SV. Gamma ray induced DNA damage in human and mouse leucocytes measured by SCGE-Pro: a software developed for automated image analysis and data processing for Comet assay. Mutat Res 2001; 490:187-97. [PMID: 11342244 DOI: 10.1016/s1383-5718(00)00166-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The studies reported in this communication had two major objectives: first to validate the in-house developed SCGE-Pro: a software developed for automated image analysis and data processing for Comet assay using human peripheral blood leucocytes exposed to radiation doses, viz. 2, 4 and 8 Gy, which are known to produce DNA/chromosome damage using alkaline Comet assay. The second objective was to investigate the effect of gamma radiation on DNA damage in mouse peripheral blood leucocytes using identical doses and experimental conditions, e.g. lyses, electrophoretic conditions and duration of electrophoresis which are known to affect tail moment (TM) and tail length (TL) of comets. Human and mouse whole blood samples were irradiated with different doses of gamma rays, e.g. 2, 4 and 8 Gy at a dose rate of 0.668Gy/min between 0 and 4 degrees C in air. After lyses, cells were electrophorased under alkaline conditions at pH 13, washed and stained with propidium iodide. Images of the cells were acquired and analyzed using in-house developed imaging software, SCGE-Pro, for Comet assay. For each comet, total fluorescence, tail fluorescence and tail length were measured. Increase in TM and TL was considered as the criteria of DNA damage. Analysis of data revealed heterogeneity in the response of leucocytes to gamma ray induced DNA damage both in human as well as in mouse. A wide variation in TM and TL was observed in control and irradiated groups of all the three donors. Data were analyzed for statistical significance using one-way ANOVA. Though a small variation in basal level of TM and TL was observed amongst human and mouse controls, the differences were not statistically significant. A dose-dependent increase in TM (P<0.001) and TL (P<0.001) was obtained at all the radiation doses (2-8 Gy) both in human and mouse leucocytes. However, there was a difference in the nature of dose response curves for human and mouse leucocytes. In human leucocytes, a linear increase in TM and TL was observed up to the highest radiation dose of 8 Gy. However, in case of mouse leucocytes, a sharp increase in TM and TL was observed only up to 4 Gy, and there after saturation ensued. In human samples, the dose response of both TM and TL showed best fits with linear model (r(TM)=0.999 and r(TL)=0.999), where as in mouse, the best fit was obtained with Sigmoid (Boltzman) model. From the present data on leucocytes with increase in TM and TL as the criteria of DNA damage, it appears that mouse is relatively more sensitive to radiation damage than humans.
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Affiliation(s)
- R C Chaubey
- Genetic Toxicology & Chromosome Studies Section, Cell Biology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
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22
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Buschini A, Anceschi E, Carlo-Stella C, Regazzi E, Rizzoli V, Poli P, Rossi C. Amifostine (WR-2721) selective protection against melphalan genotoxicity. Leukemia 2000; 14:1642-51. [PMID: 10995012 DOI: 10.1038/sj.leu.2401877] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Amifostine (WR-2721) is an aminothiol compound dephosphorylated at the tissue site by alkaline phosphatase to the active metabolite, which is able to inactivate electrophilic substances and scavenge free radicals. Amifostine effects against melphalan-induced DNA strand breaks were studied in normal human white blood cells (WBC) and K562 leukemic cells using the single cell gel electrophoresis (SCGE) or Comet assay, a reported method for measuring DNA damage in individual cells. Prior to treatment (1 h, 37 degrees C) with increasing doses of melphalan, with or without S9, the cells were treated (15 min, 37 degrees C) with a control medium or amifostine (3 mg/ml). Treatment of normal and leukemic cells with melphalan induced a dose-dependent 'comet formation'. Melphalan-induced DNA damage follows a normal distribution in WBC. On the other hand, in K562, a significant proportion of undamaged cells remains even with doses at which mean DNA damage is serious. Pretreatment with WR-2721 protects WBC, but not K562, against the genotoxic effect of melphalan. Amifostine might even strengthen the action of the antiblastic drug against K562 cells. S9 addition appears to enhance melphalan effectiveness. SCGE appears as a suitable primary screening method for in vitro and in vivo studies on drug-DNA interactions and their modulations by endogenous/exogenous factors.
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Affiliation(s)
- A Buschini
- Istituto di Genetica, Università di Parma, Italy
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23
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Palus J, Dziubałtowska E, Rydzyński K. DNA damage detected by the comet assay in the white blood cells of workers in a wooden furniture plant. Mutat Res 1999; 444:61-74. [PMID: 10477340 DOI: 10.1016/s1383-5718(99)00089-3] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The study was aimed at the assessment of genotoxic effects in workers of a wooden furniture manufacture, based on the level of DNA damage in white blood cells (WBC). The alkaline single cell gel electrophoresis assay (known as the comet assay) in individual cells was adapted for detecting damaged DNA in WBC. The level of DNA damage was determined as the percentage of cells with comets. It was assessed in cells before and after incubation in RPMI 1640 medium and CO(2) at 37 degrees C for 1 h to repair DNA breaks. Thirty-five woodworkers and 41 control subjects were studied. In the woodworkers, significantly more cells with DNA damage (21.5%) were observed than in the control persons (9.7%). A slight but significant decrease in the level of DNA damage was found in the WBC of woodworkers after incubation (17.2%). Significantly higher levels of damaged DNA was observed in woodworkers who either smoked (22.1%) or did not smoke cigarettes (20.8%) than in smokers (13.2%) and non-smokers (7.0%) from the control group. After incubation, a slight decrease in the level of DNA damage was found in both smoking and non-smoking woodworkers compared to the respective subjects in the control group. The increased levels of DNA damage observed in the woodworkers could be associated with the occupational exposure to wood dust in the furniture manufacture.
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Affiliation(s)
- J Palus
- Nofer Institute of Occupational Medicine, Department of Toxicology and Carcinogenesis, 8 Teresy Strasse, PO Box 199, 90-950, Lódź, Poland
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Rojas E, Lopez MC, Valverde M. Single cell gel electrophoresis assay: methodology and applications. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1999; 722:225-54. [PMID: 10068143 DOI: 10.1016/s0378-4347(98)00313-2] [Citation(s) in RCA: 322] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The single cell gel electrophoresis or Comet assay is a sensitive, reliable, and rapid method for DNA double- and single-strand breaks, alkali-labile sites and delayed repair site detection, in eukaryotic individual cells. Given its overall characteristics, this method has been widely used over the past few years in several different areas. In this paper we review the studies published to date about the principles, the basic methodology with currently used variations. We also explore the applications of this assay in: genotoxicology, clinical area, DNA repair studies, environmental biomonitoring and human monitoring.
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Affiliation(s)
- E Rojas
- Departamento de Genética y Toxicología Ambiental, Instituto de Investigaciones Biomedicas, UNAM, Mexico DF, Mexico
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25
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Gutiérrez S, Carbonell E, Galofré P, Creus A, Marcos R. The alkaline single-cell gel electrophoresis (SCGE) assay applied to the analysis of radiation-induced DNA damage in thyroid cancer patients treated with 131I. Mutat Res 1998; 413:111-9. [PMID: 9639687 DOI: 10.1016/s1383-5718(98)00010-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The alkaline single-cell gel electrophoresis (SCGE or Comet) assay appears to be a promising tool for measuring DNA damage at the individual cell level in both in vitro and in vivo studies. To provide further data on the possible applicability of this assay in human biomonitoring studies, we have evaluated the eventual genetic damage induced by therapeutic exposure to 131I, by measuring the Comet length and the amount of DNA damage in peripheral blood leukocytes from a group of 28 thyroid cancer patients who received 131I sodium iodide via oral administration. Blood samples were taken just before the treatment and 1 week after it. From the results obtained after radioiodine therapy, a small increase in the Comet length and in the grade of DNA damage is observed; however, this increase is not statistically significant because of inter-individual variability and the variable responses before and after 131I treatment. Considering our previous studies showing significant increases in the frequency of cytogenetic damage (when measured as micronuclei) in patients treated with relatively low doses of 131I, the results obtained in the present work by using the Comet assay could indicate that 1 week after the exposure most of the radioiodine-induced DNA lesions, that can be detected with this assay, have already been repaired.
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Affiliation(s)
- S Gutiérrez
- Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Edifici Cn, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
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26
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Van Goethem F, Lison D, Kirsch-Volders M. Comparative evaluation of the in vitro micronucleus test and the alkaline single cell gel electrophoresis assay for the detection of DNA damaging agents: genotoxic effects of cobalt powder, tungsten carbide and cobalt-tungsten carbide. Mutat Res 1997; 392:31-43. [PMID: 9269329 DOI: 10.1016/s0165-1218(97)00043-8] [Citation(s) in RCA: 153] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Although it is well known that micronuclei may arise from either DNA breakage leading to acentric chromosome fragments or from chromosome/chromatid lagging in anaphase, the ratio between the amount of DNA breakage induced and the frequency of micronuclei expressed in the following interphase is unclear. With the development of the alkaline single cell gel electrophoresis assay, which measures single strand and/or double strand breaks in a cell by cell approach, it is new possible to address this question at the cellular level. We therefore compared the genotoxic potential of pure cobalt powder (Co) and a cobalt-containing alloy, cobalt-tungsten carbide (WC-Co), involved in specific lung disorders, in parallel with the alkaline single cell gel electrophoresis (SCGE) assay (comet assay) and the cytokinesis-blocked micronucleus (MN) test, both carried out in vitro on isolated human leukocytes. The comet assay indicated that the WC-Co mixture produced a higher level of DNA damage than Co alone; WC alone was not able to induce a dose-dependent DNA breakage effect as was seen for Co and WC-Co. Results from the MN test confirmed these observations. It was clear that the clastogenic property of Co-containing dust is significantly enhanced when the Co metal is mixed with WC and suggested that their physicochemical characteristics may act as one of the important parameters responsible for the increased incidence of lung cancers observed in the population of hard metal workers. In agreement with data obtained in the same laboratory on liposoluble chemicals (PCBs and chlorinated aliphatic hydrocarbons) and from the literature, the results indicate that both the comet assay and the micronucleus test were able to detect differences in the genotoxic potential of the compounds studied. Although the micronucleus test seemed to be less sensitive to assess a synergistic DNA damaging potential of the mixture involved, it detects chromosomal aberrations (chromosome/genome mutations) and not just repairable DNA breakage or alkali-labile sites. Combination of the comet assay and the in vitro MN test might therefore be recommended for genotoxins to understand the mechanisms underlying mutagenicity and to assess the lowest efficient dose.
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Affiliation(s)
- F Van Goethem
- Laboratory of Antropogenetics, Faculty of Science, Free University Brussels (VUB), Belgium.
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Visvardis EE, Tassiou AM, Piperakis SM. Study of DNA damage induction and repair capacity of fresh and cryopreserved lymphocytes exposed to H2O2 and gamma-irradiation with the alkaline comet assay. Mutat Res 1997; 383:71-80. [PMID: 9042421 DOI: 10.1016/s0921-8777(96)00047-x] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The alkaline SCGE assay was evaluated for use with cryopreserved lymphocytes in order to obtain results similar to the freshly isolated ones. The induction of DNA damage as well as the repair capacity of gamma-rays and H2O2 exposed cryopreserved human lymphocytes was found to be the same to that of the freshly isolated. Human lymphocytes (fresh or cryopreserved) responded differently to the effects of gamma-irradiation if compared to the H2O2 treatment. The distribution of DNA damage among gamma-irradiated lymphocytes was more homogeneous compared to H2O2, both in freshly isolated and in cryopreserved cells. 2.4 micrograms/ml phytohemagglutinin at the start of a 2-h incubation in RPMI of cryopreserved samples gave similar DNA repair and distribution patterns to the 2-h post-exposure incubation of freshly isolated lymphocytes. H2O2-induced DNA damage was not repaired completely. However, the repair of gamma-rays-induced DNA damage was more efficient. These findings confirm the different mode of action of the two agents on the induction of DNA damage, as well as, the different response of the lymphocytes' DNA repair system.
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Affiliation(s)
- E E Visvardis
- Department of Biology, National Centre for Scientific Research Demokritos, Aghia Paraskevi, Athens, Greece
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