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McArt DG, McKerr G, Saetzler K, Howard CV, Downes CS, Wasson GR. Comet sensitivity in assessing DNA damage and repair in different cell cycle stages. Mutagenesis 2010; 25:299-303. [DOI: 10.1093/mutage/geq006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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McGlynn AP, Wasson GR, O'Reilly S, McKelvey-Martin VJ, McNulty H, Strain JJ, McKerr G, Mullan F, Mahmud N, Scott J, Weir DG, Downes CS. Detection of replicative integrity in small colonic biopsies using the BrdUrd comet assay. Br J Cancer 2003; 88:895-901. [PMID: 12644827 PMCID: PMC2377088 DOI: 10.1038/sj.bjc.6600836] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The alkaline single-cell gel electrophoresis or comet assay is a relatively simple method of measuring DNA single-strand breaks and alkali-labile sites in individual cells. Previously, we have used a combination of this with bromodeoxyuridine labelling of DNA and immunolocalisation of the BrdUrd to show that DNA replicative integrity can be assessed in single cultured cells. This study demonstrates the application of the technique to single cells derived from small human colonic biopsies isolated at routine endoscopy. A high level of reproducibility within replicate comet slides and between comet slides prepared from various colonic sites within a single patient is shown. Preliminary results demonstrate that defects in replication can be detected in tumour and premalignant colonic tissue adjacent to the tumour, suggesting that alterations in replicative integrity are an early event in neoplasia, appearing in premalignant mucosal cells. This development deems the BrdUrd comet assay suitable as an ex vivo molecular end point that can be measured easily in tissue collected by biopsy at routine colonic endoscopy. Thus, the BrdUrd comet assay has the potential to facilitate trial investigations of diet- or environment-related factors that may affect replicative integrity in the colon and provides a novel biomarker for colon carcinogenesis.
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Affiliation(s)
- A P McGlynn
- Cancer and Ageing Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, County Londonderry, Northern Ireland, UK
| | - G R Wasson
- Cancer and Ageing Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, County Londonderry, Northern Ireland, UK
| | - S O'Reilly
- Department of Clinical Medicine, St James' Hospital, Dublin 8, Ireland
| | - V J McKelvey-Martin
- Cancer and Ageing Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, County Londonderry, Northern Ireland, UK
| | - H McNulty
- Cancer and Ageing Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, County Londonderry, Northern Ireland, UK
| | | | - G McKerr
- Cancer and Ageing Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, County Londonderry, Northern Ireland, UK
| | - F Mullan
- Causeway Trust, Coleraine, County Londonderry, Northern Ireland, UK
| | - N Mahmud
- Department of Clinical Medicine, St James' Hospital, Dublin 8, Ireland
| | - J Scott
- Department of Biochemistry, Trinity College, Dublin 2, Ireland
| | - D G Weir
- Department of Clinical Medicine, St James' Hospital, Dublin 8, Ireland
| | - C S Downes
- Cancer and Ageing Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, County Londonderry, Northern Ireland, UK
- Cancer and Ageing Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, County Londonderry, Northern Ireland, UK. E-mail:
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Brennan LA, Morris GM, Wasson GR, Hannigan BM, Barnett YA. The effect of vitamin C or vitamin E supplementation on basal and H2O2-induced DNA damage in human lymphocytes. Br J Nutr 2000; 84:195-202. [PMID: 11029970 DOI: 10.1017/s0007114500001422] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
There is a wealth of epidemiological information on antioxidants and their possible prevention of disease progression but very little of the research on antioxidants has involved intervention studies. In this study, the potential protective effect of vitamin C or E supplementation in vivo against endogenous and H2O2-induced DNA damage levels in lymphocytes was assessed. The supplementation involved fourteen healthy male and female non-smokers mean age 25-53 (SD 1.82) years, who were asked to supplement an otherwise unchanged diet with 1000 mg vitamin C daily for 42 d or 800 mg vitamin E daily for 42 d. DNA damage in H2O2-treated peripheral blood lymphocytes (PBL) and untreated PBL before and after supplementation, and during a 6-week washout period was assessed using an ELISA. At each sampling time-point, the red cell concentrate activities of superoxide dismutase, catalase and glutathione peroxidase were also determined. Supplementation with vitamin C or vitamin E decreased significantly H2O2-induced DNA damage in PBL, but had no effect on endogenous levels of DNA damage. The activities of the antioxidant enzymes superoxide dismutase and glutathione peroxidase were suppressed during the supplementation period. These supplementation regimens may be used to limit the possible adverse effects of reactive oxygen species (including those produced during the course of an immune response) on lymphocytes in vivo, and so help to maintain their functional capacity.
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Affiliation(s)
- L A Brennan
- Cancer and Ageing Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland
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