| Minor contribution of direct ionization to DNA base damage inducedby heavy ions. | |
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MedLine Citation:
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PMID: 16546910 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: The deleterious processes triggered by heavy ions on DNA were studied through the determination of the yield of a series of oxidized bases. Emphasis was placed on the estimation of the respective contribution of direct ionization and indirect effects, mostly by comparison with low linear energy transfer (LET) gamma-rays. MATERIAL AND METHODS: DNA samples and human monocytes were exposed either to gamma-rays emitted by a (60)Co source or to (12)C(6+) or (36)Ar(18+) ions. The levels of thymidine and 2'-deoxyguanosine oxidation products were determined by liquid chromatography coupled to tandem mass spectrometry subsequently to DNA digestion into nucleosides. RESULTS: The yields of thymidine lesions were similar to those of 8-oxo-7,8-dihydro-2'-deoxyguanosine within isolated DNA exposed either to gamma-rays or argon ions. Addition of spermine and Tris aimed at minimizing the indirect effect modified this ratio to the same extent with both types of radiation. In cells, the level of radiation-induced base damage was found to be correlated with the radiolytic yield of degrees OH that depends on the LET of the particle. In addition, radiation-induced thymidine and 2'-deoxyguanosine lesions were produced in similar amounts. In contrast, oxidation of 2'-deoxyguanosine was the main process when ionization was triggered in cellular DNA by ultraviolet laser-induced biphotonic processes. CONCLUSIONS: Predominant oxidation of 2'-deoxyguanosine is expected to be the hallmark of direct DNA ionization. The observation that thymidine and 2'-deoxyguanosine are equally damaged rules out a major contribution of the direct ionization in radiation-induced base damage to both isolated and cellular DNA by heavy ions. Dependence of the yield of lesions on the LET provides further support for this conclusion. |
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Authors:
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Thierry Douki; Jean-Luc Ravanat; Jean-Pierre Pouget; Isabelle Testard; Jean Cadet |
Publication Detail:
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Type: Comparative Study; Journal Article |
Journal Detail:
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Title: International journal of radiation biology Volume: 82 ISSN: 0955-3002 ISO Abbreviation: Int. J. Radiat. Biol. Publication Date: 2006 Feb |
Date Detail:
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Created Date: 2006-03-20 Completed Date: 2006-06-01 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8809243 Medline TA: Int J Radiat Biol Country: England |
Other Details:
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Languages: eng Pagination: 119-27 Citation Subset: IM; S |
Affiliation:
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Laboratoire 'Lésions des Acides Nucléiques', Service de Chimie Inorganique et Biologique UMR-E 3 CEA-UJF, CEA/DSM/Département de Recherche Fondamentale sur la Matière Condensée, CEA-Grenoble, Grenoble, France. tdouki@cea.fr |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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DNA
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chemistry*,
radiation effects* DNA Damage* Dose-Response Relationship, Radiation Gamma Rays* Heavy Ions* Nucleotides / chemistry*, radiation effects* Radiation Dosage |
| Chemical | |
Reg. No./Substance:
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0/Nucleotides; 9007-49-2/DNA |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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