Effects of LET on oxygen-dependent and-independent generation of hydrogen peroxide in water irradiated by carbon-ion beams.
Free Radic Res
; 55(6): 714-719, 2021 Jun.
Article
em En
| MEDLINE
| ID: mdl-34519601
ABSTRACT
Linear energy transfer (LET) dependence of yields of O2-dependent and O2-independent hydrogen peroxide (H2O2) in water irradiated by ionizing radiation was investigated. The radiation-induced hydroxyl radical (â¢OH) generation in an aqueous solution was reported to occur in two different localization densities, the milli-molar (relatively sparse) and/or molar (markedly-dense) levels. In the milli-molar-level â¢OH generation atmosphere, â¢OH generated at a molecular distance of â¼7 nm are likely unable to interact. However, in the molar-level â¢OH generation atmosphere, several â¢OH were generated with a molecular distance of 1 nm or less, and two â¢OH can react to directly make H2O2. An aliquot of ultra-pure water was irradiated by 290-MeV/nucleon carbon-ion beams at the Heavy-Ion Medical Accelerator in Chiba (HIMAC, NIRS/QST, Chiba, Japan). Irradiation experiments were performed under aerobic or hypoxic (<0.5% oxygen) conditions, and several LET conditions (13, 20, 40, 60, 80, or >100 keV/µm). H2O2 generation in irradiated samples was estimated by three methods. The amount of H2O2 generated per dose was estimated and compared. O2-independent H2O2 generation, i.e. H2O2 generation under hypoxic conditions, increased with increasing LET. On the other hand, the O2-dependent H2O2 generation, i.e. subtraction of H2O2 generation under hypoxic conditions from H2O2 generation under aerobic conditions, decreased with increasing LET. This suggests that the markedly-dense â¢OH generation is positively correlated with LET. High-LET beams generate H2O2 in an oxygen-independent manner.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oxigênio
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Carbono
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Água
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Transferência Linear de Energia
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Peróxido de Hidrogênio
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Íons
Idioma:
En
Revista:
Free Radic Res
Assunto da revista:
BIOQUIMICA
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Japão