Extrapolation of the dna fragment-size distribution after high-dose irradiation to predict effects at low doses.
Radiat Res
; 156(5 Pt 2): 594-7, 2001 Nov.
Article
de En
| MEDLINE
| ID: mdl-11604078
ABSTRACT
The patterns of DSBs induced in the genome are different for sparsely and densely ionizing radiations In the former case, the patterns are well described by a random-breakage model; in the latter, a more sophisticated tool is needed. We used a Monte Carlo algorithm with a random-walk geometry of chromatin, and a track structure defined by the radial distribution of energy deposition from an incident ion, to fit the PFGE data for fragment-size distribution after high-dose irradiation. These fits determined the unknown parameters of the model, enabling the extrapolation of data for high-dose irradiation to the low doses that are relevant for NASA space radiation research. The randomly-located-clusters formalism was used to speed the simulations. It was shown that only one adjustable parameter, Q, the track efficiency parameter, was necessary to predict DNA fragment sizes for wide ranges of doses. This parameter was determined for a variety of radiations and LETs and was used to predict the DSB patterns at the HPRT locus of the human X chromosome after low-dose irradiation. It was found that high-LET radiation would be more likely than low-LET radiation to induce additional DSBs within the HPRT gene if this gene already contained one DSB.
Mots clés
Recherche sur Google
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Altération de l'ADN
/
ADN
/
Relation dose-effet des rayonnements
Type d'étude:
Health_economic_evaluation
/
Prognostic_studies
/
Risk_factors_studies
Limites:
Humans
Langue:
En
Journal:
Radiat Res
Année:
2001
Type de document:
Article
Pays d'affiliation:
États-Unis d'Amérique