High-LET radiation-induced aberrations in prematurely condensed G2 chromosomes of human fibroblasts

Purpose : To determine the number of initial chromatid breaks induced by low- or high-LET irradiations, and to compare the kinetics of chromatid break rejoining for radiations of different quality. Material and methods : Exponentially growing human fibroblast cells AG1522 were irradiated with γ-rays...

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Bibliographic Details
Published in:International journal of radiation biology 2000, Vol.76 (7), p.929-937
Main Author: Kawata, E. Gotoh, M. Durante, H. Wu, K. George, Y. Furusawa, F. A. Cucinotta, T.
Format: Article
Language:English
Subjects:
Biological and medical sciences
Cell Line
Chromatids - radiation effects
Chromatin. Chromosome
Chromosome Aberrations
Fibroblasts - radiation effects
Fundamental and applied biological sciences. Psychology
G2 Phase - radiation effects
Humans
Life Sciences (General)
Linear Energy Transfer
Molecular and cellular biology
Molecular genetics
Relative Biological Effectiveness
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Summary:Purpose : To determine the number of initial chromatid breaks induced by low- or high-LET irradiations, and to compare the kinetics of chromatid break rejoining for radiations of different quality. Material and methods : Exponentially growing human fibroblast cells AG1522 were irradiated with γ-rays, energetic carbon (290 MeV/u), silicon (490 MeV/u) and iron (200 and 600 MeV/u). Chromosomes were prematurely condensed using calyculin A. Chromatid breaks and exchanges in G2 cells were scored. PCC were collected after several post-irradiation incubation times, ranging from 5 to 600 min. Results : The kinetics of chromatid break rejoining following low-or high-LET irradiation consisted of two exponential components representing a rapid and a slow time constant. Chromatid breaks decreased rapidly during the first 10 min after exposure, then continued to decrease at a slower rate. The rejoining kinetics were similar for exposure to each type of radiation. Chromatid exchanges were also formed quickly. Compared to low-LET radiation, isochromatid breaks were produced more frequently and the proportion of unrejoined breaks was higher for high-LET radiation. Conclusions : Compared with γ-rays, isochromatid breaks were observed more frequently in high-LET irradiated samples, suggesting that an increase in isochromatid breaks is a signature of high-LET radiation exposure.
ISSN:0955-3002
1362-3095
DOI:10.1080/09553000050050945