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

Citation
T. Kawata et al., High-LET radiation-induced aberrations in prematurely condensed G2 chromosomes of human fibroblasts, INT J RAD B, 76(7), 2000, pp. 929-937
Citations number
44
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Experimental Biology
Journal title
INTERNATIONAL JOURNAL OF RADIATION BIOLOGY
ISSN journal
0955-3002 → ACNP
Volume
76
Issue
7
Year of publication
2000
Pages
929 - 937
Database
ISI
SICI code
0955-3002(200007)76:7<929:HRAIPC>2.0.ZU;2-#
Abstract
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 w ere radiated with gamma-rays, energetic carbon (290 MeV/u), silicon (490 Me V/u) and iron (200 and 600 MeV/u). Chromosomes were prematurely condensed u sing calyculin A. Chromatid breaks and exchanges in G2 cells were scored. P CC 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-L ET irradiation consisted of two exponential components representing a rapid and a slow time constant. Chromatid breaks decreased rapidly during the fi rst 10 min after exposure, then continued to decrease at a slower rate. The rejoining kinetics were similar for exposure to each type of radiation. Ch romatid exchanges were also formed quickly. Compared to low-LET radiation, isochromatid breaks were produced more frequently and the proportion of unr ejoined breaks was higher for high-LET radiation. Conclusions: Compared with gamma-rays, isochromatid breaks were observed mo re frequently in high-LET irradiated samples, suggesting that an increase i n isochromatid breaks is a signature of high-LET radiation exposure.