G2 chromatid damage and repair kinetics in normal human fibroblast cells exposed to low- or high-LET radiation.
Radiation-induced chromosome damage can be measured in interphase using the Premature Chromosome Condensation (PCC) technique. With the introduction of a new PCC technique using the potent phosphatase inhibitor calyculin-A, chromosomes can be condensed within five minutes, and it is now possible to examine the early damage induced by radiation. Using this method, it has been shown that high-LET radiation induces a higher frequency of chromatid breaks and a much higher frequency of isochromatid breaks than low-LET radiation. The kinetics of chromatid break rejoining consists of two exponential components representing a rapid and a slow time constant, which appears to be similar for low- and high-LET radiations. However, after high-LET radiation exposures, the rejoining process for isochromatid breaks influences the repair kinetics of chromatid-type breaks, and this plays an important role in the assessment of chromatid break rejoining in the G2 phase of the cell cycle.
Kawata
T
T
Department of Radiology, Graduate School of Medicine, Chiba, Japan. tkawata@med.m.chiba-u.ac.jp
Ito
H
H
Uno
T
T
Saito
M
M
Yamamoto
S
S
Furusawa
Y
Y
Durante
M
M
George
K
K
Wu
H
H
Cucinotta
F A
FA
D000818:Animals; D016466:CHO Cells / Q000528:radiation effects / Q000648:ultrastructure; D002478:Cells, Cultured / Q000528:radiation effects / Q000648:ultrastructure; D002842:Chromatids / Q000528:radiation effects / Q000648:ultrastructure; D002869:Chromosome Aberrations; D019457:Chromosome Breakage; D002877:Chromosomes, Human / Q000528:radiation effects* / Q000648:ultrastructure; D006224:Cricetinae; D003412:Cricetulus; D004260:DNA Repair / Q000502:physiology*; D004307:Dose-Response Relationship, Radiation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000528:radiation effects / Q000648:ultrastructure; D016195:G2 Phase / Q000528:radiation effects; D005720:Gamma Rays / Q000009:adverse effects; D006801:Humans; D007700:Kinetics; D018499:Linear Energy Transfer; D008214:Lymphocytes / Q000528:radiation effects / Q000648:ultrastructure; D008387:Marine Toxins; D009502:Neutrons / Q000009:adverse effects; D010080:Oxazoles / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors
D004791:Enzyme Inhibitors; D008387:Marine Toxins; D010080:Oxazoles; C059041:calyculin A; D010749:Phosphoprotein Phosphatases