Induction of genomic instability in TK6 human lymphoblasts exposed to 137Cs gamma radiation: comparison to the induction by exposure to accelerated 56Fe particles.
The induction of genomic instability in TK6 human lymphoblasts by exposure to (137)Cs gamma radiation was investigated by measuring the frequency and characteristics of unstable clones isolated approximately 36 generations after exposure. Clones surviving irradiation and control clones were analyzed for 17 characteristics including chromosomal aberrations, growth defects, alterations in response to a second irradiation, and mutant frequencies at the thymidine kinase and Na(+)/K(+) ATPase loci. Putative unstable clones were defined as those that exhibited a significant alteration in one or more characteristics compared to the controls. The frequency and characteristics of the unstable clones were compared in clones exposed to (137)Cs gamma rays or (56)Fe particles. The majority of the unstable clones isolated after exposure to either gamma rays or (56)Fe particles exhibited chromosomal instability. Alterations in growth characteristics, radiation response and mutant frequencies occurred much less often than cytogenetic alterations in these unstable clones. The frequency and complexity of the unstable clones were greater after exposure to (56)Fe particles than to gamma rays. Unstable clones that survived 36 generations after exposure to gamma rays exhibited increases in the incidence of dicentric chromosomes but not of chromatid breaks, whereas unstable clones that survived 36 generations after exposure to (56)Fe particles exhibited increases in both chromatid and chromosome aberrations.
Evans
Helen H
HH
Case Western Reserve University, Cleveland, Ohio 44106-4942, USA. hhe@po.cwru.edu
Horng
Min-Fen
MF
Ricanati
Marlene
M
Diaz-Insua
M
M
Jordan
Robert
R
Schwartz
Jeffrey L
JL
D002478:Cells, Cultured; D002588:Cesium Radioisotopes; D002869:Chromosome Aberrations / Q000528:radiation effects*; D005720:Gamma Rays; D006801:Humans; D007501:Iron; D018499:Linear Energy Transfer; D008214:Lymphocytes / Q000528:radiation effects* / Q000648:ultrastructure; D010641:Phenotype; D017382:Reactive Oxygen Species
D002588:Cesium Radioisotopes; D017382:Reactive Oxygen Species; D007501:Iron