Cellular responses to low dose heavy-ion exposure in human cells.
The human lymphoblastoid cell line TK6 was used to study the cellular responses after low-dose (100, 200, 500 mGy) or high-dose (3 Gy) of X rays, C (22 keV.micron-1) and Fe (1000 keV.micron-1) ion exposures. p53 protein induction in individual cells was determined by indirect immunofluorescence staining. Cell-cycle progression after heavy-ion exposure was determined by using a laser scanning cytometer. A characteristic pattern of cell-cycle progression was observed with 3 Gy exposure of Fe ions but not with 100 mGy. Similarly such a pattern with 100 mGy C ion exposure did not match that with 3 Gy. The proportion of p53-induced cells is proportional to the probability of cell being hit by a primary heavy ion. The observed low-dose effect can be reflected in the probability of a hit, although detailed nature about their energy deposition must be considered for more precise estimation of such an effect. New detection methodology must be developed for identification of heavy-ion specific cellular responses.
Morimoto
S
S
Division of Radioisotope Technology, Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Goto
S
S
Kato
T
T
Izumi
M
M
Komiyama-Kobayashi
M
M
Fukunishi
N
N
Honma
M
M
Hanaoka
F
F
Yatagai
F
F
D002453:Cell Cycle / Q000528:radiation effects; D002460:Cell Line; D004307:Dose-Response Relationship, Radiation; D020450:Heavy Ions; D006801:Humans; D008214:Lymphocytes / Q000166:cytology / Q000528:radiation effects*