Dose rate effects on cell killing by γ-irradiation in ataxia telangiectasia lymphoblastoid cells

To investigate the dependency of dose rate effect on ATM gene , loss of the clonogenicity of lymphoblastoid cells derived from a patient with ataxia telangiectasia(ATI-l) was studied after exposure to γ-rays at dose rates of 30 Gy/h, 0.21 Gy/h and 0.0048 Gy/h. AT1-1 cells were very sensitive to kill...

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Published in:JOURNAL OF RADIATION RESEARCH 1998, Vol.39 (4), p.401-401
Main Authors: Ikuko FURUNO-FUKUSHI, Kouichi TATSUMI
Format: Article
Language:Japanese
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Summary:To investigate the dependency of dose rate effect on ATM gene , loss of the clonogenicity of lymphoblastoid cells derived from a patient with ataxia telangiectasia(ATI-l) was studied after exposure to γ-rays at dose rates of 30 Gy/h, 0.21 Gy/h and 0.0048 Gy/h. AT1-1 cells were very sensitive to killing by high dose rate γ-rays, and showed a comparable sensitivity to those for SCID (XRCC7) and LX830 (XRCC4) cells. Survival curves showed an increase in D_0 when AT1-1 cells were irradiated at the lower dose rates compared to the high dose rate. We have determined that SCID and LX830 cells were defective in the repair of DNA double strand breaks(DSBs) and that the two cell lines failed to show the dose rate effect of γ-rays. AT cells have been believed to result from cell-cycle checkpoint defects, especially since no substantial defect in the capacity to rejoin DNA DSBs has been successfully detected for AT cells following irradiation. Hence, we suggest that the dose rate effect on cell killing by γ-rays is strongly associated with the efficient repair processes of DNA DSBs.
ISSN:0449-3060