@misc{oai:repo.qst.go.jp:00069752,
 author = {Suzuki, Masao and Tsuruoka, Chizuru and Kitamura, Hisashi and Hua, Liu Cui and Uchihori, Yukio and 鈴木 雅雄 and 鶴岡 千鶴 and 北村 尚 and 劉 翠華 and 内堀 幸夫},
 month = {May},
 note = {Purpose: To investigate cellular responses in normal human fibroblasts induced with low dose irradiations of qualitatively different radiation types. 
Methods: Normal human fibroblasts were pre-treated with low-fluence irradiations (~1mGy/7-8h) of 137Cs gamma rays, 241Am-Be neutrons (maximum energy ; 11.5MeV, average energy ; 5.0MeV), helium (LET=2.3keV/µm), carbon (LET=13.3keV/µm) and iron ions (LET=200keV/µm) before applying irradiation with a 200kV X-ray challenging dose (1.5Gy). The 3 different ion beams were produced by the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences. 
Results: There was no difference in X-ray-induced mutation frequency, which was detected with hprt locus detected as 6-thioguanine resistant clones, between un-pretreated and gamma-ray pre-treated cells. In the case of the pre-treatment with high-LET ions, mutation frequency was around 4.0 times higher in carbon- and 1.9 times higher in helium-ion pre-treated cells than in un-pretreated cells, while no difference was observed in iron-ion pre-treated cells. On the contrary, mutation frequency in cells pre-treated with neutrons was reduced at 15% of un-pretreated cells. To identify possible mechanism(s) of the observed cellular response, cells were treated with a specific inhibitor of gap-junction mediated cell-cell communication. The results clearly showed that the observed enhancement of X-ray-induced mutation frequency in cells pre-treated with helium and carbon ions was reduced at the control level and reduction in cells pre-treated with neutrons was came back to the control level. 
Conclusion: There is evidence that gap-junction mediated cell-cell communication play an important role of inducing different cellular responses by pre-treatment with different radiation types., 第二回アジア放射線連合会議（2nd Asian Congress of Radiation Research）},
 title = {Dependence in bystander cellular responses in mutation induction on normal human fibroblasts induced by the pre-treatment with different radiation types},
 year = {2009}
}