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Sato, Tatsuhiko; Hamada, Nobuyuki*
no journal, ,
We here propose a new model assembly for estimating the surviving fraction of cells irradiated with various types of ionizing radiation, considering both targeted and nontargeted effects in the same framework. The probability densities of specific energies in two scales, which are the cell nucleus and its substructure called a domain, were employed as the physical index for characterizing the radiation fields. In the model assembly, our previously established double stochastic microdosimetric kinetic (DSMK) model was used to express the targeted effect, whereas a newly developed model was used to express the nontargeted effect. The radioresistance caused by overexpression of anti-apoptotic protein Bcl-2 known to frequently occur in human cancer was also considered by introducing the concept of the adaptive response in the DSMK model. The accuracy of the model assembly was examined by comparing the computationally and experimentally determined surviving fraction of Bcl-2 cells (Bcl-2 overexpressing HeLa cells) and Neo cells (neomycin resistant gene-expressing HeLa cells) irradiated with microbeam or broadbeam of energetic heavy ions, as well as the WI-38 normal human fibroblasts irradiated with X-ray microbeam. The model assembly reproduced very well the experimentally determined surviving fraction over a wide range of dose and linear energy transfer (LET) values. Our newly established model assembly will be worth being incorporated into treatment planning systems for heavy-ion therapy, brachytherapy, and boron neutron capture therapy, given critical roles of the frequent Bcl-2 overexpression and the nontargeted effect in estimating therapeutic outcomes and harmful effects of such advanced therapeutic modalities.
Ouchi, Noriyuki
no journal, ,
no abstracts in English
Sakamoto, Fuminori; Kozai, Naofumi; Shiina, Kazuhiro; Tanaka, Kenji
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no abstracts in English
Hattori, Yuya; Yokoya, Akinari; Watanabe, Ritsuko
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no abstracts in English
Hattori, Yuya; Yokoya, Akinari; Watanabe, Ritsuko
no journal, ,
no abstracts in English
- and 
-rays from Cs-137Watanabe, Ritsuko; Kai, Takeshi; Yokoya, Akinari
no journal, ,
no abstracts in English
Ohshima, Yasuhiro; Tsukimoto, Mitsutoshi*; Tsushima, Yoshito*; Ishioka, Noriko
no journal, ,
no abstracts in English
following irradiationSuzuki, Michiyo; Sakashita, Tetsuya; Hattori, Yuya; Kobayashi, Yasuhiko
no journal, ,
no abstracts in English
based on taxisSakashita, Tetsuya
no journal, ,
show the unique behavior against various stimuli, e.g. mechanical, ionic, thermal, oxgenic and food signals. It is well known that these behavior is related to the specific signaling pathway or neurons. On the other hand, we have studied on the effects of ionizing radiation on the salt chemotaxis learning in , and found a specific gene related to the radiation responses. In this presentation, I will discuss on the relation between behavior, survival and ionizing radiation.
Akamatsu, Ken; Shikazono, Naoya
no journal, ,
no abstracts in English
Shikazono, Naoya; Akamatsu, Ken
no journal, ,
no abstracts in English
Yamamoto, Satoshi; Izumi, Yudai; Fujii, Kentaro; Yokoya, Akinari
no journal, ,
no abstracts in English
Yokoya, Akinari; Suzuki, Keiji*
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no abstracts in English
Yokoya, Akinari; Narita, Ayumi; Kaminaga, Kiichi; Kanari, Yukiko; Sakamoto, Yuka; Noguchi, Miho; Usami, Noriko*; Kobayashi, Katsumi*; Fujii, Kentaro; Suzuki, Keiji*
no journal, ,
no abstracts in English
Fujii, Kentaro; Izumi, Yudai; Narita, Ayumi; Yokoya, Akinari; Herv
du Penhoat, M.-A.*; Ghose, K.*; Vuilleumier, R.*; Gaigeot, M.-P.*; Politis, M.-F.*
no journal, ,
no abstracts in English
Izumi, Yudai; Yamamoto, Satoshi*; Fujii, Kentaro; Yokoya, Akinari
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no abstracts in English
Funayama, Tomoo; Yokota, Yuichiro; Sakashita, Tetsuya; Suzuki, Michiyo; Kobayashi, Yasuhiko
no journal, ,
To explore the single ion hit effect of heavy-ion the cells, we established a method to detect focusing beam spot under the microscopy, and carried out an irradiation of cells by moving cells to the position of focusing beam spot one by one. However, according to the speed limitation of the mechanical stage, the throughput of the irradiation is still comparable with that of the collimating system. To improve the throughput, we next carried out a development of a method to irradiate cells with a scanned beam. The HeLa cells were inoculated on a CR-39 film, and irradiated with scanned neon microbeam. After irradiation, the hit positions of the ion were visualized as etched pits, and the cells were stained with the -H2AX antibody. We found the correspondence of the distribution pattern of the etch pits, the cell positions and the -H2AX foci. Thus we concluded that the developed method can irradiate cells rapidly and accurately with the focusing heavy-ion microbeam.
Ikeda, Hiroko; Yokota, Yuichiro; Funayama, Tomoo; Kanai, Tatsuaki*; Nakano, Takashi*; Kobayashi, Yasuhiko
no journal, ,
Human lung normal fibroblasts WI-38 and human lung cancer cells H1299/wt
were used. Cells were irradiated with carbon-ion broad beams (LET=108 keV/ 
m), then survival rates of bystander cells after co-culture with irradiated cells were measured using colony formation assay. The survival rates of non-irradiated H1299/wt cells co-cultured with 0.13 Gy irradiated WI-38 increased after 6 and 24 h of co-culture. On the other hand, the bystander cells co-cultured with 0.5 Gy irradiated WI-38 showed decreased survival rates. The survival rates of bystander H1299/wt cells showed a tendency to increase by the addition of Carboxy-PTIO to the co-culture medium, when co-cultured with 0.5 Gy irradiated WI-38. From these results, reduction of survival rates is likely to be caused by NO radical as a mediator in bystander effects between lung normal and cancer cells. However, it is suggested that there might be other signals participated in an increase of survival rates.
Kaminaga, Kiichi; Kanari, Yukiko; Sakamoto, Yuka; Narita, Ayumi; Usami, Noriko*; Kobayashi, Katsumi*; Noguchi, Miho; Yokoya, Akinari
no journal, ,
no abstracts in English
Kanari, Yukiko; Kaminaga, Kiichi; Narita, Ayumi; Usami, Noriko*; Suzuki, Keiji*; Yokoya, Akinari
no journal, ,
no abstracts in English