The bystander effects induced by medium from human hepatoma SMMC-7721 and adenocarcinoma F56 cells irradiated with carbon ions were investigated. It was found that the survival fraction (SF) of the irradiated cells de...The bystander effects induced by medium from human hepatoma SMMC-7721 and adenocarcinoma F56 cells irradiated with carbon ions were investigated. It was found that the survival fraction (SF) of the irradiated cells decreased exponentially along with the increased dose. SMMC-7721 cells were more radiosensitive than F56 cells. The plating efficiency (PE) of the non-irradiated cells treated with irradiated conditioned medium (ICM) was obvi-ously lower than the PE of control cells for SMMC-7721 cells but not for F56 cells. Moreover, the reduced PE and SF by ICM treatment were more significant for 1Gy irradiation than for 6Gy irradiation on SMMC-7721 cells. These results suggest that the irradiated cells can secrete factor(s) into medium that is cytotoxic to bystander non-irradiated cells. The bystander effects are dependent on cell genotype presented at the time of irradiation and radiation dose. This makes impact on the precise estimation of the effects of radiation and tumor radiotherapy.展开更多
The developed track detector consists of two parts: a small drift region to obtain a good tracking and a relatively large multiplication region for getting an enough high gain at low pressure. All the track detector c...The developed track detector consists of two parts: a small drift region to obtain a good tracking and a relatively large multiplication region for getting an enough high gain at low pressure. All the track detector can be moved in the direction perpendicular to the beam by means of a micrometric screw. An automatic system allows the counting gas to flow continuously at constant pressure through the detector during the measurements. The system can measure ionization distributions at a few nanometer range.展开更多
Inhibition effects, control probabilities and pathology tissue changes of mouse transplanted tumors S180 after irradiation with 50 MeVu 12C6+ ions are reported. Doses of single irradiation were 0.5, 1, 2, 5, 10, 20, 4...Inhibition effects, control probabilities and pathology tissue changes of mouse transplanted tumors S180 after irradiation with 50 MeVu 12C6+ ions are reported. Doses of single irradiation were 0.5, 1, 2, 5, 10, 20, 40 Gy, respectivelyl at a dose rate of 3 Gy/min. Observing time was 24 days. The results show that each group had significant inhibition action on S180 tumors and all inhibitory probabilities were more than 90%; the initial time of inducing tumor inhibition effects were within one week in high dose groups （20, 40 Gy）, and after two weeks in medium dose groups （5, 10 Gy） and low dose groups （0.5, 1, 2 Gy）; also, inhibitory effects in high dose groups were obviously greater than other groups （p <0.05）; tumor control probabilities were different in each group) those in high dose groups （20, 40 Gy） were higher and TCD50 （50% tumor control dose） was 20Gy; the results for curing tumors are different in different doses; pathology inspection presented here were tumor tissue necrosis and degeneration in each dose group and they depended on doses.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No.10105012) and the Major Subject of National Natural Science Foundation of China (10335050)
文摘The bystander effects induced by medium from human hepatoma SMMC-7721 and adenocarcinoma F56 cells irradiated with carbon ions were investigated. It was found that the survival fraction (SF) of the irradiated cells decreased exponentially along with the increased dose. SMMC-7721 cells were more radiosensitive than F56 cells. The plating efficiency (PE) of the non-irradiated cells treated with irradiated conditioned medium (ICM) was obvi-ously lower than the PE of control cells for SMMC-7721 cells but not for F56 cells. Moreover, the reduced PE and SF by ICM treatment were more significant for 1Gy irradiation than for 6Gy irradiation on SMMC-7721 cells. These results suggest that the irradiated cells can secrete factor(s) into medium that is cytotoxic to bystander non-irradiated cells. The bystander effects are dependent on cell genotype presented at the time of irradiation and radiation dose. This makes impact on the precise estimation of the effects of radiation and tumor radiotherapy.
文摘The developed track detector consists of two parts: a small drift region to obtain a good tracking and a relatively large multiplication region for getting an enough high gain at low pressure. All the track detector can be moved in the direction perpendicular to the beam by means of a micrometric screw. An automatic system allows the counting gas to flow continuously at constant pressure through the detector during the measurements. The system can measure ionization distributions at a few nanometer range.
基金President Special Foundation of the Chinese Academy of Sciences
文摘Inhibition effects, control probabilities and pathology tissue changes of mouse transplanted tumors S180 after irradiation with 50 MeVu 12C6+ ions are reported. Doses of single irradiation were 0.5, 1, 2, 5, 10, 20, 40 Gy, respectivelyl at a dose rate of 3 Gy/min. Observing time was 24 days. The results show that each group had significant inhibition action on S180 tumors and all inhibitory probabilities were more than 90%; the initial time of inducing tumor inhibition effects were within one week in high dose groups （20, 40 Gy）, and after two weeks in medium dose groups （5, 10 Gy） and low dose groups （0.5, 1, 2 Gy）; also, inhibitory effects in high dose groups were obviously greater than other groups （p <0.05）; tumor control probabilities were different in each group) those in high dose groups （20, 40 Gy） were higher and TCD50 （50% tumor control dose） was 20Gy; the results for curing tumors are different in different doses; pathology inspection presented here were tumor tissue necrosis and degeneration in each dose group and they depended on doses.
