The Experts below are selected from a list of 21207 Experts worldwide ranked by ideXlab platform
Shinichiro Masunaga - One of the best experts on this subject based on the ideXlab platform.
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radiobiologic significance of response of intratumor quiescent cells in vivo to accelerated carbon ion Beams compared with γ rays and reactor Neutron Beams
International Journal of Radiation Oncology Biology Physics, 2008Co-Authors: Shinichiro Masunaga, Koichi Ando, Akiko Uzawa, Ryoichi Hirayama, Yoshiya Furusawa, Sachiko Koike, Yoshinori Sakurai, Kenji Nagata, Minoru Suzuki, Genro KashinoAbstract:Purpose To clarify the radiosensitivity of intratumor quiescent cells in vivo to accelerated carbon ion Beams and reactor Neutron Beams. Methods and Materials Squamous cell carcinoma VII tumor-bearing mice were continuously given 5-bromo-2′-deoxyuridine to label all intratumor proliferating cells. Next, they received accelerated carbon ion or γ-ray high-dose-rate (HDR) or reduced-dose-rate (RDR) irradiation. Other tumor-bearing mice received reactor thermal or epithermal Neutrons with RDR irradiation. Immediately after HDR and RDR irradiation or 12 h after HDR irradiation, the response of quiescent cells was assessed in terms of the micronucleus frequency using immunofluorescence staining for 5-bromo-2′-deoxyuridine. The response of the total (proliferating plus quiescent) tumor cells was determined from the 5-bromo-2′-deoxyuridine nontreated tumors. Results The difference in radiosensitivity between the total and quiescent cell populations after γ-ray irradiation was markedly reduced with reactor Neutron Beams or accelerated carbon ion Beams, especially with a greater linear energy transfer (LET) value. Clearer repair in quiescent cells than in total cells through delayed assay or a decrease in the dose rate with γ-ray irradiation was efficiently inhibited with carbon ion Beams, especially with a greater LET. With RDR irradiation, the radiosensitivity to accelerated carbon ion Beams with a greater LET was almost similar to that to reactor thermal and epithermal Neutron Beams. Conclusion In terms of tumor cell-killing effect as a whole, including quiescent cells, accelerated carbon ion Beams, especially with greater LET values, are very useful for suppressing the dependency on the heterogeneity within solid tumors, as well as depositing the radiation dose precisely.
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evaluation of apoptosis and micronucleation induced by reactor Neutron Beams with two different cadmium ratios in total and quiescent cell populations within solid tumors
International Journal of Radiation Oncology Biology Physics, 2001Co-Authors: Shinichiro Masunaga, Yoshinori Sakurai, Koji Ono, Masao Takagaki, Tooru Kobayashi, Yuko Kinashi, Minoru SuzukiAbstract:Abstract Purpose: Response of quiescent (Q) and total tumor cells in solid tumors to reactor Neutron beam irradiation with two different cadmium (Cd) ratios was examined in terms of micronucleus (MN) frequency and apoptosis frequency, using four different tumor cell lines. Methods and Materials: C57BL mice bearing EL4 tumors, C3H/He mice bearing SCC VII or FM3A tumors, and Balb/c mice bearing EMT6/KU tumors received 5-bromo-2′-deoxyuridine (BrdU) continuously for 5 days via implanted mini-osmotic pumps to label all proliferating (P) cells. Thirty min after i.p. injection of sodium borocaptate- 10 B (BSH), or 3 h after oral administration of p -boronophenylalanine- 10 B (BPA), the tumors were irradiated with Neutron Beams. The tumors without 10 B-compound administration were irradiated with Neutron Beams or γ-rays. This Neutron beam irradiation was performed using Neutrons with two different Cd ratios. The tumors were then excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the MN frequency in cells without BrdU labeling (=Q cells) was determined using immunofluorescence staining for BrdU. Meanwhile, for apoptosis assay, 6 h after irradiation, tumor cell suspensions obtained in the same manner were fixed, and the apoptosis frequency in Q cells was also determined with immunofluorescence staining for BrdU. The MN and apoptosis frequencies in total (P + Q) tumor cells were determined from the tumors that were not pretreated with BrdU. Results: Without 10 B-compounds, the sensitivity difference between total and Q cells was reduced by Neutron beam irradiation. Under our particular Neutron beam irradiation condition, relative biological effectiveness (RBE) of Neutrons was larger in Q cells than in total cells, and the RBE values were larger for low Cd-ratio than high Cd-ratio Neutrons. With 10 B-compounds, both frequencies were increased for each cell population, especially for total cells. BPA increased both frequencies for total cells more than BSH did. Nevertheless, the sensitivity of Q cells treated with BPA was lower than that of Q cells treated with BSH. Whether based on the MN frequency or the apoptosis frequency, similar results concerning the sensitivity difference between total and Q cells, the values of RBE, and the enhancement effect by the use of 10 B-compound were obtained. Conclusion: Apoptosis frequency, as well as the MN frequency, can be applied to our method for measuring the Q cell response to reactor Neutron beam irradiation within solid tumor in which the ratio of apoptosis to total cell death is relatively high, as in EL4 tumor. The absolute radiation dose required to achieve the same endpoint for Q cells is much higher than that for total cells when combined with 10 B-compound, especially with BPA.
Minoru Suzuki - One of the best experts on this subject based on the ideXlab platform.
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radiobiologic significance of response of intratumor quiescent cells in vivo to accelerated carbon ion Beams compared with γ rays and reactor Neutron Beams
International Journal of Radiation Oncology Biology Physics, 2008Co-Authors: Shinichiro Masunaga, Koichi Ando, Akiko Uzawa, Ryoichi Hirayama, Yoshiya Furusawa, Sachiko Koike, Yoshinori Sakurai, Kenji Nagata, Minoru Suzuki, Genro KashinoAbstract:Purpose To clarify the radiosensitivity of intratumor quiescent cells in vivo to accelerated carbon ion Beams and reactor Neutron Beams. Methods and Materials Squamous cell carcinoma VII tumor-bearing mice were continuously given 5-bromo-2′-deoxyuridine to label all intratumor proliferating cells. Next, they received accelerated carbon ion or γ-ray high-dose-rate (HDR) or reduced-dose-rate (RDR) irradiation. Other tumor-bearing mice received reactor thermal or epithermal Neutrons with RDR irradiation. Immediately after HDR and RDR irradiation or 12 h after HDR irradiation, the response of quiescent cells was assessed in terms of the micronucleus frequency using immunofluorescence staining for 5-bromo-2′-deoxyuridine. The response of the total (proliferating plus quiescent) tumor cells was determined from the 5-bromo-2′-deoxyuridine nontreated tumors. Results The difference in radiosensitivity between the total and quiescent cell populations after γ-ray irradiation was markedly reduced with reactor Neutron Beams or accelerated carbon ion Beams, especially with a greater linear energy transfer (LET) value. Clearer repair in quiescent cells than in total cells through delayed assay or a decrease in the dose rate with γ-ray irradiation was efficiently inhibited with carbon ion Beams, especially with a greater LET. With RDR irradiation, the radiosensitivity to accelerated carbon ion Beams with a greater LET was almost similar to that to reactor thermal and epithermal Neutron Beams. Conclusion In terms of tumor cell-killing effect as a whole, including quiescent cells, accelerated carbon ion Beams, especially with greater LET values, are very useful for suppressing the dependency on the heterogeneity within solid tumors, as well as depositing the radiation dose precisely.
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evaluation of apoptosis and micronucleation induced by reactor Neutron Beams with two different cadmium ratios in total and quiescent cell populations within solid tumors
International Journal of Radiation Oncology Biology Physics, 2001Co-Authors: Shinichiro Masunaga, Yoshinori Sakurai, Koji Ono, Masao Takagaki, Tooru Kobayashi, Yuko Kinashi, Minoru SuzukiAbstract:Abstract Purpose: Response of quiescent (Q) and total tumor cells in solid tumors to reactor Neutron beam irradiation with two different cadmium (Cd) ratios was examined in terms of micronucleus (MN) frequency and apoptosis frequency, using four different tumor cell lines. Methods and Materials: C57BL mice bearing EL4 tumors, C3H/He mice bearing SCC VII or FM3A tumors, and Balb/c mice bearing EMT6/KU tumors received 5-bromo-2′-deoxyuridine (BrdU) continuously for 5 days via implanted mini-osmotic pumps to label all proliferating (P) cells. Thirty min after i.p. injection of sodium borocaptate- 10 B (BSH), or 3 h after oral administration of p -boronophenylalanine- 10 B (BPA), the tumors were irradiated with Neutron Beams. The tumors without 10 B-compound administration were irradiated with Neutron Beams or γ-rays. This Neutron beam irradiation was performed using Neutrons with two different Cd ratios. The tumors were then excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the MN frequency in cells without BrdU labeling (=Q cells) was determined using immunofluorescence staining for BrdU. Meanwhile, for apoptosis assay, 6 h after irradiation, tumor cell suspensions obtained in the same manner were fixed, and the apoptosis frequency in Q cells was also determined with immunofluorescence staining for BrdU. The MN and apoptosis frequencies in total (P + Q) tumor cells were determined from the tumors that were not pretreated with BrdU. Results: Without 10 B-compounds, the sensitivity difference between total and Q cells was reduced by Neutron beam irradiation. Under our particular Neutron beam irradiation condition, relative biological effectiveness (RBE) of Neutrons was larger in Q cells than in total cells, and the RBE values were larger for low Cd-ratio than high Cd-ratio Neutrons. With 10 B-compounds, both frequencies were increased for each cell population, especially for total cells. BPA increased both frequencies for total cells more than BSH did. Nevertheless, the sensitivity of Q cells treated with BPA was lower than that of Q cells treated with BSH. Whether based on the MN frequency or the apoptosis frequency, similar results concerning the sensitivity difference between total and Q cells, the values of RBE, and the enhancement effect by the use of 10 B-compound were obtained. Conclusion: Apoptosis frequency, as well as the MN frequency, can be applied to our method for measuring the Q cell response to reactor Neutron beam irradiation within solid tumor in which the ratio of apoptosis to total cell death is relatively high, as in EL4 tumor. The absolute radiation dose required to achieve the same endpoint for Q cells is much higher than that for total cells when combined with 10 B-compound, especially with BPA.
Frédéric Saigné - One of the best experts on this subject based on the ideXlab platform.
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A Silicon Diode Based Detector for the Natural Radiative Environment Measurement in Altitude
2012Co-Authors: Denis Pantel, Jean-roch Vaillé, Pierre Chadoutaud, Philippe Cocquerez, Jean-marc Galliere, Frédéric Wrobel, Jean-luc Autran, Luigi Dilillo, Frédéric SaignéAbstract:We report Neutron Beams and stratospheric balloon flights for which we developed a silicon detector. The results from different Neutron Beams are shown to be in good agreement with simulation performed with the MC-ORACLE code. The stratospheric balloon flights used to obtain data on the atmospheric radiation environment shows that experimental results are dependant to the altitude variations.
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a silicon diode based detector for radiation measurement in high altitude natural environment
IEEE-NPSS Real-Time Conference, 2012Co-Authors: Denis Pantel, Jean-roch Vaillé, Pierre Chadoutaud, Philippe Cocquerez, Jean-marc Galliere, Frédéric Wrobel, Jean-luc Autran, Luigi Dilillo, Frédéric SaignéAbstract:We report Neutron Beams and stratospheric balloon flights for which we developed a silicon detector. The results from different Neutron Beams are shown to be in good agreement with simulation performed with the MC-ORACLE code. The stratospheric balloon flights used to obtain data on the atmospheric radiation environment shows that experimental results are dependant to the altitude variations.
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Embedded silicon detector to investigate the natural radiative environment
Journal of Instrumentation, 2012Co-Authors: Denis Pantel, Jean-roch Vaillé, Pierre Chadoutaud, Philippe Cocquerez, Jean-marc Galliere, Frédéric Wrobel, Jean-luc Autran, Luigi Dilillo, Frédéric SaignéAbstract:A detector based on a silicon diode was developed to investigate the natural radiative environment. As the detector is embeddable, it has low power consumption and is lightweight and small. The instrument was tested under different Neutron Beams and used during stratospheric balloon flights. A comparison of the experimental results with Monte Carlo simulation results shows that the embeddable detector is a promising means of investigating the natural radiative environment.
Genro Kashino - One of the best experts on this subject based on the ideXlab platform.
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radiobiologic significance of response of intratumor quiescent cells in vivo to accelerated carbon ion Beams compared with γ rays and reactor Neutron Beams
International Journal of Radiation Oncology Biology Physics, 2008Co-Authors: Shinichiro Masunaga, Koichi Ando, Akiko Uzawa, Ryoichi Hirayama, Yoshiya Furusawa, Sachiko Koike, Yoshinori Sakurai, Kenji Nagata, Minoru Suzuki, Genro KashinoAbstract:Purpose To clarify the radiosensitivity of intratumor quiescent cells in vivo to accelerated carbon ion Beams and reactor Neutron Beams. Methods and Materials Squamous cell carcinoma VII tumor-bearing mice were continuously given 5-bromo-2′-deoxyuridine to label all intratumor proliferating cells. Next, they received accelerated carbon ion or γ-ray high-dose-rate (HDR) or reduced-dose-rate (RDR) irradiation. Other tumor-bearing mice received reactor thermal or epithermal Neutrons with RDR irradiation. Immediately after HDR and RDR irradiation or 12 h after HDR irradiation, the response of quiescent cells was assessed in terms of the micronucleus frequency using immunofluorescence staining for 5-bromo-2′-deoxyuridine. The response of the total (proliferating plus quiescent) tumor cells was determined from the 5-bromo-2′-deoxyuridine nontreated tumors. Results The difference in radiosensitivity between the total and quiescent cell populations after γ-ray irradiation was markedly reduced with reactor Neutron Beams or accelerated carbon ion Beams, especially with a greater linear energy transfer (LET) value. Clearer repair in quiescent cells than in total cells through delayed assay or a decrease in the dose rate with γ-ray irradiation was efficiently inhibited with carbon ion Beams, especially with a greater LET. With RDR irradiation, the radiosensitivity to accelerated carbon ion Beams with a greater LET was almost similar to that to reactor thermal and epithermal Neutron Beams. Conclusion In terms of tumor cell-killing effect as a whole, including quiescent cells, accelerated carbon ion Beams, especially with greater LET values, are very useful for suppressing the dependency on the heterogeneity within solid tumors, as well as depositing the radiation dose precisely.
Yoshinori Sakurai - One of the best experts on this subject based on the ideXlab platform.
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radiobiologic significance of response of intratumor quiescent cells in vivo to accelerated carbon ion Beams compared with γ rays and reactor Neutron Beams
International Journal of Radiation Oncology Biology Physics, 2008Co-Authors: Shinichiro Masunaga, Koichi Ando, Akiko Uzawa, Ryoichi Hirayama, Yoshiya Furusawa, Sachiko Koike, Yoshinori Sakurai, Kenji Nagata, Minoru Suzuki, Genro KashinoAbstract:Purpose To clarify the radiosensitivity of intratumor quiescent cells in vivo to accelerated carbon ion Beams and reactor Neutron Beams. Methods and Materials Squamous cell carcinoma VII tumor-bearing mice were continuously given 5-bromo-2′-deoxyuridine to label all intratumor proliferating cells. Next, they received accelerated carbon ion or γ-ray high-dose-rate (HDR) or reduced-dose-rate (RDR) irradiation. Other tumor-bearing mice received reactor thermal or epithermal Neutrons with RDR irradiation. Immediately after HDR and RDR irradiation or 12 h after HDR irradiation, the response of quiescent cells was assessed in terms of the micronucleus frequency using immunofluorescence staining for 5-bromo-2′-deoxyuridine. The response of the total (proliferating plus quiescent) tumor cells was determined from the 5-bromo-2′-deoxyuridine nontreated tumors. Results The difference in radiosensitivity between the total and quiescent cell populations after γ-ray irradiation was markedly reduced with reactor Neutron Beams or accelerated carbon ion Beams, especially with a greater linear energy transfer (LET) value. Clearer repair in quiescent cells than in total cells through delayed assay or a decrease in the dose rate with γ-ray irradiation was efficiently inhibited with carbon ion Beams, especially with a greater LET. With RDR irradiation, the radiosensitivity to accelerated carbon ion Beams with a greater LET was almost similar to that to reactor thermal and epithermal Neutron Beams. Conclusion In terms of tumor cell-killing effect as a whole, including quiescent cells, accelerated carbon ion Beams, especially with greater LET values, are very useful for suppressing the dependency on the heterogeneity within solid tumors, as well as depositing the radiation dose precisely.
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evaluation of apoptosis and micronucleation induced by reactor Neutron Beams with two different cadmium ratios in total and quiescent cell populations within solid tumors
International Journal of Radiation Oncology Biology Physics, 2001Co-Authors: Shinichiro Masunaga, Yoshinori Sakurai, Koji Ono, Masao Takagaki, Tooru Kobayashi, Yuko Kinashi, Minoru SuzukiAbstract:Abstract Purpose: Response of quiescent (Q) and total tumor cells in solid tumors to reactor Neutron beam irradiation with two different cadmium (Cd) ratios was examined in terms of micronucleus (MN) frequency and apoptosis frequency, using four different tumor cell lines. Methods and Materials: C57BL mice bearing EL4 tumors, C3H/He mice bearing SCC VII or FM3A tumors, and Balb/c mice bearing EMT6/KU tumors received 5-bromo-2′-deoxyuridine (BrdU) continuously for 5 days via implanted mini-osmotic pumps to label all proliferating (P) cells. Thirty min after i.p. injection of sodium borocaptate- 10 B (BSH), or 3 h after oral administration of p -boronophenylalanine- 10 B (BPA), the tumors were irradiated with Neutron Beams. The tumors without 10 B-compound administration were irradiated with Neutron Beams or γ-rays. This Neutron beam irradiation was performed using Neutrons with two different Cd ratios. The tumors were then excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the MN frequency in cells without BrdU labeling (=Q cells) was determined using immunofluorescence staining for BrdU. Meanwhile, for apoptosis assay, 6 h after irradiation, tumor cell suspensions obtained in the same manner were fixed, and the apoptosis frequency in Q cells was also determined with immunofluorescence staining for BrdU. The MN and apoptosis frequencies in total (P + Q) tumor cells were determined from the tumors that were not pretreated with BrdU. Results: Without 10 B-compounds, the sensitivity difference between total and Q cells was reduced by Neutron beam irradiation. Under our particular Neutron beam irradiation condition, relative biological effectiveness (RBE) of Neutrons was larger in Q cells than in total cells, and the RBE values were larger for low Cd-ratio than high Cd-ratio Neutrons. With 10 B-compounds, both frequencies were increased for each cell population, especially for total cells. BPA increased both frequencies for total cells more than BSH did. Nevertheless, the sensitivity of Q cells treated with BPA was lower than that of Q cells treated with BSH. Whether based on the MN frequency or the apoptosis frequency, similar results concerning the sensitivity difference between total and Q cells, the values of RBE, and the enhancement effect by the use of 10 B-compound were obtained. Conclusion: Apoptosis frequency, as well as the MN frequency, can be applied to our method for measuring the Q cell response to reactor Neutron beam irradiation within solid tumor in which the ratio of apoptosis to total cell death is relatively high, as in EL4 tumor. The absolute radiation dose required to achieve the same endpoint for Q cells is much higher than that for total cells when combined with 10 B-compound, especially with BPA.