2003 Fiscal Year Final Research Report Summary
Radionuclide imaging of apoptosis in irradiated tumors
| Project/Area Number |
14570840
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Radiation science
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
MURATA Yuji Tokyo Medical and Dental University, University Hospital Faculty of Medicine, Lecturer, 医学部附属病院, 講師 (10239535)
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| Co-Investigator(Kenkyū-buntansha) |
MIURA Masahiko Tokyo Medical and Dental University, Graduate School, Associate Professor, 大学院・医歯学総合研究科, 助教授 (10272600)
SHIBUYA Hitoshi Tokyo Medical and Dental University, Graduate School, Professor, 大学院・医歯学総合研究科, 教授 (10014292)
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| Project Period (FY) |
2002 – 2003
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| Keywords | annevin V / apoptosis / radionuclide imaging / radiation |
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| Research Abstract |
The purpose of this study was to develop a non-invasive imaging technique to measure and monitor apoptosis in tumor cells caused by irradiation, using 125I radiolabeled Annexin V.
The tumors used were human ependymoblastomas that were transplanted into nude mice. The tumors were irradiated at 2,5 or 10 Gy. ^<125>I-annexinV was administered intravenously 6 hours after the irradiation. In the 5-Gy irradiation group, the isotope was injected after various time-intervals (3,6 and 12 hours) from the irradiation. Three hours after the injection, the mice were sacrificed and the tumors quickly removed, and frozen sections were prepared at 6- to 40-μm thickness using a cryomicrotome. In autoradiography imaging, the tumor-to-muscle ratios were compared in the respective irradiated groups. In addition, apoptosis detection by the ISEL (Klenow) assay was couducted on the same sections. The number of Klenow-positive cells was counted in x100 fields for each section.
Both autoradiography and immunohistochemical staining showed a significantly higher frequency of apoptosis in the neoplasm in all the irradiated groups as compared with that in the control group (p<0.05). Although immunohistochemical staining revealed the peak apoptosis frequency in the 5-Gy-irradiated group, autoradiography revealed the peak in the group receiving a lower dose than 5 Gy. When time from irradiation to Annexin injection was changed, both imaging showed the peak apoptosis frequency in the group receiving the injection 6 hours after the irradiation.
The possibility of noninvasive prediction of the treatment effect in cases of cancer by apoptosis imaging in vivo after radiotherapy was shown in this study.
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Research Products
(2 results)
