1992 Fiscal Year Final Research Report Summary
Studies of mechanisms underlying tumor hypoxia
| Project/Area Number |
02807105
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Radiation science
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| Research Institution | National Institute of Radiological Sciences |
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Principal Investigator |
ANDO Koichi NIRS, Div.Clin.Res., Section head, 臨床研究部, 室長 (00159526)
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| Co-Investigator(Kenkyū-buntansha) |
KOIKE Sachiko NIRS, Div.Clin.Res., Senior researcher, 臨床研究部, 主任研究官 (50161831)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Hypoxic fraction / Intermediate hypoxia / Misonidazole / MRI / Perfusion mismatch / Blood flow / Blood volume |
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| Research Abstract |
Pathogenesis of tumor hypoxia was investigated for two murine fibrosarcomas transplanted into syngeneic C3H mice. Results obtained here were as follows. (1)R1137 fibrosarcomas with 7mm in diameter gave a single phase of cell survival curve with a Do of 1.3Gy when tumors were irradiated in vivo with Cs-137 gammarays. No hypoxic fraction was detected by lung colony assay. An i.p.-administration of Misonidazole failed to sensitize the tumor. Large-sized R1137 tumors showed again a single phase of cell survival curve, but gave a large Do value of 2.6Gy. Successful sensitization by misonidazole indicated that the large-sized R1137 tumors were under intermediate hypoxia. (2)Tumor blood flow and blood volume were measured by a method of Gd-DTPA enhanced nuclear magnetic resonance imaging(MRI). When dynamic change of T1 values for proton in tumors was analyzed by a compartment model, tumors with intermediate hypoxia showed a lower ratio of blood flow to blood volume than tumors with fractional hypoxia. (3)Tumors with intermediate hypoxia showed 30% perfusion mismatch in the blood vessels when Hoechst 33342 and DioC_7(3) were sequentially injected into mice bearing large R1137 tumors.
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