| Project/Area Number |
17510056
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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 |
Risk sciences of radiation/Chemicals
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| Research Institution | National Institute of Radiological Sciences |
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Principal Investigator |
REIKO Kanda National Institute of Radiological Sciences, Regulatory Sciences Research Group, Research Center for Radiation Protection, Team leader (40250120)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥2,550,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥150,000)
Fiscal Year 2007: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥900,000 (Direct Cost: ¥900,000)
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| Keywords | Radiation / Chromosome |
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| Research Abstract |
The aim of this study is to find detectable cytogenetic biomarkers that can offer information about the radiation quality of in vivo exposure retrospectively. Chromosome-type aberrations of peripheral lymphocytes of uterine cancer patients that received internal gamma-and external X-ray therapy or carbon beam therapy and of victims severely exposed to neutrons and gamma-rays in a criticality accident that occurred in Tokai-mura, Japan were analyzed. Data obtained from in vitro irradiated experiments using 60Co gamma-rays and 10 MeV neutrons were compared with the in vivo exposed data. As a result, the ratio of acentric rings to dicentric chromosomes (termed RaD ratio) and that of excess fragments to dicentrics (termed EfD ratio) showed significant differences between the two groups of cancer patients, and these ratios for accidental victims were in between the values of the two groups of cancer patients. The in vitro studies using doses equivalent to 1-3 Gy of gamma-rays have confirmed that the EfD ratios were increased with the high LET (linear energy transfer) and RaD ratios decreased. The present data show that the RaD and EfD ratios can be used as cytogenetic biomarkers of exposure to high-LET radiation at least within a few years of exposure. The RaD and EfD ratios were, examined their validity as cytogenetic biomarkers using the sample of the residents in the high background radiation area (HBRA) of Ramsar, Iran.
An improved culture system of mouse peripheral blood lymphocytes for analysis of radiation-induced chromosome aberrations and chemically induced PCC techniques in short-term cultured human peripheral lymphocytes were developed, which were necessary to investigate the mechanisms that RaD and EfD ratios are dependent on LET.
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