| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2014: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2013: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2012: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Outline of Final Research Achievements |
The available data on the carcinogenic mechanisms of neutron exposure in children are still limited. We examined the effects of neutron irradiation using Ptch1 heterozygous mice, which are prone to spontaneous and radiogenic medulloblastoma (MB), comparing with the effects of gamma-rays.
We found that the effects of gamma-rays and neutron radiation on MB induction were dependent on the age at exposure. The MB incidence was significantly higher for neutron irradiation compared with gamma-irradiation during the prenatal and early postnatal period. Irradiation with either gamma-rays or neutrons at postnatal day 10 resulted in MB incidence lower than spontaneous MB. These results indicate opposing effects of radiation, clearly inducing MB during the prenatal and early postnatal periods while seemingly suppressing MB below the spontaneous levels in these sensitive mutant mice. Neutrons appear to be more effective than gamma rays at the same for both inducing and suppressing MB.
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