| Budget Amount *help |
¥5,590,000 (Direct Cost: ¥4,300,000、Indirect Cost: ¥1,290,000)
Fiscal Year 2014: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2013: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2012: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Outline of Final Research Achievements |
Little is still known about mutagenic effect in fetal animals of fission neutrons. The present study was conducted in which fetal mice heterozygous at the Dlb-1 locus were irradiated at the organogenic stage with fission neutrons, X-rays at a high dose rate or gamma-rays at a low dose rate. Teratogenic and clastogenic effects of these radiations in fetal ICR mice were also investigated. Irrespective of the kind of endpoints used, fission neutrons were the most effective, followed by X-rays and gamma-rays in this sequence. Induced rates of mutations by fission neutrons determined at two time points during the organogenic stage do not differ significantly from each other. The same was true for the induction by other radiations. These results suggest fairly uniform sensitivity of fetal somatic cells to ionizing radiation for mutation induction during the organogenic stage in contrast to a marked shift in X-ray sensitivity seen for the induction of malformation.
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