KONDO Hisayoshi Nagasaki Univ.School of Medicine, Assistant, 医学部, 助手 (00170431)
SAKAE Mihoko Nagasaki Univ.School of Medicine, Assistant, 医学部, 助手 (70244051)
ISEKI Masachika Nagasaki Univ.School of Medicine, Assistant, 医学部, 助手 (50176252)
|Budget Amount *help
¥1,800,000 (Direct Cost : ¥1,800,000)
Fiscal Year 1993 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1992 : ¥1,300,000 (Direct Cost : ¥1,300,000)
Although changes in the walls of cerebral blood vessels have been reported, almost no research has been conducted to date on the relationship between radiation injuries and senile dementia, including cerebrovascular dementia, as aging-related changes. In view of this situation, we investigated cerebral dysfunctions resulting from irradiation and conducted basic research on their morphological and epidemiological characteristics.
1.The brain tissues of atomic bomb survivors and non-exposed persons were studied histologically and immunohistologically, with special attention to senile plaques, neurofibrillary tangles and other aging-related morphological changes that might indicate an increase in changes due to atomic bomb exposure. However, the resulting data did not support the hypothesis that aging-related cerebral changes are more frequent in atomic bomb victims than in non-exposed persons.
2.The morphological effects of irradiation were studied both light-and electron-microscopically u
sing mice. Although certain morphological changes were noted in the capillary endothelium and the walls of the cerebral blood vessels, these changes were not considered severe enough to constitute a clear difference in cerebral dysfunction between the exposed and non-exposed groups.
3.An epidemiological study was conducted on senile dementia among residents of Nagasaki City, which has a large number of atomic bomb survivors, and the Yangjiang area of Guangdong Province, China, which is known as an area with high background radiation. The results showed that the prevalence of senile dementia was no higher in Nagasaki or Yangjiang than in other areas of Japan or the world.
In other words, our studies revealed that, whether it is a large single dose or a low dose over a long period of time, there is virtually no cause and effect relationship between radiation exposure and senile dementia.