| Project/Area Number |
62570783
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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 |
Otorhinolaryngology
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| Research Institution | Jichi Medical School |
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Principal Investigator |
HIRAIDE Fumihisa Assistant Professor, Faculty of Medicine, Jichi Medical School, 医学部, 助教授 (50010343)
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| Co-Investigator(Kenkyū-buntansha) |
KAKOI Hiroyuki Assistant, Faculty of Medicine, Jichi Medical School, 医学部, 助手 (40201412)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1988: ¥100,000 (Direct Cost: ¥100,000)
Fiscal Year 1987: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | Rat / infrasound exposure / 2 years / scanning electron microscopic observation / outer hair cells / inner hair cells / degeneration / 形態的変化 / 低周波音暴露 / 2年間 / 走査電顕的観察 / 外有毛細胞 / 内有毛細胞 / 変性消失 / 老化現象 / 光顕的観察 / 蝸牛ラケン器 |
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| Research Abstract |
One hundred and three rats of Wistar strain were used in this study. Sixty-nine rats were received infrasound of 0-125 Hz at 85 dB (allpass) for two years and thirty-four animals were offered as controls. The animals exposed in infrasound were periodically sacrificed at two months' interval up to the termination of two years' exposure. The cochleas were examined by means of a scanning electron microscope. The hair cells of the organ of Corti showed an absolutely normal histolohgy in the animals exposed in infrasound of one year's duration. However, the loss of outer hair cells was always noted sporadically in the cochlea of the animals exposed in infrasound of 1.5 years' duration.
The animals in infrasound of 2 years' exposure showed a decreased number of the outer hair cells in the organ of Corti of the upper turns, especially apical turn. The pattern of the hair cell loss in the organ of Corti of experimented animals was almost similar to that of controlled animals. Accordingly, the authors considered that the loss of the hair cells in the organ of Corti was due to age-related changes in both experimented and controlled animals.
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