| Co-Investigator(Kenkyū-buntansha) |
FUCHIKAWA Yuuichi Shiga University of Medical Science, Faculty of Medicine, Research Associate, 医学部, 助手 (00093170)
SATO Hiroshi Shiga University of Medical Science, Faculty of Medicine, Associate Prof., 医学部, 助教授 (90090430)
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| Budget Amount *help |
¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 1995: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1994: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1993: ¥3,500,000 (Direct Cost: ¥3,500,000)
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| Research Abstract |
Biological effect of ultrasound (1 MHz, less than 5 W-cm^2) was studied. In this project, we clsssified the effects into two groups. One is the effect which is confined in the insonated individuals ; developmental and teratogenic effect, the other is the effect which is persisting to successive generations ; genetic effet. We studied on the first one. The biological effects induced by X-ray irradiation were always used as a positive control. We deviced a new experimental system to analize the effects of ultrasound quantitatively and qualitatively. Waterflea (Moina macrocopa) , hydra (Hydra magnipappilata) and cultured mammallian cells (L5178Y,L5178Y-M10) were used. Experimental items were cell survival, G_2 block and effect on cellular components for cells, survival days, breeding time/life cycle, number of imago produced/life cycle, litter size and effect on the formation on complex eye for waterflea, and budding rate, survival, number of tentacles of newly detached hydra for hydra.
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sults obtained were as follws ; (1) The effect of ultrasound was occured during and immediately after insonation. The death of waterflea was occurred by very weak intensity of ultrasound (even 0.5 W/cm^2,10 sec.). similar effect was observed in cultured cells and hydra. (2) The individuals escaped from the death by insonation were used for each experiment. They were separately kept in individual well through the experiment. All the data obtained from survived individuals were not different from the one from negative control group. Delayd effect as seen in X-irradiated group was not observed. (3) Damage on the complex eyes was observed when waterflea were treated with X-ray or ultrasound at the time which eye anlarge develops in embryo. Waterflea has 22 ommatidia per complex eye. When X-ray was irradiated, the number of ommatidia was decreased and anomaly of the lens was observed. However, when ultrasound was insonated, only anomaly of ammatidia lens was observed. (4) Free radical induced by insonation are considered to induce the biological effect. To confirm this speculation, we used the same procedure for the experiment on radiation protection. We used mercaptoethanolamine (MEA) as a radical scavenger. The effect induced by the insonation was not protected at all by radical scavernger. (5) We confirmed the enhancing (hormetic) effect due to small amount of ultrasound. The interval of breeding of moina and the budding rate of hydra was shortened and enhanced. The mechanism of hormetic effects are under survey with relation to cell proliferation. Less
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