[Effects of ultrasonic irradiation on chromosomes, cell division and developing embryos (author's transl)]

These experiments were planned to acquire any informations about the possibilities of harmful effects of ultrasonics on the chromosomes, the cell division of cultured cells and the developing embryos of the ICR mice. 1. The effects of ultrasonics on the chromosomes. Lymphocytes of fetal blood, fibroblasts of fetal skin and fibroblasts from amniotic fluid were exposed to the continuous ultrasonics of 2MHz with the intensity of 2W/cm2, 1 hour. No significant increase of chromosomal aberrations was found in the exposed groups. 2. The effects on the growth of cultured cells. Fibroblasts of fetal skin were exposed to the continuous ultrasonics of 2MHz (max 2MHz, 2 hours). The cell growth was observed during 14 days, but no suppression on the cell division appeared in the exposed groups. 3. The effects on the ICR pregnant mice. In total, 125 ICR pregnant mice were exposed to the ultrasonics of 2MHz on 8th day of pregnancy (I; control group, II; buffered control group, III; 200 mw/cm2 and IV; 2000 mw/cm2, 5 min). The weight gain of maternal body was suppressed in group IV. The number of implantation sites in group IV was significantly higher than the other 3 groups. The external, skeletal and visceral abnormalities were examined for 1251 fetuses. Brain hernia, anencephaly, cleft palate and skeletal abnormalities were found in group IV and its incidence was significantly higher than the other 3 groups.