Lack of effect of continuous wave ultrasound exposure on in vivo Chinese hamster cheek pouch epithelial mitotic index.

Chinese hamster cheek pouches were everted and the epithelia exposed in vivo for 1 min to continuous wave 1.07 MHz ultrasound at intensities ranging from 0.5 to 10.0 W cm-2. Since the mitotic index of the hamster epithelium exhibited a circadian rhythm, the times of sonication and tissue sampling were arranged to allow for detection of a division delay as evidenced by a change in mitotic index in cells insonated in the early S or late S/early G2 phases of the cell cycle. There was no demonstrated effect of the ultrasound exposures on mitotic index.