Sister chromatid exchanges in laboratory cultured cells after repeated exposures to pulsed ultrasound.

In this in vitro study, suspensions of DON cells (lung diploid cell line from the Chinese hamster) were exposed to ultrasound regimes using pulse lengths similar to those used in ultrasonic Doppler measurements of fetal blood flow. The base level frequency of sister chromatid exchanges (SCE) was not significantly altered following exposure to a range of spatial peak temporal average intensities from 0.1 to 4.0 W/cm2. Repeating the exposure on three further occasions during the 20 generations following the initial insonation also had no effect. When DON cells were incubated in the presence of Mitomycin C (MCC), a positive dose-related increase in SCE frequency was observed, indicating the sensitivity of these cells to in vitro SCE induction. Coincidental exposure to ultrasound and Mitomycin C did not increase the SCE level above that obtained with MCC alone, and it was concluded that there was no evidence of a synergistic association.