The effect of therapeutic ultrasound on calcium uptake in fibroblasts.

The effect of therapeutic ultrasound on calcium uptake by embryonic chick 3T3 fibroblasts has been studied using calcium-45 radiotracer techniques. Cells were treated while suspended in culture medium at 36 degrees C at intensities from 0.25 W/cm2 SPPA to 1.5 W/cm2 SPPA (1 MHz, pulsed 2 ms on:8 ms off) and for exposure times from 1 min to 20 min. Ultrasound treatment was found to increase calcium uptake for SPPA intensities from 0.5 to 1.0 W/cm2 SPPA, with a maximum increase of 18% after a 5 min exposure. Calcium uptake also increased with increasing exposure time. Measurements performed up to 20 min after treatment showed that the cell was able to reduce this calcium influx, indicating that the membrane did not suffer irreparable damage as a result of the ultrasound exposure.