Stable cavitation at low ultrasonic intensities induces cell death and inhibits 3H-TdR incorporation by Con-A-stimulated murine lymphocytes in vitro.

Murine spleen cell suspensions stimulated by Concanavalin A (Con-A) were exposed to 1.6-MHz continuous-wave ultrasound at low intensities (spatial-peak values ranging from 16 to 300 mW/cm2) in the presence of a Nuclepore membrane that contained stabilized gas bodies. The ultrasonically activated gas bodies induced cell lysis and reduced the fraction of intact cells that excluded trypan blue. At a spatial-peak intensity of 75 mW/cm2 (spatial-average intensity 15 mW/cm2), Con-A-induced Methyl[3H]thymidine (3H-TdR) incorporation was reduced in cultures exposed at 24 or 48 hr after addition of Con-A but not at 7 or 13 hr. There was no observable effect on cell survival or 3H-TdR incorporation at spatial-peak intensities below 75 mW/cm2.