Molecular damage to membrane proteins induced by ultrasound.

A dilute suspension of human erythrocytes was exposed in vitro to ultrasound (US) with a frequency of 1 MHz and an acoustic pressure of (3.0 +/- 0.4) x 10(5) Pa (intensity of 2.9 +/- 0.8 W/cm(2)). The degree of lysis of the cells in saline increased with increasing the exposure time. An addition of a small amount of plasma to the suspension did not change the degree of lysis. A gel electrophoresis of membrane proteins extracted from the exposed and lysed membrane samples showed that the exposure caused molecular damage in membrane proteins in the absence of plasma, and that the addition of the small amount of plasma protected the proteins against the molecular damage.