ABSTRACT
Objective To observe changes of the ultrastructure and the cell cycle of hepatoma cells exposed to ultrasound-mediated disruption. Methods Suspensions of Walker-256 hepatoma in vitro exposed to ultrasound disruption with the acoustic power output 0 22 W and the ultrasound frequency 42 kHz were observed by the scanning electron microscopy, the transmission electron microscopy and the flow cytometric analysis of DNA content. Results Cells after ultrasound disruption revealed by scanning electron microscopy exhibited ruptured membrance, disordered organellae and disrupted nucleus, showing typical severe destruction of the cells. Flow cytometric analysis of DNA content demonstrated an increased in the population of cells in the G 2 and M phases of the cell cycle but a decrease in number of cells in the S phase, suggesting an inhibition of the cell synthese and an increased sensitivity to radiation. Conclusions Ultrasound disruption can destroy tumor cells effectively at the cellular level.