Modification of ultrasound induced changes in mammalian cells by increased viscosity of medium and increased ambient pressure.

Abstract

Ehrlich ascites tumour cells (E.A.T.) in suspension were exposed to ultrasound of frequency 1x5 MHZ, intensities 1x4, 2x8 W/cm2 for 60 min at 37 degrees C. The suspensions of E.A.T. cells were contained in Perspex vessels with Melinex windows, situated in the near field of a piezoceramic transducer. Subsequently the rate of net influx of Rb-86 ions was studied over a period of 90 min. A reduced Rb-86 activity of insonated cell populations was observed compared to controls. Similar experiments were carried out involving E.A.T. cells suspended in isotonic medium containing 0x25 per cent agar (2x1 centipoise). No significant depression of uptake of Rb-86 ions was observed at 2x8 W/cm2, 1x5 MHZ. Cells insonated in normal medium at 1x9 atmos. helium pressure subsequently showed no depression of Rb-86 uptake, compared to controls, following insonation at 2x8 W/cm2, 1x5 MHZ for 60 min.