Quantitative relationships between ultrasonic cavitation and effects upon amoebae at 1 MHz.

An •mo•b•, Hartmanindia •astdlanii, which possesses many features typical of higher-order animal cells, was irradiated with 1-MHz ultrasound while suspended inordinary growth medium and in one with increased viscosity. The ultrasonically produced cavitation was monitored and a strong correlation is found between the number of discrete cavitation events occurring and the decrease in cell number% on irradiating at 515 W/cm • for 10 min. The growth of treated cells was also examined.