Combined action of ultrasound and ionizing radiation on yeast cells

Abstract

This communication reports the observation of synergistic relationships between ultrasound and gamma-irradiation of stationary phase cultures of Saccharomyces cerevisiae of different strains. The gamma-ray dose was applied before or after the sound. The extent of synergism depended upon the sequence of application; it was smaller for (US + gamma-ray)-exposure in comparison with gamma-ray +US)-treatment. The combined action of both modalities had smaller or no synergistic effect for mutant(rad51) yeast cells incapable of recovery. On this basis, it was concluded that possible mechanisms for ultrasound radiosensitization of yeast cells may involve the reduced capacity of cells to recover damages resulted from the combined action and/or the enhanced expression of lethal damage.

MR-guided focused ultrasound surgery, present and future

“…42,43 r Radiosensitization: High-intensity ultrasound at subablation temperatures can generate hyperthermia which causes radiosensitization or chemosensitization of targeted tissue. 44,45 This effect could play an important role in combination FUS/radiation therapies. 46 r Soft tissue erosion (histotripsy): Short, high-intensity pulses of ultrasound can achieve mechanical erosion of soft tissues, especially at tissue/fluid interfaces.…”

“…131 Alternatively, FUS could be used as a salvage treatment after local failure with radiation, with one study reporting a 71% disease-free rate after whole gland ablation of the prostate after localized recurrence post-external-beam radiotherapy. 129 It has been known for some time that heat can be a potent radiosensitizer, 44,45 likely because heat insult prevents the cells from efficiently repairing sublethal DNA damage from radiation. 183 Hypoxic tissues do not show the same resistance to thermal insult as they do to ionizing radiation.…”