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Research into the effects of radiation delivered at ultrahigh dose rates > 1 × 107 Gy/min to biological objects is a new promising area of radiobiology. The unique characteristics of the high-current nanosecond electron accelerator Mir-M enable its use in medical and biological research, specifically in the experiments aimed at investigating the effect of therapeutic doses at a dose rate up to 100 MGy/s. In this work we study the effects of ultrahigh dose rate photon radiation on human lung carcinoma (A549) and melanoma (MelMtp-x) cells lines and compare them with those of the therapeutic gamma unit Rokus-AM. We show that ultrahigh dose rates induce more significant damage in the studied cell lines at doses between 2 and 7 Gy, radioresistant melanoma being more sensitive to photon radiation delivered at ultrahigh dose rates.

Activity of ATPase in functional element of myocardium (its qualitative and quantitative aspects) has been researched in normal tissue and in one with various levels of hypothermic ischemia (28-30 degrees C and 10-12 degrees C) by methods of electron microscopic histochemistry on dogs. It has been found that hypothermia of myocardium (10-12 degrees C) optimally prevents ischemic disorders of energetic processes. Reproduction activity of ATPase during reperfusion of myocardium after that hypothermia maintains contractile function of heart in proper high level.