Oxygen radicals--biochemical basis for their efficacy.

In the last decade it has become quite clear that oxygen free radicals are involved in a vast amount of diseases such as cataract, atherosclerosis, rheumatism, arthritis, Parkinson's disease, reperfusion injuries and many others. The induction of defence systems against certain stresses (heat shock, inflammation) is also mediated by activated oxygen species. Oxygen-activation and -desactivation has to be regulated and well attenuated in aerobic cells and tissues. The biochemical basis of the biological efficacy of oxidants is thus based on a sophisticated balance between catalysis of production and reactivity of oxygen radicals by certain cofactors and transition metals on the one hand and on a reliable detoxification by antioxidants or metabolic chains on the other hand. In this communication, different oxygen activating principles are compared and the biochemical basis for the induction of repair processes by a synthetic heme oxidant, (Tetrachlorodecaoxide, TCDO) is presented.