FREE-RADICALS IN HEALTH AND DISEASE

The biological efficacy of oxidants is based on a highly regulated equ ilibrium between the production of oxygen radicals and the counteracti ng defense mechanisms of antioxidant scavenging systems and repair enz ymes for the elimination of the degraded bioproducts. Imbalance of thi s finely tuned, sophisticated equilibrium can result in oxidative stre ss unleashing a cascade of pathological processes. This review summari zes the general characteristics of oxidative reactions and gives examp les of some groups of diseases in which free radicals and reactive oxy gen species (ROS) are thought to play a pivotal role. General aspects of the analytical methods used for the detection of an excess of free radicals are discussed together with a critical evaluation of the resu lts obtained by their application. Free radicals are very reactive, sh ortlived and react in non-specific way. In spite of the broad array of existing analytical methods no routine diagnostic in vivo procedures are available to date. The results of fundamental research and clinica l investigations have none-the-less focused the attention to the proba bly crucial role of free radicals in aging and in the pathogenesis of many human diseases. The development of more site-specific in viva met hods will enable the elucidation of the exact role of these very react ive radicals and molecular species. For the time being, the most impor tant task of physicians and surgeons is to prevent all catalytic react ions known to initiate pro-oxidative stress and counteract the absolut e or relative lack of antioxidants.