Methods for Measurements of Increased Release of Free Oxygen Radicals

The biological efficacy of oxidants is based on a highly regulated equilibrium between the production of oxygen radicals and the counteracting defense mechanisms of antioxidant scavenging systems and repair enzymes for the elimination of the degraded bioproducts. Imbalance of this finely tuned, sophisticated equilibrium can result in oxidative stress unleashing a cascade of pathological processes. This review summarizes the general aspects of the analytical methods used for the detection of an excess of free radicals together with a critical evaluation of the results obtained by their application. Free radicals are very reactive, short-lived and react in a non-specific way. In spite of the broad array of existing analytical methods no routine diagnostic in vivo procedures are available to date. The development of more site-specific in vivo methods will enable the elucidation of the exact role of these very reactive radicals and molecular species. For the time being, the most important task of physicians and surgeons is to prevent all catalytic reactions known to initiate pro-oxidative stress and counteract the absolute or relative lack of antioxidants.