MECHANISMS OF TISSUE-INJURY BY OXYGEN RADICALS - IMPLICATIONS FOR NEONATAL DISEASE

A role of the oxygen radical generating system hypoxanthine-xanthine o xidase in hypoxia-reoxygenation injury was proposed 15 years ago. In r ecent years, however, new understanding of hypoxia-reoxygenation injur y has been achieved and the significance of other oxygen radical gener ating systems has been acknowledged too. The hypothesis that an oxygen radical disease exists in preterm infants has recently been strengthe ned; an important observation is that preterm infants have lower activ ities of erythrocyte Cu/Zn superoxide dismutase compared to term babie s. New actions of oxygen radicals have also been emphasized, and recen tly it has been demonstrated that the degree of protein oxidation of t he lung of newborn infants is associated with chronic lung injury. The new insight into the interaction of oxygen radicals with other system s as excitatory amino acids and the NO system also increases the possi bility to understand and hence prevent oxygen radical injury in the pr eterm infant as well as in adults exposed to an increased load of oxyg en radicals.