HIGH PLASMA VITAMIN-C CONCENTRATIONS AT BIRTH ASSOCIATED WITH LOW ANTIOXIDANT STATUS AND POOR OUTCOME IN PREMATURE-INFANTS

Concentrations of circulating antioxidants may be important in the aet iology of disease in premature infants. Blood samples were taken from 49 premature infants within two hours of birth. Plasma ascorbic acid, caeruloplasmin, and the ability of plasma to prevent lipid peroxidatio n in vitro were measured. Plasma ascorbic acid concentrations at birth ranged from 26.3 to 185.4 mu mol/l. Plasma antioxidant activity at bi rth (mu l plasma required to inhibit lipid peroxidation) showed a stro ng negative correlation with plasma ascorbic acid and the plasma ascor bic acid to caeruloplasmin ratio. After correcting for,gestational age and birth weight, plasma antioxidant activity at birth remained a sig nificant predictor of mortality. Such plasma antioxidant activity is p artly determined by the ferroxidase activity of caeruloplasmin. This m ay be modulated by high concentrations of ascorbic acid which may inhi bit the antioxidant activity of plasma and thereby influence outcome.