OXIDATION-PRODUCTS OF URIC-ACID AND ASCORBIC-ACID IN PRETERM INFANTS WITH CHRONIC LUNG-DISEASE

Allantoin, the oxidation product of uric acid (UA), can be used as an in vivo marker of free radical generation, The aims of the present stu dy were to evaluate the allantoin changes in plasma and bronchoalveola r lavage fluid (BALF) as well as to examine plasma levels of ascorbic acid (AA) and its oxidation product, dehydroascorbic acid (DHAA), in i nfants with or without chronic lung disease (CLD) during the first wee k of life, The study population was 20 infants of 24-30 weeks gestatio n, comprising 10 who subsequently developed CLD and 10 without CLD. In the CLD infants, the plasma allantoin/UA ratio showed a significant i ncrease after day 1 and continued to increase gradually to reach a pea k on day 6 (6.5 +/- 4.1% for CLD and 2.1 +/- 0.9% for non-CLD infants) . The allantoin/UA ratio in BALF was also higher in CLD infants and th e difference reached significance on days 4-6 (41.2 +/- 15.8% for CLD and 11.7 +/- 9.9% for non-CLD infants). In contrast to allantoin, the plasma DHAA/AA ratio did not differ between the 2 groups throughout th e study period. Our findings that the allantoin/UA ratios were signifi cantly higher in CLD than non-CLD infants not only in plasma but also in BALF, and that the intergroup differences of this ratio in both pla sma and BALF was more prominent in the latter half of the first week o f life further confirm our previous speculation that oxygen radicals a re involved in the development of neonatal CLD.