Using the HPLC methodology, we measured uMDA in 19 preterm infants, with birth weights of 1384 +/- 533 g, GA 30.2 +/- 3.6 weeks, and time of sample collection ranging from 12 to 240 hours. We recorded information on oxygen support, serum bilirubin levels, and clinical disorders related to free radical mechanisms (ORD)including sepsis, intraventricular hemorrhage, retinopathy of prematurity, and bronchoppulmonary dysplasia.

For the population, the uMDA levels were 33.5 +/- 21.4 ng/mg creatinine. Oxygen therapy was associated with increased levels of uMDA (r=.415), and correlated with uMDA and rate of uMDA rise (p<0.05). Serum bilirubin concentration on the second day of life and maximum levels achieved during the first week were inversely related to urine MDA-TBA levels.

Six infants suffering from ORD were lighter (979 +/- 604g vs. 1571 +/- 394g) and less mature (26.5 +/- 3.3wks vs. 31.9 +/- 2.3 wks) than the 13 controls. The rates of uMDA were +0.544 and -0.027 ng/mg creatinine/hr in ORD and non-ORD infants. Similarly maximum levels of uMDA were 54.8 +/- 27.4 vs. 32.9 +/- 20.1 ng/mg creatinine in the two groups (p<0.05). These results suggest that ROS play a key role in the generation of these disorders.