الفهرس 
PREMATURITYOnly 14 pages are availabe for public view
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Abstract
Background: Preterm neonates with respiratory distress syndrome are at high risk of oxidative stress and they are very susceptible to free radical oxidative damage. In nuclear and mitochondrial DNA, 8-hydroxy-2’ -deoxyguanosine (8-OHdG) is one of the predominant forms of free radical-induced oxidative lesions, and has therefore been widely used as a biomarker for oxidative stress. Aim: To assess oxidant-antioxidant balance in preterm neonates with RDS as well as the role of lipid peroxidation and oxidative DNA damage in the development of neonatal RDS. Methods: the study included 80 preterm neonates less than 34 weeks of gestational age; 40 had RDS and 40 without RDS enrolled as controls. All newborns were subjected to detailed medical history, thorough clinical examination. The degree of respiratory distress was assessed according to Down score. Respiratory distress grade was determined according to chest X ray. Laboratory investigations included complete blood count, random blood sugar, arterial blood gases, total antioxidant capacity (TAC), malondialdehyde (MDA) as an index of lipid peroxiadation, 8-OHdG levels by ELISA and trace elements (copper, zinc, calcium, magnesium and iron). Results: Neonates with RDS had lower birth weight and gestational age in comparison to control group. There was no significant difference in maternal age, parity, mode of delivery, PROM, maternal disease and steroid intake between mothers of neonates with RDS and control group. TAC, MDA and 8-OHdG were significantly high compared with control group. No significant difference was found as regard trace elements (zinc, calcium, magnesium, iron) except for copper which was significantly lower in neonates with RDS. TAC was significantly lower among neonates with RDS at day 3 compared with day 1 while MDA and AOPPs, 8-OHdG were significantly higher at day 3. 8-OHdG levels at day 1 and day 3 were significantly higher in neonates in RD grade 4 compared with those in grades 2 or 3 and among patients on mechanical ventilation as well as those with positive CRP values. 8-OHdG levels at day 3 were also significant in relation to mortality. 8-OHdG levels at days 1 and 3 are negatively correlated to gestational age, birth weight, OFC and PH. There was significant positive correlation with each of maternal age, duration of ventilation and duration of hospitalization as well as MDA and CO2. Multivariable regression model showed that maternal age, gestational age, birth weight, OFC, duration of ventilation, duration of hospitalization and MDA were the significant independent variables related to elevated 8-OHdG levels at day 1 and 3. Conclusions: Oxidative stress is induced in neonates with RDS which is manifested as increased lipid peroxidation and oxidative DNA damage. This is accompanied by alterations in the antioxidant defense status which may also play a role in the pathogenesis of RDS. AOPPs could be considered a reliable novel marker for oxidative stress among neonates with RDS. It is necessary to limiting exposure of the preterm infants to oxygen at high percentage and to high positive pressure during resuscitation and subsequent ventilation.