الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Summary
Hyperbilirubinemia is one of the important problems encountered in neonatal units which is clinical observed in 60% of full-term and 80% of preterm infants. Free radicals damage has been recognized as a common pathogenic mechanism of many neonatal diseases. It may be evolved after hyperoxia or post-ischemic reperfusion.
Cells normally respond to oxidative stress by up grading of the antioxidant defenses including antioxidant enzymes, antioxidant vitamins, and other protective systems. But over production of free radicals damages proteins, lipids and DNA and leads to cell transformations or cell death.
Phototherapy ( the first and the main step in management of neonatal hyperbillirubinemia) has an oxidative effect on newborn causing lipid peroxidation of RBCS membrane.
Lipid peroxidation of the erythrocyte membrane due to exposure to harmful effect of free radicals exterminates their ability to change form as they pass through the capillaries and leads to intravascular hemolysis. This reactions can only be controlled through the intermediary of antioxidant substances.
This study aimed to assess the susceptibility of red cells to oxidative damage for phototherapy by assessment of the relationship between serum bilirubin level and serum MDA as an oxidant substance as a marker of lipid peroxidation and the activity of catalase as antioxidant enzyme in neonates with indirect hyperbillirubinemia before and after exposure to phototherapy.
This study were conducted on 45neonates subdivided into 3 groups group I, 15 fullterm healthy neonates without indirect hyperbilirubinemia served as control. Group II, 30 patients full term neonates with indirect hyperbillirubinemia before exposure to phototherapy . group III,the same 30 full term jaundiced neonates 72 hours after exposure to phototherapy . neonates with illness that may be associated with oxidative stress, such as circulatory failure, sepsis and asphyxia were excluded minimize the number of stress factors initiating free radicals oxidative damage.each neonate in this study was subjected to estimation of serum billirubin,serum albumin,serum uric acid,serum catalase and malonodialdyhide at the time of examination for control and before phototheraoy and 72 hours after phototherapy for jaundiced group.
Our results revealed that:
No stastically significant difference among studied group as regard to different demographic data.
No effect of sex could be detected on the levels of antioxidant and oxidant substances in both patient and control groups.
No stastically significant difference among studied group as regard to serum albumin.
Stastically significant decrease in serum uric acid (which considered as antioxidant) in jaundiced group after phototherapy.
Significant decrease in serum catalase (antioxidant enzyme) in jaundiced than control group this denotes low antioxidant level in jaundiced group, also showed significant decrease in serum catalase in jaundiced group after phototherapy showing the effect of phototherapy on the antioxidant level.
Significant increase in serum malonodialdhyde ( as marker of lipid peroxidation) in jaundiced group than in healthy contol group this denotes that jaundiced group exposed to oxidative stress,also showed significant increase in serum malonodialdhyde in jaundiced group after phototherapy this denotes the oxidative stress of phototherapy.
So, we hypothesize that low antioxidants in neonates may predispose them to increase oxidative stress, and cause hemolysis and subsequent hyperbilirubinemia.
we hypothesize also the oxidative effect of phototherapy on full term neonates during management of neonatal jaundice so phototherapy should be used with care to minimize its oxidative effect.