Resuscitation with supplementary oxygen induces oxidative injury in the cerebral cortex.

Isoprostanes, neuroprostanes, isofurans, and neurofurans have all become attractive biomarkers of oxidative damage and lipid peroxidation in brain tissue. Asphyxia and subsequent reoxygenation cause a burst of oxygen free radicals. Isoprostanes and isofurans are generated by free radical attacks of esterified arachidonic acid. Neuroprostanes and neurofurans are derived from the peroxidation of docosahexanoic acid, which is abundant in neurons and could therefore more selectively represent oxidative brain injury. Newborn piglets (age 12-36 h) underwent hypoxia until the base excess reached -20 mmol/L or the mean arterial blood pressure dropped below 15 mm Hg. They were randomly assigned to receive resuscitation with 21, 40, or 100% oxygen for 30 min and then ventilation with air. The levels of isoprostanes, isofurans, neuroprostanes, and neurofurans were determined in brain tissue (ng/g) isolated from the prefrontal cortex using gas chromatography-mass spectrometry (GC/MS) with negative ion chemical ionization (NICI) techniques. A control group underwent the same procedures and observations but was not submitted to hypoxia or hyperoxia. Hypoxia and reoxygenation significantly increased the levels of isoprostanes, isofurans, neuroprostanes, and neurofurans in the cerebral cortex. Nine hours after resuscitation with 100% oxygen for 30 min, there was nearly a 4-fold increase in the levels of isoprostanes and isofurans compared to the control group (P=0.007 and P=0.001) and more than a 2-fold increase in neuroprostane levels (P=0.002). The levels of neuroprostanes and neurofurans were significantly higher in the piglets that were resuscitated with supplementary oxygen (40 and 100%) compared to the group treated with air (21%). The significance levels of the observed differences in neuroprostanes for the 21% vs 40% comparison and the 21% vs 100% comparison were P<0.001 and P=0.001, respectively. For neurofurans, the P values of the 21% vs 40% comparison and the 21% vs 100% comparison were P=0.036 and P=0.025, respectively. Supplementary oxygen used for the resuscitation of newborns increases lipid peroxidation in brain cortical neurons, a result that is indicative of oxidative brain damage. These novel findings provide new knowledge regarding the relationships between oxidative brain injury and resuscitation with oxygen.

Superoxide dismutase and catalase activity in naturally derived commercial surfactants.

Despite the role of reactive oxygen species in the development of respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD) in preterm infants, the anti-oxidant properties of commercial surfactants have never been studied. We measured the superoxide dismutase (SOD) and catalase (CAT) activity, the scavenger activity against hydrogen peroxide (H(2)O(2)), and its changes after the addition of SOD and CAT in four natural surfactants, namely Infasurf, Curosurf, Survanta, and Alveofact. We found that they contain measurable amount of SOD and CAT. Curosurf and Survanta seem to have higher antioxidant effect than Infasurf and Alveofact. Moreover, the highest phospholipid concentration and recommended dose of Curosurf imply that its scavenger activity for each treatment dose in preterm infants is likely higher than that of Survanta. Finally, the supplementation with SOD and CAT induced a remarkable increase of antioxidant action in all studied surfactants.

Glutathione synthesis rates after amino acid administration directly after birth in preterm infants.

BACKGROUND: The availability of glutathione, the main intracellular antioxidant, is compromised in preterm neonates. A possible explanation is the low availability of substrate for synthesis, because many neonatologists are reluctant to administer amino acids in the direct postnatal period for fear of intolerance. OBJECTIVE: The objective of the study was to determine the effects of amino acid administration directly after birth on glutathione synthesis rates and markers of oxidative stress. DESIGN: Premature infants (<1500 g) received from birth onward either dextrose (control group; n = 10) or dextrose plus 2.4 g amino acids . kg (- 1) . d(-1) (intervention group; n = 10). On postnatal day 2, [1-(13)C]glycine was administered to determine glutathione fractional synthesis rates (FSR(GSH)) and absolute synthesis rates (ASR(GSH)) in erythrocytes. In plasma, advanced oxidized protein products and dityrosine, both markers of oxidative stress, were measured. The results are expressed as means +/- SDs. RESULTS: The FSR(GSH) was not different between groups: 44 +/- 6 and 48 +/- 9%/d in the control and intervention groups, respectively (P = 0.28). The concentration of erythrocyte glutathione was higher (P < 0.001) in the intervention group (2.28 +/- 0.35 mmol/L) than in the control group (1.73 +/- 0.37 mmol/L). ASR(GSH) values were 6.5 +/- 1.5 and 11.3 +/- 1.9 mg . kg(-1) . d(-1) in the control and intervention groups, respectively (P < 0.001). Advanced oxidized protein products and dityrosine concentrations were not significantly different between groups. CONCLUSIONS: Amino acid administration directly after birth increases ASR(GSH) in preterm infants. Our data are consistent, however, with higher glutathione concentrations rather than a higher FSR(GSH). Greater availability of glutathione, nevertheless, did not decrease markers of oxidative stress.

Magnesium profile in autism.

The aim of the present study was to determine and compare plasma and erythrocyte concentrations of magnesium in 12 autistic children (10 boys, 2 girls), 17 children with other autistic spectrum disorders (14 boys, 3 girls), 5 girls with classic Rett syndrome, and 14 normal children (7 boys, 7 girls) of the same age. No differences in intracellular Mg were found between controls and pathological subjects; however, autistic children and children with other autistic spectrum disorders had significantly lower plasma concentrations of Mg than normal subjects (p=0.013 and p=0.02, respectively). Although our study population was small, we conclude that children with autistic spectrum disorders require special dietary management. If these cases are diagnosed at an early stage, they can be helped through diet.

Selenium status, birth weight, and breast-feeding: pattern in the first month.

Selenium (Se) is an essential nutritional element for humans. A low Se status has been documented in formula-fed small-for-gestational age (SGA) newborns in the first month of life. The aim of the study was to compare the nutritional selenium status in adequate-for-gestational age (AGA) and in SGA newborns in the first month of life in relation to feeding type. Se status was assessed by plasma and erythrocyte concentrations, determined by pulsed Zeeman effect-atomic absorption spectrophotometry. We studied 210 newborns divided in groups according to birth weight (129 AGA, 81 SGA ) and feeding type (breast milk, formula, mixed) in wk 1-4 of postnatal life. Erythrocyte Se levels are affected neither by feeding type nor by birth weight. Se plasmatic concentrations were lower in SGA than in AGA newborns. Significant differences in mean plasma concentrations were found between formula-fed and breast-fed (p=0.013) and between formula-fed and mixed-fed (p=0.006) SGA newborns. The difference was not significant in AGA neonates. Breast-fed SGA newborns consistently showed higher plasma Se concentrations than formula-fed newborns. Unless supplemented from birth, Se intake will be inadequate in bottle-fed SGA infants.