Levels of lipid peroxides and of some antioxidants in placenta and cord blood of newborns whose mothers smoked during pregnancy

Cigarette smoking during pregnancy increases the risk of oxidative damage and induces not only intrauterine foetal growth retardation, but also causes disturbances in postnatal growth and development. In the presented studies oxidative damage was estimated through the measurement of lipid peroxides concentration and the level of some antioxidants in placenta and in cord blood of newborns whose mothers smoked during pregnancy. We observed that the concentration of lipid peroxides was higher in cord blood and in placenta tissue (8%) than in the newborns of non-smoking mothers, but the activity of superoxide dismutase and glutathione peroxidase were lower by 20% and 16% respectively. Plasma level of vitamin A (p<0.005), vitamin E (p<0.05), fS-carotene (p< 0.0001) and total plasma antioxidant capacity (p<0.05) were significantly lower in the newborn of smoking than the non-smoking mother group. It is suggested that placental tissue protected the foetus against oxidative stress, but not sufficiently. Antioxidant activities of cord blood may also be insufficient in dismutation of free radicals and their detoxication in order to protect newborns against smoking dependent metabolic disturbances.     

Antenatal supplementation of antioxidant vitamins to reduce the oxidative stress at delivery--a pilot study

BACKGROUND: Preterm infants are at increased risk of oxidative stress and free-radical mediated diseases partly related to deficient antioxidant state. The purpose of this study was to investigate if maternal supplementation of antioxidant vitamins prior to delivery would reduce the oxidative stress in the mothers and their infants. STUDY DESIGN: A pilot case-control study. PATIENTS AND METHODS: Five mothers at risk of preterm delivery between 30 and 36 weeks were given a daily oral dose of betacarotene 20 mg, vitamin E 167.8 mg and vitamin C 1000 mg until delivery. Plasma levels of MDA and vitamins A, E and beta-carotene were measured prior to treatment in mothers and at delivery in both mothers and neonates. Seven mother-infant pairs comparable in gestation and birthweight acted as controls. RESULTS: In the supplemented group, median maternal plasma MDA at delivery was significantly lower compared to the pretreatment level (1.9 vs. 3.2 micromol/l, p=0.04) and it was also lower than the control group (1.9 vs. 3.65 micromol/l, p<0.001). In the supplemented group, median maternal plasma vitamin E at delivery was significantly higher than the levels prior to treatment (46 vs. 31 micromol/l, p=0.007) in the same group and those at delivery in the control group (46 vs. 30 micromol/l, p=0.03). There was a trend of lower plasma MDA and higher vitamin E at birth in infants born to supplemented mothers, but it did not reach statistical significance. CONCLUSION: A short supplementation of multiple antioxidant vitamins to a small sample of preterm pregnant women reduced the oxidative stress at delivery in mothers and probably in their neonates. Larger studies probably using larger doses are needed to evaluate the efficacy of this strategy.     

Compensatory antioxidant activity in blood of women whose pregnancy is complicated by cigarette smoking

In pregnancy complicated by the cigarette smoking the risk of oxidative damage depends not only on the amount of physiologically enhanced free oxygen species but may be affected by intoxication with tobacco smoke radicals. In the presented studies oxidative damage was estimated through measurement of lipid peroxidation, level of total antioxidant activity and selected antioxidants in plasma and erythrocytes of non-smoking and smoking pregnant women. No differences were found between those two groups in the level of lipid peroxidation and antioxidant activity. Plasma concentration of vitamin A was lower by 15% in smoking than in non-smoking women but vitamin E level did not change. In erythrocytes of the smoking group, concentration of reduced glutathione was 35% higher than in the non-smoking group but activity of glutathione peroxidase and concentration of vitamin E were the same. The observed changes indicate that protection of erythrocytes against free radicals may be sufficient to prevent lipid peroxidation and may manifest local and adaptive response of metabolism for tobacco smoking by pregnant women.     

Ferrokinetic and hematologic studies in cystic fibrosis patients

We investigated 28 cystic fibrosis (CF) patients to determine why hypoxia from their obstructive pulmonary disease does not produce polycythemia. Oxygen saturation was lower and erythropoietin levels were higher in CF patients than in 25 age-comparable reference subjects (90.8% and 47 mimu vs. 94.7% and 29 mimu, p less than 0.01). Hematocrit and red blood cell (RBC) indices were not different between groups. Serum vitamin and iron levels, ferrokinetics, RBC volume, and RBC survival were studied in 10 of the 28 CF patients. Total iron-binding capacity and vitamin E levels were low, and serum iron, ferritin, vitamin B12, and folate levels were normal in these patients. Red blood cell survival was minimally decreased in six patients although there was no other evidence for hemolysis. Ferrokinetics (59Fe) indicated a reduction in total erythropoiesis in only two patients. Plasma volume was high-normal in five and above normal in four CF patients; RBC mass was increased appropriately for each patient's degree of hypoxia, when compared to healthy individuals living at different altitudes. These results suggest that CF patients are able to compensate for hypoxia by increasing RBC mass; however, an expanded plasma volume prevents a detectable rise in hematocrit.     

Postnatal changes in maternal and neonatal plasma antioxidant vitamins and the influence of smoking

OBJECTIVE: To study the postnatal changes in the plasma concentrations of fat soluble antioxidant vitamins and malondialdehyde (MDA) in mothers and their newborns and their relation to smoking. DESIGN: Prospective cohort study. SETTING: Tertiary perinatal centre. SUBJECTS: Eighteen non-smoking and 14 smoking mothers and 33 infants. MAIN OUTCOME MEASURES: Plasma concentrations of vitamins E, A, and beta-carotene and MDA were measured in mothers and infants at delivery and on day 4 post partum. RESULTS: Neonatal plasma levels of vitamins E, A, and beta-carotene were significantly lower than maternal levels both at delivery and on day 4 in both groups. There was a significant postnatal increase in plasma vitamin E levels in smoking mothers and neonates of both groups. A significant postnatal increase in maternal, but not neonatal, plasma vitamin A was noted in both groups. Cord plasma vitamin E levels were significantly lower in infants of smoking mothers (mean 4.7 v 6.5 micromol/l, p = 0.041). Plasma MDA was paradoxically lower in smoking mothers at delivery (3.19 v 4.01 micromol/l, p = 0.03) and on day 4 (1.37 v 3.29 micromol/l, p = 0.005) and in infants of the smoking group on day 4 (2.18 v 3.12 micromol/l, p = 0.014). Also, there was a significant postnatal fall in plasma MDA levels on day 4 in mothers and infants in the smoking group. CONCLUSIONS: The postnatal changes in plasma vitamin E were more pronounced in the smoking group. The postnatal changes in plasma vitamins A and beta-carotene were similar in both groups. The rapid decline in plasma MDA in smoking mothers and their infants suggests withdrawal of oxidative stress from smoking around delivery. This coincided with the increase in plasma vitamin E.     

Markers of oxidative stress and antioxidant activity in plasma and erythrocytes in neonatal respiratory distress syndrome

Markers of oxidative stress and antioxidant activity in plasma and erythrocytes were studied for 14 d after birth in infants with neonatal respiratory distress syndrome ( n = 9) and controls ( n = 36). In plasma, the total radical trapping antioxidant capacity and the chain-breaking antioxidants vitamin C, sulfhydryl groups and bilirubin were similar. The differences in uric acid levels were not consistent, but vitamin E levels and vitamin E/total-lipid ratio were lower in the neonatal respiratory distress group ( p < 0.01). In erythrocytes, the antioxidant enzymes glutathione peroxidase, glutathione reductase and superoxide dismutase did not differ postnatally. Indicators of oxidative damage in plasma (sulfhydryl/protein ratio and thiobarbituric acid reactive substances) showed the same postnatal course in both groups and were not influenced by oxygen therapy. In erythrocytes the reduced/oxidized glutathione ratio showed no consistent differences. In conclusion, this study, using erythrocytes and plasma, does not provide convincing evidence of oxidative damage and diminished antioxidant defenses in preterm infants with neonatal respiratory distress syndrome.     

Erythrocyte membrane lipid peroxidation before and after vitamin E supplementation in children with cholestasis

In 10 children with chronic cholestasis and without neurologic signs, we evaluated lipid peroxidation and vitamin E levels in serum and in the erythrocytes before and after a therapeutic trial with alpha-tocopherol. We also studied the effects of vitamin E administration on hematocrit and hemoglobin values and on reticulocyte and erythrocyte counts. Plasma and erythrocyte malonyldialdehyde (MDA) values were significantly higher compared with normal control values, whereas plasma and erythrocyte tocopherol measurements were lower. Oral administration of high doses of vitamin E (300 mg/day for 15 days) resulted in lower serum MDA levels, whereas serum vitamin levels did not change significantly. In erythrocytes, the MDA decreased but not to control levels, and vitamin E increased but to lower values than normal. Hematologic values also improved. We conclude that longer treatment might be necessary to completely reverse the oxidative damage associated with vitamin E deficiency in children with cholestasis.     

Is Supplementation Efficacious in Maintaining Adequate Plasma Levels of Vitamin A and E for Thalassemic Patients Undergoing Hematopoietic Stem Cell Transplantation? A Cross-Sectional Study

Objective: Thalassemia along with hematopoietic stem cell transplantation (HSCT) can lead to major oxidative stress. Vitamins A and E are antioxidants which protect membrane from lipid peroxidation. We sought to determine for the first time, whether vitamins A and E supplementation is efficacious in maintaining or increasing plasma level of these vitamins in thalassemic children undergoing HSCT. Methods: A cross-sectional study was performed on 50 children with β-thalassemia major hospitalized for HSCT. Patients took a daily multivitamin. Plasma vitamins A and E levels were measured at four different times: on admission, HSCT day (day 0), day 7 and day 14 after HSCT. Findings : Plasma vitamin A and E were abnormal on admission in most patients (62.0% and 60.0% respectively). Ratio of patient with normal to abnormal plasma level of the vitamins improved from baseline to a peak on day 7 then deteriorated afterward until day 14. There was an increasingly positive correlation between daily oral intake and plasma vitamin A at different times, but plasma vitamin E showed inverse correlation at first which tended towards no correlation subsequently. In multivariate analysis, supplementation significantly changed plasma level of vitamin A at different measurement time (P=0.001) within study subjects. But, plasma level of vitamin E showed no significant difference (P=0.2). Conclusion: Our findings suggest that oral supplementation could have beneficial effects due to increasing plasma vitamin A level and preventing plasma vitamin E depletion.Key Words: Thalassemia, Hematopoietic Stem Cell Transplantation, Vitamin A, Vitamin E, Dietary Supplements     

Plasma methotrexate, red blood cell methotrexate, and red blood cell folate values and outcome in children with precursor B-acute lymphoblastic leukemia: a report from the Children's Oncology Group

Plasma steady state methotrexate (MTX) level and red blood cell (RBC) MTX and folate concentrations were evaluated in 1124 children with newly diagnosed acute lymphoblastic leukemia enrolled in the Pediatric Oncology Group studies 9005 (lower risk; Regimens A and C) and 9006 (higher risk; Regimen A). These regimens included intermediate-dose MTX (1 g/m) given as a 24 hours infusion every other week for 12 doses during intensification. Plasma MTX level was evaluated at the end of MTX infusions. RBC MTX and folate concentrations were measured at the end of intensification. The 5 year continuous complete remission was 76±1.4% versus 85±3.0% for those patients with steady state MTX levels less than or equal to and greater than 14 μM, respectively (P=0.0125). Hispanic children had significantly reduced median steady state MTX levels, 8.7 μM, compared with non-Hispanic children, 9.95 μM (P=0.0015), but this did not correlate with a difference in outcome. Neither RBC MTX, RBC folate, nor the RBC MTX:folate ratio identified children at increased risk of failure.     

Deficiency of vitamins E and A in cystic fibrosis is independent of pancreatic function and current enzyme and vitamin supplementation

Abstract The aim of this study was to evaluate to what extent serum vitamins A and E in cystic fibrosis are affected by the underlying disease, pancreatic sufficiency or insufficiency, meconium ileus, nutritional status, age and treatment (enzyme and vitamin supplementation). Serum vitamin A and E levels were determined by high performance liquid chromatography in 210 cystic fibrosis patients, subdivided according to clinical condition into four subgroups (unsupplemented pancreatic insufficiency, supplemented meconium ileus, pancreatic sufficiency, supplemented pancreatic insufficiency) and compared with 42 control subjects. Vitamin A and E levels were generally lower in cystic fibrosis patients than in controls (P<0.002 andP<0.001 respectively). Subjects with pancreatic insufficiency regularly receiving enzyme and vitamin supplementation had significantly lower vitamin A (P<0.05) and vitamin E (P<0.01) levels than controls. In subjects with pancreatic sufficiency only vitamin A was significantly lower than in controls (P<0.01). Vitamin levels were not age-dependent in cystic fibrosis, and no significant correlation with standardized body weight (Z-score) was observed.Conclusion Cystic fibrosis patients show a clear tendency to vitamin A and E deficiency, irrespective of pancreatic function, body weight and standardized supplementation with pancreatic extract and liposoluble vitamins. Since the clinical significance of this deficiency is still not clear, longitudinal studies of cystic fibrosis patients with and without adequate vitamin supplementation are required.     

Antioxidant levels in cord blood of low birth weight newborns

We evaluated the antioxidant status of 82 healthy term low birth weight (LBW) newborns and equal number of gestation and sex matched controls weighing <2500 g by measuring vitamin A and E, superoxide dismutase, catalase and glutathione peroxidase in cord serum. Levels of vitamin A and E, superoxide dismutase and catalase were significantly lower and glutathione peroxidase significantly higher in LBW babies compared to controls, with the lowest levels found in babies showing more severe growth restriction (<2000 g). We conclude that LBW newborns are deficient in several important antioxidants which may predispose them to higher oxidative stress.     

Antioxidants in HIV positive children

Objective  To assess the antioxidant status in HIV positive children. Methods  HIV positive children under the age group of 3–12 years from lower socio-economic strata were chosen for the study (Group 1). The values were compared with normal children (Group 2) not suffering from any disease in the same age group and similar socio-economic strata. The antioxidants chosen for the present study were vitamin A (Retinol), vitamin C (Ascorbic acid) and vitamin E (α tocopherol). Results  Results obtained were subjected to statistical analysis using student ‘t’ test (in the present study ‘z’ test was applied). The antioxidants vitamin A, C and E decreased in HIV positive children as compared to controls. Vitamin A was significant to the level of p< 0.01 and vitamin C and E to the level of p< 0.001 and p< 0.02 respectively. Conclusion  The decrease in antioxidants A, C and E in HIV positive children is due to increased utilization of antioxidant micronutrients because of increased oxidative stress caused due to free radicals.     

The vitamin B12-deficient rat as a possible model of ketotic hyperglycinemia.

The rate of oxidation to respiratory CO2 of both carbon 1 of propionate and carbon 1 of glycine was decreased significantly in vitamin B12-deficient rats, to 50% and 82% of the control rate, respectively. The activity of the glycine synthase system was reduced during vitamin B12 deficiency to 25% of control activity. Serine hydroxymethyltransferase activity was similar for vitamin B12-deficient and control rats. Plasma glycine concentration in vitamin B12-deficient rats (253 +/- 16 nmol/ml) did not differ significantly from that of control rats (226 +/- 12 nmol/ml). Propionate oxidation was significantly impaired in biotin-deficient rats. However, this impairment, to 66% of the control rate, was not as large as that generated by vitamin B12 deficiency. In contrast to the result obtained in vitamin B12-deficient animals, no significant decrease in glycine oxidation could be demonstrated in biotin-deficient animals. Plasma glycine concentration of fasted biotin-deficient rats (339 +/- 26 nmol/ml) did not differ significantly from that of their controls (371 +/- 32 nmol/ml).     

Increased oxidative stress in infants exposed to passive smoking

The purpose of this study was to assess the effect of passive cigarette smoking on the oxidative and anti-oxidative status of plasma in infants. Eighty-four infants aged 6–28 weeks were divided into two groups: the study group included infants who had been exposed to passive smoking via at least five cigarettes per day for at least the past 6 weeks at home, while the control group included infants who had never been exposed to passive smoking. The antioxidative status of plasma was assessed by the measurement of individual antioxidant components: vitamin C, albumin, bilirubin, uric acid, thiol contents and total antioxidant capacity (TAC 1 and TAC 2). Oxidative status was assessed by the determination of total peroxide levels and the oxidative stress index (OSI 1 and OSI 2). Plasma vitamin C, thiol concentration and TAC 1 and TAC 2 levels were significantly lower, whereas plasma total peroxide levels and OSI 1 and OSI 2 were significantly higher, in passive smoking infants than in the controls (P<0.01). We conclude that passive smoking has a negative impact on numerous parts of the antioxidant defence system in infants, and exposes them to potent oxidative stress.     

Vitamin E status in hypercholesterolemic children

The prime role of oxidized low-density lipoprotein in the pathogenesis of atherosclerosis is almost universally accepted. Fat soluble antioxidant vitamin E associated with lipoproteins, appears to have antiatheroma properties. In the presented studies concentration of vitamin E and the relationship between tocopherol and lipids were studied in blood of hypercholesterolemic children. Level of vitamin E was determined by high-performance liquid chromatography (HPLC) method. Compared with normocholesterolemic children, hypercholesterolemic patients had a significantly lower red blood cell vitamin E content (2.55 +/- 0.19 micromol/l vs 3.15+/- 0.33 micromol/l; p<0.005) in spite of their higher plasma vitamin E concentration (27.9 +/- 8.3 micromol/l vs 21.01 +/- 3.6 micromol/l; pl;0.001). In the group of patient tocopherol-to-total cholesterol and tocopherol-to-lipids ratio was statistically lower compared to those in the control group. In hypecholesterolemic children vitamin E positively correlated with total cholesterol (r=0.43; p<0.02), LDL-C (low-density lipoprotein cholesterol) (r=0.42; p<0.02) and lipids (triglycerides + total cholesterol) (r=0.45; p<0.02). This study demonstrates that total plasma vitamin E concentration is not a suitable predictor of cell vitamin E status. Our results suggested that the tocopherol of erythrocytes and vitamin E to lipids ratio in plasma, could be more meaningful indicators to evaluate the vitamin E status in hypercholesterolemic children.     

A modified vitamin regimen for vitamin B2, A, and E administration in very-low-birth-weight infants

INTRODUCTION: Very-low-birth-weight (VLBW; birth weight, <1,500 g) infants receive preterm infant formulas and parenteral multivitamin preparations that provide more riboflavin (vitamin B2) than does human milk and more than that recommended by the American Society of Clinical Nutrition. VLBW infants who are not breast-fed may have plasma riboflavin concentrations up to 50 times higher than those in cord blood. The authors examined a vitamin regimen designed to reduce daily riboflavin intake, with the hypothesis that this new regimen would result in lower plasma riboflavin concentrations while maintaining lipid-soluble vitamin levels. METHODS: Preterm infants with birth weight < or =1,000 g received either standard preterm infant nutrition providing 0.42 to 0.75 mg riboflavin/kg/day (standard group), or a modified regimen providing 0.19 to 0.35 mg/kg/day (modified group). The modified group parenteral vitamin infusion was premixed in Intralipid. Enteral feedings were selected to meet daily riboflavin administration guidelines. Plasma riboflavin, vitamin A, and vitamin E concentrations were measured weekly by high-performance liquid chromatography. Data were analyzed with the independent t test, chi, and analysis of variance. RESULTS: The 36 infants (17 standard group, 19 modified group) had birth weight and gestational age of 779 +/- 29 g and 25.5 +/- 0.3 weeks (mean +/- SEM) with no differences between groups. Modified group infants received 38% less riboflavin (0.281 +/- 0.009 mg/kg/day), 35% more vitamin A (318.3 +/- 11.4 microg/kg/day), and 14% more vitamin E (3.17 +/- 0.14 mg/kg/day) than standard group infants. Plasma riboflavin rose from baseline in both groups but was 37% lower in the modified group during the first postnatal month (133.3 +/- 9.9 ng/mL). Riboflavin intake and plasma riboflavin concentrations were directly correlated. Plasma vitamin A (0.222 +/- 0.022 microg/mL) and vitamin E (22.26 +/- 1.61 /mL) concentrations were greater in the modified group. CONCLUSIONS: The modified vitamin regimen resulted in reduced riboflavin intake and plasma riboflavin concentration, suggesting plasma riboflavin concentration is partially dose dependent during the first postnatal month in VLBW infants. Modified group plasma vitamin A and vitamin E concentrations were greater during the first month, possibly because the vitamins were premixed with parenteral lipid emulsion. Because of the complexity of this protocol, the authors suggest that a parenteral multivitamin product designed for VLBW infants which uses weight-based dosing should be developed.     

Anti-oxidant vitamins and steroid responsive nephrotic syndrome in Indian children

OBJECTIVE: In recent years, it has been proposed that nephrotic syndrome is a consequence of an imbalance between oxidant and anti-oxidant activity. In the present study, the levels of micronutrient anti-oxidant vitamins (vitamin E, vitamin C, carotene and riboflavin) in Indian children with steroid responsive nephrotic syndrome were investigated. Their levels were measured during the acute proteinuric phase of the disease, as well as during clinical recovery (remission), in order to understand the possible role of nutritionally modifiable anti-oxidants in the aetiopathogenesis of the disease. METHODS: The study was a hospital based, prospective cohort study. Serum and erythrocyte vitamin E, leucocyte vitamin C, serum carotene, erythrocyte riboflavin activity and serum malonyldialdehyde (MDA) levels were measured in 30 consecutive cases of children with nephrotic syndrome (International Study of Kidney Diseases in Children (ISKDC) criteria) during the proteinuric phase of the disease and at 4 weeks after remission was induced by steroid therapy. The same biochemical parameters were measured in healthy siblings (controls) of the 30 patients. RESULTS: Mean vitamin E (serum and erythrocyte), vitamin C and carotene were significantly lower during the proteinuric phase of the disease, and there was decreased erythrocyte riboflavin activity. There was significant elevation in the serum level of MDA during this phase. In addition, all these parameters tended to improve during remission, although complete normalization did not occur. CONCLUSION: These vitamins were active in performing their anti-oxidant function, as indicated by significant depression in their levels during the acute (proteinuric) phase, followed by partial recovery during remission. It may be concluded that steroid responsive nephrotic syndrome in children is associated with oxidative stress.     

Docosahexaenoic acid status of term infants fed breast milk or infant formula containing soy oil or corn oil.

The objective of this study was to compare circulating lipid docosahexaenoic acid [22:6(n-3), DHA] levels in term infants fed a powdered (CORN oil) or liquid (SOY oil) infant formula or human milk (HM). Infants whose mothers chose not to breast feed were randomly assigned to the CORN or SOY formula group. The formula fat differed in linolenic acid [18:3(n-3)] content: it was 0.8% for the CORN and 4.8% for the SOY. Linoleic acid [18:2(n-6)] was 31.5 and 34.2% fatty acids in the CORN and SOY formula, respectively. The formulas or HM were fed from birth through 8 wk of age, and growth and the plasma and red blood cell (RBC) phospholipid fatty acid composition was determined at 3 d, 4 wk, and 8 wk of age. Growth did not differ among groups. The plasma phospholipid and RBC phosphatidylethanolamine DHA was similar in the CORN and SOY formula groups at all ages. Plasma and RBC phosphatidylethanolamine levels of DHA were significantly lower in infants fed the CORN or SOY formula than in infants fed HM during wk 4 and 8. Plasma and RBC 22:5(n-6) was not increased in the formula groups at any age. The formula content of linolenic acid had no effect on the RBC or plasma DHA levels of the infants. The biologic or functional significance of the lower plasma and RBC DHA in infants fed formula rather than HM is unknown. The need for a dietary source of DHA and specificity of plasma or RBC phospholipid DHA as a measure of desaturation and elongation of linolenic acid in developing organs remains uncertain.     

Oxidant-antioxidant status in Egyptian children with sickle cell anemia: a single center based study

Objectivethe present study was conducted to investigate the oxidant-antioxidant status in Egyptian children with sickle cell anemia.Methodsthe serum levels of total antioxidant capacity (TAO), paraoxonase (PON), vitamin E, nitrite, and malondialdehyde (MDA) were measured in 40 steady state children with homozygous sickle cell anemia (24 males and 16 females) and 20 apparently healthy age- and gender-matched controls.Resultsmean serum TAO, PON, vitamin E, and nitrite levels were significantly lower in the group with sickle cell anemia, whereas mean serum MDA was significantly higher in these children compared to controls. No significant differences in mean levels of TAO, PON, nitrite, vitamin E, and MDA were found in sickle cell anemia patients receiving hydroxyurea when compared with those not receiving hydroxyurea. A significant negative correlation between serum nitrite and the occurrence of vaso-occlusive crises (VOC) was observed (r = −0.3, p = 0.04). PON level was found to be positively correlated with patients’ weight and BMI (r = −0.4, p = 0.01; r = −0.7, p < 0.001, respectively), but not with frequency of VOC. The area under the curve of serum nitrite in predicting occurrence of VOC was 0.782, versus 0.701 for PON, and 0.650 for TAO (p = 0.006). Serum MDA was not correlated with nitrite, PON, TAO, or vitamin E levels. No significant correlations were detected between serum nitrite and hemoglobin or antioxidant enzymes.Conclusionchildren with sickle cell anemia have chronic oxidative stress that may result in increased VOC, and decreased serum nitrite may be associated with increases in VOC frequency. A novel finding in this study is the decrease in PON level in these patients, which is an interesting subject for further research.     

Selenium and vitamin E in mucoviscidosis

Selenium and vitamin E are two important components which protect membrane lipids from oxidative damage. Recently an abnormal fatty acid turnover in the membrane phospholipids was found in cystic fibrosis (CF). We studied vitamin E and selenium status in 26 CF children compared to a control group. we measured selenium concentration in plasma and erythrocytes using flameless atomic absorption. The measure of erythrocyte glutathione peroxidase activity allowed a functional assessment of selenium. Total plasma tocopherol concentrations (HPLC) were referred to total lipids. The vitamin E and selenium levels in not yet treated children (n = 6) were very low, with an important decrease in glutathione peroxydase activity. The antioxidative agents deficiency was mild in children with pancreatic enzyme replacement and vitamin E supplementation (n = 20). In the 2 groups, this deficiency was combined and may play a role in CF membrane abnormalities.