Red Cell Superoxide Dismutase Research Articles

Effect of chloroquine, methylene blue and artemether on red cell and hepatic antioxidant defence system in mice infected with Plasmodium yoelii nigeriensis

Reactive oxygen species are mediators of tissue injury and are involved in malaria infection. In this study, the status of red cell and hepatic oxidative stress and antioxidant defence indices were investigated during Plasmodium yoelii nigeriensis (P. yoelii) infection, and treatment with chloroquine (CQ), methylene blue (MB) or artemether (ART) in mice. P. yoelii infection caused a significant (p < 0.05) increase in oxidative stress as evidenced by the elevated level of malondialdehyde. This was followed by a significant decrease (p < 0.05) in hepatic antioxidant defence indices, viz. reduced glutathione (GSH) and glutathione-S-transferase (GST). Also, the red cell catalase activity was significantly (p < 0.05) lower in malaria infection, while there was no significant difference (p > 0.05) in the superoxide dismutase (SOD) activity of infected mice when compared to untreated normal. Treatment of infected mice with the three antimalarials showed that the drugs suppressed the parasitaemia in the order CQ > ART > MB. CQ, MB and ART treatment of infected mice caused a significant (p < 0.05) increase in the levels of hepatic GSH and GST. Specifically, CQ, MB and ART increased the levels of hepatic GSH by 108, 124 and 98 %, respectively, at day 6. Also, ART treatment of infected mice significantly (p < 0.05) elevated the red cell SOD level by 200 % at day 3. Taken together, the findings suggest that the antimalarial effect of CQ, MB and ART countered the P. yoelii-induced oxidative stress leading to the elevation of enzymatic and non-enzymatic antioxidants in the host system.

Red cell antioxidant enzymes and prognostic indexes in patients with burns

Red cell superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) were measured in 66 burned patients (57 men, 9 women, age 16–78 years). BSAB varied from 15 to 93% and ABSI from 3 to 14 points. In the first week after injury the activity of SOD was significantly decreased as compared with the activity of the enzymes in the control group and was also below the reference values. Later the activity of SOD increased up to the normal range. The activity of CAT followed a similar pattern but the differences were not significant. No significant changes in red cell GPX were found during the monitored period. We did not find any significant association between the antioxidant enzyme activities and the markers of burns severity. On the other side there was a significant indirect association between the change of SOD activity (calculated as a difference between the first week values after the injury and the activities measured later) and BSAB.

Micronutrient, Antioxidant, and Oxidative Stress Status in Children With Severe Cerebral Palsy

Markers indicative of micronutrient and antioxidant status in children with cerebral palsy (CP) were explored due to these children's well-documented issues with food intake and the limited biochemical literature. Children aged 4 to 12 years with marked CP (n = 24) and controls (n = 24) were recruited. The CP group represented orally (O) or enterally fed (E) children. Concentrations of red cell folate (RCF), magnesium, superoxide dismutase (SOD), glutathione reductase, and peroxidase were measured, as well as serum methylmalonic acid and vitamin C. Plasma hemoglobin, C-reactive protein, α-tocopherol, cholesterol, zinc, protein carbonyls, and total antioxidant capacity were also quantified. Data are reported as mean (SD) and z scores where values differ with age. Many similarities existed, but zinc z scores were reduced in O (-1.10 [0.83]) vs controls (-0.54 [0.54]) (P < .05), as well as for glutathione reductase in O (10.15 [1.69]) vs E (12.22 [2.41]) and controls (11.51 [1.67]) (P < .05). RCF was greatly increased in E (1422 [70]) vs O (843 [80]) and controls (820 [43]) (P < .001). SOD was decreased in E (24.3 [1.4]) vs controls (27.0 [2.8]) (P < .05). Considering their vast impact on physiology, micronutrients should be routinely monitored in orally fed children with swallowing disorders and dietary limitations. Excessive intakes, particularly long term in enterally fed children, should also be monitored in view of their potential for competitive inhibition, particularly at high levels.

Effects of Atenolol, Labetalol and Methyldopa on Endogenous Antioxidants In-vitro

Abstract The aim of this study was to investigate whether atenolol, labetalol and methyldopa, which are commonly used for the treatment of hypertension in pregnancy, can induce antioxidant activity. Reactive oxygen species scavengers (plasma thiol, red cell lysate thiol, red cell superoxide dismutase, red cell membrane thiol and plasma glutathione) were measured after incubation of peripheral blood with atenolol and methyldopa, respectively. The results showed that atenolol and labetalol could significantly raise the levels of plasma thiol and membrane thiol but had no effects on lysate thiol, superoxide dismutase and glutathione. The effects on membrane thiol occurred after 60 min incubation and on plasma thiol after 120 min incubation. The data also suggest that atenolol and labetalol at lower concentrations tend to have additive effects on reactive oxygen species scavengers but at higher concentrations do not. Methyldopa had no significant effect on any of the parameters measured. These findings suggest that atenolol and labetalol are able to induce higher levels of antioxidant activity.

Oxidant and Antioxidant Status in Childhood Nephrosis and its Relation to Hyperlipidemia

Background: Oxidative damage by free radicals has been implicated in a number of clinical disorders including renal injury. An abnormality in the oxidative system in patients with nephrotic syndrome (NS) has been reported.Objective: To assess the oxidant status (red cell MDA) and antioxidant status (red cell GSH, SOD' and plasma vitamin E, copper, zinc) in relation to hyperlipidemii in children with active nephrotic syndrome (NS) and during remission.Methods: This study was conducted on 65 children with NS; 35 with active NS (Group 1) & 30 with NS during remission (Group 2) and 20 healthy controls. Red cell glutathione (GSH), superoxide dismutase (SOD) and malonfiialdehyde (MDA) concentrations as well as plasma levels of vitamin E, copper, zinc and plasma lipids (total cholesterol ТС, triglycerides high density lipoprotein cholesterol and low density lipoprotein cholesterol LDL-C) were measured in children with NS and in controls.Results: SOD concentrations significantly increased in both group I & group 2 when compared to the controls. MDA concentrations significantly increased in both group 1 & group 2 compared to the controls. GSH concentrations along with plasma vitamin E concentrations significantly decreased in both group I & group 2 compared to controls. A significant decrease in plasma copper and zinc concentrations was observed in group 1 compared to controls. However, a non-significant decrease in plasma copper and zinc concentra-tions was observed in group 2 compared to controls. Plasma TC, TG, LDL-C concentrations significantly increased while plasma HDL-C significantly decreased in both group 1 & group 2 compared to controls. Significant +ve correlation was found between MDA and each of TC, TG, LDL-C, while significant -ve correlation existed between MDA and HDL-C. Significant -ve correlations existed between each of albumin, SOD, vitamin E, zinc, copper and each of TC, TG, LDL-C. Meanwhile, significant +ve correlations existed between HDL-C and each of albumin, SOD, vitamin E, zinc and copper.Conclusion: Increased pro-oxidant status with compensatory changes in antioxidant concentrations occur in children with NS. These changes are linked to lipid disorders in NS patients and may be related to the pathogenesis of NS.

Alpha‐tocopherol and ginger are protective on Cyclophosphamide‐induced gonadal toxicity in adult male albino rats

ABSTRACT Background and aim: The ameliorative effect of alpha‐tocopherol (vitamin E) and Zingiber officinale (ginger) on cyclophosphamide‐induced gonadal toxicity are studied in adult male rats. Methods: Forty‐four adult male albino rats were used in this study in four groups. Group I served as normal control, groups II–IV received cyclophosphamide intraperitoneally at a daily dose of 20 mg per kg body weight for 7 days but group III and IV received supplementary vitamin E and ginger respectively for two weeks starting one week before the start of the cyclophosphamide. Results: The sperm counts of the normal (I), cyclophosphamide treated group alone (II), cyclophosphamide with vitamin E (III) and with ginger (IV) showed 23.5, 8.5, 14.2, 18.1 (× 106 per cubic milimeter) and abnormal morphology was most frequently found in group II (16.2%) followed by groups III (6.3%), IV (5.9%) and I (2.2%). Testosterone level, malondialdehyde enzyme activity, and red cell catalase and superoxide dismutase activities also correlated well with the morphological parameters. Incidence of apoptosis and the number of TUNEL‐stained cells as well as pathological findings in reproductive organs also correlated with these parameters. Conclusion: Both vitamin E and ginger have protective effect from the cyclophosphamide‐induced gonadal toxicity. The mechanism is largely unknown but empirical supplementation of vitamin E and ginger would be recommended before and during cyclophosphamide chemotherapy.

Monitoring antioxidant enzymes in red cells during allergen immunotherapy

The aim of this report was to answer the question how specific immunotherapy influences the antioxidant enzyme system in patients with respiratory allergy and in longer perspective to find markers suitable to assess the efficacy of treatment. In open prospective randomised study 28 patients (18 females and 10 males, age 14-48 years) with seasonal respiratory allergy were treated with allergen immunotherapy. Subjects received subcutaneous therapy with allergens absorbed on calcium phoshate or aluminium hydroxide and were analyzed by the established protocol at the beginning, after three and 12 month of the treatment. In all treatment group red cell superoxide dismutase and glutathione peroxidase activities were in the normal range in allergic patients both before and during the treatment. Catalase activity in the allergic patients was lower as compared with controls and a significant increase of the enzyme activity occurred during and at the end of the treatment. In patients treated with calcium phosphate adsorbed allergen there was a continous increase of catalase activity from beginning up to the end of observation. In the case of the aluminium hydroxide treatment there was an increase from the baseline values up in the third month of the treatment and a decrease on the 12th month. In summary, the present results open the question that allergen immunotherapy may cause imbalance of oxidants and antioxidants. To support our findings larger controlled field studies are needed.

Red cell superoxide dismutase activity in sporadic amyotrophic lateral sclerosis

Specific biologic markers are not available for definitive diagnosis and monitoring of disease progression in sporadic amyotrophic lateral sclerosis (SALS). Oxidative stress plays a role in ALS pathogenesis. The purpose of this study was to determine the association between Cu/Zn superoxide dismutase (SOD1) activity, diagnosis and prognosis. The present study included 25 SALS patients (SALS group; age 51 ± 12 years) and 10 healthy subjects (age 45 ± 5 years) as a control group. Patients were divided into groups representing four levels of diagnostic certainty of ALS in accordance with the El Escorial Revisited criteria. The disease state was determined using the modified ALS health state scale of Riviere et al. ( Arch Neurol 1998: 55;526–8). Red-cell SOD1 activity was determined by spectrophotometry. SOD1 activity in red cells was compared statistically with diagnostic criteria and disease state. Red cell SOD1 activity was high in all SALS patients, but there was no significant association between enzyme activity and diagnostic criteria and disease state. In this preliminary study, we did not find any correlation between SOD1 activity level and diagnosis or prognosis. Measured SOD1 activity sometimes supports ALS diagnosis, but it is neither a specific nor a prognostic factor.

Increased Oxidative Stress in Acute Exacerbations of Asthma

Oxidant-antioxidant imbalance may play an important role in the pathogenesis of asthma, especially during acute exacerbations. To compare the systemic oxidant-antioxidant status in patients with acute exacerbations and stable asthma, we measured a wide range of parameters of oxidant-antioxidant balance in leukocytes, plasma, and red cells of 32 patients with acute exacerbations and 97 patients with stable asthma. These included measurement of superoxide anion generation by leukocytes, lipid peroxidation (measured as TBARS), total nitrates and nitrites, protein carbonyls, and protein sulfhydryls in plasma. Antioxidant status was evaluated by measuring the red cell superoxide dismutase and catalase activity, total blood glutathione, glutathione peroxidase activity in red cell and plasma, and total antioxidant capacity (assessed as ferric reducing antioxidant power) in plasma. Plasma total antioxidant capacity and total protein sulfhydryls were found to be decreased (p < 0.01), whereas plasma lipid peroxides were found to be increased (p < 0.05), in acute exacerbations of asthma. No significant differences were found in plasma glutathione peroxidase, protein carbonyls, and total nitrates and nitrites, red cell antioxidative enzyme activities, superoxide anion release from leukocytes, and total blood glutathione between the two groups (p > 0.05). Our observations suggest that acute exacerbations of asthma are associated with increased oxidative stress that is evident from some of the parameters in the plasma. Failure to observe simultaneous changes in all parameters of oxidative stress may be due to the possibility of their responses being dissociated in time or compensatory changes occurring in some of these.

The secondary alcohol and aglycone metabolites of doxorubicin alter metabolism of human erythrocytes.

Anthracyclines, a class of antitumor drugs widely used for the treatment of solid and hematological malignancies, cause a cumulative dose-dependent cardiac toxicity whose biochemical basis is unclear. Recent studies of the role of the metabolites of anthracyclines, i.e., the alcohol metabolite doxorubicinol and aglycone metabolites, have suggested new hypotheses about the mechanisms of anthracycline cardiotoxicity. In the present study, human red blood cells were used as a cell model. Exposure (1 h at 37 C) of intact human red blood cells to doxorubicinol (40 M) and to aglycone derivatives of doxorubicin (40 M) induced, compared with untreated red cells: i) a ~2-fold stimulation of the pentose phosphate pathway (PPP) and ii) a marked inhibition of the red cell antioxidant enzymes, glutathione peroxidase (~20%) and superoxide dismutase (~60%). In contrast to doxorubicin-derived metabolites, doxorubicin itself induced a slighter PPP stimulation (~35%) and this metabolic event was not associated with any alteration in glutathione reductase, glutathione peroxidase, catalase or superoxide dismutase activity. Furthermore, the interaction of hemoglobin with doxorubicin and its metabolites induced a significant increase (~22%) in oxygen affinity compared with hemoglobin incubated without drugs. On the basis of the results obtained in the present study, a new hypothesis, involving doxorubicinol and aglycone metabolites, has been proposed to clarify the mechanisms responsible for the doxorubicin-induced red blood cell toxicity.

A double-masked, randomized control trial of iron supplementation in early infancy in healthy term breast-fed infants

ObjectivesTo test whether iron supplementation affects hematologic, biochemical, and developmental status in term breast-fed infants. Study designTerm breast-fed infants (n=77) were randomly selected to receive either 7.5 mg per day of elemental iron as ferrous sulfate or placebo from 1 to 6 months of age. Investigators and families were unaware of group assignment. Complete blood count and ferritin, red cell superoxide dismutase, catalase, plasma ferric reducing antioxidant power, and zinc and copper levels were analyzed at 1, 3.5, 6, and 12 months of age. Bayley mental and psychomotor developmental indexes (MDI and PDI) and visual acuity (with the use of Teller acuity cards) were assessed from 12 to 18 months of age. Analysis performed by analysis of variance and t tests was by intention to treat. ResultsIron supplementation resulted in higher hemoglobin and mean corpuscular volume at 6 months of age and significantly higher visual acuity and PDI at 13 months of age (100±12 vs 93±9 [±SD]). Treatment and placebo groups did not differ in anthropometric indexes, compliance, biochemical status, or demographic characteristics. ConclusionsIron supplementation of breast-fed infants appears safe and might have beneficial hematologic and developmental effects for some infants.

Effect of vitamin E on plasma malondialdehyde, antioxidant enzyme levels and the rates of wound closures during wound healing in normal and diabetic rats.

Vitamin E is composed of various subfamilies that include tocopherols and tocotrienols. These compounds have antioxidant properties but differ in structure, dietary source and potency. In this study we evaluated the efficacy of alpha-tocopherol as an antioxidant and its role in wound closure in normal and streptozotocin-induced diabetic rats. The healing of 6 cm linear incisions created on the back of each male Sprague-Dawley rat (250-300 g) was monitored by measuring the length of the wounds daily. The rats were divided into two categories; normal and streptozotocin-induced diabetic rats. For each category, the animals were further divided into two groups; those untreated and those receiving 200 mg/kg bodyweight alpha-tocopherols daily by oral gavage. All rats were fed standard food and water ad libitum. Blood samples were taken at 0, 5 and 10 days after the wounds were created for the determination of malondialdehyde levels and red cell superoxide dismutase, catalase and glutathione peroxidase activities. The results showed that alpha-tocopherol reduced plasma malondialdehyde levels, increased glutathione peroxidase activity and accelerated the rate of wound closure in treated rats.

Red blood cell antioxidant levels in Wuchereria bancrofti infection

The elimination of microfilariae of Wuchereria bancrofti is probably mediated by free radicals. Red cell catalase (C), glutathione peroxidase (GPX), and superoxide dismutase (SOD) activity levels were measured as an indirect method of assessing blood oxidant status in 29 asymptomatic microfilaraemics, 29 “endemic normals”, and 29 controls living in a non-endemic area. Changes in the activity of these enzymes were also compared over a one month period in 22 asymptomatic microfilaraemics randomised to receive either single dose or 14 day treatment with diethyl carbamazine citrate (DEC). Red cell GPX activity levels were significantly higher in “endemic normals” when compared to mf positive cases and non-endemic controls. An early and significant increase in GPX activity (on days 3, 7 and 14 compared to pretreatment levels, p<0.01) was observed after DEC in both treatment groups. Increases in the activity of catalase and SOD became significant only on days 14 and 30 respectively. The percentage reduction in microfilaraemia correlated significantly with the percentage increase in GPX activity levels ( R 2=0.58, p=0.6×10 −5 ). Our results may suggest a role for GPX related oxidant species in the elimination of microfilariae.

Oxidative stress in pediatric nephrotic syndrome

Background: Nephrotic syndrome (NS) is a stressful condition for children where oxidative damage would also influence the response of these patients to therapy. Methods: The present study was conducted in children with nephrotic syndrome during relapse and remission and in 10 age- and sex-matched healthy volunteers. Red cell glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) concentrations as well as plasma ceruloplasmin (CP) and vitamin E concentrations were analyzed in controls and in patients. Results: Erythrocyte superoxide dismutase concentrations were significantly increased in both the groups when compared to controls. Erythrocyte glutathione significantly decreased in nephrotic syndrome in remission along with plasma vitamin E concentrations in both the groups. A significant increase in plasma ceruloplasmin was observed in cases in remission. However, no significant change was observed in the concentrations of erythrocyte malondialdehyde. Conclusion: Thus, antioxidant concentrations change considerably, indicating a compensatory mechanism to cope up with increased pro-oxidant status in such cases.

Ascorbic Acid Therapy in Lead Exposed Jewellery Workers of Bangladesh

A total of 32 male jewellery workers who had been exposed to the fumes and dust of lead for the previous 10 to 25 years and 22 controls matched for age and economic status were compared with respect to lipid peroxidation, antioxidant levels and copper, zinc status in relation to lead toxicity. Effects of ascorbic acid on these parameters were also noted. Blood haemoglobin, serum copper, zinc and vitamin E, and red cell superoxide dismutase were found to be diminished, with no changes observed in red cell glutathione peroxidase and serum glutathione reductase. Lipid peroxidation product levels were very high. Ascorbic acid supplement, an antioxidant, could partially restore the serum copper and zinc levels and red cell superoxide dismutase, leading to a significant decrease in the mean blood lead concentra- tion of jewellery workers. Dietary supplementation with ascorbic acid can complement other efforts to prevent lead exposure and reduce lead toxicity.

Altered anti-oxidant status and increased lipid peroxidation in marasmic children.

Protein energy malnutrition (PEM) is a common pediatric health problem in developing countries. Although the clinical features of PEM are well known, its pathophysiology is still unclear. Free radicals have been implicated in pathogenesis of PEM. In the present study, oxidant/anti-oxidant status in marasmus was investigated. Red cell glutathione, glutathione peroxidase and superoxide dismutase and their related cofactors, serum selenium and copper, were studied in marasmic and control children. Serum lipid peroxidation was also evaluated to assess oxidative stress. The red cell glutathione levels and glutathione peroxidase activities were found to be significantly lower in the marasmic children than in the controls. Red cell superoxide dismutase (SOD) activity was not different between two groups. Serum selenium and copper concentrations were significantly lower in the marasmic children than in the control subjects. The malondialdehyde concentration, which is an index of lipid peroxidation, was significantly higher in the marasmic group compared with the controls. The anti-oxidant defense system was affected in marasmic children. Reduced anti-oxidant status and increased oxidative stress occurs in marasmic children.

Influence of puberty on endothelial dysfunction and oxidative stress in young patients with type 1 diabetes.

To examine the influence of puberty on endothelial dysfunction and oxidative stress in children and young people with type 1 diabetes. There were 51 young patients with type 1 diabetes, including 12 prepubertal children, 16 adolescents, and 23 young adults who had no clinical diabetic angiopathy, studied; none had microalbuminuria. The three groups were matched for glycemic control, and systolic and diastolic blood pressures and cholesterol levels were not significantly different between the groups. Endothelium-dependent vasodilatation was assessed by laser Doppler flowmetry after iontophoresis of acetylcholine (ACh) to the skin of the dorsum of the right foot. Soluble E-selectin, intercellular cell adhesion molecule-1 (ICAM-1), von Willebrand factor (vWF), plasma thiol (PSH), red cell glutathione (GSH), and red cell superoxide dismutase (SOD) were measured in blood samples obtained in the early morning. Skin vascular responses to ACh were significantly reduced in the young adult group compared with the prepubertal group (P < 0.05, analysis of variance). The levels of soluble ICAM-1 and E-selectin were significantly higher in the adolescent group compared with the young adult group: 338 (267-415) and 89 (64-106) ng/ml (median [interquartile range]), respectively, versus 255 (222-284) and 58 (54-71) ng/ml (P < 0.01 and P < 0.005, Mann-Whitney U test). SOD levels were significantly higher in the prepubertal group at 250 (238-282) micro/ml, when compared with the adolescent, 217 (171-249) micro/ml (P < 0.04), and young adult, 217 (157-244) micro/ml (P < 0.02), groups. GSH tended to be lower in the adolescent group, 1,192 (1,047-1,367) micromol/l, when compared with the young adults, 1,286 (1,145-1,525) pmol/l, and levels of vWF tended to be higher in the adolescent group, but these failed to reach statistical significance (both P = 0.09). PSH was not different between the three groups. These results suggest that puberty modulates endothelial function and antioxidant mechanisms in childhood diabetes, which may have implications for therapy and intervention.

Reduced erythrocyte deformability related to activated lipid peroxidation during the early postburn period

The role of lipid peroxidation in reduced red cell deformability has been examined after thermal injury of rats (full skin thickness over 15–20 per cent of total body surface). An increased concentration of erythrocyte malonyldialdehyde (MDA) and blood thiobarbituric acid (TBA) reactive product levels during the first 3 days after thermal trauma was established. There was a remarkable decrease in red cell superoxide dismutase (SOD) activity after burns and an increase in glucose-6-phosphate dehydrogenase (G-6-PD) on day 3 postburn. The deformability of erythrocytes was diminished significantly during the first 3 days after burns. There was a significant negative correlation between the deformability and the amount of MDA accumulated in erythrocytes (r= −0.92). Both the accumulation of MDA and the reduction of SOD activity in erythrocytes were suppressed by alpha-tocopherol treatment, which also prevented the decrease in erythrocyte deformability. These results suggest that the activation of the peroxidative process is a possible mechanism for the decreased deformability of erythrocytes during the early stage after thermal injury.

Effect of antibodies to red cell superoxide dismutase on its activity in the blood of patients with rheumatoid arthritis

A relationship is revealed between the level of antibodies to superoxide dismutase and the activity, course, and form of a disease. The production of antibodies to red cell superoxide dismutase increases as the pathological process progresses. By reducing the resistance of erythrocyte membranes to reactive oxygen species, antibodies to red cell superoxide dismutase promote the development of anemia in patients with rheumatoid arthritis. The results indicate that inhibition of the active center of this enzyme by specific immunoglobulins is one of the causes of reduced activity of red cell superoxide dismutase or the lack of an appreciable increase in its activity during hyperproduction of reactive oxygen species.

Superoxide Anion Release by Polymorphonuclear Leukocytes in Whole Blood of Newborns and Mothers during the Peripartal Period

Superoxide anion (.O2-) production was investigated in whole blood of mothers in the peripartal period and in neonates. Blood samples from 14 mothers undergoing vaginal delivery (VD) were tested at the beginning of labor, during labor, after delivery, and 4 d after delivery. Nine mothers undergoing elective cesarean section (ECS) were tested before anesthesia, after extraction of the fetus, and 4 d later. Seventy-two healthy, full-term newborn infants were examined at birth and on the fourth day of life. Red cell glutathione peroxidase, catalase, glutathione reductase, and superoxide dismutase activities were also measured at birth and on the fourth day of life in 26 of the 72 neonates. Higher .O2- levels were detected in mothers undergoing VD compared with ECS (p < 0.05). A significant decrease was detected in zymosan-stimulated .O2- production between cord and fourth-day blood samples in both VD- and ECS-delivered infants (p < 0.01). Zymosan-stimulated samples showed higher values after VD than ECS, both in cord blood (p < 0.004) and on the fourth day of life (p < 0.006). A positive correlation was found between .O2- release in zymosan-stimulated cord blood and that found in the mothers at the beginning of labor (r = 0.654; p < 0.01), during labor (r = 0.721; p = 0.008), and after delivery (r = 0.832; p = 0.0008). A positive correlation was also found between .O2- release and glutathione peroxidase on the fourth day (r = 0.709, p = 0.014).(ABSTRACT TRUNCATED AT 250 WORDS)