Newborn Erythrocytes Research Articles

Morphological Changes in Erythrocytes of Newborns after Perinatal Hypoxia

Morphological Changes in Erythrocytes of Newborns after Perinatal Hypoxia

Reference Values for Quantitative Testing of G6PD Deficiency in Newborns from the Republic of North Macedonia

Glucose-6-phosphate dehydrogenase is a key regulatory enzyme in the pentose-phosphate cycle that participates in the formation of reduced equivalents to maintain the cellular redox status. The G6PD enzyme activity is crucial in protecting cells from oxidative stress. Deficit of the glucose-6-phosphate dehydrogenase (G6PD) has been recognized as the most common inherited enzymopathy worldwide. In the Republic of North Macedonia (RNM), the deficit of glucose-6-phosphate dehydrogenase has been infrequently investigated. Moreover, no reports exist on quantitative testing of G6PD in newborns from the RNM. SCOPE: The aim of our study was to determine the reference values for the level of G6PD in erythrocytes of newborns from the Republic of North Macedonia. For this purpose, eighty-two healthy newborns were selected and tested for G6PD by the quantitative spectrophotometric method. RESULTS: The mean ± SD of the G6PD quantitative value in the examined group was 229.12 ± 24.2 mU/109Er ranging from a minimum of 191.7 to a maximum of 288, and a median of 228.0 mU/109Er, values that were lower than the preset reference values of the diagnostic test in use. CONCLUSION: We speculated that by establishing a specific reference value (range) for the target population and for the appropriate diagnostic test, we would gain increased sensitivity of the test. This would help optimize detection of G6PD deficient newborns, mild-variant hemizygotes and female heterozygotes for the deficiency.

EFFECTIVENESS OF OZONE THERAPY IN REHABILITATION OF NEWBORNS AFTER INTRAUTERINE HYPOXIA

Aim . To estimate efficiency of inhalation ozone therapy at rehabilitation of newborns who had suffered from intrauterine hypoxia. Materials and methods. The complex clinical laboratory research of the antioxidant status of 150 newborns was conducted. The control group included 30 almost healthy newborns whose mothers had no somatic diseases and were characterized by physiological gestation course. The group of comparison was presented by 45 newborns whose mothers had secondary chronic placental insufficiency and received drug treatment without the course of ozone therapy. 75 newborns whose mothers received ozone-air mixture inhalations along with traditional therapy entered into clinical group. The erythrocytes of newborns’ dark blood taken right after the birth were chosen as a material for the research. The activity of superoxide dismutases (SOD), catalases, glutathione peroxidases (GPO), glutathione reductase (GSR), glucose-6-phosphate dehydrogenase (G6PD), as well as concentration of the restored glutathione (GSH) were assayed. Results. It was established that the compensatory and adaptive reactions providing elimination of the reasons of oxidizing stress development due to the stimulating influence of ozone on activity of antioxidant protection enzymes were formed in newborns of clinical group. Conclusion. In this regard, the offered scheme of the ozone therapy can be recommended for a complex rehabilitation of pregnant women with the chronic secondary placental insufficiency against the background of cardiovascular diseases.

Enzyme Activities in Erythrocytes of Term and Preterm Newborns

The decrease of erythrocyte antioxidant enzyme activity should be considered as a possible cause of hemolysis when there is no evidence of an immune-mediated hemolytic anemia, no consumptive red blood cell disorder, no morphologic or laboratory data to suggest a problem of the red cell membrane, and no evidence of a quantitative or qualitative defect in hemoglobin synthesis. Glutatione has a pilot role in orchestrating the redox balance when there is an excess reactive oxygen species production or defective antioxidant defenses that may have deleterious consequences in various perinatal diseases. Neonatal erythrocytes are a target of extracellular free radicals and in the same time generators of free radicals through Fenton reaction. The complex mechanism underlying the increased oxidative stress susceptibility of neonatal erythrocytes requires further investigation.

Fatty acid status and antioxidant defense system in mothers and their newborns after salmon intake during late pregnancy

ObjectiveThe aim of the present study was to assess the maternal and newborn status of erythrocyte fatty acids and the antioxidant defense system after the intake of two portions of salmon per week during late pregnancy. MethodsPregnant women (N = 123) were randomly assigned to continue their habitual diet, which was low in oily fish (control group, n = 61) or to consume two 150-g salmon portions per week (salmon group, n = 62) beginning at 20 wk of gestation and lasting until delivery. Fatty acids, selenium, and glutathione concentrations and antioxidant defense enzyme activities were measured in maternal erythrocytes at 20, 34, and 38 wk of pregnancy, and in cord erythrocytes collected at birth. Plasma concentrations of antioxidant molecules were measured. ResultsCompared with the control group, consuming salmon had little effect on erythrocyte fatty acids in either mothers or newborns. Components of the antioxidant defense system did not differ between groups. Glutathione peroxidase activity and the concentrations of tocopherols, retinol, and coenzyme Q10 were significantly lower in cord blood compared with maternal blood at week 38 in both groups. ConclusionMaternal and newborn erythrocyte fatty acids are not strongly affected by the intake of two portions of salmon per week during the second half of pregnancy, although erythrocyte docosahexaenoic acid might be increased in newborns. Maternal and newborn antioxidant defense systems are not impaired by intake of salmon from 20 wk gestation.

LPO-Antioxidant Defense System in Newborns and Women Drinking Small Amounts of Alcohol During Pregnancy.

We studied the effects of consumption of low-alcohol drinks (no more than 2 doses) during pregnancy on the state of LPO-antioxidant defense system and glutathione level in the blood serum and erythrocytes of pregnant women and newborns. It was found that even single alcohol intake was followed by the development of oxidative stress in women and newborns. In pregnant women, the decrease in reduced glutathione content and glutathione reductase activity associated with increased level of oxidized glutathione and glutathione transferase activity were typical changes. In newborns, the decrease in reduced glutathione concentration was accompanied by a decrease in glutathione reductase, glutathione transferase, and glutathione peroxidase activities. It should be emphasized that even small alcohol doses produce delayed negative effects on metabolism of the mother and newborns.

5-Methyltetrahydrofolate and thiamine diphosphate in cord-blood erythrocytes of preterm versus term newborns

A low folate or low thiamine status may be associated with the risk of preterm delivery, small for gestational age (SGA) offspring and adverse pregnancy outcomes. 5-Methyltetrahydrofolate (5MTHF) and thiamine diphosphate (TDP) were measured directly in cord-blood erythrocytes (CBEs) of early preterm (n=26; <32 weeks gestational age; including 50% multiple births), late preterm (n=38; 32 to <37 weeks; including 24% multiple births) and term newborns (n=60, 37-42 weeks) via high-performance liquid chromatography and fluorescence detection. Associations between 5MTHF and TDP with gestational age, newborn anthropometrics (birth weight, newborn's length and head circumference) and risk of being SGA were explored. Group comparison as well as multivariate linear regression analysis of cord-blood vitamins revealed that 5MTHF was significantly lower in late preterms compared with terms but did not differ between singletons and multiples. TDP tended to be higher in preterms than in terms and lower in multiples than in singletons in both early and late preterms. Multivariate analysis on birth outcomes showed that 5MTHF was significantly positively associated with gestational age, birth weight and newborn's length. 5MTHF, increasing gestational age and parity were associated with a significantly reduced risk for being SGA, while TDP, multiple births and gender were not associated with the risk for being SGA. Higher CBE concentrations of 5MTHF were associated with improved birth outcomes. Lower TDP concentrations were observed in multiple births. Future studies evaluating cord-blood vitamin concentrations and their associations with birth outcomes should additionally include dietary intakes and maternal blood concentrations at different stages of pregnancy.

Antioxidant enzyme activities in erythrocytes of healthy pregnant women, preeclamptic women and newborns

Preeclampsia is a pregnancy-specific syndrome of unknown etiology and represents multisystem disorder. It is characterized by the increased blood pressure, proteinuria, and edema. Preeclampsia is a great risk for both mother and fetus. Disturbances of the balance between the production of reactive oxygen species antioxidants status is considered to be one of the causes of various pathological conditions of the reproductive system, including preeclampsia. The main objective of this study is to determine the activities of superoxide-dismutase and catalase in peripheral blood erythrocytes of the pregnant women with preeclampsia and healthy pregnant women before delivery and umbilical cord blood erythrocytes of their babies immediately after the delivery. The results showed that the activity of superoxide dismutase in erythrocytes were statistically significantly lower in the group of patients with preeclampsia than in healthy pregnant women, as in the group of their babies compared to the babies of healthy pregnant women. Similarly, catalase activity was significantly lower in women with preeclampsia compared to the controls, as well as in erythrocytes of their babies compared to babies of healthy mothers. An observed difference in the antioxidant enzyme activities suggests a putative association between preeclampsia and decreased antioxidant status. Since the direct application of antioxidants did not give expected results of the data presented indicate the opportunity for the prevention of preeclampsia and alleviation of symptoms by dietary measures and life style changes in the population of pregnant women and women of childbearing age, directy targeting the enzymatic antioxidant system.

Prenatal screening of thalassemia in 7210 samples of neonatal cord blood and G6PD deficiency

Objective To explore the incidence of newborn hemoglobinopathy and erythrocyte enzyme disorders after regular prenatal visits and genetic consulting. Methods The band on hemoglobin electrophoresis and the G6PD level were detected in 7210 samples of umbilical cord blood by hemoglobin electrophoresis and G6PD ratio method. Results Of 7210 samples,the detection rate of G6PD deficiency was 4.38％. The detected rates of α -thalassemia with a/a mutation and standard α-thalassemia were 2.50％and 5.89％. The incidence of the three disorders in 2009 was decreased by 0.18％,0.08％,and 0.44％,as compared with 2008. Conclusions The probability of the incidence of the disorders reduces in the confirmed low-risk neonates after regular prenatal visits and consulting,as compared with the predictive probability. Prenatal visits and genetic consulting play an important role in preventing the birth rate of neonates with severe thalassemia. Key words: Hemoglobin electrophoresis; Glucose-6-phosphate dehydrogenase; Umbilical cord blood; Prenatal visits; Genetic consulting

Structural properties and antioxidant system activity of the newborn erythrocytes in oxidative stress of different intensities

Structural properties and antioxidant system activity of the newborn erythrocytes in oxidative stress of different intensities

Changes in Erythrocyte Glutathione and Plasma Membrane Calcium Pump in Preterm Newborns Treated Antenatally with MgSO4

Background: Magnesium is required for the proper activity of many metabolic pathways in every cell type. Mg deficiency gives rise to preterm birth and low body weight that are associated with pathological circumstances, including disturbed ions homeostasis and insufficient antioxidant protection. Antenatal MgSO₄ treatment has been reported to exhibit a protective effect on the developing fetus; however, the molecular mechanism of this protection remains not fully understood. Objectives: Since Mg ions very rapid cross the placenta, our study tested the hypothesis whether prenatal exposure to MgSO₄ may modify the expression and activity of erythrocyte plasma membrane calcium pump (PMCA), and total erythrocyte glutathione (GSH) concentration in preterm newborns. Methods: Immunocharacteristics of erythrocyte PMCA in control and MgSO₄-treated newborns were done using general and isoform-specific antibodies. The hydrolytic activity of PMCA was determined with and without calmodulin. Total GSH erythrocyte levels were analyzed by a quantitative assay using Ellman reagent. All assays were done after delivery and 24 h later. Results: Significant differences were present in PMCA amount, isoform composition, basal activity and sensitivity for stimulation by calmodulin in both groups of neonates. The total GSH content altered during examined time, but only in the control group. Conclusions: Prenatal treatment with MgSO₄ may exert a significant influence on calcium homeostasis and nonenzymatic antioxidant reserve in the erythrocytes of preterm newborns.

Prenatal MgSO 4 treatment modifies the erythrocyte band 3 in preterm neonates

Magnesium sulphate that is widely used to prevent preterm labour or treatment for imminent eclampsia is also suggested to decrease a cerebral palsy in preterm newborns. However, the molecular mechanism of MgSO 4 protection in fetus remains unknown. Since Mg 2+ very rapidly crosses the placenta, we assayed whether it may exert an effect on newborn erythrocytes, particularly on anion exchange band 3. The study groups consisted of preterm neonates born from mothers who received prenatally magnesium sulphate and a control group, without prenatal Mg 2+ administration. We compared the selected erythrocyte parameters including ATP concentration, membrane lipids peroxidation, the band 3 amount and its phosphotyrosine level, assayed after delivery and 24 h later. At birth, ATP concentration was higher in control newborns and decreased after 24 h, reaching the level found in the MgSO 4-treated group. Band 3 and P-Tyr amounts were unchanged in MgSO 4-treated newborns during examined period. In the control group, the lower Mg concentration after delivery correlated with the lowered band 3 phosphorylation. We have also observed enlarged TBARS content in control membranes. Our results demonstrate that prenatal administration of magnesium sulphate significantly altered some erythrocyte parameters. These data suggest that MgSO 4 may modify the erythrocytes metabolism in preterm newborns. Since band 3 exhibits the same structural and functional activities as in the brain, the elucidation of MgSO 4 influence is of special importance.

Oxidative stress and autologous immunoglobulin G binding to band 3 dimers in newborn erythrocytes

Since birth-induced oxidative stress (OS) results in the removal of erythrocytes from the blood stream, we studied the binding of autologous IgG to erythrocyte band 3 dimers (the 170-kDa band, which marks the erythrocytes for removal) in preterm and term newborns and in adults. The 170-kDa band was present in as much as 74% of preterm, in 21% of term newborns, and in 10% of adults. During erythrocyte ageing “in vitro” (0, 24, and 48 h aerobic incubation), the appearance of the band occurred much faster with erythrocytes from newborns (particularly preterm) than with those from adults. When the blots for the 170-kDa band were quantified by scanning densitometry, it was seen that the 0 time values were significantly higher in preterm compared to term and adult values. After aerobic incubation a progressive increase in the optical density was observed in each group and the densities were higher in preterm than in the other groups. The course of iron release during the various incubations was analogous to that of the 170-kDa band blots, and significant correlations were found at 0 and 48 h. Methemoglobin formation roughly paralleled iron release. Esterified F 2-isoprostanes (markers of OS) and O 2 − production in the nonincubated (0 time) erythrocytes were much higher in newborn (preterm and term) than in adult erythrocytes. Plasma free F 2-isoprostanes were significantly higher in preterms than in terms and in terms than in adults. Plasma non-protein-bound iron (NPBI) was higher in preterm than in term newborns and not detectable in adults. In conclusion dimers of band 3 with autologous IgG are found under conditions in which OS can be detected in erythrocytes or in plasma: namely in newborns or in aged erythrocytes.

162 Effect of Maternal Magnesium Sulfate Administration on Band 3 Phosphorylation in Erythrocytes of Preterm Newborns

Magnesium sulfate is widely used as treatment for imminent eclampsia or to prevent preterm labor. Its use for the purpose of neuroprotection in preemies is controversial. We evaluated whether they might also have an effect on function of the erythrocytes. The aim of the presented study was to compare the selected erythrocyte membrane parameters including ATP concentration, the band 3 (prominent transmembrane protein of erythrocytes)amount, and phosphotyrosine content in erythrocyte membranes of preterm newborn whose mothers were treated or untreated with magnesium sulfate. The study group consist of preterm neonates (n-15) prenatally exposed to magnesium sulphate. Mean GA was 29,1 weeks (range 26–34) and mean birth weight was 1331g (range 650-1950). Control group included 20 infants (without prenatal Mg2+ administration). Mean gestational age was 30,78 weeks (range 26–34) and mean birth weight was 1392g (range 800-1800). In both groups, blood from umbilical cord vein was collected with citrate and than erythrocyte ghost were prepared. After birth, ATP concentration in erythrocytes of treated group was lower by 24% in relation to the control one (1.27± 0.44 mmol/g Hb) but after 24h we observed similar level in both groups (1.02±0.12 vs 1.09±0.19). The band 3 amount determined using the specific antibody was significantly decreased (50%) in magnesium-treated newborns during the studied period. However, after birth we observed the same phosphotyrosine level in both groups. P-Tyr amount was unchanged in magnesium-treated newborns after 24h of life, whereas increased by 20% in the control group. The presence of MgATP complex is necessary for a proper functioning of protein kinases. The administration of magnesium sulfate could intensify the phosphorylation of band 3 by tyrosine kinases thus increasing the glycolysis in erythrocytes. Supported by the grants No. 5P05E 09224 from the State Committee for Scientific Research, and No. 503 from the MU of Lodz.

Effect of maternal manganese blood levels on erythrocyte calcium-pump activity in newborns

Manganese (Mn) is widely distributed in the biosphere but occurs in only trace amounts in animal tissues. Although Mn deficiency and toxicity both have pathological consequences, the underlying biochemical lesions have not been well defined. In vitro studies suggest that transport proteins are affected by Mn, lead (Pb), and selenium (Se). Among these transport proteins, the calmodulin-regulated calcium pump (Ca 2+Mg 2+ATPase) could be inhibited by Mn. In order to understand Mn biochemical pathways, we examined the relationships between Mn blood levels and red blood cell Ca-pump activity among 248 mothers and newborns, environmentally exposed to Mn, Pb, and Se. Population and methods 248 mother–newborn pairs were recruited at Robert Debré University Hospital (Paris). Blood Mn and Pb concentrations were measured by absorption spectrophotometry. Se was measured by fluorometric method. Red blood cell membrane suspensions were obtained for Ca-pump activity measurements. Linear and quadratic regression models and Pearson correlation were performed. Results A non-linear parabolic relationship between maternal Mn blood levels and newborn Ca-pump activity was discovered from the analysis of the observed data. The peak level of maternal Mn that corresponded to a maximal activity of the newborn Ca-pump was estimated at 23.9 μg/l with a 95% confidence interval of 17.6 to 32.4 μg/l. An inhibition of this enzyme was observed at low and high levels of maternal Mn. The relationships between the newborn Ca-pump activity and maternal Se and Pb levels became non-significant after adjustment on all the co-factors included in the final model. Conclusion Maternal environmental exposure to Mn, as reflected by maternal blood levels of this metal, is associated with a reduced activity of newborn erythrocyte Ca-pump in a non-linear pattern. Mn levels between 17.6 and 32.4 μg/l in maternal blood probably correspond to the optimal physiological concentration for the metabolism of this enzyme in newborns.

RELATIONSHIPS BETWEEN ERYTHROCYTE CALCIUM-PUMP ACTIVITY AND MANGANESE LEVELS IN MOTHERS AND NEWBORNS

ISEE-365 Introduction: Manganese (Mn) is widely distributed in the biosphere but occurs in only trace amounts in animal tissues. Although Mn deficiency and toxicity both have pathological consequences, the underlying biochemical lesions have not been well defined. In vitro studies suggest that transport proteins are affected by Mn, lead (Pb) and selenium (Se). Among these transport proteins, the calmodulin-regulated calcium pump (Ca2+Mg2+ATPase) could be inhibited by Mn. This inhibition is one of the major mechanisms of Mn neurotoxicity. In order to better understand Mn toxicity in humans, we examined the relationships between Mn blood levels and red blood cell Ca-pump activity among 248 mothers environmentally exposed to Mn, Pb and Se, and their newborns. Population and Methods: 248 mother-newborn couples were recruited at Robert Debré University Hospital (Paris). All mothers gave informed consent. Information regarding obstetrical history was obtained from medical records. Mn and Pb concentrations were measured by absorption spectrophotometry. Se was measured by fluorometric method. Red blood cell membrane suspensions were obtained as described by Campagna et al. (2000). Linear and quadratic regression models and Pearson correlations were performed. Results: In contrast to Pb and Se, Mn blood levels in newborns were significantly higher than those in their mothers (41.1±15.2 versus 22.7±14.2 microgr/l, paired t test: p<0.0001). Positive correlations were also noted between maternal and neonatal blood levels of Mn (r=0.28; p<0.0001), Pb (r=0.46; p<0.0001) and Se (r=0.34; p<0.0001). A non-linear parabolic relationship between maternal Mn blood levels and newborn Ca-pump activity was discovered from the analysis of the observed data. The peak level of maternal Mn that corresponded to a maximal activity of the newborn Ca-pump was estimated at 23.9 microgr/l with a 95% confidence interval of 17.6 to 32.4 microgr/l. An inhibition of this enzyme was observed at low and high levels of maternal Mn. The relationships between the newborn Ca-pump activity and maternal Mn remained significant after adjustments on maternal Se and Pb levels and on all the co-factors included in the final model. Conclusions: Maternal environmental exposure to Mn, as reflected by maternal blood levels of this metal, is associated with a reduced activity of newborn erythrocyte Ca-pump in a non-linear pattern. Mn levels between 17.6 and 32.4 microgr/l in maternal blood probably correspond to the optimal physiological concentration for the metabolism of this enzyme in newborns.

Iron release, superoxide production and binding of autologous IgG to band 3 dimers in newborn and adult erythrocytes exposed to hypoxia and hypoxia-reoxygenation

Iron is released in a desferrioxamine (DFO)-chelatable form when erythrocytes are challenged by an oxidative stress. The release is increased when an accelerated removal of erythrocytes occurs such as in perinatal period, in which iron release is greater in hypoxic than in non-hypoxic newborns. This suggests that an hypoxic environment at birth promotes iron release. To test this possibility, iron release in a model of hypoxia, hypoxia-reoxygenation and normoxia was studied in newborn and adult erythrocytes. In newborn erythrocytes, hypoxia induced a much greater iron release compared to an equal period of normoxia. In adult erythrocytes, hypoxia also induced a greater iron release as compared to normoxia, but it was much lower than that seen with newborn erythrocytes. Methemoglobin (MetHb) formation roughly paralleled iron release. The phenylhydrazine-promoted superoxide anion (O 2 − ) production was greater with normoxic but lower with hypoxic erythrocytes from newborns as compared to that from adults. This discrepancy between iron release and O 2 − production may be explained by the shift towards MetHb in hemoglobin autoxidation. Iron diffusion out of the erythrocytes was much higher with hypoxic erythrocytes from newborns as compared to that from adults. Also the binding of autologous IgG to band 3 dimers (AIgGB) is much greater with hypoxic erythrocytes from newborns as compared to that from adults, suggesting that the level of iron release is related to the extent of band 3 clustering and that hypoxia accelerates removal of erythrocytes from bloodstream in in vivo condition.

Iron release, superoxide production and binding of autologous IgG to band 3 dimers in newborn and adult erythrocytes exposed to hypoxia and hypoxia-reoxygenation.

Iron is released in a desferrioxamine (DFO)-chelatable form when erythrocytes are challenged by an oxidative stress. The release is increased when an accelerated removal of erythrocytes occurs such as in perinatal period, in which iron release is greater in hypoxic than in non-hypoxic newborns. This suggests that an hypoxic environment at birth promotes iron release. To test this possibility, iron release in a model of hypoxia, hypoxia-reoxygenation and normoxia was studied in newborn and adult erythrocytes. In newborn erythrocytes, hypoxia induced a much greater iron release compared to an equal period of normoxia. In adult erythrocytes, hypoxia also induced a greater iron release as compared to normoxia, but it was much lower than that seen with newborn erythrocytes. Methemoglobin (MetHb) formation roughly paralleled iron release. The phenylhydrazine-promoted superoxide anion (O(2)?(-)) production was greater with normoxic but lower with hypoxic erythrocytes from newborns as compared to that from adults. This discrepancy between iron release and O(2)?(-) production may be explained by the shift towards MetHb in hemoglobin autoxidation. Iron diffusion out of the erythrocytes was much higher with hypoxic erythrocytes from newborns as compared to that from adults. Also the binding of autologous IgG to band 3 dimers (AIgGB) is much greater with hypoxic erythrocytes from newborns as compared to that from adults, suggesting that the level of iron release is related to the extent of band 3 clustering and that hypoxia accelerates removal of erythrocytes from bloodstream in in vivo condition.

Glutathione Recycling and Antioxidant Enzyme Activities in Erythrocytes of Term and Preterm Newborns at Birth

We previously demonstrated a high susceptibility of neonatal red blood cells (RBC) to oxidative stress at birth. The aim of this study was to compare the RBC antioxidant capacity and redox cycle enzyme activities as well as glutathione (GSH) recycling in full-term and preterm infants at birth and in normal adults. GSH and GSH disulfide (GSSG) concentrations, GSH/GSSG ratio, and the activities of glucose-6-phosphate dehydrogenase (G-6-PDH), GSH peroxidase, GSH reductase (GR), catalase (CAT), superoxide dismutase (SOD), and hexokinase (HK) were measured in RBC of 25 healthy adults and 56 newborns (23 term, 33 preterm) at birth. The GSH recycling was measured in adult and newborn RBC exposed to oxidative stress (1 mM tert-butylhydroperoxide). The RBC of term and preterm babies showed higher GSH, GSSG, G-6-PDH, GR, and HK levels/activities and lower GSH/GSSG ratios and higher GSH-recycling rates than those of adults. In preterm babies significant correlations were found between G-6-PDH and CAT, GSH, GSH/GSSG ratio, and GSSG (r = –0.67, r = 0.71, r = –0.66, p < 0.01; r = 0.71, p < 0.05, respectively). In term newborns, statistically significant correlations were observed between G-6-PDH and CAT, SOD, and GSH (r = –0.65, r = –0.65, r = –0.69, p < 0.01, respectively). The results indicate the central role of the G-6-PDH activity in antioxidant defenses. We speculate that preterm babies have prompter involvement of antioxidant defenses than term babies.

Variability in the rate of 6-mercaptopurine methylation in the erythrocytes, liver and kidney in an Italian population.

The polymorphism of erythrocyte thiopurine methyltransferase (TPMT) is genetically regulated as an autosomal codominant trait, and so should be congenital. We tested this hypothesis by measuring TPMT activity in erythrocyte preparations from adults and newborns and observed polymorphic distribution of TPMT activity in the adult and newborn erythrocytes. The activity of TPMT was higher in red cells from the newborns than adults. The frequency distribution of TPMT activity was also investigated in the liver and kidney. In the kidney, TPMT activity fell into two subgroups, whereas in the liver the distribution pattern was more complex. The activity of TPMT in erythrocytes and liver from the same subject was correlated, but the values of only half the cases fell within the 95% confidence limits, suggesting that the control of hepatic and/or erythrocyte TPMT is multifactorial.