Newborn Plasma Research Articles

Functional characterization of an endogenous digitalis-like factor in human newborn plasma. Effects on rat (Na+/K+)-ATPase isoforms and on binding to placenta.

Functional characterization of an endogenous digitalis-like factor in human newborn plasma. Effects on rat (Na+/K+)-ATPase isoforms and on binding to placenta.

The effects of maternal cigarette smoke exposure on somatic mutant frequencies at the hprt locus in healthy newborns

We utilized the hprt T-cell cloning assay to prospectively determined the somatic mutant frequency at the hprt locus of fetal T-lymphocytes exposed in utero to maternal active and passive cigarette smoke. In addition, a maternal questionnaire was administered to evaluate a number of social and medical parameters that may effect hprt mutant frequency. Newborn cord blood plasma cotinine levels were determined on all subjects to compare in utero tobacco metabolite levels with maternal smoking histories. A total of 63 newborns were enrolled and placed into four groups: Group I ( n=21), newborns whose mothers had no history of active or passive cigarette exposure during the pregnancy; Group II ( n=12), newborns whose mothers actively smoked cigarettes throughout the pregnancy; Group III ( n=8), newborns whose mothers actively smoked cigarettes during first trimester only; and Group IV ( n=22), newborns whose mothers were exposed only to passive cigarette smoke. Our analysis showed no statistically significant difference in hprt mutation frequency between any of the four groups. A significant increase in plasma cord blood cotinine was detected in Group II, newborns whose mothers were active cigarette smokers throughout the pregnancy. Our data indicate that exposure to active and passive maternal cigarette smoke in utero does not result in a significant increase in somatic mutant frequency as determined by the hprt T-cell cloning assay.

Fibronectin Enhances In Vitro Lipopolysaccharide Priming of Polymorphonuclear Leukocytes

AbstractWe investigated the role of humoral factors in lipopolysaccharide (LPS) priming of polymorphonuclear leukocytes (PMN) using cells isolated from adults and from neonates. Plasma from newborn infants had decreased priming activity of adult plasma when mixed with LPS in studies measuring oxidative radical production of PMN after stimulation with a formyl bacterial oligopeptide (fMLP). This marked difference was not caused by LPS binding protein (LBP) because the LBP concentration in newborn and adult plasma were similar (138.4 ± 12.9 U for adults, and 126.9 ± 12.1 U for neonates, P = .53). Therefore, we attempted to identify other plasma factors that may contribute to LPS priming of PMN. We identified an LPS priming factor for PMN that is present in plasma, heat stable (56°C for 30 minutes), enhanced by heparin, and concentrated in cold precipitates of plasma. Because these properties resemble those of plasma fibronectin, we assessed the role of fibronectin in LPS priming of PMN. Although fibronectin in phosphate-buffered saline (PBS) had little effect on LPS priming of PMN, fibronectin in combination with other plasma factors appeared to play a role in LPS priming of PMN because (1) removing fibronectin from adult plasma dramatically decreased LPS priming activity from plasma (P < .005), (2) addition of fibronectin to fibronectin-depleted plasma restored its LPS plasma priming activity (P < .05), and (3) neutralizing fibronectin with antibody decreased the LPS priming activity of plasma (60.3 ± 1.3 v 30.2 ± 2.2, P < .01). Thus, plasma fibronectin plays a role in LPS priming of PMN in the presence of other factors in plasma.

Newborn Plasma Demonstrates Lower Lipid Peroxide Production Compared to Adult Plasma During Photooxidative Stress. 1416

INTRODUCTION: We have shown that very-low-birth-weight (VLBW; BW≤1500 g) infants develop elevated plasma riboflavin (R; vitamin B2) to 50-fold cord concentrations during their first postnatal month due to dietary augmentation and immature renal function. Neonatal hyperbilirubinemia is usually treated with phototherapy. R is photoreactive and can peroxidize lipid membranes with photoexposure (PE), exposing VLBW infants to lipid peroxide (LP) related diseases such as ROP and BPD. Lipid emulsion (LE) is a standard component of VLBW infant parenteral nutrition and may provide a substrate for peroxidation. Our hypothesis was that neonatal plasma would produce more LP during photooxidative stress compared to adult plasma. METHODS: Blood was collected from 21 non-pregnant, non-smoking adult females and 14 AGA newborns at delivery. Plasma was isolated by centrifugation at 4000g × 5 minutes and R supplemented to 50(control), 500, and 5000 ng/mL. 9 adult and 7 infant samples were supplemented to LE of O (control), 0.2 and 0.6 Gm/dL. Samples were PE for 0, 2, 4 and 6 hours via an Ohmeda® high intensity fiberoptic pad. LP were determined using a spectrophotometric LP assay. Data were analyzed using ANOVA. RESULTS: Adult plasma developed higher LP compared to infants, p<0.001 (Figure). R, duration of PE and LE all independently increased LP, p<0.001. The highest LP values were measured using adult plasma with R=5000, IL=0.6 and 6 h of PE: 114±13.6 nmol/ml. CONCLUSIONS: From these data we conclude our hypothesis was false. Newborns demonstrated less LP production using this model. R, duration of PE and LE all independently increased LP production. We suggest that LP induced injury in newborns results from postnatal disease and environment rather than inherent predisposition to LP production at delivery.

Further evidence for an endogenous digitalis-like compound in newborn and adult plasma detected by anti-ouabain antiserum.

It is widely but not unanimously accepted that one or more endogenous digitalis-like factors (EDLF) circulate in human plasma. In this paper we provide confirmatory evidence that newborn plasma contains a factor with immunological and biological properties similar to ouabain and demonstrate that this factor may be present also in the adult. In fact, we obtained in newborn and adult plasma extracts, identical HPLC elution profiles of ouabain-like immunoreactivity and 86Rb erythrocyte uptake inhibitory activity with a major peak corresponding to the retention time of ouabain. The fact that immunoreactivity and biological digitalis-like activity in the peak are due to an identical substance is strongly supported by the correlation between RIA and 86Rb uptake inhibitory values observed in the purified fractions. Finally, the strong correlation between immunoreactivity observed in plasma samples after simple SepPak C18 extraction and after additional HPLC suggests that less purified samples may be assayed for screening purposes. However, for a more quantitative assessment, this simple extraction method needs a subsequent HPLC purification for eliminating an overestimation of values due to cross-reacting impurities.

Plasma and Urinary Soluble Thrombomodulin in Newborns with Respiratory Distress Syndrome and Chronic Lung Disease

Plasma and Urinary Soluble Thrombomodulin in Newborns with Respiratory Distress Syndrome and Chronic Lung Disease

Vitamin E and vitamin E-quinone levels in red blood cells and plasma of newborn infants and their mothers.

Vitamin E is a physiological antioxidant and protects cell membranes from oxidative damage. This study has determined whether vitamin E level in RBC of newborns has any relationship with its level in their mothers. We have also examined levels of vitamin E and vitamin E-quinone, an oxidized product of vitamin E, in paired samples of red blood cells (RBC) and plasma of newborns and their mothers. Blood was collected from 26 mothers and their full-term placental cords at delivery. Vitamin E and vitamin E-quinone levels were determined in RBC and plasma by HPLC. Newborn-plasma had significantly lower vitamin E levels compared with maternal-plasma both when expressed as nmole/ml (5.5+/-0.4 vs 26.1+/-1.1, p = 0.0001) or nmole/mumole total lipids (1.9+/-0.1 vs 2.6+/-0.1, p = 0.0001). Vitamin E level in the newborn-RBC was similar to that of maternal-RBC when expressed as nmole/ml packed cells (2.77+/-0.14 vs 2.95+/-0.13), but was significantly lower when expressed as nmole/mumole total lipids (0.56+/-0.03 vs 0.64+/-0.04, p = 0.03) from that of maternal-RBC. Vitamin E-quinone levels are significantly elevated in newborns compared with their mothers both in RBC (29.4+/-2.1 vs 24.1+/-1.2, p = 0.04) and plasma (39.9+/-5.3 vs 25.3+/-4.2, p = 0.006) when expressed as nmole/mmole total lipids but not when expressed as nmole/ml. There was a significant correlation of vitamin E between newborn-plasma and newborn-RBC (r = 0.65, p = 0.0002 for nmole per ml packed RBC;r = 0.63, p = 0.0007 for nmole per mumole total lipids). The relationship between maternal plasma and newborn plasma was significant when vitamin E was normalized with nmole/mumole total lipid (r = 0.54, p = 0.007 but not when expressed as nmole/ml (r = 0.09, p = 0.64). However, vitamin E in the RBC of maternal and newborn had significant correlation when expressed as per ml packed cells (r = 0.61, p = 0.001) and per total lipid (r = 0.46, p = 0.02). There was no relationship of vitamin E-quinone levels between RBC and plasma of newborns and their mothers. Elevated blood levels of vitamin E-quinone suggest increased oxidative stress and utilization of vitamin E in newborns compared to their mothers. Because vitamin E levels in RBC of newborns are lower and significantly related to vitamin E levels in RBC of their mothers, an increase in vitamin E supplementation to mothers during pregnancy may increase vitamin E levels in the newborn and help impede the effect of extrauterine oxygen toxicity.

How accurate is glucose analysis in the presence of multiple interfering substances in the neonate? (glucose analysis and interfering substances).

Whole blood glucose testing by reagent sticks is inaccurate at low plasma glucose concentrations and with varying hematocrit. Both conditions are frequently seen in newborn infants. Therefore plasma glucose analysis is the preferred method for newborn glucose monitoring. We encountered unanticipated difficulties in plasma glucose measurement by the automated hexokinase method caused by the combinations of plasma free hemoglobin, bilirubin, and plasma triglycerides, which are frequently elevated in newborn plasma. We determined the adverse effects of various combinations of these interfering substances on glucose analysis by the hexokinase method and demonstrated that accurate analysis is possible by a 1:1 plasma dilution only at high plasma glucose levels but not at the more critical low plasma glucose concentration. The dilution reduced the number of repeat specimens required in newborns. But 1:1 plasma dilution overestimated the glucose levels at low plasma glucose values, and therefore this automated hexokinase method is not suitable for glucose analysis in the newborn. Glucose-oxidase remains the method of choice for plasma glucose analysis in neonates. This information is important because using this hexokinase methodology, one might miss hypoglycemia in the newborn.

Reduced iron-associated antioxidants in premature newborns suffering intracerebral hemorrhage

Oxygen radical injury may be a common pathogenic mechanism in several neonatal diseases. The term “oxygen radical disease of prematurity” has been proposed in the face of the greater incidence of intracerebral hemorrhage, bronchopulmonary dysplasia, and retinopathy in premature neonates. To test the hypothesis that overload with ionic iron due to decreased concentrations of iron-oxidizing and iron-binding proteins induces free radical damage in premature asphyxiated newborns suffering periventricular-intraventricular hemorrhage (PIVH), blood plasma of newborns with PIVH ( n = 7) was compared with that of controls ( n = 10) within the first 12 h of life. We found reduced transferrin (2.05 vs. 2.24 g/l; p < 0.05) and ceruloplasmin (89.9 vs. 126.3 mg/l; p < 0.01) levels and an increased transferrin saturation (54.2 vs. 38.4%; p < 0.05) in those newborns who later developed PIVH. These findings support the theory that iron-catalyzed lipid peroxidation of the brain during reoxygenation after perinatal asphyxia may be involved in the pathogenesis of PIVH.

A serine proteinase involved in contact mediated repulsion of retinal growth cones by DRG neurites

Cultured retinal ganglion cell growth cones avoid neurites extending from PNS explants. Here we characterize a growth cone collapsing activity in detergent extracts of newborn calf adrenal plasma membranes that has characteristics expected for an avoidance cue on peripheral neurites. This adrenal derived activity induces the rapid and reversible collapse of retinal growth cones grown on either of two distinct adhesion substrata, mouse laminin or the chick cell surface axonal glycoprotein G4/NgCAM. The collapsing activity is inhibited by several different types of serine proteinase inhibitors, including the irreversible inhibitor PPACK (D-phenylalanyl-prolyl-arginine chloromethyl ketone). The activity is not inhibited by the specific thrombin inhibitor, hirudin. We have named the adrenal derived collapsing activity erase. PPACK blocks the collapse of temporal retinal growth cones on contact with DRG neurites, but does not block the collapse of the same growth cones on contact with nasal retinal neurites. These results support the hypothesis that a serine proteinase on peripheral axons serves as an avoidance cue which induces contact mediated collapse of retinal growth cones.

Evidence for an endogenous ouabain-like immunoreactive factor in human newborn plasma coeluted with ouabain on HPLC

The identification in human plasma of ouabain as an endogenous digitalis-like factor (EDLF) claimed by Hamlyn et al. has recently been contradicted by two studies which failed to demonstrate endogenous ouabain-like immunoreactivity in HPLC fractions in which exogenous ouabain was eluted. In this paper we report the results obtained on the cross-reactivity with antiouabain antibodies of an EDLF purified by us from human newborn cord plasma. We found that this EDLF coeluted with ouabain on HPLC and cross-reacted both with rabbit anti-ouabain antiserum and with the purified antibodies, which excluded possible interferences due to antibodies directed against non-ouabain portions of the immunogen. Similar but not identical slopes of the ouabain and EDLF displacements curves were observed in all competition ELISA experiments. The inhibitory effect of EDLF on erythrocyte 86Rb uptake was reversed by antiouabain antiserum and antibodies. The concentration of EDLF in newborn plasma, in the four different purifications studied ranged from 30 to 380 pM ouabain equivalents (o.e.) by ELISA and from 100 to 300 pM o.e. by 86Rb uptake. Our data thus support the existence, in human newborn plasma, of a factor with both biological and immunological ouabain-like properties, although not necessarily identical to ouabain.

The effect of long term caffeine treatment on hypoxic-ischemic brain damage in the neonate.

There is considerable concern over the widespread use of caffeine during and after pregnancy. We have therefore examined the effect of perinatal caffeine use on the vulnerability of the immature brain to hypoxic ischemia (HI). Rat pups were exposed to caffeine during the first 7 d after birth by addition of a low or a high dose (0.3 or 0.8 g/L) of caffeine to the drinking water of their dams. At 7 d the pups were exposed to unilateral carotid occlusion+exposure to 7.70% oxygen for 100 min. The extent of HI brain damage was evaluated 2 wk after the insult. The effects of caffeine on A1 and A2a receptors, A1 mRNA and A2a mRNA, were examined by receptor autoradiography and in situ hybridization. Caffeine, theobromine, theophylline, and paraxanthine were analyzed in plasma of separate animals. Exposure to caffeine reduced HI brain damage from 40.3 +/- 3.2% in controls to 29.8 +/- 4.0% (p < 0.05) in low dose and 33.7 +/- 3.9% (NS) in the high dose group. The A1 receptor density measured as [3H]-1,3-dipropyl-8-cyclopentyl xanthine ([3H]-DPCPX) binding was not significantly affected after low dose caffeine but increased in the brain of rat pups in the high dose group. The A2a receptor density measured as [3H]-2[p-(2-carbonylethyl)-phenethylamino]-5'-N- ethylcarboxamidoadenosine ([3H]-CGS 21680) binding and the expression of A1 mRNA and A2a mRNA were not altered by caffeine treatment. In conclusion, low dose caffeine exposure (plasma levels corresponding to umbilical cord plasma in newborns of coffee-consuming mothers) reduced HI brain damage by 30% in 7-d-old rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Measured versus calculated latent iron binding capacity in plasma of newborns.

Iron overload as well as iron deficiency may play a role in the pathogenesis of diseases in the newborn and infant and therefore knowledge of the iron status is essential. Using an automated method for the determination of plasma latent iron-binding capacity (LIBC) we measured the LIBC in 20 full term and 20 preterm babies and 20 adults. LIBC was also calculated from transferrin and iron concentration.

Plasma Somatostatin and Cholecystokinin Levels in Preterm Infants and Their Mothers at Birth

Regulatory gut peptides play an important role in regulating the gastrointestinal tract. Our knowledge about the pattern of secretion and function of these peptides is scanty in preterm infants. Therefore, plasma somatostatin (SS) and cholecystokinin (CCK) levels were estimated just after birth in 65 mothers and 73 preterm infants (umbilical cord blood). The gestational age was 32 (24-36 median ranges) wk and birth weight 1900 (475-3350) g. The umbilical cord blood pH was 7.32 +/- 0.10 (mean +/- SD). After Sep-Pak-C18 semichromatography of plasma, SS and CCK were analyzed by RIA. Both plasma SS and CCK levels were significantly higher in infants than in mothers (SS = 14.5 +/- 12.4 versus 9.3 +/- 7.6 pmol/L; CCK = 11.6 +/- 7.4 versus 7.0 +/- 1.9 pmol/L). In appropriate for gestational age and small for gestational age infants' plasma levels of the two peptides were the same. They were also independent of sex, birth weight, gestational age, umbilical cord blood pH, or glucose level. In mothers, but not in infants, plasma SS levels were higher after vaginal delivery than after cesarean section. After multiple birth, newborn plasma SS, but not plasma CCK, was significantly lower than after single birth (9.1 +/- 7.7 versus 16.9 +/- 12.7 pmol/L).

Characterization of an antithrombotic peptide from kappa-casein in newborn plasma after milk ingestion.

Bovine and human kappa-caseinoglycopeptides, two antithrombotic peptides derived from the corresponding kappa-caseins, were detected in physiologically active concentrations in the plasma of 5-d-old newborn infants after ingestion of cow's-milk-based formula or human milk respectively. It is suggested that these two bioactive peptides are released from milk proteins during digestion.

Maternal and Neonatal Plasma Transthyretin (Prealbumin) Concentrations and Birth Weight of Newborn Infants

Animal studies have shown that maternal protein deficiency during pregnancy affects fetal birth weight. This study has examined whether or not the fetal birth weight of full-term newborns has any relationship with the acute protein nutrition status of the mother. Protein nutrition status was assessed by measuring the plasma transthyretin (prealbumin) concentrations. Plasma transthyretin concentrations (mean +/- SE) from the cord blood of 20 newborns (10.9 +/- 0.5 mg/dl) were significantly lower (p < 0.000000001) compared with respective maternal concentrations (17.8 +/- 0.8). There was a significant correlation of transthyretin concentrations between mother and newborns (r = 0.61, p < 0.005), and of newborn birth weight with plasma transthyretin concentrations of newborns (r = 0.57, p < 0.01) and mothers (r = 0.51, p < 0.03). This study documents a relationship of fetal birth weight with maternal and newborn plasma transthyretin concentrations.

OXIDATIVE STRESS AND LIPID PEROXIDATION IN THE NEWBORN

Increasing appreciation of the causative role of oxidative injury in the development of many severe diseases of the newborn places great importance on the reliable assessment of lipid peroxidation. Lipid peroxidation in the erythrocyte membrane has been widely investigated but little has been reported on lipid peroxidation in the plasma The aim of the present paper was to evaluate lipid peroxidation and peroxidation tissue injury in the plasma of newborns using the concentration of Malondialdehyde (MDA). one of the several substances formed when lipid hydroperoxides break down in biological systems Twenty-one, healthy, full-term newborn infants, (10 male and 11 female), with an Apgar score of more than 8 at 1 min, were studied. Fifteen were born by vaginal delivery (VD) and 6 by elective cesaerean section (ECS) Hepannized blood samples were taken at birth from the cord blood and on the 4th day of life from a peripheral vein MDA levels were determined by fluorometric assay using the MDA Kit (Sobioda, Grenoble France) We found significantly lower concentrations of MDA at birth (2 81±1 34 nmol/mL. meant±SD) than on 4th day of life (4.35±1.98. P<0 0003) in total population. This difference was also observed in the two mode of delivery when considered separately. No statistically significant differences were found between the two groups nor between the sexes. These results clearly demonstrate a significant increase in lipid peroxidation after birth. We speculate that environmental changes in O2 concentration from fetal to postnatal life are sufficient to produce an increase in aerobic metabolism and in the rate of free radical generation The deficient antioxidant mechanisms at birth could impair normal fetal equilibrium between oxygen free radical generation and free radical detoxification

THE PERSISTENCE OF NON-PROTEIN-BOUND PLASMA IRON IN PRETERM INFANTS

Non-protein-bound iron (npb-iron), a potent prooxidant, is present in newborn plasma, and can induce peroxidation of surfactant (Moison et al, Lancet 1993;341:79). This study assessed the persistence of npb-iron (bleomycine assay) in 26 infants (GA; 26-34 wks) for the first 10 days of life. Npb-iron was present in 10 (38%), 7 (27%) and 2 (8%) infants at day 1, 4 and 10 respectively. In 5 babies npb-iron was not present at day 1 but developed at day 4, and in 2 of them it persisted until day 10. Npb-iron was more frequently present in the more immature babies (p<0.01) and in babies with a longer duration of O2 therapy (mean(SD): npb-iron pos 121.4 (174.8), npb-iron neg: 22.3 (40.0) hrs, p<0.01), whereas the level of the peroxidation product TBARS did not differ in infants with or without npb-iron. The babies who developed npb-iron at day 4 had a longer duration of O2 therapy than babies with npb-iron already present at day 1 (p<0.01). Npb-iron induced oxidative damage could play a role in the pathogenesis of acute and chronic lung disease in the newborn.

Plasma epinephrine appearance and clearance rates in fetal and newborn sheep

Newborn plasma catecholamine levels are elevated compared to fetal life. Whether this reflects increased catecholamine secretion after birth or decreased clearance is not known. To determine the plasma appearance and clearance rates for catecholamines during the transition to postnatal life, we compared plasma epinephrine appearance and clearance rates in fetal sheep before birth and in newborns after delivery. Plasma epinephrine appearance and clearance rates were measured by radiotracer analysis in eight fetuses at 127 +/- 1 days of gestation and, after cesarean delivery, at 130 +/- 1 days of gestation. There was no difference in plasma epinephrine appearance rate during the fetal (26 +/- 4 ng.kg-1 x min-1) or newborn studies (31 +/- 5 ng.kg-1 x min-1). The fetal plasma epinephrine clearance rate (131 +/- 13 ml.kg-1 x min-1) was significantly higher than newborn plasma epinephrine clearance rate (40 +/- 3 ml.kg-1 x min-1). Thus fetal plasma epinephrine appearance rate is not different from appearance rate in the immediate newborn period when catecholamine levels are higher than during most other physiological circumstances. The increase in circulating catecholamine levels at birth is due in part to a significant decrease in clearance rate. It is likely that removal of the placental contribution to whole body clearance accounts for much of the difference observed in fetal and newborn clearance rates.

Physiologic Levels of Uric Acid Inhibit Xanthine Oxidase in Human Plasma

Xanthine oxidase, a key source of reactive oxygen species, and purine substrates are detected in the circulation after ischemia-reperfusion. High levels of uric acid, produced by a xanthine oxidase-catalyzed reaction, are found in human plasma. We studied whether uric acid could alter xanthine oxidase activity in plasma obtained from eight adults and eight neonates. Known amounts of uric acid were added to xanthine and xanthine oxidase-supplemented buffer and plasma, and the production of uric acid and superoxide was determined. Uric acid, 150 and 300 microM, decreased the oxidation of xanthine to uric acid in adult plasma by 37.5 +/- 5.6 and 48.9 +/- 6.1% and formation of superoxide by 23.2 +/- 1.9 and 32.0 +/- 2.3%, respectively, compared with plasma without uric acid. In newborn plasma, a similar pattern and extent of inhibition was observed. Superoxide formation, however, was inhibited to a greater extent than in adult plasma. Endogenous xanthine oxidase was detected in newborn plasma in nine additional neonates using HPLC. These results indicate that uric acid is an effective inhibitor of the formation of superoxide and hydrogen peroxide by xanthine oxidase at the levels found in human plasma. Plasma uric acid may play an important role in attenuating the oxidant-mediated tissue damage caused by xanthine oxidase released into the circulation during ischemia-reperfusion.