Newborn Plasma Research Articles

Comparison of surface charge and ADP induced electrokinetic behaviour of fetal and adult platelets: 79

The electrophoretic mobility of washed platelets as well as of platelets suspended in diluted plasma obtained from adults and newborns was practically the same. No significant difference could be observed in the pH-mobility relationship of the two types of platelets. These comparative studies indicate that the actual charge density, i.e. the number and sign of the charges groups at the fetal and adult platelet surface are essentially identical.Significant difference between the two platelet population was found, however, in the mobility changes induced by ADP. On the basis of "cross over" experiments between the platelets and plasma of adults and newborns it seems likely that the different behaviour of fetal platelets arises from a dissimilarity between adult and fetal plasma. The adult plasma might have a factor which is not present in the fetal plasma. Preliminary results indicate that this factor is a plasma component with mol.wt. about 10 000.

Decreased Phytohemagglutinin-Induced Aggregation and C5a-Induced Chemotaxis of Human Newborn Neutrophils

Phytohemmagglutinin (PHA)-induced lectin aggregation, chemotactic response to C5a, and random migration were measured on paired samples of neutrophils obtained from human peripheral blood and cord blood of normal newborn infants. The mean aggregation rate (+/- 1 SD) of adult neutrophils with PHA was 16.8 +/- 4.4 vs. 12.0 +/- 3.6 for newborn neutrophils (P less than 0.005), and the mean percent aggregation of adult neutrophils was 56.2 +/- 9.2 vs. 45.6 +/- 8.3 for newborn neutrophils (P less than 0.005). Exposure to newborn plasma had no affect on adult neutrophil aggregation. Whereas vinblastine (VBL) decreased both the percent and rate of PHA-induced adult neutrophil aggregation, only the rate of newborn neutrophil aggregation was reduced by VBL. Newborn neutrophil chemotactic response to C5a, was reduced by 80% (P less than 0.0025), and showed a positive correlation with percent PHA-induced aggregation (r = 0.6037, P less than 0.05). On the other hand, random migration was not significantly reduced and did not correlate with PHA-induced aggregation. These observations suggest that the decreased chemotactic responsiveness of newborn neutrophils may be due to developmental membrane differences which adversely affect the number and/or availability of C5a resceptors. Lectin-induced aggregation studies of other chemotactic defects may identify similar differences.

Ontogeny of the renin-angiotensin-aldosterone system in the fetal and newborn lamb.

Thirteen chronic fetal lamb preparations between 95 and 142 days of gestation (term 145--150 days), and 10 newborn lambs were studied before and after the acute (1--2 min) infusion of furosemide (2 mg/kg). The baseline to peak plasma renin activity (PRA) response to furosemide increased from delta 3.0 +/- 1.3 ng/ml/hr (M and SEM) and 95--106 days of gestation to delta 18.4 +/- 4.0 (P less than 0.01) at 123--142 days and delta 33.6 +/- 6.5 (P less than 0.001) in the newborn. Baseline plasma aldosterone concentrations were similar in the fetus and pregnant ewe; aldosterone levels were higher in the newborn lamb than in the nonpregnant ewe. The newborn plasma aldosterone response to furosemide via the endogenous renin-angiotensin was delta 17.1 +/- 4.2 ng/dl (P less than 0.01); the fetal lamb plasma aldosterone level did not increase. The results indicate that the renin-angiotensin system cannot be stimulated by furosemide under 106 days of gestation; the response after 110 days increases with gestational age. Aldosterone concentrations in the fetal lamb are probably maintained primarily by the pregnant ewe and do not increase in response to endogenous renin stimulation as in the newborn.

Thyrotropin-releasing hormone-degrading activity of neonatal human plasma.

Thyroid physiology changes rapidly during the neonatal period. Thus, there is an abrupt release of TSH which peaks within 30 min after birth and there are significant increases in the plasma concentrations of T3 and T4, which peak 24--48 h after birth. In the present work, high pressure liquid chromatography was used to study the evolution of TRH-degrading activity in the plasma of newborns during the first 5 days of life. TRH-degrading activity is initially absent in cord blood and appears after 3 days of life. It reaches maternal or nonpregnant adult euthyroid plasma levels after 5 days. The exact role of this phenomenon is unknown. A possible effect of plasma T3 levels on the enzymatic degradation of TRH is postulated.

Plasma TRH degrading activity (RTH-DA) in human nenotal plasma

In vitro degradation of TRH by human plasma has been demonstrated in adults. This study concerns plasma TRH-DA during the neonatal period.(H3)TRH is incubated in 50ul of plasma, extracted and intact (H3)TRH quantitated by high pressure liquid chromatography after one hour incubation period.(H3)TRH after 0 minute incubation is the reference value and results are expressed in % TRH remaining after one hour.Paired mother and newborn (arterial cord plasma) n=7 and neonates from day 1 to 5 (n=5 each day) are studied.Maternal values TRH-DA are not significantly different from adult euthyroid control (37.5±5). Plasma of neonate have a very low TRH-DA.Activity appears at day 3 and reachs maternal values at day 5. The known increase of plasma T3 level in newborn occurs 2 days before appearance of any degrading activity.In conclusion - Plasma of newborns have no TRH-DA until day 3. This metabolic immaturity may play a role in the neonatal thyroid hyperactivity. T3 induction of this enzymatic process demonstrated in rats as to be considered in human.

Factor VIII Procoagulant Activity, Factor VIII Related Antigen and von Willebrand Factor in Newborn Cord Blood

The mean level of factor VIII procoagulant acitivity (VIII:C) and factor VIII related antigen (VIIIR:AG) was normal in 100 newborn cord plasmas, whereas that of von Willebrand factor (VIIIR:WF) activity was slightly lower than normal. On crossed immunoelectrophoresis, 20 of 50 newborn infants had an increased anodal mobility of VIIIR:AG. When the cord plasma showing an abnormal electrophoretic pattern was mixed with normal plasma, two precipitation peaks with a broad base were found. Similar mixing experiments with the abnormal cord plasma and plasma from a patient with atypical von Willebrand's disease did not normalize the electrophoretic mobility of VIIIR:AG. Gel filtration of the cord plasma with an abnormal electrophoretic pattern of VIII:AG, showed that the three activities were all detected at the position corresponding to a molecular weight of about 800 000. The results suggest the presence of qualitative abnormalities of the factor VIII molecule in half of full-term newborn cord plasma.

Fetal and adult albumins are indistinguishable by immunological and physicochemical criteria

The existence of a functionally immature fetal albumin has been postulated to explain the reduced ability of newborn plasma to bind bilirubin and various drugs. In support of this, cord and adult albumin, isolated by a simple salting-out technique, were reported to differ in electrophoretic and chromatographic properties and in their resistance to alkali and proteolytic enzymes. However, the interpretation of these findings has since been questioned. To resolve this controversy, we have purified to homogeneity human serum albumins from pooled umbilical cord and adult donor plasma. The two albumins were compared and found to be indistinguishable by polyacrylamide gel electrophoresis with and without sodium dodecyl sulfate, as well as by immunoelectrophoresis and double immunodiffusion using specific antibodies against both albumins. Furthermore, the amino acid compositions, the aminoterminal sequence (Asp-Ala-His-Lys-Ser-Glu-Val-Ala-), the carboxy terminus (Leu), and the peptide fingerprints were identical in the two albumins. No significant differences were found by circular dichroism in the ultraviolet (200-350 nm). Binding studies with bilirubin showed association constants of 3.7 +/- 0.7 x 10(7) M(-1) for cord and 2.9 +/- 0.3 x 10(7) M(-1) for adult albumin, respectively. The circular dichroic spectra of 1:1 bilirubin.albumin complexes showed considerable variation between the batches but were not significantly different. The only difference was found in the fluorescence spectra of the bilirubin.albumin complexes, in which complexes with adult albumin showed only 75% of the relative fluorescence exhibited with cord albumin. The combined results nevertheless strongly indicate that fetal and adult albumins are very similar, if not identical.

Catecholamine levels in newborn human plasma in normal and abnormal conditions and in maternal plasma at delivery

High levels of catecholamines have been found in plasma from the umbilical cord of newborn infants, suggesting a release of catecholamine from the fetus during parturition. Plasma catecholamine levels are also elevated in mothers at delivery.

An inhibitor of clot formation in cord plasma

An inhibitor of the coagulation in cord plasma can be extracted by phosphotungstic acid or acetone. The way of action of this inhibitor is tested by means of synthetic chromogenic substrates, thrombin times, two-stage thrombin generation tests and thrombelastography. This inhibitor seems to act mainly on the behaviour of fibrin. The possibility cannot be excluded that the inhibitor also has a small effect on thrombin or thrombin generation. Some differences in the coagulation of adult and newborn plasma may be explained by this newborn inhibitor.

1104 CRYOACTIVATION AND ACID ACTIVATION OF AN INACTIVE RENIN IN THE NEWBORN INFANT

An inactive large molecular form of renin which can be acid and cryoactivated has been described in human amniotic fluid and plasma. The present study was conducted to determine whether the concentration of inactive renin is high in the newborn at a time when circulating active renin levels are known to be elevated, and whether inactive newborn renin can be separated from active renin by chromatography. 78 samples of newborn plasma were acidified to ph 5.5-5.7, the optimal ph for generating angiotensin I (angio I) from active renin, and treated with Bal and 8-OH quinoline to prevent formation of angiotensin 2. The samples were divided into 2 equal parts, one control for circulating angio I and one generated to angio I at 37°C for 1 hr prior to RIA. The control and generated samples were placed in an ice bath (3-4°C) for 10 hrs. The control samples contained 6.7 ± 1.0 ng/ml/hr (M and SEM) of active renin, and 14.1 ± 1.8 of cryoactivated renin (as PRA). The (37°C, 1 hr) generated samples contained 22.8 ± 1.3 ng/ml/hr of active renin and 17.7 ± 1.7 of cryoactivated renin (as PRA). Chromatography on 1M G-75 Sephadex columns eluted with 0.1M Na Phosphate buffer, ph 6.9 showed active renin in one fraction, M.W. 45,000, and cryoactivated and acid activated (ph 3.0) renin in another fraction, M.W. 67,000. Conclusions: a) active and inactive renin are both in high concentration in newborn plasma, b) cryoactivated and acid activated renin are of similar M.W. and larger than active renin.

Pharmacokinetic observations of phenytoin disposition in the newborn and young infant.

The pharmacokinetic profile of phenytoin (DPH) was studied in 30 infants aged 2 days to 96 weeks. The plasma DPH half-life during the first week of life in term infants was prolonged and very variable (20-7 +/- 11-6 h, mean +/-SD). Thereafter the plasma half-life was much shorter (7-6 +/- 3-5 h). In preterm infants the half-life was much longer (75-4 +/- 64-5 h) and more variable. The mean apparent volume of distribution was similar in these groups of infants: preterm newborn 0-80 +/- 0-22 l/kg, term infants during the first week of life 0-80 +/- 0-26 l/kg, and term infants greater than 2 weeks of age 0-73 +/- 0-18 l/kg. Predictions of steady-state plasma DPH concentrations, based on these kinetic parameters, were confirmed. Very low "trough" plasma DPH concentrations were observed after the 14th postnatal day in 19 infants receiving 8 mg/kg per 24 h orally. On the other hand, infants of less than one week of age receiving the same dose, especially if preterm, frequently showed drug accumulation to toxic plasma DPH concentrations. The impaired binding of DPH to newborn plasma protein was confirmed but "normal adult values" were approached by the age of 3 months. An intravenous loading dose of 8 mg/kg (sodium phenytoin) can be expected to generate a mean plasma DPH concentration of 10 mg/l (40 micronmol/l) in the newborn. Loading doses of up to 12 mg/kg were given without untoward effects. During the first week or so of life plasma Dph half-life is so variable that no fixed dosage regimen can be derived from the available data. Beyond the second week of life, however, a dose of 8 mg/kg per 24 h is probably inadequate for most infants.

155: Mitotic response to phytohaemagglutinin (PHA) of lymphocytes during the neonatal period

Lymphocyte function measured by the assay of mitotic response to PHA was studied in the blood of 46 fullterm and 51 premature neonates. The lymphocyte cultures were incubated for 72 hours at 37°C and DMA synthesis was estimated by incorporation of [125J] 5-iodo-deoxyuridine. DNA synthesis in unstimulated cultures from premature or fullterm newborns was significantly greater than in adult controls (p < 0.001). With the maximal PHA stimulation dose the mitotic response of neonates both fullterm and prematures during the first 4 days of life was significantly lower than in adults (p < 0.001). However it rose to adult levels after the 4th day. In the presence of the submaximal PHA dose the mitotic response was similar in adults and neonates in the first days of life and later. These findings indicate decreased mitogenic capacity of the lymphocytes during the first days of life suggesting either functional immaturity or the presence of an inhibitory factor in the newborn's plasma.

Plasma Cortisol Levels in Umbilical Cord Plasma and Its Change During the First Two Hours Following Delivery

Although assessment of adrenocortical function at birth has been made by several investigators, the results obtained do not agree well with one another. Also, knowledge of the cortisol level during the postnatal period was scanty. The purpose of the present study is : 1) to assess cortisol levels in normal newborns at birth and to compare them with levels in distressed newborns ; 2) to investigate changes of plasma cortisol levels in normal babies during the first 2 hours following delivery.Cortisol was measured in maternal and cord plasma, as well as in normal newborn plasma by a competitive protein-binding radioassay. An assessment of the reproducibility and precision of the method is presented. In maternal plasma, the average cortisol concentration (32. 4 μg/dl) was 2. 4 times greater than in umbilical arterial plasma (13. 3 μg/dl). The correlation coefficients do not suggest a significant relationship between the maternal and umbilical venous cortisol concentrations which means poor placental transfer of cortisol.To determine whether distressed infants showed evidence of adrenal cortical hyperfunction as compared to normal babies, serum cortisol levels were measured in infants delivered by vacuum extraction or forceps. No difference was found in circulation cortisol levels between these groups. However, Gemzell observed a higher 17-hydroxycorticosteroids concentration in the infants delivered by low forceps than in normal infants. These results suggest that the ability of the neonatal adrenal cortex to respond in the face of perinatal stress is variable according to individuals.Cortisol concentrations from normal infants at 1/2, 1, 2, 6, 12, 24 hours after birth were measured. In spite of individual variations and the limited number of observations, it is apparent that the cortisol concentration fell after birth. The levels of cortisone obtained at 1 hour of age were about half the levels at birth and were maintained during the first day of life.

Exchange transfusions with concentrated ACD-blood. II. Effects on bilirubin, total protein, chloride, phosphate, calcium, magnesium and potassium.

During ten exchange transfusions with ACD-blood (NIH, sol. B), newborn infants' bilirubin, plasma protein and electrolyte gain or loss were studied quantitatively. The loss of bilirubin was closely correlated to the pre-exchange bilirubin concentration. On the average, there was a significant loss of plasma chloride of 3.21 mmol per kg bodyweight. There were no significant gains or losses of plasma protein or sodium, potassium, magnesium and calcium of whole blood during the ET. There was a calculated significant inflow of whole blood calcium from the extravascular space of 0.02 mmol per kg bodyweight together with a calculated significant increase of plasma phosphate of 0.06 mmol per kg bodyweight.

Binding of 14-C-salicylic acid and 14-C-pentobarbital to plasma proteins of several species during the perinatal period.

The fraction binding of 14-C-salicylic acid and 14-C-pentobarbital was studied as a function of age in plasma of the pig, dog, goat and human. The pig exhibited an unusual degree of hypoalbuminemia and low fractional binding of salicylic acid at birth. Albumin levels and the percent binding of the salicylic acid were not significantly lower in newborn plasma than in adult plasma of the other species studied. The pig was also exceptional in that the high fractional binding of pentobarbital observed at low ligand concentrations in plasma of the newborn was not observed in the other species studied. Depletion of albumin in newborn pig plasma did not appreciably affect the binding of pentobarbital. Thus it is suggested that the plasma of the fetal and newborn pig may contain a nonalbuminoid protein, such as fetal globulin, which is capable of binding pentobarbital but does not have a high avidity for salicylic acid. It apparently does not exist at birth in the plasmas of the other species studied, as depletion of albumin markedly reduced the fractional binding of pentobarbital.

Thin-Layer Chromatographic Screening of Amino Acids in Plasma and Urine of Newborns

Abstract We describe a simple, rapid, and inexpensive unidimensional high-resolution thin-layer chromatographic procedure for screening for aminoacidopathies in newborns. Protein-free filtrates are prepared for ultrafiltration of as little as 10 µl of plasma. A rapid, inexpensive photographic method provides large, high-contrast pictures of the chromatograms for permanent records. A day’s samples can be completed in 3 h, including all phases of the procedure.

Mycoplasma species in a dysplasia clinic population

of the stomach contents varied from 150 to 300 ~1 and did not correlate with the increase in fetal plasma glucose levels. Amniotic fluid glucose concentrations did not change. Fetal plasma insulin, growth hormone. and glucagon concentrations were not altered despite fetal hyperglycemia. Maternal plasma glucose, insulin, and glucagon concentrations also did not change during the experiments. Glucose (1.0 Gm.) was instilled into the stomach of 5 premature newborn monkeys (144 to 154 days’ gestation) at 4 or 5 hours of life. The weights ranged from 350 to 442 grams. Plasma glucose concentrations were between 51 and 153 mg. per cent above base line by 60 minutes after the instillation. Plasma insulin levels increased two- to four-fold from 30 to 60 minutes in 3 animals and did not change in the 2 others. Plasma growth hormone and glucagon concentrations did not change through the experiment. In the human adult, intragastric glucose is more effective as an insulinogenic stimulus than intravascular glucose. The relationship of a series of gastrointestinal hormones (secretin, pancreozymin, gastrin, and extracts of the gastrointestinal tract with glucagon-like immunoreactivity), collectively termed the enteroinsular axis, to this finding presently is being defined.” This study was designed to examine the question of whether gastrointestinal hormones which augment islet cell secretion during digestion in adults also function during fetal/neonatal life. We observed no insulin response to hyperglycemia induced in the fetal monkey by instilling glucose into the stomach and a delayed insulin response in the newborn monkey. These observations do not differ from our previous studies on the effects of intravascularly induced hyperglycemia in the fetal and newborn primate.’ Detectable amounts of gastrointestinal glucagon-like material in human newborn portal vein plasma are absent; similar information on other gut hormones has not been published.’ Thus, whether the failure of orally administered glucose to stimulate an early (adultlike) insulin response in the fetal and newborn monkey is because of a deficiency in the enteroinsular axis hormones or islet cell unresponsiveness to them remains for future study.

FREE AMINO ACID CONCENTRATIONS IN FETAL SERUM

A number of inborn errors of metabolism (IEM) are not yet prenatally detectable. Perhaps most prominent among these is phenylketonuria. It is possible that in the presence of an IEM, the affected fetus will accumulate increased quantities of one or more of the metabolites and that such increases will be detectable by careful analyses of blood. In order to make such determinations, however, adequate methods and normal values must be available. We have quantitatively examined the serum free amino acids in seven fetuses of 12-20 weeks gestation. In most of the examinations 0.1 ml. serum was used although as little as 0.05 ml. was adequate. The serum was diluted and deproteinized in 1.0 ml. 3% sulfosalicylic acid, centrifuged, and the entire supernatant applied to an amino acid analyzer column. Qualitatively, amino acids were the same as those in postnatal blood or amniotic fluid. Amino acid concentrations were generally 2-3 times greater than corresponding concentrations as previously determined in amniotic fluid or maternal plasma of the same gestational time and of newborn plasma obtained on the first day of life. Specific values in u moles/ml, include Phe (.174 ± .049), Lys (.569 ± .138) and Ala (.580 ± .150), the latter two particularly concentrated. Within the gestational range examined, there were no consistent differences in the amino acid concentrations.

The activity of platelet factor 4 in plasma of healthy and high risk newborns.

The plasmatic platelet factor 4 activity (PF4) and the platelet count were determined in cord blood (group I) and scalp vein blood (group II) of 70 infants. The PF4, measured upon its anti-heparin activity, and the platelet count were found in healthy infants of both groups within the normal range of healthy adults. High risk infants of both groups demonstrated a significant elevation of PF4 activity and a significantly (group I) or markedly (group II) decreased platelet count. There was a positive correlation between the increased PF4 and decreased platelet count in the high risk infants of group I. These changes among the high risk infants are probably due to activation of the coagulation system evoked by fetal or perinatal distress. The high risk conditions encountered in both groups were in accordance with those known to promote disseminated intravasal coagulation in newborns.

Red cell enzymes in cord blood and plasma bilirubin levels in the first week of life

Cord blood of 300 randomly selected healthy full-term newborn babies (98 Chinese, 102 Malays and 100 Indians) was examined for maternal—foetal blood group incompatibility, haemoglobin types, glutathione level and activities of glucose-6-phosphate dehydrogenase, glutathione reductase, glutathione peroxidase, pyruvate kinase and methaemoglobin reductase, and each newborn's total plasma bilirubin level was estimated daily for one week. 5.6% of the babies developed severe hyperbilirubinaemia of 15 mg/100 ml or higher, three requiring exchange blood transfusion. Babies with maternal—foetal blood group incompatibility and glucose-6-phosphate dehydrogenase deficiency had significantly higher mean bilirubin curves than “normal” babies. Among newborns without known abnormalities Chinese had the highest mean bilirubin curve, Indians the lowest. In all three races, maximum bilirubin level was reached on the fourth day. Neonates with low glutathione reductase activity had a significantly higher mean bilirubin curve. No such pattern was seen for glutathione, glutathione peroxidase, pyruvate kinase or methaemoglobin reductase.