Microdetermination of unbound bilirubin in icteric newborn sera: an enzymatic method employing peroxidase and glucose oxidase

An enzymatic assay method for the microdetermination of unbound bilirubin in newborn icteric sera is described. Unbound bilirubin is oxidized to colorless compounds by peroxidase in the presence of hydrogen peroxide derived from glucose by the mediation of glucose oxidase. In this method, the bilirubin is not significantly degraded before the addition of peroxidase, in contrast to the method using hydrogen peroxide. The oxidation rate is determined by spectrophotometry and chloroform extraction is eliminated. The unbound bilirubin concentration can be determined from the initial oxidation velocity of total bilirubin. The Michaelis constant, KM, was approximately 20 micrometer. The coefficient of variation for icteric serum determination was 4.4--6.5%. The concentration of unbound bilirubin was reduced after five days of storage at -20 degrees C. The bilirubin-albumin affinity was studied with purified albumin and adult serum. The dissociation constants were 2 x 10(-8) M and 5 x 10(-9) M, respectively, at bilirubin/albuminor molar ratios below 1.0. Clinically, serum samples from 75 icteric newborn infants were analysed, and the sera of premature infants were found to have remarkably high levels of unbound bilirubin compared to those of fullterm infants. The sera of a Rhesus immunization infant and an ABO incompatibility infant were remarkably higher than that of the nonhemolytic icteric sera. The unbound bilirubin concentration was also affected, in an in vitro study, by the addition of hemolysate.     

Taste-mediated calming in premature, preterm, and full-term human infants.

Calming by sucrose and glucose was evaluated in premature, preterm, and term infants. In Experiment 1, 9 preterm and 9 term infants each received 0.5 ml (0.1 ml/min) sucrose (12% w/v) solution; 9 age-matched preterm and 9 other term infants received water. In Experiment 2, 9 premature and 9 term infants received a 10% glucose solution. Sucrose reduced crying in preterm and term infants by 91% and 93%, respectively. Glucose reduced crying in premature and term infants by 86% and 81%, respectively. Water was ineffective in both preterm and term infants. Thus, reduced crying cannot be attributed to fluid ingestion per se. Calm induced by either sugar persisted longest in term infants after conclusion of sugar delivery. Accordingly, sensory systems that detect sweet taste and central mechanisms that transduce this change to calm crying infants are functional before normal term and may be engaged during the initial suckling bouts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ultrasonography and neuropathological findings in premature infants

At most maternity units all premature infants are investigated by cranial ultrasonography as a routine. We examined the correlation between autopsy findings and ultrasound examination in 30 premature newborn. The ultrasound examination demonstrated bleeding in 17 (65%) of the 26 cases where autopsy had revealed bleeding. In these 17 patients good correlation was found between the degree of bleeding in the two examinations (ultrasonography and autopsy). In ten patients autopsy showed periventricular leucomalacia, but ultrasonography showed this condition in only two of these. In five cases bleeding made the examination and interpretation of the ultrasound findings difficult. In three patients ultrasonography was thought to be normal, while autopsy demonstrated periventricular leucomalacia.     

Effects of pregnancy on hemoglobin AIc in normal, gestational diabetic, and diabetic women

Hemoglobin AIc, a normal minor hemoglobin, has glucose linked by a Schiff base to the N-terminal end of the beta chain. The glucose interferes with the binding of 2,3 diphosphoglycerate, probably resulting in an increased affinity of that hemoglobin for oxygen. Hb AIc is increased to twice normal levels in juvenile-onset (insulin-dependent) diabetes. In the present studies, the Hb AIc, when expressed as per cent of total hemoglobin, was found to be elevated slightly in pregnany normal (m = 6.97 per cent), pregnant nondiabetic obese (m = 6.89 per cent), and gestationally diabetic subjects (m = 8.77 per cent) above that of normal females (m = 5.68 per cent). A remarkable difference was observed between the nonpregnant diabetics (m = 12.77 per cent) and the pregnant diabetics (m = 8.46 per cent). This decrease in the level of Hb AIc in diabetics who are pregnant more than 30 weeks may reflect either a better state of diabetic control and/or a compensatory mechanism to protect the fetus by facilitating oxygen exchange from mother to fetus.     

Magnesium homeostasis in premature and full-term neonates

Renal handling of magnesium (Mg) has not been comprehensively studied in the newborn period due to the difficulty, until recently, of measuring the diffusible fraction of plasma Mg (UfMg). In the present study this methodology was used to assess Mg homeostasis in 84 newborn infants of different postconceptional age (26-42 weeks), weight (720-4,830 g) and postnatal age (1-72 days). Very premature infants (postconceptional age less than 35 weeks) had significantly higher values of plasma Mg than mature newborn infants. Plasma Mg related inversely to postconceptional age, weight, plasma total protein and plasma calcium, and directly to plasma potassium. Stepwise multiple regression analysis revealed that postconceptional age was the unique factor contributing to variations in plasma Mg. Plasma values of UfMg were the same in preterm as in term infants but, when expressed as a fraction of total plasma Mg (UfMg/Mg), they were significantly lower in very preterm infants. Fractional excretion of Mg and the ratio of urine Mg to urine creatinine did not vary as a function of postconceptional age. These results indicate that plasma UfMg is kept constant at different gestational ages despite variations in total plasma Mg; furthermore, no functional immaturity is present for renal tubular reabsorption of Mg, even in very low birth weight infants.     

CT and MRI characteristics of intracranial hemorrhage complicating breech and vacuum delivery

The CT/MRI brain findings and sequelae of intracranial hemorrhage resulting from traumatic breech and vacuum delivery of 16 term newborn infants are presented. Eleven infants were vacuum extracted, while the remaining five infants were delivered breech. Except for three breech-delivered infants who had intraventricular hemorrhage, the location and nature of hemorrhage were similar in both groups. Nine of the 11 vacuum-extracted babies showed complete resolution of hemorrhage on follow-up examination. None of the breech cases had a normal outcome. All five of the latter group had hydrocephalus, and one case each demonstrated porencephaly and encephalomalacia.     

Closure of the ductus venosus in premature infants: findings on real-time gray-scale, color-flow Doppler, and duplex Doppler sonography

OBJECTIVE: Our objective was to use gray-scale, color-flow, and duplex Doppler sonography to study the anatomy, flow pattern, and time of closure of the ductus venosus in healthy premature infants. SUBJECTS AND METHODS: We prospectively examined the ductus venosus in 130 premature infants whom we divided into two groups: Group I comprised 27 neonates of gestational age 28-32 weeks, and group II comprised 103 neonates of gestational age 33-36 weeks. Neonates who had undergone umbilical vessel manipulation were excluded from the study. All examinations included gray-scale, color-flow, and duplex Doppler sonography. Patency, length, color flow, and Doppler characteristics of the ductus venosus were recorded. Neonates were examined 1-2 days after birth, 6-7 days after birth, and subsequently every 3-4 days until ductus closure was observed. The time of closure of the ductus for the two groups was compared using the chi-square test. RESULTS: The ductus venosus was patent during the initial examination in 128 of the 130 neonates. Doppler waveform was venous with little variation in velocity. Ductus length slightly exceeded 1 cm in both groups. We found a statistically significant difference in the percentage of infants having a patent ductus venosus after the initial examination: At 1 week after birth, ductus patency was shown in 85% of the infants in group I and in 56% of the infants in group II; at 2 weeks, the respective percentages were 42% and 14%; and at 3 weeks, 27% and 0%. CONCLUSION: The ductus venosus is patent 1-2 days after birth in virtually all premature infants. From 6 days after birth and onward, a significantly greater percentage of smaller premature infants (i.e., 28-32 weeks' gestational age) have a patent ductus venosus than do larger premature infants (i.e., 33-36 weeks' gestational age).     

Detection of thyrotropin binding inhibitory activity in neonatal blood spots

Recent studies have suggested that maternal TSH receptor-blocking antibodies might be of primary etiological importance in some cases of transient congenital hypothyroidism (CH). Because these antibodies are extremely potent, we evaluated the feasibility of identifying babies at risk by using readily available newborn blood spots. Blood spots obtained from 84 normal babies (group 1) and from 354 infants whose initial T4 was less than the tenth percentile for the assay and whose TSH was 40 mU/L or more (group 2) were studied without knowledge of the diagnosis. Blood was eluted from spots overnight and evaluated for [125I]TSH binding inhibition (TBI) to solubilized porcine thyroid membranes. Four spots obtained from 3 group 2 babies, but none of those from the group 1 infants, exhibited TBI activity greater than 3 SD above the normal mean (33.9%). Four additional hypothyroxinemic infants whose mothers had Graves' disease were also negative. Subsequent follow-up revealed that all 3 positive babies had transient CH, and all 3 mothers had primary myxedema. Potent TBI activity was confirmed in the serum of all 3 mothers and in the 2 babies in whom it was evaluated at birth. We conclude that newborn blood spots can be used to detect potent maternal TBI activity, and that this identifies a baby likely to have transient, rather than permanent, CH. Because of their stability and ease of collection and handling, newborn blood spots should offer a convenient tool for future studies aimed at defining in more detail the incidence and clinical characteristics of this unique syndrome.     

A single glucose transporter configuration in normal primate brain endothelium: comparison with resected human brain

Cellular distribution of the Glut1 glucose transporter in normal primate brains was analyzed by immunogold electron microscopy. Two configurations of endothelial Glut1 glucose transporter (high and low density capillaries) have been found in resections of traumatically injured and epileptogenic human brain; the objective of the present study was to ascertain whether these same 2 capillary populations, expressing high and low glucose transporter densities, were the common configuration in normal brain. The relative numbers of Glut1 glucose transporter-associated gold particles on luminal and abluminal endothelial cell membranes were determined within the cerebral cortex of several normal, nonhuman primates. Low Glut1 densities were seen in brain endothelia of both the rhesus and squirrel monkey cortex, with slightly greater quantities of Glut1 in vervet monkey cortices. The Glut1 transporter was most highly expressed in the baboon cortex, approaching the concentrations seen in human brains. In the rhesus, squirrel, and vervet monkeys, Glut1 concentrations were greater on the abluminal than luminal capillary membranes. In contrast, mean luminal membrane Glut1 concentrations were greater in baboons, resembling the distribution seen in the human brain. Brain regional differences in transporter concentration were seen in comparing membrane densities in the baboon cortex (approximately 15 Glut1-gold particles per micrometer), hippocampus (approximately 12 Glut1 gold particles per micrometer), cerebellum (approximately 6 Glut1-gold particles per micrometer), and retinal microvasculature (approximately 20 Glut1-gold particles per micrometer). We conclude that a single, uniform Glut1 distribution characterizes brain capillaries of normal nonhuman primates, and hypothesize that the presence of high and low density glucose transporter endothelial cells (seen in human traumatic injury and seizure resections) represents a pathologic response to brain insult.     

Learning in premature infants.

Examined instrumental learning in premature infants by using a teddy bear that "breathed" quietly at a rate that reflected the infant's respiration rate. At 33 wks conceptional age (CA), 45 infants were provided with a breathing bear (BRB) or a nonbreathing bear (NBRB). The baby was monitored by time-lapse video for 3-day periods at the beginning and end of a 2-wk intervention period. The BRB babies decreased their latency to contact the bear over time, whereas the NBRB babies showed the opposite pattern. For the BRB babies, decreased contact latencies were correlated with increased total contact and increased contact frequencies. Thus, by 35 wks CA, premature infants learned to find and make contact with a reinforcing source of stimulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Results of follow-up of mothers with previous surgical "total cervical cerclage" also with reference to neonatal data

From August 16, 1993 until March 6, 1995 a study was conducted at the Department of Obstetrics at the Berlin-Neukoelln Womens Hospital to evaluate the status of patients who had previously undergone total cervical occlusion (TCO) for the prevention of late abortion and premature birth. Special consideration was given to the possible effects of TCO on the patients' gynecologic status, the psychological circumstances associated with TCO and the developmental status of the infants. Fifty-four women participated in the study, their ages ranging between 26 and 53 years. The mean time-span between the TCO procedure and the present study was five years and five months. In the 54 women undergoing TCO, a total of 73 such procedures were performed. An extensive early TCO was performed in 63% and an extensive late TCO in 20.5%. The gestational age at the time of delivery was > or = 37 + 0 weeks in 67.1% of the women. More than half of the patients (54.9%) experienced a normal spontaneous vaginal delivery. In total, 84.5% of the infants were delivered vaginally; thus the cesarean section rate was only 15.5%. Regarding the patients' medical histories, the majority of the patients had no pathological findings on routine pap smears and pelvic examinations and, similarly, they had no complaints of menstrual irregularities. Only 10 patients (18.5%) underwent gynecological surgery in the interim; in these patients, the most common reason for surgery (in four cases) was sterilisation. The findings during speculum examination were tabulated. The majority of the patients (96%) exhibited a normal multiparous cervical portio. In 55% of the patients there was no evidence of scarring of the cervical portio. In 25% of the patients there was minor cervical scarring, in 13.5% it was moderate and in 5.8% it was severe. Except for a single case, the patients showed no evidence of vaginitis. During bimanual palpation on pelvic examination, in 82.7% of the patients the cervix was found to be at least 2 cm in length, a closed external cervical os was palpated in 65.4%, and an anteflexed/anteverted uterus that was normal in size and form was noted in 46.2%. In 95.4% of the patients, original squamous epithelium was seen colposcopically. The psychosocial status of each patient was evaluated on an individual basis. After taking all of the psychosocial circumstances associated with such a high-risk pregnancy into consideration, all the patients giving birth to a living infant described that event as a positive experience. However, this was not the case in the two patients whose premature infants did not survive. In 74.1% of the patients, the relationship with their domestic partners was described as "unchanged" when compared to the status of their relationship during the preceding pregnancy without TCO. The patients undergoing TCO described their own psychological status as "frequently strained" (61.1%) and "disturbed" (9.3%) antepartum. Postpartum, 90.7% of the patients described their psychological status as "good". In total, there were 74 births in the 54 patients included in this follow-up study. Of these 51 (68.9%) were living term infants, one stillborn (1.4%) and 22 (29.7%) premature infants. One infant weighed less than 1.000 grams while 4 (5.3%) weighed between 1.000 and 1.499 grams. Postpartum, 45.5% of the premature infants and 19.6% of the term infants were hospitalized. The primary indications for the transfer of the premature neonates were intensive care, hyperbilirubinemia and adaptation problems. The physical, emotional and mental development was unimpaired in 91.4% of the children. A capability for good social integration was displayed in 95.7% of the children. Based on the current investigation, it may be concluded that the total cervical occlusion procedure has no significant long-term negative effects.     

Interaction of fluorescent probes with membranes of sarcoplasmic reticulum in AMP deamination

Gentamicin and ampicillin were dissolved in an L-amino acid solution especially prepared for newborn infants and infused intravenously over 24 h in 7 babies with serious neonatal surgical problems. Serum concentrations of the antibiotics were maintained rather constant and well above the minimal inhibitory concentration for most bacterial strains. One very sick newborn infant died with overwhelming Klebsiella pneumoniae septicemia. No signs of renal toxicity or ototoxicity were found. The serum amino acids remained within the normal range, except in 1 child with cytomegalovirus infection and liver insufficiency.     

Fathers' and mothers' responses to the faces and cries of normal and premature infants.

32 White, middle-class couples with 5-mo-old infants were shown videotapes depicting infants who were, in turn quiescent, crying, and quiescent. Half of the parents viewed a normal (full-term) newborn, while half viewed a premature infant. Sound tracks were dubbed so that half of the normal and half of the premature infants "emitted" the cry of a normal infant, while the other half emitted the cry of a premature infant. Physiological (heart rate, diastolic blood pressure, and skin conductance) and self-report measures (a mood adjective checklist and an infant temperament measure) were gathered. The cry of the premature infant elicited greater autonomic arousal and was perceived as more aversive than the cry of the normal infant. The effect was especially pronounced when the premature cry was paired with the face of a premature infant. There were few sex differences. Results are discussed with reference to demographic evidence indicating that prematurely born children are "at risk" for child abuse. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Glycogen content in the liver and skeletal muscles in certain types of experimental nanism

The presence of various types of birthmarks was determined in 1,058 newborn infants under 72 hours of age. Of these, 79.5% were white, 6.2% were black, 11.2% were ladinos, and 2.6% were Asiatic. Mongol spots were present in 9.6% of the white babies, 95.5% of the black babies, 81% of the Asiatic babies, and 70.1% of ladino infants. Pigmented lesions were present in 42 (4%) of the infants. Biopsies obtained in 34 (3.2%) revealed that only one-third (11) of these were melanocytic nevi. Salmon patches were present in 40.3% of the infants, recognizable early strawberry marks in 2.6%, and port-wine strains in 0.3%. In addition to birthmarks, it was determined that 30.3% of the 508 babies examined at one of the two hospitals had toxic erythema of the newborn.     

Plasma L-arginine concentration, oxygenation index, and systemic blood pressure in premature infants

OBJECTIVE: To determine the relationships between plasma L-arginine concentrations and the severity of respiratory distress syndrome (RDS) or systemic blood pressure in premature infants. DESIGN: Prospective, observational study. SETTING: Neonatal intensive care, tertiary referral hospital. SUBJECTS: Fifty-three premature infants. INTERVENTIONS: We measured arginine and nutritional intake, plasma arginine concentration, total amino acid concentrations, and blood pressure on days 3, 7, 14, and 21 of life. In 33 infants who received assisted ventilation, oxygenation index could be calculated to reflect the severity of RDS. The relationships between plasma arginine and oxygenation index or blood pressure were analyzed using multiple linear regression. MEASUREMENTS AND MAIN RESULTS: On day 3, plasma arginine concentrations were decreased compared with normal published values. Arginine concentrations increased with the day of life of measurement (p < .001) and with arginine intake (p < .001). After adjusting for arginine intake and day of life, an inverse relationship was found between oxygenation index and plasma arginine concentrations: (p = .025). No similar relationship was found between oxygenation index and the concentration of total amino acids. A weak positive relationship was found between plasma arginine concentration and systemic blood pressure. CONCLUSIONS: Increments in the oxygenation index, reflective of an increased severity of RDS, are associated with a decrease in plasma arginine concentration. This finding may reflect arginine consumption by the nitric oxide synthase pathway in the lungs of premature infants with RDS, or may be explained by increased arginine catabolism. The lack of a similar relationship between total plasma amino acids and oxygenation index supports the first interpretation.     

Mechanisms of the origin of chromosomal aberrations

The most probable factor connecting premature infant problems such as retinopathy, intraventricular hemorrhage and chronic lung disease appears to be the excessive production of oxygen free radicals which can occur as a consequence of oxygen therapy. The aim of our investigation was to elucidate the possible correlations between lipid peroxidation, in this study measured as hydroperoxides production, and antioxidant concentrations in erythrocyte membranes of both full term and preterm infants. Hydroperoxide concentrations were found to be high, especially in premature infants, in erythrocyte membranes at birth and in the initial days of life. The erythrocyte membranes were also found to contain low levels and/or low activities of antioxidant defense mechanisms which was more evident in premature newborns where alpha-tochopherol levels were significantly lower in comparison to full term infant levels. Furthermore, when premature infants undergo oxygen therapy these effects were exacerbated. These results demonstrate that at birth, particularly in the premature newborn, the degree of oxidative stress outweighs the antioxidant defense mechanisms.     

Eosinophilia in newborn infants

To evaluate the clinical significance of eosinophilia in newborn infants, 261 admissions to the neonatal unit over a 12-month period were studied retrospectively; 33 babies with eosinophilia (> 1.0 x 10(9)/l) were studied. Clinical and laboratory data for the first month of life were compared, where available, between gestational age-matched pairs with and without eosinophilia. Of the 33 babies with eosinophilia, 23 were > 26 weeks' gestation and all had age-matched controls; 10 were < or = 26 weeks' gestation but had no appropriate gestational age-matched controls. Babies > 26 weeks' gestation with eosinophilia had a significantly higher number of septic episodes than controls: 20 of 23 versus 4 of 23. All 10 babies < or = 26 weeks' gestation with eosinophilia developed sepsis. Infections with gram-negative organisms and necrotizing enterocolitis occurred only in babies who developed eosinophilia. In 5 babies no cause for the eosinophilia was found. In conclusion, eosinophilia in the newborn is usually explainable and is most often associated with infection.     

Intravenous glucose suppresses glucose production but not proteolysis in extremely premature newborns

To ascertain whether the inability to suppress glucose production and increase glucose utilization in response to glucose infusion is an inherent characteristic of immature individuals, we determined glucose rate of appearance (R(a)) in minimally stressed, clinically stable, extremely premature infants (approximately 26-wk gestation) at two glucose infusion rates (6.2 +/- 0.4 and 9.5 +/- 0.5 mg/kg per min). We also assessed whether an increase in glucose delivery suppresses proteolysis by measuring the R(a) of phenylalanine and leucine. Glucose R(a) (and utilization) increased significantly at the higher glucose infusion rate (7.9 +/- 0.5 vs. 9.8 +/- 0.6 mg/kg per min). Glucose production persisted at the lower glucose infusion rate but was suppressed to nearly zero at the higher rate (1.7 +/- 0.5 vs. 0.3 +/- 0.1 mg/kg per min). Proteolysis was unaffected by the higher glucose infusion rate as reflected by no change in the rates of appearance of either phenylalanine (96 +/- 5 vs. 95 +/- 3 mumol/kg per h) or leucine (285 +/- 20 vs. 283 +/- 14 mumol/kg per h). Thus, clinically stable, extremely premature infants suppress glucose production and increase glucose utilization in response to increased glucose infusion, demonstrating no inherent immaturity of these processes. In contrast, increasing the rate of glucose delivery results in no change in whole body proteolysis in these infants. The regulation of proteolysis in this population remains to be defined.     

Anemia and red cell distribution width at the 12-month well-baby examination

BACKGROUND: Screens for anemia are among the most commonly done laboratory tests in children. The red cell distribution width (RDW) has been proposed as a diagnostic aid in the evaluation of pediatric anemias, but no prospective studies have been published describing its use. METHODS: A screening hematocrit determination done at the 12-month well-baby examination in 970 healthy infants yielded 62 low values (< 33%), 31 of which were confirmed by heel stick complete blood count (CBC). After a 1-month trial of iron therapy, those with a rise in hemoglobin of at least 1 g/dL were considered to have iron-deficiency anemia. Nonresponders, after review of clinical and laboratory data (CBC, lead screen, and sickle screen), had hemoglobin electrophoresis if indicated. RESULTS: Abnormalities detected were iron deficiency, alpha-thalassemia, and hemoglobins SC and AS. These conditions were detected in 9 of 11 infants with abnormal RDW and none of 9 with normal RDW. CONCLUSIONS: The RDW alone appears to be predictive of identifiable causes of anemia when used in screening 12-month-old babies who are otherwise healthy.     

Cerebrospinal fluid amino acid levels in newborn infants with intracranial hemorrhage

Cerebrospinal fluid (CSF) amino acid levels including excitatory amino acids (i.e. glutamate and aspartate) in 25 preterm and 18 full-term newborn infants with no serious disease except intracranial hemorrhage (ICH) were measured. ICH was detected in 13 preterm and six full-term infants on the basis of the clinical, lumbar puncture (LP) and cranial ultrasonography (CraUSG) findings. Twelve preterm and 12 full-term infants who were neurologically healthy comprised the control group. The mean concentration of CSF amino acids did not differ between preterm and full-term infants. The CSF concentrations of taurine, threonine, glycine, alanine, valine, isoleucine, leucine, tyrosine and phenylalanine in preterm infants, and threonine, aspartic acid and alanine in full-term infants were significantly elevated in infants with ICH. These abnormalities, especially in preterm infants, are probably related to cerebral hypoxia in CSF amino acid concentrations in newborn infants with ICH.