bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Thyroxine on the Transmission of Immunoglobulin across the Small Intestine of Young Rats
Authors: Jones R.E.
Published: September 2009

Evidence is presented of a relationship in young rats between thyroxine, intestinal digestion, and the ability of these animals to absorb immunoglobulin across the gut. Administration of thyroxine resulted in a marked reduction of IgG transport into the circulation. The period of decreasing absorption coincided with a period of increased efficiency of the digestive system in particular to the increased levels of cathepsin B in the intestinal wall.
Effects of Fat-Free Diet on Fetal and Maternal Glucose-6-Phosphate Dehydrogenase and the Timing of Parturition in the Mouse
Authors: Dresser Betsy L. , Russell Paul T. , Ludwick Thomas M.
Published: September 2009

Pregnant mice were fed a fat-free diet during the first 17 days of pregnancy with fatty acid compositions and glucose-6-phosphate dehydrogenase activities measured in maternal and fetal liver and in placenta. Both liver and placenta showed fatty acid composition typical of essential fatty acid deficiency. The glucose-6-phosphate dehydrogenase activity increased 10-fold in maternal liver, but no diet-induced change in placental or fetal liver glucose-6-phosphate dehydrogenase activity was seen. The maternal arachidonic acid stores were not sufficiently depleted by fat deprivation to alter the course of pregnancy or parturition.
Evaluation of Renal Function in Neonatal Rats
Authors: Kavlock Robert J. , Gray Jacqueline A.
Published: September 2009

The ontogenetic profile of several parameters of neonatal renal development in the rat is presented. Nephrogenesis was observed to continue at a rapid pace between birth and 8 days of age and to be virtually complete by 11 days of age. The activity of alkaline phosphatase, a brush border enzyme, declined during this time period relative to organ growth as a whole. The ability to elaborate a concentrated urine when presented with a period of fluid deprivation was barely present at birth and increased dramatically with age. Finally, the diuresis response to an orally administered water load was detected on the second postnatal day, while the response to antidiuretic hormones was present to a slight degree on the first postnatal day.
Pulmonary Excretion Rates of Carbon Monoxide Using a Modified Technique: Differences between Premature and Full-Term Infants
Authors: Cohen Ronald S. , Ostrander Clinton R. , Cowan Barrett E. , Stevens Gloria B. , Hopper Andrew O. , Stevenson David K.
Published: September 2009

The pathophysiology of the exaggerated hyperbilirubinemia in premature infants remains unclear. The relative contribution of bilirubin production may be estimated by measuring the pulmonary excretion rate of carbon monoxide (VeCO) We found that the mean Veco of premature infants, 16.7 ± 5.0 μl/kg/h, was significantly elevated (p < 0.05) compared with the mean VeCO of full-term infants, 13.9 ± 3.5 μl/kg/h. Premature infants who required phototherapy had a significantly (p < 0.05) higher mean VeCO than those who did not. The VeCO did not correlate with gestational age, implying that factors which associate frequently but variably with gestational age may have an important influence on heme catabolism.
Secretin Levels in Plasma and Tissue of the Neonatal Swine
Authors: Moazam F. , Rodgers B.M. , Wheeldon S. , Kolts B.E.
Published: September 2009

The mean fasting serum secretin level determined in newborn swine was found to be 298.0 ± (SEM) 5 pg/ml, significantly higher than that in the adult animal. Intraduodenal infusion of 0.1 N HCI produced dramatic elevation of the mean serum secretin level to 2,090 ± 340 pg/ml. The tissue secretin concentration of duodenal mucosa as well as the molecular species of tissue secretin were found to be identical to that of the adult swine. The mean disappearance half-life of exogenously administered secretin in the newborn swine was significantly prolonged over adult values, to 3.6 min. These data suggest that delayed secretin degradation can be implicated as a factor in the etiology of the hypersecretinemia in the newborn swine.
Normal Arterial Blood Pressure in the Nephrectomized Fetal Lamb
Authors: Binder Nancy D. , Anderson Debra F. , Potter Mark , Thornburg Kent L. , Faber Job
Published: September 2009

Arterial blood pressures in 18 lambs who had been nephrectomized 3–24 days before were not significantly different from those of 26 control fetuses or from those of control fetuses in the literature. Plasma renin activities were below the detection level of our assay. The nephrectomized fetuses continued to grow according to a variety of indices. We concluded that neither the kidney nor the renin angiotensin system are necessary for the long-term regulation of fetal blood pressure, probably because of their inability to affect placental exchange of water and electrolytes.
Perinatal Changes in Mitochondrial Respiration of the Rabbit Heart
Authors: Werner John C. , Whitman Victor , Musselman Jude , Schuler Gregg
Published: September 2009

Oxidative metabolism and citrate synthase activity during the perinatal period were assessed in isolated rabbit heart mitochondria at 27 days’ gestation (27 dpc), 1 day postpartum (1 dpp) and 10 dpp. Oxygen consumption was measured during state 3 and state 4 respiration using the following substrates: glutamate, α-ketoglutarate, pyruvate/malate, succinate/rotenone, acetate, palmitylcarnitine, and palmityl CoA/carnitine. Results obtained from fetal and neonatal animals were compared to values obtained from adult left and right ventricles. Rates of state 3 oxygen consumption per milligram mitochondrial protein using tricarboxylic acid cycle intermediates or palmitylcarnitine were higher in both 1 and 10 dpp animals than in either left or right ventricles. Respiratory activity per milligram mitochondrial protein using these substrates was similar in 27 dpc fetuses and adult left ventricles. The rate of oxidation of palmityl CoA was lower in fetal mitochondria than in adult left ventricle, indicating that the capacity for conversion of long-chain fatty acyl CoA to acylcarnitine necessary for transport of fatty substrates into the mitochondria is decreased in fetal hearts. Increases in myocardial citrate synthase corresponded to increases in mitochondrial mass reported by other investigators.
Effect of Somatostatin on Basal Concentrations of Gastrin and Pancreatic Polypeptide in the Fetal Sheep
Authors: Shulkes Arthur , Hardy Kenneth J.
Published: September 2009

The effect of somatostatin infusion on basal plasma gastrin and pancreatic polypeptide (PP) has been examined in the chronically cannulated fetal sheep and in adult sheep. Somatostatin decreased basal gastrin and PP in the fetal sheep. Similar changes were seen in the adult sheep. A rebound of gastrin and PP above control levels occurred when the somatostatin infusion ceased in the adult, but this rebound was not seen in the fetus, probably from the absence of a fetal acid-gastrin feed back loop. The data is compatible with the hypothesis that in the fetus, the low plasma levels of gastrin and PP in mid-gestation are from the inhibition of their secretion by somatostatin.
Echinocytic Sensitivity and Deformability of Human Newborn Red Cells
Authors: Coulombel L. , Tchernia G. , Feo C. , Mohandas N.
Published: September 2009

Echinocytic red cells are present in the peripheral blood of normal human newborns in small but significant numbers. This is in contrast to normal adults in whom no echinocytes are found in peripheral blood. In addition, red cells from newborns have increased susceptibility to echinocyte transformation induced by naturally occurring phospholipid lysolecithin. The mechanism for this increased susceptibility does not appear to be related to the lipid composition of these cells. Cellular deformability of red cells from newborns, as determined by a newly developed viscodiffractometric technique, is similar to that of adult red cells. This finding differs from an earlier report of reduced deformability of fetal red cells.
Transient Respiratory Difficulty following Cesarian Delivery
Authors: Patel Daksha M. , Donovan Edward F. , Keenan William J.
Published: September 2009

57 newborn infants delivered by planned, repeat cesarian section were studied to determine the role of surfactant in transient neonatal respiratory distress. 22.8% of the newborn infants studied had transient tachypnea of the newborn. The mean amniotic fluid lecithin-sphingomyelin ratio (L/S) was 2.8 in normal infants and 2.6 in infants with transient tachypnea. The mean gastric aspirate L/S at the time of delivery was 3.0 in the normal infants and 2.7 in infants with transient tachypnea. There were no statistically significant differences in either amniotic fluid L/S or gastric aspirate L/S. Based on these results we speculate that, despite altered lung mechanics in neonates with transient tachypnea, lung maturity as determined by L/S ratio does not differ from that of normal neonates.
C-Peptide Levels in Amniotic Fluid in Experimental Fetal Growth Retardation
Authors: De Prins F. , Van Assche A. , Milner R.D.G.
Published: September 2009

Ligation of the uterine vessels in pregnant rats leads to reduced concentrations of C-peptide in the amniotic fluid. The reduced C-peptide levels reflect an impaired fetal insulin secretion. This may be one of the mechanisms of pathogenesis of intrauterine growth retardation in the presence of a deficient maternoplacental supply line to the fetus.
Development of NADPH-Consuming Pathways in Heart, Brain and Liver of the Rat
Authors: Andrés Antonio , Satrústegui Jorgina , Machado Alberto
Published: September 2009

The behavior of the principal NADPH-consuming pathways, fatty acid synthesis (-ATP-citrate lyase), transhydrogenase, glutamate dehydrogenase, glutathione reductase, NADPH-cytochrome c reductase and mitochondrial and cytoplasmic thioredoxin reductases were studied during the development of the heart, brain and liver of the rat. The liver is the tissue with highest NADPH-consuming activities. Transhydrogenase activity is highest in the heart; it undergoes two steep increases of activity, one at birth and another between 15 and 25 days. Liver cytoplasmic glutathione reductase activity increases mainly at birth. The activities in heart and brain are lower and the brain enzyme activity slightly increases throughout development. Liver NADPH-cytochrome c reductase activity greatly increases at weaning. The heart activity is the lowest, no changes taking place in the developmental period. Heart mitochondrial and brain cytoplasmic thioredoxin reductases undergo increases in activity at birth. The ratios of NADPH-producing/NADPH-consuming activities are constant in all tissues studied, and oscillate between ≃4 in fetuses to ≃2 in adults, the only exception being the adult heart ratio (≃23). This otherwise constancy confirms that both processes are closely correlated.
Sites of Action of Light during Phototherapy
Authors: Granati Bruno , Felice Michele , Fortunato Antonio , Giancola Giuseppe , Rubaltelli Firmino F.
Published: September 2009

In order to investigate the main sites of action of phototherapy in the treatment of neonatal jaundice we studied (a) the in vivo and in vitro relationship between the hematocrit and the effectiveness of phototherapy, and (b) the effect of varying the skin area exposed to light. The results show that the hematocrit does not influence in vivo the efficacy of phototherapy, while they confirm that the total skin surface exposed to light is important in determining the effectiveness of light treatment. The authors have also studied the possible action of phototherapy on bilirubin solutions placed into the postmortem brain or the stomach. The results suggest that blue light does not penetrate strongly enough to photomodify the exposed pigment.
Developmental Changes in Fetal Adrenal Hypertrophy following Maternal Bilateral and Fetal Unilateral Adrenalectomy at Different Stages of Gestation in the Rat
Authors: Yamamoto Masako , Eguchi Yasunobu , Asari Masao , Kano Yutaka
Published: September 2009

Maternal adrenalectomy on days 14 and 15 of gestation did not alter the fetal adrenal weight 2 days later. The same operation on day 16 caused a significant increase in the adrenal weight with a hypertrophy of the cortical cells. Nevertheless, the operation on days 17 and 18 induced no change in the fetal adrenals. Subsequently on days 19 and 20, the operation resulted in a significant hypertrophy of the fetal adrenals. Fetal unilateral adrenalectomy on day 18 caused, 2 days later, significant hypertrophy of the contralateral adrenal, in contrast with no significant change after maternal adrenalectomy. This is perhaps due to the difference in the amount of fetal plasma corticoids, as evidenced by the previous reports of high concentrations of fetal plasma corticosterone on days 19 and 20. The overall results suggest that the fetal pituitary-adrenal feedback mechanism begins to appear between days 16 and 18 of gestation.
Cardiovascular Effects of Dopamine in Developing Swine
Authors: Buckley N.M. , Brazeau P. , Frasier I.D.
Published: September 2009

Cardiac function and peripheral blood flows were measured before and during single intravenous injections of dopamine (2–25 μg/kg) in developing and mature swine anesthetized with pentobarbital. A positive inotropic effect was observed in even the youngest swine. Renal vasoconstriction was observed even after low doses of dopamine in animals younger than 1 month of age, and femoral vasoconstriction in animals younger than 2 weeks of age, unless α-adrenergic receptors were blocked by phentolamine. We concluded that the vasodilator responses to dopamine are slower to develop in the renal than in the femoral circulation.
Patterns of Monoamine Oxidase Maturation in Mouse Brain
Authors: Baker Peter C. , Hoff Kenneth M. , Samsa Joseph M.
Published: September 2009

Monoamine oxidase (MAO) was assayed in mouse brain between the ages of 1 day postpartum and adulthood. Two substrates, 5-hydroxytryptamine (5-HT) and tryptamine, were used and assays were done with and without thermal inactivation at 50 °C for 10 min. Relative patterns of MAO maturation were found including one form that decreased with increasing age.
Benzodiazepine Receptors in the Human Fetus
Authors: Aaltonen Leena , Erkkola Risto , Kanto Jussi
Published: September 2009

The existence of benzodiazepine receptors in the human fetal brain, liver and placenta has been studied. At 12–15 weeks of gestation specific binding to fetal brain occurs. The dissociation constant of [3H]-flunitrazepam-specific binding was 1.5–2 nM and the maximum number of binding sites was 2.3–3.8 fmol/mg of total brain tissue. In the fetal liver and placenta some specific binding exists, yet the nonspecific binding is more extensive.
Cardiac Output and Organ Blood Flow in Young Rabbits during Intermittent Positive-Pressure Ventilation
Authors: John Elizabeth , McDevitt Michael , Cassady George
Published: September 2009

Cardiac output and organ blood flow were measured by a microsphere technique in three groups of healthy young rabbits. In one group, animals were subjected to light sedation and intermittent positive-pressure ventilation. Control animals in a second group were sedated but not ventilated. In a third group, animals were conscious and breathing spontaneously. Cardiac output increased significantly (p < 0.05) in conscious controls and in one measurement in anesthetized controls. It did not change in ventilated rabbits. Blood flow to the brain increased during study in all three groups and to the eye in both control groups. These elevations in cardiac output and cerebral blood flow were attributed to arousal. Blood flow to the kidney decreased in both anesthetized groups. The blood flow to skin, muscle, ileum and colon decreased significantly in the ventilated animals though not in the anesthetized controls. In both groups, similar reductions were found in the fractional distribution of cardiac output to these areas. It was concluded that ventilation at low pressure had no effect on cardiac output. The occurrence of redistribution of the circulation was deduced from the parallel reductions of regional blood flows and fractions of cardiac output received by some organs together with preservation of cerebral blood flow, though it was obscured in the two control groups by simultaneous increases in cardiac output. The circumstances suggested that this redistribution was due to disturbed homeostasis from arousal. Implications for the newborn were discussed.
Serum Copper and Zinc Levels in the Preterm Infant
Authors: McMaster Dorothy , Lappin T.R.J. , Halliday H.L. , Patterson C.C.
Published: September 2009

Serial determinations were carried out on 27 male and 21 female preterm infants (gestational age 28–36 weeks) throughout the first year of life. Serum copper at birth was 0.33 ± 0.20 μg/ml (n = 8); at 9 weeks, 0.77 ± 0.19 μg/ml (n = 22); at 24 weeks, 1.00 ± 0.27 μg/ml (n = 31), and at 52 weeks 1.21 ± 0.27 μg/ml (n = 40). Serum zinc at birth was 1.03 ± 0.16 μg/ml (n = 9); at 9 weeks, 0.71 ± 0.11 μg/ml (n = 17); at 24 weeks, 1.02 ± 0.20 μg/ml (n = 20), and at 52 weeks, 1.19 ± 0.34 μg/ml (n = 33). The results of this study compare well with values previously reported for infants studied at selected age points.
Cholesterol Synthesis in the Small Intestine and Adipose Tissue of Suckling Rats: The Effect of Litter Size
Authors: Kroeger S. , Hahn P.
Published: September 2009

Rats were raised in large (14/dam), medium (8/dam) and small (4/dam) litters. The rate of in vitro synthesis of cholesterol from 3H2O in the proximal and distal parts of the small intestine decreased from birth to a low 14 days later and then increased again by day 21. The rate of synthesis in both parts of the gut on day 6 after birth was lowest in the 14/dam group. On day 21 after birth the rate was highest in the 14/dam group in the proximal and lowest in the distal gut. Thus in the early postnatal period low rates of intestinal cholesterol synthesis correlate with low plasma cholesterol values. In white adipose tissue the low rate of cholesterol synthesis remained unaltered up to day 21 in the 8/dam, and 4/dam groups. However, it continuously increased in the 14/dam group being about threefold higher than in the other two groups on day 21.
Conversion of Choline to Phosphatidylcholine in the Isolated-Ventilated-Perfused Neonatal Rabbit Lung
Authors: Zachman Richard D. , Cotter Patrick W. , Tsao Francis H.C.
Published: September 2009

The isolated-ventilated-perfused neonatal rabbit lung model was used to study pulse dosed 14C-choline incorporation into 14C-phosphatidylcholine (PC) and 14C-disaturated phosphatidylcholine (DSPC). 14C-PC and 14C-DSPC synthesis were linearly dependent upon perfusion time to 30 min and upon the pulse dose of 14C-choline of 20–250 nmol at both 10 and 30 min of perfusion. 2–3% of the pulse-dosed choline was taken up by the lung. The water-soluble metabolites of choline found in lung after 10–30 min of perfusion were: choline, 50–60%; betaine 2.4–3.0%; phosphorylcholine, 26–41%, and CDP-choline, trace-10%. 1-day-old perfused lungs incorporated pulse-dosed 14C-choline into 14C-PC and 14C-DSPC at slightly higher rates than at 10 days old. Newborn rabbits receiving an intraperitoneal injection of 0.1 mg dexamethasone/100 g body weight 16 and 22 h prior to perfusion incorporated significantly more 14C-choline into l4C-PC and 14C-DSPC than saline-injected controls.
Plasma Amino Acid Ratio as an Index of Hepatocellular Maturity in the Neonate
Authors: Glasgow J.F.T. , Moore R.
Published: September 2009

A preprandial plasma amino acid molar ratio [(isoleucine + leucine + valine)/(tyrosine + phenylalanine)] has been studied in 33 neonates of mean gestation approximately 34 weeks. 19 infants were fed a formula containing 2.5 g protein/dl with a high casein content (group 1), whilst 14 received milk of 1.8 g protein/dl largely derived from whey. Although total amino acid levels were significantly higher in group 1 (p < 0.001), the amino acid molar ratio was similar in each group. This ratio correlates directly with gestational age (r = +0.76; p < 0.0001) which, on multiple regression analysis, accounted for 57% of its variability. The effects upon the ratio of infant’s sex, cholestasis, and hepatic enzyme induction are also discussed.
Reduced Renal Mass in Early Postnatal Development
Authors: Chevalier Robert L.
Published: September 2009

As shown previously in the neonatal guinea pig, unilateral nephrectomy at birth results in an earlier rise in superficial nephron glomerular filtration rate. To evaluate the role of glomerular dynamics in this compensatory adaptation, pressure gradients responsible for glomerular ultrafiltration in superficial nephrons were measured by micropuncture techniques in developing euvolemic guinea pigs subjected to uninephrectomy or sham operation at birth. Uninephrectomy resulted in a significant rise in mean arterial blood pressure and glomerular capillary pressure by 10 days of age. Effective filtration pressure was 30% higher in 10- and 21 -day-old uninephrectomized guinea pigs compared to sham-operated littermates. However, there was no significant increase in effective filtration pressure with normal growth from 10 to 21 days of age. Augmented pressure gradients for glomerular ultrafiltration therefore contribute significantly to early compensatory renal adaptation but not to the transitional sharp increase in superficial glomerular filtration which characterizes normal renal growth from 10 to 21 days of age. The apparent acceleration of functional glomerular maturation resulting from uninephrectomy at birth may result from the summation of differing responses to the demands of somatic growth and reduced renal mass.
Synergistic Effects of Insulin and Thyroxine on the Differentiation and Proliferation of Epithelial Cells of Suckling Mouse Small Intestine
Authors: Malo Christiane , Ménard Daniel
Published: September 2009

The interactions between insulin, cortisone and thyroxine on the functional maturation of the small intestine were investigated. 8-day-old suckling mice received one injection/day during 3 days of a single hormone or of the following hormonal combinations: insulin plus cortisone or insulin plus thyroxine. The differentiation of intestinal epithelial cells was evaluated by measuring brush border membrane hydrolytic activities and proliferation by establishing the mitotic index and 3H-thymidine incorporation into DNA. The effects of cortisone and insulin on enterocyte’s differentiation are additive. Thyroxine accelerates the differentiation and has a limited action on cell proliferation. Insulin exerts a sustained effect on these two aspects of the intestinal maturation and, furthermore, acts in synergism with thyroxine. It appears that insulin, cortisone and thyroxine have their own specific effect on differentiation and proliferation of the epithelial cells and that these three hormones act in cooperation to induce the maturation of the suckling mouse small intestine during postnatal development.
Arterial Cord Blood Hypoxanthine: A Measure of Intrauterine Hypoxia?
Authors: Lipp-Zwahlen Anna Elisabeth , Tuchschmid Peter , Silberschmidt Monica , Duc Gabriel
Published: September 2009

In order to evaluate the concentration of hypoxanthine in the cord blood as an indicator of intrauterine hypoxia, hypoxanthine was determined in the arterial and venous cord blood of 49 randomly chosen newborns and in the peripheral venous blood of their mothers. In addition, 5 young, nonpregnant women were investigated. Term babies with signs of probable intrauterine hypoxia (fetal distress, scalp blood or arterial cord blood pH < 7.19, and/or Apgar score of < 5 at 1 min) had hypoxanthine levels (19.8 ± 3.5 μmol/l) consistently above the mean for normals. However, there was a large variability of hypoxanthine values in normal babies (16.1 ± 5.7 μmol/l) and in those with isolated signs of fetal distress (14.6 ± 6.9 μmol/l). There was no general correlation between the levels of hypoxanthine in arterial cord blood and arterial cord blood pH (r = -0.15) or between the levels of hypoxanthine in arterial cord blood and the Apgar score at 1 min (r = -0.05). At delivery, all mothers had higher levels of hypoxanthine than nonpregnant women (16.0 ± 6.8 vs. 7.6 ± 2.1 μmol/l; p < 0.001). The maternal hypoxanthine values correlated closely with those of the venous cord blood (r = 0.72; p < 0.001). Positive arterio-venous differences in the cord blood increased with progressively higher levels of hypoxanthine in arterial cord blood (r = 0.53; p < 0.001), indicating a clearance through the placenta. The frequently observed negative arterio-venous difference (37 % of all cases) indicates a passage of hypoxanthine from the mother to the baby as well. We conclude: (1) high levels of hypoxanthine in the cord blood probably depend only in part on hypoxia; (2) hypoxanthine equilibrates bidirectionally across the placenta. Therefore, the levels of hypoxanthine found in neonatal cord blood do not provide reliable evidence of intrauterine hypoxia.
Effect of Liquid Ventilation on Preterm Lamb Tracheal Mechanics
Authors: Bhutani Vinod K. , Shaffer Thomas H.
Published: September 2009

Liquid ventilation with fluorocarbon has been demonstrated as a viable mode of ventilatory support to preterm or distressed lambs. The effect of liquid ventilation and its high inflation pressures in proximal airways was evaluated on the mechanical behavior of the preterm trachea. 7 preterm lambs (134 ± 1.5 SE days of gestation; 90% term) were ventilated with fluorocarbon (Rimar) for 58.6 ± 8 min. The tracheae were dissected and the ventilated, distal segments were compared to nonventilated proximal segments. Pressure-volume curves were determined by plethysmography and specific tracheal compliance was computed. Tracheal dimensions increased 13.6 and 25.6% in diameter and volume (p < 0.05), respectively, and the compliance decreased 29.9% (p < 0.05). The magnitude of these changes is comparable to that observed during gaseous ventilation of term animals.
Development of Enzymes of Energy Metabolism in Rat Heart
Authors: Andrés A. , Satrústegui J. , Machado A.
Published: September 2009

The behavior of several enzymes was studied during rat heart development (4 days before birth to adult stage). Hexokinase has its highest activity during the fetal period; it decreases at birth and remains with low activity in the adult. The α-glycerophosphate dehydrogenase and α-glycerophosphate oxidase profiles are similar up to the 15th day of development. From there onwards, both profiles diverge, the cytoplasmic activity increasing 3-fold, while the mitochondrial activity remains unchanged. The developmental profiles of the malate dehydrogenases are almost parallel. The development of citrate synthase and succinate dehydrogenase results in a 2- to 4-fold increase in their activities. However, ATPase increases dramatically (20-fold) over the same period. With respect to the enzymes of the adenine nucleotide metabolism, adenylate kinase is fully expressed throughout all ages examined, showing no variation during development. AMP deaminase and creatine kinase increase during development, the cytoplasmic creatine kinase reaching a high level at birth whereas the increases of the mitochondrial enzymes take place gradually during development.
Bacterial Endotoxins in Umbilical Cord Blood of Neonates
Authors: Scheifele David W. , Fussell Susan , Olsen Edna
Published: September 2009

We tested umbilical cord blood from 255 infants for evidence of bacterial endotoxins. Using a Limulus lysate gelation technique, endotoxin-like activity (ELA) was detected in 13 (9.1%) of 142 term infants and in 23 (20.3%) of 113 preterm infants (p < 0.05), in concentrations ranging from 30 to 3,000 pg Escherichia coli equivalent activity per milliliter of plasma. No factors predisposing to endotoxemia could be detected in term pregnancies but among ELA+ premature infants, placental cultures more frequently revealed gram-negative species (p < 0.05). Cord blood endotoxemia in the concentrations observed was without obvious consequence in mothers and term infants. Our data confirm the existence of natal endotoxemia, a potential mechanism of perinatal injury.
Evidence that Hepatic Mitochondrial Mass Decreases during the First Sixteen Hours following Birth in Starved Newborn Rats
Authors: Escrivá F. , Decaux J.F. , Ferré P. , Girard J.R.
Published: September 2009

Fatty acid oxidation increases in newborn rats between 0 and 16 h after birth. We have tested the hypothesis that such a rise might be due to an increase in hepatic mitochondrial mass. The ratio total activity/specific activity for cytochrome c oxidase and citrate synthase was used as an index that reflected the changes in mitochondrial mass. This ratio was decreased by about 25% 16 h after delivery, indicating that hepatic mitochondrial mass was lower 16 h after birth than at birth in starved rats. We conclude that changes in the mitochondrial mass are not responsible for the increase in liver capacity to oxidize fatty acids.
Energy Metabolism and Relative Brain Size in Human Neonates from Single and Multiple Gestations
Authors: Hofman Michel A.
Published: September 2009

From an allometric analysis of single and multiple human pregnancies the metabolic rate and the degree of encephalization of neonates could be calculated. As a result of the reduction in somatic growth in multiple gestations the oxygen consumption per neonate was found to be an inverse non-linear function of litter size. Furthermore, differential growth rates between brain weight, body weight, and body length, respectively, in the late prenatal period revealed that twins at birth are in general less encephalized than are newborns from single births.
Plasma Amino Acids of the Mid-Trimester Human Fetus
Authors: McIntosh N. , Rodeck C.H. , Heath R.
Published: September 2009

The amino acid concentrations in umbilical cord plasma taken at fetoscopy were measured from 12 fetuses between 18 and 29 weeks gestation. Concurrent maternal plasma levels were measured. Fetal plasma showed consistently higher concentrations of plasma amino acids with the ratios varying between 1.1:1 and 3:1 and the difference always reached statistical significance. It is suggested that these results reflect the in vivo situation of the mid-trimester human fetus.
Perinatal Development of the Lung in Rat and Spiny Mouse: Its Relation to Altricial and Precocial Timing of Birth
Authors: Oosterhuis W.P. , Mooren P.G. , Charles R. , Lamers W.H.
Published: September 2009

Rat and spiny mouse (Acomys cahirinus) are closely related murinoid species that represent altricial (rat) and precocial (spiny mouse) modes of development. The late intrauterine developmental stages of the spiny mouse therefore seem comparable to the early extra-uterine developmental stages of the rat. To elucidate the question to what extent the development of the lung is related to the developmental timing of birth, we have studied some enzymes involved in the de novo synthesis of phosphatidylcholine. Of the enzymes studied, cholinephosphate cytidylyltransferase shows peaks in activity in the perinatal period (rat and spiny mouse) and at the beginning of the 3rd postnatal week (rat only). This enzyme fulfils the requirements for a developmental parameter best as changes in activity of this enzyme can be correlated with phases of cell proliferation and surface expansion in the lung of the rat. The single peak of cholinephosphate cytidylyltransferase activity in the spiny mouse as well as microscopical examination of the lung support the hypothesis that the processes of proliferation and surface expansion, which occur consecutively in the rat, develop concurrently in the spiny mouse.
The Effects of Myometrial Activity on Fetal Thoracic Dimensions and Uterine Blood Flow during Late Gestation in the Sheep
Authors: Harding R. , Poore E.R.
Published: September 2009

We wished to investigate mechanisms by which non-labour contractions of the uterus influence fetal sleep states and respiratory activity during late pregnancy. The relationship between the dimensions of the fetal chest and uterine contractions was examined in 5 pregnant sheep. The dorso-ventral dimension at the level of the xiphisternum (3 fetuses) decreased, on average by 4.4–9.4% while increases of 16.6–18.7% were seen in the transverse dimension (4 fetuses). Blood flow in a middle uterine artery was monitored using a Doppler technique in 5 pregnant sheep. Non-labour uterine contractions were accompanied by mean reductions of 6.5–12.7% in blood flow. Postural adjustments by the ewe also influenced uterine blood flow. A mean increase in blood flow of 5.9–12.0% followed a change from standing to lying; standing caused a mean reduction of 5.9–11.8%. We conclude that the influence of uterine contractions on the fetus is likely to be complex, involving distortion of the body and alterations in utero-placental haemodynamics.
Human Fetal Weight and Placental Weight Growth Curves
Authors: Bonds Duane R. , Mwape Bwalya , Kumar Savitri , Gabbe Steven G.
Published: September 2009

A mathematical analysis of human fetal and placental growth curves was made on data collected prospectively from a population at sea level. Both the fetal and placental growth curves can best be described by a form of the logistic equation inhibited growth model. The fetal growth rate reaches its maximum approximately 4 weeks after the placental growth rate has reached its maximum. Growth rate constants were calculated for several populations at various altitudes.
Value of Leukocyte Alkaline Phosphatase and Other Leukocyte Parameters in Diagnosis of Neonatal Infection
Authors: Paul Ravinderjeet S. , Kumar Ashir
Published: September 2009

Various leukocyte parameters, i.e., leukocyte alkaline phosphatase (LAP) activity, absolute segmented polymorphonuclear count (segs), absolute band count and bands/segs ratio were studied in 15 full-term newborns with bacterial infections, 15 full-term newborns with bacterial infections, 15 full-term newborns with viral illnesses, and 10 age- and weight-matched control newborns. Mean LAP scores were 87.5 in the control group, 160.3 in newborns with viral illnesses, and 232.7 in newborns with bacterial infections. The differences between each group were statistically significant. The mean band count and bands/segs ratio were 65.6/mm3 and 0.013 in the control group; 842/mm3 and 0.18 in newborns with viral illnesses, and 2,207/mm3 and 0.37 in newborns with bacterial infections. LAP was more sensitive than other parameters in distinguishing the three groups. The data indicate that an LAP score of > 200, a band count of > 500/mm3 and a bands/segs ratio of > 0.3 are highly suggestive of bacterial infection.
Comparison of 2,3-Diphosphoglycerate Metabolism between Fetal and Postnatal Pig Red Cells
Authors: Watts Richard P. , Kim Hyun Dju
Published: September 2009

A four-fold increase in red blood cell 2,3-diphosphoglycerate (DPG) levels occurs within 1–2 weeks after birth resulting in a decrease in oxygen affinity in the newborn pig. In this study, we found that although newborn pig red blood cells seem to be equally capable of net DPG synthesis as adult pig cells when challenged by a mixture of inosine, pyruvate and phosphate, the cells from newborns degrade DPG much faster than do cells from adults. As a result, DPG levels in the newborn’s cells do not seem to increase in comparison to the adult’s cells. Using a density centrifugation technique, it was found that the postnatal cells initially entering the circulation have a relatively low rather than high DPG content. However, DPG content quickly increases as they age. These findings suggest that the rapid rise of DPG seen in the growing piglet is brought about in part (a) by an elimination of the fetal cells with low DPG, and (b) by an emergence of postnatal cells having the capacity to augment their DPG content while in circulation.
Effect of Colostrum Intake on Metabolic Rate and Plasma Glucose in the Neonatal Pig in Relation to Environmental Temperature
Authors: Le Dividich J. , Noblet J.
Published: September 2009

The effects of feeding sow colostrum on oxygen consumption (VO2), heat production (HP), respiratory quotient (RQ) and rectal temperature (RT) were examined in 26 newborn piglets in a thermoneutral (32 °C) and in a cold (18 °C) environment. Colostrum (32 g/kg body weight) was given by gavage at 3 h of age. A control group received a similar amount of saline. VO2 HP, RQ and RT were measured for approximately 1 h prior to force-feeding and 2 h after feeding. The response of plasma glucose to ingestion of colostrum or saline was recorded in 18 additional piglets kept at 32 or 18 °C. The effects of feeding saline on all parameters studied were not significant (p > 0.10). Ingestion of colostrum was followed at both temperatures by a marked rise (p < 0.05) in VO2 and RT. The responses of VO2 were curvilinear (p < 0.05) with the maximum rise occurring in both treatments within 30 min after colostrum administration and amounting (% of prefeeding values) to 45 ± 7 and 16 ± 2% at 32 and 18 °C, respectively. The rises in VO2 persisted for more than 1 h postfeeding. The heat increment associated with feeding colostrum was lower (p < 0.05) at 18 than at 32 °C. Nonsignificant transient increases in RQ were observed. Prefeeding plasma glucose was higher (p < 0.05) at 18 than at 32 °C. At both 32 and 18 °C, the response of plasma glucose to colostrum feeding was curvilinear (p < 0.05), with a similar maximum increment (1.6 ± 0.2 mM/l) occurring at 15–30 min postprandially. Results of this study suggest that the postprandial rise in HP contributes to the maintenance of body temperature of the neonatal pig. The increase in heat production associated with feeding and cold exposure would be mainly caused by an increased supply of carbohydrate to the heat-producing tissues.
Relationship of Unbound Bilirubin Concentration to Reserve Albumin-Binding Concentration for Bilirubin in Human Neonatal Plasma
Authors: Karp Warren B. , Robertson Alex F. , Davis Harry C.
Published: September 2009

We examined the relationship of plasma unbound bilirubin concentration and reserve albumin-binding concentration for bilirubin in a sample of 545 neonates. Plasma unbound bilirubin concentration and total bilirubin-binding concentration were determined with the peroxidase assay. Contrary to published reports, we found that plasma unbound bilirubin concentration and plasma reserve albumin for bilirubin-binding concentration are highly correlated (r = ––0.706; p < 0.001) and that the relationship between these two parameters is dependent upon the total bilirubin-binding concentration. That these measured parameters correlate in the same manner as predicted for free bilirubin and free albumin by the law of mass action, suggests that these measurements may be meaningful.
Tracheal Volume Deformation in a Developmental Rabbit Model
Authors: Snyder Steven M. , Shaffer Thomas H. , Bhutani Vinod K.
Published: September 2009

Alterations in tracheal volume were evaluated in a developmental in vivo rabbit model during and following the application of continuous positive pressure (CPP). Sequential volume changes were recorded during 60 min of CPP to a bypassed tracheal segment. The distal trachea was utilized for spontaneous ventilation. CPP of 10 cm H2O was applied to three developmental groups: group I, 5 term newborn pups; group II, 5, 7-day-old pups, and group III, 5 adult female rabbits of 18 ± 6 months old. Changes in tracheal volume were measured by a micropipette system. Following 60 min of CPP, tracheal volumes increased (p < 0.01) by 39.8 % in group I; 36.1 % in group II and 5.1 % in group III. During a recovery period (60 min), return towards initial resting volume was observed in all groups, though maximal persistent volume deformation was observed in groups I and II. Thus, these data indicate tracheal barotrauma in the form of persistent dimensional deformation at early stages of development in an in vivo rabbit model.
β-Adrenergic Receptor Interaction with Guanosine Triphosphate in Fetal Rabbit Myocardial Membranes
Authors: Hatjis Christos G.
Published: September 2009

To investigate whether, in developing fetal rabbit myocardium, the affinity of β-adrenoreceptors (β-AR) for β-AR agonists is regulated by guanosine triphosphate (GTP), we performed in vitro competition experiments utilizing 125I-hydroxybenzylpindolol (I-HYP), a β-AR antagonist, as the radioligand, and l-isoproterenol (l-I) and l-propranolol (l-P), as β-AR agonist and antagonist, respectively. At gestational ages from 21 to 31 days (term 31 days), in the presence of GTP, there was a 4-fold increase in the KI for the inhibition of specific I-HYP binding by l-I but not by l-P. Moreover, in the presence of GTP, there was a significant shift of the Hill coefficient to values closer to 1 only in the case of l-I. We conclude that: (1) β-AR can form a ‘high affinity’ complex with l-I in the absence of GTP, detectable from days 21 to 31 of gestation; (2) the conversion of the former to a ‘low affinity’ state appears to be a GTP-dependent process.
Vitamin A and Biochemical Development. II. Effect of Postnatal Excess Vitamin-A Administration on the Activity of Pyridine Nucleotide-Linked Dehydrogenases
Authors: Shukla R.R. , Joshi Harish C. , Srivastava N. , Misra U.K.
Published: September 2009

The effect of excess vitamin A, (1,000 IU) administration to rat pups on the 4th, 6th, 8th and 10th days of age was studied on the activities of combined HMP dehydrogenases, malic enzyme and isocitrate dehydrogenase on the 11th, 17th and 23rd days of age. The developmental pattern and the effect of vitamin-A administration differs from enzyme to enzyme and organ to organ.
Effects of Different Ways of Covering the Eyes on Behavior of Jaundiced Infants Treated with Phototherapy
Authors: Paludetto Roberto , Mansi Giuseppina , Rinaldi Patrizia , Saporito Maurizio , De Curtis Mario , Ciccimaπa Filippo
Published: September 2009

This study was performed to determine whether covering the eyes with an opaque screen over the head end of the bassinet instead of the normal patch would improve the behavioral organization of jaundiced, but otherwise healthy, term infants treated with phototherapy. 38 matched infants were randomly assigned to have a patch or a screen. Serum biliru-bin at the time of observation was 11.2–17.5 mg/l00 ml (x = 13.7, patch) and 9.4–16.4 mg/100 ml (x = 13.4, screen). 19 infants, of whom 11 were jaundiced (6.2–14.3 mg/l00 ml, x = 10.3), served as control subjects. The infants were examined with the Brazelton scale on the 3rd day after birth, when the patch subjects had been under blue light from 6 to 45 h (x = 23.9), and the screen subjects from 6 to 61.5 h (x = 22.6). The control subjects scored better (all differences, p < 0.05) than the patch subjects on inanimate visual, animate visual, visual and auditory, alertness. The control subjects also did better than the screen subjects on inanimate visual, animate visual, animate auditory, visual and auditory, alertness, but poorer on motor maturity and consolability. The screen subjects did poorer than the patch subjects only on skin color lability. At 1 month of age, 9 sets of matched infants were examined. The only difference was that the control subjects did better than the patch subjects on animate visual and lability of state. Our data confirm the poorer short-term orientation performance of jaundiced infants treated with phototherapy but do not indicate that covering the eyes with an opaque screen improves behavioral organization.
Protein Conservation by the Immature Intestine
Authors: Sivan Yakov , Dinari Gabriel , Wielunski Eliahu , Marcus Hedva , Rosenbach Yoram , Zahavi Ilan , Nitzan Menachem
Published: September 2009

Uptake of intact macromolecules by the immature gut is a well-known phenomenon, but no information exists on the possibility that there is also increased protein loss in the intestinal lumen in preterm infants. We determined alpha-1-antitrypsin (A-1-AT) levels in fecal samples from 39 infants born after 27–41 weeks of gestation from birth up to 30 days of age. A-1-AT levels were elevated only in meconial stools, and low in nonmeconial stools, regardless of associated respiratory disorders, drug administration, and type of nutrition. This study shows that the immature gut has a mature pattern of protein conservation at least as early as after 29 weeks of gestation.
Influence of Environmental Temperature on Glucose Tolerance and Insulin Response in the New-Born Piglet
Authors: Close W.H. , Le Dividich J. , Duée P.H.
Published: September 2009

Plasma glucose and insulin concentrations were measured in 45 new-born piglets both before and at regular intervals throughout a 2-hour period following an intravenous administration of glucose (1 g/kg body weight), at environmental temperatures of 17, 24 and 33 °C. As anticipated, rectal temperature (TR was dependent upon the environmental temperature. During the glucose tolerance test (GTT), TR remained constant at both 24 and 33 °C, 37.0 ± 0.2 compared with 38.0 ± 0.1 °C. However at 17 °C, 12 piglets were able to maintain a constant TR (35.8 ± 0.2 °C), whereas the remaining 6 piglets became hypothermic (32.8 ± 0.4 °C), with TR decreasing continuously throughout the GTT. Their body weight was 210 g below that of the other piglets (p < 0.05). Those piglets at 17 and 24 °C which maintained homeothermy had a higher glucose disappearance rate (KG; 2.00 and 2.31%/min, respectively) than those kept within thermal neutrality (1.66%/min). The insulin response to glucose was similar. During hypothermia, on the other hand, both KG (0.76 ± 0.12%/min) and the insulin response were significantly less (p < 0.05) than in all other piglets. These results indicate that the glucose uptake by the skeletal muscle is increased in cold-exposed, normothermic piglets and results in an increased metabolic rate. Failure to maintain homeothermy diminishes glucose uptake and inhibits insulin release.
Effect of Ritodrine on the Maternal and Fetal Endocrine Pancreas of the Rat
Authors: Aerts L. , Van Assche F.A.
Published: September 2009

Pregnant Wistar rats received four high-dose intramuscular injections of ritodrine per day during the last 6 days of pregnancy. The injections provoked an immediate but transient increase in plasma insulin level, without affecting the plasma glucose concentration. At the end of the treatment, the morphology of the endocrine pancreas and the ultrastructure of the B cells of the ritodrine-treated mothers were similar to those of the control mothers. No lasting influence of the treatment was seen in the fetuses of these rats: body weights, blood glucose and insulin levels, morphology of the endocrine pancreas and ultrastructure of the B cells were all normal.
Prenatal Alcohol Exposure: Abnormalities in Placental Growth and Fetal Amino Acid Uptake in the Rat
Authors: Gordon B.H.J. , Streeter M.L. , Rosso P. , Winick M.
Published: September 2009

On day 20 of gestation, after ethanol feeding (27% ethanol calories, 25% protein), placental weights, DNA, RNA and water content were greater than in controls pair-fed an isocaloric diet without ethanol or those ad lib fed a pellet diet of similar composition. Rat litter size and fetal body, liver and brain weights were similar in all groups. In vivo fetal amino acid accumulation was significantly lower after alcohol exposure despite similar placental uptake. These results indicate that both placental hyperplasia and abnormal fetal amino acid uptake occur at a low alcohol dose when fetal body weight is unaffected.
Relationship between Metabolic Rate and Body Size in Fetal Life
Authors: Bell Alan W. , Battaglia Frederick C. , Makowski Edgar L. , Meschia Giacomo
Published: September 2009

To define the O2 consumption rate (VO2) versus body mass relation during fetal growth, we compared fetal sheep VO2 at mid and late gestation. VO2 per kg wet weight was 37% higher at mid gestation. However, VO2 per kg dry weight was 2.5 times higher, and associated with a high viscera/body weight ratio. Fetal VO2 tends to grow proportionally to body mass because marked decreases in the relative growth of visceral organs and in the VO2/dry weight ratio are accompanied by a decrease in body water.