bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth Hormone-Releasing Hormone
Authors: Argente Jesus , Acquafredda Angelo , Cavallo Luciano , Donnadieu Marcel , Evain-Brion Danièle
Published: September 2009

Plasma growth hormone-releasing hormone (GHRH) was measured by radioimmunoassay in the cord blood from 32 healthy human newborns after 38–41 weeks of gestation. All were born by uncomplicated vaginal delivery. The GHRH levels in cord blood were 78.33 ± 8.35 pg/ml at 40 weeks of gestation, approximately threefold higher than the levels at 38 weeks of gestation (27.00 ± 2.55 pg/ml). No significant differences were found between girls and boys. The rise of plasma GHRH levels in cord blood of the full-term newborns between 38 and 40 weeks of gestation suggests a role of this peptide in the neonatal growth regulation.
Acidemia Potentiates the Plasma Catecholamine Response to Hypoxemia in Fetal Sheep
Authors: Lewis Alan B. , Sadeghi Mahvash
Published: September 2009

Though hypoxemia has been shown to stimulate adrenal medullary catecholamine (CA) release and raise plasma CA concentrations, the extent to which concomitant acidosis influences the magnitude of this response is unclear. Eleven chronically catheterized late gestation (0.8 term) fetal lambs in utero were investigated during a baseline control period and following the onset of umbilical cord constriction-induced hypoxemia (PO2 = 5–15 Torr). Plasma CA rose in response to hypoxemia in all animals but was potentiated by the development of acidemia. Baseline norepinephrine (NE) = 487 ± 113 pg/cm3 and increased to 1,386 ± 127 pg/cm3 (p < 0.001) in response to hypoxemia. Hypoxemia combined with acidemia promoted an even greater rise in NE to 6,726 ± 1,289 pg/cm3 (p < 0.05). Plasma epinephrine (E) = 99 ± 36 pg/cm3 during baseline observations and increased to 512 ± 81 pg/cm3 (p < 0.001) in response to hypoxemia. However, an additional 9-fold increase (p < 0.05) was noted when hypoxemia was combined with acidemia (E = 4,311 ± 1,449 pg/cm3). Thus, acidosis significantly potentiates the magnitude of the plasma CA response to hypoxemia in the late gestation fetus.
Growth and Differentiation of Transplanted Rat Embryos in Intact, Diabetic and Hypophysectomized Hosts: Comparison with Their Growth in situ
Authors: Liu Liming , Russell Sharon M. , Nicoll Charles S.
Published: September 2009

The objectives of this investigation were to evaluate the suitability of a transplant system for studying the endocrine control of growth and differentiation in rat embryonic/fetal tissues, and to gain information on the development of their hormone dependence. Whole 10-day-old rat embryos were transplanted under the kidney capsule of intact, hypophysectomized (Hx) or diabetic (Db) juvenile syngeneic female hosts, and grown there for 3, 6, 9 or 12 days. The wet weight, DNA and protein content of the transplants and of age-matched in situ embryos/fetuses were measured to assess their growth. The transplants in intact hosts increased more than 300-fold in all parameters during 12 days of incubation. However, this increase was only about 4% of the in situ growth. The severe impairment in growth occurred mainly during the first 3-day period when the transplants grew only 5% as much as the in situ embryos. Between days 13 and 22 of gestational age, the increment in transplant growth was 70% of that occurring in situ. Tissue differentiation of the transplants in intact hosts was essentially normal, although they grew as teratomas. Growth and differentiation of transplants in Db and Hx hosts were delayed or inhibited. This inhibition occurred as early as day 3 after transplantation and was corrected by appropriate hormone replacement therapy of the hosts. We conclude that rat embryos/fetuses develop a dependence on a growth hormone-dependent factor (possibly somatomedin) and/or insulin for growth before day 13 of development. This transplant system will be useful for studying other aspects of the control of growth and differentiation of rat embryos/fetuses between days 10 and 22 of gestation.
Carnitine and the Premature
Authors: Rubaltelli Firmino F. , Orzali Alberto , Rinaldo Piero , Donzelli Filiberto , Carnielli Virgilio
Published: September 2009

After birth, the main energy fuel for the newborn is constituted by fat. Carnitine is necessary for the β-oxidation of long chain fatty acids at the mitochondrial level, and seems also to have a role in the metabolism of the branched-chain amino acids, in ammonia detoxification, and in urea production. Colostrum is particularly rich in carnitine whereas semi-elemental formulae and soy-based formulae contain little or no carnitine. Since the newborn has a low capacity for carnitine biosynthesis, it seems useful to administer L-carnitine to infants on total parenteral nutrition, soy-based or semi-elemental formulae.
Stable Isotope Tracers and the Determination of Fuel Fluxes in Newborn Infants
Authors: Bougnères P.F.
Published: September 2009

After birth, newborns adapt from the in utero situation of a continuous fuel supply to the postnatal situation of feeding and fasting periods. In order to maintain adequate fluxes of energetic substrates to their various organs and tissues, neonates must rapidly activate the release of glucose, free fatty acids and ketone bodies into the blood stream. This review will summarize some of the techniques and results available today regarding the in vivo kinetics of an energetic substrate in early postnatal life: the rate of production of this substrate, the overall rate of its uptake by the tissues, its rate of oxidation and contribution to the total caloric demand, the rate of conversion of a precursor into this substrate.
Vitamins and the Premature
Authors: Orzalesi Marcello
Published: September 2009

Vitamins are organic compounds essential in small amounts for metabolic functions. Since they cannot be synthesized in the body they must be supplied with the diet. While fat-soluble vitamins cross the placenta by single and/or facilitated diffusion the water-soluble vitamins are actively transported with the exception of vitamin C. An adequate supply of fat-soluble vitamins to the fetus seems to be dependent on maternal blood levels during gestation. On the contrary, the transfer of water-soluble vitamins is relatively independent of the levels in maternal blood. Due to their immaturity preterm and low birth weight infants require higher dosages of some vitamins compared to healthy full-term newborns.
Arginine Vasotocin and a Novel Oxytocin-Vasotocin-Like Material in Plasma of Human Newborns
Authors: Ervin Gore , Amico Janet A. , Leake Rosemary D. , Ross Michael G. , Robinson Alan G. , Fisher Delbert A.
Published: September 2009

Plasma of human adults contains an oxytocin, vasotocin-like (OT-VT) immunoreactive material that is estrogen responsive in both males and females and the levels of which are elevated during pregnancy. Although OT-VT is immunoreactive with an antiserum raised against synthetic arginine vasotocin (AVT), the elution profile of OT-VT by high-performance liquid chromatography (HPLC) is distinct from AVT, arginine vasopressin (AVP) or oxytocin (OT). Because the fetus is also exposed to high estrogen levels during pregnancy and AVT has been reported to be present in human fetal pituitaries, cord blood samples from 16 vaginally delivered human newborn infants were examined for evidence of OT-VT and AVT. Analysis of an extracted pool of cord blood plasma by HPLC revealed 4 peaks (I-IV) of AVT-like immunoreactivity. Peaks II and IV coeluted with synthetic AVP and OT, respectively, and were attributable to cross-reaction of the AVT antiserum with these peptides. Peak I was identified as AVT on the basis of its coelution with synthetic AVT. Peak III eluted in a manner identical with OT-VT. These results indicate that human newborn plasma contains at least three neurohypophysial peptides, AVP, OT and AVT. Additionally, newborn plasma contains an AVT-like immunoreactive material that is distinct from AVT, AVP and OT, but is identical with a novel OT-VT material observed in plasma of estrogen-primed adults. The physiological significance of AVT and OT-VT in newborn plasma remains to be determined.
Development of Luminal Protein Digestion in Suckling and Weanling Rats
Authors: Button John R. , Koldovský Otakar
Published: September 2009

Because previous measurements of early postnatal, small intestinal fluid, proteolytic activity in man and animals have been contradictory, we characterized the development of luminal protein digestion using a sensitive assay in which iodinated bovine casein was incubated in vitro at 37°C with luminal fluid flushed from the stomach and small intestine of 12-day-old suckling and 31-day-old weanling rats, followed by measurement of radioactivity in trichloroacetic acid-soluble material. Gastric proteolysis at pH 3.2 in the weanling rat was approximately 50-fold greater than that in the suckling rat. Analysis of stomach fluid acid-soluble casein degradation products of weanling rats by chromatography on G-50 Sephadex in the presence of sodium dodecyl sulfate revealed three peaks of radioactivity comprising 65, 18 and 12% of the total product in order of elution. In the jejunum at neutral pH, the proteolytic capacity of the weanling rat was approximately five times that of the suckling rat; such differences were more pronounced in the ileum, however, in which protein hydrolysis of weanling rats was 30-fold higher than that in the suckling rat. In the suckling rat, small intestine proteolytic activity was greater in the jejunum than in the ileum, but in the weanling rat greater protein hydrolysis was present in the ileum. Gel filtration analysis of reaction products in both intestinal segments and at both ages demonstrated two peaks, which constituted 60–70 and 15–23% of the acid-soluble material in order of elution. These studies demonstrate that luminal proteolysis increases in stomach and small intestine during postnatal development in the rat; moreover, segmental differences in proteolytic activity exist. Presumably, these findings reflect the balance between proteases and protease inhibitors from pancreatic secretions, desquamated intestinal epithelial cells, and diet.
In vivo Effects of Glucocorticoid Excess on the Contents of the Rat Fetal Liver in Erythroid Progenitors
Authors: Billat Claudine , Mayeux Patrick , Felix Jean-Marc , Jacquot Robert
Published: September 2009

Following a laparotomy of the pregnant rat at 12 days of gestation, erythroid cell suspensions prepared from the fetal livers at 14 days contained an increased proportion of progenitor cells forming colonies after 2 or 7 days of culture. When laparotomy was performed at 14 days and the fetal livers were sampled at 16 days, the opposite effects were observed. Injection of 0.25 mg/kg dexamethasone to the 12 days pregnant rat increased the proportion of erythroid progenitors in suspensions from 14 days fetal livers; injection of 10 mg/kg (a long-acting dose) produced the opposite effects. Both the composition of the erythroid cell line and its environment change between 12 and 14 days, and these modifications might explain the inversion of glucocorticoid effects between these two stages.
Age-Related Changes in the Kinetics of Iron Absorption across the Guinea Pig Proximal Intestine in vivo
Authors: Srai Surjit K.S. , Debnam Edward S. , Boss Margot , Epstein Owen
Published: September 2009

In the healthy human adult, body iron content is regulated by intestinal iron absorption. However in neonates who are iron replete, iron absorption is inappropriately increased. In this study we have compared the kinetics of iron absorption in the proximal small intestine of the newborn and adult guinea pig in order to gain insight into the cellular mechanisms underlying this difference. Iron uptake was studied in vivo over the concentration range 20–2,000 μM. Total iron uptake could be resolved into saturable and linear components. The kinetic constants for the saturable component in the adult were similar to the neonate. In contrast, the rate of uptake via the linear pathway was 4 times greater in the neonate compared to the adult. It is concluded that the increased absorption of iron by the neonatal guinea pig is due to an enhanced uptake via the linear pathway. In contrast to total iron uptake, we were unable to detect developmental changes in iron transfer into the carcass.
Measurement of Fetal Responses to Vibroacoustic Stimuli
Authors: Leader L.R. , Stevens A.D. , Lumbers Eugenie R.
Published: September 2009

Electrocortical (ECoG) and integrated electromyographic (EMG) activity was recorded in 6 chronically prepared fetal sheep (132–145 days). Recordings were made in fetuses prior to and during repeated vibroacoustic stimulation. In the undisturbed fetus, two patterns of ECoG activity were apparent; high (HV) and low voltage (LV). The fetus responded to this broad spectrum stimulus during both LV and HV ECoG activity. In 18 of the 20 experiments, repeated stimulation was not associated with a change in the background ECoG activity. All fetuses responded at least once to the stimulus. Habituation of the EMG response was observed during both HV and LV ECoG activity. The rate of habituation was independent of the background ECoG activity and was unchanged when experiments were repeated at intervals of more than 3 days. These results show that fetal sheep also respond to vibroacoustic stimulation and with repetition habituation occurs.
Induction of Neural Tube Defects and Skeletal Malformations in Mice following Brief Hyperthermia in utero
Authors: Shiota Kohei
Published: September 2009

Hyperthermia was induced in ICR mice on day 8.5 of gestation by immersing them in hot water. Control mice were immersed in water at 38°C for 15 min. In dams exposed to 42°C for 12.5–15 min or to 43°C for 7.5–10 min, externally malformed fetuses increased significantly and in a dose-related manner. Anterior neural tube defects (exencephaly, anencephaly, encephalocele, and cranial neural tube defect with facial cleft) were induced most frequently. Embryonic and fetal death and skeletal malformations also increased following heat stress. At intervals after heat exposure, sections of embryonic prosencephalon were prepared for light microscopy. At 2 h after heat stress, mitotic figures disappeared almost completely in embryonic tissues. Mitotic activity was inhibited for at least 3 h. At 6 h, there was a burst of new mitotic activity. Some damaged cells became pyknotic and abnormal cells were encountered in the neuroepithelial tissue after 3–12 h. Thus, neural tube defects in mouse embryos following maternal hyperthermia may result from a temporary cessation of cell proliferation and partial necrosis of the embryonic neuroepithelium.
Ovine Fetal Urine Contribution to Amniotic and Allantoic Compartments
Authors: Ross Michael G. , Ervin Gore , Rappaport Valerie J. , Youssef Atef , Leake Rosemary D. , Fisher Delbert A.
Published: September 2009

The ovine pregnancy has been extensively studied as a model for amniotic fluid metabolism potentially serving as a model for human oligohydramnios. However, it is recognized that the ovine pregnancy contains an allantoic fluid compartment not present in human pregnancies at term. Earlier studies in sheep suggested that the fetal urine contribution to allantoic fluid diminished at term, but without an explanation for maintenance of the significant volume of the allantoic cavity. In the present study we examined the relative fetal urine excretion of 3H-inulin into the allantoic and amniotic cavities in the near-term ovine pregnancy. Amniotic and allantoic volumes, as determined by technetium-labelled dextran and chromium-tagged erythrocyte dilution, were similar although there were significant differences in composition. The allantoic fluid compartment received an equal or greater proportion of fetal urine than did the amniotic fluid during the study period. These results indicate the importance of the allantoic fluid volume and composition in the study of ovine fluid dynamics.
Effects of Maternal Hypocaloric Diet Feeding on Neonatal Rat Brown Adipose Tissue
Authors: Felipe A. , Villarroya F. , Mampel T.
Published: September 2009

Hypocaloric diet (control diet diluted 1:1 with cellulose) feeding during pregnancy caused a reduction in the body weight of rat pups at birth whereas the main parameters of brown adipose tissue composition and thermogenic activity were unaffected. When prenatally underfed rat pups were nursed by untreated dams eating control diet during lactation, early (day 4 of life) and late (day 13 of life) neonatal body weight was rehabilitated and brown adipose tissue remained essentially unchanged. When prenatally underfed rat pups were nursed by dams that were fed with the hypocaloric diet during lactation, neonatal body weight continued lower at the two mentioned days of life and the overall thermogenic capacity of brown fat (GDP binding/g body weight) was substantially depressed. The reduction of the brown fat thermogenic capacity in these pups is mainly due to a hypotrophy of the mitochondrial component of the tissue as indicated by the lowered cytochrome oxidase activity. Results indicate that mild maternal underfeeding during lactation may depress brown adipose tissue thermogenic function in neonates whereas similar hypocaloric intakes during pregnancy did not alter brown fat thermogenic capacity.
Circulating Catecholamines and Glucagon in Infants of Strictly Controlled Diabetic Mothers
Authors: Artal Raul , Doug Nam , Wu Paul , Sperling Mark A.
Published: September 2009

Previous studies have demonstrated impaired perinatal adaptation of glucose homeostasis with inappropriately low levels of catecholamines and glucagon in newborn infants born to diabetic mothers. To investigate whether these neonatal changes are related to maternal metabolic control, we sequentially measured plasma glucose, catecholamines and glucagon in the neonatal period in 10 infants born to well-controlled mothers with class B diabetes mellitus after uncomplicated pregnancies. Good glycemic control in the mothers resulted in appropriate counterregulatory hormone responses in the neonatal period, similar to those described in infants born to normal mothers. The significant rise in plasma epinephrine and glucagon paralleled the establishment of euglycemia, further suggesting that these hormones are important for perinatal adaptation of glucose homeostasis.
Decreased Serum Alpha-Amylase Levels in Infected Nigerian Newborn Infants
Authors: Okolo A.A. , Okorodudu A. , Glew R.H. , Omene J.A.
Published: September 2009

Serum alpha-amylase activity was determined in 41 newborn infants with proven bacterial infections and compared to values obtained in 18 healthy control neonates. In the infected neonates serum alpha-amylase value, as determined by the blue starch method, was only 40% that of healthy controls; the mean value of 175.1 ± 64.9 IU/1 for healthy neonates was significantly higher (p < 0.0010) than the value of 82.8 ± 44.4 IU/1 for the infected neonates. Alpha-amylase levels did not correlate with severity of infections or mortality. The sensitivity and specificity of serum alpha-amylase level of 100 IU/1 were 75.6 and 94.7%; the positive and negative predictive values were 91.2 and 84.4%, respectively.
Relationship between Maternal Parity, Basal Prolactin Levels and Neonatal Breast Milk Intake
Authors: Zuppa Antonio Alberto , Tornesello Assunta , Papacci Patrizia , Tortorolo Giuseppe , Segni Giuseppe , Lafuenti Gianni , Moneta Ernesto , Diodato Annunziata , Sorcini Mirella , Carta Salvatore
Published: September 2009

Basal serum levels of prolactin (PRL) in 21 nursing mothers were measured by radioimmunoassay on the 2nd, 3rd and 4th days of the puerperium. The quantity of breast milk suckled during the 4th day of life was also evaluated by calculating the difference in the baby’s weight before and after each feeding. During the first postpartum days, mean basal levels of PRL did not change. However these levels were noted to be significantly lower in the multiparas (p < 0.05) than in the primiparas. In addition, the milk intake in neonates of multiparous mothers was significantly greater (p < 0.05) than that in neonates of primiparous mothers. The authors’ hypothesis, based on the results of animal experimentation described in the literature, is that initiation of breast-feeding is facilitated in multiparas by the increased number of occupied PRL receptors in the mammary glands reflected by the lowered serum levels of the hormone.
Renal Aspects of Calcium and Phosphorus Metabolism in Preterm Infants
Authors: Senterre Jacques , Salle Bernard
Published: September 2009

The aim of this study is to emphasize renal aspects of calcium and phosphorus metabolism from our data of more than 200 metabolic balance studies carried out in preterm infants. Renal production of 125-dihydroxyvitamin D increased rapidly after birth provided the concentration of the substrate, 25-hydroxyvitamin D, is adequate. The gut of preterm infants is able to respond to the active metabolite of vitamin D. Mean plasma phosphate threshold for tubular reabsorption of phosphate is high, about 2.1 mmol/l or 6.5 mg/dl. The low fractional excretion of phosphate cannot be explained by immature parathyroid function nor by renal unresponsiveness to parathormone, at least after the first days of life. It is probably due to regulating factors related to the high rate of growth. Because of reduced glomerular filtration rate, a too high phosphorus intake may result in hyperphosphatemia. Conversely, a too low phosphorus intake will lead to a phosphate depletion syndrome characterized by marked increase in urinary calcium excretion, no urinary phosphate, and hypophosphatemia. Preterm infants with chronic metabolic acidosis are able to acidify urine so that titratable acid is directly related to urinary excretion of phosphate. Clinical implications are that calcium:phosphorus ratio in milk must be adapted according to net bone and soft tissue retention.
Functional Renal Insufficiency: Role of Adenosine
Authors: Gouyon J.-B. , Guignard J.-P.
Published: September 2009

Adenosine, a direct degradative product of 5′ AMP, could be a physiological regulator of glomerular filtration rate and renal blood flow, acting on the renal arteriolar tone and the tubuloglomerular feedback mechanism. Recent experimental evidence strongly suggests an important role for intrarenal adenosine in the hemodynamic renal changes observed in postocclusive acute renal failure, in hypoxemia-induced renal insufficiency, as well as in various experimental models of acute renal failure. In these conditions, adenosine appears to induce predominant postglomerular vasodilatation, as well as preglomerular vasoconstriction when the renin-angiotensin system is activated. Theophylline, a xanthine with strong adenosine antagonistic properties, prevents the hypoxemia-induced renal changes, while enprofylline, a xanthine devoid of such properties, does not prevent these changes. Available data favor the hypothesis that intrarenal adenosine is involved in the pathophysiology of the renal changes observed in the early phase of vasomotor nephropathy.
The Doppler Flow Velocity Waveform in the Fetal Internal Carotid Artery with Respect to Fetal Behavioural States
Authors: van den Wijngaard J.A.G.W. , van Eyck J. , Noordam M.J. , Wladimiroff J.W. , van Strik R.
Published: September 2009

Doppler flow velocity waveforms in the fetal internal carotid artery were recorded in 21 normal pregnancies during fetal behavioural state IF (quiet sleep) and 2F (active sleep) according to Nijhuis and co-workers, from the 36th week of gestation onwards. The present study confirms the earlier finding of a significant reduction of the pulsatility index (PI) in state 2F as compared to state IF at 37–38 weeks of gestation and demonstrates that this difference in PI exists throughout the entire period, in which fetal behavioural states have been described. Furthermore, it is demonstrated that there is a significant reduction in PI of this vessel during the last 4 weeks of gestation, suggesting a haemodynamic redistribution, favouring blood supply to the brain during the latter weeks of gestation.
Effect of Nimodipine on Newborn Lamb Cerebral Blood Flow
Authors: Mogilner Mario , Ashwal Stephen , Dale P. Steven , Longo Lawrence D.
Published: September 2009

The effects of nimodipine, on total and regional cerebral blood flow and cardiovascular function of the newborn chloralose-anesthetized lamb were investigated following intravenous bolus infusions (0.2, 0.6 and 2.0 µg/kg). At 2.0 µg/kg, the mean arterial blood pressure increased from 72.3 to 85.8 mm Hg. Total cerebral blood flow 45 min after infusion increased by 93%, as did regional flows to the gray (101%) and white (77%) matter and subcortex (108%). In a separate series of experiments we decreased arterial blood pressure from 71 to 40 mm Hg by phlebotomy. Nimodipine (30 µg/kg) bolus infusion significantly increased blood flow above control values to the total brain (41%), gray matter (53%), sub-cortex (76%) and brainstem (69%) 10 and 40 min later. However, no further increase in flow or decrease in cerebrovascular resistance was observed when compared to hypotension alone. Nimodipine appears to be well tolerated in the newborn lamb, and appears to increase cerebral flow during normotension. At the levels of hypotension used in the current experiments, nimodipine produced no further increases in cerebral blood flow.
Intestinal Absorption of Calcium in Newborn Piglets
Authors: Lachenmaier-Currle U. , Harmeyer J.
Published: September 2009

The role of vitamin D for intestinal absorption of Ca was studied in neonatal piglets. Piglets of normal phenotype (heterozygotes) and piglets which suffered from pseudo-vitamin D deficiency rickets, type I, which were devoid of renal 25-cholecalciferol-1-hydroxylase were used for the experiments. Intestinal absorption of Ca was measured after an oral dose of 3–7 MBq 45CaCl2· Intestinal absorption of Ca was the same in heterozygotes and homozygotic rachitic piglets during the first 3–4 weeks of life. Ca absorption began to decline in rachitic piglets at the age of 4 weeks. In 8-week-old rachitic piglets intestinal Ca absorption was 50% of control piglets. Body weights of heterozygotes and rachitic piglets were the same at birth and no different weight gains were seen between the two groups during the first 4–5 weeks of life. No differences were observed during the first weeks of life in the concentrations of plasma Ca, inorganic-phosphate and alkaline-phosphatase activity between the groups. Hypocalcemia and hypophosphatemia developed in rachitic piglets between the 3rd and 5th weeks of life. Concentrations of 1,25-(OH)2D3 in plasma declined in heterozygote piglets from 130 ± 26 to 88 ± 19 pg/ml and in rachitic piglets from 67 ± 37 to 23 ± 11 pg/ml during the first 6 weeks. An intestinal nuclear 1,25-(OH)2D3 receptor was absent in neonatal piglets of both experimental groups. It is concluded that intestinal absorption of Ca in piglets during the first 2–4 weeks of life is independent of vitamin D.
Changes in the cAMP Synthesis by Fetal Thyroid during the 5 Last Days of the Intrauterine Life in the Rat
Authors: Pic Pierre , Bouquin Jean-Pierre , El Atiq Fatima
Published: September 2009

The cAMP synthesis by fetal rat thyroids is stimulated in vitro by thyrotropin (TSH) or forskolin during the 5 last days of intrauterine life. The effects are TSH- or forskolin-dose-dependent with equal responses to 20 mlU·ml––1 TSH or to 1 μM forskolin. The magnitude of the responses to TSH or to forskolin decreases significantly as the fetus is ageing. Since forskolin effects bypass hormone receptors, the adenylate cyclase activity can be concluded to decrease during the end of gestation probably in relation with thyroid iodine accumulation. The responses to TSH and forskolin becoming synergic between 19½ and 21½ days indicate modifications of adenylate cyclase properties probably related to some maturation of the enzyme.
Pyruvate Carboxylase, Phosphate-Dependent Glutaminase and Glutamate Dehydrogenase in the Developing Rat Small Intestinal Mucosa
Authors: Hahn P. , Taller M. , Chan H.
Published: September 2009

The activities of glutaminase and glutamate dehydrogenase in the small intestinal mucosa of infant rats were found to increase at the time of weaning. Pyruvate carboxylase activity, on the other hand, was very high during the suckling period and decreased to negligible values at weaning. It is suggested that gluconeogenesis in the infant mucosa occurs primarily via oxaloacetate and not via α-ketoglutarate.
Development of Intestinal Carnitine Transport in Rats
Authors: Leichter Joseph , Hahn Peter
Published: September 2009

The intestinal transport of carnitine in suckling rats (12 and 16 days old) and weaned rats (28 and 75 days old) was studied in vitro using everted small intestinal sacs. The sacs were incubated in a mucosal medium without carnitine or with added carnitine at a 200-μM concentration. The release of endogenous carnitine and its esters into the serosal medium was greatest in the 12-day-old pups and lowest in the postweaning period. In contrast, the transport of carnitine from the mucosal to the serosal compartment was lowest in the 12-day-old pups and higher in the older groups. The present study suggests that the transfer of carnitine from the mucosal to the serosal compartment is influenced by the presence of endogenous carnitine in the intestinal mucosa, which in turn is determined by the age of the animals.
Brain Development in the Fetus, Neonate and Infant
Authors: Herschkowitz N.
Published: September 2009

In structural brain development eight interrelated but distinguishable events can be recognized: (1) neuronal induction, (2) neuroblast proliferation, (3) neuronal migration, (4) neuronal selective aggregation, (5) neuronal differentiation and formation of specific patterns of connection, (6) neuronal death, (7) selective synapse elimination and (8) myelination. The basic mechanisms regulating these developmental events are genetically determined but at any stage of development epigenetic and environmental factors modulate the genetic regulation. This paper reviews representative samples of work in animal experiments and knowledge in human fetal brain development by several authors.
Vitamin D Deficiency, Pancreatic and Small Intestinal Enzyme Development in Rats
Authors: Jirapinyo Pipop , Srimaruta Nualanong , Lebenthal Emanuel , Lee Ping-Cheung
Published: September 2009

Maternal vitamin D deficiency has been shown to lead to reduced body weights in developing rat pups. To evaluate the effects of vitamin D deficiency alone both in dams and pups during the perinatal age on the ontogeny of gastrointestinal enzymes, female weanling rats (3 weeks of age) were divided into three groups. Groups I and III were fed a control (vitamin-D-replete) diet. Group II were fed a vitamin-D-deficient diet. Six weeks afterward they were mated with normal male rats while continuing on their respective diets until sacrifice. Only rats that delivered their pups on the same day from each group were brought into the study. Litter sizes of groups I and II were adjusted to 10, while group III was adjusted to 13 such that the rate of growth paralleled that of group II. At 19 days after birth, all dams and pups were sacrificed. There were no differences in the calcium and phosphorus contents in breast milk obtained from dams of each group. The serum calcium concentration of pups from group II (vitamin-D-deficient) was lower than the other groups. Body weights of pups from groups II and III were significantly lower than those of group I. The mucosal weight, total mucosal protein, mucosal DNA, sucrase, and maltase activities from groups II and III were similar, but lower than group I. Pancreatic weight, total pancreatic protein, DNA, amylase, and lipase activities from groups II and III were also similar, but lower than group I. Vitamin D deficiency was confirmed in both dams and pups from group II. This deficiency during gestation and lactation apparently affected the development of gastrointestinal enzymes. The effect was, however, similar to that due to an increase in litter size (group III). The results suggest that vitamin D deficiency in dams probably caused lower milk volume which resulted in a partial dietary restriction to the pups, thus affecting the development of their pancreatic and mucosal enzymes. The effect of vitamin D deficiency is, therefore, secondary.
Effect of Bupivacaine Hydrochloride on Bilirubin Production in Neonatal Rats
Authors: Gale Rena , Vreman Hendrik J. , Ferguson II James E. , Stevenson David K.
Published: September 2009

The rate of bilirubin production was studied in 12-hour-old rats exposed to bupivacaine HCl by subcutaneous injection. The bilirubin production was estimated by measuring the excretion rate of carbon monoxide (VeCO) using an open flow-through system. No significant difference was found between the VeCO of bupivacaine HCl-treated and control animals, or between the levels of bilirubin in the pooled blood of treated (0.92 ± 0.32 SE mg/dl) and control (1.0 ± 0.28 SE mg/dl) animals. These negative findings support the clinical studies which have not demonstrated an association between epidural anesthesia with bupivacaine HCl and neonatal jaundice.
In vivo and in vitro Effects of Theophylline on the Peripheral Blood Mononuclear Cells from Preterm Infants
Authors: Bessler Hanna , Sirota Lea , Gilgal Ritta , Dulitzky Frederika , Djaldetti M.
Published: September 2009

The in vivo effect of aminophylline (theophylline ethylenediamine) on cAMP levels and the mitogenic response of peripheral blood mononuclear cells (PBMC) from preterm infants were investigated. Increased cAMP levels and reduced response of these cells to concanavalin A (Con A) were found in preterm newborns who received intravenous aminophylline. No inhibitory effect of the drug on phytohemagglutinin (PHA)-induced proliferation was observed. cAMP levels of PBMC derived from preterm infants were significantly lower than those of term newborns. The in vitro effect of theophylline on the mitogenic response of PBMC from adults, term and preterm infants was also compared. It was found that PBMC from adults were significantly more sensitive to the inhibitory effect of theophylline on Con A-induced proliferation than were PBMC from either term or preterm infants, whereas the effect of the drug on the mitogenic response to PHA was similar in the three groups. These data suggest differences either in the sensitivity to increased cAMP concentration between PBMC from adults and newborns or in their lymphocyte subpopulations.
Homeothermal Adjustment in the Immediate Postdelivered Infant Monitored by Continuous and Simultaneous Measurement of Core and Peripheral Body Temperatures
Authors: Kubota Shiro , Koyanagi Takashi , Hori Eiichi , Hara Kenji , Shimokawa Hiroshi , Nakano Hitoo
Published: September 2009

To investigate the process of homeothermal acclimation to extrauterine environment, core and peripheral body temperatures in the human neonate were continuously and simultaneously recorded. Twenty-one term-delivered babies were divided into two groups. In group I, 10 babies were kept at 32–34 °C for the first 2 h of extrauterine life and at 24–26 °C for the succeeding 6 h. In group II, 11 were kept at 24–26 °C for the first 8 h after delivery. Three thermisters were used: one catheter-type placed in the rectum and two involving the zero-heat flow method placed at the sternum and footsole. Because of technical limitations, rectal temperature (Tre) was monitored until temperature in the sternum (Tst) stabilized, after which this transition from Tre to Tst was noted as Tre-st. Changes in resulting temperatures were quantitatively analyzed using Student’s t test, for both intra- and intergroup comparisons. Tre-st significantly decreased during the first 28 and 42 min for groups I and II, respectively, after which time this temperature rose and stabilized. In group I, the Tre-st reached the homeothermal stage at 2 h 49 min, while 4 h 27 min were required for group II. In group I, the footsole temperature (Tsf) reached a plateau after 2 h 10 min. In group II, Tsf showed a large decrease followed by a slow rise, with no stability achieved during the 8-hour observation period. Intergroup comparisons revealed that the mean Tsf reached conditions not significantly different from those of group I at 6 h 57 min. From the differences in changes seen in the patterns of body temperature distribution, neonates show different courses of homeothermal acclimation to extrauterine life, depending on the ambient temperature to which they are initially exposed.
Pituitary Changes of Desacetyl-α-Melanocyte-Stimulating Hormone throughout Development
Authors: Facchinetti F. , Storchi A.R. , Furani S. , Radi D. , Genazzani A.R.
Published: September 2009

Adrenocorticotropin (ACTH), α-melanocyte-stimulating hormone (α-MSH) and desacetyl-α-MSH (des-α-MSH) concentrations were evaluated in 4 embryos and 18 fetal pituitaries collected after spontaneous (n = 9) and prostaglandin-induced abortion (n = 9) at 13–25 weeks of gestation. The peptides were measured by radioimmunoassays after a high-performance liquid chromatographic separation of the homogenates. In both embryonic and fetal pituitaries, des-α-MSH concentrations were 2–4 times higher than those of α-MSH and 1- to 50-fold increased in comparison to those of ACTH. Either melanotropin showed the highest pituitary content in the first part of the second trimester, while the ACTH content remained constant. In the oldest fetuses (over 20th week), the pituitaries collected after prostaglandin-induced abortion showed markedly increased values of both des-α-MSH and α-MSH in comparison to samples collected after spontaneous abortion. In conclusion, des-α-MSH, the typical melanotropic hormone of fetal pituitary, undergoes important changes during development. Des-α-MSH seems to be the end product of proopiomelanocortin cleavage and its pituitary content increases in concomitance with the fetal adrenal sprout. Moreover, these data indicate that the intermediate pituitary lobe could be activated by the stress of labor after the 20th week of pregnancy.
Evidence for Functional Immaturity of the Ornithine-Urea Cycle in Very-Low-Birth-Weight Infants
Authors: Boehm G. , Müller D.M. , Beyreiss K. , Räihä N.C.R.
Published: September 2009

In a randomized, prospective study the response of serum urea concentration to different protein intakes was studied in two groups of preterm infants with different gestational ages on the 8th and the 21st day of life. 16 very-low-birth-weight (VLBW) infants (GA: 29–31 weeks) and 17 low-birth-weight (LBW) infants (GA: 31–33 weeks) were fed either with fresh human milk or with fortified human milk. The protein intake varied between 2.1 and 3.3 g/kg/day. On the 8th day of life the VLBW infants did not respond to higher protein intakes by increased serum urea concentrations, although a clear correlation was found between protein intake and serum alpha-amino-nitrogen concentrations in these infants. The more mature LBW infants responded to a high protein intake by increased serum urea concentrations on the 8th day of life. On the 21st day of life protein intake correlated to both serum urea and alpha-amino-nitrogen concentrations in all infants studied. These findings are consistent with a somewhat limited capacity of the immature infant for expansion of urea production for some time after birth. This immaturity should be considered when metabolic responses to protein intake are studied and evaluated in such infants.
Glycogen Metabolism in Late Gestation in Fetuses of Maternal Diabetic Rats
Authors: Margolis Ronald N. , Seminara Daniela
Published: September 2009

Fetal hyperglycemia and hyperinsulinemia, as induced by administration of streptozotocin to pregnant rats, during late gestation resulted in the onset of the major period of hepatic glycogen synthesis and accumulation at days 19–20 of gestation (22 days = term) rather than at days 20–21 as for normal fetuses. In addition, sustained high levels of liver synthase phosphatase and phosphorylase phosphatase activities prevented the normal term increase in activation of phosphorylase and inactivation of synthase in hyperglycemic/hyperinsulinemic fetuses. The suppression of term fetal changes in phosphorylase activation in particular contributed to the maintenance at term of fetal liver in a condition favoring glycogenesis rather than glycogenolysis.
Age-Dependent Effects of β2-Adrenergic-Stimulating Drugs on Fetal Rabbit Lung Liquid and Adrenal Catecholamines
Authors: Lundell K.-H. , Bergman B. , Svensson K. , Hedner T.
Published: September 2009

The effects of the β2-adrenergic-stimulating drug, terbutaline, were studied on fetal rabbit lung liquid (FLL) at gestational ages between 25 and 30 days. At delivery terbutaline reduced FLL in rabbit fetuses with a gestational age of 26–30 days. The most pronounced reduction of FLL was seen at 28 days. Terbutaline administration reduced the wet lung weight/body weight (WLW/BW) ratio at delivery in the 28- and 30-day-old rabbit pups. In the 26-day-old animals, β2-adrenergic stimulation had no significant effect on the WLW/BW ratio and at 25 days of gestational age the ratio was increased. After parturition, however, the difference in WLW/BW between the terbutaline and control animals, seen at birth, was attenuated and, at 60 min of postnatal age, the difference was no longer observed. Terbutaline decreased the adrenal content of noradrenaline and adrenaline most marked at 28 days of gestational age, but did not alter the adrenaline/noradrenaline ratio. Furthermore, adrenal dopamine was decreased after terbutaline, suggesting a decreased catecholamine synthesis. Our data show that a positive effect of terbutaline on FLL in rabbit pups was most marked during late but not early gestational age. β2-Adrenergic treatment may, however, reduce adrenal catecholamines.
Beta Blockers Inhibit Fetal Thromboxane A2 Production in vitro
Authors: Viinikka Lasse , Ylikorkala Olavi
Published: September 2009

The effects of beta-blocking propranolol, metoprolol, atenolol and labetalol on the production of the proaggregatory and vasoconstrictive thromboxane A2 (TxA2) by fetal platelets were studied. To this end, umbilical blood samples were allowed to clot in the absence or presence of various concentrations of these agents, and the release of TxB2 (a metabolite of TxA2) was measured. Propranolol and labetalol inhibited TxA2 production in 0.1-mmol concentrations and metoprolol and atenolol in 1-mmol concentrations. The required concentration was always higher than could be achieved by peroral treatment. Beta blockers may have this effect through phospholipase A2 because the conversion of exogenous arachidonic acid to TxB2 was not affected except in the case of propranolol, which inhibited slightly TxB2 formation from exogenous arachidonic acid.
Copper Metabolism in the Macular Mutant Mouse: An Animal Model of Menkes’s Kinky-Hair Disease
Authors: Shiraishi Noriyuki , Aono K. , Taguchi T.
Published: September 2009

The tissue copper contents were measured in mutant (hemizygous macular male and homozygous macular female), heterozygous macular female and normal mice. The copper content in kidney and small intestine from 7-day-old mutant and heterozygote were extremely high compared to normal mice, whereas the copper content in other tissues (liver, brain, spleen and serum) was low. Copper content in whole body of mutant mice was extremely low at three stages (18 days gestation, 1 day old, and 7 days old) compared to normal mice with the exception of the mutant fetus at 14 days of gestation. Renal copper contents in the mutant fetus at 18 days of gestation and in the 1-day-old mutant were not changed compared to normal mice, whereas that in 7- and 14-day-old mutant mice was significantly elevated. Hepatic copper content of the mutant mice was extremely low at all stages compared to normal mice. Copper therapy was applied to 7-day-old mutant mice. At 1 day after injection, hepatic copper content in the mutants had increased slightly in comparison with the normal control mice, whereas renal copper content was extremely increased. At 7 days after injection, hepatic copper content in the mutants was decreased greatly in comparison with normal control mice, whereas an increase in renal copper content had remained.
Spectral Analysis of Impedance Respirogram in Newborn Infants
Authors: Äärimaa T. , Välimäki I.A. T.
Published: September 2009

Respiratory rate (RR), transthoracic electric impedance (TEZ) and transcutaneous PO2 and PCO2 were monitored during the 5 first postnatal days in 54 neonates on three separate occasions. There was no difference in the overall RR between the term and healthy preterm babies on different days of recordings but RR of the babies with RDS (who were all ventilated) was lower on day 1 (p < 0.01). When the power spectrum of the TEZ respirogram was computed and the spectral density was divided into low-frequency (LF, < 0.20 Hz) and high-frequency (HF, > 0.20 Hz) areas, the LF/HF ratio of healthy preterm babies was greater than that of term babies on day 1 (p < 0.01). The preterm babies with RDS did not differ from the term babies in this respect. The LF/HF ratio was negatively correlated with gestational age and it had a positive correlation to PtcO2 (p < 0.05) and PtcCO2 (p < 0.01) (R2 = 0.07). The result evidences that the control of respiration changes in relation to maturity and the LF/HF ratio is a quantitative indicator of respiratory variability reflecting this development.
Renal Effects of d-Tubocurarine and Pancuronium in the Newborn Rabbit
Authors: Gouyon J.-B. , Torrado A. , Guignard J.-P.
Published: September 2009

The acute renal effects of d-tubocurarine and pancuronium were assessed in 14 anesthetized newborn rabbits. Glomerular filtration rate (GFR) and renal blood flow (RBF) were calculated from the inulin and p-aminohippuric acid clearances, respectively. Each animal acted as its own control. At doses used in human neonates, d-tubocurarine administration (0.80 mg/kg) produced a marked increase in renal vascular resistance (+123 ± 62%) with a concomitant significant decrease in GFR (––35.4 ± 12%) and RBF (––39 ± 13%). Pancuronium administration (0.25 mg/kg) was associated with a nonsignificant decrease in GFR (––19 ± 17%) and RBF (––20 ± 12%) and an increase in renal vascular resistance (+66 ± 52%). These results stress the need for careful monitoring of renal function in neonates receiving nondepolarizing muscle-relaxant agents.
Alterations of Serum High-Density Lipoproteins and Hepatic Lipase Activity in Congenital Hypothyroidism
Authors: Tenenbaum Denis , Gambert Philippe , Fischbach Michel , d’Athis Philippe , Nivelon Jean-Louis , Lallemant Christian
Published: September 2009

Fourteen term newborns and infants with congenital hypothyroidism were studied before (To) and after (T1) 1 month of replacement therapy. From T₀ to T1 serum total cholesterol and high-density-lipoprotein cholesterol remained constant and at normal levels whereas low-density-lipoprotein apolipoprotein B and triacylglycerol concentrations increased slightly. The proportion of large-size high-density-lipoprotein subfraction was high at T₀ and decreased very significantly at T1. Conversely, postheparin serum hepatic lipase activity was low before treatment and increased after thyroxine therapy. Lipoprotein lipase activity remained low throughout the study. These results suggest that, in contrast to adult hypothyroidism, low-density-lipoprotein catabolism is not altered in congenital hypothyroidism. However, as in adults, a defect of lipolytic enzyme activities is present and can induce an impairment of the elimination of cholesterol via the high-density-lipoprotein route and, potentially, of the catabolism of triglyceride-rich lipoproteins. Beyond the scope of congenital hypothyroidism, one should keep in mind these results when attending infants with transient low thyroid hormone levels and lipid intolerance.