bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Maternal Ethanol Ingestion on the Uptake of Alpha-Aminoisobutyric Acid by Fetal Rat Liver, Lung and Brain
Authors: Snyder Ann K. , Singh Sant P. , Pullen Gordon L. , Eman Svetlana
Published: September 2009

Maternal ethanol ingestion reduced the uptake of [14C]-α-aminoisobutyric acid (AIB) by placenta and fetal liver, lung and brain when compared with pair-fed or ad libitum-fed controls. The ratios between fetal tissue and plasma radioactivities indicated reduced AIB transport into the tissues of the ethanol-fed fetuses. Organ weights correlated with the fetal:maternal plasma 14C ratio, an indicator of the rate of placental AIB transfer, and with the tissue AIB uptake. These observations suggest that ethanol-induced growth retardation may reflect reduced nutrient availability resulting from impaired transport processes.
Circadian Blood Pressure Pattern in Full-Term Newborn Infants
Authors: Gemelli M. , Manganaro R. , Mami C. , Rando F. , De Luca F.
Published: September 2009

A fully automatic noninvasive device (Dinamap) was used for monitoring blood pressure (BP) and heart rate repetitively over 48 h in 21 full-term newborn infants (9 males and 12 females), aged 4 days in order to clarify the occurrence of a circadian rhythm (CR). The data collected were analyzed by computer statistical analysis. Mean values and standard error of BP and heart rate measured at hourly intervals in males and females were computed and plotted as chronograms. However, each newborn infant was analyzed for a CR of BP and heart rate by the single cosinor fit of a 24-hour cosine curve. The analysis of the chronograms revealed that the values of systolic and diastolic BP show an hour-by-hour significant fluctuation in male infants, but not in female infants. CR development of BP is present only in a minority of newborn infants and reveals sex and interindividual differences. CR of heart rate is absent in all infants. The physiological significance of these findings was discussed, and the importance of knowing the physiological variances of BP in infants in order to obtain a correct clinical evaluation was stressed.
Effects of Testosterone on Morphology and on Progestin and Estrogen Receptor Levels in the Mouse Uterus and Mammary Gland
Authors: Edery Marc , Mills Karen T. , Bern Howard A.
Published: September 2009

The effects of androgen on the morphology and levels of cytosolic estrogen and progestin receptors (ER and PR) were studied in the mouse uterus and mammary gland. Testosterone neonatally and/or continuously in the adult lowers ER and PR levels particularly at early ages (40–60 days of age) in both the uterus and mammary gland. At older ages, less prominent changes in ER and PR levels are observed. Neonatal androgen treatment appears to exert both direct effects on the uterus and mammary gland and indirect effects (via the hypothalamo-hypophysio-ovarian axis). At all ages, neonatal testosterone in combination with continuous adult testosterone consistently depressed PR levels in both uterus and mammary gland, indicating that testosterone is a negative modulator of PR in these tissues.
Free Cortisol of Human Plasma in the First Three Months of Life
Authors: Rokicki Wladyslaw , Forest Maguelone G. , Loras Bernadette , Bonnet Hubert , Bertrand Jean
Published: September 2009

Total cortisol as well as percentage and absolute free cortisol values were determined in 75 full-term, 88 premature and 38 small-for-age (born at term) infants in the first 3 months of life. Equilibrium dialysis and radioimmunoassay were used to estimate the percentage value of the unbound fraction and the value of total cortisol from which absolute free cortisol level was calculated, respectively. A systematic decrease in the free cortisol value was observed in all the three groups of infants during the study period (in full-term infants from 32.3 to 19%, in prematures from 36.6 to 20.8%, and in small-for-age infants from 32.3 to 19.2%). A comparison between the percentage values of free cortisol in the groups studied revealed only slight differences which were not significant. The absolute free cortisol values in full-term infants were highest immediately after birth (4.05 μg/dl), then they fell to the lowest level of 0.67 μg/dl observed between the third and fifth days of life, and increased afterwards reaching the level of 1.89 μg/dl in the third month. The absolute free cortisol values in premature newborns at 3–5 days of life exceeded the values observed in full-term subjects. The pattern of free cortisol in the prematures seems to be ‘delayed’ as compared with that in full-term newborns. The absolute free cortisol values in small-for-age infants were much more similar to those found in the full-term subjects, than to those in premature babies.
Effect of Colostrum Feeding on Protein Metabolism in the Small Intestine of Newborn Lambs
Authors: Patureau Mirand P. , Mosoni L. , Levieux D. , Attaix D. , Bayle G. , Bonnet Y.
Published: September 2009

In a first experiment with 24 newborn lambs, the promoting effect of colostrum feeding on the fresh weight of the small intestine and its protein content was demonstrated by comparison with that of other dietary treatments (fasting, lactose, protein hydrolysate feeding). In a second experiment, the amounts of colostral IgGl entrapped within the intestine wall and the valine incorporation rates into the intestinal protein were determined in 3-, 8- and 18-hour-old lambs fed either cow milk, cow colostrum or ewe colostrum. The amounts of IgGl in the small intestine wall and the valine incorporation rates were higher in the lambs fed colostrum (ewe or cow) than in the milk-fed animals. The intestinal protein increase resulted primarily from the retention of colostral proteins in the colostrum-fed newborn lambs. However, colostrum feeding stimulated intestinal protein synthesis more actively than milk feeding.
Lipoprotein Lipase Activity in the Liver of Starved Pregnant Rats
Authors: Vilaró Senén , Testar Xavier , Ramirez Ignasi , Llobera Miquel
Published: September 2009

We have previously described the appearance of lipoprotein lipase (LPL)-like activity in the liver of 24-hour-starved 21-day pregnant rat, but it is not known up to what point the appearance of this activity depends on the gestation stage and/or the length of the starvation period. We found that 24 h of starvation resulted in the appearance of LPL-like activity in the liver of 21-day-pregnant but not in 17-day- or nonpregnant rats. This appearance was found only after 24 h but not after 48 or 72 h of starvation. We demonstrate that this activity actually corresponds to LPL, since it is inhibited by either 1.5 M NaCl or 1.5 mg/ml protamine sulfate, is serum-dependent, and could be separated from hepatic lipase activity by using heparin-Sepharose affinity chromatography. The possible relationship between the appearance of LPL activity in the liver and the enhanced metabolic response to starvation in pregnant rats at term is discussed. It is suggested that the presence of this enzyme in the liver would allow the direct uptake by the liver of circulating triacylglycerols.
Metabolic Effects of the Delay in Obliteration of the Umbilical Cord in the Newborn Rat
Authors: Arranz Lorena , Ruiz Miguel A. , Fernandez Emilio , Medina José M.
Published: September 2009

The effect of delay in obliteration of the umbilical cord on the time-courses of liver glycogen, blood glucose and lactate concentrations and blood PO2, PCO2 and pH during the first 6 h of extrauterine life were studied. Obliteration of the umbilical cord 2 h after delivery resulted in an increase in liver glycogenolysis without significantly affecting the other parameters studied. A 6-hour delay in obliteration of the umbilical cord increased lactiacidemia and decreased blood PO2 and pH without significantly affecting the other parameters studied. A supply of pure oxygen to the newborns decreased lactiacidemia and increased PO2, although the differences between obliterated and nonobliterated newborns remained. These results suggest that hypoxia due to the persistence of placental circulation results in an increase in lactiacidemia as a consequence of a decrease in lactate utilization.
Factors That Influence the Distention of Immature Lung with Artificial Surfactant
Authors: Ferrer-Roca O. , Padilla M.C. , Domenech E.
Published: September 2009

The exogenous therapy of respiratory distress syndrome with artificial surfactants is controversial. In the present work we treated premature rabbits with artificial ultrasonic obtained surfactant suspensions [dipalmitoyldiphosphatidylcholine:dipalmitoyldiphosphatidylglycerol (DPPCDPPG) 7:3] in various physical conditions produced by changing the carrier (saline solution and amniotic fluid) or incubating at 41 °C. Nonincubated samples (S0) were nonactive, the best effect on alveolar distention being found after 8 h incubation (S8), while 16 h incubated samples (S16) were less effective. Liposomal size of the mixtures correlated with their effectiveness; small unilamellar liposomes were nonactive, large unilamellar ones were active and in presence of large multilamellar liposomes the tensioactive effect decreased. Fifty-one percent of the alveolar distention, evaluated by morphometry, was due to treatment and 11% was linearly related to body weight. The ponderal effect of body weight was mathematically excluded in order to obtain more uniform results; the resulting parameter was called true treatment influence on alveolar distention (TIAD). 15% of TIAD varied due to the carrier, with significantly better results when saline solution was used as a carrier. These findings question the hypothesis of the prevention of respiratory distress syndrome by means of intraamniotic injection of surfactants.
Cardiorespiratory Patterns in Infants Presenting with Apparent Life-Threatening Episodes
Authors: Southall D.P. , Janczynski R.E. , Alexander J.R. , Taylor V.G. , Stebbens V.A.
Published: September 2009

A total of 305 infants presenting with apparent life-threatening events (ALE) were referred by their paediatricians and underwent 24-hour tape recordings of electrocardiogram and abdominal breathing movements (from a pressure capsule transducer). Seventy-seven of these infants, all full-term (≥ 37 weeks of gestation), were randomly selected, followed up for clinical outcome, and their recordings subjected to a detailed analysis of heart and respiratory rates and breathing patterns. Recordings on 157 age-matched, full-term controls were similarly analysed for comparison purposes. One of the 77 patients suffering from ALE had a pre-existing neurodevelopmental problem, and 4 more cases showed this at follow-up, including 1 case whose ALE was subsequently diagnosed as originating from non-accidental injury. Compared with controls and as a group, the patients suffering from ALE showed higher numbers of apnoeic pauses (p < 0.001), larger quantities of periodic breathing (p < 0.01) and lower respiratory rates during regular breathing (p < 0.01).
Vitamin A Storage in Lungs during Perinatal Development in the Rat
Authors: Shenai Jayant P. , Chytil Frank
Published: September 2009

We examined the ontogeny of vitamin A storage in fetal and neonatal lungs during perinatal development in the rat. High-performance liquid chromatography was used to measure concentrations of vitamin A and its esters, retinyl palmitate and stearate, in various fetal and neonatal tissues at times ranging from gestational day 14 through 21 and from postnatal day 1 through 21. The data show that significant vitamin A storage occurs in the fetal lung during the latter one-third of prenatal life. Depletion of these stores that begins before birth and continues into the early postnatal period suggests that the developing lung may be dependent on these local vitamin A stores during active growth and differentiation. The utilization of vitamin A stores in the developing lung appears to be independent of the liver stores of vitamin A.
Maternal Caffeine Ingestion Increases the Tyrosine Level in Neonatal Rat Cerebrum
Authors: Tanaka Harumi , Nakazawa Kazuharu
Published: September 2009

The cerebral free amino acids in neonatal rats, from dams given 0.04% caffeine in the drinking fluid ad libitum before and/or during pregnancy throughout the lactational period, were examined on days 1, 5 and 10. Significantly reduced cerebral weight was observed on day 1 with a mean caffeine level of 7 μg/g wet weight. The tyrosine concentration in the cerebrum, but not that in the liver, was increased on days 1 and 5 with approximate mean caffeine levels of above 1.5–2.0 μg/g wet weight. The tyrosine level showed a positive correlation with the caffeine level in neonatal cerebrum only on day 1 in the group with caffeine ingestion after pregnancy. There was no significant increase in the fetal cerebral concentration of MOPEG-SO4 on day 5 with maternal caffeine. These results suggest that maternal caffeine disturbs the neonatal cerebrum through tyrosine and tyrosine hydroxylase, and then produces behavioral abnormalities in developing rats.
Metabolism of Intravenous Phenylalanine by Babies Born before 33 Weeks of Gestation
Authors: Walker V. , Mills G.A.
Published: September 2009

Random urine samples collected weekly from 22 infants of 25–32 weeks of gestation were analyzed by capillary gas chromatography-mass spectrometry to define the normal organic acid profile. Increased excretion of phenolic acid derivatives of phenylalanine and tyrosine was found in 21 samples from 13 babies during established parenteral nutrition. Compared with 53 samples collected during milk feeding, phenyllactic acid, 4-hydroxy-3-methoxyphenyllactic acid, and N-acetyltyrosine were excreted significantly more often and 4-hydroxyphenyllactic and 4-hydroxyphenylpyruvic acids at significantly higher concentrations. The mean daily intake of phenylalanine (197 mg/kg) was significantly higher and that of tyrosine (22 mg/kg) significantly lower during parenteral nutrition. Three cyclohexanediol isomers were identified which might have derived from phenylalanine or one of its metabolites.
Correlation of Commonly Used Measures of Intrauterine Growth with Estimated Neonatal Body Fat
Authors: Wolfe Honor M. , Brans Yves W. , Gross Thomas L. , Bhatia Rupinder K. , Sokol Robert J.
Published: September 2009

Several morphometric measures have been used to identify infants at greatest risk from aberrant intrauterine growth. 119 near-term infants were studied to answer the more basic question of how well measures, such as birthweight percentile, ponderal index, the body mass index and the weight/length ratio reflect body fat in the neonate. Skinfold thicknesses were measured as an estimate of fat stores. Multiple regression analysis revealed that the weight/length ratio showed the strongest correlation with relative adiposity, explaining 52% of the variance. Further, sequential exponentiation of the crown-heel length in body mass index and ponderal index decreased the correlation with estimates of body fat. The simple weight/length ratio, exhibiting both a close correlation with body fat and independence of gestational age, race and sex, in near-term infants may be the best morphometric measure of the nutritional component of intrauterine growth in the neonate.
Differences in Sialic Acid Expression of Lung Alveolar Cells between Normal and Intrauterine Growth-Retarded Rat Fetuses
Authors: Konishi Hideki , Ghazizadeh Mohammad , Araki Tsutomu
Published: September 2009

The expression of sialic acid on the luminal surface of lung alveolar epithelial cells was compared in normal developing and intrauterine growth-retarded (IUGR) rat fetuses during the late gestational and early neonatal periods using neuraminidase treatment of the tissues and staining with a galactose-binding lectin from peanut. In IUGR fetal lung tissues, there were more staining for free galactosyl residues (before neuraminidase treatment) and less staining for sialic acid-bound galactosyl residues (after neuraminidase treatment) than in normal fetal lung tissues during the developmental stages. The staining reaction after neuraminidase treatment was mostly confined to the type 2 alveolar cell surfaces especially on microvillous surfaces. These findings suggest that in IUGR rat fetuses galactosyl residues of the lung alveolar epithelial cell surfaces are not sufficiently masked with terminal sialic acids resulting in a disturbance in the normal maturation process of the alveolar epithelial cells.
Influence of an Alpha-1-Adrenoceptor Antagonist, Nicergoline, on Placental Prostanoid Production in Streptozotocin-Induced Diabetic Pregnant Rats
Authors: Chartrel N. , Clabaut M. , Boismare F. , Schrub J.Cl.
Published: September 2009

The aim of this study was to determine if placental prostanoids could mediate the vasodilating action of an alpha- 1-adrenoceptor antagonist, nicergoline (400 μg/kg i.p.), during late pregnancy in streptozotocin-induced diabetic rats (40 mg/kg i.v.). Placental prostanoid concentrations were evaluated by radioimmunoassay. Prostaglandin E2 levels showed a highly significant increase in diabetic and nondiabetic rats treated with nicergoline (p < 0.001). 6-Keto-PGF1α concentrations were slightly increased in diabetic rats compared to controls, and this increase was reversed by both nicergoline and insulin treatments. In all groups studied thromboxane B2 levels were comparable. It is concluded that prostaglandin E2 could mediate the vasodilating action of nicergoline on the placental irrigation and, therefore, improved the hemodynamic state of this organ in diabetic rats.
Carbon Monoxide Production by Nonbacterial Sources after Heme Feeding of Neonatal Rats
Authors: Stevenson David K. , Hamori Charles J. , Carlton Rachel R. , Castillo Ricardo O. , Kerner Jr. John A. , Vreman Hendrik J.
Published: September 2009

We determined the relative potential for nonbacterial CO production after oral heme feeding of 12-hour-old rats. The intestinal flora was eliminated by treatment with kanamycin, ampicillin, and neomycin. CO excretion (VeCO) was measured after oral administration of heme (0.64 µmol/animal). Antibiotic treatment alone did not significantly affect the VeCO of rats gavaged with saline. Heme administration increased (p < 0.05) the VeCO during t = 1–11 h with a peak at 3 h. Antibiotic treatment reduced this VeCO (p < 0.05) during t = 2–8 h, but its level (peak at t = 2–3 h) was still significantly (p < 0.05) above its nonheme control. The results confirm that bacterial degradation of heme is an important source of CO in suckling rats not pretreated with broad-spectrum antibiotics. However, oral heme feeding of gut-sterilized animals yielded transiently significantly increased VeCO. HO-mediated degradation of enteral heme is a likely nonbacterial source of CO and possibly bilirubin in the neonate.
Morphometrical Studies on Perinatal Development of Glomerular Components in Rat
Authors: Okada Toshiya , Morikawa Yoshio
Published: September 2009

Perinatal development of rat glomerulus was studied morphometrically. The percentage volumes of the five glomerular components (epithelial cells, capillary, mesangium, glomerular basement membrane, and Bowman’s space) were determined by point counting and the surface area of glomerular basement membrane per unit volume of glomerulus was done by intercept counting. Percentage volume of Bowman’s space was significantly decreased between days 20 and 21 of gestation, indicating the rapid growth of glomerular tuft during the prenatal period. Though both the length of glomerular capillary per unit volume of glomerulus (Lv) and surface area of glomerular basement membrane per unit volume of glomerulus were gradually increased from fetal day 20 to neonatal day 3, remarkable increase in Lv was observed between fetal day 22 and neonatal day 1. This indicates that the rat glomerulus develops rapidly during this period to adapt to extrauterine environment after birth.
Furosemide Increases Total Calcium in Kidney and Cytoplasmic Free Calcium in Blood Mononuclear Cells of Guinea Pigs
Authors: Tsao Peter W. , Klip Amira , Radde Ingeborg C.
Published: September 2009

Nephrocalcinosis has been observed in premature infants treated with furosemide. To see whether furosemide-induced renal calcium accumulation is reflected in easily accessible extrarenal cells, we measured cytosolic free calcium ([Ca2+]i) in blood mononuclear cells and kidney tissue calcium of guinea pigs chronically treated with furosemide. At week 0, the mean [Ca2+]i in blood mononuclear cells using the fluorescent indicator quin2 was 105 ± 4 nM. After 2 weeks of treatment with furosemide, the high dosage (10 or 20 mg/ kg/day) caused a significant increase in [Ca2+]i. There was no change in cell volume after 1 or 2 weeks of treatment with furosemide at this dosage. The kidney total calcium concentration and histological calcium accumulation increased with increasing furosemide dosages. These observations suggest that calcium accumulation in blood mononuclear cells may reflect the calcium accumulation in the kidney after furosemide treatment.
1,25(OH)2D3 Stimulates Phospholipid Biosynthesis and Surfactant Release in Fetal Rat Lung Explants
Authors: Marin L. , Dufour M.E. , Tordet C. , Nguyen M.
Published: September 2009

Lung tissue from 18-day-old rat fetuses was cultured in the presence of 1,25-dihydroxyvitamin D3 – 1,25(OH)2D3 –– (10––9M) and dexamethasone (10––7M) for 48 h. 1,25(OH)2D3 increased the lung content in phospholipids more specifically related to lung surfactant, phosphatidylcholine and phosphatidylglycerol. This increase was similar to that observed with dexamethasone. In addition, unlike dexamethasone, 1,25(OH)2D3 stimulated the surfactant release into luminal spaces, as evidenced by light and electron microscopy. Thus, vitamin D3 might represent an additional factor controlling fetal lung maturation by stimulating phospholipid synthesis and surfactant release from type II cells.
Inorganic Sulfate Metabolism in the Very Low Birthweight Infant
Authors: Cole David E.C. , Evans Jacquelyn R. , Raad May , Hamilton David C.
Published: September 2009

The effect of vitamin D supplementation on inorganic sulfate metabolism was examined in very low birth weight (< 1,500 g) infants at biweekly intervals after birth until 6 weeks of postnatal age. Baseline serum sulfate concentrations were significantly higher in all infants (471 ± 24 μmol/l, n = 80) than in adults (299 ± 25 μmol/l, n = 17). In controls, the levels did not change significantly over the ensuing 6 weeks, although serum creatinine declined. Urinary sulfate excretion rose significantly to near adult levels by 2 weeks. Both urine and serum sulfate were correlated with weight gain but not with estimated glomerular filtration rate, suggesting that factors other than renal clearance have a preponderant influence on serum sulfate in these infants. At 6 weeks, the mean serum sulfate in the high-dose group (receiving 2,170 ± 23 U/day of vitamin D, n = 41) was significantly higher than in controls (receiving 360 ± 22 U/day, n = 40). In all infants, there was a significant correlation (r = 0.36, p < 0.001) between serum sulfate and 25(OH)-vitamin D concentrations, but not other analytes or clinical variables, suggesting that vitamin D may be one of the factors modulating sulfate metabolism in the newborn period.
Effects of Changes in Oxygen Tension on Lipoxygenase Metabolites
Authors: Stuart Marie J. , Walenga Ronald W. , Setty B.N.Yamaja , Phelps Dale L.
Published: September 2009

The chronic phase of O2-induced retinopathy is characterized by retinal neovascularization. We have previously demonstrated that 15-hydroxy-5,8,11,13-eicosatetraenoic acid (15-HETE), a product of white cells, is proangiogenic. In this study, kittens exposed to in vivo hyperoxia produced increased amounts of 15-HETE. Nine litters of 30 kittens (aged 6–8 days) were used. Control kittens were left in room air; hyperoxic kittens were placed in 80% oxygen for 48 h; recovery kittens were returned to room air for 24 h following hyperoxic exposure. Following treatments, the animals were sacrified, and blood was evaluated for 15-HETE. Stimulated serum 15-HETE levels were assayed by high-performance liquid chromatography and GC-selected ion monitoring. While controls produced 0.48 ± 0.16 (SE) nmol/ml of 15-HETE, values in the hyperoxic and recovery animals were increased at 0.7 ± 0.2 and 0.68 ± 0.15 nmol/ml (p < 0.05 and p = 0.05, respectively). Increased production of this proangiogenic metabolite by WBCs (which can migrate out of blood vessels to set up extravascular angiogenic foci) may play a role in the genesis of the neovascularization process that occurs in response to oxygen-induced injury.
Reduced Platelet Counts in Neonatal Respiratory Distress Syndrome
Authors: Kohelet David , Perlman Max , Hanna Gila , Ballin Ami
Published: September 2009

Platelet counts were studied in preterm infants with the respiratory distress syndrome (RDS), excluding patients with significant perinatal and postnatal hypoxia. Counts fell to a nadir on day 4 (p < 0.000). Exploratory analysis indicated that severity of RDS (levels of FiO2 and mean airway pressure), airleak syndrome, grade of intraventricular hemorrhage (IVH) and low platelet count on day 1 were correlated with low platelet count on days 4 and 5. Further analysis by stepwise removal of each variable demonstrated statistically that FiO2 exerted a unique influence on the change in platelet count between day 1 and days 4/5 (p < 0.002). It is concluded that the severity of RDS is strongly associated with the fall in platelet count in the first few postnatal days. The effect of IVH on platelet count may be secondary to the effect of the RDS.
Cyclic Guanosine Monophosphate Metabolism in Human Amnion Cells Trisomic for Chromosome 21
Authors: Karlsson J.O.G. , Sjöstedt A. , Wahlström J. , Axelsson K.L. , Andersson R.G.G.
Published: September 2009

An extra copy of chromosome 21 a small chromosome or a specific segment of it, is the cause of the disorder known as Down’s syndrome (DS). Genes mapped to this chromosome include superoxide dismutase-1 (SOD-1) along with other enzymes. Gene dosage effects have been shown for some of these enzymes, including SOD-1. Increased SOD-1 has been suggested to stimulate the cGMP-forming enzyme, guanylate cyclase (GC). In the present study we have used amnion cells from DS subjects and normal subjects in order to indirectly test the effects of SOD-1 on the cGMP metabolism. We have measured the cAMP and cGMP content, SOD-1 activity, GC activity and cGMP phosphodiesterase (G-PDE) activity in amnion cells from DS subjects and normal subjects, respectively. The levels of cGMP in DS amnion cells were lower than in normal cells, although the SOD-1 activity was higher in DS amnion cells. Furthermore, the GC activity and the G-PDE activity were found to be lower in the trisomic cells. Our results do not support the suggestion that SOD-1 has a stimulatory effect on the GC activity.
Ontogenic Characterization of Type I and II Thyroxine 5′-Monodeiodinases in Brown Adipose Tissue from Fetal and Newborn Rabbits
Authors: Brzezińska-Ślebodzińska E. , Kapluk J.
Published: September 2009

The ontogenic changes in thyroxine 5′-monodeiodinase (5′-MD) activity were examined in brown adipose tissue (BAT) of fetal (26, 28 and 30 days of gestation) and newborn (1–14 days old) rabbits. A near-maximum stimulation of BAT 5′-MD activity was reached at 1 mM of dithiothreitol (DTT). The kinetics of 5′-MD inhibition by propylthiouracil (PTU) was uncompetitive in fetal and noncompetitive in neonatal tissue. In fetal tissue the Ki was 3.2 mM independently of DTT concentration, in newborns from 0.5 to 8.25 mM at 1–10 mM of DTT. An apparent Km constant for T4 to T3 conversion in BAT of fetal rabbit amounted to 0.2, 0.67, 1.9 and 2.0 μM in the presence of 1, 2, 5 and 10 mM DTT, respectively. In neonatal rabbits Km was constant (0.72 μM) in various DTT concentrations. The presence of 5′-MDI and 5′-MDII in BAT of fetal and neonatal rabbit was identified. Using iopanoic acid and amiodarone as inhibitors, a decrease in the 5′-MDII:5′-MDI ratio from 8.9 to 2.7 after birth was observed. Changes in 5′-MD activity with advancing age were not correlated with the SH group content in the BAT.
Development of Cholesterol Metabolism: The Effect of Diet Composition at Weaning
Authors: Hahn P. , Srubiski L.
Published: September 2009

Wistar rats were weaned on day 18 to a high fat (HF), high carbohydrate (HG) or high cholesterol (HCO 2%) diet. The activities of 3-hydroxy-3-methylglutaryl-CoA-reductase (HMGR), 7α-hydroxylase (7-OHase) and acyl-CoA-cholesterol-acyltransferase (ACAT) were assayed in the liver and small intestinal mucosa on days 21, 25 and 30 and in adult animals. An HF diet raises hepatic ACAT and HMGR activities in young rats but has the opposite effect in the gut. The cholesterol diet also raises hepatic ACAT activity, but less so than the HF diet. In the gut, however, the HCO diet invokes the greatest rise in ACAT of all the diets tested. Except in adult rats, the HG diet always raises hepatic ACAT activity more than the HCO diet or the Purina Chow. In the gut, however, activity is very low for the HG diet, much lower than for the HCO diet. Early feeding of the HCO diet for 12 days (from day 18 to 30) and refeeding the same diet from day 48 to 50 resulted in a subsequent response to the HCO diet that was different from that in rats which had never before been exposed to the HCO diet. It is concluded that early weaning results in changes in enzyme activities that depend on the composition of the diet fed at weaning and that this may also affect the later response to the same and perhaps other diets.
Age-Related Variations in Jejunum and Distal Colon Contractile Response to Thyrotropin-Releasing Hormone in vitro
Authors: Heitkemper M.M. , Bond E.F.
Published: September 2009

The effects of thyrotropin-releasing hormone (TRH) on the contractile activity of the proximal jejunum and distal colon of 3-, 7-, 14-, 21-, 28-, 50-day-old and adult male Sprague-Dawley rats were examined. Longitudinal segments were mounted in force displacement transducers and bathed in oxygenated, buffered Krebs’ solution. In the proximal jejunum TRH 10––6 M produced a tetrodotoxin (TTX)-sensitive tension increase in 3- to 14-day-old rats and a TTX-resistant biphasic response in older rats. TRH 10––6M produced a transient tension in the distal colon of rats ≤ 21 days old. Incubation with TRH 10––6M for 30min increased responsiveness to acetylcholine 10––7M in approximately 50% of tissues studied. Direct and indirect effects of TRH are developmentally determined.
Steroid Hormone May Modulate Hepatic Somatomedin C Production in Newborn Calves
Authors: Coxam V. , Davicco M.-J. , Durand D. , Bauchart D. , Opmeer F. , Barlet J.-P.
Published: September 2009

We have studied the possible influence of steroid hormones and a β-agonist (clembuterol) on hepatic insulin-like growth factor 1 (IGF1) production in young calves. For this purpose nine 20- to 40-day-old Holstein × Friesian male calves were fitted with chronically indwelling catheters in hepatic and portal veins and hepatic artery. Estradiol induced a simultaneous increase in plasma growth hormone (GH nmol/l) and IGF1 (nmol/l) levels (0.35 ± 0.05 vs. 0.10 ± 0.01 in control calves; 9.5 ± 1.0 vs. 5.9 ± 0.5 in controls, respectively). In the same way, 90 min after starting testosterone treatment, plasma GH levels increased from 0.21 ± 0.08 to 1.30 ± 0.40 while plasma IGF1 concentrations began to rise only 240 min after starting infusion (8.4 ± 1.0) to reach maximal values at 300 min (10.7 ± 1.1). Cortisol and clembuterol did not significantly modify either plasma GH levels or plasma IGF1 concentrations. Our results indicate that in young calves gonadal steroids exert their anabolic action through GH and IGF1.
Attempts for Identification of a Chorionic Gonadotrophin-Like Bioactivity in the Rat Placenta Which Stimulates the Testosterone Secretion of the Fetal Testis in vitro
Authors: Habert R. , Picon R.
Published: September 2009

The bioactivity of rat placental extracts was evaluated using a fetal rat testis testosterone (FRTT) bioassay. It is based on the measurement of the increase in testosterone secreted in vitro by testes from 18.5-day-old fetuses in response to the addition of placental extracts. Placentas obtained on days 11.5, 12.5, 13.5, 14.5, 15.5, 17.5 and 19.5 and homogenized with a Potter homogenizer (1 placenta per ml incubation medium), increased the secretion of testosterone by 460, 690, 500, 300, 220, 200 and 170%, respectively. These extracts showed a high proteolytic activity capable of suppressing the bioactivity of 0.8 ng/ml LH added prior to the extraction procedure. However, the bioactivity of the placental extracts did not increase after inhibiting placental proteases by the addition of benzamidine. Heat treatment did not decrease the bioactivity of placental extracts obtained without inhibition of proteases. Ultrafiltration of the placental extracts obtained with inhibition of the proteases showed that most of the bioactivity was dialyzable. The levels of bioactive material with molecular weights > 10,000 were very low (0.06 ng LH equivalent/placenta on day 12.5 and < 0.02 ng LH equivalent/placenta on day 14.5). These results suggest that rat placental bioactivity as measured with the FRTT bioassay is due, for the most part, to steroid precursors of testosterone and, for a very small part, to an LH/chorionic gonadotrophin (CG)-like molecule. Furthermore, after day 14.5, the placental LH/CG-like bioactivity, if it exists, is synthesized in too low levels to be able to control the testicular activity in the rat fetus.
Auditory Brainstem Response in Hyperbilirubinemic Rat: Part I
Authors: Kuriyama Masanori , Konishi Yukuo , Sudo Masakatsu
Published: September 2009

The effect of hyperbilirubinemia on the auditory brainstem response (ABR) of rats and its change by hyperosmolality were examined. The ABR wave I did not change significantly. In bilirubin-loaded rats, the latencies of wave II and IV were prolonged and the amplitudes decreased. Bilirubin injection damaged the central auditory pathway but the peripheral auditory pathway was spared. These ABR changes were reversible in the acute phase of hyperbilirubinemia. Mannitol administration hastened the appearance of the ABR peaks and the recovery of the changed ABR. This tendency was more remarkable in latency changes than in amplitude changes.
Transplacental Effect of Lead Compounds on Tissue Plasminogen Activator Activity, Plasminogen Activator Inhibition and Plasmin Inhibition
Authors: Smokovitis A. , Kokolis N. , Alexaki E. , Tsafaris F.
Published: September 2009

The transplacental effect of lead compounds (lead acetate and tetraethyl lead) on the tissue plasminogen activator activity (PAA), plasminogen activator inhibition (PAI) and plasmin inhibition (PI) was studied in the rat. The concentration of lead in organs of the newborn showed a great variation; the distribution of lead in the organs studied depended on the dose and the stage of gestation at injection. In each organ the concentration of lead was dose-dependent. In control specimens no lead could be detected. The tissue response of PAA, PAI and PI to the lead compounds also showed a great variation; however, there was no correlation between lead concentrations and PAA, PAI or PI responses. Changes of one or more of the parameters studied (PAA, PAI or PI) were noticed in lungs, liver, heart, brain and kidneys. The PAA was due to the tissue type plasminogen activator in all organs studied; in kidneys and lungs the urokinase type of plasminogen activator was also detected. Therefore, fetal tissue PAA, PAI and PI can be affected transplacentally by lead compounds.
Separation of the Umbilical Cord – Histological Findings
Authors: Oudesluys-Murphy A.M. , den Hollander J.C.
Published: September 2009

Even though the separation of the umbilical cord receives a great deal of interest, the process of cord separation has not been reported in the literature. A histological study of the umbilical area was carried out on 25 neonates who died within 7 days of birth (mean age at death 3 days). The umbilical cord itself became dried and mummified. Polymorphonuclear leucocytes infiltrated the areas between the mummifying cord stump and the vital tissues of the abdominal wall, forming a demarcation zone. No other leucocytes were present, and no bacteria were seen in any of the preparations studied.
Effect of Neuromuscular Blockade on Fetal Oxidative Metabolism
Authors: Wilkening Randall B. , Boyle David W.
Published: September 2009

Because fetal neuromuscular blockade has been used during cord blood sampling procedures to prevent fetal movement, we studied the effect of pancuronium bromide on fetal arterial concentrations of glucose, lactate, and oxygen and their umbilical uptake in 6 chronically prepared fetal sheep. We observed a significant increase in the arterial concentrations and decrease in the umbilical uptakes. We suggest that cord blood sampling procedures for fetal assessment of oxidative metabolism not be performed after fetal neuromuscular blockade so that data obtained might best reflect the unperturbed physiological condition of the fetus.
Lactate Movements in the Term Human Placenta in situ
Authors: Piquard François , Schaefer Adrien , Dellenbach Pierre , Haberey Pascal
Published: September 2009

Movements of lactate through the human placenta in situ were derived from maternal and fetal blood sampling performed under conditions that approximate as closely as possible the normal fetal metabolic state. It is reported that, at the end of pregnancy, the human fetus produces lactate which is transferred to the placenta. The actuality of this lactate transfer coupled with proton transfer is discussed taking into account the results of multiple linear regression analysis determined between the umbilical arterio-venous lactate differences and fetal and maternal lactate and proton concentrations. It is finally assumed that this lactate is partly metabolized in the placenta, the remaining part being transferred from the placenta to the mother.
Dependency of Doppler Parameters in the Anterior Cerebral Artery on Behavioural States in Preterm and Term Neonates
Authors: Jorch Gerhard , Huster Thomas , Rabe Heike
Published: September 2009

To investigate changes of intracerebral blood flow velocity correlated to different behavioural states, pulsed Doppler measurements were performed on anterior cerebral artery in 12 preterm and term neonates under polygraphic recordings and in view of the infants’ behavioural state. Under very strict definition of the behavioural states there were significant differences in the parameters Vm (+25%), Vd (+75%), and Vs (+11 %) in active compared to quiet sleep state. MABP was not significantly different in all examined behavioural states. From our results we conclude that in further Doppler studies the infants’ behavioural state at the time of measurement should be assessed carefully.
Effects of Adenosine and Its Analogues on Isolated Internal Carotid Arteries from Newborn and Adult Pigs
Authors: Laudignon Nicole , Aranda Jacob V. , Varma Daya R.
Published: September 2009

Vasorelaxant effects of adenosine and its analogues, 5′-N-(ethylcarboxamide) adenosine (NECA), N6-(l-phenylisopropyl)-adenosine (l-PIA) and N6-cyclohexyladenosine (CHA), on isolated internal carotid arteries from newborn (1–3 days) and adult (6 months) pigs were compared. The order of vasorelaxant potencies of adenosines was: NECA > l-PIA > adenosine > CHA for the adult arteries and NECA > l-PIA > adenosine = CHA for the newborn arteries. Sensitivities of vessels from the newborn and mature animals to CHA and l-PIA did not differ. However, carotid arteries from the newborn pigs were less sensitive to NECA and adenosine than the adult arteries (p < 0.05). Theophylline caused an approximately 3-fold shift to the right of the relaxant concentration-response curves to all the four adenosines on arteries from pigs of both age groups. These data suggest that adenosine is not as effective a vasodilator in the newborn as it is in the adult.
Neonatal and Adult Patterns of Lectin Binding to Rat Small Intestinal Microvillus Membranes
Authors: Stern Martin , Gellermann Barbara , Schall Inke
Published: September 2009

To investigate postnatal developmental changes of rat small intestinal microvillus membrane (MVM) sugar components, binding studies were done using peanut agglutinin (PNA) and soybean agglutinin (SBA). MVM were prepared from rats of different ages (newborns to 12 weeks). The Airfuge® method was used for separation of unbound material. Characteristics of sugar ligand specificity were different for PNA and SBA, although D(+)galactose was used as an inhibitor for both lectins. Concentration curves and Scatchard plots showed partial saturation of total binding, and at least two groups of MVM ligands. Differences in lectin binding between newborn and adult MVM were opposite for PNA and SBA (newborns bound more PNA, but less SBA). During the first few postnatal weeks in rats, SBA binding changed early, and PNA binding exhibited an intermediate change, not related to weaning. Changes in MVM glycoproteins shown by lectin binding appear to be part of a complex postnatal maturational process in rats, involving different biochemical, functional, and biophysical membrane characteristics
Effects of Maternal Hyperoxygenation on Atrioventricular Velocity Waveforms in Healthy and Growth-Retarded Fetuses
Authors: Rizzo Giuseppe , Arduini Domenico , Romanini Carlo , Mancuso Salvatore
Published: September 2009

In order to assess whether maternal hyperoxygenation induces modifications of Doppler-measured velocity waveforms across atrioventricular valves, 15 healthy and 15 growth-retarded fetuses were studied in basal conditions and during the maternal administration of 60% humidified oxygen. Recordings were performed at 5-min intervals before, during and after maternal oxygen administration. In basal conditions, growth-retarded fetuses exhibited significantly lower ratios between the velocities during early passive ventricular filling and active ventricular filling (E/A ratio) at the level of both mitral and tricuspid valves when compared to healthy fetuses. Furthermore in healthy fetuses the velocity time integral across the tricuspid valve always slightly exceeded that across the mitral valve, whilst growth-retarded fetuses showed an inversed ratio between these velocities. During oxygen administration no changes were found between the two groups of fetuses with regard to the E/A ratios. Similarly the velocity time integrals were unaffected by oxygen administration in the healthy fetuses. Besides growth-retarded fetuses exhibited significant temporary modifications during oxygen administration as expressed by an increase in the velocity time integral across the mitral valve associated with a decrease of that across the tricuspid. These changes result in an inversion of the ratio between transtricuspid and transmitral velocity time integrals reaching values similar to those of healthy fetuses. Short-term oxygen administration affects the intracardiac flow redistribution present in growth-retarded fetuses bringing it to a pattern similar to that of healthy fetuses whereas the E/A ratios were not affected by the treatment.
An Explanation for Ketogenesis by the Intestine of the Suckling Rat: The Presence of an Active Hydroxymethylglutaryl-Coenzyme A Pathway
Authors: Békési Andrea , Williamson Dermot H.
Published: September 2009

Hydroxymethylglutaryl-coenzyme A (HMG-CoA) synthase is present in the mucosa of the proximal small intestine of the suckling rat, as are acetoacetyl-CoA thiolase and HMG-CoA lyase. At weaning the activity of HMG-CoA synthase decreases by 90%. This change in activity parallels a change in the rate of ketogenesis in vitro by mucosal scrapings. Starvation of the pups decreases the rate of ketogenesis. It is concluded that the mucosa of the developing rat has an active HMG-CoA pathway and that there may be a relationship between intestinal ketogenesis and milk consumption in the suckling rat. The possible physiological significance of this finding is discussed.
Cardiac and Respiratory Responses to Esophageal Dilatation during REM Sleep in Human Infants
Authors: Ramet J. , Praud J.-P. , D’Allest A.-M. , Dehan M. , Guilleminault C. , Gaultier C.
Published: September 2009

Forty-one preterm and fullterm infants (26.5–40.5 weeks gestational age and 31.5–50 weeks postconceptional age) free from neurologic and cardiopulmonary disease at the time of testing underwent a standardized esophageal dilatation test (EDT) during polygraphically controlled REM sleep. RR interval and total duration of the respiratory cycle (TTOT) were measured (1) during the 60s preceding the EDT, i.e. mean control RR and mean control TTOT; (2) during EDT. Percent RR (%RR) was defined as the longest RR interval in milliseconds during EDT divided by mean control RR in milliseconds multiplied by 100, and percent TTOT (%TTOT) as the longest TTOT in seconds during EDT divided by mean control TTOT in seconds multiplied by 100. EDT provoked prolongation of both RR interval and TTOT·%RR decreased significantly with advancing gestational age (p < 0.003), and %TTOT with advancing postconceptional age (p < 0.003), indicating that both cardiac and respiratory responses to an EDT challenge are blunted with maturation.
Hypersomatotropism in the Dysmature Infant at Term and Preterm Birth
Authors: de Zegher F. , Kimpen J. , Raus J. , Vanderschueren-Lodeweyckx M.
Published: September 2009

Growth hormone (GH) concentrations were measured in cord serum of small (< 2.4 kg), appropriate (3.4 ± 0.1 kg) and large (> 4.4 kg) infants born at term (38–42 weeks), and in cord serum of prematurely born twins (28–36 weeks) which were either appropriate ( > P10) or small ( < P10) for gestational age. Cord serum GH levels were found to be significantly elevated in small for gestational age infants, both at term and preterm birth. In view of the insulin-antagonizing action of fetal GH, these results further support a homeostatic function for GH in the late-gestational human fetus.
Effect of Acetazolamide on Cerebral Blood Flow Velocity and CO2 Elimination in Normotensive and Hypotensive Newborn Piglets
Authors: Thoresen Marianne , Whitelaw Andrew
Published: September 2009

The objectives of this study were to measure the effect of acetazolamide on cerebral circulation, pulmonary elimination of CO2 and cerebrovascular response to hypotension in newborn piglets. Eighteen anaesthetized newborn piglets were studied. A fontanelle was surgically created and the cerebral blood flow velocity (CBFV) in an intracranial artery measured by a computerized Doppler system. In 8 piglets, 30 ml/kg of blood was removed to produce hypotension before the administration of acetazolamide. Acetazolamide (50 mg/kg i.v.) given to normotensive piglets consistently produced a large increase in CBFV (median 45% by 5 min) with no change in mean arterial blood pressure or heart rate. The rise in CBFV was negatively correlated with the starting partial pressure of CO2 in arterial blood. Within 1 min of administration of acetazolamide, the end-expiratory CO2 pressure started to fall (mean fall 1.4 kPa), and the partial pressure of CO2 in the arterial blood started to rise (mean rise 2.0 kPa), despite the controlled ventilation being unchanged. Acetazolamide had no effect on CBFV in the hypotensive piglet. It seems likely that acetazolamide produces cerebral vasodilatation by inhibiting the elimination of CO2 In hypotension, there is maximal cerebral vasodilatation, and acetazolamide cannot increase CBFV further. The interference of acetazolamide with CO2 elimination could seriously limit its use in the treatment of hydrocephalus in preterm infants.