bluuebunny/crossref_metadata_2025 huggingface dataset:
Trace Elements and Antibacterial Activity in Amniotic Fluid
Authors: Honkonen Erkki , Näntö Veikko , Hyörä Hanna , Vuorinen Klas , Erkkola Risto
Published: September 2009

Antibacterial activity and trace element concentrations in amniotic fluid (AF) were determined in a population of 39 pregnant women in the second half of gestation. Antibacterial activity in each AF was measured by a spectrophotometric micromethod after 18 h incubation at 37 °C using Escherichia coli K 12 as a reference bacterium. Concentrations of zinc, iron, copper, calcium, potassium and bromine were measured by particle-induced X-ray emission method and the zinc concentration was also measured by atomic absorption spectrophotometry. Phosphate concentration was determined by direct albumin adding method. In AFs with good antibacterial activity significantly lower concentrations of potassium and bromine were found when compared to AFs with lower antibacterial activity. Concentrations of zinc, iron, copper, calcium or phosphate did not correlate with antibacterial activity in AF.
Correlations between Digoxin-Like Immunoreactivity and Electrolyte Values in Urinary Samples of Newborns
Authors: Clerico Aldo , Boldrini Antonio , Del Chicca Maria Grazia , Biver Pascal , Fantoni Massimo , Mezzasalma Lorena , Fassorra Carlo , Cipolloni Carlo
Published: September 2009

Elevated levels of a group of substances with digoxin-like immunoreactivity (DLIS) are present in biological fluids of newborns. These endogenous substances could also have the biological properties of cardiac glycosides, such as natriuretic and vasoconstrictor activity. Therefore, DLIS could be involved in electrolyte and volume regulation in infants. We measured DLIS, electrolyte (Na+, K+, Cl––) and creatinine concentrations in 157 urine samples collected from full-term and preterm infants, with the aim to establish if a correlation exists between the urinary DLIS levels and the respective values of these electrolytes. Significant and positive correlations were found between the urinary concentrations of DLIS and electrolytes. In addition, electrolyte values correlated significantly between themselves. DLIS, K+ and Cl–– values correlated positively with urinary creatinine concentrations (n = 142). A significant multiple correlation was found among DLIS concentrations and creatinine and Cl–– values. We also studied the DLIS concentrations in serum samples collected at birth in peripheral blood of the mothers and in umbilical cord and gastric aspirate of 5 full-term infants. We observed that DLIS values in newborns are significantly higher than the respective values of the mothers. In conclusion, our data do not demonstrate a clear relationship between DLIS and electrolyte concentrations in urine samples of newborns. Further investigations are necessary to elucidate the biochemical and physiological properties of DLIS.
Moderate Hyperbilirubinemia Does Not Influence the Behavior of Jaundiced Infants
Authors: Paludetto Roberto , Mansi Giuseppina , Rinaldi Patrizia , Ariola Paola , Cascioli Concetta F.
Published: September 2009

Several recent reports have described short-term effects of moderate hyperbilirubinemia, and have questioned the treatment protocols of neonatal jaundice. However, most of these studies were not designed to investigate the effects of hyperbilirubinemia per se and could have been influenced by phototherapy. We have evaluated with the Brazelton Neonatal Behavioral Scale 17 moderately jaundiced term 3-day-old infants (mean bilirubin level 10.6 mg/100 ml, range 8.4–14.3) not treated with phototherapy and 17 not jaundiced matched subjects; 14 jaundiced 4-day-old subjects (mean bilirubin level 10.4 mg/l00 ml, range 8.4–12.9) and 14 not jaundiced matched subjects; 10 ex-jaundiced 1-month-old infants (mean bilirubin level 11.5 mg/100 ml, range 9.1–15.9) and 10 matched not jaundiced infants. No differences were found between jaundiced infants and not jaundiced infants. Our data indicate that moderate levels of hyperbilirubinemia not treated with phototherapy do not influence neonatal behavior. Hence, more aggressive treatment is not justified, at least in term infants.
The Sensitivity of the Fetal Rat Adrenal Gland to Adrenocorticotropic Hormone in vivo and in vitro
Authors: Yamamoto Masako , Arishima Kazuyoshi , Eguchi Yasunobu
Published: September 2009

Rat fetuses were treated with 1 IU ACTH on day 16 or 17 of gestation and autopsied on the next day. Other fetuses of the same litter were treated with saline alone. The adrenal glands of ACTH-treated fetuses were significantly heavier than those of saline-treated fetuses and of intact controls in every experimental period. These changes in the weight of fetal adrenal glands reflect histologically on changes in the size of adrenocortical cells which were enlarged in response to injected ACTH. Adrenal glands from rat fetuses of different ages were explanted to organ cultures for 2 days, in medium with or without ACTH added. The 13-day adrenal glands were not able to respond to ACTH, but the response appeared abruptly in the 14-day adrenal glands, judging from the increased cell size in histological sections. The overall results suggest that the fetal adrenal gland begins to respond to ACTH from day 14 of gestation.
Role of Thyrotropin-Releasing Hormone in Thyroid-Stimulating Hormone and Growth Hormone Regulation during Postnatal Maturation in Female Wistar Rats
Authors: Štrbák Vladimir , Angyal Robert , Jurčovičová Jana , Randušková Anna
Published: September 2009

The role of endogenous thyrotropin-releasing hormone (TRH) in the control of pituitary thyroid-stimulating hormone (TSH) and growth hormone (GH) secrection was studied during postnatal maturation in female Wistar rats. Half of the sucklings in each litter was treated intraperitoneally with either specific rabbit antiserum against TRH or normal rabbit serum (0.1–0.3 ml according to age). All animals were decapitated after 2 h. The presence of anti-TRH activity was checked as a binding of labelled TRH with plasma of the experimental animals. Immunoneutralization of endogenous TRH resulted in a decrease of plasma TSH in 3- to 15-day-old female pups as compared to control littermates. No effect of TRH antibody injection was seen at the ages of 1, 21, 30 and 70 days despite the presence of excess antibody in the plasma. A profound effect of TRH antibody on plasma TSH was seen again at the age of 100 days. Plasma GH in the same animals exhibited a paradoxical increase after TRH immunoneutralization at the age of 5 and 8 days, a decrease was found at the age of 21 days. It was concluded that hypothalamic TRH control of TSH secrection matures early in Wistar rats. Hypothalamic secrection of TRH at the ages of 1, 21, 30, and 70 days is low and(or) its role in TSH regulation is masked by other regulating factors. TRH may play a dual role in the regulation of GH secretion during the postnatal period.
Effect of Metoclopramide Treatment on Thyrotropin and Prolactin Levels in Sick Neonates
Authors: Ruppert F. , Sulyok E. , Sárkány I. , Zámbó K. , Csaba I.F.
Published: September 2009

The present study was carried out to define whether dopaminergic mechanisms contribute to the regulation of thyrotropin (TSH) and prolactin PRL release in the immediate neonatal period. 14 full-term neonates with a mean birth weight of 3,240 g and a mean gestational age of 39.1 weeks were administered metoclopramide (MTC), a specific dopamine antagonist, in a dose of 0.1 mg/kg/day to treat delayed gastric emptying, regurgitation and abdominal distension. Prior to and after 3-day MTC administration, blood samples were taken to determine serum TSH and PRL levels using a radioimmunoassay method. It has been demonstrated that in response to MTC administration PRL increased significantly from 4,010 ± 383 to 5,478 ± 441 mU/1 (p < 0.01), while TSH showed only a tendency to rise independent of the pretreatment hormone levels (from 2.85 ± 0.44 to 3.06 ± 0.38 mU/L. In healthy control infants and in those infants with similar functional gastrointestinal disturbances who were treated without MTC, serum PRL levels fell significantly from days 3–4 to days 6–7, serum TSH, triiodothyronine and free thyroxine, however, remained unaltered. It is concluded that dopaminergic inhibitory mechanisms may .be involved in the control of pituitary PRL and TSH release already in the neonatal period.
Changes in Plasma Amino Acids in the Developing Chick
Authors: Frampton R.J. , Yardley R.W. , MacMahon R.A.
Published: September 2009

We have sampled arterial blood from chicken embryos during development and measured the changes in plasma amino acids from mid-gestation to hatching. During gestation, several amino acids rise to a peak concentration at 16 days and fall prior to hatching. After hatching, most amino acids fall, although the plasma concentrations of aspartate, glutamate and taurine rise significantly.
Drugs and Acute Renal Insufficiency in the Neonate
Authors: Gouyon J.-B. , Guignard J.-P.
Published: September 2009

Oliguria in the neonate usually reflects a fall in glomerular filtration rate (GFR) secondary to prerenal disturbances such as hypovolemia, hypotension, hypoxemia and cardiac failure, or to vasoactive drugs such as indomethacin and tolazoline. The action of such drugs on renal function is reviewed, as well as the pharmacological measures that can be tried to prevent or blunt their renal side effects. The efficacy and side effects of dopamine, furosemide and mannitol, frequently used in oliguric states due to either prerenal disturbances or to vasoactive drugs, are discussed. It is concluded that available data in newborn infants do not definitely prove the efficacy of dopamine and furosemide in preventing acute renal insufficiency and that, in neonates with established oliguria, administration of mannitol, dopamine and/or furosemide can be tried, with little hope, however, of markedly improving GFR.
Pharmacologic Probing of Renal Development in the Neonatal Rat
Authors: Gray Jacqueline A. , Kavlock Robert J.
Published: September 2009

This study was designed to examine the ontogeny of renal functions in the neonatal rat using various pharmacologic agents as probes. The renal responses of 2-, 6-, and 10-day-old rats to diuretic agents known to act on proximal tubules, loops of Henle and distal tubules were assessed. These included acetazolamide, furosemide, mercaptomerin, chlorothiazide and amiloride. Following administration of a diuretic agent, urine was collected at 90-min intervals for 6 h and urine volume, osmolality, chloride and pH were measured. Acetazolamide, furosemide, chlorothiazide and amiloride induced diuresis at each age indicating that the respective reabsorptive mechanisms were present and functional by 2 days of age. At all ages furosemide evoked a maximal response in eliminating the interstitial fluid gradient as indicated by the formation of an isosmotic urine in treated pups. However, the volume of the diuresis at 2 days of age was half those at 6 and 10 days, reflecting enhanced activity of the countercurrent multiplication apparatus in the maturing pups. Administration of mercaptomerin did not produce pharmacologic diuresis, but rather resulted in acute renal failure; although the nephrotoxicity was to a lesser extent in 2-day-old pups. The ability of the neonatal rat to respond to these pharmacologic probes demonstrates that the integrity of these renal functions is established in this species early in postnatal life.
Enterocyte Migration in the Foetal Sheep Small Intestine
Authors: Trahair J.F. , Perry R.A. , Silver M. , Robinson P.M.
Published: September 2009

The migration of enterocytes was studied in the small intestine of foetal sheep at 115 and 136 days of gestation in utero. The speed of migration in all cases was slower than that reported in the adult. At 115 days, the migration rate was 4.88 and 4.96 percent villus height/day for the proximal and distal small intestine, respectively. At 136 days, the migration rate was significantly increased (p < 0.05) to 12.0 for the proximal and to 8.5%, for the distal small intestine. Rates of villus length increase were between 0.007 and 0.012 mm/day over the time course studied. The migration rates, expressed as millimeters per day, were between 0.23 and 0.76 mm/day, hence the rate of migration was much greater (between 3 and 16 times) than the villus growth rate.
Developmental Toxicity of NN1-Bis(Dichloroacetyl)-1,8-Octamethylene Diamine: Effects of in utero Exposure on the Postnatal Murine Immune System
Authors: Porter J.F. , Schmidt R.R.
Published: September 2009

Oral gavage of pregnant C57BL/6J mice with N, N1-bis(dichloroacetyl)-1,8-octa-methylene diamine on day 10 of gestation alters the morphology of a primary lymphoid organ, i.e., thymus, of the offspring when observed at 36 days of postnatal life. Thymuses obtained from the experimental offspring exhibited an overall reduction in size and cortical hypoplasia. Morphology of the spleen, a secondary lymphoid organ, is also affected in the offspring obtained from dams treated with this compound on day 10 of gestation. Spleens exhibited diffusely distributed white pulp areas compared to the distinctly nodular appearance in control spleens. Furthermore, it has been shown for the first time that prenatal administration of N, N1-bis(dichloroacetyl)-1,8-octamethylene diamine on day 12 of gestation alters the functional responsiveness of splenocytes obtained from the offspring of treated dams to a variety of mitogens when examined at 3, 5, 9 and 16 weeks of postnatal life. Administration of the compound prenatally on day 12 of gestation did not alter the postnatal morphological appearance of either thymus or spleen.
Body Water Estimates in Intrauterine-Growth-Retarded versus Normally Grown Baboon Neonates
Authors: Brans Yves W. , Kuehl Thomas J. , Hayashi Robert H. , Andrew Donna S.
Published: September 2009

Body water content and distribution were compared in 6 intrauterine-growth-retarded and 10 normally grown term baboon neonates. Growth-retarded baboons had larger mean antipyrine and corrected bromide spaces than their normally grown peers. Other water compartments were on the average similar in both groups. This pattern of comparisons is identical to that observed between normally grown and growth-retarded human neonates. Mean estimates for the various body water volumes were strikingly similar for growth-retarded neonates in baboons and humans.
Effect of Hypothyroidism during Gestation and in the Suckling Period on Cholesterol and Carnitine Metabolism in the Rat
Authors: Hahn P.
Published: September 2009

Propylthiouracil (PTU; 0.05%) was added to the drinking water of rats of various ages and their response was monitored. PTU resulted in reduced body weights in both fetuses and young rats 0–30 days old. Plasma cholesterol levels were elevated and the activities of hepatic 3-hydroxy-3-methyl-glutaryl CoA reductase (HMGCoAR) and 7-alpha-hydroxylase were decreased if PTU was present in the water up to the time of death. However, if no PTU was present for some time before death, this effect was no longer observed. Plasma total carnitine levels were always suppressed by PTU and appeared the most sensitive indicator of PTU action. Intestinal acylcholesterol acyltransferase (ACAT) activity was elevated nearly 5-fold, while intestinal HMGCoAR activity was only slightly and occasionally depressed.
Effects of Neonatally Administered Chlorpromazine and Reserpine on the Responsiveness of Rat Hepatic Drug-Metabolising Enzymes to Testosterone in Adult Life
Authors: Finnen Michael J. , Hassall Kenneth A.
Published: September 2009

The effects of neonatally administered chlorpromazine and reserpine on the response of rat hepatic drug-metabolising enzymes to testosterone in adult life have been investigated using the chlorinated cyclodiene substrate DME. Neonatal treatment with chlorpromazine and reserpine had effects on the metabolism of DME similar to, but not as pronounced as, those of castration when adult. The effects of adult castration of male rats on hepatic microsomal metabolism of DME were fully reversed by treatment with testosterone propionate, with metabolism being restored to that of a control intact male. However, testosterone propionate treatment of either intact or castrated adult males that had received neonatal reserpine or chlorpromazine did not restore levels of metabolism to those characteristic of control adult male rats. These results suggest that neonatally administered chlorpromazine and reserpine alter the sensitivity of hepatic drug-metabolising enzymes to the actions of testosterone in adult life.
Glutathione Peroxidase Activity in Cord Blood: Effects of Fetal Sex and Maternal Smoking
Authors: Bannon M. , Halliday H.L. , McMaster Dorothy
Published: September 2009

Glutathione peroxidase activity was estimated in the cord blood of 47 newborn infants. In 23 cases corresponding maternal glutathione peroxidase activities were measured at time of delivery and compared with 23 non-pregnant women of the same age. Mean cord blood activity was 23.6 ± 4.8 IU/g Hb at 37 °C. Maternal smoking and male fetal sex were associated with significantly lower fetal glutathione peroxidase activity. Maternal levels (33.0 ± 5.0 IU/g Hb) were significantly higher than those in cord blood (p < 0.001) but were the same as those for non-pregnant women. Maternal to cord blood level ratio was 1.5:1.
Effect of Phenobarbital on Cerebral Blood Flow in the Newborn Piglet under Stress
Authors: Laudignon N. , Chemtob S. , Beharry K. , Rex J. , Aranda J.V.
Published: September 2009

Heart rate, cardiac output, mean arterial blood pressure (MABP), and cerebral blood flow (CBF) were measured in 12 newborn piglets (6 controls and 6 pretreated with 20 mg/kg phenobarbital), under two different stresses: pain stimulation and intravenous injection of 2.5 mg/kg phenylephrine. Phenobarbital prevented pain-induced tachycardia (p < 0.05 versus controls) but failed to prevent hemodynamic changes induced by phenylephrine. CBF remained relatively constant throughout the study. A better correlation between cerebral vascular resistance and MABP was noted in the phenobarbital group (r = 0.58, p < 0.01) than in the controls (r = 0.15, p = NS), suggesting that phenobarbital potentiates the vasoconstrictor effect of catecholamines.
Lipoprotein Metabolism in Pregnancy, Fat Transport to the Fetus, and the Effects of Diabetes
Authors: Knopp Robert H. , Warth Maria R. , Charles David , Childs Marian , Li Job R. , Mabuchi Hiroshi , Van Allen Margot I.
Published: September 2009

The objective of this paper is to review the extent and mechanisms of lipoprotein alterations in pregnancy, present new data relating to placental lipid transport in. normal humans and diabetic animals and consider possible effects on fetal growth and development in normal and diabetic pregnancy. The concentration of all lipoprotein fractions increases during pregnancy. VLDL cholesterol and triglyceride increase 2.5-fold over prepregnancy levels and LDL cholesterol increases 1.6-fold, all with peak levels at term. HDL cholesterol is maximally increased in midgestation by 1.45-fold and subsequently declines to 1.15-fold at term. The mechanisms of these lipoprotein changes have not been studied in humans but the hypertriglyceridemia in animal models is related to enhanced VLDL entry into the circulation. In addition, diminished adipose tissue lipoprotein lipase (LPL) activity in late gestation may cause a rerouting of triglyceride fatty acids to other tissues such as muscle and uterus for oxidation, rather than storage, since triglyceride transport is not reduced in pregnancy. All of these changes appear to be sex hormone mediated. In diabetic pregnancies, the available data indicate that triglyceride concentrations are increased and HDL cholesterol concentrations are decreased with reference to lipoproteins in nondiabetic pregnant women. Previously unpublished data show that a transplacental FFA gradient exists across the umbilical circulation in the direction of the fetus and is proportional to the maternal FFA concentration. No gradient is seen for triglyceride or total plasma cholesterol. However, transport of unmeasured amounts of triglyceride fatty acids may still occur via placental LPL and be exaggerated in diabetes where LPL declines in adipose tissue but not in placenta. The mechanism of transplacental cholesterol transport remains to be defined. Preliminary studies suggest that it depends on HDL as well as LDL since both can provide cholesterol for placental progesterone synthesis. In addition, fetal weight and length are associated with maternal apoproteins A-I and A-II, both major apoproteins of HDL. By lowering HDL in pregnancy, diabetes mellitus could negatively affect these relationships. In conclusion, sex hormone mediated modifications of lipoprotein physiology are described in pregnancy which may enhance triglyceride fatty acid transport to muscle for oxidation and LDL and HDL cholesterol delivery to growing maternal and fetal tissues, a process that diabetes could globally disrupt.
Phenotypic Heterogeneity within the Circulating Human Neonatal T4-Positive T Cell Subset
Authors: Bertotto A. , De Felicis Arcangeli C. , Gerli R. , Spinozzi F. , Marinelli I. , Fabietti G. , Crupi S. , Gentili A.M. , Vaccaro R.
Published: September 2009

An indirect immunofluorescence staining technique was employed to evaluate the TQ1 and 5/9 monoclonal antibody lymphocyte reactivity in 10 cord blood mononuclear cell (MC) preparations enriched of E-rosette-forming cells (E+). Ten adult E+ MC populations were used as controls. Unfractionated T4+ cord and adult MC positively selected by panning procedure were also assayed. The results of these experiments, taken together, suggest that there is an overexpanded neonatal T cell subset which displays a previously unrecognized immunophenotype (T4+, TQ1+, 5/9+). Whether these lymphocytes are involved in the well-known fetal-maternal immunosuppressive mechanisms of whether they are a further example of neonatal phenotypic immaturity remains to be elucidated.
The Preferred Environmental Temperature of Newborn Rabbits
Authors: Hull D. , Hull J. , Vinter J.
Published: September 2009

The preferred environmental temperature (TE) and rates of oxygen consumption (VO2) around the thermal neutral range were measured in rabbits on the day of birth and 2, 7 and 14 days after birth. On day 0, the preferred TE was 38.0 ± 0.8 °C, and it fell to 30.4 ± 0.5 °C by day 14. Day-0 rabbits kept for 1 h in a warm (41 °C), neutral (39 °C) or cool (28 °C) environment selected a different TE at 39.8, 39.5 and 37.3 °C, giving colonic temperatures (Tc) of 40.8, 39.9 and 37.7 °C, respectively. A similar phenomenon occurred on day 2, but not on day 7. It was concluded that newborn rabbits select a TE to match that which they experienced in utero and that this preferred TE changes after birth depending on the temperature of their surroundings and the development of their thermoregulatory control.
Effect of Weaning on Different Diets on Hepatic Gluconeogenesis in the Rat
Authors: Decaux J.F. , Ferré P. , Girard J.
Published: September 2009

The capacity of gluconeogenesis from lactate (10 mmol/l) was studied on isolated hepatocytes in 15-day-old suckling and in 28-day-old rats weaned at the age of 19 days on various diets. Weaning on a high-fat carbohydrate-free diet allowed to maintain a high gluconeogenic rate. By contrast, as soon as the carbohydrate content of the weaning diet was sufficient to meet the glucose needs of the newborn, the gluconeogenic capacity was reduced. The amount of fat in the weaning diet had no influence on the gluconeogenic capacity. Changes in the hepatic gluconeogenic rate at weaning were inversely correlated with the plasma insulin/glucagon molar ratio.
Attenuation of Postnatal Hypoxia in the Premature Newborn Rat by Maternal Treatment with Dexamethasone: Its Relationship with Lung Phospholipid Content
Authors: Juanes María C. , Arizmendi Carmen , Medina José M.
Published: September 2009

The effect of maternal treatment with dexamethasone on blood PO2, PCO2, pH and lactate concentrations and on lung phospholipid content in premature newborn rats during the early neonatal period was studied. The postnatal hypoxia shown by premature newborn rats was prevented by this treatment. Postnatal hypercapnia was longer in premature newborns though it was partially shortened by the treatment. Resistance to blood lactate removal shown by premature newborns was partially prevented by the treatment. The premature newborns showed significantly lower lung phospholipid concentrations than term-delivered newborn animals. Maternal treatment with dexamethasone increased lung phospholipid concentrations which reached values close to those found in term newborns. Our results suggest that maternal treatment with dexamethasone prevents postnatal hypoxia in the premature newborn rat by increasing the lung phospholipid content, which results in an enhancement of oxygen transfer through the alveolar membranes and the attenuation of hyperlactiacidemia.
Cord Blood Levels of Corticotropin-Releasing Factor
Authors: Nagashima Kanji , Yagi Hideki , Yunoki Hitosi , Noji Takashi , Kuroume Takayosi
Published: September 2009

The levels of corticotropin-releasing factor (CRF) in the cord blood from 34 infants were determined by radioimmunoassay. All infants were born by vaginal delivery after an uneventful pregnancy. Levels of cortisol, dehydroepiandrosterone sulfate and ACTH were high in the cord blood. CRF levels (mean ± SD) were 100.5 ± 31.7 and 44.5 ± 7.8 pg/ml, respectively, in cord blood and in controls (healthy prepubertal children, n = 10). Although the origin of CRF in peripheral circulation has not been clarified, we speculate that the high adrenocortical steroid synthesis of the fetus might be a consequence of high CRF levels in fetal circulation.
Wavelength Dependence of the Geometric and Structural Photoisomerization of Bilirubin Bound to Human Serum Albumin
Authors: Itoh Susumu , Onishi Shoju , Isobe Kenichi , Manabe Masahiw , Yamakawa Takeshi
Published: September 2009

The two quantitatively important photoisomers in bilirubin metabolism during phototherapy are (ZE)-bilirubin and (EZ)-cyclobilirubin. We describe in vitro studies on the wavelength dependence for the geometric (Δ4Z, Δ15Z → Δ4Z, Δ15E) and structural (endovinyl cyclization) photoisomerization of bilirubin bound to human serum albumin by a high performance liquid chromatography method. For the geometric photoisomerization from (ZZ)-bilirubin to (ZE)-bilirubin, the most effective wavelength in vitro was 410 nm. For the structural photoisomerization, green light at 510 nm is the most efficient for causing cyclization of (ZZ)-bilirubin to (EZ)-cyclobilirubin via (EZ)-bilirubin and this may depend on a larger cross-section of (EZ)-bilirubin than (ZZ)-bilirubin in this spectral region and/or on a larger quantum yield for cyclization than geometric photoisomerization.
Effect of Insulin on Glucose/Oxygen and Lactate/Oxygen Quotients across the Hindlimb of Fetal Lambs
Authors: Wilkening Randall B. , Molina Richard D. , Battaglia Frederick C. , Meschia Giacomo
Published: September 2009

In order to determine whether insulin stimulates glucose uptake by the hindlimb tissue of the fetal lamb, we performed 7 paired, euglycemic glucose ‘clamp’ experiments in 7 chronically prepared fetal sheep. Four sample sets for oxygen content, glucose and lactate concentration were drawn from the external iliac artery and vein during a control period and repeated during a euglycemic, hyperinsulinemic ‘clamp’ period. Insulin was infused at constant rate (4 mU/min/kg) and the fetal arterial glucose concentration was maintained by variable glucose infusion. The glucose/oxygen quotient increased significantly: 1.05 ± 0.07 (control) versus 2.02 ± 0.16 (hyperinsulinemia). There was no change in lactate/oxygen quotient. The data demonstrate that with maximal insulin stimulation, fetal hindlimb tissues increase glucose uptake by 92% with no large change in lactate production, indicating a net accumulation of glucose carbon under these experimental conditions.
Metabolic Quotients and Oxygen Extraction across the Uterus of the Post-Term Pregnant Rabbit under Chronic Steady-State Conditions
Authors: Jones R.O. , Murray R.D. , Meschia G. , Battaglia F.C.
Published: September 2009

The extraction of oxygen by the uterus in the term rabbit has been found to be very high. During post-term pregnancy, the fetuses of the rabbit are approximately 40% larger, despite a reduction in placental weight of approximately 30%. The purpose of our study was to investigate the changes that occur in the maternal rabbit to allow survival of the fetus under these conditions. Post-term pregnancies were induced in 5 white New Zealand rabbits by injections of chorionic gonadotropin and progesterone on the 26th day of gestation. Catheters were placed surgically on day 28, and blood samples were taken daily from the femoral artery and uterine veins starting at day 31. Each sample was analyzed for pH, PCO2, PO2, oxygen capacity and saturation, glucose, β-hydroxybutyrate, lactate and acetoacetate. Coefficients of extraction were calculated for oxygen and metabolic quotients were calculated for each substrate. These data are compared with those obtained for the term rabbit in previous studies. There was a significant increase in the coefficient of oxygen extraction in the post-term animals; however, the metabolic quotients across the uterus were not significantly different between the term and the post-term rabbit.
Contribution of Hepatic Fatty Acid Oxidation and Exogenous Galactose Supply to the Regulation of Glucose Homeostasis in the Newborn Rabbit
Authors: Pégorier J.P. , Duée P.H. , Girard J.R.
Published: September 2009

The inhibition of hepatic gluconeogenesis by 3-mercaptopicolinic acid (3-MPA) leads to a profound hypoglycemia in both suckling and fasting 24-hour-old rabbits. This hypoglycemia is totally reversed 1 h after the intragastric injection of an amount of galactose corresponding to the one ingested daily by the suckling newborns. This results from an active gluconeogenesis from galactose, which bypasses the site of inhibition by 3-MPA. However, this amount of galactose is not sufficient to maintain a normal blood glucose concentration for a long time, since 3 h after galactose injection, the blood glucose concentrations of newborn rabbits return to hypoglycemic values. When hepatic fatty acid oxidation is inhibited by 2-[6-(4-chlorophenoxy)hexyl]oxirane-2-carboxylate (POCA), 24-hour-old fasting rabbits become rapidly hypoglycemic secondary to a decrease in liver gluconeogenesis. The rate of hepatic gluconeogenesis is totally restored by giving medium-chain triglycerides, and the 24-hour-old rabbits become normoglycemic.
Characterization of Lipoprotein Lipase Activity in the Newborn Rat Liver
Authors: Reina Manuel , Vilaró Senén , Ramirez Ignasi , Llobera Miquel
Published: September 2009

Acetone ether powders of livers from starved newborn rats were applied to heparin-Sepharose affinity columns. The so-called hepatic triacylglycerol lipase was eluted with 0.9 M NaCl and a second lipolytic activity peak was eluted with 1.5 M NaCl. The behaviour of this 1.5 M NaCl-eluted fraction against increasing concentrations of serum, NaCl, protamine sulfate and heparin in the assay mixture was almost identical to that shown by partially purified lipoprotein lipase from adult rat adipose tissue, and clearly different from that shown by partially purified hepatic triacylglycerol lipase from the adult rat liver. We conclude that the newborn rat liver contains a lipoprotein lipase activity with similar properties to those found in adult adipose tissue lipoprotein lipase activity. It is suggested that this enzyme enables the neonatal liver to take up circulating triacylglycerols directly.
Lipid Metabolism in Pregnancy
Authors: Herrera E. , Gómez-Coronado D. , Lasunción M.A.
Published: September 2009

On the basis of bibliographic references and new own data, major adaptations of lipid metabolism occurring at late gestation are reviewed. Maternal hypertriglyceridemia at late gestation results from the juxtaposition of several factors: (1) enhanced adipose tissue lipolysis facilitating the availability to the liver of substrates for triglyceride synthesis and contributing to augmented flux of very low density lipoproteins (VLDL) into the circulation; (2) maternal hyperphagia and unmodified gut lipid absorption increasing chylomicron formation from dietary lipid; (3) reduced lipoprotein lipase (LPL) activity in extrahepatic tissues (especially adipose tissue) which does not allow a triglyceride removal proportional to their enhanced production. It is proposed that these changes are also responsible for the altered composition of VLDL in late pregnancy. In conditions of food deprivation the use of glycerol released from adipose tissue as preferential gluconeogenic substrate, and the enhanced maternal ketogenesis warrants the availability of fuels for the fetus. Just prior to parturition the increase in mammary gland LPL activity is responsible for the reduction in circulating triglycerides and prepares the mother for lactation.
Accelerated Starvation in Pregnancy: Implications for Dietary Treatment of Obesity and Gestational Diabetes mellitus
Authors: Metzger Boyd E. , Freinkel Norbert
Published: September 2009

The biological significance of ketonemia of brief duration and moderate proportions during pregnancy remains uncertain. Thus, controversy persists about whether caloric restriction for obese women during pregnancy, particularly when the obesity is complicated by gestational diabetes mellitus (GDM), constitutes appropriate therapy. We have demonstrated, in a rigorously controlled setting using a Clinical Research Center, that all of the features of ‘accelerated starvation’ become manifest after 14 h and before 18 h of dietary deprivation. Women with GDM exhibit the same capacity for early ‘accelerated starvation’ as in normal pregnancy; thus, their insulin deficiency and insulin resistance do not appear to be sufficient to render them increasedly at risk for uncontrolled catabolism. Some cautious exploration of the use of hypocaloric diets as a therapeutic approach to the metabolic disturbances of GDM may be justified.
Placental Transfer of Non-Esterified Fatty Acids in Normal and Diabetic Pregnancy
Authors: Thomas Chris R.
Published: September 2009

The placental transfer of non-esterified fatty acids, predominantly in the direction of mother to fetus, is regulated on a gross scale by the transplacental non-esterified fatty acid gradient. This is maintained by fetal liver lipid uptake and by enhanced lipolysis of circulating triacylglycerol in the pregnant mother. It is also dependent upon maternal placental blood flow, which is reduced in diabetes, upon the fetal umbilical blood flow, upon maternal and fetal albumin concentrations and upon intratrophoblastic fatty acid binding protein, which appears to be altered in diabetes. Circulating maternal tnacylglycerols also directly contribute non-esterified fatty acids to the fetus by intraplacental hydrolysis and the hypertriglyceridaemia associated with maternal diabetes, in concert with changes in lipase levels will enhance maternal to fetal lipid flux.
Placental Function in Maternal-Fetal Fat Transport in Diabetes
Authors: Shafrir Eleazar , Barash Varda
Published: September 2009

High levels of triglycerides (TG) and free fatty acids (FFA) in maternal plasma, in diabetes, promote fat passage to the fetus. In the streptozotocin-diabetic rat a significant correlation exists between maternal plasma and fetal tissue lipid contents, as shown by the accretion of labeled fatty acids or linoleate used as markers of maternal fat transfer. The passage of lipids through the placenta is not direct – this organ serves as an interim storage barrier with its lipid content increasing in proportion to the maternal TG and FFA level. Very low density lipoprotein (VLDL) TG are taken up with the aid of lipoprotein lipase as evident from TG = glycerol exchange when doubly labeled VLDL-TG are presented to the placenta. Esterification rate of albumin-bound FFA is considerably higher indicating that the rate of TG lipolysis is rate limiting and that the FFA are the main precursor of the placental lipids. The uptake of both FFA and VLDL-TG is associated with the retention of a substantial amount of FFA in the placenta. The size of the FFA pool corresponds to the size of the extracellular fluid space. The FFA cannot be eluted by repeated washing, suggesting that they are membrane bound. Placental slices with prelabeled TG gradually release FFA into the medium upon reincubation with FFA-free albumin, indicating that TG and FFA traverse the placenta in part by a sequential process of esterification and lipolysis and in part by diffusion as FFA. The latter are probably moving from the maternal to the fetal side within the interfacial capillary membrane lipids.
Measurement of Carbon Dioxide Production Rate in Sick Ventilated Premature Infants
Authors: Lucas A. , Nohria V. , Roberts S.B.
Published: September 2009

A new method is described for measuring the rate of carbon dioxide production, and hence for estimating energy expenditure, in preterm infants receiving assisted ventilation. In a validation study, the mean error in carbon dioxide measurement was 1.9%. Measurements were made, over a 45-min period, on 11 sick, ventilated subjects and carbon dioxide production rate was 5.2 ± 0.7 (SD) ml/min·kg body weight. We suggest that continuous monitoring of carbon dioxide output will contribute to the clinical assessment of the effects of different ventilator settings on pulmonary gas exchange and that estimated values for energy expenditure will be of value in nutritional studies on sick ventilated infants.
Elevated Levels of α2-Macroglobulin-Protease Complexes in Infants
Authors: Levine Jeremiah J. , Udall, Jr. John N. , Evernden Barbara A. , Epstein Michael F. , Bloch Kurt J.
Published: September 2009

Proteases form stable complexes with α2-macroglobin (α2-MG) in human plasma. We previously showed that the intestine of newborn rabbits takes up greater amounts of proteases than the intestine of weaned animals, and we suggested that the same phenomenon might occur in the human newborn. To test this possibility, α2-MG complexes were sought in plasma from 3-day-old human infants and adults. In addition, the level of α2-MG was measured. The concentration of α2-MG complexes and of α2-MG was significantly increased in the plasma of infants compared to adults. We suggest that the elevated levels of α2-MG complexes in infants may reflect the enhanced uptake of proteases from the intestine. In addition, there may also be decreased clearance of complexes by the mononuclear phagocytic system in infants. The elevated levels of α2-MG in the infant may reflect a response to the need for neutralizing proteases absorbed from the intestine.
Age-Related Development Profiles of the Antioxidative Defense System and the Peroxidative Status of the Pig Heart
Authors: Das Dipak K. , Flansaas Donna , Engelman Richard M. , Rousou John A. , Breyer Robert H. , Jones Randall , Lemeshow Stanley , Otani Hajime
Published: September 2009

The developmental profiles of the antioxidative defense system and the peroxidative status of the heart during growth and development were studied in pigs of three different age groups. A unique age-specific myocardial lipid peroxidation expressed in terms of malonaldehyde formation occurred after incubation of neonatal and adult pig heart homogenates in the absence of any added factors. Very little malonaldehyde release was noticed in the 0- to 2-day age group, while considerably higher activity was found in the 8- to 10-day-old animals. The 2-month-old pig heart again formed very little malonaldehyde. Myocardial injury from lipid peroxidation was highest in the 0- to 2-day age group, as evidenced by the release of oxidized glutathione, lactate dehydrogenase (LDH) and creatine kinase (CK) activities. Release of glutathione, LDH and CK decreased with age and was minimal in the adult group. The antioxidative enzymes, superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, increased during the first 10 days of neonatal growth and then levelled off. Glucose-6-phosphate dehydrogenase was present in appreciably lower amounts in adult hearts compared to neonatal hearts. Heart weight increased with aging, but myocardial water content decreased. Protein and DNA contents of hearts increased with age, such that the protein/DNA ratio almost doubled from the newborn to adult age. The results indicate that the newborn pig hearts are equipped with the antioxidative defense system, which undergoes significant development during the initial phase of neonatal growth and does not change appreciably thereafter. The results further suggest that the change in activity profile with aging is different for different enzymes, and the peroxidative status of the myocardium is not a function of these enzyme activities.
Protective Effect of Vitamin E against Lipoperoxides in Developing Rats
Authors: Yoshioka Tamotsu , Motoyama Hiroaki , Yamasaki Fumiyuki , Ando Masaaki , Yamasaki Madoka , Takehara Yoshiki
Published: September 2009

Pregnant rats were fed a vitamin E-supplemented diet, and blood and liver tissue concentrations of lipoperoxides were determined in fetuses and newborn rats. For comparison, a standard diet and a vitamin E-deficient diet were given to different animal groups. Fetal rats of all three groups showed very low blood and liver tissue levels of lipoperoxides, and there were no apparent intergroup differences. However, the levels increased sharply immediately after birth in the vitamin E-deficient rats, with the blood level being 4 times greater than in the other groups 10 days after birth, and the liver level 6 times greater than in the other groups 3 days after birth. Thus, vitamin E was revealed to be an important protective factor against abnormal synthesis and accumulation of lipoperoxides in liver tissues, particularly during the early stages after birth.
Lipogenesis in the Brown Adipose Tissue of the Fetal Baboon
Authors: Chakrabarty Krishna , Maeta Haruo , Vidyasagar Dharmapuri , Jeffay Henry , Manaligod Jose R.
Published: September 2009

The ultrastructure and lipogenic capacity of the white and brown adipose tissue (WAT and BAT) of 10 baboon fetuses (gestational age, 138–183 days) were studied. The axillary, interscapular and pericardiac sites had at least 50% brown fat cells while the retroorbital site contained white adipocytes only. Both WAT and BAT incorporated 3H2O and 14C-glycerol into lipids at similar high rates. The activities of enzyme acetyl CoA carboxylase and glycerokinase were higher than those reported in human BAT and comparable to these reported in rodent BAT under unstimulated conditions. It is concluded that in the fetal baboon adipose tissue is capable of considerable de novo lipogenesis and that, despite the differences in microscopic appearance, WAT and BAT have similar lipogenic potentials with respect to the parameters measured.
Plasma Amino Acids in Interrupted Aortic Arch and the Hypoplastic Left Heart Syndrome
Authors: Halliday Henry L. , Moore Raymond , O’Hara Denis
Published: September 2009

Plasma amino acids were measured in 8 babies with left-sided congenital heart disease, 3 interrupted aortic arch (IAA) and 5 hypoplastic left heart syndrome (HLH), at 1–6 days of age. There was an increase in total amino acid levels when compared with 40 control infants of similar gestational age and birth weight. Both branched-chain and aromatic amino acids were raised although there were differences between the babies with IAA and HLH. Babies with HLH had higher total amino acid levels than babies with IAA, the difference being due to raised branched-chain amino acids. Apart from the anatomical differences babies with HLH had metabolic acidosis at the time of sampling whereas babies with IAA had normal pH. It is possible that the increase in amino acid levels in babies with obstructed left-sided congenital heart disease is due to hepatic congestion and hypoperfusion, although altered acid base states may also be important.
Fetal Arginine Vasopressin under Basal and Hypoosmolal Conditions
Authors: Leake Rosemary D. , Ervin Gore , Ross Michael G. , Stegner Hendrik , Fisher Delbert A.
Published: September 2009

Blood samples (4 ml) for plasma arginine vasopressin (AVP) measurements were obtained at 3- to 4-hour intervals under basal conditions for 1–2 days from 5 date-bred ewes with chronic maternal and fetal vascular catheters. In addition, 6 chronically catheterized ewes were infused with 2 liters of 0.45% NaCl over 30 min. Fetal and maternal blood samples were obtained before and after the infusion period for measurement of plasma osmolality and AVP concentrations. In the first study, maternal and fetal plasma AVP levels correlated significantly (p < 0.01, by linear regression analysis) under basal conditions. In the second study, baseline mean ( ± SEM) plasma osmolality was similar for pregnant ewes and fetuses (303 ± 3.1 and 302 ± 2.4 mosm/kg, respectively). There was a significant (each, p < 0.01 by paired t test) decrease from baseline in maternal and fetal osmolality during the 30 min after completion of the hypotonic saline (to 292 ± 4.7 and 296 ± 2.4 mosm/kg, respectively). Fetal plasma AVP levels decreased 17 ± 6% by 30 min following the completion of water loading (1.7 ± 0.07 to 1.4 ± 0.16 μU/ml; p < 0.05). Maternal plasma AVP levels decreased 16 ± 4% by 30 min after completion of infusion (1.6 ± 0.14 to 1.38 ± 0.6 μU/ml; p < 0.05). These results indicate that maternal and fetal plasma AVP levels correlate under basal conditions and that maternal water loading, which significantly decreases fetal plasma osmolality, significantly suppresses fetal plasma AVP concentrations.
Fetal Beta-Endorphin Levels in Response to Reductions in Uterine Blood Flow
Authors: Skillman Carmela A. , Clark Kenneth E.
Published: September 2009

Fetal β-endorphin release has been associated with fetal hypoxia. The purpose of this study was to assess the degree of uterine blood flow reduction needed to elicit fetal β-endorphin release in the sheep since there is a large reserve of oxygen supply to the fetus. Uterine blood flow was reduced by 26 ± 2, 46 ± 3 and 66 ± 2%, producing fetal oxygen content concentrations of 5.7 ± 0.6, 4.4 ± 0.7 and 2.6 ± 0.3 ml/dl, respectively. Although fetal oxygen concentrations were significantly decreased in the groups with a reduction in uterine blood flow of 46 and 66%, β-endorphin was elevated only in the latter group. It is speculated that fetal β-endorphin is released at a level of hypoxia which leads to a decrease in fetal oxygen consumption. A reduction in uterine blood flow of 66% appears to produce a stressful environment for the fetus as measured by fetal plasma β-endorphin levels.
Effect of Guanidinoethyl Sulfonate on Taurine Concentrations and Fetal Growth in Pregnant Rats
Authors: Ejiri K. , Akahori S. , Kudo K. , Sekiba K. , Ubuka T.
Published: September 2009

Guanidinoethyl sulfonate (GES), a transport antagonist of taurine, was given to pregnant rats from day 11 to 21 of gestation as a 1 % solution in drinking water. On day 21 of gestation in GES-treated pregnant rats, the concentration of taurine markedly decreased in the fetal whole body (54% of the control), the fetal liver (37%), the fetal whole brain (87%), the placenta (32%), the maternal liver (33%), the maternal whole brain (32%), and the maternal plasma (46 %). The wet weight of fetal whole body, liver and brain of fetus, and placenta also showed a significant drop. But there were no differences of weight gain, in the liver and brain weights of the mother of the control and GES-treated pregnant rats. The urinary excretion of taurine in pregnant rats treated with GES was much higher than that of the controls. These results suggest that the administration of GES to pregnant rats induces much urinary taurine excretion with a resulting decrease in the tissue taurine content and readily produces taurine-deficient fetal rats.