bluuebunny/crossref_metadata_2025 huggingface dataset:
Technique for in situ Perfusion of the Guinea Pig Placenta
Authors: Fenton Enid
Published: September 2009

A simple technique is described for perfusing the guinea pig placenta in situ through the umbilical circulation. Flow rates, perfusion pressures, and transplacental electrical potential gradients were maintained for the duration of the perfusions (1–2 h) at values reported for the exteriorised fetus. Terminally, the placentae were shown to be uniformly perfused and of normal weight.
Development of Perirenal Adipose Tissue in the Neonatal Lamb: Effects of Dietary Safflower Oil
Authors: Vernon R.G.
Published: September 2009

Perirenal adipose tissue development was investigated in lambs from birth until 17 days of age. Changes in the morphology, the lipid, protein, RNA and DNA content, the adipocyte number and size, and the rate of protein, RNA and DNA synthesis of the perirenal fat-pads are reported. During the first 9 days after birth the tissue lost the morphological characteristics of brown adipose tissue and acquired those of white adipose tissue. As there was no change in either the number of adipocytes or the DNA content of the fat-pads between birth and 9 days of age it is concluded that there was a differentiation of brown into white adipocytes. Over 80% of the increase in tissue weight between birth and 17 days of age was due to lipid deposition. Administration of safflower oil to the lambs had no apparent effect on the change from brown to white fat, but it markedly reduced the rate of lipid deposition between days 9 and 17 post partum.
Symptomatic Neonatal Plethora
Authors: Saigal S. , Usher R.H.
Published: September 2009

Blood volume and clinical data are reported on 8 premature and 3 full-term infants who presented with symptoms apparently due to polycythemia or hypervolemia. These cases termed ‘symptomatic neonatal plethora’ were caused by large placental transfusions associated with delayed clamping of the umbilical cord. Tachypnea, mild cyanosis, plethoric skin color, and neurological depression persisted on average for 30 h after birth. Chest X-rays showed mild cardiomegaly, pulmonary congestion and edema, and pleural effusions. Although the course was in general benign, phlebotomy was considered to be indicated in three infants to treat progressive clinical deterioration. The symptomatology and blood volume on these infants were compared with infants in an ongoing study with controlled time of cord clamping. Neonatal plethora must be considered as one cause of Ê»transient tachypnea of the newborn’.
Comparison of Postnatal Development of Several Acid Glycosidases in the Rat Forebrain and Cerebellum
Authors: Lau Herbert C. , Horowitz Carolyn , Jumawan Jocelyn , Koldovsky Otakar
Published: September 2009

Changes of activity of several glycosidases (β-galactosidase, (β-glucuronidase, N-acetyl-β-D-glucosaminidase, α-D-mannosidase and α-L-fucosidase) were compared in the forebrain and cerebellum during postnatal development of the rat. Detailed analysis of the data showed similarities, but also substantial differences in their development in both organs. This is interpreted as an indication of the presence of common regulatory mechanisms, as well as of other factors which differently influence development of the glycosidases studied in both CNS parts.
Hyperglycemia and Glycogen Storage in the Rabbit Fetal Liver
Authors: Gilbert M. , Jost A.
Published: September 2009

A 2-hour glucose infusion to pregnant rabbits resulted in fetal hyperglycemia. The question was studied whether this hyperglycemia would induce an increase in the concentration of glycogen in the fetal liver. The result depended upon the age of the fetus. In 24- or 25-day-old fetuses hyperglycemia did not increase the liver glycogen. On the contrary, on day 26, 27 and 28, the glycogen content in the liver was approximately twice as high as in controls. However, in fetuses which were decapitated on day 24 and studied on day 26, the maternal glucose infusion did not increase the glycogen stores. But in those fetuses decapitated on day 25 hyperglycemia provoked glycogen deposition. The activity of liver glycogen synthetase (active form a and total form a + b) increased between days 24 and 28 in control fetuses. Some increase of the a form already occurs between days 24 and 25. In fetuses decapitated on day 23, the a form was found almost as low on day 31 as it was on day 23. The incapacity of the liver of fetuses under 26 days of age or of those decapitated before day 25 to store glycogen under conditions of hyperglycemia probably results from a low glycogen synthetase activity.
Caffeine Pharmacokinetics in Young and Adult Dogs
Authors: Warszawski Ditsa , Gorodischer Rafael , Moses Shimon W. , Bark Hylton
Published: September 2009

The pharmacokinetics of caffeine were studied in young (age: 1 day, 7 days, 14 days, 30–45 days) and adult dogs following a single intravenous dose of 50 mg/kg. Mean ( ± SE) plasma elimination half life (T½ was 47.5 ( ± 5.35) h in 1-day-old puppies, as opposed to 6.66 ( ± 0.85) h in adult dogs. A rapid decrease in plasma T½ values occurred during the first 2 weeks of life. At about 14 days of age caffeine plasma T½ was similar to that of adults. The volume of distribution was greatest (0.94 ± 0.03 liters/kg) and the total body clearance was smallest (2.81 ± 0.73 liters/kg/min × 10––4) in the 1-day-old animals. The much smaller body clearance of caffeine in the newborn as compared to the adult dog could be due to a lower rate of metabolism and/or renal excretion of this drug in the young.
Effect of Irradiation on the Erythrocyte Membranes of Homozygous Gunn Rat Sucklings
Authors: Sato Hiroshi , Katoh-Semba Ritsuko , Kashiwamata Shigeo
Published: September 2009

Erythrocyte membranes were isolated from irradiated Gunn’s strain of jaundiced rat sucklings, and photodynamic action of bilirubin in vivo was investigated using sodium dodecyl sulfate polyacrylamide-gel electrophoresis. The effectiveness of irradiation was verified in terms of decrease of plasma bilirubin concentrations and cerebellar bilirubin contents, and also by recovery from the cerebellar hypoplasia, a characteristic feature of the homozygotes (j/j). The cross-linking of erythrocyte membrane proteins by photodynamic action of bilirubin was demonstrated in vitro in rat erythrocytes as reported for human erythrocytes by Girotti (Biochemistry 14: 3311 1975). The phenomenon, however, was not observed in vivo. Instead, a protein band with a mol. wt. of 32,000 was increased by the irradiation both in the homozygous (j/j) and heterozygous (j/+) Gunn rats.
Cardiac Myopathies in Neonatal Lambs: Histological and Histochemical Studies
Authors: Cheema Ashiq H. , Gilani Shamshad H.
Published: September 2009

White muscle disease (WMD), a selenium-responsive cardiac myopathy in neonatal lambs has been described from southern Iran. 15 lambs in terminal condition were referred to our lab. All the lambs were observed with the affected hearts. The lambs examined were between the postnatal ages of 1 week and 3 months. Gross changes included chalky-white appearance of entire endocardium of right ventricle and subendocardial plaques in the interventricular septum and left ventricular wall. Histologically the affected myofibrils showed swelling, acidophilia, fragmentation, segmental and patchy myonecrosis, round muscle cell nuclei, loss of sarcoplasm and sarcolemmal collapse. Purkinje fibers were relatively unaffected. Histochemical studies including Von Kossa and other stains indicated marked deposition of calcium salts in the cytoplasm of the damaged myofibrils. Calcium salts appeared as uniform, fine granules in relation to individual fiber striations. It appears that rapid accumulation of calcium into the damaged cells possibly interferes with the mitochondrial activity. As mitochondria bind excessive calcium, their capacity to respire and phosphorylate is depressed thus causing myocardial necrosis. The cardiac myopathy noted in our investigation is probably due to selenium deficiency in the soil of southern Iran. When selenium was given, it resulted in the fast recovery of the affected neonatal lambs. Moreover, no further cases of this disease (WMD) were reported after such treatments.
Balance of Net Base in the Rat
Authors: Wamberg S. , Hansen A.C. , Engel K. , Kildeberg P.
Published: September 2009

Mineral and net base balances were studied in groups of male weanling Wistar rats given oral loads of calcium chloride, monocalcium phosphate plus monosodium phosphate, and disodium phosphate plus monopotassium phosphate, respectively. A group of adult nongrowing rats loaded with calcium chloride was included for comparison. In response to CaCl2 loading, gastrointestinal net base absorption was inhibited due, largely, to luminal precipitation of tertiary phosphates of calcium and magnesium. In the weanling animal, however, a rise in the rate of renal net acid excretion matched the concomitant decrement in the rate of net base absorption, permitting of continued skeletal net base storage. Similarly, in the adult animals augmented renal net acid excretion offset a positive rate of gastrointestinal net acid absorption with a resultant (normal) zero net base balance. Loading with monocalcium phosphate and disodium phosphate at a constant oral net base intake did not influence the overall net base balance, but disodium phosphate loading caused significant sodium retention.
Prematurity and Perinatal Mortality in the Rhesus (Macaca mulatta): Relationship to Birth Weight and Gestational Age
Authors: Shaughnessy Peter W. , DiGiacomo Ronald F. , Martin David P. , Valerio David A.
Published: September 2009

While the relative influence of birth weight and gestational age in determining perinatal mortality has not been definitively established, it has been assumed that birth weight makes the predominant contribution to perinatal mortality. The joint effects of birth weight and gestational age were examined by analyzing approximately 2,500 births from timed pregnancies in two rhesus (Macaca mulatta) breeding colonies. Perinatal events in the rhesus are described and shown to be similar to the human. The results demonstrate that gestational age is as important as birth weight in determining perinatal mortality. Since the degree of accuracy in the estimation of rhesus gestational age was much greater than is usually attained in human studies, the estimation of gestational age from the last menses may be too crude to determine the importance of this variable in human perinatal mortality.
Source of Fetal-Stored Lipids during Maternal Starvation in Rabbits
Authors: Elphick M.C. , Edson J.L. , Lawlor J.P. , Hull D.
Published: September 2009

The effect of 48 h maternal starvation on the composition of fetal rabbit brown and white adipose tissue was examined. Compared with fed control rabbits, adipose tissue triglyceride fatty acids took on a composition more like that of maternal plasma free fatty acids (FFA), whose concentration more than doubled after 48 h starvation. It is concluded that maternal FFA contribution to the fetal lipids increases during starvation and certain fetal fatty acids, in particular linoleic acid, may in the fed state be derived from maternal lipids other than the FFA.
Is There a Blood-Brain Relationship for Saturated Fatty Acids during Development?
Authors: Bourre Jean-Marie , Gozlan-Devillierre Nicole , Daudu Odile , Baumann Nicole
Published: September 2009

Transport of subcutaneously injected [1-14C]-stearic acid through the blood-brain barrier is compared with endogenous biosynthesis (within the brain) during postnatal brain development in mice. The uptake is very important during glial cell multiplication and myelination; endogenous microsomal synthesis is most active during myelination, soluble de novo mechanism is prominent during cell multiplication (mitochondrial systems are not directly related to these events). A parallel is drawn between myelin fatty acids, microsomal synthesis and uptake from the blood.
Isozyme Profiles of Lactic Dehydrogenase and Creatine Phosphokinase in Neonatal Mouse Hearts
Authors: Courtney K.D. , Ebron M.T.
Published: September 2009

Isozyme profiles of lactic dehydrogenase (LDH) and creatine phosphokinase (CPK) were determined in cardiac tissue of mice during postnatal development. LDH isozymes 1 and 5 showed a definite developmental change, achieving the adult values by 20 days of age, while the other three isozymes showed no change. During the first 2 postnatal weeks, a developmental change was seen in the activities of the ‘mito’ and MB isozymes of CPK, with the adult profile being established by day 20. CPK isozymes MM and BB did not change during this interval.
Correlation of DNA Accumulation Rate with Thymidylate Synthetase Activity in Developing Rat Cerebellum: Effect of Hypothyroidism
Authors: Clark B.R. , Weichsel jr. M.E. , Poland R.E.
Published: September 2009

Experimental hypothyroidism in the neonatal rat is known to result in a delay in cerebellar DNA biosynthesis. Because of the known high correlation between rate of DNA biosynthesis and thymidylate synthetase (TS) activity in neonatal hyperthyroidism in the rat, we studied this correlation under conditions of neonatal hypothyroidism. The equation for the least-squares logistic curve describing cerebellar DNA content in neonatal rats as a function of postnatal age (day of birth is day 0), was differentiated to give an expression for the instantaneous rate of cerebellar DNA accumulation in units of nanograms per hour per milligram wet cerebellum. The rate of accumulation of cerebellar DNA in hypothyroid neonatal rats from litters of propylthiouracil-treated dams was significantly (p < 0.05) decreased below control values at 3, 5, and 9 days of age, and significantly elevated at 15 and 21 days of age; the maximum decrease (78% of control) occurred on day 5, and the maximum elevation (266% of control) occurred on day 21. The developmental pattern of cerebellar TS activity in units of picomoles per hour per milligram wet cerebellum, closely paralleled the pattern for DNA accumulation rate in cerebella of both normal and hypothyroid neonatal rats, with cerebellar TS activity in hypothyroid pups significantly decreased below normal on postnatal days, 5 and 9, and significantly elevated on days 15 and 21. During this early developmental time period, a linear correlation of the rates of cerebellar DNA accumulation with the values of cerebellar TS activity gave correlation coefficients of 0.98 and 0.95 for normal and hypothyroid animals, respectively. These data thus support results from our previous study of thyroxine-induced hyperthyroidism, further suggesting that TS may be critical for maintenance of replicative DNA synthesis in the developing rat cerebellum.
Studies in Meconium in Cystic Fibrosis: the Activities of alpha-D-Mannosidase, beta-Glucuronidase, beta-D-Fucosidase Acid and Alkaline Phosphatase
Authors: Antonowicz I. , Ishida S. , Shwachman H.
Published: September 2009

The specific activities of α-D-mannosidase, β-glucuronidase, β-D-fucosidase, acid and alkaline phosphatases were studied in meconium from infants with cystic fibrosis (CF) and control subjects. The study revealed significant variations in the specific activity of the enzymes except for acid phosphatase. The variations were not uniform. The activities of α-D-mannosidase, β-glucuron-idase and alkaline phosphatase were markedly decreased (p < 0.001, p < 0.002, p < 0.001, respectively), while the activity of β-D-fucosidase was significantly increased (p < 0.001) in meconium from the infants with CF. It is suggested that the decreased activity of α-D-mannosidase and β-glucuronidase might contribute to the accumulation of the abnormal substances in CF meconium. The highly increased activity of β-D-fucosidase raises the possibility of an additional or alternative method for screening newborns for CF using meconium as the test material.
Maintenance of Central and Peripheral Monoamine Oxidase Activity in Developing Rats Subjected to Disturbed Alimentary Rhythms and Undernutrition
Authors: Parvez H. , Ismahan G. , Parvez S.
Published: September 2009

Monoamine oxidase (MAO) activity was studied in whole brain, hypothalamus, adrenals and liver of developing rats subjected to disturbed feeding patterns or undernutrition for 3 weeks. The rats were divided into six groups: (1) normally fed controls; (2) rats starved for 24 h, fed for the following 8 h and killed after the last starvation period (PAS); (3) same treatment as in (2) but killed after the last feeding period (PAF); (4) rats starved for 16 h, fed for the following 8 h at a constant schedule, and killed after the last starvation period (PS); (5) same treatment as in (4) but killed after the last feeding period (PF), and (6) undernourished (U). Alteration of the feeding time resulted in significant decreases of MAO activity in the brain and the adrenal gland whereas the hypothalamus and the liver showed a slight increase in activity in the PAS group. In PS rats, MAO activity increased in the brain, adrenals and hypothalamus; in PF rats, the effects of the treatment were inverse. Both in the PS and PF rats, hepatic MAO activity was strongly decreased when assayed with kynuramine. In U rats, hepatic MAO activity was highly increased when assayed with kynuramine but the other tissues responded differently. The adrenaline and noradrenaline stocks of the adrenal gland were markedly increased in all the treated groups; the maximum increase in noradrenaline was observed in the PS rats. The results suggest that any disturbance in the feeding pattern affects the MAO activity in the central and peripheral regions of the young rat during postnatal development. The developing rat seems to get accustomed to new alimentary rhythms, and normal monoaminergic function is rapidly restored when the rat is given a compensatory diet. Increased adrenal catecholamines after a disturbance in the feeding patterns seem to be a response to stress.
Immunochemical Characterization of Mature and Immature Glomerular Basement Membrane
Authors: Lubec Gert , Coradello Hermann
Published: September 2009

20 kidneys from premature infants (27th to 38th weeks of gestation), 5 kidneys of mature newborns and 5 kidneys of children between 5 and 15 years of age were obtained at necropsy and glomerular basement membranes (GBM) isolated. The isolated GBMs were degraded by papain and the degradation products were characterized by immunoelectrophoresis applying an antihuman GBM antiserum from the rabbit. GBMs of children between 5 and 15 years showed in each case 3 precipitation lines distributed from the α-γ-zone. The examined newborns and 17 premature infants presented two precipitation lines only, moving with α1-mobility and β-γ-inter-region. 3 premature infants showed a pattern with 24 different precipitation lines of different mobility, maybe interpretable as a result of bacterial digestion. On the grounds of these findings we postulate that the GBM is, from an immunochemical point of view, immature at birth and in the late fetal life becoming mature in the child with about 5.
Developmental Pattern of Pulmonary Lipoprotein Lipase in Growing Rats
Authors: Hietanen Eino , Hartiala Jaakko
Published: September 2009

The developmental pattern of pulmonary lipoprotein lipase (LPL) activity was measured in growing male and female rats from the neonatal period to the adult age. The pulmonary phospholipid content showed a sharp increase at term from premature low level. At the same time the LPL activity increased markedly showing thereafter a decrease at 1 week of age and increasing thereafter to the adult age. Also the phospholipid content was low at 1 week of age. Thus the pulmonary phospholipid content and LPL activity change in the same way during the development indicating possibly that the LPL by supplying free fatty acids for the phospholipid biosynthesis may be one of the rate-limiting enzymes in the pulmonary surfactant synthesis.
Pulmonary Aeration after Unilateral Fetal Ligation of Pulmonary Artery in Neonatal Rabbits
Authors: Thomasson Björn , Kero Pentti , Länsimies Esko , Toikkanen Sakari , Välimäki Ilkka
Published: September 2009

When the pulmonary artery was ligated at the gestational age of 30 days, 9 out of the 17 rabbit fetuses had vital lungs and in 7 of these the lungs were aerated after breathing for 15 min to 1 h. Ligation before this gestational age caused necrotic lungs in all 13 rabbit fetuses. On the basis of this we can conclude that the bronchial circulation is not sufficient to ensure vitality of the fetal lung and the pulmonary circulation does not play a major role in the primary aeration of the lungs at birth.
On the Mechanism of Renal Sodium Handling in Newborn Infants
Authors: Sulyok E. , Varga F. , Györy E. , Jobst K. , Csaba I.F.
Published: September 2009

In an attempt to delineate the specific tubular defect in sodium reabsorption in low-birth-weight neonates, fractional sodium excretion (CNa/Ccr), distal tubular sodium delivery (CNa+CH2O), and distal tubular sodium reabsorption [(CH2O/CH2O+CNa) × 100] were determined in 8 healthy premature and 10 full-term newborn infants. The mean birth weight was 1,701 g (range: 1,240–2,120 g) and the mean gestational age was 32.6 weeks (range: 28–35 weeks) for premature; and 3,199 g (range: 2,670–3,670 g) and 38.9 weeks (range: 38–41 weeks) for full-term neonates. It was demonstrated that the significantly higher fractional sodium excretion in premature infants (1.44 ± 0.33 SE versus 0.36 ± 0.09%, p < 0.01) resulted from significantly decreased proximal (CNa+CH2O: 0.674 ± 0.105 versus 0.360 ± 0.069 ml/min/1.73 m2, p < 0.05) and distal [(CH2O/CH2O+CNa) × 100:69.9 ± 3.3 versus 85.8 ± 3.4%, p < 0.01] tubular sodium reabsorption.
Role of Glucocorticosteroid Hormones on the Levels of Rat Liver Carbamoylphosphate Synthase (Ammonia) and Arginase Activity during Ontogenesis
Authors: Lamers W.H. , Mooren P.G.
Published: September 2009

In rats, hepatic carbamoylphosphate synthase (ammonia) and arginase activities are closely related during development. Activities increase sharply during the last 4 prenatal and first 4 postnatal days and during the 3rd postnatal week. Decreases are observed between 4 and 9 days after birth, and after weaning, during adolescence. During senescence activities increase again. Before birth, treatment with prednisolone is far less effective in increasing enzyme activities than during the first 2 postnatal weeks, when it seems to precipitate normal development of the 3rd postnatal week. In the 4th postnatal week the sensitivity to prednisolone treatment increases approximately 25-fold. During the 2nd postnatal week, dexamethasone proves to be more potent, on a molar base, than triamcinolone which is more potent than prednisolone and hydrocortisone. Increases in enzyme activities which are associated with increases in blood levels of glucocorticosteroids are also associated with 2- to 3-fold decreases in DNA content, i.e. with decreases in hepatocyte multiplication rate and increases in hepatocyte cell size. These phenomena may be sequelae of quantal cell cycles leading to changes in hormone response capacity or hormone response sensitivity.
Developmental Changes in Brain TRH and in Plasma and Pituitary TSH and Prolactin Levels in the Rat
Authors: Oliver C. , Eskay R.L. , Porter J.C.
Published: September 2009

TRH in the hypothalamus and the rest of the brain, as well as TSH and prolactin in the pituitary gland and the plasma have been determined by radioimmunoassay in rats varying in age (10- to 22-day-old fetuses and 1- to 60-day-old rats). TRH is first detected on the 16th day of gestation and its maximum increase occurs during the first 3 weeks of life both in the hypothalamus and the rest of the brain. The evolution patterns of TSH and prolactin in the plasma and the pituitary gland are discussed in relation to TRH levels in the brain and in the hypothalamus.
Postnatal Changes in Urinary Prostaglandin E Excretion in Premature Infants
Authors: Sulyok E. , Ertl T. , Csaba I.F. , Varga F.
Published: September 2009

Urinary PGE excretion was measured by radioimmunoassay in a group of 11 healthy premature infants with a mean birth weight of 1,502 g (range 1,050–1,950 g) and a mean gestational age of 31.6 weeks (range 29–33 weeks), respectively. Measurements were made on the 7th day of life and at weekly intervals thereafter until the 5th week of life. It was demonstrated that urinary PGE excretion significantly increased from the very low level of 6.23 ± 0.70 ng/24 h (mean ± SE) on the 7th day to a value of 17.99 ± 3.53 ng/24 h by the end of the 3rd week (p < 0.005). Later on it remained practically unchanged. It is suggested that its rapid increase during the first 3 weeks of life may be the result of the highly elevated activity of the renin-angiotensin-aldosterone system and it may play a role in controlling renal blood flow.
Studies on the Formation of Phosphoenolpyruvate and Citric Acid Cycle Intermediates by Neonatal Piglet Liver Mitochondria
Authors: Bieber L.L. , Helmrath T. , Dolanski E.A. , Belanger L.L. , Choi Y.R.
Published: September 2009

The capacity of mitochondria isolated from livers of 5-day-old piglets to convert pyruvate to phosphoenolpyruvate, malate and citrate has been investigated. These mochondria have a large capacity to flux pyruvate through the pyruvate carboxyiase reaction causing an accumulation of malate, citrate and phosphoenolpyruvate. As much as 70% of the pyruvate utilized during state 3 respiration can flux through the pymvate carboxyiase reaction. The data indicate that phosphoenolpyruvate from mitochondria can contribute a significant fraction of the carbon skeletons of pyruvate converted to glucose by piglet liver (estimated to be 30%).
Prematurity in the Rat
Authors: Cuezva J.M. , Benito M. , Moreno F.J. , Medina J.M.
Published: September 2009

The time-courses of liver glycogen, plasma glucose, lactate, alanine and glycerol concentrations in term and preterm rats undergoing hypothermia (30 °C) during the first 2 h after delivery have been studied. Hypothermia prevented liver glycogenolysis and the neonatal decrease of plasma glucose concentration in term and preterm rats during the first 2 h after delivery. Hypothermia decreased plasma glucose, lactate and alanine utilization but increased plasma glycerol concentration. These results suggest that hypothermia blunts the utilization of the main metabolic substrates but increases brown adipose tissue lipolysis for thermogenesis.
Role of Thyroid Hormones in the Normal and Glucocorticosteroid Hormone-Induced Evolution of Carbamoylphosphate Synthase (Ammonia) and Arginase Activity in Perinatal Rat Liver
Authors: Lamers W.H. , Mooren P.G.
Published: September 2009

Administration of thyroid hormones causes a dose-dependent increase in carbamoylphosphate synthase (ammonia) and arginase activities in fetal rat liver but not in neonatal rat liver. Simultaneous administration of thyroid and glucocorticosteroid hormones enhances enzyme accumulation still further in the fetus. When administered before birth, the relative potencies of T4 and reverse T3, compared to T3 are 20–25% and 1–2%, respectively. Both before and after birth, thyroid hormones enhance DNA content of the liver. Hypophysectomy of rat fetus reduces the carbamoylphosphate synthase activity level in hepatocytes to 30–40% of that in intact animals. Thyroid and glucocorticosteroid hormone administered individually to hypophysectomized animals stimulate enzyme activity 2- to 3-fold; and if administered simultaneously, 4- to 6-fold. Premature delivery with continuation of thyroid and/or glucocorticosteroid hormone treatment started before birth shows uninterrupted enzyme accumulation profiles. Delaying birth by progesterone treatment of the dam leads to uninterrupted but reduced rates of enzyme accumulation in hepatocytes.
Serum and Urine Concentrations of Protein, Urea, Sodium, and Potassium during the Immediate Postnatal Period of the Suckling Pig
Authors: Parker R.O. , Aherne F.X.
Published: September 2009

Serum and urine concentrations of protein, urea, Na and K were monitored between birth and 72 h in neonatal pigs. Serum protein increased (p < 0.05) 37 mg/ml after suckling, while urinary protein temporarily increased (p < 0.05) to 14.7 ± 0.98 mg/ml by 12 h but declined (p < 0.05) to birth values by 72 h. Urinary urea levels tripled (p < 0.05) by 12 h and remained elevated. The ratio of urea in the urine to that in the serum ranged from 17 to 29. Serum Na concentrations were stable (141–146 mEq/l) during the 72 h, and urinary Na levels were low (9–44 mEq/l) and decreased (p < 0.05) by 72 h. Serum K fluctuated and was highest (p < 0.05) at birth (6.4 ± 0.26 mEq/l) and lowest by 72 h (4.4 ± 0.26 mEq/l). Levels of K excreted in the urine were high (20.0–7.6 mEq/l) compared to blood levels. Colostral concentrations of Na were low (81–73 ± 3.8 mEq/l) while K levels were high (24.3–28.8 ± 1.39 mEq/l) compared to piglet serum levels.
Effects of Apomorphine on Ventilation in the Neonate Rat
Authors: Farber J.P. , Phillips M.I.
Published: September 2009

Systemic administration of apomorphine (APO) to anesthetized adult rats can influence breathing pattern, and several studies suggest that dopaminergic pathways are involved. To evaluate whether ventilatory responses to APO were already present in the neonate rat, animals between 3 and 9 days of age, with sectioned vagal and sympathetic trunks, were tested. Results showed that subcutaneously administered APO (1 mg/kg) decreased breathing frequency and increased tidal volume. In addition, an instability in inspiratory off-switching was sometimes obtained. Effects on breathing with APO were antagonized by the dopaminergic blocking agent, haloperidol (2 mg/kg). Except for changes in inspiratory off-switching, these results in neonate rats are qualitatively comparable to effects obtained with APO in similarly prepared adult animals.
An Estimate of the Caloric Requirements of the Human Fetus
Authors: Sparks John W. , Girard Jean R. , Battaglia Frederick C.
Published: September 2009

The caloric requirements of the human fetus have been calculated from the reported values of the fetal oxygen consumption and the composition of the new tissue deposited, both expressed as their caloric equivalents. It is estimated that the deposition of fat represents over half the caloric accretion from the 27th week of gestation until term, and ∼90% of the caloric accretion at term. The total caloric requirement of the human fetus at term is estimated at ∼90–100 kcal/kg/day.
Serum Enzymes and Bilirubin in Neonates after Normal or Complicated Delivery
Authors: Parmar C.R. , Sareen K.N.
Published: September 2009

318 newborn babies were studied at term and after various complications of pregnancy or delivery for serum total bilirubin, alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and glucose-6-phosphate dehydrogenase (G-6-PD). The total bilirubin levels tended to be lower in infants born after various complications of pregnancy or delivery than at term. The mean activity of ALP in the infants was not different from that of normal adults. Its activity decreased by the 5th day of life and was lower in the fetal distress group. The AST activity was much wider than the adult range but ALT activity did not differ from the adult level.
Lipid Peroxidation and Antioxidants in the Rat Lung during Development
Authors: Yoshioka Tamotsu , Shimada Toshie , Sekiba Kaoru
Published: September 2009

The extent of lipid peroxidation and the levels of its antioxidants such as superoxide dismutase (SOD), catalase and glutathione peroxidase (GSH-Px) were determined on lung tissues of the fetal, newborn and adult rat. Lipid peroxide formation was slight in the fetal period but augmented after birth reaching a peak at about 10 days after birth. The peroxide concentration then gradually declined with development and the adult level was found comparable to the fetal level. In the examination of the developmental defensive mechanism on the basis of assays for the aforementioned antioxidant enzymes in lung tissue, the SOD activity was low in fetuses reaching approximately 90% of the adult level at 10 days of life. Catalase was extremely low in concentration at all times, and age-related variations could not be definitely obtained. GSH-Px was also measured low in the fetal period and during 20 days after birth, but a subsequent gradual rise resulted in threefold greater activity in adults than in fetuses.
The Effect of Exogenous Steroids and Steroid Inhibitors on IgG Transmission in Young Rats
Authors: Morris B. , Morris R.
Published: September 2009

The transmission of labelled IgG by the proximal small intestine was assessed in 16- and 18-day-old rats. Closure had commenced by 18 days and in some animals was well advanced by this age. The injection of large doses of cortisone acetate, hydrocortisone sodium succinate, deoxycorticosterone acetate and corticosterone induced precocious closure of the small intestine by 16 days; and all but the latter steroid also induced precocious cell replacement in the ileum. Maternal deprivation for about 18 h daily led to closure of the proximal small intestine but did not induce precocious replacement in the ileum. The injection of metopirone, aminoglutethimide and ACTH resulted in partial closure of the proximal small intestine but did not induce precocious cell replacement in the ileum. Maternal deprivation for about 8 h daily produced a similar result.
Circadian Rhythms in Neonatal Rat Parotid Gland Acinar Cell and Ileal Crypt Cell Mitosis
Authors: Klein R.M. , Whitney S.L.
Published: September 2009

Mitotic activity of parotid gland acinar cells and ileal crypt cells was analyzed over the course of a 26-hour period at 8 and 15 days after birth. At 8 days there is no detectable circadian rhythm of mitosis in either tissue while at 15 days after birth there is a mitotic rhythm with an amplitude of 36.8% in ileum and 26.5% in parotid gland. Possible factors which may influence and initiate circadian rhythms are discussed.
Cortisone and Cortisol in Maternal and Fetal Blood and in Amniotic Fluid during the Final Ten Days of Gestation in the Rabbit
Authors: Barr Heather A. , Lugg Moira A. , Nicholas Terence E.
Published: September 2009

We have used instant thin-layer chromatography and radioimmunoassay to measure the concentrations of total cortisone (E) and cortisol (F) in the fetal and maternal compartments of the rabbit. The concentration of F in fetal blood increased markedly at day 25; this is just prior to the rapid increase in the surfactant phospholipids in lung tissue in this species. This increase coincided with a peak in the concentration of E and F in the maternal blood and may reflect the maternal levels. There was no ‘surge’ in the concentration of total F in fetal blood at term. The concentration of E in fetal blood varied between 5 and 15 ng/ml during this last stage of gestation, hence providing ready substrate for the 11β-reductase present in lung and other tissues. The concentration of E and F in maternal blood was significantly higher and more variable than that in blood from nonpregnant female rabbits, and there was a pronounced peak in concentration at day 30 (term: 31 days). The concentrations of both E and F in amniotic fluid were lower than those in either maternal or fetal blood until day 30 when the concentration of F increased fivefold to 19.2 ± 2.58 (mean ± SEM of 6 samples).
Enterobacteria of the Neonate
Authors: Borderon J.C. , Gold F. , Laugier J.
Published: September 2009

Enterobacterial digestive tract colonization of neonates under different conditions during their first days of life was studied. Our objective is to determine the frequency of antibiotic resistance under different conditions (hospitalized newborns treated or not with antibiotics, newborns in a maternity unit, mothers treated or not) thereby permitting a better appreciation of the role played by the ‘selection pressure’ created by antibiotics commonly used in perinatology. The method used was the culture of graded newborn fecal dilutions on selective media, some of which contained antibiotics. Cultures were made every day during the 1st week and at 2 weeks of age. By using this technique, enterobacteria can be quantified as a function of their variety and of their resistance to different antibiotics. In the normal neonate under the normal conditions, the most predominant enterobacterium is an Escherichia coli sensitive to antibiotics; these infants also had several varieties of resistant enterobacteria, frequently acquired from their mothers. An antibiotic treatment of the mothers following delivery had no effect on the enterobacteria of the newborns. In a hospital setting, treated neonates rapidly acquired resistant species of enterobacteria. Nontreated neonates, initially often colonized with sensitive enterobacteria, acquired resistant enterobacteria during their first days of life.
Pituitary Response to Bilateral Adrenalectomy, Metyrapone Treatment and Ether Stress in the Newborn Rat
Authors: Hary Lionel , Dupouy Jean-Paul , Chatelain Alain
Published: September 2009

ACTH level, determined by radioimmunoassay, has been used as a reliable test to investigate pituitary response to bilateral adrenalectomy, metyrapone treatment and ether stress in 8-day-old rat newborns. The pituitary gland was able to enhance ACTH release significantly, first in response to the decrease in plasma corticosteroid levels induced either by bilateral adrenalectomy or by metyrapone inhibition of the corticosteroidogenesis, and second in response to 2 min of ether exposure. This latter response was greater in females than in males but smaller in neonates than in adults. These data suggest that the steroid-feedback mechanism was operating fully at the 8th postnatal day and that central mechanisms partially responded to external signals of stress. However, a relative ‘stress-non-responsive period’ was evident by the 8th postnatal day. The newborn rat’s hypothalamic-pituitary axis has partially matured to be responsive to stress by the end of the first week after birth.
Metabolic Activity of Developing Rat Lung
Authors: Hamosh Margit , Simon Morton R. , Mullon Darlene K. , Hamosh Paul
Published: September 2009

The uptake and metabolism of 3H-ρalmitate, 14C-choline, 14C-proline and 3H-glucosamine were studied in lung slices prepared from rats aged 2–12 days. Palmitate incorporation increased from 18.2 ± 2.8 nmol/mg protein/h 2 days before birth to 40.0 ± 4.0 nmol/mg protein/h 3 days after birth, and decreased to 24.0 ± 2.3 nmol/mg protein/h at 12 days of age, it remained at the same level in the adult lung. At all ages tested, more than 75% of the palmitic acid taken up by the lung was in esterified form. Incorporation of palmitic acid into lecithin was highest 1 day after birth. Choline incorporation into lecithin increased eightfold between 2 days before and 1 day after birth (from 0.45 ± 0.12 to 3.75 ± 0.25 nmol/mg protein/h, respectively) and decreased 60% by 12 days of age. There was no difference between the incorporation rate at 12 days and that in the adult lung (1.52 ± 0.15 nmol/mg protein/h). Total lung phospholipid increased 220% between 2 days before birth and the day of birth, and changed little thereafter. Phosphatidyl choline made up 50–60% of lung phospholipids at all ages. Proline incorporation into lung protein was highest in the perinatal period (0.57–0.58 nmol/mg protein/h 2 days before and 1 day after birth) and decreased rapidly thereafter. Glucosamine incorporation was highest in the fetal lung (0.84 ± 0.05 nmol/mg protein/h) and decreased 67% 1 day after birth, the incorporation remained between 0.1 and 0.2 nmol/mg protein/h thereafter (from 3 days to adult age). The data presented show that in the rat lung the biosynthesis of structural components and of surfactant is highest during the immediate perinatal period.
Alterations in Fetal Lung Phosphatidylinositol Metabolism Associated with Maternal Glucose Intolerance
Authors: Merritt Allen , Curbelo Violetta , Gluck Louis , Clements Rex S.
Published: September 2009

Prior to conception, female rabbits were made hyperglycemic by streptozotocin administration. Fetal hyperglycemia and hyperinsulinemia were documented. Although plasma myoinositol concentrations were higher in the fetuses of diabetic mothers, the ratio of lung to plasma myoinositol concentrations in 29-day fetal rabbits were lower than control values. CDP-diglyceride:inositol phosphatidyltransferase was reduced by 70% in the diabetic fetuses and their lung tissue phosphatidylinositol content was decreased.
Maturation of Early-Phase Insulin Release in the Neonatal Lamb
Authors: Philipps Anthony F. , Dubin Joseph W. , Raye John R.
Published: September 2009

Standardized primed continuous glucose infusions were performed in 13 newborn lambs between 4 h and 2 weeks of age to assess the timing of development of glucose-induced early-phase insulin release. Lambs of less than 6 h of age behaved similar to those previously infused in utero, with no early response noted. In contrast, early-phase insulin release was present in lambs of 12 h of age and older. Although basal plasma glucose rose with increasing post-natal age, this rise was not sufficient to account for the appearance of early-phase insulin release. Factors other than the basal glucose level or the birth process itself may be operative.
Effect of Adrenalectomy on the Transmission of IgG in Young Rats
Authors: Morris B. , Morris R. , Kenyon C.J.
Published: September 2009

Antibody transmission in rats aged 17 days was unaffected by adrenalectomy performed at 13 days. The normal Ê»closure’ of the jejunum to antibody is delayed by about 2 days in adrenalectomised rats. Adrenalectomy at 13 days has no apparent effect on plasma volume or haematocrit. Plasma corticosterone levels increase fivefold between 14 and 20 days, but in early weaned animals with Ê»closed’ guts, corticosterone levels were not raised.
Transient Apnea after an Enkephalin Analogue in the Preterm Rabbit
Authors: Hedner Thomas , Hedner Jan , Bergman Boinge , Lundberg Dag
Published: September 2009

FK 33–824, a potent enkephalin analogue was administered systemically, 0.5–5 mg/kg, to preterm neonatal rabbits. A marked decrease in respiratory frequency as well as irregular breathing and apneic spells was recorded at 5 mg/kg. Tidal volume was not affected. The enkephalin-induced respiratory depression was restored immediately after naloxone (10 mg/kg). Based on the results it may be speculated upon whether brain stem enkephalin neurons are involved in the pathogenesis of neonatal transient apnea and irregular breathing.
Relationship between Amino Acid Intake and Accretion in a Marsupial, Macropus Eugenii
Authors: Renfree M.B. , Meier P. , Teng C. , Battaglia F.C.
Published: September 2009

The total amino acid composition of 57 samples of milk was analyzed by ion exchange resin chromatography after acid hydrolysis of proteins. The concentrations of most of the amino acids in the milk increased in proportion to the increase in milk protein. Sharp increases in the sulfur-containing amino acids, cystine (and/or cysteine) and methionine occurred at around 140-160 days which is about the time of hair follicle development. The remaining amino acids reached a peak concentration by 220 days, by which stage of development the pouch young has fully developed homeothermy. These higher amino acid levels were sustained to day 260, the time of highest milk protein concentration. The amino acids provided in the milk to the suckling pouch young thus show changes in relative amounts which correlate with some of the developmental events occurring during this phase of active growth and maturation.
Unilateral Ovariectomy during Pregnancy in Well-Nourished and Undernourished Rats: Effects on Placenta and Fetal Body and Brain Growth
Authors: Croskerry P.G. , Smart J.L. , Charnock P.
Published: September 2009

The possibility that maternal unilateral ovariectomy, which is said to enhance fetal growth, might also ameliorate the harmful effects of undernutrition was investigated. Maternal undernutrition throughout pregnancy and unilateral ovariectomy on day 13 of pregnancy were investigated separately and in combination in primigravid rats with respect to male and female placental and fetal growth. Undernutrition increased the number of fetal resorptions in the 3rd week of pregnancy and depressed placental and fetal weights in both sexes, although there was some relative sparing of fetal brain weight. Unilateral ovariectomy of well-nourished mothers on day 13 of pregnancy caused significant increments in placental weight, and fetal body and brain weight in both sexes, but not in fetal length. None of these effects were observed in underfed mothers; that is, unilateral ovariectomy was ineffective in ameliorating the consequences for the fetus of maternal undernutrition. In none of the groups was there a significant relationship between fetal body weight and the number of fetuses, although in the undernourished litters significant negative correlations between fetal body weight and total number of placentae (normal and supernumerary) were found.
Role of Sex Steroid Hormones in the Normal and Glucocorticosteroid Hormone-Induced Evolution of Carbamoylphosphate Synthase (Ammonia) and Arginase Activity in Rat Liver Ontogenesis
Authors: Lamers W.H. , Mooren P.G.
Published: September 2009

The effects of sex steroid hormones on the developmental changes of carbamoylphosphate synthase and arginase activity, and DNA content in rat liver were investigated. After birth, administration of estradiol causes an increase in carbamoylphosphate synthase and arginase activity at high dosages only. Progesterone strongly inhibits or even reverses these stimulatory effects of estradiol. Administration of progesterone alone had no effects in the 1st postnatal week, a stimulatory effect in the 2nd postnatal week, and slightly inhibitory effects on enzyme activities thereafter. Testosterone hardly affected enzyme activities in the 1st 2 postnatal weeks and slightly decreased them from the 3rd postnatal week onwards. No differences in the response of either sex to these hormone treatments were observed. During the last 4 prenatal days and during the 1st postnatal week progesterone partially inhibited the prednisolone-induced enzyme accumulation and decrease in DNA content. Testosterone had such effects during the 1st 2 postnatal weeks. Comparison of these and previous experimental results with the developmental profiles of carbamoylphosphate synthase (ammonia) and arginase activity and DNA content on the one hand and with the developmental profile of steroid hormone levels on the other shows that only glucocorticosteroids influence enzyme activity and DNA content profiles, while progesterone and testosterone modulate the profiles by antagonizing the effects of glucocorticosteroids. No role for estrogens could be established.
Effect of Cortisone on Permeability of the Neonatal Rat Lung to Drugs
Authors: Hemberger Judith A. , Schanker Lewis S.
Published: September 2009

The effect of cortisone (5 mg/animal i.p. on day 5 after birth) on the development of adult-type permeability characteristics in the lung was investigated in rats 6–18 days of age. In both treated and control rats, the lipid-soluble drug procainamide was absorbed at similar rates in all age groups. In contrast, in cortisone-treated animals, pulmonary absorption rates for the lipid-insoluble compounds mannitol and p-aminohippuric acid declined to adult levels at the age of 6 days, which was 12 days earlier than in controls. Cortisone treatment thus accelerates development of adult permeability characteristics in the pulmonary epithelium.