bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Perinatal Exposure of Albino Rats to Chloroquine
Authors: Mgbodile M.U.K.
Published: September 2009

The effects of perinatal exposure of Wistar-derived albino rats to chloroquine were studied. Chronic exposure to 10 mg/kg of chloroquine phosphate during intra-uterine and postnatal life resulted in a marked decrease in neonatal and postweaning body and organ weights. The fasting blood glucose level was significantly elevated at 8 weeks of age in animals exposed to chloroquine. The observed growth retardation suggested transplacental poisoning and poisoning through milk transfer. The elevation in blood sugar level could be a consequence of possible ultrastructural and biochemical alterations of pancreatic B cells.
Adrenalectomy and Pentagastrin Effects on Gastrointestinal Cholinergic Enzyme Activities
Authors: Heitkemper M.M. , Shaver J.F.
Published: September 2009

The present study examined the effects of pentagastrin and adrenalectomy on choline acetyltransferase (ChAT) and acetylcholine esterase (AChE), enzymes which synthesize and degrade acetylcholine in the rat gastrointestinal tract. Adrenalectomized and non-adrenalectomized rats, 14 and 21 days old, were treated with either pentagastrin (250 μg/kg i.p.) or saline for 7 days. Rats were sacrificed at 21 and 28 days of age. Adrenalectomy- and pentagastrin-treated 21-day-old rats had greater ChAT activities than those treated with pentagastrin alone, while AChE activities were higher in the pentagastrin-treated group. Adrenalectomy- and pentagastrin-treated 28-day-old rats had lower levels of activity as compared to pentagastrin-treated rats. The adrenal gland does appear to influence the response of cholinergic enzyme activities to pentagastrin.
Cell Proliferation in Developing Human Jejunum
Authors: Arsenault Pierre , Ménard Daniel
Published: September 2009

Cell proliferation of the developing human jejunum was investigated by radioautography using organ culture. The sites of [3H]-thymidine uptake were localized in the epithelium, the mesenchyme and the muscularis externa of fetal human small intestinal explants from 8 to 18 weeks of gestation. Proliferating cells were abundant and scattered throughout the stratified epithelium before the appearance of villi. Many nuclei in the mesenchyme and the muscular layer were labeled. With the villi formation and the simplification of the epithelium, there was a confinement of the proliferating zone in the intervillus areas and developing crypts. The quantitation of proliferating cells showed a labeling index at its highest value between 8 and 10 weeks of gestation decreasing gradually up to 18 weeks of gestation at the epithelial and mesenchymal level. In the muscularis externa, the labeling remained more or less constant between 11 and 18 weeks of gestation. The organ culture of intestinal explants for 5 days did not modify epithelial cell proliferation. The present investigation provides for the first time basic quantitative data regarding cell proliferation in the developing human jejunum.
Heat Production and Respiratory Enzymes in Normal and Runt Newborn Piglets
Authors: Hayashi M. , Ingram D.L. , Dauncey M.J.
Published: September 2009

The heat productions of newborn runt and normal piglets were estimated over a range of ambient temperatures. Most runts increased their heat production in the cold, but when expressed as J·kg––0.67·min––1 it was significantly lower than in normal piglets (201.3 ± 16.0 and 144.7 ± 16.2 J·kg––0.67·min––1 for controls and runts, respectively, at 32 °C). Runts consequently had lower deep body temperatures (37.8 ± 0.2 and 36.8 ± 0.3 °C for controls and runts, respectively, at 32 °C). Some runts failed to increase their metabolic rate in the cold and these had the lowest deep body temperature. Activities of respiratory enzymes in heart and diaphragm muscle were similar in all animals, whereas the longissimus dorsi of runts had significantly lower enzyme activities (76.3 ± 4.2 and 55.5 ± 6.6 in absorbance units for controls and runts, respectively).
Rat Placentae Gamma-Glutamyltransferase Activity Changes during Pregnancy
Authors: Baumrucker Craig R. , Stover Rosemarie
Published: September 2009

γ-Glutamyltransferase (D-γ-glutamyl transpeptidase, EC 2.3.2.2) activity in rat placentae changes during gestation. The enzyme activity reaches a peak during the second trimester on a per gram of tissue basis and coincides with the greatest placental growth (hyperplasia) period. However, the enzyme activity on a per placenta basis shows two peak activity periods. One coincides with the peak of activity determined on a per gram basis. The second peak occurs in the third trimester and appears to coincide with the period of greatest fetal growth. The occurrence of these enzyme changes supports the concept of a developmental role for γ-glutamyltransferase in providing amino acids from glutathione to the placenta and fetus.
Reproductive Organs in Anencephaly with Special Reference to the Uterus
Authors: Zondek L.H. , Zondek T.
Published: September 2009

A survey has been made of the reproductive organs of anencephalic fetuses with special reference to the uterus and the vagina. The uteri and the vaginae of 15 anencephalic fetuses were examined and compared with 29 controls. The uterus showed normal development and reacted normally to hormonal stimulation by showing vascular, stromal and glandular proliferation and glandular diastase-resistant mucin secretion in varying degrees. All these processes were fully developed during the last month of pregnancy, offering the same picture as the controls. Cervix and vagina showed good maturation of squamous epithelium with already a fair amount of diastase-resistant mucin at 27 weeks of gestation, increasing steadily towards full term. A review of 32 postmortem records from various hospitals did not reveal any external developmental abnormalities of the uterus and its appendages in the anencephalic fetus with the exception of 2 cases. These findings are in marked contrast to the gross developmental abnormalities observed in the reproductive organs of male anencephalic fetuses.
Long-Term Variation in Oxygen Consumption Rate in Preterm Infants
Authors: Roberts Susan B. , Murgatroyd Peter R. , Crisp J.A. , Nohria Virinder , Schlingenseipen K.-H. , Lucas Alan
Published: September 2009

An investigation was made of long-term variation in oxygen consumption rate (VO2) in preterm infants. Four subjects (gestational age 27–34 weeks, postnatal age 17–38 days, weight at study 1.1–2.6 kg) were studied for 5 days each using open-circuit, indirect calorimetry. The mean VO2 for each subject (11.0–11.5 litres/kg/day) was within the reported range. However, the between-subject coefficient of variation during the study (2.1 %) was smaller than the mean between-measurement coefficient of variation for daily VO2 (3.8%, range 1.7–6.3%). In addition, the between-measurement coefficient of variation was increased further for measurement intervals of less than 24 h (reaching a mean of 8.3% for 1-hour periods), and a relationship between measurement duration and the precision of estimating VO2 over 3 or 5 days is described. Thus, even 24-hour measurements of VO2 in these preterm infants were less representative of the individual’s VO2 over 3 days than the group mean estimate. This finding is of relevance to future studies in this area, particularly those in which short-term measurements of energy expenditure are combined with a nutrient balance study to determine the composition of weight gain, because even small errors in the estimate of total energy expenditure can lead to unacceptably large errors in calculated energy deposition.
Human Umbilical Arteries and Veins: Generation of Leukotrienes and Response to Exogenous Leukotrienes
Authors: Piper Priscilla J. , Levene Sara
Published: September 2009

When human umbilical arteries and veins were challenged with calcium ionophore A23187 they released a leukotriene (LT)-like material. On bioassay using guineapig ileal smooth muscle, the release was equivalent to 37.4 ± 7.5 ng LTD4 (mean ± SEM) per gram of arterial tissue, and 29.0 ± 4.7 ng LTD4/g of venous tissue. The LT was further purified by high pressure liquid chromatography, and characterised as LTC4 by bioassay and radioimmunoassay of purified fractions. Longitudinal strips from human umbilical arteries in vitro did not contract to doses of synthetic LTD4 in the range 5 × 10––11 to 10––9 mol.
Reliability of Urinary N-Acetyl-β-D-Glucosaminidase as an Indicator of Renal Tubular Damage in Neonates
Authors: Watanabe Kazuo , Kojima Takatsugu , Fukuda Yuka , Ohbayashi Kazuhiko , Kobayashi Tatsuharu , Iwase Suiko , Kobayashi Yohnosuke
Published: September 2009

Urinary N-acetyl-β-D-glucosaminidase (NAG) was determined in infants during the first year of life to clarify its evolutional change and the reliability of this enzyme as a marker of renal tubular damage in the newborn period. During the first 2 weeks of life, there was no difference in the urinary levels between preterm (gestational age of 33–36 weeks) and full-term infants. The urinary NAG index (NAG is expressed as the ratio of the enzyme activity to milligrams of creatinine) during the first month of life was significantly elevated when compared with that of any other succeeding period and gradually decreased during the first year of life. The index in newborn infants on tobramycin was significantly elevated and maintained a higher value during the 5 days after withdrawal of the medication. Infants with asphyxia had a higher urinary NAG index during the first week of life. These data suggest that the urinary NAG index is a useful indicator of renal tubular damage during the newborn period.
Effect of Dexamethasone on the Adenylate Cyclase System of Cultured Hepatocytes of Fetal Rats
Authors: Nishida Naoki , Takeuchi Taishi
Published: September 2009

During treatment of primary cultured hepatocytes with dexamethasone for several hours, cyclic AMP formation and glycolysis by glucagon increased dose dependently. In the cells pretreated with dexamethasone, the output of intracellular cyclic AMP increased significantly (p < 0.01) with glucagon of 2.8 × 10––9M or more, and the amount of glucose released also increased significantly (p < 0.01) with glucagon of 2.8 × 10––8M or more, compared to the control cells. Moreover, treatment with dexamethasone increased the stimulatory effect of guanosine-5′-triphosphate (GTP), guanyl-5′-yl-imidodiphosphate on adenylate cyclase and significantly increased the stimulatory effect of fluoride. In the rat hepatocytes primarily cultured with dexamethasone for several hours, the stimulatory effect of GTP and fluoride on adenylate cyclase increased time dependently. These data indicate that the glucocorticoid regulates the sensitivity of adenylate cyclase at distinct loci of the post-receptor system.
Biochemical Maturation of Fetal Rat Lung: A Comprehensive Study Including Surfactant Determination
Authors: Bourbon Jacques R. , Farrell Philip M. , Doucet Edith , Brown Jeannette , Valenza Cécile
Published: September 2009

The paper describes a comprehensive assessment of lung growth and biochemical maturation in the fetal and early postnatal rat. Fetal lung grew faster than whole body between gestational day 16.5 and term. Cell number increased quasi-exponentially, except for a slowing of cell growth between days 19.5 and 20.5 of gestation. By contrast, growth was limited during the two first postnatal days. Percentage of dry tissue and protein concentration increased in parallel during the whole period. Increases in whole lung tissue phosphatidylcholine were greatest between 20.5 and 21.5 days of gestation, whereas in isolated surfactant fraction, changes were most marked between 19.5 and 20.5 days. The most striking changes were a 19-fold increase in phosphatidylcholine and a 12.5-fold increase in the total phospholipid concentrations in the surfactant fraction between gestational day 19.5 and 1 day postpartum. Similar changes occurred in disaturated phosphatidylcholine (DSPC) concentration. During the same period, phospholipids of the residual (nonsurfactant) fraction increased only about 2-fold. These data indicate that analysis of an isolated surfactant fraction is advantageous in providing a very sensitive index of augmented phospholipid production during the process of fetal lung maturation. Evidence of biochemical maturation was detected earlier in females than in males, as indicated by a significantly larger surfactant fraction DSPC concentration in 19.5-day-old females; however, this difference was modest in degree and very transient, since it was no longer demonstrable in later stages.
Ketogenesis in Hypoglycemic Neonates
Authors: Sann L. , Divry P. , Cartier B. , Vianey-Laud C. , Maire I.
Published: September 2009

Since hypoglycemic neonates do not exhibit compensative ketosis, we investigated the possible involvement of carnitine deficiency or Ω-oxidation in neonatal hypoglycemia. In a first group of 49 neonates, serum free fatty acid, acetoacetate and β-hydroxybutyrate concentrations were similar in hypoglycemic and normoglycemic neonates. Serum free carnitine concentrations did not show any difference in the hypoglycemic small-for-date infants (median 40 μmol/l, range 16–92 μmol/l) compared to the normoglycemic small-for-date infants (median 30 μmol/l, range 8–64 μmol/l). In a second group of 45 neonates, urinary excretion of dicarboxylic acids (adipic, suberic, sebaric and succinic acids) was similar in hypoglycemic infants compared to normoglycemic neonates. Despite the limitations of interpretaion of free carnitine determination, these data do not suggest an impaired β-oxidation by carnitine depletion or an enzymatic defect in hypoglycemic neonates.
Synthesis of Prostaglandins and Lipoxygenase Products by Rat Glomeruli during Development
Authors: Bensman A. , Sraer J. , Delarue F. , Bens M. , Vasmant D. , Sraer J.D.
Published: September 2009

In glomeruli isolated from adult rats, arachidonic acid (C20:4) is metabolized through at least two different pathways: the lipoxygenase and the cyclooxygenase pathway, resulting in the synthesis of 12-hydroxyeicosatetraenoic acid (12-HETE) and four prostaglandins (PG) respectively. Because renal blood flow (RBF) and glomerular filtration rate (GFR) increase during development, and because C20:4 metabolites are implicated in their local regulation, the conversion of 3H-C20:4 was studied in 3 groups of rats; group A: 4 days old, 10 g; group B: 10 days old, 25 g; group C: 60 days old, 200 g. Glomeruli mechanically isolated from blanched kidneys were incubated with 5.4 × 10––8M3H-C20:4. Lipoxygenase and cyclooxygenase products were extracted and resolved by high-performance liquid chromatography (HPLC); quantitative determination of PGs was performed by radioimmunoassay (RIA). The results are: (1) conversion of C20:4 to lipoxygenase product is predominant in comparison to cyclooxygenase products; (2) conversion of labeled C20:4 into 12-HETE is constant with age; (3) identified cyclooxygenase products, PGE2, and particularly PGF2α are maximum in group B; (4) the variation of C20:4 metabolism during development suggest that these products may be involved in the maturation and the regulation of glomerular functions.
Transplacental Stimulation of Fetal Lung Maturation: Effect of Triiodothyronine in the Female and Male Rabbit Fetus
Authors: Church John , Khafayan Edward , Chechani Vijay , Sadiq Farouk , Devaskar Sherin , deMello Daphne , Devaskar Uday
Published: September 2009

We have recently demonstrated that intramuscular administration of triiodothyronine (T3) or thyroxine (T4) to the rabbit doe results in its transfer across the placenta. In this study we investigated the effect of maternally administered T3 upon the functional and morphologic fetal lung maturation. T3 (175 μg/kg) or the vehicle was injected intramuscularly into the New Zealand White rabbit does on days 25 and 26 of gestation. On day 27 of pregnancy, the does were killed and the fetuses were delivered. Maternal and fetal plasma T3, glucose and insulin and fetal plasma corticosteroid concentrations were determined. The functional pulmonary maturity was assessed by performing the pressure-volume hysteresis while morphologic maturity was established by histologic techniques. Enhanced functional as well as morphologic fetal lung maturation was observed in female as well as male fetuses in T3-treated aninmals. However, there was a significant increase in the fetal mortality after T3 treatment, and the duration of survival in the extrauterine environment on premature delivery was not prolonged.
Effect of Maternal Fasting on Ovine Fetal and Maternal Branched-Chain Amino Acid Transaminase Activities
Authors: Liechty Edward A. , Barone Suzanne , Nutt Mitchell
Published: September 2009

Activities of branched-chain amino acid transaminase were assayed in maternal skeletal muscle, liver and fetal skeletal muscle, cardiac muscle, liver, kidney and placenta obtained from fed and 5-day-fasted late gestation ewes. Very high activities were found in placenta; fetal skeletal muscle also had high activity. Fetal brain had intermediate activity, followed by cardiac muscle and kidney. Fetal liver possessed negligible activity. Activities were low in both maternal liver and skeletal muscle. Trends were seen for fasting to increase activities in fetal placenta, skeletal muscle, brain, kidney, heart and maternal liver, but these changes were statistically significant only for fetal brain and placental tissue. Fetal skeletal muscle activity was 100 times that of maternal skeletal muscle. These data imply differences in the metabolism of the branched-chain amino acids by fetal and adult ruminants and expand the thesis that branched-chain amino acids are important to the metabolism of the ovine fetus.
Effect of Hypophysectomy on Tissue Glycogen Concentrations in the Fetal Pig
Authors: Randall G.C.B.
Published: September 2009

The glycogen content was estimated in the liver, lung, cardiac ventricle and skeletal muscle of fetal pigs which had been hypophysectomized between 69–84 days of gestation, decapitated between 35–42 days of gestation or left intact. Comparisons made preterm (103–108 days) or at term (112–114 days) indicated that both liver and skeletal muscle glycogen content were significantly lower in the absence of the fetal pituitary, whereas concentrations in the fetal lungs were significantly higher. There were no significant differences in cardiac glycogen content between hypophysectomized and intact fetuses. Plasma glucose concentrations in both umbilical artery and vein were similar, but plasma arterial fructose concentrations were significantly higher in the hypophysectomized fetuses.
Composition of Weight Gain during the Neonatal Period and Longitudinal Growth Follow-Up in Premature Babies
Authors: de Gamarra M.E.. , Schutz Y. , Catzeflis C. , Freymond D. , Cauderay M. , Calame A. , Micheli J.L. , Jequier E.
Published: September 2009

Changes in the rate of growth and adiposity index (Quetelet index), calculated as weight/(length)2, kg/m2, were monitored from birth to 3 years in 19 premature babies (post-conceptional age 31.2 ± 2 weeks) who were subjected during rapid growth (16 ± 4 g/kg·day) to initial metabolic balance studies in the first weeks of life. These studies showed that the rate of fat accretion in these infants (3.3 ± 0.9 g/kg·day) was substantially greater than that observed in fetuses of the same gestational age (2 g/kg·day) but the adiposity index was lower (9.6 ± 1 kg/m2) than intrauterine values (11 kg/m2). Since at 6 months of age (corrected for gestational age at birth) the adiposity index was close to normality (103% of standard), the greater rate of fat accretion in early life contributed to progressively restore total body fat in premature babies. It is concluded that despite substantial fat deposition during the first weeks of life, the future evolution of these premature babies is favourable as judged from the normalization of adiposity index within the first 2 years of life.
Respiratory Gases, Acid-Base Balance and Lactate Concentrations of the Midterm Human Fetus
Authors: Bozzetti Patrizia , Buscaglia Mauro , Cetin Irene , Marconi Anna Maria , Nicolini Umberto , Pardia Giorgio , Makowski Edgar L. , Battaglia Frederick C.
Published: September 2009

Respiratory gases, acid-base balance, and lactate and hemoglobin concentrations were measured in 14 fetal blood samples between 17 and 21 weeks of gestation. The samples were obtained at the time of fetoscopy performed for prenatal diagnosis. Results have been compared with two reference groups: (a) 4 patients in whom fetal cord blood sampling was performed at 32–36 weeks of gestation, and (b) 10 patients at the time of elective cesarean section, 35–39 weeks. PO2 and oxygen saturations were significantly higher and hemoglobin concentration lower in the mid-gestation fetus. Acid-base balance was not significantly different. There was a significant correlation between maternal and fetal hemoglobin concentrations. The oxygen affinity of fetal blood was not significantly different from that described for term fetuses with a oxygen saturation of less than 90%.
Lipid Peroxidation and Vitamin E Levels during Pregnancy in Rats
Authors: Yoshioka Tamotsu , Motoyama Hiroaki , Yamasaki Fumiyuki , Ando Masaaki , Takehara Yoshiki , Yamasaki Madoka
Published: September 2009

The present study examined pregnancy-related changes in the level of lipoperoxides and antioxidative substances such as superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px) and vitamin E in the maternal and fetal serum, liver, lungs and placenta using Wistar rats. Pregnant rats fed a standard diet (control animals) showed an increase of lipoperoxides in the blood to a level 3 times greater than the non-pregnant level. When the rats were fed a vitamin E-deficient diet, lipoperoxides were produced in much greater amounts. Fetal blood also contained greater concentrations of lipoperoxides by the use of a vitamin E-deficient diet. However, liver and lung tissues contained lipoperoxides in essentially constant concentrations throughout non-pregnancy and pregnancy. Fetal liver and lung tissues showed higher concentrations than the maternal concentrations. Fetal blood and tissue concentrations of vitamin E reflected the maternal concentrations, and the values in vitamin E-deficient animals were as small as 0.1–0.2 of the values in normally fed animals. As a protective factor against lipid peroxidation, SOD was slightly increased in the liver tissues of pregnant control animals, but catalase and GSH-Px were significantly decreased in the organ. A similar tendency was observed in vitamin E-deficient animals.
Lung as a Possible Additional Target Organ for Vitamin D during Fetal Life in the Rat
Authors: Nguyen Minh , Guillozo Huguette , Garabédian Michèle , Balsan Sonia
Published: September 2009

The presence of specific cytosol binding sites for 1,25-(OH)2D3 was evaluated in rat fetal tissues during the last quarter of gestation (days 17–21). The content of 1,25-(OH)2D3-binding sites was low in intestine, brain, liver, spleen, pancreas, sternum and thymus during the period of gestation studied. It was highest in skeleton (ribs and vertebral bodies), kidney and lung from day 19 onwards. In the cytosol of these latter tissues, a high affinity (Kd 0.7–3.6 × 10––10M), low capacity [3H]1,25-(OH)2D3 binding was demonstrated and a distinct 2.9- to 3.5-S [3H]1,25-(OH)2D3-binding component was observed. These findings suggest that fetal lung, skeleton and kidney are possibly major target tissues for 1,25-(OH)2D3.
Inhibitory Action of Bilirubin on Superoxide Production by Polymorphonuclear Leukocytes
Authors: Nakamura Hajime , Uetani Yoshiyuki , Komura Miyoji , Takada Satoshi , Sano Kimihiko , Matsuo Tamotsu
Published: September 2009

To assess the interaction of bilirubin with albumin and to determine the site of bilirubin toxicity in cells, a study was made of the O2 production of neonatal neutrophils (PMNs) by two different stimulators: (1) concanavalin A (Con A) plus cytochalasin D (Cyt D), which acts on the cell surface, and (2) phorbol myristate acetate, which acts intracellularly. PMNs that had been separated from cord blood were incubated for 60 min at 37 °C in the solution with different molar ratios of bilirubin/albumin (unbound bilirubin, ranging from 0.35 to 3.92 μg/dl). The unbound bilirubin was determined by peroxidase oxidation method. A PMN viability of more than 96% was maintained after the incubation in each of solutions. The O2 production rate of PMNs stimulated by Con A plus Cyt D was inhibited in the presence of unbound bilirubin levels as low as 1.12 μg/dl, and the rate decreased as the levels of unbound bilirubin rose. The O2 production rate stimulated by Con A plus Cyt D was more remarkably inhibited than that by phorbol myristate acetate, which directly activates intracellular protein kinase C. These findings suggest that bilirubin toxicity to PMN can be shown at levels of unbound bilirubin as low as those in hyperbilirubinemic sera, and the critical site at which bilirubin exerts its toxicity is mainly in membrane level rather than on intracellular functions.
Influence of Food Intake during Late Gestation on Serum Lipids of Sows and Their Progeny
Authors: Walsh Hentges Lynnette S. , Williams Amy C. , Mangham William A. , Martin Roy J.
Published: September 2009

Serum and lipoprotein lipids were quantified in pregnant and nonpregnant sows allowed restricted and ad libitum access to a low-fat cholesterol-free diet, and in the progeny of these sows. Pregnant sows exhibited a mild increase in serum triglycerides in the third trimester, reflecting an increase in very low density lipoprotein (VLDL)-triglyceride concentration. Ad libitum feeding enhanced this increase. Free fatty acids were depressed in mid-pregnancy (60 days gestation), but were normal or elevated in the final trimester. Total cholesterol was similar in all groups. Pregnancy and level of food intake interacted to increase VLDL-cholesterol in pregnant sows fed ad libitum. Pregnancy decreased high density lipoprotein cholesterol. Level of food intake by sows had no influence on serum lipid concentrations of newborn pigs. Distribution of cholesterol and triglyceride between lipoprotein classes was different in newborn pigs when compared to sows. These results imply fetal self-regulation of lipid metabolism during late gestation. Sow serum lipids are not identical to those in humans. However, when fed a modified diet that resembles a human diet, sows may be useful as a model for humans in studies of lipid metabolism during pregnancy.
Percutaneous Respiration in the Newborn Infant
Authors: Cartlidge P.H.T. , Rutter N.
Published: September 2009

Percutaneous respiration was studied in 32 newborn infants between 25 and 41 weeks gestation, using a closed skin cell attached to the abdomen. Gas exchange rates in the first few days of life were 6–11 times faster in infants below 30 weeks gestation than in term infants (mean O2 absorption 25.0 vs. 206.5 ml/m2/h, and CO2 excretion 26.0 vs. 294.6 ml/m2/h), but rates were similar by 3 weeks of age. Increasing the ambient oxygen concentration resulted in a non-linear increase in oxygen absorption, particularly in the most immature infants. Below 30 weeks gestation, O2 absorption increased from a mean of 206.5 ml/m2/h in air, to 357.2 ml/m2/h in 40% oxygen and 573.5 ml/m2/h in 90% oxygen. We estimate that an infant below 30 weeks gestation, nursed naked in 90% oxygen, would obtain up to 20 % of resting oxygen requirements percutaneously.
Ontogenic Changes in Serum Immunoglobulins and C3 in Vitamin-D Deficient and Malnourished Rats
Authors: Srimaruta Nualanong , Lee P.C. , Lebenthal Emanuel
Published: September 2009

In both protein energy malnutrition and vitamin D deficiency, defects in some immunological functions have been noted, but the effects on complement and immunoglobulin concentrations have not been evaluated. We assessed the effects of malnutrition and vitamin D deficiency on immunoglobulins and C3 in rats in early postnatal life during weaning and early adulthood using the rocket immunoelectrophoresis technique. In well-nourished rats, the serum levels of IgG increased from 88.5 ± 10.2 mg/dl in the newborn period to 883.4 ± 104.8 mg/dl at weaning (day 19). The adult levels, 1,325.9 ± 60.8 mg/dl, were attained by 35 days of age. Serum IgA was not detectable by our method until 20 days of age (1.1 ± 0.2 mg/dl) and reached adult levels (13.4 ± 3.2 mg/dl) by day 35. IgM was detectable in the serum of pups at 5 days of age (0.4 ± 0.07 mg/dl), increased to 27.5 ± 6.9 mg/dl at weaning and approached adult levels (93.7 ± 9.9 mg/dl) at day 35. C3 levels at birth were only 36% of adult levels and did not change during the suckling period. They then increased to levels comparable to those of adults at the age of 35 days. Serum immunoglobulins and C3 in malnourished rats were not significantly different from age-matched control pups. In pups born to dams fed a vitamin-D-deficient diet from 3 weeks of age, only the serum IgG and C3 levels were significantly lower than those of normal pups at day 1 (IgG level: 65.2 ± 6.1 vs. 88.5 ± 10.2 mg/dl; C3 level: 20.3 ± 6.9 vs. 36.2 ± 3.1% of an adult level; p < 0.005). Thus the increased susceptibility of malnourished young animals to infection does not appear to be related to a lowering of serum immunoglobulin and complement concentrations.
Effect of Increased Intracranial Pressure on Blood Pressure, Heart Rate, Respiration and Catecholamine Levels in Neonatal and Adult Rabbits
Authors: Ogilvy Christopher S. , DuBois Arthur B.
Published: September 2009

The effect of increased intracranial pressure (ICP) on heart rate, respiratory rate and blood pressure was measured in 2-day-old and adult rabbits. Neonates and adults exhibited the Cushing reflex with hypertension, bradycardia and decreased respirations when exposed to elevated ICP. Adult animals had a lower threshold of response to elevated ICP, implying a more sensitive adrenergic response compared to neonates. Although control levels of epinephrine and norepinephrine were higher in neonates compared to adults, the ratio of maximum concentration during increased ICP to control concentration was higher in adults (27.0 for epinephrine and 25.2 for norepinephrine in adults: 3.5 for epinephrine and 2.93 for norepinephrine in neonates). Injection of epinephrine was used to induce a maximal sympathetic response in both groups of rabbits studied. In adults, the cardiovascular response was the same after injection of epinephrine or after increasing ICP. In neonates, the blood pressure rise after injection of epinephrine was significantly higher (p < 0.05) than the blood pressure rise after increasing ICP. The results demonstrate an immature adreno-medullary axis in neonates who have higher resting levels of catecholamines with a relatively smaller increase in catecholamines in response to stress when compared to adults.
Endogenous Opioid Effect on Breathing during Normoxia and Hypoxia in Developing Swine
Authors: Moss Immanuela R. , Sugarman Lynn M. , Goode Debra L.
Published: September 2009

In normoxia, the opioid antagonist naltrexone (3 mg/kg i.v.) increased respiratory drive (dITP/dt), frequency (f) and ventilation (V) and decreased tidal volume (Vt) in 1-to 4-day-old anesthetized piglets; it increased dITP/dt in 10- to 18-day-old piglets. During progressive and steady state hypoxia, naltrexone increased dITP/dt, f and V within each age group. In progressive hypoxia, dITP/dt increased from the young to the old; this difference was abolished by naltrexone. Thus, it appears that (1) endogenous opioids modulate breathing in young more than in older piglets during normoxia; (2) during hypoxia, opiates modulate breathing of both young and older piglets, and (3) the increase in hypoxic respiratory drive with age may be related to enhanced respiratory suppression by opioids during hypoxia in the youngest animals. Lastly, respiratory drive is a sensitive measure of subtle differences between two closely related age groups.
Oral Epidermal Growth Factor Is Trophic for the Stomach in the Neonatal Rat
Authors: Falconer John
Published: September 2009

The stomach of the naturally suckled rat pup was shown to grow rapidly during the first 24 h following delivery. Both absolute weight (p < 0.001) and weight in proportion to body weight (p < 0.001) increased. The stomachs of pups fed formula containing epidermal growth factor (EGF) were larger than those of their control littermates (p < 0.05). These data support a role for milk EGF in the regulation of neonatal gut growth.
New Perspectives in Neonatal Nutrition
Authors: Swyer Paul R.
Published: September 2009

Modern techniques of cardiopulmonary life support, particularly for very low birthweight infants and those suffering from major surgical conditions, has presented the neonatologist with a completely new population of infants for whom continued survival and further normal physical and mental growth and development are critically dependent on adequate nutrition. The uncertainties surrounding the definition of ‘adequacy’ as well as the techniques and difficulties of its attainment and assessment are exposed. This paper examines desirable goals to be aimed for in the nutrition of the neonate in relation to genetic potential for growth, development and body composition. There is discussion of current research into the intermediary metabolism and utilisation of macronutrients and certain minerals for energy production and tissue growth and of methodology for determining body composition. The editor has also allowed a certain licence for speculation concerning future directions in neonatal nutrition.
Energy Balance and Composition of Body Weight
Authors: Putet G. , Senterre J. , Rigo J. , Salle B.
Published: September 2009

Weight gain composition of growing very low birthweight (VLBW) premature infants can be assessed by a combined technique of nutrient balance and indirect calorimetry measurement. Both protein and energy intakes play an important role in the rate of growth and in the amount of non-protein energy (i.e. fat) storage. High energy intake is not always correlated with a higher rate of growth and can lead to high fat storage.
Significance of Plasma Amino Acid Pattern in Preterm Infants
Authors: Rigo J. , Senterre J.
Published: September 2009

Nutritional studies frequently take into consideration plasma amino acid concentrations in order to evaluate the adequacy of protein intake in preterm infants. From our data of more than 100 determinations of plasma amino acid concentrations in preterm infants, we review the factors influencing the aminogram. Method and moment of sampling, protein intake and composition, protein turnover rate, energy supply, and gestational age, all may influence plasma amino acid concentrations. It is suggested that the cord blood amino acid concentration may be considered as an appropriate value of reference and a safe level for growing preterm infants.
Lipid Metabolism in Premature Infants
Authors: Hamosh Margit
Published: September 2009

Fats provide 40–50% of the total calories in human milk or infant formula. The milk secreted by mothers of preterm infants differs in fat composition from that of mothers of full-term infants in having higher levels of medium chain fatty acids (C12, C14) throughout the first 3 months of lactation, and higher levels of long chain polyenoic fatty acids during the first 3 months of lactation. These differences in composition benefit the preterm infant by providing higher levels of rapidly absorbed medium chain fatty acids and long chain polyenoic fatty acids needed for brain development. Fat digestion: The low levels of pancreatic lipase and bile salts in the preterm infant are compensated for by lipolysis in the stomach by lingual and gastric lipase and by the intestinal hydrolysis of fat through the action of human milk bile salt-stimulated lipase. Fat digestion is efficient in the preterm infant who absorbs about 80–90% of ingested fat. Lipid clearing from the circulation depends upon the activity of the enzymes lipoprotein lipase, hepatic lipase, and lecithin-cholesterol acyltransferase. The activity of these enzymes is lower or equal to that of term infants, depending upon the degree of prematurity and the nutritional regimen, especially in parenterally fed infants.
Taurine and the Premature
Authors: Ghisolfi J.
Published: September 2009

In the human fetus and in the early postnatal period, during development, the total body taurine content, particularly of the brain, increases markedly. It can be estimated that the human fetus accumulates approximately 50–60 μmol/24 h during the last 4 weeks of pregnancy. As there is evidence for the relative inability of infants to synthesize taurine, this nitrogen compound has to be wholly supplied by the mother during pregnancy and by diet after birth, particularly for the prematures who have to constitute appreciable reserves in their tissues. In adults (mammals and humans), it has been shown that the slowly exchangeable pool of taurine (mainly brain and muscles) cannot be increased by exogenous taurine but, in growing mammals, taurine from diet is rapidly transferred to tissues. Although no real proof yet exists, it seems probable that taurine should be considered an essential nutrient for premature infants.
Vitamin D Metabolism in Preterm Infants
Authors: Salle B.L. , Senterre J. , Glorieux F.H. , Delvin E.E. , Putet G.
Published: September 2009

Perinatal metabolism of vitamin D was studied in premature babies with the aim of: (1) reporting the relationship between the pregnant mother and her preterm infant and the metabolism of vitamin D during the first weeks of life, and (2) assessing the effect of vitamin D metabolites on phosphorus calcium and magnesium intestinal absorption. There was only a positive correlation between plasma cord calcium and 25-hydroxyvitamin D levels and the mother’s plasma levels at birth. During the hypocalcemic episode observed during the first week of life, vitamin D activation did occur, but later on rickets or osteomalacia cannot be due to the low levels of vitamin D metabolites in the preterm receiving an adequate dose of vitamin D (1,000–1,200 IU of D2). Calcitriol, the major metabolite of vitamin D, is acting on the intestine and promotes calcium absorption even in very tiny prematures. The pathogenesis of hypomineralization in the preterm infant is due to the low intake of calcium or phosphorus and/or poor absorption of calcium in the case of vitamin D deficiency.
Effect of Vitamin E Substitution in Very Low Birth Weight Infants
Authors: Celenk A. , Tuchschmid P. , Rieser F. , Duc G.
Published: September 2009

Vitamin E supplementation was investigated in 38 very low birth weight infants after intramuscular substitution with two doses of 25 mg given on the 1st and 3rd day of life. Plasma and red cell concentrations of the biologically inactive tocopherol acetate and the active tocopherol were followed during the first month of life. Plasma levels of this substitution regime were compared with recent clinical studies. Although the applied dose was low in comparison to other studies, the levels obtained exceed the critical concentration of 12 μM which was reported to prevent retinopathy. Concentrations associated with side effects (84 μM) were found in nearly 50% of the babies but only for short duration (24 h). In more than 80% of the infants, biologically inactive tocopherol acetate was detected in plasma up to 1 day after substitution but not in red cells.
Does Diet in Preterm Infants Influence Clinical Outcome?
Authors: Lucas Alan
Published: September 2009

After several decades of intensive research into feeding preterm infants, it is important to question why there is persisting uncertainty over their dietary management. The evolution of scientific investigation in this field is compared with that in other areas of clinical science, where a three-phase pattern emerges: phase 1 reports of anecdotal observation and clinical experience; phase 2, epidemiological observation and physiological experiment; and phase 3, controlled prospective trials of specific interventions on clinical outcome. It is argued that research into feeding preterm infants has not evolved beyond physiological experiment (phase 2) and that the absence of clinical outcome data (phase 3 research) explains major uncertainties in clinical practice. Data from a large randomized multicentre outcome study of preterm nutrition are used to demonstrate how the wealth of previous and current ‘physiological’ information cannot be used satisfactorily to predict desirable clinical outcome responses to early diet.
Left Ventricular Diastolic Function during the First Month of Life
Authors: Fouron Jean-Claude , Heitz François , Carceller Anna-Maria , Ducharme Gilles , van Doesburg Nicolaas H. , Davignon André
Published: September 2009

In order to assess possible changes in myocardial relaxation occurring during the neonatal period, M-mode echocardiograms were recorded serially in 9 normal term infants and in another group of 10 one-month-old infants. The tracings were studied with an M-mode calculator. Although individual variations were greater in the data collected during the first 24 h, no significant difference was found in the indices of diastolic function of the left ventricle during the first 4 days of age. The following changes were observed between data recorded at 4 days and 1 month, respectively: normalized peak rate of left ventricle filling, 4.03 vs. 4.71 cm/s; diastolic peak velocity of early posterior motion of aortic root, 1.89 vs. 5.15 cm/s; peak velocity of left ventricle posterior wall motion in diastole, 3.31 vs. 3.50 cm/s; mitral valve EF slope, 59.05 vs. 84.92 mm/s; left ventricle isometric relaxation time, 43.88 vs. 28.50 ms. In conclusion: (1) greater individual variations are observed in indices of left ventricle diastolic function during the first day of life, and (2) significant increase in left ventricle compliance occurs during the first month of life. These changes should play a critical role in the clinical course of newborn with cardiopulmonary disease.
The Ontogeny of Serum Immunoreactive Pancreatic Lipase and Cationic Trypsinogen in the Premature Human Infant
Authors: Cleghorn Geoffrey , Durie Peter , Benjamin Lynne , Dati Francesco
Published: September 2009

We evaluated the development of the exocrine pancreas in 16 healthy preterm infants (29.3 ± 1.6 weeks). The infants were fed breast milk with formula supplements (n = 8) or formula alone (n = 8). Growth was monitored weekly for 12 weeks then at 3, 6, 9, 12 months. At the same intervals sera were determined for pancreatic lipase and cationic trypsinogen. In addition, cord blood samples were analysed from another 33 preterm (27.6 ± 5.2 weeks) and 75 healthy full-term infants. Serum pancreatic lipase in the cord blood of term (3.7 ± 0.4 μg/l) and preterm infants (1.8 ± 0.2 μg/l) was significantly below values reported for older children (10.5 ± 0.9 μg/l; p < 0.001). In the preterm infant, serum lipase was also significantly lower than values obtained at term (p < 0.001). At birth, serum trypsinogen for preterm (16.8 ± 1.3 μg/l) and term infants (23.3 ± 1.9 μg/l) were below those for older children (31.4 ± 3.7 μg/l; p < 0.05). Over the first 3 weeks of life, serum lipase and trypsinogen increased significantly. From 3 weeks to 12 months of age, serum trypsinogen values remained unchanged, but serum lipase increased dramatically after 10 weeks of age. Thus, at 6 and 12 months of age, the preterm infants had significantly higher serum lipase values than infants of the same age born at term. These two pancreatic enzymes appear to show independent age-related maturation in infants born before term. The rate of maturation of lipase appears to be accelerated by exposure to the extrauterine environment.
Clearance of Treatment Doses of Surfactant
Authors: Pettenazzo Andrea , Jobe Alan , Ikegami Machiko , Seidner Steven
Published: September 2009

Three-day-old rabbits were given intratracheal injections with a variety of surfactants at doses of about 100 mg lipid/kg, doses commonly used in clinical trials of surfactant for respiratory distress syndrome. Calf and sheep natural surfactants isolated by centrifugation of alveolar washes were compared with Surfactant-TA and two aggregate sizes of lipid solvent extracted sheep surfactant by measuring the percent recoveries of labeled phosphatidylcholine in alveolar washes and lung tissue at times to 48 h after surfactant injection. Surfactant-TA and the lipid extracted surfactants did not contain the 28 to 35-kdalton surfactant protein. All surfactants had similar linear clearance rates from the total lung (alveolar wash plus lung tissue), independent of species source, extraction with lipid solvents, or aggregate sizes of the phospholipids in suspension. There were no metabolic consequences to lipid extraction, the loss of 28–35 kdaltons of protein, or changes in aggregate sizes of surfactant lipids when injected in treatment doses into the airways of 3-day-old rabbits.
Metabolism of Mono-(2-Ethylhexyl)phthalate in Fetal, Neonatal and Adult Rat Liver
Authors: Sjöberg Per , Bondesson Ulf , Gustafsson Jan
Published: September 2009

The aim of the investigation was to study to what extent maturity influences the metabolism of mono-(2-ethylhexyl)phthalate (MEHP), the primary metabolite of the plasticizer di-(2-ethylhexyl)phthalate. The conversion of MEHP to its (ω-1 )-hydroxylated product was determined in liver microsomes from fetal, neonatal (1- and 5-day-old) and adult rats. Product formation was determined by gas chromatography-mass spectrometry. The results show that fetal and neonatal as well as adult rat livers are capable of metabolizing MEHP by (ω-1)-hydroxylation. Preparations from 1- and 5-day-old rats were much more efficient than those from fetal rats. The transition into adult life gave no further increase in hydroxylase activity as compared to that in 5-day-old rats. The work shows that there is a rapid postnatal development of MEHP (ω-1)-hydroxylase activity in the rat.
Effect of Distal Endotracheal Bias Flow on PaCO2 during High Frequency Oscillatory Ventilation
Authors: Bancalari Aldo , Bancalari Eduardo , Hehre Dorothy , Suguihara Cleide , Gerhardt Tilo , Goldberg Ronald N.
Published: September 2009

In order to evaluate the effect of distal endotracheal bias flow during HFOV on PaCO2 we studied adult rabbits with normal lungs and those who had meconium-induced lung dysfunction. Animals were studied while 1.0, 1.4 and 1.8 ml/kg tidal volumes (VT) were delivered by a high frequency oscillator. In animals with normal lungs and a 1.0 liter/min distal bias flow, the PaCO2 decreased significantly (p < 0.01) with all VT used. In animals with meconium instillation the decrease in PaCO2 was also significant (p < 0.05) at all combinations of VT and distal bias flow. The higher the distal bias flow the more pronounced was the lowering effect on PaCO2 We conclude that during HFOV it is possible to improve CO2 elimination using small additional bias flow delivered near the tip of the endotracheal tube in animals with normal and abnormal lung function. This may allow adequate alveolar ventilation with even smaller VT, thus reducing the risk of barotrauma.
Aspartate Aminotransferase and Alanine Aminotransferase Serum Activities in Neonatal Transient Myocardial Ischemia
Authors: Zanardo V. , Vispi L. , Rizzo L. , Cittar H. , Pellegrino P.A.
Published: September 2009

The behavior of serum aspartate aminotransferase and alanine aminotransferase was evaluated during the first 30 postnatal days in 16 neonates with clinical, electrocardiographic and echocardiographic features of transient myocardial ischemia. These common laboratory tests, requested usually as an aid to diagnosis and surveillance of myocardial damage both in the adult and infant age groups, do not seem to have any value in the perinatal period compared to established reference values of healthy or asphyxiated controls.