bluuebunny/crossref_metadata_2025 huggingface dataset:
Ontogenic Studies of Intestinal Lactate Dehydrogenase Isozymes in the Hamster
Authors: Walden Ramsey , Schiller Carol M.
Published: September 2009

Our study of the developing small intestine presents a detailed report of the catalytic, isozymic and kinetic properties of lactate dehydrogenase. These results allow for a better understanding of the properties of this intestinal enzyme during development as well as relating these properties to the changing metabolic roles of this tissue during development.
Glycogen Content in Subcutaneous Adipose Tissue of Newborns of Different Birth Weights in the First Week of Life
Authors: Přibylová H. , Rážová M. , Vondráček J.
Published: September 2009

The glycogen content of the subcutaneous adipose tissue was examined in 164 newborns of different birth weights. It amounted to 0.48 ± 0.05 mg glycogen/g wet weight on average and did not depend on the weight of the newborn, week of gestation in the 38th to 41st week of pregnancy and duration of labor. In small-for-date newborns the glycogen content per gram wet weight was equal to the eutrophic and large-for-date newborns. The amount of fat tissue and also the total glycogen content in small-for-date newborns, however, is substantially lower. The glycogen content decreases in the first hours of life. It reaches the lowest values at 24–48 h of life. This bears witness to the quick depletion of glycogen reserves of the subcutaneous adipose tissue. The different amounts of carbohydrate and fat reserves stress the importance of early nutrition in some groups of newborns, especially of low-birth-weight newborns.
The Effect of Phototherapy on Intestinal Mucosal Enzyme Activity in the Gunn Rat
Authors: Dinari Gabriel , Cohen Michael I. , McNamara Helen , Daum Fredric
Published: September 2009

Infants undergoing phototherapy may develop loose stools. Acquired lactase deficiency secondary to this treatment modality was suggested as a cause for the diarrhea. The effects of light energy directly on intestinal enzymes and indirectly through bilirubin photooxidation products were studied. Adult homozygote and heterozygote Gunn rats were treated with light for varying periods while littermate controls were kept in the dark. Intestinal lactase, sucrase and GGTP activities and serum bilirubin concentrations were determined. Jaundiced and non-jaundiced 1-week-old suckling Gunn rats were treated with light for 96 h, and intestinal lactase activity determined. No decreases in lactase, sucrase or GGTP activities were observed suggesting the reported diarrheal states following phototherapy are not related to light energy or photooxidation products.
Growth and Development of the Neonatal Rat: Particular Vulnerability of Males to Disadvantageous Conditions during Rearing
Authors: Crutchfield Floy L. , Dratman Mary B.
Published: September 2009

Rat pups were nurtured on radioactive iodine-containing milk by dams fed low-iodine (Remington) diets plus sodium 125I-iodide (Na 125I) supplements from 3 days before parturition to the time of weaning. Effects of individual features of this experimental regimen on developmental progress of the offspring were examined. Nutritional deficiencies inherent in the maternal Remington diet did not alter growth rate, if the pups were only minimally disturbed in the course of rearing. However, when combined with chronic handling stress (itself having no detectable effect on the weight gain of pups of normally fed mothers), growth retardation was noted, without evidence of hypothyroidism. Addition of Na 125I to the maternal Remington diet reduced the growth rate of non-handled animals only. The strategy of measuring post-weaning catch-up growth served to magnify latent signs of pre-weaning growth retardation and revealed that males were more susceptible than females to early dietary deficiencies, radiation and handling stresses.
Effect of α-Adrenergic Agonist and Antagonist Infusion on the Umbilical and Uterine Circulations of Pregnant Sheep
Authors: Oakes Gary K. , Ehrenkranz Richard A. , Walker Adrian M. , McLaughlin Margaret K. , Brennan Susan C. , Chez Ronald A.
Published: September 2009

The effects of the α-adrenergic agonists, norepinephrine and methoxamine, and the α-antagonist, phenoxybenzamine, on umbilical and uterine blood flows, fetal and maternal heart rates, arterial and venous pressures were examined in near-term chronic sheep preparations. Norepinephrine injection or methoxamine infusion to either fetus or ewe resulted in a respective unilateral fetal or maternal pressor response associated with bradycardia. Uterine blood flow decreased significantly with α-agonist administration to either fetus or ewe. Umbilical blood flow did not change with either, but an increase in calculated umbilical vascular resistance did occur after fetal administrations of the α-agonist. Thus, both the uterine and umbilical vascular beds are responsive to α-agonism, but maternal uteroplacental perfusion appears to be more sensitive. α-Blockade in either fetus or mother produced no significant changes in umbilical or uterine blood flows or fetal or maternal perfusion pressure suggesting that basal α-adrenergic tone is unnecessary for normal maintenance of either fetal or maternal uteroplacental circulation.
Effect of Birth and Surfactant Treatment on Phospholipid Synthesis in the Premature Rabbit
Authors: Stewart-DeHaan Jill , Metcalfe LeRoy , Harding Paul G.R. , Enhörning Göran , Possmayer Fred
Published: September 2009

The incorporation of intraperitoneally injected 3H-glycerol and 14C-palmitate into the lipids of lung, liver and brain was examined in premature rabbits (27 days gestation, term 31) both in utero and in control or surfactant-treated neonates. With the lung, there was an increased incorporation after delivery, especially with the surfactant-treated pups. The incorporation of 3H-glycerol into liver lipids was markedly reduced after birth, particularly with the nontreated controls. The liver:lung ratios of the incorporations were decreased after delivery. In all three tissues, the relative incorporations into the individual lipids were not affected to any great extent by birth or surfactant treatment. In lung, the disaturated and monoenoic species, respectively, of phosphatidylcholine accounted for the major proportion of the radioactivity. After birth there was a small increase in the labelling of the monoenoic species at the expense of the disaturated species with both control and surfactant-treated neonates. These observations support the proposal that surfactant treatment of the prematurely delivered neonate could be used prophylactically for the prevention of the respiratory distress syndrome.
Pancreatic Insulin-, Glucagon-, and Somatostatin-Positive Islet Cell Populations during the Perinatal Development of the Rat
Authors: McEvoy Robert C. , Madson Katherine L.
Published: September 2009

Pancreatic insulin-, glucagon- and somatostatin-positive islet cell volumes were quantitated morphometric ally during the developmental interval from 16 days post coitum to 10 days postnatal. There was a rapid increase in the α- and β-cell populations during late fetal life. The β-cells increased more rapidly and comprised the major portion of the islets after the 20th fetal day. After birth the rate of increase of both β- and α-cells decreased but was greater than that of the surrounding exocrine pancreas during the early period of postnatal life. This resulted in an islet cell percentage of 5–6% of the total pancreas on day 6 postnatal. δ-Cells were present before birth but increased in volume density within the islet cell after birth. The implications of these morphological data to the interpretation of physiological studies are discussed.
Pancreatic Insulin-, Glucagon-, and Somatostatin-Positive Isle Cell Populations during the Perinatal Development of the Rat
Authors: McEvoy Robert C. , Madson Katherine L.
Published: September 2009

Insulin, glucagon and somatostatin concentration were determined in the developing pancreas between 16 days post coitum and 10 days postnatal. Plasma insulin and glucagon concentrations were also measured. Pancreatic insulin content increased rapidly during the perinatal period and peaked in concentration on day 6 postnatal. Glucagon content also increased rapidly with the largest percentage increase occurring around the time of birth. The largest increase in somatostatin also occurred postnatally. Plasma insulin and glucagon concentrations were very high during the late fetal period. The insulin concentration fell immediately after birth and rose slowly toward adult levels during the remainder of the period examined. Plasma glucagon was high during the entire neonatal period. The degree of differentiation of the islet cells, as estimated by their content of specific hormone products, is discussed in relation to the changes in cell volume reported in the preceding paper.
Cerebral Metabolism during Hypoglycemia and Asphyxia in Newborn Dogs
Authors: Vannucci Robert C. , Nardis Elizabeth E. , Vannucci Susan J.
Published: September 2009

The cerebral metabolic responses to perinatal hypoglycemia (blood glucose ≤ 1 mmol/l) combined with asphyxia were studied in paralyzed, lightly anesthetized newborn dogs. No major differences in heart rate, blood pressure or arterial acid-base balance between control and hypoglycemic animals occurred either prior to or during asphyxia. The electroencephalogram, unaltered by hypoglycemia alone, became isoelectric at the same intervals in both groups following respiratory arrest. Intravenous carbon black infusion at 5 min of asphyxia demonstrated no relationship between blood glucose level and cerebral perfusion (p > 0.05), whereas a positive correlation did exist between systemic blood pressure and cerebral perfusion (p < 0.01). During asphyxia, anaerobic glycolysis in brain was less enhanced in hypoglycemic dogs, resulting in a more rapid exhaustion of high-energy phosphate reserves (phosphocreatine, ATP and ADP). Thus, the cerebral metabolic responses to asphyxia superimposed upon hypoglycemia were the direct consequence of insufficient cerebral glucose stores coupled with deficient circulating glucose to brain. These metabolic disturbances were no more the result of cerebral ischemia than that which occurs during asphyxia alone. The findings also suggest that systemic physiological monitoring may be an inadequate means of appraising cerebral homeostasis during combined hypoglycemia and hypoxia.
Effects of Perinatal Exposure to Benzo(a)pyrene on the Aryl Hydrocarbon Hydroxylase System of Adult Rat Liver
Authors: Herd Jan Earl , Greene Frank E.
Published: September 2009

Early exposure to benzo(a)pyrene, B(a)P, produces long-lasting effects on the cytochrome P-450 dependent monooxygenase system of rat liver microsomes. Adult male offspring of rats given B(a)P, 20 mg/kg i.p. during late pregnancy, showed either a small but significant depression of basal aryl hydrocarbon hydroxylase activity or an impaired induction response to B(a)P. Few significant changes were found in the relative amounts of the individual metabolites formed from B(a)P by microsomes from perinatally exposed rats, either in the basal or B(a)P-induced state. In addition, perinatal exposure to B(a)P tended to decrease the binding of B(a)P to calf thymus DNA in in vitro incubations.
Effect of Intrauterine Growth Retardation on the Activities of Fetal Intestinal Enzymes in Rats
Authors: Lebenthal Emanuel , Nitzan Menachem , Lee P.C. , Chrzanowski Barbara L. , Krasner Joseph
Published: September 2009

The activities of maltase, lactase, alkaline phosphatase and enterokinase were followed in the small intestine of rats during prenatal development. These enzymes were detectable only after the 17th day of gestation. Furthermore, each enzyme exhibited a different pattern of prenatal presence. Maltase activity appeared first (day 18), followed by lactase and alkaline phosphatase (day 19) and then enterokinase (day 20). Except for enterokinase, all of the enzymes attained a level of activity close to the newborn levels at the final day of gestation. Induced intrauterine growth retardation during the 3rd trimester led to a decrease in intestinal weight proportional to the reduction of body weight. The decrease in size of the small intestine was caused by a reduction in cell number rather than cell size. Induced intrauterine growth retardation also resulted in a selective reduction in the specific activities of lactase and alkaline phosphatase, but not of enterokinase and maltase. These results suggest that reduction in maternofetal blood flow in the 3rd trimester of gestation will cause a selective decrease in some brush border enzymes (lactase and alkaline phosphatase) but does not affect others (maltase and enterokinase).
Lipids and Lipoproteins in Maternal and Fetus Plasma in the Rat
Authors: Argiles J. , Herrera E.
Published: September 2009

Plasma lipidic components appear augmented in 19- and 21-day pregnant rats compared with virgin controls, the greatest effect being in triglycerides, corresponding to the augmented proportion of plasma very low density lipoproteins (VLDL). The plasma lipidic components in fetuses of 19 and 21 days are lower than in their mothers, the greatest decrease occurring in triglycerides. In the plasma of 19-day fetuses, there is only one lipoprotein electrophoretic band which corresponds to the Β-lipoproteins of adults (low density lipoproteins, LDL) according to its mobility and floating characteristics, while in the fetus of 21 days there are also pre-Β-lipoproteins (VLDL). In the 1- and 5-day-old newborns, the four main lipoprotein fractions are already present as in the adults. The late appearance of VLDL and the lack of high density lipoproteins in the rat fetus determine various specific metabolic characteristics.
Oxytocin Concentrations during the Neonatal Period
Authors: Leake Rosemary D. , Weitzman Richard E. , Fisher Delbert A.
Published: September 2009

Plasma oxytocin levels in the umbilical artery (UA) exceeded umbilical venous levels in newborn infants delivered by cesarean section (without maternal labor) (p < 0.05) and following labor (NS). There was an initial rapid decrease in oxytocin concentration from UA levels to those in peripheral venous blood by 30 min of age. Plasma oxytocin levels for breast-fed and formula-fed infants remained elevated over adult basal levels (1.7 ± 0.3 μU/ml) throughout the 4-day study period. Mean oxytocin concentration measured in breast milk from 10 mothers 2–4 days following vaginal delivery was 10.0 ± 1.4 μU/ml. The stimulus for fetal and neonatal oxytocin secretion remains obscure, but continues beyond the period of birth.
Brown Fat Thermoregulation in Developing Hamsters (Mesocricetus auratus): a GDP-Binding Study
Authors: Sundin U. , Herron D. , Cannon B.
Published: September 2009

The thermogenic capacity of brown fat from neonatal and developing hamsters was investigated. The method used was to measure the capacity of brown fat mitochondria to bind externally added guanosine diphosphate (GDP). This gives an estimate of the number of proton-conducting channels and hence the capacity of heat production in the mitochondria. At an age of 12 days post-partum the GDP-binding capacity is low: 0.14 nmol GDP/mg mitochondrial protein. Thereafter the capacity shows a steady increase up to 0.54 nmol/mg at 20 days. The peak is followed by a slow decrease down to the level of the adult hamster: 0.32 nmol/mg. This pattern of brown fat development is strikingly similar to reports on the development of oxygen consumption measured on whole animals or on the ability to maintain a constant body temperature when the ambient temperature is lowered. The calorigenic response to injected noradrenaline also follows this pattern. It is therefore justified to suggest that brown fat is a major effector of regulative metabolic heat production in the developing hamster.
An Improved Technique for Perfusion of the Guinea Pig Placenta in situ Giving Viable Conditions Demonstrated by Placental Transport of Amino Acids (L- and D-Alanine)
Authors: Kihlström J. , Kihlström J.E.
Published: September 2009

An improved technique for perfusing the fetal guinea pig placenta in situ is described. The result shows linear pressure-flow relations in the range of 15–50 mm Hg, assumed to be physiological. The preparation shows impermeability for trypan blue. The placental transfer is stereoselective for L-alanine compared with D-alanine. This transfer is ouabain-sensitive, and proceeds against a concentration gradient.
Fetal Rat Adrenal Gland Steroidogenesis in vitro in Prolonged Pregnancy
Authors: Klepac R.
Published: September 2009

Progesterone, injected into pregnant rats on the last days of pregnancy, prolonged pregnancy and prevented parturition. The fetuses from mothers whose pregnancies were prolonged have greater body and adrenal weights on days 23 and 24 of gestation as compared with 1- and 2-day-old rats. The adrenal glands of fetuses and neonatal rats converted in vitro 4-14C-progesterone to 11-deoxycorticosterone (DOC), corticosterone (B), 18-hydroxy-11-deoxycorticosterone (18-OH-DOC), 18-hydroxy-corticosterone (18-OH-B) and aldosterone. The fetal adrenal glands on the 23rd and 24th day of pregnancy synthesized in vitro less DOC, corticosterone and 18-OH-DOC than the adrenal glands of intact neonatal rats. These results demonstrated that progesterone in prolonged pregnancy inhibited enzymes of steroid hydroxylation which converted progesterone to DOC, corticosterone and 18-OH-DOC in fetal rat adrenal glands.
Effects of Maternal Caffeine Ingestion on Neonatal Growth in Rats
Authors: Dunlop Marjorie , Court John M.
Published: September 2009

When caffeine (1,3,7-trimethylxanthine) was introduced into the diet of rats throughout pregnancy and lactation at levels of consumption of 10 mg/kg/day, offspring of successive pregnancies showed growth reductions. This finding was not accompanied by teratogenic effects. However, following four pregnancies severely reduced offspring growth and neonatal mortality was demonstrated. The birthweights of these offspring were 72.5% of control. This study mimicked the mode of intake and quantities of caffeine consumed in many societies.
Metabolic Responses to Severe Perinatal Asphyxia in Term Newborn Infants with Particular Reference to the Changes in Plasma Free Amino Acids
Authors: Schultz K. , Soltész G. , Mestyán J.
Published: September 2009

Blood glucose, blood lactate, plasma FFA, plasma α-amino nitrogen and 17 individual amino acids were determined on admission, and at 24 and 48 h after admission in severely asphyxiated term newborn infants. The blood glucose value was widely scattered and the plasma FFA level was low on admission. The total free plasma amino acid content correlated closely with the severity of asphyxia-induced lactic acidosis. Among the 17 amino acids determined, 11 turned out to be significantly increased. The increase of plasma free amino acids might be toxic for the central nervous system, therefore parenteral feeding of asphyxiated neonates with amino acid mixtures can be dangerous.
Sequential Observation of Changes in Thyroxine, Triiodothyronine and Reverse Triiodothyronine during the Postnatal Adaptation of the Pig
Authors: Ślebodziński A.B. , Nowak G. , Zamysłowska H.
Published: September 2009

Principal serum iodothyronines, T4, T3 and rT3, have been simultaneously measured by a specific radioimmunoassay in piglets kept for sequential observation with the mother from 1 to 21 days of age. During several hours postnatally, a high concentration of the hormone was noted as a result of an enhanced secretory activity of the thyroid gland. Later, a progressive decrease with a nadir at about day 3 was observed, followed by a second rise in the hormone level. Changes in T3 and rT3 levels from birth to the end of the 1st week, paralleled those for T4. The T3:rT3 ratio of about 2 during the 1st week fell to about 1.5 during the 3rd week as a result of the progressive increase in rT3 and decrease in T3 concentrations. The T4:rT3 ratio fell with the progressing age to the level observed in post-weaned pigs. At birth, the newborn pig seems to possess a low capability of 5-deiodinase enzyme system thus the converting enzymes first work towards T4–T3 conversion while T4–rT3-converting ability progressively increases with age. The role of this variability for the neonatal thermogenic stability is discussed.
Comparative in vivo and in vitro Effect of Mono- and Disaccharides on Intestinal Brush Border Enzyme Activities in Suckling Rats
Authors: Raul Francis , Kedinger Michèle , Simon Patricia M. , Grenier Jacques F. , Haffen Katy
Published: September 2009

Suckling rats were bottle fed during 48 h with a basic diet enriched with different mono- or disaccharides. In parallel, explants of intestinal mucosa were cultured in vitro for 48 h in the presence or in the absence of a synthetic glucocorticoid (dexamethasone) and with or without different carbohydrates. In both studies, enzyme activities were assayed on purified brush border membranes. From these combined in vivo and in vitro investigations it appeared that (1) there is a highly specific stimulation of mono- and disaccharides on the corresponding brush border disaccharidases: glucose, fructose, sucrose on sucrase and maltase activities, fructose being generally the most potent activator. Other brush border enzymes were not modified by the dietary carbohydrates. (2) These sugar-mediated effects were obtained only in the presence of glucocorticoids. This hormone alone induced the appearance of a slight sucrase activity and provoked a stimulation of maltase activity. The results show clearly that glucocorticoids are necessary to induce sucrase activity, but that the level of this activity is under the strict dependence of the dietary carbohydrates.
Phenytoin Administration to Pregnant Mice: a Mutagenic Action?
Authors: Petter Claude , Lombard Marie-Noelle , Ehrensperger Maud
Published: September 2009

Phenytoin orally administered to pregnant NMRI mice results in limb haemorrhages, necrosis, and in most cases in limb amputations in the offspring. By mating these offspring without any treatment, the same type of abnormalities appeared throughout seven successive generations. In the second and third generations, other malformations, such as haemorrhages of the eyelids, and genitourinary defects were observed. These findings raise the question of the mutagenic role of phenytoin. Phenytoin is a drug of considerable medical use, but very little is known about the various possible intermediate steps involved in its action.
Skeletal Muscle Development in the Fetal Pig after Decapitation in utero
Authors: Campion D.R. , Hausman G.J. , Richardson R.L..
Published: September 2009

The effect of fetal decapitation on skeletal muscle growth and development in utero was studied in the pig. Pig fetuses were decapitated at 45 days of gestation and the peroneus longus muscle was analyzed at 110 days of gestation. Muscle wet weight, length, minimum fiber diameter, DNA, RNA, protein content, and incidence of muscle fiber nuclei and satellite cell nuclei were determined in the decapitated fetus and in sham-decapitated control fetuses. Decapitation did not significantly influence (p > 0.05) any of the traits measured. Muscle and satellite cell ultrastructure was not altered by decapitation. Therefore, an intact brain and hypothalamic-hypophyseal axis are not critical to growth and development of fetal pig skeletal muscle as measured in this study.
Relationship of Mitochondrial Phosphoenolpyruvate Carboxykinase to Neonatal Gluconeogenesis
Authors: Parameswaran Madangarli , Arinze Ifeanyi J.
Published: September 2009

Gluconeogenesis from (U-14C)-lactate occurred in hepatocytes prepared from term fetuses which lack cytosolic phosphoenolpyruvate carboxykinase and was almost completely inhibited by 3-mercaptopicolinate but was relatively insensitive to amino-oxyacetate. 12 h after birth when up to 32% of the total hepatic phosphoenolpyruvate carboxykinase activity was detectable in the cytosol, glucose synthesis was increased 4.4-fold in hepatocytes from fasted neonates and was partially (37%) sensitive to amino-oxyacetate. In livers of fasted 24-hour-old neonates total phosphoenolpyruvate carboxykinase activity was distributed between the mitochondria and the cytosol in the ratio of 60:40. In hepatocytes prepared from such animals, amino-oxyacetate inhibited glucose synthesis by about 56%, suggesting that up to half of the carbon flow from lactate to glucose was via the formation of phosphoenolpyruvate in the mitochondria. These studies indicate an important role for mitochondrial phosphoenolpyruvate carboxykinase in neonatal gluconeogenesis.
Somatic Growth and Brain Development
Authors: Meberg Alf
Published: September 2009

Groups of female mice were starved or exposed to hypobaric hypoxia during pregnancy. A significantly lower weight gain during pregnancy occurred in the mothers starved or exposed to hypoxia compared to controls. Hypoxia also decreased maternal food intake. Therefore, the hypoxic groups included a combination of hypoxia and starvation. Body weight, brain weight, brain DNA (deoxyribonucleic acid) and total protein were investigated in the offspring at birth and at 20 and 70 days of age. Starvation and hypoxia impaired fetal growth, with reduction in body weight, brain weight, brain cell number (DNA content) and brain total protein content in a dose-related manner. In the most severely starved fetuses brain cell size (brain weight/DNA and total protein/DNA) was also reduced. Long-term effects were observed with lower body weight, brain weight and brain DNA content at adult age in the most severely malnourished and hypoxic offspring. Catch-up growth took place after a more moderate starvation and hypoxic exposure. It is concluded that intrauterine malnutrition interferes with fetal cellular mitotic rate. This may give rise to growth-retarded fetuses because of a decreased cell number. Depending on the degree of malnutrition a cell deficit may persist at adult age. Intrauterine hypoxia may aggravate these effects of fetal starvation.
Lipids in Forehead Vernix from Newborn Infants
Authors: Wysocki S.J. , Grauaug A. , O’Neill G. , Hähnel R.
Published: September 2009

Neutral lipids in forehead vernix from newborn infants of various gestations were analysed by gas chromatography. Vernix collected from pre-term ( < 37 weeks) infants differed markedly from that collected from near-term (≥ 37 weeks) infants. The principle difference was an increase in the content of squalene relative to other lipids in vernix from near-term infants. This change indicated a surge in fetal sebaceous gland function at about 37 weeks gestation.
Development of Taurine Metabolism in Beagle Pups: Effects of Taurine-Free Total Parenteral Nutrition
Authors: Malloy Michael H. , Rassin David K. , Gaull Gerald E. , Heird William C.
Published: September 2009

In beagle pups (from 5 to 84 days of age), plasma taurine concentration decreased between 5 and 21 days of age with no change thereafter; cerebral taurine concentration decreased throughout the period of study but cerebral taurine content increased between 5 and 21 days of age; hepatic taurine content (but not concentration) increased throughout. Both hepatic cysteinesulfinic acid decarboxylase (CSAD) activity and the concentration of taurine-conjugated bile acids of gallbladder bile increased during the period of study. Plasma and cerebral taurine pools were not affected by taurine-free total parenteral nutrition (TPN). Hepatic taurine content also was not affected, but taurine concentration decreased; however, this change resulted from an increase in hepatic size. Hepatic CSAD activity of animals that received TPN was greater than that of 35-day control animals while the concentration of taurine-conjugated bile acids in the gallbladder bile was less. Although plasma taurine concentration was not affected by intravenous glucose therapy, both the hepatic taurine concentration and content of these animals were less than those of 35-day control animals. Cerebral taurine concentration and content of these animals, on the other hand, were greater. Hepatic CSAD activity of the animals that received only intravenous glucose was similar to that of controls, but the taurine-conjugated bile acid concentration in the gallbladder bile, like that of animals that received TPN, was less than that observed in 35-day control animals.
Chemical Changes in Human Skeletal Muscle during Fetal Development
Authors: Brans Yves W. , Shannon Donna L.
Published: September 2009

Skeletal muscle samples obtained from 6 nonmacerated stillborn fetuses and 18 liveborn neonates who died within 24 h of birth were analyzed. Gestational ages ranged from 19 to 44 weeks. 17 neonates were normally grown (NG) and 7 were intrauterine growth retarded (IGR). Chemical components were expressed in milliliters or grams per lOOg of tissue. As gestation progressed, total water (TW) and extracellular water (ECW) contents decreased, intracellular water (ICW) content and nitrogen content remained stable, and intracellular/total water ratio (ICW/TW) increased. Fat content was negligible throughout gestation. Compared to their NG peers, IGR neonates had muscle with decreased ECW and increased ICW/TW, whereas TW, ICW and nitrogen contents were similar. These preliminary data provide a basis for further studies of muscle composition and for discussion of existing hypotheses on the effect of fetal growth retardation upon body composition.
Postnatal Proximodistal Development of the Small Bowel Mucosal Mass in Growing Rats
Authors: Buts Jean-Paul , de Meyer Roger
Published: September 2009

The development of the duodenal, jejunal, and ileal mucosal mass was studied in five groups of rats killed at different ages during growth. After sacrifice, the small bowel was removed from the pylorus through the ileocecal valve, measured and divided into three equal segments (A, B, C). Gut weight, mucosal weight, DNA, protein, and sucrase activity were determined in each segment. For each segment, results of all mucosal mass parameters expressed per centimeter of gut length markedly increased during weaning (15–30 days), and at 40 days of age they were similar to those obtained in adult animals. A proximal to distal gradient of gut weight was present at birth and increased during lactation. However, the proximodistal gradients of mucosal weight and mucosal DNA per centimeter of length remained constant in all groups studied. The intestinal gradient of sucrase activity was absent at birth and in lactating rats (17 days), but was similar in rats of 30, 40, and 100 days of age. It is concluded that mucosal hyperplasia which occurs in rats at weaning equally develops in the proximal, mid, and distal small bowel.
Development of γ-Glutamyltranspeptidase Activity in Mouse Small Intestine: Influence of Cortisone and Thyroxine
Authors: Ménard D. , Malo C. , Caívert R.
Published: September 2009

The fetal and postnatal development of γ-glutamyltranspeptidase (γ-GT) activity has been examined in the different parts of the mouse small intestine. At 17 days of gestation, γ-GT is present in all intestinal thirds and a decreasing gradient of activity from the proximal to the distal segments is already established. From 17 days of gestation up to 5 days after birth, a dramatic fall of activity is observed in all segments. γ-GT activity reaches adult level before weaning in the proximal segment while it increases only during the 3rd postnatal week in the middle and distal intestinal segments. Daily administration of cortisone acetate (25 μg/g b.w./day) for 3 days to 8-day-old mice elicits a premature increase of γ-GT activity in all intestinal thirds, the maximal increase being observed in the proximal segment. On the other hand, thyroxine (1 μg/g b.w./day) has no or little effect on the normal development of γ-GT activity.
Cyclic 3′,5′-Adenosine Monophosphate in Umbilical Cord Blood of the Newborn Infant: Relation to Fetal Stress and Plasma Catecholamines
Authors: Bistoletti P. , Fredholm B.B. , Lagercrantz H.
Published: September 2009

Cyclic 3′,5′-adenosine monophosphate (cyclic AMP) was analyzed in the venous blood of the mothers and in the umbilical vein and artery of the infant at birth. In general, higher cyclic AMP levels were found in the umbilical vein than in the artery which were similar to the maternal values. Asphyxia and vacuum extraction were associated with significantly higher cyclic AMP levels, while the concentration was lower after elective cesarean sections than after uncomplicated vertex deliveries. The cyclic AMP concentrations were inversely correlated to pH and directly related to the catecholamine concentrations. The origin and possible significance of cyclic AMP in umbilical cord plasma is discussed.
Effect of Lung Inflation on Ventilation and Various Phases of the Respiratory Cycle in Preterm Infants
Authors: Sankaran Koravangattu , Leahy Fergus N. , Gates Don , MacCallum Marilyn , Rigatto Henrique
Published: September 2009

The effect of sudden and sustained lung inflation on inspiratory time (Ti), expiratory time (Te) and duration of apnea, as a translation of the Hering-Breuer reflex, has not been systematically analyzed in preterm infants. To examine such effects, 10 infants (body weight 1,550 ± 110 g; gestational age 31 ± 1 weeks) were studied. Lung inflation was obtained by applying negative pressure around the chest using a negative pressure incubator. After a control period, lung volume functional residual capacity was increased by an average of 14, 23, 34 and 53%. During lung inflation, Ti, Te, total respiratory cycle duration, incidence and duration of apnea increased. Minute ventilation decreased due to a decrease in frequency. Tidal volume decreased but not significantly. Inspiratory and expiratory flows decreased. These results (1) confirm the presence of the Hering-Breuer reflex in preterm infants, as reflected by increased Te and appearance of apnea during lung inflation; and (2) show that contrary to expectations, Ti increased significantly with lung inflation.
Lung Tissue Progesterone in the Human Fetus and Neonate
Authors: Joensuu H. , Kero P. , Pulkkinen M.O.
Published: September 2009

During fetal life human lungs have a high progesterone concentration (average 380 ng/g at 14 weeks of gestation and 635 ng/g at 32 weeks). At 30 h of age, this concentration had decreased to 185 ng/g. During the first 72 h of life, some infants with respiratory distress syndrome (RDS) had a higher amount of progesterone in their lungs than infants with diseases other than RDS. In newborns with RDS, serum transcortin (binding progesterone) was close to the normal value, but serum progesterone concentration 57% below normal. The hypothesis that, in addition to surfactant, lung tissue smooth muscle (regulated among other things by progesterone and prostaglandins) may control lung function at birth is strengthened by the fact that RDS can be provoked by progesterone in the rabbit and that fatty acids and prostaglandins are abnormal in human RDS.
Pituitary Gonadotrophins in Fetal and Neonatal Rabbits
Authors: YoungLai E.V. , Pan C.-C. , Bhavnani B.R.
Published: September 2009

The pituitary gonadotrophins luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were found to be higher in female rabbit fetuses from day 25 to day 32 of pregnancy. No difference was observed in pituitary gonadotrophins or serum LH in the neonatal males and females on days, 1, 6 and 13. Serum FSH concentrations were significantly higher in female than in male neonates. It is concluded that the rabbit fetal pituitary is capable of synthesizing gonadotrophins from day 25 of gestation.
The Comparative Hemodynamic Effects of Propranolol in Chronically Instrumented Puppies and Adult Dogs
Authors: Driscoll David J. , Fukushige Junichiro , Lewis Robert M. , Hartley Craig J. , Entman Mark J.
Published: September 2009

To determine if there are age-related changes in response to propranolol, we studied the hemodynamic effects of this β-adrenergic-blocking agent in 19 awake chronically instrumented puppies and compared the response to that of 9 awake chronically instrumented adult dogs. Following intravenous administration of 1 mg/kg propranolol, heart rate, cardiac output, stroke volume, systemic arterial mean blood pressure and systemic vascular resistance were reduced similarly in all age groups of animals. However, puppies were more sensitive to the β-adrenergic-blocking effect of propranolol than adult dogs when stressed with isoproterenol.
Levels of Serum Protease Inhibitors during Fetal and Postnatal Development of the Pig
Authors: Weström B.R. , Karlsson B.W. , Svendsen J.
Published: September 2009

Using electroimmunoassay the levels of the individual protease inhibitors, α2- macrogloulin f, α2-macroglobulin s, inter-α-trypsin inhibitor, α1-protease inhibitor and α2-antitrypsin were studied in the serum and the amniotic fluid during the fetal and postnatal development of the pig. High concentrations, far above the adult ones, of α2-antitrypsin and especially α1 -protease inhibitor, were observed in serum during the fetal period, contrary to the low levels of the α-macroglobulins. Thus, the development of these inhibitors in pigs differs markedly from the development in the human fetus. After birth, when the piglet had begun to suckle, the levels of all the inhibitors, except that of α2-macroglobulin s, decreased. This can partly be explained by the dilution of the serum due to the increase in plasma volume and losses via the urine. The sharp increase of α2-macroglobulin s during the first days after birth probably represented an extensive synthesis. All the inhibitors had attained their adult levels at about 35 days after birth. All the protease inhibitors studied, except for α1-macroglobulin s, were found in the amniotic fluid, and reached the maximal levels at about 55–66 days of gestation. These inhibitors appeared to have fetal origin. The physiological significance of the protease inhibitors during fetal and neonatal development of the pig is discussed. It is suggested that the function of these inhibitors might be to protect the cells and tissues from proteolytic attack by the formation of inactive enzyme/inhibitor complexes.
9-Methyl Pteroylglutamic Acid, a Synthetic Analogue of Folic Acid: Its Effects on Hexosamine Levels in Fetal Rat Limbs and Other Fetal Tissues
Authors: Schmidt Richard R. , Abbott Patricia K. , Cotler Jerome M.
Published: September 2009

Pregnant rats were administered the teratogen and synthetic analogue of folic acid, 9-methyl pteroylglutamic acid, on the 11th day of gestation and placed on a semi-synthetic diet containing the antagonist but lacking the vitamin until the 14th gestational day. This transitory maternal folic acid deficiency results in multiple congenital skeletal malformations. Control animals were administered a folic acid-supplemented regimen. Hexosamine levels were measured in fetal tissues, i.e. limbs, livers, and yolk sacs, in order to monitor the accumulation of a primary constituent of the extracellular matrix, i.e. glycosaminoglycans. Fetal tissues were obtained for hexosamine analysis on the 16th and 18th days of gestation. The teratogenic and transitory folic acid-deficient regimen resulted in (1) a significant reduction in the accumulation of hexosamine in fetal limbs by the 16th day of gestation, and (2) a significant increase in the accumulation of hexosamine in fetal livers by the 16th day of gestation. The regimen was observed to have had no effect on hexosamine accumulation by the yolk sac. Furthermore, no significant effect on hexosamine accumulation from the 16th to the 18th day of gestation was observed in any of the tissues studied.
Fetal and Early Postnatal Development of Adenylate Cyclase and Cyclic AMP Phosphodiesterase Activities in Rat Brain
Authors: Salinas Matilde , Galán Almudena , Herrera Emilio
Published: September 2009

Brain cyclic AMP metabolism was studied in rat offspring at 17, 19 and 21 days of intrauterine life and 0, 1 and 4 postnatal days. Wet weight and protein and DNA and RNA concentrations in brain increased in parallel with body weight until the 4th postnatal day although during the perinatal phase some of these parameters suffered a manifest temporal retardation. In the brain, similar qualitative changes were observed in both adenylate cyclase and high Km cyclic AMP phosphodiesterase activity while the low Km enzyme showed a rise from 17-day fetuses to those of 19 days with no further changes. The increase in cyclic AMP concentration was very mild and the values found in the 21 -day fetuses were already similar to those in adults. In the mother’s brain a significant reduction in adenylate cyclase activity appeared at 19 and 21 days of gestation. The retardation in the ontogenic development of cyclic AMP metabolism during the perinatal phase in offspring is probably a consequence of their specific metabolic situation while in the mother it may be the result of its endocrine preparation for parturition.
Plasma Catecholamine Responses to Hypoxemia in Fetal Lambs
Authors: Lewis Alan B. , Evans William N. , Sischo William
Published: September 2009

The plasma catecholamine responses to hypoxemia were evaluated in 10 chronically catheterized fetal lambs in utero from 0.77 gestation to term using a highly sensitive radioenzymatic assay. Hypoxemia was produced by gradual constriction of the umbilical cord by an implanted cuff occluder. Fetal carotid arterial PO2 fell from 23 to 12 torr and was accompanied by an exponential increase in catecholamine concentration. Plasma norepinephrine (NE) increased from 256 ± 31 to 1,888 ± 384 pg/ml while epinephrine rose from 24 ± 5 to 1,159 ± 433 pg/ml. Fetal arterial PO2 returned to normal within 1 min of deflating the cuff occluder. Simultaneously, NE and epinephrine levels declined rapidly but, nevertheless, remained mildly elevated compared to controls. There was no maturational change in baseline NE levels during the last quarter of gestation, whereas epinephrine was significantly higher after 125 days than between 115 and 125 days (37 ± 7 vs. 16 ± 6 pg/ml, p < 0.05). However, maturation had no significant effect upon the magnitude of the epinephrine or NE response to hypoxemia. In conclusion, the late gestation fetal lamb is capable of manifesting a profound catecholamine response to hypoxemia which appears to play a major role in the compensatory cardiovascular adjustment to severe stress.
Influence of a Low Protein Diet on Salicylate-Induced Damage in Mice
Authors: Eriksson Margareta , Larsson Sune
Published: September 2009

The influence of a low protein diet (8%) during pregnancy on the teratogenic potential of sodium salicylate was studied in NMRI mice. Sodium salicylate was given intramuscularly as a single dose of 250 or 500 mg/kg on gestation day 9 or 17. Reduced fetal weight was the only adverse effect of the low protein diet. Following the teratogenic dose of 500 mg/kg, more skeletal malformations were found in fetuses of deficient mothers than of those on a standard diet. An increased incidence of fetal death was demonstrated on gestation day 17 even at the subteratogenic dose of 250 mg/kg.
Plasma Corticosterone during Perinatal Period in Postmature Rats
Authors: Roudier M. , Portha B. , Picon L.
Published: September 2009

In the fetal rat, plasma corticosterone concentration (PCC) decreases dramatically on the 20th day of gestation and remains low until birth even if the parturition is delayed until 23.5 days postcoitus. In the normal term newborn, there is an increase of PCC in the lsth after birth. In postmature newborn rats this increase is not present but PCC can be increased towards normal term values if the adrenal cortex is stimulated with cosyntropin or lysine-vasopressin. This suggests that the lack of elevation of PCC in the postmature newborn is not due to the lack of responsiveness of the adrenal cortex but rather to an impairment of the hypophyseal stimulation. The absence of PCC elevation at birth could contribute to the metabolic disorders observed in the postmature newborn rat.
Uptake and Retention of Sex Steroids by the Neonatal Rat Adrenal Gland
Authors: Simmons Emmet , Bronsky Peter T. , Woodard Eric J.
Published: September 2009

The uptake of radioactivity in the adrenal glands of 5-day-old male and female rats was examined 2 h following injection of radiolabeled testosterone, R1881, diethylstilbestrol, or estradiol. The adrenals of both sexes had higher levels of radioactivity than blood after testosterone or synthetic androgen (R1881) injection. The adrenals of neither sex showed any significant accumulation of radioactivity, following 3H-estradiol injection. When, however, cytosol prepared from neonatal adrenal glands was incubated with 2 nM 3H-estradiol, and the incubate subjected to column chromatography on Sephadex G-100, radioactivity was eluted with the void volume; this peak was absent with the addition of 100-fold unlabeled estradiol to the incubation. The possible role of α-fetoprotein in preventing the in vivo uptake and retention of 17β-estradiol is discussed since 3H-diethylstilbestrol, an estrogen which has low affinity for this protein, was retained by the adrenals of male rats. It is concluded that estrogens or androgens can have a direct effect on the neonatal adrenal gland.
Changes in the Cellular Environment of Differentiating Type II Pneumocytes
Authors: Marin L. , Dameron F. , Relier J.P.
Published: September 2009

The changes occurring in the cellular environment of differentiating type II pneumocytes have been studied using the perinatal rat lung as a model. The various cellular types in contact with type II pneumocytes during late fetal and neonatal period have been identified. The percentage of type II cells in contact with each cellular type has been calculated, and the extent of the contact areas has been measured. During the studied period, type II pneumocytes are in contact with other epithelial cells (type I or type II pneumocytes) on their lateral sides. On their basal side, they are facing lipid loaded fibroblasts and endothelial cells of the capillary walls. The results of the measurements show that from day 19 of gestation on, the contact area between type II pneumocytes and other epithelial cells decreases, whereas the luminal and especially the basal sides increase. On day 19, the whole basal side of type II pneumocytes is lined by lipofibroblasts. As maturation proceeds thereafter, contact is gradually made with endothelial cells. But the extent of these contacts remains always smaller than the contacts between type II pneumocytes and lipofibroblasts. The developmental significance of these results is discussed.
Accurate Measurement of Cerebral Metabolism in the Conscious, Unrestrained Neonatal Piglet
Authors: Wootton R. , Flecknell P.A. , John Muriel
Published: September 2009

A technique has been developed for the accurate and precise measurement of cerebral blood flow in the conscious, unrestrained neonatal piglet. Repeat determinations under conditions in which the animals could observe the experimenters showed that there was a significant fall in cerebral perfusion rate between first and second measurement, amounting to about 15 ml/min/100 g. This systematic error was subsequently avoided by use of screens and the reproducibility of the technique was then estimated to be 5.9 ml/min/100g (SD). When 5 animals were subjected to moderate stress by handling, there was a significant (p < 0.001) increase in cerebral perfusion rate to a mean value of 172.6 ± 35.0 ml/min/100 g (± SEM). Mean resting cerebral perfusion rate in 18 normal animals was 65.6 ± 4.6 ml/min/100 g (± SEM), which is similar to that reported in the conscious neonates of other species including man.
Onset of a Feedback Inhibition by Testosterone in Male Rat Fetuses
Authors: Naessany Saed , Picon Régine
Published: September 2009

A significant decrease in fetal testicular testosterone content was observed on day 20 of gestation 38 h after testosterone propionate injections into pregnant rats. Increased plasma testosterone, induced by androgen injections, was also followed by a significant fall in testicular testosterone content on day 19 without any modification in the weight of the testis. As no effects on the testosterone content were observed on days 17 and 18, it appears that the onset of a negative feedback loop becomes effective from the 19th day of gestation.