bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of Preestablished Criteria for Deciding on Extubation in the Very Low Birthweight Newborn
Authors: Huon C. , Moriette G. , Mussat P. , Parat S. , Relier J.P.
Published: October 2009

The duration of mechanical ventilation (MV) in very low birthweight infants can sometimes be very prolonged, even in the absence of any respiratory disease. To avoid this, we have developed a double-blind study protocol of the concomitant use of caffeine and doxapram or caffeine and placebo as an aid to early weaning from MV. This protocol necessitated the definition of very precise ventilatory criteria for extubation. Even before the double-blind code has been broken, we can note that the duration of ventilation was very significantly reduced (p < 0.001) from 27.5 days (median; range 1–99) in infants of the retrospective study group to 4 days (median: range 1–34) in the prospective study group (extubation according to strict criteria). This reduction in duration of MV cannot be explained by a difference in the severity of the initial pathology, or by the treatment of some of the infants with doxapram (the difference would not be so marked), but, probably, to the definition of strict criteria concerning extubation.
Comparative Disposition Kinetics of 111ln-Labeled Group B Streptococcus and Neutrophils during Onset of Sepsis-Induced Pulmonary Hypertension
Authors: Aziz Shewan M. , Sandefer Erik P. , Pauly Thomas H. , Gillespie Mark N.
Published: October 2009

Little is known of the time course by which intravascular group B streptococcus (GBS) distributes into the infant lung, though the prompt onset of pulmonary hypertension in GBS-infected animals suggests that bacteria interact initially with a resident lung cell or that they promote rapid pulmonary influx of circulating effector cells. Using external gamma scintigraphy to monitor the organ-specific disposition kinetics of 111ln-oxine-labeled GBS in anesthetized piglets, we found that 80% of the infused bacteria rapidly distributed into the lung and that pulmonary bacterial uptake exhibited a close temporal relationship with the onset of pulmonary hypertension. Companion studies demonstrated that the extent of pulmonary 111In-neutrophil sequestration was unaffected by GBS, although a neutrophil secretagogue, phorbol myristate acetate, caused rapid pulmonary neutrophil uptake. These observations support the hypothesis that the onset of pulmonary hypertension in GBS sepsis can be attributed to interactions between the bacteria and resident lung cells.
Surfactant Improves Lung Function and Morphology in Newborn Rabbits with Meconium Aspiration
Authors: Sun Bo , Curstedt Tore , Song Guo-Wei , Robertson Bengt
Published: October 2009

Nearly mature newborn rabbits (gestational age 29.5 days) were tracheotomized at birth and received, via the tracheal cannula, 6 ml/kg body weight of a filtered saline suspension of human meconium, 65 or 130 mg/ml. Animals were kept in body plethysmographs and ventilated for 60 min with standardized tidal volume (8-10 ml/kg). Aspiration of meconium caused, in both groups, a statistically significant reduction in lung-thorax compliance, elevated PCO2 in heart blood and reduced alveolar volume density (Vv) in histological sections. Both groups responded to treatment with exogenous surfactant (Curosurf, 200 mg/kg) with a moderate, statistically significant improvement in lung-thorax compliance, PCO2 and alveolar Vv. Our data indicate that respiratory failure after neonatal meconium aspiration may be influenced favorably by treatment with exogenous surfactant.
Glycogen Phosphorylase: Developmental Expression in Rat Liver
Authors: Bloch Clifford A. , Ozbun Michelle A. , Khan Sohaib A.
Published: October 2009

The developing fetus is vulnerable to hypoglycemia if its transplacental substrate supply is compromised. Consequently, we examined hepatic glycogen phosphorylase gene expression in the developing rat liver by comparing the relative activities of the hepatic phosphorylase enzyme, concentrations of cellular phosphorylase mRNA, and rates of transcription in isolated liver nuclei of fetal rats at 19 days of gestation, 21 days of gestation, neonatal rats, and suckling rats. Cellular phosphorylase mRNA and enzyme activity (total and phosphorylase a) increased until term. Reciprocally, the rate of phosphorylase mRNA transcription was rapid in the rats at 19 days of gestation, and declined progressively until term. These data indicate that glycogen phosphorylase gene expression is regulated post-transcriptionally in late gestation, perhaps by an increase in phosphorylase mRNA stability towards term. This results in increased phosphorylase mRNA and enzyme expression.
Cerebral Blood Flow Measurements in the Newborn Dog
Authors: Koons Anne H. , Wurtzel David , Metcalf James Michael , Fellus Jonathan , Vannucci Robert , Hiatt Mark , Hegyi Thomas
Published: October 2009

Current methods of cerebral blood flow (CBF) determination provide only discrete, episodic data and are limited in assessing dynamic changes in cerebral circulation. We adapted a venous outflow technique employing cannulation of the superior sagittal sinus in newborn puppies to measure changes in CBF rapidly and sequentially during ventilatory maneuvers. CBF velocity (CBFV) was measured simultaneously with Doppler ultrasound of the anterior cerebral artery. Relationships between flow and velocity were determined during hypocarbia, hypercarbia, hypoxia and asphyxia. During hyperventilation, CBF decreased by a mean of 14%, and CBFV by 13%, whereas maximal CO2 inhalation increased CBF by 59% and CBFV by 110%. Although CBFV exhibited the same directional changes as shown by the area under the velocity curve, the magnitude of change was not proportional to flow. CBFV indicated trends in the direction of changes in flow in individual animals, but did not correlate with flow between animals. A fluctuating unstable pattern of CBFV, previously associated with neonatal intracranial hemorrhage, was demonstrated with hyperventilation and hypocarbia. During asphyxia, CBFV ceased 2–5 min prior to CBF, presumably reflecting continued brain perfusion from vessels other than anterior cerebral artery.
Fetal pH Improvement after 24 h of Severe, Nonlethal Hypoxia
Authors: Wilkening Randall B. , Boyle David W. , Meschia Giacomo
Published: October 2009

The accumulation of hydrogen ions in fetal blood when fetal oxygenation is acutely decreased suggests metabolic instability. However, in 6 chronically prepared fetal sheep whose arterial O2 content and pO2 were abruptly reduced and maintained at about 1.7 mM and 12.6 Torr, respectively, we observed a significant decrease in fetal arterial lactate concentrations and an increase in pH to normal values after 24 h of continuous hypoxia compared with values observed after 5 h. This demonstrates that fetal pH measurements may not detect prolonged intrauterine hypoxia.
Sighs and Their Relationship to Apnea in the Newborn Infant
Authors: Alvarez Jorge E. , Bodani Jaya , Fajardo Carlos A. , Kwiatkowski Kim , Cates Donald B. , Rigatto Henrique
Published: October 2009

To test the hypothesis that sighs are mechanistically important in triggering apnea, we studied 10 preterm infants, group 1: body weight 1.8 ± 0.1 kg, gestational age 33 ± 1 weeks, postnatal age 21 ± 4 days, and 10 term infants, group 2: body weight 3.9 ± 0.15 kg, gestational age 40 ± 0.4 weeks, postnatal age 1.4 ± 0.2 days. Instantaneous ventilatory changes associated with a sigh were studied in another 10 preterm infants, group 3: body weight 1.6 ± 0.11 kg, gestational age 32 ± 0.4 weeks, postnatal age 25 ± 4 days. Ventilation was measured using a nosepiece and a flow-through system. Sleep states were recorded. Sighs were more frequent in preterm than in term infants (0.4 ± 0.04 vs. 0.18 ± 0.03 sighs/min; p = 0.03) and in rapid eye movement than in quiet sleep (0.5 ± 0.05 vs. 0.3 ± 0.05 sighs/min; p = 0.05). Of 722 apneas, 235 (33%) were associated with a sigh; of these, 113 (48%) preceded and 122 (52%) followed a sigh. Sighs induced with airway occlusion (groups 1 and 2) were more frequent after occlusion on 21 than on 35% O2, particularly when O2 saturation was low and negative airway pressure high. Instantaneous ventilation measured over 10 breaths preceding a sigh did not show any trend indicating the possible appearance of a sigh. Tidal volume increased from 7.5 ± 0.7 before the sigh to 18.9 ± 0.7 ml/kg (p < 0.01) during a sigh, with a significant increase in inspiratory drive. Ventilation increased from 0.327 ± 0.041 to 0.660 ± 0.073 1/min/kg. These findings suggest that: (1) sighs appear to have a minimal, if any, causal relationship with apnea; (2) hypoxia (21 % O2 + occlusion) seems to be an important determinant for triggering sighs, and (3) there are no changes in instantaneous ventilation preceding a sigh which indicate an imminent sigh.
When Is the Fetus First Capable of Gastric Acid, Intrinsic Factor and Gastrin Secretion?
Authors: Kelly Eric J. , Brownlee Keith G.
Published: October 2009

Little data exist regarding the activity of gastric parietal and G cells in the very immature infant. Therefore, we have examined the developing human stomach for the presence and location of parietal and G cells, by using both standard histological methods and antibodies to the H+/K+-ATPase (proton pump), intrinsic factor and gastrin in 25 fetuses (ranging from 13–28 weeks) and in 5 infants (2–21 weeks). Parietal cell activity was noted in the body, antrum and pyloric regions in all the fetal specimens examined. However, this activity was much more limited in the infant specimens. Gastrin immunoreactivity was noted in all specimens from 18 weeks of gestation onwards; this activity was located solely in the antral and pyloric region. These results indicate that the human fetus has the potential to produce gastric acid, intrinsic factor and gastrin from the middle of the second trimester.
Separate and Conjugated in vitro Effects of Clofibrate and of an Organic Extract of Rat Amniotic Fluid on Microperoxisomes of Fetal Mouse Small Intestine
Authors: Calvert R. , Dauça M.
Published: October 2009

Separate and conjugated effects of clofibrate and of an organic extract of rat amniotic fluid (RAF) on microperoxisomal response were studied in 15-day-old fetal mouse small intestine in organ culture. At the light-microscopic level, DAB-pos-itive microperoxisomes were not observed in intestinal explants cultured for 48 h with Trowell T8-medium either with (group 1) or without clofibrate (control group) or with the organic extract of RAF alone (group 2). In presence of both clofibrate and the organic extract (group 3), microperoxisomes were readily identified. At the fine structural level, microperoxisomes measured 150–175 nm in diameter in controls and in group 1 and 2. In group 3, numerous microperoxisomes measured up to 0.4 μm in diameter. Total and specific catalase activities exhibited significant decreases when intenstinal segments were cultured solely in Trowell T8-medium for 48 h. Addition of clofibrate (1), or of the organic extract of RAF (2), or of both (3) to Trowell T8-medium induced significant increases in total and specific catalase activities: 1.43-and 1.40-fold (1), 2.12- and 2.66-fold (2) and 2.92- and 3.17-fold (3). These results indicate that an organic extract of RAF contains a factor that (a) induces the formation of intestinal microperoxisomes and (b) potentiates the action of clofibrate.
Endotoxemia and Brain Bilirubin in the Rat
Authors: Hansen Thor W.R. , Maynard Edward C. , Cashore William J. , Oh William
Published: October 2009

To investigate the possible role of sepsis with endotoxemia in kernicterus, we studied the effect of endotoxin on accumulation of bilirubin and albumin in rat brain. Male Sprague-Dawley rats were given Escherichia coli endotoxin i.v. After 150 min 10 µCi 125I-bovine serum albumin was given intravenously, followed by a 1-hour bilirubin infusion. Brain bilirubin was significantly higher in the endotoxin group than in the controls (1.34 ± 0.47 vs. 0.83 ± 0.31 µg/g, p < 0.05). However, the difference between the ratios of brain bilirubin to total serum bilirubin at the time of sacrifice were not significant. Total and unbound bilirubin values were significantly higher in the endotoxin-treated group at 165 min. Endotoxemia increased the net accumulation of bilirubin in rat brain, but this increase was probably secondary to an increase in total and unbound bilirubin, rather than an increase in the transfer per se of bilirubin across the blood-brain barrier.
Postnatal Changes in Selected Bacterial Groups of the Pig Colonic Microflora
Authors: Swords William E. , Wu Ching-Ching , Champlin Franklin R. , Buddington Randal K.
Published: October 2009

The importance of the colonic microflora in health and nutrition is well known, but how they colonize and become established in the colon is not well understood. We therefore characterized the quantitative and qualitative changes of the colonic microflora during the first 120 days of postnatal development. Unlike previous studies, changes were defined for individual pigs using in situ samples collected anaerobically and aseptically from the distal colon. Although the colons were sterile at birth, they were rapidly colonized, and within 12 h bacterial densities had stabilized at 10––9-1010 bacteria/g colonic content. Facultative anaerobes, notably coliforms, initially dominated the microflora, but were supplanted within 48 h after birth by obligate anaerobes, which constituted greater than 90% of the microflora thereafter. Bacteroides spp., the predominant anaerobes in the adult colon, did not markedly increase in abundance until after weaning and were still increasing by postnatal day 120. Shifts in the relative abundances of different bacterial populations throughout the first 120 days after birth confirm previous reports that the establishment of the adult colonic microflora is a gradual, sequential process, and highlight the need to focus research on anaerobic groups.
Displacement of Bilirubin from Albumin by Berberine
Authors: Chan Eli
Published: October 2009

A study was made of the effect of berberine, the major ingredient of the Chinese herb huanglian (coptis chinensis) reported to pose some risk for kernicterus among jaundiced newborn Chinese infants, on the protein binding of bilirubin, using the peroxidase kinetic method. Berberine was found in vitro, as to its displacing effect on a molar basis, to be about tenfold superior to phenylbutazone, a known potent displacer of bilirubin, and about hundredfold to papaverine, a berberine-type alkaloid. The chronic intraperitoneal administration of berberine (10 and 20 μg/g) daily for 1 week to adult rats (mixed breed of Wistar and Sprague-Dawley) resulted in a significant decrease in mean bilirubin serum protein binding, due to an in vivo displacement effect and a persistent elevation in steady-state serum concentrations of unbound and total bilirubin, possibly due to inhibition of metabolism. The use of the herb and other traditional Chinese medicines containing a high proportion of berberine is best avoided in jaundiced neonates and pregnant women.
Prevalence and Toxigenicity of Clostridium difficile Isolates in Fecal Microflora of Preterm Infants in the Intensive Care Nursery
Authors: El-Mohandes Ayman E. , Keiser John F. , Refat Mamdouh , Jackson Barbara J.
Published: October 2009

Fecal isolates of Clostridium difficile and its toxin B were followed prospectively in 50 preterm intensive care nursery (ICN) patients. The first stool specimen was obtained after 1 week of enteral feeding, at 15 ± 1 days of life, and 2 more specimens were collected at 2-week intervals, 24 ± 1 and 32 ± 2 days of life. The stools were cultured for C. difficile, and tested for C.difficile toxin B. In the first specimen 15% of stools grew C.difficile. In the second specimen C. difficile isolation rates increased to 33% and plateaued. Toxin B was detected in 71, 93 and 100% of culture-positive stools in the first, second, and third specimens, respectively. C.difficile colonization was not associated with a higher incidence of necrotizing enterocolitis or diarrhea, and using precollected, frozen human milk did not protect from C.difficile colonization.
Low-Density Lipoprotein Catabolism does not Respond to Estrogen in the Fetal and Newborn Rat
Authors: Plonné Dietmar , Winkler Lothar , Schröter Annett , Dargel Rolf
Published: October 2009

The elimination of native and methylated low-density lipoprotein (LDL) from serum and the effect of estradiol on the serum LDL-apoB pool, the uptake of homologous [125I]-LDL into liver and adrenals, and the fractional catabolic rate (FCR) of [125I]-LDL was studied in fetal (22nd day of gestation), newborn (15th day postpartum), and adult rats. In fetal rats the receptor-mediated LDL decay accounted only for 47%, whereas in adults it was calculated to 65%. In the latter, estrogen caused (1) a diminution of the serum LDL-apoB pool by 85%; (2) an enhancement of the LDL uptake into the liver and the adrenals by 5- and 10-fold, respectively, and (3) an acceleration of the [125I]-LDL decay in the serum with a rise of the FCR by 3-fold. In contrast, neither the LDL pool and uptake nor the LDL elimination (FCR) did respond to estrogen in fetal and newborn rats. In summary, the LDL catabolism of the rat is insensitive towards estrogen in the late gestational period and during the first 2 weeks of postnatal life [3].
Influence of the Destabilisation of the Maternal Digestive Microflora on That of the Newborn Rat
Authors: Brunel A. , Gouet Ph.
Published: October 2009

By destabilising the digestive flora of pregnant rats by antibiotic treatment, it was shown that part of the digestive microflora of the neonate originated from the maternal faeces. A mixture of ampicillin, bacitracin neomycin and streptomycin associated with nystatin were administered ad libitum at three different times, 1-3, 3-5, and more than 5 days before the estimated date of littering. For each treatment, samples were taken from the faeces, teats, and vagina of dams and from the digestive tracts of neonates aged between 6 and 120 h, and analysed for the presence of staphylococci, enterococci, lactobacilli and coliform bacteria. Antibiotic treatment reduced digestive flora populations to levels lower than 102 g––1 but had less effect on the vaginal and cutaneous mammary flora. In the digestive microflora of the neonate, the enterococci were unevenly affected, whereas the staphylococci were considerably decreased and the lactobacilli almost completely eliminated; coliform bacteria were found sporadically and in small numbers. The traces of antibiotics found in milk are not sufficient to explain these modifications. Counts made in control animals on media fed the same antibiotic concentrations were not modified. This work underlined the awful consequences for the newborn of a serious perturbation of the mother flora and the necessity of its presence for a normal installation of the digestive microflora of the newborn.
Developmental Changes in the Erythrocyte Metabolism in Bandicoot Isoodon macrourus
Authors: Agar N.S. , Gemmell R.T.
Published: October 2009

Activities of 13 different enzymes were measured in the erythrocytes of juvenile and adult bandicoots, Isoodon macrourus. Seven of these enzymes had significantly (p < 0.05 or less) greater activities in the juveniles compared to the adult animals. The activity of one enzyme – phosphofructokinase – was significantly (p < 0.01) lower in the juveniles. However, the activity of NADH-methaemoglobin reductase (MR) was similar in the two groups of animals. The rates of lactate production using four different substrates (glucose, galactose, inosine and adenosine) were also higher in the juveniles. These results indicate that the erythrocytes of juvenile bandicoots are metabolically more active than those of the adult animals and follow the general pattern of higher metabolic activity in the young red cells in eutherian mammals, with possible exception of NADH-MR activity.
Soluble lnterleukin-2 Receptor and lnterleukin-2 in Human Amniotic Fluid of Normal and Abnormal Pregnancies
Authors: Shohat Batya , Shohat Mordechai , Faktor Joseph Hillel , Barkay Gad , Harell Daniela , Kozenitzky Lidia , Shohat Michael
Published: October 2009

In the present study, 63 specimens of human amniotic fluid were tested for the presence of free soluble interleukin-2 receptor (IL-2R). Thirty-two of these were also tested for the presence of IL-2. Significant reduction in free soluble IL-2R (IU/ml) or free IL-2R (IU/mg albumin) levels were found in the amniotic fluid obtained from pregnant women with Down’s syndrome fetuses as compared with normal pregnancies. In addition normal amniotic fluid was found to contain low levels of IL-2, while no IL-2 was found in amniotic fluid from pregnant women with Down’s syndrome fetuses when tested by two different tests.
Acute Effects of Cocaine on Ornithine Decarboxylase Activity in Fetal and Neonatal Rat Heart: Evidence for Cardiotoxicity
Authors: Slotkin Theodore A. , Johnson Deadre J. , Seidler Frederic J.
Published: October 2009

Fetal exposure to cocaine is associated with increased perinatal cardiac risk. In the current study, we examined the effects of acute cocaine administration on ornithine decarboxylase (ODC) activity in fetal and neonatal rat heart. ODC is a key regulatory enzyme in the control of cell differentiation and growth, and rapid changes in ODC are associated with the response to cell injury. Administration of 30 mg/kg s.c. of cocaine to pregnant rats on the 20th day of gestation caused acute elevation of fetal cardiac ODC that persisted throughout the ensuing 24 h. In contrast, the same dose given directly to neonatal rats the day after birth evoked only a short-term (1-h) stimulation of ODC that was reversed by 4 h after treatment. By 4 days of age and subsequently, cocaine was unable to elicit acute stimulation of heart ODC and only evoked inhibition of enzyme activity. Elevated progesterone levels during pregnancy have been shown to sensitize the maternal myocardium to cocaine-induced catecholaminergic effects; the greater sensitivity of fetal heart ODC to cocaine, as compared to neonatal heart, supports the hypothesis that similar enhancement of fetal cardiac irritability can contribute to cocaine-induced cell damage.
Stimulatory Effects of Insulin on DNA Synthesis in Suckling Mouse Colon
Authors: Ménard Daniel , Dagenais Pierre
Published: October 2009

The influence of insulin on the postnatal development of DNA synthesis and epithelial and muscular cell proliferation has been studied in suckling mice. Daily administration of insulin (12.5 mU/g body weight) during 3 days to 8-day-old mice induced a significant increase of the incorporation of [3H]-thymidine into DNA in the small intestine and the proximal and distal halves of the colon. The esophagus and the glandular portion of the stomach did not respond. A detailed analysis of the proximal and distal colon between 4 and 30 days revealed a decrease of [3H]-thymidine incorporation into total DNA during this period. However, the establishment of the labeling indices in specific compartments such as the epithelium and the muscularis externa revealed that the epithelial cellular proliferation increased around weaning period in both segments while a drastic reduction of cellular proliferation occurred in the muscle layer. A premature rise of the circulating insulin level induced a significant increase of the epithelial labeling indices in both colonic segments but remained without effects on the muscular layer. These results suggest an important role of insulin in the modulation of the ontogenic changes in epithelial cell proliferation of the mouse colon.
Falling Intracranial Pressure: An Important Element in the Genesis of Intracranial Hemorrhage in the Beagle Puppy
Authors: Coulter David M. , Gooch Manford
Published: October 2009

To study the role of extravascular intracranial pressure (ICP) in the genesis of intracranial hemorrhage in the beagle puppy, we measured ICP in animals on the day of birth, untreated 3-day-old controls, and 3-day-old animals treated from birth with prolactin. Baseline ICP varied substantially in all 3 groups. Only 8% of this variability was attributable to variability in mean arterial pressure and central venous pressure. ICP was lower in the 3-day-old controls, animals at high risk for intracranial hemorrhage after a hypovolemic/hypotensive insult followed by rapid volume expansion, than in the other groups which are at lower risk. Administration of a hyperosmolar insult, intraperitoneal glycerol, to animals whose ICP was relatively high promptly lowered ICP. After this treatment, the risk of intracranial hemorrhage was markedly increased in these previously low-risk groups. We conclude that the normal neonatal decrease in brain water content and the consequent fall in ICP substantially increase the risk of intracranial hemorrhage in the beagle puppy, a model which appears similar in pathophysiology to hemorrhage in the preterm human infant.
Analysis of Risk Factors Influencing Imminent Distress in Growth-Retarded Fetuses Undergoing Oxygen Test
Authors: Arduini Domenico , Rizzo Giuseppe , Garzetti Gioele , Romanini Carlo
Published: October 2009

We previously demonstrated a prognostic significance of maternal oxygen test in predicting imminent fetal distress. The purpose of this study was to investigate eventual other factors related to the length of the time interval elapsing between the Doppler diagnosis of brain sparing effect and abnormal fetal heart rate patterns. To this end we considered 101 growth-retarded fetuses free of structural and chromosomal abnormalities with a ratio between the pulsatility indices of umbilical and middle cerebral artery above the 95th centile in presence of a normal fetal heart rate pattern. The factors, other than the oxygen test, analyzed for a potential influence on this time interval were gestational age, presence of hypertension or preeclampsia, amniotic fluid index, severity of growth retardation (centile of the ultrasonographic estimated fetal weight) and 9 different Doppler indices calculated from extra- and intracardiac districts. Statistical actuarial methods were used to determine the effect of these prognostic factors on the duration of this time interval. The occurrence of abnormal fetal heart rate patterns (antepartum late heart rate decelerations) was used as censoring variable. The time interval between the entry in the study and delivery ranged from 1 to 39 days. Indications for delivery were fetal distress in 53 fetuses (52.4%) and different maternal or fetal complications in the remaining 48 fetuses. Multivariate analysis showed that the factors that independently affect the time interval between Doppler abnormalities and development of abnormal fetal heart rate patterns are the oxygen test (p ≤ 0.001), the percentage of reverse flow in inferior vena cava (p ≤ 0.001), gestational age (p ≤ 0.01) and the presence of hypertension (p ≤ 0.05). The knowledge of these prognostic factors may be useful in the clinical management of growth-retarded fetuses.
Erythromycin Increases Gastric Antral Motility in Human Premature Infants
Authors: Tomomasa Takeshi , Miyazaki Masataka , Koizumi Takenobu , Kuroume Takayoshi
Published: October 2009

The aim of this study was to determine if erythromycin (EM), which is a potent motilin agonist, alters gastrointestinal motility in premature infants. Six infants who were born after 23–30 weeks gestation and weighed 825–1,408 g at birth were studied when 6–31 days old. Intraluminal pressure changes within the gastric antrum and proximal duodenum were recorded. We infused EM 0.75 mg/kg intravenously for 15 min and we compared gastric and duodenal contractions for 30 min between before and after the initiation of EM infusion. In these preterm infants the migrating complex was not present, and was not induced by EM. However, in all 6 infants EM increased nonpropagating antral clusters of contractions (p < 0.05). The antral motility index increased 4-fold (p < 0.05). We concluded that human premature infants have functioning motilin receptors.
Effects of Diets with Different Content in Protein and Fiber on Embryotoxicity Induced by Experimental Diabetes in Rats
Authors: Giavini E. , Airoldi L. , Broccia M.L. , Roversi G.D. , Prati M.
Published: October 2009

Three groups of streptozotocin-diabetic rats were maintained during pregnancy on three hyperproteic diets with different protein contents. These differences were compensated by an equal quantity of fiber (group 1: protein 55.0%, fiber 4.5%; group 2: 45.0%, 14.0%; group 3: 35.0%, 24.0%). Three groups of nondiabetic pregnant rats were fed with the same diets and served as control. The differences of the daily protein intake among the diabetic groups were less pronounced than those expected on the basis of the diet composition, and the embryopathic effects (reduced fetal weight, increase in malformation and resorption rate) were not statistically different among the three groups of diabetic animals. The frequency of congenital malformations was higher than that observed in a previous experiment in diabetic rats maintained on a standard diet, but much lower than that observed in animals fed on a purified, fiber-poor, normoproteic diet. When the caloric intake of the diabetic rats in the different groups was determined it was found to be similar for all of them and also similar to the caloric intake of the rats given a standard nonteratogenic diet (in previous experiments), while the rats maintained on a normoproteic, teratogenic diet increased their caloric intake. These results seem to indicate that the diet composition greatly influences the intake of food and calories of pregnant diabetic rats and this may play a role in modulating the embryopathic effect of diabetes.
Effects of Hyperbaric Oxygen on Rat Embryos
Authors: Sapunar Damir , Saraga-Babić Mirna , Peruzović Marijana , Marušić Matko
Published: October 2009

The aim of the study was to investigate the toxic effects of hyperbaric oxygen (HBO) on rat embryos. Two groups of Fischer pregnant rats were exposed to oxygen at pressures of 324 and 426 kPa for 90 min per day for 5 consecutive days (8–12 days of gestation). The third group was exposed to normobaric oxygen for 12 h on the eighth day of gestation. Two control groups were used; the first was comprised of intact and the second of sham-treated animals. The HBO treatment did not significantly affect maternal weight gain or reduce litter size, nor did it induce any embryonic abnormalities. However, the fetal body weight was reduced and the placental weight increased in the groups exposed to HBO at pressures of 324 and 426 kPa. When female fetuses which had been exposed to oxygen at 324 or 426 kPa were compared to the intact control group, a reduction in wet weights of 9.2 (p < 0.05) and 12.1 % (p < 0.01), respectively, was noted. Male fetuses exposed to oxygen at 324 and 426 kPa displayed a reduced body weight of 11.7 (p < 0.01) and 16.6% (p < 0.01), respectively. Placental weight was increased by 18.9 (p < 0.01) and 23.6% (p < 0.01) in the groups exposed to oxygen at 324 and 426 kPa, respectively. These data suggest that HBO, either at 324 or 426 kPa, is not potent at inducing malformations and that the largest embryotoxic effects are upon fetal body weight and placental weight. However, the histological examination of placentas revealed alterations in labyrinthine blood vessels and a statistically significant thickening of the placental barrier. In conclusion, this study suggests that transient interference with normal placentation is probably sufficient to cause permanent maldevelopment of the placenta and embryo.
Age-Related Changes in Endotoxin Sensitivity and the Febrile Response of Newborn Rabbits
Authors: Hull D. , McIntyre J. , Vinter J.
Published: October 2009

Thermoregulatory responses to pyrogens in the immediate newborn period have been reported suppressed or undeveloped. In this study we investigated these responses in the newborn rabbit. Endotoxin (Escherichia coli LPS) was injected intraperitoneally in rabbits at different doses on day 0 (day of delivery), 1 or 3 of life, each animal being used only once. Oxygen consumption (VO2) and colonic temperature (Tc) were measured continuously for up to 5 h following endotoxin administration. On all days, a thermogenic response of a similar pattern was seen. At a low dose of endotoxin, there was a monophasic rise in VO2 that reached a peak at 2 h, followed by a plateau phase lasting a further 2-3 h. At an intermediate dose the response was biphasic with an initial smaller peak after 45-60 min and a second more sustained peak developing by about 2 h. At a higher dose the depression between the two peaks became deeper and longer with the second peak becoming more delayed and weaker. As animals got older, the doses needed to produce this sequence increased. On day 0 the increased VO2 caused by endotoxin was not accompanied by an increase in Tc. By day 3, Tc rose with the increase in VO2. We conclude that rabbits on the day of delivery respond to endotoxin with an increase in VO2 and by day 3 this is accompanied by an increase in Tc. The pattern of VO2, changes from monophasic to biphasic with increasing doses of endotoxin and the sensitivity to endotoxin decreases over the first 3 days of life.
Endothelium-Dependent Relaxation and the Acute Pulmonary Vascular Response to Alveolar Hyperoxia in Neonatal Pigs
Authors: Day Ronald W. , Klitzner Thomas S. , Ignarro Louis J.
Published: October 2009

To determine whether hyperoxia increases the production of endothelium-derived relaxing factor, we studied the effect of oxygen on pulmonary vascular ring tension and regional lung perfusion. In vitro, hyperoxia stimulated endothelium-independent constriction of neonatal porcine pulmonary arterial rings. In vessels with intact endothelium, hyperoxia stimulated a concomitant increase in the production of endothelium-derived relaxing factor. In sedated neonatal pigs, colored microspheres were used to evaluate relative lung perfusion when two lung regions were independently ventilated with room air, and subsequently, when one lung region was ventilated with 100% oxygen. The proportion of flow to the hyperoxic lung region was not significantly increased until the production of endothelium-derived relaxing factor was inhibited by NG-monomethyl-L-arginine or NG-nitro-L-arginine methyl ester. Thus, hyperoxia stimulated opposing effects on the tension of isolated vascular rings. One mechanism of oxygen-mediated relaxation results from an increase in the production of endothelium-derived relaxing factor. However, in vivo, alveolar hyperoxia may stimulate an acute pulmonary vasodilatory response which is not mediated by endothelium-derived relaxing factor.
Dermatoglyphic Asymmetry in Fetal Alcohol Syndrome
Authors: Wilber Ellen , Newell-Morris Laura , Streissguth Ann Pytkowicz
Published: October 2009

The hypothesis was tested that prenatal alcohol exposure disrupts developmental homeostasis, as reflected in increased dermatoglyphic fluctuating asymmetry. Twenty-two patients with fetal alcohol syndrome (FAS) and 9 with fetal alcohol effect (FAE) were matched for sex with 31 controls. On each patient, the right a–b dermal ridge count was subtracted from the left to obtain the asymmetry value. Group differences were tested by analysis of variance (ANOVA), and paired two-tailed t tests. Mean asymmetry increased from control (1.94) through FAE (2.78) to the FAS (4.00) group. Group differences were significant by ANOVA (p = 0.0066); only the FAS and control group differed by t test (p = 0.0025). The results support the hypothesis of increased decanalization of prenatal development in the presence of alcohol.
Fetal Blood Cell Membrane Fluidity in Small for Gestational Age Fetuses
Authors: Lemery Didier J. , Beal Valerie , Vanlieferinghen Philippe , Motta Claude
Published: October 2009

Blood cells membrane fluidity was assessed prenatally by fluorescence polarization for anisotropy, microviscosity, degree of order and fusion activation energy in 20 fetuses who underwent ercutaneous umbilical blood sampling for intrauterine growth retardation (IUGR) and in 25 controls for normal weight sampled for other indications. Simultaneously, blood samples were collected from each mother for comparison. Regulators of membrane fluidity (i.e., cholesterol, phospholipids, free fatty acids) were also assessed. Student t test was employed for analysis. Membrane fluidity was lower in control fetal cells than in adults (p < 0.05) and lower in IUGR fetuses than in controls (p < 0.05). The mechanism may involve a low cholesterol concentration and a low unsaturated/saturated free fatty acids ratio in fetal blood cells membranes and plasma. Fetal cells membrane fluidity reflects in part fetal nutritional status.
Erythrocyte Li+i-Na+o Countertransport in the Newborn
Authors: Agam G. , Deutsch I. , Karplus M. , Livne A.A.
Published: October 2009

The present study investigates the erythrocyte Lii+-Nao+ countertransport (CT) in the newborn. Erythrocytes of term infants exhibit no or very low CT activity at birth (0.025 ± 0.011 mmol Li/1 RBC·h). CT rates increase gradually and reach adult values within the 4th-7th day of life (0.225 ± 0.018 mmol Li/1 RBC·h). CT activity in healthy preterm infants at birth is not significantly different from that in term infants (0.014 ± 0.007 mmol Li/1 RBC·h). Postnatal maturation of CT activity in preterm infants is similar to that found in term infants and is independent of gestational age. However, CT rates at birth of premature infants subjected to prenatal stress are significantly higher (0.082 ± 0.017 mmol Li/1 RBC·h). It is concluded that erythrocyte CT activity in the newborn reaches adult values within the first week of life, apparently reflecting the postnatal maturation of the CT system in the cell membrane. We suggest that prenatal stress induces the synthesis of the CT protein in utero.
Brain Natriuretic Peptide Levels in the Umbilical Venous Plasma Are Elevated in Fetal Distress
Authors: Itoh Hiroaki , Sagawa Norimasa , Hasegawa Masaaki , Okagaki Atsuhiko , Inamori Kumiko , Ihara Yoshiyuki , Mori Takahide , Suga Shin-ichi , Mukoyama Masashi , Shirakami Gotaro , Nakao Kazuwa , Imura Hiroo
Published: October 2009

We measured, by a specific radioimmunoassay, brain-natriuretic-peptide-like immunoreactive (BNP-LI) levels in the umbilical venous and arterial plasma of normal and distressed newborns. The indicated BNP-LI level in umbilical arterial plasma of normal newborns (3.5 ± 0.9 fmol/ml, mean ± SEM, n = 10) was significantly higher than that in umbilical venous plasma of the same newborns (2.2 ± 0.5 fmol/ml). In the distressed newborns at term, the indicated BNP-LI level in umbilical venous plasma was 62.2 ± 25.7 fmol/ml (n = 4), which was 19-fold higher than that of elective cesarean section cases (3.2 ± 0.3 fmol/ml, n = 6; p < 0.05). The findings demonstrated that BNP was present in the human fetal circulation and that the plasma BNP level was elevated under fetal distress conditions.
Effects of Doxapram on Carotid Chemoreceptor Activity in Newborn Kittens
Authors: Bairam A. , Marchal F. , Crance J.P. , Vert P. , Lahiri S.
Published: October 2009

Doxapram is a respiratory stimulant which acts on peripheral chemoreceptors and central respiratory neurons in a dose-dependent fashion in the adult cat. In the newborn, the mechanisms of action of doxapram are still unclear. To evaluate the effects of doxapram on the carotid chemosensory discharge and its relationship with dopaminergic mechanisms in the carotid body, two groups of kittens less than 13 days old, anesthetized, artificially ventilated and paralyzed, were prepared for the recording of a single or a few chemosensory afferents of the carotid sinus nerve. The chemosensory activity was recorded under five conditions of inspired gas mixtures (21 and 8% O2 in N2, 100% O2, 5 and 10% CO2 in O2). Group 1 (n = 9) received only doxapram and group 2 (n = 8) was pretreated with haloperidol (1 mg/kg), a dopamine D2-receptor blocker, before receiving doxapram. Doxapram significantly stimulated the discharge rate of the carotid chemoafferents under all conditions of inspired gas. The chemosensory discharge was increased by haloperidol, and was raised further after doxapram by an amount similar to group 1. For instance, in normoxia, the activity increased from 2.9 ± 0.4 to 7.5 ± 0.9 impulse/s (mean ± SEM, p < 0.01) in group 1 and from 3.8 ± 0.6 to 9.1 ± 1.0 impulse/s (p < 0.01) in group 2. These results indicate that the mechanisms of response of carotid chemoreceptor to doxapram are developed in the newborn kitten and doxapram acts independent of the dopaminergic mechanisms in the carotid body.
In vitro Thermogenic Activity of Rat Brown Adipose Tissue in Neonatal Period
Authors: Yahata Takehiro , Kuroshima Akihiro
Published: October 2009

The roles of noradrenaline (NA) and glucagon in ontogeny of nonshivering thermogenesis (NST) were investigated in rats. The relative brown adipose tissue (BAT) mass to body weight was larger in the neonates compared with those of adult animals. The NA level in BAT was low at birth and then increased rapidly to adult level, whereas glucagon level at birth was as high as that in the adult. The thermogenic function of BAT was estimated by measuring the in vitro oxygen consumption of the tissue blocks. NA and glucagon stimulated the oxygen consumption of BAT maximally in a dose of 1 μg/ml, respectively. The response of the tissue to NA from the neonates just after birth was high compared with that in adult animals. The high values persisted throughout the early neonatal period, and decreased around the weaning period. The response to glucagon exhibited similar pattern. These results indicate that glucagon as well as NA play a significant role in NST in BAT during the early stage of neonatal period.
Expression of the Genes for the Mitochondrial and Cytosolic Forms of Phosphoenolpyruvate Carboxykinase in Avian Liver during Development
Authors: Savon Summer , Hakimi Parvin , Hanson Richard W.
Published: October 2009

Gluconeogenesis in the chicken has unique features due in part to the presence of two isozymes of PEPCK, a cytosolic form, PEPCK-C, and a mitochondrial form, PEPCK-M, which have novel patterns of expression. Here we show that, in contrast to mammals, in which PEPCK-C is not present in liver until after birth, avian PEPCK-C is expressed throughout embryonic life with mRNA levels gradually decreasing as development proceeds and becoming negligible at time of hatching. In addition two distinct mRNAs for PEPCK-M are expressed during development with specific patterns that vary among individual birds. These differences are likely to be genetic, as hormonal treatment of a chicken hepatoma cell line indicates that whereas the mRNA levels for PEPCK-C are hormonally regulated, the expression of PEPCK-M mRNA is unresponsive.
Effects of Intrauterine Growth on Intestinal Length in the Human Fetus
Authors: Shanklin Douglas R. , Cooke Richard J.
Published: October 2009

Standards for human fetal intestinal length are not well established but have important implications for the care of the preterm and intrauterine growth-retarded (IUGR) infant. Our purpose was to examine the relationship between intrauterine growth and intestinal length in the human fetus. One hundred infants were studied. Birth weight and gestational age ranged from 76 to 4,385 g and from 12 to 42 weeks, respectively. Twenty-one infants were noted to be IUGR. Intestinal length (total, small, large) increased (p < 0.0001) with birth weight, gestational age, and crownheel length but was reduced in IUGR infants. The ratio of body weight to intestinal length increased with gestation but was also reduced in IUGR infants. In conclusion, a reduced functional mass, as suggested by decreased intestinal length or body weight:intestinal length ratio, may contribute to the poor weight sometimes seen in the very-low-birth weight or IUGR infant.
Catecholamine Response at Birth in Preterm Newborns
Authors: Mehandru Prem L. , Assel Barbara G. , Nuamah Isaac F. , Fanaroff Avroy A. , Kalhan Satish C.
Published: October 2009

We compared the extrauterine adaptation of preterm with term newborn infants, by sequentially measuring plasma catecholamine (CAT) levels at birth and during the first 24 h of life. Twenty-seven preterm appropriate-for-gestational-age (AGA) infants, less than 35 weeks gestation, were compared with 26 healthy near-term AGA infants. Modes of delivery and umbilical arterial pH (mean 7.28) did not differ. Infants with asphyxia, presumed sepsis or hypoglycemia were excluded. CAT (norepinephrine, epinephrine, dopamine) levels were measured by radioenzymatic assay in blood samples from maternal vein, cord vein, cord artery and blood samples obtained at 1, 2 and 24 h of postnatal age. At birth, the cord arterial CAT levels were significantly higher than maternal venous CAT levels in both groups of neonates. Plasma epinephrine levels (mean ± SD) at 1 and 2 h of postnatal age were significantly higher in preterm than in near-term newborns (0.98 ± 0.82 nmol/l vs. 0.30 ± 0.21 nmol/l at 1 h; 0.98 ± 0.68 nmol/l vs. 0.28 ± 0.29 nmol/l at 2 h; p < 0.05). The norepinephrine and dopamine measurements did not differ between the two groups studied at birth, 1, 2 and 24 h of postnatal age. These data indicate that the preterm infants (25-35 weeks gestation) are capable of mounting a catecholamine response at birth similar to near-term newborns. The persistent elevation of epinephrine in preterm infants at 1 and 2 h of life may be attributed to either slower clearance of epinephrine or continued stimulation during clinical care in the NICU.
Increase in Plasma Platelet-Activating Factor Levels in Enterally Fed Preterm Infants
Authors: MacKendrick William , Hill Nicole , Hsueh Wei , Caplan Michael
Published: October 2009

Because platelet-activating factor (PAF) has been implicated in the pathogenesis of neonatal necrotizing enterocolitis (NEC), we designed a prospective study to examine plasma PAF levels during the first 14 days of feeding in a population of neonates of less than 32 weeks gestation. We found that significantly more patients had detectable plasma PAF levels on days 3 and 14 of feeding when compared to their prefeeding levels (7% on day 0 vs. 26% at day 3, p = 0.04; none on day 0 vs. 18.5% at day 14, p = 0.01). This finding could not be explained by decreased plasma activity of acetylhydrolase, the PAF breakdown enzyme, spontaneous endotoxinemia or a maturational effect. None of the infants who developed detectable PAF levels after feedings were begun went on to develop NEC. We conclude that our findings may reflect increased intestinal PAF production with the provision of feedings to some premature infants. However, this phenomenon by itself does not appear to be a sufficient condition for the subsequent development of NEC.
Unconjugated and Conjugated Bilirubin Pigments during Perinatal Development
Authors: Rubaltelli Firmino F.
Published: October 2009

One thousand four hundred and fifty-four consecutive full-term neonates, delivered over a period extending from February 1, 1991 to January 31, 1992 were prospectively studied during the first days of life to determine if breast-feeding and hyperbilirubinemia were related. Six hundred and five infants were exclusively breast-fed on demand, 623 received both breast- and formula-feeding, and 226 were exclusively formula-fed. Of the 1,454 newborns studied, 70 (4.8%) presented with a bilirubin serum concentration > 12.9 mg/dl (4.62% in the breast-fed group, 5.45% in the group fed with mother’s milk with supplements, and 3.54% in the artificial formula group; the differences were not significant). Percent mean weight losses on the 3rd and 5th days were not significantly different. Babies breast-fed on demand seem to have a low incidence of hyperbilirubinemia similar to that found in formula-fed neonates.