bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of L-Aspartate on the Ventilatory Response to Hypoxia in Sedated Newborn Piglets
Authors: Navarro Hugo , Suguihara Cleide , Soliz Amed , Hehre Dorothy , Huang Jian , Bancalari Eduardo 
Published: April 2003

<i>L</i>-Aspartate (<i>L</i>-ASP) acts as an excitatory amino acid neurotransmitter at the synapses of brain stem respiratory neurons. In order to determine the effect of <i>L</i>-ASP on the neonatal ventilatory response to hypoxia, 9 control piglets [age 4.3 ± (SD) 0.9 days, weight 1.9 ± 0.5 kg] and 9 <i>L</i>-ASP-treated animals [age 5.0 ± (SD) 1.4 days, weight 2.1 ± 0.7 kg] were studied. Minute ventilation, oxygen consumption, arterial blood pressure, and blood gases were measured in sedated piglets while spontaneously breathing room air and during 1, 5, and 10 min of hypoxia (O<sub>2</sub> concentration in inspired gas 0.10). Measurements were obtained before and 60 min after the administration of <i>L</i>-ASP (580 mg/kg i.v. over 1 h) or 5% dextrose solution. In the control animals, the ventilatory response to hypoxia was similar before and after dextrose infusion. In contrast, a significant and sustained increase in ventilation was observed at 1, 5, and 10 min of hypoxia after the administration of <i>L</i>-ASP. Changes in oxygen consumption, heart rate, arterial blood pressure, pH, and arterial O<sub>2</sub> tension with hypoxia were similar before and after the <i>L</i>-ASP infusion, while the arterial CO<sub>2</sub> tension decreased significantly during hypoxia after the administration of <i>L</i>-ASP. These data suggest that the excitatory amino acid <i>L</i>-ASP is an important mediator of the hypoxic hyperventilation in the neonate. We speculate that the administration of exogenous <i>L</i>-ASP modifies the balance of central nervous system neurotransmitters during hypoxia, resulting in predominance of excitatory neurotransmission.
Postnatal Development of Urea Synthesis Capacity in Preterm Infants with Intrauterine Growth Retardation
Authors: Boehm G. , Teichmann B. , Jung K. , Moro G. 
Published: April 2003

The postnatal development of the urea-synthesizing capacity was studied in 21 preterm infants with intrauterine growth retardation (IUGR) and compared with results found in 12 infants without IUGR as controls. The urea-synthesizing capacity was estimated by the ratio Q of <sup>15</sup>N abundance of ammonia and urea in 6-hour urine samples collected after enteral administration of 3 mg [<sup>15</sup>N]H<sub>4</sub>Cl/kg body weight. The measurements were performed on the first day when a protein intake of 3.0–3.5 g/kg/day and an energy intake of 120 kcal/kg/day were tolerated (study day 1: postnatal 14–21 days) and on the day of discharge from the hospital (study day 2: postnatal age 39–56 days). The group of infants with IUGR was subdivided in one group of infants who developed catch-up growth (n = 12) and one group who did not demonstrate catch-up growth (n = 9). On study day 1, the Q values of the IUGR infants without catch-up growth were significantly higher than those of the IUGR infants with catch-up growth (13.4 ± 2.3 vs. 9.2 ± 2.2) or of the control infants without IUGR. During the time period from study day 1 to study day 2 the Q values of the IUGR infants with catch-up growth decreased significantly (9.2 ± 2.2 vs. 4.8 ± 2.0; p < 0.001) and were in the range of the control infants without IUGR. In contrast, the Q values of the IUGR infants without catch-up growth did not significantly change during the study period (13.4 ± 2.3 vs. 11.3 ± 2.8; p = 0.097). On both study days there was a significant correlation between the Q values and the degree of IUGR (study day 1: r = 0.652, p < 0.01; study day 2: r = 0.842, p < 0.001). The data indicate that the urea-synthesizing capacity of preterm infants increases during early postnatal life and that severe IUGR may impair this development. Metabolic investigations using urea as marker for evaluation of optimal quantity or quality of dietary proteins should carefully be interpreted when infants with severe IUGR are studied.
Biotin Plasma Levels of theHuman Fetus
Authors: Mantagos S. , Malamitsi-Puchner A. , Antsaklis A. , Livaniou E. , Evangelatos G. , Ithakissios D.S. 
Published: April 2003

Biotin is an important vitamin for cellular function and growth and, therefore, essential for fetal development. The fetus is exclusively dependent on maternal biotin supply. Since biotin is not produced within the body, maternal biotin levels depend on dietary intake. In order to investigate the biotin status of the human fetus, we measured the plasma biotin levels in 15 pregnant women and their fetuses who underwent amniocentesis and fetal blood sampling at 18–24 weeks of gestation for prenatal diagnosis of thalassemia. Maternal biotin was found to be 131 ± (SD) 102 ng/l and fetal biotin 784 ± 327 ng/l (p < 0.0001). Our findings are indicative of an active transport mechanism of biotin through the placenta in favor of the fetus.
The Effect of Recombinant TGFα, Human Milk, and Human Milk Macrophage Media on Gut Epithelial Proliferation Is Decreased in the Presence of a Neutralizing TGFα Antibody
Authors: Wagner Carol L. , Forsythe Donna W. , Wagner Mark T. 
Published: April 2003

<b>Objective:</b> An in vitro model was devised to compare the relative effects of recombinant transforming growth factor-alpha (TGFα), aqueous human milk, and human milk macrophage (HMM) medium on human fetal small intestinal cell (FHs-74) proliferation. <b>Methods:</b> Recombinant TGFα at increasing concentrations (range 0.01–1,000 ng/ml media), the aqueous fraction of human milk (AHM), or HMM medium was added to FHs-74 cells in the presence or absence of a neutralizing TGFα antibody (1 µg/ml medium). At 24 h, cell proliferation was measured and expressed as percent control. The experimental variables were (1) activators of cell growth (TGFα, AHM, and HMM medium); (2) increasing concentrations of TGFα, and (3) neutralizing antibody to TGFα. The dependent variable for all experiments was cell proliferation. <b>Results:</b> Significant effects for growth stimulators and TGFα concentration as measured by cell proliferation were found. Specifically, there was a dose-dependent effect of TGFα on cell proliferation to the 5-ng/ml concentration, with a plateau reached in cell proliferation at higher concentrations. The stimulatory effect of TGFα was decreased in the presence of TGFα antibody (mean ± SD 22 ± 7.1% decline, p < 0.001). In the presence of TGFα antibody, there was a 25 ± 3.1% decline in HM-stimulated growth (p < 0.004), and a 27.6 ± 3.2% decline in HMM medium-stimulated growth (p < 0.001). <b>Conclusions:</b> Neutralization of recombinant TGFα and that present in human milk and HMM medium by TGFα antibody led to a consistent decrease in in vitro human fetal small intestine epithelial proliferation without affecting cell viability. These results support the hypothesis that TGFα, whether derived from human recombinant sources, human milk or HMM medium has a measurable, trophic effect on in vitro human gut epithelial cells.
CO<sub>2</sub> Reactivity of the Cerebral Hemoglobin Concentration in Healthy Term Newborns Measured by Near Infrared Spectrophotometry
Authors: Dietz Vera , Wolf Martin , Keel Matthias , Siebenthal Kurt , Baenziger Oskar , Bucher Hans-Ulrich 
Published: April 2003

CO<sub>2</sub> reactivity of cerebral hemoglobin concentration was studied in 16 healthy term neonates on days 1 and 4 after birth using the near infrared spectrophotometry (NIRS) technique. The aim was to establish data on the physiological range of CO<sub>2</sub> reactivity in healthy newborns and to investigate the influence of postnatal age on it. The CO<sub>2</sub> reactivity measured by NIRS is expressed as the change of the total cerebral hemoglobin concentration (tHbR) per change of CO<sub>2</sub> tension in µmol/l/kPa. We evaluated CO<sub>2</sub> reactivity during increases and decreases of transcutaneous CO<sub>2</sub> partial pressure and found in our methodological setting the data of the increases more reliable. In all infants but 1 we found a tHbR on day 1 with a mean value of 8.19 µmol/l/kPa (–1.39 to 18.87), in all infants on day 4 with a mean value of 9.54 µmol/l/kPa (2.76–25.88). There is a trend to higher values between day 1 and day 4 (difference = 2.25 µmol/l/kPa; p = 0.08). The noninvasive NIRS technique enabled us to test the cerebrovascular CO<sub>2</sub> reactivity of the tHbR for the first time in healthy term newborns. Data on its physiologic range and variability are presented and compared to findings from ventilated infants and other age groups. As the CO<sub>2</sub> reactivity might be an indicator for infants at risk of cerebral damage, it is necessary to have data on the physiological range of this parameter.
Diagnostic Value of Troponin T in Neonates of Mild Pre-Eclamptic Mothers
Authors: Narin Nazmi , Çetin Neşide , Kılıç Hüseyin , Başbuğ Mustafa , Narin Figen , Kafalı Mehpare , Ü züm Kazım , Genç Ercan , Üstünbaş H. Basri 
Published: April 2003

The measurement of myocardial damage by newer, highly specific markers of myocardial damage is now possible, including cardiac structural proteins such as troponin T (TnT). In neonates of pre-eclamptic mothers, it identifies minor myocardial damage missed by other biochemical markers. The present study was designed to determine the diagnostic value of TnT concentrations in neonates of pre-eclamptic mothers. Fifteen neonates of pre-eclamptic mothers were studied (9 boys and 6 girls), and 17 healthy full-term neonates (9 boys and 8 girls) were selected as a control group. The serum TnT concentration in neonates of pre-eclamptic mothers (0.70 ng/ml) was significantly higher than that in the control group (0.10 ng/ml). In an echocardiographic study, the mean mitral peak velocity at an atrial contraction (A) value of 39 cm/s in neonates of pre-eclamptic mothers was significantly lower than that in the control group (53 cm/s), and the mean mitral peak velocity of early diastole to peak velocity of the atrial contraction (E/A) value (1.75) in neonates of pre-eclamptic mothers was significantly higher than that in the control subjects (1.23). In conclusion, our study demonstrated high levels of cardiac TnT, lower mitral A values and high mitral E/A values in neonates of pre-eclamptic mothers, presumably associated with mild myocardial damage in the neonates of pre-eclamptic mothers.
Insulin Modulates Cellular Proliferation in Developing Human Jejunum and Colon
Authors: Ménard Daniel , Corriveau Lina , Beaulieu Jean-François 
Published: April 2003

Several lines of evidence suggest an important role for insulin in the regulatory mechanism of rodent small intestinal development. To investigate its potential implication in human gut, the immunofluorescent localization of insulin receptors (IR) and the influence of insulin (30 µU or 3 mU/ml) on [<sup>3</sup>H]-thymidine incorporation and on lactase and alkaline phosphatase activities were studied in fetal jejunum and colon (14–19 weeks). We demonstrate the early presence of IR, mainly detected in the basolateral portion of enterocytes and colonocytes along the crypt-villus axis. Insulin increased [<sup>3</sup>H]-thymidine incorporation as well as epithelial labeling indices in cultured explants from jejunum and colon without affecting enzymic activities. This study establishes, for the first time, that insulin stimulates proliferation of epithelial cells expressing IR in both segments without affecting brush border hydrolases in the developing human gut.
Effect of Initial Nitric Oxide Concentration on Outcome in Infants with Persistent Pulmonary Hypertension of the Newborn
Authors: Wood Karen S. , McCaffrey Martin J. , Donovan Jocelyn C. , Stiles Alan D. , Bose Carl L. 
Published: April 2003

A randomized nonblinded comparison of two treatment groups was performed to determine whether treatment of infants with persistent pulmonary hypertension of the newborn using a continuous 6-ppm dose of inhaled nitric oxide (iNO) changes the likelihood of death or utilization of extracorporeal membrane oxygenation (ECMO) when compared to infants treated with 20 ppm iNO for 4 h followed by 6 ppm. Twenty-nine infants with a gestational age ≥34 weeks and a diagnosis of persistent pulmonary hypertension of the newborn were enrolled during the 3- year study period. The relative risk (20/6 vs. 6 ppm) for treatment with ECMO was 3.11 (p = 0.02), for death it was 2.80 (p = 0.32), and for either death or ECMO it was 3.42 (p = 0.006). There was no apparent advantage of treatment with a higher dosage of iNO at the initiation of therapy in the reduction of death or utilization of ECMO. These data suggest that a continuous lower dose of iNO results in a comparable improvement in oxygenation as a short exposure of higher dose iNO at the initiation of therapy.
Treadmill Training EnhancesGlucose Tole rance More in Pregnant than in Virgin Rats
Authors: Muñoz C. , López-Luna P. , Herrera E. 
Published: April 2003

To determine whether aerobic training throughout gestation modifies glucose tolerance, female Wistar rats were mated or kept nonpregnant and run or not on a 10° slope treadmill for 5 days/week at 20 m/min, starting with a 20-min run, and with a progressive daily increase of 5 min, reaching a 75-min run on the 20th day of protocol or gestation. The exercise protocol did not modify food intake, maternal and fetal weights, litter size or blood lactic acid levels. The rise in blood glucose after an oral glucose load (2 g/kg body weight) did not differ between trained and untrained nonpregnant rats but was lower in trained than in untrained pregnant rats. In the untrained rats the rise in plasma insulin levels after the glucose load was much greater in pregnant than in nonpregnant rats; in trained rats this difference between groups was attenuated by the greater effect of exercise decreasing the plasma insulin response to the glucose load in pregnant than in nonpregnant rats. Thus, an aerobic exercise protocol that does not modify the outcome of pregnancy does significantly reduce the altered oral glucose tolerance in pregnant rats and only has a minor effect in nonpregnant rats.
Effects of Hypoxia and Reoxygenation with 21% and 100%-Oxygen on Cerebral Nitric Oxide Concentration and Microcirculation in Newborn Piglets
Authors: Kutzsche Stefan , Kirkeby Ole J. , Rise Ingunn R. , Saugstad Ola D. 
Published: April 2003

Bioelectric sensors for continuous registration of nitric oxide (NO) concentrations in tissues provide a new tool for invasive measurement of this gaseous molecule. This study sought to validate cerebral NO measurements using an amperiometric sensor. A series of experiments in 1- to 3-day-old piglets was carried out to study the response of NO and microcirculation during hypoxia (F<sub>i</sub>O<sub>2</sub> 0.06) and reoxygenation with 100% and 21% oxygen. Two-channel laser Doppler flowmetry was performed in the forebrain cortex. Significant decreases of NO levels were observed immediately after induction of hypoxemia (p < 0.05). During reoxygenation with 21 or 100% O<sub>2</sub> for 30 min, NO increased significantly compared to the values at the end of hypoxia (p < 0.05). The increase of NO levels in the 100% oxygen group was greater than the increase in the 21% oxygen group (p < 0.05). There were no significant differences between the two groups during the following 3.5 h of observation. A significant increase in CBF was found in the first 2 min of hypoxia (p < 0.05), it then continued to fall to values significantly lower than baseline values at the end of hypoxemia (p < 0.05). During reoxygenation CBF normalised and there were consistent but no significant differences between the two reoxygenation groups. We conclude that NO concentration decreased during the course of hypoxia. Hypoxia-induced cerebral hyperaemia occurred in spite of significantly lower NO concentrations. Reoxygenation with 21 or 100% O<sub>2</sub> restored CBF in both groups similarly, although values were higher after reoxygenation with 100% O<sub>2</sub> compared to air. In fact, reoxygenation with 100% O<sub>2</sub> led to supranormal levels of NO by contrast to 21% O<sub>2</sub>.
Effect of C1-Inhibitor in a Rat Model of Necrotizing Enterocolitis
Authors: Sonntag Josef , Wagner Mathias H. , Liu Guosheng , Vogel Martin , Walka Matthias M. , Maier Rolf F. 
Published: April 2003

Our aim was to investigate the effect of C1-inhibitor (C1-INH) in a rat model of necrotizing enterocolitis (NEC). Twenty-four anesthetized and artificially ventilated rats received 0.1 mg/kg endotoxin. Fifteen minutes later, the animals in the study group (n = 12) were treated with 200 IU/kg C1-INH whereas the control animals (n = 12) received normal saline. In all animals, FiO<sub>2</sub> was reduced after 90 min from 0.21 to 0.05 and ventilation continued until 180 min or death. All animals developed shock symptoms. Drop in mean arterial blood pressure was more pronounced and survival time was shorter in the control group. Whereas the C1-INH activity increased in the study group, it decreased in the control group. The extent of macroscopic intestinal lesions did not differ between the groups. In conclusion, C1-INH did not prevent shock, but mitigated and delayed its course.
Vascular Endothelial Growth Factor in Pulmonary Lavage Fluid from Premature Infants: Effects of Age and Postnatal Dexamethasone
Authors: D’Angio Carl T. , Maniscalco William M. , Ryan Rita M. , Avissar Nelly E. , Basavegowda Kumar , Sinkin Robert A. 
Published: April 2003

Corticosteroids are used to ameliorate bronchopulmonary dysplasia (BPD). They also affect normal development, including the expression of growth factors such as vascular endothelial growth factor (VEGF). Deep pulmonary lavage specimens were collected on days 1, 3, 7 and 28 of life in 40 infants of <34 weeks of gestation at birth during a randomized controlled trial of two doses of dexamethasone (DEX) at 12 and 24 h of age for BPD prophylaxis. VEGF was measured by enzyme-linked immunosorbent assay. The 18 DEX and 21 control subjects had similar gestations, birth weights and oxygen requirements at study entry. Lavage VEGF tripled between day 1 and 3 in both groups. The day 7 levels were higher in DEX subjects than in controls. DEX and control values were similar on day 28. Higher lavage VEGF levels on days 1 and 3 were also correlated with lower gestational age at birth. Lavage VEGF levels were not associated with the development of BPD. We speculate that these DEX- and age-associated changes in VEGF may affect pulmonary angiogenesis.
Plasma Arginine Levels and the Response to Inhaled Nitric Oxide in Neonates
Authors: Kavvadia Vasiliki , Greenough Anne , Lilley Julia , Laubscher Bernard , Dimitriou Gabriel , Boa Frances , Poyser Karen 
Published: April 2003

Inhaled nitric oxide (iNO) can be an effective vasodilator in pulmonary hypertension of the newborn (PHN). The aim of this study was to determine whether differences in arginine levels, from which endogenous NO is produced, explain the variability in response to NO and whether the arginine levels were lower in term and preterm infants with PHN than in infants without PHN (controls). We prospectively studied 30 infants (17 born preterm) with clinically diagnosed PHN and treated with iNO and 22 controls (14 born preterm). Three NO levels (10, 20, 40 ppm) were administered to the PHN infants to identify that associated with maximum oxygenation. Twenty-seven infants with PHN improved following iNO and had lower arginine levels than those infants who did not respond to iNO (p < 0.05). No significant relationship, however, was noted between the arginine levels and either the magnitude of change in the oxygenation index in response to iNO or the NO level associated with maximum oxygenation. The median plasma arginine level prior to iNO of the PHN infants was 12.5 (range 2–53) μmol/l, but not significantly lower than that of the controls (median 24, range 3–82 μmol/l). We conclude that differences in plasma arginine levels are unlikely to explain the variation in response to iNO and that, although arginine levels tended to be lower in infants with PHN, this is not a consistent finding in either the term or preterm infants.
Urinary Nitrite Excretion after Prophylactic Intravenous Immunoglobulin in Premature Infants
Authors: Özkan Hasan , Uzuner Nevin , Ören Hale , Çabuk Nur , İşlekel Hüray 
Published: April 2003

<i>Aims:</i> To investigate the correlation between the prophylactic administration of intravenous immunoglobulin (IVIG) to preterm infants and urinary nitrite levels, which can be utilized as an index of endogenous nitric oxide (NO) formation, and to determine if NO formation plays a role in both therapeutic and adverse effects of IVIG. <i>Methods:</i> 28 healthy preterm infants were included in this prospective study. They had a mean gestational age of 29.4 ± 2.2 weeks and weight of 1,387 ± 371 g. Prophylactic IVIG infusion at a dose of 0.5 g/kg/day was administered when they were 3–10 days old. Urine samples of the neonates were obtained for analysis on days 1, 2 and 3 after IVIG administration as well as 1 day before. Urinary nitrite levels obtained in the subjects were normalized for urinary creatinine concentrations. <i>Results:</i> The mean urinary nitrite levels were: 2.77 ± 1.66 μmol/mmol creatinine before IVIG administration; 4.33 ± 3.88 μmol/mmol creatinine on the 1st day of IVIG; 3.77 ± 2.73 μmol/mmol creatinine on the 2nd day, and 3.64 ± 3.28 μmol/mmol creatinine on the 3rd day. There was a significant increase in urinary nitrite levels between before and after IVIG administration. There was no statistical difference in urinary nitrate levels between days 1, 2 and 3 after IVIG administration. <i>Conclusion:</i> We demonstrated that urinary nitrite excretion is significantly elevated in preterm infants after prophylactic IVIG administration and this result suggests that endogenous NO formation may play an important role in both the therapeutic and adverse effects of IVIG.
Endothelin Concentrations in Preterm Infants Treated with Human Recombinant Erythropoietin
Authors: Cogar Allison A. , Hartenberger Carol H. , Ohls Robin K. 
Published: April 2003

<i>Background:</i> Increased endothelin-1 (ET-1) production following recombinant erythropoietin (Epo) administration is a presumed etiology for the hypertension reported in some adults. It is unknown whether Epo has similar effects in preterm infants. <i>Methods:</i> Serum ET-1 and Epo concentrations were measured prior to study, and following the second and third doses in 20 preterm infants receiving intravenous (IV) or subcutaneous (SC) Epo. Blood pressures were monitored prior to Epo administration and during the first, second, and third dose. <i>Results:</i> Infants (963 ± 54 g birth weight, 27.4 ± 0.6 weeks gestational age, 18 ± 3 days of life; mean ± SEM) had baseline Epo concentrations of 5.5 ± 1.3 mU/ml and ET-1 concentrations below the lower limits of detection (<1 pg/ml). Epo concentrations were 1,848 ± 274 and 1,672 ± 295 mU/ml following the second and third IV dose, respectively, while Epo concentrations were 420 ± 92 and 290 ± 35 mU/ml after the second and third SC dose, respectively (p < 0.005, SC versus IV). ET-1 concentrations remained below the limits of detection in all but 6 infants, whose concentrations were <3.3 pg/ml. Blood pressures did not increase above baseline in either group during the study period. <i>Conclusion:</i> Despite the wide range of Epo concentrations measured, no correlation was observed between Epo concentrations, ET-1 concentrations, and blood pressure during the 1-week study period. The long-term effects of Epo on ET-1 concentrations and blood pressure in preterm infants require further study.