Standard hypothyroid treatment did not restore proper metabolic response to carbohydrate.

Purpose: Hypothyroidism is associated with a lower metabolic rate, impaired glucose tolerance, and increased responsiveness of sympathetic nervous system to glucose ingestion. The Levothyroxine (LT4) monotherapy is the standard treatment for hypothyroidism; however to what extent this treatment restores the patients' metabolism has not been verified. The aim of this study was to test the hypothesis that standard LT4 therapy may not restore proper metabolic response to carbohydrate ingestion.

Doppler imaging of orbital vessels in the assessment of the activity and severity of thyroid-associated orbitopathy.

Patients with symptoms of thyroid-associated orbitopathy are classified on the basis of the clinical activity score (CAS) proposed by Mourits in 1989. Despite its undoubted clinical usefulness, it has several limitations which can decide about the success or failure of the implemented treatment. Numerous reports mention the presence of hemodynamic changes in orbital and bulbar vessels in the course of an orbitopathy called Graves' disease.

Thermogenic effect of glucose in hypothyroid subjects.

The importance of thyroid hormone, catecholamines, and insulin in modification of the thermogenic effect of glucose (TEG) was examined in 34 healthy and 32 hypothyroid subjects. We calculated the energy expenditure at rest and during oral glucose tolerance test. Blood samples for determinations of glucose, plasma insulin, adrenaline (A), and noradrenaline (NA) were collected.

Enteral feeding during indomethacin and ibuprofen treatment of a patent ductus arteriosus.

Objective: To test the hypothesis that infants who are just being introduced to enteral feedings will advance to full enteral nutrition at a faster rate if they receive "trophic" (15 mL/kg/d) enteral feedings while receiving indomethacin or ibuprofen treatment for patent ductus arteriosus.

Study Design: Infants were eligible for the study if they were 23(1/7)-30(6/7) weeks' gestation, weighed 401-1250 g at birth, received maximum enteral volumes ≤60 mL/kg/d, and were about to be treated with indomethacin or ibuprofen. A standardized "feeding advance regimen" and guidelines for managing feeding intolerance were followed at each site (N = 13).

Hypothermia for hypoxic-ischemic encephalopathy.

We are entering an era in which hypothermia will be used in combination with other novel neuroprotective interventions. The targeting of multiple sites in the cascade leading to brain injury may prove to be a more effective treatment strategy after hypoxic-ischemic encephalopathy in newborn infants than hypothermia alone.

Variables associated with the early failure of nasal CPAP in very low birth weight infants.

Objective: To identify risk factors and neonatal outcomes associated with the early failure of "bubble" nasal continuous positive airway pressure (CPAP) in very low birth weight (VLBW) infants with respiratory distress syndrome (RDS).

Study Design: Following resuscitation and stabilization at delivery, a cohort of 261 consecutively inborn infants (birth weight < or = 1250 g) was divided into three groups based on the initial respiratory support modality and outcome at 72 hours of age: "ventilator-started" group, "CPAP-failure" group, and "CPAP-success" group.

Results: CPAP was successful in 76% of infants < or = 1250 g birth weight and 50% of infants < or = 750 g birth weight.

Factors associated with microcephaly at school age in a very-low-birthweight population.

The neonatal predictors of microcephaly, defined as a head circumference <5th centile in children born preterm, has not been systematically assessed. Children were drawn from the Developmental Epidemiology Network (DEN) cohort of very low-birthweight children (VLBW: 500-1500g) born from 1991 to 1993 at three sites in the USA. Neurological assessments were carried out among 198 singleton children (mean age 6 years 8 months, SD 0.

Systemic hypotension and white-matter damage in preterm infants.

This study was designed to test the hypothesis that systemic hypotension during the first postnatal week increases the risk of ultrasonographic echolucency in the white matter of preterm infants (< or = 28 weeks' gestation) while adjusting for confounders. From a study base of 1607 very-low-birthweight neonates (500 to 1500 g), a subsample of 243 preterm infants (122 females; < or = 28 weeks' gestation) was selected for echolucency and data collection prospectively for the entire first postnatal week. Data analyses were performed separately for the first 24 hours of life, for the interval from the end of the first 24 hours to the end of the fourth postnatal day, and for days 5, 6, and 7.

Risk of cranial ultrasound abnormalities in very-low-birth-weight infants conceived with assisted reproductive techniques.

Objective: To evaluate risks of cranial ultrasound abnormalities among very-low-birth-weight (VLBW) infants conceived with fertility therapy (ovulation induction only or with assisted reproductive techniques [ART]) and of multiple gestation pregnancies.

Study Design: The incidences of cranial ultrasound abnormalities in 1473 VLBW infants conceived with and without fertility therapy and born of multiple versus singleton pregnancies were compared, using logistic regression models.

Results: Infants conceived with ART were less likely to have intraventricular hemorrhage (IVH).

Topography of cerebral white-matter disease of prematurity studied prospectively in 1607 very-low-birthweight infants.

The objective of this study was to evaluate to what extent (1) the characteristics of localization, distribution, and size of echodense and echolucent abnormalities enable individuals to be designated as having either periventricular hemorrhagic infarction or periventricular leukomalacia and (2) the characteristics of periventricular hemorrhagic infarction and periventricular leukomalacia are independent occurrences. The population for this study consisted of 1607 infants with birthweights of 500 to 1500 g, born between January 1991 and December 1993, who had at least one cranial ultrasound scan read independently by at least two ultrasonographers. The ultrasound data collection form diagrammed six standard coronal views.

Do clinical markers of barotrauma and oxygen toxicity explain interhospital variation in rates of chronic lung disease? The Neonatology Committee for the Developmental Network.

Objective: To explore the hypothesis that variation in respiratory management among newborn intensive care units (NICUs) explains differences in chronic lung disease (CLD) rates.

Design: Case-cohort study.

Setting: NICUs at 1 medical center in New York (Babies' and Children's Hospital [Babies']) and 2 in Boston (Beth Israel Hospital and Brigham and Women's Hospital [Boston]).

Maternal infection, fetal inflammatory response, and brain damage in very low birth weight infants. Developmental Epidemiology Network Investigators.

Echolucent images (EL) of cerebral white matter, seen on cranial ultrasonographic scans of very low birth weight newborns, predict motor and cognitive limitations. We tested the hypothesis that markers of maternal and feto-placental infection were associated with risks of both early (diagnosed at a median age of 7 d) and late (median age = 21 d) EL in a multi-center cohort of 1078 infants <1500 x g. Maternal infection was indicated by fever, leukocytosis, and receipt of antibiotic; fetoplacental inflammation was indicated by the presence of fetal vasculitis (i.

White matter disorders of prematurity: association with intraventricular hemorrhage and ventriculomegaly. The Developmental Epidemiology Network.

Objectives: Because intraventricular hemorrhage (IVH) often precedes the development of sonographically defined white matter damage (WMD) in very preterm infants, we sought to identify the IVH characteristics that predict WMD.

Hypotheses: We evaluated variations on the null hypothesis that infants with IVH are no more likely than infants without IVH to have WMD. These variations dealt with characteristics of the IVH (presence or absence of ventriculomegaly) or characteristics of the WMD (size, localization, and laterality).

Maternal receipt of magnesium sulfate does not seem to reduce the risk of neonatal white matter damage.

Objective: To investigate whether in utero exposure to magnesium sulfate is associated with a lower incidence of cranial ultrasonographic abnormalities that predict cerebral palsy in infants who weigh less than 1501 g at birth.

Design: For a prospective study of the antecedents of cranial ultrasonographic abnormalities, we enrolled infants who weighed 500 to 1500 g when born at five institutions. Data were collected by interview of the mothers and review of medical records.

Autoresuscitation: a survival mechanism in piglets.

Piglets were studied to determine 1) the cardiovascular and neurophysiological effects of prolonged laryngeal-induced respiratory inhibition (n = 7) and 2) whether these effects were modulated by autonomic blockade (n = 6). Respiration, electrocardiogram, electroencephalogram (EEG), and blood pressure were recorded, and blood gases were measured. During continuous laryngeal stimulation in the presence of light anesthesia, apnea was interrupted every 1-2.

Cardiovascular and neurophysiologic changes during graded duration of apnea in piglets.

To examine the interrelationship between the duration of apnea and changes in oxygen saturation, blood pressure, electroencephalogram (EEG), and heart rate, reflex apnea of 10, 20, 40, and 60 s duration was induced by stimulating the superior laryngeal nerves. Piglets (n = 11, age 5-14 days) were chronically instrumented for continuous monitoring of SaO2 and blood pressure and for sampling arterial blood. Ventilation was recorded using whole body plethysmography and EEG and electrocardiogram were measured by acutely placed subcutaneous electrodes.

An analysis of the variability in estimates of bioenergetic variables in preterm infants.

Estimates of average daily energy expenditure and minimal observed oxygen consumption are commonly used to characterize the energy metabolism of neonates. Yet, the errors inherent in these estimates have not been defined. Using measurements of oxygen consumption and carbon dioxide production made in healthy growing low birth weight infants during eight consecutive 3-h interfeeding epochs, we have determined the variability in the mean oxygen consumption, carbon dioxide production, respiratory quotient, total daily energy expenditure, and the minimal observed oxygen consumption among the feeding epochs.

Vasopressin concentration in amniotic fluid as an index of fetal hypoxia: mechanism of release in sheep.

Hypoxia is a potent stimulus to the release of vasopressin in fetal sheep, and plasma concentrations of the hormone correlate inversely with fetal oxygenation. Since the fetal kidney contributes to vasopressin clearance, we propose that measurement of increased amounts of vasopressin in amniotic fluid would be indicative of fetal hypoxia. Therefore, we measured concentrations of vasopressin in amniotic fluid under resting conditions, during and after fetal hypoxia, and with intravenous and intra-amniotic administration of vasopressin in 15 chronically instrumented fetal lambs between 111 and 141 days gestation.

Vasopressin concentration in amniotic fluid as an index of fetal hypoxia: mechanism of release in sheep.

Hypoxia is a potent stimulus to the release of vasopressin in fetal sheep and, in turn, plasma concentrations of the hormone correlate inversely with fetal oxygenation. Because the fetal kidney contributes to vasopressin clearance, we propose that measurement of increased amounts of vasopressin in amniotic fluid would be indicative of fetal hypoxia. We therefore measured concentrations of vasopressin in amniotic fluid under resting conditions, during and after fetal hypoxia, and with intravenous and intra-amniotic administration of vasopressin in 15 chronically instrumented fetal lambs 111-141 d gestation.

Excretion of vasopressin in the hypoxic lamb: comparison between fetus and newborn.

The factors associated with increased renal excretion of vasopressin (VP) were examined in the hypoxic fetus and newborn. Studies were conducted on six chronically instrumented fetal (117-136 days gestation) and seven newborn lambs (2-6-day-old). Hypoxia was produced by administration of 10% oxygen to the ewe or neonate for 30 min.

Vasopressin secretion induced by hypoxia in sheep: developmental changes and relationship to beta-endorphin release.

To investigate the developmental changes in the secretion of vasopressin and the potential role of beta-endorphin as a stimulus to the release of vasopressin, the concentrations of these peptides were measured in fetal, newborn, and adult sheep after episodes of induced hypoxia. The studies confirm that hypoxia is a potent stimulus to the release of both vasopressin and beta-endorphin in the fetal animal. In both the newborn lamb and the ewe, more profound hypoxia is necessary for a similar release.