Biomedical subjects

D Bader

Publications and source records attributed to D Bader.

At least 19 recordsLinked to original sources

PubMed2006

Cardiac troponin I serum concentrations in newborns: a study and review of the literature.

BACKGROUND: Serum cardiac troponin I (cTnI) is a specific marker of cardiac injury. The use of cTnI in neonates, especially in relation to perinatal asphyxia has not been extensively examined. We defined the range of normal values of cTnI in newborns, and study factors that may influence these concentrations. METHODS: Serum cTnI concentrations were measured on the third day of life in 179 normal newborns: 157 were term (after 37 weeks, mean: 39.7+/-1.1, range: 37-42) and 22 were premature infants (mean: 32.6+/-2.9, range: 27-36 weeks). RESULTS: Mean cTnI for the term infants was 0.63+/-0.58 ng/ml (median: 0.50, range: 0.00-4.30). The concentration of 1.80 ng/ml, can serve as the upper limit of normal values. There was a borderline significant trend for higher cTnI in preterm infants. The number of newborns with cTnI>1.80 ng/ml was significantly higher after delivery by caesarean section, compared to vaginal delivery (14.6% vs. 2.9%, p<0.02). No other significant associations were found between cTnI and perinatal or neonatal parameters. CONCLUSIONS: Normal reference values for cTnI in healthy term newborns were defined, but need to be addressed with caution due to the wide range of normal values.

Biomarkers↗

PubMed2006

Hood versus mask nebulization in infants with evolving bronchopulmonary dysplasia in the neonatal intensive care unit.

OBJECTIVE: To compare infants' discomfort, nursing-time and caregiver preference, and assess the clinical efficiency (as a secondary outcome) of hood versus facemask nebulization in infants with evolving bronchopulmonary dysplasia (BPD) in the neonatal intensive care unit. STUDY DESIGN: A prospective, open, randomized, controlled crossover clinical trial. In total, 10 infants with BPD who were on inhaled beta-agonist bronchodilators and corticosteroids were randomly assigned to receive their nebulized treatments either by a facemask, or by a hood for 2-3 days, and then crossover to receive the same treatments with the other technique for another 2-3 days. Infants' discomfort, nursing-time, caregiver preference and clinical efficiency were compared. RESULTS: At baseline there was no significant clinical difference between the groups. Nurse-time required for administering the hood nebulization (mean+/-s.e.m.: 1.9+/-0.1 min) was significantly shorter than the time for mask nebulization (12.0+/-0.6 min, P<0.0001). Infants' discomfort score was significantly lower (0.1+/-0.04) for hood versus mask nebulization (2.5+/-0.2, P<0.0001). Nurses and parents unequivocally preferred the hood treatment. During both mask and hood nebulization therapies (2-3 days) clinical efficiency was comparable. While both methods caused an immediate (20 min post) clinical improvement, the immediate respiratory assessment change score was significantly greater for the hood versus the mask nebulization (0.62+/-0.27 versus 0.13+/-0.14, P<0.05). CONCLUSIONS: Nebulization of aerosolized medications in infants with evolving BPD by hood was less time-consuming for caregivers and was much better tolerated by the infants while being at least as effective as the conventional facemask nebulization.

Administration, Inhalation↗

PubMed2004

Alpha-fetoprotein in the early neonatal period--a large study and review of the literature.

BACKGROUND: Alpha-fetoprotein (AFP) is a glycoprotein molecule, which has similarity to albumin and is produced by the fetal liver. Its biological role is unclear and factors that may influence its concentrations in neonates are only partially identified. However, it has an important role as a diagnostic marker, especially in certain tumors and liver diseases of childhood. Its normal reference values in newborns have not been well defined. METHODS: Serum AFP concentrations were measured and characterized in 260 term and near-term newborns [gestational age (GA)> or =34 weeks, birthweight (BW)> or =1700 g] at birth [umbilical cord (UC) blood] and upon discharge from the nursery at 60+/-24 h of life (venous sample). RESULTS: Due to the nonnormal distribution of AFP levels, it is useful to relate to reference interval for AFP concentrations at birth that was 15.7-146.5 microg/ml, based on 95% confidence interval (CI). The median value of 48.3 microg/ml is also a useful reference. However, mean AFP concentrations at birth that were 61.6+/-44.8 microg/ml are less informative due to the large standard deviation (S.D.). Upon discharge, AFP concentrations dropped to 9.7-111.9 microg/ml (95% CI) with a median of 34.2 microg/ml. A significant negative correlation was found between AFP serum levels and gestational age and to a lesser extent with birthweight. No significant differences were found between males and females. CONCLUSIONS: Normal reference intervals for AFP in term and near-term newborns have been defined, but need to be addressed with caution due to the wide range of normal values. AFP levels at birth decrease as gestation advances and the newborn weighs more.

Adult↗

PubMed2004

The role of umbilical cord alpha fetoprotein as a screening tool for neonatal hyperbilirubinemia.

Our aim was to test whether alpha fetoprotein (AFP) might serve as a marker of hepatic immaturity sufficient to predict an increased risk for neonatal hyperbilirubinemia (NHB) in term babies. We checked umbilical cord AFP (UC AFP) levels in 174 healthy full-term infants (male/female ratio 1.26:1) at birth. Bilirubin levels were measured upon discharge from the nursery on day 3 of life (mean, 57 +/- 10 hours of life). Mean UC AFP was 60.2 +/- 45.9 mg/L. UC AFP levels were linearly correlated with subsequent bilirubin levels, and significantly higher bilirubin levels were found in neonates whose UC AFP levels were 100 mg/L or more. Although statistically significant correlation between UC AFP and subsequent NHB exists, UC AFP cannot currently be recommended for use in clinical practice because of its inability to serve as a screening tool for significant NHB in the individual newborn.

Female↗

PubMed2004

Breathing patterns in term infants delivered by caesarean section.

AIM: To compare the breathing patterns of infants born by elective caesarean section to those infants delivered by caesarean section after a failed trial of labour. METHODS: Healthy term infants born by caesarean section were studied. The study group (n = 13) had no trial of labour, whereas infants in the control group (n = 13) failed a trial of labour. Polysomnographic study was performed at 36 h of age. Heart and respiratory rate, type and duration of apnoeas, arterial oxygen saturation and lower limb movements were analysed. RESULTS: Term infants born by elective caesarean section had a shorter duration of pregnancy and weighed less. Their heart rate was faster, they had more mixed apnoeas, and during quiet sleep they had more central apnoeas of longer duration. CONCLUSION: Cardiorespiratory patterns in infants delivered by elective caesarean section are different from those delivered by caesarean section after a failed trial of labour.

Brain↗

PubMed2004

Glucose-6-phosphate dehydrogenase activity in male premature and term neonates.

BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) activity is higher in term neonates than in adults. Some studies have suggested that activity may be even higher in preterm infants. OBJECTIVES: To determine if G6PD activity is higher in preterm than term neonates, and whether higher activity would interfere with diagnosis of G6PD deficiency in premature infants. METHODS: G6PD activity was determined in the first 48 hours after delivery in male premature, term, and near term infants. G6PD deficient neonates were separated, and the remaining premature infants compared with healthy, male, G6PD normal, near term and term neonates. RESULTS: Ninety four premature infants (mean (SD) gestational age 31.9 (3.8) weeks (range 23-36)) were studied. In four, G6PD activity was 0.8-1.8 U/g haemoglobin (Hb), which is clearly in the deficient range with no overlap into the normal range. G6PD activity in the remaining premature infants was significantly higher than in 24 near term and term neonates (gestational age > or = 37 weeks) (14.2 (4.6) v 12.0 (3.8) U/g Hb). Further analysis showed that significance was limited to those born between 29 and 32 weeks gestation, in which group G6PD activity was significantly higher than in those born before 29 weeks gestation, at 33-36 weeks gestation, and > or = 37 weeks gestation. CONCLUSIONS: G6PD activity is higher in premature infants born between 29 and 32 weeks gestation than in term neonates. This did not interfere with diagnosis of G6PD deficiency.

Gestational Age↗

PubMed2003

In the eye of the beholder: how accurate is clinical estimation of jaundice in newborns?

AIM: Hour-specific serum total bilirubin (STB) percentiles have proved useful in predicting which babies will develop significant neonatal hyperbilirubinemia (NHB) requiring intervention. This study investigated whether this assessment could be performed visually instead of by blood test. The aim was to evaluate the ability of experienced clinicians to determine accurately the level of clinical jaundice in neonates by visual means. METHODS: Four neonatologists were asked to estimate the level of bilirubin in a group of 283 term clinically jaundiced infants before discharge from the nursery on day 3 of life. Their clinical estimation was compared with actual measurement of STB from samples drawn simultaneously. RESULTS: Clinical estimation of STB had a high correlation to actual serum bilirubin levels (Pearson's correlation coefficient = 0.682, p < 0.001). CONCLUSION: Clinical impression of jaundice by the eye of an experienced clinician is a reliable method to assess newborns for significant NHB and may diminish the need for universal serum sampling.

Bilirubin↗

PubMed2003

Neonatologists are using much less dexamethasone.

Two historical cohorts (1993-1994 and 2001) of preterm infants ventilated for respiratory distress syndrome were compared. Dexamethasone administration fell from 22% to 6%. Chronic lung disease in survivors rose slightly from 13% to 17%, and mortality fell from 21% to 15% (other causes). The effect of restriction of dexamethasone use on chronic lung disease and mortality remains to be seen.

Birth Weight↗

PubMed2002

Sidestream end-tidal capnometry as related to infant's position and maturation.

UNLABELLED: The objective of this study was to investigate the effect of body position on sidestream, end-tidal carbon dioxide (EtCO2) wave measurements in maturing infants. Sidestream EtCO2 wave patterns were analysed longitudinally in 20 preterm infants (born at > or = 32 wk) at 32-37 wk gestation, and in 39 full-term controls. Capnography measurements included maximal EtCO2, inspired CO2 and frequency of apnoea events (>3 s) in the supine, supine with inclination, side and prone positions. Apnoea frequency decreased during maturation, and was less prevalent in the prone than in the supine and side positions in preterm as well as in term infants (p < 0.05). No clinically significant apnoea episodes were found in our cohort. EtCO2 in term infants was lower than that in preterm infants (p < 0.05) and was not affected by sleep position in the most premature (<33 wk) and in term infants (>36 wk). EtCO2 was higher in the prone position than in supine or side positions in infants between 33 and 35 wk gestation (p < 0.01). CONCLUSION: Short apnoeic episodes decrease during maturation, and are less prevalent in the prone position in maturing infants (32-37 wk). Only modest changes in EtCO2 were recorded in the different positions during maturation.

Birth Weight↗

PubMed2001

Functional tests for the characterization of surfactant protein B (SP-B) and a fluorescent SP-B analog.

Surfactant protein B (SP-B) enhances lipid insertion into the alveolar air/liquid interface upon inhalation. The aim of this study was (i) to apply a palette of tests for a detailed biochemical and biophysical characterization of SP-B and (ii) to use these tests to compare native SP-B with a fluorescent (Bodipy) SP-B analog. The method of labeling was fast and resulted in a covalent fluorophore-protein bond. The ability of both proteins to spread a surfactant film on top of a buffer surface was determined in a spreading tray using the Wilhelmy plate technique to allow detection of alterations in surface tension and calculation of spreading velocities. In a captive bubble surfactometer surface tensions of spread films were measured. Similar biophysical properties were found for both native and Bodipy-labeled SP-B. It is concluded that the combination of tests used allows detection of small differences in structure and activity between the two proteins.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed2001

Surfactant protein B labelled with [(99m)Tc(CO)3(H20)3](+) retains biological activity in vitro..

UNLABELLED: Labelling of the hydrophobic surfactant protein B (SP-B) under non-reducing conditions was achieved with [(99m)Tc(CO)(3)(H2O)(3)](+) prepared according to Alberto et al. (JACS, 1998). The binding of radioactivity was protein-specific, with an overall radiochemical yield of 50%. Gel electrophoresis and Westernblot analyses showed no structural changes of SP-B. Spreading properties and surface activity of (99m)Tc-labelled SP-B in an air/water interface coincided with those of unlabelled SP-B. (99m)Tc-SP-B seems to be a promising agent to observe surfactant spreading under clinical conditions. BACKGROUND: Therapeutic results for surfactant instillation in clinical trials are conflicting. The (99m)Tc-labelling of surfactant would allow to observe its spreading in the lung under clinical conditions. METHODS: [(99m)Tc(CO)(3)(H2O)(3)](+) was prepared as described by Alberto et al. (JACS, 1998). This carbonyl complex was used for the direct labelling of surfactant protein B (SP-B) under non-reductive conditions by direct incubation with SP-B at elevated temperature followed by extraction into CHCl(3)/MeOH. RESULTS: The hydrophobic protein SP-B was labelled with [(99m)Tc(CO)(3)(H2O)(3)](+). An overall radiochemical yield of about 50% was achieved. HPLC-analysis revealed a single radiolabelled species according to UV elution profile of SP-B, supported by paper and size exclusion chromatography. Gel electrophoresis confirmed that the dimer structure of SP-B was preserved. Spreading properties of (99m)Tc-labelled SP-B in an air/water interface coincided with those of unlabelled SP-B. Spreading of radioactivity observed in a glass trough of 26 cm x 27 cm with a gamma camera was completed during the first 7-9 sec after application of (99m)Tc-labelled SP-B. The corresponding decrease of surface tension to 45 mN/m at the peripheral surface tension sensors took 7 sec +/- 2 sec (MEAN +/- STD; n = 3). CONCLUSIONS: Direct and specific (99m)Tc-labelling of the hydrophobic surfactant protein B was achieved using the [(99m)Tc(CO)(3)(H2O)(3)](+) precursor. This procedure can easily be used to prepare specifically labelled surfactant mixtures with spreading properties that coincide with those of unlabelled surfactant.

Animals↗

PubMed2001

The role of high-dose oral iron supplementation during erythropoietin therapy for anemia of prematurity.

OBJECTIVE: To assess whether a high intake of oral iron would increase the effect of recombinant human erythropoietin (rHuEPO) on hemoglobin synthesis. METHODS: We studied 30 preterm infants (gestational age 29+/-1.8 weeks, birth weight 1161+/-200 g, at age of 28+/-10 days) who were randomly assigned to receive either 8 mg/kg per day (n=15) or 16 mg/kg per day of oral iron during a course of rHuEPO therapy (900 microg/kg per week) for a duration of 4 weeks. Both groups were comparable in regard to clinical and laboratory data at the time of enrollment. RESULTS: rHuEPO caused a significant increase in reticulocyte count in the low- and high-dose iron groups, 17.1+/-5.3 to 34.7+/-9.2 and 16.3+/-3.3 to 42.5+/-5.6 (10(9)/l), respectively (p<0.05). However, in both groups, hematocrit values remained stable at the end of the study as compared to baseline (0.35+/-0.03% vs. 0.30+/-0.03%, 0.35+/-0.05% vs. 0.30+/-0.03%, NS) and in both groups there was a comparable and significant decrease in ferritin level (259+/-109 to 101+/-40 and 168+/-54 to 69+/-38 microg/l, respectively; p<0.01). The rates of bloody stools without any evidence of necrotizing enterocolitis were not significantly different between the two treatment groups (1/15 vs. 4/15, NS). CONCLUSION: We conclude that a higher dose (16 mg/kg per day) of oral iron is not more beneficial when compared to a lower dose (8 mg/kg per day) during rHuEPO therapy for anemia of prematurity. Further studies will define the optimal dosage and route of administration of iron supplementation during rHuEPO therapy.

Administration, Oral↗

PubMed2001

Capnography in spontaneously breathing preterm and term infants.

OBJECTIVE: To investigate sidestream EtCO2 wave patterns as related to prematurity. DESIGN: The EtCO2 wave pattern was analyzed longitudinally in 20 sequential preterm, 32-37 weeks of gestation and 39 fullterm controls. Infants with a cardiorespiratory disease, neurological deficit or a metabolic disorder were not included in the study. Sidestream EtCO2 was employed. Wave patterns were identified and baseline expiratory/inspiratory length and wave amplitude were measured. RESULTS: Two predominant (about 75%) wave patterns were identified: (i) (with plateau) significantly more prevalent among infants born at term as compared with preterm infants across their postconceptional ages (PCA) (P=0.005-0.04), (ii) (plateau free) significantly more prevalent among the youngest preterm infants as compared with the fullterm controls. Expiratory length was significantly correlated with respiratory rate (RR) across ages (P=0.01-0.001) whereas inspiratory length was correlated with RR among the two youngest groups of infants only (P=0.002 and 0.004). Wave patterns were not found to be affected by environmental temperatures, blood pressure, body weight, haemoglobin level, aminophylline or O2 supplementation. CONCLUSION: These findings suggest that EtCO2 wave pattern distribution among preterm infants is distinctly different from that of term controls, regardless of PCA, while inspiration is related to the degree of maturity. Alveolar pathology could probably be missed by sidestream capnography.

Blood Pressure↗

PubMed2001

Validation of a specific activity questionnaire to estimate exercise tolerance in patients referred for exercise testing.

BACKGROUND: Physical activity and symptom questionnaires have been used as surrogates for exercise testing to estimate a patient's functional capacity and to individualize an exercise testing protocol in accordance with exercise testing guidelines. To validate these approaches, they must be compared with measured oxygen uptake (peak VO (2)). METHODS: Before exercise testing was performed, a brief, self-administered questionnaire (Veterans Specific Activity Questionnaire [VSAQ]) was given to 337 patients referred for exercise testing for clinical reasons. The VSAQ was used to estimate exercise tolerance on the basis of symptoms during daily activities to individualize ramp rates on the treadmill so that the test duration would be approximately 10 minutes. Clinical and demographic variables were added to the VSAQ responses in a stepwise regression model to determine their ability to predict both directly measured peak VO (2) and peak metabolic equivalents (METs) predicted from the treadmill workload. RESULTS: The mean exercise time was 9.6 +/- 3 minutes. Responses to the VSAQ and age were the strongest predictors of both measured and predicted exercise capacity. Small but significant contributions to the explanation of variance in both measured and estimated METs were made by resting heart rate, forced expiratory volume in 1 second expressed as a percentage of normal, exercise capacity predicted for age, and body mass index. The multiple R values from the regression equations for measured and estimated METs were 0.58 and 0.72, respectively. CONCLUSIONS: Estimating a patient's symptoms associated with daily activities along with age are the strongest predictors of a patient's exercise tolerance. The VSAQ, combined with pretest clinical data, predicts the estimated MET value from treadmill speed and grade better than directly measured METs do. When used for estimating a patient's symptom limits to individualize ramp rates on a treadmill, this approach yields an appropriate test duration in accordance with recent exercise testing guidelines.

Activities of Daily Living↗

PubMed2000

Analysis of CMF1 reveals a bone morphogenetic protein-independent component of the cardiomyogenic pathway.

Disruption of the CMF1 function in anterior mesoderm inhibits cardiac myogenesis in avian embryos. In the present study, we show that CMF1 is a member of an emerging family of proteins that includes centromeric protein-F, mitosin, and LEK1. These proteins are characterized by their large size (350 kDa), dynamic subcellular distribution, and potential functions in cell division and differentiation. The current data suggest that CMF1 is a unique member of this family by virtue of its restricted protein expression and variant subcellular distribution. Immunochemical analysis demonstrates that CMF1 protein is expressed in cardiogenic cells prior to the activation of cardiac structural gene products. In addition, we show that expression of CMF1 is not dependent on the bone morphogenetic protein (BMP) signaling pathway during development. Still, CMF1 cannot direct cardiomyogenesis in the absence of such factors as NKX-2.5. Taken with our previous data, this study suggests that CMF1 is a BMP-independent component of the cardiomyogenic pathway.

Amino Acid Sequence↗

PubMed2000

Identification and genomic cloning of CMHC1. A unique myosin heavy chain expressed exclusively in the developing chicken heart.

We report the identification and cloning of a unique chick myosin heavy chain (CMHC1) that is expressed exclusively in the heart during embryogenesis. Using primers specific to myosin heavy chains, we used reverse transcriptase-polymerase chain reaction to clone and isolate CMHC1 from embryonic day 10 chicken heart RNA. Sequence analysis indicated that CMHC1 was a novel member of the myosin heavy chain family. Expression of the CMHC1 transcripts was detected in Hamburger Hamilton stage 10 chick embryos in the fusing myocardium. Expression of CMHC1 was maintained at high levels throughout the tubular heart of later stage embryos. Reverse transcriptase-polymerase chain reaction and in situ hybridizations failed to detect CMHC1 transcripts in the developing somites, limb buds, or skeletal musculature at any stage of chick development. Genomic CMHC1 clones have been isolated that contain sequences approximately 5.2 kilobase upstream of the presumptive CMHC1 transcription start site. Portions of the upstream regulatory region induced a 21-fold increase in reporter gene expression in primary cardiomyocytes. Because of its unique cardiac-restricted expression, CMHC1 will provide an excellent model system to study the molecular mechanisms required for the early developmental regulation of heart-specific genes.

3T3 Cells↗

PubMed2000

Potential role of high-frequency ventilation in the treatment of severe congenital pleural effusion.

Newborns with severe congenital pleural effusions often present with respiratory failure at birth. We describe two premature infants born at 31 and 33 weeks of gestation with bilateral pleural effusions. Both were drained prior to delivery under ultrasound guidance. The first infant had severe bilateral congenital chylothorax with pulmonary hypertension; the second infant had severe nonimmune hydrops fetalis. Both could be adequately oxygenated but failed to respond to conventional mechanical ventilation (CMV) and chest tube drainage, so that CO(2) elimination could not be accomplished. Both infants were successfully treated with high-frequency ventilation (HFV). We suggest that HFV may be of significant value in establishing adequate ventilation in cases of severe congenital pleural effusions.

Adult↗

PubMed2000

Characterization of CMF1 in avian skeletal muscle.

This study reports the identification of the CMF1 protein in somites and embryonic limb muscle. We have previously described CMF1 in developing cardiac muscle. CMF1 is a member of the LEK family of proteins, which are involved in regulating mitosis. Our current data suggest that CMF1 expressed in skeletal and cardiac myocytes is the product of a single gene and that the two proteins are homologous or very highly conserved. Immunohistochemistry shows a dynamic subcellular localization of CMF1 in differentiating skeletal myoblasts: Early myoblasts stain positively for CMF1 antigen in the nucleus, while differentiating myoblasts stain positively in the cytoplasm. CMF1 expression precedes myosin. Later, CMF1 and myosin are detected in the cytoplasm of the same cells. Transfection analysis identifies a functional nuclear localization signal (NLS) in CMF1, whose nuclear transport capability is modified by external sequences. To characterize the function of CMF1 in skeletal muscle, we used antisense oligonucleotides to disrupt CMF1 in myoblast cultures. Expression of CMF1 in early myotubes is reduced by an average of 40% on a cell by cell basis, with a 56% reduction in anti-myosin staining. These data suggest that CMF1 is involved in induction and/or accumulation of myosin in differentiating myocytes.

Amino Acid Sequence↗