Maurizio Amato

Regional Metabolic Assessment of Human Brain during Development by Proton Magnetic Resonance Spectroscopy In Vivo and by High-Performance Liquid Chromatography/Gas Chromatography in Autopsy Tissue

To study the course of regional metabolite concentrations during early brain development, we measured in vivo metabolites [N-acetyl-aspartate (NAA), choline-containing compounds, and myo-inositol (M-Ino)] in the precentral area of the cerebrum by short echo-time single volume proton magnetic resonance spectroscopy and compared in vivo established spectroscopic data with classic chromatographic data (HPLC) on age-corresponding autopsy tissue in different regions of the brain. In autopsy tissue, regional (frontal lobe, precentral area, basal ganglia, thalamus) and age-dependent differences of the concentration of creatine, NAA, and M-Ino were determined. In vivo measurement of NAA by proton magnetic resonance spectroscopy shows a significant increase of NAA by increasing postconceptional age. M-Ino shows a weak correlation and a nonsignificant decrease with increasing postconceptional age. Choline shows no age-dependent changes. Creatine concentrations measured by HPLC in different regions of the developing brain at autopsy showed an age-dependent increase that was identical for the left and right side and similar for the precentral area and frontal lobe and more pronounced for the basal ganglia and thalamus. Comparison of the results obtained by the two methods shows agreement for the age-dependent changes and the absolute concentration of M-Ino. NAA determined in autopsy tissue by HPLC is significantly lower than that measured in vivo by proton magnetic resonance spectroscopy. A comparison of the concentrations measured by HPLC in frontal lobe, basal ganglia, and thalamus with the results obtained from the precentral area showed significant regional differences in all measured metabolites. These results define important age-dependent changes detected with both methods and further indicate limitations of both methods that have to be considered when presenting absolute concentration values.

Cytokines in Human Colostrum and Neonatal Jaundice

Breast-fed infants have higher bilirubin levels than formula-fed infants, possibly because of variations in the composition of the breast milk. The aim of this study was to investigate whether there is a relationship between cytokine levels in the colostrum of nursing mothers and neonatal jaundice (NJ). Breast milk samples were collected from breast-feeding mothers of healthy full-term neonates, 32 with NJ and 29 without jaundice. The concentrations of IL-1β, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF)-α were measured by chemiluminescence enzyme immunometric assays. Mothers of infants with NJ had a higher concentration of IL-1β in colostrum, compared with those feeding neonates without NJ, and similar trends were seen for IL-6, IL-8, IL-10, and for TNF-α. The concentrations of IL-1β significantly correlated with IL-6, IL-8, IL-10, and TNF-α concentrations, but not with serum bilirubin levels of infants with NJ. In conclusion, the concentrations of IL-1β were increased in colostrum from breast-feeding mothers whose infants had NJ. The correlation between the concentrations of cytokines involved in the function of hepatic uptake and excretory systems and in the enterohepatic circulation of bilirubin provides additional data to the delineation of the cascade of pathophysiological events that can lead to NJ.

Rapid biometric assessment of gestational age in very low birth weight infants

Foot length and intermamillary distance were compared to gestational age assessment using obstetrical dates, physical criteria of Ballard score and the evaluation of the anterior vascular capsule of the lens (IPM). Thirty-eight healthy and appropriate for gestational age preterm infants (30 +/- 2.4 weeks) with a birth weight of 1280 +/- 410 g were studied. Internipple distance (IM) and foot length (FL) were measured with a sliding caliper graduated in millimeters. Results were analyzed using the linear regression analysis. Obstetrical dates, physical Ballard score and IMP correlated significantly with both biometric measurements. Mean IM was 58.5 +/- 8.5 mm (range: 45 mm-89 mm) and mean FL was 60.6 +/- 7.9 mm (range: 45 mm-75 mm). The data indicate that the appropriate use of biometric parameters in the early postnatal period can be used to improve assessment of gestational age in VLBW infants.

Effect of Exogenous Surfactant on the Development of Surfactant Synthesis in Premature Rabbit Lung

Surfactant replacement is an effective therapy for neonatal respiratory distress syndrome. Full recovery from respiratory distress syndrome requires development of endogenous surfactant synthesis and metabolism. The influence of exogenous surfactant on the development of surfactant synthesis in premature lungs is not known. We hypothesized that different exogenous surfactants have different effects on the development of endogenous surfactant production in the premature lung. We treated organ cultures of d 25 fetal rabbit lung for 3 d with 100 mg/kg body weight of natural rabbit surfactant, Survanta, and Exosurf and measured their effects on the development of surfactant synthesis. Additional experiments tested how these surfactants and Curosurf affected surfactant protein (SP) SP-A, SP-B, and SP-C mRNA expression. Surfactant synthesis was measured as the incorporation of 3H-choline and 14C-glycerol into disaturated phosphatidylcholine recovered from lamellar bodies. Randomized-block ANOVA showed significant differences among treatments for incorporation of both labels (p < 0.01), with natural rabbit surfactant less than control, Survanta greater than control, and Exosurf unchanged. Additional experiments with natural rabbit surfactant alone showed no significant effects in doses up to 1000 mg/kg. Survanta stimulated disaturated phosphatidylcholine synthesis (173 ± 41% of control;p = 0.01), increased total lamellar body disaturated phosphatidylcholine by 22% (p < 0.05), and increased 14C-disat-PC specific activity by 35% (p < 0.05). The response to Survanta was dose-dependent up to 1000 mg/kg. Survanta did not affect surfactant release. No surfactant altered the expression of mRNA for SP-A, SP-B, or SP-C. We conclude that surfactant replacement therapy can enhance the maturation of surfactant synthesis, but this potential benefit differs with different surfactant preparations.

Lung Disease and Brain Development

With the technical progress made in fetal and neonatal intensive care, perinatal mortality has decreased by 25% over the last decade and has expanded the surviving premature population. Prematurity drastically changes the environment of the developing organism. Striking evidence from a number of disciplines has focused attention on the interplay between the developing organism and the circumstances in which it finds itself. The environmental event during a sensitive period in development, induces injury and/or biological adaptations that lead to altered differentiation of tissues. The organism can express specific adaptive responses to its environment which include short-term changes in physiology as well as long-term adjustments. This review addresses these short-term as well as longer-term changes occurring in lung and brain tissue and illustrates how these changes can be studied using advanced imaging techniques such as magnetic resonance imaging (MRI).

Cerebral blood flow velocity in term infants treated with phototherapy

The relationship between phototherapy and changes in the cerebral circulation was studied in 50 jaundiced newborn infants. The aim of the study was to determine whether important alterations in cerebral hemodynamic occur under blue light therapy. Blood flow velocity, i.e., the pulsatility index (PI) and the area under the velocity curve (AUVC), was measured in the anterior cerebral arteries (ACA) using a Duplex scan technique. No prominent changes compromise flow in the ACA. PI and AUVC values were similar during and after phototherapy (p greater than 0.5) suggesting effective cerebral autoregulation in term infants undergoing light treatment for hyperbilirubinemia.

CONGENITAL HAEMOLYTIC ANAEMIA IN A LOW BIRTH WEIGHT INFANT DUE TO CONGENITAL STOMATOCYTOSIS

Abstract: A baby girl born at 31 weeks gestation showed severe haemolytic anaemia and hyperbilirubinaemia which led to exchange transfusion within the first 12 hours of life. There was no blood group incompatibility between mother and child but there was a marked stomatocytosis of the babys red blood cells. Family history revealed a congenital stomatocytosis in the mother. Biochemical characterization of the defect was performed. Phospholipid analysis of the erythrocyte membrane of mother and child showed an increase in phosphatidylserine with a compensatory decrease in phosphatidylcholine and phosphatidylethanolamine. SDS‐electrophoresis showed multiple modifications of the protein pattern with a decrease in band 6, an increased content of band 4.lb, a slight decrease in band 7 and a clear change in the shape of the protein band 3 pattern. The results suggest that the basis of the observed abnormalities is a common defect in protein posttranslational modification, rather than multiple genetic defects in the synthesis of several proteins. Haematologic, biochemical and clinical course of the disease in this preterm infant are discussed.

Biochemical timing of peri-intraventricular hemorrhage assessed by perinatal CPK-BB isoenzyme measurements

Precise diagnosis of peri-intraventricular hemorrhage (PIVH) requires brain real-time ultrasound imaging procedure (US). However, maximal diagnostic efficiency of US lies between day 4 and 14 since fresh blood may initially appear sonolucent. Because of this supposed interval required for clot formation to become visible on US, serum CPK-BB estimations were performed in the first 60 hours of life to determine precise biochemical timing of PIVH. A group of 50 preterm infants less than 1500 g birth weight (1120 +/- 320 g) and 34 weeks gestation (30 +/- 3.7 weeks) was studied. Serial CPK-BB measurements were performed in serum immediately after birth (T0), then serially at time T1 (6-10 h), T2 (20-30 h), T3 (40-60 h). The incidence of PIVH diagnosed on the third day of life was 30%. Total CPK-BB values at T0 in infants who developed PIVH were significantly higher than those of patients without cerebral bleeding (70.8 +/- 30.5 vs 20.9 +/- 10.7 U/l) (p less than 0.05). The same statistically significant results were not observed analysing the CPK-BB values at T1, T2 and T3. These results suggest that most pathological conditions responsible for enzyme release occur in the pre- or perinatal period.

Ethamsylate and Lung Permeability in Ventilated Immature Newborn Rabbits

The leakage of proteins in the immature neonatal lung can reduce the effect of exogenous surfactant. The effect of ethamsylate, a more specific prostaglandin inhibitor than indomethacin and aspirin-like drugs, on alveolar albumin leak was studied in a group of 27 immature newborn rabbits (gestational age 27 days). A pilot study was carried out using 4 animals and low-dose ethamsylate (10 mg/kg). A second group of animals (n = 12) received at birth, by intravenous injection, ethamsylate (50 mg/kg) and 10% human albumin (7 ml/kg). Animals not receiving ethamsylate (n = 11) served as control group. After 30 min of artificial ventilation with standard tidal volume (10 ml/kg) the lungs were lavaged and the amount of human albumin in lung lavage fluid was determined by immunodiffusion. No statistically significant differences were found in lung-thorax compliance and vascular to alveolar albumin leak between ethamsylate-treated animals and controls (p > 0.5). However, there was a statistically significant negative correlation between protein leak and lung compliance (r = -0.41; p < 0.04). These results suggest no direct influence of early ethamsylate administration on neonatal lung permeability in the immature neonate confirming that lung permeability is inversely related to compliance.

Perinatal hip assessment in very low birth weight infants

Fifty healthy low birth weight infants (<1500 g) without risk factors for congenital hip dysplasia (CHD) were examined by ultrasonography (100 hips) at 40 weeks corrected age and controlled at 3 months postnatal age. Sonographic assessment was performed using the classification of Graf. A physiological delay of hip maturation was observed in 10% of the patients (type IIa). At follow-up all of them had normal hip morphology without any pathological finding. Our results suggest that prematurity alone should not be considered a risk factor for CHD.