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ABSTRACT. We prospectively assessed and compared the vitamin A status of two groups of preterm neonates (~1 5 0 0 g birth weight, <32 wk gestation), one who developed clinical and radiographic evidence of bronchopulmonary dysplasia (BPD) (n = lo), and the other (control) who developed no significant lung disease (n = 8). The infants with BPD in this study required prolonged mechanical ventilation and supplemental Oz therapy, and had a higher incidence of cardiorespiratory complications when compared to controls. Their mean plasma vitamin A concentrations were significantly lower than those of controls at four sampling times in the 1st postnatal month. In contrast to the controls, infants with BPD showed a substantial decline in their plasma vitamin A concentrations from the initial values, and a high percentage of individual values of plasma vitamin A concentration in these infants were

OBJECTIVE:We tested the hypothesis that creamatocrit, the length of the cream column separated from milk by centrifugation and expressed as a percentage of the length of the total milk column, is a useful measure of the lipid concentration and the energy content of human milk. STUDY DESIGN:Milk samples from 17 mothers of preterm infants were analyzed prospectively, fresh as well as frozen and thawed, for creamatocrit measurement and nutrient composition. RESULTS:Creamatocrit correlated strongly with lipid concentration and energy content of human milk, fresh or frozen and thawed. The energy content can be calculated from the regression equation: Energy (kcal/dl) ϭ 5.99 ϫ creamatocrit (%) ϩ 32.5 for a fresh sample, and energy (kcal/ dl) ϭ 6.20 ϫ creamatocrit (%) ϩ 35.1 for a frozen sample. CONCLUSION:Calculations of energy content from the creamatocrit measurement may be useful for an accurate assessment of energy intake in preterm infants fed human milk.Human milk often is fortified with additives in the nutritional management of preterm infants. Because of the marked variation in the nutrient composition of human milk, 1 the precise energy content of the fortified milk remains unknown. Creamatocrit, the length of the cream column separated from milk by centrifugation and expressed as a percentage of the length of the total milk column, varies with the lipid concentration of milk. 2 We hypothesized that the creamatocrit is a useful measure of the lipid concentration, and hence, of the energy content of human milk. Human milk often is frozen for storage and later thawed before feeding preterm infants. We hypothesized that the freezing and thawing of human milk does not alter the validity of the creamatocrit measurement. To test both these hypotheses, we performed a prospective analysis of human milk, fresh as well as frozen and thawed, for its creamatocrit measurement and nutrient composition. METHODS SamplesWe collected freshly expressed human milk samples from mothers of preterm infants who were hospitalized in the neonatal intensive care unit at Vanderbilt University Medical Center. The study was approved by the Committee for the Protection of Human Subjects-Health Sciences of the Institutional Review Board of Vanderbilt University, and informed consent was obtained from each mother.Each milk sample was mixed well and divided into two aliquots, a fresh aliquot for immediate analysis, and a second aliquot, which was placed in a freezer at Ϫ20°C for 7 days and then thawed at 37°C before analysis. Each aliquot was analyzed for creamatocrit, and for concentrations of lipid, carbohydrate, and protein. Creamatocrit MeasurementA hematocrit centrifuge (International Equipment Co.; Needham Heights, MA), glass capillary tubes (32 ϫ 0.8 mm) (Drummond Scientific Company, Broomall, PA), and a microhematocrit reader (Drummond) were used for the measurement of creamatocrit as described previously.3 Milk was drawn by suction into capillary tubes from a well-mixed sample. The tubes were sealed at one end with clay (Chase Instr...

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SummaryThis study assessed and compared the plasma and red blood cell concentrations of carnitine in cord blood samples from preterm (a36 wk, n = 53) and term (237 wk, n = 72) neonates. The mean (+S. Carnitine, ,8-OH-y-trimethyl amino-butyric acid, is a quarternary amine that plays an essential role in the oxidation of long chain fatty acids by facilitating their transport across the inner mitochondria1 membranes via a carnitine acyltransferase enzyme system (8, 16). Improved fatty acid utilization would enhance a neonate's ability to utilize energy, which in turn may potentiate growth. Fatty acid oxidation also plays an important part in the thermogenic function of brown adipose tissue (10). This factor may be of an immense value to the neonate, particularly a sick preterm infant in achieving thermal homeostasis. Animal studies have suggested an important role for carnitine in hepatic ketogenesis (12). Ketones constitute a significant source of metabolic fuel, particularly for utilization by brain in the perinatal period (18). These various studies seem to indicate that carnitine is one of the essential nutrients in the diet of newborn infants (3).EStudies in various animal species have demonstrated a transfer of carnitine from the mother to the fetus during pregnancy and via milk during the postnatal period (10,11,20). The amount of carnitine transferred across the placenta varies with different species. Little is known of carnitine levels during various stages of human gestation. Plasma concentration of carnitine is often used as the parameter for determination of carnitine status. This study was designed to assess and compare the plasma concentrations of carnitine at birth in a group of preterm and term neonates. Additional assessment of RBC concentrations of carnitine in the same group of infants was also undertaken. MATERIALS AND METHODSSubjects: Fifty-three preterm infants, admitted to the neonatal intensive care unit at the Vanderbilt Medical Center, were studied. These infants (male = 30 and female = 23) were a36 wk gestation. Their birth weights ranged 790-3010 g. Fourteen of these infants were 530 wk gestation and had a mean ( f S.E.) birth weight of 1100 f 48 g. Nineteen infants were 31-33wk and weighed 1620 + 54 g. Twenty infants were 34-36 wk in gestation and weighed 2360 f 75 g at birth. Of these 53 preterm infants, 35 were born to caucasian parents; the remainder with the exception of two Oriental infants were born to black parents. Of the 53 preterm infants, 18 were delivered by cesarean section; the remainder were delivered vaginally. The common indications for abdominal delivery were prematurity and breech presentation. All infants were AGA as their body measurements were within f 2.0 S.D. of the mean on standard growth graphs (1).Sixty-three term infants at the Vanderbilt Medical Center were studied concurrently. These infants (male = 3 1 and female = 32) were 537 wk gestation. Their birth weights ranged 2810-41 10 g (mean + S.E., 3390 + 47 g). Of the 63 term infants, 45 were born to caucasia...

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We examined the ontogeny of vitamin A storage in fetal and neonatal lungs during perinatal development in the rat. High-performance liquid chromatography was used to measure concentrations of vitamin A and its esters, retinyl palmitate and stearate, in various fetal and neonatal tissues at times ranging from gestational day 14 through 21 and from postnatal day 1 through 21. The data show that significant vitamin A storage occurs in the fetal lung during the latter one-third of prenatal life. Depletion of these stores that begins before birth and continues into the early postnatal period suggests that the developing lung may be dependent on these local vitamin A stores during active growth and differentiation. The utilization of vitamin A stores in the developing lung appears to be independent of the liver stores of vitamin A.

ABSTRACT. This study assessed the liver vitamin A concentrations at birth in a group of very low birth weight neonates (n = 25) ( Recent studies have shown that the plasma concentrations of vitamin A (retinol) and RBP at birth are lower in neonates of preterm gestation than in infants born at term (1-3). Estimation of the vitamin A content of the liver is believed to be a more accurate indicator of the vitamin A status than the plasma concentrations of vitamin A or RBP (4, 5). This study was designed to assess the liver vitamin A reserves at birth in a group of VLBW neonates dying within 24 h of birth, prior to possible changes in vitamin A status induced by postnatal nutritional manipulation or therapeutic intervention. MATERIALS AND METHODSSubjects. Liver tissue samples were obtained at autopsy from 25 neonates who died in the neonatal intensive care unit at Vanderbilt Medical Center. These infants (male = 14, female = 11) were 16-32 wk gestational age (mean f SD; 25.6 + 3.5 wk) Eighteen infants were born within the hospital; the remainder were transferred from other hospitals within 4 h of birth. Eighteen infants were white; the remainder were black. None of the infants had congenital anomalies or evidence of intrauterine growth retardation. Death was secondary to complications of extreme prematurity and occurred within 24 h of birth in all cases. Massive intraventricular hemorrhage was the predominant cause of death. None of the infants received exogenous vitamin A during their brief postnatal life.Autopsyprocedures. Permission for a full autopsy was obtained from the parents in each case. The autopsy was performed within 12 h of death in all cases. Liver vitamin A concentrations are reported to remain unchanged in autopsy specimens for long periods, even after partial tissue autolysis (4). Liver tissue was obtained from the central portion of the right lobe. This portion was selected for analysis as it best reflects values for vitamin A concentration obtained from whole liver homogenates (6). The tissue was placed in a labeled, tightly capped plastic container protected from direct light and frozen at -20" C until analysis. The analyses were performed within 2 wk of obtaining each sample. Storage for an extended period of time at below O" C temperatures has been shown to cause no alteration in the tissue vitamin A content (7). A blood sample was collected from 16 of these infants at autopsy by direct cardiac puncture. The serum was separated from each sample by centrifugation and stored at -20" C until analysis. concentrations of liver vitamin A, serum vitamin A, and serum RBP showed no significant differences with respect to sex or race, nor did they correlate significantly with gestational age or birth weight. Linear regression analysis did not show a significant Chemical procedures. Serum vitamin