Acylcarnitine profiles of preterm infants over the first four weeks of life

Measurement of free carnitine and acylcarnitines allows the detection of several inborn errors of metabolism in neonatal screening. Because available data for premature infants is limited, we studied longitudinal changes in acylcarnitine profiles of full-term and preterm neonates over the first 4 weeks of life. One hundred twenty infants were divided into four groups of 30: A, gestational age 22 to 27 wk; B, 28 to 31 wk; C, 32 to 36 wk; and D, 37 to 41 wk. Blood samples spotted on a Guthrie card were taken on days 5 and 28. Additional specimens (groups A and B only) were collected on days 1, 3, 7, and 14. Carnitine and its acyl esters were detected by looking for the precursor ions of m/z = 85 using a PE Sciex API 365 electrospray ionization tandem mass spectrometer. Concentrations of free carnitine and most acylcarnitines were significantly higher in group A compared with group D postnatally. Groups B and C displayed intermediate values. Carnitine levels in infants from group A and B decreased steadily from day 1 to day 7, and recovered up to day 14 in group B only. On day 28 carnitine concentrations had further decreased in group A, while reaching postnatal levels again in group B. Postnatal carnitine levels are higher in very immature preterm infants compared with full-term infants, but become lower on day 28. However, the commonly used metabolite ratios should still allow the detection of inborn errors of metabolism.     

Substrate utilization during the first weeks of life

It is assumed that substrate utilization changes markedly around birth, from mainly glucose utilization before, to glucose/fat utilization after birth. We studied substrate oxidation and turnover in preterm infants on the first day and during the first weeks of life. We found that only part of the glucose that is infused on the first day of life is oxidized, while glucose is also converted into fat at the same time. Almost half of the energy expenditure is provided by fat oxidation on day 7 and 28 of life. Fat oxidation is dependent on the type of fat oxidized; the rate of oxidation of medium chain triglycerides (MCT) is higher than that of long chain fatty acids. MCT can replace glucose as an energy source. Proteins contribute only to a small extent (approximately 7%) to the energy expenditure at all ages.     

Variations in serum ferritin and erythrocyte index in the first eight weeks of life in term newborn infants

The cannabinoid system has been recently described, including the endogenous ligands, mainly arachidonic acid derivatives, and their specific receptors. Endocannabinoids are involved in the modulation of synaptic transmission, through which they exert their psychoactive, motor and antinociceptive effects, among others; they also exert extraneural effects, mainly immunomodulation and vasodilation. Recent data suggest that the cannabinoid system might play an important role in human ontogeny and could participate in the implantation and early development of the embryo, in fetal brain development, and in the beginning of breast feeding after birth. In addition, the vasodilatory effect of cannabinoids, together with inhibition of the release of excitotoxic amino acids and cytokines, as well as modulation of oxidative stress and the toxic production of nitric oxide, justify the growing evidence pointing to a possible neuroprotective effect of cannabinoids in perinatal asphyxia.     

Serum apolipoproteins and lipoprotein (a) during the first week of life

The levels of apolipoproteins, A-I, A-II, B and E, lipoprotein (a) and of total cholesterol and triglycerides were determined in cord serum and in capillary serum at the fifth day of life in a group of 44 term newborns. Additionally, cord serum lipoproteins were estimated. Sera from 26 healthy adults were studied for comparison. The concentrations of lipids and lipoproteins in cord serum were diminished as compared to adult levels. The occurrence of lipoprotein (a) in cord serum in concentrations significantly lower than in adults could be established. Serum apolipoproteins A-I, A-II and B were significantly lower at birth than in the adult, whereas apolipoprotein E levels did not differ from adult concentrations. During the first five days apolipoprotein B levels more than doubled, apolipoprotein A-I increased moderately and apolipoprotein E rose slightly. In contrast, serum lipoprotein (a) and apolipoprotein A-II did not change significantly. Unlike serum cholesterol, the levels of apolipoproteins B and E at day five were significantly correlated to those measured at birth in the same infants. The changes of the apolipoprotein pattern during the first week of life reflect the evolution of the lipid transport system of the newborn and may be related to the increasing utilisation of fat and to hormonal factors.     

Glomerular filtration rate in the first three weeks of life.

Clearances of inulin and para-aminohippuric acid were performed in 22 newborn infants without renal disease. Ages varied from 12 hours to 25 days. The mean values of inulin and PAH clearances during the first four days of life were 10.8 +/- 1.0 ml/min/m2 and 30.8 +/- ml/min/m2, respectively. A twofold increase in glomerular filtration rate was observed during the first 14 days of life. A similar increase in PAH clearance occurred during this period. No correlation was found between gestational age (range: 32 to 39 weeks) and GFR in ten neonates studied during the first four days after birth.     

Weight change in the term baby in the first 2 weeks of life

BACKGROUND: Midwives once used serial weighing to highlight lactation problems, but this is now discouraged for the fear of undermining maternal confidence. AIM: To explore weight changes in healthy newborn term babies, to gain information to aid interpretation of such measurements and to construct a centile chart for those exclusively breastfed during the first 2 weeks. METHOD: Two hundred ninety-nine mothers weighed their baby daily using the same electronic scales. In 46 cases, three or more consecutive measurements were omitted leaving 253 series to evaluate, of which 111 were exclusively breastfed. RESULTS: Breastfed babies lost a mean 6.4% of birthweight (95% CI: 5.5-7.3%) before starting to gain, and 54% took more than 8 days to regain birthweight. Artificially fed babies lost less (3.7%, 95% CI: 2.7-4.7%), but 39% had not regained their birthweight by 8 days. Once birthweight was regained, average gain was about 1% of birthweight per day in both breast- and artificially-fed babies. Measurements less than 5 days apart predicted average weight gain poorly. CONCLUSIONS: Feeding problems should be considered if weight is not increasing by 6 days, but some healthy babies take 17 days to regain their birthweight.     

Congenital hypothyroidism: decreased growth velocity in the first weeks of life

The growth velocity of 46 infants with congenital hypothyroidism, classified into three groups: athyreosis (n = 12), ectopic (n = 25) and eutopic gland (n = 9), was analyzed. Height, expressed as the standard deviation score (SDS), was measured at birth, at diagnosis and 2, 4, and 8 weeks after initiation of therapy. Bone age was retarded at birth and at diagnosis, epiphyseal surfaces of the knee were correlated with serum T4 values. By contrast, height (mean +/- SD) at birth was normal (0.3 +/- 0.8 SDS) with identical distribution among the three subgroups. Growth velocity was decreased during the first weeks of life: height at diagnosis was -0.1 +/- 0.6 SDS, a value significantly different from size at birth (p less than 0.02). After therapy was started, a continuous decline in growth velocity was observed, reaching -0.2 +/- 0.7 and -0.2 +/- 0.6 SDS, respectively, at 2 and 4 weeks of therapy (p less than 0.01 vs. size at birth). Growth retardation was correlated with the degree of thyroid deficiency. Mean height after 2 weeks of therapy was at -0.6, -0.1, 0.1 SDS in patients with athyreosis, ectopic and eutopic gland, respectively. Catch-up growth occurred thereafter, and the mean height reached 0.3 SDS at 12 weeks for the entire group. A correlation between the decrease in growth velocity and T4 levels at diagnosis was found (p less than 0.05). The normal size at birth and the decreased growth rate observed at diagnosis seem to indicate that growth becomes thyroid hormone dependent immediately after birth.     

Changes of serum allopregnanolone levels in the first 2 years of life and during pubertal development.

Allopregnanolone is the best characterized among neurosteroids, and its role in the control of neuroendocrine axes has attracted increasing interest recently. However, there is no available information about circulating levels of allopregnanolone during infancy, childhood and puberty. We studied two groups of children: 1) those aged between 0 and 2 y (n = 72), and 2) those aged between 6 and 18 y, at different Tanner's stages (n = 82). In each of these patients, serum allopregnanolone, progesterone, cortisol, and dehydroepiandrosterone levels were evaluated after informed consent; allopregnanolone was measured by RIA after acid extraction on cartridge. There was no significant variation of serum allopregnanolone levels either in male and female children during the first 2 y of life. Furthermore, although serum dehydroepiandrosterone levels showed a significant decrease, inversely correlated with age of the children (p < 0.01), serum cortisol and progesterone levels showed a significant age-related increase during the first 2 y of life. Cortisol and allopregnanolone levels were positively correlated (p < 0.01). During puberty, we observed a progressive increase in serum allopregnanolone levels in both boys and in girls, which were higher at Tanner' s stage IV-V (0.7+/-0.01 nM; mean +/- SEM) than at stages I-II (0.32+/-0.02 nM; p < 0.01); mean levels were significantly higher at puberty than in the first 2 y of life (p < 0.01). Furthermore, during puberty, serum progesterone and dehydroepiandrosterone levels also increased progressively with age in both boys and girls. Allopregnanolone and dehydroepiandrosterone levels were positively correlated throughout puberty. The present results indicate that serum allopregnanolone levels do not change during the first 2 y of life but increase during pubertal development, suggesting that this steroid may be involved in the adaptive neuroendocrine mechanisms related to puberty.     

Development of urea-synthesizing capacity in preterm infants during the first weeks of life

The urea-synthesizing capacity of the liver was studied in 20 healthy preterm infants during the first month of life. The urea-synthesizing capacity was estimated by the ratio of 15N abundances of ammonia and urea in the 6-hour urine after administration of 3 mg 15N-labelled ammonium chloride/kg body weight. The ratio increases with increasing protein intakes from the 2nd to the 3rd week of life. On protein intakes of more than 3 g/kg/protein day from the 3rd week to the end of the 2nd month of life, the ratio decreases suggesting a maturation of the urea cycle during the first weeks of life.     

Fatty acid composition in breast milk and serum phospholipids of healthy term Chinese infants during first 6 weeks of life

AIM: To compare the fatty acid (FA) pattern in early and mature breast milk with that in plasma phospholipids of cord blood and breast-fed infants. METHODS: Forty-five mother-infant pairs from western Shanghai were studied. All infants, born at term with normal weight and length, were examined at birth and days 5 and 42. FA was analyzed by capillary gas-liquid chromatography. RESULTS: Cord blood showed higher concentration of long-chain polyunsaturated FA (LCPUFA) but lower saturated (SFA) and monounsaturated (MUFA) FA than postnatal infants' plasma. SFA decreased with age in the infants, but MUFA and linoleic acid (LA, 18:2omega6) increased. LCPUFA were lower in the plasma of 5-day-old infants than in cord blood, but LA was 80%, alpha-linolenic acid (ALA, 18:3omega3) 33% and the ratio omega-6/omega-3 42% higher. At day 42, LA increased further, LCPUFA remained similar, and was in breast milk lower than at day 5, while ALA and gamma-linolenic acid (18:3omega6) were higher. The activity index of desaturases indicated high Delta9 activity in breast milk and high activity of Delta5 desaturase in the infants. CONCLUSION: Breast milk FA composition changed markedly from day 5 to 42 with increasing correlation to infants' plasma. Calculation of desaturase activities suggested high capacity of LCPUFA synthesis.     

Changes in body composition and serum lipid fractions after four weeks of slimming treatment: results in nineteen obese male adolescents

The changes in body composition and in serum levels of total cholesterol (T-chol), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), very low plus low density lipoprotein cholesterol (VLDL + LDL-C), the ratio T-chol/HDL-C and non esterified fatty acid (NEFA) were studied in nineteen obese male adolescents after 28 days of slimming treatment which consisted in hypoenergetic diet and exercise. Relative fat body weight (%BF) was calculated by Parizková and Roth's regression equations for five fatfolds and lean body weight was obtained as the difference between body weight and fat body weight. Significant reductions in %BF, T-chol and T-chol/HDL-C ratio were found. The decrease in TG was not significant but had a better correlation with the reduction of adiposity (delta %BF) than the previously mentioned two variables. The increase of lipolysis during the four weeks of study is expressed in the significant rise of NEFA and its correlation (r = -0.714) with delta %BF. A tendency to increase in HDL-C could be observed, and a significant inverse correlation (r = -.804) with delta %BF was found. The results obtained showed that the combination of diet and exercise for treating obesity in adolescents influences favourably the risk factors of ischaemic heart disease related to serum lipid and lipoprotein profiles and does not significantly affect lean body mass, at least up to four weeks.     

Antibody neutralizing material of factor VII during the first weeks of life

In a study on 66 newborns and infants, factor VII activity and factor VII related antigen were investigated on 110 occasions. A normal range was calculated by testing plasma from 12 healthy male volunteers at various dilutions. Most of the values in the newborns and infants fell within this range but 18.2% of the factor VII proteins showed a significantly different specific activity.In honour of Prof. Dr. Goetze (Director of the Institute of Pathophysiology of the University Jena) on the occasion of his 65th birthday