Transdermal suctioning technique for serial sampling of interstitial fluid in newborn infants.

OVERVIEW: Use of a suction-induced epidermal mini-erosion for serial sampling of dermal interstitial fluid (IF) in 16 newborn infants with gestational age ranging from 24 to 42 weeks is reported. RESULTS: The mini-erosion formed reproducibly and electron microscopy showed that the split was located within the epidermis. IF was sampled serially by suctioning during 1-3 days without signs of stress or pain. IF sample volumes (10-50 microl) did not decrease with time. Glucose values in IF and blood were correlated (r(s) = 0.542; p = 0.000). IF glucose was lower than blood glucose on all 3 days. The epidermis regenerated within 4 +/- 0.9 days (mean, SD) after sampling was terminated. There were no complications. CONCLUSION: Serial transdermal sampling was performed without stress or pain in newborn infants. Systemic and temporal differences between glucose measured in IF and blood were observed.

Tolerance to early human milk feeding is not compromised by indomethacin in preterm infants with persistent ductus arteriosus.

AIM: Early human milk feeding is beneficial for gut and brain development. Persistent ductus arteriosus (PDA) and indomethacin may compromise enteral function in preterm infants. For many years enteral milk feedings have continued in preterm infants receiving indomethacin for PDA. The aim of this study was to investigate whether this strategy is efficient in terms of risks and tolerance to early enteral feeding. METHODS: This retrospective study included 64 inborn infants of <29 wk gestational age (GA), 32 infants who received indomethacin for symptomatic PDA (case infants) and 32 matched controls. Case infants had a mean (SD) GA of 26.3 wk (1.3) and body weight 839 g (203) versus controls GA 26.4 wk (1.2) and body weight 896 g (213) (p = 0.82 and 0.27, respectively). Case infants had higher respiratory morbidity; 90.6% versus 50% of controls needed mechanical ventilation (p = 0.000). RESULTS: Case infants received human milk from a median (range) age of 4.0 h (1.5-27.5), and controls from 5.3 h (2.0-38.0) (p = 0.092). The first dose of indomethacin was given at a mean age of 1.7 d (1.0). There were no differences between the two groups in feeding volumes or gastric residuals on days 1 to 7. Mean (SD) feeding volume on day 7 was 64 ml/kg (31) in case infants and 76 ml/kg (30) in controls (p = 0.23). Four infants developed necrotizing enterocolitis: two case infants and two controls (p = 1.00). CONCLUSION: Early enteral feeding with human milk, starting within the first hours of life, seems to be as well tolerated in preterm infants treated with indomethacin for PDA as in their matched controls.

Plasma neutrophil lipocalin, elastase-alpha1-antitrypsin complex and neutrophil protease 4 in preterm infants with respiratory distress syndrome.

Respiratory distress syndrome (RDS) and chronic lung disease of prematurity (CLD) are associated with inflammation of the airways and interstitial tissue of the lung. It is hypothesized that RDS severity and the risk of developing CLD may be correlated with neutrophil gelatinase-associated lipocalin (NGAL), a marker of leucocyte activity, human elastase-alpha1-antitrypsin complex (HEAT) or free and complexed neutrophil protease 4 (NP4), markers of proteolytic enzyme secretion from granulocytes. Thirty-three preterm infants with RDS were enrolled in the study and plasma sampled between 3 and 14 days of life. NGAL, HEAT and NP4 concentrations varied widely in infants with RDS. Significant correlations between subsequent development of CLD and plasma concentrations of HEAT and NP4, respectively, were found on days 3-4 of life, p=0.006 and p=0.02, respectively.

Tracheobronchial aspirate fluid neutrophil lipocalin, elastase- and neutrophil protease-4-alpha1-antitrypsin complexes, protease inhibitors and free proteolytic activity in respiratory distress syndrome.

UNLABELLED: This study aimed to determine whether the protease/protease inhibitor balance and neutrophil activity is of pathophysiological importance in the severity and resolution of respiratory distress syndrome (RDS) and the eventual development of neonatal chronic lung disease (CLD). Ventilated preterm infants with RDS (n = 43) were studied during their first week of life. Tracheobronchial aspirate fluid (TAF) concentrations of neutrophil lipocalin, the elastase- and neutrophil protease-4 (NP4) complex concentrations, and alpha1-antitrypsin (alpha1AT), antichymotrypsin (ACT) and secretory leucocyte protease inhibitor (SLPI) levels were analysed. Free proteolytic and elastolytic activities were also determined. CLD correlated with low alpha1AT (p = 0.02) and ACT (p = 0.02) levels at 3-4 d of age and low SLPI (p = 0.03) at 7-8 d of age. No correlations were found between CLD or severity of RDS (as judged from radiological examination) and neutrophil lipocalin, elastase- and NP4-alpha1AT complexes during the first week of life, with one exception: RDS X-ray severity and the elastase-alpha1AT complex concentration were correlated at 3-4d of age (p = 0.02). Free proteolytic activity occurred in the TAF of 7/30 infants tested on day 3-4 and free elastolytic activity in 1 patient. During the rest of the first week of life no free elastolytic or proteolytic activities were observed. Caesarean section was correlated with low levels of SLPI on day 3-4 (p = 0.01), NP4 (p = 0.03) and ACT (p = 0.05) on day 5-6. Gestational age was positively correlated with protease inhibitors and their complexes at 3-4 d of age. CONCLUSION: Free proteolytic or elastolytic activity in the TAF of RDS infants in the first week of life occurred by way of exception. Elastase-/NP4-alpha1AT complex or neutrophil lipocalin levels were not correlated with the development of CLD. The correlation between CLD and low alpha1AT or ACT at 3-4 d and SLPI at 7-8 d of age may be due to either immaturity or complex formation. The severity of RDS as judged from radiological examination was correlated with elastase-alpha1AT complex on day 3-4. The main hypothesis, that TAF protease/protease inhibitor levels or imbalance and leucocyte activity are important factors indicating a high risk of severe RDS and subsequent CLD development, was principally not confirmed.

Individualized protein fortification of human milk for preterm infants: comparison of ultrafiltrated human milk protein and a bovine whey fortifier.

BACKGROUND: To improve the nutritional management of pre-term infants, a new individualized human milk fortification system based on presupplementation milk protein analyses was evaluated. METHODS: In an open, prospective, randomized multicenter study, 32 healthy preterm infants (birth weights, 920-1750 g) were enrolled at a mean of 21 days of age (range, 9-36 days) when tolerating exclusive enteral feedings of 150 ml/kg per day. All infants were fed human milk and were randomly allocated to fortification with a bovine whey protein fortifier (n = 16) or ultrafiltrated human milk protein (n = 16). All human milk was analyzed for protein content before fortification with the goal of a daily protein intake of 3.5 g/kg. During the study period (mean, 24 days) daily aliquots of the fortified milk were obtained for subsequent analyses of the protein content. RESULTS: Both fortifiers were well tolerated, and growth gain in weight, length, and head circumference, as well as final preprandial concentrations of serum urea, transthyretin, transferrin, and albumin were similar in both groups. The ultimate estimated protein intake was equivalent in both groups (mean 3.1+/-0.1 g/kg per day). Serum amino acid profiles were similar in both feeding groups, except for threonine (significantly higher in the bovine fortifier group) and proline and ornithine (significantly higher in the human milk protein group). CONCLUSIONS: Protein analyses of the milk before individual fortification provides a new tool for an individualized feeding system of the preterm infant. The bovine whey protein fortifier attained biochemical and growth results similar to those found in infants fed human milk protein exclusively with the corresponding protein intakes.

Effect of infant formula zinc and iron level on zinc absorption, zinc status, and immune function in infant rhesus monkeys.

To evaluate the effects of marginal zinc (Zn) deficiency on Zn absorption and metabolism, three groups of infant rhesus monkeys (n = 4/group) were fed from birth to 5 months of age either a regular infant formula (5 mg Zn/L) or a low-Zn formula (1 mg Zn/L). Since iron (Fe) intake may affect Zn absorption, the low-Zn formula was given without (1 mg Fe/L) or with Fe fortification (12 mg/L). At monthly intervals, Zn absorption and retention were assessed by gavage feeding with 65Zn and whole-body counting immediately after and on days 4, 7, and 11 after intubation. Blood samples were drawn before dosing for analyses of various potential markers of Zn status. Infants fed low-Zn formula had lower weight gain than controls; however, length growth was similar in all groups. 65Zn retention was considerably higher in both groups fed low-Zn formula (40%) than in the control group (20%), whereas plasma Zn levels were normal in all infants. Plasma metallothionein levels were generally very low and detectable in only 5 samples of 48; however, 4 of these were found in control infants. Neutrophil chemotaxis assessed at the end of the study was impaired in low-Zn infants compared to controls. In addition, low-Zn infants had increased levels of interleukin-2 at the end of the study. No differences were seen between the groups in hemoglobin levels, total white blood cells/absolute neutrophil counts, or plasma activities of 5'-nucleotidase or angiotensin converting enzyme. In conclusion, marginal Zn intake in infant rhesus monkeys resulted in increased Zn retention, which was not enough to completely compensate for the lower Zn intake. The higher level of iron fortification studied did not affect Zn retention significantly.

Simple and rapid macronutrient analysis of human milk for individualized fortification: basis for improved nutritional management of very-low-birth-weight infants?

Feeding human milk exclusively to the very-low-birth-weight infant may lead to insufficient intakes of protein and energy. Although the milk is therefore often supplemented with protein and additional calories, there is usually no prior information on its macronutrient composition. If such data were available, it would be possible to individualize the fortification of the milk. To find simple, rapid, and inexpensive methods of enriching it, we evaluated existing macronutrient assays of human milk. Thirty frozen samples of early human milk (3-20 days of lactation) were analyzed for contents of protein (Kjeldahl, Lowry, and Bio-Rad protein assays), fat (Folch, total lipids assay, and creamatocrit), and carbohydrates (lactose and orcinol assays). The methods were modified to minimize cost and time. From these data, we find it appropriate to recommend the use of the Lowry (or, alternatively, the Bio-Rad) protein assay, the total lipids assay, and the orcinol carbohydrate assay for reasonably accurate determinations of the protein and energy contents of human milk. Because the variation in the carbohydrate content of human milk is very small, a more simple alternative approach would be to include only an average carbohydrate value for an estimate of energy content. These low-cost methods can be used in all laboratories affiliated to neonatal units taking care of preterm infants. Such individualized fortification should serve to further improve the nutritional management of very-low-birth-weight infants.

Alterations in intestinal uptake and compartmentalization of zinc in response to short-term dexamethasone therapy or excess dietary zinc in piglets.

Premature infants receive high dietary zinc and often glucocorticoids as a treatment for chronic lung disease. A piglet model was developed to investigate intestinal zinc transport and distribution of tissue zinc in response to treatment with short-term (5 d) glucocorticoid therapy or a high zinc diet. Piglets (13-15 d old; n = 21) were randomly allocated to: 1) dexamethasone (DEX) therapy (1.5 mg/kg intramuscularly twice a day), 2) high zinc diet (15.3 mmol/kg), or 3) control group (0.3 mmol dietary zinc/kg and saline intramuscularly twice a day). Pig weight, formula intake, urine volume, and blood glucose were monitored. At necropsy, tissue samples were obtained to measure zinc in plasma and zinc and metallothionein in liver and small intestinal mucosa. Velocity of zinc uptake by intestinal brush border membrane vesicles was measured using 65Zn tracer. Maximum uptake rate and Km for zinc uptake by brush border membrane vesicles were significantly greater (p < 0.05) in DEX compared with control and high zinc groups. DEX-treated piglets had a significantly lower (p < 0.05) zinc efflux rate across brush border membrane vesicles compared with that of the control. The high zinc group had a higher liver (p < 0.05) and mucosal (p < 0.05) zinc content and higher liver metallothionein concentration (p < 0.001) compared with the control and DEX groups. Weight gain over 5 d was not different among groups. Daily blood glucose was higher (p < 0.05) in DEX versus control and high zinc groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical evaluation of the fetus and neonate. Relation between intra-partum cardiotocography, Apgar score, cord blood acid-base status and neonatal morbidity.

The relation between intra-partum cardiotocography (CTG), cord blood acid-base status, Apgar score and neonatal morbidity was studied in 1228 consecutively live-born babies and in a subgroup of 200 babies (148 babies with a 1 min Apgar score < or = 8 and 52 randomly selected babies with a 1 min Apgar score > or = 9). The scores for the individual components of the 1 min Apgar score were strongly associated with each other, whereas the scores for the individual components of the 5 min Apgar score were less strongly associated. At 1 min the scores for muscle tone, reflex irritability and respiration but not the scores for heart rate and skin colour were associated with arterial and venous cord blood pH (low scores being associated with low pH). Out of the individual components of the Apgar score, heart rate and reflex irritability at 1 min were the best discriminators between "healthy or relatively healthy" and "severely ill" babies. Intrapartum CTG, total Apgar score and cord blood acid-base status were only weakly related. Venous cord blood pH was the best predictor of the 1 min Apgar score. Intra-partum CTG (silent pattern), 5 min Apgar score and venous cord blood pH were the best predictors of severe neonatal morbidity.

Amino acid concentrations in plasma and urine in very low birth weight infants fed protein-unenriched or human milk protein-enriched human milk.

Preprandial plasma and urine amino acid concentrations were measured in 28 growing, very low birth weight, appropriate-for-gestational-age infants randomly assigned to either protein-unenriched (n = 14) or human milk protein-enriched (n = 14) human milk. The two groups of infants had similar birth weights (900 to 1500 g) and gestational ages (26 to 32 weeks). The study was initiated at a mean age of 19 days when the infants tolerated full feeding volumes and lasted for a mean time of 28 days. Mean protein intake values were 2.1 +/- 0.3 and 3.6 +/- 0.3 g/kg per day (mean +/- SD) and weight gain values were 26.6 +/- 7.4 and 35.1 +/- 3.6 g/day in the protein-unenriched and the protein-enriched groups of infants, respectively. Human milk protein enrichment resulted in significantly increased concentrations of all plasma amino acids except serine, taurine, and histidine. Most urine amino acid concentrations correlated with protein intake and with the plasma concentrations, suggesting that the effects of protein quality and quantity can be evaluated by measuring urinary amino acid concentrations alone, thereby making such studies less invasive. Infants fed protein-unenriched human milk had growth rates below the estimated intrauterine rate as well as low plasma and urine amino acid concentrations, indicating suboptimal protein intake levels. When the plasma concentrations of the essential amino acids in the protein-enriched infants from the present study were compared with concentrations found in the literature in fetal and umbilical cord plasma, both were found to be much higher.(ABSTRACT TRUNCATED AT 250 WORDS)

Eleven plasma proteins as indicators of protein nutritional status in very low birth weight infants.

Concentrations of 11 plasma proteins were measured in 28 healthy, growing, very low birth weight, appropriate-for-gestational-age infants fed varying levels of human milk protein intake (range 1.7 to 3.9 g/kg per day). Significant positive correlations were found between mean protein intake and concentrations of 7 of the plasma proteins studied (transthyretin, retinol-binding protein, and transferrin: P less than .001; vitamin D-binding protein and apolipoprotein B: P less than .01; albumin and apolipoprotein A I: P less than .05). A weak negative correlation with mean protein intake was seen for the plasma level of orosomucoid, whereas no significant correlations were found for the plasma concentrations of fibronectin and alpha 1-antichymotrypsin. Protein intake, not energy intake, constituted the main contribution to the changes in the concentrations of transthyretin, retinol-binding protein, and transferrin. The levels of plasma transthyretin and transferrin were also strongly correlated with weight and length growth of the infants during the study as well as with other indicators of protein nutritional status such as preprandial concentrations of plasma amino acids and serum and urine urea. These data indicate that of the 11 plasma proteins studied, transthyretin, transferrin, and retinol-binding protein are the most suitable to evaluate protein nutritional status in very low birth weight infants.

Concentration of twelve plasma proteins at birth in very low birthweight and in term infants.

Plasma samples obtained at birth from 70 very low birth weight (VLBW) infants (gestational age 24 to 34 weeks) and from 20 term infants were analysed for concentrations of 12 different proteins. The plasma concentrations of albumin, transthyretin (TTR), retinol-binding protein (RBP), vitamin D-binding protein, apolipoprotein A I, fibronectin, orosomucoid and alpha 1-antichymotrypsin were significantly lower in the VLBW infants than in the term infants, whereas the values of alpha-fetoprotein (AFP) were significantly higher in the VLBW infants. No differences were found between the two groups for apolipoprotein A II, apolipoprotein B and transferrin. Birth asphyxia and sex had no influence on the measured plasma protein concentrations. The plasma concentrations of apolipoprotein A I and A II were significantly lower in small-for-gestational age (SGA), VLBW infants compared with appropriate-for-gestational age (AGA), VLBW infants. Possible acute inflammation (defined as raised concentrations of orosomucoid or alpha 1-antichymotrypsin) was associated with significantly higher values of vitamin D-binding protein in both VLBW and term infants, suggesting that this protein may act as an acute phase protein in newborn infants.

Urinary and serum urea as indicators of protein metabolism in very low birthweight infants fed varying human milk protein intakes.

Urea concentrations in serum and urine were measured in 28 growing, very low birth weight, appropriate-for-gestational age infants fed varying human milk protein intakes (range 1.7 to 3.9 g/kg/day). We found a high correlation between serum urea values at the end of the study and mean protein intake (rs = 0.85, p less than 0.001) and between urinary urea concentrations in eight-hour urine collections and protein intake (rs = 0.81, p less than 0.001). All serum and urine urea values were below 1.6 and 18 mmol/l, respectively, at protein intakes less than 3 g/kg/day. Higher protein intakes caused higher serum and urinary urea concentrations. We also found a strong correlation between the individual serum and urinary urea values at the end of the study (rs = 0.90, p less than 0.001). The presented data are consistent with the growth data previously reported and indicate that inadequate or excessive protein intakes can be detected by measurement of urea concentrations in serum and/or urine. If urine urea samples alone can be used for estimating optimal protein intake, painful blood sampling procedures could be obviated.

Macromolecular absorption in preterm and term infants.

Human alpha-lactalbumin (alpha-LA) has been used as a marker for measuring macromolecular absorption. The serum concentration of human alpha-LA after a human milk feed has been studied in 32 healthy very low birthweight infants (VLBW), fed human milk (gestational age 26-32 weeks) and in 56 term, breast-fed infants, age 3-140 days. At 31 weeks of gestation the serum concentration of human alpha-LA was more than 10 times higher (mean value 3,000 and median value 2,101 micrograms/l serum/l human milk/kg body weight, n = 11) than in the term infants aged 3-30 days (mean value 257 and median value 152, n = 29). The serum concentration of alpha-LA decreased with increasing maturity in the VLBW-infants. At a postconceptional age of 37 weeks the values were similar (mean value 200 and median value 99, n = 8) to those found for term infants during the first month. In the term infants a decreasing absorption of alpha-LA was found with increasing postnatal age.

Growth of very low birth weight infants on varying amounts of human milk protein.

In a double-blind, randomized study, 28 healthy, growing very low birth wt, appropriate-for-gestational-age infants were fed human milk, preferably mother's own, fortified daily with human milk protein and/or human milk fat. The infants entered the study when they were stable on complete enteral intakes of 170 mL/kg/d (mean age = 19 d). The study lasted for a mean of 4 wk. Samples from all the milks were collected daily, and intakes of protein, fat, carbohydrates, energy, and electrolytes were calculated weekly during the whole study period. Protein intakes ranged from 1.7 to 3.9 g/kg/d, and energy intakes from 100 to 150 kcal/kg/d. Wt and length gain in the nonprotein-enriched groups were 15.6 +/- 2.7 g/kg/d (mean +/- SD) and 0.88 +/- 0.17 cm/wk; the corresponding figures for the protein-enriched groups were 20.2 +/- 2.1 g/kg/d and 1.24 +/- 0.14 cm/wk. There was a strong correlation between protein intake and growth in wt and length up to an intake of about 3 g/kg/d; more protein did not result in increased growth. The same was true for energy intake, with a maximal growth rate at an intake of about 120 kcal/kg/d. A protein intake of more than 3 g/kg/d resulted in a growth rate equal to or higher than the estimated intrauterine growth rate. Some infants fed mature banked human milk alone had a poor growth. Sodium intake was low, ranging from 1.5 to 2.6 mmol/kg/d. No correlation was found between sodium intake and growth rates.

Early-onset neonatal group B streptococcal septicaemia in siblings.

At each of two consecutive deliveries, a woman gave birth to a baby that developed early-onset group B streptococcal (GBS) septicaemia. A low titre of serum antibodies to the type of the infecting GBS and persistence of the organism in the mother were demonstrated. This case confirms that mothers of GBS infected infants are at high risk of their future babies being similarly infected.

Perinatal outcome in growth retarded pregnancies dated by ultrasound.

To analyse the incidence of fetal growth retardation and its impact on perinatal mortality and neonatal morbidity, pregnancies complicated by intra-uterine growth retardation (IUGR) were compared with matched non-IUGR pregnancies. The IUGR group included all infants born in the city of Malmö during the study period and having a birthweight of 2 standard deviations or more below the mean birthweight for gestational age. The gestational age of all pregnancies was assessed with ultrasound in the first half of pregnancy. The IUGR fetuses were more vulnerable during delivery, and emergency cesarean section due to imminent fetal asphyxia was performed more frequently, but Apgar scores were similar in both groups. The frequency of respiratory disorders was lower in the IUGR group than in the non-IUGR group when corticosteroid-treated pregnancies were excluded. The IUGR group required slightly longer care on the neonatal ward than the non-IUGR group, but not more intervention. The IUGR group as a whole had an unexpectedly low neonatal complication rate, such complications as did occur being related to preterm birth rather than to growth retardation.