The incidence of and risk factors for hyperglycemia and hypoglycemia in preterm infants receiving early-aggressive parenteral nutrition

Introduction

Optimizing nutritional support helps prevent extra uterine growth restriction and adverse long-term outcomes in preterm infants.

Objectives

This study aimed to analyze the incidence of and risk factors for hyperglycemia and hypoglycemia in preterm infants receiving early-aggressive parenteral nutrition (PN).

Methods

This prospective observational study included preterm infants receiving PN at the Neonatal Intensive Care Unit of Dr. Soetomo General Hospital between April 2018 and May 2019. Potential risk factors analyzed included asphyxia, sepsis, respiratory distress syndrome, multiple congenital anomalies, mortality, necrotizing enterocolitis, retinopathy of prematurity, the postoperative period, inotropic administration, glucose infusion rate (GIR) > 10-12 mg/kg/min, GIR 4-<5.5 mg/kg/min, and increase in GIR <1 mg/kg/min.

Results

Of the 105 preterm infants included, hyperglycemia and hypoglycemia were found in 14 (13.3%) and 26 (24.8%) infants, respectively, with most incidents occurring in the first week (hyperglycemia: 85.7%; hypoglycemia: 88.5%). Sepsis was an independent risk factor for hyperglycemia (odds ratio [OR]: 8.743, 95% confidence interval [CI]: 2.392-31.959; P = 0.001). Hypoglycemia independent risk factors included the postoperative period (OR: 4.425, 95% CI: 1.218-16.073; P = 0.024) and use of GIR 4-<5.5 mg/kg/min (OR: 2.950, 95% CI: 1.035-8.405; P = 0.043).

Conclusion

Hyperglycemia and hypoglycemia can occur in preterm infants receiving early-aggressive PN; most cases occur within the first week of life. Hypoglycemia correlated with low glucose intake, and hyperglycemia correlated with sepsis. Monitoring blood glucose levels in preterm infants receiving PN, especially in the first weeks of life, may decrease morbidity associated with hyperglycemia or hypoglycemia.

Levels of 25 cytokines in the first seven days of life in newborn infants

BACKGROUND

Novel methods for cytokine analysis allow for the simultaneous measurement of 25 cytokines in 50 μL serum or plasma. Data on values of most of these cytokines in non-infected newborn infants are lacking. We analyzed levels of 25 cytokines in the first week of life in non-infected preterm and term infants and related them to gestational age.

FINDINGS

During the first week after birth, no trend over time was found in any of the cytokines, except for IL-1Ra and IL-6 where higher values were found in the first four hours. Between 24 and 72 hrs levels of IL-1Ra, IL-2, IL-8, IL-12, IL-13, IL-15, IL-17, IFNγ, MIP-1a, MCP-1, TNFα were lower in infants born after 30-32 wks compared to infants ≥ 36 wks; levels of IL-6, IL-10, IP-10 were lower in preterm infants of both 30-32 and 33-36 weeks. No difference between groups for any of the levels was found for IL-1b, IL-2r, IL-4, IL-5, IL-7, IFNa, MIP-1b, GM-CSF, Eotaxin and RANTES.

CONCLUSIONS

Levels of 25 interleukines are stable in the first week of life in non-infected infants. Infants born after 30-32 wks showed lower levels of fourteen cytokines compared to infants born after more then 36 wks. This indicates a lower stimulation or activation of Th-1 cells, monocytes and dendritic cells in these infants.

Analgesics, sedatives and neuromuscular blockers as part of end-of-life decisions in Dutch NICUs

BACKGROUND

Clinicians frequently administer analgesics and sedatives at the time of withholding or withdrawal of life-sustaining treatment in newborns. This practice might be regarded as intentionally hastening of death.

OBJECTIVE

To describe type, doses and reasons for administering medications as part of end-of-life decisions in the Dutch neonatal intensive care units.

DESIGN AND SETTING

We reviewed the medical files of 340 newborn deaths with a preceding end-of-life decision over a 12-month period to describe the use of analgesics, sedatives and/or neuromuscular blockers. The neonatologists of 147 of the 150 newborns with a preceding end-of-life decision based on the infant's poor prognosis were interviewed to obtain additional details about the use of medication.

RESULTS

Analgesics and sedatives were administered to 224 of 340 newborns before the end-of-life decision and to 292 newborns after the decision. The medication was increased in 94 of 289 newborns whose death was imminent and in 110 of 150 newborns with a poor prognosis. Reasons for the increase were treatment of pain and suffering, and in 4% of cases hastening of death. Reasons were undocumented in 55% of deaths. Neuromuscular blockers were administered in 16% of patients because they already received these agents or to stop or prevent gasping.

CONCLUSIONS

Analgesics and sedatives are generally increased after the end-of-life decision to treat pain and suffering and rarely to hasten death. Neuromuscular blockers were administered in 16% of deaths. Medical files provide insufficient documentation of considerations leading to the increase of medication, which hinders (external) review.

Physician end-of-life decision-making in newborns in a less developed health care setting: insight in considerations and implementation

BACKGROUND

A substantial proportion of the decisions to withhold or withdraw life-prolonging treatment are based on the newborn's predicted poor quality of life. All previous studies on end-of-life decisions were done in countries with adequate support for disabled neonatal intensive care units (NICU) survivors. Data on quality-of-life considerations in countries with developing health care are not available yet.

AIM

The aim of the study was to examine the considerations of physicians taking end-of-life decisions in sick newborns and how those decisions are carried out in practice in a less developed health care setting.

METHOD

Thirty-two deaths over 18 months in a neonatal unit were retrospectively analyzed.

RESULTS

Twenty-four deaths (75%) were attributable to withholding or withdrawing of treatment. In 7 of these cases (29%), the decisions were based on quality-of-life considerations, mostly predicted suffering and expected hospital dependency. For the majority of paediatricians, end-of-life decision making was not influenced by legal or economic considerations or by considerations regarding availability of supportive care after discharge.

CONCLUSION

Our study suggests that physician end-of-life decision making in this unit in a less developed health care setting is found to be similar to that in developed health care settings and is independent of availability of supportive care after discharge for infants with disabilities.

[Deliberate termination of life in newborns in The Netherlands; review of all 22 reported cases between 1997 and 2004]

OBJECTIVE

To gain insight into the reporting and assessment of active termination of life in newborns in The Netherlands. DESIGN; Retrospective.

METHOD

Data on all cases of deliberate termination of life in newborns up to the age of 6 months, reported to the public prosecutor as from 1997 onward, were collected and compared.

RESULTS

In January 1997-June 2004, 22 cases of deliberate termination of life in newborns were reported. All cases concerned newborns with spina bifida and hydrocephalus. Deliberate termination of life was acceptable to the physicians because of the presence of hopeless suffering, with no means of alleviating the suffering. In all cases, at least 2 doctors were consulted outside the medical team. In 17 of 22 cases, a multidisciplinary spina bifida team was consulted. All parents consented to the termination of life; in 4 cases they explicitly requested it. In 14 cases a combination of analgesics, sedatives and paralyzing drugs were used, in 8 cases only analgesics and sedatives were administered. For the public prosecutor the termination of life was acceptable if 4 requirements were properly fulfilled: the presence of hopeless and unbearable suffering, consent of the parents to termination of life, consultation having taken place and a careful execution ofthe termination. The mean time between reporting of the case and the decision concerning prosecution was 5.3 months. None of the cases led to prosecution.

CONCLUSION

Three cases of deliberate termination of life in newborns were reported in The Netherlands annually. The public prosecutor used fixed criteria to assess the case and all cases of active termination of life reported were found to be in accordance with good practice.

[Breast feeding during the first few days after birth: sometimes insufficient]

Two newborn infants that were receiving breast-feeding were admitted to hospital for drowsiness and jaundice on the 6th and 4th day of life, respectively; these were a male infant that had been yellow since the very first day and a female infant that did not grasp the breast properly. Both recovered thanks to phototherapy and the administration of extra fluids. Seven days after discharge, the female infant was readmitted for the same symptoms, after which the breast-feeding was found to be insufficient and the infant was put on bottle-feeding. In infants that are being breast-fed, insufficient intake can result in dehydration with all of its consequences. Such insufficient intake may be difficult to recognise. Weight loss greater than 5% implies that more frequent feeding is necessary and a loss of more than 10% may mean that supplementary feeding is necessary, albeit temporarily.

Postprandial chylomicron clearance rate in late teenagers with diabetes mellitus type 1

A delayed chylomicron (CM) clearance rate, a known risk factor for atherosclerosis, has been described in adults with diabetes type 1 (DM1). We determined the CM clearance rate in late teenagers with DM1, and the relationship between CM clearance rate and elevated plasma lipid concentrations in DM1 teenagers in poor metabolic control (as characterized by HbA(1c) percentage). Plasma lipids and CM clearance were determined in nine patients with DM1 (mean age +/- SD: 17.5 +/- 0.6 y) and four healthy controls (mean age +/- SD: 20.1 +/- 0.8 y), by measuring breath (13)CO(2), plasma triglyceride, retinyl palmitate, and (13)C-labeled oleic acid concentrations, after oral administration of a fat-rich meal together with vitamin A and (13)C-oleic acid. In patients with DM1, fasting triglyceride and cholesterol concentrations were positively correlated with HbA(1c) percentage (p < 0.05). Neither in DM1 patients, nor in controls, was an elevated triglyceride concentration (above 1.7 mmol/L) found. Yet, in 22% of DM1 patients, cholesterol concentration was above 5.2 mmol/L, but not in any of the controls. CM clearance rate in DM1 patients was similar to that in controls and did not significantly correlate with HbA(1c) percentage. Fasting lipid concentrations in DM1 patients were not significantly correlated with CM clearance rate. Present data indicate that elevated lipid concentrations in late teenagers with DM1 are not attributable to a delay in CM clearance rate. A delayed CM clearance rate at late teenager age is not a risk factor contributing to the increased risk for atherosclerosis in DM1.

Estimation of gluconeogenesis in newborn infants

The rate of glucose turnover (R(a)) and gluconeogenesis (GNG) via pyruvate were quantified in seven full-term healthy babies between 24 and 48 h after birth and in twelve low-birth-weight infants on days 3 and 4 by use of [(13)C(6)]glucose and (2)H(2)O. The preterm babies were receiving parenteral alimentation of either glucose or glucose plus amino acid with or without lipids. The contribution of GNG to glucose production was measured by the appearance of (2)H on C-6 of glucose. Glucose R(a) in full-term babies was 30 +/- 1.7 (SD) micromol. kg(-1). min(-1). GNG via pyruvate contributed approximately 31% to glucose R(a). In preterm babies, the contribution of GNG to endogenous glucose R(a) was variable (range 6-60%). The highest contribution was in infants receiving low rates of exogenous glucose infusion. In an additional group of infants of normal and diabetic mothers, lactate turnover and its incorporation into glucose were measured within 4-24 h of birth by use of [(13)C(3)]lactate tracer. The rate of lactate turnover was 38 micromol. kg(-1). min(-1), and lactate C, not corrected for loss of tracer in the tricarboxylic acid cycle, contributed approximately 18% to glucose C. Lactate and glucose kinetics were similar in infants that were small for their gestational age and in normal infants or infants of diabetic mothers. These data show that gluconeogenesis is evident soon after birth in the newborn infant and that, even after a brief fast (5 h), GNG via pyruvate makes a significant contribution to glucose production in healthy full-term infants. These data may have important implications for the nutritional support of the healthy and sick newborn infant.

Measurement of parameters of cholic acid kinetics in plasma using a microscale stable isotope dilution technique: application to rodents and humans

A stable isotope dilution method is described that allows measurement of cholic acid (CA) kinetics, that is, pool size, fractional turnover rate (FTR), and synthesis rate in mice, rats, and humans. Decay of administered [2,2,4,4-2H4]CA enrichment was measured in time in 50-microl plasma samples by gas-liquid chromatography/electron capture negative chemical ionization-mass spectrometry, applying the pentafluorobenzyl-trimethylsilyl derivative. The kinetic data expressed species-dependent differences. The CA pool sizes were 16.8 +/- 2.1, 10.6 +/- 1.2, and 2.4 +/- 0.7 micromol/100 g body weight for mice, rats, and humans, respectively. The FTR values were 0.44 +/- 0.03, 0.88 +/- 0.10, and 0.46 +/- 0.14 per day for mice, rats, and humans. The corresponding synthesis rates were 7.3 +/- 1.6, 9.3 +/- 0.1, and 1.0 +/- 0.2 micromol/100 g body weight per day. The human data agreed well with literature data obtained by conventional isotope dilution techniques. For rats and mice these are the first reported isotope dilution data. The method was validated by confirmation of isotopic equilibrium between biliary CA and plasma CA in the rat. Its applicability was demonstrated by the observation of increased CA FTR and CA synthesis rate in rats fed cholestyramine, which is known to increase fecal bile acid excretion. The presented stable isotope dilution method enables the determination of CA kinetic parameters in small plasma samples. The method can be applied in unanesthetized rodents with an intact enterohepatic circulation and may also be valuable when studying the development of human neonatal bile acid kinetics.

Neurological outcome in school-age children after in utero exposure to coumarins

The effect of prenatal exposure to coumarins (acenocoumarol, phenprocoumon) on neurological outcome was assessed in a cohort of 306 children aged 7-15 years. Findings were compared with those in a non-exposed cohort of 267 children, matched for sex, age, and demographic region. We used a neurological examination technique which pays special attention to minor neurological dysfunction (MND). None of the children was found to be neurologically abnormal. However, exposure to coumarins during gestation increases the risk for MND in children of school age, odds ratio (OR) 1.9 (CI(95) 1.1-3.4), predominantly after exposure in the second or third trimester, odds ratio 2.1 (CI(95) 1.2-3.8). We found a dose-response relationship with an odds ratio of 1.2 (CI(95) 1.0-1.5) per mg coumarin derivative prescribed per day. The results suggest that coumarins have an influence on the development of the brain which can lead to mild neurological dysfunctions in children of school age.

Ethical dilemmas in neonatology: recommendations of the Ethics Working Group of the CESP (Confederation of European Specialists in Paediatrics)

Neonatal intensive care has greatly improved the survival chances of a very sick infant. At the same time, it has also given rise to serious ethical problems. In all circumstances, however, parents and paediatricians and other healthcare team workers should continuously evaluate together what is in the best interest of the infant and react accordingly. It is also clear that the principle "the best interests of the infant" can be interpreted in different ways; therefore no simple guideline is possible.

Coumarins during pregnancy: long-term effects on growth and development of school-age children

Anticoagulation during pregnancy is complicated because of potential risks for mother and foetus. Unfractionated or low-molecular-weight heparin is used for most anticoagulant indications. Its efficacy, however, in pregnant women with prosthetic heart valves is questioned, therefore coumarins are preferred for this indication. We studied long-term effects of prenatal coumarin-exposure on growth and on neurological, behavioural and cognitive development in 274 school-age children in comparison with 231 age-matched non-exposed controls. No major abnormalities were found. The exposed children had an increased risk for minor neurological dysfunction and for a low intelligence quotient (IQ below 80). The risk for a combination of two or more (minor) abnormalities was higher for the exposed children, RR = 7.6. We conclude that prenatal exposure to coumarins is associated with an increased risk for disturbances in development in school-age children. However, for the vast majority of children there is no clinical significant effect on growth and long-term development.

Leucine kinetics during simultaneously administered insulin and dexamethasone in preterm infants with severe lung disease

The objective of this study was to determine whether insulin administration would prevent the well-documented catabolic effect of dexamethasone given to preterm infants with chronic lung disease. We studied leucine metabolism in 11 very-low-birth-weight infants before dexamethasone treatment and on d 2, 4, and 7 thereafter. During the first 4 d of dexamethasone, insulin was administered i.v. at a dose of 0.5 (n = 7) or 1.0 (n = 5) IU/kg/d. Leucine turnover was not significantly different between d 0 (337 +/- 41.3 micromol leucine/kg/h), d 2 (288 +/- 27.2 micromol leucine/kg/h), d 4 (302 +/- 22.1 micromol leucine/kg/h), and d 7 (321 +/- 21.2 micromol leucine/kg/h), and neither was leucine breakdown (272 +/- 21.9 micromol leucine/kg/h on d 0, 225 +/- 21.5 micromol leucine/kg/h on d 2, 231 +/- 21 micromol leucine/kg/h on d 4, and 242 +/- 17.6 micromol leucine/kg/h on d 7). Weight gain rates were significantly lower during the first week of dexamethasone treatment compared with the week before treatment or the second and third week. We conclude that during insulin and corticosteroid administration in very-low-birth-weight infants, no changes were observed in leucine kinetics in contrast to previous studies. The decrease in weight gain was not reversed.

In utero exposure to coumarins and cognition at 8 to 14 years old

OBJECTIVE

To assess the cognitive abilities in school-aged children who have been exposed to coumarins in utero.

BACKGROUND

Coumarin derivatives are an effective option for anticoagulant therapy in pregnant women. However, case reports describe anomalies of the fetal central nervous system after in utero exposure to coumarins. It is unclear whether prenatal exposure has an effect on cognitive functioning later in childhood.

METHODS

The exposed cohort consisted of 291 children from mothers who were prospectively registered because of coumarin treatment during pregnancy. The nonexposed cohort included 253 age-matched peers. An IQ was estimated using subtests of the Weschler Intelligence Scale for Children-Revised. Educational achievement was examined with tests for reading, spelling, and arithmetic. In addition, schoolteachers were asked to judge performance on language and arithmetic. The observers were not aware of the exposure status of the child.

RESULTS

No differences in mean IQ were found between the exposed and nonexposed cohort (mean difference: -1.1; 95% confidence interval [CI]: -3.2-1.1), but an IQ score below 80 was found in 11 children in the exposed compared with 3 children in the nonexposed cohort (odds ratio [OR] = 3.1; CI: 0.8-11.6). Regarding the tests for educational achievement, exposed children as a group performed as well as nonexposed controls. Exposed boys, in comparison with nonexposed boys, showed a higher frequency of poor performance on reading (OR = 2.9; CI: 1.1-7.4) and spelling (OR = 2.5; CI: 1.0-6.0).

CONCLUSION

Cognitive functioning in coumarin-exposed children does not differ from nonexposed controls, but a minority of children seem to be prone to the potential negative effects of coumarins during pregnancy.

Growth until puberty after in utero exposure to coumarins

Anticoagulation with coumarins is an effective therapy during pregnancy. Fetal exposure to coumarin derivatives during the first trimester, however, is associated with skeletal anomalies (warfarin or coumarin embryopathy). Information about long-term effects of prenatal coumarin exposure on the skeletal development is not available. We investigated growth and body proportions at school age of children exposed to coumarins in utero. A blind population-based cohort study was conducted on 307 exposed children and 267 non-exposed controls ages 8-15 years. The exposed cohort was based on a prospective registry of coumarin-treated pregnant women. Anthropometric data included height, weight, head circumference, and measurements to evaluate body proportions. The mean height of exposed children did not differ from that of the non-exposed children (mean difference 0.01 SD). In addition, no differences were found for the proportional measures. As a group, children exposed in the first trimester showed no evidence of growth impairment. Two children in this group, however, were born with signs of coumarin embryopathy and one of these displayed a deficit in height at school age. Long-term growth was not affected by a high cumulative dosage or exposure after the first trimester. We conclude that, when exposure during the first trimester is avoided, coumarin therapy during pregnancy has no demonstrable risk for the child's skeletal development.

Immunologic effects of background exposure to polychlorinated biphenyls and dioxins in Dutch preschool children

Prenatal exposure to polychlorinated biphenyls (PCBs) and dioxins is associated with changes in the T-cell lymphocyte population in healthy Dutch infants. We investigated whether these changes persist into later childhood and whether background exposure to PCBs and dioxins is associated with the prevalence of infectious or allergic diseases and humoral immunity at preschool age. The total study group consisted of 207 healthy mother-infant pairs. We estimated prenatal exposure to PCBs and dioxins by the sum of PCBs 118, 138, 153, and 180 (sigmaPCB) in maternal and cord plasma and in breast-fed infants by the dioxin, planar, and mono-ortho PCB toxic equivalent (TEQ) levels in human milk. At 42 months of age, current body burden was estimated by the PCB in plasma. We assessed the prevalence of infectious and allergic diseases by parent questionnaire, and measured humoral immunity by antibody levels for mumps, measles, and rubella after primary vaccination. We performed immunologic marker analyses of lymphocytes in a subgroup of 85 children. Prenatal PCB exposure was associated with an increased number of lymphocytes, T-cells, and CD3CD8(+) (cytotoxic), CD4(+)CD45RO(+) (memory), T-cell receptor (TcR) [alpha]ss(+), and CD3(+)HLA-DR(+) (activated) T cells and lower antibody levels to mumps and measles at preschool age. Adjusted for confounders, prenatal PCB exposure was associated with less shortness of breath with wheeze, and current PCB body burden was associated with a higher prevalence of recurrent middle-ear infections and of chicken pox and a lower prevalence of allergic reactions. A higher dioxin TEQ was associated with a higher prevalence of coughing, chest congestion, and phlegm. We conclude that in Dutch preschool children the effects of perinatal background exposure to PCBs and dioxins persist into childhood and might be associated with a greater susceptibility to infectious diseases. Common infections acquired early in life may prevent the development of allergy, so PCB exposure might be associated with a lower prevalence of allergic diseases.

Immunologic effects of background exposure to polychlorinated biphenyls and dioxins in Dutch preschool children

Prenatal exposure to polychlorinated biphenyls (PCBs) and dioxins is associated with changes in the T-cell lymphocyte population in healthy Dutch infants. We investigated whether these changes persist into later childhood and whether background exposure to PCBs and dioxins is associated with the prevalence of infectious or allergic diseases and humoral immunity at preschool age. The total study group consisted of 207 healthy mother-infant pairs. We estimated prenatal exposure to PCBs and dioxins by the sum of PCBs 118, 138, 153, and 180 (sigmaPCB) in maternal and cord plasma and in breast-fed infants by the dioxin, planar, and mono-ortho PCB toxic equivalent (TEQ) levels in human milk. At 42 months of age, current body burden was estimated by the PCB in plasma. We assessed the prevalence of infectious and allergic diseases by parent questionnaire, and measured humoral immunity by antibody levels for mumps, measles, and rubella after primary vaccination. We performed immunologic marker analyses of lymphocytes in a subgroup of 85 children. Prenatal PCB exposure was associated with an increased number of lymphocytes, T-cells, and CD3CD8(+) (cytotoxic), CD4(+)CD45RO(+) (memory), T-cell receptor (TcR) [alpha]ss(+), and CD3(+)HLA-DR(+) (activated) T cells and lower antibody levels to mumps and measles at preschool age. Adjusted for confounders, prenatal PCB exposure was associated with less shortness of breath with wheeze, and current PCB body burden was associated with a higher prevalence of recurrent middle-ear infections and of chicken pox and a lower prevalence of allergic reactions. A higher dioxin TEQ was associated with a higher prevalence of coughing, chest congestion, and phlegm. We conclude that in Dutch preschool children the effects of perinatal background exposure to PCBs and dioxins persist into childhood and might be associated with a greater susceptibility to infectious diseases. Common infections acquired early in life may prevent the development of allergy, so PCB exposure might be associated with a lower prevalence of allergic diseases.

Adrenal function in sick very preterm infants

Some very preterm neonates admitted to the neonatal intensive care unit show circulatory and respiratory problems that improve after administration of steroids. It is unclear whether these symptoms could be caused by adrenal insufficiency. The objective of our study was to investigate the cortisol levels and the cortisol release from the adrenals after ACTH in very preterm infants with and without severe illness and to find whether a relation exists between adrenal function and outcome. An ACTH test (0.5 microg) was performed on d 4 in 21 very preterm infants (gestational age, 25.6-29.6 wk; birth weight, 485-1265 g). Baseline cortisol and 17-hydroxyprogesterone (17OHP) levels and the cortisol levels 30, 60, and 120 min after ACTH administration were measured. The Score for Neonatal Acute Physiology was used to measure illness severity. All infants showed an increase in cortisol levels after ACTH, but the cortisol levels were significantly lower in the ventilated more severely ill infants. After adjusting for birth weight and gestational age, the mean baseline cortisol levels and cortisol/17OHP ratios were significantly lower and the 17OHP levels significantly higher in the ventilated infants compared with the nonventilated infants. Patients with an adverse outcome had significantly lower baseline cortisol/17OHP ratios and 60-min cortisol levels during ACTH testing (p = 0.002 and p = 0.03, respectively). These data suggest an insufficient adrenal response to stress in sick ventilated very preterm infants with gestational ages younger than 30 wk compared with nonventilated less sick preterm infants. Further studies are required to investigate whether supplementation with physiologic doses of hydrocortisone may benefit the outcome.

Treatment with exogenous surfactant stimulates endogenous surfactant synthesis in premature infants with respiratory distress syndrome

OBJECTIVE

Treatment of preterm infants with respiratory distress syndrome (RDS) with exogenous surfactant has greatly improved clinical outcome. Some infants require multiple doses, and it has not been studied whether these large amounts of exogenous surfactant disturb endogenous surfactant metabolism in humans. We studied endogenous surfactant metabolism in relation to different amounts of exogenous surfactant, administered as rescue therapy for RDS.

DESIGN

Prospective clinical study.

SETTING

Neonatal intensive care unit in a university hospital.

PATIENTS

A total of 27 preterm infants intubated and mechanically ventilated for respiratory insufficiency.

INTERVENTIONS

Infants received a 24-hr infusion with the stable isotope [U-13C]glucose starting 5.3 +/- 0.5 hrs after birth. The 13C-incorporation into palmitic acid in surfactant phosphatidylcholine (PC) isolated from serial tracheal aspirates was measured. Infants received either zero (n = 5), one (n = 4), two (n = 15), or three (n = 3) doses of Survanta (100 mg/kg) when clinically indicated.

MEASUREMENTS AND MAIN RESULTS

Using multiple regression analysis, the absolute synthesis rate (ASR) of surfactant PC from plasma glucose increased with 1.3 +/- 0.4 mg/kg/day per dose of Survanta (p = .007) (mean +/- SEM). The ASR of surfactant PC from glucose was increased by prenatal corticosteroid treatment with 1.3 +/- 0.4 mg/kg/day per dose corticosteroid (p = .004), and by the presence of a patent ductus arteriosus with 2.1 +/- 0.7 mg/ kg/day (p = .01).

CONCLUSION

These data are reassuring and show for the first time in preterm infants that multiple doses of exogenous surfactant for RDS are tolerated well by the developing lung and stimulate endogenous surfactant synthesis.

The effect in premature infants of prenatal corticosteroids on endogenous surfactant synthesis as measured with stable isotopes

Most in vitro studies show that prenatal administration of corticosteroids stimulates the synthesis of surfactant phosphatidylcholine (PC), but studies in animals are controversial. Whether prenatal corticosteroids stimulate surfactant PC synthesis in humans has not been studied. We studied endogenous surfactant PC synthesis in relation to prenatal corticosteroid treatment in 27 preterm infants with respiratory distress syndrome. Infants received a 24-h infusion of the stable isotope [U-(13)C]glucose, starting approximately 5 h after birth. We measured (13)C-incorporation into palmitic acid in surfactant PC from serial tracheal aspirates and in plasma triglycerides and phospholipids by isotope-ratio mass spectrometry. Premature infants had received either zero (n = 11), one (n = 4), or two doses (n = 12) of prenatal betamethasone (12 mg intramuscularly). The fractional synthesis rate (FSR) of surfactant PC from glucose was 1.7 +/- 0.3%/d without corticosteroid treatment, 2.9 +/- 1.4%/d with one dose of prenatal corticosteroid, and 5.8 +/- 1.3%/d after two doses of prenatal corticosteroid. Using multiple regression analysis, we found that the FSR of surfactant PC increased by 40% (confidence interval: 7 to 82%/d, p < 0.02) per dose of corticosteroid and doubled after two doses of corticosteroid. The (13)C-enrichment of plasma triglycerides and phospholipids was not increased by corticosteroid. These data show for the first time that prenatal corticosteroid treatment stimulates surfactant synthesis in the preterm infant.

Behavioural outcome of school-age children after prenatal exposure to coumarins

In utero exposure to coumarin derivatives may affect the development of the central nervous system of the child, irrespective of the period of exposure in pregnancy. Little is known about effects on development in the long term. The aim of the present study was to determine whether prenatal exposure to coumarins affects behavioural outcome in children at school age. Behavioural outcome was assessed in a cohort of 305 exposed children, aged 7-15 years. Findings were compared with those in a cohort of 263 non-exposed controls, matched for sex, age, and demographic region. Behaviour was rated by parents and teachers using standardized questionnaires: the Groningen Behaviour Checklist Family situation (GBF) and the Groningen Behaviour Checklist School situation (GBS), respectively. The findings of the GBF were supported by the results of the GBS, filled in by teachers who were blind for the exposure status of the child. In comparison to the non-exposed children, the coumarin-exposed children scored lower on the cluster 'positive task orientation' (GBF P<0.05, GBS P<0.01), they scored higher on 'emotional instability' (GBF P<0.001, GBS P<0.05), and they had more problems on the social clusters (P<0.01). Based on the results of both questionnaires, we conclude that behavioural development may be negatively influenced in school-age children after in utero exposure to coumarins, leading to less favourable task-oriented and social-emotional behaviour. However, the frequency of clinically relevant 'problem behaviour' (GBF) was not increased in relation to coumarin exposure, the odds ratio was 1.2 (CI(95) 0.7-1.8).

Neonatal blood lymphocyte subpopulations: a different perspective when using absolute counts

We compared the absolute counts of lymphocyte subpopulations in 15 neonates, and 9 adults using the whole lysed blood technique with 15 different triple immunostainings. To obtain accurate absolute lymphocyte counts in neonatal cord blood samples, the flow cytometric 'lympho-gate' was corrected for the erythroid cell contamination by normoblasts and unlysed erythrocytes. In contrast to earlier studies where relative frequencies were reported, we found that the major difference between neonatal and adult lymphocyte subpopulations concerned the much larger pool of naive 'untriggered' cells in neonates, standby for participation in primary immune responses.

Exogenous surfactant kinetics in infant respiratory distress syndrome: A novel method with stable isotopes

Little is known about surfactant metabolism in newborn infants, since radioactive isotopes cannot be used in humans. We describe here a new method for studying exogenous surfactant pharmacokinetics in vivo. We measured surfactant half-life, pool size, and turnover time in eight preterm infants (gestational age: 30 +/- 2 wk; birth weight: 1,416 +/- 202 g) who were mechanically ventilated because of infant respiratory distress syndrome. We administered two doses of 100 mg/kg each of a natural porcine surfactant with (13)C-labeled dipalmitoylphosphatidylcholine as a tracer. The (13)C enrichment of surfactant disaturated phosphatidylcholine (DSPC) was measured in serial tracheal aspirates by gas chromatography-mass spectrometry. The DSPC half-life was 34.2 +/- 9.4 h (mean +/- SD; range: 21.8 to 45.9 h). The apparent DSPC pool sizes were 5.8 +/- 6.1 mg/kg (range: 0.1 to 17.0 mg/kg) and 17.3 +/- 13.6 mg/kg (range: 3.3 to 41.0 mg/kg) at the time of the first and second surfactant doses, respectively. We present a novel and safe method that allows the tracing of exogenous surfactant phosphatidylcholine, the major lipid component of pulmonary surfactant, in infants who receive exogenous surfactant. This method could be a valuable tool for studying: (1) therapies that enhance lung/surfactant maturation; (2) the dosing and timing of surfactant therapy in different lung diseases; and (3) the comparison of different surfactant preparations.

Short-term growth and substrate use in very-low-birth-weight infants fed formulas with different energy contents

BACKGROUND

Currently available preterm formulas with energy contents of 3350 kJ (800 kcal)/L promote weight and length gain at rates at or above intrauterine growth rates but disproportionately increase total body fat.

OBJECTIVE

The objective of this study was to determine whether fat accretion in formula-fed, very-low-birth-weight (VLBW) infants could be decreased and net protein gain maintained by reducing energy intakes from 502 kJ (80 kcal)*kg(-)(1)*d(-)(1) [normal-energy (NE) formula] to 419 kJ (100 kcal)*kg(-)(1)*d(-)(1) [low-energy (LE) formula] while providing similar protein intakes (3.3 g*kg(-)(1)*d(-)(1)).

DESIGN

The study was a randomized, controlled trial enrolling 20 appropriate-for-gestational-age (AGA) and 16 small-for-gestational-age (SGA) VLBW infants (mean birth weight: 1.1 kg; mean gestational age: 31 wk); energy expenditure and nutrient balance were measured at 4 wk of age and anthropometric measurements were made when infants weighed 2 kg.

RESULTS

The percentage of fat in newly formed tissue was significantly lower in AGA infants fed the LE formula (n = 9) than in those fed the NE formula (n = 10) (9% compared with 23%; analysis of variance, P = 0.001). Energy expenditure was higher in AGA infants fed the NE formula than in those fed the LE formula. Skinfold thickness was markedly lower in AGA infants fed the LE formula than in those fed the NE formula, resulting in a lower estimated percentage body fat (8.0 +/- 1.9% and 10.8 +/- 3.5%, respectively; P < 0.05). Three of 6 SGA infants fed the LE formula were excluded during the study because of poor weight gain.

CONCLUSIONS

Body composition can easily be altered by changing the energy intakes of formula-fed VLBW infants. Energy intakes in these infants should be >419 kJ (100 kcal)*kg(-)(1)*d(-)(1).

The contribution of newly synthesized cholesterol to bile salt synthesis in rats quantified by mass isotopomer distribution analysis

A new stable isotope procedure has been developed and validated in rats, applying [1-(13)C]acetate infusion to quantify the production of bile salts from de novo synthesized cholesterol making use of the mass isotopomer distribution analysis (MIDA) principle. Ions (m/z) 458-461, 370-373 and 285-288 were monitored by GC/MS (EI-mode) for the methyl trimethylsilylether derivatives of cholate, chenodeoxycholate and beta-muricholate, respectively. Rats with intact exteriorized enterohepatic circulation and rats with chronic bile diversion were infused with [1-(13)C]acetate for up to 14 h. After 10 h of infusion the enterohepatic circulation of the intact group was interrupted to deplete the existing bile salt pool (acute bile diversion). The fractions of biliary cholesterol and individual bile salts derived from newly synthesized cholesterol were determined by MIDA at t=14 h. In rats with acute bile diversion, these fractions were 20, 25, 27 and 23% for biliary cholesterol, cholate, chenodeoxycholate and beta-muricholate, respectively. After bile diversion for 8 days to induce hepatic cholesterol and bile salt synthesis, these fractions increased significantly to 32, 47, 41 and 47%, respectively. Calculated enrichments of the acetyl-CoA precursor pools were similar for all bile salts and biliary cholesterol within the two rat groups. However, chronic enterohepatic interruption decreased the acetyl-CoA pool size almost two-fold. We conclude that MIDA is a validated new stable isotope technique for studying the synthetic pathway from acetyl-CoA to bile salts. This technique provides an important new tool for studying bile salt metabolism in humans using stable isotopes.

Metabolism of endogenous surfactant in premature baboons and effect of prenatal corticosteroids

We studied the synthesis of surfactant and the effect of prenatal betamethasone treatment in vivo in very preterm baboons. Ten pregnant baboons were randomized to receive either betamethasone (beta) or saline (control) 48 and 24 h before preterm delivery. The newborn baboons were intubated, treated with surfactant, and ventilated for 6 d. They received a 24-h infusion with the stable isotope [U-(13)C]glucose as precursor for the synthesis of palmitic acid in surfactant phosphatidylcholine (PC). Palmitic acid in surfactant PC became enriched 27 +/- 2 h after the start of the isotope infusion and was maximally enriched at 100 +/- 4 h. The fractional synthesis rate of PC palmitate in the beta group (1.5 +/- 0.2%/d) was increased by 129% above control (0.7 +/- 0.1%/d) (p < 0.02, Mann- Whitney U test). The absolute synthesis rate of PC in the beta group [1.6 +/- 0.3 micromol/kg/d] was increased by 128% above controls [0.7 +/- 0.2 micromol/kg/d] (p < 0.02). These data show that the synthesis of endogenous surfactant from plasma glucose as precursor is a slow process. It is shown, for the first time in vivo, that prenatal glucocorticosteroids stimulate the synthesis of surfactant PC in the very premature baboon.

Validation in an animal model of the carbon 13-labeled mixed triglyceride breath test for the detection of intestinal fat malabsorption

OBJECTIVE

To determine, in a rat model of fat malabsorption, the potency of the carbon 13-labeled mixed triglyceride ((13)C-MTG) breath test as a noninvasive, patient-friendly replacement for classic fat balance studies.

STUDY DESIGN

Comparison of the percentage of fat absorption, detected by fat balance, with the (13)CO(2) recovery of the (13)C-MTG breath test in rats fed high-fat chow and varying amounts of the lipase inhibitor, orlistat (0, 50, 200, and 800 mg per kilogram of chow), for 5 days.

RESULTS

On orlistat administration, total fat absorption decreased from 80.2% +/- 2.2% to 32.8% +/- 3.7% (mean +/- SEM, 0 mg and 800 mg of orlistat per kilogram of chow, respectively; P <.001). Correspondingly, breath (13)CO(2) recovery from (13)C-MTG at 6 hours decreased from 84.5% +/- 7.8% to 42.0% +/- 1.5% of the dose (0 mg and 800 mg of orlistat per kilogram of chow, respectively; P <.001). The 6-hour recovery of breath (13)CO(2) appeared to be highly correlated with the percentage of fat absorption (r = 0.88, P <.001). In rats with fat absorption higher than 70%, however, the coefficient of variation of the (13)C-MTG breath test was 3-fold larger than that of the fat balance.

CONCLUSIONS

The (13)C-MTG breath test could potentially replace the fat balance method for comparing fat absorption efficacy between groups. Yet, a considerable interindividual variation of the (13)C-MTG breath test under conditions of relatively mild fat malabsorption does not support its application for diagnostic purposes in individuals.

Endogenous surfactant metabolism in critically ill infants measured with stable isotope labeled fatty acids

Little is known about endogenous surfactant metabolism in infants, because radioactive isotopes used for this purpose in animals cannot be used in humans. We developed a novel and safe method to measure the endogenous surfactant kinetics in vivo in humans by using stable isotope labeled fatty acids. We infused albumin-bound [U-13C]palmitic acid (PA) and [U-13C]linoleic acid (LLA) for 24 h in eight critically ill infants (mean+/-SD: weight: 3.7+/-1.3 kg: age: 51.3+/-61.6 d) who required mechanical ventilation. The 13C enrichment of PA and LLA in surfactant phosphatidylcholine (PC), obtained from tracheal aspirates, was measured by gas chromatography combustion interface-isotope ratio mass spectrometry. We measured a significant incorporation of both 13C-PA and 13C-LLA into surfactant PC. PC-PA and PC-LLA became enriched after 8.7+/-4.9 h (range: 3.4-17.3) and 10.0+/-7.2 h (range: 3.0-22.4), respectively; the times at maximum enrichment were 49.2+/-8.9 and 45.6+/-19.3 h, respectively. The fractional synthesis rate of surfactant PC-PA ranged from 0.4 to 3.4% per h, whereas the fractional synthesis rate of PC-LLA ranged from 0.5 to 3.8% per h. The surfactant PC-PA and PC-LLA half-lives ranged from 16.8 to 177.7 and 23.8 to 144.4 h, respectively. This method provides new data on surfactant metabolism in infants requiring mechanical ventilation. We found that synthesis of surfactant from plasma PA and LLA is a slow process and that there were marked differences in PC kinetics among infants. This variability could be related to differences in lung disease and could affect the clinical course of the respiratory failure.

Effects of environmental exposure to polychlorinated biphenyls and dioxins on cognitive abilities in Dutch children at 42 months of age

OBJECTIVE

To study possible adverse effects of environmental exposure to polychlorinated biphenyls (PCB) and dioxins on cognitive functioning in young children.

METHODS

In a follow-up of the Dutch PCB/Dioxin study, cognitive abilities were assessed with the Kaufman Assessment Battery for Children in 42-month-old children (n = 395). In a subgroup (n = 193) verbal comprehension was assessed with the Reynell Language Developmental Scales. Prenatal PCB exposure was estimated from the sum of PCBs 118, 138, 153, and 180 (SigmaPCB) in maternal plasma. Lactational exposure was assessed from breast milk PCB and dioxin concentrations, multiplied by the number of weeks of breast-feeding. Current PCB body burden was estimated from SigmaPCB in 42-month-old plasma samples.

RESULTS

After adjustment was done for covariables, maternal SigmaPCB was associated with lower scores on the overall cognitive and sequential and simultaneous processing scales of the Kaufman Assessment Battery for Children (all P <.05). The highest exposed group (SigmaPCB >/= 3 microg/L) scored 4 points lower on all 3 scales of the K-ABC when compared with the lowest exposed group (SigmaPCB < 1.5 microg/L). Both lactational exposure and current exposure to PCBs and dioxins were not related to 42-month cognitive performance.

CONCLUSIONS

In utero exposure to "background" PCB concentrations is associated with poorer cognitive functioning in preschool children. Children of mothers at the upper end of exposure are especially at risk. Therefore maternal PCB body burden should be reduced, and breast-feeding should not be discouraged.

Dietary exposure to polychlorinated biphenyls and dioxins from infancy until adulthood: A comparison between breast-feeding, toddler, and long-term exposure

Food is the major source for polychlorinated biphenyl (PCB) and dioxin accumulation in the human body. Therefore, investigating food habits from early ages until reproductive age (25 years) is important in order to assess exposure risk for the next generation. The objective of this study was to assess the PCB/dioxin exposure and the relative contribution of different foods to total exposure during preschool age. Particularly, the importance of lactational PCB/dioxin exposure vs. dietary exposure until adulthood was investigated. A cohort of 207 children was studied from birth until preschool age. Based on 3 planar PCBs and 17 2,3,7,8-substituted dibenzo-para-dioxins (PCDDs) and dibenzofurans (PCDFs) measured in breast milk, a model was developed to calculate the cumulative toxic equivalent (TEQ) intake during breast-feeding (0-1 year). In 3. 5-year-old children, daily dietary intake of planar PCB-TEQ and dioxin-TEQ was measured with a validated food questionnaire. Cumulative TEQ intake from 1 to 5 years was estimated using the PCB- and dioxin-TEQ intake measured with the food questionnaire. Cumulative TEQ intake from 6 to 25 years was estimated using national food consumption and contamination data of PCB- and dioxin-TEQ intake. In toddlers, dairy products contributed 43% to PCB-TEQ and 50% to dioxin-TEQ intake. Meat and meat products contributed 14% and 19%, respectively, and processed foods 23% and 15%, respectively. Breast-feeding for 6 months contributed to the cumulative PCB/dioxin TEQ intake until 25 years of age, 12% in boys and 14% in girls. The daily TEQ intake per kilogram body weight is 50 times higher in breast-fed infants and three times higher in toddlers than in adults. Long-term dietary exposure to PCBs and dioxins in men and women is partly due to breast-feeding (12 and 14%, respectively). After weaning, dairy products, processed foods, and meat are major contributors of PCB and dioxin accumulation until reproductive age. Instead of discouraging breast-feeding, maternal transfer of PCBs and dioxins to the next generation must be avoided by enforcement of strict regulations for PCB and dioxin discharge and by reducing consumption of animal products and processed foods in all ages.

Non-invasive detection of low-intestinal lactase activity in children by use of a combined 13CO2/H2 breath test

BACKGROUND

The aim of the study was to diagnose hypolactasia with a higher accuracy than with the traditional H2 breath test.

METHODS

We used a combined 13C-lactose 13CO2/H2 breath test, which was performed in 33 patients in whom lactase activity was measured.

RESULTS

Lactase activity was reduced in 13 cases. The sensitivity and specificity of the H2 test were 54% and 90%; those of the 13CO2 test 69% and 70%. False-negative results did not always occur in the same patients. In five of six patients with both test results abnormal, lactase activity was low. In 13 of 15 patients with both test results normal, lactase activity was normal. In 6 of 12 cases with only 1 test abnormal, lactase activity was low.

CONCLUSION

The combined H2/13CO2 breath test (sensitivity, 85%; specificity, 65%) is more adequate for diagnosis of hypolactasia than the H2 breath test alone.

Effects of environmental exposure to polychlorinated biphenyls and dioxins on birth size and growth in Dutch children

Lower birth weight and growth retardation has been found in studies with laboratory animals, in children born of mothers exposed to accidental high levels of polychlorinated biphenyls (PCBs) and related compounds, and in children born of mothers who consumed PCB-contaminated fish. The effect of background exposure to PCBs and dioxins on birth size and growth in human newborns, however, is still unknown. This study examined birth size and postnatal growth of term newborns in relation to their background PCB and dioxin exposure. Birth weight and weight, length, and head circumference were measured at 10 d and 3, 7, 18, and 42 mo of age in 207 children, of whom 105 were breast-fed and 102 were formula-fed during infancy. The effect of in utero exposure to PCBs on birth size, assessed by cord and maternal plasma PCB levels, was investigated in the whole group. The effect of prenatal PCB exposure on postnatal growth was studied in the formula-fed group, whereas the effect of prenatal as well as lactational exposure to PCBs and dioxins on postnatal growth was studied in the breast-fed group. After adjustment for covariates, cord and maternal plasma PCB levels where both negatively associated with birth weight. Infants with high cord plasma PCB levels (P90 = 0.80 microL) weighed 165 g less compared with infants with low cord plasma PCB levels (P10 = 0.20 microg/L). Cord and maternal plasma PCB levels where both significantly associated with lower growth rate, defined as change in SD score (SDS) of weight, length, and head circumference from birth to 3 mo in the formula-fed group (all p values <0.05). No negative effects of prenatal PCB exposure on growth rate were found from 3 to 42 months of age. Postnatal PCB and dioxin exposure was not negatively associated with growth rate in the breast-fed group. In utero exposure to environmental levels of PCBs is negatively associated with birth weight and postnatal growth until 3 mo of age. Although this growth delay was described in healthy term born infants, intrauterine and postnatal growth retardation are potentially harmful to the developing human and should be avoided by reducing maternal PCB and dioxin body burden, and consequently fetal exposure to these pollutants.

Endogenous surfactant turnover in preterm infants measured with stable isotopes

We studied surfactant synthesis and turnover in vivo in preterm infants using the stable isotope [U-13C]glucose, as a precursor for the synthesis of palmitic acid in surfactant phosphatidylcholine (PC). Six preterm infants (birth weight, 916 +/- 244 g; gestational age, 27.7 +/- 1.7 wk) received a 24-h [U-13C]glucose infusion on the first day of life. The 13C-enrichment of palmitic acid in surfactant PC, obtained from tracheal aspirates, was measured by gas chromatography-combustion interface-isotope ratio mass spectrometry. We observed a significant incorporation of carbon-13 from glucose into surfactant PC palmitate. PC palmitate became enriched after 19.4 +/- 2.3 (16.5 to 22.3) h and reached maximum enrichment at 70 +/- 18 (48 to 96) h after the start of the label infusion. The fractional synthesis rate (FSR) of surfactant PC palmitate from glucose was 2.7 +/- 1.3%/d. We calculated the absolute production rate of surfactant PC to be 4.2 mg/kg/d, and the half-life to be 113 +/- 25 (87 to 144) h. Data on endogenous surfactant production and turnover were obtained for the first time in human infants with the use of stable isotopes. This novel and safe method could be applied to address many important issues concerning surfactant metabolism in preterm infants, children, and adults.

Neurological condition in 42-month-old children in relation to pre- and postnatal exposure to polychlorinated biphenyls and dioxins

Adverse neurological effects of exposure to PCBs have been found up to 18 months of age. Now we report on the effect of pre- and postnatal exposure to PCBs and dioxins on the neurological condition at 42 months of age. For this purpose, PCB levels were determined in cord and maternal plasma, and used as a measure of prenatal exposure. Breast milk was analyzed for PCBs and dioxins. In addition, PCBs were determined in plasma sampled from the child at 42 months of age. We evaluated the neurological condition of 394 children using the Touwen/Hempel method. After adjustment for covariates, neither prenatal PCB exposure nor postnatal exposure to PCBs and dioxins was found to be related to the neurological condition at 42 months of age.

Fibre optic versus conventional phototherapy for hyperbilirubinaemia in preterm infants

Studies comparing efficacy of fibre optic phototherapy to conventional phototherapy are performed mostly in term infants and give conflicting results. This randomized prospective study compares efficacy of fibre optic phototherapy using the Ohmeda Biliblanket device to conventional fluorescent phototherapy in preterm infants. A total of 124 preterm infants with a nonhaemolytic hyperbilirubinaemia were evaluated. Stratification at randomisation was performed according to birth weight ( < 1000 g, 1000-1500 g or 1500-2000 g). Fifty-six infants received fibre optic and 68 conventional phototherapy. Efficacy was assessed by comparing the required duration of phototherapy. Median duration of phototherapy was 118 h and 114 h in the fibre optic and conventional groups respectively, the difference in which was not statistically significant. The median durations were also not significantly different within the separate weight groups. The number of infants requiring exchange transfusions was similar in both treatment groups.

CONCLUSION

The efficacy of fibre optic phototherapy in preterm infants is comparable to conventional phototherapy.

Intestinal absorption of long-chain polyunsaturated fatty acids in preterm infants fed breast milk or formula

The importance of long-chain polyunsaturated fatty acids (LCPs) in the development of preterm infants is now well accepted but the source of dietary LCPs to be added to infant formulas remains controversial. We measured dietary intakes, fecal output, and percentages of intestinal absorption of n-6 and n-3 LCPs in healthy preterm infants fed exclusively preterm breast milk (PBM; n = 20), formula without LCPs added (NLCPs; n = 19), formula with LCPs derived from phospholipids (PL-LCPs; n = 19), or formula with LCPs from triacylglycerols (TG-LCPs; n = 19). Intestinal absorption of arachidonic acid was not different in the four groups but docosahexaenoic acid was better absorbed from PL-LCPs than from PBM (88.3 +/- 1.8% compared with 78.4 +/- 4.0%, P < 0.05) Total absorption of n-6 LCPs was not different between groups but total n-3 LCPs were better absorbed from PL-LCPs than from PBM or TG-LCPs (88.7 +/- 1.9%, 79.2 +/- 4.4%, and 80.4 +/- 2.2%, respectively). In conclusion, docosahexaenoic acid and arachidonic acid were absorbed as efficiently from TG-LCPs formula as from breast milk fat. Absorption of docosahexaenoic acid and n-3 LCPs was greater from PL-LCPs formula than from PBM or TG-LCPs formula.

Plasma polychlorinated biphenyl levels in Dutch preschool children either breast-fed or formula-fed during infancy

OBJECTIVES

This study examined the influence of lactational and in utero exposure to polychlorinated biphenyls (PCBs) on plasma PCB levels in children.

METHODS

Plasma PCB levels were measured in 173 children at 3.5 years, of whom 91 were breast-fed and 82 were formula-fed in infancy.

RESULTS

Median plasma PCB levels were 3.6 times higher in breast-fed children (0.75 microgram/L) than in their formula-fed peers (0.21 microgram/L). Breast-feeding period and breast-milk PCB levels were important predictors for PCB levels in the breast-fed group. For children in the formula-fed group, PCB levels were significantly related to their material plasma PCB levels.

CONCLUSIONS

PCB levels in Dutch preschool children are related to transfer of maternal PCBs; therefore, strategies should be aimed at reducing maternal PCB body burden.

Simultaneous measurement of the rates of appearance of palmitic and linoleic acid in critically ill infants

Lipolysis has been measured in humans by means of stable isotope techniques using labeled palmitic acid (PA) or glycerol as tracers. If other fatty acids (FA) such as linoleic acid (LLA) have the same rate of appearance (Ra) as PA and therefore contribute equally to oxidative and nonoxidative metabolism is unknown. We infused albumin-bound [U-13C]PA and [U-13C]LLA in seven critically ill infants (weight 3.6 +/- 1.3 kg, age 57 +/- 64 d) receiving 20.9 +/- 5.4 kcal. kg-1.d-1 of i.v. glucose only, and measured simultaneously the Ra of PA and LLA from the isotopic enrichment of plasma FFA by mass spectrometry. A needle biopsy of the s.c. adipose tissue was obtained for FA composition. PA in adipose tissue was higher than LLA (40 +/- 6.7 versus 5.4 +/- 3.2 mol %, p < 0.001). The Ra values of PA and LLA were 5.73 +/- 2.79 and 1.34 +/- 0.92 mumol.kg-1.min-1, respectively (p = 0.005). However, the ratio of the FA's Ra to their respective mol% values in adipose tissue was lower for PA than for LLA (0.15 +/- 0.06 versus 0.25 +/- 0.06, p = 0.02). The Ra of LLA acid was higher than could be expected from the FA composition of adipose tissue, thus indicating a preferential release of LLA during lipolysis. In critically ill infants receiving only i.v. glucose, the contribution of LLA to the oxidative and nonoxidative metabolism may be larger than what assumed from the FA composition of plasma and adipose tissue.

Structural position and amount of palmitic acid in infant formulas: effects on fat, fatty acid, and mineral balance

The structure of the triglycerides (TG) in human milk (HM) differs from those of vegetable oils used in infant formulas. In HM, palmitic acid is predominantly esterified to the center or beta-position of the TG, in vegetable oil, it is mainly at the external or alpha-positions. These differences in configuration affect intestinal fat absorption. Fat and mineral balances were investigated in three groups of 9 healthy term infants aged 5 weeks. Infants were randomly assigned to receive one of the three study formulas from birth: (a) formula beta, resembling the structure of HM fat most closely (24% palmitic acid, 66% esterified to beta-position), (b) formula intermediate (24% palmitic acid, 39% esterified to the beta-position), and (c) regular formula (20% palmitic acid; 13% esterified to the beta-position). Fat absorption was highest in infants fed the beta formula (97.6 +/- 0.9%), intermediate in those fed with the intermediate formula (93.0 +/- 1.8%), and lowest in infants receiving the regular formula (90.4 +/- 4.6%). Fecal calcium excretion was significantly lower in the beta group than in the other two groups (43.3 +/- 18.1 vs. 59.9 +/- 15.1 vs. 68.4 +/- 22.3 mg.kg-1.day-1 for beta, intermediate, and regular respectively). Dietary TG containing palmitic acid predominantly at the beta-position, as in HM, have significant beneficial effects on the intestinal absorption of fat and calcium in healthy term infants.

The very low birth weight premature infant is capable of synthesizing arachidonic and docosahexaenoic acids from linoleic and linolenic acids

Infants fed formulas devoid of long-chain polyunsaturated fatty acids (LCP) exhibit low plasma LCP concentrations and have poorer retinal and neurologic development in comparison with their human milk-fed counterparts. It is not known whether the low plasma LCP concentrations result from an impaired biosynthetic capacity, a high need or a low dietary intake. With stable isotope technology and high sensitivity tracer detection using gas chromatography-isotope ratio mass spectrometry we measured the conversion of [13C]linoleic acid (C18:2n-6) and [13C]linolenic acid (C18:3n-3) into their longer chain derivatives in five 1-mo-old formula-fed preterm infants (birth weight 1.17 +/- 0.12.kg and gestational age 28.4 +/- 1.3 wk). Carbon-13-labeled linoleic acid and inolenic were mixed with the formula and administered continuously for 48 h. Both tracers were rapidly incorporated in plasma phospholipids, and their metabolic products including arachidonic acid (C20:4n-6) and docosahexaenoic acid (C22:6n-3) became highly enriched. We demonstrate that the preterm infant is capable of synthesizing LCP from their 18-carbon precursors, and our data do not support the hypothesis that a reduced delta 6 desaturation is a main factor leading to low arachidonic acid and docosahexaenoic acid levels.

Effects of polychlorinated biphenyl/dioxin exposure and feeding type on infants' mental and psychomotor development

OBJECTIVE

To evaluate the effects of in utero and lactational exposure to polychlorinated biphenyls (PCBs) and dioxins on the mental and psychomotor development of infants.

DESIGN

Prenatal PCB exposure was estimated from the levels in maternal plasma during the last month of pregnancy. Postnatal PCB and dioxin exposure of breastfed infants was calculated from levels in human milk samples and the duration of breastfeeding. Infants were examined at 3, 7, and 18 months of age with the Bayley Scales of Infant Development.

SETTING

General community.

PARTICIPANTS

Voluntary sample of 207 mother-infant pairs. One hundred five infants were breastfed and 102 were bottle-fed.

INTERVENTIONS

None.

RESULTS

Higher in utero exposure to PCBs was associated with lower psychomotor scores at 3 months of age: a doubling of the PCB load resulted in a decrease of 3 points. Breastfed infants scored significantly higher on the psychomotor score at 7 months of age, compared with formula-fed infants. However, when corrected for confounders, the psychomotor score of the 66% highest-exposed breastfed infants ( > 756 pg total PCB-dioxin toxic equivalent) was negatively influenced by this postnatal exposure to PCBs and dioxins, and was comparable to the psychomotor score of the formula-fed infants. Breastfed infants also scored higher on the mental scale at 7 months of age in a dose-dependent way. There was no significant influence of the perinatal PCB and dioxin exposure on the mental outcome at 3 and 7 months of age. At 18 months of age neither the mental nor the psychomotor score was related to perinatal PCB or dioxin exposure, nor to the duration of breastfeeding.

CONCLUSIONS

Prenatal PCB exposure has a small negative effect on the psychomotor score at 3 months of age. PCB and dioxin exposure through breastfeeding has an adverse effect on the psychomotor outcome at 7 months of age. The mental outcome at 7 months of age is positively influenced by breastfeeding per se; the perinatal exposure to PCBs and dioxins does not influence this outcome. At 18 months of age the development is affected neither by PCB and dioxin exposure nor by feeding type.

Plasma and red blood cell fatty acid of very low birth weight infants fed exclusively with expressed preterm human milk

The fatty acid composition of plasma phospholipids, triglycerides, sterol esters, and red blood cell phospholipids were determined at birth and again on d 7, 14, and 28 of life in 22 very low birth weight infants (birth weight 1180 +/- 290 g, gestational age 29.8 +/- 2.4 wk) fed exclusively with preterm human milk starting from the first hours postpartum. Milk intake was recorded daily, and intakes of fat and individual fatty acids were measured weekly. The intakes of linoleic acid and linolenic acid rose significantly during the study period, so did their incorporation into plasma and red blood cell lipids. The intakes of arachidonic acid (29.2 +/- 2.4 versus 30.4 +/- 2.1 mg.kg-1.day-1) and docosahexaenoic acid (18.8 +/- 1.7 versus 17.0 +/- 1.2 mg.kg-1.day-1) on d 14 and 28, respectively, were not different; however, their plasma levels declined significantly. The percentages of arachidonic acid declined in all plasma and red blood cell lipids, whereas the fall of docosahexaenoic acid was more notable in triglycerides and sterol esters, intermediate in plasma phospholipids, and less pronounced in red blood cell phospholipids. We conclude that very low birth weight infants fed exclusively with preterm milk, which unlike most preterm formulas contains long chain polyunsaturated fatty acids, exhibit declining levels of arachidonic acid and docosahexaenoic acid from birth up to 28 d of life.

Ceftazidime pharmacokinetics in preterm infants: effects of renal function and gestational age

OBJECTIVE

The objectives of this study were (1) to determine the effects of gestational age on ceftazidime pharmacokinetics in the preterm infant, (2) to relate these effects to changes in glomerular filtration rate (GFR), and (3) to establish appropriate dosage recommendations for preterm infants on day 3 of life.

METHODS

Multiple-dose pharmacokinetics of ceftazidime (administered twice daily in a 25 or 50 mg/kg body weight intravenous dose) were evaluated in 136 preterm infants on day 3 of life. Blood samples were collected from an arterial catheter 0, 1/2, 1, 2, 4, 8, and 12 hours after the intravenous dose. An HPLC method was used to determine ceftazidime concentrations in serum. The GFR was studied simultaneously by means of the 24-hour continuous inulin infusion technique.

RESULTS

The total body clearance, volume of distribution, and elimination serum half-life of ceftazidime (mean +/- SD) were 55.7 +/- 34.4 ml/hr (37.3 +/- 11.9 ml/hr/kg), 496 +/- 228 ml (350 +/- 96 ml/kg), and 6.95 +/- 2.32 hours, respectively. The mean +/- SD peak and trough levels were 114.9 +/- 39.4 and 33.9 +/- 17.8 mg/L. All infants had a serum trough level above 5 mg/L. Clearance and volume of distribution of ceftazidime and GFR increased significantly with increasing gestational age, whereas serum trough levels and serum half-life of ceftazidime decreased significantly with increasing gestational age. Ceftazidime clearance increased significantly with increasing GFR. Prenatal exposure to indomethacin resulted in significantly lower GFR values and ceftazidime clearances.

CONCLUSIONS

Dosage recommendations for ceftazidime administration in preterm infants during the first week of life should be based on gestational age and GFR. Additional adjustments in dosage are indicated in preterm infants who are exposed prenatally to indomethacin.

Perinatal exposure to polychlorinated biphenyls and dioxins through dietary intake

Polychlorinated biphenyls (PCBs) and dioxins (polychlorinated dibenzo-p-dioxins and dibenzofurans) are potentially hazardous compounds. Since food is the major source (> 90%) for the accumulation of PCBs and dioxins in the human body, food habits in women determine the degree of fetal exposure and levels in human milk. In order to investigate an association between dietary intake and PCB and dioxin levels in human milk and PCB levels in maternal and cord plasma, the food intake of 418 Dutch women during pregnancy was recorded using semi-quantitative food frequency questionnaires. After adjusting for covariates, a weak association was found between the estimated dietary intake of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), dioxins, and planar PCBs and their corresponding levels in breast milk. The estimated dietary intake of 2,3,7,8-TCDD, dioxins, and planar PCBs was also related to the PCB levels in maternal and cord plasma. Dairy products accounted for about half and industrial oils for about a quarter of the estimated 2,3,7,8-TCDD, dioxin, and the planar PCB intake. It is concluded that the contribution of a pregnancy related diet to PCB and dioxin levels in human milk and to PCB levels in maternal and cord plasma is relatively low. Decrease of exposure to PCBs and dioxins of the fetus and the neonate probably requires long-term reduction of the intake of these pollutants. Substitution of normal cheese by low-fat cheese and the use of vegetable oils instead of fish oils in the preparation of foodstuffs by the food industry could contribute to a reduced intake of PCBs and dioxins.