Protein turnover rates in sick, premature neonates during the first few days of life.

Rates of protein turnover were measured in 19 infants during the first few days of life while they were receiving i.v. glucose. The technique consisted of a continuous i.v. infusion of L-[1-13C]leucine to measure whole body leucine flux and determination of total urinary nitrogen excretion to assess leucine oxidation rates. Subsequent to each of the studies, the decision to start total parenteral nutrition (TPN) was made by the clinician concerned, with the result that seven infants did not start TPN and 12 did. There were significantly greater urinary nitrogen excretion (p less than 0.001) and lower rates of whole body protein synthesis (p = 0.024) and breakdown (p = 0.015) in those who did start TPN compared with those who did not. The marked difference in nitrogen excretion between the two groups suggests that this could be a useful determinant for deciding which neonate should start TPN.     

Procalcitonin in preterm infants during the first few days of life: introducing an age related nomogram

OBJECTIVE: To determine normal concentrations of procalcitonin in preterm infants shortly after birth and to assess its accuracy in detecting bacterial infection. METHODS: Blood samples of 100 preterm infants were prospectively drawn during the first 4 days of life for determination of procalcitonin concentration. Infants were classified into four groups according to their sepsis status. RESULTS: Mean (SD) gestational age and birth weight were 32 (2.9) weeks and 1682 (500) g respectively. A total of 283 procalcitonin concentrations from healthy infants were plotted to construct nomograms of physiologically raised procalcitonin concentration after birth, stratified by two groups to 24-30 and 31-36 weeks gestation. The peak 95th centile procalcitonin concentration was plotted at 28 hours of age; values return to normal after 4 days of life. Only 12 infants were infected, and 13 of their 16 procalcitonin concentrations after birth were higher than the 95th centile, whereas samples taken at birth were lower. In a multivariable analysis, gestational age, premature rupture of membrane, and sepsis status influenced procalcitonin concentration independently, but maternal infection status did not. CONCLUSIONS: The suggested neonatal nomograms of preterm infants are different from those of term infants. Procalcitonin concentrations exceeding the 95th centile may be helpful in detecting congenital infection, but not at birth.     

Characteristics and functional properties of red cells during the first days of life.

In order to evaluate postnatal red blood cell (RBC) properties and whole-blood rheology, 36 healthy full-term newborn infants were tested twice (cord blood, 4th-day blood) for whole-blood flow rate, hematocrit, hemoglobin (Hb), RBC count, mean corpuscular volume, mean corpuscular Hb and its concentration, white blood cell and platelet count, plasma fibrinogen, erythrocyte glucose-6-phosphate dehydrogenase, glutathione peroxidase (GSH-Px), glutathione reductase, catalase and superoxide dismutase. Another 38 healthy full-term newborns were tested twice for separation of erythrocytes into fractions of different density. Healthy adults were taken as control. The results showed a decreased whole-blood flow rate in blood drawn on the 4th day with respect to cord blood. A multivariate analysis with flow rate as dependent variable demonstrated a significant positive correlation with GSH-Px on the 4th day. The assays of RBC densities showed a significant increase in the first 4 days.     

Cow milk protein antigens and antibodies in serum of premature infants during the first 10 days of life

Antigenic beta-lactoglobulin and alpha-casein were measured in the sera of 45 formula-fed infants of 31 to 41 weeks of gestation at 5 days and at 10 days of age. Quantitation was performed by a sensitive ELISA inhibition assay. On day 5 of life antigenic lactoglobulin was detected in 14 of 19 infants of less than 37 weeks gestation, but in only one of 10 infants of more than 36 weeks gestation. On day 10 of life the sera of all infants contained antigenic lactoglobulin. In contrast, on day 5 antigenic casein was present in four of 17 infants of less than 37 weeks gestation, but in 10 of 12 infants of the more mature group. On day 10 casein was detected in seven of 28 infants, with no difference between groups; anti-casein was found in eight of 12 infants. Infants of less than 37 weeks gestation have different absorption patterns than more mature infants do. "Gut closure" is an unlikely explanation for these findings.     

Calcium, sodium and potassium urinary excretion during the first five days of life in very preterm infants

BACKGROUND: Hypercalciuria has been associated with the risk of nephrocalcinosis and renal stones in both adults and children. Renal calcifications are frequently encountered in preterm infants because this particular population presents most of the risk factors of increased urinary calcium excretion. Urinary calcium excretion has been shown to correlate with sodium and potassium excretions in adult patients, but these correlations have not been demonstrated in the early neonatal period yet. OBJECTIVE: To define the relationship between calcium urinary excretion and sodium or potassium excretions in the first 5 days of life in preterm babies. METHODS: A prospective study was conducted in 16 preterm infants born before 32 weeks of gestation (body weight 1,373 +/- 310 g; gestational age 29.1 +/- 1.6 weeks). Fifteen consecutive 8-hour urine collections were performed for each infant from the 8th hour of life. A plasma sample was obtained at the end of each urine collection. Sodium, potassium, calcium and creatinine were measured in urine and blood samples as often as possible. RESULTS: (1) Urine sodium excretion was 6.56 +/- 4.35 mmol/kg per day. (2) Urinary calcium excretion was 5.9 +/- 5.4 mg/kg per day and the urinary calcium/creatinine ratio was 0.48 +/- 0.39 mg/mg. (3) Urinary calcium and sodium excretion were positively correlated (r = 0.65, p = 0.0001), while an inverse correlation was found between calcium and potassium excretion (r = 0.31, p = 0.004). CONCLUSION: The mean values of urinary calcium excretion and calcium/creatinine ratio observed in our population were higher than 4 mg/kg per day and 0.4 mg/mg, respectively, i.e. boundary values previously associated with an increased risk of nephrocalcinosis. We hypothesize that an increase in urinary sodium excretion in this population may facilitate calcium excretion.     

Sympathoadrenal activity in preterm infants during the first five days of life.

We measured plasma concentrations of epinephrine (E), norepinephrine (NE), 3,4-dihydroxyphenylacetic acid (DOPAC), and 3,4-dihydroxyphenylglycol (DHPG) as well as urinary concentrations of metanephrine (M), normetanephrine (NM) and 3-methoxy-4-hydroxymandelic acid (MOMA) on day 2 and day 5 in preterm infants; gestational age less than 30 weeks (G less than 30; n = 16) and gestational age 30-34 weeks (G 30-34; n = 19). Concentrations of E (0.00-2.28 nmol/l) and NE (0.6-9.1 nmol/l) in plasma were much lower than those previously reported during preterm and term delivery. The E:NE ratio decreased from 1:10 on day 2 to 1:30 on day 5, and the M:NM ratio decreased from 1:4 on day 2 to 1:8 on day 5, indicating relatively higher catecholamine secretion from the adrenals than from the sympathetic nerve terminals in preterm infants during postnatal adaptation. Plasma concentrations of DOPAC and DHPG were significantly higher in G less than 30 than in G 30-34 (DOPAC, p = 0.0494; DHPG, p = 0.0092), probably relating to a low urinary excretion rate of catecholamine metabolites in infants in G less than 30. Plasma and urinary concentrations of catecholamines and their metabolites varied considerably, and no significant correlations to postnatal events could be demonstrated.     

Transfusion in premature infants impairs production and/or release of red blood cells,white blood cells and platelets

OBJECTIVE: To examine whether red blood cell transfusion in infants with anaemia of prematurity alters peripheral counts of red blood cell precursors, total white blood cells and white cell differential and platelets. METHODOLOGY: In 18 consecutive stable premature infants with anaemia of prematurity, peripheral cell counts were prospectively recorded immediately before transfusion of 20 mL/kg packed red blood cells (given over 6 h), and at 48 h after completion of the transfusion. RESULTS: The median (interquartile range) haematocrit increased from 22.0% (21.3-24.0%) pre-transfusion to 37.0% (36.0-38.0%) post-transfusion (P < 0.001). Red-cell precursors decreased: median (interquartile range) reticulocytes from 3.7% (3.0-7.7%) to 3.7% (2.6-4.1%) (P = 0.03); and median (interquartile range) nucleated red blood cells from 0 G/L (0-0.2 G/L) to 0 G/L (0-0 G/L) (P = 0.03). The mean (SD) platelet count decreased from 420 G/L (154 G/L) to 313 G/L (101 G/L) (P = 0.001). The total white blood cell count and neutrophils did not change significantly; however, median (interquartile range) immature neutrophils decreased from 0.12 G/L (0.06-0.74 G/L) to 0.08 G/L (0.01-0.24 G/L) (P = 0.03). Lymphocytes, eosinophils, basophils and plasma cells remained unchanged. Monocytes increased (P = 0.01). CONCLUSIONS: Forty-eight hours after red blood cell transfusion to premature infants, there is an absolute decrease in red blood cell precursors, immature white blood cells and platelets, probably due to erythropoietin-suppression.     

Hydration during the first days of life and the risk of bronchopulmonary dysplasia in low birth weight infants

We conducted a case-control study of antecedents of bronchopulmonary dysplasia (BPD) in 223 infants enrolled in a prospective, randomized clinical trial of phenobarbital prophylaxis for intracranial hemorrhage. The trial took place at three Boston neonatal intensive care units between June 1981 and April 1984. The 76 babies with BPD had radiographic evidence of the condition and required oxygen therapy for 28 days or more. All 147 control babies survived until day 28 of life without meeting either of these criteria for BPD. Compared with control infants, those with BPD received greater quantities of total, crystalloid, and colloid fluids per kilogram per day in the first 4 days of life. In addition, infants with BPD generally had a net weight gain in the first 4 days of life in contrast to the normal pattern of weight loss seen in control infants. Finally, the infants with BPD were more likely to be given a clinical diagnosis of patent ductus arteriosus and to have received furosemide on days 3 and 4 of life. From these observations we infer that early postnatal phenomena such as excessive fluid therapy may be important in the pathogenesis of BPD.     

Addressing obesity in the first 1000 days in high risk infants: Systematic review

Early intervention is critical for addressing the challenge of childhood obesity. Yet many preventive interventions do not target infants most at risk of future overweight or obesity. This systematic review examines interventions delivered before 2 years that aim to ameliorate excess weight gain among infants at high risk of overweight or obesity, due to sociodemographic characteristics, parental weight or health status, infant feeding or health behaviours. We searched six databases for interventions: (a) delivered before age two, (b) specifically aimed at infants at high risk of childhood obesity and (c) that reported outcomes by weight status beyond 28 days. The search identified over 27,000 titles, and 49 papers from 38 studies met inclusion criteria: 10 antenatal interventions, 16 postnatal and 12 conducted both before and after birth. Nearly all targeted infant and/or maternal nutrition. Studies varied widely in design, obesity risk factors, outcomes and quality. Overall, nine interventions of varying quality reported some evidence of significantly improved child weight trajectory, although effects tended to diminish over time. Interventions that improved weight outcomes tended to engage parents for a longer period, and most offered health professional input and support. Two studies of limited quality reported significantly worse weight outcomes in the intervention group.     

Sodium and potassium concentrations in red blood cells and plasma in children with congenital heart defect

The sodium and potassium concentrations of the red blood cells and plasma were investigated in 93 children with cardiac disease, most of them with congenital heart defect, and in 48 healthy children of the same age. The red blood cell sodium and potassium concentrations were constant within a narrow range in normal subjects, but varied profoundly in pathological conditions. Digitalis treatment caused RBC Na+ and plasma K+ levels to increase and the RBC K+ level to decrease by blocking the Na+-K+ pump. The highest RBC Na+ concentration was observed in critically ill patients with congestive heart failure treated with digoxin. An augmented RBC sodium value was found in heart malformations with left to right shunt and in congestive cardiomyopathy that was not treated, whereas in patients with right to left shunt lower RBC sodium, higher RBC potassium and plasma potassium values were registered without any treatment. In cases of hyperkinetic circulation without any congenital heart defect the value of RBC sodium was definitely low. A low sodium and a high potassium level of the RBC were found after total correcting heart surgery. It is concluded that measurement of changes in sodium and potassium concentrations of the red blood cells is not a reliable method for assessment of the efficacy of digitalis treatment. The results point to the accompanying phenomena at a cellular level in heart disease.