Inflammatory cytokines in newborn infants.

Serum levels of IL-1beta, IL-6 and TNF-alpha were measured in 48 healthy, termed neonates on the 1st (N1), 5th (N5) and 40th (N40) day after birth, compared with those in maternal serum (MS), umbilical cord (UC) and adult controls. Cytokine values in N1 and N5 were significantly elevated, than those in UC and in controls (P<0.0001). IL-1beta and IL-6 declined significantly from N1 to N40 (P<0.0001), while TNF-alpha increased significantly from N1 to N5 and declined thereafter. MS infinity IL-1beta and IL-6, but not MS infinity TNF-alpha, were significantly higher than those of controls (P<0.0001). IL-1beta values depended on the mode of delivery. In conclusion, the increased concentrations of IL-1beta, IL-6 and TNF-alpha during the perinatal period might suggest their involvement in an inflammation-like process during normal parturition, and reflect also a newborn immune response to the stress of delivery and environmental changes.     

Evaluation of three antibiotic programs in newborn infants.

Emergence of gram-negative bacteria resistnant to a number of antibiotics in intensive care nurseries for neonates emphasizes the need for alternatives in antibiotic combinations. One commonly used combination, gentamicin-ampicillin, and two newer combinations, tobramycin-cephalothin and amikacinampicillin, were evaluated prospectively in 60 newborns in such a nursery. Subjects were randomly assigned to one of the above therapy groups. Dosages in mg/kg.d were 100 for ampicillin and cephalothin, 6 for gentamicin and tobramycin and 15 for amikacin. Aminoglycoside serum concentrations, clinical tolerance and toxicity were monitored. Aminoglycoside concentrations after intravenous administration of the drugs were within the expected range (gentamicin and tobramycin 4 to 6 microgram/mL and amikacin 15 to 20 microgram/mL). There was no hematologic, renal or hepatic toxicity attributable to antibiotic therapy and the combinations were tolerated equally; no bilirubin displacement was detected in vitro or in vivo.     

Alternatives to hexachlorophene bathing of newborn infants.

In controlled trials newborn infants were bathed with Lactacyd, pHisoHex, Hibitane, Lanohex or tap water. Bacteriologic samples were taken from three sites (groin, axilla and cord) immediately after birth, following an initial bath with one of the test agents, and on day 3 or 5 after a water bath. Initial bathing with all agents, including water, reduced the concentration of bacteria on the skin to a similar extent. However, comparisons of bacterial flora at birth versus those on days 3 and 5 indicated differences in the actions of the various agents on pathogenic and nonpathogenic organisms. Lactacyd and Hibitane appeared to be suitable alternatives to hexachlorophene in the control of pathogenic bacteria on the skin of newborns. However, their absorption and toxicity in the newborn are unknown and, unless use of a skin disinfectant is warranted, routine bathing of newborns with tap water appears to be satisfactory.     

Lymphocyte reactivity in pregnant women and newborn infants.

The mitotic response to phytohaemagglutinin (PHA) was determined in lymphocytes of mothers and their newborn infants obtained at delivery and seven days later by measuring the rate of 125 I-idoxuridine uptake into DNA in lymphocytes cultured in their own plasma and after washing and resuspension in fetal bovine serum. There was no difference in the unstimulated counts of maternal lymphocytes taken at delivery, whether unwashed or washed, compared with those from nonpregnant controls. With PHA stimulation the mitotic response of the maternal lymphocytes cultured in their own plasma was reduced compared with that of the control lymphocytes but washed maternal cells showed a similar response to the controls. These findings suggest that the reduced lymphocyte mitotic response to PHA in pregnancy is due to a plasma inhibitory factor This inhibition was not evident in maternal blood taken seven days after delivery. DNA synthesis in unstimulated cultures from newborn infants at birth and seven days after birth was greater than that in adult control cultures. With PHA stimulation the mitotic response of cord-blood lymphocytes cultured in their own plasma paralleled that of control lymphocytes but washed newborn cells showed a greater response. Thus plasma suppression similar to that observed in the mother seems also to affect infants at birth. This inhibition was not demonstrable in blood taken from infants of 7 days.     

Head measurements in newborn infants

Normal anthropometric standards for head length and head width expressed in absolute and index values were determined in 366 newborn infants born between 28 and 42 gestational weeks. Mean +/- 2 SD values are tabulated separately according to gestational age or birth weight. The findings suggest that breech presentation and cesarean section alone do not significantly influence the anthropometric indices of the head in the otherwise normal neonate.     

Blood pressure survey in a population of newborn infants.

Systolic blood pressure in the arm was measured in infants at the ages of 4 to 6 days and 5 to 7 weeks by the Doppler ultrasound technique. At the age of 4 to 6 days the mean blood pressure (+/- SE of mean) in 469 sleeping infants was 70-7 +/- 0-3 mm Hg, rising at 5 to 7 weeks to 89-7 +/- 0-9 mm Hg (in 144 infants). In 252 infants awake at 5 to 7 weeks blood pressure was 96-8 +/- 0-6 mm Hg. In 391 infants in whom measurements were made on both occasions blood pressure at 4 to 6 days was significantly related to blood pressure at 5 to 7 weeks. Thus those infants with relatively high blood pressures at 4 to 6 days showed a weak tendency to have relatively high blood pressures at 5 to 7 weeks. In this trend continues with age it would suggest that the tendency to develop hypertension may already be demonstrable at the age of 4 to 6 days.     

Metabolism of threonine in newborn infants

Threonine kinetics, threonine oxidative pathway, and the relationship between threonine and whole body protein turnover were quantified in 10 healthy term infants during the first 48 h after birth. The kinetic data were obtained 6 h after the last feed (fasting) and in response to formula feeding, using [U-(13)C(4),(15)N]threonine, [(2)H(5)]phenylalanine, and [(15)N]glycine tracers. The rate of carbon dioxide production (Vco(2)) and (13)C enrichment of the expired CO(2) were measured to quantify the rate of oxidation of threonine. The rate of appearance (R(a)) of threonine (136 +/- 37 micromol.kg(-1).h(-1)) was higher in newborn infants than that reported in adults. Formula feeding resulted in a significant decrease in threonine R(a) (P < 0.05). A significant positive correlation was seen between phenylalanine R(a) and threonine R(a), both during fasting and after formula feeding (r(2) = 0.65). In contrast to a 1:1 ratio of threonine and phenylalanine in mixed muscle protein, threonine R(a) relative to phenylalanine R(a) was 2.2 +/- 0.4. The fractional rate of threonine flux oxidized was 20% during fasting and 26% (P < 0.05) in response to nutrient administration. There was a significant correlation between plasma threonine concentration and threonine oxidation (r(2) = 0.75). No measurable incorporation of threonine in plasma glycine was seen. These data suggest that threonine is exclusively degraded by the glycine-independent serine/threonine dehydratase pathway. A higher flux of threonine relative to phenylalanine indicates higher turnover of threonine enriched proteins.     

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.