Bleomycin-detectable iron in the plasma of premature and full-term neonates.

The bleomycin assay measures non-transferrin-bound iron, able to catalyze free radical reactions, in human plasma. No bleomycin-detectable iron is present in plasma from healthy adults. However, plasma from 3/15 premature babies was positive in this assay. Plasma from 52 apparently-healthy term babies was analyzed and 11 were positive in the bleomycin assay. Hence not only some premature but also some full-term apparently-healthy babies may be at risk of severe oxidative damage.

C3 and C4 complement components and acute phase proteins in late pregnancy and parturition.

To determine whether changes in complement or acute phase proteins can predict onset of labour, complement components C3 and C4, alpha-1-antitrypsin, and alpha-1-acid glycoprotein were measured serially in the third trimester of pregnancy and throughout labour in 11 women. C-reactive protein (CRP) concentration, C3 conversion products, and factor B activation was studied in five pregnancies one week before delivery, during labour, and six weeks after delivery. C3, C4, and CRP concentrations were unchanged and there was no evidence of complement conversion, either immediately before or during labour, by the classical or alternative pathways. A wide variation among subjects but a small variation within subjects for all proteins assayed was noted. It is important to use serial rather than cross sectional biochemical data when determining normal physiological patterns in pregnancy. The proteins measured have no predictive value in the timing of the onset of normal labour.

Plasma ionised calcium in preterm infants: comparison with adults.

Plasma calcium (ionised and total) and albumin concentrations and pH were measured in preterm infants and in healthy adults and patients dependent on respirators. Plasma ionised calcium and total calcium values fell during the first week after birth and subsequently rose. Plasma ionised calcium concentrations in preterm infants were higher than those found in both healthy and sick adults. This difference was only partially explained by the lower blood pH in the infant population. There was no correlation between plasma ionised calcium or the ratio of ionised calcium to total calcium and total bilirubin concentrations. These results suggest that the metabolic control of plasma ionised calcium in preterm infants is different from that in adults.

Association of mineral composition of neonatal intravenous feeding solutions and metabolic bone disease of prematurity.

To assess the effects of increasing the mineral content of parenteral nutrition solutions on the biochemical and radiological indicators of metabolic bone disease of prematurity 27 neonates who required parenteral nutrition were sequentially allocated to receive either a standard solution (group 1) or one with an increased mineral content (group 2). The 13 patients in group 1 received 0.68 mmol/kg/day of calcium and 0.61 mmol/kg/day of phosphorus, and the 14 in group 2 received 1.25 and 1.20 mmol/kg/day, respectively. The two groups did not differ significantly in the severity of their illness measured by birth weight, gestational age, duration of parenteral nutrition or ventilation, or the amount of supplementary oxygen required. In patients in group 2 the median plasma phosphate concentration was higher, the plasma alkaline phosphatase activity was lower, and there was less radiological evidence of rickets. There were no complications caused by excess calcium and phosphorus, and the rate of growth was similar in both groups. We conclude that an increased mineral content in parenteral nutrition solutions reduces the severity of metabolic bone disease in sick infants who require this form of nutrition.

The sick very low birthweight infant fed by parenteral nutrition: studies of nitrogen and energy.

Nine ventilator-dependent intravenously-fed very low birthweight infants with a mean birthweight of 938 (range 760-1100)g and mean gestation of 27 (range 25-29) weeks were studied provided they continued to receive more than 85 per cent of their nutritional needs intravenously. Metabolic balance studies of nitrogen over 72h were undertaken between 2 and 45d postnatal age. The average number of balances performed on each infant was three. The balances were performed at a mean postconceptional age of 5, 15, 25 and 37d. The data were compared to postconceptional age-matched fetal values and to published data from well enterally-fed infants at equivalent postnatal ages and matched for postconceptional age. There was a steady increase in length, weight and head circumference throughout the study period. The mean (range) nitrogen retention was 340 (229-415) mg/kg/d and was similar to intrauterine accretion after 200d postconceptional age, and comparable to nitrogen retention rates seen in well and enterally-fed premature infants. We conclude that parenteral nutrition can sustain growth and support nitrogen retention in the small preterm infant requiring intensive care.

Calcium and phosphorus metabolism in the premature infant.

During the last trimester of pregnancy, there is a sixfold increase in fetal calcium and phosphorus accumulation. Unsupplemented human breast milk may not provide sufficient calcium and phosphorus for the rapidly growing preterm infant to match the accumulation that should have taken place in utero and to permit normal bone mineralization. Rickets of prematurity may present clinically between the 6th and 12th postnatal week. The clinical diagnosis may be confirmed using simple biochemical tests. Inadequate mineral substrate intake, particularly of phosphorus, is the most common cause, although a delay in the maturation of the renal enzyme, 1-alpha hydroxylase, with low plasma concentrations of 1,25-dihydroxyvitamin D, may also occur. The biochemical response to treatment can be determined by documenting a fall in plasma alkaline phosphatase activity and a rise in plasma phosphate concentration and urinary phosphate excretion.

A new alkaline phosphatase isoenzyme abnormality.

We report on a new alkaline phosphatase isoenzyme abnormality occurring as an incidental finding in a male infant aged 4 months. Isoenzyme electrophoresis on cellulose acetate showed a prominent, diffuse alkaline phosphatase staining band in the alpha 1-globulin position together with a second band in the alpha 2/beta region and minor 'trailing' in the intermediate alpha 2 region. Normal liver and bone alkaline phosphatase were absent and intestinal phosphatase was not detected. On acrylamide gel electrophoresis a marked origin band was detectable suggesting the presence of high molecular weight enzyme. In addition, a series of compact bands in the alpha 2/beta position was present cathodal to the usual liver and bone isoenzymes. Total alkaline phosphatase activity was marginally elevated and was heat labile, L-phenylalanine resistant and partially L-homoarginine and L-leucine sensitive.

Subdural intravenous fat collection: an unusual complication of central intravenous feeding in the neonate.

We report on a very low birth weight preterm infant who developed a subdural collection of infusion lipid while receiving total parenteral nutrition. A possible mechanism is outlined.

Twin very low birth weight infants: a study of nutritional and hormonal status.

Nonidentical twin male infants (twin 1,950 g birth weight, twin 2,970 g) had their nutritional and hormone status studied for up to 59 days. Both infants received parenteral nutrition up to 32 days postnatally; enteral feeding was then established in twin 1; in twin 2 parenteral feeding was recommenced on day 35, for the remainder of the study. Serial 72-hr metabolic balances were performed in both infants at 4, 32, 45, and 56 days postnatally. Insulin-like growth factor I (IGF-I) and growth hormone were assayed on day 2 of each balance. During the course of the study growth was similar in each infant. Overall mean daily energy intakes were 90 kcal/kg/day and 84 kcal/kg/day and percentage nitrogen retention was 62% and 55% in twin 1 and twin 2, respectively. No differences were observed between the two infants in IGF-I or growth hormone. Despite low energy intakes incremental weights were within an acceptable range for both infants.

Plasma amino acid profiles in preterm infants receiving Vamin 9 glucose or Vamin infant.

Amino acid profiles were measured in 29 low-birth-weight infants receiving either Vamin 9 glucose (n = 18, group A) or Vamin Infant (n = 11, group B) as the amino acid source in parenteral nutrition; intake was otherwise identical. Infants were sampled when receiving 430 mgN/kg per day (3.2 g/kg per day amino acids) and 90 non-protein kcal/kg per day. There was no difference between groups in birth weight, gestational or postnatal age. The percentage N retention was similar in both (68 and 60%, groups A and B respectively). Phenylalanine and tyrosine levels were higher in those who received Vamin 9 glucose but 55% of infants given Vamin Infant had tyrosine levels below the lower limit of the target range. Cysteine levels were low in both groups. Further modification of the amino acid composition of parenteral solutions for the newborn is necessary. If sufficient non-protein energy can be provided the risk of abnormally high amino acid levels is reduced.

Growth velocity and plasma alkaline phosphatase activity in the preterm infant.

The relationship between growth and plasma alkaline phosphatase activity differs in the preterm infant when compared with older children and adolescents. 18 preterm infants were studied over the first 12 postnatal weeks; growth velocity and plasma alkaline phosphatase activity were measured serially. Plasma calcium, inorganic phosphate, the vitamin D metabolites and parathyroid hormone were assayed at a median age of 3 and 6 weeks. There was an overall significant negative correlation between growth and plasma alkaline phosphatase activity (r = -0.37; P less than 0.005); this was more marked in a group where the plasma alkaline phosphatase activity exceeded the preterm reference range. Plasma 1,25-dihydroxycholecalciferol and inorganic phosphate were lower in this group at 3 weeks but not at 6 weeks when compared with infants where plasma alkaline phosphatase activity did not exceed the reference range. There was no difference in caloric intake between the groups. In the preterm infant biochemical rickets is common and unlike older children and adolescents an increase in plasma alkaline phosphatase activity correlates with decreased rather than increased growth.

Mosaic trisomy 16 in a live newborn infant.

Trisomy 16 is thought to be incompatible with fetal survival. A boy with mosaic trisomy 16 who lived for 11 weeks is reported. Chromosome analysis was carried out on skin fibroblasts grown during life and confirmed on samples taken at necropsy. We believe that this is the first report of mosaic trisomy 16 that has been confirmed by cytogenetic banding.

Acute endocarditis following pneumococcal meningitis.

Acute mitral valve endocarditis, presenting as a new murmur and haematuria, complicated pneumococcal meningitis in a 20-month-old child with a normal heart. Awareness of this rare complication of pneumococcaemia and its early diagnosis, using cross-sectional echocardiography, improves the clinical outcome of a condition associated with a high mortality.

Hypophosphataemic rickets in the preterm infant; hypocalcaemia after calcium and phosphorus supplementation.

A preterm infant with hypophosphataemic rickets became hypocalcaemic when given milk specially formulated for preterm infants that contained increased phosphorus and calcium. The rickets resolved spontaneously. Routine calcium and phosphorus supplementation for preterm neonates should be investigated further.