A case of hyperzincemia with functional zinc depletion: a new disorder?

We report the case of an 1l-y-old boy with a plasma Zn concentration greater than 200 micromol/L, but with symptoms consistent with Zn deficiency. He has had hepatosplenomegaly, rashes, stunted growth (<3rd centile), anemia, and impaired immune function since infancy. He also has vasculitis and osteoporosis. A plasma Zn-binding protein has been separated and characterized by a combination of size exclusion and ion exchange chromatography and electrophoretic studies and by immunologic methods. Antibodies to the partially purified protein have been raised in rabbits. Size exclusion chromatography shows that Zn is bound to a protein with a mass 110000-300000 kD. Electrophoretic and mass spectrometry studies suggest that the protein may be composed of several subunits. One component of the isolated protein reacts with antiserum to alpha2-macroglobulin; immunoprecipitation studies confirm that the protein is not alpha2-macroglobulin or a histidine-rich glycoprotein. Kinetic studies of zinc metabolism in the patient and his mother with stable Zn isotopes show the presence of increased exchangeable Zn, with a rapid flux from plasma to a stable pool. Liver and muscle Zn and Cu concentrations are raised, but with no abnormal liver histology. Immunoreactive metallothionein in the liver is increased. We suggest that this boy may suffer from a previously unrecognized inborn error of Zn metabolism causing symptomatic zinc deficiency.

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.

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.

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.

Introduction of intravenous lipid administration on the first day of life in the very low birth weight neonate.

OBJECTIVE: To investigate lipid tolerance in sick, ventilator-dependent, very low birth weight infants from the first day of life and the effects of early introduction of intravenously administered lipid (IVL) on glucose homeostasis. METHOD: Twenty-nine infants in the neonatal intensive care unit with birth weight less than 1500 gm received isocaloric, isonitrogenous parenteral feedings from day 1 with either IVL, 1 gm/kg from day 1 to 3 gm/kg from day 4 (group I; n = 16), or IVL added only from day 8 (group II; n = 13). Possible adverse clinical effects were monitored. Blood metabolites, nonesterified fatty acids, serum triglycerides, and insulin levels were determined daily. Arterial blood gases were measured and changes in partial pressures of oxygen and of carbon dioxide in arterial blood were compared between the two groups. RESULTS: Early lipid infusion did not appear to have deleterious effects on blood gas tensions or to increase respiratory morbidity. The incidence of other adverse clinical effects that may be associated with IVL was not increased by earlier introduction of lipid. Serum lipid values were comparable to those of preterm infants receiving IVL at a later postnatal age. Blood glucose concentrations were higher in group II (mean, 7.50 (SEM 0.43) mmol/L) than in group I (mean, 6.01 (SEM 0.28) mmol/L; p less than 0.05). There was no evidence of increased gluconeogenesis in infants in group I and no correlation between blood glucose concentrations and serum nonesterified fatty acid concentrations. CONCLUSION: When given infusion rates not exceeding 0.15 gm/kg/hr, sick, very low birth weight infants can tolerate IVL with stepwise dose increases from the first day of life without an increased incidence of possible adverse effects.

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.

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.

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.

Calcium and phosphorus solubility in neonatal intravenous feeding solutions.

The limited solubility of calcium and phosphorus in standard parenteral nutrition formulations has restricted the ability to provide sufficient minerals to preterm infants to prevent substrate deficient metabolic bone disease. We determined the solubility limits of calcium and phosphorus in a total of 160 formulations under carefully controlled conditions. By increasing the concentrations of dextrose, amino acids, and by using Addiphos instead of 8.7% dipotassium hydrogen phosphate as the phosphorus source, higher concentrations of both calcium and phosphorus were held in solution. This should permit the delivery of increased concentrations of these minerals at rates which approximate fetal accretion.

Acid-base state of the preterm infant and the formulation of intravenous feeding solutions.

An acidic intravenous source of phosphorus (Addiphos) was compared with dipotassium hydrogen phosphate in 25 preterm infants to study acid-base state. Eight infants were given either Addiphos or dipotassium hydrogen phosphate alternately for 48 hour periods and similar amounts of calcium and phosphorus were delivered. There were no significant differences in calcium and phosphorus intake, calcium and phosphate plasma concentrations, or acid-base state between study periods on the two solutions. Seventeen infants were given the two solutions alternately for 72 hour periods; Addiphos was used to increase the amounts of calcium and phosphorus being delivered. Calcium and phosphorus intake was decreased on dipotassium hydrogen phosphate, but Addiphos significantly increased calcium and phosphorus intake and plasma calcium and phosphate concentrations. It also lowered the pH of the urine and raised the titratable acidity. Acid-base state, however, was not significantly different. It is therefore possible to increase intake of calcium and phosphorus in preterm infants without causing a significant metabolic acidosis.

Tape measure to aid prescription in paediatric resuscitation.

A tape measure, based on 50th centile weight for height and designed to permit easy drug dosage calculation, endotracheal tube size and DC cardioversion current dosages in childrens' emergencies, was tested for reliability by medical and nursing staff with varying paediatric experience. We found that the tape measure gave a reproducible estimate of weight and suggest that its use would facilitate decision making by inexperienced medical and nursing staff in paediatric resuscitation when there is no time to weigh the child.

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.

Early parenteral feeding of amino acids.

Serial 24 hour balance studies of nitrogen and energy were carried out over 10 days in two groups of ventilator dependent preterm infants, of comparable weight and gestational age. In one group (n = 10) a parenteral amino acid source (Vamin 9) was started within 24 hours of birth, and in the other group (n = 11) it was not started until 72 hours. The feeding protocol was otherwise identical. The nitrogen intake (286 compared with 21 mg/kg/day), energy intake (188 compared with 151 kJ), and nitrogen retention (120 compared with -133 mg/kg/day), were all significantly higher during the first three days of life in the group in which the amino acid solution was started early. There were no differences by 7-10 days. The early introduction of amino acids improves the early nutritional state of sick preterm infants.