Serum copper and ceruloplasmin in preterm infants: prospective study.

The postnatal time courses in preterm infants (30.0 weeks mean gestational age) of serum copper and ceruloplasmin (Cp) are described and compared. Serum copper was measured by nonflame atomic absorption spectrophotometry and serum Cp was measured by both immunodiffusion (Cpi) and enzyme assay (Cpe). With the exception of Cpe between 7 and 11 weeks of age, correlations among the three laboratory parameters were excellent. Following an early rise in all values, a plateau was seen in copper and Cpi between 5 and 11 weeks; Cpe showed a discordant fall at 7 to 11 weeks of age. After 11 weeks a secondary and definitive rise in all values was seen. Examination of individual time courses indicates the existence of a subgroup of infants with falling values between 5 and 11 weeks of age. Preterm infants had significantly higher serum copper (0.53 +/- 0.05 micrograms/ml) at a mean postnatal age of 10 weeks (39-41 weeks postconception) than did full-term infants (0.44 +/- 0.04 microns/ml) of similar postconceptional age. Low serum copper values were correlated with parenteral nutrition deficient in copper, with increased growth rates, and with twin pregnancies. It is concluded that extrauterine life in preterm infants is associated with precocious rises in serum copper and Cp values. The subgroup of infants with falling values may represent subclinically copper-deficient infants. This subgroup may bias the results of grouped data downwards. A role for nutritional factors in the delayed postnatal rise of serum copper and Cp values in preterm infants cannot be excluded on the basis of current knowledge.

Urinary polyamines in preterm infants.

Polyamines were determined in urine of 22 preterm infants (mean 30.0 weeks gestation) from birth to 22 weeks of age, and in full-term infants in the first week of life. A significant decline in urine putrescine and spermidine levels occurred with increased postnatal age in preterm infants. At expected term preterm infants had significantly higher levels of polyamines in urine than full-term infants at the same postconceptional age. No constant correlations between weight or linear growth velocity and urinary polyamine excretion could be established in this group of infants. Altered urine polyamine values were detected in two clinical situations: hyperbilirubinemia was associated with increased urine spermidine (and with increased spermidine/putrescine ratio), and liver disease was associated with increased levels of both putrescine and spermidine in urine.