The objective of this study was to examine the relationship between malondialdehyde-thiobarbituric acid (MDA-TBA) levels, as a measure of lipid peroxidation, in very low birthweight (VLBW) infants and outcome measures. A prospective observational longitudinal study was carried out in two level III neonatal units in the South Island of New Zealand measuring MDA-TBA levels in 61 VLBW infants in 1993. MDA-TBA levels were measured in (i) maternal plasma within 48 h of parturition, (ii) cord plasma, and (iii) infants' plasma at 2, 7, 14 and 28 days of age and correlated with antenatal and postnatal factors. Elevated levels of plasma MDA-TBA at 7 days were associated with adverse respiratory and ophthalmological outcome in the VLBW infants. Elevated MDA-TBA levels were measured at sample times close to the time of death in the infants who died. These results substantiate previously reported preliminary observations and support the hypothesis that oxidative injury, particularly within the first 7 days of life, is associated with the development of the long-term complications of the pre-term infant. MDA-TBA levels appear to be a useful measure to continue to explore the role of free radical mediated disease in the VLBW infant.

Endogenous plasma AA continues to decrease over the first 5 days in hospital and the extent is related to the severity of acute pancreatitis. Presented to a meeting of the Australasian Surgical Research Society, Auckland, New Zealand, August 1995 and published in abstract form as Aust N Z J Surg 1996; 66: 243

P Pr ro ot te ei in na as se e--a an nt ti ip pr ro ot te ei in na as se e b ba al la an nc ce e i in n t tr ra ac ch he ea al l a as sp pi ir ra at te es s f fr ro om m n ne eo on na at te es s Activities of neutrophil elastase and its inhibitors were measured in tracheal aspirates from 17 infants, 10 of whom subsequently developed bronchopulmonary dysplasia.All aspirates contained immunologically detectable α 1 -proteinase inhibitor (α 1 -PI), but their inhibitory capacity against neutrophil elastase ranged from being undetectable to being in excess of the amount of α 1 -PI detected immunologically. When the α 1 -PI was removed from each of the aspirates, using a specific antibody, from 0-50% of the original activity remained, indicating the presence of another elastase inhibitor. Its properties were consistent with it being the low molecular mass, secretory leucoproteinase inhibitor (SLPI), also known as bronchial antileucoproteinase. The α 1 -PI was from 0-100% active. Most of the inactive inhibitor was shown by western blotting to be complexed with elastase, with a small amount of cleaved material. There was no evidence of major oxidative inactivation. Free elastase was detected in only three of the aspirates; these had little or no detectable elastase inhibitory capacity, and most of their α 1 -PI was complexed. Elastase load, comprising the sum of free and complexed elastase, correlated closely with myeloperoxidase activity, a recognized marker of inflammatory activity. Active SLPI levels showed a positive correlation with gestational age (r=0.66).We conclude that most neutrophil elastase in the upper airways of ventilated infants is complexed. This indicates that lung secretions of most infants contain adequate inhibitory activity of α 1 -PI and probably secretory leucoproteinase inhibitor.

Parenteral lipids are susceptible to light‐induced peroxidation, particularly under phototherapy. Ascorbic acid is protective. The aim of this study was to investigate whether dark delivery tubing and/or coadministration of multivitamin preparations could prevent peroxidation of Intralipid without undue vitamin loss. In experiments carried out on the benchtop, lipid peroxidation occurred in ambient light and was more extensive under phototherapy. Dark tubing decreased peroxide formation, but only by about 65%. In simulated clinical conditions in which solutions were pumped through standard clear or dark minibore plastic tubing, Intralipid accumulated lipid peroxides as measured by the FOX assay (280 μM) or as triglyceride hydroperoxides (52 μM). Multivitamin preparations (MVIP or Soluvit/Vitlipid) inhibited peroxide formation almost completely, and were fully protective when used with dark tubing. There was loss of riboflavin (65% from Soluvit and 35% from MVIP) in clear tubing but this was decreased to 18% and 11%, respectively, in dark tubing. Ascorbate loss was 20% (MVIP) and 50% (Soluvit) and only slightly less in dark tubing. Ascorbate loss was also seen in the absence of Intralipid and is due to riboflavin‐induced photo‐oxidation. Conclusion: Multivitamin preparations protect Intralipid against light‐induced formation of lipid hydroperoxides, and administering multivitamins with Intralipid via dark delivery tubing provides a practical way of preventing peroxidation of the lipid while limiting vitamin loss. This procedure should be considered for routine use as well as with phototherapy.

No abstract