Necrotizing enterocolitis after intravitreal bevacizumab in an infant with Incontinentia Pigmenti - a case report.

BACKGROUND: Incontinentia Pigmenti is a rare disease affecting multiple organs. Fifty of patients show affection of the eye with retinopathy and possible amaurosis being the worst outcome. Treatment has commonly been panretinal laser coagulation but intravitreal application of bevacizumab as VEGF-inhibitor has shown to effectively suppress retinal neovascularization. CASE PRESENTATION: A six-week-old female infant with Incontinentia Pigmenti developed a foudroyant necrotizing enterocolitis shortly after intravitreal injection of bevazicumab due to a retinopathy with impending tractional detachment of the left eye. Since the onset of abdominal symptoms occurred immediately after the intravitreal application, a link between the two events seemed likely. Sequential analyses of the VEGF serum concentrations showed a massive suppression of endogenous VEGF with only a very slow recovery over weeks. Such a severe systemic adverse event has not been reported after intravitreal treatment with bevacizumab in an infant. CONCLUSION: This case report shows a relevant systemic uptake of bevacizumab after intravitreal application as suppressed VEGF levels show. There seems to be a connection between suppressed VEGF levels and the onset of necrotizing enterocolitis. Therefore, treatment with bevacizumab should be carefully considered and further research is needed to assess this drug's safety profile.

[Lung Function in Childhood and Adolescence: Influence of Prematurity and Bronchopulmonary Dysplasia]. / Lungenfunktion in Kindheit und Adoleszentenalter: Einfluss von Frühgeburtlichkeit und bronchopulmonaler Dysplasie.

INTRODUCTION: The introduction of prenatal steroids, surfactant replacement therapy and gentle ventilation modes has reduced short term respiratory morbidity and increased survival of very preterm infants. However, there is some evidence that prenatal factors, the extend of prematurity and bronchopulmonary dysplasia (BPD) may affect pulmonary function in childhood and adolescence. METHODS: We have performed a comprehensive review on the outcome of pulmonary function after premature birth before 32 weeks of gestation in the era of surfactant replacement therapy and tried to evaluate the influence of chorioamnionitis, intrauterine growth retardation (IUGR), maternal metabolic syndrome, prematurity and BPD on long term pulmonary function. RESULTS: Some children and adolescents born very preterm may experience significant airflow reduction. The bronchial obstruction in these patients is not entirely reversible by inhalative ß2-mimetics. The degree of pulmonary function impairment is partly correlated with the degree of BPD. Abnormalities in pulmonary diffusion capacity may occur after extreme prematurity, but also in patients with moderate and severe BPD. IUGR may have a negative impact on later pulmonary function in very children. There is insufficient data to assess the preterm impact of chorioamnionitis or maternal metabolic syndrome on later lung function. CONCLUSION: Infants born before 32 weeks of gestational age in the surfactant era still carry an increased risk to suffer an impaired pulmonary function in childhood and adolescence, particularly if they survived with BPD. Long term pulmonary care for these patients should take place in specialized centers.

[Intrauterine inflammation and its sequelae: does chorioamnionitis really matter for outcome of very low birth weight infants?]. / Intrauterine Inflammation und ihre Folgen: Spielt Chorioamnionitis eine Rolle für Organschäden bei sehr kleinen Frühgeborenen?

Infections in utero and chorioamnionitis are major risk factors for spontaneous, very early premature birth. Thus chorioamnionitis contributes significantly to prematurity-associated morbidity and mortality. Evidence for a gestation-independent effect of chorioamnionitis on the outcome of very low birth weight infants is much more difficult to obtain as most of the studies addressing this issue lack a normal "control group", as prematurity is mostly associated with some kind of prenatal pathology with a potential influence on neonatal outcome. Moreover, major advances in perinatal and neonatal care for this high-risk group have mitigated the impact of chorioamnionitis on morbidity and mortality of very low birth weight infants. Histological chorioamnionitis is associated with a lower incidence and severity of respiratory distress syndrome. However, short-term maturational effects on the lung are associated with a higher susceptibility for postnatal noxious events, such as mechanical ventilation, thus contributing to the risk of bronchopulmonary dysplasia. Data regarding the importance of chorioamnionitis for brain damage of the very premature infant are inconsistent although meta-analyses have shown an increased risk of cystic periventricular leukomalacia and cerebral palsy after exposure to inflammation in utero. Very recent epidemiological studies suggest a role of chorioamnionitis in the aetiology and pathogenesis of retinopathy of prematurity.

Nosocomial sepsis in neonatal intensive care: inevitable or preventable?

Very low birth weight (VLBW) infants are at high risk to develop a neonatal nosocomial sepsis. The incidence of neonatal nosocomial, late-onset sepsis (LOS) is about 20-30%, but a rate of up to 43% has been reported among neonates with a birth weight of 400-750 g. Preventive and treatment strategies for neonatal sepsis in VLBW infants are aiming to enhance the infant's host defence mechanisms. Neonatal immunodeficiencies include quantitative and qualitative deficits in phagocytes, complement components, and immunoglobulins. A considerable number of immune strategies has been investigated in carefully designed multicentre trials. These include exchange transfusion, neutrophil transfusion, hematopoietic growth factors such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF), intravenous immunoglobulins (IVIG), and others. Since none of these interventions was able to reduce the mortality rate of immature preterm infants, the current evidence does not support the use of any of the immune strategies for prevention or treatment of neonatal sepsis. Decreasing the burden of intensive care and following strict hygiene programs at NICUs may be the most promising current strategies to minimise nosocomial infection.

[Significance of nitric oxide inhalation (NO) in preterm infants< 34 weeks of gestation]. / Stellenwert der Inhalation von Stickstoffmonoxid (NO) bei Frühgeborenen<34 Gestationswochen.

In 2001, NO was approved as a therapeutic agent in Europe for the treatment of persistent pulmonary hypertension in late preterm infants >34 weeks of gestational age and term newborns. Recent observational studies suggest, that preterm infants <34 weeks of gestation with acute hypoxic lung failure could benefit from inhaled NO (iNO) by improved oxygenation. To date, 21 randomised-controlled trials have enrolled 3 336 preterm infants <34 weeks of gestation for iNO treatment. Overall, iNO treatment does not reduce the rate of bronchopulmonary dysplasia (BPD) or death compared to controls. In addition, iNO treatment of preterm infants with hypoxic respiratory failure or increased risk of BPD does not affect the combined incidence of death and BPD. However, early prophylactic use of iNO in preterm infants with respiratory distress seems to improve survival without BPD or severe cerebral damage. Current data of long term neurological outcome of iNO-treated preterm infants do not seem to justify iNO administration. Outside of well designed clinical trials iNO-treatment of preterm infants can currently not be recommended.

[Leukemoid reaction in extremely immature preterm infants]. / Leukämoide Reaktion bei extrem unreifen Frühgeborenen.

Extremely immature preterm infants rarely present with a leukocytosis exceeding 30,000/microL. The pathogenetic sequence leading to leukemoid reactions in non-malignant diseases remains to be elucidated. Potential triggers for leukemoid reactions in premature infants include prenatal corticosteroids, chorioamnionitis and funisitis or systemic infection. In the two-year period from 2006 to 2007 all infants with a gestational age of less than 26 weeks were screened for leukocytosis. Among our cases, one preterm infant presented with a leukocyte count of 229,300/microL at the age of 48 hours, lasting throughout the first three weeks of life. Impairment of microcirculation and resulting organ dysfunction were not observed. Thus, invasive therapeutic procedures, which are routinely initiated in hyperleukocytosis in accompanying malignant diseases, may not have the same significance in extremely immature preterm infants and should be executed in these patients on an individual basis and with extreme caution.

Nonventilatory strategies for prevention and treatment of bronchopulmonary dysplasia--what is the evidence?

This review briefly summarizes the evidence for a number of mainly drug-related strategies to prevent or treat bronchopulmonary dysplasia (BPD). Oxygen supplementation is frequently used in neonatal units and oxygen toxicity plays an important role in the pathogenesis of BPD. However, current evidence for an optimal oxygen saturation for extremely premature infants is scarce. This gap in knowledge will hopefully be closed by a number of ongoing or prospective trials addressing this issue. The role of inhalational nitric oxide in the prevention of BPD is still unclear despite existing data from a number of large randomized trials. Early administration of caffeine seems to confer a benefit with regard to BPD. Prophylactic or early application of surfactant may also be beneficial. High intramuscular doses of vitamin A slightly reduce the incidence of the disease. There is currently no evidence supporting other nutritional interventions to prevent BPD. Anti-inflammatory drugs, like alpha(1)-proteinase inhibitor, pentoxifylline and azithromycin, and antioxidants, like N-acetylcysteine and superoxide dismutase, have not been proven effective yet. Diuretics can ameliorate lung function, but there is no evidence supporting their long-term use. Ureaplasma urealyticum colonization of airways is associated with an increased risk of BPD. However, there is no proof for an effect of erythromycin on BPD. The potential roles for therapies like bombesin-like peptide-blocking antibodies or Clara cell 10-kDa protein have yet to be defined.

All-trans retinoic acid and intra-amniotic endotoxin-mediated effects on fetal sheep lung.

All-trans retinoic acid (RA) is a potent modulator of lung development. Chorioamnionitis, which is frequently associated with preterm birth, causes fetal lung inflammation and improves lung function but also results in alveolar simplification and microvascular injury. Endotoxin-mediated chorioamnionitis reduces RA concentration in the fetal lung to 16% of control values. We hypothesized that administration of RA to the fetus before induction of chorioamnionitis would preserve septation of the distal airspaces. Time-mated ewes with singletons were assigned to receive a fetal intramuscular treatment with 20,000 IU of RA in olive oil (or olive oil only) 3 hr prior to intra-amniotic injection of endotoxin (20 mg, E. coli 055:B5) or saline, at 124-day gestational age and 7 days after the fetal treatment. The right cranial lung lobe was processed for morphometric analysis. RA treatment did not affect chorioamnionitis-induced fetal and systemic inflammation or interleukin-8 concentrations in lung tissue. RA administration alone did not alter lung structure. Relative to control lungs (5 +/- 3 mL/kg), lung volume increased similarly with endotoxin (22 +/- 4 mL/kg) or RA plus endotoxin (20 +/- 3 mL/kg; P < 0.05). Alveolar wall thickness was 4.2 +/- 0.3 mum after endotoxin-induced chorioamnionitis, 6.0 +/- 0.4 mum in controls (P < 0.05 versus endotoxin) and 5.5 +/- 0.2 mum after RA and endotoxin (P < 0.05 versus control, n.s. versus endotoxin). The ratio of airspace versus tissue was 4.6 +/- 0.3 in endotoxin-induced chorioamnionitis, 2.1 +/- 0.3 in controls and 4.1 +/- 0.5 after RA and endotoxin. We conclude that fetal treatment with RA did not prevent inflammation-induced alveolar simplification.

Pulmonary inflammation and bronchopulmonary dysplasia.

Various pre- and postnatal risk factors, which act additively or synergistically induce an injurious inflammatory response in the airways and the pulmonary interstitium of preterm infants with bronchopulmonary dysplasia. This inflammatory response is characterized by an accumulation of neutrophils and macrophages as well as an arsenal of proinflammatory mediators that affect the endothelium and alveolar-capillary integrity. Besides proinflammatory cytokines and toxic oxygen radicals, lipid mediators as well as potent proteases may be responsible for acute lung injury. There is increasing evidence that an imbalance between pro- and anti-inflammatory factors, which should protect the alveoli and lung tissue, are key features in the pathogenesis of bronchopulmonary dysplasia. In addition, a subnormal generation of growth factors may affect alveolarization and vascular development in preterm infants with bronchopulmonary dysplasia. In this condensed review article, the current concepts on the possible role of inflammation in the evolution of bronchopulmonary dysplasia will be summarized.

Cerebral mass in a 13-year-old girl following long-term sojourn in the Tropics.

Cysticercosis of the central nervous system is the main cause of late-onset epilepsy in tropical countries. The case of a 13-year-old German girl with a generalized seizure following long-term sojourns in the Tropics is reported. Cranial imaging showed two cerebral lesions with central calcifications. Serological, molecular and cultural examination of cerebrospinal fluid and blood was negative for various parasites, fungi and bacteria including mycobacteria. Histopathological examination after neurosurgical resection revealed calcareous bodies pathognomonic for platyhelminths, in particular tapeworms. Taken together, the radiological and histopathological findings indicate infection with cysticerci, the larvae of Taenia solium.

[Pharmacological prophylaxis and treatment of bronchopulmonary dysplasia]. / Medikamentöse Prophylaxe und Therapie der bronchopulmonalen Dysplasie.

Treatment with prenatal steroids, prophylactic or early therapeutic surfactant substitution, application of early nasal CPAP, minimizing of mechanical ventilation, early treatment of PDA and avoiding nosocomial infections are the main measures to prevent the development of bronchopulmonary dysplasia (BPD) in high-risk pre-term neonates. Beside these strategies, several pharmacologic interventions to prevent or to treat BPD have been investigated. So far, clear evidence for effective prevention has only been demonstrated for the administration of vitamin A and vaccinations. The administration of oxygen is the only effective treatment modality. Unfortunately, the upper and lower limits for the dosage of oxygen are still not clear. In patients with established BPD, a transient therapeutic effect is observed following treatment with systemic diuretics, inhaled steroids, and inhaled bronchodilators. However, treatment with these drugs has no documented long-term effect on the course of the disease. Systemic steroids only play a role as rescue treatment in life-threatening situations. Treatment with inhaled or systemic pulmonary vasodilatative may have a place in the treatment of pulmonary hypertension in severely affected infants. However, long-term experience in this treatment modality is still lacking.

Apoptosis and proliferation in lungs of ventilated and oxygen-treated preterm infants.

Apoptosis and proliferation and the effect of exogenous surfactant on these processes were investigated in the lungs of mechanically ventilated/oxygen-treated preterm infants with respiratory distress syndrome and stillborn foetuses. Apoptotic and proliferation indices were determined in lung tissue sections from 27 ventilated/oxygen-treated preterm infants and 29 stillborn foetuses. The effect of exogenous surfactant on apoptosis and proliferation was studied in 16 ventilated preterm infants; 11 untreated infants served as control. Apoptotic and proliferating cells were identified by double labelling combining terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate nick end-labelling or Ki-67 with cell marker proteins. Pathways to cell death were explored by immunolabelling of cleaved caspases-3, -8 and -9. In the lungs of ventilated/oxygen-treated preterm infants, the numbers of apoptotic and proliferating cells increased significantly compared to the respective numbers in the lungs of stillborn foetuses. Apoptosis was detected in alveolar epithelial cells, whereas epithelial, endothelial and smooth muscle cells proliferated. Surfactant treatment reduced apoptosis induced by ventilation/oxygen-treatment; however, the decrease was not significant. Caspases-8 and -9 do not contribute to ventilation-induced apoptosis, whereas caspase-3 is involved. In conclusion, ventilation/oxygen-treatment induces epithelial cell apoptosis and proliferation of epithelial, endothelial and smooth muscle cells in the lungs of preterm infants.

The current role of colony-stimulating factors in prevention and treatment of neonatal sepsis.

OBJECTIVES: To review the role of colony-stimulating factors as adjuncts in the therapy of neonatal sepsis. DATA SUMMARY: Data provided by animal experiments and in vitro experiments in human neonates demonstrate the inability of newborn infants to significantly upregulate colony-stimulating factor expression during infectious challenge. In a few clinical trials, exogenous administration of colony-stimulating factors has been associated with reduced neonatal morbidity and mortality. However, reviewing the existing data on colony-stimulating factor administration in neonates, evidence for efficacy and benefit of these adjuncts in treating neonatal sepsis still appears to be poor. CONCLUSION: Further randomized, placebo-controlled clinical trials, particularly for the subgroups of premature infants or infants with neutropenia, are urgently warranted before routine application of these cytokines can be recommended.

Chorioamnionitis and inflammation of the fetal lung.

OBJECTIVE: Fetal intrauterine exposure to proinflammatory cytokines present in amniotic fluid has been associated with an increased risk of chronic lung disease. However, the impact of histologically confirmed chorioamnionitis on the fetal lung has not yet been elucidated. We therefore investigated cellular immune response, cell proliferation, and messenger ribonucleic acid cytokine expression in fetal pulmonary tissue in the presence or absence of chorioamnionitis. STUDY DESIGN: Serial tissue sections were obtained from 27 fetuses at the time of autopsy. Three mothers had received antibiotics for treatment of clinical chorioamnionitis before abortion. Immunohistochemical staining of lung tissue comprised lineage-specific markers (CD68(+), CD3(+), neutrophil elastase). Positively stained cells were evaluated with a graticule, and cells per 5 mm(2) were counted. We undertook in situ hybridization to assess the expression of interleukin 8 messenger ribonucleic acid in the fetal lung. RESULTS: Seven of 27 fetuses had been exposed to chorioamnionitis. Fetal lungs showed a marked increase in the presence of histologically confirmed chorioamnionitis in densities of CD68(+) macrophages (68 vs 9.5 cells/5 mm(2), median group vs control group; P =.02) and lymphocytes (7 vs 2.5 cells/5 mm(2), median chorioamnionitis vs control group; P =.05) and a similar but lesser increase in neutrophil density (16 vs 4 cells/5 mm(2); difference not significant). Interleukin 8 messenger ribonucleic acid was expressed in 4 of 6 tissue specimens investigated in the chorioamnionitis group. Exposure to chorioamnionitis resulted in interleukin 8 messenger ribonucleic acid expression 7-fold higher than in the nonchorioamnionitis group; however, this difference did not achieve statistical significance. CONCLUSION: Chorioamnionitis was associated with an intrauterine inflammatory response of the fetal lung characterized by a severe infiltration of macrophages, neutrophils, and lymphocytes and also by an increased expression of interleukin 8 messenger ribonucleic acid.

Double-outlet right ventricle and overriding tricuspid valve reflect disturbances of looping, myocardialization, endocardial cushion differentiation, and apoptosis in TGF-beta(2)-knockout mice.

BACKGROUND: Transforming growth factor-beta(2) (TGF-beta(2)) is a member of a family of growth factors with the potential to modify multiple processes. Mice deficient in the TGF-beta(2) gene die around birth and show a variety of defects of different organs, including the heart. METHODS AND RESULTS: We studied the hearts of TGF-beta(2)-null mouse embryos from 11.5 to 18.5 days of gestation to analyze the types of defects and determine which processes of cardiac morphogenesis are affected by the absence of TGF-beta(2). Analysis of serial sections revealed malformations of the outflow tract (typically a double-outlet right ventricle) in 87.5%. There was 1 case of common arterial trunk. Abnormal thickening of the semilunar valves was seen in 4.2%. Associated malformations of the atrioventricular (AV) canal were found in 62.5% and were composed of perimembranous inlet ventricular septal defects (37.5%), AV valve thickening (33.3%), overriding tricuspid valve (25.0%), and complete AV septal defects (4.2%). Anomalies of the aorta and its branches were seen in 33.3%. Immunohistochemical staining showed failure of myocardialization of the mesenchyme of the atrial septum and the ventricular outflow tract as well as deficient valve differentiation. Morphometry documented this to be associated with absence of the normal decrease of total endocardial cushion volume in the older stages. Apoptosis in TGF-beta(2)-knockout mice was increased, although regional distribution was normal. CONCLUSIONS: TGF-beta(2)-knockout mice exhibited characteristic cardiovascular anomalies comparable to malformations seen in the human population.

New insights into the pathogenesis of pulmonary inflammation in preterm infants.

Chronic lung disease (CLD) and bronchopulmonary dysplasia are associated with a significant inflammatory response of the airways and the interstitium of the lungs. Besides inflammatory cells, various cytokines, lipid mediators, proteolytic enzymes and toxic oxygen radicals may play an essential role in the pathogenesis of this disease. Intrauterine exposure to chorioamnionitis or proinflammatory cytokines has been shown to induce a pulmonary and systemic inflammatory response in the fetus. In this subgroup, antenatal infection may prime the lung such that minimally injurious postnatal events provoke an excessive inflammatory response in the airways and the pulmonary tissue. Inflammation and lung injury most certainly affect normal alveolization and pulmonary vascular development in preterm infants with CLD.

S-100 after correction of congenital heart defects in neonates: is it a reliable marker for cerebral damage?

BACKGROUND: Newborns undergoing cardiac operation may acquire some extent of neuronal damage. An early diagnosis is especially hard regarding neonates. In the past years, S-100 has been widely discussed as a marker revealing perioperative damage to the brain. METHODS: Sequential blood samples from 33 neonates undergoing repair of congenital heart disease were taken perioperatively. Samples of 12 healthy neonates were taken at birth as a control group. The newborns were divided into four groups: cyanotic and acyanotic disease operated on in deep hypothermic circulatory arrest, operation without deep hypothermic cardiac arrest, and operation without extracorporeal circulation. RESULTS: Even in healthy neonates, serum S-100 levels were at 10-fold values compared with adults. On admission, S-100 values in the operative groups were similar. During extracorporeal circulation, levels rose to a certain degree. Cyanotic newborns operated on in deep hypothermic cardiac arrest had significantly higher S-100 levels compared with acyanotic newborns also operated on in deep hypothermic cardiac arrest (p < 0.001). Two newborns who experienced seizures postoperatively had the highest absolute S-100 levels. One child with a poor neurologic outcome but no seizures did not have different values when compared with her group. CONCLUSIONS: In this study, S-100 seemed to be a possible marker for a certain degree of neurologic deficit after cardiac operation in neonates, especially regarding postoperative seizures. The missing peaks of this protein in one newborn with poor neurologic outcome show that it is not possible to exclude damage to the brain with normal postoperative values. These results suggest that the mechanism of cerebral damage and S-100 release into the blood in neonates with a developing central nervous system and blood-brain barrier is not fully understood.

Decreased mRNA expression of G-CSF receptor in cord blood neutrophils of term newborns: regulation of expression by G-CSF and TNF-alpha.

Granulocyte colony-stimulating factor (G-CSF) promotes neutrophil production and enhances neutrophil function. The effects of G-CSF are mediated by binding to its receptor. Since neutrophils are an essential part of the neonatal host defense system, we studied G-CSF receptor expression in neonatal neutrophils. We determined protein and mRNA expression of G-CSF receptor in freshly isolated neutrophils from cord blood of healthy term newborns (n = 16) and of adults (n = 6) as well as the in vitro effect of supplemented recombinant human G-CSF (rhG-CSF) and tumor necrosis factor-alpha (TNF-alpha) on G-CSF receptor expression of neutrophils. Expression of G-CSF receptor on the surface of neutrophils of cord blood was significantly lower compared to adults (61 +/- 6 vs. 89 +/- 2%). G-CSF receptor mRNA transcripts of neutrophils from newborns compared to adults was lower, too (77 +/- 14 vs. 152 +/- 33%). Neutrophils isolated from cord blood showed a decrease of G-CSF receptor expression within 24 h of culture. Moreover, we were able to show that supplemented rhG-CSF is necessary for maintenance of G-CSF receptor expression. TNF-alpha, however, down-regulated G-CSF receptor expression. We conclude that low protein and mRNA expression of G-CSF receptor in neutrophils of neonates compared to adults may adversely affect granulopoiesis and neutrophil functions by decreased responsiveness to G-CSF. Furthermore, G-CSF receptor expression on neutrophils was modified not only by G-CSF itself, but also by TNF-alpha.

[Superoxide dismutase and catalase activity in tracheobronchial secretions after surfactant treatment of newborn infants with respiratory distress syndrome]. / Aktivität von Superoxiddismutase und Katalase im Tracheobronchialsekret nach Surfactantbehandlung Frühgeborener mit Atemnotsyndrom.

Oxygen toxicity and mechanical ventilation are main factors in the development of chronic lung disease in preterm infants. We examined two antioxidant enzymes, superoxide dismutase (SOD) and catalase, in tracheal fluid of preterm infants with severe respiratory distress syndrome (RDS) treated with surfactant. SOD and catalase catalyse the transformation of oxygen radicals and hydrogen peroxide to less toxic metabolites. 31 preterm infants were randomised to either single or multiple dose treatment with surfactant (Curosurf). Tracheal aspirates were obtained during routine tracheal suctioning and the two enzymes were measured during the first week of life. 11 of 31 preterm babies (35%) did not show any SOD-activity in tracheal fluid. Four out of the eleven preterm infants developed bronchopulmonary dysplasia. Patients receiving multiple dose treatment had significantly higher SOD-activity (> 10 micrograms/mg albumin, p < 0.01) than patients with single dose treatment. Only 2 of 31 preterm babies (6%) lacked catalase activity in tracheal aspirate. 94% had catalase activity between 1 and 12 micrograms/mg albumin. We conclude that, the majority of preterm infants with severe RDS do not have protective superoxide dismutase activity in tracheal fluid. Following multiple dose surfactant replacement significantly higher SOD activity was observed as compared to single dose therapy.