A B S T R A C T Pulmonary effluent samples were obtained from 26 preterm or term infants throughout the period of endotracheal intubation. Infants with respiratory distress syndrome, infants with this disorder developing bronchopulmonary dysplasia, and intubated infants without lung disease were compared daily in terms of lung effluent cellularity, albumin, elastase activity, a1-proteinase content and activity, and elastase inhibitory capacity. The elastase activity was determined to be neutrophilic in origin. Polyacrylamide gel electrophoresis of pulmonary effluents from two infants with respiratory distress syndrome and exposed to FiO2 5 0.6 up to 6 d revealed cleavage of oal-proteinase inhibitor to a 47,000-mol weight fragment suggestive of oxidation. Pulmonary effluent neutrophils, macrophages, and elastase activity were increased by day 3 of life in infants with respiratory distress syndrome eventually developing bronchopulmonary dysplasia. Elastase inhibitory capacity and a1-proteinase inhibitor activity were reduced in infants developing chronic lung disease. Bronchopulmonary dysplasia developed in infants with enhanced inflammatory response, but with less or inhibited antiprotease activity.

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A B S T R A C T Autopsy findings suggest that lung surfactant is damaged in the adult respiratory distress syndrome. In the present study 225 bronchoalveolar lavage specimens (78 from 36 patients, 1-78 yr old with respiratory failure, 135 from another 128 patients with other respiratory disease, and 12 from healthy controls) were assayed for the lung profile [lecithin/ sphingomyelin (L/S) ratio, saturated lecithin, phosphatidylinositol, and phosphatidylglycerol]. Bronchoalveolar lavage fluid was further analyzed for phospholipids and for phosphatidic acid phosphohydrolase, phospholipase A2, and phosphatidylinositol phosphodiesterase activities. A lipid-protein complex was isolated and analyzed for surface activity, and plasma was measured for myoinositol.There were only small differences seen in the recovery of total phospholipid between respiratory failure patients and normal controls. However, in respiratory failure, phospholipids in bronchoalveolar lavage were qualitatively different from those recovered either from normal controls or from patients with other lung disease: the L/S ratio, phosphatidylglycerol, and disaturated lecithin were low, whereas sphingomyelin and phosphatidylserine were prominent. These abnormalities were present early in respiratory failure A preliminary report of this work was presented at the

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