ABSTRACT
Bovine pulmonary surfactant was obtained by endotracheal lavage of lungs from newly slaughtered calves followed by differential centrifugation.Lipid extracts of bovine surfactant contained 86.1?2.1% "of phospholipids (X?SD) , 1.8?1.1%of protein and smaller amounts of cholesterol, fatty acids, glycerides and carbohydrate. Phosphatidylcholine(83.4?5.6%)accounted for most of the phospholipids, of which disaturated phosphatidylcholine was 76.0? 4.7% .The physicochemical properties of bovine surfactant were measured with a modified Wilhelmy film balance made by the authors.The minimum surface tension was 2.4?1.5mN/m, stability index was 1.78?0.15, surface compresibility at 10mN/m was 0.022?0.004 m/mN, and surface concentration of phospholipids at 10mN/m was 1.112?0.283 nmol/cm2. The surfactant spread rapidly and could be quickly absorbed to the surface of the water.The results show that the bovine pulmonary surfactant we isolated is able to meet the criteria for investigations of surfactant replacement therapy.