Pulmonary artery occlusion. 3. Biochemical alterations.

Abstract
Five days after unilateral pulmonary artery ligation biopsies were taken from normal-appearing and hemorrhagic areas of ligated lungs and from opposite, nonligated, control lungs. Histologic sections were made and alveolar bubble stability, phospholipid content, phospholipid distribution, fatty acid composition, and rates of enzymatic biosynthesis of surface-active material were estimated. The results indicate that following ligation areas of normal-appearing lung are unchanged biochemically from opposite nonligated lung but that hemorrhagic atelectatic areas of ligated lung show decreased phospholipid content, decreased dipalmitoyl phosphatidyl choline and alterations in esterified fatty acid composition and enzyme activity. Biochemical studies correlate well with histologic and physiologic data and emphasize that focal rather than general changes occur in lung following pulmonary artery ligation.