Surface activity of saline extracts from inflated and degassed normal lungs

Abstract

Normal rabbit lungs have been extracted in aerated and in vitro degassed states to clarify the effect of atelectasis upon the surface activity of saline lung extracts. Three extraction techniques, chopping, mincing, and pestle-homogenization, were compared. All extraction methods give highly active extracts using aerated lung samples, but extracts from airless lungs prepared by chopping or mincing invariably showed higher minimum surface tensions, lower stability indices, and took more time to reach minimum tension than did extracts of the same lungs when aerated. Differences could be due to decreased area of saline-alveolar contact during extraction, as it was noted that increasing the weight of the lung sample or dividing the lung more finely (i.e., pestle homogenization) increased extract activity. If saline extracts of atelectatic lung are studied, qualitative statements about presence of surfactant should take into account weight of lung tissue and technique of extraction. lung surface tension; atelectasis; pulmonary surfactant material; rabbit lung surface activity Submitted on September 11, 1963