Surfactant activity and mobilization in minced saline extracts of neonatal brain, heart, kidney, liver, and lung

Abstract

Minced saline tissue extracts yield minimum values higher than airspace washings, attributed to different proportions of saturated fatty acids and phosphatidylcholine, with typical hysteresis in both. Saline minced extracts from newborn autopsy tissues (Kimray Greenfield surfactometer) follow the formation of lung lesions; 16 newborns up to 90 hrs had a progressive but counter intuitive decline in lung minimum values, suggesting enhanced synthesis without therapy or recruitment of surfactant [Regression equation: minimum (dynes/cm) = −0.1936 (survival hrs) + 23.7040]. No difference was seen by gestational time (22–40 wks), as shown by Esterly (Am.J.Clin.Path. 46:649, 1966), a finding against surfactant deficiency due to prematurity per se. Lesser declines in the minimum was found in extracts of myocardium (43.1% of lung), kidney (17.8%), liver (16.5%), while the minimum worsened in extracts from cerebrum (+7.0%), the largest pool of phospholipids of the five tissues. This sequence suggests possible mobilization of surface active lipids during the first four days after birth, despite respiratory or other disorders. Twenty stillborns had similar results by gestational age; mean minimums for stillborn lung and liver were not significantly different from mean newborn values (lung, t = 0.392, p = 0.696; liver, t = 1.019, p = 0.315). Thus, newborn surfactant dynamics are systemic.Support: The Rhad Trust