Experiment 1: Surfactant recovery in lung lavage and surface activity of LA. A: surfactant pool size of TS, LA and SA sub-fractions measured by phosphorous assay. Data are expressed as amount of phospholipids/kg body weight. Within each sub-fraction, *p < 0.05 vs the No Treatment condition. B: minimum surface tension of pooled LA samples during different dynamic compression-expansion cycles. #p < 0.05 versus cycle 1 and 2 within each experimental condition. Values are expressed as mean ± SEM.; n = 6 per group.