Figure 6.

Surfactant function. Three pools of large aggregate fractions (three mice/pool) of surfactant from SP-C (+/+) and SP-C (−/−) mice were used to assess equilibrium surface tension, and minimal surface tension was achieved on a captive-bubble surfactometer. The equilibrium surface tension and minimum surface tension were measured by using a standard bubble size (A). Surface tension measurements with a reduced bubble volume (B) demonstrated bubble-surface film instability with surfactant preparation from SP-C (−/−) mice whereas bubble stability was maintained with surfactant preparations from SP-C (+/+) mice.