Fig. 1.

Western blots of mature and pro-SP-B in the unfractionated (total), large aggregate (pellet; LA), and small aggregate (supernatant; SA) surfactant fractions from simultaneously obtained trachéal aspirate (TA) and bronchoalveolar lavage (BAL) specimens from 1 older child. Mature and pro-SP-B peptides were similar in both the BAL and TA: mature SP-B was present in both SA fraction and the surface active LA fraction, while pro-SP-B was present in the SA fraction only. In Infasurf, only mature SP-B was detected, and only in the LA fraction.