Effects of various forms of surfactant protein C on tidal volume in ventilated immature newborn rabbits

various forms of surfactant protein C on tidal volume in ventilated immature newborn rabbits. J Appl Physiol 94: 1519–1526, 2003. First published October 25, 2002; 10.1152/ japplphysiol.00059.2001.—Surfactant protein (SP)-C is char-acterized by -helix structure and palmitoyl groups attached to two cysteine residues. We examined the function of palmi-toylation and dimerization in promotion of tidal volume in immature newborn rabbits. Reconstituted surfactants were made from a mixture of synthetic phospholipids and porcine SP-B (basic mixture) by adding various forms of SP-Cs: normal SP-C isolated from porcine lungs and monomeric or dimeric forms of SP-C. These latter two were isolated from patients with pulmonary alveolar proteinosis and were less palmitoylated. Animals were ventilated at an inspiratory pressure of 25 cmH2O. Median tidal volumes were 2 ml/k