studies investigate calf lung buy NVP BGJ398 surfactant extract, which has documented high activity in reversing states of surfactant deficiency in mammalian lungs, and is the substance of the clinical surfactant InfasurfH. RESULTS Circular dichroism and FTIR spectroscopy on Mini-B in TFE or DEPN-8 Synthetic Lung Surfactant for conformation. Instead, Mini-B in the presence of DEPN-8 was studied using FTIR spectroscopy, which is not subject to lightscattering artifacts. FTIR was also used to assess DEPN-8 in the absence of Mini-B. Multilayers of DEPN-8 exhibited a strong C-O-C absorption band between wavenumbers of 10041157 cm21, consistent with behavior previously shown for phospholipids with ether-linked alkyl chains. DEPN-8 multilayers also had an absorbance peak at wavenumbers of,1220 to 1260 cm21 indicative of the asymmetric stretching frequencies of the polar headgroup, as well as contributions from CH2- scissoring absorption in the spectral region of 1462 to 1473 cm21. Dominant 14500812 absorptions for the alkyl chains that included antisymmetric and symmetric stretching bands around 2917 and 2850 cm21 were also found. DEPN-8 multilayers did not exhibit absorption in the region of 1710 1740 cm21, which is characteristically associated with the C = O stretch of normal ester linkages in glycerophospholipids. FTIR spectra for Mini-B in TFE and in DEPN-8 were similar, with substantial overlapping regions but some small variations. The FTIR spectrum of Mini-B in TFE had a major amide I band centered at 1655 cm21, indicating a predominant ahelical conformation. 14985929 FTIR spectral deconvolution analysis indicated mean secondary structure percentages for Mini-B in TFE of 37.1% a-helix, 33.5% turn/bend, 10.6% b-sheet, and 17.8% disordered. This structural distribution is similar to that obtained from the CD spectrum of Mini-B in TFE, with the largest difference being a higher percentage of turn/bend structures in the FTIR analysis compared to the CD analysis. Deconvolution of the FTIR spectrum of Mini-B in DEPN-8 indicated a further increase in the proportion of turn/bend elements relative to the FTIR spectrum of Mini-B in TFE . These FTIR results indicate direct interactions between Mini-B and DEPN-8 at the molecular level. a low dissociation rate constant . DEPN-8 had a slightly higher kon rate for Mini-B compared to DPPC, but the diether lipid also had a higher mean koff rate. Values for the mean equilibrium dissociation constant were low and similar for DEPN-8 and DPPC, showing that both lipids had substantial 
molecular affinity for the chip-linked Mini-B monolayer. Resistance of synthetic surfactants containing DEPN-8+1.5% by weight Mini-B to degradation by phospholipase A2 The structural resistance of DEPN-8 to degradation by phospholipases is a potential advantage for this compound as a constituent in novel exogenous surfactants for use in inflammatory lung injuries where lytic enzymes of this kind are released. Mixtures of DEPN8+1.5% Mini-B were incubated in vitro with 0.1 Units of PLA2, and completely resisted degradation from this enzyme based on thin layer chromatographic analysis. In contrast, CLSE is significantly degraded by PLA2, with a substantial decrease in its content of phosphatidylcholine and a substantial increase in lysophosphatidylcholine as reported in our prior work. Adsorption and pulsating bubble surface activity of synthetic lung surfactants containing DEPN-8+1.5% by weight Mini-B peptide Combining Mini-B with DEPN-8 in a binary mixture si