Dynamic surface activity of a fully synthetic phospholipase-resistant lipid/peptide lung surfactant.

Background: This study examines the surface activity and resistance to phospholipase degradation of a fully-synthetic lung surfactant containing a novel diether phosphonolipid (DEPN-8) plus a 34 amino acid peptide (Mini-B) related to native surfactant protein (SP)-B. Activity studies used adsorption, pulsating bubble, and captive bubble methods to assess a range of surface behaviors, supplemented by molecular studies using Fourier transform infrared (FTIR) spectroscopy, circular dichroism (CD), and plasmon resonance. Calf lung surfactant extract (CLSE) was used as a positive control.

Activity and inhibition resistance of a phospholipase-resistant synthetic surfactant in rat lungs.

This study investigates the activity and inhibition resistance in excised rat lungs of a novel synthetic surfactant containing the phospholipase-resistant diether phosphonolipid DEPN-8 plus 1.5% bovine surfactant protein (SP)-B/C compared to calf lung surfactant extract (CLSE). DEPN-8 + 1.

Surface properties of sulfur- and ether-linked phosphonolipids with and without purified hydrophobic lung surfactant proteins.

Two novel C16:0 sulfur-linked phosphonolipids (S-lipid and SO(2)-lipid) and two ether-linked phosphonolipids (C16:0 DEPN-8 and C16:1 UnDEPN-8) were studied for surface behavior alone and in mixtures with purified bovine lung surfactant proteins (SP)-B and/or SP-C. Synthetic C16:0 phosphonolipids all had improved adsorption and film respreading compared to dipalmitoyl phosphatidylcholine, and SO(2)-lipid and DEPN-8 reached maximum surface pressures of 72mN/m (minimum surface tensions of <1mN/m) in compressed films on the Wilhelmy balance (23 degrees C). Dispersions of DEPN-8 (0.

Inhibition of surfactant activity by Pneumocystis carinii organisms and components in vitro.

This study examines the direct inhibitory effects of Pneumocystis carinii (Pc) organisms and chemical components on the surface activity and composition of whole calf lung surfactant (WLS) and calf lung surfactant extract (CLSE) in vitro. Incubation of WLS suspensions with intact Pc organisms (10(7) per milligram of surfactant phospholipid) did not significantly alter total phospholipid levels or surfactant protein A content. Incubation with intact Pc organisms also did not impair dynamic surface tension lowering in suspensions of WLS or centrifuged large surfactant aggregates on a bubble surfactometer (37 degrees C, 20 cycles/min, 0.

Synthesis and interfacial behavior of sulfur-containing analogs of lung surfactant dipalmitoyl phosphatidylcholine.

Synthesis methods and initial surface property characterizations are reported for two sulfur-containing phosphonolipids related structurally to dipalmitoyl phosphatidylcholine (DPPC), the major lung surfactant glycerophospholipid. Sulfur linkages in these compounds affect molecular interactions relative to ester linkages, and are structurally resistant to cleavage by phospholipases. The SO2-linked analog synthesized here had increased adsorption and improved film respreading compared to DPPC, while reaching very low surface tensions (1 N/m) in cycled interfacial films on both the Wilhelmy balance and the pulsating bubble surfactometer.