The role of a lysosome fraction from rabbit type II cells in surfactant dipalmitoylphosphatidylcholine (DPPC) catabolism was investigated in vivo using radiolabeled DPPC and dihexadecylphosphatidylcholine (1, 2-dihexadecyl-sn-glycero-3-phosphocholine; DEPC), a phospholipase A(1)- and A(2)-resistant analog of DPPC. Freshly isolated type II cells were gently disrupted by shearing, and lysosomes w...

Liposomes or model membranes are widely used basic systems which mimic biological membranes. In this study, the physical interaction between dipalmitoyl phosphatidylcholine (DPPC) and lipid-lowering drug acipimox was investigated using Differential Scanning Calorimetry (DSC) technique depending on different concentrations temperature. The changes in phase transition temperature, enthalpy curve ...

The interactions between phospholipid monolayers and dimethylsulfoxide (DMSO) molecules were investigated by vibrational sum frequency generation (VSFG) spectroscopy in a Langmuir trough system. Both the head and the tail groups of dipalmitoylphosphatidylcholine (DPPC) as well as DMSO were probed to provide a comprehensive understanding of the interactions between DPPC and DMSO molecules. A con...

Tacrolimus (FK506) is a hydrophobic immunosuppressive agent that rapidly penetrates the plasmatic membrane and inhibits the signal transduction cascade of T lymphocytes. The objective of this study was the characterization of liposomal FK506 with surfactant-like phospholipids to be administered intratracheally after lung transplantation or in inflammatory lung diseases. We evaluated the optimal...

Interactions between amphiphilic block copolymers and lipids are of medical interest for applications such as drug delivery and the restoration of damaged cell membranes. A series of monodisperse poly(ethylene oxide)-poly(butylene oxide) (EOBO) block copolymers were obtained with two ratios of hydrophilic/hydrophobic block lengths. We have explored the surface activity of EOBO at a clean interf...

Surface pressure (pi)-, surface potential (deltaV)-, and dipole moment (mu(perpendicular))-area (A) isotherms and morphological behavior were examined for monolayers of a newly designed 18-mer amphiphilic alpha-helical peptide (Hel 13-5), DPPC, and DPPC/egg-PC (1:1) and their combinations by the Wilhelmy method, ionizing electrode method, fluorescence microscopy (FM), and atomic force microscop...

Fluorescence and infrared spectroscopy and cholesterol oxidase activity were employed to investigate the effect of phosphatidylcholine (PC) acyl chain length mismatch on the lateral organizations of lipids in liquid-ordered dipalmitoyl-PC/dilauroyl-PC/cholesterol (DPPC/DLPC/CHOL) bilayers. Plots of steady-state fluorescence emission anisotropy of diphenylhexatriene (DPH) labeled PC (DPH-PC) emb...

We investigated the phase separation of dioleoylphosphatidylserine (DOPS) and dipalmitoylphosphatidylcholine (DPPC) in giant unilamellar vesicles a hypotonic solution using fluorescence confocal laser scanning microscopy. Although charged lipid membranes is generally suppressed by electrostatic repulsion between headgroups, osmotic stress can promote formation domains. Interestingly, we observe...

We studied the effects of four soluble surfactants on DPPC monolayers to elucidate the action of these membrane perturbants. The presence of nonionic N-9 and amphoteric C31G strongly affected the pure DPPC isotherm, while anionic SDS and cationic DTAB had little effect. The impact of surfactant on DPPC domain shape in the liquid condensed-liquid expanded coexistence region showed the opposite r...

A thermodynamic study of monolayer mixing behavior was performed using binary lipid mixtures of DPPC + DOPG (7:1 mol:mol) as well as a mixture containing the phosphocholine acyl chain perdeuterated analog of DPPC, DPPC-d62 (i.e. 7:1 mol:mol DPPC-d62 + DOPG). An analysis was performed on these isotherms that calculated the Helmholtz excess free energy of mixing to determine potential thermodynam...