A Direct Test of the 'Squeeze-Out' Hypothesis of Lung Surfactant Function. External Reflection FT-IR at the Air/Wave Interface
| العنوان: | A Direct Test of the 'Squeeze-Out' Hypothesis of Lung Surfactant Function. External Reflection FT-IR at the Air/Wave Interface |
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| المؤلفون: | Belinda Pastrana-Rios, Richard Mendelsohn, Carol R. Flach, Alan J. Mautone, Joseph W. Brauner |
| المصدر: | Biochemistry. 33:5121-5127 |
| بيانات النشر: | American Chemical Society (ACS), 1994. |
| سنة النشر: | 1994 |
| مصطلحات موضوعية: | Degree of unsaturation, Chromatography, 1,2-Dipalmitoylphosphatidylcholine, Chemistry, Air, Lipid Bilayers, Molecular Conformation, Analytical chemistry, Water, Phosphatidylglycerols, Pulmonary Surfactants, Surface pressure, Models, Biological, Biochemistry, Surface tension, Pulmonary surfactant, Deuterium, Spectroscopy, Fourier Transform Infrared, Monolayer, Animals, Fourier transform infrared spectroscopy, Spectroscopy, Lung |
| الوصف: | The current theory of pulmonary surfactant function requires that very low surface tension be achieved and maintained in the alveolar surface film during compression (expiration). To effect this condition, it has been hypothesized that the unsaturated and/or fluid components of surfactant are selectively excluded or "squeezed out" from mixed monolayers containing both saturated and unsaturated phospholipids, leaving a surface film of essentially pure 1,2-dipalmitoylphosphatidylcholine (DPPC). External reflection Fourier transform infrared (FT-IR) spectroscopy has been employed to quantitatively test this hypothesis. Mixed monolayer films of acyl chain-perdeuterated 1,2-dipalmitoylphosphatidylcholine (DPPC-d62) with 1,2-dioleoylphosphatidylglycerol (DOPG), 1-palmitoyl, 2-oleoylPG (POPG), 1,2-dipalmitoylPG (DPPG) were examined in situ at the air/water interface as a function of surface pressure. The relative intensities of CD2 (CH2) stretching vibrations of the deuterated (proteated) components permitted quantitative determination of the relative concentrations of each in the film. For 7:1 (mol:mol) mixtures of DPPC-d62/DOPG, progressive, selective squeeze out of up to about 90% of the PG component is observed over a range of surface pressures from about 51 to 68 mN/m. The extent of maximal PG squeeze out was reduced to 61% for a 7:1 (mol:mol) mixture of DPPC-d62/POPG. This phenomenon, which is at least partially reversible, appears to require relatively high rates of film compression. Squeeze out was reduced (< 20%) for 7:1 (mol:mol) mixtures of DPPC-d62/DPPG or for 7:3 mixtures of DPPC-d62/POPG. Squeeze out requires that the lipid mixture achieve surface pressures greater than about 50-60 mN/m along with unsaturation (or at least conformational disorder) in the acyl chains of the non-DPPC component.(ABSTRACT TRUNCATED AT 250 WORDS) |
| تدمد: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi00183a016 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::41139490fac8dc110fe5fcda82bf0358 https://doi.org/10.1021/bi00183a016 |
| رقم الانضمام: | edsair.doi.dedup.....41139490fac8dc110fe5fcda82bf0358 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15204995 00062960 |
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| DOI: | 10.1021/bi00183a016 |