Surface Activity Of Surfactant Research Articles

ChemInform Abstract: Synthesis and Surface Activity of Surfactants Containing Fluorocarbon Hydrophobes.

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Interaction of transferrin saturated with iron with lung surfactant in respiratory failure.

Proteins that decrease the surface activity of surfactant accumulate in epithelial lining fluid in respiratory failure. The aim of this study was to isolate a surfactant inhibitor from the airways of rabbits in acute respiratory failure induced by bronchoalveolar lavage (BAL). This inhibitor was identified as being transferrin (TF). Unlike serum TF, TF recovered in respiratory failure was saturated with iron (Fe(3+)-TF). Fe(3+)-TF decreased the surface activity of normal surfactant in vitro, whereas iron-free TF had no effect. In the presence of H2O2 and a reducing agent, Fe(+3)-TF inactivated the surfactant complex: the surface absorption rate was decreased, immunoreactive surfactant protein A was decreased, and malondialdehyde was formed. The acute effects of Fe(3+)-TF and iron-free TF applied to the airways were studied in animal models. In respiratory failure induced by BAL, Fe(3+)-TF deteriorated respiratory failure, whereas iron-free TF had no effect. In respiratory failure induced by hyperoxia for 48 h, administration of iron-free TF ameliorated the respiratory failure and improved the surface activity in BAL. We propose that Fe(3+)-TF accumulating in epithelial lining fluid during lung damage contributes to surfactant inhibition and promotes the formation of free radicals that inactivate the surfactant system.

In Vitro Inactivation of Pulmonary Surfactant Replacement Preparations by Serum Albumin

Inactivation of the surface activity of pulmonary surfactant by serum proteins is an important part of neonatal respiratory distress syndrome. The ability of serum proteins to diminish the surface activity of surfactant preparations used to treat respiratory distress syndrome has not been fully described. The sensitivity of clinically useful pulmonary replacement preparations beractant (Survanta) and colfosceril palmitate, cetyl alcohol, and tyloxapol (Exosurf) to albumin inactivation was examined in vitro by the Wilhelmy plate technique. At a final lipid concentration of 0.1 mg/mL and in the absence of albumin, both Survanta and Exosurf exhibited equilibrium surface tensions in the range of 35 dynes/cm. In the presence of albumin, range of 35 dynes/cm. In the presence of albumin, the surface tension of Survanta was markedly higher. Maximal response of Survanta to albumin was observed at about 1 mg/mL protein concentration. When the lipid concentration was raised to 0.3 mg/mL, the presence of albumin had little effect. With Exosurf, the presence of albumin resulted in only minor elevations of surface tension, even at an albumin concentration 10-fold greater than that used in the experiments with Survanta. These results indicate that at lipid concentrations of 0.1 mg/mL and less, the surface activity of the bovine purified lung surfactant Survanta is more sensitive to the presence of albumin than is the synthetic preparation Exosurf.

Uptake of antioxidants in surfactant liposomes by cultured alveolar type II cells is enhanced by SP-A

Antioxidant delivery may be targeted toward the alveolar epithelium by encapsulating superoxide dismutase (SOD) and catalase in liposomes made from pulmonary surfactant. We studied whether antioxidant-surfactant liposomes increase cellular antioxidant activity in alveolar type II cells and whether this effect is influenced by the presence of surfactant protein A (SP-A). Cu,Zn SOD and catalase were encapsulated in liposomes made from synthetic phospholipids with or without 5% SP-A or from natural cow surfactant. Alveolar type II cells from adult rats were preincubated for 20 h, and liposome mixtures were added for 24 h, followed by measurement of cellular SOD and catalase activities (U/mg DNA). Antioxidant-surfactant liposomes increased alveolar type II cell antioxidant activity sharply. Uptake of SOD/catalase from liposomes with synthetic phospholipids and SP-A was twice that from liposomes without SP-A and did not further improve in the presence of SP-B and -C. Encapsulation of antioxidants diminished the surface activity of the surfactant liposomes, but this feature was absent in the presence of SP-A. These data suggest that: 1) antioxidant-surfactant liposomes augment alveolar type II cell antioxidant activity, 2) liposomal uptake is facilitated by the presence of SP-A, and 3) inhibition of surface activity of surfactant by encapsulated antioxidants can be reversed by SP-A.

Synthesis and surface activity of nonionic surfactants containing fluorocarbon hydrophobes

AbstractNonionic surfactants having polydisperse polyoxyethylene chains and highly fluorinated hydrophobes were synthesized via a complex reaction route and their adsorption at water/air interfaces studied. They exhibit high surface activity and decrease both effectively and efficiently the surface tension of their aqueous solutions. The effect of the length of the polyoxyethylene chain upon surfactant surface activity is relatively low. Lower values of surface tension, below 30 mN m−1, are obtained for surfactants having a low degree of ethoxylation. Surfactants having two terminal highly fluorinated hydrophobes are less surface active than analogues with one terminal hydrophobe.

Enterobacter agglomerans lipopolysaccharide-induced changes in pulmonary surfactant as a factor in the pathogenesis of byssinosis.

Lipopolysaccharide (LPS) from Enterobacter agglomerans and pulmonary surfactant mixtures were centrifuged in discontinuous sucrose gradients to determine whether LPS bound to surfactant and examined in a Langmuir trough with a Wilhelmy balance to determine whether LPS altered the surface activity of surfactant. The LPS was found to bind to the surfactant and altered its surface tension properties. The binding of LPS to surfactant in the lung may change the physiological properties of surfactant and be a possible mechanism for the pathogenesis of byssinosis.

Divalent cation and hydrogen ion effects on the structure and surface activity of pulmonary surfactant

The structure and surface activity of the extracellular fraction of pulmonary surfactant known as tubular myelin are Ca2+ dependent. Previous studies have demonstrated surfactant-specific proteins with monomeric molecular weights of 28,000-36,000 (SP28-36) are associated with this fraction. In reassembled lipoprotein mixtures, SP28-36 promotes the Ca2+-induced aggregation and surface activity of surfactant lipids, but the detailed interactions between Ca2+, SP28-36, and surfactant lipids have not been established. In this study, we investigated the effect of various cations on the aggregation of surfactant lipid liposomes in the presence of SP28-36. SP28-36 reduced the threshold ion concentration for liposome aggregation from greater than 10 to 0.5 mM for Ca2+, Ba2+, and Sr2+ but not Mg2+ or Mn2+. The liposome aggregation was reversed by ethylenediaminetetraacetic acid and not associated with leakage of carboxyfluorescein. SP28-36 promoted similar liposome aggregation at pH less than 5 in the absence of divalent cations. Surfactant lipids adsorbed slowly to an air-fluid interface in all ionic conditions unless SP28-36 was present. Both Ca2+ and H+ induced rapid lipid adsorption in the presence of SP28-36. The surface activity of native surfactant had a similar ion dependence. Electron micrographs of native surfactant showed typical tubular myelin structures at pH 7.4 only in the presence of Ca2+. At pH 4.4 in the absence of Ca2+, similar but not identical structures were seen. In the reconstituted system, SP28-36 in the presence of Ca2+ induced the formation of larger multilayered structures including parallel bilayers and small areas of squares and triangles with dimensions similar to structures found in the native material.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of inorganic electrolyte concentration on anionic-cationic adsorption films Part 1. Decylpyridinium chloride + sodium octylsulphonate + sodium chloride

The effect of NaCl on simultaneous adsorption of decylpyridinium chloride (R10PyCl) and sodium octylsulphonate (R8SO3Na) on the free surface of their aqueous solutions has been examined. The surface excess of each component was determined on the basis of a suitable form of the Gibbs adsorption equation. The ionic strength effect on the adsorption of particular components of mixtures, as well as on the composition of anionic-cationic films adsorbed from equimolar solutions, is small. This is due to little difference in surface activity of surfactants investigated.

Surface activity of surfactant in experimental compression atelectasis

Surface surfactant activity was studied at different time periods of compression atelectasis, induced by hydrothorax in 35 guinea pigs. The animals were slaughtered 30 and 60 minutes or 3, 12 and 24 hours after hydrothorax. It has been demonstrated that experimental compression atelectasis is accompanied by surface activity lowering, associated with disorders in surfactant secretion into the alveolar lumen. The qualitative composition of surfactant phospholipids remains unchanged, which may play an essential role in the recovery of lung tissue aeration.

Glycolipid accumulation in bronchoalveolar space in adult respiratory distress syndrome.

Surfactant lipids in the alveolar space are believed to play an important role in normal respiratory function. Although the surface-active phospholipids have been extensively studied, the possible role of glycolipids in the surfactant remains to be explored. We have studied the glycolipid composition of cell-free bronchoalveolar lavage from healthy subjects and from adult patients with respiratory distress syndrome. Glycolipids were barely detectable in bronchoalveolar lavage from healthy subjects. However, in adult respiratory distress syndrome, the amount of glycolipid relative to phospholipid was increased by more than twenty times. These lipids, identified as lactosylceramide (galactose-glucose-ceramide) and paragloboside (galactose-N-acetylglucosamine-galactose-glucose-ceramide), may prove to be sensitive markers of lung injury. Since the glycolipids decreased the surface activity of surfactant in vitro, their potential role in the pathogenesis of adult respiratory distress syndrome should be considered.

Mixed adsorbed film of dodecylammonium chloride with decylammonium chloride at water/air interface

The surface tension of the aqueous solution containing dodecylammonium chloride and decylammonium chloride has been measured as a function of total concentration at 298.15°K under atmospheric pressure. It has been observed that the surface tension decreases with increasing the composition of dodecylammonium chloride at a fixed total concentration and the surface tension vs concentration curve has a distinct break point. By applying the thermodynamic relations developed, the surface densities of surfactants have been evaluated numerically. Examining the relation of the composition in the bulk phase to the one in the adsorbed film at constant surface tension, the difference in the surface activities of surfactants has been found to be pronounced at high surface tension. It has been proved that the break point corresponds to the phase transformation of the adsorbed film from a gaseous to an expanded state. It has been shown that the phase transition is expressed by a two-dimensional phase diagram.

Effect of oxygen and hypergravitation on alveolar surfactant

The effect of prolonged exposure (up to 66 hours) to pure oxygen breathing and to short (5-minute) oxygen breathing combined with acceleration (+5Gz) on the surface tension and surface potential of the alveolar washout of the albino rat lungs was determined. Both experimental conditions produced atelectasis and a decrease of the surfactant surface activity. Possible mechanisms of shifts of the surfactant activity under hyperoxia only, and hyperoxia with accelerations are discussed.

Effect of general anesthetics on surface activity of the lung alveolar surfactant

The surface properties of the lung surfactant were studied with a modified Wilhelmy's apparatus after general anesthesia. Halothane and, to a lesser degree, pentobarbital, were shown to inhibit the surface activity of the surfactant. This phenomenon was observed only after prolonged (4–6 h) general anesthesia.

Radiotracer Studies on Adsorption of Surface Active Substance at Aqueous Surface. III. The Effects of Salt on the Adsorption of Sodium Dodecylsulfate

Abstract The adsorbed amounts were measured on the surface of aqueous solutions containing tritiated sodium dodecylsulfate (TSDS) and varying amounts of NaCl by the direct radiotracer method. The surface tensions were also measured for the same solutions by the drop-volume method. The Gibbs adsorption isotherm, derived without assuming the adsorption of the chloride ion, was applied, and the amounts of adsorption were calculated for both dodecylsulfate and chloride ions. The observed amounts of dodecylsulfate adsorption were confirmed to be in good agreement with those calculated, and the calculated amounts of chloride adsorption turned out to be nearly zero or slightly negative, which is usually theoretically assumed because of the ionic repulsion due to the adsorbed dodecylsulfate. Further, the adsorption of the dodecylsulfate ion attained a constant and saturate value beyond a certain concentration (SAC) below the critical micelle concentration (CMC). The logarithms of SAC were found to vary linearly with the logarithms of CMC for the range of salt concentration studied. The value of SAC being in a close relation with the surface phenomena is considered to be another measure of the surface activity of surfactants.

Influence of surface-active substances on depolarization kinetics

The previously described “depolarization kinetics” is being used for studying the surface activity of surfactants. The surface activity of a few pH Depolarization kinetics has been used for studying the surface activity of a few surfactants. The rate of depolarization is enhanced (time for first an

Selective adsorption studies at the air-solution interface of aqueous solutions of surfactant mixtures by radio tracer techniques

Competitive adsorption at the air-solution interface of aqueous solutions of surfactant mixture has been studied, using surfactants which were labeled with C 14 and S 35, respectively. Relative adsorptivity was obtained from the ratio of radioactivity ratios of C 14 and S 35 in adsorbed layer and in bulk phase. Relative adsorptivity of sodium hexadecanoate 1-C 14 to sodium dodecyl sulfate S 35 was about 12 and that of sodium dodecyl sulfate S 35 to sodium dodecanoate 1-C 14 was about 5.6. Adsorptivity increases about 2.9 per one addition of methylene group. The reciprocal of the CMC is proportional to the surface activity of surfactant.