New technique to quantify phospolipids in disordered phase in lung surfactant by electron spin resonance.

In pulmonary surfactant (PS) the coexistence of the ordered (Lo) and disordered (Ld) lipid phases would be essential for an optimal activity. Electron spin resonance (ESR) of PS labeled with 5-doxil stearic acid shows two spectral components called S and W. S/W ratio could be understood as the ratio between the probe population in Lo and in Ld.

Budesonide associated with exogenous pulmonary surfactant in a novel formulation to improve the delivery to the lung.

Lung delivery for glucocorticoids (GCs) is very low and depends on the system used. Exogenous pulmonary surfactant (EPS) is a promising tool to transporting GCs efficiently to the airways. We developed a new formulation of EPS with Budesonide (BUD) incorporated into EPS membranes (EPS-BUD) to improve lung delivery of BUD.

Determining the fluid ordered and disordered phases in a pulmonary surfactant by electron spin resonance technique.

Pulmonary surfactant main function is to reduce surface tension at alveolar interface. Two lipids phases coexist in surfactant membranes: a liquid-ordered (Lo) and a liquid-disordered (Ld) phases. This coexistence of phases would be crucial for the surfactant activity.

Boar sperm protein tyrosine phosphorylation in the presence of egg yolk soluble and low density lipoprotein fractions during cooling.

Increased protein tyrosine phosphorylation and the appearance of a phosphorylated protein of 32 kD (p32) are reported among the capacitation-like changes in cryopreserved boar sperm. Egg yolk freezing extenders are composed by two fractions: insoluble granules and soluble plasma, which contains the low density lipoproteins (LDL) proposed as responsible for the egg yolk cryoprotective action. The aim of this work was to analyze the effects of complete egg yolk and its insoluble, soluble and LDL fractions on boar sperm quality and protein tyrosine phosphorylation after the first stage of a standard cryopreservation protocol.

Developing an exogenous pulmonary surfactant-glucocorticoids association: Effect of corticoid concentration on the biophysical properties of the surfactant.

Glucocorticoids (GCs) are used to treat lung disease. GCs incorporated in an exogenous pulmonary surfactant (EPS) could be an alternative management to improve drug delivery avoiding side effects. In the development of these pharmaceutical products, it is important to know the maximum amount of GC that can be incorporated and if increasing quantities of GCs alter EPS biophysical properties.

Analysis of the structure and surfactant activity of novel formulations containing exogenous pulmonary surfactant and glucocorticoids.

Exogenous pulmonary surfactant (EPS) could be used as carrier of glucocorticoids (GCs) in therapy for respiratory diseases. We formulated novel combination drug products containing bovine EPS and one GC (10wt%): beclomethasone (Be), budesonide (Bu) or fluticasone (Flu), and studied the GCs action on the surface activity and biophysical properties of EPS. Subtype ratio was evaluated by phospholipid determination; surface tension (ST) with a pulsating bubble surfactometer and conformational changes by Electron Spin Resonance (ESR).

Effect of serum lipoproteins and cholesterol on an exogenous pulmonary surfactant. ESR analysis of structural changes and their relation with surfactant activity.

The study of structural changes in the surfactant may help to understand the mechanisms by which the surfactant is inactivated by serum. Here, we compared the in vitro effects of serum, albumin, lipoproteins (VLDL, LDL, HDL) and cholesterol on the dynamic and structural properties of surfactant suspensions by electronic spin resonance and surface tension measurements. Our results showed that albumin seems to be responsible for macrostructure disaggregation and increased rigidity in the hydrophobic region, but it did not affect surfactant activity.

Effect of serum proteins on an exogenous pulmonary surfactant: ESR analysis of structural changes and their relation with surfactant activity.

The study of the structural changes in surfactant microviscosity and bilayer organization would help to understand the mechanisms by which surfactant could be inactivated by serum components. The in vitro effects of human serum, albumin and gamma-globulin on dynamic and structural properties of surfactant suspensions and their heavy fractions were evaluated by electronic spin resonance and surface tension measurements. Our results showed that albumin and serum modified the aggregation state, transforming the active into inactive subtype, but only serum decreased the fluidity in the polar region and inactivated surfactant.

Influence of serum protein and albumin addition on the structure and activity of an exogenous pulmonary surfactant.

The comparative analysis of the deleterious action of albumin and total serum proteins (SP) might help to understand the nature of the interaction surfactant--SP. This study evaluated the effects of serum proteins and albumin on bulk shear viscosity, surface tension, surface area reduction, and the ratio between the light and heavy subtypes of surfactant suspensions. Our results showed a correlation between the bulk viscosity and aggregation degree of surfactant suspensions.

Antioxidant effects of water- and lipid-soluble nitroxide radicals in liposomes.

Liposomes are today useful tools in different fields of science and technology. A lack of stability due to lipid peroxidation is the main problem in the extension of the use of these formulations. Recent investigative works have reported the protective effects of stable nitroxide radicals against oxidative processes in different media and under different stress conditions.