OBJECTIVE To assess the physicochemical characteristics of sperm plasma membrane and to evaluate the immunohistochemical expression of transmembrane and cytoskeletal proteins in spermatozoa isolated from normospermic fertile donors and asthenozoospermic infertile patients. DESIGN Case-control study. SETTING Academic male infertility center. PATIENT(S) Twenty-five infertile patients affect...

The lipid fluidity of microsomal membranes from the petals of cut carnation flowers decreases as the flowers senesce. A comparable change in fluidity was induced by in vitro aging of microsomal membranes from young flowers under conditions in which membranous lipoxygenase-like activity was active. There was no change in fluidity when the membranes were aged in the presence of inhibitors of lipo...

Porcine corpora lutea plasma membranes were treated with neutral lipids from hen egg yolk and a special mixture consisting of 70% neutral lipids, 20% phosphatidylcholine and 10% phosphatidylethanolamine. Membrane fluidity, as determined by fluorescence polarization of DPH, significantly increased already after 30 min of incubation of the membranes with lipids. The fluidization effect of neutral...

Since lysosomes are prone to osmotic lysis, we have examined the correlation between their physical state and sensitivity to osmotic challenge, using agents which modify membrane fluidity. The latency loss of beta-hexosaminidase after an incubation in hypotonic sucrose medium was followed under different conditions of membrane fluidity, recorded by steady-state fluorescence anisotropy of 1,6-di...

The effects of the surfactants, alcohol ethoxylate, amine ethoxylate, amine oxide and SDS on cell membranes were investigated using the lipid soluble spin label 5-doxyl stearic acid (5-DS). Electron paramagnetic resonance (EPR) spectroscopy revealed that the action of the surfactants was to significantly increase membrane fluidity of Proteus mirabilis, Staphylococcus aureus and Saccharomyces ce...

The mechanism by which dietary cis-unsaturated fatty acids lower low density lipoprotein (LDL) cholesterol is unknown. Because cis-unsaturated fatty acids incorporated into cell membranes increase membrane fluidity and, as a result, can alter membrane-dependent cell functions, we examined LDL binding, uptake, and degradation in upregulated U937 monocytes enriched in membrane oleate, a monounsat...

Insulin, Leptin, and Membrane Microviscosity in Blood Pressure Regulation To the Editor: We read with great interest the recent article by Vecchione and colleagues1 dealing with a possible link between insulin and leptin in the regulation of vascular tone in rats.1 The results of their presented study demonstrated that insulin and leptin cooperated in the modulation of vascular tone through enh...

Insulin, Leptin, and Membrane Microviscosity in Blood Pressure Regulation To the Editor: We read with great interest the recent article by Vecchione and colleagues1 dealing with a possible link between insulin and leptin in the regulation of vascular tone in rats.1 The results of their presented study demonstrated that insulin and leptin cooperated in the modulation of vascular tone through enh...

Hemolysis of human or chicken erythrocytes by Sendai virus causes a change in the structure of the erythrocyte membrane lipid bilayer that can be detected by spin label electron spin resonance. In the intact erythrocyte, the phosphatidylcholine derivative spin label exists in a more rigid environment than the corresponding phosphatidylethanolamine label. Virus-induced hemolysis tends to abolish...

Glycosylation, oxidation and other post-translational modifications of membrane and transmembrane proteins can alter lipid density, packing and interactions, and are considered an important factor that affects fluidity variation in membranes. Red blood cells (RBC) membrane physical state, showing pronounced alterations in Type 1 diabetes mellitus (T1DM), could be the ideal candidate for monitor...