Search results for "phospholipids"
showing 10 items of 197 documents
Formation of protein multilayers and their competitive replacement based on self-assembled biotinylated phospholipids.
1994
Based on specific recognition processes the build-up of protein multilayers was achieved using streptavidin layers as a docking matrix. For this purpose, streptavidin was organized at biotin-containing monolayers, liposomes, and self-assembled layers on gold. Thus, mixed double and triple layers of streptavidin, Con A, Fab fragments, and hormones were prepared and characterized by fluorescence microscopy and plasmon spectroscopy. Using biotin analogues with lower binding constants several cycles of multilayer formation followed by competitive replacement could be achieved.
2D dynamical arrest transition in a mixed nanoparticle-phospholipid layer studied in real and momentum spaces
2015
AbstractWe investigate the interfacial dynamics of a 2D self-organized mixed layer made of silica nanoparticles interacting with phospholipid (DPPC) monolayers at the air/water interface. This system has biological relevance, allowing investigation of toxicological effects of nanoparticles on model membranes and lung surfactants. It might also provide bio-inspired technological solutions, exploiting the self-organization of DPPC to produce a non-trivial 2D structuration of nanoparticles. The characterization of interfacial dynamics yields information on the effects of NPs on the mechanical properties, important to improve performances of systems such as colloidosomes, foams, creams. For thi…
Computer Simulations of the Electric Interactions between the Phospholipid Head-Groups and Ionic Admixtures in the Membrane Surface
2001
Some phospholipids (e.g. lecithin) form a system of electric dipoles on the membrane surface layer. In the case of lecithin the positive dipole charge is located on the choline and the negative one on the phosphoric molecule group. These dipoles are arranged almost parallel to the membrane surface. Taking the dipole membrane structure as a base for further investigations, a computer model of the electrostatic interaction between the dipole system and the ionic admixture was investigated. The model presumes hexagonal centered or a rectangular flat geometry of the 121 dipoles distribution. The dipoles may rotate freely around round the motionless symmetry axis perpendicular to the system surf…
Qualitative and quantitative evaluation of solitary thyroid nodules with contrast-enhanced ultrasound: initial results
2005
To assess the feasibility of contrast-enhanced ultrasound (CEUS) of the thyroid gland and to evaluate the potential of this method for characterising solitary thyroid nodules.18 patients affected by solitary thyroid nodules (size range: 0.6 to 3.6 cm; mean: 1.8 cm) confirmed by surgery (nine papillary carcinomas, four follicular carcinomas, three hyperplasias, one follicular adenoma and one Plummer’s adenoma) underwent pulse inversion US at low M.I. (0.06 to 0.08) after i.v. injection of a 2.4-mL bolus of SonoVue. Baseline echogenicity and the dynamic enhancement pattern of each nodule, in comparison with adjacent thyroid parenchyma, were assessed. Signal intensity values on grey-scale imag…
Receptors Linked to Hydrolysis of Choline Phospholipids: the Role of Phospholipase D in a Putative Mechanism of Signal Transduction
1990
The structure and basic functions of biomembranes are essentially determined by the lipid bilayer. In contrast, specific membrane functions, such as signal recognition and transduction and transport processes, have been preferentially attributed to proteins that are embedded in the outer or inner leaflet of this bilayer or may span the membrane up to five times or more, as in the case of receptor molecules. The segregating view of membrane protein and lipid functions may have delayed a broad research interest in the dynamic interactions between these components of the membrane. The present review is devoted to such a recently discovered interaction: the coupling of receptor activation and h…
Lipid phase transition in saccharide-coated cholate-containing liposomes: coupling to the surrounding matrix.
2005
We performed FTIR measurements on cholate-containing liposomes (CCL) embedded in saccharide (trehalose or sucrose) matrixes with different contents of residual water. We obtained information on the CCL phase transition following the thermal evolution (310-70 K) of the IR spectrum of the carbonyl moieties of phospholipids in the frequency range 4225-4550 cm(-1). Furthermore, we simultaneously followed the thermal evolution of the water association band, which gave information on the behavior of the surrounding water-saccharide matrix. The analysis revealed a small sub-band of the water association band present in CCL but not in cholate-free liposomes, the thermal evolution of which is tightl…
Degradation of phosphatidylethanol counteracts the apparent phospholipase D-mediated formation in heart and other organs.
2003
Phosphatidylalcohols, such as phosphatidylethanol (PEth), are formed from phosphatidylcholine in the presence of a primary alcohol (e.g., ethanol). This 'transphosphatidylation' reaction is used as specific phospholipase D (PLD) assay. Accumulation of PEth in tissues is recognized as a reliable measure of PLD activity, as PEth is allegedly metabolically stable. The general validity of this assumption was reinvestigated in isolated rat heart, small intestine and brain slices. The half-times of 3H-PEth degradation (labelled with 3H-myristic acid and preformed by ethanol exposure for 30 min) were about 1 h in heart and small intestine, but 17 h in brain. As the formation of PEth is superimpose…
Efficacy and tolerability of a fixed dose combination of cortex phospholipid liposomes and cyanocobalamin for intramuscular use in peripheral neuropa…
2019
Peripheral neuropathies are frequently encourtered in clinical practice and are assiociated with a major impairment in quality of life . Howewvwr, their management reamans poor, and current therapies are often burdened with major side effects and can present poor efficacy on pain and functionality. Therefore, it has been suggested that the combination of two or more different drugs may improve analgesis efficacy and reduce side effects. Tricortin 1000 is formulated with 12 mg of Brain cortex phospholipid liposomes + 1000 microgrammi of Cyanocobalamin injectable (PL+ CNCb1) for intramuscolar use and is indicated in the tratment of poly-algo-neuropathic syndromes. This combination exerts a ma…
A time course investigation of vitamin A level and lipid composition of the liver endoplasmic reticulum in rats following treatment with congeneric p…
1990
Abstract The drug metabolizing enzyme activities, the vitamin A content and the fatty acid composition in the endoplasmic reticulum membrane were studied in rat liver after a single injection of the polychlorobiphenyls (PCBs) 3,3′,4,4′-tetrachlorobiphenyl [(3,4)2Cl] or 2,2′,4,4′,5,5′-hexachlorobiphenyl [(2,4,5)2Cl], 300 μ mol/kg each. The microsomal vitamin A level was markedly lowered 3 days after treatment with (3,4)2Cl, a coplanar type inducer of cytochrome P-450. A marked increase in microsomal AHH and UDPGT activities occurred within 3 days after injection of (3,4)2Cl whereas (2,4,5,)2Cl treatment enhanced APDM activity only. Arachidonic, stearic and linoleic acid microsomal contents w…
Toxicity of fatty acid hydroperoxides towards Yarrowia lipolytica: Implication of their membrane fluidizing action
2007
Abstract Linoleic acid hydroperoxide (HPOD), substrate of hydroperoxide lyase, an enzyme of the lipoxygenase pathway, can be transformed into many aromatic compounds, the so-called “green notes”. The presence of linoleic acid hydroperoxide in the culture medium of Yarrowia lipolytica, the yeast expressing the cloned hydroperoxide lyase of green bell pepper, undoubtedly exerted an inhibition on the growth and a toxic effect with 90% of yeast cells died after 120 min of exposition in 100 mM HPOD solution. The increase in cell membrane fluidity evaluated by measuring fluorescence generalized polarization with the increasing concentration of HPOD in the medium confirmed the fluidizing action of…