Egg lecithin-cholesterol

Figure 3 Molecular relaxivities of liposomes with different Gd-containing membranotropic chelators. Liposomes (egg lecithin cholesterol chelator = 72 25 3) were prepared by consecutive extrusion of lipid suspension in HEPES buffered saline, pH 7.4, through the set of polycarbonate filters with pore size of 0.6, 0.4, and 0.2 mm. Liposome final size was between 205 and 225 nm. Gd content determination was performed by Galbraith Laboratories, Inc. The relaxation parameters of all preparations were measured at room temperature using a 5-MHz RADX nuclear magnetic resonance proton spin analyzer. The relaxivity of liposomes with polymeric chelators is noticeably greater because of the larger number of Gd atoms bound to a single lipid residue [16].

Figure 4 Transverse scan of axillary and subscapular lymph nodes in a rabbit 5 min postinjection of Gd-containing liposomes. Liposomes (egg lecithin cholesterol Gd-poly-NGPE = 70 25 5, 20 mg total lipid) were injected subcutaneously into the forepaw of anesthesized rabbit in 0.5 mL of HEPES-buffered saUne. Images were acquired by using a 1.5 Tesla GE Signa MRl scanner operated at fat suppression mode and Tj-weighted pulse sequence [16].

Figure 3. Effect of lipid composition on surface pressure of films of egg lecithin-cholesterol in interaction with rabbit y-globulin at 1 digram/ ml.

Figure I. Schematic of interaction of calcium ion with dioleoyl, egg, and di-palmitoyl lecithins, and of egg lecithin-cholesterol monolayers...

B Egg lecithin-cholesterol monolayers. Increased spacing between phosphate groups results in strong internal salt linkage preventing binding of Ca2+... 

Egg Lecithin—Cholesterol Monolayers. The average area per molecule in egg lecithin-cholesterol monolayers shows deviation from the additivity rule at all surface pressures (42). The deviation in this case could be explained by the presence of molecular cavities caused by the kink in the oleoyl chain of egg lecithin, which would reduce the average area per molecule at low as well as high surface pressures (Figure lOg). 

The optimum condensation at molecular ratios of 3 to 1 and 1 to 3 in egg lecithin-cholesterol monolayers and 1 to 1 in dipalmitoyl lecithin-cholesterol monolayers (42) do not imply complex formation between lecithin and cholesterol but rather suggest average geometrical arrangements of these molecules. 

Figure 7. Sugar permeability plot for bilayer lipid membrane (egg lecithin-cholesterol in n-decane) at 25 °C. The slope of the plot before and after addition of extract is equal to the permeability coefficient. Passive diffusion of D-[ C]glucose (O) and facilitated diffusion ( ) on addition of band 4.5 (sugar transporter) at a concentration of 0.99 (Jig cm to the trans side of the bilayer. (Reproduced with permission from Ref. 44. Copyright 1982 Elsevier Science.)...

Figure 7. Transmembrane potential value on bilayer lipid membrane (made from egg lecithin + cholesterol) depending on FMN concentration in the system...

Zull et al. (1968) have used the ATR technique (see Chapter 3) to obtain spectra of solid films of egg lecithin-cholesterol mixtures. In films cast from organic solvents, cholesterol can form a sterol phospholipid (2 1) complex which involves interaction of the cholesterol —OH with lecithin polar groups. Association with the quaternary nitrogen of lecithin was ruled out, and the formation of a hydrogen bond between... 

Uncharged (ingredients egg lecithin-cholesterol, weight ratio 33 4.64 mg)... 

Rosenqvist E, Michaelsen TE, Vistnes Al. Effect of streptolysin O and digitonin on egg lecithin/cholesterol vesicles. Biochim Biophys Acta. 1980 600(1) 91-102. 

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