We describe a new and specific method for measurement of lecithin palmitic acid in amniotic fluid. Dipalmitoyl lecithin, the major alveolar surfactant, has previously been estimated by measuring the lecithin-sphingomyelin ratio, total lecithin, total phospholipid phosphorus, and (or) total palmitic acid. Our method is more specific for estimation of dipalmitoyl lecithin, because nonphospholipid...

The literature presents much evidence bearing on the fact that glycerol can play r8les of importance in living processes, not only in the combined state in such physiologically important molecules structurally related to glycerol as glycerides, lecithins, cephalins, phosphatidic acids, ethers, and plasmalogens, but also in the uncombined state as free glycerol. Glycerol itself has been identifi...

We have shown previously that ox and pig bile accelerate in vitro growth of Giardia lamblia. We have now investigated the possible mechanisms by which mammalian biles promote parasite growth. Growth effects of (a) ox, pig, guinea pig, and human biles, (b) pure bile salts, and (c) egg and soybean lecithins were studied in the presence of a lecithin-containing growth medium. Individually, dilute ...

The present study was performed to determine whether the degree of lecithin hydrophobicity regulates bile metastability and, therefore, affects the process of cholesterol crystallization. Supersaturated model bile (MB) solutions were prepared with an identical composition on a molar basis (taurocholate/lecithin/cholesterol, 73:19.5:7.5; total lipid concentration 9 g/dl) except for the lecithin ...

DNA-complexes with platelet-like, cationically modified lipid nanoparticles (cLNPs) are studied with regard to the formation of nanocomposite structures with a sandwich-like arrangement of the DNA and platelets. For this purpose suspensions of platelet-like triglyceride nanocrystals, stabilized by a mixture of two nonionic (lecithin plus polysorbate 80 or poloxamer 188) and one cationic stabili...

The interaction of monolayer cultures of Chinese hamster V79 cells with artificially generated, unilamellar lipid vesicles (approximately 500 A diameter) was examined. Vesicles prepared from a variety of natural and synthetic radiolabeled phosphatidyl cholines (lecithins) were incubated with V79 cells bathed in a simple balanced salt solution. After incubation, the cells were analyzed for exoge...

Surface potentials of mixed monolayers of dicetyl phosphate and eicosanyl trimethylammonium bromide (1:1) were the same on subsolutions of 0.02 M NaCl or 0.01 M CaCl(2), which indicated that ionic phosphate does not interact with Ca(++) in the presence of a neighboring trimethylammonium group. Surface potential-pH plots of dicetyl phosphate, and of dipalmitoyl, egg, and dioleoyl lecithins showe...

Dilute ( ~10% w/v) unsonicated phosphatidylserine dispersions in Hz0 contain spherical particles of a wide size distribution (0.1 to 15 q). The majority have diameters between 0.1 to 2 pm and lack the multilamellar arrangement of bilayers typical of unsonicated lecithin dispersions. Sonication uroduces small thermodynamically unstable vesicles surrounded by a single closed bilayer with an avera...

In this study, 162 students in the 6 year Pharmacy Program at the School of Pharmacy, Iwate Medical University were asked to prepare liposomal preparations using chicken egg yolk and to evaluate their properties with the aim of developing novel liposomes. High-purity lecithins are generally used for preparing liposomes but they are expensive. On the other hand, egg yolk has various components, ...

A basic monomeric phospholipase A2 from the venom of the American water moccasin, Agkistrodon piscivorus piscivorus, undergoes Ca2+-dependent, autocatalytic acylation during the course of hydrolysis of both model and natural phospholipid substrates. Acylation occurs at 2 lysine residues, Lys-7 and Lys-10, in the NH2-terminal alpha-helical segment of the enzyme, and when both positions are fully...