Kinetics and Thermodynamics of Dissolution of Lecithin by Bile Salts

Siegfried Lindenbaum, Natarajan Rajagopalan – 1 September 1984 – The kinetics of dissolution of dispersions of egg phosphatidylcholine (lecithin) by bile salts was studied by observing the decrease in turbidity as mixed micelles of lecithin and bile salts were formed. The rate of dissolution of lecithin corresponding to formation of mixed micelles was studied in the presence of dihydroxy bile salts, sodium deoxycholate, sodium chenodeoxycholate, sodium ursodeoxycholate and one trihydroxy bile salt, sodium cholate.

Bile Salt Micelles: Nuclear Magnetic Resonance Spectroscopy and Crystallographic Studies

Stephen Barnes – 1 September 1984 – Studies of bile salt structure using nuclear magnetic resonance (NMR) and X‐ray crystallography have suggested that micellar association of bile salts is a function of side chain length and of packing of the side chain and the steroid nucleus. Lanthanide NMR probe analysis has been used to determine the structure of what is probably the monomer of the bile salt glycocholate.

Dynamic Micelle Laser Light Scattering Studies of the to Vesicle Transition in Model and Native Bile

Peter Schurtenberger, Norman A. Mazer, Werner Känzig – 1 September 1984 – Using quasielastic light scattering, we investigated the formation of vesicles produced spontaneously by diluting a mixed micellar solution of bile salt and lecithin beyond the micellar phase boundary. The vesicles were nearly monodisperse, and their size varied between 120 to 500 A depending upon the dilution conditions. A systematic study of the dependence of the vesicle size upon the bile salt and lecithin concentration was made and interpreted in terms of a simple equilibrium model.

Size of Bile Salt Micelles: Techniques, Problems and Results

Josip P. Kratohvil – 1 September 1984 – The current state of the knowledge of the size and the aggregation numbers of micelles formed in solutions of bile salts was evaluated. The experimental techniques considered include static light scattering, sedimentation equilibrium, membrane osmometry, sedimentation velocity and transla‐tional diffusion. The theoretical background of each method is briefly discussed, the working equations are summarized, and the limitations of each technique are enumerated.

Regulation of Low Density Lipoprotein Receptor Function in a Human Hepatoma Cell Line

Alan M. Leichtner, Monty Krieger, Alan L. Schwartz – 1 September 1984 – Low density lipoprotein (LDL) processing was investigated in a human hepatoma‐derived cell line, Hep G2. Hep G2 cells bound, internalized and degraded LDL via a saturable, high affinity (Kd — 2 ± 10−8M) pathway similar to that present in other mammalian cells. Although 80% of the uptake and degradation of 125I‐LDL was inhibited by 40‐fold excess native LDL, the same concentration of methylated LDL, which cannot bind to LDL receptors, had virtually no effect on processing.

Serum α‐L‐Fucosidase: A New Marker for the Diagnosis of Primary Hepatic Carcinoma?

Yves Deugnier, Véronique David, Pierre Brissot, Philippe Mabo, Damien Delamaire, Michel Messner, Michel Bourel, Jean‐Yves Legall – 1 September 1984 – α‐L‐fucosidase, a lysosomal enzyme which catabolizes fucoproteins, was studied in sera from 30 controls, 32 patients with primary hepatic carcinomas, 24 patients with secondary metastatic liver carcinomas and 36 patients with cirrhosis.

Effect of Nuclear Hydroxy Substituents on Aqueous Solubility and Acidic Strength of Bile Acids

Aldo Roda, Adamo Fini – 1 September 1984 – The aqueous solubility and thermodynamic dissociation constants of a representative series of bile acids with varying numbers and configuration of nuclear hydroxyl substituents were determined. The pKa values were calculated by extrapolating pKa' values determined in solutions of aqueous methanol of different mole fractions at 25o C.

Bile Acids and Bile Salts: Ionization and Solubility Properties

Martin C. Carey – 1 September 1984 – The number, position and orientation of nuclear OH substituents profoundly influence the equilibrium solubilities of undissociated bile acids in water. Estimates from several studies range from 5 × 10″8 for lithocholic acid to 1.6 × 10−3 Af for ursocholic acid at 37°C. Fully dissociated sodium bile salts are extremely soluble in water, attaining values as high as 1 to 2 M. However, ionized unconjugated bile salts are appreciably less soluble than their glycine and taurine conjugates.

Chemistry and Enterohepatic Circulation of Bile Acids

Alan F. Hofmann – 1 September 1984 – A brief review is given of the chemistry of bile acids, emphasizing the relationship between chemical structure, physical properties and enterohepatic cycling of the major primary and secondary bile acids. Features of the enterohepatic circulation of primary and secondary bile acids in man are summarized. The effects of bile acid feeding on the composition of the enterohepatic circulation in man are reviewed. Methods for characterizing the enterohepatic circulation of bile acids in man are tabulated.

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