PubMed Health⌕ Search

Biomedical subjects

S Lindenbaum

Publications and source records attributed to S Lindenbaum.

28 records · Page 2Linked to original sources
PubMed1982

Association of deoxycholic acid in organic solvents.

The distribution of deoxycholic acid (I) between aqueous buffer and an organic phase consisting of isooctane-1-octanol (70:30, v/v) (System A) or isooctane-chloroform (80:20, v/v) (System B) was studied. The distribution isotherms suggested that I associates strongly in the organic Systems A and B unlike in pure 1-octanol. Therefore, a previous model, describing distribution of bile salts between 1-octanol and aqueous buffer, was modified to include association of I in the organic phases to describe distribution behavior. The treatment suggested that I exists as monomer and dimer in System A with a dimerization constant of 820 M-1. A model consisting of monomer-tetramer-hexamer in the organic phase best describes the data for System B. The data support the view that association in the organic phase is due to hydrogen bonding between bile acid molecules.

1-Octanol↗
PubMed1981

Implications for women of changing marriage transactions in Bangladesh.

Recent changes in marriage transactions in Bangladesh have led increasingly to a shift in the burden of marriage expenses from the groom's family of the bride. This reversal in the direction of wealth exchanges, which may not be in the best interest of the bride, reflects social and economic changes that have increased the income potential of the groom, which now surpasses previously valued attributes of the bride. In this paper, anthropologist Shirley Lindenbaum examines the effects of these changes on women and their implications for female fertility and mortality. An earlier version of this paper was presented to the New York Academy of Science on 25 February 1980.

Adolescent↗
PubMed1979

Enthalpy of bile salt-lecithin mixed micelle formation.

The enthalpies for the dissolution of lecithin by sodium salts of cholic, deoxycholic, and chenodeoxycholic acids and their glycine and taurine conjugates are reported. Exothermic enthalpies were found in each case. It is suggested that heat evolution is due to a bile salt-lecithin interaction other than hydrophobic interactions. These results provide strong support for the "mixed disk" model for the complex lecithin-bile salt micelle, which requires that a substantial fraction of the bile salt molecules be incorporated within a lecithin bilayer where hydrogenbonded pair formation can occur. Calorimetric studies of the interaction between sodium cholate and nonionic, cationic, and anionic detergents yielded exothermic heats. These results suggest that these bile salt molecules partition into the detergent micelle interior as hydrogenbonded pairs.

Bile Acids and Salts↗
PubMed1978

Enhancement of bioavailability of a hydrophobic amine antimalarial by formulation with oleic acid in a soft gelatin capsule.

The relative availability of the orally administered hydrophobic antimalarial alpha-(dibutylaminomethyl)-6,8-dichloro-2-(3',4'-dichlorophenyl)-4-quinolinemethanol (I) from two dosage forms was determined in beagle dogs. Compound I was soluble in oleic acid to the extent of 23.5% (w/w), and oleic acid was suitable for encapsulation in soft gelatin capsules. The availability of I formulated as its hydrochloride salt in a standard hard gelatin capsule formulation was significantly lower than that of I formulated in a soft gelatin capsule with oleic acid as the solvent. A 20% solution of I in oleic acid (soft gelatin capsules) maintained at 23 degrees provided 4% of the oleic acid ester of I iwithin 1 month. Further reaction, however, was not seen over 2 years.

Animals↗
PubMed1976

Enhancement of solubility of drug salts by hydrophilic counterions: properties of organic salts of an antimalarial drug.

Judicious choice of the salt form of a drug can greatly affect the aqueous solubility and formulation of the compound. The objective of this work was to demonstrate the effect of various counteranions on the aqueous solubility of the antimalarial agent alpha-(2-piperidyl)-3, 6-bis(trifluoromethyl)-9-phenanthrenemethanol. Several organic salts of this drug were studied. The methods of synthesis, the apparent aqueous solubilities, and in vitro dissolution tests for these salts are reported. The lactate salt was 200 times as soluble as the hydrochloride salt. This enhanced solubility suggests that parenteral administration of this drug may now be feasible.

Antimalarials↗
PubMed1975

Binding of bile acids to cholestyramine at gastric pH conditions.

The binding of bile salts to cholestyramine was studied under varying conditions of pH and added electrolyte. The taurine-conjugated bile salts were strongly absorbed by the anion-exchange resin at low pH and in the presence of chloride anions. Glycocholic acid binding was very weak at low pH but increased strongly with increasing pH. The presence of chloride ions strongly decreased the amount of glycocholate bound by the anion-exchange resin.

Adsorption↗
PubMedDate not supplied

Counter-ion binding by bile acid solutions.

The binding of Ca2+ to micelles of glycine and taurine bile acid conjugates was studied using a Ca2+-specific electrode. An investigation of the effect of buffer concentration, pH, added electrolyte and lecithin was also performed. The results indicate that the binding of Ca2+ to bile salt micelles is dependent on the number of hydroxyl groups on the steroid nucleus and on the nature of the head conjugating group, namely, glycine or taurine. It is speculated that the binding of Ca2+ to bile salt micelles may act as one mechanism to lower Ca2+ activity in bile and, thus, reduce its tendency to precipitate as insoluble calcium salts and further growth into gallstones.

Bile Acids and Salts↗
PubMedDate not supplied

Kinetics and thermodynamics of dissolution of lecithin by bile salts.

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. The rate of dissolution of lecithin and mixed micelle formation decreased in the order: chenodeoxycholate greater than deoxycholate greater than cholate greater than ursodeoxycholate. Kinetic solvent isotope studies in D2O, along with measurement of enthalpies of mixed micelle formation both in H2O and D2O, suggest that formation and stabilization of mixed micelles are related to "hydrophobicity" as estimated by high performance liquid chromatography retention factors.

Bile Acids and Salts↗