A Novel Design of Continuous Culture for In Vitro Formation of Gallstones by Salmonella Typhi

The current research focused on detecting the role of Salmonella typhi (S. typhi) in the formation of gallbladder stones in the laboratory following isolation and diagnosis of S. typhi from bile samples of patients suffering from gallstone. Locally and for the first time, a novel continuous culture was designed, and Brilliant Green Bile Broth (BGBB) was used by adding 60% cholesterol and 20% Calcium Carbonate (CaCO3) to form the gallstone nucleation. The continuous culture was inoculated with 1% S. typhi then incubated in optimal conditions for 20 days. After 14 days of incubation, results revealed the formation of spherical aggregations with various sizes in the test flask compared to the control flask. Moreover, an increase in the size of the stone formed was observed after 20 days of incubation. The morphology of cholesterol and Calcium Carbonate crystals were studied using light, fluorescent and scanning electron microscopes, and the functional groups were diagnosed using the Fourier transform infrared spectrometry (FTIR) technique. KEYWORDS Biliary microbiota, model Bile, polysaccharide production

Metastable and equilibrium phase diagrams of unconjugated bilirubin IXα as functions of pH in model bile systems: Implications for pigment gallstone formation

Metastable and equilibrium phase diagrams for unconjugated bilirubin IXα (UCB) in bile are yet to be determined for understanding the physical chemistry of pigment gallstone formation. Also, UCB is a molecule of considerable biomedical importance because it is a potent antioxidant and an inhibitor of atherogenesis. We employed principally a titrimetric approach to obtain metastable and equilibrium UCB solubilities in model bile systems composed of taurine-conjugated bile salts, egg yolk lecithin (mixed long-chain phosphatidylcholines), and cholesterol as functions of total lipid concentration, biliary pH values, and CaCl2 plus NaCl concentrations. Metastable and equilibrium precipitation pH values were obtained, and average pKa values of the two carboxyl groups of UCB were calculated. Added lecithin and increased temperature decreased UCB solubility markedly, whereas increases in bile salt concentrations and molar levels of urea augmented solubility. A wide range of NaCl and cholesterol concentrations resulted in no specific effects, whereas added CaCl2 produced large decreases in UCB solubilities at alkaline pH values only. UV-visible absorption spectra were consistent with both hydrophobic and hydrophilic interactions between UCB and bile salts that were strongly influenced by pH. Reliable literature values for UCB compositions of native gallbladder biles revealed that biles from hemolytic mice and humans with black pigment gallstones are markedly supersaturated with UCB and exhibit more acidic pH values, whereas biles from nonstone control animals and patients with cholesterol gallstone are unsaturated with UCB.

Sodium cholate sorption on N-octadecylpectinamide in comparison with cholestyramine

<i>N</i>-Octadecylpectinamide is hydrophobically modified HM citrus pectin. Previously, it had been prepared by heterogeneous amino-de-alkoxylation of initial pectin with <i>n</i>-octadecylamine in dimethylsulphoxide and characterised as potential hydrophobic sorbent and cholesterol lowering agent. The sorption properties of <i>N</i>-octadecylpectinamide were analysed in comparison with cholestyramine, an effective bile acid sequestrant. Sorption experiments were carried out using sodium cholate as a model bile acid. Cholate concentration was estimated by enzymatic spectroscopic method. Sorption kinetics curves and sorption isotherms of both sorbents were constructed and analysed.