Search results for "bile acid"
showing 10 items of 118 documents
Methods for diagnosing bile acid malabsorption: a systematic review
2019
Abstract Background Bile acid malabsorption (BAM) and bile acid-related diarrhea represent an under-recognized cause of chronic diarrhea mainly because of limited guidance on appropriate diagnostic and laboratory tests. We aimed to perform a systematic review of the literature in order to identify and compare the diagnostic accuracy of different diagnostic methods for patients with BAM, despite a proven gold standard test is still lacking. Methods A PubMed literature review and a manual search were carried out. Relevant full papers, evaluating the diagnostic accuracy of different methods for BAM, were assessed. Available data were analyzed to estimate the sensitivity and specificity of each…
Etude du rôle du récepteur nucléaire CAR, Constitutive Androstane Receptor, dans le métabolisme des lipides et la susceptibilité à l'athérosclérose
2011
The Constitutive Androstane Receptor (CAR) belongs to the subfamily of nuclear receptors NR1. Initially described as an orphan receptor, CAR is activated by a large number of exogenous molecules and acts as a xenosensor. The activation of CAR by these ligands stimulates transcription of phase I, II and III enzymes required for the detoxification and elimination of xenobiotics. Furthermore CAR is also involved in the metabolism of endogenous molecules such as bile acids, bilirubin or thyroid hormones. CAR has recently been the subject of numerous independent studies that have highlighted his involvement in major metabolic pathways including gluconeogenesis, lipogenesis and lipoprotein metabo…
Ultrasound accelerated esterification of bile acids
2004
In this study power ultrasound accelerated esterification reactions of some model substances and bile acids were done. In the model reactions the best result was 19-fold increase in the reaction rate when using ultrasound and the temperature was allowed to rise during the irradiation. In the case of bile acid methyl esters a clear increase in the reaction rates was also observed by ultrasonic irradiations.
Deoxycholic Acid Methyl Ester — a Novel Bacterial Metabolite of Cholic Acid
1985
Summary Methyl deoxycholate was identified as a novel bacterial metabolite of cholate, produced anaerobically by strains of most saccharolytic Bacteroides species ( B. distasonis, B. eggerthii, B. fragilis, B. incommunis, B. thetaiotaomicron, B. uniformis, B. variabilis, B. vulgatus , and unnamed species). It was also detected with a few strains of Eubacterium and Lactobacillus species. Among 2476 freshly isolated human fecal cultures the frequency of carboxyl group esterification was comparable with that of 7α-dehydroxylation (92 versus 102 cultures). Both activities were, however, lost for unknown reasons after serial transfers. Two of ten mixed fecal cultures tested esterified 3α,7α- or …
Gnotobiotische untersuchungen an SPF-Mäusen im rahmen einer studie zur tumorentwicklung im kolon nach cholezystektomie
1985
Summary The relation between cholecystectomy and colon carcinogenesis has not been fully elucidated. As bacteria may be involved in the carcinogenic process, we investigated the effect of cholecystectomy and dimethylhydrazine (DMH) administration to SPF NMRI mice with regard to tumour genesis and bacterial colonisation of the intestine. It results from this study that cholecystectomy does not influence tumour genesis and that 6–7 months post operationem and DMH administration tumours and bacteria originally not found in the animals develop: Clostridia, eubacteria spec, which cannot be differentiated and E. lentum. Theses changes appear in group II of mice (laparotomy and DMH) and group III …
Epimerization, oxidation and reduction of bile acids by Eubacterium lentum
1984
Summary Twenty-eight strains of Eubacterium lentum were divided into five groups on the basis of their ability to metabolize cholic acid and dehydrocholic acid: (I) Strains with 3α- and 3/β-dehydrogenating activities (1 strain), (II) strains with 12α-dehydrogenating activity (5 strains), (III) strains with 3α-, 3β-, 7α-, and 12α-dehydrogenating activities (8 isolates), (IV) transition stages between group II and III (1 strain), (V) strains devoid of any measurable bile acid metabolizing activities or with only trace activities (11 isolates). Using appropriate bile acids it was demonstrated that hydroxyl or keto groups at positions C 3 , C 7 , and C 12 did not influence bile acid transformat…
Self-assembly properties of bile acid derivatives of L-cysteine, L-valine and L-serine alkyl esters
2012
Comprehensive self-assembly studies for nine bile acid amides of amino acid esters are reported. The number of the hydroxyl groups attached to the steroidal skeleton and the character of the amino acid ester moiety were used as variables when examining the self-assembly properties of the compounds. Two of the compounds were shown to undergo self-assembly leading to organogelation. In addition, preliminary self-assembly studies in aqueous mixtures of polar organic solvents were conducted. Microscopic methods (optical microscopy and scanning electron microscopy) were utilised in order to gain a deeper insight into the self-assembled structures. Furthermore, single-crystal X-ray structures for…
Separation of homologues and isomers of linear alkylbenzenesulfonates by capillary electrophoresis with sodium dodecyl sulfate, carboxylic acids and …
2003
The ability of several anionic compounds, including carboxylic and dicarboxylic acids, sodium dodecyl sulfate (SDS), and sodium deoxycholate (SDC) and other bile salts, to separate the C(10)-C(13) homologues and the corresponding 20 positional isomers of linear alkylbenzenesulfonates (LAS) by capillary electrophoresis was studied. Up to 19 peaks and a shoulder were observed with a background electrolyte (BGE) containing 10 mM phosphate (pH 6.8), 30% acetonitrile and 40 mM SDS, and 18 peaks were obtained with a BGE containing 10 mM borate (pH 9), 40% ethanol and 40 mM palmitic acid (PA). Resolution increased with the alkyl chain length of the carboxylic acid. Dicarboxylic acids with a short …
Imprinted Polymers for Selective Adsorption of Cholesterol from Gastrointestinal Fluids
1998
A series of highly cross-linked terpolymers of methacryloylated cholesterol or bile acid methyl esters, methacrylic acid, and ethyleneglycol dimethacrylate were prepared in the presence or absence ...
Bile acid–amino acid ester conjugates: gelation, structural properties, and thermoreversible solid to solid phase transition
2010
Design, synthesis, and gelation properties of three novel biocompatible bile acid–L-methionine methyl ester conjugates are presented. Two of the conjugates have been shown to undergo self-assembly leading to organogelation in certain aromatic solvents. The properties of these gels have been investigated by conventional methods typical for molecular gel studies along with 13C CPMAS NMR spectroscopic studies of the native gel. In addition, properties in solid and solution states for all three compounds have been investigated, and single crystal X-ray structures of all compounds determined. Furthermore, powder X-ray diffraction studies have revealed that compound 1 undergoes a dynamic and reve…