Quantitative microanalysis of bile acids in biological samples

Nakayama, Fumio

doi:10.1016/s0021-9673(01)81463-1

Cited by 19 publications

(14 citation statements)

References 14 publications

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“…Measurements were conducted at a concentration of 2 mM, reflecting the mean concentration range for combined bile acids in human gall-bladder bile (Arianoff, 1966;Nakayama, 1967) after dilution to 2 % (v/v) in buffer.…”

Section: Discussionmentioning

confidence: 99%

Chemotactic response of Helicobacter pylori to human plasma and bile

Worku

Karim

Spencer

et al. 2004

Journal of Medical Microbiology

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To clarify further the role of chemotaxis in Helicobacter pylori colonization, the in vitro bacterium response to human plasma and bile (secretions containing chemoeffector compounds that are present in the gastric mucus layer) was examined. Human plasma, after dilution to 1 % (v/v) with buffer, was found to be a chemoattractant for the motile bacillus. Human gall-bladder bile, after dilution to 2 % (v/v) with buffer, was found to be a chemorepellent, but did not cause the motility of the bacillus to be diminished after prolonged exposure. The basis of the chemoattractant effect of plasma was explored by examining how urea and 12 amino acids found in plasma affected the taxis of H. pylori. Urea and the amino acids histidine, glutamine, glycine and arginine were the strongest chemoattractants. Other amino acids were chemoattractants, with the exceptions of aspartic and glutamic acids, which were chemorepellents. The basis of the chemorepellent effect of bile was explored by examining how the six most abundant conjugated bile acids in human bile affected the taxis of H. pylori. All the bile acids were chemorepellents, with the greatest effects being demonstrated by taurocholic and taurodeoxycholic acids. The implications of these findings for H. pylori colonization of gastric epithelium are discussed.

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Section: Discussionmentioning

confidence: 99%

Chemotactic response of Helicobacter pylori to human plasma and bile

Worku

Karim

Spencer

et al. 2004

Journal of Medical Microbiology

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“…Second, reflux of bile from the intestine into the stomach normally occurs following a meal (38). Bile salt concentrations of ϳ2 mM (ϳ1,000 g/ml) are typically found in human bile (34). A few studies have investigated the bactericidal effects of bile salts on H. pylori using rich medium containing serum or blood (which contains cholesterol) (14,15,22,33), but no study has yet investigated the effects in a chemically defined, cholesterolfree medium, nor has there been a comprehensive comparison among the many bile salt derivatives found in vivo.…”

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confidence: 99%

Role of the HefC Efflux Pump inHelicobacter pyloriCholesterol-Dependent Resistance to Ceragenins and Bile Salts

et al. 2011

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The human gastric pathogen Helicobacter pylori modifies host cholesterol via glycosylation and incorporates the glycosylated cholesterol into its membrane; however, the benefits of cholesterol to H. pylori are largely unknown. We speculated that cholesterol in the H. pylori membrane might alter the susceptibility of these organisms to membrane-disrupting antibacterial compounds. To test this hypothesis, H. pylori strains were cultured in Ham's F-12 chemically defined medium in the presence or absence of cholesterol. The two cultures were subjected to overnight incubations with serial 2-fold dilutions of 10 bile salts and four ceragenins, which are novel bile salt derivatives that mimic membrane-disrupting activity of antimicrobial peptides. H. pylori cultured with cholesterol was substantially more resistant to seven of the bile salts and three ceragenins than H. pylori cultured without cholesterol. In most cases, these cholesterol-dependent differences ranged from 2 to 7 orders of magnitude; this magnitude depended on concentration of the agent. Cholesterol is modified by glycosylation using Cgt, a cholesteryl glycosyltransferase. Surprisingly, a cgt knockout strain still maintained cholesterol-dependent resistance to bile salts and ceragenins, indicating that cholesterol modification was not involved in resistance. We then tested whether three putative, paralogous inner membrane efflux pumps, HefC, HefF, or HefI, played a role. While HefF and HefI appeared unimportant, HefC was shown to play a critical role in the resistance to bile salts and ceragenins by multiple methods in multiple strain backgrounds. Thus, both cholesterol and the putative bile salt efflux pump HefC play important roles in H. pylori resistance to bile salts and ceragenins.

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“…Toyoda (18) analysed calcium bilirubinate and total pigment äs early äs 1966. Although some investigators have analysed a large number of different components in gallstones (e. g. Trotman et al (7) describe 9 components, while Nakayama (12) even describes the analysis of 16 different components), cholesterol, bilirubin and calcium are the most important ones.…”

Section: Discussionmentioning

confidence: 99%

“…One exception is Nakayama (12), who found a recovery of cholesterol of 91 % and of bilirubin of 93%. For the imprecision of cholesterol he found a CV of 0.7%, for bilirubin 2.7% and for calcium 3.9%.…”

Section: Introductionmentioning

confidence: 99%

Chemical Analysis of Gallstones

Steen¹,

Blijenberg²

1991

Clinical Chemistry and Laboratory Medicine

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Summary:A new promising treatment for patients with symptomatic cholelithiasis is extracorporeal shock wave lithotripsy. In Order to learn how to Interpret the computed tomographic (CT) densities of gallstones measured in vivo, our radiologists asked the clinical chemistry laboratory to analyse cholesterol, bilirubin and calcium in gallstones. No reference methods for the analysis of gallstones have been described. A literature search for manageable quantitative methods for these analyses was not successful. Among the different Xray diffraction, infrared and chemical analyses described, we could find no well documented analyses that have been compared with reference methods or proposed reference methods for serum. This finding prompted us to develop chemical methods for cholesterol, bilirubin and total calcium in gallstones starting from (proposed) reference methods for serum and to investigate the accuracy, imprecision and linearity of these methods.

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Quantitative microanalysis of bile acids in biological samples

Cited by 19 publications

References 14 publications

Chemotactic response of Helicobacter pylori to human plasma and bile

Chemotactic response of Helicobacter pylori to human plasma and bile

Role of the HefC Efflux Pump inHelicobacter pyloriCholesterol-Dependent Resistance to Ceragenins and Bile Salts

Chemical Analysis of Gallstones

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