Bile acids detection

Source Prom TLC of selected bile acids Detection and separation, in J. Liq. Chromatogr. Relat. Technol. " ... 

Clinical Analysis. A wide range of clinically important substances can be detected and quantitated using chemiluminescence or bioluminescence methods. Coupled enzyme assay protocols permit the measurement of kinase, dehydrogenase, and oxidases or the substrates of these enzymes as exemplified by reactions of glucose, creatine phosphate, and bile acid in the following ... 

The pink color of the cholesterol begins to fade after 5 min while the color of the bile acids deepens [2]. The visual detection limit in visible light is 1 pg for cholesterol and 2 pg per chromatogram zone for bile acids [2], Fluorimetric detection is more sensitive by a factor of 1000 ... 

Bile acids also yield fluorescence when an only 5% perchloric acid is employed as reagent and the chromatogram is only heated to 100°C until coloration commences [9]. Steroids can also be detected with 2% methanohc perchloric acid [4]. 

Yantrappen et al. [23] for the first time showed the relevance of phase III of the migrating motor complex in the current context, when reporting its absence in 5 of 12 patients with bacterial overgrowth detected by the bile acid breath test and response to antibiotics. 

This method suffered from sensitivity problems initially as the bile-acid molecules lack a chromophore, but did offer the distinct advantage that conjugated bile acids could be determined without hydrolysis. The sensitivity issue was addressed by use of fluorescent derivatives such as dimethoxycoumarin esters with a C18 reverse phase column and were able to resolve endogenous mixtures of bile acids. The combination of hplc and mass-spectroscopy detection has further improved the sensitivity along with providing specific identification, important as the resolution of bile acids by hplc is not as good as capillary column glc. ... 

Additionally, two studies have measured colorectal epithelial cell proliferation and apoptosis in human non-neoplastic mucosa in combination with serum bile acid quantification. Ochsenkuhn et al have reported a positive correlation between serum DCA levels and proliferation measured by flow cytometric cell cycle analysis. However, a more recent study of colorectal adenoma patients failed to detect a correlation between serum DCA and immuno-histochemical Ki-67 antigen labelling. Instead, this latter study revealed a positive correlation between serum DCA and the degree of TUNEL-positive epithelial cell apoptosis. ... 

Polkinghorne, C., Olson, J. M., Gallaher, D. G., and Sorensen, P. W. (2001). Larval sea lamprey release two unique bile acids to the water of a rate sufficient to produce detectable riverine pheromone plumes. Fish Physiology and Biochemistry 24, 15-30. 

A high fiber diet will help by redirecting fat soluble metabolites to the colon rather than bladder. THC is eliminated primarily in the stool via bile acids. Both EMIT and RIA detect a secondary metabolite which is reabsorbed from the intestines. Thus a person with a high fiber diet will excrete a majority of THC [metabolites] in the stool [Anonlj. A fiber-based laxitive will also help by binding bile-acids. Use caution. Fiber laxitives can alter one s bowel schedule and lead to dependancy. 

We (K1) attempted to develop a noncompetitive assay based on the anti-idiotype antibodies for a conjugated bile acid metabolite, ursodeoxycholic acid 7-A-acetyl-glucosaminide (UDCA 7-NAG), which is expected to serve as a diagnostic index for an autoimmune disease, primary biliary cirrhosis. In our assay, the hapten UDCA 7-NAG, a /3-type antibody, and a biotin-labeled a-type antibody were simultaneously added to a microtiter plate coated with an F(ab )2 fragment of a specific anti-UDCA 7-NAG antibody, then incubated at room temperature for 8 h. Bound biotin was then detected with HRP-labeled streptavidin, whose enzyme activity was measured using o-phenylenediamine/H202 as a substrate. This noncompetitive assay system provided a subfemtomole-order sensitivity (detection limit 118 amol) that was 7 times lower than the competitive immunoassay using the same anti-hapten antibody (K2), even with a common colorimetric detection (Fig. 13). Somewhat improved specificity was also obtained namely, better... 

Goto J, Watanabe K, Miura H, Nambara T, Iida T (1987) Trace analysis of bile acids by gas chromatography-mass spectrometry with negative ion chemical ionization detection. J Chro-matogr 388 379-387... 

Kawasaki T, Maeda M, Tsuji A (1983) Immobilized -hydroxysteroid dehydrogenase and dansyl hydrazine as a pre-labeling reagent for high-performance liquid chromatography with fluorescence detection of bile acids. J Chromatogr 272 261-268... 

Bile Acids and Alcohols. Bile acids have been detected in all vertebrates that have been examined and are a result of cholesterol metabolism. The C24 acid, 5(8-cholatiie acid (9) is the structural derivative uf the majority of bile acids in vertebrates. Most mammalian bile acids have a cis-fused A-B ring junction resulting in a nonplanar steroid nucleus. Bile acids, like sterols, typically contain a C3a-hydroxyl group (lithocholic acid 3a-hyroxycholanic acid. 

If bile acid excretion is different, further experiments should be done to determine if bile acid recovery by the intestine or bile acid pool size is changed. The former can initially be assessed by western blot detection of the transporter ASBT. Pool size is... 

Matthees, D.P. and Purdy, W.C., Naphthyldiazomethane as a derivatizing agent for the high-performance liquid chromatography detection of bile acids, Anal. Chim. Acta, 109, 161, 1979. 

Anthony, W.L. and Beher, W.T., Color detection of bile acids using thin layer chromatography,. /. Chromatogr., 13, 570, 1964 Chem. Abs., 60, 13546c, 1964. 

BSEP also known as sister-P-glycoprotein (SPGP) was originally cloned from pig liver (185). BSEP is localized on the canalicular membrane of hepa-tocytes and is responsible for the secretion of bile salts across the canalicular membrane into bile. BSEP appears to be the predominant bile salt efflux system for hepatocytes, and is a critical component in the enterohepatic circulation of bile acids. A number of mutations in the transporter were found to the basis for progressive familial intrahepatic cholestasis type 2 (PFIC2) (186-188). Mutations found in PFIC2 patients include frameshifts, missense mutations, and premature termination codons. Most PFIC2 patients lack immunohistochemically detectable BSEP in their liver. Recently, seven... 

Chemiluminescence is a very sensitive and selective technique. Reagent types, analytes, and detection limits have been summarized in a review by Imai.56 Chemiluminescence has been applied to the analysis of compounds that exhibit low UV absorbance, including metal ions, amino acids, fatty acids, and bile acids. Other detectors include detectors for radioactivity, nuclear magnetic resonance (NMR), and surface-enhanced Raman spectroscopy. Radioactivity detection is one of the most selective detectors, as only components that have been radiolabeled will be detected. The interface of NMR with HPLC and has been discussed in detail by Grenier-Loustalot et al.57 Surface-enhanced Raman spectroscopy is another technique that... 

Separations of complex steroid mixtures were achieved recently by Que et al. [76] using both isocratic and gradient elution. Mass spectrometric detection gave femto-mole detection limits while laser-induced fluorescence of dansylated ketosteroids ranged in attomole levels (Fig. 10.16). Monolithic column packings were used with a 35 cm (25 cm packed bed) x 100 pm i.d. capillary packed with a polymer prepared from 5% T (total monomer concentration), 60% C (total crosslinker concentration), 3% polyethylene glycol, 10% vinylsulfonic acid and 15% lauryl acrylate. Details of the monolithic column preparation can be found in refs. 36,76, and 193. Similar monolithic columns can be used for the separation of bile acids [194],... 

---