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At least 1,477 records · Page 82Linked to original sources
PubMed1990

Antianoxic action and active constituents of atractylodis lanceae rhizoma.

The screening test was carried out to identify new drugs from natural products for the KCN-induced anoxia model in mice. Acetone extract of Atractylodis Lanceae Rhizoma (Atractylodes lancea DC. var. Chinensis Kitamura) had a significant effect in the KCN-induced anoxia model and therefore the extract was selected for further study in order to identify the active principles. The result showed that beta-eudesmol was the active component in Atractylodis Lanceae Rhizoma.

Animals↗
PubMed2003

[Experimental study on selecting optimal time of orthodontic tooth movement into extraction sites].

OBJECTIVE: The purpose of this study was to investigate the physiological process of healing after tooth extraction and the biological reaction of tooth movement into extraction sites with the aim of selecting optimal time of tooth movement into extraction sites clinically. METHODS: Extraction of upper first molars were performed on 30 male Sprague-Dawley rats which were divided equally into 5 groups. Orthodontic appliance was placed at different time after tooth extraction in order to move the maxillary second molars mesially into the extraction spaces. The animals were injected continuously with tetracycline and calcein for two days before appliance activation and animal sacrifice. Undecalcified mesio-distal specimans 65-100 microns of thickness were prepared. The quantification of bone remodeling parameters on tooth movement into extraction sites at different time was performed by histomorphometric measurements and computer image analysis. RESULTS: 1. The bone turnover had two bone modeling processes: resorption under pressure and formation in tension. 2. The bone resorption was more active on the mesial surface (pressure side) than that on the distal surface (tension side). While bone formation was more active on the distal surface (tension side) than that on the mesial surface (pressure side). 3. Both the resorptive parameters and the formative parameters across time were manifested by a peak at day 7 after tooth extraction. CONCLUSION: 1. Orthodontic retraction into extraction sites should be initiated at an early stage after tooth extraction, so that the advantage of bone remodeling in extraction sites was used. 2. The optimal time of tooth movement into extraction sites clinically was about a week after tooth extraction.

Animals↗
PubMed2002

Chloroform extract of Carica papaya seeds induces long-term reversible azoospermia in langur monkey.

AIM: To evaluate the antifertility activity of the chloroform extract of Carica papaya seeds by oral administration in langur monkey, Presbytis entellus entellus. METHODS: The chloroform extract of Carica papaya seeds, 50 mg/kg/day, was administered orally for 360 days to adult male langur monkeys. The sperm characteristics by light and electron microscopy, the sperm functional tests, the semen biochemistry, the serum testosterone level, the Leydig cell function, and the histology and ultrastructure of testis were determined to evaluate the antifertility activity and the blood biochemistry and hematology, to evaluate the toxicology. RESULTS: The extract gradually decreased the sperm concentration since days 30-60 of treatment with a total inhibition of sperm motility, a decrease in sperm viability and increase in sperm abnormality. Azoospermia was observed after day 90 of treatment and continued during the whole treatment period. Treatment withdrawal resulted in a gradual recovery in these parameters and 150 days later they reverted to nearly the pretreatment values. Morphological observation of the ejaculated sperm by light and scanning electron microscopy showed deleterious changes, particularly on the mid-piece. Sperm functional tests, viz., sperm mitochondrial activity index, acrosome intactness test and hypo-osmotic swelling test scored in the infertile range during treatment and returned to the fertile values 150 days after drug withdrawal. Histology of the testis revealed shrunken tubules, germ cell atrophy and normal Leydig cells. Ultrastructure of the testis showed vacuolization in the cytoplasm of Sertoli cells and germ cells. Loss of cytoplasmic organelles were evident in the spermatocytes and spermatids. Round spermatids showed loss of Golgi bodies, peripheral mitochondria and vacuolated cytoplasm, indicating maturational arrest. Leydig cell functional test indicated a mild inhibition of steroidogenic function. Haematology and serum biochemistry study disclosed no significant toxicological effect and the serum testosterone level was not affected. CONCLUSION: Carica papaya seed extract may selectively act on the developing germ cells, possibly mediated via Sertoli cells, leading to azoospermia.

Animals↗
PubMed1992

DNA typing of isolates associated with the 1988 sporotrichosis epidemic.

DNA typing techniques were used to examine selected clinical and environmental isolates of Sporothorix spp. recovered from the 1988 sporotrichosis epidemic in multiple states of the United States. Previous studies indicated that isolates in one of the six morphologically or physiologically distinct groups (group I) obtained from environmental sources were Sporothrix schenckii and were the possible etiologic agents responsible for the epidemic. To assess this hypothesis at the genetic level, whole-cell DNA was extracted from selected clinical isolates and representative members of each of the six environmental groups subjected to endonuclease digestion and then analyzed by gel electrophresis. DNA types were assigned on the basis of restriction fragment length polymorphism patterns. One DNA type was common to clinical and group I isolates but was dissimilar from the DNA types exhibited by groups II to VI. In contrast, a variety of DNA types were associated with isolates in groups II to VI. The latter groups appeared to make up a heterogeneous collection of fungi, with some members of the same group having different DNA types but with others from different groups possessing identical DNA types. Thus, DNA typing studies confirmed that group I environmental isolates are indistinguishable from clinical isolates and that group II to VI isolates represent a complex of related fungi with similar Sporothrix anamorphs.

DNA, Fungal↗
PubMed2006

Rapid and simultaneous determination of nonsteroidal anti-inflammatory drugs in human plasma by LC-MS with solid-phase extraction.

A rapid, selective and sensitive analytical method for the simultaneous determination of 16 nonsteroidal anti-inflammatory drugs (NSAIDs) in human plasma was carried out using Oasis HLB solid-phase extraction (SPE), followed by reversed-phase high-performance liquid chromatography and quadrupole mass spectrometry with electrospray ionization operated in the negative ion mode. The recoveries of NSAIDs from human plasma by SPE were greater than 76.7%. The use of a short column packed with small particles enabled rapid and simultaneous determination within 7 min. The detection limits for the NSAIDs were 0.01-0.9 mug/ml using the selected ion monitoring mode.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2005

Antiinflammatory and immunomodulating properties of fungal metabolites.

We discuss current information on the ability of extracts and isolated metabolites from mushrooms to modulate immune responses. This can result in a more enhanced innate and acquired disease resistance. The major immunomodulating effects of these active substances derived from mushrooms include mitogenicity and activation of immune effector cells, such as lymphocytes, macrophages, and natural killer cells, resulting in the production of cytokines, including interleukins (ILs), tumor necrosis factor alpha (TNF)-alpha, and interferon gamma (INF)-gamma. In particular, the ability of selective mushroom extracts to modulate the differentiation capacity of CD4(+) T cells to mature into T(H)1 and/or T(H)2 subsets will be discussed. As a consequence these extracts will have profound effects in particular diseases, like chronic autoimmune T(H)1-mediated or allergic T(H)2-mediated diseases. Immunosuppressive effects by mushroom components have also been observed. The therapeutic effects of mushrooms, such as anticancer activity, suppression of autoimmune diseases, and allergy have been associated with their immunomodulating effects. However, further studies are needed to determine the molecular mechanisms of the immunomodulating effects of mushrooms metabolites both individually and in complex mixtures, for example, extracts.

Agaricales↗
PubMedDate not supplied

Long-term surgical results of combined trabeculotomy ab externo and cataract extraction.

Trabeculotomy ab externo has been demonstrated to be effective in controlling intraocular pressure (IOP) in adult patients with either primary open-angle glaucoma or pseudoexfoliation syndrome. We evaluated the surgical outcome of 60 eyes with either primary open-angle glaucoma or pseudoexfoliation syndrome that underwent combined trabeculotomy ab externo and cataract extraction. All patients were at least 40 years old, and were followed for at least 1 year. At the final examination, IOP was well controlled (21 mm Hg or less) in 54 (90%) of the 60 eyes, with or without medication. Also, "overall success" (ie, stabilization of IOP, visual field, and optic nerve status) was achieved in 49 (81.7%). Complications included fibrin exudation (22%), transient IOP elevation (17%), early perforation of the probe into the anterior chamber (10%), and detachment of Descemet's membrane (5%). We recommend combined trabeculotomy ab externo and cataract extraction in selected cases of glaucoma with coexisting cataract. For cases in which the target IOP level is in the low teens, or for patients who may not tolerate postoperative fluctuations in IOP, we do not recommend trabeculotomy ab externo. Also, in eyes that have normal-tension glaucoma, or that have already sustained severe damage to the optic nerve, visual dysfunction caused by glaucomatous changes may progress even after successful combined trabeculotomy ab externo and cataract extraction.

Aged↗
PubMed1998

Successful immunotherapy. A partnership between consultant and general practitioner.

BACKGROUND: Allergen-specific immunotherapy has been used to treat allergic patients for many decades. Numerous clinical trials have demonstrated its efficacy in patients with seasonal allergic rhinitis, perennial allergic rhinitis, stinging insect allergy and allergic asthma. OBJECTIVE: This article discusses antigen specific immunotherapy and outlines the conditions that respond well to it. DISCUSSION: Immunotherapy has the potential to cause immediate systemic reactions which rarely may result in fatal anaphylaxis. Therefore, only practitioners with appropriate training and expertise should make the decision to prescribe immunotherapy based on careful patient selection and extract prescription. Patients receiving this therapy require supervision in a setting with the necessary resuscitation equipment by a practitioner with the skills to recognise and treat adverse events.

Allergens↗
PubMed2001

Rapid, high-throughput extraction of bacterial genomic DNA from selective-enrichment culture media.

AIMS: To create a fast, sensitive and inexpensive high-throughput method for the extraction of bacterial genomic DNA from selective-enrichment culture media. METHODS AND RESULTS: Lysis of bacteria was achieved using guanidinium isothiocyanate, and DNA was extracted using 96-well glass microfibre filtration plates. Extraction-PCR detected the presence of 1 cfu Yersinia ruckeri and 16 cfu Lactococcus garvieae 200 microl(-1) sample of selective-enrichment medium. CONCLUSION: An efficient method for high-throughput extraction of bacterial genomic DNA from selective-enrichment culture media was achieved. SIGNIFICANCE AND IMPACT OF THE STUDY: This method enables detection of covert bacterial infections in fish. The simultaneous extraction of large numbers of samples allows for its use in bacterial monitoring programmes and quarantine.

Bacteria↗
PubMed2001

Determination of total and EDTA extractable metal distributions in the colloidal fraction of contaminated soils using SdFFF-ICP-HRMS.

Newly developed methods involving an on-line combination of sedimentation field-flow fractionation-inductively coupled plasma-high resolution mass spectrometry (SdFFF-ICP-HRMS) have been used to study the distributions of extractable heavy metals in a soil which had been treated with sewage sludge contaminated with Cu or Pb. The relationship of these metals with other elements in the colloidal fraction was also investigated. The colloidal fraction from the soil was obtained by repeated gravitational sedimentation and extracted with 0.11 M acetic acid, 0.1 M hydroxylamine hydrochloride, 0.05 M ethylenediaminetetraacetic acid disodium salt (EDTA) or aqua regia to assess the potential availability of the metals Cu and Pb. Large proportions of the Cu and Pb were extracted by EDTA, approaching that removed by aqua regia, whereas < 10% of the aqua regia extractable metals were removed by acetic acid and hydroxylamine chloride. The distributions of the heavy metals, the major mineral forming element (Al) and the elements forming sesquioxides (Fe and Mn) within different size classes (0.05-1 microm) of the colloidal fraction were measured using SdFFF-ICP-HRMS before and after extraction with EDTA. This information provides an insight into the composition of the colloids and the distributions of metal contaminants. In the contaminated soil colloids, the concentration of Fe, Mn and Pb is greatest in the smaller particles (<0.2 microm). In contrast, the Cu concentration is constant over the size range studied. Iron oxide surface coatings probably play a significant role in Pb adsorption on soil particles, but may be less important for Cu. The combination of selective chemical extraction, SdFFF and ICP-HRMS provides a means of determining the distribution of potentially available heavy metals within the colloidal fraction of contaminated soils.

Chelating Agents↗
PubMed1982

Analytic clinical laboratory precision. State of the art for selected enzymes.

Results of precision estimates are reported for selected enzyme analytes. Laboratories that participated in regional quality control programs supplied data to a centralized data processing service (College of American Pathologists Computer Center). These data, representing several regional groups which used different commercial sources of control serum, were statistically analyzed by regression of coefficient of variation (CV) upon concentration of analyte using a modified polynomial regression technic. Tolerance limits for long-term within-laboratory precision were developed from this data. Estimated CVs were extracted at selected analyte concentrations, and tolerance limits for CVs at these concentrations were developed. In addition, selected individual methods within the larger groups were individually examined to evaluate effect of control material matrix upon clinical estimates of enzyme precision. Differences in selected method groups are discussed.

Alanine Transaminase↗
PubMedDate not supplied

Effect of lipid extraction methods on total dietary fiber and nonstarch polysaccharide contents of selected nuts and seeds.

Three extraction methods were used to remove lipid materials from 8 edible nuts and seeds before analysis for their total dietary fiber (TDF) and nonstarch polysaccharide (NSP) contents. Portions of ground materials were extracted by: n-hexane, followed by 80% methanol, n-hexane-acetic acid (95 + 5, v/v), and supercritical carbon dioxide. Defatted samples were gelatinized in water and incubated with amyloglucosidase; 95% ethanol was added to the hydrolyzates, and the residues were collected on tared glass crucibles. TDF was calculated according to a simplified enzymatic-gravimetric method developed in our laboratory, and NSP was determined as described by Englyst and coworkers. Dietary fiber values obtained with any of the extraction methods range from 3.47 g/100 g for cashews to 28.56 g/100 g for sunflower seeds. Nonstarch polysaccharide values range from 2.43 g/100 g for pecans to 5.56 g/100 g for peanuts. With the exception of sunflower seeds, samples extracted with supercritical carbon dioxide had lower TDF contents but similar amounts of NSP compared with samples extracted by the other 2 methods.

Acetic Acid↗
PubMed2004

Management of fibromyalgia syndrome.

CONTEXT: The optimal management of fibromyalgia syndrome (FMS) is unclear and comprehensive evidence-based guidelines have not been reported. OBJECTIVE: To provide up-to-date evidence-based guidelines for the optimal treatment of FMS. DATA SOURCES, SELECTION, AND EXTRACTION: A search of all human trials (randomized controlled trials and meta-analyses of randomized controlled trials) of FMS was made using Cochrane Collaboration Reviews (1993-2004), MEDLINE (1966-2004), CINAHL (1982-2004), EMBASE (1988-2004), PubMed (1966-2004), Healthstar (1975-2000), Current Contents (2000-2004), Web of Science (1980-2004), PsychInfo (1887-2004), and Science Citation Indexes (1996-2004). The literature review was performed by an interdisciplinary panel, composed of 13 experts in various pain management disciplines, selected by the American Pain Society (APS), and supplemented by selected literature reviews by APS staff members and the Utah Drug Information Service. A total of 505 articles were reviewed. DATA SYNTHESIS: There are major limitations to the FMS literature, with many treatment trials compromised by short duration and lack of masking. There are no medical therapies that have been specifically approved by the US Food and Drug Administration for management of FMS. Nonetheless, current evidence suggests efficacy of low-dose tricyclic antidepressants, cardiovascular exercise, cognitive behavioral therapy, and patient education. A number of other commonly used FMS therapies, such as trigger point injections, have not been adequately evaluated. CONCLUSIONS: Despite the chronicity and complexity of FMS, there are pharmacological and nonpharmacological interventions available that have clinical benefit. Based on current evidence, a stepwise program emphasizing education, certain medications, exercise, cognitive therapy, or all 4 should be recommended.

Analgesics↗
PubMed2005

Efficient analysis and extraction of MS/MS result data from Mascot result files.

BACKGROUND: Mascot is a commonly used protein identification program for MS as well as for tandem MS data. When analyzing huge shotgun proteomics datasets with Mascot's native tools, limits of computing resources are easily reached. Up to now no application has been available as open source that is capable of converting the full content of Mascot result files from the original MIME format into a database-compatible tabular format, allowing direct import into database management systems and efficient handling of huge datasets analyzed by Mascot. RESULTS: A program called mres2x is presented, which reads Mascot result files, analyzes them and extracts either selected or all information in order to store it in a single file or multiple files in formats which are easier to handle downstream of Mascot. It generates different output formats. The output of mres2x in tab format is especially designed for direct high-performance import into relational database management systems using native tools of these systems. Having the data available in database management systems allows complex queries and extensive analysis. In addition, the original peak lists can be extracted in DTA format suitable for protein identification using the Sequest program, and the Mascot files can be split, preserving the original data format. During conversion, several consistency checks are performed. mres2x is designed to provide high throughput processing combined with the possibility to be driven by other computer programs. The source code including supplement material and precompiled binaries is available via http://www.protein-ms.de and http://sourceforge.net/projects/protms/. CONCLUSION: The database upload allows regrouping of the MS/MS results using a database management system and complex analyzing queries using SQL without the need to run new Mascot searches when changing grouping parameters.

Databases, Factual↗
PubMed1992

Identification of cell-surface heparin/heparan sulfate-binding proteins of a human uterine epithelial cell line (RL95).

The interaction of heparin (HP) with the cell-surface components of a human uterine epithelial carcinoma cell line (RL95) was studied. Binding of [3H]HP to cell surfaces was saturable in a dose- and time-dependent manner. HP and certain forms of heparan sulfate (HS) efficiently compete for [3H]HP binding. In contrast, other glycosaminoglycans, such as chondroitin sulfate, keratan sulfate, hyaluronic acid, and dermatan sulfate, do not compete for binding to these sites. Scatchard analysis revealed that [3H]HP bound to these sites with an apparent KD of 0.7-0.9 microM and a binding capacity of 9 x 10(6) sites/cell to attached cells. EDTA-detached cells displayed a similar apparent KD, but an approximately 2-fold increase in binding capacity. Protease digestion of cells on ice markedly reduced [3H]HP binding, indicating that these binding sites were associated with proteins. In contrast, heparinase treatment of cells stimulated binding by approximately 2-fold, indicating that a large fraction of these binding sites were occupied with endogenous ligand. We examined the structural features of HP/HS required for HP/HS binding. O-Sulfation, substitution of amino groups, and, to a lesser extent, the presence of carboxyl groups were important recognition features of HP/HS by cell-surface HP/HS-binding sites. N-Sulfation was not required. Photoaffinity labeling with 125I-sulfosuccinimidyl 2-(p-azidosalicylamido)-ethyl-1, 3-dithiopropionate-HP was used to identify HP/HS-binding proteins on RL95 cell surfaces. Proteins with M(r) values of 14,000-18,500 and 31,000 were photolabeled at the surfaces of attached cells. Photolabeling was blocked by the addition of excess HP, but not chondroitin sulfate. Additional proteins with M(r) values greater than 31,000 were photolabeled specifically on EDTA-detached cells. Moreover, the M(r) 14,000-18,500 and 31,000 proteins were retained on the EDTA-detached cells. These observations indicated that certain cell-surface HP/HS-binding proteins were not exposed when cells were attached to substrata. Proteins of similar M(r) values as the photolabeled components as well as many additional proteins were identified by heparin-agarose chromatographic selection of extracts of cells labeled metabolically with [35S]methionine or vectorially with Na125I at the cell surface. Fragments of cell-surface HP/HS-binding proteins were released from intact RL95 and mouse uterine epithelial cells by mild trypsinization and isolated by heparin-agarose affinity chromatography. Three peptides with M(r) values between 6000 and 14,000 required greater than 0.5 M salt for elution from heparin-agarose, retained HP binding activity in a 125I-HP gel overlay assay, and selectively bound [3H]HP in a solid-phase binding assay.(ABSTRACT TRUNCATED AT 400 WORDS)

Affinity Labels↗
PubMed2004

Selective determination of trimethylamine in air by liquid chromatography using solid phase extraction cartridges for sampling.

The selective determination of trimethylamine (TMA) in air by liquid chromatography is reported. Sampling is effected by flushing air through C18-packed solid-phase extraction (SPE) cartridges at a flow rate of 15 mL/min for 15 min. Next, TMA is desorbed from the cartridges and injected into the chromatographic system. The analyte is then selectively retained on a precolumn (20 mm x 2.1 mm i.d., packed with 30 microm, Hypersil C18 phase), and derivatized on-line by injecting 9-fluorenylmethyl chloroformate (FMOC). Finally, the TMA-FMOC derivative is transferred to the analytical column (125 mm x 4 mm i.d., LiChrospher 100 RP18, 5 microm), and monitored at 262 nm. The method was applied to the measurement of TMA in air in the 0.25-2.5 microg interval (equivalent to concentrations of TMA of 1.1-11 mg/m3), providing good linearity, reproducibility and accuracy. The mean recovery of TMA was (96 +/- 7%) (n = 12), and the limit of detection was 0.05 microg. The proposed procedure allows the selective determination of TMA in the presence of other primary and secondary short-chain aliphatic amines.

Air Pollutants, Occupational↗
PubMed2005

Endocrine disruption of water and sediment extracts in a non-radioactive dot blot/RNAse protection-assay using isolated hepatocytes of rainbow trout.

GOAL, SCOPE AND BACKGROUND: In order to evaluate the estrogenic activity of sediments and XAD water extracts of selected sites of the catchment area of the River Neckar, a river system in Southern Germany, an integrative assessment approach was used to assess the ecological hazard potential of endocrine-disrupting compounds in sediment and water. METHODS: The approach is based on estrogen receptor-mediated vitellogenin synthesis induced in isolated hepatocytes of rainbow trout and quantified in a non-radioactive dot blot/RNAse protection-assay in parallel to comprehensive chemical analyses of estrogenic substances. RESULTS AND DISCUSSION: Numerous investigated extracts revealed an estrogen activity comparable to that of the positive control (1 nM 17beta-estradiol corresponding to 270 ng/L in the test medium). Based on a concentration factor of 30 in the extracts and a recovery of XAD resins of approximately 80%, 17beta-estradiol equivalent concentrations between 20 and 26.7 ng/L could be calculated downstream of a sewage treatment plant (< 0.1 ng/L for a reference site). A comparison of the bioassay-derived Bio-TEQs (toxicity equivalents) and the Chem-TEQs revealed a high correlation with a Pearson coefficient of 0.85, indicating that the same ranking of the samples could be obtained with respect to the endocrine disrupting potential with both chemical and bioanalytical analysis. However, the TEQ concentrations computed from chemical analyses were significantly lower than the bioassay-derived TEQ concentrations. In fact, in none of the samples, more than 14% of the vitellogenin-inducing potency could be attributed to the substances (steroids, alkylphenols, bisphenol A, diethylstilbestrol) analyzed. A comparison of the endocrine disrupting potential of sediments extracted by the solvents acetone and methanol revealed lower biological effects for acetone-extracted samples. Possible reasons may be a masking of endocrine effects in acetone extracts by cytotoxicity, a low extraction efficiency of the solvent acetone, or anti- estrogen potencies of some extracted sediment compounds. Using a mass balance approach, the contribution of the compounds analyzed chemically (Chem-TEQs) to the total endocrine activity (Bio-TEQs) was calculated. Based on the very low detection limits, particularly of the steroids with their high TEF factors, results revealed that a calculation of the Chem-TEQs is associated with considerable scale inaccuracy: Whereas only 7-15% of the biological effectiveness (Bio-TEQs) could be explained by endocrine substances identified above the detection limits, the assumption of concentrations slightly below the given detection limits would result in a significant over estimation (137-197%) of the Bio-TEQs. Even the interassay variation of the dot blot assay with different fish donors for primary hepatocyte (factor 2-2.5) is relatively low, when compared to the large range of the Chem-TEQ concentrations (factor 20) obtained when applying different modes of calculation. CONCLUSIONS AND OUTLOOK: Overall, only a minor portion of the endocrine activity detected by bioassays could be linked to compounds identified by chemical analysis. In vitro assays for assessment of endocrine activities are useful as sensitive integrating methods that provide quantitative estimates of the total activity of particular receptor-mediated responses. Although discrepancies may also result from different bioanalytical approaches, it is overall likely that bioanalytical and not chemical analytical approaches give the correct estimate of endocrine disrupting potencies in environmental samples. As a conclusion, assessment of endocrine disruption based on chemical analysis alone does not appear sufficient and further research into the spectrum of substances with potential endocrine activity as well as into additive or even synergistic effects in complex environmental samples is urgently needed.

Acrylic Resins↗
PubMed1990

[75Se]-selenohomotaurocholic acid degradation by bacterial enzymes in vitro and in vivo. Is it still a specific indicator for active ileal bile acid uptake?

The stability of the bile acid analogue [75Se]-selenohomotaurocholic acid (75SeH-CAT) was studied in man. When 75SeHCAT was administered to patients for diagnostic purposes the majority of labeled material present in the feces was found deconjugated. In vitro incubation of 75SeHCAT, by addition of fecal homogenate or with addition of purified enzyme, showed identical deconjugation. The relative differences in polarities of 75SeHCAT, [75Se]-selenohomocholic acid (75SeHCA), [14C]-taurocholic acid (14C-TCA) and [14C]-cholic acid (14C-CA) were estimated by isoelectric focusing and selective chloroform extractions at various pH values. The pI values representing the pH where these molecules become uncharged were for 75SeHCA and 75SeHCAT 3.1, for 14C-TCA 3.0 and for 14C-CA 3.9. These results suggest that from these bile acids only 14C-CA is a candidate for passive absorption in the colon, while 75SeHCA would be far too polar for passive diffusion. Indeed, we could demonstrate the inability of 75SeHCA for passive absorption in healthy persons. In conclusion, 75SeHCAT, specifically selected to monitor active ileal bile acid transport, functions as a good indicator of this process in its conjugated form. In contrast to published data it is susceptible to bacterial degradation, and therefore gives rise to a diminished whole-body retention.

Amidohydrolases↗