Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: C35E7 .10
 63,145 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A high performance liquid chromatography (HPLC) mass spectrometry (MS) system for the analysis of glycine and taurine conjugated bile acids in human fasting and postprandial sera is described. Following purification on thin layer chromatograms conjugated bile acids were separated in a RP-18 5 microns column with methanol 0.02 M KH2PO4 buffer pH 5.10 as the mobile phase at a flow rate of 1 ml/min and assayed by direct injection MS. The bile acid fractions were assayed by MS. The amounts of conjugated bile acids in the postprandial sera of 15 subjects with normal liver function were significantly higher (p less than 0.05) than in fasting ones and the glycine/taurine ratio was about 1 for both. The method is better suited for a specific research area in experiments requiring a high level of accuracy.
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PMID:Analysis of serum conjugated bile acids by high performance liquid chromatography and mass spectrometry. 152 40

A relatively simple and sensitive ion-pair high-performance liquid chromatographic method has been developed for measuring the anticancer drug fluorouracil and its main metabolites, fluorouridine, fluorodeoxyuridine and fluorodeoxyuridine monophosphate in human plasma. A reversed-phase C18 column (150 mm x 2 mm I.D.) and ultraviolet detection (280 nm) were used. The influence of the tetrabutylammonium phosphate and monopotassium phosphate concentrations and pH of the mobile phase on the various k' values was investigated. The optimal k' values obtained for the four compounds ranged between 0.7 and 5.9. The optimized eluent was (10(-4) M tetrabutylammonium phosphate plus 2.10(-2) M potassium dihydrogen phosphate, pH 5.9)-methanol (95.5:4.5, v/v). The flow-rate was 0.3 ml/min. The procedure for plasma preparation included solvent extraction using ethyl acetate-methanol (80:20) followed by elution on C18 Sep-Pak cartridges to separate the four compounds from constituents normally occurring in plasma. The detection limit of the assay was 2 ng/ml (5-fluorouracil), 10 ng/ml (5-fluorouridine), 10 ng/ml (5-fluoro-2'-deoxyuridine) and 50 ng/ml (5-fluoro-2'-deoxyuridine 5'-monophosphate).
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PMID:Determination of 5-fluorouracil and its main metabolites in plasma by high-performance liquid chromatography. 153 12

Fatty acid ethyl ester synthases metabolize ethanol nonoxidatively in those extrahepatic organs most commonly damaged by alcohol abuse. This study was designed to isolate and purify human myocardial synthase-II, one of the enzymes responsible for catalyzing the formation of fatty acid ethyl esters. DEAE-cellulose chromatography of human myocardial cytosol at pH 8.0 separated synthase-I, synthase-II, and synthase-III activities, eluting at conductivities of 5, 7, and 11 mS, respectively. From this elution profile, fatty acid ethyl ester synthase-II accounts for up to 50% of total synthesis in the human heart. This enzyme species was purified over 2200-fold to homogeneity after chromatography over hydroxylapatite, CM-cellulose, and hydroxylapatite. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of this homogeneous species showed a single band at 65 kDa which corresponded to its molecular weight determined by gel filtration. This molecular weight and its lack of glutathione transferase activity indicate that this species is not related to synthase-I and -III. Homogeneous synthase-II has a Vmax for palmitate, stearate, oleate, and linoleate of 70, 80, 140, and 120 nmol/mg/h, respectively. The Km for palmitate, stearate, oleate, and linoleate is 0.19, 0.12, 0.10, and 0.18 mM, respectively. The substrate specificity with respect to alcohol chain length was also investigated in the presence of 0.65 mM [14C]oleic acid. The Vmax for methanol, ethanol, propanol, and butanol was 180, 100, 280, and 410 nmol/mg/h, respectively. The Km for methanol, ethanol, propanol, and butanol was 1.16, 1.04, 0.58, and 0.33 M, respectively. The N-terminal 17-amino acid sequence of human synthase-II does not correspond to any known N-terminal amino acid sequence, indicating that this may be a novel protein. However, it has over 70% homology to a sequence close to the C terminus of rabbit cytochrome P-450IIC1 and over 50% homology to a sequence of human hemopexin starting at residue 16. Synthase-II does not cross-react with human hemopexin antibody and rat cytochrome P-450C antibody. Thus, this study provides evidence that synthase-II is a novel protein, distinct from synthase-I and -III, and it also provides a foundation for subsequent cloning and genetic studies of fatty acid ethyl ester synthase-II in man.
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PMID:Purification and characterization of fatty acid ethyl ester synthase-II from human myocardium. 161 26

A thin-layer chromatographic (TLC) method was developed for the analysis of five sulfonamides [sulfadiazine (SDZ), sulfamerazine (SMRZ), sulfamethazine (SMTZ), sulfadimethoxine (SDMX) and sulfapyridine (SP)] in salmon muscle tissue. "Matrix solid-phase dispersion" was employed whereby the tissue sample was ground with C18-derivatized silica gel. This material was packed into a column and washed with 10% toluene in hexane (discarded) followed by dichloromethane which was evaporated. The residue was chromatographed on a high-performance TLC plate using ethyl acetate-n-butanol-methanol-aqueous ammonia (35:45:15:2, v/v). Sulfonamides were detected after spraying the plate with a solution of fluorescamine. Method parameters were determined by analyzing spiked salmon muscle tissue samples. The method detection limits at the 99% confidence level were 0.11, 0.44, 0.07, 0.13 and 0.13 ppm for SDZ, SMRZ, SMTZ, SDMX and SP, respectively. The lowest-detectable levels were approximately 0.04 ppm for SDZ, SMTZ, SDMX and SP, and 0.10 ppm for SMRZ. The average recoveries of analyses were 61, 63, 60, 63 and 57% for SDZ, SMRZ, SMTZ, SDMX and SP, respectively, and were found to be analyst-dependent. The method was found to give linear detector responses for all analytes over spiking levels ranging from 0 to 2 ppm.
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PMID:Development of a screening method for five sulfonamides in salmon muscle tissue using thin-layer chromatography. 178 30

A reversed phase high performance liquid chromatographic method (RP-HPLC) was developed for the determination of rabbit plasma levels of 1-(p-methylphenyl-2-(2-piperidinoacetyl)-1, 2, 3, 4-tetrahydroisoquinoline hydrochloride (70026), a new antiarrhythmic agent with promising prospects. Its pharmacokinetic parameters were obtained from the rabbit plasma level-time curve measured. 70026 plasma sample was determined by extracting with ether and 0.2 mol/L sulfuric acid, chromatographing on LiChrosorb RP-C18 column, and detecting at 230 nm. The mobile phase selected was methanol-water-triethylamine-phosphoric acid (63:37:1:0.8 v/v). The average recovery of the entire procedure from plasma was 99.94 +/- 3.10 (SD) %; the average CV of within-day and between-day were 4.12% and 3.95% respectively; the minimum detection limit was 3 ng; 70026 plasma concentration ranging from 25-2000 ng/ml yielded a good linear relationship with the peak area ratios, Y = 0. 002865X-0.01346, r = 0. 9999. No endogeneous interference was found in chromatograms of plasma sample. The purity of chromatographic peak of 70026 was identified and proved by mass spectrometry. In urine sample, the hydrolysate of 70026 was found as the original and bound forms. The rabbit plasma level of 70026 after intravenous administration versus time curve was found to be in correspondence with two-compartment model, T1/2 = 4.80 + 1.522 (h).
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PMID:[RP-HPLC determination of 1-(p-methylphenyl-2-(2-piperidinoacetyl- 1,2,3,4-tetrahydroisoquinoline hydrochloride in rabbit plasma and its pharmacokinetic parameters]. 180 21

[Fe3(O)(C7H5O2)6(CH3OH)2(H2O)]-[C7H5O2]-C2H5OH-CH3OH (1/1/1), Mr = 1191.56, triclinic, P1-, a = 11.591 (3), b = 13.308 (2), c = 20.154 (3) A, alpha = 96.910 (12), beta = 96.95 (2), gamma = 114.10 (2) degrees, V = 2767.1 (9) A3, Z = 2, Dx = 1.43 g cm-3, mu = 8.471 cm-1, Mo K alpha radiation, lambda = 0.7107 A, F(000) = 1234, T = 198 K, R = 0.0522 for 6252 reflections [Fo greater than or equal to 4 sigma (Fo)]. The complex has nearly D3h symmetry with two coordinated CH3OH molecules and one coordinated H2O molecule. The coordination around the Fe atoms is essentially octahedral. Each Fe atom lies slightly out of the plane of the O atoms of the bridging benzoates and is directed towards the mu 3-O atom. The average Fe--O distances are 1.907 (2) A for the mu 3-O atom and 2.010 (1) A for the benzoate O atoms.
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PMID:Structure of aqua-hexakis(mu 2-benzoato)-bis(methanol)-mu 3-oxo-triiron(III) benzoate ethanol methanol solvate. 186 27

Taxol, a novel antimitotic, antitumor agent is currently undergoing Phase 1 clinical trials for the treatment of various tumors. An isocratic HPLC method has been developed for the determination of taxol in human plasma and urine. The method was then applied to the clinical pharmacokinetics of taxol following 6-h intravenous (i.v.) infusions at doses of 175 and 225 mg m-2. A mobile phase of methanol-acetate buffer (0.02 M, pH 4.5) (65:35, v/v) was used to elute a C8 column with detection at 227 nm. The sample preparation involved extraction with t-butyl methyl ether followed by further clean-up of the sample by solid-phase extraction. The method was linear from 0.10-10 microM injected, with a chromatographic run time of 6 min. The results obtained from the clinical study indicate that the plasma pharmacokinetics of taxol are best characterized by a two compartment open body model. Additionally, the present study resulted in the detection of a previously unreported peak which may be a metabolite of taxol.
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PMID:Analysis of anticancer drugs in biological fluids: determination of taxol with application to clinical pharmacokinetics. 198 32

Groups of male Fischer F344 rats isocalorically consuming cooked, low-fat human diets were given magnetic polyethyleneimine (PEI) microcapsules and [14C]benzo[a]pyrene (B[a]P) by gavage in order to determine the effects of 3-fold changes in levels of dietary fibre non-starch polysaccharide (NSP) and beef protein during gastrointestinal transit on microcapsule trapping and associated parameters. Total 14C trapped by microcapsules during 70 h was decreased by fibre and increased by beef with significant effects (P = 0.03) for dietary mass ratio beef/fibre and compared to controls eating chow. Total B[a]P excreted in faeces and the ration for faeces/urine were increased by fibre and not by beef; the distribution of B[a]P metabolites between liquid and solids of faeces was increased by both factors but there was a net decrease by fibre when allowing for its influence on faecal mass. The distribution of binding between microcapsules and faecal solids was increased significantly by beef, but fibre had no effect when mass-normalized. B[a]P metabolites were extracted from microcapsules by methanol-ammonia and HPLC assay showed mainly benzo[a]pyrene-3,6-dione (B[a]P 3,6-dione), benzo[a]pyrene-1,6-dione (B[a]P 1,6-dione), an unidentified metabolite and substances consistent with tetraols; the beef (P = 0.02) and beef/fibre ratio (P = 0.01) significantly increased B[a]P-1,6-dione trapped and released. In vitro, B[a]P 3,6-semidione (dione reduced form) was bound by PEI microcapsules; the extent of extraction/hydrolysis was much lower than for B[a]P e,6-dione or B[a]P 7,8-diol 9.10-epoxide. Urinary excretion of B[a]P metabolites was decreased by fibre but not by beef. Nearly all the above parameters were different in a control group consuming rat chow. Taken together, these results are consistent with the following conclusions; (i) dietary fibre NSP overall decreases the availability of B[a]P metabolites to contact microcapsules and intestinal mucosa through static bulking rather than absorption; (ii) beef protein increases binding to microcapsules, and enhances free radical activation of B[a]P to its 6-yl radical form; (iii) a systematic set of concordant relationships for B[a]P disposition were found between faecal solids, faecal liquids, microcapsules and urine; and (iv) rat chow produced effects quite unrepresentative of the range for human diets prepared to be in the norm for human use. Endogenous UV-absorbing substances trapped by microcapsules or excreted in urine were also altered by dietary beef levels and were different from those of chow-consuming animals. It is generally concluded that human diets can and should be used in studying carcinogen metabolism and disposition.
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PMID:Systematic modulation by human diet levels of dietary fibre and beef on metabolism and disposition of benzo[a]pyrene in the gastrointestinal tract of Fischer F344 rats. 215 57

An enzymatic assay method for the determination of urinary formic acid is described. Formic acid in urine was cleaved to carbon dioxide and water by formic acid dehydrogenase, whereby NAD+ was converted to NADH, which reacted with INT (p-iodonitrotetrazolium violet) in the presence of NAD-diaphorase. The color thus produced was determined at 500 nm. In addition, a simple gas chromatographic method of urinary formic acid is described, in which head space gas of formic acid methylester was applied into the wide bore column. The urinary formic acid concentrations by the enzymatic method agreed well with that by the gas chromatographic method. A simple gas chromatographic method for urinary methanol assay is also described. Acetonitrile was added to an equal volume of urine containing methanol. After centrifugation, the supernatant was injected into gas chromatography (GC). The peaks of urinary methanol and ethanol were separated by GC. Formic acid and methanol in urine of unexposed healthy subjects and workers exposed to methanol were analyzed by the colorimetric and gas chromatographic methods. Geometric mean concentrations of urinary formic acid and methanol in the healthy subjects were 7.82 mg/g creatinine and 1.34 mg/l, respectively. The concentration ratio of formic acid to methanol in the urine of the workers exposed to methanol was calculated to be 3.67 +/- 2.10, which agreed with the ratio under a controlled exposure experiment. A slower excretion of formic acid than that of methanol in the urine of a volunteer was also observed.
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PMID:Enzymatic assay of formic acid and gas chromatography of methanol for urinary biological monitoring of exposure to methanol. 234 46

Although the peptide Boc-Aib1-Ala2-Leu3-Aib4-Ala5-Leu6-Aib7-Ala8-L eu9-Aib10-OME [with a t-butoxycarbonyl (Boc) blocking group at the amino terminus, a methyl ester (OMe) at the carboxyl terminus, and four alpha-amino-isobutyric (Aib) residues] has a 3-fold repeat of residues, the helix formed by the peptide backbone is irregular. The carboxyl-terminal half assumes an alpha-helical form with torsion angles phi and psi of approximately -60 degrees and -45 degrees, respectively, whereas the amino-terminal half is distorted by an insertion of a water molecule between the amide nitrogen of Ala5 [N(5)] and the carbonyl oxygen of Ala2 [O(2)]. The water molecule W(1) acts as a bridge by forming hydrogen bonds N(5)...W(1) (2.93 A) and W(1)...O(2) (2.86 A). The distortion of the helix exposes the carbonyl oxygens of Aib1 and Aib4 to the outside environment, with the consequence that the helix assumes an amphiphilic character despite having all apolar residues. Neighboring helices in the crystal run in antiparallel directions. On one side of a helix there are only hydrophobic contacts with efficient interdigitation of leucine side chains with those from the neighboring helix. On the other side of the helix there are hydrogen bonds between protruding carbonyl oxygens and four water molecules that separate two neighboring helices. Along the helix axis the helices bind head-to-tail with a direct hydrogen bond N(2)...O(9) (3.00 A). Crystals grown from methanol/water solution are in space group P21 with a = 15.778 +/- 0.004 A, b = 11.228 +/- 0.002 A, c = 18.415 +/- 0.003 A, beta = 102.10 +/- 0.02 degrees, and two formula units per cell for C49H88N10O13.2H2O.CH3OH. The overall agreement factor R is 7.5% for 3394 reflections observed with intensities greater than 3 sigma (F), and the resolution is 0.90 A.
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PMID:Aqueous channels within apolar peptide aggregates: solvated helix of the alpha-aminoisobutyric acid (Aib)-containing peptide Boc-(Aib-Ala-Leu)3-Aib-OMe.2H2O.CH3OH in crystals. 244 72


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