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Results 401 - 450 of 1377
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Phelps Craig D - - 2002
During the anaerobic biodegradation of naphthalene and methylnaphthalene, unique metabolites are formed by specific microbial carboxylation and ring-reduction reactions. Groundwater samples from an anoxic, shallow aquifer contaminated with gasoline were examined for the presence of these metabolites by extraction, derivatization and gas chromatography coupled to mass spectroscopy. Several metabolites [2-naphthoic ...
Wiwanitkit Viroj - - 2002
Toluene is an important toxic volatile agent found in many modern industrial processes. Toluene exposure is of particular concern because of the ongoing exposure of thousands of workers in industrial plants and recent research has indicated that toluene/exposure can result in chronic toxicity. The monitoring and control of toluene exposure ...
Mutlib Abdul E - - 2002
The in vivo and in vitro disposition of benzylamine was investigated in rats. Benzylamine was metabolized to only a small extent by rat liver subcellular fractions. In contrast, it was extensively metabolized in vivo in rats. In vivo studies performed with stable isotope-labeled benzylamine enabled rapid mass spectrometric identification of ...
Stillwell Matthew E - - 2002
The first case involving an alleged sexual assault linked to the use of gamma-hydroxybutyric acid (GHB) in Oklahoma is reported. A-48-year-old Caucasian woman taking amitriptyline was known to have voluntarily ingested a sports drink containing a relaxing health product. She purportedly experienced unconsciousness that persisted for approximately 4 h. The ...
Yamamoto Tetsuya - - 2002
OBJECTIVE: To develop a simple means of selecting gout patients for treatment with uricosuric agents. METHODS: In 124 gout patients, spot urine and blood were sampled before breakfast and after overnight fast (except water) on the day of 24 h urine collection. Spot urine uric acid/creatinine ratio (Ua/Cr mmol/mmol) and ...
Laube Norbert - - 2002
In order to distinguish between normocitraturia and hypocitraturia, the 24 h urine excretion value of citric acid is evaluated in relation to the established limit value of 2.5 mmol/day. We propose changing this widely-used excretion value to a "minimum contribution" of citric acid to the total urine's ionic strength, since ...
Namera Akira - - 2002
The purpose of this study was to develop a simple and accurate analytical method to determine amino acids in urine samples. The developed method involves the employment of an extract derivatization technique together with gas chromatography-mass spectrometry (GC-MS). Urine samples (300 microl) and an internal standard (10 microl) were placed ...
Manini Paola - - 2002
Two workers were accidentally exposed to unusually high styrene concentrations (>1000 ppm) for about 30 min. In addition to the main styrene metabolites, mandelic acid (MA) and phenylglyoxylic acid (PGA), other minor metabolites, including specific mercapturic acids, (R,R)- and (S,R)-N-acetyl-S-(1-phenyl-2-hydroxyethyl)-L-cysteine [(R,R)-M1 and (S,R)-M1] and (R,R)- and (S,R)-N-acetyl-S-(2-phenyl-2-hydroxyethyl)-L-cysteine [(R,R)-M2 and (S,R)-M2], ...
Sjöquist Birgitta - - 2002
The ocular pharmacokinetics of latanoprost (13,14-dihydro-17-phenyl-18, 19,20-trinor-PGF(2alpha)-isopropyl ester; Xalatan [Pharmacia-Upjohn, Peapack, NJ]) was studied in patients undergoing cataract surgery using radio-immunoassay, and the systemic pharmacokinetics of latanoprost was studied in healthy human volunteers with 3H-latanoprost as well as radioimmunoassay. After topical application, latanoprost was rapidly hydrolysed in the cornea and ...
Noguchi Toshiya - - 2002
We have developed esonarimod, (+/-)-2-acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid, as a new antirheumatic drug. Now we describe herein the preparation of the enantiomers of (+/-)-deacetylesonarimod, the pharmaceutically active metabolites of esonarimod, and comparison of their antirheumatic activities. No significant difference has been observed between the two enantiomers. In a pre-clinical study of esonarimod, ...
Laurens J B - - 2002
A validated gas chromatography-mass spectrometric method for the analysis of the metabolites of benzene and its alkylated analogues in urine is reported. A number of metabolites, as required by authorities for biomonitoring of industrial exposure to aromatic vapour, were analysed simultaneously with preservation of quantitative information concerning positional isomers. The ...
Wiwanitkit Viroj - - 2002
Urine hippuric acid determination is helpful for monitoring of group of workers at risk for exposure to toluene. However, some problems about the external source of variation are mentioned. Some studies have indicated that smoking is an important external source of variation for determination of urine hippuric acid level while ...
Caux Chantal - - 2002
In accomplishing their duties, firefighters are potentially exposed to a vast array of toxic combustion and pyrolysis products such as benzene, carbon monoxide, acrolein, nitrogen dioxide, and polycyclic aromatic hydrocarbons. Exposure to PAH and benzene was assessed by means of urinary measurements of 1-hydroxypyrene and t,t-muconic acid, respectively. All urine ...
Song Heng - - 2002
In vitro studies have demonstrated that water-soluble, nontoxic phosphoramidates of azidothymidine (zidovudine [AZT]) have significant and specific anti-human immunodeficiency virus and anticancer activity. Although polar, these compounds are internalized and processed to the corresponding nucleoside monophosphates. Eight methyl amide and methyl ester phosphoramidate monoesters composed of D- or L-phenylalanine or ...
Yan Maohe - - 2002
Dobutamine is a synthetic ionotropic catecholamine commonly used to treat heart failure and shock. The catabolic fate of dobutamine in humans has yet to be reported, although formation of 3-O-methyldobutamine represents the principal pathway of dobutamine disposition in the dog. Herein, we describe the isolation and identification of 3-O-methyldobutamine in ...
Teichert Jens - - 2002
An isocratic reversed-phase HPLC method for the simultaneous quantitation of alpha-lipoic acid and five of its metabolites in human plasma as well as in human urine employing solid-phase extraction and pulsed amperometric detection was developed and validated. The method was found to be sufficiently precise and accurate for the measurement ...
Nakazawa Takahiro - - 2002
The metabolic fate of [6]-gingerol, one of the active constituents of Zingiber officinale Roscoe, was investigated using rats. The bile of rats orally administered [6]-gingerol was shown to contain a major metabolite (1) by HPLC analysis. Although the metabolites derived from [6]-gingerol were not detected in the urine, the ethyl ...
Inoue Osamu - - 2002
OBJECTIVE: To examine if benzylmercapturic acid (or N-acetyl- S-benzyl cysteine) in urine can be used as a marker of occupational exposure to toluene. METHODS: A factory survey was conducted in the latter half of a working week. A group of 46 men, who volunteered for the study, was engaged in ...
Toora B D - - 2002
Creatinine in serum or urine is determined by Jaffe's reaction where creatinine produces quantitatively an orange color with picric acid in alkaline medium. After allowing an incubation time of 15 min at room temperature for color development the color is measured at 520 nm. Without taking into consideration the acidic ...
Saudubray J M - - 2002
There are almost one hundred inborn errors of metabolism which can start in the neonatal period, but less than 20 are amenable to treatment. In general, an extremely evocative clinical setting is the course of a full-term baby born after normal pregnancy and delivery who, after an initial symptom-free period ...
Meyer Michael A - - 2002
A 22-year-old woman with a negative urine drug screen and somnolence rapidly reversed by intravenous flumazenil was found to have elevated ammonia levels and punctate calcifications of the subcortical frontal white matter. Abnormally high levels of orotic acid were found in serum and urine, confirming the diagnosis of ornithine transcarbamylase ...
Manini Paola - - 2002
Liquid chromatography with electrospray tandem mass spectrometry was used to characterize the metabolism of styrene in man and in rat. To improve identification and characterization of minor styrene metabolites, rats were co-exposed to styrene and styrene-d(8). In addition to the main styrene metabolites, mandelic acid and phenylglyoxylic acid, and specific ...
Swiercz Radosław - - 2002
The objective of this study was to evaluate the toxicokinetics and metabolism of pseudocumene after inhalation exposure. Male Wistar rats were exposed to pseudocumene vapors at nominal concentrations of 25,100 or 250 ppm in the dynamic inhalation chambers for 6 h. Blood samples were collected during (between 1st and 6th ...
Mangione A M - - 2001
We studied the relationship between the use of three detoxification pathways and urine pH and the tolerance of desert woodrats from two populations to a mixture of naturally occurring plant secondary metabolites (mostly phenolics) in resin from creosote bush (Larrea tridentata). The two populations of desert woodrats came from the ...
Carlsson S - - 2001
Nitrite may be generated by bacteria in urine during urinary tract infections. Acidification of nitrite results in the formation of nitric oxide (NO) and other reactive nitrogen oxides, which are toxic to a variety of microorganisms. We have studied NO formation and bacterial growth in mildly acidified human urine containing ...
Masutomi N - - 2001
Allyl isothiocyanate (AITC) is known to be weakly carcinogenic, whereas benzyl isothiocyanate (BITC) has been suggested to exert carcinogenicity toward the rat urinary bladder. To elucidate direct toxic effects of isothiocyanates (ITCs), BITC, AITC, or BITC-metabolites conjugated either with glutathione, cysteinylglycine, cysteine, or mercapturic acid were intravesically instilled into female ...
Milardović S - - 2001
This paper describes the performance of a biosensor with an Ru(III), Ni(II), and Fe(II) hexacyanometallate-modified graphite electrode and immobilized oxalate oxidase for the determination of urinary oxalate. The addition of ruthenium enhances the electrochemical reversibility and chemical stability of the electrocrystallized layer and improves the sensitivity of the biosensor. Hydrogen ...
Sato K - - 2001
Olfactory lamellae of teleosts contain two morphologically different types of olfactory receptor neurons (ORNs): ciliated ORNs (cORNs) and microvillous ORNs (mORNs). However, little is known about the functional difference between these two types of ORNs in fish olfaction. We isolated cORNs and mORNs using a Ca(2+)-free solution method from olfactory ...
Hardt J - - 2001
Pyrethroid insecticides are widely used in agriculture and private households. Analysis of urine for pyrethroid metabolites is one way to detect human exposure to these insecticides and is carried out regularly as part of the Occupational and Environmental Medicine Monitoring Program recommended by the Deutsche Forschungsgemeinschaft (DFG). Samples are analyzed ...
Breyer-Pfaff U - - 2001
In experiments with expressed human UDP-glucuronosyltransferase 1A4 (UGT1A4), the antipsychotic clozapine proved to be conjugated to two different glucuronides, one of which was identified as the quaternary ammonium glucuronide derivatized at the N-methylpiperazine group; this compound had previously been isolated from patient urine. An additional glucuronide produced in larger quantity ...
De Palma G - - 2001
The role of polymorphic xenobiotic-metabolizing enzymes in the interindividual variability of phenylhydroxyethyl mercapturic acids (PHEMAs) was investigated in 56 styrene-exposed workers. Ambient monitoring was carried out using passive personal samplers (geometric mean, 157 mg/m3 8-h time-weighted average; geometric standard deviation, 2.90). Biomonitoring was based on mandelic acid and phenylglyoxylic acid ...
Krawczyk H - - 2001
Proton decoupled high resolution 13C NMR spectra of argininosuccinic acid have been measured in a series of dilute water solutions of various acidity. These data have provided a basis for unequivocal determination of the presence of this metabolite in the investigated sample. The method additionally enables simultaneous rough estimation of ...
Qu Y - - 2001
BACKGROUND: The Beckman 6300/7300 analyzer, which was widely used for amino acid (AA) analysis, is no longer commercially available. METHODS: To set up an affordable AA analysis program, a Beckman system gold HPLC 126AA analyzer and Pickering Laboratories reagents were used. Two quantitative AA analysis programs were developed. One was ...
Engel W - - 2001
The major in vivo metabolites of S-(+)- and R-(-)-carvone in a metabolism of ingestion correlated amounts (MICA) experiment were newly identified as alpha,4-dimethyl-5-oxo-3-cyclohexene-1-acetic acid (dihydrocarvonic acid), alpha-methylene-4-methyl-5-oxo-3-cyclohexene-1-acetic acid (carvonic acid), and 5-(1,2-dihydroxy-1-methylethyl)-2-methyl-2-cyclohexen-1-one (uroterpenolone) on the basis of mass spectral analysis in combination with syntheses and NMR experiments. Minor metabolites were ...
Verhagen H - - 2001
Allium vegetables (onions, leeks, chives) and in particular garlic have been claimed to have health-promoting potential. This study was conducted to get insight into the perspectives for monitoring the intake of garlic by a biomarker approach. Chemically, the biomarker results from exposure to gamma-glutamyl-S-allyl-l-cysteine, which is first hydrolysed by gamma-glutamine-transpeptidase ...
Boyle R - - 2001
The in vivo metabolic fate of 1,8-cineole was investigated in six male koalas. Koalas were fed ad lib a diet of Eucalyptus cephalocarpa leaf with a 1,8-cineole concentration of 2.53+/-0.70% dry mass of leaf, corresponding to a 1,8-cineole intake of 2.4+/-1.1 mmol/kg (3.1+/-1.3 g). Urine and faeces were collected for ...
Wahl H G - - 2001
A gas chromatographic-mass spectrometric method was developed for the quantitative analysis of the three Di(2-ethylhexyl)phthalate (DEHP) metabolites, 2-ethylhexanoic acid, 2-ethyl-3-hydroxyhexanoic acid and 2-ethyl-3-oxohexanoic acid in urine. After oximation with O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine hydrochloride and sample clean-up with Chromosorb P filled glass tubes, all three organic acids were converted to their tert.-butyldimethylsilyl derivatives. ...
de Freitas Filho L G - - 2001
PURPOSE: To verify in an experimental model whether gastrocystoplasty may protect patients with chronic renal failure from acid loading associated acidosis a wedge-shaped portion of the middle stomach was used to improve bladder capacity in animals with chronic renal failure. MATERIALS AND METHODS: An experimental model was used to study ...
Rankin G O - - 2001
The agricultural fungicide N-(3,5-dichlorophenyl)succinimide (NDPS) induces nephrotoxicity in vivo that is characterized as acute polyuric renal failure and proximal tubular necrosis. However, earlier in vitro studies have failed to reproduce the in vivo nephrotoxicity seen with NDPS or its nephrotoxic metabolites N-(3,5-dichlorophenyl)-2-hydroxysuccinimide (NDHS) and N-(3,5-dichlorophenyl)-2-hydroxysuccinamic acid (2-NDHSA). The purpose of ...
Cooper J - - 2001
Residues of 19-nortestosterone (19-NT) and diethylstilboestrol (DES) are excreted in bovine urine, mainly conjugated to glucuronic acid. Prior to quantification, urine must be deconjugated, which is commonly performed by enzymatic or chemical hydrolysis. The efficiencies of two enzymatic and two chemical deconjugation methods were studied. The range of efficiencies obtained ...
Bhasin A - - 2001
The efficacy of some putative attractants for the biting midge Culicoides impunctatus (Goetghebuer) (Diptera: Ceratopogonidae) was assessed using odour-baited 'delta traps' and suction traps. 1-octen-3-ol was confirmed as a potent olfactory attractant for C. impunctatus when released at 0.06mg/h. Acetone (23mg/h) and a mix of six phenolic compounds (phenol, 3-ethylphenol, ...
Lim H K - - 2001
The enantiomeric separation of metoprolol and its metabolites in human urine was undertaken using capillary electrophoresis (CE). Resolution of the enantiomers was achieved using carboxymethyl-beta-cyclodextrin (CM-beta-CD) as the chiral selector. A 100-mM acetate buffer (pH 4.0) containing 5% 2-propanol and 10 mM CM-beta-CD resulted in the optimum separation of the ...
Chamarro J - - 2001
[5-3H, 1'-14C, 13C6, 12C] Indole-3-acetic acid (IAA), was applied to the flavedo (epicarp) of intact orange fruits at different stages of development. After incubation in the dark, at 25 degrees C, the tissue was extracted with MeOH and the partially purified extracts were analyzed by reversed phase HPLC-RC. Six major ...
Maurer H H - - 2001
Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used as analgesic and anti-rheumatic drugs, and they are often misused. A gas chromatographic-mass spectrometric (GC-MS) screening procedure was developed for their detection in urine as part of a systematic toxicological analysis procedure for acidic drugs and poisons after extractive methylation. The compounds were ...
Yamada M - - 2001
The sodium salt of 6-hydroxy-5-(phenylazo)-2-naphthalenesulfonic acid (SS-AN), which is a subsidiary color present in Food Yellow No. 5 [Sunset Yellow FCF, disodium salt of 6-hydroxy-5-(4-sulfophenylazo)-2-naphthalenesulfonic acid], was orally administered to Sprague-Dawley rats. Metabolite A, metabolite B, and unaltered SS-AN were detected as colored metabolites in the rat urine. Analysis of ...
Walker V - - 2001
4-Heptanone is a common volatile constituent of human urine and is of unknown origin. We hypothesised that it arises from in vivo beta-oxidation of 2-ethylhexanoic acid (EHA) from plasticisers, similar to formation of 3-heptanone from valproic acid. We investigated urine from individuals with normal and increased plasticiser exposure. Using GC/MS, ...
Venta R - - 2001
BACKGROUND: Reversed-phase HPLC (RP-HPLC) has become an alternative to ion-exchange chromatography for amino acid analysis in biological fluids. However, validation studies for its urine application are limited, and the corresponding reference values have not been reported extensively. We studied the long-term performance of a commercial HPLC method for urine amino ...
Akinyinka O O - - 2001
Consumption of caffeine containing products is very popular in African children, particularly during ill health in the belief that caffeine promotes good health. This study aims to define the metabolism of caffeine, which takes place in the liver in a group of healthy Nigerian children. About 100 mg of caffeine ...
Bloemen L J - - 2001
OBJECTIVES: To investigate in humans the contribution of the cytochrome P-450- and glutathione-dependent biotransformation of trichloroethylene (TRI) under controlled repeated exposure in volunteers, and under occupational conditions. METHODS: Volunteers were exposed to TRI, using repeated 15 min exposures at 50 and 100 ppm. This exposure schedule resulted in internal doses ...
Yoshimura T - - 2001
A microplate enzyme immunoassay (EIA) was developed for the measurement of glycine- and taurine-conjugated 7alpha-hydroxy-3-oxo-4-cholenoic acids (CDCA-delta4-3-one) in human urine. The antiserum was prepared by immunizing rabbits with N-(7alpha-hydroxy-3-oxo-4-cholen-24-oyl)-3-aminopropionic acid--bovine serum albumin conjugate. A colorimetric EIA was established using horseradish peroxidase-labeled antigen having a shorter bridge length than that of ...
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