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Results 351 - 400 of 1392
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Frederiksen H - - 2004
2-amino-9H-pyrido[2,3-b]indole (AalphaC) is a mutagenic and carcinogenic heterocyclic amine formed during ordinary cooking. In model systems AalphaC can be formed by pyrolysing either tryptophan or proteins of animal or vegetable origin. In the present study, the in vivo metabolism of AalphaC in rats was investigated. Rats were dosed with tritium ...
Thiesen Flavia Valladão - - 2004
In order to measure urinary level of hippuric acid among Brazilian homeless youth suspected of having inhaled toluene in previous hours, urine samples were voluntarily collected from the youth around two hours after they arrived at an "open-school" in Porto Alegre, Brazil. Hippuric acid levels were determined by gas chromatography ...
Ben-Brik E - - 2004
OBJECTIVES: Glycol ethers are solvents that are present in a large number of products used commercially and domestically. During recent years, ethylene glycol ether derivatives, in particular ethylene glycol methyl ether and ethylene glycol ethyl ether, have been progressively replaced by propylene glycol ether derivatives, which are less toxic. The ...
Hmiel Stanley Paul - - 2004
OBJECTIVE: Assessment of amino acid clearances by continuous venovenous hemodialysis with filtration in treatment of a metabolic decompensation in acute maple syrup urine disease. DESIGN: Single patient assessment. SETTING: Pediatric intensive care unit. PATIENTS: A 10-yr-old male with known maple syrup urine disease (branched chain alpha-ketoacid dehydrogenase deficiency) with metabolic ...
Waidyanatha Suramya - - 2004
A gas chromatography-mass spectrometry method for measurement of the main urinary metabolites of benzene, namely, phenol, catechol, hydroquinone, 1,2,4-trihydroxybenzene (trihydroxybenzene), t,t-muconic acid (muconic acid), and S-phenylmercapturic acid (phenylmercapturic acid), is reported. The method is considerably simpler than existing assays. It was applied to urine from benzene-exposed subjects and controls from ...
Glew Robert H - - 2004
BACKGROUND: Preeclampsia/eclampsia is one of the major causes of maternal and fetal mortality in Nigeria and many other countries in sub-Saharan Africa. We determined if serum and urine concentrations of amino acids were abnormal in women with this disorder of pregnancy in Gombe, Nigeria. METHODS: Free amino acids were measured ...
Rorsman Hans - - 2004
As a redhead I have had a personal interest in red hair, freckles and sunburns since childhood. An observation of a formaldehyde-induced fluorescence in human epidermal melanocytes initiated my scientific interest in these cells. Prota and Nicolaus demonstrated that oxidation products of cysteinyldopas are the main components of pheomelanin. Our ...
Illsinger Sabine - - 2004
3-Methylglutaconic-aciduria type I (MGA1, OMIM 250950) resulting from 3-Methylglutaconyl-coenzyme A hydratase deficiency is a rare inherited metabolic disorder of l-leucine catabolism. We diagnosed this condition in a 4-year-old German male with generalized fever-associated seizures from the age of 12 months and normal psychomotor development. First he was considered to suffer ...
Inoue O - - 2004
The present study was initiated to examine whether urinary benzylmercapturic acid (or N-acetyl-S-benzyl cysteine, BMA), a mercapturate metabolite of toluene, increases in relation to the intensity of toluene exposure, and whether this metabolite is a better marker of occupational exposure to toluene than two traditional markers, hippuric acid and o-cresol. ...
Baba Seigo - - 2005
BACKGROUND: Rosmarinic acid (RA) is a natural polyphenolic substance contained in many Lamiaceae herbs such as Perilla frutescens. Previous studies have shown RA has antioxidative and anti-inflammatory activity. However, little is known on the absorption, metabolism, degradation and excretion of RA. AIM OF THE STUDY: The aim of this study ...
Guiberteau Agustina - - 2004
Nalidixic acid (NA) and its main metabolite, 7-hydroxymethylnalidixic acid (OH-NA), are simultaneously determined by applying artificial neural networks (ANNs), to their square wave voltammetric signals. The scores of a PCR model, built with the voltammetric data of a set of standard samples, recorded between -0.70 and -1.0V, are used as ...
Miller Randall R - - 2004
Glucuronides of piperazine hydroxylamines are rarely reported in the literature, and even more rarely are their structures unambiguously identified. One major metabolite was detected by liquid chromatography/mass spectrometry-radioactivity in urine from monkeys treated with the aryl piperazine oral hypoglycemic agent 9-[(1S,2R)-2-fluoro-1-methylpropyl]-2-methoxy-6-(1-piperazinyl) purine hydrochloride (1). The mass spectrum of this metabolite ...
Strauss Arnold W - - 2004
Genetic disorders of amino acid and fatty acid metabolism can be detected with tandem mass spectrometry (MS/MS). MS/MS screening of mice subjected to chemical mutagenesis (see the related article beginning on page 434) defined a new disorder of branched-chain amino acid metabolism resembling human maple syrup urine disease. This approach ...
Todoroki Yasushi Y Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, Shizuoka 422-8529, Japan. - - 2004
We synthesized 5'alpha,8'-cycloabscisic acid (CycloABA), a highly potent and long-lasting abscisic acid (ABA) analogue, by a different method from that reported before. CycloABA fed to radish seedlings had more metabolic tolerance than ABA. The major metabolite of CycloABA was the glucose conjugate, which was the minor metabolite of ABA. The ...
Salwa
Twenty-eight urine samples were collected from healthy, male and female, young and adult camels (Camelus dromedarus), cattle, goat and human.Samples were physically, chemically, microscopically, and biochemically examined for determination of pH, specific gravity, chloride, phosphate, sulphate, bicarbonate, uric acid, urea, creatinine, creatine, total protein, albumin, macro elements (Ca++, Mg+, Na+, ...
Kautzleben Michael - - 2004
The anticoagulant r-hirudin lepirudin is eliminated exclusively via the kidneys. We examined the C-terminal amino acid degradation of lepirudin by the proximal kidney tubulus cells in humans as well as the antithrombotic efficacy of the metabolites and quantified the metabolite portions. In vitro metabolites of lepirudin were produced by adding ...
Proudfoot A T - - 2004
This Position Paper was prepared using the methodology agreed by the American Academy of Clinical Toxicology (AACT) and the European Association of Poisons Centres and Clinical Toxicologists (EAPCCT). All relevant scientific literature was identified and reviewed critically by acknowledged experts using set criteria. Well-conducted clinical and experimental studies were given ...
Sondossi M - - 2004
The purpose of this investigation was to examine the capacity of the biphenyl catabolic enzymes of Comamonas testosteroni B-356 to metabolize dihydroxybiphenyls symmetrically substituted on both rings. Data show that 3,3'-dihydroxybiphenyl is by far the preferred substrate for strain B-356. However, the dihydrodiol metabolite is very unstable and readily tautomerizes ...
Ponce G - - 2004
The TaqIA1 allele of the dopamine receptor gene D2 (DRD2) has been associated with alcoholism, as well as with other addictive behaviours. The exact nature of how the presence of this allele can be a vulnerability factor in the development of alcoholism remains unclear. In this study we found that ...
Parvex P - - 2003
Children with fully recessive (Type I/I) cystinuria have a high risk of stone formation in the first decade of life. To assess the tendency for cystine to precipitate in individual urine samples, we developed an in vitro assay in which radiolabelled cystine (4mM) was dissolved in urine at 37 degrees ...
Carlsson S - - 2003
Dietary and endogenous nitrates are excreted in urine, and during infection with nitrate-reducing bacteria they are reduced to nitrite. At a low pH nitrite is converted to a variety of nitrogen oxides that are toxic to bacteria. We hypothesized that acidification of nitrite-rich infected urine would result in the killing ...
Muñoz Jose A - - 2003
An ICPMS method for the determination of phytic acid in human urine based on the total phosphorus measurement of purified extracts of phytic acid is described. Pretreatment of the sample is required to avoid interference in the ICPMS detection from other phosphorus compounds accompanying phytic acid in urine such as ...
Chace Donald H - - 2003
BACKGROUND: Over the past decade laboratories that test for metabolic disorders have introduced tandem mass spectrometry (MS/MS), which is more sensitive, specific, reliable, and comprehensive than traditional assays, into their newborn-screening programs. MS/MS is rapidly replacing these one-analysis, one-metabolite, one-disease classic screening techniques with a one-analysis, many-metabolites, many-diseases approach that ...
Nakazawa Takahiro - - 2003
As a part of our search for the active metabolite from the bark of Magnolia officinalis (Magnoliaceae), the aqueous extract was orally administered to rats, and metabolites in the urine were analysed by a high-performance liquid chromatograph equipped with a photodiode array detector. When the extract was given to rats, ...
Hoffer L John - - 2003
BACKGROUND: N-acetyl-L-tyrosine (NAT) is commonly used in place of tyrosine in parenteral nutrition, but human studies carried out to date indicate considerable amounts of it are excreted unchanged in the urine. NAT retention has not been well studied in parenterally fed adults. METHODS: NAT retention was measured in 13 adults ...
Sperlingová I - - 2004
The reference material was prepared by freeze-drying pooled urine samples obtained from healthy persons occupationally exposed to styrene. The concentrations of mandelic acid (MA), phenylglyoxylic acid (PGA), and hippuric acid (HA) in urine were determined by three modes of high-performance liquid chromatography (HPLC). For isochronous stability testing the urinary mandelic ...
Chen L-J - - 2003
(R)-(+)-Menthofuran is a metabolite of (R)-(+)-pulegone, the chief constituent of pennyroyal oil. Menthofuran has been shown to account for a significant percentage of pulegone toxicity through further metabolism to a reactive intermediate, an enonal (2-Z-(2'-keto-4'-methylcyclohexylidene)propanal). Hydration of the enonal followed by a 1,4-dehydration and rearrangement gives rise to diastereomeric (-)-mintlactone ...
Jones K - - 2003
2-Butoxyethanol is a glycol ether widely used in printing inks, varnishes and cleaning fluids. As skin absorption can be significant, biological monitoring is useful in monitoring worker exposure. A number of analytes and matrices have been used previously, including 2-butoxyethanol in blood and free and total 2-butoxyacetic acid in urine. ...
Mani Ali R - - 2003
Reactive nitrogen species, such as peroxynitrite, can nitrate tyrosine in proteins to form nitrotyrosine. Nitrotyrosine is metabolized to 3-nitro-4-hydroxyphenylacetic acid (NHPA), which is excreted in the urine. This has led to the notion that measurement of urinary NHPA may provide a time-integrated index of nitrotyrosine formation in vivo. However, it ...
Yoshida Kaoru - - 2003
Our long-term oral administration of dimethylarsinic acid (DMAV) in rats revealed that three unidentified metabolites, M-1, M-2, and M-3, were detected in urine and feces. DMAV and trimethylarsine oxide (TMAO) were converted to M-2 and M-3 and M-1 by Escherichia coli strain A3-6 isolated from the ceca of DMAV-administered rats, ...
Kohri Toshiyuki - - 2003
After intravenous administration of (-)-epicatechin gallate to Wistar male rats, its biliary metabolites were examined. Deconjugated forms of (-)-epicatechin gallate metabolites were prepared by beta-glucuronidase/sulfatase treatment and purified by HPLC. Five compounds were subjected to FAB-MS and NMR analyses. These metabolites were shown to be (-)-epicatechin gallate, 3'-O-methyl-(-)-epicatechin gallate, 4'-O-methyl-(-)-epicatechin ...
Sprague Christopher L - - 2003
Epidemiological studies have indicated that 1,3-butadiene exposure is associated with an increased risk of leukemia. In human liver microsomes, 1,3-butadiene is rapidly oxidized to butadiene monoxide, which can then be hydrolyzed to 3-butene-1,2-diol (BDD). In this study, BDD and several potential metabolites were characterized in the urine of male B6C3F1 ...
Senda C - - 2003
1. The study was performed to isolate and characterize a glucuronic acid conjugate of mexiletine that releases mexiletine on acid hydrolysis from urine samples obtained from healthy volunteers following a single oral dose of mexiletine. 2. The [M-H]- ion of the isolated metabolite was observed at m/z 398 in the ...
Hofmann Ute - - 2003
Enzyme deficiencies in pyrimidine metabolism are associated with a risk for severe toxicity against the antineoplastic agent 5-fluorouracil. To assess whether urinary levels of pyrimidines and their metabolites can be used for predicting patients' individual phenotype, a new gas chromatographic-tandem mass spectrometric method was developed which allows the simultaneous determination ...
Wang I-Jen - - 2003
Maple syrup urine disease (MSUD) is a rare inborn error of the branched chain amino acid metabolism, which can be classified as classical, intermediate, intermittent, and thiamine responsive types. We report a 16-day-old boy who suffered from difficult feeding, persistent metabolic acidosis, and tricycling movement of the lower legs. Status ...
Fleming David E - - 2003
The existence of intracrystalline proteins and amino acids in calcium oxalate monohydrate was demonstrated by X-ray synchrotron diffraction studies. Their presence has implications for the destruction of calcium oxalate crystals formed in the urinary tract and the prevention of kidney stones. INTRODUCTION: Although proteins are present in human kidney stones, ...
Hardt Jochen - - 2003
OBJECTIVES: Pyrethroids are applied as insecticides throughout the world. Human metabolism of pyrethroids results in urinary metabolites that are suitable for biological monitoring. The aim of the study was to evaluate individual exposure due to occupational application of pyrethroids as a precondition for the assessment of health risks. METHODS: Thirty-six ...
Vermeulen Martijn - - 2003
Cruciferous vegetables contain glucosinolates, which are degraded to isothiocyanates. These are easily absorbed, conjugated to glutathione, and excreted into the urine as their corresponding mercapturic acids. We have developed and validated a solid phase extraction-high-performance liquid chromatography-electrospray ionization mass spectrometry/mass spectrometry method for the specific analysis of individual isothiocyanate mercapturic ...
Li Ke - - 2003
9-Nitro-20(S)-camptothecin is a novel anticancer drug. In this study, metabolites of 9-nitro-20(S)-camptothecin in rats were identified. Rats were dosed with the drug, and the metabolites in the bile were isolated and collected by high-performance liquid chromatography using a gradient elution. By LC/MSn(n =1-3), the biliary metabolites in addition to the ...
Gonthier Marie-Paule - - 2003
Chlorogenic acid, the ester of caffeic acid with quinic acid, is one of the most abundant polyphenols in the human diet with coffee, fruits and vegetables as its major sources. Its antioxidant and anticarcinogenic properties have been well established in animal studies. However, little is known about its gut absorption ...
Renwick Andrew G - - 2003
The risk assessment of compounds added to foods or taken as supplements is usually based on hazard characterization studies performed in animal test species. A large default uncertainty factor, or margin or exposure, is usually required to allow for possible species differences and human variability in the toxicokinetics and toxicodynamics ...
McLean Stuart - - 2003
Glucuronuria is normal in marsupial folivores such as the koala (Phascolarrctos cinereus), which excretes 2-3 g glucuronic acid daily. Although this has long been attributed to the metabolites of Eucalyptus terpenes, we have found that these are mostly excreted in the unconjugated form. We now report on the aglycones that ...
Lee Stephen T - - 2003
The consumption of ponderosa pine (Pinus ponderosa), lodgepole pine (Pinus contorta), common juniper (Juniperus communis), and Monterey cypress (Cupressus macrocarpa) causes abortions in pregnant cattle. Recent studies have identified isocupressic acid (1) as the primary abortificient compound in these plants. In vitro and in vivo studies using rumen and blood ...
Balkman Cheryl E - - 2003
OBJECTIVE: To evaluate 3 methods for measuring urine bile acids (UBA) and compare their diagnostic performance with that of the serum bile acids (SBA) test and other routine screening tests in dogs with hepatic disorders. DESIGN: Prospective study. ANIMALS: 15 healthy dogs, 102 dogs with hepatic disorders, and 9 dogs ...
Bilecen Deniz - - 2003
This study describes for the first time results of a (19)F-MRS study on humans exposed to the fluorinated non-steroidal anti-inflammatory drug niflumic acid. The accumulation and elimination of this commercially available selective prostaglandin synthase inhibitor is studied after an oral bolus in the human liver, in blood plasma and in ...
Walker Valerie - - 2003
BACKGROUND: From investigations of a child with hyperprolinaemia type II, we demonstrated in vitro that pyridoxal phosphate forms a novel adduct with a proline metabolite, pyrroline-5-carboxylic acid, through Claisen condensation. Studies indicated that this was a previously unsuspected generic reaction of aldehydes and some ketones. We have subsequently found the ...
Blackledge C A - - 2003
Following the administration of 2-, 3- and 4-fluorobenzyl alcohols, the major metabolites detected in urine corresponded to the glycine conjugates of the corresponding benzoic acids. Little, or no, unchanged parent compound was detected in the samples. In addition to glycine-conjugated benzoic acids, a small proportion of the urinary metabolites for ...
Trainor D - - 2003
Urine bile acid (UBA) tests reflecting "average" serum bile acid (SBA) concentrations may have greater practical utility than paired SBA samples in cats. This study evaluated whether urine sulfated bile acids (USBAs), urine nousulfated bile acids (UNSBAs), or a combined approach had a clinical utility equivalent to SBAs. Routine serum ...
Mareska Michael C - - 2003
Glutaric acidemia type II (GA II) typically presents with profound metabolic acidosis, hypoketotic hypoglycemia, and mild dysmorphic features in newborns. Since its description, 11 patients with adult-onset GA II have been reported. A 23-year-old woman presented at 6 months gestation with preterm labor and weakness for 3 months. Her weakness ...
Leng Gabriele - - 2003
A prospective epidemiological study with respect to pyrethroid exposure was carried out combining clinical examination, indoor monitoring and biological monitoring. The results of the biological monitoring are presented. Biological monitoring was performed in 57 persons before (T1) as well as 1 day (T2), 3 days (T3), 4-6 months (T4), and ...
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