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Hippuric Acid (hippuric + acid)
Selected AbstractsCrystal growth of some urinary stone constituents: II.CRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2002In-vitro crystallization of hippuric acid Abstract Hippuric acid [C6H5CONHCH2COOH], one of the organic chemical constituents of urinary stone is crystallized in silica gel under suitable pH conditions by double diffusion method. The grown crystals were characterized by density measurement, Fourier transform infrared spectroscopy, X-ray powder diffraction and thermogravimetric analysis. [source] Benzofuranyl-pyran-2-ones, -pyridazines, and -pyridones from naturally occurring furochromones (visnagin and khellin)HETEROATOM CHEMISTRY, Issue 1 2004Eman M. Keshk The novel and versatile enaminones 2a,b were synthesized by treatment of visnaginone methyl ether 1a or khellinone methyl ether 1b with N,N -dimethylformamide dimethylacetal. They were reacted with hippuric acid or N -acetylglycine to yield benzofuran-5-yl-2H-pyran-2-ones 3a,d. The reaction of 2a,b with cyanoacetamide and malononitrile dimer in sodium ethoxide gave benzofuran-5-yl-pyridones 4a,b and [benzofuran-5-yl-1H-pyridine-2-ylidene] malononitrile 5a, respectively. Refluxing 2a,b with hydrazine hydrate or with hydroxyla- mine afforded benzofuran-5-yl-1H-pyrazoles 6a,b and benzofuran-5-yl-isoxazoles 7a,b, respectively. Moreover, 2a,b coupled with aryl diazonium salt in the presence of sodium hydroxide to yield 3-(benzofuran-5-yl)-2-aryl-hydrazono-3-oxo-propanals 8a,b which were excellent precursors for the synthesis of pyridazines 9,12. © 2003 Wiley Periodicals, Inc. 15:85,91, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10219 [source] White blood cell sister chromatid exchange among a sample of Thai subjects exposed to toluene, an observationINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 6 2006Viroj Wiwanitkit Summary There is a particular concern with toluene because some research has indicated that toluene exposure could result in chronic toxicity including mutagenesis and carcinogenesis. This study aimed to determine the rate of sister chromatid exchanges (SCE), a marker for genotoxicity, and its correlation to the classical urine biomarker for toluene exposure, urine hippuric acid, among a sample of Thai exposed subjects. A total of 26 police (all males) were included in this study. The average (mean ± SD) urine hippuric acid level in these police was 0.8 ± 0.4 mg/g creatinine. The average (mean ± SD) SCE level in these police was 4.5 ± 1.0/cell. The average SCE among the police with high urine hippuric acid levels was non-significantly higher than the average SCE level of those without (P = 0.41). This implies that the cytogenetic response to toluene was not different between the subjects with and without high toluene exposure. High exposure to toluene seems not to be related to high SCE. [source] Effects of an ethanol,gasoline mixture: results of a 4-week inhalation study in ratsJOURNAL OF APPLIED TOXICOLOGY, Issue 3 2005I. Chu Abstract The inhalation toxicity of an ethanol,gasoline mixture was investigated in rats. Groups of 15 male and 15 female rats were exposed by inhalation to 6130 ppm ethanol, 500 ppm gasoline or a mixture of 85% ethanol and 15% gasoline (by volume, 6130 ppm ethanol and 500 ppm gasoline), 6 h a day, 5 days per week for 4 weeks. Control rats of both genders received HEPA[sol ]charcoal-filtered room air. Ten males and ten females from each group were killed after 4 weeks of treatment and the remaining rats were exposed to filtered room air for an additional 4 weeks to determine the reversibility of toxic injuries. Female rats treated with the mixture showed growth suppression, which was reversed after 4 weeks of recovery. Increased kidney weight and elevated liver microsomal ethoxyresorufin- O -deethylase (EROD) activity, urinary ascorbic acid, hippuric acid and blood lymphocytes were observed and most of the effects were associated with gasoline exposure. Combined exposure to ethanol and gasoline appeared to exert an additive effect on growth suppression. Inflammation of the upper respiratory tract was observed only in the ethanol,gasoline mixture groups, and exposure to either ethanol and gasoline had no effect on the organ, suggesting that an irritating effect was produced when the two liquids were mixed. Morphology in the adrenal gland was characterized by vacuolation of the cortical area. Although histological changes were generally mild in male and female rats and were reversed after 4 weeks, the changes tended to be more severe in male rats. Brain biogenic amine levels were altered in ethanol- and gasoline-treated groups; their levels varied with respect to gender and brain region. Although no general interactions were observed in the brain neurotransmitters, gasoline appeared to suppress dopamine concentrations in the nucleus accumbens region co-exposed to ethanol. It was concluded that treatment with ethanol and gasoline, at the levels studied, produced mild, reversible biochemical hematological and histological effects, with some indications of interactions when they were co-administered. Copyright © 2005 John Wiley & Sons, Ltd. [source] Studies with enaminones: synthesis of new coumarin-3-yl azoles, coumarin-3-yl azines, coumarin-3-yl azoloazines, coumarin-3-yl pyrone and coumarin-2-yl benzo[b]FuransJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2001Fathy Mohamed Abel Aziz El-Taweel 3-Acetylcoumarine was condensed with dimethylformamide dimethylacetal (DMFDMA) to yield the enaminone, which reacts readily with hydroxylamine and with hydrazines to yield coumarin-3-ylisoxazoles and coumarin-3-ylpyrazoles respectively. Reaction of the enaminone with benzamidine hydrochloride and 3-amino-1,2,4-1H -triazole affords the pyrimidine and triazolo[3,4- b]pyrimidine. The enaminone reacts with hippuric acid and with the dithiocarboxylic acid to yield pyranones. The reaction of the enaminone with 3-amino-1H -1,2,4-triazole gives the triazolo[3,4- b]pyrimidine. The enaminone underwent self dimerization on reflux in acetic acid ammonium acetate to yield the coumarinyl pyridines and reacted with ketone under the same conditions to yield the pyridine. The reaction of the enaminone with 1,4-benzoquinone and 1,4-naphthoquinone gives benzofuryl coumarine derivatives. [source] Inhibition of serum angiotensin-converting enzyme in rabbits after intravenous administration of enalaprilat-loaded intact erythrocytesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 9 2001Mehrdad Hamidi Encapsulation of drugs in intact erythrocytes, because of the profound characteristics of these natural microspheres, has gained considerable attention in recent years. In this study, the inhibition time courses of serum angiotensin-converting enzyme (ACE) activity after intravenous administration of enalaprilat encapsulated in intact erythrocytes was evaluated and compared with free drug, in a rabbit model. Three groups of animals each received free drug, drug-loaded erythrocytes or sham-encapsulated erythrocytes. Serum ACE activity was determined in each case using the synthetic substrate hippuryl-histidyl-leucine and quantitation of the hippuric acid released by a developed and validated HPLC method. The serum ACE inhibition profiles in the three groups showed that the encapsulated drug inhibited the serum ACE more slowly, more efficiently, over a considerably longer time and in a more reproducible manner, than the free drug or sham-encapsulated erythrocytes. We conclude that the erythrocytes can serve as efficacious slow-release drug carriers for enalaprilat in circulation. [source] Analysis of urinary biomarkers for exposure to alkyl benzenes by isotope dilution gas chromatography-mass spectrometryJOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2005Adriaan A. S. Marais Abstract A validated GC-MS method for the analysis of urinary metabolites of alkyl benzenes is reported. Metabolites for exposure to toluene, xylene and ethylbenzene were analyzed simultaneously using stable isotope substituted internal standards. The method entailed acidic deconjugation of urine samples followed by extractive alkylation with pentafluorobenzyl bromide as alkylating agent. The resulting pentafluorobenzyl derivatives of ortho -, meta -, para -cresol, mandelic acid (MA), hippuric acid (HA) and ortho -, meta -, para -methylhippuric acid (MHA) were then quantified by SIM. Optimized reaction conditions for the extractive alkylation step are reported. The derivatives were found to be sufficiently stable for overnight batch analysis. The LODs were below 0.1 ,mol/L for the cresols and below 1 ,mol/L for MA and the HAs. Within-batch precision for o -MHA was 7%, for m -MHA 5%, for p -MHA 5.2% and below 5% for the rest of the analytes. [source] Prospective Evaluation of the Change of Predialysis Protein-Bound Uremic Solute Concentration With Postdilution Online HemodiafiltrationARTIFICIAL ORGANS, Issue 7 2010Natalie Meert Abstract Although protein-bound uremic compounds have been related to outcome in observational studies, few current dialysis strategies provide more removal of those compounds than standard hemodialysis. We evaluated the evolution of protein-bound uremic solutes after a switch from high-flux hemodialysis to postdilution hemodiafiltration (n = 13). We compared predialysis solute concentration at 4, 5, and 9 weeks versus baseline for several protein-bound compounds and water-soluble solutes, as well as for ,2 -microglobulin. After 9 weeks of postdilution hemodiafiltration, a significant decrease versus baseline could be detected for total concentration of protein-bound solutes: p-cresylsulfate (3.98 ± 1.51,3.17 ± 1.77 mg/dL, ,20%, P < 0.01) and 3-carboxyl-4-methyl-5-propyl-2-furanpropionic acid (0.72 ± 0.52,0.64 ± 0.46 mg/dL, ,11%, P < 0.01). For the other protein-bound solutes, hippuric acid, indoleacetic acid, and indoxylsulfate, no change in total concentration could be detected. The concentration of the middle molecule, ,2 -microglobulin, decreased as well after 9 weeks of postdilution hemodiafiltration (24.7 ± 9.3,18.1 ± 6.7 mg/L, ,27%, P < 0.01). For water-soluble compounds, no significant change of concentration was found. Postdilution hemodiafiltration in comparison to high-flux hemodialysis provided significant reduction of predialysis concentration of protein-bound compounds, especially those with the highest protein binding, and of ,2 -microglobulin, by ,11 to ,27% in 9 weeks. [source] A rapid assay for angiotensin-converting enzyme activity using ultra-performance liquid chromatography,mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 3 2010Fang Geng Abstract Angiotensin-converting enzyme (ACE) plays an important role in the renin,angiotensin system and ACE activity is usually assayed in vitro by monitoring the transformation from a substrate to the product catalyzed by ACE. A rapid and sensitive analysis method or ACE activity by quantifying simultaneously the substrate hippuryl,histidyl,leucine and its product hippuric acid using an ultra-performance liquid chromatography coupled with electrospray ionization-mass spectrometry (UPLC-MS) was first developed and applied to assay the inhibitory activities against ACE of several natural phenolic compounds. The established UPLC-MS method showed obvious advantages over the conventional HPLC analysis in shortened running time (3.5,min), lower limit of detection (5,pg) and limit of quantification (18,pg), and high selectivity aided by MS detection in selected ion monitoring (SIM) mode. Among the six natural products screened, five compounds, caffeic acid, caffeoyl acetate, ferulic acid, chlorogenic acid and resveratrol indicated potent in vitro ACE inhibitory activity with IC50 values of 2.527 ± 0.032, 3.129 ± 0.016, 10.898 ± 0.430, 15.076 ± 1.211 and 6.359 ± 0.086,mm, respectively. A structure,activity relationship estimation suggested that the number and the situation of the hydroxyls on the benzene rings and the acrylic acid groups may play the most predominant role in their ACE inhibitory activity. Copyright © 2009 John Wiley & Sons, Ltd. [source] Determination of organic acids in urine by solid-phase microextraction and gas chromatography,ion trap tandem mass spectrometry previous ,in sample' derivatization with trimethyloxonium tetrafluoroborateBIOMEDICAL CHROMATOGRAPHY, Issue 10 2008Marco Pacenti Abstract A method for the determination of the organic acids directly in the urine employing derivatization with trimethyloxonium tetrafluoroborate as a methylating agent and sequential extraction by head space and direct immersion/solid phase microextraction is reported. Furoic acid, hippuric acid, methylhippuric acid, mandelic acid, phenylglyoxylic acid and trans, trans muconic acid contained in urine and proposed by the American Conference of Governmental Industrial Hygienists as biological exposure indices were determined after a fast and economically convenient preparation step and sensitive gas chromatography,ion trap,mass spectrometry/tandem mass spectrometry analysis. Urine is rather a complex sample and hence the acquisition method required specific GC-MS instrumentation capable of supporting the changeover, fully automated during a single chromatographic separation, from mass to tandem mass spectrometry and both chemical and electron ionization modes. The automation of the analytical method provides a number of advantages, including reduced analysis time for both routine analysis and method development, and greater reproducibility. The equilibrium and kinetics of this substances vs head space/direct immersion-solid phase microextraction were investigated and evaluated theoretically. Copyright © 2008 John Wiley & Sons, Ltd. [source] Capillary Zone Electrophoresis of some organic acids in milk wheyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 5 2003Francesca Buiarelli Abstract This paper describes a method for analysing some acids of milk whey by Capillary Zone Electrophoresis. After eliminating the whey proteins by ultrafiltration, the whey underwent electrophoretic separation in the presence of anodic electroosmotic flow. The following analytes were detected: citric, orotic, uric, and hippuric acids. A procedure is described for sample preparation and the operating conditions for electrophoretic capillary separation established. Finally, orotic acid is quantitatively determined. [source] | |||||||||||||