@article {506, title = {Metabolism of pyrene by two clam species, Mya arenaria and Protothaca staminea}, journal = {Chemosphere}, volume = {49}, number = {3}, year = {2002}, note = {ISI Document Delivery No.: 595QETimes Cited: 11Cited Reference Count: 29}, month = {Oct}, pages = {315-322}, type = {Article}, abstract = {Two species of marine clam, Mya arenaria and Protothaca staminea, were exposed to pyrene and 1-hydroxypyrene in small glass aquaria. After 10 days of exposure the clams were sacrificed, and both clam tissue and seawater were assayed for pyrene metabolites by using HPLC, fluorescence spectroscopy, HPLC-ESI-MS, GC-MS and H-1-NMR spectrometry. 1-Pyrenol-1-hydrogensulfate (pyrene-1-sulfate) was identified as the major water soluble metabolite formed from both pyrene and 1-hydroxypyrene by both species of clam. 1-Hydroxypyrene was identified as a minor metabolite of pyrene, and pyrenediol-hydrogen sulfate was identified as a minor metabolite of 1-hydroxypyrene. (C) 2002 Elsevier Science Ltd. All rights reserved.}, keywords = {BENZOPYRENE, BIOMARKERS, biotransformation, contaminant, EXPOSURE, mollusk, PAHs, polycyclic aromatic hydrocarbons, POLYCYCLIC AROMATIC-HYDROCARBONS, SEDIMENTS, SOUND}, isbn = {0045-6535}, url = {://000178119600012}, author = {Simpson, C. D. and Cullen, W. R. and He, T. Y. T. and Ikonomou, M. and Reimer, K. J.} } @article {4862, title = {Determination of monomethylarsonous acid, a key arsenic methylation intermediate, in human urine}, journal = {Environmental Health Perspectives}, volume = {108}, number = {11}, year = {2000}, note = {ISI Document Delivery No.: 373XPTimes Cited: 101Cited Reference Count: 48}, month = {Nov}, pages = {1015-1018}, type = {Article}, abstract = {In this study we report on the finding of monomethylarsonous acid [MMA(III)I in human urine. This newly identified arsenic species is a key intermediate in the metabolic pathway of arsenic biomethylation, which involves stepwise reduction of pentavalent to trivalent arsenic species followed by oxidative addition of a methyl group. Arsenic speciation was carried out using ion-pair chromatographic separation of arsenic compounds with hydride generation atomic fluorescence spectrometry detection. Speciation of the inorganic arsenite [As(III)], inorganic arsenate [As(V)], monomethylarsonic acid [MMA(V)], dimethylarsinic acid [DMA(V)], and MMA(III) in a urine sample was complete in 5 min. Urine samples collected from humans before and after a single oral administration of 300 mg sodium 2,3-dimercapto-1-propane sulfonate (DMPS) were analyzed for arsenic species. MMA(III) was found in 51 out of 123 urine samples collected from 41 people in inner Mongolia 0-6 hr after the administration of DMPS. MMA(III)in urine samples did not arise from the reduction of MMA(V) by DMPS. DMPS probably assisted the release of MMA(III) that was formed in the body. Along with the presence of MMA(III), there was an increase in the relative concentration of MMA(V) and a decrease in DMA(V) in the urine samples collected after the DMPS ingestion.}, keywords = {3-dimercapto-1-propane sulfonate, ARSENIC SPECIATION, BIOMARKERS, CARCINOGENESIS, CHEMICAL FORMS, DIMETHYLARSINIC ACID, ENZYMATIC METHYLATION, EXCRETION, EXPOSURE, GLUTATHIONE-REDUCTASE, INGESTION, METABOLISM, METABOLITES, METHYLATION, MONOMETHYLARSONOUS ACID, sodium 2, SPECIATION, trivalent methylarsenic species, urine metabolites}, isbn = {0091-6765}, url = {://000165315600019}, author = {Le, X. C. and Ma, M. S. and Lu, X. F. and Cullen, W. R. and Aposhian, H. V. and Zheng, B. S.} } @article {4861, title = {Speciation of key arsenic metabolic intermediates in human urine}, journal = {Analytical Chemistry}, volume = {72}, number = {21}, year = {2000}, note = {ISI Document Delivery No.: 369XXTimes Cited: 187Cited Reference Count: 45}, month = {Nov}, pages = {5172-5177}, type = {Article}, abstract = {Biomethylation is the major human metabolic pathway for inorganic arsenic, and the speciation of arsenic metabolites is essential to a better understanding of arsenic metabolism and health effects. Here we describe a technique for the speciation of arsenic in human urine and demonstrate its application to the discovery of key arsenic metabolic intermediates, monomethylarsonous acid (MMA(III)) and dimethylarsinous acid (DMA(III)), in human urine. The study provides a direct evidence in support of the proposed arsenic methylation pathway in the human. The finding of MMA(III) and DMA(III) in human urine, along with recent studies showing the high toxicity of these arsenicals, suggests that the usual belief of arsenic detoxification by methylation needs to be reconsidered, The arsenic speciation technique is based on ion pair chromatographic separation of arsenic species on a 3-mum particle size column at 50 degreesC followed by hydride generation atomic fluorescence detection. Speciation of MMA(III), DMA(III), arsenite (As-III), arsenate (As-V), monomethylarsonic acid(MMA(V)), and dimethylarsinic acid (DMA(V)) in urine samples is complete in 6 min with detection limits of 0.5-2 mug/L. There is no need for any sample pretreatment. The capability of rapid analysis of trace levels of arsenic species, which resulted in the findings of the key metabolic intermediates, makes the technique useful for routine arsenic speciation analysis required for toxicological and epidemiological studies.}, keywords = {ATOMIC FLUORESCENCE DETECTION, BLACKFOOT DISEASE, DRINKING-WATER, EXCRETION, EXPOSURE, INGESTION, METHYLATION, PERFORMANCE LIQUID-CHROMATOGRAPHY, SEPARATION, TEMPERATURE}, isbn = {0003-2700}, url = {://000165094000012}, author = {Le, X. C. and Lu, X. F. and Ma, M. S. and Cullen, W. R. and Aposhian, H. V. and Zheng, B. S.} } @article {4535, title = {Sample preparation and storage can change arsenic speciation in human urine}, journal = {Clinical Chemistry}, volume = {45}, number = {11}, year = {1999}, note = {ISI Document Delivery No.: 251HUTimes Cited: 70Cited Reference Count: 543rd International Conference on Arsenic Exposure and Health EffectsJUL 12-15, 1998SAN DIEGO, CALIFORNIA}, month = {Nov}, pages = {1988-1997}, type = {Proceedings Paper}, abstract = {Background: Stability of chemical speciation during sample handling and storage is a prerequisite to obtaining reliable results of trace element speciation analysis. There is no comprehensive information on the stability of common arsenic species, such as inorganic arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid, dimethylarsinic acid, and arsenobetaine, in human urine. Methods: We compared the effects of the following storage conditions on the stability of these arsenic species: temperature (25, 4, and -20 degrees C), storage time (1, 2, 4, and 8 months), and the use of additives (HCl, sodium azide, benzoic acid, benzyltrimethyl ammonium chloride, and cetylpyridinium chloride). HPLC with both inductively coupled plasma mass spectrometry and hydride generation atomic fluorescence detection techniques were used for the speciation of arsenic. Results: We found that all five of the arsenic species were stable for up to 2 months when urine samples were stored at 4 and -20 degrees C without any additives. For longer period of storage (4 and 8 months), the stability of arsenic species was dependent on urine matrices. Whereas the arsenic speciation in some urine samples was stable for the entire 8 months at both 4 and -20 degrees C, other urine samples stored under identical conditions showed substantial changes in the concentration of As(III), As(V), monomethylarsonic acid, and dimethylarsinic acid. The use of additives did not improve the stability of arsenic speciation in urine. The addition of 0.1 mol/L HCl (final concentration) to urine samples produced relative changes in inorganic As(III) and As(V) concentrations. Conclusions: Low temperature (4 and -20 degrees C) conditions are suitable for the storage of urine samples for up to 2 months. Untreated samples maintain their concentration of arsenic species, and additives have no particular benefit. Strong acidification is not appropriate for speciation analysis. (C) 1999 American Association for Clinical Chemistry.}, keywords = {CARCINOGENESIS, CHEMICAL FORMS, DIMETHYLARSINIC ACID, DRINKING-WATER, EXCRETION, EXPOSURE, MASS-SPECTROMETRIC DETECTION, METABOLITES, METHYLATION PATTERNS, PERFORMANCE LIQUID-CHROMATOGRAPHY}, isbn = {0009-9147}, url = {://000083440300015}, author = {Feldmann, J. and Lai, V. W. M. and Cullen, W. R. and Ma, M. S. and Lu, X. F. and Le, X. C.} }