@article {797,
	title = {Do arsenosugars pose a risk to human health? The comparative toxicities of a trivalent and pentavalent arsenosugar},
	journal = {Environmental Science \& Technology},
	volume = {38},
	number = {15},
	year = {2004},
	note = {ISI Document Delivery No.: 842WOTimes Cited: 23Cited Reference Count: 54},
	month = {Aug},
	pages = {4140-4148},
	type = {Article},
	abstract = {Seafood frequently contains high concentrations of arsenic (similar to10-100 mg/kg dry weight). In marine algae (seaweed), this arsenic occurs predominantly as ribose derivatives known collectively as arsenosugars. Although it is clear that arsenosugars are not acutely toxic, there is a possibility of arsenosugars having slight chronic toxicity. In general, trivalent arsenicals are more toxic than their pentavalent counterparts, so in this work we examine the hypothesis that trivalent arsenosugars might be significantly more toxic than pentavalent arsenosugars in vitro. We compared the in vitro toxicity of (R)-2,3-dihydroxypropyl-5-deoxy-5-dimethylarsinoyl-beta-D-riboside, a pentavalent arsenosugar, to that of its trivalent counterpart, (R)-2,3-dihydroxypropyl-5-deoxy-5-dimethylarsino-beta-D- riboside. The trivalent arsenosugar nicked plasmid DNA, whereas the pentavalent arsenosugar did not. The trivalent arsenosugar was more cytotoxic (IC50 = 200 muM, 48 h exposure) than its pentavalent counterpart (IC50 > 6000 muM, 48 h exposure) in normal human epidermal keratinocytes in vitro as determined via the neutral red uptake assay. However, both the trivalent and the pentavalent arsenosugars were significantly less toxic than MMA(III), DMA(III), and arsenate. Neither the pentavalent arsenosugar nor the trivalent arsenosugar were mutagenic in Salmonella TA104. The trivalent arsenosugar was readily formed by reaction of the pentavalent arsenosugar with thiol compounds, including, cysteine, glutathione, and dithioerythritol. This work suggests that the reduction of pentavalent arsenosugars to trivalent arsenosugars in biology might have environmental consequences, especially because seaweed consumption is a significant environmental source for human exposure to arsenicals.},
	keywords = {DIMETHYLARSINIC ACID, DNA-DAMAGE, HUMAN-CELLS, IN-VITRO, INORGANIC ARSENICS, METABOLISM, METHYLATED ARSENICALS, MONOMETHYLARSONOUS ACID MMA(III), ORGANIC ARSENIC COMPOUNDS, SEAWEED},
	isbn = {0013-936X},
	url = {<Go to ISI>://000223035400022},
	author = {Andrewes, P. and Demarini, D. M. and Funasaka, K. and Wallace, K. and Lai, V. W. M. and Sun, H. S. and Cullen, W. R. and Kitchin, K. T.}
}
@article {465,
	title = {DNA damage induced by methylated trivalent arsenicals is mediated by reactive oxygen species},
	journal = {Chemical Research in Toxicology},
	volume = {15},
	number = {12},
	year = {2002},
	note = {ISI Document Delivery No.: 627VUTimes Cited: 104Cited Reference Count: 48},
	month = {Dec},
	pages = {1627-1634},
	type = {Article},
	abstract = {Arsenic is a human carcinogen; however, the mechanisms of arsenic{\textquoteright}s induction of carcinogenic effects have not been identified clearly. We have shown previously that monomethylarsonous acid (MMA(III)) and dimethylarsinous acid (DMA(III)) are genotoxic and can damage supercoiled phiX174 DNA and the DNA in peripheral human lymphocytes in culture. These trivalent arsenicals are biomethylated forms of inorganic arsenic and have been detected in the urine of subjects exposed to arsenite and arsenate. We show here by molecular, chemical, and physical methods that reactive oxygen species (ROS) are intermediates in the DNA-damaging activities of MMA(III) and DMA(III). Using the phiX174 DNA nicking assay we found that the ROS inhibitors Tiron, melatonin, and the vitamin E analogue Trolox inhibited the DNA-nicking activities of both MMA(III) and DMA(III) at low micromolar concentrations. The spin trap agent 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) also was effective at preventing the DNA nicking induced by MMA(III) and DMA(III.) ESR spectroscopy studies using DMPO identified a radical as a ROS intermediate in the DNA incubations with DMA(III). This radical adduct was assigned to the DMPO-hydroxyl free radical adduct on the basis of comparison of the observed hyperfine splitting constants and line widths with those reported in the literature. The formation of the DMPO-hydroxyl free radical adduct was dependent on time and the presence of DMA(III) and was completely inhibited by Tiron and Trolox and partially inhibited by DMSO. Using electrospray mass spectrometry, micromolar concentrations of DMA(v) were detected in the DNA incubation mixtures with DMA(III). These data are consistent with the conclusions that the DNA-damaging activity of DMA(III) is an indirect genotoxic effect mediated by ROS-formed concomitantly with the oxidation of DMA(III) to DMA(v).},
	keywords = {DIMETHYLARSINIC ACID, DRINKING-WATER, ENZYMATIC METHYLATION, FREE-RADICALS, HEPATOCYTES, HUMAN, HUMAN URINE, MALE F344 RATS, MONOMETHYLARSONOUS ACID MMA(III), ORAL-EXPOSURE, RAT-LIVER CYTOSOL},
	isbn = {0893-228X},
	url = {<Go to ISI>://000179957500017},
	author = {Nesnow, S. and Roop, B. C. and Lambert, G. and Kadiiska, M. and Mason, R. P. and Cullen, W. R. and Mass, M. J.}
}
@article {330,
	title = {Plasmid DNA damage caused by methylated arsenicals, ascorbic acid and human liver ferritin},
	journal = {Toxicology Letters},
	volume = {133},
	number = {1},
	year = {2002},
	note = {ISI Document Delivery No.: 575QMTimes Cited: 46Cited Reference Count: 499th International Congress of ToxicologyJUL 08-12, 2001BRISBANE, AUSTRALIA},
	month = {Jul},
	pages = {47-57},
	type = {Proceedings Paper},
	abstract = {Both dimethylarsinic acid (DMA(V)) and dimethylarsinous acid (DMA(III)) release iron from human liver ferritin (HLF) with or without the presence of ascorbic acid. With ascorbic acid the rate of iron release from HLF by DMA(V) was intermediate (3.37 nM/min, P < 0.05) and by DMA(III) was much higher (16.3 nM/min, P < 0.001). No pBR322 plasmid DNA damage was observed from in vitro exposure to arsenate (iAs(V)), arsenite (iAs(III)), monomethylarsonic acid (MMA(V)), monomethylarsonous acid (MMA(III)) or DMA(V) alone. DNA damage was observed following DMA(III) exposure; coexposure to DMA(III) and HLF caused more DNA damage; considerably higher amounts of DNA damage was caused by coexposure of DMA(III), HLF and ascorbic acid. Diethylenetriaminepentaacetic acid (an iron chelator), significantly inhibited DNA damage. Addition of catalase (which can increase Fe2+ concentrations) further increased the plasmid DNA damage. Iron-dependent DNA damage could be a mechanism of action of human arsenic carcinogenesis. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.},
	keywords = {arsenic, BIOCHEMICAL PARAMETERS, CARCINOGENESIS, DIMETHYLARSINIC ACID, dimethylarsinous acid, DMA(111), DNA damage, ENDOTHELIAL-CELLS, human liver ferritin, INDUCTION, INORGANIC ARSENICS, iron, MICE, MONOMETHYLARSONOUS ACID, reactive oxygen, species, STRAND BREAKS},
	isbn = {0378-4274},
	url = {<Go to ISI>://000176959200005},
	author = {Ahmad, S. and Kitchin, K. T. and Cullen, W. R.}
}
@article {5045,
	title = {Determination of trivalent methylated arsenicals in biological matrices},
	journal = {Toxicology and Applied Pharmacology},
	volume = {174},
	number = {3},
	year = {2001},
	note = {ISI Document Delivery No.: 464KTTimes Cited: 129Cited Reference Count: 67},
	month = {Aug},
	pages = {282-293},
	type = {Article},
	abstract = {The enzymatically catalyzed oxidative methylation of As yields methylated arsenicals that contain pentavalent As (As-V). Because trivalent As (As-III) is the favored substrate for this methyltransferase, methylated arsenicals containing As-V are reduced to trivalency in cells. Methylated arsenicals that contain As-III are extremely potent inhibitors of NADPH-dependent flavoprotein oxidoreductases and potent cytotoxins in many cell types. Therefore, the formation of methylated arsenicals that contain As-III may be properly regarded as an activation step, rather than a means of detoxification. Recognition of the role of methylated arsenicals that contain As-III in the toxicity and metabolism of As emphasizes the need for analytical methods to detect and quantify these species in biological samples. Hence, a method was developed to exploit pH-dependent differences in the generation of arsines from inorganic and methylated arsenicals that contain either As-V or As-III. Reduction with borohydride at pH 6 generated arsines from inorganic As-III, methyl As-III, and dimethyl As-III, but not from inorganic As-V, methyl As-V, and dimethyl As-V. Reduction with borohydride at pH 2 or lower generated arsines from arsenicals that contained either As-V or As-III. Arsines are trapped in a liquid nitrogen-cooled gas chromatographic trap, which is subsequently warmed to allow separation of the hydrides by their boiling points. Atomic absorption spectrophotometry is used to detect and quantify the arsines. The detection limits (ng As ml(-1)) for inorganic As-III, methyl As-III, and dimethyl As-III are 1.1, 1.2, and 6.5, respectively. This method has been applied to the analysis of arsenicals in water, human urine, and cultured cells. Both methyl As-III. and dimethyl As-III are detected in urine samples from individuals who chronically consumed inorganic As-contaminated water and in human cells exposed in vitro to inorganic As-III. The reliable quantitation of inorganic and methylated arsenicals that contain As-III. in biological samples will aid the study of the toxicity of these species and may provide a new biomarker of the effects of chronic exposure to As. (C) 2001 Academic Press.},
	keywords = {analysis, arsenic, atomic absorption spectrophotometry, biological matrices, CANCER MORTALITY, DIABETES-MELLITUS, DIMETHYLARSINIC ACID, DOSE-RESPONSE RELATIONSHIP, DRINKING-WATER, ENZYMATIC, HUMAN URINE, HYDRIDE GENERATION, MAMMALIAN SYSTEMS, MASS-SPECTROMETRY, METABOLISM, methylated arsenic, METHYLATION, MONOMETHYLARSONOUS ACID MMA(III), pentavalent arsenic, STABILITY, TOXICITY, trivalent arsenic},
	isbn = {0041-008X},
	url = {<Go to ISI>://000170532300010},
	author = {Del Razo, L. M. and Styblo, M. and Cullen, W. R. and Thomas, D. J.}
}
@article {5144,
	title = {Methylated trivalent arsenic species are genotoxic},
	journal = {Chemical Research in Toxicology},
	volume = {14},
	number = {4},
	year = {2001},
	note = {ISI Document Delivery No.: 424XZTimes Cited: 253Cited Reference Count: 55},
	month = {Apr},
	pages = {355-361},
	type = {Article},
	abstract = {The reactivities of methyloxoarsine (MAsIII) and iododimethylarsine (DMAsIII), two methylated trivalent arsenicals, toward supercoiled phi X174 RFI DNA were assessed using a DNA nicking assay. The induction of DNA damage by these compounds in vitro in human peripheral lymphocytes was assessed using a single-cell gel (SCG, "comet") assay. Both methylated trivalent arsenicals were able to nick and/or completely degrade phi X174 DNA in vitro in 2 h incubations at 37 degreesC (pH 7.4) depending on concentration. MAsIII was effective at nicking phi X174 DNA at 30 mM; however, at 150 muM DMAsIII, nicking could be observed. Exposure of (phi X174 DNA to sodium arsenite (iAs(III); from 1 nM up to 300 mM), sodium arsenate (from 1 muM to 1 M), and the pentavalent arsenicals, monomethylarsonic acid (from 1 muM to 3 M) and dimethylarsinic acid (from 0.1 to 300 mM), did not nick or degrade phi X174 DNA under these conditions. In the SCG assay in human lymphocytes, methylated trivalent arsenicals were much more potent than any other arsenicals that were tested. On the basis of the slopes of the concentration-response curve for the tail moment in the SCG assay, MAsIII and DMAsIII were 77 and 386 times more potent than iAs(III), respectively. Because methylated trivalent arsenicals were the only arsenic compounds that were observed to damage naked DNA and required no exogenously added enzymatic or chemical activation systems, they are considered here to be direct-acting forms of arsenic that are genotoxic, though they are not, necessarily, the only genotoxic species of arsenic that could exist.},
	keywords = {CELLS, DIMETHYLARSINIC ACID, DRINKING-WATER, ENZYMATIC METHYLATION, FIBROBLASTS, GLUTATHIONE-REDUCTASE, HUMAN, HUMAN URINE, INHIBITION, MONOMETHYLARSONOUS ACID, SODIUM ARSENITE},
	isbn = {0893-228X},
	url = {<Go to ISI>://000168260400005},
	author = {Mass, M. J. and Tennant, A. and Roop, B. C. and Cullen, W. R. and Styblo, M. and Thomas, D. J. and Kligerman, A. D.}
}
@article {4717,
	title = {Arsenic species that cause release of iron from ferritin and generation of activated oxygen},
	journal = {Archives of Biochemistry and Biophysics},
	volume = {382},
	number = {2},
	year = {2000},
	note = {ISI Document Delivery No.: 367PNTimes Cited: 90Cited Reference Count: 61},
	month = {Oct},
	pages = {195-202},
	type = {Article},
	abstract = {The in vitro effects of four different species of arsenic (arsenate, arsenite, monomethylarsonic acid, and dimethylarsinic acid) in mobilizing iron from horse spleen ferritin under aerobic and anaerobic conditions were investigated. Dimethylarsinic acid (DMA((V))) and dimethylarsinous acid (DMA((III))) significantly released iron from horse spleen ferritin either with or without the presence of ascorbic acid, a strong synergistic agent. Ascorbic acid-mediated iron release was time-dependent as well as both (DMA((III))) and ferritin concentration-dependent. Iron release from ferritin by DMA((III)) alone or with ascorbic acid was not significantly inhibited by superoxide dismutase (150 or 300 units/ml). However, the iron release was greater under anaerobic conditions (nitrogen gas), which indicates direct chemical reduction of iron from ferritin by DMA((III)), with or without ascorbic acid. Both DMA((V)) and DMA((III)) released iron from both horse spleen and human liver ferritin. Further, the release of ferritin-iron by DMA((III)) with ascorbic acid catalyzed bleomycin-dependent degradation of calf thymus DNA. These results indicate that exogenous methylated arsenic species and endogenous ascorbic acid can cause (a) the release of iron from ferritin, (b) the iron-dependent formation of reactive oxygen species, and (c) DNA damage. This reactive oxygen species pathway could be a mechanism of action of arsenic carcinogenesis in man. (C) 2000 Academic Press.},
	keywords = {arsenic, ascorbic acid, BIOCHEMICAL PARAMETERS, DAMAGE, DIMETHYLARSINIC ACID, DNA-DAMAGE, ferritin, FREE-RADICALS, INORGANIC ARSENICS, iron, LIPID-PEROXIDATION, MAIN METABOLITE, OXIDATIVE, oxygen species, REACTIVE, reactive oxygen, VITAMIN-C},
	isbn = {0003-9861},
	url = {<Go to ISI>://000090070800005},
	author = {Ahmad, S. and Kitchin, K. T. and Cullen, W. R.}
}
@article {4942,
	title = {Comparative toxicity of trivalent and pentavalent inorganic and methylated arsenicals in rat and human cells},
	journal = {Archives of Toxicology},
	volume = {74},
	number = {6},
	year = {2000},
	note = {ISI Document Delivery No.: 349ZATimes Cited: 358Cited Reference Count: 37},
	month = {Aug},
	pages = {289-299},
	type = {Article},
	abstract = {Biomethylation is considered a major detoxification pathway for inorganic arsenicals (iAs). According to the postulated metabolic scheme, the methylation of iAs yields methylated metabolites in which arsenic is present in both pentavalent and trivalent forms. Pentavalent mono- and dimethylated arsenicals are less acutely toxic than iAs. However, little is known about the toxicity of trivalent methylated species. In the work reported here the toxicities of iAs and trivalent and pentavalent methylated arsenicals were examined in cultured human cells derived from tissues that are considered a major site for iAs methylation (liver) or targets for carcinogenic effects associated with exposure to iAs (skin, urinary bladder, and lung). To characterize the role of methylation in the protection against toxicity of arsenicals, the capacities of cells to produce methylated metabolites were also examined. In addition to human cells, primary rat hepatocytes were used as methylating controls. Among the arsenicals examined, trivalent monomethylated species were the most cytotoxic in all cell types. Trivalent dimethylated arsenicals were at least as cytotoxic as trivalent iAs (arsenite) for most cell types. Pentavalent arsenicals were significantly less cytotoxic than their trivalent analogs. Among the cell types examined, primary rat hepatocytes exhibited the greatest methylation capacity for iAs followed by primary human hepatocytes, epidermal keratinocytes, and bronchial epithelial cells. Cells derived from human bladder did not methylate iAs. There was no apparent correlation between susceptibility of cells to arsenic toxicity and their capacity to methylate iAs. These results suggest that (1) trivalent methylated arsenicals, intermediary products of arsenic methylation, may significantly contribute to the adverse effects associated with exposure to iAs, and (2) high methylation capacity does not protect cells from the acute toxicity of trivalent arsenicals.},
	keywords = {ARSENATE, arsenic, ARSENITE, BINDING, bladder, cell culture, CELLULAR UPTAKE, DIMETHYLARSINIC ACID, dimethylarsinous acid, DRINKING-WATER, ENZYMATIC METHYLATION, GLUTATHIONE, HEPATOCYTES, HUMAN, IN-VITRO METHYLATION, LIVER, lung, METABOLISM, methylarsonic acid, methylarsonous acid, METHYLATION, RABBIT LIVER, SKIN, TOXICITY},
	isbn = {0340-5761},
	url = {<Go to ISI>://000089074500001},
	author = {Styblo, M. and Del Razo, L. M. and Vega, L. and Germolec, D. R. and LeCluyse, E. L. and Hamilton, G. A. and Reed, W. and Wang, C. and Cullen, W. R. and Thomas, D. 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 = {<Go to ISI>://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 {4901,
	title = {Monomethylarsonous acid (MMA(III)) is more toxic than arsenite in Chang human hepatocytes},
	journal = {Toxicology and Applied Pharmacology},
	volume = {163},
	number = {2},
	year = {2000},
	note = {ISI Document Delivery No.: 295TBTimes Cited: 294Cited Reference Count: 28},
	month = {Mar},
	pages = {203-207},
	type = {Article},
	abstract = {Methylation has been considered to be the primary detoxication pathway of inorganic arsenic. Inorganic arsenic is methylated by many, but not all animal species, to monomethylarsonic acid (MMA(V)), monomethylarsonous acid (MMA(III)), and dimethylarsinic acid (DMA(V)). The As-V derivatives have been assumed to produce low toxicity, but the relative toxicity of MMA(III) remains unknown. In vitro toxicities of arsenate, arsenite, MMA(V), MMA(III) and DMA(V) were determined in Chang human hepatocytes, Leakage of lactate dehydrogenase (LDH) and intracellular potassium (K+) and mitochondrial metabolism of the tetrazolium salt XTT were used to assess cytotoxicity due to arsenic exposure. The mean LC50 based on LDH assays in phosphate media was 6 mu M for MMA(III) and 68 mu M for arsenite. Using the assay for K+ leakage in phosphate media, the mean LC50 was 6.3 mu M for MMA(III) and 19.8 mu M for arsenite. The mean LC50 based on the XTT assay in phosphate media was 13.6 mu M for MMA(III) and 164 mu M for arsenite. The results of the three cytotoxicity assays (LDH, K+, and XTT) reveal the following order of toxicity in Chang human hepatocytes: MMA(III) > arsenite > arsenate > MMA(V) = DMA(V). Data demonstrate that MMA(III) an intermediate in inorganic arsenic methylation, is highly toxic and again raises the question as to whether methylation of inorganic arsenic is a detoxication process. (C) 2000 Academic Press.},
	keywords = {ARSENATE, ARSENITE, ASSAY, CELLS, Chang human hepatocytes, DIMETHYLARSINIC ACID, DMA, DMA(V), DMPS, ENZYMATIC METHYLATION, LDH, LIVER, MICE, MMA(III), MMA(V), monomethylarsonic acid, MONOMETHYLARSONOUS ACID, POTASSIUM, VIABILITY, XTT},
	isbn = {0041-008X},
	url = {<Go to ISI>://000085983000013},
	author = {Petrick, J. S. and Ayala-Fierro, F. and Cullen, W. R. and Carter, D. E. and Aposhian, H. V.}
}
@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 = {<Go to ISI>://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.}
}
@article {4552,
	title = {The separation of dimethylarsinic acid, methylarsonous acid, methylarsonic acid, arsenate and dimethylarsinous acid on the Hamilton PRP-X100 anion-exchange column},
	journal = {Applied Organometallic Chemistry},
	volume = {13},
	number = {11},
	year = {1999},
	note = {ISI Document Delivery No.: 255DLTimes Cited: 24Cited Reference Count: 29},
	month = {Nov},
	pages = {837-843},
	type = {Article},
	abstract = {In order to separate the potential arsenite metabolites methylarsonous acid and dimethylarsinous acid from arsenite, arsenate, methylarsonic acid and dimethylarsinic acid, the pH-dependent retention behaviour of all six arsenic compounds was studied on a Hamilton PRP-X100 anion-exchange column with 30 mM phosphate buffers (pH 5, 6, 7, 8 and 9) containing 20\% (v/v) methanol as mobile phase and employing an inductively coupled plasma atomic emission spectrometer (ICP-AES) as the arsenic-specific detector. Baseline separation of dimethylarsinic acid, methylarsonous acid, methylarsonic acid, arsenate and dimethylarsinous acid was achieved with a 30 mmol dm(-3) phosphate buffer (pH 5)-methanol mixture (80:20, v/v) in 25 min. Arsenite is not baseline-separated from dimethylarsinic acid under these conditions, Copyright (C) 1999 John Wiley \& Sons, Ltd.},
	keywords = {ARSENATE, ARSENITE, BEHAVIOR, DIMETHYLARSINIC ACID, dimethylarsinous acid, ENVIRONMENT, ENZYMATIC METHYLATION, GLUTATHIONE, HPLC-ICP-AES, LAKE-BIWA, METABOLISM, METHYLARSENICALS, methylarsonic acid, methylarsonous acid, SPECIATION, SPECTROMETRY},
	isbn = {0268-2605},
	url = {<Go to ISI>://000083654200005},
	author = {Gailer, J. and Madden, S. and Cullen, W. R. and Denton, M. B.}
}
@article {4345,
	title = {Vesicular membrane permeability of monomethylarsonic and dimethylarsinic acids},
	journal = {Biophysical Chemistry},
	volume = {70},
	number = {1},
	year = {1998},
	note = {ISI Document Delivery No.: YU539Times Cited: 6Cited Reference Count: 45},
	month = {Jan},
	pages = {75-85},
	type = {Article},
	abstract = {The transmembrane permeability coefficients of the environmentally sensitive arsenicals, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) have been measured for egg phosphatidylcholine large unilamellar vesicles. The determination of the vesicle concentration-independent first-order rate constants for membrane transport and the permeability coefficients were made using an NMR technique employing shift agents. The permeability coefficient of DMA was found to be two orders of magnitude greater than that of MMA. This is attributed to the presence of MMAs extra hydroxyl group. Both species are shown to permeate membranes in the neutral form. Both the temperature dependence and the dependence on cholesterol content were investigated for DMA. The activation energy and the Arrhenius preexponential factor were found to be dependent on the cholesterol content. A marked increase in both parameters was observed up to 20 mol.\% cholesterol, with a further, small increase up to 60\%, The significance of these results to our understanding of membrane transport is discussed. The importance of using permeability coefficients rather than n-octanol/water partition coefficients in determining bioavailability and bioaccumulation of environmentally sensitive compounds is also discussed. (C) 1998 Elsevier Science B.V.},
	keywords = {BILE-ACIDS, CHOLESTEROL, DIFFUSION, DIMETHYLARSINIC ACID, HUMAN-ERYTHROCYTES, LIPID BILAYER-MEMBRANES, monomethylarsonic acid, NONELECTROLYTE, nuclear magnetic resonance, PARTITION-COEFFICIENTS, permeability, phosphatidylcholine membranes, RAPID EXTRUSION PROCEDURE, TRANSPORT, UNILAMELLAR VESICLES},
	isbn = {0301-4622},
	url = {<Go to ISI>://000071728000008},
	author = {Males, R. G. and Nelson, J. C. and Phillips, P. S. and Cullen, W. R. and Herring, F. G.}
}
@article {3938,
	title = {The effect of organotin compounds on the permeability of model biological membranes},
	journal = {Applied Organometallic Chemistry},
	volume = {11},
	number = {5},
	year = {1997},
	note = {ISI Document Delivery No.: WZ733Times Cited: 7Cited Reference Count: 28Pacifichem 95 Meeting on Safety and Environmental Effects of Organometallics1995HONOLULU, HI},
	month = {May},
	pages = {369-379},
	type = {Proceedings Paper},
	abstract = {The efflux of dimethylarsinic acid (DMA) from liposomes formed from egg phosphatidylcholine (EPC) is increased when tributyltin chloride (TBT) is added to the extraliposomal compartment; however the addition of monobutyltin trichloride (MBT) slows down the efflux. When the liposomes are prepared from EPC and organotin compounds, different mechanisms for DMA efflux seem to operate: TBT-EPC liposomes show a mixture of facilitated and passive diffusion; MBT-EPC liposomes show only passive diffusion. The facilitated diffusion of DMA(-) seems to be stopped by the addition of TBT to the extraliposomal compartment. (C) 1997 by John Wiley \& Sons, Ltd.},
	keywords = {bilayer, DIMETHYLARSINIC ACID, efflux, egg, ERYTHROCYTE, EXCHANGE, facilitated diffusion, LIPOSOMES, membrane modification, monobutyltin, NMR, PHOSPHATIDYLCHOLINE, tributyltin chloride, trichloride},
	isbn = {0268-2605},
	url = {<Go to ISI>://A1997WZ73300003},
	author = {Cullen, W. R. and Herring, F. G. and Nwata, B. U.}
}
@article {3289,
	title = {ARSENIC BIOMETHYLATION BY THE MICROORGANISM APIOTRICHUM HUMICOLA IN THE PRESENCE OF L-METHIONINE-METHYL-D(3)},
	journal = {Applied Organometallic Chemistry},
	volume = {9},
	number = {7},
	year = {1995},
	note = {ISI Document Delivery No.: TG189Times Cited: 15Cited Reference Count: 273rd International Conference on Environmental and Biological Aspects of Main Group Organometals (ICEBAMO 94)SEP, 1994BORDEAUX, FRANCESoc Francaise Chim, Royal Soc Chem, CNRS, EC Measurement \& Testing Program, French Minist Environm, French Minist Res \& Technol, Univ Bordeaux I, Univ Bordeaux II, IFREMER, INRA, Conseil Reg Aquitaine, Lyonnaise Eaux Dumez Water Co., Thermo Jarell Ash, John Wiley \& Sons, Freund Publ, Elsevier Sci Publ},
	month = {Nov},
	pages = {507-515},
	type = {Proceedings Paper},
	abstract = {The microorganism Apiotrichum humicola (previously known as Candida humicola) grown in the presence of either arsenate, arsenite, methyl-arsonic acid or dimethylarsinic acid, produces arsenic-containing metabolites in the growth medium. When L-methionine-methyl-d(3) is added to the cultures, the CD3 label is incorporated intact into the metabolites to a considerable extent to form deuterated dimethylarsenic and trimethylarsenic species, indicating that S-adenosylmethionine, or some related sulphonium compound, is involved in the biological methylation. Conclusive evidence of CD3 incorporation in the arsenicals found in the growth medium was provided by using a specially developed hydride generation-gas chromatography-mass spectrometry system (HG-GC-MS).},
	keywords = {ARSENATE, ARSENITE, CHROMATOGRAPHY MASS SPECTROMETRY, DIMETHYLARSINIC ACID, EXTRACELLULAR, GAS, HYDRIDE GENERATION, HYDRIDE GENERATION GAS, L-METHIONINE-METHYL-D(3), methylarsonic acid, METHYLATION, MICROORGANISM, REDUCTION, S-ADENOSYLMETHIONINE, THIOLS, TRIMETHYLARSINE OXIDE},
	isbn = {0268-2605},
	url = {<Go to ISI>://A1995TG18900002},
	author = {Cullen, W. R. and Li, H. and Pergantis, S. A. and Eigendorf, G. K. and Mosi, A. A.}
}
