DMPS–Arsenic Challenge Test

Aposhian, H. Vasken; Zheng, Bo; Aposhian, Mary M.; Le, X. Chris; Cebrián, Mariano E.; Cullen, William R.; Zakharyan, Roksana; Ma, Meihu; Dart, Richard C.; Zhai, Cheng; Andrewes, Paul; Yip, Luke; O’Malley, Gerald F.; Maiorino, Richard M.; Voorhies, Wayne Van; Healy, Sheila M.; Titcomb, Allison

doi:10.1006/taap.2000.8922

Cited by 118 publications

(30 citation statements)

References 28 publications

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“…These species were observed in human urine when sodium 2,3-dimercapto-1-propane sulfonate was orally administered to humans before collection of their urine samples (22,23). Furthermore, these species are reported to be unstable in solution and are readily oxidized to their pentavalent forms (referred to as DMA and MMA in this study) (22).…”

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confidence: 69%

Development and application of a robust speciation method for determination of six arsenic compounds present in human urine.

Milstein

Essader

Pellizzari

et al. 2003

Environ Health Perspect

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Six arsenic species [arsenate, arsenite, arsenocholine, arsenobetaine, monomethyl arsonic acid, and dimethyl arsinic acid] present in human urine were determined using ion-exchange chromatography combined with inductively coupled plasma mass spectrometry (IC-ICP-MS). Baseline separation was achieved for all six species as well as for the internal standard (potassium hexahydroxy antimonate V) in a single chromatographic run of less than 30 min, using an ammonium carbonate buffer gradient (between 10 and 50 mM) at ambient temperature, in conjunction with cation- and anion-exchange columns in series. The performance of the method was evaluated with respect to linearity, precision, accuracy, and detection limits. This method was applied to determine the concentration of these six arsenic species in human urine samples (n = 251) collected from a population-based exposure assessment survey. Method precision was demonstrated by the analysis of duplicate samples that were prepared over a 2-year analysis period. Total arsenic was also determined for the urine samples using flow injection analysis coupled to ICP-MS. The summed concentration of the arsenic species was compared with the measured arsenic total to demonstrate mass balance.

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mentioning

confidence: 69%

Development and application of a robust speciation method for determination of six arsenic compounds present in human urine.

Milstein

Essader

Pellizzari

et al. 2003

Environ Health Perspect

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“…These trivalent methylated arsenicals, MMA(III) and DMA(III), have been recently confirmed in the urine of humans exposed to arsenic in drinking water [15][16][17][18][19][20]. There has since been increasing interest in the determination of the trivalent methylated arsenicals in biological samples, as this may yield information on the mechanism of arsenic-induced carcinogenicity.…”

Section: Introductionmentioning

confidence: 99%

“…To date, several procedures have been developed and documented for speciation of arsenic [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Of the numerous methods reported, liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) with high sensitivity and accuracy is the most effective for determination of urinary arsenic metabolites [20,[23][24][25][26]28,29].…”

Section: Introductionmentioning

confidence: 99%

Determination of trivalent methylated arsenicals in rat urine by liquid chromatography–inductively coupled plasma mass spectrometry after solvent extraction

Okina

Yoshida

Kuroda

et al. 2004

Journal of Chromatography B

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“…However, recent research has shown that methylated arsenicals that contain As III are important intermediates in the metabolism of inorganic arsenic. Methylated arsenicals that contain As III are found in the urine of individuals who chronically consume drinking water that contains inorganic arsenic and in cells cultured in the presence of arsenite (13)(14)(15)(16)(17)(18). These As III -containing metabolites are more cytotoxic and genotoxic than either arsenate or arsenite (19 -21).…”

mentioning

confidence: 99%

A Novel S-Adenosyl-l-methionine:Arsenic(III) Methyltransferase from Rat Liver Cytosol

Lin

Shi

Nix

et al. 2002

Journal of Biological Chemistry

323

216

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S-Adenosyl-L-methionine (AdoMet):arsenic(III) methyltransferase, purified from liver cytosol of adult male Fischer 344 rats, catalyzes transfer of a methyl group from AdoMet to trivalent arsenicals producing methylated and dimethylated arsenicals. The kinetics of production of methylated arsenicals in reaction mixtures containing enzyme, AdoMet, dithiothreitol, glutathione (GSH), and arsenite are consistent with a scheme in which monomethylated arsenical produced from arsenite is the substrate for a second methylation reaction that yields dimethylated arsenical. The mRNA for this protein predicts a 369-amino acid residue protein (molecular mass 41056) that contains common methyltransferase sequence motifs. Its sequence is similar to Cyt19, a putative methyltransferase, expressed in human and mouse tissues. Reverse transcription-polymerase chain reaction detects S-adenosyl-L-methionine:arsenic(III) methyltransferase mRNA in rat tissues and in HepG2 cells, a human cell line that methylates arsenite and methylarsonous acid. S-Adenosyl-L-methionine:arsenic-(III) methyltransferase mRNA is not detected in UROtsa cells, an immortalized human urothelial cell line that does not methylate arsenite. Because methylation of arsenic is a critical feature of its metabolism, characterization of this enzyme will improve our understanding of this metalloid's metabolism and its actions as a toxin and a carcinogen.In many species, including humans, exposure to inorganic arsenic results in urinary excretion of methylated and dimethylated arsenicals (1-3). Cullen and co-workers (4) summarized the conversion of inorganic arsenic into these methylated products in a reaction scheme which incorporates oxidative methylation and the cycling of arsenic between the pentavalent (As V ) 1 and trivalent (As III ) oxidation states,Because reduction of arsenic to trivalency is a prerequisite for its oxidative methylation, pentavalent arsenicals are reduced by endogenous thiols such as glutathione (GSH) (5, 6) or by As V reductases (7-9). A protein has been purified from rabbit liver cytosol that catalyzes the methylation of both arsenite and methylarsonous acid (10, 11); however, this protein has not been sequenced. These activities are designated arsenite methyltransferase (EC 2.1.1.137) and methylarsonite methyltransferase (EC 2.1.1.138), respectively. This protein (estimated molecular mass 60 kDa) uses S-adenosyl-L-methionine (AdoMet) as the methyl group donor. The methylation of arsenite by this protein is stimulated by a monothiol (GSH) and the methylation of methylarsonous acid is highly stimulated by a dithiol, dithiothreitol (DTT). The methylation of arsenic has been commonly regarded as a mechanism for its detoxification (12). However, recent research has shown that methylated arsenicals that contain As III are important intermediates in the metabolism of inorganic arsenic. Methylated arsenicals that contain As III are found in the urine of individuals who chronically consume drinking water that contains inorganic arsenic and in cells cu...

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DMPS–Arsenic Challenge Test

Cited by 118 publications

References 28 publications

Development and application of a robust speciation method for determination of six arsenic compounds present in human urine.

Development and application of a robust speciation method for determination of six arsenic compounds present in human urine.

Determination of trivalent methylated arsenicals in rat urine by liquid chromatography–inductively coupled plasma mass spectrometry after solvent extraction

A Novel S-Adenosyl-l-methionine:Arsenic(III) Methyltransferase from Rat Liver Cytosol

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