Understanding arsenic metabolism through spectroscopic determination of arsenic in human urine

Brima, Eid I.; Jenkins, Richard O.; Haris, Parvez I.

doi:10.1155/2006/759046

Cited by 16 publications

(6 citation statements)

References 90 publications

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“…It is worth mentioning that previous studies have also reported high levels of AB in urine. 19,33,34 For example, 70% of total urinary As was found as AB in healthy volunteers who refrained from seafood consumption for two days. 19 An explanation for this may be linked to sources of AB in the diet other than seafood.…”

Section: Discussionmentioning

confidence: 99%

Effect of fasting on the pattern of urinary arsenic excretion

et al. 2007

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Millions of people in some of the poorest regions of the world are exposed to high levels of arsenic through drinking contaminated water. It has been reported that development of cancer caused by arsenic exposure in such populations is dependent on dietary and nutritional factors which can modulate arsenic metabolism. Many people in arsenic exposed regions of Bangladesh and India practice fasting for at least one month every year when they refrain from consumption of food and fluid during daylight hours. How such practices may modulate arsenic metabolism has not been previously investigated. This study investigated this issue by determining total arsenic and its species in urine samples from a group of 29 unexposed volunteers at the beginning of the fasting and at the end of approximately 12 h of fasting period. Inductively coupled plasma mass spectrometry (ICP-MS) and high performance liquid chromatography (HPLC) coupled with ICP-MS was used to measure the total arsenic and arsenic speciation in the urine samples, respectively. The mean total levels of arsenic at the beginning of fasting (18.3 microg g(-1) creatinine) and at the end of approximately 12 h of fasting (17.7 microg g(-1) creatinine) did not differ significantly (p > 0.05). However, the percentages of urinary arsenic as the methylated arsenic species methylarsonate (MA) were found to be significantly different (p < 0.05) and this species was observed more frequently at the end of fasting, although its overall concentration was similar. There were no significant differences (p > 0.05) in both the concentrations and percentages of other urinary arsenic species detected, namely arsenobetaine (AB) and dimethylarsinate (DMA). Arsenite (As(III)) and arsenate (As(V)) were also analyzed, but were not detected. We conclude that fasting for a period of 12 h results in a significant increase in the percentage of urinary arsenic as MA, and its frequency of detection in the volunteers at the end of the fasting period is almost nine fold higher. This suggests that metabolism of arsenic is altered by fasting.

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Section: Discussionmentioning

confidence: 99%

Effect of fasting on the pattern of urinary arsenic excretion

et al. 2007

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“…An alternative means of extrusion of arsenite from cells is methylation, with subsequent cellular export of the methylated species and excretion via urine [29]; exposure to inorganic arsenic leads to the appearance of high concentrations of dimethylarsinic acid [DMA(V)] and to a lesser extent methylarsonic acid [MA(V)], in the urine [30]. Compared with the corresponding trivalent methylated species, these pentavalent species are much more water soluble, much less reactive and have much lower affinity for biological tissue; factors that favour preferential excretion of the pentavalent forms.…”

Section: Mammalian Biomethylation Of Arsenicmentioning

confidence: 99%

Biomethylation of Arsenic, Antimony and Bismuth

Jenkins

2010

Biological Chemistry of Arsenic, Antimony and Bismuth

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Biomethylation of metals or metalloids refers to the process whereby living organisms cause direct linkage of methyl groups to the metal(loid)s through enzymatic transfer of a preformed methyl group. The attachment of a methyl group to a metal(loid) changes the chemical and physical properties of the element, which in turn influences its mobility, geological cycling and toxicity. Biomethylation of the following metal(loid)s have been definitively established, although for most very little is known about the biological mechanism involved: Cd, Hg, Tl, Ge, Sn, Pb, As, Sb, Bi, Se and Te. The biological systems responsible for metal(loid) biomethylation are almost exclusively microorganisms. Anaerobic prokaryotes, operating in anoxic environments such as sediments from environmental waters and landfill sites, are major biocatalysts of metal(loid) biomethylation in the natural environment. Methylmetal(loid)s have also been shown to occur in soils from disparate locations and some aerobic and facultatively anaerobic bacteria, fungi and lower algae have been shown to be capable of metal(loid) biomethylation. Although higher organisms have not been shown to biomethylate true metals, methyl derivatives of some metalloids (including those of Se and As) are formed in a wide range of higher animals and plants.Over the past decade there has been a diversification of methods for the detection and measurement of organometallic compounds. Generally, this has been accompanied by improvements in reliability of detection and measurement of organometal(loid)s at low

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“…The reviewers drew particular attention to sample preparation, reproducibility of determination and intraindividual variability. Arguably more important was the review by Brima and colleagues 142 of the spectroscopic techniques currently used to determine As species in urine for understanding As metabolism and toxicity. The reviewers highlighted the advantages and disadvantages of the different instrumental techniques described.…”

Section: Antimonymentioning

confidence: 99%