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Udensi UK, Cohly HHP, Graham-Evans BE, Ndebele K, Garcia-Reyero N, Nanduri B, Tchounwou PB, Isokpehi RD. Aberrantly Expressed Genes in HaCaT Keratinocytes Chronically Exposed to Arsenic Trioxide. Biomark Insights 2011; 6:7-16. [PMID: 21461292 PMCID: PMC3065373 DOI: 10.4137/bmi.s6383] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Inorganic arsenic is a known environmental toxicant and carcinogen of global public health concern. Arsenic is genotoxic and cytotoxic to human keratinocytes. However, the biological pathways perturbed in keratinocytes by low chronic dose inorganic arsenic are not completely understood. The objective of the investigation was to discover the mechanism of arsenic carcinogenicity in human epidermal keratinocytes. We hypothesize that a combined strategy of DNA microarray, qRT-PCR and gene function annotation will identify aberrantly expressed genes in HaCaT keratinocyte cell line after chronic treatment with arsenic trioxide. Microarray data analysis identified 14 up-regulated genes and 21 down-regulated genes in response to arsenic trioxide. The expression of 4 up-regulated genes and 1 down-regulated gene were confirmed by qRT-PCR. The up-regulated genes were AKR1C3 (Aldo-Keto Reductase family 1, member C3), IGFL1 (Insulin Growth Factor-Like family member 1), IL1R2 (Interleukin 1 Receptor, type 2), and TNFSF18 (Tumor Necrosis Factor [ligand] SuperFamily, member 18) and down-regulated gene was RGS2 (Regulator of G-protein Signaling 2). The observed over expression of TNFSF18 (167 fold) coupled with moderate expression of IGFL1 (3.1 fold), IL1R2 (5.9 fold) and AKR1C3 (9.2 fold) with a decreased RGS2 (2.0 fold) suggests that chronic arsenic exposure could produce sustained levels of TNF with modulation by an IL-1 analogue resulting in chronic immunologic insult. A concomitant decrease in growth inhibiting gene (RGS2) and increase in AKR1C3 may contribute to chronic inflammation leading to metaplasia, which may eventually lead to carcinogenicity in the skin keratinocytes. Also, increased expression of IGFL1 may trigger cancer development and progression in HaCaT keratinocytes.
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Affiliation(s)
- Udensi K Udensi
- RCMI-Center for Environmental Health, College of Science, Engineering and Technology, Jackson State University, Jackson MS 39217, USA
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152
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Sorlini S, Gialdini F. Conventional oxidation treatments for the removal of arsenic with chlorine dioxide, hypochlorite, potassium permanganate and monochloramine. WATER RESEARCH 2010; 44:5653-9. [PMID: 20638704 DOI: 10.1016/j.watres.2010.06.032] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 06/10/2010] [Accepted: 06/14/2010] [Indexed: 05/20/2023]
Abstract
Arsenic is widespread in soils, water and air. In natural water the main forms are arsenite (As(III)) and arsenate (As(V)). The consumption of water containing high concentration of arsenic produces serious effects on human health, like skin and lung cancer. In Italy, Legislative Decree 2001/31 reduced the limit of arsenic from 50 to 10 μg/L, in agreement with the European Directive 98/83/EC. As consequence, many drinking water treatment plant companies needed to upgrade the existing plants where arsenic was previously removed or to build up new plants for arsenic removal when this contaminant was not previously a critical parameter. Arsenic removal from water may occur through the precipitation with iron or aluminum salts, adsorption on iron hydroxide or granular activated alumina (AA), reverse osmosis and ion exchange (IE). Some of the above techniques, especially precipitation, adsorption with AA and IE, can reach good arsenic removal yields only if arsenic is oxidized. The aim of the present work is to investigate the efficiency of the oxidation of As(III) by means of four conventional oxidants (chlorine dioxide, sodium hypochlorite, potassium permanganate and monochloramine) with different test conditions: different type of water (demineralised and real water), different pH values (5.7-6-7 and 8) and different doses of chemicals. The arsenic oxidation yields were excellent with potassium permanganate, very good with hypochlorite and low with monochloramine. These results were observed both on demineralised and real water for all the tested reagents with the exception of chlorine dioxide that showed a better arsenic oxidation on real groundwater than demineralised water.
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Affiliation(s)
- Sabrina Sorlini
- Department of Civil Engineering, Architecture, Land and Environment, University of Brescia, via Branze, 43, 25123 Brescia, Italy.
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153
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Yoon IH, Moon DH, Kim KW, Lee KY, Lee JH, Kim MG. Mechanism for the stabilization/solidification of arsenic-contaminated soils with Portland cement and cement kiln dust. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2010; 91:2322-2328. [PMID: 20643499 DOI: 10.1016/j.jenvman.2010.06.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 05/24/2010] [Accepted: 06/21/2010] [Indexed: 05/29/2023]
Abstract
In this study, the mechanism for the stabilization/solidification (S/S) of arsenic (As)-contaminated soils with Portland cement (PC), and cement kiln dust (CKD) using 1 N HCl extraction fluid, X-ray powder diffraction (XRPD), X-ray absorption near edge structure (XANES) and Extended X-ray absorption fine structure (EXAFS) spectroscopy was investigated. The degree of As immobilization after stabilization was assessed using a 1 N HCl extraction on the basis of the Korean Standard Test (KST). After 1 day of curing with 30 wt% PC and 7 days of curing with 50 wt% CKD, the concentration of As leached from the amended soils was less than the Korean countermeasure standard (3 mg L(-1)). The As concentrations in the leachate treated with PC and CKD were significantly decreased at pH > 3, indicating that pH had a prevailing influence on As mobility. XRPD results indicated that calcium arsenite (Ca-As-O) and sodium calcium arsenate hydrate (NaCaAsO(4).7.5H(2)O) were present in the PC- and CKD-treated slurries as the key phases responsible for As(III) and As(V) immobilization, respectively. The XANES spectroscopy confirmed that the As(III) and As(V) oxidation states of the PC and CKD slurry samples were consistent with the speciated forms in the crystals identified by XRPD. EXAFS spectroscopy showed As-Ca bonding in the As(III)-PC and As(III)-CKD slurries. The main mechanism for the immobilization of As-contaminated soils with PC and CKD was strongly associated with the bonding between As(III) or As(V) and Ca.
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Affiliation(s)
- In-Ho Yoon
- Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712, Republic of Korea
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154
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Isokpehi RD, Cohly HHP, Anyanwu MN, Rajnarayanan RV, Tchounwou PB, Udensi UK, Graham-Evans BE. Candidate single nucleotide polymorphism markers for arsenic responsiveness of protein targets. Bioinform Biol Insights 2010; 4:99-111. [PMID: 20981267 PMCID: PMC2964045 DOI: 10.4137/bbi.s5498] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Arsenic is a toxic metalloid that causes skin cancer and binds to cysteine residues—a property that could be used to infer arsenic responsiveness of a target protein. Non-synonymous Single Nucleotide Polymorphisms (nsSNPs) result in amino acid substitutions and may alter arsenic binding with cysteine residues. Thus, the objective of this investigation was to identify and analyze nsSNPs that lead to substitutions to or from cysteine residues as an indication of increased or decreased arsenic responsiveness. We hypothesize that integration of data on molecular impacts of nsSNPs and arsenic-gene relationships will identify nsSNPs that could serve as arsenic responsiveness markers. We have analyzed functional and structural impacts data for 5,811 nsSNPs linked to 1,224 arsenic-annotated genes. In addition to the identified candidate nsSNPs for increased or reduced arsenic responsiveness, we observed i) a nsSNP that results in the breakage of a disulfide bond, as candidate marker for reduced arsenic responsiveness of KLK7, a secreted serine protease participate in normal shedding of the skin; and ii) 6 pairs of vicinal cysteines in KLK7 protein that could be binding sites for arsenic. In summary, our analysis identified non-synonymous SNPs that could be used to evaluate responsiveness of a protein target to arsenic. In particular, an epidermal expressed serine protease with crucial function in normal skin physiology was prioritized on the basis of abundance of vicinal cysteines for further research on arsenic-induced keratinocyte carcinogenesis.
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Affiliation(s)
- Raphael D Isokpehi
- RCMI-Center for Environmental Health, College of Science, Engineering and Technology, Jackson State University, Jackson, Mississippi 39217, USA
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155
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Chowdhury R, Chatterjee R, Giri AK, Mandal C, Chaudhuri K. Arsenic-induced cell proliferation is associated with enhanced ROS generation, Erk signaling and CyclinA expression. Toxicol Lett 2010; 198:263-71. [DOI: 10.1016/j.toxlet.2010.07.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 07/07/2010] [Indexed: 10/19/2022]
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156
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Liu P, Wang CN, Song XY, Yu YF, Wu YN. Dietary intake of arsenic by children and adults from Jinhu area of China. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2010; 27:1128-35. [DOI: 10.1080/19440041003753466] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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157
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Effect of metals on β-actin and total protein synthesis in cultured human intestinal epithelial cells. J Pharmacol Toxicol Methods 2010; 63:47-58. [PMID: 20452446 DOI: 10.1016/j.vascn.2010.04.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 02/08/2010] [Accepted: 04/27/2010] [Indexed: 11/20/2022]
Abstract
INTRODUCTION As an important structural protein, β-actin is associated with anchoring of tight junctions (TJs) to the cell scaffold. Caco-2 cells, an immortal intestinal epithelial cell line, rely on β-actin to form intact monolayers with high transepithelial electrical resistance in cell culture inserts. METHODS We examined the effect of six metals on expression of β-actin mRNA and β-actin synthesis, on total and net production of newly synthesized proteins, on paracellular transport of TJ markers, and on cell viability in confluent monolayers. [(3)H]-glycine and [(3)H]-tyrosine were used as indicators of newly synthesized proteins in the absence or presence of increasing concentrations of arsenic, cadmium, copper, manganese, mercury and nickel. The monolayers were exposed to 24-h single exposures as well as continuous daily repeated doses of metals for 48-h and 96-h. RESULTS Results suggest that decreases in newly synthesized proteins, in which β-actin represents about 10%, correlated with 2- to 5-fold higher expression of β-actin mRNA for the higher concentrations of metals. Interestingly, IC(50)s calculated for each chemical for 24-h acute and 48- and 96-h repeated dosing experiments, using the MTT viability assay and paracellular permeability markers, decreased newly synthesized and total proteins to 10% and 40% of control, respectively. DISCUSSION Overall, the results indicate that, at equivalent concentrations, the metals affect β-actin mRNA and newly synthesized proteins before cell viability and paracellular permeability are compromised. Consequently the results help in elucidating mechanisms of metal cytotoxicity that lead to understanding the relationship between tight junction integrity, paracellular transport, and cell viability.
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158
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The effects of arsenic trioxide on DNA synthesis and genotoxicity in human colon cancer cells. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2010; 7:2018-32. [PMID: 20623008 PMCID: PMC2898033 DOI: 10.3390/ijerph7052018] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 02/26/2010] [Accepted: 04/03/2010] [Indexed: 01/22/2023]
Abstract
Colon cancer is the third leading cause of cancer-related deaths worldwide. Recent studies in our laboratory have demonstrated that arsenic trioxide is cytotoxic in human colon cancer (HT-29), lung (A549) and breast (MCF-7) carcinoma cells. The purpose of the present study is to investigate the effects of arsenic trioxide on DNA synthesis and the possible genotoxic effects on human colon cancer cells. HT-29 cells were cultured according to standard protocol, followed by exposure to various doses (0, 2, 4, 6, 8, 10, and 12 μg/mL) of arsenic trioxide for 24 h. The proliferative response (DNA synthesis) to arsenic trioxide was assessed by [3H]thymidine incorporation. The genotoxic effects of arsenic-induced DNA damage in a human colon cancer cell line was evaluated by the alkaline single cell gel electrophoresis. Results indicated that arsenic trioxide affected DNA synthesis in HT-29 cells in a biphasic manner; showing a slight but not significant increase in cell proliferation at lower levels of exposure (2, 4 and 6 μg/mL) followed by a significant inhibition of cell proliferation at higher doses (i.e., 8 and 10 μg/mL). The study also confirmed that arsenic trioxide exposure caused genotoxicity as revealed by the significant increase in DNA damage, comet tail-lengths, and tail moment when compared to non-exposed cells. Results of the [3H]thymidine incorporation assay and comet assay revealed that exposure to arsenic trioxide affected DNA synthesis and exhibited genotoxic effects in human colon cancer cells.
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159
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Sinicropi MS, Amantea D, Caruso A, Saturnino C. Chemical and biological properties of toxic metals and use of chelating agents for the pharmacological treatment of metal poisoning. Arch Toxicol 2010; 84:501-20. [PMID: 20386880 DOI: 10.1007/s00204-010-0544-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 04/01/2010] [Indexed: 10/19/2022]
Abstract
Exposure to toxic metals is a well-known problem in industrialized countries. Metals interfere with a number of physiological processes, including central nervous system (CNS), haematopoietic, hepatic and renal functions. In the evaluation of the toxicity of a particular metal it is crucial to consider many parameters: chemical forms (elemental, organic or inorganic), binding capability, presence of specific proteins that selectively bind metals, etc. Medical treatment of acute and chronic metal toxicity is provided by chelating agents, namely organic compounds capable of interacting with metal ions to form structures called chelates. The present review attempts to provide updated information about the mechanisms, the cellular targets and the effects of toxic metals.
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160
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Abstract
BACKGROUND/PURPOSE The electropharmacological effect of arsenic trioxide (As2O3) is unknown. The present study investigated the effects of As2O3 on spontaneous neuronal impulse activity. METHODS Intracellular recordings and the two-electrode voltage clamp method were used to study the effect of As2O3 on the RP4 neuron, the number 4 neuron in the right partial ganglion of the giant African snail (Achatina fulica Ferussac). RESULTS The RP4 neuron generated spontaneous action potentials, which were affected by As2O3 in a concentration-dependent manner. Extracellular application of 1 or 3 mM As2O3 decreased the frequency of spontaneously generated action potentials. At 10 mM, As2O3 first depolarized and then elicited irreversible bursts of potential (BoPs) at 60 minutes after administration. At 30 mM, As2O3 depolarized the resting membrane potential and abolished the spontaneous action potentials. The BoPs elicited by 10mM As2O3 were blocked when neurons were pretreated with phospholipase C (PLC) inhibitors (10 microM U73122 or 3mM neomycin). The BoPs elicited by As2O3 remained unchanged in the presence of KT5720, verapamil, or calcium replacement solution. Voltage-clamp studies revealed that 10mM As2O3 decreased the fast inward current and had no effect on the steady-state outward current of the neuron. CONCLUSION As2O3 at 10 mM elicits BoPs in central snail neurons and this effect may relate to the PLC activity of the neuron, rather than protein kinase A activity, or calcium influxes of the neuron. As2O3 at higher concentration irreversibly abolishes the spontaneous action potentials of the neuron.
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161
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Song X, Geng Z, Li C, Hu X, Wang Z. Transition metal ions and selenite modulate the methylation of arsenite by the recombinant human arsenic (+3 oxidation state) methyltransferase (hAS3MT). J Inorg Biochem 2010; 104:541-50. [PMID: 20129672 DOI: 10.1016/j.jinorgbio.2010.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 01/08/2010] [Accepted: 01/11/2010] [Indexed: 12/15/2022]
Abstract
This report demonstrates that transition metal ions and selenite affect the arsenite methylation by the recombinant human arsenic (+3 oxidation state) methyltransferase (hAS3MT) in vitro. Co(2+), Mn(2+), and Zn(2+) inhibited the arsenite methylation by hAS3MT in a concentration-dependent manner and the kinetics indicated Co(2+) and Mn(2+) to be mixed (competitive and non-competitive) inhibitors while Zn(2+) to be a competitive inhibitor. However, only a high concentration of Fe(2+) could restrain the methylation. UV-visible, CD and fluorescence spectroscopy were used to study the interactions between the metal ions above and hAS3MT. Further studies showed that neither superoxide anion nor hydrogen peroxide was involved in the transition metal ion or selenite inhibition of hAS3MT activity. The inhibition of arsenite methylating activity of hAS3MT by selenite was reversed by 2mM DTT (dithiothreitol) but neither by cysteine nor by beta-mercaptoethanol. Whereas, besides DTT, cysteine can also prevent the inhibition of hAS3MT activity by Co(2+), Mn(2+), and Zn(2+). Free Cys residues were involved in the interactions of transition metal ions or selenite with hAS3MT. It is proposed that the inhibitory effect of the ions (Co(2+), Mn(2+), and Zn(2+)) or selenite on hAS3MT activity might be via the interactions of them with free Cys residues in hAS3MT to form inactive protein adducts.
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Affiliation(s)
- Xiaoli Song
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China
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162
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Virag P, Brie I, Postescu ID, Perde-Schrepler M, Fischer-Fodor E, Soritau O, Irimie A, Cernea V. Comparative study of two evaluation methods for the genotoxic effects of environmental heavy metals on normal cells. Toxicol Ind Health 2009; 25:253-8. [PMID: 19651795 DOI: 10.1177/0748233709103411] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Genetic modifications caused by chronic exposure to low levels of toxic metals may activate stress-signaling pathways, thus increasing cancer incidence among affected individuals. The aim of this study was to evaluate the relationship between exposure to heavy metals and the incidence of chromosomal aberrations and DNA lesions in a chronically exposed population by using specific biomarkers. The study included 156 subjects divided into two major groups: exposed individuals (in a heavy metal contaminated region, Maramures, Romania) and non-exposed population, as control group (Cluj, Romania). We compared the results of two cytogenetic methods for the detection and quantification of DNA lesions and chromosomal aberrations in normal human cells: Single Cell Gel Electrophoresis or Comet assay and Cytokinesis Block Micronucleus assay. The methods were performed on lymphocytes isolated from whole blood in density gradient. The basal DNA lesions and chromosomal aberrations were evaluated, as well as the repair capacity of the supplementary lesions induced by genotoxic agents such as ionizing radiations. Our results showed a great interindividual variability in the basal level of the DNA lesions and chromosomal aberrations, between and within the groups, the most affected being the heavy metals-exposed groups. Non-exposed subjects from rural area Cluj appeared to be more susceptible to the induction of supplementary DNA lesions and chromosomal aberrations by irradiation. The most efficient repair capacity of the radio-induced DNA lesions was observed in the non-exposed Cluj urban group. Both cytogenetic assays (as tools for detection of DNA lesions and chromosomal aberrations) may be used in human biomonitoring studies as indicators of early biological effects induced by exposure to heavy metals.
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Affiliation(s)
- P Virag
- "Prof. Dr. I. Chiricuta" Cancer Institute, Cluj-Napoca, Romania.
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163
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Williams AB, Ayejuyo OO, Ogunyale AF. Trace metal levels in fruit juices and carbonated beverages in Nigeria. ENVIRONMENTAL MONITORING AND ASSESSMENT 2009; 156:303-306. [PMID: 18704729 DOI: 10.1007/s10661-008-0485-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2007] [Accepted: 07/23/2008] [Indexed: 05/26/2023]
Abstract
Trace metal levels in selected fruit juices and carbonated beverages purchased in Lagos, Nigeria were determined using atomic absorption spectrophotometer (Unicam model 969) equipped with SOLAAR 32 windows software. Fruit juices analysed were grape, pineapple, apple, orange, lemon juices and their brand names were used. Some carbonated drinks were also evaluated for metal levels. Trace metals investigated were Cr, Cu, Pb, Mn, Ni, Zn, Sn, Fe, Cd and Co. Trace metal contents of fruit juices were found to be more than the metallic contents of carbonated beverages. Pb level in the fruit juices ranged from 0.08 to 0.57 mg/l but was not detected in the carbonated drinks. Concentrations of Pb in lemon juice and Mn in pineapple juice were relatively high. Cd and Co were not detected in the selected juices and beverages. Additionally, Pb, Cu, Cr and Fe were not detected in canned beverages but were present in bottled beverages. However, the metal levels of selected fruit juices and carbonated beverages were within permissible levels except for Mn in pineapple juice and Pb in lemon juice.
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Affiliation(s)
- Akan B Williams
- Department of Chemistry, Covenant University, P M B 1023, Ota, Ogun State, Nigeria.
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164
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Chang JS, Gu MB, Kim KW. Effect of arsenic on p53 mutation and occurrence of teratogenic salamanders: their potential as ecological indicators for arsenic contamination. CHEMOSPHERE 2009; 75:948-954. [PMID: 19203779 DOI: 10.1016/j.chemosphere.2009.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 12/27/2008] [Accepted: 01/02/2009] [Indexed: 05/27/2023]
Abstract
The p53 mutation in salamanders can be used as an indicator of arsenic contamination. The influence of arsenic exposure was studied on mutation of tumor suppressor gene in salamanders collected from several As-contaminated mine areas in Korea. Salamander eggs and larvae were exposed to arsenic in a toxicity test, and teratogenic salamanders found in heavy metal- and As-contaminated water from As-Bi mines were evaluated using PCR-SSCP to determine if they would be useful as an ecological indicator species. Changes in amino acids were shown to have occurred as a result of an arsenic-accumulating event that occurred after the DNA damage. In addition, both of the Hynobius leechii exposed groups were primarily affected by forms of skin damage, changes in the lateral tail/dorsal flexure and/or abnormality teratogenesis. Single-base sense mutation in codons 346 (AAG: Lys to ATG: Met), 224 (TTT: Phe to TTA: Leu), 211 (ATG: Met to AAG: Lys), 244 (TTT: Phe to TTTG: insertion), 245 (Glu GAG to Gln CAG) and 249 (TGT Cys to TGA stop) of the p53 gene were simultaneously found in mutated salamanders. Based on the results of our data illustrating the effect of arsenic exposure on the p53 mutation of salamanders in arsenic-contaminated mine areas, these mutated salamanders can be used as potential ecological indicators in the arsenic-contaminated ecosystems.
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Affiliation(s)
- Jin-Soo Chang
- Arsenic Geoenvironment Laboratory (National Research Laboratory), Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), Buk-gu, Gwangju, Republic of Korea
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165
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Li G, Liu Y, Wang Y, Liao L. The molecular resonance fluorescence method for determination of arsenic in hair samples. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2009; 72:811-815. [PMID: 19138554 DOI: 10.1016/j.saa.2008.11.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 11/11/2008] [Accepted: 11/15/2008] [Indexed: 05/27/2023]
Abstract
A molecular resonance fluorescence quenching method for the determination of arsenic was proposed. The method is based on the quenching effect of As (V) on the molecular resonance fluorescence of Rhodamine B (RhB) in sulfuric acid medium and in the presence of molybdate and PVA. The influences of acidity, chemical and manifold variables on the sensitivity were studied. At the optimized conditions, the linear range for the determination of arsenic was 2.0x10(-3)-0.12microgml(-1) with the detection limit of 1.20x10(-9)gml(-1). The relative standard deviations for the eleven replicate determinations of 0.006microgml(-1) and 0.060microgml(-1) of arsenic were 1.12% and 1.61%, respectively. The proposed method was applied successfully for the determination of trace arsenic in hair samples with the recoveries of 94.8-104.6%.
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Affiliation(s)
- Guirong Li
- University of South China, Hengyang, PR China.
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166
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Khan NI, Owens G, Bruce D, Naidu R. Human arsenic exposure and risk assessment at the landscape level: a review. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2009; 31 Suppl 1:143-166. [PMID: 19172401 DOI: 10.1007/s10653-008-9240-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 07/16/2008] [Accepted: 09/17/2008] [Indexed: 05/27/2023]
Abstract
Groundwater contaminated with arsenic (As), when extensively used for irrigation, causes potentially long term detrimental effects to the landscape. Such contamination can also directly affect human health when irrigated crops are primarily used for human consumption. Therefore, a large number of humans are potentially at risk worldwide due to daily As exposure. Numerous previous studies have been severely limited by small sample sizes which are not reliably extrapolated to large populations or landscapes. Human As exposure and risk assessment are no longer simple assessments limited to a few food samples from a small area. The focus of more recent studies has been to perform risk assessment at the landscape level involving the use of biomarkers to identify and quantify appropriate health problems and large surveys of human dietary patterns, supported by analytical testing of food, to quantify exposure. This approach generates large amounts of data from a wide variety of sources and geographic information system (GIS) techniques have been used widely to integrate the various spatial, demographic, social, field, and laboratory measured datasets. With the current worldwide shift in emphasis from qualitative to quantitative risk assessment, it is likely that future research efforts will be directed towards the integration of GIS, statistics, chemistry, and other dynamic models within a common platform to quantify human health risk at the landscape level. In this paper we review the present and likely future trends of human As exposure and GIS application in risk assessment at the landscape level.
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Affiliation(s)
- Nasreen Islam Khan
- Centre for Risk Assessment and Remediation (CERAR), University of South Australia, Mawson Lakes, SA, Australia.
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167
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Williams G, West JM, Koch I, Reimer KJ, Snow ET. Arsenic speciation in the freshwater crayfish, Cherax destructor Clark. THE SCIENCE OF THE TOTAL ENVIRONMENT 2009; 407:2650-8. [PMID: 19223061 DOI: 10.1016/j.scitotenv.2008.12.065] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 12/19/2008] [Accepted: 12/19/2008] [Indexed: 05/05/2023]
Abstract
Arsenic is a proven carcinogen that is found in the soil in gold mining regions at concentrations that can be thousands of times greater than gold. During mining arsenic is released into the environment, easily entering surrounding water bodies. The yabby (Cherax destructor) is a common freshwater crustacean native to Australia's central and eastern regions. Increasing aquaculture and export of these animals has led us to question the effects of mine contamination on the yabbies themselves and to assess any potential risks to consumers. This study determined the species of arsenic present in a number of organs from the yabby. Several arsenic contaminated dam sites in the goldfields of western Victoria were sampled for yabby populations. Yabbies from these sites were collected and analysed for arsenic speciation using high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). Results showed that type of exposure influenced which arsenic species was present in each organ, and that as arsenic exposure increased the prevalence of inorganic arsenic species, mostly As(V), within the tissues increased. The bioaccessibility of the arsenic present in the abdominal muscle (the edible portion for humans) of the yabbies was assessed. It was found that the majority of the bioaccessible arsenic was present as inorganic As(III) and As(V).
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Affiliation(s)
- Gemma Williams
- School of Life and Environmental Sciences, Deakin University, 221 Burwood, Hwy, Burwood, Vic, Australia
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168
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Zhu YG, Rosen BP. Perspectives for genetic engineering for the phytoremediation of arsenic-contaminated environments: from imagination to reality? Curr Opin Biotechnol 2009; 20:220-4. [PMID: 19303764 PMCID: PMC4578631 DOI: 10.1016/j.copbio.2009.02.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Revised: 02/12/2009] [Accepted: 02/20/2009] [Indexed: 10/21/2022]
Abstract
Phytoremediation to clean up arsenic-contaminated environments has been widely hailed as environmentally friendly and cost effective, and genetic engineering is believed to improve the efficiency and versatility of phytoremediation. Successful genetic engineering requires the thorough understanding of the mechanisms involved in arsenic tolerance and accumulation by natural plant species. Key mechanisms include arsenate reduction, arsenic sequestration in vacuoles of root or shoot, arsenic loading to the xylem, and volatilization through the leaves. Key advances include the identification of arsenic (As) translocation from root to shoot in the As hyperaccumulator, Pteris vittata, and the characterization of related key genes from hyperaccumulator and nonaccumulators. In this paper we have proposed three pathways for genetic engineering: arsenic sequestration in the root, hyperaccumulation of arsenic in aboveground tissues, and phytovolatilization.
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Affiliation(s)
- Yong-Guan Zhu
- Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
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169
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Li D, Lu C, Wang J, Hu W, Cao Z, Sun D, Xia H, Ma X. Developmental mechanisms of arsenite toxicity in zebrafish (Danio rerio) embryos. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2009; 91:229-37. [PMID: 19110324 DOI: 10.1016/j.aquatox.2008.11.007] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 11/08/2008] [Accepted: 11/10/2008] [Indexed: 05/06/2023]
Abstract
Arsenic usually accumulates in soil, water and airborne particles, from which it is taken up by various organisms. Exposure to arsenic through food and drinking water is a major public health problem affecting some countries. At present there are limited laboratory data on the effects of arsenic exposure on early embryonic development and the mechanisms behind its toxicity. In this study, we used zebrafish as a model system to investigate the effects of arsenite on early development. Zebrafish embryos were exposed to a range of sodium arsenite concentrations (0-10.0mM) between 4 and 120h post-fertilization (hpf). Survival and early development of the embryos were not obviously influenced by arsenite concentrations below 0.5mM. However, embryos exposed to higher concentrations (0.5-10.0mM) displayed reduced survival and abnormal development including delayed hatching, retarded growth and changed morphology. Alterations in neural development included weak tactile responses to light (2.0-5.0mM, 30hpf), malformation of the spinal cord and disordered motor axon projections (2.0mM, 48hpf). Abnormal cardiac function was observed as bradycardia (0.5-2.0mM, 60hpf) and altered ventricular shape (2.0mM, 48hpf). Furthermore, altered cell proliferation (2.0mM, 24hpf) and apoptosis status (2.0mM, 24 and 48hpf), as well as abnormal genomic DNA methylation patterning (2.0mM, 24 and 48hpf) were detected in the arsenite-treated embryos. All of these indicate a possible relationship between arsenic exposure and developmental failure in early embryogenesis. Our studies suggest that the negative effects of arsenic on vertebrate embryogenesis are substantial.
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Affiliation(s)
- Dan Li
- Department of Genetics, National Research Institute for Family Planning, Beijing, China
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170
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Yoon IH, Chang JS, Lee JH, Kim KW. Arsenite oxidation by Alcaligenes sp. strain RS-19 isolated from arsenic-contaminated mines in the Republic of Korea. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2009; 31:109-117. [PMID: 18642094 DOI: 10.1007/s10653-008-9170-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Accepted: 04/02/2008] [Indexed: 05/26/2023]
Abstract
Arsenite [As(III)]-oxidizing bacteria play important roles in reducing arsenic [As] toxicity and mobility in As-contaminated areas. As-resistant bacteria were isolated from the soils of two abandoned mines in the Republic of Korea. The isolated bacteria showed relatively high resistances to As(III) up to 26 mM. The PCR-based 16S rRNA analysis revealed that the isolated As-resistant bacteria were close relatives to Serratia marcescensa, Pseudomonas putida, Pantoea agglomerans, and Alcaligenes sp. Among the five As-resistant bacterial isolates, Alcaligenes sp. strain RS-19 showed the highest As(III)-oxidizing activity in batch tests, completely oxidizing 1 mM of As(III) to As(V) within 40 h during heterotrophic growth. This study suggests that the indigenous bacteria have evolved to retain the ability to resist toxic As in the As-contaminated environments and moreover to convert the species to a less toxic form [e.g., from As(III) to As(V)] and also contribute the biogeochemical cycling of As by being involved in speciation of As.
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Affiliation(s)
- In-Ho Yoon
- Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju, Republic of Korea
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171
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Effects of selenium on the structure and function of recombinant human S-adenosyl-L-methionine dependent arsenic (+3 oxidation state) methyltransferase in E. coli. J Biol Inorg Chem 2009; 14:485-96. [PMID: 19159958 DOI: 10.1007/s00775-008-0464-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2008] [Accepted: 12/26/2008] [Indexed: 10/21/2022]
Abstract
The effects of Se(IV) on the structure and function of recombinant human arsenic (+3 oxidation state) methyltransferase (AS3MT) purified from the cytoplasm of Escherichia coli were studied. The coding region of human AS3MT complementary DNA was amplified from total RNA extracted from HepG2 cell by reverse transcription PCR. Soluble and active human AS3MT was expressed in the E. coli with a Trx fusion tag under a lower induction temperature of 25 degrees C. Spectra (UV-vis, circular dichroism, and fluorescence) were first used to probe the interaction of Se(IV) and recombinant human AS3MT and the structure-function relationship of the enzyme. The recombinant human AS3MT had a secondary structure of 29.0% alpha-helix, 23.9% beta-pleated sheet, 17.9% beta-turn, and 29.2% random coil. When Se(IV) was added, the content of the alpha-helix did not change, but that of the beta-pleated sheet increased remarkably in the conformation of recombinant human AS3MT. Se(IV) inhibited the enzymatic methylation of inorganic As(III) in a concentration-dependent manner. The IC(50) value for Se(IV) was 2.38 muM. Double-reciprocal (1/V vs. 1/[inorganic As(III)]) plots showed Se(IV) to be a noncompetitive inhibitor of the methylation of inorganic As(III) by recombinant human AS3MT with a K (i) value of 2.61 muM. We hypothesized that Se(IV) interacts with the sulfhydryl group of cysteine(s) in the structural residues rather than the cysteines of the active site (Cys156 and Cys206). When Se(IV) was combined with cysteine(s) in the structural residues, the conformation of recombinant human AS3MT changed and the enzymatic activity decreased. Considering the quenching of tryptophan fluorescence, Cys72 and/or Cys226 are deduced to be primary targets for Se(IV).
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172
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Li G, Liu Y, Wang Y. Determination of Arsenic in Hair by Resonance Rayleigh Scattering Method with Iodine Green–Molybdate System. ANAL LETT 2009. [DOI: 10.1080/00032710802568614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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173
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Han YY, Weissfeld JL, Davis DL, Talbott EO. Arsenic levels in ground water and cancer incidence in Idaho: an ecologic study. Int Arch Occup Environ Health 2008; 82:843-9. [PMID: 18941772 DOI: 10.1007/s00420-008-0362-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Accepted: 09/29/2008] [Indexed: 11/29/2022]
Abstract
PURPOSE Long-term exposure to arsenic above 50 microg/L in drinking water has been related to multiple types of cancers. Few epidemiologic studies conducted in the US have detected an association between regional exposures below this level in drinking water and corresponding cancer occurrence rates. This county-level ecologic study evaluates arsenic levels in ground water and its association with targeted cancer incidence in Idaho, where some regions have been found to contain higher arsenic levels. METHODS Using cancer incidence data (1991-2005) from the Cancer Data Registry of Idaho and arsenic data (1991-2005) from the Idaho Department of Environmental Quality, we calculated the age-adjusted incidence rate for cancers of the urinary bladder, kidney and renal pelvis, liver and bile duct, lung and bronchus, non-Hodgkin's lymphoma (NHL), and all malignant cancers according to arsenic levels in ground water. Multivariate regression analysis was applied to evaluate the relationship between arsenic levels in ground water and cancer incidence. RESULTS For males, but not for females, age-adjusted incidence for lung cancer and all malignant cancers was significantly higher in the intermediate arsenic counties (2-9 microg/L, n = 16) and the high arsenic counties (>or=10 microg/L, n = 5) compared to the low arsenic counties (<2.0 microg/L, n = 23). When adjusted for race, gender, population density, smoking and body mass index (BMI), no relationship was found between arsenic levels in ground water and cancer incidence. CONCLUSIONS In this ecological design, exposure to low-level arsenic in ground water is not associated with cancer incidence when adjusting for salient variables. For populations residing in southwestern Idaho, where arsenic has been found to exceed 10 microg/L in ground water, individual risk assessment is required in order to determine whether there is a link between long-term arsenic exposure at these levels and cancer risk.
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Affiliation(s)
- Yueh-Ying Han
- Center for Environmental Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA.
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174
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Davis AP, Murphy CG, Rosenstein MC, Wiegers TC, Mattingly CJ. The Comparative Toxicogenomics Database facilitates identification and understanding of chemical-gene-disease associations: arsenic as a case study. BMC Med Genomics 2008; 1:48. [PMID: 18845002 PMCID: PMC2576347 DOI: 10.1186/1755-8794-1-48] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Accepted: 10/09/2008] [Indexed: 12/02/2022] Open
Abstract
Background The etiology of many chronic diseases involves interactions between environmental factors and genes that modulate physiological processes. Understanding interactions between environmental chemicals and genes/proteins may provide insights into the mechanisms of chemical actions, disease susceptibility, toxicity, and therapeutic drug interactions. The Comparative Toxicogenomics Database (CTD; ) provides these insights by curating and integrating data describing relationships between chemicals, genes/proteins, and human diseases. To illustrate the scope and application of CTD, we present an analysis of curated data for the chemical arsenic. Arsenic represents a major global environmental health threat and is associated with many diseases. The mechanisms by which arsenic modulates these diseases are not well understood. Methods Curated interactions between arsenic compounds and genes were downloaded using export and batch query tools at CTD. The list of genes was analyzed for molecular interactions, Gene Ontology (GO) terms, KEGG pathway annotations, and inferred disease relationships. Results CTD contains curated data from the published literature describing 2,738 molecular interactions between 21 different arsenic compounds and 1,456 genes and proteins. Analysis of these genes and proteins provide insight into the biological functions and molecular networks that are affected by exposure to arsenic, including stress response, apoptosis, cell cycle, and specific protein signaling pathways. Integrating arsenic-gene data with gene-disease data yields a list of diseases that may be associated with arsenic exposure and genes that may explain this association. Conclusion CTD data integration and curation strategies yield insight into the actions of environmental chemicals and provide a basis for developing hypotheses about the molecular mechanisms underlying the etiology of environmental diseases. While many reports describe the molecular response to arsenic, CTD integrates these data with additional curated data sets that facilitate construction of chemical-gene-disease networks and provide the groundwork for investigating the molecular basis of arsenic-associated diseases or toxicity. The analysis reported here is extensible to any environmental chemical or therapeutic drug.
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Affiliation(s)
- Allan P Davis
- Department of Bioinformatics, The Mount Desert Island Biological Laboratory, Salisbury Cove, Maine 04672 USA.
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175
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Cowen S, Duggal M, Hoang T, Al-Abadleh HA. Vibrational spectroscopic characterization of some environmentally important organoarsenicals — A guide for understanding the nature of their surface complexes. CAN J CHEM 2008. [DOI: 10.1139/v08-102] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Organoarsenicals are found in the environment from the biomethylation of inorganic arsenic compounds and from anthropogenic sources. It is clear that organoarsenicals pose a health and an environmental risk due to their potential cycling to the most toxic forms of arsenic as a result of redox activity in soils and natural waters. The environmental fate of arsenic compounds depends to a large extent on the surface interactions with geosorbents, mainly minerals and organic matter. Hence, elucidating the nature of surface complexes is important in understanding binding mechanisms and thermodynamics. In this paper, we report the vibrational spectra of a number of organoarsenicals in the aqueous and solid phases using attenuated total internal reflectance Fourier transform infrared (ATR-FTIR), transmission FTIR, and Raman spectroscopies. Analysis of the aqueous phase spectra revealed that for completely deprotonated anions, increasing the organic substituents on the AsOx moiety results in increasing the frequency of v(AsOx), whereas the opposite trend is observed for completely protonated molecules. Analysis of solid phase spectra showed that incorporation of water molecules in the crystalline structure and extensive hydrogen bonding with neighboring molecules significantly affect As–O bond lengths and hence frequencies of v(AsOx). Results are discussed in the context of identifying geometry of organoarsenicals surface complexes in situ using the ATR-FTIR technique.Key words: ATR-FTIR, organoarsenicals; oxyanion adsorption, arsenate, in situ spectroscopy.
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176
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Oti D, Trotz M. Characterization and adsorption of arsenate and selenite onto Kemiron. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2008; 43:1184-1191. [PMID: 18584434 DOI: 10.1080/10934520802171741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Kemiron, a commercially available, porous iron oxide sorbent was evaluated in batch systems for arsenate (As(V)) and selenite (Se(IV)) removal from aqueous solutions as a function of pH, ionic strength, and particle size (< 38 micro m and between 250 and 425 micro m). BET surface area of Kemiron is 39.8 m(2)/g and Electron dispersive spectroscopy (EDS) studies found Kemiron to be 40.37% iron and 42.25% oxygen by mass. Langmuir isotherms best described the As(V) and Se(IV) removal at pH 7 with maximum adsorption capacity of 82 mg/g and 52 mg/g respectively. As(V) and Se(IV) sorption decreased as pH increased and both anions were unaffected by sodium nitrate (NaNO(3)) background electrolyte. As(V) sorption was not affected in surface water samples from the Hillsborough River. Batch kinetic models of the experimental data on the 250 to 425 micro m particle size yielded mass transfer coefficients of 0.0008 min(-1) and 0.009 min(-1) for As(V) and Se(IV) respectively.
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Affiliation(s)
- Douglas Oti
- Department of Civil and Environmental Engineering, University of South Florida, Tampa, Florida 33620, USA.
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177
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Endo H, Sugioka Y, Nakagi Y, Saijo Y, Yoshida T. A novel role of the NRF2 transcription factor in the regulation of arsenite-mediated keratin 16 gene expression in human keratinocytes. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:873-879. [PMID: 18629308 PMCID: PMC2453154 DOI: 10.1289/ehp.10696] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Accepted: 03/06/2008] [Indexed: 05/26/2023]
Abstract
BACKGROUND Inorganic sodium arsenite (iAs) is a ubiquitous environmental contaminant and is associated with an increased risk of skin hyperkeratosis and cancer. OBJECTIVES We investigated the molecular mechanisms underlying the regulation of the keratin 16 (K16) gene by iAs in the human keratinocyte cell line HaCaT. METHODS We performed reverse transcriptase polymerase chain reaction, luciferase assays, Western blots, and electrophoretic mobility shift assays to determine the transcriptional regulation of the K16 gene by iAs. We used gene overexpression approaches to elucidate the nuclear factor erythroid-derived 2 related factor 2 (NRF2) involved in the K16 induction. RESULTS iAs induced the mRNA and protein expression of K16. We also found that the expression of K16 was transcriptionally induced by iAs through activator protein-1-like sites and an antioxidant response element (ARE) in its gene promoter region. Treatment with iAs also enhanced the production and translocation of the NRF2 transcription factor, an ARE-binding protein, into the nucleus without modification of its mRNA expression. In addition, iAs elongated the half-life of the NRF2 protein. When overexpressed in HaCaT cells, NRF2 was also directly involved in not only the up-regulation of the detoxification gene thioredoxin but also K16 gene expression. CONCLUSIONS Our data clearly indicate that the K16 gene is a novel target of NRF2. Furthermore, our findings also suggest that NRF2 has opposing roles in the cell--in the activation of detoxification pathways and in promoting the development of skin disorders.
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Affiliation(s)
| | | | | | | | - Takahiko Yoshida
- Address correspondence to T. Yoshida, Department of Health Science, Asahikawa Medical College, E2–1-1–1, Midorigaoka, Asahikawa, Hokkaido, 078–8510 Japan. Telephone: 81-166-68-2400/2402. Fax: 81-166-68-2409. E-mail:
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178
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Maduabuchi JMU, Adigba EO, Nzegwu CN, Oragwu CI, Okonkwo IP, Orisakwe OE. Arsenic and chromium in canned and non-canned beverages in Nigeria: a potential public health concern. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2008; 4:28-33. [PMID: 17431312 PMCID: PMC3719956 DOI: 10.3390/ijerph2007010005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Numerous studies have described environmental exposure of humans to heavy metals in African populations. Little is known about the exposure to heavy metal toxins from processed or unprocessed foods consumed in Africa, and no data exists on the food concentrations of arsenic and chromium, which are potential carcinogens and systemic toxicants. This study determined the concentrations of arsenic and chromium in beverages and fruit drinks commonly sold in Nigeria. Fifty samples of commonly consumed canned and non-canned beverages (imported and locally manufactured) purchased in Nigeria were digested in nitric acid and analyzed by atomic absorption spectrophotometry (AAS). 33.3% of the canned beverages had arsenic levels that exceeded the maximum contaminant level (MCL) of 0.01 mg/L set by U.S. EPA while 55.2% of non-canned beverages had their arsenic levels exceeding the MCL. The arsenic concentrations ranged from 0.003 to 0.161 mg/L for the canned and 0.002 to 0.261 mg/l for the non-canned beverages. Whereas 68.9% of the non-canned beverages showed chromium levels that exceeded the US EPA's MCL of 0.10 mg/L, 76.2% of the canned beverages had chromium levels that were greater than the MCL. The concentration range of total chromium in the canned beverages was 0.04 to 0.59 mg/L and 0.01 to 0.55 mg/L for the non-canned beverages. The sources of arsenic and chromium in the commercially available beverages are unclear and merit further investigation. This preliminary study highlights the need to study the toxicological implications of chronic low-level exposure to heavy metals from African markets.
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179
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Baastrup R, Sørensen M, Balstrøm T, Frederiksen K, Larsen CL, Tjønneland A, Overvad K, Raaschou-Nielsen O. Arsenic in drinking-water and risk for cancer in Denmark. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:231-7. [PMID: 18288323 PMCID: PMC2235208 DOI: 10.1289/ehp.10623] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Accepted: 11/23/2007] [Indexed: 05/02/2023]
Abstract
BACKGROUND Arsenic is a well-known carcinogen, which is often found in drinking-water. Epidemiologic studies have shown increased cancer risks among individuals exposed to high concentrations of arsenic in drinking-water, whereas studies of the carcinogenic effect of low doses have had inconsistent results. OBJECTIVE Our aim was to determine if exposure to low levels of arsenic in drinking-water in Denmark is associated with an increased risk for cancer. METHODS The study was based on a prospective Danish cohort of 57,053 persons in the Copenhagen and Aarhus areas. Cancer cases were identified in the Danish Cancer Registry, and the Danish civil registration system was used to trace and geocode residential addresses of the cohort members. We used a geographic information system to link addresses with water supply areas, then estimated individual exposure to arsenic using residential addresses back to 1970. Average exposure for the cohort ranged between 0.05 and 25.3 microg/L (mean = 1.2 microg/L). Cox's regression models were used to analyze possible relationships between arsenic and cancer. RESULTS We found no significant association between exposure to arsenic and risk for cancers of the lung, bladder, liver, kidney, prostate, or colorectum, or melanoma skin cancer; however, the risk for non-melanoma skin cancer decreased with increasing exposure (incidence rate ratio = 0.88/microg/L average exposure; 95% confidence interval, 0.84-0.94). Results adjusted for enrollment area showed no association with non-melanoma skin cancer. CONCLUSIONS The results indicate that exposure to low doses of arsenic might be associated with a reduced risk for skin cancer.
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Affiliation(s)
- Rikke Baastrup
- Danish Cancer Society, Institute of Cancer Epidemiology, Strandboulevarden 49, Copenhagen, Denmark.
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180
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Salnikow K, Zhitkovich A. Genetic and epigenetic mechanisms in metal carcinogenesis and cocarcinogenesis: nickel, arsenic, and chromium. Chem Res Toxicol 2008; 21:28-44. [PMID: 17970581 PMCID: PMC2602826 DOI: 10.1021/tx700198a] [Citation(s) in RCA: 566] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chronic exposure to nickel(II), chromium(VI), or inorganic arsenic (iAs) has long been known to increase cancer incidence among affected individuals. Recent epidemiological studies have found that carcinogenic risks associated with chromate and iAs exposures were substantially higher than previously thought, which led to major revisions of the federal standards regulating ambient and drinking water levels. Genotoxic effects of Cr(VI) and iAs are strongly influenced by their intracellular metabolism, which creates several reactive intermediates and byproducts. Toxic metals are capable of potent and surprisingly selective activation of stress-signaling pathways, which are known to contribute to the development of human cancers. Depending on the metal, ascorbate (vitamin C) has been found to act either as a strong enhancer or suppressor of toxic responses in human cells. In addition to genetic damage via both oxidative and nonoxidative (DNA adducts) mechanisms, metals can also cause significant changes in DNA methylation and histone modifications, leading to epigenetic silencing or reactivation of gene expression. In vitro genotoxicity experiments and recent animal carcinogenicity studies provided strong support for the idea that metals can act as cocarcinogens in combination with nonmetal carcinogens. Cocarcinogenic and comutagenic effects of metals are likely to stem from their ability to interfere with DNA repair processes. Overall, metal carcinogenesis appears to require the formation of specific metal complexes, chromosomal damage, and activation of signal transduction pathways promoting survival and expansion of genetically/epigenetically altered cells.
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Affiliation(s)
- Konstantin Salnikow
- Konstantin Salnikow, National Cancer Institute, Bldg. 538, Room 205 E, Frederick, MD 21702, Phone: 301-846-5623, Fax: 301-846-5946, E-mail:
| | - Anatoly Zhitkovich
- Anatoly Zhitkovich, Brown University, Center for Genomics and Proteomics, Department of Pathology and Laboratory Medicine, 70 Ship Street, Providence RI 02912, Phone: 401-863-2912, Fax: 401-863-9008, E-mail:
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181
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Yedjou CG, Tchounwou PB. In-vitro cytotoxic and genotoxic effects of arsenic trioxide on human leukemia (HL-60) cells using the MTT and alkaline single cell gel electrophoresis (Comet) assays. Mol Cell Biochem 2007; 301:123-30. [PMID: 17216127 PMCID: PMC3760965 DOI: 10.1007/s11010-006-9403-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2006] [Accepted: 12/14/2006] [Indexed: 10/23/2022]
Abstract
Although arsenic trioxide (ATO) has been the subject of toxicological research, in vitro cytotoxicity and genotoxicity studies using relevant cell models and uniform methodology are not well elucidated. Hence, the aim of the present study was to evaluate the cytotoxicity and genotoxicity induced by ATO in a human leukemia (HL-60) cell line using the MTT [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and alkaline single cell gel electrophoresis (Comet) assays, respectively. HL-60 cells were treated with different doses of ATO for 24 h prior to cytogenetic assessment. Data obtained from the MTT assay indicated that ATO significantly (P < 0.05) reduced the viability of HL-60 cells in a dose-dependent manner, showing a LD(50) value of 6.4 +/- 0.6 microg/mL. Data generated from the comet assay also indicated a significant dose-dependent increase in DNA damage in HL-60 cells associated with ATO exposure. We observed a significant increase (P < 0.05) in comet tail-length, tail arm and tail moment, as well as in percentages of DNA cleavage at all doses tested, showing an evidence of ATO-induced genotoxic damage in HL-60 cells. This study confirms that the comet assay is a sensitive and effective method to detect DNA damage caused by heavy metals like arsenic. Taken together, our findings suggest that ATO exposure significantly (P < 0.05) reduces cellular viability and induces DNA damage in HL-60 cells as assessed by MTT and alkaline single cell gel electrophoresis assays, respectively.
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182
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Jiang HY, Jiang L, Wek RC. The eukaryotic initiation factor-2 kinase pathway facilitates differential GADD45a expression in response to environmental stress. J Biol Chem 2006; 282:3755-65. [PMID: 17170114 DOI: 10.1074/jbc.m606461200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphorylation of eukaryotic initiation factor-2 (eIF2) regulates general and gene-specific translation in response to diverse environmental stresses. Central to gene expression induced by eIF2 phosphorylation is the preferential translation of ATF4, a basic zipper transcription activator. Phosphorylation of eIF2 and its attendant induction of ATF4 can lead to different patterns of gene expression depending on the environmental stress. This is of fundamental importance because eIF2 kinases can induce the expression of genes involved in survival as well as in apoptosis. In this report, we explore the molecular basis for why there can be differential expression of GADD45a, a stress-responsive protein that regulates genome stability, apoptosis, and immune responses. We find that whereas ATF4 is required for GADD45a transcription during many different environmental stresses, GADD45a protein accumulates only during a limited number of stress arrangements. The basis for this difference between measurable GADD45a mRNA and protein lies in the observation that GADD45a protein is labile. Those stress agents that enhance ATF4-directed GADD45a transcription and impede the turnover of GADD45a protein by blocking ubiquitin/proteasome-mediated degradation elevate GADD45a protein levels. By comparison, those stress arrangements that trigger ATF4 levels and GADD45a transcription, but do not perturb the proteasome pathway, only elevate GADD45a mRNA levels. This study highlights the molecular mechanisms by which environmental stresses can differentially control central regulatory proteins targeted by the eIF2 kinase pathway.
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Affiliation(s)
- Hao-Yuan Jiang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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183
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Desheng Q, Niya Z. Effect of Arsanilic Acid on Performance and Residual of Arsenic in Tissue of Japanese Laying Quail. Poult Sci 2006; 85:2097-100. [PMID: 17135662 DOI: 10.1093/ps/85.12.2097] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Three hundred seventy-five 63-d-old laying Japanese quail were randomly distributed into 3 experimental groups (125 birds per group) and fed the following diets for 40 d, with 30 d on the experimental diets, followed by a 10-d withdrawal period: 1) control; 2) 50 mg of 4-arsanilic acid/kg of feed; and 3) 100 mg of 4-arsanilic acid/kg of feed. Each treatment consisted of 5 replicates of 25 birds. During the first 30 d of the experiment, all eggs were recorded, collected, individually weighed daily, and feed consumption was determined every 10 d. Five quail from each replicate in the experiment were euthanized by cervical dislocation at 0, 30, 35, and 40 d. Tissue samples from the liver, kidney, heart, gizzard, and the muscle on the breast and leg were collected for determination of As residue. The feces and eggs at 0, 30, 35, and 40 d of the experiment were selected for determination of As. Results showed that dietary inclusion of 50 and 100 mg/kg of 4-arsanilic acid significantly improved feed utilization and egg production, but the concentration of As in the tissues and feces in groups fed 4-arsanilic acid was higher than in control group. The results of the present study demonstrate that the use of organic As compounds as feed additives in diet is a matter for argument.
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Affiliation(s)
- Q Desheng
- College of Animal Science, Huazhong Agricultural University, Wuhan 430070, China.
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184
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Diawara MM, Litt JS, Unis D, Alfonso N, Martinez L, Crock JG, Smith DB, Carsella J. Arsenic, cadmium, lead, and mercury in surface soils, Pueblo, Colorado: implications for population health risk. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2006; 28:297-315. [PMID: 16752202 DOI: 10.1007/s10653-005-9000-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2004] [Accepted: 06/27/2005] [Indexed: 05/02/2023]
Abstract
Decades of intensive industrial and agricultural practices as well as rapid urbanization have left communities like Pueblo, Colorado facing potential health threats from pollution of its soils, air, water and food supply. To address such concerns about environmental contamination, we conducted an urban geochemical study of the city of Pueblo to offer insights into the potential chemical hazards in soil and inform priorities for future health studies and population interventions aimed at reducing exposures to inorganic substances. The current study characterizes the environmental landscape of Pueblo in terms of heavy metals, and relates this to population distributions. Soil was sampled within the city along transects and analyzed for arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb). We also profiled Pueblo's communities in terms of their socioeconomic status and demographics. ArcGIS 9.0 was used to perform exploratory spatial data analysis and generate community profiles and prediction maps. The topsoil in Pueblo contains more As, Cd, Hg and Pb than national soil averages, although average Hg content in Pueblo was within reported baseline ranges. The highest levels of As concentrations ranged between 56.6 and 66.5 ppm. Lead concentrations exceeded 300 ppm in several of Pueblo's residential communities. Elevated levels of lead are concentrated in low-income Hispanic and African-American communities. Areas of excessively high Cd concentration exist around Pueblo, including low income and minority communities, raising additional health and environmental justice concerns. Although the distribution patterns vary by element and may reflect both industrial and non-industrial sources, the study confirms that there is environmental contamination around Pueblo and underscores the need for a comprehensive public health approach to address environmental threats in urban communities.
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Affiliation(s)
- Moussa M Diawara
- Department of Biology, Colorado State University--Pueblo, 2200 Bonforte Blvd, Pueblo, Colorado 81001, USA.
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185
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Hall M, Chen Y, Ahsan H, Slavkovich V, van Geen A, Parvez F, Graziano J. Blood arsenic as a biomarker of arsenic exposure: Results from a prospective study. Toxicology 2006; 225:225-33. [PMID: 16860454 DOI: 10.1016/j.tox.2006.06.010] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 05/25/2006] [Accepted: 06/07/2006] [Indexed: 11/23/2022]
Abstract
Exposure to arsenic (As)-contaminated drinking water affects millions of people worldwide. Arsenic exposure is associated with skin lesions, skin, lung, kidney and liver cancers, neurologic and cardiovascular effects. Past studies involving biomarkers of As exposure have typically examined urinary As (UAs) (adjusted for urinary creatinine), hair or toenail As, but not blood As (BAs) since blood concentrations are exceedingly low and are not detectable by conventional atomic absorption spectrophotometric techniques. In a case-cohort analysis of 303 newly diagnosed cases of skin lesions, and 849 subcohort members randomly selected from 8092 participants in the health effects of as longitudinal study (HEALS) in Araihazar, Bangladesh, we measured blood, urine and water As concentrations, and examined their associations with each other, and with the risk for skin lesions. BAs concentrations were highly correlated with creatinine-adjusted UAs concentrations (r=0.85) and with water As (WAs) (r=0.75). We observed consistent dose-response relationships between the risk of skin lesions and all the measures of As exposure. Rate ratios (RRs) for skin lesions by quintile of As exposure, adjusted for age and gender, revealed that the two highest quintiles were significantly related to an increased risk of skin lesions for each measure of exposure: BAs, UAs, WAs and a time-weighted water As variable. This prospective study confirms the increased risk of skin lesions in relation to As concentrations in blood, urine and water and also establishes that BAs is a useful biomarker of As exposure in this study population.
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Affiliation(s)
- Marni Hall
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University Medical Center, 60 Haven Avenue B1, New York, NY 10032, USA
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186
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Patlolla AK, Tchounwou PB. Serum acetyl cholinesterase as a biomarker of arsenic induced neurotoxicity in sprague-dawley rats. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2006; 2:80-3. [PMID: 16705804 PMCID: PMC3814700 DOI: 10.3390/ijerph2005010080] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Arsenic is an environmental toxicant, and one of the major mechanisms by which it exerts its toxic effect is through an impairment of cellular respiration by inhibition of various mitochondrial enzymes, and the uncoupling of oxidative phosphorylation. Most toxicity of arsenic results from its ability to interact with sulfhydryl groups of proteins and enzymes, and to substitute phosphorus in a variety of biochemical reactions. Most toxicity of arsenic results from its ability to interact with sulfhydryl groups of proteins and enzymes, and to substitute phosphorus in a variety of biochemical reactions. Recent studies have pointed out that arsenic toxicity is associated with the formation of reactive oxygen species, which may cause severe injury/damage to the nervous system. The main objective of this study was to conduct biochemical analysis to determine the effect of arsenic trioxide on the activity of acetyl cholinesterase; a critical important nervous system enzyme that hydrolyzes the neurotransmitter acetylcholine. Four groups of six male rats each weighing an average 60 +/- 2 g were used in this study. Arsenic trioxide was intraperitoneally administered to the rats at the doses of 5, 10, 15, 20mg/kg body weight (BW), one dose per 24 hour given for five days. A control group was also made of 6 animals injected with distilled water without chemical. Following anaesthesia, blood specimens were immediately collected using heparinized syringes, and acetyl cholinesterase detection and quantification were performed in serum samples by spectrophotometry. Arsenic trioxide exposure significantly decreased the activity of cholinesterase in the Sprague-Dawley rats. Acetyl cholinesterase activities of 6895 +/- 822, 5697 +/- 468, 5069 +/- 624, 4054 +/- 980, and 3158 +/- 648 U/L were recorded for 0, 5, 10, 15, and 20 mg/kg, respectively; indicating a gradual decrease in acetyl cholinesterase activity with increasing doses of arsenic. These findings indicate that acetyl cholinesterase is a candidate biomarker for arsenic-induced neurotoxicity in Sprague-Dawley rats.
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Affiliation(s)
- Anita K. Patlolla
- Molecular Toxicology Research Laboratory, NIH-Center for Environmental Health, College of Science, Engineering, and Technology, Jackson State University, Jackson, MS, USA
| | - Paul B. Tchounwou
- Molecular Toxicology Research Laboratory, NIH-Center for Environmental Health, College of Science, Engineering, and Technology, Jackson State University, Jackson, MS, USA
- Correspondence to Dr. Paul B. Tchounwou.
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187
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Graham-Evans B, Cohly HHP, Yu H, Tchounwou PB. Arsenic-induced genotoxic and cytotoxic effects in human keratinocytes, melanocytes and dendritic cells. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2006; 1:83-9. [PMID: 16696182 DOI: 10.3390/ijerph2004020083] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Arsenical keratosis and skin cancer are among the most common health effects associated with acute and chronic exposures to arsenic. This study examines the acute and chronic dose-responses of arsenic in established human cell lines using keratinocytes (HaCaT), melanocytes (CRL1675) and dendritic cells (THP-1 + A23187). Chronic conditions were established by treating the three cell lines with at least 8 passages in 0.2 microg/mL arsenic trioxide. Cytotoxicity was assessed using the fluorescein diacetate assay after 72 hrs of exposure. Single cell gel electrophoresis (Comet assay) was used to measure DNA damage. Acute exposure to arsenic had LD10 and LD25 values of 0.38 microg/mL and 3.0 microg/mL for keratinocytes; 0.19 microg/mL and 0.38 microg/mL for melanocytes; and 0.38 microg/mL and 0.75 microg/mL for dendritic cells. Cytotoxicity assays for chronically exposed cells resulted in LD10, and LD25 values of 0.4 microg/mL and 0.8 microg/mL for keratinocytes; 0.10 microg/mL and 0.20 microg/mL for melanocytes; and 0.10 microg/mL and 1.0 microg/mL for dendritic cells. The Comet assay showed that arsenic was highly genotoxic to the three cell lines. No significant differences (p > 0.05) in DNA cleavage were observed between acute and chronic exposures. In acute exposure arsenic genotoxicity was more severe with dendritic cells while melanocytes were more sensitive to arsenic cytotoxicity. Similarly, chronically exposed dendritic cells showed the maximum genotoxic damage while melanocytes were more sensitive to arsenic cytotoxicity. In conclusion, this research shows that arsenic is dermatotoxic, showing a high degree of genotoxicity and cytotoxicity to skin cells.
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Affiliation(s)
- Barbara Graham-Evans
- Molecular Toxicology Research Laboratory, NIH-Center for Environmental Health, Jackson State University, Jackson, MS 39217, USA
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188
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Wood TC, Salavagionne OE, Mukherjee B, Wang L, Klumpp AF, Thomae BA, Eckloff BW, Schaid DJ, Wieben ED, Weinshilboum RM. Human arsenic methyltransferase (AS3MT) pharmacogenetics: gene resequencing and functional genomics studies. J Biol Chem 2006; 281:7364-73. [PMID: 16407288 DOI: 10.1074/jbc.m512227200] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Arsenic contaminates ground water worldwide. Methylation is an important reaction in the biotransformation of arsenic. We set out to study the pharmacogenetics of human arsenic methyltransferase (AS3MT, previously CYT19). After cloning the human AS3MT cDNA, we annotated the human gene and resequenced its 5'-flanking region, exons, and splice junctions using 60 DNA samples from African-American (AA) and 60 samples from Caucasian-American (CA) subjects. We observed 26 single nucleotide polymorphisms (SNPs), including 3 non-synonymous cSNPs, as well as a variable number of tandem repeats in exon 1 within an area encoding the cDNA 5'-untranslated region. The nonsynonymous cSNPs included T860C (M287T) with frequencies of 10.8 and 10% in AA and CA subjects, respectively, as well as C517T (A173W) in one AA and C917T (T306I) in one CA sample. Haplotype analysis showed that Ile(306) was linked to Thr(287), so this double variant allozyme was also studied functionally. After expression in COS-1 cells and correction for transfection efficiency, the Trp(173) allozyme displayed 31%, Thr(287) 350%, Ile(306) 4.8%, and Thr(287)/Ile(306) 6.2% of the activity of the wild type (WT) allozyme, with 20, 190, 4.4, and 7.9% of the level of WT immunoreactive protein, respectively. Apparent K(m) values for S-adenosyl-l-methionine were 4.6, 3.1, and 11 mum for WT, Trp(173), and Thr(287) allozymes, with K(m) values for sodium arsenite with the same allozymes of 11.8, 8.9, and 4.5mum. The Ile(306) and Thr(287)/Ile(306) allozymes expressed too little activity for inclusion in the substrate kinetic studies. Expression of reporter gene constructs for the 5'-flanking region and the variable number of tandem repeats in the 5'-untranslated region demonstrated cell line-dependent variation in reporter gene expression, with shorter repeats associated with increased transcription in HepG2 cells. These results raise the possibility that inherited variation in AS3MT may contribute to variation in arsenic metabolism and, perhaps, arsenic-dependent carcinogenesis in humans.
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Affiliation(s)
- Thomas C Wood
- Division of Clinical Pharmacology, Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
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189
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Patlolla AK, Tchounwou PB. Cytogenetic evaluation of arsenic trioxide toxicity in Sprague-Dawley rats. Mutat Res 2005; 587:126-33. [PMID: 16213187 DOI: 10.1016/j.mrgentox.2005.08.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2004] [Revised: 08/12/2005] [Accepted: 08/18/2005] [Indexed: 11/24/2022]
Abstract
Acute exposure to arsenic trioxide has been reported to induce death and/or multiple organ damage with symptoms including nausea, vomiting, diarrhea, gastrointestinal hemorrhage, cerebral edema, tachycardia, dysrhythmias and hypovolemic shock. Its toxic effects are due to its ability to bind to sulfhydryl groups of proteins and to inhibit energy production. Although the chronic exposure to arsenic trioxide has been linked to various types of cancer, such as skin, liver, lung, bladder and kidney neoplasms, studies of its carcinogenic potential in animals have not been conclusive. In this study, we investigated the genotoxic potential of arsenic trioxide in bone-marrow cells obtained from Sprague-Dawley rats; using chromosomal aberrations (CA), mitotic index (MI) and micronuclei (MN) formation as the toxicological endpoints. Four groups of six male rats each, weighing approximately 60+/-2 g per rat, were injected intraperitoneally, once a day for 5 days with doses of 5, 10, 15 and 20 mg/kg body weight (BW) of arsenic trioxide dissolved in distilled water. A control group was also made of six animals injected with distilled water without chemical. All the animals were sacrificed at the end of the treatment period. Chromosome and micronuclei preparation was obtained from bone-marrow cells following standard protocols. Arsenic trioxide exposure significantly increased the number of structural chromosomal aberrations, the frequency of micronucleated cells and decreased the mitotic index in treated groups when compared with the control group. Our results demonstrate that arsenic trioxide has a clastogenic/genotoxic potential as measured by the bone-marrow CA and MN tests in Sprague-Dawley rats.
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Affiliation(s)
- Anita K Patlolla
- Molecular Toxicology Research Laboratory, NIH - Center for Environmental Health, College of Science, Engineering, and Technology, Jackson State University, Jackson, MS, USA
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190
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191
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Lucchini R, Albini E, Benedetti L, Alessio L. Neurobehavioral science in hazard identification and risk assessment of neurotoxic agents--what are the requirements for further development? Int Arch Occup Environ Health 2005; 78:427-37. [PMID: 15895244 DOI: 10.1007/s00420-005-0607-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Accepted: 01/17/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES Modern neurobehavioral methods find useful application in research into the early effects of exposure to neurotoxic agents in the environment. This paper briefly describes the history and evolution of neurobehavioral toxicology, reviews some current trends in research in this specific discipline and identifies the most important needs and challenges to be addressed in future studies. METHODS All published literature was considered, including ad hoc meeting reports. Further information was obtained directly from experts in the field. RESULTS The number of studies (including those in occupational, environmental and pediatric exposure) using neurobehavioral evaluation is constantly increasing. Regulatory agencies are using scientific data obtained through neurobehavioral assessment, which includes other areas such as neurosensory toxicology. However, further development of this discipline is facing a number of problems and issues. Three major areas that deserve further attention have been identified: (1) specific technical issues regarding testing development, (2) epidemiological issues regarding the study design, including the need for meta-analysis/multi-center studies and for longitudinal observation, and statistical issues regarding the most adequate models for the analysis and treatment of complex neurobehavioral datasets, and (3) the need for scientific consensus on the significance of adverse effects identified with neurobehavioral methods. CONCLUSIONS The importance of neurobehavioral toxicology in the evaluation of mechanisms of action and for preventive purposes is progressively growing. Further development is needed for the advancement of this discipline through collaboration between experts from different fields.
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Affiliation(s)
- Roberto Lucchini
- Institute of Occupational Health, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy.
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192
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White PA, Claxton LD. Mutagens in contaminated soil: a review. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2004; 567:227-345. [PMID: 15572286 DOI: 10.1016/j.mrrev.2004.09.003] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The intentional and accidental discharges of toxic pollutants into the lithosphere results in soil contamination. In some cases (e.g., wood preserving wastes, coal-tar, airborne combustion by-products), the contaminated soil constitutes a genotoxic hazard. This work is a comprehensive review of published information on soil mutagenicity. In total, 1312 assessments of genotoxic activity from 118 works were examined. The majority of the assessments (37.6%) employed the Salmonella mutagenicity test with strains TA98 and/or TA100. An additional 37.6% of the assessments employed a variety of plant species (e.g., Tradescantia clone 4430, Vicia faba, Zea mays, Allium cepa) to assess mutagenic activity. The compiled data on Salmonella mutagenicity indicates significant differences (p<0.0001) in mean potency (revertents per gram dry weight) between industrial, urban, and rural/agricultural sites. Additional analyses showed significant empirical relationships between S9-activated TA98 mutagenicity and soil polycyclic aromatic hydrocarbon (PAH) concentration (r2=0.19 to 0.25, p<0.0001), and between direct-acting TA98 mutagenicity and soil dinitropyrene (DNP) concentration (r2=0.87, p<0.0001). The plant assay data revealed excellent response ranges and significant differences between heavily contaminated, industrial, rural/agricultural, and reference sites, for the anaphase aberration in Allium cepa (direct soil contact) and the waxy locus mutation assay in Zea mays (direct soil contact). The Tradescantia assays appeared to be less responsive, particularly for exposures to aqueous soil leachates. Additional data analyses showed empirical relationships between anaphase aberrations in Allium, or mutations in Arabidopsis, and the 137Cs contamination of soils. Induction of micronuclei in Tradescantia is significantly related to the soil concentration of several metals (e.g., Sb, Cu, Cr, As, Pb, Cd, Ni, Zn). Review of published remediation exercises showed effective removal of genotoxic petrochemical wastes within one year. Remediation of more refractory genotoxic material (e.g., explosives, creosote) frequently showed increases in mutagenic hazard that remained for extended periods. Despite substantial contamination and mutagenic hazards, the risk of adverse effect (e.g., mutation, cancer) in humans or terrestrial biota is difficult to quantify.
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Affiliation(s)
- Paul A White
- Mutagenesis Section, Safe Environments Program, Health Canada, Tunney's Pasture 0803A, Ottawa, Ont., Canada K1A 0L2.
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