The Experts below are selected from a list of 1635 Experts worldwide ranked by ideXlab platform
Makoto Umeda - One of the best experts on this subject based on the ideXlab platform.
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Inorganic arsenic compounds and methylated metabolites induce morphological transformation in two-stage BALB/c 3T3 cell assay and inhibit metabolic cooperation in V79 cell assay.
Toxicological Sciences, 2005Co-Authors: Toshiyuki Tsuchiya, Masanori Ando, Toshiko Tanaka-kagawa, Hideto Jinno, Kazunori Sakimoto, Hiroshi Tokunaga, Makoto UmedaAbstract:: We have performed two-stage transformation assay using BALB/c 3T3 cells to determine initiating and promoting activities of diSodium Arsenate, Sodium arsenite, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA). Treatment with these arsenic compounds at the initiating stage induced significant numbers of transformed foci when cells were post-treated with 12-O-tetradecanoylphorbol-13-acetate (TPA). DiSodium Arsenate was active at the concentrations of 15-30 microM, Sodium arsenite 5-20 microM, and DMAA 1-2 mM. MMAA required 10 mM to induce cell transformation. The concentrations of these compounds (except DMAA) that induced transformation were highly growth-inhibitory (more than 50%). DMAA induced transformation foci at growth inhibition levels of 66 to 84%. In experiments on promoting activity, cells pretreated with a sub-threshold dose of 20-methylcholanthrene (MCA, 0.2 microg/ml) or Sodium arsenite (10 microM) were used. Transformation was enhanced by post-treatment with diSodium Arsenate (1-10 microM), Sodium arsenite (0.5-2 microM), and MMAA (200-1000 microM), but not with DMAA. Studies of gap junctional intercellular communication using the V79 cell metabolic cooperation assay showed that the arsenic compounds (except DMAA) exhibited inhibitory activity. Thus, most arsenicals were shown to have not only initiating activity, but also promoting activity. In addition, inorganic arsenicals, especially trivalent Sodium arsenite, were more active than organic ones and exhibited promoting activity at one-order of magnitude lower than initiating activity. These results suggest that from the viewpoint of human hazard, more attention should be paid to the tumor promoting activity of inorganic arsenic compounds.
Fujun Liu - One of the best experts on this subject based on the ideXlab platform.
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Thyrotoxicity of Sodium Arsenate, Sodium perchlorate, and their mixture in zebrafish Danio rerio.
Environmental science & technology, 2006Co-Authors: Fujun Liu, Jia-sheng Wang, Christopher W. TheodorakisAbstract:Both perchlorate and Arsenate are environmental contaminants. Perchlorate is a definitive thyroid disruptor, and arsenic may disrupt thyroid homeostasis via multiple pathways. To evaluate the effects of Sodium perchlorate and Sodium Arsenate on thyroid function and possible interactions between them, zebrafish (Danio rerio) were exposed to Sodium perchlorate (10 and 100 mg/L), Sodium Arsenate (1 and 10 mg/L), and the mixture Sodium perchlorate + Sodium Arsenate (10 + 1 and 100 + 10 mg/ L) for up to 90 days. At day 10, 30, 60, and 90, fish were sampled and analyzed forthyroid histopathological end points including follicular cell height, follicle size, colloid size, colloid depletion, hyperplasia, and angiogenesis. Effects on epithelial cell height (hypertrophy) were seen as early as 10 days after exposure. Perchlorate induced changes in all parameters staring at 30 days of exposure. Prolonged perchlorate exposure induced angiogenesis, a relatively new marker of thyroid disruption. Sodium Arsenate was less effective than Sodium perchlorate in causing thyroid histopathologies, but transient responses were seen for hypertrophy, hyperplasia, and colloid depletion (% colloid). This is the first report of Arsenate-induced effects on thyroid histopathology. However, because statistically significant effects were not consistently seen in all end points, evidence for Arsenate as a thyroid disruptor remains equivocal. In general, the sensitivity of the following histopathological indicators for indicating thyroid perturbations is, in descending order: follicular cell height > percent of colloid area/follicle area > colloid area/follicular cell height > hyperplasia > angiogenesis > colloid area >follicle area = fish growth.
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Short Communication JOINT TOXICITY OF Sodium Arsenate AND Sodium PERCHLORATE TO ZEBRAFISH DANIO RERIOLARVAE
2005Co-Authors: Fujun Liu, R Onald J. Kendall, Christopher W. T HeodorakisAbstract:Sodium perchlorate (purity, 99%; CAS 7790-89) was purchased from EM Science (Gibbstown, NJ, USA) and Sodium Arsenate (dibasic 7-hydrate; purity, 99%; CAS 7778-43-0) from J.T. Baker (Phillipsburg, NJ, USA). The static-renewal toxicity test followed standard procedures [14] using individual glass Petri dishes (60 3 15 mm) as replicates. Tests with Sodium Arsenate, Sodium perchlorate, and the mixtures consisted of a geometric series of five concentrations plus one control group, with 10 fish per replicate and five replicates per treatment. Exposure was conducted at a constant 288C and a photoperiod of 14:10-h light:dark. Two individual toxicity tests were first conducted to determine 96-h median lethal concentrations (LC50s) of individual chemicals (Arsenate and perchlorate). The design of the mixture-toxicity tests followed that described by Berenbaum [15] based on 96-h LC50s of the individual chemicals. Briefly, five concentrations of these two chemicals were used in a fixed ratio (Sodium Arsenate:Sodium perchlorate, 1:6.7) at approximately 12.5, 25, 50, 100, and 200% of their respective 96-h LC50s.
Xia Rong-xiang - One of the best experts on this subject based on the ideXlab platform.
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Correlation between level of arsenic methylation products and activity of methyltransferases in liver of rats treated with arsenite or Arsenate
Chinese Journal of Public Health, 2013Co-Authors: Xia Rong-xiangAbstract:Objective To analyze the association between the level of arsenite or Arsenate and its metabolites and the activity of methyltransferases,and to explore the relationship between arsenic's metabolism and toxicity.Methods Forty-two female Wistar rats were devided into 7 groups(normal control group;high,moderate,and low arsenite groups and high,moderate,and low Arsenate groups).After the animals were treated for three months,the liver were collected rapidly after the sacrifice and saved in a refrigerator.High efficiency liquid chromatography and hydride genesis atomic fluorescence spectroscopy(HPLC-HGAFS) were used to determine speciation and concentrations of Arsenate and arsenite and their metabolites in liver of the rats,and the activity of methyltransferases in the liver was determined.Meanwhile the correlation between the level of arsenic metabolites and the activity of methyltransferases was examined.Results The contents of iAs3+ for the rats in high,moderate,and low arsenite groups(255.9±58.6,61.1±10.2,and 62.6±17.3 ng/g) were significantly lower than those in Arsenate groups(P0.05 for all).The contents of dimethylarsinic acid(DMA) in the rats of high,modrate,and low arsenite groups(2 663.2±203.7,118.4±24.2,and 143.5±34.1 ng/g)were significantly lower than those in Arsenate groups(P0.05 for all).Meanwhile,the activity of methyltransferases in high,moderate,and low arsenite groups(4.81±0.25,2.32±0.41,and 1.82±0.25 μg/s · mg)were significantly lower than those in Arsenate groups(P0.05 for all).The activity of methyltransferase in liver correlated positively with the content of DMA and monomethylarsonic acid(MMA) by Spearman methods(P0.01),with the correlation coefficients of 0.594 and 0.497,respectively.Conclusion Both Arsenate Sodium and arsenite Sodium could increase(or decrease) the level of MMA and DMA by enhancing(or restraining) the activity of methyltransferase in liver,which would lead to different toxicity.
Toshiyuki Tsuchiya - One of the best experts on this subject based on the ideXlab platform.
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Inorganic arsenic compounds and methylated metabolites induce morphological transformation in two-stage BALB/c 3T3 cell assay and inhibit metabolic cooperation in V79 cell assay.
Toxicological Sciences, 2005Co-Authors: Toshiyuki Tsuchiya, Masanori Ando, Toshiko Tanaka-kagawa, Hideto Jinno, Kazunori Sakimoto, Hiroshi Tokunaga, Makoto UmedaAbstract:: We have performed two-stage transformation assay using BALB/c 3T3 cells to determine initiating and promoting activities of diSodium Arsenate, Sodium arsenite, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA). Treatment with these arsenic compounds at the initiating stage induced significant numbers of transformed foci when cells were post-treated with 12-O-tetradecanoylphorbol-13-acetate (TPA). DiSodium Arsenate was active at the concentrations of 15-30 microM, Sodium arsenite 5-20 microM, and DMAA 1-2 mM. MMAA required 10 mM to induce cell transformation. The concentrations of these compounds (except DMAA) that induced transformation were highly growth-inhibitory (more than 50%). DMAA induced transformation foci at growth inhibition levels of 66 to 84%. In experiments on promoting activity, cells pretreated with a sub-threshold dose of 20-methylcholanthrene (MCA, 0.2 microg/ml) or Sodium arsenite (10 microM) were used. Transformation was enhanced by post-treatment with diSodium Arsenate (1-10 microM), Sodium arsenite (0.5-2 microM), and MMAA (200-1000 microM), but not with DMAA. Studies of gap junctional intercellular communication using the V79 cell metabolic cooperation assay showed that the arsenic compounds (except DMAA) exhibited inhibitory activity. Thus, most arsenicals were shown to have not only initiating activity, but also promoting activity. In addition, inorganic arsenicals, especially trivalent Sodium arsenite, were more active than organic ones and exhibited promoting activity at one-order of magnitude lower than initiating activity. These results suggest that from the viewpoint of human hazard, more attention should be paid to the tumor promoting activity of inorganic arsenic compounds.
Christopher W. T Heodorakis - One of the best experts on this subject based on the ideXlab platform.
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Short Communication JOINT TOXICITY OF Sodium Arsenate AND Sodium PERCHLORATE TO ZEBRAFISH DANIO RERIOLARVAE
2005Co-Authors: Fujun Liu, R Onald J. Kendall, Christopher W. T HeodorakisAbstract:Sodium perchlorate (purity, 99%; CAS 7790-89) was purchased from EM Science (Gibbstown, NJ, USA) and Sodium Arsenate (dibasic 7-hydrate; purity, 99%; CAS 7778-43-0) from J.T. Baker (Phillipsburg, NJ, USA). The static-renewal toxicity test followed standard procedures [14] using individual glass Petri dishes (60 3 15 mm) as replicates. Tests with Sodium Arsenate, Sodium perchlorate, and the mixtures consisted of a geometric series of five concentrations plus one control group, with 10 fish per replicate and five replicates per treatment. Exposure was conducted at a constant 288C and a photoperiod of 14:10-h light:dark. Two individual toxicity tests were first conducted to determine 96-h median lethal concentrations (LC50s) of individual chemicals (Arsenate and perchlorate). The design of the mixture-toxicity tests followed that described by Berenbaum [15] based on 96-h LC50s of the individual chemicals. Briefly, five concentrations of these two chemicals were used in a fixed ratio (Sodium Arsenate:Sodium perchlorate, 1:6.7) at approximately 12.5, 25, 50, 100, and 200% of their respective 96-h LC50s.