Academic literature on the topic 'Arsenic Active oxygen'

Abstract Natural groundwater from the towns of Wabana and Freshwater and treated well water from the town of Wabana in Newfoundland and Labrador, Canada were tested separately and together in sand columns to study the removal of arsenic. The most ideal conditions for arsenic removal appeared to include an arsenic concentration of approximately 35 µg/L and lower, an Fe:As mass ratio in the order of 65 and lower, and aeration of the sand media. Active aeration by pumping air though the filter, passive aeration by scraping off top layers of sand and virtual aeration by diluting the strength of the water being treated, were employed and compared. For tests where groundwater from the towns of Wabana and Freshwater was combined, arsenic removal was optimized and other elements, in addition to iron, were also correlated with effluent arsenic. Further, for these same tests there was a gradual increase in effluent pH that could have been due to oxygen depletion or gradually more reducing conditions in the sand column. Where Ni, Mn and Zn were correlated with effluent arsenic it was concluded that the increase in pH increased heavy metal removal and arsenic release. In the test where the treated Wabana water made up a greater proportion of the mix than the Wabana groundwater, lithium was also correlated with arsenic.

Arsenic compounds can increase production of reactive oxygen species. Reactive oxygen species can induce double-strand breaks in DNA, which is a cause of chromosome aberrations (CAs). This study was conducted to determine the association between arsenic exposure and polymorphisms of genes involved in detoxification (glutathione S-transferase T1 [ GSTT1], glutathione S-transferase M1 [ GSTM1], glutathione S-transferase O2 [ GSTO2], catalase [ CAT], and NAD(P)H quinone oxidoreductase1 [ NQO1]) as well as nonhomologous end joining DNA repair genes ( XRCC4, XRCC5, and XRCC6) with induction of chromosomal aberrations. The participants consisted of 123 healthy males who were genotyped using polymerase chain reaction-based methods. Primary cultures of whole blood were treated with sodium arsenite (NaAsO2; iAs(III); at final concentration 1 µmol/L), mitomycin C (at final concentration 60 ηg/mL; as positive control), or untreated. For each culture, mitotic index (MI), chromatid breaks (CBs), CAs, and total percentage of aberrant cells were determined. The levels of CB and percentage of aberrant cells were significantly higher in the TT genotype of CAT (C-262T polymorphism) than the CC genotype. The CB value in samples with GSTM1 active genotype was significantly higher than the null genotype. The MI in samples with TT genotype of NQO1 (C609T polymorphism) was significantly higher than MI in samples having CC and CT genotypes. There was no association between MI, CB, CA, and percentage of aberrant cells and polymorphisms of XRCC4, XRCC5, and XRCC6.

Abstract Adult T-cell leukemia (ATL) is an aggressive lymphoproliferative disease of poor clinical prognosis associated with infection by the human T-cell leukemia virus type I (HTLV-I). The use of arsenic trioxide (As2O3) has been shown to effectively treat acute promyelocytic leukemia (APL) with greater than 80% of patients achieving complete remission. The combination of arsenic and interferon has also shown promising results in the treatment of ATL. The requirement for slow dosage increases of arsenic and the time required to achieve a pharmacologic active dose in patients is a major obstacle because median survival of patients with ATL is about 6 months. In this study we report a potent synergistic effect of the combination of arsenic trioxide and interferon α (As/IFN-α) with emodin and DHA on cell-cycle arrest and cell death of HTLV-I–infected cells. Importantly, we found that clinically achievable doses of DHA and emodin allowed for reduced arsenic concentrations by 100-fold while still remaining highly toxic to tumor cells. Our data provide a rationale for combined use of As/IFN-α with emodin and DHA in patients with ATL refractory to conventional therapy.

Aims: Arsenic has carcinogenic properties because of the formation of Reactive Oxygen Species (ROS). ROS damages different macromolecules, tissues and organs, and severely exhausts cellular antioxidants. Background: Cytosolic and mitochondrial contribution of ROS production by arsenic are not well reported. In regard to the issues of therapy against arsenic or any other toxicity, natural product has gained its popularity due to its less side-effects and non-invasive nature. Objectives: Here, as an ethnomedicine, the flesh-extract (BBE; 100mg/100g bw) of Bellamya bengalensis (an aquatic mollusk) was applied in arsenic intoxicated (0.6 ppm/100g bw/for 28 days alone or in combination with BBE) experimental rats. Our objective was to study the anti-oxidative and anti-apoptotic role of BBE in hepato-gastrointestinal tissue damage by arsenic. Methods: DNA fragmentation assay, catalase activity (gel-zymogram assay) suggests that BBE has a strong protective role against arsenic toxicity, which is decisively demonstrated in hepatic histoarchitecture study by HE (hematoxylin and eosin) staining and by intestinal PAS (Periodic Acid Schiff) staining. Results: Measurement of mitochondrial-membrane-potential by fluorescent microcopy clearly demonstrated less membrane damage and lower release of the redox-active inner-membrane product (cytochrome-C, ubiquinone, etc.) in BBE supplemented group compared to that of the only arsenic fed group. The present study clearly suggests that mitochondrial disintegrity is one of the major causes of ROS mediated tissue damage by arsenic. Conclusions: This study also offers an option for prevention/treatment against arsenic toxicity and its carcinogenicity by widely available low-cost, non-invasive Bellamya extract by protecting cytoskeleton, DNA and mitochondria in the cell.

Background/Aims: Exposure to arsenic in individuals has been found to be associated with various health-related problems including skin lesions, cancer, and cardiovascular and immunological disorders. (-)-Epigallocatechin-3-gallate (EGCG), the main and active polyphenolic catechin present in green tea, has shown potent antioxidant, anti-apoptotic and anti-inflammatory activity in vivo and in vitro. Thus, the present study was conducted to investigate the protective effects of EGCG against arsenic-induced inflammation and immunotoxicity in mice. Methods: Serum IL-1β, IL-6 and TNF-α were determined by ELISA, tissue catalase (CAT), malonyldialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), nitric oxide and caspase 3 by commercial kits, mitochondrial membrane potential with Rh 123, mitochondrial ROS with 2’,7’-dichlorofluorescin diacetate (DCFH-DA), apoptotic and necrotic cells and T-cell phenotyping with Flow cytometry analysis. Results: The results showed that arsenic treatment significantly increased oxidative stress levels (as indicated by catalase, malonyldialdehyde, superoxide dismutase, glutathione and reactive oxygen species), increased levels of inflammatory cytokines and promoted apoptosis. Arsenic exposure increased the relative frequency of the CD8+(Tc) cell subpopulation (from 2.8 to 18.9%) and decreased the frequency of CD4+(Th) cells (from 5.2 to 2.7%). Arsenic exposure also significantly decreased the frequency of T(CD3) (from 32.5% to 19.2%) and B(CD19) cells (from 55.1 to 32.5%). All of these effects induced by NaAsO2 were attenuated by EGCG. Conclusions: The present in vitro findings indicate that EGCG attenuates not only NaAsO2-induced immunosuppression but also inflammation and apoptosis.

Abstract Abstract 4759 Introduction Darinaparsin is an organic arsenic molecule constructed of dimethylated arsenic linked to glutathione (N-[S-(dimethylarsino)-N-L-gamma-glutamyl-L-cysteinyl]-glycine). It has a multifaceted mechanism of action, inducing G2/M cell cycle arrest and apoptosis mediated through disruption of mitochondrial functions, increased reactive oxygen species production, and modulation of signal transduction pathways. In addition, darinaparsin has anti-angiogenic activity. It has significant activity in a broad spectrum of hematologic and solid tumors in preclinical models, including human cell lines resistant to arsenic trioxide. It is active in heavily treated patients with refractory lymphoma when administered IV 300 mg/m2 for 5 days on a 28 day cycle, and is very well tolerated. Preclinically it is orally highly bioavailable. Oral administration may be of importance in potential utility in lymphoma in continuous metronomic dosing. Methods Two Phase I studies of oral darinaparsin are being conducted in patients diagnosed with relapsed or refractory advanced tumors. The first protocol is a Phase I, dose-escalation, oral administration study designed to determine the MTD of darinaparsin capsules. The dosing schedule is a regimen of 2 doses per week for 3 weeks followed by 1 week of rest, starting at 300 mg twice weekly. A second Phase I study, having a similar design and objective, evaluates several dosing regimens, including dosing capsules three times per week increasing dosing frequency to daily dosing for 3 weeks, with 1 week of rest. For each study 28 days constitutes one cycle. Standard methods for evaluation of toxicity, escalation and efficacy are being used. Results These two studies have thus far enrolled 19 and 17 patients, respectively. In total there are 24 male and 12 female patients. The median age is 59 years, with a range from 38 to 82 years. To date, MTD has not been reached in either study. The dose continues to be escalated and is currently at 900mg / day twice weekly in the 1st study, and 300 mg daily every day in the 2nd study. Bioavailability has been very high (>75%). All patients were heavily pretreated and refractory. Of 27 evaluable patients thus far in the two trials, 2 had a partial response and 15 had prolonged stable disease, including lymphoma (NHL), head and neck, colon, and pancreatic cancers. The duration of responses has been 3 – 8 + months. Safety and tolerability has been very good and comparable to that of IV darinaparsin. SAEs were atrial fibrillation and congestive heart failure, each occurring in one patient, and dyspnea, occurring in two patients. No QT prolongation has been observed. Dose escalation continues in both studies and updated results will be presented. Conclusion Darinaparsin is a novel organic arsenic molecule that has demonstrated clinical activity in refractory lymphoma when given IV. When given orally by capsule, the drug is well tolerated and demonstrates early signs of activity. Disclosures: Buck: ZIOPHARM Oncology: Employment. Wallner:ZIOPHARM Oncology: Employment. Lewis:ZIOPHARM Oncology: Employment, Membership on an entity's Board of Directors or advisory committees.

The content of vitamin C, carotenes, polyphenols, total carbohydrates and total soluble proteins was determined, alongside with the activity of the oxidative stress enzymes (superoxide-dismutase, catalase, peroxidase, isocitrat-dehydrogenase, ketoglutarat-dehydrogenase, succinat-dehydrogenase and malat-dehydrogenase) in Rosa canina L. samples collected from the heavy metals and arsenic polluted area around of Tarni�a closed mine, as well as from Sucevita area (as unpolluted site). The results showed an increase in the rose hip richness of nutrients and biological-active compounds, as well as the antioxidant activity of the samples from Tarnita area.We have explained our results taking into consideration the response of rosa plants to the oxidative stress produced by the accumulation of reactive oxygen species generated byexposure to pollutant factors from the contaminated area.

Mental health and active aging are two of the main concerns in the 21st century. To search for new neuroprotective compounds, extracts of Codium tomentosum Stackhouse and Fucus vesiculosus L. were obtained through multi-step (four step) subcritical water extraction using a temperature gradient. The safety assessment of the extracts was performed by screening pharmaceutical compounds and pesticides by UHPLC-MS/MS, and iodine and arsenic levels by ICP-MS. Although the extracts were free of pharmaceutical compounds and pesticides, the presence of arsenic and high iodine contents were found in the first two extraction steps. Thus, the health-benefits were only evaluated for the fractions obtained in steps 3 and 4 from the extraction process. These fractions were tested against five brain enzymes implicated in Alzheimer’s, Parkinson’s, and major depression etiology as well as against reactive oxygen and nitrogen species, having been observed a strong enzyme inhibition and radical scavenging activities for the step 4 fractions from both seaweed species. Regarding the variation of the chemical composition during the extraction, step 1 fractions were the richest in phenolic compounds. With the increase in temperature, Maillard reaction, caramelization and thermo-oxidation occurred, and the resulting products positively affected the antioxidant capacity and the neuroprotective effects.