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Sample records for chelates metal

  1. Chelation in Metal Intoxication

    OpenAIRE

    Flora, Swaran J.S.; Vidhu Pachauri

    2010-01-01

    Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3...

  2. Ferrocene base metal chelates

    International Nuclear Information System (INIS)

    Review of the works, devoted to different types of ferrocene metal chelates and to a possibility of ferrocene-containing ligand modification by means of complexing, is presented. Structure, properties and spectral characteristics of transitional metal, rare earth element, Cd2+, UO22+, Th4+ etc. complexes with ferrocene diketones, ferrocene acyl derivatives based on thiosemicarbazones and hydrazones and other heterometal ferrocene-containing metal chelates, are considered. 134 refs., 1 tab

  3. Chelation in metal intoxication

    DEFF Research Database (Denmark)

    Aaseth, Jan; Skaug, Marit Aralt; Cao, yang;

    2015-01-01

    The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due to the...... inconvenience of parenteral administration, their own toxicity and tendency to increase the neurotoxicity of several metals. The hydrophilic dithiol chelators DMSA (meso-2,3-dimercaptosuccinic acid) and DMPS (2,3-dimercapto-propanesulphonate) are less toxic and more efficient than BAL in the clinical treatment...... of heavy metal poisoning, and available as capsules for oral use. In copper overload, DMSA appears to be a potent antidote, although d-penicillamine is still widely used. In the chelation of iron, the thiols are inefficient, since iron has higher affinity for ligands with nitrogen and oxygen, but the...

  4. Bifunctional Chelates for Metal Nuclides

    OpenAIRE

    Brechbiel, Martin W.

    2007-01-01

    The use of “non-standard” metallic radionuclides continues to be an expanding field of investigation. Radiolabeling small molecules, peptides, proteins, and up to nano-particles are all areas of active investigation for both diagnostic and therapeutic applications. All require a common variable – the need for appropriate chelation chemistry for adequate sequestration of the metallic radionuclide that is equal to the intended application. A brief overview of the array of the chelation chemistr...

  5. Metal ions, Alzheimer's disease and chelation therapy.

    Science.gov (United States)

    Budimir, Ana

    2011-03-01

    In the last few years, various studies have been providing evidence that metal ions are critically involved in the pathogenesis of major neurological diseases (Alzheimer, Parkinson). Metal ion chelators have been suggested as potential therapies for diseases involving metal ion imbalance. Neurodegeneration is an excellent target for exploiting the metal chelator approach to therapeutics. In contrast to the direct chelation approach in metal ion overload disorders, in neurodegeneration the goal seems to be a better and subtle modulation of metal ion homeostasis, aimed at restoring ionic balance. Thus, moderate chelators able to coordinate deleterious metals without disturbing metal homeostasis are needed. To date, several chelating agents have been investigated for their potential to treat neurodegeneration, and a series of 8-hydroxyquinoline analogues showed the greatest potential for the treatment of neurodegenerative diseases. PMID:21406339

  6. Decorporation of metal ions by chelating agents

    International Nuclear Information System (INIS)

    Simple model designs to simulate the effect of therapeutical chelating agents on the behaviour of metals in mammal organisms with and without excretion have been derived and analytical solutions given for the corresponding differential equations. The possibilities of these models in the short-term description of plasma kinetics of various metals, the competition of the therapeutical ligands with proteins for the metal and of the metabolism of chelating agents were tested and the properties applying extreme conceivable parameters were analyzed. The simple models were successsively expanded in logical sequence, so that it was possible to qualitatively well describe over a long period of time, the metallic kinetics in plasma, organs and urine, the retention of the ligands and their effect on the metal excretion. Two suggestions were given to describe the so-called after-effect, an increased excretion of the metal at times when the ligand is almost completely excreted and their different behaviour after injecting the metal chelate is given. Calculations on the therapy with several ligand data as well as on dose fractionation are described resting on the ratios in the plutonium-239 chosen model parameters and the determining mechanisms analyzed. (orig./MG)

  7. Chemical treatment of chelated metal finishing wastes.

    Science.gov (United States)

    McFarland, Michael J; Glarborg, Christen; Ross, Mark A

    2012-12-01

    This study evaluated two chemical approaches for treatment of commingled cadmium-cyanide (Cd-CN) and zinc-nickel (Zn-Ni) wastewaters. The first approach, which involved application of sodium hypochlorite (NaOCl), focused on elimination of chelating substances. The second approach evaluated the use of sodium dimethyldithiocarbamate (DMDTC) to specifically target and precipitate regulated heavy metals. Results demonstrated that by maintaining a pH of 10.0 and an oxidation-reduction potential (ORP) value of +600 mV, NaOCl treatment was effective in eliminating all chelating substances. Cadmium, chromium, nickel, and zinc solution concentrations were reduced from 0.27, 4.44, 0.06, and 0.10 ppm to 0.16, 0.17, 0.03, and 0.06 ppm, respectively. Similarly, a 1% DMDTC solution reduced these same metal concentrations in commingled wastewater to 0.009, 1.142, 0.036, and 0.320 ppm. Increasing the DMDTC concentration to 2% improved the removal of all regulated heavy metals except zinc, the removal of which at high pH values is limited by its amphotericity. PMID:23342939

  8. Molecular mechanisms of in vivo metal chelation: implications for clinical treatment of metal intoxications.

    OpenAIRE

    Andersen, Ole; Aaseth, Jan

    2002-01-01

    Successful in vivo chelation treatment of metal intoxication requires that a significant fraction of the administered chelator in fact chelate the toxic metal. This depends on metal, chelator, and organism-related factors (e.g., ionic diameter, ring size and deformability, hardness/softness of electron donors and acceptors, route of administration, bioavailability, metabolism, organ and intra/extracellular compartmentalization, and excretion). In vivo chelation is not necessarily an equilibri...

  9. Metal regeneration of iron chelates in nitric oxide scrubbing

    Science.gov (United States)

    Chang, S.G.; Littlejohn, D.; Shi, Y.

    1997-08-19

    The present invention relates to a process of using metal particles to reduce NO to NH{sub 3}. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: (a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20 and 90 C to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution. 34 figs.

  10. Clawing Back: Broadening the Notion of Metal Chelators in Medicine

    OpenAIRE

    Franz, Katherine J.

    2013-01-01

    The traditional notion of chelation therapy is the administration of a chemical agent to remove metals from the body. But formation of a metal-chelate can have biological ramifications that are much broader than metal elimination. Exploring these other possibilities could lead to pharmacological interventions that alter the concentration, distribution, or reactivity of metals in targeted ways for therapeutic benefit. This review highlights recent examples that showcase four general strategies...

  11. Quantitative measurement of metal chelation by fourier transform infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Monika E. Miller

    2015-12-01

    Full Text Available Nutritionally important minerals are more readily absorbed by living systems when complexed with organic acids, resulting in higher consumer demand and premium prices for these products. These chelated metals are produced by reaction of metal oxides and acids in aqueous solution. However, unreacted dry blends are sometimes misrepresented as metal chelates, when in reality they are only simple mixtures of the reactants typically used to synthesize them. This practice has increased interest in developing analytical methods that are capable of measuring the extent of metal chelation for quality control and regulatory compliance. We describe a novel method to rapidly measure the percent chelation of citric and malic acids with calcium, magnesium, and zinc. Utilization of attenuated total reflectance (FTIR-ATR provides for the direct, rapid measurement of solid samples. The inclusion of an internal standard allows independent determination of either free or chelated acids from integrated areas in a single spectrum.

  12. Metal chelate conjugated monoclonal antibodies, wherein the metal is an α emitter

    International Nuclear Information System (INIS)

    Methods of manufacturing and purifying metal chelate conjugated monoclonal antibodies are described, wherein the chelated metal emits alpha radiation. The conjugates are suited for therapeutic uses being substantially free of nonchelated radiometal. (author)

  13. Chelation therapy for metal intoxication: comments from a thermodynamic viewpoint.

    Science.gov (United States)

    Nurchi, Valeria Marina; Alonso, Miriam Crespo; Toso, Leonardo; Lachowicz, Joanna Izabela; Crisponi, Guido

    2013-10-01

    Chelation therapy plays a prominent role in the clinical treatment of metal intoxication. In this paper the principal causes of metal toxicity are exposed, and the chemical and biomedical requisites of a chelating agent are sketched. The chelating agents currently in use for scavenging toxic metal ions from humans belong to few categories: those characterized by coordinating mercapto groups, by oxygen groups, poliaminocarboxylic acids, and dithiocarbamates. Considering that the complex formation equilibria have been studied for less than 50% of chelators in use, some reflections on the utility of stability constants are presented, together with an evaluation of ligands under the stability profile. The competition between endogenous and toxic target metal ions for the same chelating agent is furthermore examined. A thorough examination of stability constant databases has allowed to select, for each toxic metal, the ligands distinguished by the best pMe values. Even though this selection does not consider the biomedical requisites of a chelating agent, it gives a clear picture both of the pMe values that can be attained, and of the most appropriate chelators for each metal ion. PMID:23895193

  14. Chelation: Harnessing and Enhancing Heavy Metal Detoxification—A Review

    OpenAIRE

    Sears, Margaret E.

    2013-01-01

    Toxic metals such as arsenic, cadmium, lead, and mercury are ubiquitous, have no beneficial role in human homeostasis, and contribute to noncommunicable chronic diseases. While novel drug targets for chronic disease are eagerly sought, potentially helpful agents that aid in detoxification of toxic elements, chelators, have largely been restricted to overt acute poisoning. Chelation, that is multiple coordination bonds between organic molecules and metals, is very common in the body and at the...

  15. Antioxidant, Free Radical Scavenging and Metal Chelating Characteristics of Propolis

    OpenAIRE

    Hikmet Geckil; Burhan Ates; Gokhan Durmaz; Selim Erdogan; Ismet Yilmaz

    2005-01-01

    This study was undertaken to determine the reducing characteristics, metal chelating capability, anti-lipid peroxidative and antiradical properties of propolis compared to two widely used artificial antioxidants, Butylated Hydroxyanisole (BHA) and Butylated Hydroxytoluene (BHT). The water and ethanol extracts of propolis showed significantly a different degree of metal chelating, radical scavenging activity and reducing power. In general, ethanol extracts of propolis showed higher activity re...

  16. Hydrogen peroxide- metals- chelating agents; interactions and analytical techniques

    OpenAIRE

    Rämö, J.

    2003-01-01

    Abstract Information about interactions among metals, hydrogen peroxide and chelating agents is needed to develop environmental technology and the operating efficiency of modern elemental chlorine free and total chlorine free bleaching processes. The work presented here focused on the properties of metal chelates and corrosion of titanium in an alkaline hydrogen peroxide solution. A comparative study between three rapid analysis methods, ICP-AES, XRF and ISE, was performed in pulp matrix a...

  17. Heavy metal displacement in chelate-irrigated soil during phytoremediation

    Science.gov (United States)

    Madrid, F.; Liphadzi, M. S.; Kirkham, M. B.

    2003-03-01

    Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavy metals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavy metals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavy metals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavy metals for maximum uptake during chelate-assisted phytoremediation.

  18. Chelation And Extraction Of Metals For GC-MS Analysis

    Science.gov (United States)

    Sinha, Mahadeva P.

    1995-01-01

    Chelation followed by supercritical-fluid extraction enables mass-spectrometric analysis. When fully developed, method implemented in field-portable apparatus for detection and quantification of metals in various matrices without need for elaborate preparation of samples. Used to analyze soil samples for toxic metals.

  19. Chelating impact assessment of biological ad chemical chelates on metal extraction from contaminated soils

    International Nuclear Information System (INIS)

    Soil contamination is the result of uncontrolled waste dumping and poor practices by humans. Of all the pollutants heavy metals are of particular concern due to their atmospheric deposition, leaching capacity and non-biodegradability. Heavy metal containing effluent is discharged into the agricultural fields and water bodies. This results in the accumulation of heavy metals in soil and the crops grown on that soil. Studies have revealed detrimental impacts on soil fertility and the poor health of animals and humans. Phytoextraction is widely researched for remediation of heavy metal contaminated soil. To enhance the effect of phytoextraction heavy metals have to be available to the plants in soluble form. In this study the potential of different chelating agents was assessed in solubilizing the heavy metals making easy for plants to uptake them. For this purpose efficient chemical and biological chelating agent had to be identified. Along with that an optimum dose and application time for chemical chelating agent was determined. Ethylenediamine tetraacetic acid (EDTA), Diethylene triamine pentaacetic acid (DTPA), Nitriloacetic acid (NTA) were applied to the soil, containing Pb, Cr, Cu and Cd, at different concentrations and application time. Aspergillus niger and Aspergillus flavus were incubated in soil for different time periods. In correspondence with findings of the study, Pb and Cr were best solubilized by 5mM EDTA. For Cd and Cu 5mM DTPA carried out efficient chelation. NTA showed relatively inadequate solubilisation, although for Cr it performed equal to EDTA. A. niger and A. flavus instead of solubilizing adsorbed the metals in their biomass. Adsorption was mainly carried out by A. niger. (author)

  20. Antioxidant, Free Radical Scavenging and Metal Chelating Characteristics of Propolis

    Directory of Open Access Journals (Sweden)

    Hikmet Geckil

    2005-01-01

    Full Text Available This study was undertaken to determine the reducing characteristics, metal chelating capability, anti-lipid peroxidative and antiradical properties of propolis compared to two widely used artificial antioxidants, Butylated Hydroxyanisole (BHA and Butylated Hydroxytoluene (BHT. The water and ethanol extracts of propolis showed significantly a different degree of metal chelating, radical scavenging activity and reducing power. In general, ethanol extracts of propolis showed higher activity regarding these parameters. Synthetic antioxidants showed better activities than both propolis extracts for antioxidant properties, utilizing a -carotene bleaching method. At higher concentrations, the reducing power of ethanol extract of propolis was similar to that of artificial antioxidants. The metal chelating activity of both water and ethanol extracts of propolis was comparable to that of EDTA and significantly higher than both BHA and BHT.

  1. Laccase Immobilization by Chelated Metal Ion Coordination Chemistry

    Directory of Open Access Journals (Sweden)

    Qingqing Wang

    2014-09-01

    Full Text Available In this work, amidoxime polyacrylonitrile (AOPAN nanofibrous membrane was prepared by a reaction between PAN nanofibers and hydroxylamine hydrochloride. The AOPAN nanofibrous membranes were used for four metal ions (Fe3+, Cu2+, Ni2+, Cd2+ chelation under different conditions. Further, the competition of different metal ions coordinating with AOPAN nanofibrous membrane was also studied. The AOPAN chelated with individual metal ion (Fe3+, Cu2+, Ni2+, Cd2+ and also the four mixed metal ions were further used for laccase (Lac immobilization. Compared with free laccase, the immobilized laccase showed better resistance to pH and temperature changes as well as improved storage stability. Among the four individual metal ion chelated membranes, the stability of the immobilized enzymes generally followed the order as Fe–AOPAN–Lac > Cu–AOPAN–Lac > Ni–AOPAN–Lac > Cd–AOPAN–Lac. In addition, the immobilized enzyme on the carrier of AOPAN chelated with four mixed metal ions showed the best properties.

  2. Extraction of metals using supercritical fluid and chelate forming ligand

    International Nuclear Information System (INIS)

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated β-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated β-diketone and a trialkyl phosphate, or a fluorinated β-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated β-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process. 7 figs

  3. Extraction rate of metal ion by chelating agent

    International Nuclear Information System (INIS)

    In order to clarify the extraction mechanism of metal ion by a chelating agent, it is problematic to infer the mechanism on the basis of the dependence of the extraction rate upon the concentration of the agent. For this purpose, the information as follows is essential: (1) computation of physical chemistry constants of the chelating agent, (2) the reaction rate for chelate formation with the metal ion in the water phase and the mechanism, and (3) the measurement of the extraction rate by use of the apparatus for which the oil/water interface area and the interface-material transfer coefficient are known. It is then necessary to establish the design guidance of reaction field and separation field via the accumulation of the experimental results. (Mori, K.)

  4. Chelate-Assisted Heavy Metal Movement Through the Root Zone

    Science.gov (United States)

    Kirkham, M.; Madrid, F.; Liphadzi, M. S.

    2001-12-01

    Chelating agents are added to soil as a means to mobilize heavy metals for plant uptake during phytoremediation. Yet almost no studies follow the displacement of heavy metals through the vadose zone following solubilization with chelating agents. The objective of this work was to determine the movement of heavy metals through the soil profile and their absorption by barley (Hordeum vulgare L.) in a soil amended with biosolids and in the presence of a chelating agent (EDTA). Twelve columns 75 cm in height and 17 in diameter were packed with a Haynie very fine sandy loam (coarse-silty, mixed, calcareous, mesic Mollic Udifluvents) and watered with liquid biosolids applied at the surface at a rate of 120 kg N/ha. Three weeks after plants germinated, soil was irrigated with a solution of the disodium salt of EDTA added at a rate of 0.5 g/kg soil. Four treatments were imposed: columns with no plants and no EDTA; columns with no plants plus EDTA; columns with plants and no EDTA; and columns with plants and EDTA. Columns were watered intensively for 35 days until two pore volumes of water had been added, and the leachates were collected daily. With or without plants, columns with EDTA had lower total concentrations of Cu, Zn, Cd, Ni, and Pb in the surface 20 cm than columns without EDTA. Concentrations of the heavy metals in this layer were not afffected by the presence of roots. Iron in leachate was followed as an indicator metal for movement to groundwater. No iron appeared in the leachate without EDTA, either in the columns with plants or without plants. The peak concentration of iron in the leachate occurred three days earlier in the columns without plants and EDTA compared to the columns with plants and EDTA. The results indicated the importance of vegetation on retarding heavy metal leaching to groundwater during chelate-facilitated phytoremediation.

  5. New Regeneration process of heavy metals loaded chelating resin

    OpenAIRE

    Menoud, P.; Cavin, L.; Renken, A.

    2000-01-01

    An alternative to the classical acid-base regeneration of chelating resins loaded with heavy metals is investigated. The new process consists in recovering the heavy metals with recyclable soluble complexing agents. The semiclosed reactor includes a fixed bed and a stirred tank. A three-parameter model, which implies a double equilibrium in series, is introduced. When less than 10 % of the metal is still fixed on the resin at the end of the desorption, a simplified form of the model with two ...

  6. Metal chelates of 2-acetylbenzimidazole thiosemicarbazones

    International Nuclear Information System (INIS)

    Earlier unknown complexes of ML' and ML2 compositions were prepared on the basis of thiosemicarbazones of 2-acetylbenzimidazole (L'H2) and 2-acetyl-1-methylbenzimidazole (LH) and metal (M=Cu2+, VO2+, Co2+, Ni2+) acetates in ethanol medium. Data of IR and ESR spectra and magnetochemical measurements, as well as correlation of experimental and calculated values of the polar magnetic susceptibility in 80-300K range enabled to assign polymeric structure to complexes of ML' composition and monomeric structure - to complexes of ML2 composition

  7. Investigation of the chelation effect on the voltammetric behaviour of selected metals

    International Nuclear Information System (INIS)

    Iron, cadmium, aluminum and chromium could be easily determined by voltammetric methods. The chelation behaviour of chelating agents like hydroxyquinoline, NaDEDC, cupferron etc. have been investigated on the voltammetric behavior of these metals. The results were compared with the spectro fluorimetric investigation of these metal chelates and a relation between voltammetric and fluorimetric behaviour have been established. (author)

  8. High precision isotopic ratio analysis of volatile metal chelates

    International Nuclear Information System (INIS)

    High precision isotope ratio measurements have been made for a series of volatile alkaline earth and transition metal chelates using conventional GC/MS instrumentation. Electron ionization was used for alkaline earth chelates, whereas isobutane chemical ionization was used for transition metal studies. Natural isotopic abundances were determined for a series of Mg, Ca, Cr, Fe, Ni, Cu, Cd, and Zn chelates. Absolute accuracy ranged between 0.01 and 1.19 at. %. Absolute precision ranged between +-0.01-0.27 at. % (RSD +- 0.07-10.26%) for elements that contained as many as eight natural isotopes. Calibration curves were prepared using natural abundance metals and their enriched 50Cr, 60Ni, and 65Cu isotopes covering the range 0.1-1010.7 at. % excess. A separate multiple isotope calibration curve was similarly prepared using enriched 60Ni (0.02-2.15 at. % excess) and 62Ni (0.23-18.5 at. % excess). The samples were analyzed by GC/CI/MS. Human plasma, containing enriched 26Mg and 44Ca, was analyzed by EI/MS. 1 figure, 5 tables

  9. Capillary gas chromatography of metal chelates of diethyl dithiocarbamates

    Energy Technology Data Exchange (ETDEWEB)

    Arain, M.A.; Bhanger, M.I. [Center of Excellence in Analytical Chemistry (Pakistan); Khuhawar, M.Y. [M.A. Kazi Inst. of Chemistry, Univ. of Sindh, Jamshoro (Pakistan)

    2002-03-01

    Capillary GC of metal chelates of diethyl dithiocarbamate (DDTC) was examined on a methylsilicone DB-1 column, (25 meter, 0.2 mm. i.d) with a film thickness of 0.25 {mu}m. Elution was carried out at the initial column temperature of 180 C and programmed at 5 C min{sup -1} to 260 C. Detection was by FID or ECD. Symmetrical peaks with bse line separation were obtained with the metal chelates of copper(II), nickel(II), cobalt(III), manganese(II) and chromium(III). The ECD gave better sensitivity than the FID with a linear calibration range of 5 - 50 {mu}g mL{sup -1} and detection limits 2.0 - 6.0 {mu}g mL{sup -1}, corresponding to 111 - 333 pg of metal ion reaching the detector. The method was applied to the determination of metal ions in water and pharmaceutical preparations with a coefficient of variation (CV) within 4.0%. When compared with a standard flame AAS method the results revealed no significant difference. (orig.)

  10. Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO2. 1998 annual progress report

    International Nuclear Information System (INIS)

    'This report summarizes work after 1 year and 8 months (9/15/96-5/14/98) of a 3 year project. Thus far, progress has been made in: (1) the measurement of the solubility of metal chelates in SC CO2 with and without added cosolvents, (2) the spectroscopic determination of preferential solvation of metal chelates by cosolvents in SC CO2 solutions, and (3) the development of a totally reliable computational technique for phase equilibrium computations. An important factor in the removal of metals from solid matrices with CO2/chelate mixtures is the equilibrium solubility of the metal chelate complex in the CO2.'

  11. Modelling chelate-Induced phytoextraction: functional models predicting bioavailability of metals in soil, metal uptake and shoot biomass

    Directory of Open Access Journals (Sweden)

    Pasqualina Sacco

    Full Text Available Chelate-induced phytoextraction of heavy metals from contaminated soils requires special care to determine, a priori, the best method of chelate application, in terms of both dose and timing. In fact, the chelate dose must assure the bioavailability of the metal to the plant without increasing leaching risk and giving toxic effects. Three mathematical models are here proposed for usefully interpreting the processes taking place: a increased soil bioavailability of metals by chelants; b metal uptake by plants; c variation in plant biomass. The models are implemented and validated using data from pot and lysimeter trials. Both the chelate dose and the time elapsed since its application affected metal bioavailability and plant response. Contrariwise, the distribution strategy (single vs. split application seems to produce significant differences both in plant growth and metal uptake, but not in soil metal bioavailability. The proposed models may help to understand and predict the chelate dose – effect relationship with less experimental work.

  12. The Role of Chelation in the Treatment of Other Metal Poisonings

    OpenAIRE

    Smith, Silas W.

    2013-01-01

    These proceedings will review the role of chelation in five metals—aluminum, cadmium, chromium, cobalt, and uranium—in order to illustrate various chelation concepts. The process of “chelation” can often be oversimplified, leading to incorrect assumptions and risking patient harm. For chelation to be effective, two critical assumptions must be fulfilled: the presumed “metal toxicity” must correlate with a given body or a particular compartment burden, and reducing this compartmental or the bo...

  13. Chelating capture and magnetic removal of non-magnetic heavy metal substances from soil

    OpenAIRE

    Liren Fan; Jiqing Song; Wenbo Bai; Shengping Wang; Ming Zeng; Xiaoming Li; Yang Zhou; Haifeng Li; Haiwei Lu

    2016-01-01

    A soil remediation method based on magnetic beneficiation is reported. A new magnetic solid chelator powder, FS@IDA (core-shell Fe3O4@SiO2 nanoparticles coated with iminodiacetic acid chelators), was used as a reactive magnetic carrier to selectively capture non-magnetic heavy metals in soil by chelation and removal by magnetic separation. FS@IDA was prepared via inorganic-organic and organic synthesis reactions that generated chelating groups on the surface of magnetic, multi-core, core-shel...

  14. The fabrication and study of metal chelating stationary phases for the high performance separation of metal ions

    International Nuclear Information System (INIS)

    The preparation and characterisation of chelating sorbents suitable for the high efficiency separation of trace metals in complex samples, using a single column and isocratic elution, is described. Hydrophobic, neutral polystyrene divinylbenzene resins were either impregnated with chelating dyes or dynamically modified with heterocyclic organic acids, using physical adsorption and chemisorption processes respectively. A hydrophilic silica substrate was covalently bonded with a chelating aminomethylphosphonic acid group, to assess the chelating potential of this molecule. These substrates were characterised in terms of metal retention capability (selectivity coefficients and capacity factors), separation performance, column efficiency and suitability for analytical applications. Chelating molecules with different ligand groups were found to have unique selectivity patterns dependant upon the conditional stability constants of the chelate. Other factors, including mobile phase constituents - complexing agents, ionic strength and pH, column length and column capacity were additionally investigated to examine their effect upon the separation profiles achieved. The promising metal separation abilities illustrated by a number of these chelating columns were exploited for the determination of trace toxic metals in complex sample matrices using High Performance Chelation Ion Chromatography (HPCIC). This included the determination of beryllium in a certified stream sediment, uranium in seawater and a certified stream sediment, and cadmium, lead and copper in a certified rice flour. The results for each analysis fell within the certified limits, and reproducibility was good. The optimisation of post column detection systems using chromogenic ligands additionally gave good detection limits for the metals in each separation system. (author)

  15. Method for separating metal chelates from other materials based on solubilities in supercritical fluids

    Energy Technology Data Exchange (ETDEWEB)

    Wai, Chien M. (Moscow, ID); Smart, Neil G. (Workington, GB); Phelps, Cindy (Moscow, ID)

    2001-01-01

    A method for separating a desired metal or metalloi from impurities using a supercritical extraction process based on solubility differences between the components, as well as the ability to vary the solvent power of the supercritical fluid, is described. The use of adduct-forming agents, such as phosphorous-containing ligands, to separate metal or metalloid chelates in such processes is further disclosed. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of .beta.-diketones; phosphine oxides, such as trialkylphosphine oxides, triarylphosphine oxides and alkylarylphosphine oxides; phosphinic acids; carboxylic acids; phosphates, such as trialkylphosphates, triarylphosphates and alkylarylphosphates; crown ethers; dithiocarbamates; phosphine sulfides; phosphorothioic acids; thiophosphinic acids; halogenated analogs of these chelating agents; and mixtures of these chelating agents. In especially preferred embodiments, at least one of the chelating agents is fluorinated.

  16. Targeted Catalytic Inactivation of Angiotensin Converting Enzyme by Lisinopril-Coupled Transition Metal Chelates

    OpenAIRE

    Joyner, Jeff C.; Hocharoen, Lalintip; Cowan, J. A.

    2012-01-01

    A series of compounds that target reactive transition metal chelates to somatic Angiotensin Converting Enzyme (sACE-1) have been synthesized. Half maximal inhibitory concentrations (IC50) and rate constants for both inactivation and cleavage of full length sACE-1 have been determined and evaluated in terms of metal-chelate size, charge, reduction potential, coordination unsaturation, and coreactant selectivity. Ethylenediamine-tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), 1,4,7,10-tet...

  17. Targeted Cleavage of HIV RRE RNA by Rev-Coupled Transition Metal Chelates

    OpenAIRE

    Joyner, Jeff C.; Cowan, J. A.

    2011-01-01

    A series of compounds that target reactive metal-chelates to the HIV-1 Rev Response Element (RRE) mRNA have been synthesized. Dissociation constants and chemical reactivity toward HIV RRE RNA have been determined and evaluated in terms of reduction potential, coordination unsaturation, and overall charge associated with the metal-chelate-rev complex. Ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), and 1,4,7,10-tetraazacyclo-dodec...

  18. Metal Extraction From Soil Samples By chelation in a Microwave System

    OpenAIRE

    Chatreewongsin, Urai

    2000-01-01

    This work involves the combination of chelation and microwave extraction as a technique for extracting adsorbed metals in soil. It has been termed in this work, Chelate Assisted Microwave Extraction (CAME). Unlike other extraction methods, CAME is able to differentiate between anthropological and geological trace metals. The method has been applied to major sample matrices included three types of soils (Bertie Sandy Loam, Davidson Silty Clay, and Davidson Clayey Loam) as well as se...

  19. Chelating capture and magnetic removal of non-magnetic heavy metal substances from soil

    Science.gov (United States)

    Fan, Liren; Song, Jiqing; Bai, Wenbo; Wang, Shengping; Zeng, Ming; Li, Xiaoming; Zhou, Yang; Li, Haifeng; Lu, Haiwei

    2016-02-01

    A soil remediation method based on magnetic beneficiation is reported. A new magnetic solid chelator powder, FS@IDA (core-shell Fe3O4@SiO2 nanoparticles coated with iminodiacetic acid chelators), was used as a reactive magnetic carrier to selectively capture non-magnetic heavy metals in soil by chelation and removal by magnetic separation. FS@IDA was prepared via inorganic-organic and organic synthesis reactions that generated chelating groups on the surface of magnetic, multi-core, core-shell Fe3O4@SiO2 (FS) nanoparticles. These reactions used a silane coupling agent and sodium chloroacetate. The results show that FS@IDA could chelate the heavy metal component of Cd, Zn, Pb, Cu and Ni carbonates, lead sulfate and lead chloride in water-insoluble salt systems. The resulting FS@IDA-Cd and FS@IDA-Pb chelates could be magnetically separated, resulting in removal rates of approximately 84.9% and 72.2% for Cd and Pb, respectively. FS@IDA could not remove the residual heavy metals and those bound to organic matter in the soil. FS@IDA did not significantly alter the chemical composition of the soil, and it allowed for fast chelating capture, simple magnetic separation and facilitated heavy metal elution. FS@IDA could also be easily prepared and reprocessed.

  20. Targeted cleavage of HIV RRE RNA by Rev-coupled transition metal chelates.

    Science.gov (United States)

    Joyner, Jeff C; Cowan, J A

    2011-06-29

    A series of compounds that target reactive metal chelates to the HIV-1 Rev response element (RRE) mRNA have been synthesized. Dissociation constants and chemical reactivity toward HIV RRE RNA have been determined and evaluated in terms of reduction potential, coordination unsaturation, and overall charge associated with the metal-chelate-Rev complex. Ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) were linked to a lysine side chain of a Rev-derived peptide by either EDC/NHS or isothiocyanate coupling. The resulting chelate-Rev (EDTA-Rev, DTPA-Rev, NTA-Rev, and DOTA-Rev) conjugates were used to form coordination complexes with Fe(2+), Co(2+), Ni(2+), and Cu(2+) such that the arginine-rich Rev peptide could mediate localization of the metal chelates to the Rev peptide's high-affinity mRNA binding partner, RRE stem loop IIB. Metal complexes of the extended peptides GGH-Rev and KGHK-Rev, which also contain N-terminal peptidic chelators (ATCUN motifs), were studied for comparison. A fluorescence titration assay revealed high-affinity RRE RNA binding by all 22 metal-chelate-Rev species, with K(D) values ranging from ~0.2 to 16 nM, indicating little to no loss of RNA affinity due to the coupling of the metal chelates to the Rev peptide. Dissociation constants for binding at a previously unobserved low-affinity site are also reported. Rates of RNA modification by each metal-chelate-Rev species were determined and varied from ~0.28 to 4.9 nM/min but were optimal for Cu(2+)-NTA-Rev. Metal-chelate reduction potentials were determined and varied from -228 to +1111 mV vs NHE under similar solution conditions, allowing direct comparison of reactivity with redox thermodynamics. Optimal activity was observed when the reduction potential for the metal center was poised between those of the two principal co-reagents for metal-promoted formation of

  1. Thiophene-based ligands as potential new metal ion chelation units in nuclear medicine

    International Nuclear Information System (INIS)

    An effort to explore new metal chelation units for radiopharmaceutical metal ion chelation applications has led us to the 2,5-dialkylamide-3,4-dihydroxythiophene type chelators. The ligand synthesis allows for facile asymmetric substitution that produces the amide-ester. Also, the monobenzyl derivative was obtained and structurally characterized in the P-1 space group with unit cell dimensions a = 10.111(3) A, b 11.761(3) A, c = 12.014(3) A , α = 72.987(5) .deg., β = 88.576(5) .deg., γ = 71.441(5) .deg., V = 1291.3(6) A3, Z = 2. The asymmetric hydrogen bonding pattern suggests the alternative salicylate-type metal chelation is accessible

  2. Heavy metal induced oxidative stress & its possible reversal by chelation therapy.

    Science.gov (United States)

    Flora, S J S; Mittal, Megha; Mehta, Ashish

    2008-10-01

    Exposure to heavy metals is a common phenomenon due to their environmental pervasiveness. Metal intoxication particularly neurotoxicity, genotoxicity, or carcinogenicity is widely known. This review summarizes our current understanding about the mechanism by which metalloids or heavy metals (particularly arsenic, lead, cadmium and mercury) induce their toxic effects. The unifying factor in determining toxicity and carcinogenicity for all these metals is the generation of reactive oxygen and nitrogen species. The toxic manifestations of these metals are caused primarily due to imbalance between pro-oxidant and antioxidant homeostasis which is termed as oxidative stress. Besides these metals have high affinity for thiol groups containing enzymes and proteins, which are responsible for normal cellular defense mechanism. Long term exposure to these metals could lead to apoptosis. Signaling components affected by metals include growth factor receptors, G-proteins, MAP kinases and transcription factors. Chelation therapy with chelating agents like calcium disodium ethylenediamine tetra acetic acid (CaNa(2)EDTA), British Anti Lewisite (BAL), sodium 2,3-dimercaptopropane 1-sulfonate (DMPS), meso 2,3-dimercaptosuccinic acid (DMSA) etc., is considered to be the best known treatment against metal poisoning. Despite many years of research we are still far away from effective treatment against toxicity caused due to exposure to heavy metals/metalloids. The treatment with these chelating agents is compromised with number of serious side-effects. Studies show that supplementation of antioxidants along-with a chelating agent prove to be a better treatment regimen than monotherapy with chelating agents. This review attempts a comprehensive account of recent developments in the research on heavy metal poisoning particularly the role of oxidative stress/free radicals in the toxic manifestation, an update about the recent strategies for the treatment with chelating agents and a

  3. [Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents

    International Nuclear Information System (INIS)

    Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III)

  4. [Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

  5. (Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents)

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

  6. Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO2

    International Nuclear Information System (INIS)

    The overall objectives of this project were to gain a fundamental understanding of the solubility and phase behavior of metal chelates in supercritical CO2. Extraction with CO2 is an excellent way to remove organic compounds from soils, sludges and aqueous solutions, and recent research has demonstrated that, together with chelating agents, it is a viable way to remove metals, as well. In this project the authors sought to gain fundamental knowledge that is vital to computing phase behavior, and modeling and designing processes using CO2 to separate organics and metal compounds from DOE mixed wastes. The overall program was a comprehensive one to measure, model and compute the solubility of metal chelate complexes in supercritical CO2 and CO2/cosolvent mixtures. Through a combination of phase behavior measurements, spectroscopy and the development of a new computational technique, the authors have achieved a completely reliable way to model metal chelate solubility in supercritical CO2 and CO2/co-contaminant mixtures. Thus, they can now design and optimize processes to extract metals from solid matrices using supercritical CO2, as an alternative to hazardous organic solvents that create their own environmental problems, even while helping in metals decontamination

  7. Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    J. F. Brennecke; M. A. Stadtherr

    1999-12-10

    The overall objectives of this project were to gain a fundamental understanding of the solubility and phase behavior of metal chelates in supercritical CO{sub 2}. Extraction with CO{sub 2} is an excellent way to remove organic compounds from soils, sludges and aqueous solutions, and recent research has demonstrated that, together with chelating agents, it is a viable way to remove metals, as well. In this project the authors sought to gain fundamental knowledge that is vital to computing phase behavior, and modeling and designing processes using CO{sub 2} to separate organics and metal compounds from DOE mixed wastes. The overall program was a comprehensive one to measure, model and compute the solubility of metal chelate complexes in supercritical CO{sub 2} and CO{sub 2}/cosolvent mixtures. Through a combination of phase behavior measurements, spectroscopy and the development of a new computational technique, the authors have achieved a completely reliable way to model metal chelate solubility in supercritical CO{sub 2} and CO{sub 2}/co-contaminant mixtures. Thus, they can now design and optimize processes to extract metals from solid matrices using supercritical CO{sub 2}, as an alternative to hazardous organic solvents that create their own environmental problems, even while helping in metals decontamination.

  8. Wood impregnated with metal chelates dissolved in organic media tested for termite resistance

    Directory of Open Access Journals (Sweden)

    Lara Maistrello

    2011-08-01

    Full Text Available Wood manufactured products are subjected to biological decay due to fungi and insects. The use of copper chelates as biocides was proposed, due to their high stability which minimizes copper leaching into the environment. Considering the remarkable effectiveness showed by copper chelates on brown rot fungi, zinc and copper salicylate complexes were prepared in order to have metal chelates soluble in organic media available. The present study aimed at evaluating these metal chelates complexes as preservative agents for wood treatment against termites. Trials were performed on Reticulitermes lucifugus (Rossi and Kalotermes flavicollis (Fabricius. Results showed that in both termite species wood consumption was significantly lower on Cu-chelates treated samples compared to untreated wood, whereas the wood slices impregnated with Zn-chelates and the organic media alone gave an intermediate response. Interestingly, in one case solvent-impregnated wood was significantly more attractive than untreated wood for both species and further investigations are being carried out to clarify this behaviour.

  9. Study of chelating agent as a surface modifier for retarding corrosion attack on ferrous metal

    International Nuclear Information System (INIS)

    A different concentration of chelating agents in electrolyte of 3.5 % NaCl was applied to bare ferrous metal and tested for their effectiveness as a corrosion retardant. The performance of the samples was measured using corrosion measurement system. The results indicated that the contribution of chelating agent was expediting the reduction of the passive film. The anodic behavior was clearly found to be influenced by the concentration of the chelating agent. It was also found that some of the corrosion was apparently converted to protective layer over a period of time. Excessive moisture caused breakdown of film by removing the unreacted chelating agent and causing regrowth of the existing rust. (author)

  10. Chelation of Schiff bases with rare earth metal ions - thermodynamic study

    International Nuclear Information System (INIS)

    Chelating tendencies of 5-chloro-orthohydroxy acetophenone-p-chloro phenyl anil and 5-chloro-orthohydroxy acetophenone-p-bromo phenyl anil towards the f-block metal ions have been investigated potentiometrically at various temperatures in 60:40 ethanol-water medium and 0.1M (NaClO4) ionic strength. Formation of 1:1 and 1:2 chelates was detected. Thermodynamic parameters for metal-ligand stability constants have been obtained by the temperature coefficie nt method. (author). 7 refs

  11. Synthesis, characterization and biological studies of 1,7- dinaphthyl heptanoids and their metal chelates

    OpenAIRE

    S. Sindhu; Seena Thomachan; V D John

    2015-01-01

    The present investigation includes the synthesis, characterization, antitumour and antimicrobial activities of three new curcuminoid analogues and their metal chelates. Curcuminoid analogues and their metal chelates have great ability to act as antitumour and antimicrobial agents which motivated us and lead to this present work. The new curcuminoid analogues namely 1,7-di(1-naphthyl)-1,6-heptadiene-3,5-dione (1a), 1,7-di(2-methoxy 1-naphthyl)-1,6-heptadiene-3,5-dione (1b), 1,7-di(2-hydroxy ...

  12. The preparation and characterization of novel human-like collagen metal chelates

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Chenhui; Sun, Yan [Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering Northwest University, Xi' an 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Xi' an 710069 (China); Wang, Yaoyu [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Xi' an 710069 (China); Luo, Yane, E-mail: luoyane@nwu.edu.cn [Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering Northwest University, Xi' an 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Xi' an 710069 (China); Fan, Daidi, E-mail: fandaidi@nwu.edu.cn [Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering Northwest University, Xi' an 710069 (China); Shaanxi R and D Center of Biomaterials and Fermentation Engineering, Xi' an 710069 (China)

    2013-07-01

    In order to develop the nutritional trace elements which could be absorbed and utilized effectively, protein chelates were adopted. Calcium, copper and manganese were considered based on their physiological functions, and the new chelates of HLC-Ca, HLC-Cu and HLC-Mn were formed in MOPS or MES buffer and purified by gel chromatography, and then freeze-dried. And they were detected and analyzed by atomic absorption spectrophotometry, ultraviolet–visible absorption (UV–vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, fluorescence quenching method, circular dichroism (CD) and differential scanning calorimetry (DSC). The results showed that some chemical reactions happened between HLC and the three metal ions to form new chemical compounds. The thermodynamic parameters, ∆H, ∆G and ∆S, showed that the chelation process between HLC and metal ions was performed spontaneously. Fluorescence quenching spectra of HLC indicated that the quenching mechanism was static in nature. According to the data of DSC, the new chelates were more stable than the free HLC. And HLC-metal complex was non-toxic to the BHK21 cell through MTT assay. - Highlights: ► HLC-Ca, HLC-Cu and HLC-Mn were new chemical compounds and different to free HLC. ► Possible sites for Ca{sup 2+}, Cu{sup 2+} and Mn{sup 2+} to bind with HLC were presented. ► The chelation process between HLC and metal ions was performed spontaneously. ► The thermodynamic stability of the new chelates was higher than that of free HLC.

  13. The preparation and characterization of novel human-like collagen metal chelates

    International Nuclear Information System (INIS)

    In order to develop the nutritional trace elements which could be absorbed and utilized effectively, protein chelates were adopted. Calcium, copper and manganese were considered based on their physiological functions, and the new chelates of HLC-Ca, HLC-Cu and HLC-Mn were formed in MOPS or MES buffer and purified by gel chromatography, and then freeze-dried. And they were detected and analyzed by atomic absorption spectrophotometry, ultraviolet–visible absorption (UV–vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, fluorescence quenching method, circular dichroism (CD) and differential scanning calorimetry (DSC). The results showed that some chemical reactions happened between HLC and the three metal ions to form new chemical compounds. The thermodynamic parameters, ∆H, ∆G and ∆S, showed that the chelation process between HLC and metal ions was performed spontaneously. Fluorescence quenching spectra of HLC indicated that the quenching mechanism was static in nature. According to the data of DSC, the new chelates were more stable than the free HLC. And HLC-metal complex was non-toxic to the BHK21 cell through MTT assay. - Highlights: ► HLC-Ca, HLC-Cu and HLC-Mn were new chemical compounds and different to free HLC. ► Possible sites for Ca2+, Cu2+ and Mn2+ to bind with HLC were presented. ► The chelation process between HLC and metal ions was performed spontaneously. ► The thermodynamic stability of the new chelates was higher than that of free HLC

  14. Effect of the chelation of metal cation on the antioxidant activity of chondroitin sulfates.

    Science.gov (United States)

    Ajisaka, Katsumi; Oyanagi, Yutaka; Miyazaki, Tatsuo; Suzuki, Yasuhiro

    2016-06-01

    The antioxidant potencies of chondroitin sulfates (CSs) from shark cartilage, salmon cartilage, bovine trachea, and porcine intestinal mucosa were compared by three representative methods for the measurement of the antioxidant activity; DPPH radical scavenging activity, superoxide radical scavenging activity, and hydroxyl radical scavenging activity. CSs from salmon cartilage and bovine trachea showed higher potency in comparison with CSs from shark cartilage and porcine intestinal mucosa. Next, CS from salmon cartilage chelating with Ca(2+), Mg(2+), Mn(2+), or Zn(2+) were prepared, and their antioxidant potencies were compared. CS chelating with Ca(2+) or Mg(2+) ions showed rather decreased DPPH radical scavenging activity in comparison with CS of H(+) form. In contrast, CS chelating with Ca(2+) or Mg(2+) ion showed remarkably enhanced superoxide radical scavenging activity than CS of H(+) or Na(+) form. Moreover, CS chelating with divalent metal ions, Ca(2+), Mg(2+), Mn(2+), or Zn(2+), showed noticeably higher hydroxyl radical scavenging activity than CS of H(+) or Na(+) form. The present results revealed that the scavenging activities of, at least, superoxide radical and hydroxyl radical were enhanced by the chelation with divalent metal ions. PMID:26856546

  15. Metal Ions Extraction with Glucose Derivatives as Chelating Reagents in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    Guo Chen YANG; Hai Jian YANG

    2006-01-01

    A series of glucose derivatives have been used as chelating reagents to extract metal ions in supercritical carbon dioxide. With perfluoro-1-octanesulfonic acid tetraethylammonium salt as additive, glucose derivatives were selective for Sr2+ and Pb2+ extraction in supercritical carbon dioxide.

  16. High-performance chelation chromatography of metal ions on sorbents with grafted iminodiacetic acid

    International Nuclear Information System (INIS)

    Chromatographic behavior of some alkaline earth, transition, heavy (including uranium) and rare earth metal ions on a group of complexing sorbents, containing surface functional groups of imidodiacetic acid, was studied. Conditions, under which metal retention is determined by complexing on the sorbent surface, were defined and main principles of a new variant of liquid chromatography, i.e. high-performance chelating chromatography of metal ions (HPCCI) were formulated. It is shown that under optimal conditions metal retention correlates linearly in bilogarithmic coordinates with stability constants of the relevant metal complexes. Potentialities of HPCCI analytic application to analysis of objects featuring complex composition were considered

  17. The influence of the chelated metal ion on the fragmentation pathways of metal complexes of 5-nitro-octaethylporphyrin

    International Nuclear Information System (INIS)

    Tandem mass spectrometric analyses of suite of 10 divalent complexes of 5-nitro-octaethylporphyrin reveals that the fragmentation pathway is influenced by the chelated metal ion. The porphyrins undergo a novel cleavage of the macrocyclic ring. Surprisingly, the expected β-cleavage of the alkyl substituents is not very significant for many of the complexes. In this paper the mass spectra of the metalloporphyrins are compared and the role of the chelated metal ion will be discussed. The effect of the rate of heating on the mass spectra of the molecules will also be discussed

  18. Direct measurement of metal ion chelation in the active site of human ferrochelatase†

    OpenAIRE

    Hoggins, M.; Dailey, H. A.; Hunter, C.N.; Reid, J. D.

    2007-01-01

    The final step in heme biosynthesis, insertion of ferrous iron into protoporphyrin IX, is catalyzed by protoporphyrin IX ferrochelatase (E.C. 4.99.1.1). It is demonstrated that the pre-steady state human ferrochelatase (R115L) shows a stoichiometric burst of product formation and substrate consumption, consistent with a rate determining step following metal-ion chelation. Detailed analysis shows that chelation requires at least two steps, rapid binding followed by a slower (k ca. 1 s−1) irrev...

  19. Chelation in metal intoxication X: influence of different polyaminocarboxylic acids and thiol chelators in the excretion and tissue distribution of 54Mn in rat

    International Nuclear Information System (INIS)

    The influence of some selected polyaminocarboxylic acids and thiol metal binding agents on the urinary and faecal excretions of 54Mn and on the tissue distribution of 54Mn in 54MnC12 administered rats was studied to find a suitable chelating drug for Mn poisoning. HEDTA, CDTA, DTPA and TTHA were highly successful in enhancing the excretion of 54Mn and reducing the tissue levels of 54Mn in rats. The thiol chelators viz. D L-penicillamine, N-acetyl D L-penicillamine and DMS could neither influence the excretion nor the tissue distribution of 54Mn suggesting poor affinity of the metal towards sulfhydryl groups

  20. Heavy Metal Displacement in Chelate-Assisted Phytoremediation of Biosolids Soil

    Science.gov (United States)

    Kirkham, M. B.; Liphadzi, M. S.

    2005-05-01

    Heavy metals in biosolids (sewage sludge) applied to land contaminate the soil. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with biosolids following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals, as affected by a chelate, in soil (Haynie very fine sandy loam) from a 25-year old sludge farm. Soil columns (105 cm long; 39 cm in diameter) either had a plant (hybrid poplar; Populus deltoides Marsh. x P. nigra L.) or no plant. When the poplars were 144 days old, the tetrasodium salt of the chelating agent EDTA (ethylenediamine-tetraacetic acid) was irrigated onto the soil at a rate of 1 g per kg of soil. Drainage water, soil, and plants were analyzed for three toxic heavy metals (Cd, Ni, Pb) and four essential heavy metals (Cu, Fe, Mn, Zn). Without EDTA, concentrations of the seven heavy metals in the leachate from columns with or without plants were low or below detection limits. With or without plants, the EDTA mobilized all heavy metals and increased their concentration in drainage water. Without plants, the concentrations of Cd, Cu, Fe, Pb, and Zn in the leachate from columns with EDTA were above drinking-water standards. (There is no drinking-water standard for Ni.) The presence of poplar plants in the soil reduced the concentrations of Cu, Fe, and Zn in the leachate so it fell within drinking-water standards. Concentrations of Cd and Pb in the leachate remained above drinking-water standards with or without plants. At harvest (124 days after the EDTA application), total concentration of each heavy metal in the soil at different depths in the columns with EDTA was similar to that in the columns without EDTA. The chelate did not affect the concentration of heavy metals in the roots, stems, or leaves

  1. The phospholipid vesicles coating on metal chelated inorganic surfaces

    International Nuclear Information System (INIS)

    This work showed the formation of phospholipid vesicle coating on inorganic sericite surface with characterization by combining electron microscopy of FE-SEM, TEM, AFM, and qualitatively evaluated the coated phospholipid vesicle by XPS as a function of etching time. The possibility of phospholipid vesicle mobility on the surface was restrained by the chelation effect of magnesium cation. The stabilization properties of phospholipid vesicles on sericite surface were demonstrated by the various concentration of magnesium cation. The presence of magnesium was found to have a much more pronounced influence on the lipid deposition process. The Mg cation plays an important role for attaching the phospholipids with optimum concentration of 7 mM. Totally, the phospholipid vesicles coating on inorganic powder could be useful for bio-related fields such as cosmetics and drug delivery system as the key functional compounds. We hope this basic result lead to a general and simple approach to prepare a wide a range of controlled releasing materials including an encapsulation with cosmetics or drugs

  2. Synthesis, Characterization, and Application of Metal-Chelating Polymers for Mass Cytometric Bioassays

    Science.gov (United States)

    Majonis, Daniel

    This thesis describes the synthesis, characterization, and application of metal-chelating polymers for mass-cytometric bioassays. Mass cytometry is a cell characterization technique in which cells are injected individually into an ICP-MS detector. Signal is provided by staining cell-surface or intracellular antigens with metal-labeled antibodies (Abs). These Abs are labeled through the covalent attachment of metal-chelating polymers which carry multiple copies of a lanthanide isotope. In this work, my first goal was to develop a facile, straightforward synthesis of a new generation of metal-chelating polymers. The synthesis began with reversible addition-fragmentation chain transfer polymerization, and was followed by numerous post-polymerization pendant group transformations to introduce DTPA lanthanide chelators to every repeat unit, and a maleimide at the end of the chain. The second goal was to apply these metal-chelating polymers in bioassay experiments. The DTPA groups were loaded with lanthanide ions, and the maleimide group was used to covalently attach the polymer to an Ab. This goat anti-mouse conjugate was found to carry an average of 2.4 +/- 0.3 polymer chains. Then, primary Ab conjugates were prepared and used in an 11-plex mass cytometry assay in the characterization of umbilical cord blood cells. The third goal was to expand the multiplexity of the assay. In current technology, the number of Abs that can be monitored simultaneously is limited to the 31 commercially available, stable lanthanide isotopes. Thus, I had an interest in preparing metal-chelating polymers that could carry other metals in the 100-220 amu range. I synthesized polymers with four different polyaminocarboxylate ligands, and investigated the loading of palladium and platinum ions into these polymers. Polymer-Ab conjugates prepared with palladium- and platinum-loaded polymers gave curious results, in that only dead cells were recognized. The fourth goal was to create dual

  3. Group 4 Metal Complexes of Chelating Cyclopentadienyl-ketimide Ligands

    Czech Academy of Sciences Publication Activity Database

    Večeřa, M.; Varga, Vojtěch; Císařová, I.; Pinkas, Jiří; Kucharczyk, P.; Sedlařík, V.; Lamač, Martin

    2016-01-01

    Roč. 35, č. 5 (2016), s. 785-798. ISSN 0276-7333 R&D Projects: GA ČR(CZ) GA14-08531S; GA MŠk(CZ) LO1504 Institutional support: RVO:61388955 Keywords : group 4 metal complexes * cyclopentadienyl-ketimide ligands * metallocenes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.126, year: 2014

  4. Biological activity of ellagitannins: Effects as anti-oxidants, pro-oxidants and metal chelators.

    Science.gov (United States)

    Moilanen, Johanna; Karonen, Maarit; Tähtinen, Petri; Jacquet, Rémi; Quideau, Stéphane; Salminen, Juha-Pekka

    2016-05-01

    Ellagitannins are a subclass of hydrolysable tannins that have been suggested to function as defensive compounds of plants against herbivores. However, it is known that the conditions in the digestive tracts of different herbivores are variable, so it seems reasonable to anticipate that the reactivities and modes of actions of these ingested defensive compounds would also be different. A previous study on a few ellagitannins has shown that these polyphenolic compounds are highly oxidizable at high pH and that their bioactivity can be attributed to certain structural features. Herein, the activities of 13 ellagitannins using the deoxyribose assay were measured. The results provided information about the anti-oxidant, pro-oxidant and metal chelating properties of ellagitannins. Surprisingly, many of the tested ellagitannins exhibited pro-oxidant activities even at neutral pH and only moderate to low radical scavenging activities, although the metal chelating capacities of all tested ellagitannins were relatively high. PMID:26899362

  5. FTIR, magnetic, mass spectral, XRD and thermal studies of metal chelates of tenoxicam

    Science.gov (United States)

    Zayed, M. A.; El-Dien, F. A. Nour; Mohamed, Gehad G.; El-Gamel, Nadia E. A.

    2007-09-01

    Metal chelates of anti-inflammatory drug, tenoxicam (Ten), are synthesized and characterized using elemental analyses, IR, solid reflectance, magnetic, mass spectra, thermal analyses (TGA and DTA) and X-ray powder diffraction techniques. The chelates are found to have the general formulae [M(H 2L) 2(H 2O) x] (A) 2· yH 2O (where H 2L = neutral Ten, A = Cl in case of Ni(II) and Co(II) or AcO in case of Cu(II) and Zn(II) ions, x = 0-2 and y = 0-2.5) and [M(H 2L) 3](A) z· yH 2O (A = SO 4 in case of Fe(II) ion ( z = 1) or Cl in case of Fe(III) ( z = 3) and y = 0-4). IR spectra reveal that Ten behaves as a neutral bidentate ligand coordinated to the metal ions through the pyridyl- N and carbonyl- O of the amide moiety. The solid reflectance spectra and magnetic moment measurements reveal that these chelates have tetrahedral, square planar and octahedral geometrical structures. Mass spectra are also used to confirm the proposed formulae and the possible fragments resulted from fragmentation of Ten and its Zn(II) and Cu(II) chelates are suggested. The thermal behaviour of the chelates (TG/DTG, DTA) are discussed in detailed manner and revealed that water molecules of crystallization together with anions are removed in the first and second steps while the Ten molecules are removed in the subsequent steps. Different thermodynamic parameters are evaluated and the relative thermal stabilities of the complexes are discussed. X-ray powder diffraction patterns are used to indicate the polymorphic form of Ten and if the complexes have molecular similarity with respect to type of coordination.

  6. Selective Chemical Labeling of Proteins with Small Fluorescent Molecules Based on Metal-Chelation Methodology

    OpenAIRE

    Nobuaki Soh

    2008-01-01

    Site-specific chemical labeling utilizing small fluorescent molecules is a powerful and attractive technique for in vivo and in vitro analysis of cellular proteins, which can circumvent some problems in genetic encoding labeling by large fluorescent proteins. In particular, affinity labeling based on metal-chelation, advantageous due to the high selectivity/simplicity and the small tag-size, is promising, as well as enzymatic covalent labeling, thereby a variety of novel methods have been stu...

  7. Protection against SR 4233 (tirapazamine) aerobic cytotoxicity by the metal chelators desferrioxamine and tiron

    International Nuclear Information System (INIS)

    Metal chelating agents and antioxidants were evaluated as potential protectors against aerobic SR 4233 cytotoxicity in Chinese hamster V79 cells. The differential protection of aerobic and hypoxic cells by two metal chelators, desferrrioxamine and Tiron, is discussed in the context of their potential use in the on-going clinical trials with SR 4233. Cytotoxicity was evaluated using clonogenic assay. SR 4233 exposure was done in glass flasks as a function of time either alone or in the presence of the following agents: superoxide dismutase, catalase, 5,5-dimethyl-1-pyrroline, Trolox, ICRF-187, desferrioxamine, Tiron (1,2-dihydroxybenzene-3,5-disulfonate), and ascorbic acid. Experiments done under hypoxic conditions were carried out in specially designed glass flasks that were gassed with humidified nitrogen/carbon dioxide mixture and with a side-arm reservoir from which SR 4233 was added to cell media after hypoxia was obtained. Electron paramagnetic resonance studies were also performed. Electron paramagnetic resonance and spectrophotometry experiments suggest that under aerobic conditions SR 4233 undergoes futile redox cycling to produce superoxide. Treatment of cells during aerobic exposure to SR 4233 with the enzymes superoxide dismutase and catalase, the spin trapping agent DMPO, the water-soluble vitamin E analog Trolox, and the metal chelator ICRF-187 provided little or no protection against aerobic SR 4233 cytotoxicity. However, two other metal chelators, desferrioxamine and Tiron afforded significant protection against minimal protection to hypoxic cells treated with SR 4233. One potential mechanism of aerobic cytotoxicity is redox cycling of SR 4233 with molecular oxygen resulting in several potentially toxic oxidative species that overburden the intrinsic intracellular detoxification systems such as superoxide dismutase, catalase, and glutathione peroxidase. 23 refs., 4 figs., 1 tab

  8. Synthesis of a Functional Metal-Chelating Polymer and Steps towards Quantitative Mass Cytometry Bioassays

    OpenAIRE

    Majonis, Daniel; Herrera, Isaac; Ornatsky, Olga; Schulze, Maren; Lou, Xudong; Soleimani, Mohsen; Nitz, Mark; Mitchell A. Winnik

    2010-01-01

    We describe the synthesis and characterization of metal-chelating polymers with a degree of polymerization of 67 and 79, high DTPA functionality, Mw/Mn ≤ 1.17, and a maleimide as an orthogonal functional group for conjugation to antibodies. The polymeric disulfide form of the DPn = 79 DTPA polymer was analyzed by thermogravimetric analysis to determine moisture and sodium-ion content, and by isothermal titration calorimetry (ITC) to determine the Gd3+ binding capacity. These results showed ea...

  9. Use of non-hyperaccumulator plant species for the phytoextraction of heavy metals using chelating agents

    Directory of Open Access Journals (Sweden)

    Lucas Anjos Souza

    2013-08-01

    Full Text Available Soil contamination by heavy metals is a challenge faced by many countries, and engineering technologies to solve this problem are expensive and can cause negative impacts on the environment. One way to minimise the levels of heavy metals in the soil is to use plants that can absorb and accumulate heavy metals into harvestable parts, a process called phytoextraction. Typical plant species used in research involving phytoextraction are heavy metal hyperaccumulators, but plants from this group are not good biomass producers and grow more slowly than most species; thus, they have an important role in helping scientists understand the mechanisms involved in accumulating high amounts of heavy metals without developing symptoms or dying. However, because of their slow growth, it is not practical to use these species for phytoextraction. An alternative approach is to use non-hyperaccumulator plants assisted by chelating agents, which may improve the ability of plants to accumulate more heavy metals than they would naturally. Chelating agents can be synthetic or organic acids, and the advantages and disadvantages of their use in improving the phytoextraction potential of non-hyperaccumulator plants are discussed in this article. We hope to draw attention to ways to improve the phytoextraction potential of non-hyperaccumulator plants that produce a large amount of biomass and to stimulate more research on phytoextraction-inducing substances.

  10. DESORPTION OF METAL IONS FROM KRAFT PULPS. PART 1. CHELATION OF HARDWOOD AND SOFTWOOD KRAFT PULP WITH EDTA

    OpenAIRE

    Kim Granholm; Leo Harju; Ari Ivaska

    2010-01-01

    Chelation of unbleached and oxygen bleached hardwood and softwood kraft pulps with EDTA was studied. The main focus was on the desorption of magnesium, manganese, and iron due to their impact in TCF-bleaching. Desorption of other metal ions present were also studied in order to get an over-all estimation of the metal ion concentrations and their desorption during chelation. By using the concept of side reaction coefficients, an estimation of the chelating strength of EDTA at different pH can ...

  11. Fabrication of chelating diethylenetriaminated pan micro and nano fibers for heavy metal removal

    Directory of Open Access Journals (Sweden)

    Abdouss Majid

    2012-01-01

    Full Text Available In this study, commercial acrylic fibers were modified with diethylenetriamine to prepare metal chelating fibers. The effects of process parameters on the efficiency of the reaction were investigated. FTIR spectroscopy and TGA analysis were used to confirm the chemical changes made to the fibers during the reaction. The ability of the modified fibers for removal of Pb (II, Cu (II and Ce (IV ions from aqueous media was determined. The modified fibers showed a slight decrease in mechanical properties compared to raw ones. Furthermore, the acrylic micro fibers were electrospun to nanofibers and the ability of modified nanofibers for the adsorption of the metal ions was studied.

  12. Heavy metal ion uptake properties of polystyrene-supported chelating polymer resins

    Indian Academy of Sciences (India)

    A Ravikumar Reddy; K Hussain Reddy

    2003-06-01

    Metal ion uptake properties of polystyrene-supported chelating polymer resins functionalized with (i) glycine, (ii) hydroxy benzoic acid, (iii) Schiff base and (iv) diethanol amine have been investigated. The effects of pH, time and initial concentration on the uptake of metal ions have been studied. The uptake of metal ion depends on pH. The resins are more selective at pH 10 for Pb(II) and Hg(II), whereas at pH 6 they are found to be Cd(II) and Cr(VI) selective. Metal ion uptake properties of resins follow Freundlich’s equation. The resins are recyclable and are therefore employed for the removal of heavy metal pollutants from industrial waste water.

  13. Compositional analysis of metal chelating materials using near-field photothermal Fourier transform infrared microspectroscopy.

    Science.gov (United States)

    Moffat, Jonathan G; Mayes, Andrew G; Belton, Peter S; Craig, Duncan Q M; Reading, Mike

    2010-01-01

    Photothermal-Fourier transform-infrared (PT-FT-IR) microspectroscopy employs a thermal probe mounted in a scanning probe microscope (SPM). By placement of the tip of the probe on the surface of a solid sample, it can obtain localized IR spectra of a wide range of samples. A second mode of analysis is also available; a sample can be taken from the selected location using a technique called thermally assisted nanosampling (TAN), then a spectrum can be obtained of the nanosample while the probe is remote from the surface. We report a novel method of local compositional analysis that combines both of these types of measurement; a reagent is attached to the tip using TAN, then the reagent is placed in contact with analyte. IR spectroscopy can then be used to analyze any interaction between the reagent and surface it is placed in contact with. All of these modes of analysis were illustrated using a metal chelating agent. In the surface mode, changes to a solid bead of a chelating resin were measured using standard PT-FT-IR. In the nanosampling mode of analysis, a particle of a chelating polymer was attached to the tip of the probe using TAN and this was placed in contact with a concentrated calcium solution. Strong spectral changes were observed that mirrored those found when exposing the surface bound chelating resin bead to a solution of the same ion. A semiquantitative simulation of the PT spectrum for a chelating resin bead was achieved using a thermal diffusion model derived from photoacoustic spectroscopy indicating that semiquantitative or quantitative measurements will be possible in such a system. PMID:19957959

  14. Metal chelate affinity precipitation of RNA and purification of plasmid DNA

    Science.gov (United States)

    Balan, Sindhu; Murphy, Jason; Galaev, Igor; Kumar, Ashok; Fox, George E.; Mattiasson, Bo; Willson, Richard C.

    2003-01-01

    The affinity of metal chelates for amino acids, such as histidine, is widely used in purifying proteins, most notably through six-histidine 'tails'. We have found that metal affinity interactions can also be applied to separation of single-stranded nucleic acids through interactions involving exposed purines. Here we describe a metal affinity precipitation method to resolve RNA from linear and plasmid DNA. A copper-charged copolymer of N-isopropyl acrylamide (NIPAM) and vinyl imidazole (VI) is used to purify plasmid from an alkaline lysate of E. coli. The NIPAM units confer reversible solubility on the copolymer while the imidazole chelates metal ions in a manner accessible to interaction with soluble ligands. RNA was separated from the plasmid by precipitation along with the polymer in the presence of 800 mM NaCl. Bound RNA could be recovered by elution with imidazole and separated from copolymer by a second precipitation step. RNA binding showed a strong dependence on temperature and on the type of buffer used.

  15. Synthesis and characterisation of 8-hydroxyquinoline-bovine serum albumin conjugates as metal ion chelating proteins

    International Nuclear Information System (INIS)

    A derivative of 8-hydroxyquinoline (8-quinolinol, oxine) with a linking bridge containing a carboxylic group was covalently coupled to bovine serum albumin by the N-hydroxysuccinimide method to obtain stable monomeric conjugates with oxine to protein mole ratios up to 37. These conjugates were characterised spectrophotometrically and their complexation properties were confirmed by spectral analysis with and without the addition of Al(III), Cd(II), Co(II), Cu(II), Hg(II), Mn(II), Ni(II), Pb(II), V(IV), U(VI) and Zn(II) ions added. The maximum number of ions bound by these chelating proteins was determined spectrophotometrically by titration with metal ions at pH 6.0. The conjugates with a substitution ratio (moles of 8-hydroxyquinoline bound/mole of albumin) less than about 8 showed 1:1 binding with metal ions, while conjugates with higher substitution ratios were able to complex with 2:1 ratio of 8-hydroxyquinoline to metal ion. Association and dissociation kinetics of complexation with copper(II) ions showed a complex mechanism. The spectral and binding properties of these metal ion-binding proteins confirm that the coupling of the 8-hydroxyquinoline derivative to bovine serum albumin gives stable, water soluble, macromolecular chelating agents that retain the complexing ability of the original ligand. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  16. Leaching heavy metals in municipal solid waste incinerator fly ash with chelator/biosurfactant mixed solution.

    Science.gov (United States)

    Xu, Ying; Chen, Yu

    2015-07-01

    The chelator [S,S]-ethylene diamine disuccinic acid, citric acid, and biosurfactant saponin are selected as leaching agents. In this study, the leaching effect of saponin mixed with either ethylene diamine disuccinic acid or citric acid on the levels of copper, zinc, lead, and cadmium in municipal solid waste incinerator fly ash is investigated. Results indicate that saponin separately mixed with ethylene diamine disuccinic acid and citric acid exhibits a synergistic solubilisation effect on copper, zinc, lead, and cadmium leaching from fly ash. However, saponin and ethylene diamine disuccinic acid mixed solution exhibits a synergistic solubilisation effect that is superior to that of a saponin and citric acid mixed solution. The extraction rate of heavy metal in fly ash leached with a saponin and chelator mixed solution is related to the pH of the leaching solution, and the optimal range of the pH is suggested to be approximately neutral. After leaching with a saponin and chelator mixed solution, copper, zinc, lead, and cadmium contents significantly decreased (p leaching concentrations of copper, zinc, lead, and cadmium in treated fly ash are in accordance with Standard for Pollution Control on the Security Landfill Site for Hazardous Wastes GB18598-2001. PMID:26185165

  17. Metal-ion chelation chromatography on silica-immobilized 8-hydroxyquinoline

    International Nuclear Information System (INIS)

    A chromatographically useful packing is prepared by immobilizing 8-hydoxyquinoline on Porasil. This material, whose capacity is about 50 μequiv/g, behaves with an efficiency of about 0.2 to 0.5 mm/theoretical plate but is capable of separating such similar metal ions as Co-Ni, Cd-Pb-Zn, and La-Gd-Yb at trace levels employing both isocratic and continuous gradient elution. On a fundamental level, the relationship between solution chelate stability and chromatographic behavior is described. 9 figures, 2 tables

  18. Meso-2,3-dimercaptosuccinic acid: from heavy metal chelation to CdS quantum dots

    OpenAIRE

    Sevinç, Esra; Ertaş, F. Sinem ; Ulusoy, Gülen ; Acar, Havva Yağcı; Özen, Can

    2012-01-01

    DMSA (meso-2,3-dimercaptosuccinic acid) a prescription drug and a heavy-metal chelating agent, is shown to act both as a sulfur source and a capping agent in the aqueous synthesis of CdS quantum dots under mild conditions. Release of sulfur from DMSA depends on the solution pH and the reaction temperature. Combination of 70 C and pH 7.5 was determined as the best reaction conditions for a well-controlled reaction. Changing the SH/Cd ratio from 2.5 to 7 provides QDs emitting from ...

  19. Synthesis, characterization and biological studies of 1,7- dinaphthyl heptanoids and their metal chelates

    Directory of Open Access Journals (Sweden)

    S. Sindhu

    2015-06-01

    Full Text Available The present investigation includes the synthesis, characterization, antitumour and antimicrobial activities of three new curcuminoid analogues and their metal chelates. Curcuminoid analogues and their metal chelates have great ability to act as antitumour and antimicrobial agents which motivated us and lead to this present work. The new curcuminoid analogues namely 1,7-di(1-naphthyl-1,6-heptadiene-3,5-dione (1a, 1,7-di(2-methoxy 1-naphthyl-1,6-heptadiene-3,5-dione (1b, 1,7-di(2-hydroxy 1-naphthyl-1,6 -heptadiene-3,5-dione and their Cu(II and Al(III complexes were synthesized and characterized using UV, IR,1HNMR and Mass spectral data. The curcuminoid analogues and their metal complexes were studied for their cytotoxicity and antibacterial ability using Trypan blue exclusion method and agar well diffusion method respectively. The present study suggests that the Cu(II complexs showed remarkable enhancement of cytotoxic activity where as the Al(III complexs were found to be most active towards antimicrobial activity.

  20. Immobilization of heavy metals on pillared montmorillonite with a grafted chelate ligand

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Loren; Seaton, Kenneth; Mohseni, Ray; Vasiliev, Aleksey, E-mail: vasiliev@etsu.edu

    2013-10-15

    Highlights: • Mesoporous organoclay for immobilization of heavy metal cations was obtained. • The material has a porous structure with high contents of surface adsorption sites. • Leaching of heavy metals from soil reduced in the presence of this adsorbent. • The adsorbent demonstrated high effectiveness in neutral and acidic media. -- Abstract: The objective of this work was the development of an efficient adsorbent for irreversible immobilization of heavy metals in contaminated soils. The adsorbent was prepared by pillaring of montmorillonite with silica followed by grafting of a chelate ligand on its surface. Obtained adsorbent was mesoporous with high content of adsorption sites. Its structure was studied by BET adsorption of N{sub 2}, dynamic light scattering, and scanning electron microscopy. The adsorption capacity of the organoclay was measured by its mixing with contaminated kaolin and soil samples and by analysis of heavy metal contents in leachate. Deionized water and 50% acetic acid were used for leaching of metals from the samples. As it was demonstrated by the experiments, the adsorbent was efficient in immobilization of heavy metals not only in neutral aqueous media but also in the presence of weak acid. As a result, the adsorbent can be used for reduction of heavy metal leaching from contaminated sites.

  1. Metal distribution and spectroscopic analysis after soil washing with chelating agents and humic substances.

    Science.gov (United States)

    Tsang, Daniel C W; Hartley, Neil R

    2014-03-01

    Biodegradable chelating agents ([S,S]-ethylenediamine-N,N-disuccinic acid (EDDS) and glutamic-N,N-diacetic acid (GLDA)) and natural humic substances (lignite-derived, standard, and commercially available humic acids) are potentially useful for enhancing soil remediation of timber treatment sites. This study integrated macroscopic and spectroscopic analyses to assess their influence on the distribution and chemical speciation of the remaining metals as well as their interaction with the soil surface after 48-h washing of a field-contaminated soil. The results demonstrated that EDDS and GLDA were an appealing alternative to non-biodegradable ethylenediamine-tetraacetic acid, but the three humic substances were less effective. As shown by sequential extractions, Cu was primarily extracted from the carbonate fraction while Cr and As extraction resulted from (co-)dissolution of the oxide fraction. As a result, the relative proportion of strongly bound organic matter and residual fractions increased by 7-16 %. However, it was noteworthy that the exchangeable fraction also increased by 5-11 %, signifying that a portion of the remaining metals was destabilized by chelating agents and transformed to be more labile in the treated soil. The X-ray photoelectron spectroscopy spectra confirmed the substantial removal of readily accessible Cu from the soil surface, but Cr maintained its original chemical forms of trivalent chromium oxides and iron-chromium coprecipitates, whereas As remained as arsenic trioxide/pentoxide and copper arsenate precipitates. On the other hand, the absence of characteristic peaks of adsorbed carboxylate groups in the Fourier-transform infrared (FTIR) spectra inferred that the extent of adsorption of chelating agents and humic substances on the bulk soil was insufficient to be characterized by FTIR analysis. These results suggested that attention should be paid to the exchangeable fraction of Cu and oxides/coprecipitates of As prior to possible on

  2. Solubility and accumulation of metals in Chinese brake fern, vetiver and rostrate sesbania using chelating agents.

    Science.gov (United States)

    Lou, L Q; Ye, Z H; Wong, M H

    2007-01-01

    Greenhouse experiments were conducted to study the effects of chelating agents on the growth and metal accumulation of Chinese brake fern (Pteris vittata L.), vetiver (Vetiveria zizanioides L.), and rostrate sesbania (Sesbania rostrata L.) in soil contaminated with arsenic (As), Cu, Pb, and Zn. Among the five chelating agents used [ethylenediaminetriacetic acid (EDTA), hydroxyethylenediaminetriacetic acid (HEDTA), nitrilotriacetic acid (NTA), oxalic acid (OA), and phytic acid (PA)], OA was the best to mobilize As, EDTA to mobilize Cu and Pb, and HEDTA to mobilize Zn from soil, respectively. The biomass of vetiver was the highest, followed by rostrate sesbania. All chelating agents inhibited the growth of Chinese brake fern and rostrate sesbania, but HEDTA significantly increased the aboveground biomass of vetiver. Dry weights of both Chinese brake fern and rostrate sesbania decreased with increasing EDTA concentrations amended in the soil, especially in treatments with high EDTA concentrations. EDTA and HEDTA enhanced Cu, Zn, and Pb, but lowered As accumulation in all three plant species, except for As in vetiver, while OA significantly enhanced As accumulation in the aboveground part of vetiver. Concentrations of Cu, Zn, and Pb in the aboveground parts of plants increased significantly with the increase of EDTA concentrations and treatment time. In addition to As, Chinese brake fern also accumulated the highest Cu, Pb, and Zn in its aboveground parts among the three plant species grown in metal-contaminated soil with EDTA/HEDTA treatments. This species, therefore, can be used to simultaneously clean up As, Cu, Pb, and Zn from contaminated soils with the aid of EDTA or HEDTA. PMID:18246709

  3. Competition of dipositive metal ions for Fe (III) binding sites in chelation therapy of Iron Load

    International Nuclear Information System (INIS)

    Iron overload is a condition in which excessive iron deposited in the liver, kidney and spleen of human beings in the patients of beta thalassemia and sickle cell anemia. Instead of its importance iron could be toxic when in excess, it damages the tissues. For the treatment of iron overload, a drug desferrioxamine mesylate has been used. It is linear trihydroxamic acid, a natural siderophore produced by streptomyces which removes the extra iron from body. Salicylhydroxamate type siderphore. In present research salicylhydroxamate was used for the complexation with dipositive metal ions which are available in biological environments such as Mn (II), Co (II), Ni (II) and Cu (II). The aim of our work was to study the competition reactions between Fe (III) and other dipositive ions; to calculate the thermodynamic data of chelation of these metal ions complexes with hydroxamate by computer program and comparison with hydroxamate complexes. (author)

  4. Fast removal of heavy metal ions and phytic acids from water using new modified chelating fiber

    Institute of Scientific and Technical Information of China (English)

    Li Xu; Jin Nan Wang; Ying Meng; Ai Min Li

    2012-01-01

    The graft copolymerization of acrylic acid (AA) onto polyethylene glycol terephthalate (PET) fiber initiated by benzoy peroxide (BPO) was carried out in heterogeneous media.Moreover,modification of the grafted PET fiber (PET-AA) was done by changing the carboxyl group into acylamino group through the reaction with dimethylamine.The modified chelating fiber (NDWJN 1) was characterized using elementary analysis,SEM and FT-IR spectroscopy.Adsorption kinetic curves indicated that NDWJN1 could fast remove heavy metal ions and phytic acids from water effectively.Furthermore,batch kinetic studies indicated that heavy metal ions adsorbed to NDWJN1 could be fitted well by both pseudo-first-order and pseudo-second-order adsorption equations,but the intra-particle diffusion plaved a dominant role in the adsorption of phvtic acids.

  5. Effective removal of heavy metals from industrial sludge with the aid of a biodegradable chelating ligand GLDA

    International Nuclear Information System (INIS)

    Highlights: • A novel readily biodegradable chelating ligand was employed to remove heavy metals. • The effects of different conditions on the extraction with GLDA were probed. • Species distribution of metals before and after extraction with GLDA was analyzed. • GLDA was effective for Cd extraction from sludge samples under various conditions. • GLDA offers special insights in the effective removal of heavy metals. - Abstract: Tetrasodium of N,N-bis(carboxymethyl) glutamic acid (GLDA), a novel readily biodegradable chelating ligand, was employed for the first time to remove heavy metals from industrial sludge generated from a local battery company. The extraction of cadmium, nickel, copper, and zinc from battery sludge with the presence of GLDA was studied under different experimental conditions such as contact times, pH values, as well as GLDA concentrations. Species distribution of metals in the sludge sample before and after extraction with GLDA was also analyzed. Current investigation showed that (i) GLDA was effective for Cd extraction from sludge samples under various conditions. (ii) About 89% cadmium, 82% nickel and 84% copper content could be effectively extracted at the molar ratio of GLDA:M(II) = 3:1 and at pH = 4, whereas the removal efficiency of zinc was quite low throughout the experiment. (iii) A variety of parameters, such as contact time, pH values, the concentration of chelating agent, stability constant, as well as species distribution of metals could affect the chelating properties of GLDA

  6. 8-Hydroxyquinolines: a review of their metal chelating properties and medicinal applications

    Directory of Open Access Journals (Sweden)

    Prachayasittikul V

    2013-10-01

    Full Text Available Veda Prachayasittikul,1 Supaluk Prachayasittikul,2 Somsak Ruchirawat,3 Virapong Prachayasittikul11Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, 2Center of Data Mining and Biomedical Informatics, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand; 3Laboratory of Medicinal Chemistry, Chulabhorn Research Institute and Chulabhorn Graduate Institute, Bangkok, ThailandAbstract: Metal ions play an important role in biological processes and in metal homeostasis. Metal imbalance is the leading cause for many neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis. 8-Hydroxyquinoline (8HQ is a small planar molecule with a lipophilic effect and a metal chelating ability. As a result, 8HQ and its derivatives hold medicinal properties such as antineurodegenerative, anticancer, antioxidant, antimicrobial, anti-inflammatory, and antidiabetic activities. Herein, diverse bioactivities of 8HQ and newly synthesized 8HQ-based compounds are discussed together with their mechanisms of actions and structure–activity relationships.Keywords: metal binding compound, antineurodegenerative, anticancer, antidiabetic, multifunctional actions, structure–activity relationships

  7. Commentary on the Abuse of Metal Chelation Therapy in Patients with Autism Spectrum Disorders

    OpenAIRE

    Brent, Jeffrey

    2013-01-01

    Approximately half a million patients with autism spectrum disorders are subjected to chelation therapy in the US annually. The overwhelming majority of such cases are chelated for non-accepted medical indications. These patients may seek evaluation when a urine sample is assayed after the administration of a chelating agent and the values obtained have been improperly compared to references ranges for non-chelated urines, causing falsely elevated results. Legitimate practitioners confronted ...

  8. 'Unconventional' coordination chemistry by metal chelating fragments in a metalloprotein active site.

    Science.gov (United States)

    Martin, David P; Blachly, Patrick G; Marts, Amy R; Woodruff, Tessa M; de Oliveira, César A F; McCammon, J Andrew; Tierney, David L; Cohen, Seth M

    2014-04-01

    The binding of three closely related chelators: 5-hydroxy-2-methyl-4H-pyran-4-thione (allothiomaltol, ATM), 3-hydroxy-2-methyl-4H-pyran-4-thione (thiomaltol, TM), and 3-hydroxy-4H-pyran-4-thione (thiopyromeconic acid, TPMA) to the active site of human carbonic anhydrase II (hCAII) has been investigated. Two of these ligands display a monodentate mode of coordination to the active site Zn(2+) ion in hCAII that is not recapitulated in model complexes of the enzyme active site. This unprecedented binding mode in the hCAII-thiomaltol complex has been characterized by both X-ray crystallography and X-ray spectroscopy. In addition, the steric restrictions of the active site force the ligands into a 'flattened' mode of coordination compared with inorganic model complexes. This change in geometry has been shown by density functional computations to significantly decrease the strength of the metal-ligand binding. Collectively, these data demonstrate that the mode of binding by small metal-binding groups can be significantly influenced by the protein active site. Diminishing the strength of the metal-ligand bond results in unconventional modes of metal coordination not found in typical coordination compounds or even carefully engineered active site models, and understanding these effects is critical to the rational design of inhibitors that target clinically relevant metalloproteins. PMID:24635441

  9. Bioavailability assessment of metals chelated as proteinates using the Ussing Chamber Model

    Directory of Open Access Journals (Sweden)

    G. Piva

    2011-03-01

    Full Text Available Preparation of proteinates by hydrolysis of organic matter produces a blend of different proteins, and may likely result in the chelation of trace elements. Often this process results in an increased bioavailability of minerals, leading to a higher absorption rate than inorganic salts (Cao et al., 2000; Uchida et al., 2001; Bailey et al., 2001; Guo et al., 2001. Usually trace elements uptake takes place along the small intestine, mainly jejunum (Tapia et al., 1996; Arredondo et al., 2000, even if the precise mechanisms underlying transport are not well understood. If these complexes are formed among metals and amino acids, they could be easily transported across the intestinal membrane by amino acids carriers..............

  10. X-ray spectral study of structure of metal chelate dithiocarbamate complexes in solutions

    International Nuclear Information System (INIS)

    The structure of immediate surrounding of cadmium chelate dithiocarbamate complexes Cd[(C2H5)2NCS2]2 (or CdL2) and Cd[(n-C4H9)2NCS2]2 (or CdL21) in solutions of benzene, pyridine and tributylphosphine was studied by the EXAFS spectroscopy method using synchrotron radiation. When analyzing possible structure of cadmium complexes, two models were considered: monomeric and dimeric ones. It was ascertained that in benzene solutions there exist both dimeric and monomeric forms of CdL2. In pyridine solution coordination of nitrogen atom by cadmium atom both for CdL2 and CdL21 is observed. In solution of tributylphosphine coordination to metal of one or two phosphorus atoms with four sulfur atoms of ligand L1 is possible

  11. Emulsifier type, metal chelation and pH affect oxidative stability of n-3-enriched emulsions

    DEFF Research Database (Denmark)

    Haahr, Anne-Mette; Jacobsen, Charlotte

    2008-01-01

    Recent research has shown that the oxidative stability of oil-in-water emulsions is affected by the type of surfactant used as emulsifier. The aim of this study was to evaluate the effect of real food emulsifiers as well as metal chelation by EDTA and pH on the oxidative stability of a 10% n-3......-enriched oil-in-water emulsion. The selected food emulsifiers were Tween 80, Citrem, sodium caseinate and lecithin. Lipid oxidation was evaluated by determination of peroxide values and secondary volatile oxidation products. Moreover, the zeta potential and the droplet sizes were determined. Twen resulted...... in the least oxidatively stable emulsions, followed by Citrem. When iron was present, caseinate-stabilized emulsions oxidized slower than lecithin emulsions at pH 3, whereas the opposite was the case at pH 7. Oxidation generally progressed faster at pH 3 than at pH 7, irrespective of the addition of...

  12. Comparative study of antioxidant, metal chelating and antiglycation activities of Momordica charantia flesh and pulp fractions.

    Science.gov (United States)

    Ghous, Tahseen; Aziz, Nouman; Mehmood, Zahid; Andleeb, Saiqa

    2015-07-01

    Momordica charantia is commonly used as a vegetable and folk medicine in most parts of South Asia. This study aims to determine and compare the antioxidant, metal chelating and antiglycation activities of aqueous extracts of M. charantia fruit flesh (MCF) and fruit pulp (MCP) fractions. Our results show that MCP has pronounced DPPH and ABTS radical scavenging potential compared to MCF. In the antiglycation assay both fractions illustrated considerable inhibitory activities against the formation of AGEs induced by glucose with an efficacy of 75 and 67% with 150 μl of MCP and MCF extracts respectively, almost equal to 0.3mM amino guanidine. Results for metal catalysed protein fragmentation and autoxidative and glycoxidation assays demonstrate that MCF and MCP inhibited metal catalysed protein fragmentation. The percentage of relative standard deviation for three replicate measurements of 150 μl of MCF and MCP was < 3.0% for antiglycation. The antioxidant assays with regression values of MCP (0.981 and 0.991) and MCF (0.967 and 0.999) were also recorded. We conclude that both extracts possess high antioxidant and antiglycation activities and are equally good sources of antioxidant and antiglycating agents. PMID:26142512

  13. Chelation Therapy for Mercury Poisoning

    OpenAIRE

    Rong Guan; Han Dai

    2009-01-01

    Chelation therapy has been the major treatment for heavy metal poisoning. Various chelating agents have been developed and tested for treatment of heavy metal intoxications, including mercury poisoning. It has been clearly shown that chelating agents could rescue the toxicity caused by heavy metal intoxication, but the potential preventive role of chelating agents against heavy metal poisoning has not been explored much. Recent paper by Siddiqi and colleagues has suggested a protective role o...

  14. Bioinspired Immobilization of Glycerol Dehydrogenase by Metal Ion-Chelated Polyethyleneimines as Artificial Polypeptides

    Science.gov (United States)

    Zhang, Yonghui; Ren, Hong; Wang, Yali; Chen, Kainan; Fang, Baishan; Wang, Shizhen

    2016-01-01

    In this study, a novel, simple and generally applicable strategy for multimeric oxidoreductase immobilization with multi-levels interactions was developed and involved activity and stability enhancements. Linear polyethyleneimines (PEIs) are flexible cationic polymers with molecular weights that span a wide range and are suitable biomimic polypeptides for biocompatible frameworks for enzyme immobilization. Metal ion-chelated linear PEIs were applied as a heterofunctional framework for glycerol dehydrogenase (GDH) immobilization by hydrogen bonds, electrostatic forces and coordination bonds interactions. Nanoparticles with diameters from 250–650 nm were prepared that exhibited a 1.4-fold enhancement catalytic efficiency. Importantly, the half-life of the immobilized GDH was enhanced by 5.6-folds in aqueous phase at 85 °C. A mechanistic illustration of the formation of multi-level interactions in the PEI-metal-GDH complex was proposed based on morphological and functional studies of the immobilized enzyme. This generally applicable strategy offers a potential technique for multimeric enzyme immobilization with the advantages of low cost, easy operation, high activity reservation and high stability. PMID:27053034

  15. Removal of PCR error products and unincorporated primers by metal-chelate affinity chromatography.

    Directory of Open Access Journals (Sweden)

    Indhu Kanakaraj

    Full Text Available Immobilized Metal Affinity Chromatography (IMAC has been used for decades to purify proteins on the basis of amino acid content, especially surface-exposed histidines and "histidine tags" genetically added to recombinant proteins. We and others have extended the use of IMAC to purification of nucleic acids via interactions with the nucleotide bases, especially purines, of single-stranded RNA and DNA. We also have demonstrated the purification of plasmid DNA from contaminating genomic DNA by IMAC capture of selectively-denatured genomic DNA. Here we describe an efficient method of purifying PCR products by specifically removing error products, excess primers, and unincorporated dNTPs from PCR product mixtures using flow-through metal-chelate affinity adsorption. By flowing a PCR product mixture through a Cu(2+-iminodiacetic acid (IDA agarose spin column, 94-99% of the dNTPs and nearly all the primers can be removed. Many of the error products commonly formed by Taq polymerase also are removed. Sequencing of the IMAC-processed PCR product gave base-calling accuracy comparable to that obtained with a commercial PCR product purification method. The results show that IMAC matrices (specifically Cu(2+-IDA agarose can be used for the purification of PCR products. Due to the generality of the base-specific mechanism of adsorption, IMAC matrices may also be used in the purification of oligonucleotides, cDNA, mRNA and micro RNAs.

  16. Synthesis and evaluation of water-soluble chelating polymers for the selective removal of actinide metal ions

    International Nuclear Information System (INIS)

    A major goal of our research program is to develop polymer supported ion specific ligand systems for the removal of actinides and other hazardous metals from wastewaters. The advantage of water-soluble polymers in metal ion separation processes is that the homogeneity of the system allows for more rapid exchange kinetics than ion exchange or chelating resins. A number of water-soluble chelating polymers have been synthesized by the functionalization or commercially available polyamine precursors with various ligand moieties such as hydroxamates. The ability of these polymers to complex with metal ion to give soluble complexes which can be separated and concentrated by ultrafiltration under different pH conditions have been examined

  17. The Metal Chelators, Trientine and Citrate, Inhibit the Development of Cardiac Pathology in the Zucker Diabetic Rat

    Directory of Open Access Journals (Sweden)

    John W. Baynes

    2009-01-01

    Full Text Available Purpose. The objective of this study was to determine the efficacy of dietary supplementation with the metal chelators, trientine or citric acid, in preventing the development of cardiomyopathy in the Zucker diabetic rat. Hypothesis. We hypothesized that dietary chelators would attenuate metal-catalyzed oxidative stress and damage in tissues and protect against pathological changes in ventricular structure and function in type II diabetes. Methods. Animals (10 weeks old included lean control (LC, fa/+, untreated Zucker diabetic fatty (ZDF, fa/fa, and ZDF rats treated with either trientine (triethylenetetramine or citrate at 20 mg/d in drinking water, starting when rats were frankly diabetic. Cardiac functional assessment was determined using a Millar pressure/volume catheter placed in the left ventricle at 32 weeks of age. Results. End diastolic volume for the ZDF animals increased by 36% indicating LV dilatation (P<.05 and was accompanied by a 30% increase in the end diastolic pressure (P≤.05. Both trientine and citric acid prevented the increases in EDV and EDP (P<.05. Ejection fraction and myocardial relaxation were also significantly improved with chelator treatment. Conclusion. Dietary supplementation with trientine and citric acid significantly prevented structural and functional changes in the diabetic heart, supporting the merits of mild chelators for prevention of cardiovascular disease in diabetes.

  18. Effects of a chelating resin on metal bioavailability and toxicity to estuarine invertebrates: Divergent results of field and laboratory tests

    Energy Technology Data Exchange (ETDEWEB)

    Wilkie, Emma M., E-mail: ewilkie@bio.mq.edu.a [Department of Environmental Sciences, University of Technology Sydney, Broadway, NSW 2007 (Australia); Ecotoxicology and Environmental Contaminants Section, Department of Environment and Climate Change, Lidcombe, NSW 1825 (Australia); Roach, Anthony C. [Ecotoxicology and Environmental Contaminants Section, Department of Environment and Climate Change, Lidcombe, NSW 1825 (Australia); Micevska, Tina [Centre for Environmental Contaminants Research, CSIRO Land and Water, Menai, NSW 2234 (Australia); Kelaher, Brendan P.; Bishop, Melanie J. [Department of Environmental Sciences, University of Technology Sydney, Broadway, NSW 2007 (Australia)

    2010-05-15

    Benthic invertebrates can uptake metals through diffusion of free ion solutes, or ingestion of sediment-bound forms. This study investigated the efficacy of the metal chelating resin SIR 300{sup TM} in adsorbing porewater metals and isolating pathways of metal exposure. A field experiment (Botany Bay, Sydney, Australia) and a laboratory toxicity test each manipulated the availability of porewater metals within contaminated and uncontaminated sediments. It was predicted that within contaminated sediments, the resin would adsorb porewater metals and reduce toxicity to invertebrates, but in uncontaminated sediments, the resin would not significantly affect these variables. Whereas in the laboratory, the resin produced the predicted results, in the field the resin increased porewater metal concentrations of contaminated sediments for at least 34 days and decreased abundances of four macroinvertebrate groups, and richness in all sediments. These contrasting findings highlight the limits of extrapolating the results of laboratory experiments to the field environment. - Laboratory experiments do not predict the effects on porewater metals or macroinvertebrates of adding a chelating resin to metal-contaminated field sediments.

  19. Effects of a chelating resin on metal bioavailability and toxicity to estuarine invertebrates: Divergent results of field and laboratory tests

    International Nuclear Information System (INIS)

    Benthic invertebrates can uptake metals through diffusion of free ion solutes, or ingestion of sediment-bound forms. This study investigated the efficacy of the metal chelating resin SIR 300TM in adsorbing porewater metals and isolating pathways of metal exposure. A field experiment (Botany Bay, Sydney, Australia) and a laboratory toxicity test each manipulated the availability of porewater metals within contaminated and uncontaminated sediments. It was predicted that within contaminated sediments, the resin would adsorb porewater metals and reduce toxicity to invertebrates, but in uncontaminated sediments, the resin would not significantly affect these variables. Whereas in the laboratory, the resin produced the predicted results, in the field the resin increased porewater metal concentrations of contaminated sediments for at least 34 days and decreased abundances of four macroinvertebrate groups, and richness in all sediments. These contrasting findings highlight the limits of extrapolating the results of laboratory experiments to the field environment. - Laboratory experiments do not predict the effects on porewater metals or macroinvertebrates of adding a chelating resin to metal-contaminated field sediments.

  20. Effects of metal ion chelators on DNA strand breaks and inactivation produced by hydrogen peroxide in Escherichia coli: detection of iron-independent lesions.

    OpenAIRE

    Asad, N R; A.C. Leitão

    1991-01-01

    In order to study the role of metallic ions in the H2O2 inactivation of Escherichia coli cells, H2O2-sensitive mutants were treated with metal ion chelators and then submitted to H2O2 treatment. o-Phenanthroline, dipyridyl, desferrioxamine, and neocuproine were used as metal chelators. Cell sensitivity to H2O2 treatment was not modified by neocuproine, suggesting that copper has a minor role in OH production in E. coli. On the other hand, prior treatment with iron chelators protected the cell...

  1. Immobilized poly-L-histidine for chelation of metal cations and metal oxyanions

    International Nuclear Information System (INIS)

    The biohomopolymer poly-L-histidine (PLHis) was immobilized onto controlled pore glass (CPG) and its metal binding capabilities evaluated through the use of a flow injection-flame atomic absorption system. The metal binding capability of PLHis-CPG was determined through the analysis of the generated breakthrough curves. The polymer likely coordinates cationic metals through the imidazole side chain (pKa∼6) present on each histidine residue with both strong and weak binding sites for Cu2+, Cd2+, Co2+, and Ni2+. Weak to minimal binding was observed for Mn2+, Ca2+, Mg2+, Na+, and Cr3+. The bound metals are quantitatively released from the column with an acid strip. It has also been shown that the protonated imidazole side chain present in acidic solutions is capable of binding metal oxyanions such as chromates, arsenates, and selenites; although oxyanion binding currently exhibits interferences from competing anions in solution, such as sulfate and nitrate. The interference in oxyanion binding is less severe in the presence of chloride, phosphate, and acetate. PLHis-CPG exhibits a capacity of ∼30 μmol Cu2+/g CPG in neutral to basic conditions, and a capacity of ∼70 μmol Cr(VI)/g CPG, ∼4 μmol As(V)/g CPG, and ∼4 μmol Se(IV)/g CPG in acidic conditions

  2. Coordination properties of a metal chelator clioquinol to Zn(2+) studied by static DFT and ab initio molecular dynamics.

    Science.gov (United States)

    Rodríguez-Santiago, Luis; Alí-Torres, Jorge; Vidossich, Pietro; Sodupe, Mariona

    2015-05-28

    Several lines of evidence supporting the role of metal ions in amyloid aggregation, one of the hallmarks of Alzheimer's disease (AD), have turned metal ion chelation into a promising therapeutic treatment. The design of efficient chelating ligands requires proper knowledge of the electronic and molecular structure of the complexes formed, including their hydration properties. Among various potential chelators, clioquinol (5-chloro-7-iodo-8-hydroxyquinoline, CQH) has been evaluated with relative success in in vitro experiments and even in phase 2 clinical trials. Clioquinol interacts with Zn(ii) to lead to a binary metal/ligand 1 : 2 stoichiometric complex in which the phenolic group of CQH is deprotonated, resulting in Zn(CQ)2 neutral complexes, to which additional water molecules may coordinate. In the present work, the coordinative properties of clioquinol in aqueous solution have been analyzed by means of static, minimal cluster based DFT calculations and explicit solvent ab initio molecular dynamics simulations. Results from static calculations accounting for solvent effects by means of polarized continuum models suggest that the preferred metal coordination environment is tetrahedral Zn(CQ)2, whereas ab initio molecular dynamics simulations point to quasi degenerate penta Zn(CQ)2(H2O) and hexa Zn(CQ)2(H2O)2 coordinated complexes. The possible reasons for these discrepant results are discussed. PMID:25939963

  3. Determination of residual fluoroquinolones in honey by liquid chromatography using metal chelate affinity chromatography.

    Science.gov (United States)

    Yatsukawa, Yoh-Ichi; Ito, Hironobu; Matsuda, Takahiro; Nakamura, Munetomo; Watai, Masatoshi; Fujita, Kazuhiro

    2011-01-01

    A new analytical method for the simultaneous determination of seven fluoroquinolones, namely, norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin, orbifloxacin, sarafloxacin, and difloxacin, especially in dark-colored honey, has been developed. Fluoroquinolone antibiotics were extracted from samples with MacIlvaine buffer solution (pH 4.0) containing EDTA disodium salt dihydrate. The extracts were treated with both a polymeric cartridge and a metal chelate affinity column preloaded with ferric ion (Fe3+). LC separation with fluorescence detection was performed at 40 degrees C using an Inertsil ODS-4 analytical column (150 x 4.6 mm, 3 microm). The mobile phase was composed of 20 mM/L citrate buffer solution (pH 3.1)-acetonitrile mixture (70 + 30, v/v) containing 1 mM/L sodium dodecyl sulfate. Lomefloxacin was used as an internal standard. The developed method was validated according to the criteria of European Commission Decision 2002/657/EC. Decision limits and detection capabilities were below 2.9 and 4.4 microg/kg, respectively. PMID:21919363

  4. In vitro growth inhibition of mastitis causing bacteria by phenolics and metal chelators

    Energy Technology Data Exchange (ETDEWEB)

    Chew, B.P.; Tjoelker, L.W.; Tanaka, T.S.

    1985-11-01

    Antimicrobial activities of three phenolic compounds and four metal chelators were tested at 0, 250, 500, and 1000 ppm in vitro against four major mastitis-causing bacteria, Streptococcus agalactiae, Staphylococcus aureus, Klebsiella pnuemoniae, and Escherichia coli. Overall, butylated hydroxyanisole and tert-butylhydroquinone showed the greatest antimicrobial activity. These phenolics were bactericidal at 250 to 500 ppm against all four bacteria tested. The butylated hydroxytoluene was bactericidal against the gram-positive bacteria but was ineffective against the coliforms. At 250 ppm, disodium ethylenediaminetetraacetic acid was bactericidal against the gram-positive bacteria but much less effective against the gram-negatives. However, diethylene-triaminepentaacetic acid was more growth inhibitory than ethylenediaminetetraacetic acid against the gram-negative bacteria and especially against Escherichia coli. All other compounds were generally much less effective or ineffective against all four microorganisms. Therefore, butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, ethylenediaminetetraacetic acid, and diethylenetriaminepentaacetic acid may have practical implications in the prevention or treatment of bovine mastitis.

  5. Separation and determination of trace metal ions using organic chelating reagents

    International Nuclear Information System (INIS)

    The four reagents tested were N,N-dihexylacetamide (DHA), 2,6-diacetylpyridine bis(furoylhydrazone) (H2dapf), 1,3-dimethyl-4-acetyl-2-pyrazolin-5-one (DMAP) and N-methylfurohydroxamic acid (NMFHA). DHA and H2dapf were investigated for their complex formation with uranium, and DMAP and NMFHA were used as chelating agents in high performance liquid chromatography (HPLC). Uranium(VI) is preferentially extracted from nitric acid solutions using DHA in toluene. The extraction characteristics of the U-DHA complex are studied. A 119,000 μgL-1 U solution is analyzed for twenty-six elements. The U is extracted with DHA, and the trace metal ions are then determined by inductively coupled plasma-mass spectrometry. Uranium must be removed from the sample before analysis to prevent ionization suppression. H2dapf is synthesized and characterized. Studies of the complexation of metal ions with H2dapf is described. U(VI) forms a stable complex with H2dapf, and a procedure for selectively determining trace U by spectrophotometry is presented. DMAP complexes of Cu(II), Fe(III), Ga(III), Th(IV), U(VI), V(V), and Zr(IV) are separated using reversed phase HPLC. NMFHA complex of Al(III), Fe(III), Hf(IV), Nb(V), Sb(III), and Zr(IV) are separated using reversed phase HPLC. NMFHA is also used to separate uranium(VI) from trace lanthanide ions. 266 refs., 46 figs., 24 tabs

  6. Optimization of fuel cell membrane electrode assemblies for transition metal ion-chelating ordered mesoporous carbon cathode catalysts

    OpenAIRE

    Johanna K. Dombrovskis; Cathrin Prestel; Anders E. C. Palmqvist

    2014-01-01

    Transition metal ion-chelating ordered mesoporous carbon (TM-OMC) materials were recently shown to be efficient polymer electrolyte membrane fuel cell (PEMFC) catalysts. The structure and properties of these catalysts are largely different from conventional catalyst materials, thus rendering membrane electrode assembly (MEA) preparation parameters developed for conventional catalysts not useful for applications of TM-OMC catalysts. This necessitates development of a methodology to incorporate...

  7. Chelating resin from functionalization of chitosan with complexing agent 8-hydroxyquinoline: application for metal ions on line preconcentration system

    International Nuclear Information System (INIS)

    This study describes the functionalization of biopolymer chitosan, using the complexing agent 8-hydroxyquinoline (oxine) by reaction of diazotization. The chelating resin was characterized by degree of deacetylation, infrared, Raman spectroscopy. The efficiency of the chelating resin and accuracy of the proposed method was evaluated by the metal ion recovery technique in the analysis of potable water, lake water, seawater and a certified sample of oyster tissue. The metal ions Cd(II) and Cu(II) in the samples were previously enriched in a minicolumn and flow injection flame atomic absorption spectrometry (FI-FAAS) determined the concentrations of the analytes. The chelating resin exhibited high selectivity for Cd(II) at pH 7 and for Cu(II) at pH 10. The eluent concentration was tested by the use of HNO3 in concentrations of 0.1-3 mol l-1 maximum response was obtained at 0.5 mol l-1 for Cd(II) and Cu(II), with R.S.D. values of 0.4%. The analytes gave relative standard deviations (R.S.D.) of 1.5 and 0.7% for solutions of Cd(II) and Cu(II), respectively (n = 7) containing 20 μg l-1 of the metal ions, defining a high reproducibility. The limits of detection (LOD) were 0.1 μg l-1 for Cd(II) and 0.4 μg l-1 for Cu(II). The analytical properties of merit were obtained using the parameters previously optimized with preconcentration time of 90 s. The chelating resin showed chemical stability within a wide range of pH and the efficiency was not altered for the preconcentration of the metal ions during all the experiments

  8. Functionalization of Cellulose Nanocrystals with PEG-Metal-Chelating Diblock Copolymers via Controlled Conjugation in Aqueous Medium

    Science.gov (United States)

    Guo, Melinda

    The surface of cellulose nanocrystals (CNCs) was successfully functionalized with metal chelating diblock copolymers via HyNic-4FB conjugation. Two types of PEG-metal-chelating block polymers with hydrazinonicotinate acetone hydrazine (HyNic) end groups were synthesized: mPEG-PGlu(DTPA) 18-HyNic and mPEG-PGlu(DTPA)25-HyNic. These two polymers both had a methoxy PEG (M ˜ 2000 Da) block that differed in the mean degree of polymerization of the metal-chelating block. They were characterized by 1H NMR spectroscopy and gel-permeation chromatography (GPC). 4-Formylbenzamide (4FB) groups were introduced onto the surface of CNCs and quantified through their reaction with 2-hydrazinopyridine. The polymers were grafted onto the surface of CNCs via bis-aryl hydrazone bond formation, and the kinetics of this reaction was explored by UV/Vis spectroscopy. The CNCs were also labeled with rhodamine and Alexa FluorRTM 488 dyes. Students in our collaborator's group in Pharmacy are examining applications of these materials as radiotherapeutic agents for cancer treatment.

  9. Excited state evolution towards ligand loss and ligand chelation at group 6 metal carbonyl centres.

    Science.gov (United States)

    Manton, Jennifer C; Amirjalayer, Saeed; Coleman, Anthony C; McMahon, Suzanne; Harvey, Emma C; Greetham, Gregory M; Clark, Ian P; Buma, Wybren Jan; Woutersen, Sander; Pryce, Mary T; Long, Conor

    2014-12-21

    the reactive state responsible for the arrested CO-loss has significant metal-to-carbonyl charge-transfer character. The CO-loss product (η(6)-allylbenzene)Cr(CO)2 formed following irradiation of (η(6)-allylbenzene)Cr(CO)3 reacts further with the pendent alkenyl group to form the chelate product (η(6),η(2)-allylbenzene)Cr(CO)2. PMID:25093429

  10. Effect of Metal Ions, Chelating Agent and SH-Reagents on Radish (Raphanus sativus L.) Root β-Amylase

    OpenAIRE

    Sarowar Jahan M.G.; M. Shaela Pervin; M. Shariar Shovon; DEV SHARMA S.C.; Narayan Roy; M. Habibur Rahman

    2012-01-01

    Metal ions play vital roles in enzymes. They may also show sensitivity to various sulfhydryl reagents and chelating reagents. Effect of some metal ions, EDTA and sulfhydryl reagents on the activity of partially purified β-amylase of radish root were studied. Amylolytic activity of purified enzyme was increased substantially in the presence of Ca2+, Mg2+, and Zn2+. Some other divalent cations Cu2+, Pb2+, Sn2+, and Hg2+ almost completely ceased the enzyme activity. Cobalt (II), Manganese (II), ...

  11. N-Acetyl-Cysteine as Effective and Safe Chelating Agent in Metal-on-Metal Hip-Implanted Patients: Two Cases

    Science.gov (United States)

    Lonati, Davide; Ragghianti, Benedetta; Ronchi, Anna; Vecchio, Sarah; Locatelli, Carlo Alessandro

    2016-01-01

    Systemic toxicity associated with cobalt (Co) and chromium (Cr) containing metal hip alloy may result in neuropathy, cardiomyopathy, and hypothyroidism. However clinical management concerning chelating therapy is still debated in literature. Here are described two metal-on-metal hip-implanted patients in which N-acetyl-cysteine decreased elevated blood metal levels. A 67-year-old male who underwent Co/Cr hip implant in September 2009 referred to our Poison Control Centre for persisting elevated Co/Cr blood levels (from March 2012 to November 2014). After receiving oral high-dose N-acetyl-cysteine, Co/Cr blood concentrations dropped by 86% and 87% of the prechelation levels, respectively, and persisted at these latter concentrations during the following 6 months of follow-up. An 81-year-old female who underwent Co/Cr hip implant in January 2007 referred to our Centre for detection of high Co and Cr blood levels in June 2012. No hip revision was indicated. After a therapy with oral high-dose N-acetyl-cysteine Co/Cr blood concentrations decreased of 45% and 24% of the prechelation levels. Chelating agents reported in hip-implanted patients (EDTA, DMPS, and BAL) are described in few cases. N-acetyl-cysteine may provide chelating sites for metals and in our cases reduced Co and Cr blood levels and resulted well tolerable. PMID:27148463

  12. Synthetic, structural, thermal and electrical properties of some transition metal polymeric chelates of bis(mercaptoacetamido)diaminobutane

    International Nuclear Information System (INIS)

    Polymeric chelates of bis(mercaptoacetamido)-1,4-diaminobutane (BMADB) with manganese(II), cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) ions have been synthesized and characterized by elemental analysis, magnetic moment, infrared, electronic spectra and thermal analysis. In the present investigation the ligand BMADB exhibits bis-bidentate character and coordinates symmetrically with metal through nitrogen of amino and sulfur mercapto groups. The thermogravimetric studies indicate a two stage decomposition and the presence of water molecules. Thermal data have been analysed by Freeman-Carroll and Sharp-Wentworth methods and various kinetic and thermodynamic parameters have also be evaluated. Comparable values of parameters indicate common decomposition reaction mode of all chelates. Their d.c. electrical conductivity in pellet form over a wide range of temperatures have also been studied. (author)

  13. Controlled hydrothermal growth of ZnO nanostructures by sequestering the Zn metal ions with the chelating agent EDTA

    Science.gov (United States)

    Ram, S. D. Gopal; Ravi, G.; Manikandan, MR.; Mahalingam, T.; Anbu Kulandainathan, M.

    2011-10-01

    In the present work, a controlled growth of ZnO nanostructures by manipulating Zn metal ion concentration by the chelating action of ethylene diaminetetra acetic acid in hydrothermal method is studied. EDTA produces metal-chelate complex by the formation of bidentate ligand with Zn 2+ in the solution and diminishes the reactivity of Zn metal cations. Concentration of EDTA in the mother solution was varied in different ranges like 3, 5 and 10 mM while retaining the zinc metal salt and the NaOH concentration the same. Three different morphologies of wurtzite structured ZnO nanostructures such as nanorods-bunch, separate/discrete uniformly sized hexagonal nanorods and tapered flower petals like shapes are achieved by 3, 5 and 10 mM strengths of EDTA, respectively. The medium concentration 5 mM of EDTA is found to have moderate control over producing ZnO nanostructures of uniform diameter and a high aspect (length to diameter) ratio. An array of vertically aligned free standing ZnO nanorods with uniform spacing is successfully achieved by the addition of 5 mM of EDTA in the mother solution and the same is studied for its fluorescence property at an excitation of 325 nm and it has exhibited a characteristic UV emission of ZnO around 383 nm.

  14. A new synthesis, characterization and application chelating resin for determination of some trace metals in honey samples by FAAS.

    Science.gov (United States)

    Daşbaşı, Teslima; Saçmacı, Şerife; Çankaya, Nevin; Soykan, Cengiz

    2016-07-15

    In this study, we developed a simple and rapid solid phase extraction (SPE) method for the separation/preconcentration and determination of some trace metals by flame atomic absorption spectrometry (FAAS). A new chelating resin, poly [2-(4-methoxyphenylamino)-2-oxoethyl methacrylate-co-divinylbenzene-co-2-acrylamido-2-methyl-1-propanesulfonic acid] (MPAEMA-co-DVB-co-AMPS), was synthesized and characterized. This chelating resin was used as a new adsorbent material for determination of Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Mn(II), Pb(II), and Zn(II) ions. The parameters influential on the determination of this trace metals were examined. Under the optimum conditions, the detection limits (DL) of the method for trace metals were found to be (3s) in the range of 0.9-2.2 μg L(-1) (n=21), the preconcentration factor was calculated as 200 and the relative standard deviation was obtained achieved as ⩽2% for n=11. The method was performed for the determination of trace metals in some honey samples and standard reference materials. PMID:26948616

  15. High-throughput assay comparison and standardization for metal chelating capacity screening: A proposal and application.

    Science.gov (United States)

    Santos, Jânio Sousa; Alvarenga Brizola, Vitor Rafael; Granato, Daniel

    2017-01-01

    Aiming to standardize the experimental protocols to assess the ability to chelate Fe(2+) and Cu(2+) using 96-well microplates, we analyzed Brazilian coffees (n=20) as a study-case in relation to their antioxidant activity using conventional methods (DPPH and FRAP assays) and correlated the results with the total phenolic content (TPC) using bivariate and multivariate statistical approaches. Complementarily, we assessed the repeatability, reproducibility, recovery, and linearity of both methods. Data showed that the proposed assays presented a good repeatability and reproducibility (assays, respectively. Both methods were linear in the range of 0-100mg EDTA equivalents/L. Cu(2+)-chelating ability was significantly correlated to FRAP, DPPH, and TPC, while sparse (passays can be used to assess the ability of plant-based extracts to chelate Fe(2+) and Cu(2+)in vitro. PMID:27507505

  16. A bis(3-hydroxy-4-pyridinone)-EDTA derivative as a strong chelator for M3+ hard metal ions: complexation ability and selectivity.

    Science.gov (United States)

    Gama, Sofia; Dron, Paul; Chaves, Silvia; Farkas, Etelka; Santos, M Amélia

    2009-08-21

    The study of chelating compounds is very important to solve problems related to human metal overload. 3-Hydroxy-3-pyridinones (HP), namely deferiprone, have been clinically used for chelating therapy of Fe and Al over the last decade. A multi-disciplinary search for alternative molecules led us to develop poly-(3-hydroxy-4-pyridinones) to increase metal chelation efficacy. We present herein a complexation study of a new bis-(3-hydroxy-4-pyridinone)-EDTA derivative with a set of M(3+) hard metal ions (M = Fe, Al, Ga), as well as Zn(2+), a biologically relevant metal ion. Thus a systematic aqueous solution equilibrium study was performed using potentiometric and spectroscopic techniques (UV-Vis, NMR methods). These set of results enables the establishment of specific models as well as the determination of thermodynamic stability constants and coordination modes of the metal complexes. The results indicate that this ligand has a higher affinity for chelating to these hard metal ions than deferiprone, and that the coordination occurs mostly through the HP moieties. Furthermore, it was also found that this ligand has a higher selectivity for chelating to M(3+) hard metal ions (M = Fe, Al, Ga) than Zn(2+). PMID:20449110

  17. Modern Chemistry Techniques Applied to Metal Behavior and Chelation in Medical and Environmental Systems ? Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, M; Andresen, B; Burastero, S R; Chiarappa-Zucca, M L; Chinn, S C; Coronado, P R; Gash, A E; Perkins, J; Sawvel, A M; Szechenyi, S C

    2005-02-03

    This report details the research and findings generated over the course of a 3-year research project funded by Lawrence Livermore National Laboratory (LLNL) Laboratory Directed Research and Development (LDRD). Originally tasked with studying beryllium chemistry and chelation for the treatment of Chronic Beryllium Disease and environmental remediation of beryllium-contaminated environments, this work has yielded results in beryllium and uranium solubility and speciation associated with toxicology; specific and effective chelation agents for beryllium, capable of lowering beryllium tissue burden and increasing urinary excretion in mice, and dissolution of beryllium contamination at LLNL Site 300; {sup 9}Be NMR studies previously unstudied at LLNL; secondary ionization mass spec (SIMS) imaging of beryllium in spleen and lung tissue; beryllium interactions with aerogel/GAC material for environmental cleanup. The results show that chelator development using modern chemical techniques such as chemical thermodynamic modeling, was successful in identifying and utilizing tried and tested beryllium chelators for use in medical and environmental scenarios. Additionally, a study of uranium speciation in simulated biological fluids identified uranium species present in urine, gastric juice, pancreatic fluid, airway surface fluid, simulated lung fluid, bile, saliva, plasma, interstitial fluid and intracellular fluid.

  18. Structure-Activity Relationships and Identification of Optmized CC-Chemokine Receptor CCR1, 5, and 8 Metal-Ion Chelators

    DEFF Research Database (Denmark)

    Chalikiopoulos, Alexander; Thiele, Stefanie; Malmgaard-Clausen, Mikkel;

    2013-01-01

    Chemokine receptors are involved in trafficking of leukocytes and represent targets for autoimmune conditions, inflammatory diseases, viral infections, and cancer. We recently published CCR1, CCR8, and CCR5 agonists and positive modulators based on a three metal-ion chelator series: 2,2'-bipyridine...... bipyridine (23). The structure-activity relationships contribute to small-molecule drug development, and the novel chelators constitute valuable tools for studies of structural mechanisms for chemokine receptor activation....

  19. Chelating polymeric membranes

    KAUST Repository

    Peinemann, Klaus-Viktor

    2015-01-22

    The present application offers a solution to the current problems associated with recovery and recycling of precious metals from scrap material, discard articles, and other items comprising one or more precious metals. The solution is premised on a microporous chelating polymeric membrane. Embodiments include, but are not limited to, microporous chelating polymeric membranes, device comprising the membranes, and methods of using and making the same.

  20. Incorporation of transition metals into Mg-Al layered double hydroxides: Coprecipitation of cations vs. their pre-complexation with an anionic chelator

    International Nuclear Information System (INIS)

    A comparative study on two different methods for preparing Mg-Al layered double hydroxides (LDH) containing various divalent transition metals M (M=Co, Ni, Cu) has been carried out. The first (conventional) method involved coprecipitation of divalent metals M(II) with Mg(II) and Al(III) cations using carbonate under basic conditions. The second approach was based on the ability of transition metals to form stable anionic chelates with edta4- (edta4-=ethylenediaminetetraacetate) that were synthesized and further introduced into LDH by coprecipitation with Mg and Al. The synthesized LDHs were characterized by X-ray diffraction (XRD) and X-ray fluorescence (XRF) methods, thermogravimetry with mass-selective detection of decomposition products (TG-MSD), Fourier transform infrared (FTIR) and Raman spectroscopy techniques. The results obtained were discussed in terms of efficiency of transition metal incorporation into the LDH structure, thermal stability of materials and the ability of metal chelates to intercalate the interlayer space of Mg-Al LDH. Vibrational spectroscopy studies confirmed that the integrity of the metal chelates was preserved upon incorporation into the LDH. - Graphical abstract: Two ways for introducing transition metals M(II) into Mg-Al layered double hydroxides (MY2- denotes the edta chelate of transition metal M(II))

  1. Bioavailability assessment of metals chelated as proteinates using the Ussing Chamber Model

    OpenAIRE

    Piva, G.; G. Cavanna; G. Casadei; A. Piva

    2011-01-01

    Preparation of proteinates by hydrolysis of organic matter produces a blend of different proteins, and may likely result in the chelation of trace elements. Often this process results in an increased bioavailability of minerals, leading to a higher absorption rate than inorganic salts (Cao et al., 2000; Uchida et al., 2001; Bailey et al., 2001; Guo et al., 2001). Usually trace elements uptake takes place along the small intestine, mainly jejunum (Tapia et al., 1996; Arredondo et al., 2000), e...

  2. The interactive effects of chelator, fertilizer, and rhizobacteria for enhancing phytoremediation of heavy metal contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H.; Cutright, T.J. [Dept. of Civil Engineering, Univ. of Akron, Akron, OH (United States)

    2002-07-01

    The role of chelator, fertilizer, and enriched rhizobacteria in facilitating Cd, Cr, and Ni accumulation by Helianthus annuus was studied. It was found that by adding a synthetic chelator, EDTA, the shoot concentrations of Cd and Ni were significantly increased from 34.2 mg kg{sup -1} and 14.5 mg kg{sup -1} to 115 mg kg{sup -1} and 117 mg kg{sup -1}, respectively. However, the total biomass of plants was drastically decreased by 50 to 60%. Compared with this treatment, inoculating enriched rhizobacteria to plants grown under similar conditions maintained the surged shoot concentrations of Cd and Ni while increasing the plants biomass by more than 1.6-fold. It was also found that introducing a commercial fertilizer, Hydro-Gro trademark, to plants significantly increased the Ni accumulation by 3-fold and the plant biomass by 1.43-fold. These results suggest that combing fertilizers, chelators and/or rhizobacteria might provide a more effective approach for enhancing phytoremediation. (orig.)

  3. Chelatization of Metals Ion (Cu2+, Cd2+ and Cr3+) with ProcessYield of Humic Acid from Peat Soil

    International Nuclear Information System (INIS)

    The chelation of metals ion (Cu2+, Cd2+ and Cr3+) with processyields of humic acid from peat soil has been done. The chelatizationcalculation was carried out using a mathematical model of the metals ionneutralization to the humic acid functional group. The model has superioritydue to the introduction of the humic acid concentration conditional and theloading capacity. Chelation is expected to obtain the constant experimentthat agrees with environmental conditional were the chelatization to takeplaces. By the tree neck flask of bath reactor, 250 ml volume at thetemperature of 25 oC chelation have been done and the AAS was used toanalyzes the yield. By mathematical calculate was obviously proved that thechelation constants was not influenced by pH, ionic strength and origin peatsoils. As log β, chelation constants of Cu2+, Cd2+ and Cr3+ were4.67 (± 0.02); 5.98 (± 0.02) and 6.09 (± 0.01) for humic acid fromSumatra I (Silaut III) and 4.68 (± 0.01); 5.97 (± 0.02) and 6.09 (±0.02) for Sumatra II (Silaut IV). While chelation constant Cu2+, Cd2+ andCr3+ from Kalimantan were 4.66 (± 0.03); 5.99 (± 0.01); 6.08 (±0.02). (author)

  4. Alarming use of chelation therapy

    OpenAIRE

    Crisponi, Guido; Nurchi, Valeria Marina; Lachowicz, Joanna I.; Crespo-Alonso, Miriam; Zoroddu, Maria Antonietta; Peana, Massimiliano Francesco

    2014-01-01

    Chelation therapy is a consolidated medical procedure used primarily to hinder the effects of toxic metal ions on human tissues. Its application spans a broad spectrum of disorders, ranging from acute metal intoxication to genetic metal-overload. The use of chelating agents is compromised by a number of serious side effects, mainly attributable to perturbed equilibrium of essential metal ion homeostasis and dislocation of complexed metal ions to dangerous body sites. For this reason, chelatio...

  5. Metal chelation, radical scavenging and inhibition of Aβ₄₂ fibrillation by food constituents in relation to Alzheimer's disease.

    Science.gov (United States)

    Chan, Stephen; Kantham, Srinivas; Rao, Venkatesan M; Palanivelu, Manoj Kumar; Pham, Hoang L; Shaw, P Nicholas; McGeary, Ross P; Ross, Benjamin P

    2016-05-15

    Various food constituents have been proposed as disease-modifying agents for Alzheimer's disease (AD), due to epidemiological evidence of their beneficial effects, and for their ability to ameliorate factors linked to AD pathogenesis, namely by: chelating iron, copper and zinc; scavenging reactive oxygen species; and suppressing the fibrillation of amyloid-beta peptide (Aβ). In this study, nine different food constituents (l-ascorbic acid, caffeic acid, caffeine, curcumin, (-)-epigallocatechin gallate (EGCG), gallic acid, propyl gallate, resveratrol, and α-tocopherol) were investigated for their effects on the above factors, using metal chelation assays, antioxidant assays, and assays of Aβ42 fibrillation. An assay method was developed using 5-Br-PAPS to examine the complexation of Zn(II) and Cu(II). EGCG, gallic acid, and curcumin were identified as a multifunctional compounds, however their poor brain uptake might limit their therapeutic effects. The antioxidants l-ascorbic acid and α-tocopherol, with better brain uptake, deserve further investigation for specifically addressing oxidative stress within the AD brain. PMID:26775960

  6. Optimization of fuel cell membrane electrode assemblies for transition metal ion-chelating ordered mesoporous carbon cathode catalysts

    Directory of Open Access Journals (Sweden)

    Johanna K. Dombrovskis

    2014-12-01

    Full Text Available Transition metal ion-chelating ordered mesoporous carbon (TM-OMC materials were recently shown to be efficient polymer electrolyte membrane fuel cell (PEMFC catalysts. The structure and properties of these catalysts are largely different from conventional catalyst materials, thus rendering membrane electrode assembly (MEA preparation parameters developed for conventional catalysts not useful for applications of TM-OMC catalysts. This necessitates development of a methodology to incorporate TM-OMC catalysts in the MEA. Here, an efficient method for MEA preparation using TM-OMC catalyst materials for PEMFC is developed including effects of catalyst/ionomer loading and catalyst/ionomer-mixing and application procedures. An optimized protocol for MEA preparation using TM-OMC catalysts is described.

  7. Optimization of fuel cell membrane electrode assemblies for transition metal ion-chelating ordered mesoporous carbon cathode catalysts a

    Science.gov (United States)

    Dombrovskis, Johanna K.; Prestel, Cathrin; Palmqvist, Anders E. C.

    2014-12-01

    Transition metal ion-chelating ordered mesoporous carbon (TM-OMC) materials were recently shown to be efficient polymer electrolyte membrane fuel cell (PEMFC) catalysts. The structure and properties of these catalysts are largely different from conventional catalyst materials, thus rendering membrane electrode assembly (MEA) preparation parameters developed for conventional catalysts not useful for applications of TM-OMC catalysts. This necessitates development of a methodology to incorporate TM-OMC catalysts in the MEA. Here, an efficient method for MEA preparation using TM-OMC catalyst materials for PEMFC is developed including effects of catalyst/ionomer loading and catalyst/ionomer-mixing and application procedures. An optimized protocol for MEA preparation using TM-OMC catalysts is described.

  8. Synthesis of gold nanoparticles stabilised by metal-chelator and the controlled formation of close-packed aggregates by them

    Indian Academy of Sciences (India)

    Santanu Bhattacharya; Aasheesh Srivastava

    2003-10-01

    Nanoparticles have properties that can be fine-tuned by their size as well as shape. Hence, there is significant current interest in preparing nano-materials of small size dispersity and to arrange them in close-packed aggregates. This manuscript describes ways of synthesising gold nanoparticles using a metal-chelator derivative 1, as stabiliser. Controlled synthesis conditions lead to formation of nanoparticles thereby indicating the ability of 1 to act as efficient stabiliser. The nanoparticles formed were characterised by transmission electron microscopy and UV-Vis spectroscopy. TEM analysis showed the formation of dense aggregates of nanoparticles. This can be ascribed to the inter-particle hydrogen bonding possible by the carboxylic acid moiety of 1 that leads to aggregation. The aggregation can be controlled by the pH of the solution employed for dispersing the particles.

  9. Use of non-hyperaccumulator plant species for the phytoextraction of heavy metals using chelating agents

    OpenAIRE

    Lucas Anjos Souza; Fernando Angelo Piotto; Roberta Corrêa Nogueirol; Ricardo Antunes Azevedo

    2013-01-01

    Soil contamination by heavy metals is a challenge faced by many countries, and engineering technologies to solve this problem are expensive and can cause negative impacts on the environment. One way to minimise the levels of heavy metals in the soil is to use plants that can absorb and accumulate heavy metals into harvestable parts, a process called phytoextraction. Typical plant species used in research involving phytoextraction are heavy metal hyperaccumulators, but plants from this group a...

  10. Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO{sub 2}. Annual progress report, September 15, 1996--September 14, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Brennecke, J.F.; Stadtherr, M.A.; Chateauneuf, J.E.

    1997-01-01

    'This progress report contains (1) a statement of the objectives of the overall project, (2) a discussion of the results obtained during the first year of the three year grant period, (3) a summary, (4) a description of the future work that will be pursued during the next year, and (5) accounting information. This is followed by the literature cited and the pertinent tables and figures. The overall objectives of this project are to gain a fundamental understanding of the solubility and stability of metal chelates in supercritical CO{sub 2}. Extraction with CO{sub 2} is a excellent way to remove organic compounds from soils, sludges and aqueous solutions and recent research has demonstrated that together with chelating agents it is a viable way to remove metals, as well. The authors seek to gain fundamental knowledge that is vital to computing phase behavior, and modeling and designing processes using CO{sub 2} to separate organics and metal compounds from DOE mixed wastes. The overall program is a comprehensive one to measure local solvation of metal chelates and to determine metal chelate stability in supercritical fluid mixtures using UV-vis and FTIR spectroscopy. The spectroscopic studies provide information on the solution microstructure, which they are using in concert with their own and published solubility data to evaluate and develop thermodynamic models of the solubility behavior. Finally, they are implementing a more reliable computational technique, based on interval mathematics, to compute the phase equilibria using the thermodynamic modeIs. This fundamental information about metal chelate stability and solubility in supercritical CO{sub 2} is important in the design of processes using CO{sub 2} to extract components from mixed wastes and in determining the optimum operating conditions.'

  11. Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO2. Annual progress report, September 15, 1996 - September 14, 1997

    International Nuclear Information System (INIS)

    'This progress report contains (1) a statement of the objectives of the overall project, (2) a discussion of the results obtained during the first year of the three year grant period, (3) a summary, (4) a description of the future work that will be pursued during the next year, and (5) accounting information. This is followed by the literature cited and the pertinent tables and figures. The overall objectives of this project are to gain a fundamental understanding of the solubility and stability of metal chelates in supercritical CO2. Extraction with CO2 is a excellent way to remove organic compounds from soils, sludges and aqueous solutions and recent research has demonstrated that together with chelating agents it is a viable way to remove metals, as well. The authors seek to gain fundamental knowledge that is vital to computing phase behavior, and modeling and designing processes using CO2 to separate organics and metal compounds from DOE mixed wastes. The overall program is a comprehensive one to measure local solvation of metal chelates and to determine metal chelate stability in supercritical fluid mixtures using UV-vis and FTIR spectroscopy. The spectroscopic studies provide information on the solution microstructure, which they are using in concert with their own and published solubility data to evaluate and develop thermodynamic models of the solubility behavior. Finally, they are implementing a more reliable computational technique, based on interval mathematics, to compute the phase equilibria using the thermodynamic models. This fundamental information about metal chelate stability and solubility in supercritical CO2 is important in the design of processes using CO2 to extract components from mixed wastes and in determining the optimum operating conditions.'

  12. Regeneration of Three-Way Automobile Catalysts using Biodegradable Metal Chelating Agent – S, S-Ethylenediamine Disuccinic Acid (S, S-EDDS)

    Science.gov (United States)

    Regeneration of the activity of three-way catalytic converters (TWCs) was tested for the first time using a biodegradable metal chelating agent (S, S. Ethylenediamine disuccinic acid (S, S-EDDS). The efficiency of this novel environmentally friendly solvent in removing various c...

  13. Sequential application of chelating agents and innovative surfactants for the enhanced electroremediation of real sediments from toxic metals and PAHs.

    Science.gov (United States)

    Hahladakis, John N; Lekkas, Nikolaos; Smponias, Andreas; Gidarakos, Evangelos

    2014-06-01

    This study focused on the sequential application of a chelating agent (citric acid) followed by a surfactant in the simultaneous electroremediation of real contaminated sediments from toxic metals and Polycyclic Aromatic Hydrocarbons (PAHs). Furthermore, the efficiency evaluation of two innovative non-ionic surfactants, commercially known as Poloxamer 407 and Nonidet P40, was investigated. The results indicated a removal efficacy of approximately 43% and 48% for the summation of PAHs (SUM PAHs), respectively for the aforementioned surfactants, much better than the one obtained by the use of Tween 80 (nearly 21%). Individual PAHs (e.g. fluorene) were removed in percentages that reached almost 84% and 92% in the respective electrokinetic experiments when these new surfactants were introduced. In addition, the combined-enhanced sequential electrokinetic treatment with citric acid improved dramatically the removal of Zn and As, compared to the unenhanced run, but did not favor the other toxic metals examined. Since no improvement in metal removal percentages occurred when Tween 80 was used, significant contribution to this matter should also be attributed to the solubilization capacity of these innovative, in electrokinetic remediation, non-ionic surfactants. PMID:24321329

  14. The Metal Cation Chelating Capacity of Astaxanthin. Does This Have Any Influence on Antiradical Activity?

    Directory of Open Access Journals (Sweden)

    Ana Martínez

    2012-01-01

    Full Text Available In this Density Functional Theory study, it became apparent that astaxanthin (ASTA may form metal ion complexes with metal cations such as Ca+2, Cu+2, Pb+2, Zn+2, Cd+2 and Hg+2. The presence of metal cations induces changes in the maximum absorption bands which are red shifted in all cases. Therefore, in the case of compounds where metal ions are interacting with ASTA, they are redder in color. Moreover, the antiradical capacity of some ASTA-metal cationic complexes was studied by assessing their vertical ionization energy and vertical electron affinity, reaching the conclusion that metal complexes are slightly better electron donors and better electron acceptors than ASTA.

  15. Computer simulation of metal ion equilibria in biofluids. IV. Plutonium speciation in human blood plasma and chelation therapy using polyaminopolycarboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Duffield, J.R.; May, P.M.; Williams, D.R.

    1984-03-01

    An investigation by computer simulation into the nature of Pu(IV) binding to low-molecular ligands in human blood plasma is described. Particular consideration is given to the interactions of various chelating agents which have been or might be used for treating plutonium intoxication. Formation constants of EDTA and DTPA with Cu(II), Mg(II), Mn(II), Zn(II), and Cd(II) have been measured under biologic conditions of temperature and background electrolyte. The relative ability of these and other chelating agents to cause excretion of plutonium and the concomitant loss of certain essential trace metals has thus been assessed.

  16. Discovery of Metal Ions Chelator Quercetin Derivatives with Potent Anti-HCV Activities

    Directory of Open Access Journals (Sweden)

    Dongwei Zhong

    2015-04-01

    Full Text Available Analogues or isosteres of α,γ-diketoacid (DKA 1a show potent inhibition of hepatitis C virus (HCV NS5B polymerase through chelation of the two magnesium ions at the active site. The anti-HCV activity of the flavonoid quercetin (2 could partly be attributed to it being a structural mimic of DKAs. In order to delineate the structural features required for the inhibitory effect and improve the anti-HCV potency, two novel types of quercetin analogues, 7-O-arylmethylquercetins and quercetin-3-O-benzoic acid esters, were designed, synthesized and evaluated for their anti-HCV properties in cell-based assays. Among the 38 newly synthesized compounds, 7-O-substituted derivative 3i and 3-O-substituted derivative 4f were found to be the most active in the corresponding series (EC50 = 3.8 μM and 9.0 μΜ, respectively. Docking studies suggested that the quercetin analogues are capable of establishing key coordination with the two magnesium ions as well as interactions with residues at the active site of HCV NS5B.

  17. Development of new metal chelates for animal nutrition and of analytical methods for their quantitative determination and quality control

    OpenAIRE

    Beltrami, Diego

    2009-01-01

    The growing interest for mineral integration to increase mineral bioavalability brought researchers to re-examine accurately the impact that complexes and chelates can have for food industry. In fact, the so-called organic or chelate mineral forms, in particular those associated with amino acids, peptides or other organic molecules, afforded encouraging results in different in vivo tests on animals of economic interest fed with fodder containing minerals in the form of chelates. Moreover, it ...

  18. Thermodynamic parameters and stabilities of some rare-earth metal ion chelates of alpha-valine

    International Nuclear Information System (INIS)

    Solution equilibrium for some rare-earth metal ions with valine have been studied potentiometrically in aqueous medium at temperature from 25 to 55 deg. C and ionic strength from 0.1 to 1.0 mol dm/sup -3/NaClO/sub 4/. The thermodynamic parameters delta H, delta S, delta G for the formation process were evaluated in terms of temperature, ionic strength and nature of metal ion present. The stability of the complexes was found to: La(III)< Nd(III)< Gd(III)< Eu(III)Yb(III)< Lu(III). (author)

  19. Conversion of agonist site to metal-ion chelator site in the β2-adrenergic receptor

    OpenAIRE

    Elling, Christian E.; Thirstrup, Kenneth; Holst, Birgitte; Thue W. Schwartz

    1999-01-01

    Previously metal-ion sites have been used as structural and functional probes in seven transmembrane receptors (7TM), but as yet all the engineered sites have been inactivating. Based on presumed agonist interaction points in transmembrane III (TM-III) and -VII of the β2-adrenergic receptor, in this paper we construct an activating metal-ion site between the amine-binding Asp-113 in TM-III—or a His residue introduced at this position—and a Cys residue substituted for Asn-312 in TM-VII. No inc...

  20. Conversion of agonist site to metal-ion chelator site in the beta(2)-adrenergic receptor

    DEFF Research Database (Denmark)

    Elling, C E; Thirstrup, K; Holst, Birgitte;

    1999-01-01

    Previously metal-ion sites have been used as structural and functional probes in seven transmembrane receptors (7TM), but as yet all the engineered sites have been inactivating. Based on presumed agonist interaction points in transmembrane III (TM-III) and -VII of the beta(2)-adrenergic receptor,...

  1. Single-step coacervate-mediated preconcentration of metals and metal-chelates in supramolecular vesicular surfactant assemblies and determination by flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    The use of ionic surfactant supramolecular aggregates is described, as means for accomplishing the concentration of analytes with different polarities using the same extraction pattern. The proposed method is based on the phase separation of an anionic surfactant through the formation of perplexed lamellar phases, allowing for the extraction of hydrated metal cations by complexation and metal-chelates by hydrophobic interactions. The data suggest that both extraction and phase separation are controlled by the presence of ionic surfactant as a function of the degree of phase divergence from the lamellar to bilayer phase. This again is determined by the composition of the phase-forming parameters, these are the surfactant concentration, the kind and amount of metallic counterparts and ionic strength. On the basis of these findings, the proposed method was successfully applied to the determination of metal species in natural waters. The limits of detection were easily brought down to the low microgram per liter levels by simply preconcentrating 10 mL of sample volume in the presence of at least 0.45% (w/v) of anionic surfactant. The method provided extraction recoveries higher than 94.0% with standard deviations well below 7.0%

  2. SYNTHESIS, CHARACTERIZATION AND CHELATING PROPERTIES OF PYRIMIDINE-QUINOLINE COMBINED MOLECULE WITH TRANSITION METALS

    Directory of Open Access Journals (Sweden)

    Purvesh J. Shah

    2013-09-01

    Full Text Available The treatment of ethyl-6-methyl-2-oxo-4-phenyl-1,2-dihydropyrimidone-5-carboxylate with 5-amino-8-hydroxyquinoline afford a N-(4-hydroxyquinolin-5-yl-6-methyl-2-oxo-4-phenyl-1,2-dihydro pyrimidine-5-carboxamide(PDHQ. The transition metal complexes of Cu2+,Co2+ ,Ni2+, Mn2+ and Zn2+ of PDHQ have been prepared and characterized by elemental analysis, spectral studies, magnetic moment determination, molar conductivity measurement and microbicidal activity.

  3. Orally Bioavailable Metal Chelators and Radical Scavengers: Multifunctional Antioxidants for the Coadjutant Treatment of Neurodegenerative Diseases.

    Science.gov (United States)

    Kawada, Hiroyoshi; Kador, Peter F

    2015-11-25

    Neurodegenerative diseases are associated with oxidative stress that is induced by the presence of reactive oxygen species and the abnormal cellular accumulation of transition metals. Here, a new series of orally bioavailable multifunctional antioxidants (MFAO-2s) possessing a 2-diacetylamino-5-hydroxypyrimidine moiety is described. These MFAO-2s demonstrate both free radical and metal attenuating properties that are similar to the original published MFAO-1s that are based on 1-N,N'-dimethylsulfamoyl-1-4-(2-pyrimidyl)piperazine. Oral bioavailability studies in C57BL/6 mice demonstrate that the MFAO-2s accumulate in the brain at significantly higher levels than the MFAO-1s while achieving similar neural retina levels. The MFAO-2s protect human neuroblastoma and retinal pigmented epithelial cells against hydroxyl radicals in a dose-dependent manner by maintaining cell viability and intracellular glutathione levels. The MFAO-2s outperform clioquinol, a metal attenuator that has been investigated for the treatment of Alzheimer's disease. PMID:26068053

  4. Polymeric nanoparticles assembled by metal ion chelation for radionuclide and drug delivery

    Czech Academy of Sciences Publication Activity Database

    Nováková, Michaela; Hrubý, Martin; Filippov, Sergey K.; Karlsson, G.; Macková, Hana; Větvička, David; Špírková, Milena; Kaňková, Dana; Steinhart, Miloš; Štěpánek, Petr; Ulbrich, Karel

    Kottayam : Institute for Holistic Medical Sciences, 2011. s. 21-22. [World Conference on Nanomedicine and Drug Delivery /2./. 11.03.2011-13.03.2011, Kottayam] R&D Projects: GA ČR GPP207/10/P054; GA ČR GA202/09/2078; GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50200510 Keywords : polymer * drug delivery * metal ion assembly Subject RIV: CD - Macromolecular Chemistry

  5. A new method for the rapid identification of tetracycline residues in foods of animal origin - using the Premi?Test in combination with a metal ion chelation assay

    OpenAIRE

    Stead, Sara Lucy; Caldow, Marianne; Sharma, Anisha; Ashwin, Helen Mary; De-Rijk, Angelique; Stark, Jaques

    2007-01-01

    Abstract A post-screening classification assay for tetracycline compounds has been developed and integrated into the previously reported optimised Premi?Test methodology (Stead et al. 2004 and Stead et al. 2005) The new post-antimicrobial screening assay is based on a metal ion chelation using calcium and sodium chloride and has been shown to be specific towards the tetracycline class. The assay is both cost-effective and complementary to the post-screening procedures that have pre...

  6. CONTINUOUS CHELATION-EXTRACTION PROCESS FOR THE SEPARATION AND PURIFICATION OF METALS

    Science.gov (United States)

    Thomas, J.R.; Hicks, T.E.; Rubin, B.; Crandall, H.W.

    1959-12-01

    A continuous process is presented for separating metal values and groups of metal values from each other. A complex mixture. e.g., neutron-irradiated uranium, can be resolved into component parts. In the present process the values are dissolved in an acidic solution and adjusted to the proper oxidation state. Thenceforth the solution is contacted with an extractant phase comprising a fluorinated beta -diketone in an organic solvent under centain pH conditions whereupon plutonium and zirconium are extracted. Plutonium is extracted from the foregoing extract with reducing aqueous solutions or under specified acidic conditions and can be recovered from the aqueous solution. Zirconium is then removed with an oxalic acid aqueous phase. The uranium is recovered from the residual original solution using hexone and hexone-diketone extractants leaving residual fission products in the original solution. The uranium is extracted from the hexone solution with dilute nitric acid. Improved separations and purifications are achieved using recycled scrub solutions and the "self-salting" effect of uranyl ions.

  7. A simple sol–gel approach to synthesize nanocrystalline 8 mol% yttria stabilized zirconia from metal-chelate precursors: Microstructural evolution and conductivity studies

    International Nuclear Information System (INIS)

    A facile non alkoxide based sol–gel technique has been used to synthesize homogeneously distributed nanocrystalline 8 mol% yttria stabilized zirconia (YSZ) powder. The two steps of such powder preparation are gelation and thermal decomposition of metal-chelate complex in aqueous solution. Such nano powder was characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Field emission scanning electron microscope (FESEM), Fourier transform infra-red spectroscopy (FTIR) and BET surface area analyser. Upon calcinations at 600 °C, well crystallized nano-sized (10–15 nm) YSZ powder is obtained having spherical morphology and reasonably high surface area. The required ionic conductivity (0.107 S/cm) is achieved with 1200 °C sintered samples when measured at 1000 °C in air. - Graphical abstract: A facile non-alkoxide sol–gel route based on metal-EDTA chelate precursor is provided to synthesize dense nanocrystalline YSZ for use as SOFC electrolyte. - Highlights: • Facile one-step non-alkoxide based sol–gel approach. • Nanocrystalline YSZ synthesis from metal-chelate complex. • High ionic conductivity at low sintering temperature

  8. Flow-injection in-line complexation for ion-pair reversed phase high performance liquid chromatography of some metal-4-(2-pyridylazo) resorcinol chelates.

    Science.gov (United States)

    Srijaranai, Supalax; Chanpaka, Saiphon; Kukusamude, Chutima; Grudpan, Kate

    2006-02-28

    Flow injection (FI) was coupled to ion-pair reversed phase high performance liquid chromatography (IP-RPHPLC) for the simultaneous analysis of some metal-4-(2-pyridylazo) resorcinol (PAR) chelates. A simple reverse flow injection (rFI) set-up was used for in-line complexation of metal-PAR chelates prior to their separation by IP-RPHPLC. The rFI conditions were: injection volume of PAR 85muL, flow rate of metal stream 4.5mLmin(-1), concentration of PAR 1.8x10(-4)molL(-1) and the mixing coil length of 150cm. IP-RPHPLC was carried out using a C(18)muBondapak column with the mobile phase containing 37% acetonitrile, 3.0mmolL(-1) acetate buffer pH 6.0 and 6.2mmolL(-1) tetrabutylammonium bromide (TBABr) at a flow rate of 1.0mLmin(-1) and visible detection at 530 and 440nm. The analysis cycle including in-line complexation and separation by IP-RPHPLC was 16min, which able to separate Cr(VI) and the PAR chelates of Co(II), Ni(II) and Cu(II). PMID:18970520

  9. A simple sol–gel approach to synthesize nanocrystalline 8 mol% yttria stabilized zirconia from metal-chelate precursors: Microstructural evolution and conductivity studies

    Energy Technology Data Exchange (ETDEWEB)

    Bagchi, Biswajoy; Basu, Rajendra Nath, E-mail: ragenbasu54@gmail.com

    2015-10-25

    A facile non alkoxide based sol–gel technique has been used to synthesize homogeneously distributed nanocrystalline 8 mol% yttria stabilized zirconia (YSZ) powder. The two steps of such powder preparation are gelation and thermal decomposition of metal-chelate complex in aqueous solution. Such nano powder was characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Field emission scanning electron microscope (FESEM), Fourier transform infra-red spectroscopy (FTIR) and BET surface area analyser. Upon calcinations at 600 °C, well crystallized nano-sized (10–15 nm) YSZ powder is obtained having spherical morphology and reasonably high surface area. The required ionic conductivity (0.107 S/cm) is achieved with 1200 °C sintered samples when measured at 1000 °C in air. - Graphical abstract: A facile non-alkoxide sol–gel route based on metal-EDTA chelate precursor is provided to synthesize dense nanocrystalline YSZ for use as SOFC electrolyte. - Highlights: • Facile one-step non-alkoxide based sol–gel approach. • Nanocrystalline YSZ synthesis from metal-chelate complex. • High ionic conductivity at low sintering temperature.

  10. Some aspects of chelation chemistry

    International Nuclear Information System (INIS)

    The notions used in chelation chemistry are defined and the possibilities of the experimental recognition of complex formation are described. A review of the quantitative aspects of chelation is given, especially under biological conditions. Some rules concerning the general behaviour of the various metal ions and the organic ligands in chelation phenomena are presented and the specificity problem is discussed. The present status of the decontamination of the main fission products, e.g. rare-earth metals and strontium, with the aid of complexing agents is analysed from a chemical point of view. (author)

  11. DNA interaction and efficient antimicrobial activities of 4N chelating metal complexes.

    Science.gov (United States)

    Packianathan, S; Arun, T; Raman, N

    2015-07-01

    A new series of metal(II) complexes using a symmetric Schiff base ligand, obtained by the condensation reaction of 4-formyl-N,N-dimethylaniline with benzene-1,2-diamine were synthesized and characterized. The various physico-chemical data indicate that the complexes have octahedral geometry. The intrinsic binding constant of the complexes with DNA is explored. The UV-Vis., circular dichorism, fluorescence emission spectral data and the viscosity measurements indicate that the complexes bind to calf thymus DNA (CT DNA) by intercalative mode. The intrinsic binding constants of Cu(II), Ni(II), Co(II) and Zn(II) complexes are found to be 7.1×10(4), 5.2×10(4), 1.8×10(5) and 6.3×10(4) M(-1), respectively. The cleavage studies of these complexes are investigated by gel electrophoresis method in the presence of peroxide. The complexes exhibit enhanced biological activities compared to the free ligand. PMID:25931401

  12. RECOVERY OF CYCLODEXTRIN GLUCANOTRANSFERASE (CGTase USING IMMOBILIZED METAL CHELATING AFFINITY CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    M. Sivapragasam

    2015-03-01

    Full Text Available Abstract Immobilized metal affinity chromatography (IMAC was chosen as a method of purification for the recovery of CGTase from E. coli homogenate. E. coli harbouring the Bacillus sp. G1 gene expressed extracellularly secreted CGTase into ampicillin supplied LB broth. Culture was pre-purified using SnakeSkin dialysis tubing (3.5 MWCO with an enzyme activity of 147.80 U/mL. Three strategies (A, B and C were employed for the purification of CGTase using column adsorption chromatography with Ni2+-Sepharose resin. Strategy A employed an elution buffer of 50 mM EDTA, pH 7, Strategy B used 0.1 M imidazole, pH 7 and Strategy C employed 45 mM imidazole pH 7 as the elution buffer. Strategy C was found to be most suitable yielding a total CGTase recovery of 87.04% from an initial activity of 147.80 U/mL.

  13. Synthesis, Characterization and Some Properties of Chelating Polymers for Metal Ion Sorption

    International Nuclear Information System (INIS)

    Ion-exchange membranes have been prepared by radiation induced grafting using simultaneous technique based on low cost starting material and established process technologies. Methacrylic acid (MAA) and styrene (Sty) were selected as the grafted monomers to provide two different types of functional groups. Currently; there is much on going research for developing non fluorinated polymers with better performance and lower cost as alternative ion exchange membrane materials. The polymer chosen for this study is low density polyethylene (LDPE) film of two different thicknesses (40 and 70μm). The influence of grafting conditions, i.e. the effect of total irradiation dose and comonomer concentration and compositions have been investigated. These are important parameters in correlation with the grafting yield because they can markedly influence the composition of the resulting copolymer. Once grafted, the materials were readily sulfonated using concentrated sulfuric acid or chlorosulfonic acid in dichloroethane to produce a selection of graft copolymers with performer properties. The grafting and sulfonation of the membranes were confirmed by (FTIR) X-ray diffraction (XRD) and thermal analysis (TGA, DSC). The physicochemical properties of the prepared membranes such as, ion exchange capacity (IEC), equilibrium swelling and electrical conductivity of the grafted membranes and their derivatives were investigated as a function of composition and degree of grafting. The range of ion exchange capacities obtained with different degrees of grafting of MAA/Sty of composition (50/50) that sulfonated with sulfuric acid was in the range of 1.9-3.4 meq/g, whenever, for membranes that sulfonated with chlorosulfonic acid the IEC of 4.2 meq/g was achieved which is better than most of the commercially available membranes in addition to their low cost. The possibility of practicable use of membranes in various fields, such as the removal of some heavy metal ions is investigated.

  14. Molecular Mechanism of Heavy Metal Toxicity and Tolerance in Plants: Central Role of Glutathione in Detoxification of Reactive Oxygen Species and Methylglyoxal and in Heavy Metal Chelation

    Directory of Open Access Journals (Sweden)

    Mohammad Anwar Hossain

    2012-01-01

    Full Text Available Heavy metal (HM toxicity is one of the major abiotic stresses leading to hazardous effects in plants. A common consequence of HM toxicity is the excessive accumulation of reactive oxygen species (ROS and methylglyoxal (MG, both of which can cause peroxidation of lipids, oxidation of protein, inactivation of enzymes, DNA damage and/or interact with other vital constituents of plant cells. Higher plants have evolved a sophisticated antioxidant defense system and a glyoxalase system to scavenge ROS and MG. In addition, HMs that enter the cell may be sequestered by amino acids, organic acids, glutathione (GSH, or by specific metal-binding ligands. Being a central molecule of both the antioxidant defense system and the glyoxalase system, GSH is involved in both direct and indirect control of ROS and MG and their reaction products in plant cells, thus protecting the plant from HM-induced oxidative damage. Recent plant molecular studies have shown that GSH by itself and its metabolizing enzymes—notably glutathione S-transferase, glutathione peroxidase, dehydroascorbate reductase, glutathione reductase, glyoxalase I and glyoxalase II—act additively and coordinately for efficient protection against ROS- and MG-induced damage in addition to detoxification, complexation, chelation and compartmentation of HMs. The aim of this review is to integrate a recent understanding of physiological and biochemical mechanisms of HM-induced plant stress response and tolerance based on the findings of current plant molecular biology research.

  15. Grafting iminodiacetic acid on silica nanoparticles for facilitated refolding of like-charged protein and its metal-chelate affinity purification.

    Science.gov (United States)

    Liu, Hu; Dong, Xiaoyan; Sun, Yan

    2016-01-15

    A series of highly charged nanoscale chelators were fabricated by grafting of poly(glycidyl methacrylate-iminodiacetic acid) (pGI) chains with iminodiacetic acid (IDA) chelating group on silica nanoparticles (SNPs) via atom transfer radical polymerization (ATRP). The nanoscale chelators, denoted as SNPs-pGI, possessed a nickel ion chelating capacity as high as 2800 μmol/g, 50 times higher than the IDA-modified Sepharose FF (IDA-Sepharose) resin reported in literature and offered a high affinity binding capacity for hexahistidine-tagged enhanced green fluorescence protein (6 × His-EGFP) after nickel ion loading. More importantly, the anionic SNPs-pGI of high charge densities displayed much better performance than IDA-Sepharose in facilitating the refolding of like-charged 6 × His-EGFP from inclusion bodies (IBs). For example, for 0.2mg/mL 6 × His-EGFP IB refolding, addition of 6.2 μL/mL SNPs-pGI with the highest charge density led to a refolding yield of 90%, over 43% higher than that obtained with 460 μL/mL IDA-Sepharose. It is notable that the much higher efficiency of the nanoscale chelator was obtained with a chelator consumption corresponding to only 1.4% of IDA-Sepharose. Moreover, the highly charged SNPs-pGI could efficiently facilitate the refolding of 6 × His-EGFP at higher IB concentrations (0.4 and 0.8 mg/mL). After refolding, nickel ions addition led to the recovery of the refolded 6 × His-EGFP with high yield (80%), purity (96%) and enrichment ratio (1.8). All the results suggest that the SNPs-pGI of high charge densities were promising for cost-effective recovery of His-tagged proteins expressed as IBs with the integrative like-charge facilitated refolding and metal-chelate affinity purification strategy. PMID:26755413

  16. COMPARATIVE STUDY OF CHELATION VALUE OF SEVENTEEN PERCENT SELF DEVELOPED AND COMMERCIALLY AVAILABLE ROOT CANAL LUBRICANTS

    OpenAIRE

    Ingale Satish Dinkarrao; Kankariya Rajendra

    2013-01-01

    The main objective of this study is to compare chelation values of 17% self developed & commercially available root canal Lubricants or dental chelating gels as well as to see whether their performance depends on the chelation value or not. The Chelating agent bounds Ca2+ ions of the smear layer & the extent of chelate formation between chelating agent and metal ion is nothing but Chelation Value. Sodium carbonate indicator method is used for determinations of chelation value. Commercially av...

  17. Field-portable and automated immunosensors for hexavalent uranium, other heavy metals and chelators. Final Report

    International Nuclear Information System (INIS)

    This is the final technical report for this 10-year project. A better understanding of in situ bioremediation processes and the development of strategies to enhance bacterial remediation of contaminated sites depend either directly or indirectly upon accurate detection and measurement of organics, metal and other toxic elements prior to, during and following the remediation process. Detection and measurement costs are presently high due to the complex methodologies required for analysis. Remediation costs could be significantly reduced through the use of rapid, simple on-site methods. The cost of laboratory analysis continues to climb and the outlay for the assessment of a single site can frequently reach hundreds of thousands of dollars. One estimate suggests that the use of low cost field methods (defined as less than $100/test) with 5-20% standard laboratory confirmation could reduce analytical costs by greater than 70%. Perhaps as important as the cost of analysis is ability to obtain data about the remediation process in near real-time. The instruments normally used for environmental analysis of uranium (atomic absorption spectrophotometer, inductive coupled plasma emission spectrometer, IC-MS and kinetic phosphorescence analyzer) or can be quite expensive; these instruments are thus usually located only in centralized facilities. Environmental samples must therefore be transported to these facilities and often wait in a queue before they can be analyzed. Both sample transport and time-in-queue lead to long turn-around times (days to weeks). Such long turn-around times are especially worrisome during site remediation, especially when an unexpected finding might dictate a change in the methodologies being employed at the site. The goal of this project was to develop sensors that could yield reliable data in near realtime (< 1 hour) be field-ready (ie, simple, durable and accurate) and present low costs (<< $100/assay and <$5,000 for the initial equipment

  18. Heavy metal removal from sludge with organic chelators: Comparative study of N, N-bis(carboxymethyl) glutamic acid and citric acid.

    Science.gov (United States)

    Suanon, Fidèle; Sun, Qian; Dimon, Biaou; Mama, Daouda; Yu, Chang-Ping

    2016-01-15

    The applicability and performance of a new generation of biodegradable chelator, N, N-Bis(carboxymethyl) glutamic acid (GLDA), for extracting heavy metals from sewage sludge was carried out and compared with citric acid (CA). Targeted metals included Cd, Co, Cu, Zn, Ni and Cr, and their contents in the raw sludge were 63.1, 73.4, 1103.2, 2060.3, 483.9 and 604.1 mg kg(-1) (dry sludge basis), respectively. Metals were divided into six fractions including water soluble, exchangeable, carbonates bound, Fe-Mn bound, organic matters bound and residual fraction via chemical fractionation. Washing results showed that in general GLDA exhibited better performance compared with CA, with removal efficiency of 83.9, 87.3, 81.2, 85.6, 89.3 and 90.2% for Cd, Co, Cu, Zn, Ni and Cr, respectively at equilibrium pH = 3.3. Residual metals were better stabilized in the GLAD-washed sludge than in the CA-washed sludge, and were mostly tightly bonded to the residual fraction. Furthermore, CA promoted phosphorus (P) release while GLDA had an opposite effect and tended to retain P within sludge, which could be beneficial for further application in agricultural use. Findings from this study suggested that GLDA could be a potential replacement for refractory and less environmentally-friendly chelators in the extraction of metals from sludge. PMID:26520041

  19. Preparation and characterization of chelating fibers based on natural wool for removal of Hg(II), Cu(II) and Co(II) metal ions from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Monier, M., E-mail: monierchem@yahoo.com [Chemistry Department, Faculty of Science, Mansoura University, 35516 (Egypt); Nawar, N., E-mail: nnawar@mans.edu.eg [Chemistry Department, Faculty of Science, Mansoura University, 35516 (Egypt); Abdel-Latif, D.A. [Chemistry Department, Faculty of Science, Mansoura University, 35516 (Egypt)

    2010-12-15

    The graft copolymerization of acrylonitrile (AN) onto natural wool fibers initiated by KMnO{sub 4} and oxalic acid combined redox initiator system in limited aqueous medium was carried out in heterogeneous media. Moreover, modification of the grafted wool fibers was done by changing the nitrile group (-CN) into cyano-acetic acid {alpha}-amino-acrylic-hydrazide through the reaction with hydrazine hydrate followed by ethylcyanoacetate which eventually produce wool-grafted-poly(cyano-acetic acid {alpha}-amino-acrylic-hydrazide) (wool-g-PCAH) chelating fibers. The application of the modified fibers for metal ion uptake was studied using Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+}. The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.

  20. Preparation and characterization of chelating fibers based on natural wool for removal of Hg(II), Cu(II) and Co(II) metal ions from aqueous solutions.

    Science.gov (United States)

    Monier, M; Nawar, N; Abdel-Latif, D A

    2010-12-15

    The graft copolymerization of acrylonitrile (AN) onto natural wool fibers initiated by KMnO(4) and oxalic acid combined redox initiator system in limited aqueous medium was carried out in heterogeneous media. Moreover, modification of the grafted wool fibers was done by changing the nitrile group (-CN) into cyano-acetic acid α-amino-acrylic-hydrazide through the reaction with hydrazine hydrate followed by ethylcyanoacetate which eventually produce wool-grafted-poly(cyano-acetic acid α-amino-acrylic-hydrazide) (wool-g-PCAH) chelating fibers. The application of the modified fibers for metal ion uptake was studied using Hg(2+), Cu(2+) and Co(2+). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction. PMID:20810212

  1. Preparation and characterization of chelating fibers based on natural wool for removal of Hg(II), Cu(II) and Co(II) metal ions from aqueous solutions

    International Nuclear Information System (INIS)

    The graft copolymerization of acrylonitrile (AN) onto natural wool fibers initiated by KMnO4 and oxalic acid combined redox initiator system in limited aqueous medium was carried out in heterogeneous media. Moreover, modification of the grafted wool fibers was done by changing the nitrile group (-CN) into cyano-acetic acid α-amino-acrylic-hydrazide through the reaction with hydrazine hydrate followed by ethylcyanoacetate which eventually produce wool-grafted-poly(cyano-acetic acid α-amino-acrylic-hydrazide) (wool-g-PCAH) chelating fibers. The application of the modified fibers for metal ion uptake was studied using Hg2+, Cu2+ and Co2+. The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.

  2. Stability and Biodistribution of Thiol-Functionalized and (177)Lu-Labeled Metal Chelating Polymers Bound to Gold Nanoparticles.

    Science.gov (United States)

    Yook, Simmyung; Lu, Yijie; Jeong, Jenny Jooyoung; Cai, Zhongli; Tong, Lemuel; Alwarda, Ramina; Pignol, Jean-Philippe; Winnik, Mitchell A; Reilly, Raymond M

    2016-04-11

    We are studying a novel radiation nanomedicine approach to treatment of breast cancer using 30 nm gold nanoparticles (AuNP) modified with polyethylene glycol (PEG) metal-chelating polymers (MCP) that incorporate 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelators for complexing the β-particle emitter, (177)Lu. Our objective was to compare the stability of AuNP conjugated to MCP via a single thiol [DOTA-PEG-ortho-pyridyl disulfide (OPSS)], a dithiol [DOTA-PEG-lipoic acid (LA)] or multithiol end-group [PEG-pGlu(DOTA)8-LA4] and determine the elimination and biodistribution of these (177)Lu-labeled MCP-AuNP in mice. Stability to aggregation in the presence of thiol-containing dithiothreitol (DTT), l-cysteine or glutathione was assessed and dissociation of (177)Lu-MCP from AuNP in human plasma measured. Elimination of radioactivity from the body of athymic mice and excretion into the urine and feces was measured up to 168 h post-intravenous (i.v.) injection of (177)Lu-MCP-AuNP and normal tissue uptake was determined. ICP-AES was used to quantify Au in the liver and spleen and these were compared to (177)Lu. Our results showed that PEG-pGlu(DOTA)8-LA4-AuNP were more stable to aggregation in vitro than DOTA-PEG-LA-AuNP and both forms of AuNP were more stable to thiol challenge than DOTA-PEG-OPSS-AuNP. PEG-pGlu((177)Lu-DOTA)8-LA4 was the most stable in plasma. Whole body elimination of (177)Lu was most rapid for mice injected with (177)Lu-DOTA-PEG-OPSS-AuNP. Urinary excretion accounted for >90% of eliminated (177)Lu. All (177)Lu-MCP-AuNP accumulated in the liver and spleen. Liver uptake was lowest for PEG-pGlu((177)Lu-DOTA)8-LA4-AuNP but these AuNP exhibited the greatest spleen uptake. There were differences in Au and (177)Lu in the liver for PEG-pGlu((177)Lu-DOTA)8-LA4-AuNP. These differences were not correlated with in vitro stability of the (177)Lu-MCP-AuNP. We conclude that conjugation of AuNP with PEG-pGlu((177)Lu-DOTA)8-LA4 via a multithiol

  3. Paramagnetic relaxation enhancement of membrane proteins by incorporation of the metal-chelating unnatural amino acid 2-amino-3-(8-hydroxyquinolin-3-yl)propanoic acid (HQA)

    International Nuclear Information System (INIS)

    The use of paramagnetic constraints in protein NMR is an active area of research because of the benefits of long-range distance measurements (>10 Å). One of the main issues in successful execution is the incorporation of a paramagnetic metal ion into diamagnetic proteins. The most common metal ion tags are relatively long aliphatic chains attached to the side chain of a selected cysteine residue with a chelating group at the end where it can undergo substantial internal motions, decreasing the accuracy of the method. An attractive alternative approach is to incorporate an unnatural amino acid that binds metal ions at a specific site on the protein using the methods of molecular biology. Here we describe the successful incorporation of the unnatural amino acid 2-amino-3-(8-hydroxyquinolin-3-yl)propanoic acid (HQA) into two different membrane proteins by heterologous expression in E. coli. Fluorescence and NMR experiments demonstrate complete replacement of the natural amino acid with HQA and stable metal chelation by the mutated proteins. Evidence of site-specific intra- and inter-molecular PREs by NMR in micelle solutions sets the stage for the use of HQA incorporation in solid-state NMR structure determinations of membrane proteins in phospholipid bilayers

  4. Paramagnetic relaxation enhancement of membrane proteins by incorporation of the metal-chelating unnatural amino acid 2-amino-3-(8-hydroxyquinolin-3-yl)propanoic acid (HQA)

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Ho; Wang, Vivian S.; Radoicic, Jasmina; Angelis, Anna A. De; Berkamp, Sabrina; Opella, Stanley J., E-mail: sopella@ucsd.edu [University of California, San Diego, Department of Chemistry and Biochemistry (United States)

    2015-04-15

    The use of paramagnetic constraints in protein NMR is an active area of research because of the benefits of long-range distance measurements (>10 Å). One of the main issues in successful execution is the incorporation of a paramagnetic metal ion into diamagnetic proteins. The most common metal ion tags are relatively long aliphatic chains attached to the side chain of a selected cysteine residue with a chelating group at the end where it can undergo substantial internal motions, decreasing the accuracy of the method. An attractive alternative approach is to incorporate an unnatural amino acid that binds metal ions at a specific site on the protein using the methods of molecular biology. Here we describe the successful incorporation of the unnatural amino acid 2-amino-3-(8-hydroxyquinolin-3-yl)propanoic acid (HQA) into two different membrane proteins by heterologous expression in E. coli. Fluorescence and NMR experiments demonstrate complete replacement of the natural amino acid with HQA and stable metal chelation by the mutated proteins. Evidence of site-specific intra- and inter-molecular PREs by NMR in micelle solutions sets the stage for the use of HQA incorporation in solid-state NMR structure determinations of membrane proteins in phospholipid bilayers.

  5. The assembly of metals chelation by thiols and vacuolar compartmentalization conferred increased tolerance to and accumulation of cadmium and arsenic in transgenic Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Highlights: ► Simultaneous transformation of AsPCS1 and ScYCF1 into Arabidopsis thaliana which is sensitive to heavy metals, leads to transgenic plants tolerant to Arsenic and cadmium. ► Dual-gene transgenic Arabidopsis showed higher accumulation of Arsenic and cadmium than single and non-transgenic plants. ► Our results proved that improved thiol peptides synthesis and vacuolar compartmentation in plant dramatically boosted the survival rates of plants when exposed to heavy metals. ► A new strategy for efficient phytoremediation of heavy metals by stacking genes transformation in plants was developed in this article. - Abstract: Transgenic Arabidopsis thaliana were developed to increase tolerance for and accumulation of heavy metals and metalloids by simultaneous overexpression of AsPCS1 and YCF1 (derived from garlic and baker's yeast) based on the fact that chelation of metals and vacuolar compartmentalization are the main strategies for heavy metals/metalloids detoxification and tolerance in plants. Dual-gene transgenic lines had the longest roots and the highest accumulation of Cd and As than single-gene transgenic lines and wildtype. When grown on cadmium or arsenic (arsenite/arsenate), Dual-gene transgenic lines accumulated over 2–10 folds cadmium/arsenite and 2–3 folds arsenate than wild type or plants expressing AsPCS1 or YCF1 alone. Such stacking modified genes involved in chelation of toxic metals and vacuolar compartmentalization represents a highly promising new tool for use in phytoremediation efforts.

  6. The assembly of metals chelation by thiols and vacuolar compartmentalization conferred increased tolerance to and accumulation of cadmium and arsenic in transgenic Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jiangbo [Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093 (China); Inner Mongolia Key Laboratory of Biomass-Energy Conversion, The Institute of Bioengineering and Technology, Inner Mongolia University of Science and Technology, Baotou 040100 (China); Xu, Wenzhong [Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093 (China); Ma, Mi, E-mail: mami@ibcas.ac.cn [Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093 (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Simultaneous transformation of AsPCS1 and ScYCF1 into Arabidopsis thaliana which is sensitive to heavy metals, leads to transgenic plants tolerant to Arsenic and cadmium. Black-Right-Pointing-Pointer Dual-gene transgenic Arabidopsis showed higher accumulation of Arsenic and cadmium than single and non-transgenic plants. Black-Right-Pointing-Pointer Our results proved that improved thiol peptides synthesis and vacuolar compartmentation in plant dramatically boosted the survival rates of plants when exposed to heavy metals. Black-Right-Pointing-Pointer A new strategy for efficient phytoremediation of heavy metals by stacking genes transformation in plants was developed in this article. - Abstract: Transgenic Arabidopsis thaliana were developed to increase tolerance for and accumulation of heavy metals and metalloids by simultaneous overexpression of AsPCS1 and YCF1 (derived from garlic and baker's yeast) based on the fact that chelation of metals and vacuolar compartmentalization are the main strategies for heavy metals/metalloids detoxification and tolerance in plants. Dual-gene transgenic lines had the longest roots and the highest accumulation of Cd and As than single-gene transgenic lines and wildtype. When grown on cadmium or arsenic (arsenite/arsenate), Dual-gene transgenic lines accumulated over 2-10 folds cadmium/arsenite and 2-3 folds arsenate than wild type or plants expressing AsPCS1 or YCF1 alone. Such stacking modified genes involved in chelation of toxic metals and vacuolar compartmentalization represents a highly promising new tool for use in phytoremediation efforts.

  7. Adsorption performances and mechanisms of the newly synthesized N,N'-di (carboxymethyl) dithiocarbamate chelating resin toward divalent heavy metal ions from aqueous media

    International Nuclear Information System (INIS)

    N,N'-di (carboxymethyl) dithiocarbamate chelating resin (PSDC) was synthesized by anchoring the chelating agent of N,N'-di (carboxymethyl) dithiocarbamate to the chloromethylated PS-DVB (Cl-PS-DVB) matrix, as a new adsorbent for removing divalent heavy metal ions from waste-stream. The physicochemical structures of Cl-PS-DVB and PSDC were elaborately characterized using Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), and were further morphologically characterized using BET and BJH methods. The adsorption performances of PSDC towards heavy metals such as Cu(II), Pb(II) and Ni(II) were systematically investigated, based upon which the adsorption mechanisms were deeply exploited. For the above target, the classic batch adsorption experiments were conducted to explore the kinetics and isotherms of the removal processes with pH-value, initial concentration, temperature, and contact time as the controlling parameters. The kinetic and isotherm data could be well elucidated with Lagergren-second-order equation and Langmuir model respectively. The strong affinity of PSDC toward these target soft acids could be well demonstrated with the electrostatic attraction and chelating interaction caused by IDA moiety and sulphur which were namely soft bases on the concept of hard and soft acids and bases (HASB). Thermodynamic parameters, involving ΔHo, ΔSo and ΔGo were also calculated from graphical interpretation of the experimental data. The standard heats of adsorption (ΔHo) were found to be endothermic and the entropy change values (ΔSo) were calculated to be positive for the adsorption of Cu(II), Pb(II) and Ni(II) ions onto the tested adsorbents. Negative values of ΔGo indicated that adsorption processes for all tested metal ions onto PSDC were spontaneous.

  8. Comparative evaluation of Metal Chelating, Antioxidant and Free Radical Scavenging activity of TROIS and six products commonly used to control pain and inflammation associated with Arthritis

    Directory of Open Access Journals (Sweden)

    NAITHANI V

    2011-12-01

    Full Text Available Arthritis is an inflammation of joints due to infectious, metabolic or constitutional cause usually accompanied with pain, swelling, and stiffness resulting from infection, trauma, degenerative changes, metabolic disturbances, or other causes. Free radicals damage biomolecules, including lipids, proteins and nucleic acids leading to various diseases including but not limited to arthritis. The objective of the study was to investigate and compare the free radical scavenging, metal chelating, DNA repair potential and nitric oxide inhibitory property of Trois (a nano-technology based research product indicated for the treatment of pain and inflammation associated with arthritis and with six commercial brands.

  9. Effect of chelating agents and metal ions on nickel bioavailability and chlorophyll fluorescence response in wheat- An approach for attenuation of Ni stress

    Directory of Open Access Journals (Sweden)

    Nilima Patnaik

    2012-08-01

    Full Text Available The objectives of the study are to analyze the physiological changes, biochemical alterations and attenuation of nickel toxicity effects in wheat seedlings under combined applications of Ni ions, metal chelators (EDTA/Citric Acid and metal ions (Zn2+ /Mg2+. Wheat (Triticum aestivum L cv UP262 seedlings were grown hydroponically using different concentrations of Ni up to 7 days along with chelators and metal ions for study. The seedling growth was maximum with NiCl2–Zn2+ (100μM and minimum with NiCl2–EDTA (100μM treatments. Total chlorophyll content was maximum in the seedlings treated with NiCl2-Zn2+ (100μM and minimum in NiCl2-EDTA (100μM treatments. NiCl2–EDTA (100μM showed less Fo and Fm values and therefore, a trend in the decrease in OJIP transient indicates the maximum alteration of photochemical activity of PS-II in presence of NiCl2–EDTA (100μM treatment. Similar observation was found by NiCl2 –EDTA (200μM treatment where Fo and Fm values were noted to decline. High nickel content in roots of the seedlings was noted as compared to shoots.

  10. Investigation on the influence of metal ion impurities on the complexation behavior of generator produced {sup 90}Y with different bifunctional chelators

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Usha; Gamre, Naresh; Chakravarty, Rubel; Pillai, Maroor Raghavan Ambikalmajan; Dash, Ashutosh [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Radiopharmaceuticals Div.

    2014-07-01

    While the {sup 90}Sr/{sup 90}Y generator is the exclusive source of obtaining 'no carrier added' {sup 90}Y for targeted therapy, the presence of trace metals in the radiolabeling solutions poses a serious challenge owing to their ability to diminish the {sup 90}Y complexation yields with bifunctional chelators (BFCs). p-SCN-Bn-PCTA is a novel ligand having faster complexation kinetics with a number of radiometals. In this work, a systematic investigation was performed to evaluate the chelating ability of p-SCN-Bn-PCTA for {sup 90}Y and the influence of trace metal ions on it's complexation with {sup 90}Y in comparison to p-SCN-Bn-DTPA and p-SCN-Bn-DOTA using {sup 90}YCl{sub 3} obtained from an electrochemical generator. Results from our study indicate that while p-SCN-Bn-PCTA gave very good radiolabeling yields with {sup 90}Y when the reaction was carried out by heating for few minutes, it was most sensitive to the presence of trace metals, especially Fe(III). An independent and useful observation is that p-SCN-Bn-PCTA could be considered as the ligand of choice for assessing the chemical purity of generator derived {sup 90}Y.

  11. Dissimilatory reduction of FeIII (EDTA) with microorganisms in the system of nitric oxide removal from the flue gas by metal chelate absorption

    Institute of Scientific and Technical Information of China (English)

    MA Bi-yao; LI Wei; JING Guo-hua; SHI Yao

    2004-01-01

    In the system of nitric oxide removal from the flue gas by metal chelate absorption, it is an obstacle that ferrous absorbents are easily oxidized by oxygen in the flue gas to ferric counterparts, which are not capable of binding NO. By adding iron metal or electrochemical method, FeIII (EDTA) can be reduced to FeII (EDTA). However, there are various drawbacks associated with these techniques. The dissimilatory reduction of FeIII (EDTA) with microorganisms in the system of nitric oxide removal by metal chelate absorption was investigated. Ammonium salt instead of nitrate was used as the nitrogen source, as nitrates inhibited the reduction of FeIII due to the competition between the two electron acceptors. Supplemental glucose and lactate stimulated the formation of FeII more than ethanol as the carbon sources. The microorganisms cultured at 50℃ were not very sensitive to the other experimental temperature, the reduction percentage of FeIII varied little with the temperature range of 30~50℃. Concentrated Na2CO3 solution was added to adjust the solution pH to an optimal pH range of 6~7. The overall results revealed that the dissimilatory ferric reducing microorganisms present in the mix-culture are probably neutrophilic, moderately thermophilic FeIII reducers.

  12. Fluid extraction using carbon dioxide and organophosphorus chelating agents

    Science.gov (United States)

    Smart, Neil G.; Wai, Chien M.; Lin, Yuehe; Kwang, Yak Hwa

    1998-01-01

    Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO.sub.2, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO.sub.2 and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process.

  13. Luminescent lanthanide chelates and methods of use

    Energy Technology Data Exchange (ETDEWEB)

    Selvin, Paul R. (Berkeley, CA); Hearst, John (Berkeley, CA)

    1997-01-01

    The invention provides lanthanide chelates capable of intense luminescence. The celates comprise a lanthanide chelator covalently joined to a coumarin-like or quinolone-like sensitizer. Exemplary sensitzers include 2- or 4-quinolones, 2- or 4-coumarins, or derivatives thereof e.g. carbostyril 124 (7-amino-4-methyl-2-quinolone), coumarin 120 (7-amino-4-methyl-2-coumarin), coumarin 124 (7-amino-4-(trifluoromethyl)-2-coumarin), aminomethyltrimethylpsoralen, etc. The chelates form high affinity complexes with lanthanides, such as terbium or europium, through chelator groups, such as DTPA. The chelates may be coupled to a wide variety of compounds to create specific labels, probes, diagnostic and/or therapeutic reagents, etc. The chelates find particular use in resonance energy transfer between chelate-lanthanide complexes and another luminescent agent, often a fluorescent non-metal based resonance energy acceptor. The methods provide useful information about the structure, conformation, relative location and/or interactions of macromolecules.

  14. Chelated minerals for poultry

    Directory of Open Access Journals (Sweden)

    SL Vieira

    2008-06-01

    Full Text Available Organic minerals have been subject of an increasing number of investigations recently. These compounds can be considered the most significant event regarding commercial forms of minerals targeting animal supplementation in the last decades. Minerals, especially metals, are usually supplemented in poultry feeds using cheap saline sources and have never required a lot of attention in terms of quality. On the other hand, definitions of organic minerals are very broad and frequently lead to confusion when decision-making becomes necessary. Organic minerals include any mineral bound to organic compounds, regardless of the type of existing bond between mineral and organic molecules. Proteins and carbohydrates are the most frequent candidates in organic mineral combinations. Organic fraction size and bond type are not limitations in organic mineral definition; however, essential metals (Cu, Fe, Zn, and Mn can form coordinated bonds, which are stable in intestinal lumen. Metals bound to organic ligands by coordinated bonds can dissociate within animal metabolism whereas real covalent bonds cannot. Chelated minerals are molecules that have a metal bound to an organic ligand through coordinated bonds; but many organic minerals are not chelates or are not even bound through coordinated bonds. Utilization of organic minerals is largely dependent on the ligand; therefore, amino acids and other small molecules with facilitated access to the enterocyte are supposed to be better utilized by animals. Organic minerals with ligands presenting long chains may require digestion prior to absorption. After absorption, organic minerals may present physiological effects, which improve specific metabolic responses, such as the immune response. Many studies have demonstrated the benefits of metal-amino acid chelates on animal metabolism, but the detection positive effects on live performance is less consistent.

  15. Role of chelates in treatment of cancer

    Directory of Open Access Journals (Sweden)

    Tripathi Laxmi

    2007-01-01

    Full Text Available Chelates are used in cancer as cytotoxic agent, as radioactive agent in imaging studies and in radioimmunotherapy. Various chelates based on ruthenium, copper, zinc, organocobalt, gold, platinum, palladium, cobalt, nickel and iron are reported as cytotoxic agent. Monoclonal antibodies labeled with radioactive metals such as yttrium-90, indium-111 and iodine-131 are used in radioimmunotherapy. This review is an attempt to compile the use of chelates as cytotoxic drugs and in radioimmunotherapy.

  16. Diamidophosphines with six-membered chelates and their coordination chemistry with group 4 metals: development of a trimethylene-methane-tethered [PN2]-type "molecular claw".

    Science.gov (United States)

    Batke, S; Kothe, T; Haas, M; Wadepohl, H; Ballmann, J

    2016-02-28

    The coordination chemistry of the phosphine-tethered diamidophosphine ligands PhP(CH2CH2CH2NHPh)2 (pr[NPN]H2) and PhP(1,2-CH2-C6H4-NHSiMe3)2 (bn[NPN]H2) featuring six-membered N–C3–P chelates was explored with group 4 metals, which allowed for the consecutive development of a new trimethylene-methane-tethered [PN2] scaffold. In the case of the propylene-linked system pr[NPN]H2, access to the sparingly soluble dibenzyl derivative pr[NPN]ZrBn2 (3-Zr) was gained, while thermally sensitive zirconium and hafnium diiodo complexes bn[NPN]MI2 (5-M, M = Zr, Hf) were isolated in the case of the benzylene-linked derivative bn[NPN]H2. Despite the related phosphine-tethered backbone architectures of both of these ligands, their group 4 complexes were found to exhibit either C1-symmetric (bn[NPN]MX2) or averaged CS-symmetric (pr[NPN]MX2) structures in solution. To restrain the overall flexibility of these systems and thereby control the properties of the resulting complexes without disrupting the six-membered chelates, the new trimethylene-methane-tethered N,N′-di-(tert-butyl)-substituted [PN2]H2 protioligand was designed. This tripodal ligand system was prepared on a gram scale and its CS-symmetric dichloro complexes [PN2]MCl2 (6-M, M = Ti, Zr, Hf) were isolated subsequently. The benzene-soluble dibenzyl derivative [PN2]ZrBn2 (7-Zr) was synthesised as well and characterised by X-ray diffraction. These results are discussed not only in conjunction with the known [NPN]-coordinated group 4 complexes incorporating five-membered chelates, but also in the context of “molecular claws” that are related to the new [PN2] tripod. PMID:26804587

  17. Equilibrium study of the complex formation of some trivalent metal ion chelates of Schiff bases derived from 2-hydroxy-3-phenyl benzaldehyde and evaluation of these reagents from their anticoagulant activity

    International Nuclear Information System (INIS)

    Potentiometric studies have been carried out on metal chelates of La3+, Pr3+, Gd3+, Tb3+, Dy3+, Er3+ and Yb3+ with N-(2-hydroxy-3-phenylbenz ylidene)-aniline and N-(2-hydroxy-3-phenylbenzylidene)-3, 4, 5 trimethoxyaniline. The dissociatio n constants of the reagents and formation constants of their metal chelates have been determine d by Calvin-Bjerrum pH titration technique as adopted by Irving and Rossotti and at 28 ± 0.1degC at ionic strength 0.1 M in 75:25 (v/v) dioxane-water mediium. (author). 7 figs., 5 refs

  18. Critical evaluation of equilibrium constants involving 8-hydroxyquinoline and its metal chelates critical evaluation of equilibrium constants in solution : part b : equilibrium constants of liquid-liquid distribution systems

    CERN Document Server

    Stary, J

    1979-01-01

    Critical Evaluation of Equilibrium Constants Involving 8-Hydroxyquinoline and Its Metal Chelates presents and evaluates the published data on the solubility, dissociation, and liquid-liquid distribution of oxine and its metal chelates to recommend the most reliable numerical data. This book explores the dissociation constants of oxine in aqueous solutions.Organized into four chapters, this book begins with an overview of the characteristics of 8-hydroxyquinoline (oxine). This text then examines the total solubility of oxine in aqueous solution at different pH values. Other chapters consider th

  19. Synthesis, characterization and application of a new chelating resin for solid phase extraction, preconcentration and determination of trace metals in some dairy samples by flame atomic absorption spectrometry.

    Science.gov (United States)

    Daşbaşı, Teslima; Saçmacı, Şerife; Çankaya, Nevin; Soykan, Cengiz

    2016-11-15

    In this study, a simple and rapid solid phase extraction/preconcentration procedure was developed for determination of Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Mn(II), Pb(II), and Zn(II) trace metals by flame atomic absorption spectrometry (FAAS). A new chelating resin, poly(N-cyclohexylacrylamide-co-divinylbenzene-co-2-acrylamido-2-methyl-1-propanesulfonic acid) (NCA-co-DVB-co-AMPS) (hereafter CDAP) was synthesized and characterized. The influences of the analytical parameters such as pH of the sample solution, type and concentration of eluent, flow rates of the sample and eluent, volume of the sample and eluent, amount of chelating resin, and interference of ions were examined. The limit of detection (LOD) of analytes were found (3s) to be in the range of 0.65-1.90μgL(-1). Preconcentration factor (PF) of 200 and the relative standard deviation (RSD) of ⩽2% were achieved (n=11). The developed method was applied for determination of analytes in some dairy samples and certified reference materials. PMID:27283608

  20. Study on solid phase extraction and flame atomic absorption spectrometry for the determination of some trace metals using a chromosorb 105 column and metal-1-(2-pyridylazo)-2-napthol chelates

    International Nuclear Information System (INIS)

    Complete text of publication follows. The aquatic environmental pollution by heavy metals has become a considerable problem for public and scientific concern due to their toxicity to human health. Therefore, determinations of toxic heavy metals, such as Fe(III), Zn(II), Pb(II) and Cu(II) have special importance in environmental samples. Many regulations including standard and reference methods for the determination of heavy metals have been presented. Flame atomic absorption spectrometry (FAAS) is widely used in the determination of heavy metals due to the simplicity of operation and low instrumental and operational cost. However, direct determination of ultra trace heavy metals presented in environmental samples is difficult because their amounts are mostly lower than the detection limit of instruments, and in addition to this nonsuitable matrix problems may occur. These limitations can be overcome by applying a clean up and/or preconcentration step prior to the determination step. Solid phase extraction(SPE) is one of the most efficient methods for separation and preconcentration of trace metal ions. The most simple SPE to be used in practice is based on adsorption of heavy metal ions as chelates. Thereby, in the present work, optimization studies on the retention of metal-1-(2-pyridylazo)-2-napthol (PAN) chelates throughout a column filled Chromosorb 105 resin were carried out for determination of trace metals in environmental samples by FAAS. In this work, firstly, all variables involved in the development of the preconcentration using a Chromosorb 105 column including, pH, sample and eluent volumes, sample and eluent flow rates, interfering effects, etc., were optimized to achieve the best analytical performance. The recovery values for the examined analytes higher than 95 % were obtained at pH 9.0. The preconcentration factors were over 75. The RSDs were <5 %.

  1. Hyperaccumulator oilcake manure as an alternative for chelate-induced phytoremediation of heavy metals contaminated alluvial soils.

    Science.gov (United States)

    Mani, Dinesh; Kumar, Chitranjan; Patel, Niraj Kumar

    2015-01-01

    The ability of hyperaccumulator oilcake manure as compared to chelates was investigated by growing Calendula officinalis L for phytoremediation of cadmium and lead contaminated alluvial soil. The combinatorial treatment T6 [2.5 g kg(-1) oilcake manure+5 mmol kg(-1) EDDS] caused maximum cadmium accumulation in root, shoot and flower up to 5.46, 4.74 and 1.37 mg kg(-1) and lead accumulation up to 16.11, 13.44 and 3.17 mg kg(-1), respectively at Naini dump site, Allahabad (S3). The treatment showed maximum remediation efficiency for Cd (RR=0.676%) and Pb (RR=0.202%) at Mumfordganj contaminated site (S2). However, the above parameters were also observed at par with the treatment T5 [2.5 g kg(-1) oilcake manure +2 g kg(-1) humic acid]. Applied EDDS altered chlorophyll-a, chlorophyll-b, and carotene contents of plants while application of oilcake manure enhanced their contents in plant by 3.73-8.65%, 5.81-17.65%, and 7.04-17.19%, respectively. The authors conclude that Calendula officinalis L has potential to be safely grown in moderately Cd and Pb-contaminated soils and application of hyperaccumulator oilcake manure boosts the photosynthetic pigments of the plant, leading to enhanced clean-up of the cadmium and lead-contaminated soils. Hence, the hyperaccumulator oilcake manure should be preferred over chelates for sustainable phytoremediation through soil-plant rhizospheric process. PMID:25397984

  2. COMPARATIVE STUDY OF CHELATION VALUE OF SEVENTEEN PERCENT SELF DEVELOPED AND COMMERCIALLY AVAILABLE ROOT CANAL LUBRICANTS

    Directory of Open Access Journals (Sweden)

    Ingale Satish Dinkarrao

    2013-06-01

    Full Text Available The main objective of this study is to compare chelation values of 17% self developed & commercially available root canal Lubricants or dental chelating gels as well as to see whether their performance depends on the chelation value or not. The Chelating agent bounds Ca2+ ions of the smear layer & the extent of chelate formation between chelating agent and metal ion is nothing but Chelation Value. Sodium carbonate indicator method is used for determinations of chelation value. Commercially available gel incorporated in this study was File Rite which has little bit higher chelation value. Self developed chelating gel or root canal lubricants have comparatively lower chelation value. Root canal lubricants having higher chelation value should perform better in shaping & cleaning of root canal better. However because of slight difference in chelation value of self developed & commercially available gel, no significant difference was found out as root canal lubricants, when applied in root canal for 5 minutes.

  3. Synthesis of heavy metal chelating agent with four chelating groups of N{sup 1},N{sup 2},N{sup 4},N{sup 5}-tetrakis(2-mercaptoethyl)benzene-1,2,4,5-tetracarboxamide (TMBTCA) and its application for Cu-containing wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng-He, E-mail: wangfenghe@njnu.edu.cn [Department of Environmental Science and Engineering, Nanjing Normal University, No.1 Wenyuan Road, Nanjing 210042 (China); Ji, Ying-Xue; Wang, Jun-Jie [Department of Environmental Science and Engineering, Nanjing Normal University, No.1 Wenyuan Road, Nanjing 210042 (China)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer A new heavy metal chelating agent of TMBTCA with four chelating groups was prepared and characterized. Black-Right-Pointing-Pointer The effects of mole ratio of reactants, reaction temperature, reaction time on the yield of TMBTCA were illustrated. Black-Right-Pointing-Pointer The effects of mole ratio of TMBTCA/Cu{sup 2+}, reaction time and pH on its application properties were researched. Black-Right-Pointing-Pointer This new chelating agent could effectively remove Cu{sup 2+} and CuEDTA to much lower than 0.5 mg/L. - Abstract: A novel heavy metal chelating agent, N{sup 1},N{sup 2},N{sup 4},N{sup 5}-tetrakis(2-mercaptoethyl) benzene-1,2,4,5-tetracarboxamide (TMBTCA), was designed with four chelating groups, and a facile one-step synthetic procedure was developed with pyromellitic dianhydride (PMDA) and cysteamine hydrochloride (CHC) as raw materials by aqueous acylation. The effects of mole ratio of reactants (CHC/PMDA), reaction temperature, and reaction time on the yield of TMBTCA were studied. Its application for Cu-containing wastewater was investigated. The experimental results showed that the maximum yield of TMBTCA was 75.92%, as the mole ratio of CHC/PMDA reached 4.8, reaction temperature was 5 Degree-Sign C, and reaction time was 6 h. It was observed that TMBTCA could effectively remove Cu{sup 2+} and CuEDTA to much lower than 0.5 mg/L (the discharge limit of copper ions in China). Furthermore, TMBTCA showed more affinity for cadmium and copper than some traditional commercial precipitants, such as DTC, TBA and TMT, via comparison of their ability for heavy metal removal, and the precipitates of Cu-TMBTCA and Cd-TMBTCA presented good stability in leaching tests. The results can provide a reference for design and further research on new kind of heavy metal chelating agent with more bonding sites, especially for heavy metal precipitation in PCB wastewater treatment.

  4. Chelation in metal intoxication XXX: α-mercapto-β-aryl acrylic acids as antidotes to cadmium toxicity

    International Nuclear Information System (INIS)

    α-Mercapto-β-(2-furyl) acrylic acid (MFA), α-mercapto-β-(2-hydroxyphenyl) acrylic acid (MHA), β-1,2-phenylene di-α-mercaptoacrylic acid (1,2-PDMA) and β-l,4-phenylene di-α-mercapto acrylic acid (1,4-PDMA) were compared to sodium N-benzyl-D-glucamine dithiocarbamate (NBG-DTC) an effective cadmium chelator, for their ability to mobilize Cd and influence the Cd induced tissue metallothionein (MT) in rats administered 109CdCl2, 72 hr earlier. MFA was almost as effective as NBG-DTC but more effective than MHA in enhancing urinary and faecal excretion of Cd, reducing tissue and blood levels of Cd and in lowering Cd induced increase in hepatic and renal MT contents. 1,2-PDMA and l,4-PDMA were effective only in reducing the hepatic burden of Cd. The results do not indicate any direct relationship between the efficacy of α-mercapto-β-aryl acrylic acids to decorporate body Cd and their lipophilic-hydrophilic character or number-arrangement of their sulfhydryl groups. (author)

  5. Site-specific tagging proteins with a rigid, small and stable transition metal chelator, 8-hydroxyquinoline, for paramagnetic NMR analysis

    International Nuclear Information System (INIS)

    Design of a paramagnetic metal binding motif in a protein is a valuable way for understanding the function, dynamics and interactions of a protein by paramagnetic NMR spectroscopy. Several strategies have been proposed to site-specifically tag proteins with paramagnetic lanthanide ions. Here we report a simple approach of engineering a transition metal binding motif via site-specific labelling of a protein with 2-vinyl-8-hydroxyquinoline (2V-8HQ). The protein-2V-8HQ adduct forms a stable complex with transition metal ions, Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The paramagnetic effects generated by these transition metal ions were evaluated by NMR spectroscopy. We show that 2V-8HQ is a rigid and stable transition metal binding tag. The coordination of the metal ion can be assisted by protein sidechains. More importantly, tunable paramagnetic tensors are simply obtained in an α-helix that possesses solvent exposed residues in positions i and i + 3, where i is the residue to be mutated to cysteine, i + 3 is Gln or Glu or i − 4 is His. The coordination of a sidechain carboxylate/amide or imidazole to cobalt(II) results in different structural geometries, leading to different paramagnetic tensors as shown by experimental data

  6. Site-specific tagging proteins with a rigid, small and stable transition metal chelator, 8-hydroxyquinoline, for paramagnetic NMR analysis.

    Science.gov (United States)

    Yang, Yin; Huang, Feng; Huber, Thomas; Su, Xun-Cheng

    2016-02-01

    Design of a paramagnetic metal binding motif in a protein is a valuable way for understanding the function, dynamics and interactions of a protein by paramagnetic NMR spectroscopy. Several strategies have been proposed to site-specifically tag proteins with paramagnetic lanthanide ions. Here we report a simple approach of engineering a transition metal binding motif via site-specific labelling of a protein with 2-vinyl-8-hydroxyquinoline (2V-8HQ). The protein-2V-8HQ adduct forms a stable complex with transition metal ions, Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The paramagnetic effects generated by these transition metal ions were evaluated by NMR spectroscopy. We show that 2V-8HQ is a rigid and stable transition metal binding tag. The coordination of the metal ion can be assisted by protein sidechains. More importantly, tunable paramagnetic tensors are simply obtained in an α-helix that possesses solvent exposed residues in positions i and i + 3, where i is the residue to be mutated to cysteine, i + 3 is Gln or Glu or i - 4 is His. The coordination of a sidechain carboxylate/amide or imidazole to cobalt(II) results in different structural geometries, leading to different paramagnetic tensors as shown by experimental data. PMID:26732873

  7. Site-specific tagging proteins with a rigid, small and stable transition metal chelator, 8-hydroxyquinoline, for paramagnetic NMR analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yin; Huang, Feng [Nankai University, State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) (China); Huber, Thomas [Australian National University, Research School of Chemistry (Australia); Su, Xun-Cheng, E-mail: xunchengsu@nankai.edu.cn [Nankai University, State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) (China)

    2016-02-15

    Design of a paramagnetic metal binding motif in a protein is a valuable way for understanding the function, dynamics and interactions of a protein by paramagnetic NMR spectroscopy. Several strategies have been proposed to site-specifically tag proteins with paramagnetic lanthanide ions. Here we report a simple approach of engineering a transition metal binding motif via site-specific labelling of a protein with 2-vinyl-8-hydroxyquinoline (2V-8HQ). The protein-2V-8HQ adduct forms a stable complex with transition metal ions, Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The paramagnetic effects generated by these transition metal ions were evaluated by NMR spectroscopy. We show that 2V-8HQ is a rigid and stable transition metal binding tag. The coordination of the metal ion can be assisted by protein sidechains. More importantly, tunable paramagnetic tensors are simply obtained in an α-helix that possesses solvent exposed residues in positions i and i + 3, where i is the residue to be mutated to cysteine, i + 3 is Gln or Glu or i − 4 is His. The coordination of a sidechain carboxylate/amide or imidazole to cobalt(II) results in different structural geometries, leading to different paramagnetic tensors as shown by experimental data.

  8. Synthesis, characterization and applications of polymer-metal chelates derived from poly[((4-acryloxy acetophenone)-divinylbenzene)] benzoyl hydrazone resins

    Indian Academy of Sciences (India)

    Thammisetty Ravi Sankar; K Kesavulu; Peddakotla Venkata Ramana

    2014-05-01

    4-Acryloxy acetophenone was prepared and subjected to suspension polymerization with divinylbenzene as a cross-linking agent. The resulting network polymer was ligated with benzoyl hydrazone. The functional polymer was treated with metal ions [Cu(II), Fe(II)]. The polymer-metal complexes obtained were characterized by elemental analysis, IR, 1H-NMR, solid state 13C cross-polarization magic-angle spinning (CP/MAS) NMR, electron paramagnetic resonance (EPR), thermogravimetric and scanning electron microscopy (SEM) studies. The maximum uptake efficiency for the metal ions was determined. The reusability of the polymer ligand was tested and it was shown that even after four cycles, the efficiency of the uptake was not altered.

  9. Paramagnetic effects on the NMR spectra of isotropic bicelles with headgroup modified chelator lipids and metal ions.

    Science.gov (United States)

    Tang, Ming; Mao, Kevin; Li, Stacey; Zhuang, Jianqin; Diallo, Koumba

    2016-06-21

    We characterized the paramagnetic effects of nine metal ions on NMR signals of isotropic bicelles with headgroup-modified lipids. We found that Mn(2+), Gd(3+) and Dy(3+) show evidence for influencing NMR signals on the surface more than inside and on the disc edge, providing distance information in the bilayers. PMID:27240538

  10. Cadmium chelation by frustulins: a novel metal tolerance mechanism in Nitzschia palea (Kützing) W. Smith.

    Science.gov (United States)

    Santos, José; Almeida, Salomé F P; Figueira, Etelvina

    2013-01-01

    The ubiquity of diatom distribution, species richness, short generation time, and specific sensitivity to several environmental stressors such as metals, make diatoms particularly useful for scientific studies. Anthropogenic activities have increased the concentration of metals in air, soil and water. Due to their toxicity and persistent character, the effects of metals on organisms have been extensively studied. In this work, the association of cadmium to different extracellular molecules of Nitzschia palea cells was investigated. Cells were grown in the absence and presence (0.2 mg l(-1)) of cadmium in Chu no. 10 medium. Extracellular polysaccharides were extracted, and subsamples were used for polysaccharide and Cd determination. The frustules were broken mechanically under liquid nitrogen and the intracellular and frustule fractions separated. Frustulins, a protein family found on the outmost frustule layer, constituting a protection coating to environmental stress, were extracted. In each fraction proteins were quantified by the BCA method and separated by gel electrophoresis (SDS-PAGE). Cadmium associated to each fraction was quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis. Exposure of Nitzschia palea to cadmium decreased extracellular polysaccharides by 52.8 % and increased 6 times the amount of frustulins. Cadmium was mostly retained extracellularly: 85.4 % was bound to the frustulin fraction, and 11.1 % to polysaccharides. The ability of Nitzschia palea to increase the production of frustulins due to the presence of Cd, the extracellular location of this frustulin coating and the ability of these proteins to bind Cd, suggests a new cellular defense mechanism to metals unknown until now. PMID:23124677

  11. Metal interactions with organic solids in estuarine waters : experiments on the combined effects of salinity and organic chelators

    OpenAIRE

    Förstner, Ulrich; Ahlf, Wolfgang; Calmano, Wolfgang; Sellhorn, Claudia

    1984-01-01

    In order to estimate the possible influence of nitrilotriacetic acid (NTA) on the sorption of metals in the estuarine environment (Hamburg Hr./Elbe River Estuary as a critical example containing strongly polluted sediments) laboratory experiments were performed using an organic substrate, which was prepared from cell walls of the algae Scenedesmus quadricauda. While the concentration of sodium chloride, calcium chloride and magnesium chloride exhibits relative small effects on the sorption of...

  12. Compression and immersion tests and leaching of radionuclides, stable metals, and chelating agents from cement-solidified decontamination waste collected from nuclear power stations

    Energy Technology Data Exchange (ETDEWEB)

    Akers, D.W.; Kraft, N.C.; Mandler, J.W. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

    1994-06-01

    A study was performed for the Nuclear Regulatory Commission (NRC) to evaluate structural stability and leachability of radionuclides, stable metals, and chelating agents from cement-solidified decontamination ion-exchange resin wastes collected from seven commercial boiling water reactors and one pressurized water reactor. The decontamination methods used at the reactors were the Can-Decon, AP/Citrox, Dow NS-1, and LOMI processes. Samples of untreated resin waste and solidified waste forms were subjected to immersion and compressive strength testing. Some waste-form samples were leach-tested using simulated groundwaters and simulated seawater for comparison with the deionized water tests that are normally performed to assess waste-form leachability. This report presents the results of these tests and assesses the effects of the various decontamination methods, waste form formulations, leachant chemical compositions, and pH of the leachant on the structural stability and leachability of the waste forms. Results indicate that releases from intact and degraded waste forms are similar and that the behavior of some radionuclides such as {sup 55}Fe, {sup 60}Co, and {sup 99}Tc were similar. In addition, the leachability indexes are greater than 6.0, which meets the requirement in the NRC`s ``Technical Position on Waste Form,`` Revision 1.

  13. Preparation of High-Efficiency Cytochrome c-Imprinted Polymer on the Surface of Magnetic Carbon Nanotubes by Epitope Approach via Metal Chelation and Six-Membered Ring.

    Science.gov (United States)

    Qin, Ya-Ping; Li, Dong-Yan; He, Xi-Wen; Li, Wen-You; Zhang, Yu-Kui

    2016-04-27

    A novel epitope molecularly imprinted polymer on the surface of magnetic carbon nanotubes (MCNTs@EMIP) was successfully fabricated to specifically recognize target protein cytochrome c (Cyt C) with high performance. The peptides sequences corresponding to the surface-exposed C-terminus domains of Cyt C was selected as epitope template molecule, and commercially available zinc acrylate and ethylene glycol dimethacrylate (EGDMA) were employed as functional monomer and cross-linker, respectively, to synthesize MIP via free radical polymerization. The epitope was immobilized via metal chelation and six-membered ring formed between the functional monomer and the hydroxyl and amino groups of the epitope. The resulting MCNTs@EMIP exhibited specific recognition ability toward target Cyt C including more satisfactory imprinting factor (about 11.7) than that of other reported imprinting methods. In addition, the MCNTs@EMIP demonstrated a high adsorption amount (about 780.0 mg g(-1)) and excellent selectivity. Besides, the magnetic property of the support material made the processes easy and highly efficient by assistance of an external magnetic field. High-performance liquid chromatography analysis of Cyt C in bovine blood real sample and protein mixture indicated that the specificity was not affected by other competitive proteins, which forcefully stated that the MCNTs@EMIP had potential to be applied in bioseparation area. In brief, this study provided a new protocol to detect target protein in complex sample via epitope imprinting approach and surface imprinting strategy. PMID:27049646

  14. Compression and immersion tests and leaching of radionuclides, stable metals, and chelating agents from cement-solidified decontamination waste collected from nuclear power stations

    International Nuclear Information System (INIS)

    A study was performed for the Nuclear Regulatory Commission (NRC) to evaluate structural stability and leachability of radionuclides, stable metals, and chelating agents from cement-solidified decontamination ion-exchange resin wastes collected from seven commercial boiling water reactors and one pressurized water reactor. The decontamination methods used at the reactors were the Can-Decon, AP/Citrox, Dow NS-1, and LOMI processes. Samples of untreated resin waste and solidified waste forms were subjected to immersion and compressive strength testing. Some waste-form samples were leach-tested using simulated groundwaters and simulated seawater for comparison with the deionized water tests that are normally performed to assess waste-form leachability. This report presents the results of these tests and assesses the effects of the various decontamination methods, waste form formulations, leachant chemical compositions, and pH of the leachant on the structural stability and leachability of the waste forms. Results indicate that releases from intact and degraded waste forms are similar and that the behavior of some radionuclides such as 55Fe, 60Co, and 99Tc were similar. In addition, the leachability indexes are greater than 6.0, which meets the requirement in the NRC's ''Technical Position on Waste Form,'' Revision 1

  15. Development of a Novel Optical Biosensor for Detection of Organophoshorus Pesticides Based on Methyl Parathion Hydrolase Immobilized by Metal-Chelate Affinity

    Directory of Open Access Journals (Sweden)

    Wensheng Lan

    2012-06-01

    Full Text Available We have developed a novel optical biosensor device using recombinant methyl parathion hydrolase (MPH enzyme immobilized on agarose by metal-chelate affinity to detect organophosphorus (OP compounds with a nitrophenyl group. The biosensor principle is based on the optical measurement of the product of OP catalysis by MPH (p-nitrophenol. Briefly, MPH containing six sequential histidines (6× His tag at its N-terminal was bound to nitrilotriacetic acid (NTA agarose with Ni ions, resulting in the flexible immobilization of the bio-reaction platform. The optical biosensing system consisted of two light-emitting diodes (LEDs and one photodiode. The LED that emitted light at the wavelength of the maximum absorption for p-nitrophenol served as the signal light, while the other LED that showed no absorbance served as the reference light. The optical sensing system detected absorbance that was linearly correlated to methyl parathion (MP concentration and the detection limit was estimated to be 4 μM. Sensor hysteresis was investigated and the results showed that at lower concentration range of MP the difference got from the opposite process curves was very small. With its easy immobilization of enzymes and simple design in structure, the system has the potential for development into a practical portable detector for field applications.

  16. Regeneration of three-way automobile catalysts using biodegradable metal chelating agent-S, S-ethylenediamine disuccinic acid (S, S-EDDS)

    International Nuclear Information System (INIS)

    Regeneration of the activity of three-way catalytic converters (TWCs) was tested for the first time using a biodegradable metal chelating agent (S, S-ethylenediamine disuccinic acid (S, S-EDDS). The efficiency of this novel environmentally friendly solvent in removing various contaminants such as P, Zn, Pb, Cu and S from commercial aged three-way catalysts, and improving their catalytic performance towards CO and NO pollutants removal has been investigated. Four samples of catalysts from the front and rear inlets of two different TWCs with different mileages and aged under completely different driving conditions were investigated. The catalysts were characterized using various techniques, such as X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area measurements (N2 adsorption at 77 K). Quantitative ICP-MS analyses and SEM-EDS studies show the removal of Zn, P and Pb. SEM-EDS images obtained at low magnification (50 μm) showed considerable differences in the surface morphology and composition after washing with S, S-EDDS. However, XRD studies indicated neither little to no removal of major contaminant compound phases nor major structural changes due to washing. Correspondingly, little or no enhancement in BET surface area was observed between the used and washed samples. Light-off curves show that the regeneration procedure employed can effectively improve the catalytic performance towards NO pollutant.

  17. Hinokitiol, a metal chelator derived from natural plants, suppresses cell growth and disrupts androgen receptor signaling in prostate carcinoma cell lines

    International Nuclear Information System (INIS)

    Hinokitiol (β-thujaplicin), a troplone-related compound found in the heartwood of cupressaceous plants, strongly inhibits the proliferation of a broad range of tumor cell lines. This is the first report to demonstrate that hinokitiol, a metal chelator derived from natural plants, suppresses cell growth and disrupts AR signaling in prostate carcinoma cell lines. Our present studies indicate that hinokitiol suppresses androgen/AR-mediated cell growth and androgen-stimulated DNA synthesis by [3H]thymidine incorporation in a dose- and time-dependent manner. Hinokitiol simultaneously suppresses the intracellular and secreted PSA levels, a marker for the progression of prostate cancer. Hinokitiol significantly represses the AR mRNA and protein expression in a dose- and time-dependent manner. Additionally, the ligand-binding assay shows that hinokitiol blocks binding of the synthetic androgen [3H]R1881 to AR in LNCaP cells. These findings collectively suggest that hinokitiol is potentially effective against prostate cancer in vitro, and thus it might become a novel chemopreventive or chemotherapeutic agent for prostate cancer

  18. Chelating agents in pharmacology, toxicology and therapeutics

    International Nuclear Information System (INIS)

    The proceedings contain 71 abstracts of papers. Fourteen abstracts were inputted in INIS. The topics covered include: the effects of chelating agents on the retention of 63Ni, 109Cd, 203Hg, 144Ce, 95Nb and the excretion of 210Po, 63Ni, 48V, 239Pu, 241Am, 54Mn; the applications of tracer techniques for studies of the efficacy of chelation therapy in patients with heart and brain disorders; and the treatment of metal poisoning with chelating agents. (J.P.)

  19. Evaluation of copper speciation in model solutions of humic acid by mini-columns packed with Chelex-100 and new chelating agents: Application to speciation of selected heavy metals in environmental water samples

    International Nuclear Information System (INIS)

    A solid-phase extraction procedure using mini-columns packed with Chelex-100 and two new chelating agents based on poly(vinyl chloride) functionalized with 3-ferrocenyl-3-hydroxydithioacrylic acid and N,N'-[1,1'-dithiobis(ethylene)]-bis(salicylideneimine) (H2sales) loaded on microcrystalline naphthalene, is reported. The columns were used to separate labile copper fractions in model solutions and in real samples with subsequent determination using electrothermal atomic absorption spectrometry (ETAAS). Various model solutions containing 20 μg L-1 of Cu2+ and 0.0, 0.2, 2.0 and 20.0 mg L-1 of humic acid, respectively, and buffered to pH 6.0, 7.0 and 8.0 were considered. Results showed a decrease in labile copper fraction with increase in humic acid concentration. Application of the procedure to speciation of Cu, Ni, Zn and Pb in various environmental water samples yielded labile fractions in the range of 1.67-55.75% against a total dissolved fraction of 44.08-69.77%. Comparison of the three chelating agents showed that H2sales had a weaker metal chelating strength than Chelex-100, but PVC-FSSH had comparable chelating strength to Chelex-100.

  20. Potentials and drawbacks of chelate-enhanced phytoremediation of soils

    NARCIS (Netherlands)

    Römkens, P.F.A.M.; Bouwman, L.A.; Japenga, J.; Draaisma, C.

    2002-01-01

    Chelate-enhanced phytoremediation has been proposed as an effective tool for the extraction of heavy metals from soils by plants. However, side-effects related to the addition of chelates, e.g. metal leaching and effects on soil micro-organisms, were usually neglected. Therefore, greenhouse and lysi

  1. Macrocyclic bifunctional chelating agents

    Science.gov (United States)

    Meares, Claude F.; DeNardo, Sally J.; Cole, William C.; Mol, Min K.

    1987-01-01

    A copper chelate conjugate which is stable in human serum. The conjugate includes the copper chelate of a cyclic tetraaza di-, tri-, or tetra-acetic acid, a linker attached at one linker end to a ring carbon of the chelate, and a biomolecule joined at the other end of the linker. The conjugate, or the linker-copper chelate compound used in forming the conjugate, are designed for use in diagnostic and therapeutic applications which involve Cu(II) localization via the systemic route.

  2. Rapid screening method for quinolone residues in livestock and fishery products using immobilised metal chelate affinity chromatographic clean-up and liquid chromatography-fluorescence detection.

    Science.gov (United States)

    Takeda, N; Gotoh, M; Matsuoka, T

    2011-09-01

    An efficient LC method was developed for screening the presence of quinolones (QLs)--comprising fluoroquinolones (FQs) and acidic quinolones (AQs)--residues in various livestock and fishery products. Targeted analytes were for nine FQs of marbofloxacin (MAR), ofloxacin (OFL), norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENR), danofloxacin (DAN), orbifloxacin (ORB), difloxacin (DIF) and sarafloxacin (SAR), and three AQs of oxolinic acid (OXA), nalidixic acid (NAL) and flumequine (FMQ). Samples comprised ten different food products covering five matrices: muscle (cattle, swine and chicken), liver (chicken), raw fish (shrimp and salmon), egg (chicken), and processed food (ham, sausage and fish sausage). This method involved a simple extraction with (1:1) acetonitrile-methanol, a highly selective clean-up with an immobilised metal chelate affinity column charged with Fe(3+), a fast isocratic LC analysis using a short column (20 mm × 4.6 mm, 3 µm) with a mobile phase of (15:85:0.1) methanol/water/formic acid, and fluorescence detection (excitation/emission wavelengths of 295 nm/455 nm for FQs (495 nm for MAR), and 320 nm/365 nm for AQs). Among FQs, pairs of NOR/OFL, ORB/DIF and ENR/DAN were incompletely resolved. A confirmatory LC run with a Mg(2+) containing methanolic mobile phase was also proposed for the samples suspected of being positive. The optimised method gave satisfactory recoveries of 88.5% (56.1-108.6%) and 78.7% (44.1-99.5%) for intra- and inter-day assays with relative standard deviations of 7.2% (0.7-18.4%) and 6.8% (1.4-16.6%), respectively. Limits of quantitation ranged from 0.8 µg kg(-1) (DAN) to 6.5 µg kg(-1) (SAR). This method was successfully employed to analyse 113 real samples and two positive samples were found: fish sausage (CIP 990 µg kg(-1)) and shrimp (ENR 20 µg kg(-1)). PMID:21749230

  3. Synthesis, characterization and biological approach of metal chelates of some first row transition metal ions with halogenated bidentate coumarin Schiff bases containing N and O donor atoms.

    Science.gov (United States)

    Prabhakara, Chetan T; Patil, Sangamesh A; Toragalmath, Shivakumar S; Kinnal, Shivashankar M; Badami, Prema S

    2016-04-01

    The impregnation of halogen atoms in a molecule is an emerging trend in pharmaceutical chemistry. The presence of halogens (Cl, Br, I and F) increases the lipophilic nature of molecule and improves the penetration of lipid membrane. The presence of electronegative halogen atoms increases the bio- activity of core moiety. In the present study, Co(II), Ni(II) and Cu(II) complexes are synthesised using Schiff bases (HL(I) and HL(II)), derived from 8-formyl-7-hydroxy-4-methylcoumarin/3-chloro-8-formyl-7-hydroxy-4-methylcoumarin with 2,4-difluoroaniline/o-toluidine respectively. The synthesized compounds were characterized by spectral (IR, NMR, UV-visible, Mass, ESI-MS, ESR), thermal, fluorescence and molar conductivity studies. All the synthesized metal complexes are completely soluble in DMF and DMSO. The non-electrolytic nature of the metal complexes was confirmed by molar conductance studies. Elemental analysis study suggest [ML2(H2O)2] stoichiometry, here M=Co(II), Ni(II) and Cu(II), L=deprotonated ligand. The obtained IR data supports the binding of metal ion to Schiff base. Thermal study suggests the presence of coordinated water molecules. Electronic spectral results reveal six coordinated geometry for the synthesized metal complexes. The Schiff bases and their metal complexes were evaluated for antibacterial (Pseudomonas aureginosa and Proteus mirabilis), antifungal (Aspergillus niger and Rhizopus oryzae), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activities. PMID:26874303

  4. Copper Chelation in Alzheimer's Disease Protein

    Science.gov (United States)

    Rose, Frisco; Hodak, Miroslav; Bernholc, Jerry

    2013-03-01

    Alzheimer's disease (AD) is a neurodegenerative disorder affecting millions of people in the U.S. AD is primarily characterized at the cellular level by densely tangled fibrils of amyloid- β protein. These protein clusters have been found in association with elevated levels of multiple transition metals, with copper being the most egregious. Interestingly, metal chelation has shown promise in attenuating the symptoms of AD in recent clinical studies. We investigate this process by constructing an atomistic model of the amyloid- β-copper complex and profile the energetic viability in each of its subsequent disassociation stages. Our results indicate that five energetic barriers must be overcome for full metal chelation. The energy barriers are biologically viable in the presence water mediated bond and proton transfer between the metal and the protein. We model the chelation reaction using a consecutive path nudged elastic band method implemented in our ab initio real-space multi-grid code to obtain a viable sequence. This reaction model details a physically consistent explanation of the chelation process that could lead to the discovery of more effective chelation agents in the treatment of AD.

  5. Design, synthesis and characterization of new iron and aluminium chelating agents

    OpenAIRE

    Toso, Leonardo

    2014-01-01

    Chelation therapy is widely used for metal-unbalance related diseases, namely those due to disorders on metal metabolism, such as beta-thalassemia, hemochromatosis (Fe), and neurodegenerative diseases (Cu, Fe, Zn and Al). The study of metal chelators for clinical applications, either as chelating therapeutics able to target specific metal ions in the body, or as metal-carriers for therapeutic or imaging purposes, is a topical research area which faces up to urgent medical problems. Meta...

  6. REGIONAL SIDEROSIS: A NEW CHALLENGE FOR IRON CHELATION THERAPY

    OpenAIRE

    ZviIoavCabantchik; ArnoldMunnich; MoussaB.Youdim; DavidDevos

    2013-01-01

    The traditional role of iron chelation therapy has been to reduce body iron burden via chelation of excess metal from organs and fluids and its excretion via biliary-fecal and/or urinary routes. In their present use for hemosiderosis, chelation regimens might not be suitable for treating disorders of iron maldistribution, as those are characterized by toxic islands of siderosis appearing in a background of normal or subnormal iron levels (e.g. sideroblastic anemias, neuro- and cardio-siderosi...

  7. Cinnamoylacetanilides and Their Metal Chelates

    Institute of Scientific and Technical Information of China (English)

    UMMATHUR Muhammed Basheer; KRISHNANKUTTY Krishnannair

    2008-01-01

    A new series of β-ketoanilides, in which the keto group attached to an olefinic linkage, have been synthesized by the reaction of acetoacetanilide with p-substituted benzaldehydes (4-methoxybenzaldehyde, 4-ethoxybenzaldehyde, 4-dimethylaminobenzaldehyde and 4-nitrobenzaldehyde) under specified conditions. The existence of these β-ketoanilides predominantly in the intramolecularly hydrogen bonded enol forms has been well demonstrated from their IR, 1H NMR and mass spectral data. Details on the formation of [ML2] complexes of these compounds with Ni(Ⅱ), Cu(Ⅱ) and Zn(Ⅱ) and their nature of bonding were discussed on the basis of analytical, IR, 1H NMR and mass spectral data.

  8. Effect of the nature of the stationary phase on the retention of metal chelates with 2(2-thiazolylazo)-5-diethylaminophenoly in high-performance liquid chromatography

    International Nuclear Information System (INIS)

    The retention of 2-(2-thiazolylazo)5-diethylaminophenol and its chelates with Co(2), Ni(2), Cu(2), Pd(2), Rh(3), Ru(4) on several stationary phases with different bonded hydrocarbon radicals (C2, C8 C18) was studied. The effect of mobile phase modifiers quaternary ammonium bromides was examined. Refs. 13, figs. 5, tabs. 2

  9. Light-Induced Copper(II) Coordination by a Bicyclic Tetraaza Chelator through a Ligand-to-Metal Charge-Transfer Reaction

    DEFF Research Database (Denmark)

    Holm-Jørgensen, Jacob Rørdam; Jensen, Mikael; Bjerrum, Morten J.

    2011-01-01

    To enable utilization of the broad potential of copper isotopes in nuclear medicine, rapid and robust chelation of the copper is required. Bowl adamanzanes (bicyclic tetraaza ligands) can form kinetically stable copper complexes, but they are usually formed at low rates unless high pH values and...

  10. Lanthanon chelates of monoprotic tridentate schiff base

    International Nuclear Information System (INIS)

    3-(N-thiophene-2-aldimino)propanoic acid (HTP), and its lanthanon chelates were synthesised and studied by physico-chemical techniques. Irving-Rossotti method was followed to determine the dissociation constants of the ligand and formation constants of its lanthanon chelates in aqueous medium (ionic strength μ = 0.01, 0.05 and 0.1 M NaClO4) at 25 0C, 35 0C and 45 0C. Solid lanthanon chelates were characterised by molecular mass, elemental analyses, conductance, magnetic, thermal and spectral analyses and were assigned 1 : 3 (metal-ligand) stoichiometry in which the lanthanon shows nine coordination numbers. Covalent nature of metal-ligand bond was found to increase with increase in atomic number of central lanthanide ion. (author)

  11. Chelation Treatment for Autism Spectrum Disorders: A Systematic Review

    Science.gov (United States)

    Davis, Tonya N.; O'Reilly, Mark; Kang, Soyeon; Lang, Russell; Rispoli, Mandy; Sigafoos, Jeff; Lancioni, Giulio; Copeland, Daelynn; Attai, Shanna; Mulloy, Austin

    2013-01-01

    Chelation treatment is used to eliminate specific metals from the body, such as mercury. It has been hypothesized that mercury poisoning may be a factor in autism and data suggest that perhaps 7% of individuals with autism spectrum disorder (ASD) have received chelation treatment. It would therefore seem timely to review studies investigating the…

  12. Macrocyclic Chelator Assembled RGD Multimers for Tumor Targeting

    OpenAIRE

    Zhang, Xiaofen; Liu, Hongguang; Miao, Zheng; Kimura, Richard; Fan, Feiyue; Cheng, Zhen

    2011-01-01

    Macrocyclic chelators have been extensively used for complexation of metal ions. A widely used chelator, DOTA, has been explored as a molecular platform to assemble multiple bioactive peptides in this paper. The multivalent DOTA-peptide bioconjugates demonstrate promising tumor targeting ability.

  13. Synthesis, metal complexation and biological evaluation of a novel semi-rigid bifunctional chelating agent for 99mTc labelling

    OpenAIRE

    Le Gal, Julien; Michaud, Sandra; Gressier, Marie; Coulais, Yvon; Benoist, Eric

    2006-01-01

    A novel bifunctional chelating agent bearing an aromatic ring has been synthesised and characterised. This ligand formed well-defined oxorhenium complexes. The analogous 99mTcO-complex was obtained in an excellent yield with high radiochemical purity (>95%). The biodistribution of the 99mTo-complex after intravenous injection studied in normal rats showed that the activity was excreted mainly via renal-urinary pathway indicating its use for labelling peptides with 99mTc.

  14. EDTA Chelation Therapy, Without Added Vitamin C, Decreases Oxidative DNA Damage and Lipid Peroxidation

    Science.gov (United States)

    Chelation therapy is thought to not only remove contaminating metals, but also to decrease free radical production. However, in standard EDTA chelation therapy high doses of vitamin C with potential prooxidant effects are often added to the chelation solution. We demonstrated previously that the in...

  15. Conjugates of monoclonal antibodies and chelating polymers

    International Nuclear Information System (INIS)

    The primary purpose of protein modification with chelating polymers is to prepare monoclonal antibodies labeled with heavy metal isotopes (alpha-, beta-, and gamma-emitting metal and paramagnetic ions for NMR tomography). Conventional binding of metals to proteins via chelating agents directly coupled to proteins does not permit binding of a large number of metal atoms per protein molecule without causing alterations in the specific properties of the protein molecules. On the other hand, metal ion binding to proteins via intermediate chelating polymers should permit binding of several dozens of the metal atoms per protein molecule without affect the specific properties adversely. Moreover, the biodistribution and clearance rates can be regulated by varying the polymer properties. Modified antibodies may be used successfully in nuclear and NMR diagnostic applications and in radiotherapy. Possible applications of this approach shall be demonstrated with monoclonal antibody R11D10 for visualization of acute myocardial infarction. Use of this modification with other monoclonal antibodies is also discussed. The chemistry of protein modification with these polymers is presented

  16. Comments on chelation therapy

    International Nuclear Information System (INIS)

    The primary purpose of actinide chelation is to decrease the risk from radiation-induced cancer. While occupational exposures in the past have mainly involved low specific activity 239Pu, future exposures will increasingly involve high specific activity plutonium, americium, and curium - all of which clear more rapidly from the lung. This will tend to shift the cancer risk from lung to bone and liver. Although therapy with Ca- or Zn-DTPA rapidly removes 241Am from the canine, the sub-human primate, and the human liver, improved methods for removal from bone and lung are needed. DTPA can remove 241Am more easily from the growing skeleton of a child than from the mature skeleton of an adult. Investigators at Karlsruhe are developing chelation agents for oral administration and are investigating the reduction in local dose to bone resulting from chelation therapy

  17. On-column tryptic mapping of proteins using metal-ion-chelated magnetic silica microspheres by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Li, Yan; Yan, Bo; Xu, Xiuqing; Deng, Chunhui; Yang, Pengyuan; Shen, Xizhong; Zhang, Xiangmin

    2007-01-01

    Peptide mapping analysis, utilizing an easily replaceable and regenerable on-column enzymatic microreactor with metal-ion-chelated adsorption of enzyme on magnetic silica microspheres, combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), was developed. Firstly, magnetic microspheres of small size and strong magnetism were prepared through solvothermal reaction. Thereafter, by introducing tetraethyl orthosilicate (TEOS), magnetic silica (MS) microspheres were formed. Trypsin could then be immobilized onto the MS microspheres based on the Lewis acid-base interaction through the divalent cation chelators such as iminodiacetic acid (IDA), which was chemically bound to the microspheres through the introduction of glycidoxypropyltrimethoxysilane (GLYMO). The trypsin-immobilized MS microspheres were then locally packed into the capillary by the application of a strong magnetic field using a magnet. The performance of the method was exemplified with digestion of bovine serum albumin for 5 min at 50 degrees C and the result was comparable to the 12 h in-solution digestion. The ability of regeneration of the prepared on-column microreactor and good reproducibility of microreactor before and after regeneration were also demonstrated. PMID:17577873

  18. The rapid separation of trace metals from neutron-activated saline matrices by chelation on a poly-5-vinyl-8-hydroxyquinoline column

    International Nuclear Information System (INIS)

    Instrumental neutron activation analysis of biological and environmental samples suffers from interferences caused by high salt concentrations. Poly-5-vinyl-8-hydroxyquinoline coated on controlled pore diameter glass beads is suggested as a chelating column for the rapid removal of aluminum, vanadium, copper and manganese from neutron-activated sea water samples. Separation from bulk elements is satisfactory at flow rates of 20 ml min-1. With addition of carriers and with chemical yield determinations, relative standard deviations of 2--10% can be achieved for spike concentrations of 0.1 μg Mn ml-1, 0.3 μg V ml-1, 20 μg V ml-1 and 1.0 μg Cu ml-1

  19. Mixed ligand chelate therapy for plutonium and toxic metals from energy power production. Progress report, October 15, 1978-October 14, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, J.

    1979-07-12

    It is shown that a mixed ligand chelate (MLC) is superior to that of the primary chelate alone for the decorporation of monomeric plutonium. Thus, EDTA plus Tiron reduces the level of Pu in the skeleton to about 40% less than that of EDTA alone when treatment was begun two hrs post /sup 239/Pu. However, DTPA alone was still superior to EDTA/Tiron under the given experimental conditions. However, this appears to be due to the rapid metabolic destruction of secondary chelants such as Tiron and similar bi-dentate derivatives of catechol and salicylates. Investigations are under way to improve such MLC's by the use of metabolic inhibitors to increase the plasma concentrations and residence times of the secondary chelants. In addition, MLC's consisting of metabolically stable chelants are undergoing testing. Therapy of cadmium poisoned mice by single and mixed chelants is also under study. A molar ratio of EDTA to Cd of 1.6 reduces the mortality by half of female mice given 5 min (i.p.) post supralethal doses of CdCl/sub 2/, while a molar ratio of 4.7 for 2, 3-dimercaptopropanol-1-sulfonate (DMPS) is required. No protection is observed with penicillamine (PA) or salicylates (SA) alone. However, combinations of EDTA with both PA and DMPS or SA and DMPS afford protection under conditions (30 min post Cd) where the individual chelants are ineffective. Automated potentiometric titrations are utilized to detect MLC formation and to evaluate their stability. The titration data are used as a screening procedure to ascertain whether a given chelant combination is worth testing in vivo.

  20. Mixed ligand chelate therapy for plutonium and toxic metals from energy power production. Progress report, October 15, 1978-October 14, 1979

    International Nuclear Information System (INIS)

    It is shown that a mixed ligand chelate (MLC) is superior to that of the primary chelate alone for the decorporation of monomeric plutonium. Thus, EDTA plus Tiron reduces the level of Pu in the skeleton to about 40% less than that of EDTA alone when treatment was begun two hrs post 239Pu. However, DTPA alone was still superior to EDTA/Tiron under the given experimental conditions. However, this appears to be due to the rapid metabolic destruction of secondary chelants such as Tiron and similar bi-dentate derivatives of catechol and salicylates. Investigations are under way to improve such MLC's by the use of metabolic inhibitors to increase the plasma concentrations and residence times of the secondary chelants. In addition, MLC's consisting of metabolically stable chelants are undergoing testing. Therapy of cadmium poisoned mice by single and mixed chelants is also under study. A molar ratio of EDTA to Cd of 1.6 reduces the mortality by half of female mice given 5 min (i.p.) post supralethal doses of CdCl2, while a molar ratio of 4.7 for 2, 3-dimercaptopropanol-1-sulfonate (DMPS) is required. No protection is observed with penicillamine (PA) or salicylates (SA) alone. However, combinations of EDTA with both PA and DMPS or SA and DMPS afford protection under conditions (30 min post Cd) where the individual chelants are ineffective. Automated potentiometric titrations are utilized to detect MLC formation and to evaluate their stability. The titration data are used as a screening procedure to ascertain whether a given chelant combination is worth testing in vivo

  1. Adsorptive separation of rare earths by using chelating chitosan

    International Nuclear Information System (INIS)

    Two kinds of chelating chitosan were prepared by chemically modifying chitosan with functional groups of EDTA or DTPA, abbreviated as EDTA- and DTPA-chitosan hereafter, respectively, to investigate the adsorption behaviour for rare earths the mutual separation of which is the most difficult among metal ions on these chelating chitosan from dilute hydrochloric or sulfuric acid solution. The plots of the distribution ratio of a series of rare earths against equilibrium pH lay on different straight lines with slope of 3 corresponding to each earth for both of two chelating chitosan, suggesting that 3 hydrogen ions are released for the adsorption of unit ion of each rare earth by chelate formation with the functional group of EDTA or DTPA and that mutual adsorptive separation between adjacent rare earth is possible with these chelating chitosan. Apparent equilibrium constants of the adsorption were evaluated from the intercepts of these straight lines with the ordinate for each rare earth and for both chelating chitosan. It was found that the equilibrium constants of adsorption on EDTA- or DTPA-chitosan are quite analogous to those of chelate formation with EDTA or DTPA themselves, suggesting that chelating characteristics of these complexones is still maintained after their immobilization on polymer matrices of chitosan. (author)

  2. Federal Regulation of Unapproved Chelation Products

    OpenAIRE

    Lee, Charles E.

    2013-01-01

    Chelation products can be helpful in the treatment of metal poisoning. However, many unapproved products with unproven effectiveness and safety are marketed to consumers, frequently via the internet. This paper describes the primary responsibility of the Health Fraud and Consumer Outreach Branch of the United States Food and Drug Administration to identify and address health fraud products. Efforts to prevent direct and indirect hazards to the population’s health through regulatory actions ar...

  3. SYNTHESIS, CHARACTERIZATION AND ANTIFUNGAL ACTIVITY OF 2-[(8-HYDROXYQUINOLINYL-5-AMINOMETHYL]-3-(4-CHLOROPHENYL-6-BROMO-3(H-QUINAZOLIN-4-ONE LIGAND AND ITS TRANSITION METAL CHELATES

    Directory of Open Access Journals (Sweden)

    R. T. Vashi

    2015-07-01

    Full Text Available Synthesis and characterization of 2-[(8-hydroxyquinolinyl-5-aminomethyl]-3-(4-chlorophenyl-6-Bromo-3(H-quinazolin-4-one ligand called HAMQ (HL10 was studied. To prepare this ligand anthranilic acid was converted into 5-bromo–N-Chloroacetyl anthranilic acid then into 2-[(8-hydroxyquinolinyl -5-aminomethyl] -3-(4-chrolophenyl -6-bromo- 3(H-quinazolin-4-one. This compound was prepared by condensation with 5-amino-8-hydroxyquinoline. New transition metal chelates of Cu2+,Ni2+, Zn2+, Mn2+ and Co2+ of this ligand HAMQ  were  prepared and  characterized  by reflectance, 1H-NMR as well as IR spectroscopy, elemental analysis molar conductance and magnetic measurements. The stoichiometry of the complexes has been found to be 1: 2 (Metal: ligand. The data suggested an octahedral geometry around Co2+, Ni2+ and Mn2+ complexes, a distorted octahedral geometry around Cu2+ and a tetrahedral geometry around Zn2+ have been proposed. The metal complexes were screened for the antifungal activity.

  4. SYNTHESIS, CHARACTERIZATION AND ANTIFUNGAL ACTIVITY OF 2-[(8-HYDROXYQUINOLINYL-5-AMINOMETHYL]-3-(4-CHLOROPHENYL-6-BROMO-3(H-QUINAZOLIN-4-ONE LIGAND AND ITS TRANSITION METAL CHELATES

    Directory of Open Access Journals (Sweden)

    R. T. Vashi

    2013-12-01

    Full Text Available Synthesis and characterization of 2-[(8-hydroxyquinolinyl-5-aminomethyl]-3-(4-chlorophenyl-6-Bromo-3(H-quinazolin-4-one ligand called HAMQ (HL10 was studied. To prepare this ligand anthranilic acid was converted into 5-bromo–N-Chloroacetyl anthranilic acid then into 2-[(8-hydroxyquinolinyl -5-aminomethyl] -3-(4-chrolophenyl -6-bromo- 3(H-quinazolin-4-one. This compound was prepared by condensation with 5-amino-8-hydroxyquinoline. New transition metal chelates of Cu2+, Ni2+, Zn2+, Mn2+ and Co2+ of this ligand HAMQ were prepared and characterized by reflectance, 1H-NMR as well as IR spectroscopy, elemental analysis molar conductance and magnetic measurements. The stoichiometry of the complexes has been found to be 1: 2 (Metal: ligand. The data suggested an octahedral geometry around Co2+, Ni2+ and Mn2+ complexes, a distorted octahedral geometry around Cu2+ and a tetrahedral geometry around Zn2+ have been proposed. The metal complexes were screened for the antifungal activity.

  5. Solubilidade, fracionamento e fitoextração de metais pesados após aplicação de agentes quelantes Solubility, phytoextraction and fractionation of heavy metals as a function of chelating agents applied to soil

    Directory of Open Access Journals (Sweden)

    Évio Eduardo Chaves de Melo

    2006-12-01

    Full Text Available A baixa biodegrabilidade de quelantes sintéticos usados para induzir a fitoextração resulta em alto risco ambiental pela possibilidade de lixiviação de metais pesados. Agentes quelantes naturais, mais rapidamente degradados no solo, podem ser uma alternativa para os quelantes sintéticos. O objetivo deste trabalho foi comparar a performance de ácidos orgânicos naturais (gálico, cítrico e oxálico com ácidos sintéticos (EDTA, DTPA e NTA na fitoextração induzida de metais. O solo foi contaminado com 500, 300 e 200 mg kg-1 de Pb, Zn e Cu, respectivamente, e cultivado com milho (Zea mays e mucuna preta (Stizolobium aterrimum. Os agentes quelantes, na dose de 10 mmol kg-1, foram aplicados no solo sete dias antes da coleta das plantas. Amostras do solo foram submetidas à extração com CaCl2 e fracionamento. Os teores dos metais na solução do solo foram também determinados. Os quelantes sintéticos EDTA, DTPA e NTA foram eficientes na solubilização dos metais pesados no solo. Dentre os ácidos orgânicos naturais, apenas o ácido cítrico foi eficiente na solubilização dos metais nas primeiras vinte e quatro horas após a sua aplicação. A distribuição dos metais entre as frações apresentou a seguinte ordem: Pb: matéria orgânica (MO > óxido de Fe amorfo (OxFeA > trocável (Tr > óxido de Fe cristalino (OxFeC; Cu: MO > Tr > OxFeC > OxFeA; e Zn: MO > Tr > OxFeC > OxFeA. De modo geral, a adição dos quelantes sintéticos provocou aumento nos teores trocáveis de Pb e Cu e redução nos teores de Pb, Cu e Zn nas frações óxidos de Fe amorfo e cristalino. O extrator CaCl2 0,01 mol L-1 pode ser utilizado para predição da concentração de Pb, Cu e Zn na solução do solo.The low biodegradability of synthetic chelating agents used for phytoextraction poses a great environmental risk due to the potential for metal leaching. Natural chelating agents can be an alternative to synthetic chelates due to their rapid biodegrability

  6. Selectivity in extraction of copper and indium with chelate extractants

    International Nuclear Information System (INIS)

    Simultaneous extraction of copper and indium with chelate extractants (LIX84 and D2E11PA) was described. Stechiometry of metal-organic complexes examined using the method of equimolar ratios resulted in CuR2 and InR3 forms of hydrophobic extracting species. A linear correlation was obtained between logarithm of distribution coefficients and chelate agents and pH, respectively. Selectivity is generally higher with higher concentrations of chelate agents in the organic phase, and is decreased with increase of concentration of hydrogen ions in feeding phase. (Original)

  7. Complex forming competition and in-vitro toxicity studies on the applicability of di-2-pyridylketone-4,4,-dimethyl-3-thiosemicarbazone (Dp44mT) as a metal chelator.

    Science.gov (United States)

    Gaál, Anikó; Orgován, Gábor; Polgári, Zsófia; Réti, Andrea; Mihucz, Victor G; Bősze, Szilvia; Szoboszlai, Norbert; Streli, Christina

    2014-01-01

    Di-2-pyridylketone-4,4,-dimethyl-3-thiosemicarbazone (Dp44mT) is a potential candidate in chelation therapy as an iron chelator. This study showed that a combined treatment with 2μM easily available Fe(II), Cu(II) and Zn(II) each and 5μM Dp44mT on eight different cancer cell lines resulted in a 10-40-fold increase in the intracellular Cu content compared to control samples. The uptake of Cu and Cu-dependent cytotoxicity strictly depend on the Cu concentration of the culture medium. Even as low concentration of Dp44mT as 0.1μM can transport high amounts of copper inside the cells. The Cu accumulation and toxicity through Dp44mT can hardly be influenced by Fe. Copper uptake and toxicity triggered by 2μM extracellular Cu(II) and 5μM Dp44mT could not be influenced by Fe(II) extracellular concentrations even 50-times higher than that of Cu(II). A 50-times higher Co(II) extracellular concentration hindered the Cu(II) uptake almost completely and a 10-times higher Co(II) concentration already decreased the Dp44mT-mediated Cu toxicity. Conditional complex stability constant determinations for Dp44mT with Cu(II), Co(II), Fe(II), Ni(II) and Zn(II) revealed that the metal-to-ligand ratio is 1:1 in [Cu(II)Dp44mT] complex, while for Co(II), Fe(II) and Ni(II) is 1:2. The highest stability constant was obtained for Cu(II) (lg β=7.08±0.05) and Co(II) (lg β2=12.47±0.07). According to our results, Dp44mT in combination with Cu is highly toxic in vitro. Therefore, the use of Dp44mT as an iron chelator is limited if biologically available Cu is also present even at low concentrations. PMID:24176919

  8. THE STUDIES ON CHELATING FIBER V.ADSORPTION BEHAVIOR OF Au3+ ONTO CHELATING FIBER CONTAINING AMIDOXIME GROUPS

    Institute of Scientific and Technical Information of China (English)

    LINWeiping; LUYun; 等

    1992-01-01

    The adsorption behavior of ionic gold onto chelating fiber containing amidoxime groups was investigated. The chelating fiber presents high adsorption capacity for ionic gold Au3+(up to 626mg/g,when the content of amidoxime group reaches 7.59mmol/g),and possesses the ability to reduce the Au3+ into metallic gold,In the redox process,the amidoxime group is oxidized into carboxyl group.

  9. Flame Atomic Absorption Spectrometric Determination of Trace Metal Ions in Environmental and Biological Samples After Preconcentration on a Newly Developed Amberlite XAD-16 Chelating Resin Containing p-Aminobenzene Sulfonic Acid.

    Science.gov (United States)

    Islam, Aminul; Ahmad, Akil; Laskar, Mohammad Asaduddin

    2015-01-01

    Amberlite® XAD-16 was functionalized with p-aminobenzene sulfonic acid via an azo spacer in order to prepare a new chelating resin, which was then characterized by water regain value, hydrogen ion capacity, elemental analyses, and IR spectral and thermal studies. The maximum uptake of Cu(II), Ni(II), Zn(II), Co(II), Cr(III), Fe(III), and Pb(II) ions was observed in the pH range 4.0-6.0 with the corresponding half-loading times of 6.5, 7.0, 8.0, 9.0, 11.0, 8.5, and 16.5 min. The sorption data followed Langmuir isotherms and a pseudo-second-order model. Thermodynamic quantities, ΔH and ΔS, based on the variation of the distribution coefficient with temperature were also evaluated. High preconcentration factors of 60-100 up to a low preconcentration limit of 4.0-6.6 μg/L have been achieved for the metal ions. The validity of the method was checked by analyzing standard reference materials and recoveries of trace metals after spiking. The analytical applications of the method were explored by analyzing natural water, mango pulp, mint leaves, and fish. PMID:25857893

  10. Synthesis and characterization of ligational behavior of curcumin drug towards some transition metal ions: Chelation effect on their thermal stability and biological activity

    Science.gov (United States)

    Refat, Moamen S.

    2013-03-01

    Complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with curcumin ligand as antitumor activity were synthesized and characterized by elemental analysis, conductometry, magnetic susceptibility, UV-Vis, IR, Raman, ESR, 1H-NMR spectroscopy, X-ray diffraction analysis of powdered samples and thermal analysis, and screened for antimicrobial activity. The IR spectral data suggested that the ligand behaves as a monobasic bidentate ligand towards the central metal ion with an oxygen's donor atoms sequence of both sbnd OH and Cdbnd O groups under keto-enol structure. From the microanalytical data, the stoichiometry of the complexes 1:2 (metal:ligand) was found. The ligand and their metal complexes were screened for antibacterial activity against Escherichia Coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa and fungicidal activity against Aspergillus flavus and Candida albicans.

  11. Extraction of Heavy Metals from Sludge Using Biodegradable Chelating Agent N,N-bis(carboxymethyl) Glutamic Acid Tetrasodium%生物可降解螯合剂谷氨酸 N,N -二乙酸四钠对污泥中重金属萃取效率的研究

    Institute of Scientific and Technical Information of China (English)

    吴青; 崔延瑞; 汤晓晓; 杨慧娟; 孙剑辉

    2015-01-01

    N, N-bis ( carboxymethyl) glutamic acid tetrasodium ( GLDA), a novel biodegradable and green chelating agent, has excellent metal chelating ability. Batch experiment was conducted to study the extraction process of Cd, Ni, Cu and Zn in industrial sludge using GLDA. The effects of contact time, pH of the system, content of chelating agent were investigated, and the forms of heavy metals in sludge pre- and post-extraction using the modified BCR sequential extraction procedure were studied. The results showed that GLDA was effective for cadmium extraction in sludge. Several heavy metals could be effectively extracted under the condition of pH 4 and molar ratio of chelating agent to total heavy metal 3: 1. Residual fraction took the largest fraction in Zn, which caused the low extraction efficiency of this metal. Chelating properties were related not only to contact time, pH, chelating agent’s concentration, and stability constant but also to species distribution of metals.%谷氨酸 N,N -二乙酸四钠(GLDA)具有较强金属螯合能力,是新一代生物可降解绿色螯合剂。通过分批提取实验对GLDA 去除工业污泥中 Cd、 Ni、 Cu、 Zn 的萃取过程进行研究,考察了萃取时间、萃取体系 pH 值、螯合剂用量等因素对重金属萃取效果的影响,并采用修正的 BCR 连续提取法分析萃取前后污泥中重金属的形态。结果表明, GLDA 对污泥中 Cd 具有良好的去除效果;体系在 pH =4,螯合剂与重金属总量摩尔比为3:1的条件下,多种重金属取得最佳萃取效果; Zn 主要以残渣态存在,导致该金属萃取率低;螯合能力不仅与萃取时间,萃取体系 pH 值,螯合剂用量,螯合常数等因素有关,而且还与金属的形态分布有关。

  12. Effects of macromolecular chelators on intestinal cadmium absorption in mice

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, O.; Nielsen, J.B.; Bulman, R.A.

    1989-01-01

    Suppression of absorption by macromolecular chelators have been sucessful with several metals. In this paper a series of immobilized chelators ranging from DTPA to S-containing soft bases have been synthetized and investigated for ability to suppress intestinal uptake of /sup 109/Cd/sup 2+/ in mice. Dextran-O-ethyl-mercaptan, xanthates derived from polysaccharides and polyvinyl alcohol, dithiocarbamates of polyethylene imine and aminoethyl cellulose, and DTPA immobilized on aminopropyl silica were all ineffective. DTPA immobilized on aminoethyl cellulose even enhanced the intestinal uptake. The macromolecular chelators were without extensive effect on organ distribution of absorbed cadmium, except for dithiocarbamate immobilized on polyethylene imine, which enhanced the deposition of cadmium in several organs including the brain. Although the results are discouragign, they indicate that desing and synthesis of immobilized vicinal dithio compounds may represent an avenue for development of non-absorbable chelators with high affinity for cadmium.

  13. Comparing potential copper chelation mechanisms in Parkinson's disease protein

    Science.gov (United States)

    Rose, Frisco; Hodak, Miroslav; Bernholc, Jerry

    2011-03-01

    We have implemented the nudged elastic band (NEB) as a guided dynamics framework for our real-space multigrid method of DFT-based quantum simulations. This highly parallel approach resolves a minimum energy pathway (MEP) on the energy hypersurface by relaxing intermediates in a chain-of-states. As an initial application we present an investigation of chelating agents acting on copper ion bound to α -synuclein, whose misfolding is implicated in Parkinson's disease (PD). Copper ions are known to act as highly effective misfolding agents in a-synuclein and are thus an important target in understanding PD. Furthermore, chelation therapy has shown promise in the treatment of Alzheimer's and other neuro-degenerative diseases with similar metal-correlated pathologies. At present, our candidate chelating agents include nicotine, curcumin and clioquinol. We examine their MEP activation barriers in the context of a PD onset mechanism to assess the viability of various chelators for PD remediation.

  14. Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

    International Nuclear Information System (INIS)

    The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, (1H, and 13C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented

  15. Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

    Energy Technology Data Exchange (ETDEWEB)

    Fatimah, Soja Siti, E-mail: soja-sf@upi.edu [Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi No. 229, Bandung 40154 (Indonesia); Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jl. Raya Bandung-Sumedang, Km. 21, Jatinangor (Indonesia); Bahti, Husein H.; Hastiawan, Iwan [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jl. Raya Bandung-Sumedang, Km. 21, Jatinangor (Indonesia); Permanasari, Anna [Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi No. 229, Bandung 40154 (Indonesia)

    2016-02-08

    The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, ({sup 1}H, and {sup 13}C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.

  16. Biochelators as an alternative to EDTA and other synthetic chelators for the phytoextraction of heavy metals (Cu, Cd, Pb) from soil

    OpenAIRE

    Evangelou, Michael Wassilios Hermann

    2007-01-01

    Heavy metal pollution of soil is a global problem. Diffuse contamination of large areas causes particular difficulties, since most classical engineering technology directed at soil decontamination is associated with a loss of land, and is usually costly. For arable land, in which low to medium level contamination threatens soil fertility and human health in the long term, gentle remediation techniques are required which not only reduce toxicological risks, but also restore soil fertility. In ...

  17. Chelation Ion Chromatography on 1-(2-Pyridylazo-2-naphthol Sorbed Stannic Silicate: Selective Separation of Cd2+, Hg2+ and Pb2+ from some Transition Metal Ions

    Directory of Open Access Journals (Sweden)

    Rawat, J.P.

    2011-12-01

    Full Text Available Selective separation of three of the most toxic metal ions Cd2+, Hg2+ and Pb2+ has been achieved on a column packed with 1-(2-pyridylazo-2-naphthol (PAN sorbed stannic silicate using nitric acid solution of pH 1 and 6 as eluents. Adsorption behavior of several metal ions like Al3+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ on PAN sorbed stannic silicate from aqueous solution at different pH (from 1 to 6 was studied to calculate their distribution coefficients. In addition to the selective separation of Cd2+, Hg2+ and Pb2+ several binary separations of metal ions e. g., Hg2+ - Al3+, Pb2+ - Cr3+, Cd2+ - Cr3+ and Hg2+ - Cr3+ using aqueous solutions of pH 6 and pH 1 aseluents have been successfully achieved on PAN sorbed stannic silicate.

  18. The use of new modified poly(acrylamide chelating resin with pendent benzothiazole groups containing donor atoms in the removal of heavy metal ions from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Semmedu Selvaraj Kalaivani

    2014-03-01

    Full Text Available The adsorption studies of poly(6-(ethoxybenzothiazole acrylamide (PEBTA, for Cu(II and Zn(II metal ions removal from an aqueous solution have been investigated, as a function of solution pH, adsorbent dose, contact time, initial metal ion concentration and temperature. The chemical and structural characteristics of the adsorbent were determined by the FT-IR, 1H-NMR, TGA, SEM, and EDAX analysis. The maximum adsorption capacities of the adsorbent for Cu(II and Zn(II ions, as calculated from the Langmuir isotherm model, were 273.5 and 216.4 mg/g, respectively. The adsorption kinetic studies show that the adsorption of Cu(II and Zn(II ions onto PEBTA follows the pseudo second order kinetic model. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were also evaluated, and it has been found that the adsorption process is feasible, spontaneous and exothermic in nature. Desorption studies were carried out using 0.3 N HCl, and it revealed that the adsorbed Cu(II and Zn(II ions can be easily removed. The adsorption–desorption process is reversible, and this indicates that PEBTA is an effective adsorbent for the removal of heavy metal ions from an aqueous medium.

  19. Structure of the first representative of Pfam family PF04016 (DUF364) reveals enolase and Rossmann-like folds that combine to form a unique active site with a possible role in heavy-metal chelation

    International Nuclear Information System (INIS)

    The crystal structure of the first representative of DUF364 family reveals a combination of enolase N-terminal-like and C-terminal Rossmann-like folds. Analysis of the interdomain cleft combined with sequence and genome context conservation among homologs, suggests a unique catalytic site likely involved in the synthesis of a flavin or pterin derivative. The crystal structure of Dhaf4260 from Desulfitobacterium hafniense DCB-2 was determined by single-wavelength anomalous diffraction (SAD) to a resolution of 2.01 Å using the semi-automated high-throughput pipeline of the Joint Center for Structural Genomics (JCSG) as part of the NIGMS Protein Structure Initiative (PSI). This protein structure is the first representative of the PF04016 (DUF364) Pfam family and reveals a novel combination of two well known domains (an enolase N-terminal-like fold followed by a Rossmann-like domain). Structural and bioinformatic analyses reveal partial similarities to Rossmann-like methyltransferases, with residues from the enolase-like fold combining to form a unique active site that is likely to be involved in the condensation or hydrolysis of molecules implicated in the synthesis of flavins, pterins or other siderophores. The genome context of Dhaf4260 and homologs additionally supports a role in heavy-metal chelation

  20. Bifunctional chelating agent for the design and development of site specific radiopharmaceuticals and biomolecule conjugation strategy

    Science.gov (United States)

    Katti, Kattesh V.; Prabhu, Kandikere R.; Gali, Hariprasad; Pillarsetty, Nagavara Kishore; Volkert, Wynn A.

    2003-10-21

    There is provided a method of labeling a biomolecule with a transition metal or radiometal in a site specific manner to produce a diagnostic or therapeutic pharmaceutical compound by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radio metal or a transition metal, and covalently linking the resulting metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. Also provided is a method of synthesizing the --PR.sub.2 containing biomolecules by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radiometal or a transition metal, and covalently linking the resulting radio metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. There is provided a therapeutic or diagnostic agent comprising a --PR.sub.2 containing biomolecule.

  1. Novel Lipid-Soluble Thiol-Redox Antioxidant and Heavy Metal Chelator, N,N′-bis(2-Mercaptoethyl)Isophthalamide (NBMI) and Phospholipase D-Specific Inhibitor, 5-Fluoro-2-Indolyl Des-Chlorohalopemide (FIPI) Attenuate Mercury-Induced Lipid Signaling Leading to Protection Against Cytotoxicity in Aortic Endothelial Cells

    OpenAIRE

    Secor, Jordan D.; Kotha, Sainath R.; Gurney, Travis O.; Patel, Rishi B.; Kefauver, Nicholas R.; Gupta, Niladri; Morris, Andrew J.; Haley, Boyd E.; Parinandi, Narasimham L.

    2011-01-01

    Here, we investigated thiol-redox-mediated phospholipase D (PLD) signaling as a mechanism of mercury cytotoxicity in mouse aortic endothelial cell (MAEC) in vitro model utilizing the novel lipid-soluble thiol-redox antioxidant and heavy metal chelator, N,N′-bis(2-mercaptoethyl)isophthalamide (NBMI) and the novel PLD-specific inhibitor, 5-fluoro-2-indolyl des-chlorohalopemide (FIPI). Our results demonstrated (i) mercury in the form of mercury(II) chloride, methylmercury, and thimerosal induced...

  2. The Scientific Basis for Chelation: Animal Studies and Lead Chelation

    OpenAIRE

    Smith, Donald; Strupp, Barbara J.

    2013-01-01

    This presentation summarizes several of the rodent and non-human studies that we have conducted to help inform the efficacy and clinical utility of succimer (meso-2,3-dimercaptosuccincinic acid) chelation treatment. We address the following questions: (1) What is the extent of body lead, and in particular brain lead reduction with chelation, and do reductions in blood lead accurately reflect reductions in brain lead? (2) Can succimer treatment alleviate the neurobehavioral impacts of lead poi...

  3. New chelation strategies for the uranyl ion

    International Nuclear Information System (INIS)

    Traditional approaches to the design of metal-ion-specific complexing agents have relied to a great extent on the creation of a ligand cavity of the appropriate size and coordination number to accommodate the targeted metal ion. Oxo-metal ions, such as uranyl, cannot be dealt with as spherically symmetric charged atoms and thus present both a special challenge and offer a unique advantage for specific chelation in solution. To maximize recognition of the anisotropic UO22+ ion, new tripodal hexadentate ligands have been prepared providing three carboxyl moieties each to act as a bidentate donor group. The novel ligand design concept, ligand syntheses, and thermodynamic results related to the uranyl complex characterization are presented

  4. The antibody-linked chelating polymers for nuclear therapy and diagnostics

    International Nuclear Information System (INIS)

    This review deals with the problem of protein modification with chelating polymers. The main purpose of this approach is the preparation of monoclonal antibodies labeled with heavy metal isotopes (α-, β-, and δ-emitting metals and metals used for NMR-tomography). Traditional binding of metals with proteins via chelating agents directly coupled to protein molecule does not allow binding a high number of metal atoms per single protein molecule and can also alter protein specific properties. At the same time, metal-to-protein binding via intermediate chelating polymer makes possible the binding of several dozen metal atoms per single protein without affecting its specific properties. Moreover, the variations in polymer properties and molecular weight allow controlled modified antibody biodistribution and clearance rate. Modified antibodies can be used successfully for nuclear and NMR diagnostics and for nuclear therapy. The following problems are discussed: the chemistry of the coupling of chelating groups to polymer backbone; the binding of chelating polymers to proteins, including monoclonal antibodies; the ability of chelating polymer-to-protein conjugates to bind heavy metals; the influence of the modification on protein conformation and specific properties; the behavior of metal-containing conjugates in vivo; the practical use of conjugates obtained for radioimmunoimaging, radioimmunotherapy, NMR-tomography, and in vitro immunoassays. Future prospects of the approach are also discussed.101 references

  5. New 111In labeling of IgG: 111In-oxine mediated chelation

    International Nuclear Information System (INIS)

    Current methods of 111In chelate conjugation labeling of antibodies expose the protein to pH 5-6 during 111In chelation. These conditions could be detrimental if the antibody is acid labile. We have successfully labeled human IgG via the cyclic anhydride of DPTA and 111In-oxyquinoline(oxine). Chelation was achieved at pH 6.9-8.4 and was complete within 1 min at room temperature. The chelation was sensitive to trace metal contamination on labware and in some reagents (including commercial 111In-oxine). (author)

  6. Synthesis of amidoxime chelating fiber and its adsorption properties for Cu(II) ion

    International Nuclear Information System (INIS)

    In order to obtain the chelating fiber for adsorbing metal ions in apple juice, the effect of different conditions on adsorption properties of chelating fiber for Cu(II) ion were discussed, such as pH and the time of ad- sorption. The isotherm of adsorption has bee confirmed. The desorption and its regeneration were simply discussed, too. The results showed that the chelating fiber had good kinetic property and the adsorbed equilibrium completed almost within 20-30 min. The adsorption properties was affected by the temperature and pH. The adsorption process fits the isothermal equation of Freundlich. The chelating fiber could be used repeatedly. (authors)

  7. Chemistry of carcinogenic metals.

    OpenAIRE

    Martell, A E

    1981-01-01

    The periodic distribution of known and suspected carcinogenic metal ions is described, and the chemical behavior of various types of metal ions is explained in terms of the general theory of hard and soft acids and bases. The chelate effect is elucidated, and the relatively high stability of metal chelates in very dilute solutions is discussed. The concepts employed for the chelate effect are extended to explain the high stabilities of macrocyclic and cryptate complexes. Procedures for the us...

  8. Oxidation of calprotectin by hypochlorous acid prevents chelation of essential metal ions and allows bacterial growth: Relevance to infections in cystic fibrosis.

    Science.gov (United States)

    Magon, Nicholas J; Turner, Rufus; Gearry, Richard B; Hampton, Mark B; Sly, Peter D; Kettle, Anthony J

    2015-09-01

    Calprotectin provides nutritional immunity by sequestering manganese and zinc ions. It is abundant in the lungs of patients with cystic fibrosis but fails to prevent their recurrent infections. Calprotectin is a major protein of neutrophils and composed of two monomers, S100A8 and S100A9. We show that the ability of calprotectin to limit growth of Staphylococcus aureus and Pseudomonas aeruginosa is exquisitely sensitive to oxidation by hypochlorous acid. The N-terminal cysteine residue on S100A9 was highly susceptible to oxidation which resulted in cross-linking of the protein monomers. The N-terminal methionine of S100A8 was also readily oxidized by hypochlorous acid, forming both the methionine sulfoxide and the unique product dehydromethionine. Isolated human neutrophils formed these modifications on calprotectin when their myeloperoxidase generated hypochlorous acid. Up to 90% of the N-terminal amine on S100A8 in bronchoalveolar lavage fluid from young children with cystic fibrosis was oxidized. Oxidized calprotectin was higher in children with cystic fibrosis compared to disease controls, and further elevated in those patients with infections. Our data suggest that oxidative stress associated with inflammation in cystic fibrosis will stop metal sequestration by calprotectin. Consequently, strategies aimed at blocking extracellular myeloperoxidase activity should enable calprotectin to provide nutritional immunity within the airways. PMID:26006104

  9. Overview of current chelation practices

    OpenAIRE

    Aydinok, Y.

    2011-01-01

    Deferoxamine (DFO) is reference standard therapy for transfusional iron overload since the 1980s. Although it is a highly effective iron chelator, the compliance problem to subcutaneous administration of DFO remains as the major problem. The oral chelator Deferiprone (DFP) has no marketing licence in North America, however, it has been licensed in India since 1994 and the European Union (EU) granted marketing approval for DFP in 1999, specifically for patients with thalassemia major when DFO ...

  10. Microwave Irradiation-Assisted Synthesis of a Novel Crown Ether Crosslinked Chitosan as a Chelating Agent for Heavy Metal Ions (M+n

    Directory of Open Access Journals (Sweden)

    Ibrahim A. Alsarra

    2010-09-01

    Full Text Available Microwave irradiation was used to obtain a di-Schiff base type crosslinked chitosan dibenzocrown ether (CCdBE via the reaction between the –NH2 and –CHO groups in chitosan and 4,4′-diformyldibenzo-18-c-6, respectively. The structure of the synthesized compound was characterized by elemental analysis, solid state 13C-NMR and FT-IR spectra analysis. The results showed that the mass fraction of nitrogen in the CCdBE derivative was much lower than those of chitosan. The FT-IR spectra of CCdBE revealed the expected chitosan-crown ether structure, as evidenced by the presence of the characteristic C=N and Ar peaks. The adsorption properties of CCdBE for Pd2+ and Hg2+ were investigated and the results demonstrated that the adsorbent has both desirable adsorption properties with a high particular adsorption selectivity for Hg2+ when in the presence of Pb2+ as well as selectivity coefficients for metal ions of KHg2+ /Pb2+ = 8.00 and KHg 2+/Pb2+ = 10.62 at pH values of 4 and 6, respectively. The reusability tests for CCdBE for Pb2+ adsorption showed that complete recovery of the ion was possible with CCdBE after 10-multiple reuses while CTS had no reusability at acidic solution because of its higher dissolution. The studied features of CCdBE suggested that the material could be considered as a new adsorbent. It is envisaged that the crosslinking of CTS into CCdBE would enhance practicality and effectiveness of adsorption in ion separation and removal procedures.

  11. Sequestration of zinc oxide by fimbrial designer chelators

    DEFF Research Database (Denmark)

    Kjærgaard, Kristian; Sørensen, Jack K; Schembri, Mark; Klemm, Per

    2000-01-01

    Type 1 fimbriae are surface organelles of Escherichia coli. By engineering a structural component of the fimbriae, FimH, to display a random peptide library, we were able to isolate metal-chelating bacteria. A library consisting of 4 x 10(7) independent clones was screened for binding to Zn...

  12. Development of a treatment process for the removal of heavy metals from raw water for drinking water supply using chelating ion exchange resins. Subproject 1. Final report; Entwicklung der Verfahrenstechnik zur Eliminierung von Schwermetallen aus Rohwaessern zur Trinkwassergewinnung mit chelatbildenden Kationenaustauscherharzen zur technischen Reife. Teilprojekt 1. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Overath, H.; Stetter, D.; Doerdelmann, O.

    2002-07-01

    Chelating cation exchange resins with iminodiacetic acid group (Lewatit TP 207 and Amberlite IRC 748) were tested for the removal of heavy metals in a drinking water treatment plant. The pilot scale filtration experiments were conducted by varying the operating conditions, such as flow rate and feed concentrations. Heavy metal concentrations (nickel, lead, cadmium, zinc) in the feed were adjusted between 20 and 200 {mu}g/L. Different methods for regeneration and conditioning of the resins were developed and investigated. Finally the ion exchange resins were tested according to German health regulations for ion exchangers in drinking water treatment. (orig.)

  13. Metal based pharmacologically active agents: Synthesis, structural characterization, molecular modeling, CT-DNA binding studies and in vitro antimicrobial screening of iron(II) bromosalicylidene amino acid chelates

    Science.gov (United States)

    Abdel-Rahman, Laila H.; El-Khatib, Rafat M.; Nassr, Lobna A. E.; Abu-Dief, Ahmed M.; Ismael, Mohamed; Seleem, Amin Abdou

    2014-01-01

    flavus and Trichotheium rosium. The results of these studies indicated that the metal complexes exhibit a stronger antibacterial and antifungal efficiency than their corresponding Schiff base amino acid ligands.

  14. Samarium-153 and lutetium-177 chelation properties of selected macrocyclic and acyclic ligands

    International Nuclear Information System (INIS)

    We describe a simple in vitro characterization of chelation that is useful when choosing an appropriate ligand-metal combination for clinical applications. These properties include the effect of concentration on chelation efficiency, time to maximum chelation, and stability in acidic and serum environments. The macrocyclic ligands nitro-DOTA and nitro-PADOTA, the acyclic ligands nitro-CHX-A-DTPA, nitro-MX-DTPA, DTPA, and a novel terpyridine ligand, TMT-amine, were evaluated as chelate complexes of both intermediate energy β-emitting lanthanides lutetium-177 and samarium-153. The data were compared to results obtained in a previously published study with yttrium-90. Acid lability, time to achieve maximum chelation, and stability in human serum are properties unique to each ligand-metal combination and should be evaluated prior to choosing an appropriate combination for therapeutic applications. Concentration dependence and duration of chelation are general properties of lanthanide and yttrium chelation that can be applied to an appropriate ligand-metal combination to achieve optimum chelation efficiencies

  15. Preparation and characterization of chitosan-grafted-poly(2-amino-4,5-pentamethylene-thiophene-3-carboxylic acid N'-acryloyl-hydrazide) chelating resin for removal of Cu(II), Co(II) and Ni(II) metal ions from aqueous solutions.

    Science.gov (United States)

    Bekheit, M M; Nawar, N; Addison, A W; Abdel-Latif, D A; Monier, M

    2011-05-01

    The graft copolymerization of ethylacrylate (EA) onto chitosan initiated by potassium persulphate and Mohr's salt combined redox initiator system in limited aqueous medium was carried out in heterogeneous media. Moreover, modification of the grafted chitosan was carried out by reaction of the ester group (-COOEt) with 2-amino-4,5-pentamethylene-thiophene-3-carboxylic acid hydrazide which eventually produce chitosan-grafted-poly(2-amino-4,5-pentamethylene-thiophene-3-carboxylic acid N'-acryloyl-hydrazide) (chitosan-g-ATAH) chelating resin. The application of the modified resin for metal ion uptake was studied using Cu(2+), Co(2+) and Ni(2+) ions. The modified chelating resins were characterized using FTIR spectroscopy, SEM and X-ray diffraction. PMID:21277322

  16. Regularities in aluminium and indium chemisorption on chelating polymeric sorbents

    International Nuclear Information System (INIS)

    Complexation properties of synthesized polymer chelate sorbents: substituted of polystyrene-azo-pyrocatechol are investigated and correlations between pK'OH of functional groups of sorbents as well as pH50 values of chelation and constants of stability (lgKstab) are established for studying regularities of effect of structure and acid-base properties of functional groups of sorbents on the parameters of Al3+ and In3+ chemical sorption. Established correlations make it possible to predict the physicochemical parameters of sorbents and sorption of metal ions with the aim of separation and concentration of aluminium and indium micro account from the objects of different origin

  17. Chelating agents to solubilize heavy metals from Oxisols contaminated by the addition of organic and inorganic residues Uso de quelantes na solubilização de metais pesados de Latossolos contaminados pela adição de resíduos orgânico e inorgânico

    Directory of Open Access Journals (Sweden)

    Aline Renée Coscione

    2009-02-01

    Full Text Available Phytoremediation is an attractive technique for soils contaminated with heavy metals, especially in conjunction with chelating agents to assist metal phytoextraction. Nevertheless, their studies in Brazil are rare. Thus, the objective of the present work was to evaluate the efficiency of the chelating agents EDDS and EDTA for the solubilization of heavy metals from two Oxisols contaminated by organic sources in Jaguariúna (LVJ and inorganic sources in Paulínia (LVP, São Paulo State, Southeastern Brazil. First, the soil samples were fractionated and the DTPA method was used to quantify heavy metals available forms. The results indicated that the metals were highly available in the soil fractions and could be solubilized by the chelating agents. The soil was suspended for 24 h in a chelating agent solution (EDTA or EDDS at rates of 0, 250, 500 and 750 mg kg-1 of soil. The concentration of solubilized heavy metals was determined in the resulting solution. The extent of metal solubilization varied according to soil type, the chelating agent added and the specific metal. The amount of iron solubilized, as compared to the total iron (LVJ was 11% (EDTA and 19% (EDDS. EDDS solubilized more Cu than EDTA in both soils but more Ni in LVJ, while EDTA solubilized more Zn in both soils but more Cd in LVP. Both EDTA and EDDS may be useful for phytoextraction from soils, although the iron content is an important factor regarding the phytoextraction of heavy metals with chelating agents in Oxisols.A fitoextração tem sido uma opção atrativa para remediar solos contaminados com metais pesados, principalmente quando associada à aplicação de quelantes ao solo, embora no Brasil seus estudos sejam muito incipientes. Portanto, o objetivo deste trabalho foi avaliar a eficiência dos quelantes EDTA e EDDS na solubilização de metais pesados em Latossolos contaminados por Cu, Zn, Cd e Ni, cujas fontes de contaminação foram: orgânica em Jaguariúna (LVJ e

  18. Preparation, Spectroscopic Investigation and Biological Activity of New Mixed Ligand Chelates

    International Nuclear Information System (INIS)

    Preparation and investigation of new Co(II), Ni(II), Zn(II) and Cr(III) chelates with mixed ligands including Schiff base (L1) formed from the condensation of 4-dimethylaminobenzaldehyde with 2-aminophenol and anthranilic acid (L2) were studied. The obtained Schiff base and mixed ligand chelates were subjected to several physiochemical techniques, in terms of CHN elemental analyses, molar conductivity, magnetic moment measurements, infrared, proton nuclear magnetic resonance, electronic and mass spectra. The analytical data showed the formation of the Schiff base compound and the ratio of metal to ligands of the chelates are 1:1:1(M:L1:L2). The infrared spectral data exhibited that the used ligands behaving as bidentate ligands towards the metal ions. The proton nuclear magnetic resonance spectral data showed the signals of the active groups in the ligands which entered in chelation with Zn(II) metal ion. The electronic spectral results showed the existence of pie (phenyl ring) and n = pie (C=N) of the ligands and suggested the geometrical structures of the chelates. Meanwhile, the mass spectral data revealed the fragmentations of the Schiff base, anthranilic acid and their Ni(II) mixed ligand chelate has been preformed the only chelate conducted for justification. All the prepared mixed chelates were non-electrolyte in nature. The antibacterial activity of the Schiff base, anthranilic acid, metal salts and mixed ligand chelates were studied and found to be that mixed ligand chelates have the most biological activity in comparison to the free ligands and salts. (author)

  19. Chelating regularities in the series of chelating polymer sorbents and their complexes with vanadium, manganese, and chromium

    International Nuclear Information System (INIS)

    Physicochemical properties of new synthesized polymer chelation sorbents - substituted polystyrene-azo-salicylic acid are investigated. Correlations between pKCOOH of functional groups of sorbents with chelation pH50 and vanadium, manganese and chromium lgstab are established with the aim of studying interactions in the ion of element - sorbent system. Established correlations suggest physicochemical properties of the sorbents and sorption parameters of cations of metals with the aim of concentration and separation of V(5), Mn(2) and Cr(3) microamounts from natural and technical objects including environmental ones

  20. Albumin microspheres labeled with Ga-67 by chelation: concise communication

    International Nuclear Information System (INIS)

    Albumin microspheres have been synthesized with EDTA and DTPA chelating groups covalently bound to their surface. The microspheres may be labeled with Ga-67 at high yield (97 +- 2%) by transcomplexation from a 0.1 M Ga-67 acetate solution. With EDTA microspheres the resulting label dissociates only slightly after 24 hr in 50% plasma at 370C, whereas with DTPA microspheres the label shows no detectable dissociation over this period. By contrast, microspheres without chelating groups lose their label virtually completely under these conditions. Following intravenous administration of sized Ga-67 DTPA microspheres in mice, about (84 +- 16)% of the activity localizes in the lungs at 5 min, with (60 +- 7)% remaining after 2 h. Since labeling is by chelation, the microspheres may also be tagged with other metallic radionuclides

  1. Albumin microspheres labeled with Ga-67 by chelation: concise communication

    International Nuclear Information System (INIS)

    Albumin microspheres have been synthesized eith EDTA and DTPA chelating groups covalently bound to their surface. The microspheres may be labeled with Ga-67 at high yield (97 +/- 2%) by transcomplexation from a 0.1 M Ga-67 acetate solution. With EDTA microspheres the resulting label dissociates only slightly after no detectable dissociation over this period. By contrast, microspheres without chelating groups lose their label virtually completely under these conditions. Following intravenous administration of sized Ga-67 DTPA microspheres in mice, about (84 +/- 16)% of the activity localizes in the lungs at 5 min, with (60 +/- 7)% remaining after 2 hr. Since labeling is by chelation, the microspheres may also be tagged with other metallic radionuclides

  2. Design, synthesis, and evaluation of polyhydroxamate chelators for selective complexation of actinides

    International Nuclear Information System (INIS)

    Specific chelating polymers targeted for actinides have much relevance to problems involving remediation of nuclear waste. Goal is to develop polymer supported, ion specific extraction systems for removing actinides and other hazardous metal ions from wastewaters. This is part of an effort to develop chelators for removing actinide ions such as Pu from soils and waste streams. Selected ligands are being attached to polymeric backbones to create novel chelating polymers. These polymers and other water soluble and insoluble polymers have been synthesized and are being evaluated for ability to selectively remove target metal ions from process waste streams

  3. Chelated minerals for poultry

    OpenAIRE

    SL Vieira

    2008-01-01

    Organic minerals have been subject of an increasing number of investigations recently. These compounds can be considered the most significant event regarding commercial forms of minerals targeting animal supplementation in the last decades. Minerals, especially metals, are usually supplemented in poultry feeds using cheap saline sources and have never required a lot of attention in terms of quality. On the other hand, definitions of organic minerals are very broad and frequently lead to confu...

  4. Europium(III)-chelates embedded in nanoparticles are protected from interfering compounds present in assay media

    International Nuclear Information System (INIS)

    Lanthanide chelates are excellent labels in ligand binding assays due to their long lifetime fluorescence, which enables efficient background reduction using time-resolved measurement. In separation-free homogeneous assays, however, some compounds in the sample may cause quenching of the lanthanide fluorescence and extra steps are required before these samples can be measured. In this study we have evaluated whether europium chelates packed inside a polystyrene nanoparticle are better protected from the environment than individual Eu(III)-chelates, and do these particles have higher tolerance against known interfering compounds (bivalent metal ions and variation of pH). We also tested whether metal ions had any effect on a fluorescence resonance energy transfer (FRET) based detection of a bioaffinity binding reaction. The presence of metal ions or variation of pH did not affect the fluorescence of the Eu(III)-chelate dyed nanoparticles, while significant decrease of the fluorescence was detected with a 9-dentate Eu(III)-chelate. Metal ions also decreased the fluorescence lifetime of the 9-dentate Eu(III)-chelate from 0.960 to 0.050 ms. Coloured metal ions caused a minor decrease in sensitised emission generated by FRET when Eu(III)-chelate dyed nanoparticles were used as donor labels. The decreased signal was due to the absorption of the sensitised emission by the coloured metal ions, since the metal ions had no effect on the lifetime of the sensitised emission. Thus the Eu(III)-chelate dyed nanoparticles are preferred labels in homogeneous bioaffinity assays, when interfering compounds are known to be present

  5. Overview of current chelation practices

    Directory of Open Access Journals (Sweden)

    Y. Aydinok

    2011-12-01

    Full Text Available Deferoxamine (DFO is reference standard therapy for transfusional iron overload since the 1980s. Although it is a highly effective iron chelator, the compliance problem to subcutaneous administration of DFO remains as the major problem. The oral chelator Deferiprone (DFP has no marketing licence in North America, however, it has been licensed in India since 1994 and the European Union (EU granted marketing approval for DFP in 1999, specifically for patients with thalassemia major when DFO is inadequate, intolerable or unacceptable. There are still limited data available on the use of DFP in children between 6 and 10 years of age, and no data on DFP use in children under 6 years of age. Subsequently the oral chelator Deferasirox (DFX was approved by FDA and EMA for the treatment of patients with transfusional iron overload -older than 2 years of age- as first line therapy, in 2005 and 2006 respectively. The primary objective of iron chelation is to maintain body iron at safe levels at all times but once iron is accumulated, the objective of iron chelation is to reduce tissue iron to safe levels which is a slow process. The chelation regimen, dose and frequency of administration, of the chelator(s are mainly determined based on body iron burden, presence of myocardial iron and the transfusional iron loading rate. A proper monitoring of chelation is of importance for measuring the response rate to a particular regimen and providing dose adjustments to enhance chelation efficacy and to avoid toxicity. Efficacy of a chelation regimen may exhibit individual variability resulting from factors such as absorbtion and metabolism of the chelator. Tolerability and compliance are also individual variables effecting the response to chelation. Understanding of advantages and limitations of chelators, accurately determining chelation needs of patients with iron overload and designing individualized chelation regimens with less toxicity but optimum efficacy

  6. Chelation: A Fundamental Mechanism of Action of AGE Inhibitors, AGE Breakers, and Other Inhibitors of Diabetes Complications

    OpenAIRE

    Nagai, Ryoji; Murray, David B.; Metz, Thomas O.; Baynes, John W.

    2012-01-01

    This article outlines evidence that advanced glycation end product (AGE) inhibitors and breakers act primarily as chelators, inhibiting metal-catalyzed oxidation reactions that catalyze AGE formation. We then present evidence that chelation is the most likely mechanism by which ACE inhibitors, angiotensin receptor blockers, and aldose reductase inhibitors inhibit AGE formation in diabetes. Finally, we note several recent studies demonstrating therapeutic benefits of chelators for diabetic car...

  7. Determination of trace metal ions via on-line separation and preconcentration by means of chelating Sepharose beads in a sequential injection lab-on-valve (SI-LOV) system coupled to electrothermal atomic absorption spectrometric detection

    DEFF Research Database (Denmark)

    Long, Xiangbao; Hansen, Elo Harald; Miró, Manuel

    2005-01-01

    The analytical performance of an on-line sequential injection lab-on-valve (SI-LOV) system using chelating Sepharose beads as sorbent material for the determination of ultra trace levels of Cd(II), Pb(II) and Ni(II) by electrothermal atomic absorption spectrometry (ETAAS) is described and discussed...

  8. Iron chelation and multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Kelsey J. Weigel

    2014-01-01

    Full Text Available Histochemical and MRI studies have demonstrated that MS (multiple sclerosis patients have abnormal deposition of iron in both gray and white matter structures. Data is emerging indicating that this iron could partake in pathogenesis by various mechanisms, e.g., promoting the production of reactive oxygen species and enhancing the production of proinflammatory cytokines. Iron chelation therapy could be a viable strategy to block iron-related pathological events or it can confer cellular protection by stabilizing hypoxia inducible factor 1α, a transcription factor that normally responds to hypoxic conditions. Iron chelation has been shown to protect against disease progression and/or limit iron accumulation in some neurological disorders or their experimental models. Data from studies that administered a chelator to animals with experimental autoimmune encephalomyelitis, a model of MS, support the rationale for examining this treatment approach in MS. Preliminary clinical studies have been performed in MS patients using deferoxamine. Although some side effects were observed, the large majority of patients were able to tolerate the arduous administration regimen, i.e., 6–8 h of subcutaneous infusion, and all side effects resolved upon discontinuation of treatment. Importantly, these preliminary studies did not identify a disqualifying event for this experimental approach. More recently developed chelators, deferasirox and deferiprone, are more desirable for possible use in MS given their oral administration, and importantly, deferiprone can cross the blood–brain barrier. However, experiences from other conditions indicate that the potential for adverse events during chelation therapy necessitates close patient monitoring and a carefully considered administration regimen.

  9. Production and chelation properties of Lu-177, the isotope suitable for nuclear medicine applications

    International Nuclear Information System (INIS)

    Lutetium-177 is one of the most favoured radionuclides for radiotherapeutic applications due to its suitable nuclear characteristics. It has been mainly used in three areas: labelling of biomolecules (i.e., somatostatine analogues and monoclonal antibodies), palliative therapy of bone skeletal metastases, and radiation synovectomy. At present, Lu- labelled chelates with aminocarboxylates, like a DOTA or DTPA have been deeply investigated from the point of view of chelation properties. This research has been targeted on finding the optimal conditions of chelation to obtain high yields of chelates and on monitoring their kinetic stability, depending on particular factors (i.e., pH, molar ratios metal: ligand or duration of the reaction). The Lu-DTPA and Lu-DOTA chelates were prepared and detected radiochromatographically by TLC. For this purpose ITLC SG plates were used as a solid phase, and a mixture of hydroxylamine:methanol:water (0.2:2:4) was used as a liquid phase. (author)

  10. Copper and Zinc Chelation as a Treatment of Alzheimer's Disease

    Science.gov (United States)

    Hodak, Miroslav; Bernholc, Jerry

    2014-03-01

    Alzheimer's disease (AD) is a neurodegenerative disorder affecting millions of people in the U.S. The cause of the disease remains unknown, but amyloid- β (A β), a short peptide, is considered causal its pathogenesis. At cellular level, AD is characterized by deposits mainly composed of A β that also contain elevated levels of transition metals ions. Targeting metals is a promising new strategy for AD treatment, which uses moderately strong metal chelators to sequester them from A β or the environment. PBT2 is a chelating compound that has been the most promising in clinical trials. In our work, we use computer simulations to investigate complexes of a close analog of PBT2 with Cu2+ and Zn2+ ions. The calculations employ KS/FD DFT method, which combines Kohn-Sham DFT with the frozen-density DFT to achieve efficient description of explicit solvent beyond the first solvation shell. Our work is based on recent experiments and examines both 1:1 and 2:1 chelator-metal stochiometries detected experimentally. The results show that copper attaches more strongly than zinc, find that 1:1 complexes involve water in the first coordination shell and determine which one of several possible 2:1 geometries is the most preferable.

  11. Assessing the Impact of EDTA Chelating Effect on some Macro- and Microminerals in Prussian Carp (Carassius Gibelio) Tissues

    OpenAIRE

    Marioara Nicula; Iosif Gergen; Monica Harmanescu; Ionut Banatean-Dunea; Adela Marcu; Eliza Simiz; Tiberiu Polen; Mihai Lunca

    2011-01-01

    Chelators are used in chemical analysis, in medical aplications, as water softeners, as decontamination agents on radioactive surfaces and they are ingredients in many commercial products such as shampoos and food preservatives. Such a synthetic chelator is EDTA (ethylenediaminetetraacetic acid). It is considered one of the tools that promises to control the heavy metal pollution in aquaculture. EDTA attaches itself to heavy metals and carries the metals from the fish body. EDTA can also slow...

  12. MULTIDENTATE TEREPHTHALAMIDATE AND HYDROXYPYRIDONATE LIGANDS: TOWARDS NEW ORALLY ACTIVE CHELATORS

    Energy Technology Data Exchange (ETDEWEB)

    Abergel, Rebecca J.; Raymond, Kenneth N.

    2011-07-13

    The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using {sup 59}Fe, {sup 238}Pu, and {sup 241}Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents [deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides] and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity.

  13. Multidentate Terephthalamidate And Hydroxypyridonate Ligands: Towards New Orally Active Chelators

    International Nuclear Information System (INIS)

    The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using 59Fe, 238Pu, and 241Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents (deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides) and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity.

  14. Iron chelation and multiple sclerosis

    OpenAIRE

    Kelsey J. Weigel; Sharon G. Lynch; Steven M. LeVine

    2014-01-01

    Histochemical and MRI studies have demonstrated that MS (multiple sclerosis) patients have abnormal deposition of iron in both gray and white matter structures. Data is emerging indicating that this iron could partake in pathogenesis by various mechanisms, e.g., promoting the production of reactive oxygen species and enhancing the production of proinflammatory cytokines. Iron chelation therapy could be a viable strategy to block iron-related pathological events or it can confer cellular prote...

  15. Some Linguistic Detail on Chelation

    Science.gov (United States)

    Haworth, Daniel T.

    1998-01-01

    The term chelate was first applied by Morgan and Drew in 1920 to describe the heterocyclic rings formed from bidentate ligands bonding to a central atom. The history of the word ch_l_ is traced from its original Greek meaning through the Latin language to its anglicized form, chela. This word has a very rich history and has been cited by both Greek (Aristotle) and Latin (Cicero, Vergil) philosophers and poets.

  16. Diagnostic chelation challenge with DMSA: a biomarker of long-term mercury exposure?

    OpenAIRE

    Frumkin, H; Manning, C C; Williams, P. L.; Sanders, A; Taylor, B.B.; Pierce, M; Elon, L; Hertzberg, V S

    2001-01-01

    Chelation challenge testing has been used to assess the body burden of various metals. The best-known example is EDTA challenge in lead-exposed individuals. This study assessed diagnostic chelation challenge with dimercaptosuccinic acid (DMSA) as a measure of mercury body burden among mercury-exposed workers. Former employees at a chloralkali plant, for whom detailed exposure histories were available (n = 119), and unexposed controls (n = 101) completed 24-hr urine collections before and afte...

  17. The Role of Chelation in the Treatment of Arsenic and Mercury Poisoning

    OpenAIRE

    Kosnett, Michael J

    2013-01-01

    Chelation for heavy metal intoxication began more than 70 years ago with the development of British anti-lewisite (BAL; dimercaprol) in wartime Britain as a potential antidote the arsenical warfare agent lewisite (dichloro[2-chlorovinyl]arsine). DMPS (unithiol) and DMSA (succimer), dithiol water-soluble analogs of BAL, were developed in the Soviet Union and China in the late 1950s. These three agents have remained the mainstay of chelation treatment of arsenic and mercury intoxication for mor...

  18. Synthesis and Characterization of polyacrylamide Chelating Resin with Thenoyltrifluoroacetone for Separation of Thorium from Uranium

    International Nuclear Information System (INIS)

    New effective chelating resin is synthesized by immobilization of Thenoyltrifluoroacetone (HTTA) on cross linked polyacrylamide. The chelating exchanger is used for separation of uranium (UO22+) and thorium(Th4+). The analyzed metal ions were quantitatively measured by ion chromatographic technique coupled with UV/V is detector and derivatization reaction of Arsenazo(III) at wavelength 660 nm. Different factors affecting the metal ions uptake and hence the separation efficient c y of the chelating polyacrylamide resin were investigated. Optimization of conditions showed that maximum uptake of UO22+ and Th4+ are at ph 4.0 and 3.0 respectively. Isothermal capacity shows a relatively high capacity of the chelating resin towards divalent uranium more than that of tetravalent thorium. The capacity of the chelating resin for UO22+ and Th4+ was found to be 0.05 and 0.034 mmol/gm, respectively. Separation of UO22+ and Th4+ was successively performed using column chromatographic technique loaded with the chelating resin. The retained metal ions were sequentially separated by i socratic elution using 0.1 M HNO3

  19. Status of chelation research: a review

    International Nuclear Information System (INIS)

    The current status of research on the removal of actinide elements from the body is reviewed. Items occurring prior to 1980 include evidence for fetal toxicity from Ca-DTPA, the FDA approval of Zn-DTPA for human therapy, the mixed ligand fiasco, and the abrupt wipeout of chelation funding. New concepts that should be explored include improvements in removing radioactivity from lung and bone, the effectiveness of DTPA inside cells, simultaneous therapy with mobilizing agents and chelating agents, prolonging the retention of chelating agents within the body, the oral administration of chelating agents, the effectiveness of LICAM and other new chelating agents, the safety of decorporation procedures, and the effectiveness of chelation therapy on reducing the risk from radionuclide-induced cancer. Some physicians give DTPA by intravenous injection, a safe procedure that should be officially sanctioned

  20. Iron Chelation Therapy in Myelodysplastic Syndromes

    OpenAIRE

    Giuseppe Saglio; Daniela Cilloni; Emanuela Messa

    2010-01-01

    Myelodysplastic syndromes (MDS) are a heterogeneous disorder of the hematopoietic stem cells, frequently characterized by anemia and transfusion dependency. In low-risk patients, transfusion dependency can be long lasting, leading to iron overload. Iron chelation therapy may be a therapeutic option for these patients, especially since the approval of oral iron chelators, which are easier to use and better accepted by the patients. The usefulness of iron chelation in MDS patients is still unde...

  1. Beliefs about chelation among thalassemia patients

    OpenAIRE

    Trachtenberg Felicia L; Mednick Lauren; Kwiatkowski Janet L; Neufeld Ellis J; Haines Dru; Pakbaz Zahra; Thompson Alexis A; Quinn Charles T; Grady Robert; Sobota Amy; Olivieri Nancy; Horne Robert; Yamashita Robert

    2012-01-01

    Abstract Background Understanding patients’ views about medication is crucial to maximize adherence. Thalassemia is a congenital blood disorder requiring chronic blood transfusions and daily iron chelation therapy. Methods The Beliefs in Medicine Questionnaire (BMQ) was used to assess beliefs in chelation in thalassemia patients from North America and London in the Thalassemia Longitudinal Cohort (TLC) of the Thalassemia Clinical Research Network (TCRN). Chelation adherence was based on patie...

  2. Environmental biogeochemistry of chelating agents and recommendations for the disposal of chelated radioactive wastes

    International Nuclear Information System (INIS)

    The environmental chemistry of the three most common aminopolycarboxylic acid chelating agents, NTA (nitrilotriacetic acid), EDTA (ethylenediaminetetraacetic acid), and DTPA (diethylenetriaminepentaacetic acid) is reviewed. This review includes information on their persistence in the environment, as well as their tendency to form complexes with actinides. Data on the sorption of chelated actinides by geologic substrates and on the uptake of chelated actinides by plants are also presented. Three different technical options for disposing chelated low-level radioactive wastes are proposed: bind the solidified chelated waste in some kind of solid matrix that has a slow leach rate and bury the waste in a ''dry'' disposal site; substitute biodegradable chelating agents in the decontamination reagent for the chelating agents that are persistent in the environment; chemically or thermally degrade the chelating agents in the waste prior to disposal. The relative advantages and disadvantages of each of these options are discussed. 81 refs

  3. Effectiveness of chelation therapy with time after acute uranium intoxication

    International Nuclear Information System (INIS)

    The effect of increasing the time interval between acute uranium exposure and chelation therapy was studied in male Swiss mice. Gallic acid, 4,5-dihydroxy-1,3- benzenedisulfonic acid (Tiron), diethylenetriaminepentaacetic acid (DTPA), and 5-aminosalicylic acid (5-AS) were administered ip at 0, 0.25, 1, 4, and 24 hr after sc injection of 10 mg/kg of uranyl acetate dihydrate. Chelating agents were given at doses equal to one-fourth of their respective LD50 values. Daily elimination of uranium into urine and feces was determined for 4 days after which time the mice were killed, and the concentration of uranium was measured in kidney, spleen, and bone. The excretion of uranium was especially rapid in the first 24 hr. Treatment with Tiron or gallic acid at 0, 0.25, or 1 hr after uranium exposure significantly increased the total excretion of the metal. In kidney and bone, only administration of Tiron at 0, 0.25, or 1 hr after uranium injection, or gallic acid at 1 hr after uranium exposure significantly reduced tissue uranium concentrations. Treatment at later times (4 to 24 hr) did not increase the total excretion of the metal and did not decrease the tissue uranium concentrations 4 days after uranyl acetate administration. The results show that the length of time before initiating chelation therapy for acute uranium intoxication greatly influences the effectiveness of this therapy

  4. Generation, Fractionation, and Characterization of Iron-Chelating Protein Hydrolysate from Palm Kernel Cake Proteins.

    Science.gov (United States)

    Zarei, Mohammad; Ghanbari, Rahele; Tajabadi, Naser; Abdul-Hamid, Azizah; Bakar, Fatimah Abu; Saari, Nazamid

    2016-02-01

    Palm kernel cake protein was hydrolyzed with different proteases namely papain, bromelain, subtilisin, flavourzyme, trypsin, chymotrypsin, and pepsin to generate different protein hydrolysates. Peptide content and iron-chelating activity of each hydrolysate were evaluated using O-phthaldialdehyde-based spectrophotometric method and ferrozine-based colorimetric assay, respectively. The results revealed a positive correlation between peptide contents and iron-chelating activities of the protein hydrolysates. Protein hydrolysate generated by papain exhibited the highest peptide content of 10.5 mM and highest iron-chelating activity of 64.8% compared with the other hydrolysates. Profiling of the papain-generated hydrolysate by reverse phase high performance liquid chromatography fractionation indicated a direct association between peptide content and iron-chelating activity in most of the fractions. Further fractionation using isoelectric focusing also revealed that protein hydrolysate with basic and neutral isoelectric point (pI) had the highest iron-chelating activity, although a few fractions in the acidic range also exhibited good metal chelating potential. After identification and synthesis of papain-generated peptides, GGIF and YLLLK showed among the highest iron-chelating activities of 56% and 53%, whereas their IC50 were 1.4 and 0.2 μM, respectively. PMID:26720491

  5. Enhancing Potentially Plant-Available Lead Concentrations in Contaminated Residential Soils Using a Biodegradable Chelating Agent

    Science.gov (United States)

    Andra, S.; Datta, R.; Sarkar, D.; Saminathan, S.

    2007-12-01

    Chelation of heavy metals is an important factor in enhancing metal solubility and, hence, metal availability to plants to promote phytoremediation. In the present study, we compared the effects of application of a biodegradable chelating agent, namely, ethylenediaminedisuccinic acid (EDDS) on enhancing plant available form of lead (Pb) in Pb-based paint contaminated residential soils compared to that of a more commonly used, but non-biodegradable chelate, i.e., ethylenediaminetetraacetic acid (EDTA). Development of a successful phytoremediation model for metals such as Pb depends on a thorough understanding of the physical and chemical properties of the soil, along with the optimization of a chelate treatment to mobilize Pb from `unavailable' pools to potentially plant available fraction. In this context, we set out to perform batch incubation experiments to investigate the effectiveness of the two aforementioned chelates in enhancing plant available Pb at four different concentrations (0, 5, 10 and 15 mM/kg soil) and three treatment durations (0, 10 and 30 days). We selected 12 contaminated residential soils from two major metropolitan areas (San Antonio, TX and Baltimore, MD) with varying soil physico-chemical properties - the soils from San Antonio were primarily alkaline and those from Baltimore were typically acidic. Total soil Pb concentrations ranged between 256 mg/kg and 4,182 mg/kg. Our results show that both chelates increased the solubility of Pb, otherwise occluded in the complex soil matrix. For both EDTA and EDDS, the exchangeable concentrations of soil Pb also increased with increase in chelate concentration and incubation time. The most effective treatment was 15 mM chelate kg-1 soil incubated for 30 days, which caused many fold increase in potentially plant available Pb (a combination of the soluble and exchangeable fractions) relative to the unamended controls. Step wise multiple linear regression analysis using chelate-extractable Pb and soil

  6. Serum stability of 67Cu chelates: comparison with 111In and 57Co

    International Nuclear Information System (INIS)

    Simple chelates and chelate conjugated monoclonal antibodies labeled with 111In, 57Co and 67Cu demonstrate marked differences in stability when exposed to a serum environment. Among these radiometals, on DTPA, the order of stability is 111In > 57Co >> 67Cu. On benzyl-EDTA, the order of stability is 111In approx. 57Co >> 67Cu. Among those investigated, the only serum stable 67Cu chelate found was 67>Cu-TETA. The order of stability observed for 57Co vs 67Cu is contrary to published equilibrium constants. These in vitro studies suggest that the in vivo behavior of metal chelates exposed to a complex molecular environment may not be predicted by classically determined equilibrium constants. (author)

  7. Effect of chelating agents on the distribution of monoclonal antibodies in mice

    International Nuclear Information System (INIS)

    The potential for altering the biodistribution of radiolabel from gallium- and indium-labeled mouse monoclonal antibodies was investigated in mice using metal chelating agents. The chelating agents used were desferrioxamine (DFO), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine-di (O-hydroxyphenylacetic acid) (EDHPA), and 2,2' dipyridyl (DIPY). The mouse monoclonal antibody LICR-LON-M8 was labeled with 111In after conjugation to DTPA, and with 67Ga after conjugation to DFO. All the chelating agents except DIPY altered the biodistribution of [67Ga]citrate and [111In]citrate but did not affect the 48-hr tissue uptake of label from [111In]DTPA-M8 or [67Ga]DFO-M8, confirming the in vivo stability of the antibody conjugates. Label fixed in the tissues was inaccessible to the chelating agents, indicating that they will not be suitable for reducing the high background liver radioactivity in patients undergoing scanning with indium-labeled antibodies

  8. Importance of iron chelation therapy

    OpenAIRE

    A. Varoğlu

    2011-01-01

    It is necessary to remember that today patients have different options of chelation treatment, as desferrioxamine, deferiprone and deferasirox are available. However, a patient has to be compliant with treatments. They have always to remember that too much iron causes different complications and could be a barrier for a definitive cure from thalassemia. 由于出现了去铁胺、去铁酮和去铁斯若等药物,病人现在可以选择不同的螯合治疗方式。 然而,病人必须适应这几种治疗方式。 他们必须时刻记住太多的铁元素会引发多种并发症,并对地中海贫血的彻底治疗造成阻碍。...

  9. Spectral, magnetic and antifungal activities of some novel lanthanon chelates of Schiff bases containing oxygen and nitrogen donor atoms

    International Nuclear Information System (INIS)

    Lanthanon chelates of the type (LnL2) and (LnL3) where Ln = La(III), Pr(III), Nd(III), Sm(III), Ho(III) and Er(III) and L = acetylacetonethiosemicarbazide (AAS) and L' = benzoylacetonethiosemicarbazide (BAS) have been isolated in solid state and are characterized by their spectral, magnetic and antifungal activities. The electronic spectra of these chelates have been analyzed in the light of LSJ terms and involving characteristic f - f transitions. The ligands and their resulting chelates have been shown to be toxic against the two pathogenic fungi, viz., Aspargillus niger and Draschelara australiensis and the results revealed that the toxicity decreases on chelation or metallation. Overall, the benzoylacetonesemicarbazide lanthanon chelates are more toxic to fungi than the corresponding lanthanon derivatives of acetylacetonesemicarbazide. (author)

  10. EXTRACTION, RECOVERY, AND BIOSTABILITY OF EDTA FOR REMEDIATION OF HEAVY METAL-CONTAMINATED SOIL. (R825549C052)

    Science.gov (United States)

    Chelation removal of heavy metals from contaminated soil is seen as a viable remediation technique. A useful chelating agent should be strong, reusable, and biostable during metal extraction and recovery operations. This work tested the extraction, recovery, and biostability o...

  11. Development of Iron-Chelating Poly(ethylene terephthalate) Packaging for Inhibiting Lipid Oxidation in Oil-in-Water Emulsions.

    Science.gov (United States)

    Johnson, David R; Tian, Fang; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2015-05-27

    Foods such as bulk oils, salad dressings, and nutritionally fortified beverages that are susceptible to oxidative degradation are often packaged in poly(ethylene terephthalate) (PET) bottles with metal chelators added to the food to maintain product quality. In the present work, a metal-chelating active packaging material is designed and characterized, in which poly(hydroxamic acid) (PHA) metal-chelating moieties were grafted from the surface of PET. Biomimetic PHA groups were grafted in a two-step UV-initiated process without the use of a photoinitiator. Surface characterization of the films by attenuated total reflective Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM) suggested successful grafting and conversion of poly(hydroxyethyl acrylate) (PHEA) to PHA chelating moieties from the surface of PET. Colorimetric (ferrozine) and inductively coupled plasma mass spectroscopy (ICP-MS) assays demonstrated the ability of PET-g-PHA to chelate iron in a low-pH (3.0) environment containing a competitive metal chelator (citric acid). Lipid oxidation studies demonstrated the antioxidant activity of PET-g-PHA films in inhibiting iron-promoted oxidation in an acidified oil-in-water (O/W) emulsion model system (pH 3.0). Particle size and ζ-potential analysis indicated that the addition of PET-g-PHA films did not affect the physical stability of the emulsion system. This work suggests that biomimetic chelating moieties can be grafted from PET and effectively inhibit iron-promoted degradation reactions, enabling removal of metal-chelating additives from product formulations. PMID:25985711

  12. New epoxide polymers generated by metal organic catalysts (chelates) and their application in composite structures. Pt. 2. Final report; Neue Epoxidpolymere durch Metallorgano-Katalysatoren und ihr Einsatz in Faserverbundstrukturen. T. 2. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Merz, T.; Raeckers, B.

    1999-08-01

    Epoxy resins cured by catalysts based on chelate compound can offer an additional potential concerning storage and heat stability, toughness and curing characteristic. To prove these advantages and to prepare a serial application was target of the project, by which physico-chemical investigations, determination of mechanical properties and component tests were used. Besides an improvement of storage time and a minimized curing cycle a satisfactory processing behaviour and mechanical properties approaching currently used aircraft materials became evident. Serial production of fibre reinforced components for automotive industry is basically possible, because all requirements concerning costs, performance and station time were met. The results can also be used for new applications in other technical fields like apparatus construction or sporting goods industry. (orig.) [German] Mittels Metallorganokatalysatoren gehaertete Epoxidharze versprechen gegenueber herkoemmlichen Systemen zusaetzliche Potentiale hinsichtlich Lager- und Waermestabilitaet sowie Zaehigkeit und Haertungscharakteristik. Diese nachzuweisen und eine zukuenftige Serienanwendung vorzubereiten war Ziel des Projektes, wozu physico-chemische Untersuchungen, mechanische Kennwertermittlungen und Bauteilversuche dienten. Neben verbesserter Lagerstabilitaet und minimierten Haertungszyklen konnten gute Verarbeitungseingeschaften und ein Leistungsprofil nachgewiesen werden, das nahe an das heutiger Luftfahrtwerkstoffe heranreicht. Die Serienherstellung von Faserverbundbauteilen im Automobilbau ist prinzipiell moeglich, da durch die entwickelten Katalysatoren alle Vorgaben hinsichtlich Kosten, Leistungsfaehigkeit und Taktzeiten erreicht werden konnten. Hierdurch koennen sich auch fuer andere Bereiche (z.B. Geraetebau, Sportartikelindustrie) neue Anwendungsmoeglichkeiten eroeffnen. (orig.)

  13. New epoxide polymers generated by metal organic catalysts (chelates) and their application in composite structures. Pt. 1. Final report; Neue Epoxidpolymere durch Metallorgano-Katalysatoren und ihr Einsatz in Faserverbundstrukturen. T. 1. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Merz, T.; Raeckers, B.; Boettcher, A.; Haessler, R.; Renner, M.; Schmidtke, K.

    1999-08-01

    Epoxy resins cured by catalysts based on chelate compound can offer an additional potential concerning storage and heat stability, toughness and curing characteristic. To prove these advantages and to prepare a serial application was target of the project, by which physico-chemical investigations, determination of mechanical properties and component tests were used. Besides an improvement of storage time and a minimized curing cycle a satisfactory processing behaviour and mechanical properties approaching currently used aircraft materials became evident. Serial production of fibre reinforced components for automotive industry is basically possible, because all requirements concerning costs, performance and station time were met. The results can also be used for new applications in other technical fields like apparatus construction or sporting goods industry. (orig.) [German] Mittels Metallorganokatalysatoren gehaertete Epoxidharze versprechen gegenueber herkoemmlichen Systemen zusaetzliche Potentiale hinsichtlich Lager- und Waermestabilitaet sowie Zaehigkeit und Haertungscharakteristik. Diese nachzuweisen und eine zukuenftige Serienanwendung vorzubereiten war Ziel des Projektes, wozu physico-chemische Untersuchungen, mechanische Kennwertermittlungen und Bauteilversuche dienten. Neben verbesserter Lagerstabilitaet und minimierten Haertungszyklen konnten gute Verarbeitungseingeschaften und ein Leistungsprofil nachgewiesen werden, das nahe an das heutiger Luftfahrtwerkstoffe heranreicht. Die Serienherstellung von Faserverbundbauteilen im Automobilbau ist prinzipiell moeglich, da durch die entwickelten Katalysatoren alle Vorgaben hinsichtlich Kosten, Leistungsfaehigkeit und Taktzeiten erreicht werden konnten. Hierdurch koennen sich auch fuer andere Bereiche (z.B. Geraetebau, Sportartikelindustrie) neue Anwendungsmoeglichkeiten eroeffnen. (orig.)

  14. Synthesis of LaNiO3 perovskite type by chelating precursor method using EDTA: optimization of chelating content

    International Nuclear Information System (INIS)

    The perovskites are strategic materials due their catalytic, electronic and magnetic properties. These properties are influenced by the calcination and synthesis conditions. In this work was carried out the synthesis of LaNiO3 perovskite type by chelating precursor method using EDTA and also was studied the optimization of the EDTA content in the synthesis. The synthesized materials were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TG) and Infrared Spectroscopy (FTIR). In the optimization of the EDTA content the lowest ratio of metal / EDTA used was 1.0 / 0.1, where it was possible to obtain monophasic perovskite. (author)

  15. Chelation therapy after the Trial to Assess Chelation Therapy: results of a unique trial

    OpenAIRE

    Maria D. Avila; Escolar, Esteban; Lamas, Gervasio A.

    2014-01-01

    Purpose of review EDTA chelation therapy has been in off-label use for the treatment of atherosclerosis. We review the results of the first large-scale randomized trial of this treatment. Recent findings The trial to assess chelation therapy was a $30 million National Institutes of Health-funded study of the safety and efficacy of EDTA-based chelation infusions in 1708 post-myocardial infarction (MI) patients. The trial to assess chelation therapy demonstrated a significant (P = 0.035) 18% re...

  16. Chelating Tendencies of Bioactive Aminophosphonates

    OpenAIRE

    Kiss, Tamas; Lázár, István; Kafarski, Pawel

    1994-01-01

    The metal-binding abilities of a wide variety of bioactive aminophosphonates, from the simple aminoethanephosphonic acids to the rather large macrocyclic polyaza derivatives, are discussed with special emphasis on a comparison of the analogous carboxylic acid and phosphonic acid systems. Examples are given of the biological importance of metal ion – aminophosphonate interactions in living systems, and also of their actual and potential applicability in medicine.

  17. Improvement of Oxidative and Metabolic Parameters by Cellfood Administration in Patients Affected by Neurodegenerative Diseases on Chelation Treatment

    OpenAIRE

    Alessandro Fulgenzi; Rachele De Giuseppe; Fabrizia Bamonti; Maria Elena Ferrero

    2014-01-01

    Objective. This prospective pilot study aimed at evaluating the effects of therapy with antioxidant compounds (Cellfood, and other antioxidants) on patients affected by neurodegenerative diseases (ND), who displayed toxic metal burden and were subjected to chelation treatment with the chelating agent calcium disodium ethylenediaminetetraacetic acid (CaNa2EDTA or EDTA). Methods. Two groups of subjects were studied: (a) 39 patients affected by ND and (b) 11 subjects unaffected by ND (controls)....

  18. Current Use of Chelation in American Health Care

    OpenAIRE

    Wax, Paul M.

    2013-01-01

    The National Center for Health Statistics estimates that more than 100,000 Americans receive chelation each year, although far fewer than 1 % of these cases are managed by medical toxicologists. Unfortunately, fatalities have been reported after inappropriate chelation use. There are currently 11 FDA-approved chelators available by prescription although chelation products may also be obtained through compounding pharmacies and directly over the internet. Promotion of chelation training is pro...

  19. Analysis of hydrosoluble organic chelating agents. Potentialities of capillary electrophoresis and ionic chromatography

    International Nuclear Information System (INIS)

    Capillary electrophoresis and ion exchange chromatography are good techniques for the determination of organic chelating agents as mono or poly-carboxylates. Ion exchange chromatography allows to obtain very high sensitivities (a few μg/L). Capillary electrophoresis generates practically none analytical waste; this technique is then very interesting for nuclear industry. This microanalysis technique has been here carried out for the determination of organic chelating agents in leaching water of an old waste for which an important release rate of radio-toxic metals had been found. Thus, formate and especially acetate ions have been correlated with this unusual behaviour

  20. DCCP and DICP: Construction and Analyses of Databases for Copper- and Iron-Chelating Proteins

    Institute of Scientific and Technical Information of China (English)

    Hao Wu; Yan Yang; Sheng-Juan Jiang; Ling-Ling Chen; Hai-Xia Gao; Qing-Shan Fu; Feng Li; Bin-Guang Ma; Hong-Yu Zhang

    2005-01-01

    Copper and iron play important roles in a variety of biological processes, especially when being chelated with proteins. The proteins involved in the metal binding,transporting and metabolism have aroused much interest. To facilitate the study on this topic, we constructed two databases (DCCP and DICP) containing the known copper- and iron-chelating proteins, which are freely available from the website http:∥sdbi.sdut.edu.cn/en. Users can conveniently search and browse all of the entries in the databases. Based on the two databases, bioinformatic analyses were performed, which provided some novel insights into metalloproteins.

  1. Complexes of quinone-functionalized chelating ligands for multiple electron/proton transfer reduction reactions

    Energy Technology Data Exchange (ETDEWEB)

    Durfee, W.S.; Pierpont, C.G. (Univ. of Colorado, Boulder (United States))

    1993-03-03

    Quinone-functionalized chelating ligands may be used to effect sequential electron/proton transfer steps necessary for the reduction of substrate molecules coordinated to a complexed metal ion. The chelating ligand (NQ)[sub 2]en has been synthesized by condensing 2 equiv of 2-hydroxy-3-acetyl-1,4-naphthoquinone with ethylenediamine. Complexes of Cu(II) and Ni(II) have been prepared and characterized. Electrochemical properties of the complexes show that, in the fully reduced bis(hydroquinone) form, the ligand would be able to provide four electrons and protons to a coordinated substrate molecule at strongly negative potentials. 8 refs., 2 figs.

  2. Removal of cobalt- and mercury-EDTA chelates from aqueous solutions with a macroporous char

    International Nuclear Information System (INIS)

    A bench-scale method was developed to remove cobalt- and mercury-EDTA chelates from water onto macroporous char. Experimental parameters included variations on solution pH, char pre-treatment, cobalt oxidation state, and apparatus configuration. The use of 60Co and 203Hg radiotracers allowed for total accountability of the metals in the char and effluents. Overall experimental results demonstrate the applicability of treated macroporous chars for the effective removal of both cobalt and mercury EDTA chelates from aqueous solutions. The char system was optimized to sequester 97.5% and 99.8% of the cobalt- and mercury-EDTA from 20 ppm solutions, respectively. (author)

  3. Chelation behavior of various flavonols and transfer of flavonol-chelated zinc(II) to alanylaspartic dipeptide: A PCM/DFT investigation

    Science.gov (United States)

    Yasarawan, Nuttawisit; Thipyapong, Khajadpai; Ruangpornvisuti, Vithaya

    2016-03-01

    Alanylaspartic dipeptide (AlaAsp) and zinc(II)-flavonol complex could represent a metal-binding site in proteins and a metal-ion releasing agent, respectively. Chelation of zinc(II) by either AlaAsp or flavonol ligands in aqueous solution has been examined using DFT methods with polarizable continuum model (PCM/DFT). Coordination geometry, complexation stoichiometry, coordination bond strength, preferable metal-binding site on ligands and effect of water coordination on the stability of complexes have been addressed. In several cases, the long-range corrected density functional CAM-B3LYP allows the most accurate prediction of both structural and spectroscopic data. The preferential transfer of flavonol-chelated zinc(II) to AlaAsp under solvation is attainable through the ligand-exchange reaction. The energy barrier of such reaction is significantly dependent on the degree of hydrogen bonding within the transition state. In summary, either hydroxylation or methoxylation at particular positions on the 3-hydroxyflavone backbone significantly affects the reactivity of flavonol chelates in the metal-ion transfer.

  4. Production of chelating agents by Pseudomonas aeruginosa grown in the presence of thorium and uranium

    International Nuclear Information System (INIS)

    Chelating agents produced by microorganisms enhance the dissolution of iron increasing the mobility and bioavailability of the metal. Since some similarities exist in the biological behavior of ferric, thorium and uranyl ions, microorganisms resistant to these metals and which grow in their presence may produce sequestering agents of Th and U, and other metals in a manner similar to the complexation of iron by siderophores. The ability of P. aeruginosa to elaborate sequestering agents in medium containing thorium or uranium salts was tested. Uranium has a stronger inhibitory effect on growth of the organism than thorium at similar concentrations. Analyses of the culture media have shown, that relative to the control, and under the experimental conditions used, the microorganisms have produced several new chelating agents for thorium and uranium. Extracts containing these chelating agents have been tested for their decorporation potential. In vitro mouse liver bioassay and in vivo mouse toxicity tests indicate that their efficiency is comparable to DTPA and DFOA and that they are virtually non-toxic to mice. The bacterially produced compounds resemble, but are not identical to the known iron chelating siderophores isolated from microorganisms. Some of their chemical properties are also discussed. (author)

  5. Mixed Intramolecular Hydrogen Bonding in Dihydroxythiophene-based Units and Boron and Technetium Chelation

    International Nuclear Information System (INIS)

    Three novel potential metal ion chelating units have been synthesized and characterized: 5-hexylcarbamoyl- 3,4-dihydroxythiophene-2-carboxylic acid methyl ester (5), 3-benzyloxy-4-hydroxythiophene-2,5-dicarboxylic acid bis-hexylamide (6), and 3,4-dihydroxythiophene-2,5-dicarboxylic acid bis-hexylamide (7). The crystal structure of 6 was obtained and suggests the presence of three distinct intramolecular hydrogen bonds, namely [Namide-H···O] [O-H···Oamide] and [Namide-H···S]. Boron chelation with 5, 6 and 7 through the use of BF3, B(OH)3 or B(OMe)3 was probed by 1H, 11B, and 13C NMR spectroscopy. Technetium (I) chelation with 5, 6 and 7 was also studied via HPLC elutions using [99mTc(CO)3(OH2)3]+

  6. Optimisation and status of chelation therapy

    International Nuclear Information System (INIS)

    The calcium trisodium salt of diethylenetriaminepentaacetic acid (Ca-DTPA) remains the chelating agent of choice for treatment of incorporated actinides. The zinc trisodium salt (Zn-DTPA) represents a less toxic alternative, when Ca-DTPA is contra-indicated as well as for prolonged chelation therapy; in acute incorporation cases it would be less effective than Ca-DTPA. Specific ion binding chelators such as desferrioxamine (DFOA) and linear tetracatechoylamides, e.g., LICAM(C) proved more effective in animals injected with Pu, Th and Np (not with Am!) but only concerning the radioactivity in the bone; that in the kidneys was substantially increased. The combinations of DFOA or LICAM(C) with Ca-DTPA exerted the best overall effects. After incorporation of soluble uranium-compounds, an infusion of sodium bicarbonate seems at present the most reasonable for enhancing the uranium-excretion and prevention of kidney damage. (author)

  7. Synthesis, characterization and in vitro anticancer evaluations of two novel derivatives of deferasirox iron chelator.

    Science.gov (United States)

    Salehi, Samie; Saljooghi, Amir Sh; Shiri, Ali

    2016-06-15

    Iron (Fe) chelation therapy was initially designed to alleviate the toxic effects of excess Fe evident in Fe-overload diseases. However, the novel toxicological properties of some Fe chelator-metal complexes have shifted significant attention to their application in cancer chemotherapy. The present study investigates the new role of deferasirox as an anticancer agent due to its ability to chelate with iron. Because of aminoacids antioxidant effect, deferasirox and its two novel amino acid derivatives have been synthesized through the treatment of deferasirox with DCC as well as glycine or phenylalanine methyl ester. All new compounds have been characterized by elemental analysis, FT-IR NMR and mass spectrometry. Therefore, the cytotoxicity of these compounds was screened for antitumor activity against some cell lines using cisplatin as a comparative standard by MTT assay and Flow cytometry. The impact of iron in the intracellular generation of reactive oxygen species was assessed on HT29 and MDA-MB-231 cells. The potential of the synthesized iron chelators for their efficacy to protect cells against model oxidative injury induced was compared. The reactive oxygen species intracellular fluorescence intensity were measured and the result showed that the reactive oxygen species intensity after iron incubation increased while after chelators incubation the reactive oxygen species intensity were decreased significantly. Besides, the effect of the synthesized compounds on mouse fibroblast cell line (L929) was simultaneously evaluated as control. The pharmacological results showed that deferasirox and its two novel aminoacid derivatives were potent anticancer agents. PMID:27090924

  8. Synthesis characterization and structural investigations on lanthanon(III) chelates of tridentate Schiff bases

    International Nuclear Information System (INIS)

    The dissociation constants of O-(N-pyrrole-2-methyl imino) propanoic acid [H2PP] and O-(N-furan-2-chloroimino)ethane thiol [HFT], stability constants and thermodynamic parameters of their chelates with La(II), Ce(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III), Ho(III) and Er(III) have been determined by Calvin-Bjerrum pH-titration techniques as modified by Irving and Rossotti in 30% (v/v) alcohol-water medium (μ=0.01 M, 0.05 M and 0.1 M NaClO4) at 25, 35 and 45degC. Solid Ln(III) chelates were characterized by molecular mass, elemental analysis, magnetic moment, conductance, 1H NMR, electronic and IR spectra. HFT-Ln(III)-chelates show 1:3 metal-ligand stoichiometry whereas H2PP-Ln(III)-chelates show 1:2 stoichiometry. Physico-chemical studies such as magnetic, IR, NMR etc. also support these geometries. HFT and H2PP are respectively monoprotic and biprotic tridentates. In view of the above facts a trigonal tricapped pyramidal and octahedral geometries can be assigned to the HFT-Ln(III) and H2PP-Ln(III) chelates respectively. (author). 15 refs., 4 tabs., 1 fig

  9. Crystal-structural study of zirconium chelates with alkali metals of composition A2[Zr(Nta)2]·xH2O (A=Li, Na, K, Rb, Cs or CH3H6)

    International Nuclear Information System (INIS)

    Some zirconium complexes with nitrile triacetate and with alkali metal in the external sphere were studied crystalostructurally. Packing of complexes and extra-sphere cations was studied. Plane or slightly corrugated anion layers of two essentially different types arranged according to the principle of trigonal and square grids represent the standard element of crystal structure. Water molecules are located both in anion and cation layers. CN and coordination polyhedron of cations are different even in case of stereotype nature of reasons of their location in the interlayer space. In Cs-, Rb- and K- compounds polyhedrons of alkali metal form specific doubled chains. These compounds are not isomorphous ones and are characterized by a specific way of water molecule location. Structure of sodium compound differs fundamentally from other ones. Ionic conductivity may be expected in crystals. 4 refs., 6 figs., 2 tabs

  10. Development of a dipodal Schiff base ligand with N-imine and O-naphtholate donors: A potential chelator towards Cu(II) metal ion established through potentiometric and spectrophotometric studies

    Energy Technology Data Exchange (ETDEWEB)

    Baral, Minati, E-mail: minatib@gmail.com; Gupta, Amit [Department of Chemistry, National Institute of Technology, Kurukshetra, Haryana (India); Kanungo, B. K. [Department of Chemistry, Sant Longowal Institute of Engineering and Technology, Longowal, Punjab (India)

    2015-08-28

    A novel hydroxynaphthaldehyde derived Schiff base ligand N,N’-bis-[2-[(2-hydroxy-1-naphthyl)methyleneamino]ethyl]propanediamide (DOTA2HNAP) containing nitrogen and oxygen donor atoms has been developed. The lowest energy molecular structure of DOTA2HNAP and its complexes with Cu (II) metal ion were examined by molecular mechanics using MM+ force which later was re-optimized by semi-empirical method. The theoretical IR and UV spectra of the ligand were obtained using semi empirical/ZINDO/PM3 and were compared with the experimental ones. The coordinating ability of DOTA2HNAP with H{sup +} and Cu(II) ions was investigated in 1:99 (DMSO: water) binary solvent mixture at 25±1°C by potentiometric and spectrophotometric method. The electronic spectra of the ligand show three distinct peaks (253nm, 320nm and 360nm) implicating existence of the Schiff base in quinone form that was well supported by theoretical spectral studies. Out of various complex species forming in solution, all the metal ions show higher stability of complexes when in 1:1 metal-ligand stoichiometry, binding through two N-imine and two O-naphtholate groups.

  11. Development of a dipodal Schiff base ligand with N-imine and O-naphtholate donors: A potential chelator towards Cu(II) metal ion established through potentiometric and spectrophotometric studies

    International Nuclear Information System (INIS)

    A novel hydroxynaphthaldehyde derived Schiff base ligand N,N’-bis-[2-[(2-hydroxy-1-naphthyl)methyleneamino]ethyl]propanediamide (DOTA2HNAP) containing nitrogen and oxygen donor atoms has been developed. The lowest energy molecular structure of DOTA2HNAP and its complexes with Cu (II) metal ion were examined by molecular mechanics using MM+ force which later was re-optimized by semi-empirical method. The theoretical IR and UV spectra of the ligand were obtained using semi empirical/ZINDO/PM3 and were compared with the experimental ones. The coordinating ability of DOTA2HNAP with H+ and Cu(II) ions was investigated in 1:99 (DMSO: water) binary solvent mixture at 25±1°C by potentiometric and spectrophotometric method. The electronic spectra of the ligand show three distinct peaks (253nm, 320nm and 360nm) implicating existence of the Schiff base in quinone form that was well supported by theoretical spectral studies. Out of various complex species forming in solution, all the metal ions show higher stability of complexes when in 1:1 metal-ligand stoichiometry, binding through two N-imine and two O-naphtholate groups

  12. Trypanotoxic activity of thiosemicarbazone iron chelators.

    Science.gov (United States)

    Ellis, Samuel; Sexton, Darren W; Steverding, Dietmar

    2015-03-01

    Only a few drugs are available for treating sleeping sickness and nagana disease; parasitic infections caused by protozoans of the genus Trypanosoma in sub-Saharan Africa. There is an urgent need for the development of new medicines for chemotherapy of these devastating diseases. In this study, three newly designed thiosemicarbazone iron chelators, TSC24, Dp44mT and 3-AP, were tested for in vitro activity against bloodstream forms of Trypanosoma brucei and human leukaemia HL-60 cells. In addition to their iron chelating properties, TSC24 and Dp44mT inhibit topoisomerase IIα while 3-AP inactivates ribonucleotide reductase. All three compounds exhibited anti-trypanosomal activity, with minimum inhibitory concentration (MIC) values ranging between 1 and 100 µM and 50% growth inhibition (GI50) values of around 250 nM. Although the compounds did not kill HL-60 cells (MIC values >100 µM), TSC24 and Dp44mT displayed considerable cytotoxicity based on their GI50 values. Iron supplementation partly reversed the trypanotoxic and cytotoxic activity of TSC24 and Dp44mT but not of 3-AP. This finding suggests possible synergy between the iron chelating and topoisomerase IIα inhibiting activity of the compounds. However, further investigation using separate agents, the iron chelator deferoxamine and the topoisomerase II inhibitor epirubicin, did not support any synergy for the interaction of iron chelation and topoisomerase II inhibition. Furthermore, TSC24 was shown to induce DNA degradation in bloodstream forms of T. brucei indicating that the mechanism of trypanotoxic activity of the compound is topoisomerase II independent. In conclusion, the data support further investigation of thiosemicarbazone iron chelators with dual activity as lead compounds for anti-trypanosomal drug development. PMID:25595343

  13. Monitoring the effects of chelating agents and electrical fields on active forms of Pb and Zn in contaminated soil.

    Science.gov (United States)

    Tahmasbian, Iman; Safari Sinegani, Ali Akbar

    2013-11-01

    The application of electrical fields and chelating agents is an innovative hybrid technology used for the decontamination of soil polluted by heavy metals. The effects of four center-oriented electrical fields and chelating agents on active fractions of lead and zinc were investigated in this pot experiment. Ethylenediaminetetraacetic acid (EDTA) as a synthetic chelator and cow manure extract (CME) and poultry manure extract (PME) as natural chelators were applied to the pots (2 g kg(-1)) 30 days after the first irrigation. Two weeks later, four center-oriented electrical fields were applied in each pot (in three levels of 0, 10, and 30 V) for 1 h each day for 14 days. The soil near the cathode and anodes was collected and analyzed as cathodic and anodic soil, respectively. Results indicated that the soluble-exchangeable fraction of lead and zinc were decreased in the cathodic soil, while the carbonate-bound fractions were increased. In the anodic soil, however, the opposite result was observed. EDTA enhanced the soluble-exchangeable form of the metals in both anodic and cathodic soils. Furthermore, the amounts of carbonate-bound heavy metals were increased by the application of CME in both soils. The organic-bound fraction of the metals was increased by the application of natural chelators, while electrical fields had no significant impacts on this fraction. PMID:23685981

  14. Recent developments centered on orally active iron chelators

    Directory of Open Access Journals (Sweden)

    Robert Hider

    2014-09-01

    Full Text Available Over the past twenty years there has been a growing interest in the orally active iron chelators, deferiprone and deferasirox, both have been extensively studied. The ability of these compounds to mobilize iron from the heart and endocrine tissue has presented the clinician with some advantages over desferrioxamine, the first therapeutic iron chelator. Other orally active iron chelators are currently under development. The critical features necessary for the design of therapeutically useful orally active iron chelators are presented in this review, together with recent studies devoted to the design of such chelators. This newly emerging range of iron chelators will enable clinicians to apply iron chelation methodology to other disease states and to begin to design personalized chelation regimes.

  15. Assessment of the Efficacy of Chelate-Assisted Phytoextraction of Lead by Coffeeweed (Sesbania exaltata Raf.

    Directory of Open Access Journals (Sweden)

    Gloria Miller

    2008-12-01

    Full Text Available Lead (Pb, depending upon the reactant surface, pH, redox potential and other factors can bind tightly to the soil with a retention time of many centuries. Soil-metal interactions by sorption, precipitation and complexation processes, and differences between plant species in metal uptake efficiency, transport, and susceptibility make a general prediction of soil metal bioavailability and risks of plant metal toxicity difficult. Moreover, the tight binding characteristic of Pb to soils and plant materials make a significant portion of Pb unavailable for uptake by plants. This experiment was conducted to determine whether the addition of ethylenediaminetetraacetic acid (EDTA, ethylene glycol tetraacetic acid (EGTA, or acetic acid (HAc can enhance the phytoextraction of Pb by making the Pb soluble and more bioavailable for uptake by coffeeweed (Sesbania exaltata Raf.. Also we wanted to assess the efficacy of chelates in facilitating translocation of the metal into the above-ground biomass of this plant. To test the effect of chelates on Pb solubility, 2 g of Pb-spiked soil (1000 mg Pb/kg dry soil were added to each 15 mL centrifuge tube. Chelates (EDTA, EGTA, HAc in a 1:1 ratio with the metal, or distilled deionized water were then added. Samples were shaken on a platform shaker then centrifuged at the end of several time periods. Supernatants were filtered with a 0.45 μm filter and quantified by inductively coupled plasma-optical emission spectrometry (ICP-OES to determine soluble Pb concentrations. Results revealed that EDTA was the most effective in bringing Pb into solution, and that maximum solubility was reached 6 days after chelate amendment. Additionally, a greenhouse experiment was conducted by planting Sesbania seeds in plastic tubes containing top soil and peat (2:1, v:v spiked with various levels (0, 1000, 2000 mg Pb/kg dry soil of lead nitrate. At six weeks after emergence, aqueous solutions of EDTA and/or HAc (in a 1:1 ratio

  16. Development of an upconverting chelate assay

    Science.gov (United States)

    Xiao, Xudong; Haushalter, Jeanne P.; Kotz, Kenneth T.; Faris, Gregory W.

    2005-04-01

    We report progress on performing a cell-based assay for the detection of EGFR on cell surfaces by using upconverting chelates. An upconversion microscope has been developed for performing assays and testing optical response. A431 cells are labeled with europium DOTA and imaged using this upconverting microscope.

  17. Questions and Answers on Unapproved Chelation Products

    Science.gov (United States)

    ... it Email Print The U.S. Food and Drug Administration (FDA) advises consumers to be wary of so-called “chelation” products that are marketed over-the-counter (OTC) to prevent or treat diseases. Companies are marketing unapproved OTC chelation therapy products to ...

  18. Overview of chelation recommendations for thalassaemia and sickle cell disease

    OpenAIRE

    Banu Kaya

    2014-01-01

    The long term consequences of iron toxicity are mostly reversible with effective iron chelation therapy. Recommendations for use of chelation therapy in transfusion dependent thalassaemia (TDT), sickle cell disease (SCD) and non transfusion dependent thalassaemia (NTDT) continue to evolve as our knowledge and clinical experience increases. Improved chelation options including drug combinations and a better understanding of condition specific factors may help to improve efficiency of chelation...

  19. Overview of chelation recommendations for thalassaemia and sickle cell disease

    Directory of Open Access Journals (Sweden)

    Banu Kaya

    2014-12-01

    Full Text Available The long term consequences of iron toxicity are mostly reversible with effective iron chelation therapy. Recommendations for use of chelation therapy in transfusion dependent thalassaemia (TDT, sickle cell disease (SCD and non transfusion dependent thalassaemia (NTDT continue to evolve as our knowledge and clinical experience increases. Improved chelation options including drug combinations and a better understanding of condition specific factors may help to improve efficiency of chelation regimens and meet the needs of patients more effectively.

  20. Chelating water-soluble polymers for waste minimization

    International Nuclear Information System (INIS)

    Within the DOE complex and in industry there is a tremendous need for advanced metal ion recovery and waste minimization techniques. This project sought to employ capabilities for ligand-design and separations chemistry in which one can develop and evaluate water- soluble chelating polymers for recovering actinides and toxic metals from various process streams. Focus of this work was (1) to develop and select a set of water-soluble polymers suitable for a selected waste stream and (2) demonstrate this technology in 2 areas: removal of (a) actinides and toxic RCRA metals from waste water and (b) recovery of Cu and other precious metals from industrial process streams including from solid catalysts and aqueous waste streams. The R ampersand D was done in 4 phases for each of the 2 target areas: polymer synthesis for scaleup, equipment assembly, process demonstration at a DOE or industrial site, and advanced ligand/polymer synthesis. The TA- 50 site at Los Alamos was thought to be appropriate due to logistics and to its being representative of similar problems throughout the DOE complex

  1. Disaggregation ability of different chelating molecules on copper ion-triggered amyloid fibers.

    Science.gov (United States)

    Zhu, Linyi; Han, Yuchun; He, Chengqian; Huang, Xu; Wang, Yilin

    2014-08-01

    Dysfunctional interaction of amyloid-β (Aβ) with excess metal ions is proved to be related to the etiology of Alzheimer's disease (AD). Using metal-binding compounds to reverse metal-triggered Aβ aggregation has become one of the potential therapies for AD. In this study, the ability of a carboxylic acid gemini surfactant (SDUC), a widely used metal chelator (EDTA), and an antifungal drug clioquinol (CQ) in reversing the Cu(2+)-triggered Aβ(1-40) fibers have been systematically studied by using turbidity essay, BCA essay, atomic force microscopy, transmission electron microscopy, and isothermal titration microcalorimetry. The results show that the binding affinity of Cu(2+) with CQ, SDUC, and EDTA is in the order of CQ > EDTA > SDUC, while the disaggregation ability to Cu(2+)-triggered Aβ(1-40) fibers is in the order of CQ > SDUC > EDTA. Therefore, the disaggregation ability of chelators to the Aβ(1-40) fibers does not only depend on the binding affinity of the chelators with Cu(2+). Strong self-assembly ability of SDUC and π-π interaction of the conjugate group of CQ also contributes toward the disaggregation of the Cu(2+)-triggered Aβ(1-40) fibers and result in the formation of mixed small aggregates. PMID:25051063

  2. Water-soluble chelating polymers for removal of actinides from watewater

    Energy Technology Data Exchange (ETDEWEB)

    Jarvinen, G. [Los Alamos National Lab., NM (United States)

    1996-10-01

    Polymer filtration is a technology being developed to recover valuable or regulated metal ions selectively from process or wastewaters. Water-soluble chelating polymers are specially designed to bind selectively with metal ions in aqueous solutions. The polymers molecular weight is large enough so they can be separated and concentrated using available ultrafiltration technology. Water and smaller unbound components of the solution pass freely through the ultrafiltration membrane. The polymers can then be reused by changing the solution conditions to release the metal ions, which are recovered in concentrated form, for recycle or disposal.

  3. 金属螯合剂对延边黄牛体细胞核移植重组胚发育的影响%Effects of metal-chelator on the in vitro development of reconstructed embryos cloned from somatic cell of Yanbian yellow cattle

    Institute of Scientific and Technical Information of China (English)

    尹多; 柳海星; 李钟淑; 许相勋; 方南洙

    2012-01-01

    In the experiment of somatic cell nuclear transfer(SCNT),the pollution of some kinds of metal ions can't be avoided from the water and chemical substance used.It seemed difficult to keep the balance between perhydride and antioxidant in embryo with metal ions,which cuts down the embryo developmental rate.Based on this point,in present study two kinds of metal-chelator antioxidant,EDTA-Na and sodium citrate,were added in the early culture medium for embryos cloned from somatic cell of Yanbian yellow cattle,and the effects of them on the subsequent development of these embryos were discussed to define the best condition of in vitro culture.The results indicated that the suitable concentrations of EDTA-Na and sodium citrate for the developmental competence of embryos cloned from somatic cell of Yanbian yellow cattle were 50 μmol/L and 0.6 mmol/L,respectively.%由于在核移植试验中,所用的水和化学物质都不可避免的会被一些金属离子轻微污染,造成胚胎内抗氧化物和过氧化物之间难以保持平衡,从而导致胚胎发育率降低,本试验以此为出发点,探讨了在延边黄牛体细胞核移植重组胚早期培养液中添加乙二胺四乙酸钠(EDTA-Na)和柠檬酸钠(sodium citrate)2种金属螯合剂类抗氧化剂,对其后续发育的影响,以期筛选出最佳的体外培养条件。结果表明:适合延边黄牛体细胞核移植重组胚后期发育的EDTA-Na和柠檬酸钠的最佳浓度分别为50μmol/L和0.6mmol/L。

  4. Effects of Chelators on the Uptake of Heavy Metals by Solanum nigrum and Pteris cretica var. Nervosa Growing in an Intercropping System%间作条件下螯合剂对龙葵和大叶井口边草吸收重金属的影响

    Institute of Scientific and Technical Information of China (English)

    熊国焕; 高建培; 王宏镔; 潘义宏; 焦鹏

    2011-01-01

    Enhancing phytoextraction of heavy metals has been proposed as an effective approach to remove heavy metals from contaminated soils. Plants with different metal-hyperaccumulative characteristics, namely Solanum nigrum and Pteris cretica var. nervosa, were monocropped or intercropped in multiple-metal contaminated field soils in this study. This line of study aims to investigate, compared with monocropping method, whether intercropping method could improve metal uptake by these two tested plants. The effects of ethylene diamine disuccinate (EDDS), ethylene diamine tetraacetate (EDTA) and nitrilotriacetic acid (NTA) on uptake of heavy metals (Pb, Cd and As) by plants growing in an intercropping system were also investigated using the same soil. Compared with monocropping method, intercropping method increased Cd concentration 1.3 times and As concentration 1.4 times in shoots of S.nigrum and P. cretica var. nervosa, respectively.This result indicated that intercropping method could significantly improve heavy metal uptake by hyperaccumulators. Much higher tolerance to chelators was observed in P. cretica var. nervosa than that in S. nigrum in the intercropping system. The application of 3, 6, 12 mmol· kg-1 EDTA to soil contaminated with heavy metals significantly increased soil Pb, Cd bioavailability and concentrations of Pb in two intercropped plants. The maximum Pb concentrations reached 27.58 mg ·kg-1 and 26.17 mg ·kg-1 in S. nigrum and P. cretica var. nervosa, respectively,which were 3.3 times and 3 times higher than that in the corresponding control plants to which no chelators were applied. Under the conditions of the intercropping system, the application of 3, 6, 12 mmol· kg-1 EDTA also significantly increased Cd concentration in the shoot of P.cretica var. nervosa. EDTA was more effective than NTA in increasing soil Pb, Cd bioavailability, but was less effective than NTA in increasing soil As bioavailability. The application of 1.5 mmol· kg-1 and 3 mmol

  5. Influence of Chelating Agents on Chromium Fate in Sediment

    Institute of Scientific and Technical Information of China (English)

    WANGXIAOCHANG; SUNJINHE; 等

    1996-01-01

    A laboratory investigation on reaction between chelating agents and chromium was conducted to evaluate the effect of chelating agents on the adsorption and desorption of chromium in sediment.The amount of adsorbed chromium(VI) in sediment decreased slightly by 5%-10% because of addition of chelating agents.Chelating agents inhibited the removal of Cr(Ⅲ)by sediment from solutions and the inhibiting effect was in the order:citric acid>tartaric acid>EDTA,Salicylic acid.No effect of chelating agents on desorption of chromium in sediment was observed.

  6. Immunoreactivity and Radioimmunoscintigraphy of 4-Lysine Single Chain (Fv) Lym-1 Antibody for the Radiometal Chelation

    International Nuclear Information System (INIS)

    Small size of recombinant scFv, composed of VH and VL region of IgG, has many advantages such as faster blood clearance, improved tumor localization and reduced human anti-mouse antibody (HAMA) response. On the other hand, owing to small size, number of amino group, which was not involved in binding site, of ScFv lym-1 was insufficient in conjugation with CITC-DTPA chelator for radio metal labeling. The goal of this study is to introduce 4-lysine tag to the end of ScFv lym-1 sequence for radio metal conjugation and to evaluate the immunoreactivity and radioimmunoscintigraphy of chelator conjugated 4-lysine taq scFv lym-1 (4-lys scFv)

  7. Pentaarylcyclopentadiene und chirale Ruthenium-Chelat-Komplexe

    OpenAIRE

    Kanthak, Matthias

    2010-01-01

    Die Synthese von mono-ortho-funktionalisierten Pentaphenylcyclopentadienen gelang durch eine Abwandlung der klassischen Tetracyclon-Route. Durch die Umsetzung der funktionalisierten Cyclopentadiene mit Ru3(CO)12 als Metallquelle konnten entsprechende Ruthenium-Komplexe erhalten werden. Die geeignete Wahl der Substituenten an der Phenylgruppe erlaubte die Bildung von Chelat-Komplexen mit chirotopem Metallzentrum. Enantiomerenreine Oxazolin-Seitenarme führten zu diastereomerenreinen...

  8. EDTA: the chelating agent under environmental scrutiny

    OpenAIRE

    Claudia Oviedo; Jaime Rodríguez

    2003-01-01

    The chelating agent EDTA (ethylenediaminetetraacetic acid) is a compound of massive use world wide with household and industrial applications, being one of the anthropogenic compounds with highest concentrations in inland European waters. In this review, the applications of EDTA and its behavior once it has been released into the environment are described. At a laboratory scale, degradation of EDTA has been achieved; however, in natural environments studies detect poor biodegradability. It is...

  9. Quantification of thorium in uranium matrix by chelation ion chromatography (CIC)

    International Nuclear Information System (INIS)

    The present work describes an optimized procedure for the determination of thorium in uranium oxide by chelation ion chromatography technique. The method involves a two stage separation of matrix element by employing solvent extraction and ion exchange. Chromatographically thorium has been separated from the traces of other metallic impurities and the matrix element which is expected to be present in trace quantity even after employing prior separations. (author)

  10. Theoretical study, and infrared and Raman spectra of copper(II) chelated complex with dibenzoylmethane

    DEFF Research Database (Denmark)

    Nekoei, A.-R.; Vakili, M.; Hakimi-Tabar, M.;

    2014-01-01

    There are some discrepancies in both the vibrational assignments and in the metal-ligand (M-L) bond strengths predicted in the previous studies on the copper (II) chelated complex of dibenzoylmethane, Cu(dbm)2. Also, there is a lack of theoretical structure, Raman spectrum and full vibrational as...... in Cu(dbm)2 are concluded to be higher than those in Cu(acac)2. The calculated geometries and vibrational results are in good agreement with the experimental data....

  11. Curcumin Inhibits Growth of Saccharomyces cerevisiae through Iron Chelation ▿ ††

    OpenAIRE

    Minear, Steven; O'Donnell, Allyson F.; Ballew, Anna; Giaever, Guri; Nislow, Corey; Stearns, Tim; Martha S Cyert

    2011-01-01

    Curcumin, a polyphenol derived from turmeric, is an ancient therapeutic used in India for centuries to treat a wide array of ailments. Interest in curcumin has increased recently, with ongoing clinical trials exploring curcumin as an anticancer therapy and as a protectant against neurodegenerative diseases. In vitro, curcumin chelates metal ions. However, although diverse physiological effects have been documented for this compound, curcumin's mechanism of action on mammalian cells remains un...

  12. Chelator-Induced Dispersal and Killing of Pseudomonas aeruginosa Cells in a Biofilm†

    OpenAIRE

    Banin, Ehud; Brady, Keith M.; Greenberg, E. Peter

    2006-01-01

    Biofilms consist of groups of bacteria attached to surfaces and encased in a hydrated polymeric matrix. Bacteria in biofilms are more resistant to the immune system and to antibiotics than their free-living planktonic counterparts. Thus, biofilm-related infections are persistent and often show recurrent symptoms. The metal chelator EDTA is known to have activity against biofilms of gram-positive bacteria such as Staphylococcus aureus. EDTA can also kill planktonic cells of Proteobacteria like...

  13. IRON CHELATION THERAPY IN THALASSEMIA SYNDROMES

    Directory of Open Access Journals (Sweden)

    Paolo Cianciulli

    2009-06-01

    Full Text Available Transfusional hemosiderosis is a frequent complication in patients with transfusion dependent chronic diseases such as  thalassemias and severe type of sickle cell diseases. As there are no physiological mechanisms to excrete the iron contained in transfused red cells (1 unit of blood contains approximately 200 mg of iron the excess of iron is stored in various organs. Cardiomyopathy is the most severe complication covering more than 70% of the causes of death of thalassemic patients. Although the current reference standard iron chelator deferoxamine (DFO has been used clinically for over four decades, its effectiveness is limited by a demanding therapeutic regimen that leads to poor compliance. Despite poor compliance, because of the inconvenience of subcutaneous infusion, DFO improved considerably the survival and quality of life of patients with thalassemia. Deferiprone since 1998 and Deferasirox since 2005 were licensed for clinical use. The oral chelators have a better compliance because of oral use, a comparable efficacy to DFO in iron excretion and probably a better penetration to myocardial cells. Considerable increase in iron excretion was documented with combination therapy of DFO and Deferiprone. The proper use of the three chelators will improve the prevention and treatment of iron overload, it will reduce  complications, and improve survival and quality of life of transfused patients

  14. Antioxidant and Chelating Activity of Nontoxic Jatropha curcas L. Protein Hydrolysates Produced by In Vitro Digestion Using Pepsin and Pancreatin

    Directory of Open Access Journals (Sweden)

    Santiago Gallegos Tintoré

    2015-01-01

    Full Text Available The antioxidant and metal chelating activities in J. curcas protein hydrolysates have been determined. The hydrolysates were produced by treatment of a nontoxic genotype with the digestive enzymes pepsin and pancreatin and then were characterized by fast protein liquid chromatography and reverse phase chromatography. Peptidic fractions with higher radical scavenging activity were analysed by matrix-assisted laser desorption/ionization mass spectrometry. The antioxidant activity was determined by measuring inhibition of the oxidative degradation of β-carotene and by measuring the reactive oxygen species (ROS in Caco-2 cell cultures. Cu2+ and Fe2+ chelating activities were also determined. The hydrolysates inhibited the degradation of β-carotene and the formation of ROS in Caco-2 cells. The lower molecular weight peptidic fractions from FPLC had stronger antioxidant activity in cell cultures compared with the hydrolysates, which correlated with a higher content in antioxidant and chelating amino acids. These fractions were characterized by a large presence of peptides with different molecular masses. The hydrolysates exhibited both Cu2+ and Fe2+ chelating activity. It was concluded that J. curcas is a good source of antioxidant and metal chelating peptides, which may have a positive impact on the economic value of this crop, as a potential source of food functional components.

  15. [Remediation of Cu-Pb-contaminated loess soil by leaching with chelating agent and biosurfactant].

    Science.gov (United States)

    Liu, Xia; Wang, Jian-Tao; Zhang, Meng; Wang, Li; Yang, Ya-Ti

    2013-04-01

    Because of its strong chelation, solubilization characteristics, the chelating agents and biosurfactant are widely used in remediation of heavy metals and organic contaminated soils. Ethylenediamine tetraacetic acid (EDTA), citric acid (CIT) and dirhamnolipid (RL2) were selected as the eluent. Batch experiments and column experiments were conducted to investigate the leaching effect of the three kinds of eluent, as well as the mixture of biosurfactant and chelating agent for Cu, Pb contaminated loess soil. The results showed that the leaching efficiencies of different eluent on Cu, Pb contaminated loess soil followed the sequence of EDTA > CIT > RL2. At an eluent concentration of 0.02 mol x L(-1), the Cu leaching efficiency was 62.74% (EDTA), 52.28% (CIT) and 15.35% (RL2), respectively; the Pb leaching efficiency was 96.10% (EDTA), 23.08% (CIT) and 14.42% (RL2), respectively. When the concentration of RL2 was 100 CMC, it had synergistic effects on the other two kinds of chelating agent in Cu leaching, and when the concentration of RL2 was 200 CMC, it had antagonism effects. The effect of RL2 on EDTA in Pb leaching was similar to that in Cu leaching. Pb leaching by CIT was inhibited in the presence of RL2. EDTA and CIT could effectively remove Cu and Pb in exchangeable states, adsorption states, carbonate salts and organic bound forms; RL2 could effectively remove Cu and Pb in exchangeable and adsorbed states. PMID:23798147

  16. The Mechanism of Cumene Peroxidation Catalyzed by Cobalt(Ⅱ)-Chelated Copolymer

    Institute of Scientific and Technical Information of China (English)

    Cheng-Chien Wang; Hui-Chun Chen; Chuh-Yean Chen; Chuh-Yung Chen

    2005-01-01

    @@ 1Introduction The functionalised polymers, especially for chelating polymer, have been employed to considerable effects in organic synthesis for several decades. The use of polymer groups as ligands permits the ligand surroundings to be varied and regulation of the catalytic properties of the complexes because of the flexibility of the polymer chains, their ability to adopt various conformations, and the possibility of creating various spatial distributions of metal centers immobilized on the polymer chains[1,2]. In our recently studies[3-5], the chelating copolymer with imino-diacetic acid chelating group in the polymer side chain was manufactured, and which can increase effectively amount of the chelating group within the polymer. Meanwhile, the high catalysis performance in organic synthesis had also been proved via benzaldehyde and cumene peroxidation. For cumene peroxidation,it is hardly to find such a simple catalyst with high conversion and selectivity due to hydroperoxide decomposition by a radical mechanism. The cumene peroxidation by catalyst system and its reaction mechanism as well as the kinetic study are popularly investigated object for many researchers[6-9]. However, the reaction mechanism still does not clear owing to the by-products will be produced following the different catalysts used.

  17. Isolation and Utilization of Corn Cobs Hemisellulose as Chelating Agent for Lead Ions

    International Nuclear Information System (INIS)

    Corn cobs is an agricultural byproduct containing polysaccharide composed of cellulose, hemicelluloses and lignin. Hemicelluloses has a hydroxyl and carbonyl functional groups which can be used as chelating agent for metal ions. The purpose of this study was to isolate and evaluate corncobs hemicelluloses as a chelating agent toward lead ion. Graphite furnace spectrophotometry at 283.3 nm was used to determine the residual lead ion in solution. The research's result showed that the highest yield of hemicelluloses (12.04 %) was obtained from delignication with 0,03 M NaOH in 60 % ethanol and 3 % H2O2, hemicelluloses isolation with 500 ml of 0.2 M NaOH, and precipitation with 1:4 ratio of 10 % acetic acid in 95 % ethanol. The 300 mg corn cobs hemicelluloses has chelating effect for 40 mg lead solution at (39.52±0.1350) mg or 98.80 %, that the corn cobs hemicelluloses can be used as a chelating agent for lead. (author)

  18. Composition and stability of Nb(V), Zr(IV), Y(III) and La(III) chelates with 7-nitroso-8-quinolinone-5-sulphonate

    International Nuclear Information System (INIS)

    New Nb(V), Zr(IV), Y(III) and La(III) chelates obtained from disodium salt of 7-nitroso-8-quinolinole-5-sulphonic acid were studied using spectrophotometric, conductimetric and potentiometric methods. The solid chelates were synthesized and their ir spectra and elemental analysis were discussed. The ligand is bonded to the metal ion through the oxygens of nitroso and hydroxy groups. The apparent stability constants of the complexes formed in solution were also determined spectrophotometrically and potentiometrically

  19. Synthesis and polarographic study of Ni(2), Zn(2), and Cd(2) chelates with 3-nitro-1,2,4-triazole

    International Nuclear Information System (INIS)

    Chelate compounds of Ni(2), Zn(2) and Cd(2) with 3-nitro-1,2,4-triazole (NTR) have been prepared. Th electroreduction of NTR in aqueous solutions and dimetilformamide of various concentrations at pH 1.7-9.5 has been studied with the help of polarographic method. It is shown that quantitative determination of NTR and the metalls studied from one sample of chelates is possible with the use of polarographic method

  20. Continuous Remediation of Heavy Metal Contaminated Soil by Co-Cropping System Enhanced with Chelator%植物套种及化学强化对重金属污染土壤的持续修复效果研究

    Institute of Scientific and Technical Information of China (English)

    卫泽斌; 郭晓方; 吴启堂; 龙新宪

    2014-01-01

    In order to elucidate the continuous effectiveness of co-cropping system coupling with chelator enhancement in remediating heavy metal contaminated soils and its environmental risk towards underground water, soil lysimeter (0. 9 m × 0. 9 m × 0. 9 m) experiments were conducted using a paddy soil affected by Pb and Zn mining in Lechang district of Guangdong Province, 7 successive crops were conducted for about 2. 5 years. The treatments included mono-crop of Sedum alfredii Hance ( Zn and Cd hyperaccumulator), mono-crop of corn (Zea mays, cv. Yunshi-5, a low-accumulating cultivar), co-crop of S. alfredii and corn, and co-crop + MC (Mixture of Chelators, comprised of citric acid, monosodium glutamate waste liquid, EDTA and KCl with molar ratio of 10: 1: 2: 3 at the concentration of 5 mmol·kg - 1 soil). The changes of heavy metal concentrations in plants, soil and underground water were monitored. Results showed that the co-cropping system was suitable only in spring-summer seasons and significantly increased Zn and Cd phytoextraction. In autumn-winter seasons, the growth of S. alfredii and its phytoextraction of Zn and Cd were reduced by co-cropping and MC application. In total, the mono-crops of S. alfredii recorded a highest phytoextraction of Zn and Cd. However, the greatest reduction of soil Zn, Cd and Pb was observed with the co-crop + MC treatment, the reduction rates were 28% , 50% , and 22% , respectively, relative to the initial soil metal content. The reduction of this treatment was mainly attributed to the downwards leaching of metals to the subsoil caused by MC application. The continuous monitoring of leachates during 2. 5 year's experiment also revealed that the addition of MC increased heavy metal concentrations in the leaching water, but they did not significantly exceed the III grade limits of the underground water standard of China.%为了研究植物套种和螯合剂施用对重金属污染土壤的长期修复效果以及对地下水可能的

  1. Lipophilic aroylhydrazone chelator HNTMB and its multiple effects on ovarian cancer cells

    Directory of Open Access Journals (Sweden)

    Singh Rakesh K

    2010-02-01

    Full Text Available Abstract Background Metal chelators have gained much attention as potential anti-cancer agents. However, the effects of chelators are often linked solely to their capacity to bind iron while the potential complexation of other trace metals has not been fully investigated. In present study, we evaluated the effects of various lipophilic aroylhydrazone chelators (AHC, including novel compound HNTMB, on various ovarian cancer cell lines (SKOV-3, OVCAR-3, NUTU-19. Methods Cell viability was analyzed via MTS cytotoxicity assays and NCI60 cancer cell growth screens. Apoptotic events were monitored via Western Blot analysis, fluorescence microscopy and TUNEL assay. FACS analysis was carried out to study Cell Cycle regulation and detection of intracellular Reactive Oxygen Species (ROS Results HNTMB displayed high cytotoxicity (IC50 200-400 nM compared to previously developed AHC (oVtBBH, HNtBBH, StBBH/206, HNTh2H/315, HNI/311; IC50 0.8-6 μM or cancer drug Deferoxamine, a hexadentate iron-chelator (IC50 12-25 μM. In a NCI60 cancer cell line screen HNTMB exhibited growth inhibitory effects with remarkable differences in specificity depending on the cell line studied (GI50 10 nM-2.4 μM. In SKOV-3 ovarian cancer cells HNTMB treatment led to chromatin fragmentation and activation of the extrinsic and intrinsic pathways of apoptosis with specific down-regulation of Bcl-2. HNTMB caused delayed cell cycle progression of SKOV-3 through G2/M phase arrest. HNTMB can chelate iron and copper of different oxidation states. Complexation with copper lead to high cytotoxicity via generation of reactive oxygen species (ROS while treatment with iron complexes of the drug caused neither cytotoxicity nor increased ROS levels. Conclusions The present report suggests that both, non-complexed HNTMB as a chelator of intracellular trace-metals as well as a cytotoxic HNTMB/copper complex may be developed as potential therapeutic drugs in the treatment of ovarian and other

  2. Mechanisms of oxide dissolution by acid chelating agents

    International Nuclear Information System (INIS)

    In this paper, the different possible rate controlling processes in the dissolution of metallic oxides are examined. In particular, the following situations are assessed: mass-transfer control; coupling of mass-transfer and reactions at the interface; interface equilibration with the solution; various interface disruption and reconstruction phenomena. For each of the above mentioned cases, the influence of variables such as reagent concentration, temperature, pH, fluid hydrodynamics and general and specific catalysts is discussed. Depending upon the particular situation it is found that a more rational basis for the development of reagent is given by these considerations. The influence of chelating agents on both the thermodynamics and kinetics of the process is discussed, and the results of experimental studies in batch on magnetite and various ferrites are presented and discussed. For this purpose, several reagents were studied, including some very effective ones like thioglycolic acid, and others commonly used in actual decontamination, like ethylenediaminetetraacetic acid and oxalic acid. The relation to other (reductive) chemical decontamination procedures is discussed. The relevance of these studies to decontamination of metallic surfaces is discussed

  3. Mono- or bis-ligand complexes are better for chelation therapy? Theoretical approaches

    Science.gov (United States)

    Jakusch, Tamás; Kiss, Tamás

    2014-10-01

    In our theorethical approach we would like to point out that the dissociation constant (Kd value) of the complexes itself not enough parameter to describe the metal ion binding ability of the MPACS. The ligand concentration dependence of the free metal ion concentration is stronger is bis- or tris complexes are also formed (second or third order), than just mono complex (first order) exists, the theoretical therapeutic window should be more wide for tetra- penta- or hexadentate ligands (only mono complexes formed) than for bi- or tridentate chelators (bis- and tris complex formation is possible).

  4. Metal Chelation in Asymmetric Diels-Alder Reaction (II)

    International Nuclear Information System (INIS)

    In the reaction, the inverse asymmetric induction has been observed by the use of either monovalent Lewis acids or divalent Lewis acids. The reaction of the acrylate of (S)-ethyl lactate with cyclopentadiene proceeded with 86% endo-S selectivity in the presence of TiCl4, divalent Lewis acid, whereas did with 32% endo-R selectivity in the presence of BF3·Et2O, monovalent Lewis acid. When a chiral dienophile which was prepared from benzyl ester of (S)-proline or methyl ester of (S)-indoline-2-carboxylic acid was employed in the reaction, a similar diastereofacial selectivity was also observed. Recently, we reported the similar selectivity in the reaction of methyl (2S,5S)-(5-t-butyldimethylsilyloxypiperidin- 2-yl)ethanoatewith cyclopentadiene.

  5. Modern problems of chelate water conditions for TPPs and NPPs

    International Nuclear Information System (INIS)

    Review of investigations devoted to the application of chelate water conditions for TPPs and NPPs is given. Chelates (mainly EDTA and its salts) are used for increasing corrosion resistance of steels, operation and pre-start-up chemical purifications, correction of water conditions and coolant circuit purification under operation (without shutdown). It is stressed that under certain conditions the optimal continuous chelate water conditions are possible under water conditions are possible under which deposits are not produced

  6. Trypanotoxic activity of thiosemicarbazone iron chelators

    OpenAIRE

    Ellis, Samuel; Sexton, Darren; Steverding, Dietmar

    2015-01-01

    Only a few drugs are available for treating sleeping sickness and nagana disease; parasitic infections caused by protozoans of the genus Trypanosoma in sub-Saharan Africa. There is an urgent need for the development of new medicines for chemotherapy of these devastating diseases. In this study, three newly designed thiosemicarbazone iron chelators, TSC24, Dp44mT and 3-AP, were tested for in vitro activity against bloodstream forms of T. brucei and human leukaemia HL-60 cells. In addition to t...

  7. Novel Terbium Chelate Doped Fluorescent Silica Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Ning Qiaoyu; Meng Jianxin; Wang Haiming; Liu Yingliang; Man Shiqing

    2006-01-01

    Novel terbium chelate doped silica fluorescent nanoparticles were prepared and characterized.The preparation was carried out in water-in-oil (W/O) microemulsion containing monomer precursor (pAB-DTPAA-APTEOS), Triton X-100, n-hexanol, and cyclohexane by controlling copolymerization of tetraethyl orthosilicate and 3-aminopropyl-triethyloxysilane.The nanoparticles are spherical and uniform in size, about 30 nm in diameter, strongly fluorescent, and highly stable.The amino groups directly introduced to the surface of the nanoparticles using APTEOS during preparation made the surface modification and bioconjugation of the nanoparticles easier.The nanoparticles are expected as an efficient time-resolved luminescence biological label.

  8. Plutonium-237: comparative uptake in chelated and non-chelated form by channel catfish (Ictalurus punctatus)

    International Nuclear Information System (INIS)

    Chelation can either enhance or reduce the uptake of ingested plutonium relative to PuOH (monomer) in channel catfish. Reduced uptake of 237Pu-fulvate is due either to the molecular weight of the complex or its stability in metabolic systems. Increased uptake of 237Pu-citrate is attributable to instability of the complex in metabolic systems. (author)

  9. Physico-chemical studies on the chelation behaviour of biologically active 2-hydroxy-1-naphthaldehyde semicarbazone (HNAS) with some lanthanons

    International Nuclear Information System (INIS)

    The chelation behaviour of the complexes of La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Y3+, Tb3+, Dy3+, Ho3+ with biologically active 2-hydroxy-1-naphthaldehyde semicarbazone (HNAS) has been studied potentiometrically in 75% (v/v) dioxane-water medium at various ionic strenghts. The method of Bjerrum and Calvin, as modified by Irving and Rossotti has been used to find out the values of n-bar and pL. The formation constants of metal chelates and the values of Smin have been calculated. The order of formation constants of chelates was found to be: La3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+. (authors)

  10. Studies on In-situ Chelation/Supercritical Fluid Extraction of Lanthanides and Actinides Using a Radiotracer Technique

    International Nuclear Information System (INIS)

    Radioisotope tracer techniques were used to study the process of in-situ chelation/supercritical fluid extraction(SFE) of La3+ and Lu3+ from solid matrix using mixed ligand hexafluoroacetylacetone (HFA) and tributylphosphate (TBP) as chelating agents. A lab-built SFE extactor was used in this study and the extractor design was optimized based on the experimental results. Quantitative recovery of La and Lu was achieved when the extrator design was optimized. Extraction of uranium from real world samples was also investigated to demonstrate the capability of this chelation/SFE technology for environmental remediation applications. A novel on-line back extraction technique for the recovery of metal ions and regeneration of ligands is also reported.

  11. TEM and SEM observation of uranium induced renal necrosis and the result of chelates treatment on rats

    International Nuclear Information System (INIS)

    The TEM (transmission electron microscope) and SEM (scanning electron microscope) observation of uranium induced renal necrosis and the result of chelates treatment on rats are reported. Ultrastructural changes in kidney related with the impairment of intracellular fluid transportation can be found after acute uranium intoxication in rats, such as: condensation and swelling of mitochondria, matrix edema, dilatation of intercellular space, disappearance of basal folds, thickening of basal web, intensification of basal lamina of the proximal convoluted tubule epithelium cells, and foot processes swelling, diminishing of endothelium fenestrae of the renal glomerulus. Heavy metal chelates DTPA and H-73-10 treatment may result in intracellular fluid accumulation and condensed grannule formation in lysosome. Treatment with these chelates in the critical stage of uranium intoxication may accelerate the necrosis instead of diminishing. This may be related to the augment of the load of lysosome and intracellular system of fluid transportation

  12. Potentiometric, spectroscopic, electrochemical and DFT characterization of oxovanadium(IV) complexes formed by citrate and tartrates in aqueous solution at high ligand to metal molar ratios: the effects of the trigonal bipyramidal distortion in bis-chelated species and biological implications.

    Science.gov (United States)

    Lodyga-Chruscinska, Elzbieta; Sanna, Daniele; Garribba, Eugenio; Micera, Giovanni

    2008-09-28

    The complexation of VO(IV) ion with citrate (L3-), D-, L- and DL-tartrate (L2-) at high ligand to metal molar ratios was studied in aqueous solution through the combined application of potentiometric, spectroscopic (UV-vis and EPR) and electrochemical (cyclic voltammetry) techniques. Unlike in equimolar solution, mononuclear and not dinuclear species are formed with the binding of carboxylate-COO- and alcoholate-O- donors yielding mono- and bis-chelated species with VOLH, VOL, VOLH(-1) and VOL2H(-2) composition; for tartrates also the "sugar-like" (O-, O-) coordination is involved in the vanadium binding at basic pH values giving rise to the formation of VOL2H(-3) and VOL2H(-4) complexes. Among the species formed, VOL2H(-2) is characterised by a strong distortion towards the trigonal bipyramid with the two V-O(alcoholate) bonds in the equatorial and the two V-O(carboxylate) bonds in the axial positions. The geometry and electronic absorption spectra of such complexes were simulated by DFT methods and it was found that in aqueous solution the distortion follows the steric hindrance of the substituents on the alpha-carbon atom and the hydrophobicity of the ligands. The results were compared with those displayed by simple alpha-hydroxycarboxylates (glycolate, 2-hydroxyisobutyrate, 2-ethyl-2-hydroxybutyrate and benzilate). The trigonal bipyramidal distortion was correlated with the values of: i) Deltalambda = lambda2-lambda3, where lambda2 and lambda3 are the central bands in the electronic absorption spectrum; ii) |A(x)-A(y)|, where A(x) and A(y) are the 51V hyperfine coupling constants along the x and y axes in the anisotropic EPR spectrum; iii) the half-wave potential E(1/2) of oxidation of VO(IV) to the corresponding VO2(V) species in the cyclic voltammogram. Finally, a discussion on the possible form of VO(IV)-citrate complexes in blood serum is presented, where it is found that the most relevant species under physiological conditions should be [VO(citrH(-1

  13. Water-soluble chelating polymers for removal of actinides from wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Jarvinen, G.D. [Los Alamos National Lab., NM (United States)

    1997-10-01

    Polymer filtration is a technology under development to selectively recover valuable or regulated metal ions from process or wastewaters. The technology uses water-soluble chelating polymers that are designed to selectively bind with metal ions in aqueous solutions. The polymers have a sufficiently large molecular weight that they can be separated and concentrated using available ultrafiltration (UF) technology. The UF range is generally considered to include molecular weights from about 3000 to several million daltons and particles sizes of about 2 to 1000 nm. Water and smaller unbound components of the solution pass freely through the UF membrane. The polymers can then be reused by changing the solution conditions to release the metal ions that are recovered in concentrated form for recycle or disposal. Some of the advantages of polymer filtration relative to technology now in use are rapid binding kinetics, high selectivity, low energy and capital costs, and a small equipment footprint. Some potential commercial applications include electroplating rinse waters, photographic processing, nuclear power plant cooling water; remediation of contaminated soils and groundwater; removal of mercury contamination; and textile, paint and dye production. The purpose of this project is to evaluate this technology to remove plutonium, americium, and other regulated metal ions from various process and waste streams found in nuclear facilities. The work involves preparation of the water-soluble chelating polymers; small-scale testing of the chelating polymer systems for the required solubility, UF properties, selectivity and binding constants; followed by an engineering assessment at a larger scale to allow comparison to competing separation technologies. This project focuses on metal-ion contaminants in waste streams at the Plutonium Facility and the Waste Treatment Facility at LANL. Potential applications at other DOE facilities are also apparent.

  14. Water-soluble chelating polymers for removal of actinides from wastewater

    International Nuclear Information System (INIS)

    Polymer filtration is a technology under development to selectively recover valuable or regulated metal ions from process or wastewaters. The technology uses water-soluble chelating polymers that are designed to selectively bind with metal ions in aqueous solutions. The polymers have a sufficiently large molecular weight that they can be separated and concentrated using available ultrafiltration (UF) technology. The UF range is generally considered to include molecular weights from about 3000 to several million daltons and particles sizes of about 2 to 1000 nm. Water and smaller unbound components of the solution pass freely through the UF membrane. The polymers can then be reused by changing the solution conditions to release the metal ions that are recovered in concentrated form for recycle or disposal. Some of the advantages of polymer filtration relative to technology now in use are rapid binding kinetics, high selectivity, low energy and capital costs, and a small equipment footprint. Some potential commercial applications include electroplating rinse waters, photographic processing, nuclear power plant cooling water; remediation of contaminated soils and groundwater; removal of mercury contamination; and textile, paint and dye production. The purpose of this project is to evaluate this technology to remove plutonium, americium, and other regulated metal ions from various process and waste streams found in nuclear facilities. The work involves preparation of the water-soluble chelating polymers; small-scale testing of the chelating polymer systems for the required solubility, UF properties, selectivity and binding constants; followed by an engineering assessment at a larger scale to allow comparison to competing separation technologies. This project focuses on metal-ion contaminants in waste streams at the Plutonium Facility and the Waste Treatment Facility at LANL. Potential applications at other DOE facilities are also apparent

  15. Decorporation of inhaled actinides by chelation therapy

    International Nuclear Information System (INIS)

    This article describes recent work in NRPB laboratories that has identified some of the factors influencing the behaviour of plutonium, americium and curium compounds in the body after inhalation, together with a number of experimental approaches that are being developed to optimise their treatment with DTPA. It is concluded that the most effective treatment has yet to be developed, but progress must depend on a better understanding of the factors governing the transport of actinides in the body. It cannot be assumed that because the inhaled material is readily translocated to blood, that treatment regimens with Ca-DTPA based solely on previous understanding of the metabolic fate of soluble actinide complexes will be successful. In fact, depending on the nature of the material involved in the accident, inhalation alone or combined with prolonged infusion of DTPA may be more effective than the periodic intravenous injections of the chelating agent alone. For poorly transportable materials such as insoluble plutonium-239 dioxide, chelation treatment remains essentially ineffective. (U.K.)

  16. Combined chelation based on glycosyl-mono- and bis-hydroxypyridinones for aluminium mobilization: solution and biodistribution studies.

    Science.gov (United States)

    Chaves, Sílvia; Dron, Paul I; Danalache, Florina A; Sacoto, Diana; Gano, Lurdes; Santos, M Amélia

    2009-11-01

    Taking into account the recognized interest of a poly-pharmacological strategy in chelation therapy, a study of aluminium combined chelation based on 3-hydroxy-4-pyridinone (3,4-HP) compounds with complementary properties, associated to different denticity, size and extrafunctionality, is presented herein. In particular, Al-chelation has been explored, using a tetradentate IDA bis-(3,4-HP) ligand, L, and two N-glycosyl mono-(3,4-HP) derivatives (A or B). Combined complexation studies with the tetradentate and the most promising bidentate ligand (A) evidenced the formation of ternary complexes with high thermodynamic stability (Al-L-A) being the predominant species at physiological pH. In vivo studies on the ability for radiotracer ((67)Ga) removal from loaded mice, as a model of aluminium accumulation in body, have shown that the simultaneous administration to (67)Ga-loaded mice of a mono- and a bis-(3,4-HP) chelator (e.g. A and L) leads to a rapid metal elimination from main organs and whole animal model. This may be rationalized by coadjuvation and eventual synergistic effects, due to complementary accessibility of the chelators to different cellular compartments. PMID:19748126

  17. F-Element ion chelation in highly basic media. Annual progress report, October 1, 1996 - July 1, 1997

    International Nuclear Information System (INIS)

    'The specific fundamental chemical objectives of this project are to: (1) study the chemical speciation of Sr and Ln ions in basic media formed in aqueous solutions with and without classical chelation agents (e.g., EDTA, polyphosphates, and organic carboxylates); (2) prepare pyridine N-oxide phosphonate and phosphonoacetate chelators of the types 1--3 and characterize their ionization properties by titrimetric techniques; (3) study the interactions of 5--7 with soluble oxide-hydroxide metallate species and higher molecular weight sols, gels and precipitates containing Sr and Ln ions, as time permits, interactions with oxide-hydroxide metallates of U, Th, Ba, Al and Fe will also be studied; (4) study the interactions of newly designed phosphonate ligands with oxide-hydroxide metallate species; (5) transfer the fundamental coordination chemistry revealed here to research groups at LANL and PNNL that will utilize the results to improve tank waste treatment protocols.'

  18. Preparation and properties of a new chelating resin containing 1-nitroso-2-naphthol as the functional group.

    Science.gov (United States)

    Ghosh, J P; Das, H R

    1981-04-01

    A macroreticular polystyrene-based chelating ion-exchanger containing 1-nitroso-2-naphthol as the functional group has been synthesized. The exchange-capacity of the resin for a number of metal ions such as copper(II), iron(III), cobalt(II), nickel(II), palladium(II) and uranium(VI) as a function of pH has been determined. The sorption and elution characteristics for palladium(II) and uranium(VI) have been thoroughly examined with a view to utilizing the resin for separation and concentration of uranium and palladium. Uranium(VI) has been separated from a mixture of ten other metal ions by sorption on the chelating resin and selective elution with 0.5M sodium carbonate. Palladium(II) has been separated from various metal ions by selective sorption on the resin in 1M hydrochloric acid medium. PMID:18962916

  19. Inapplicability of high pressure spray injection for chelate administration

    International Nuclear Information System (INIS)

    A high-pressure spray injector was tested for use in injecting chelating agents around radionuclides in wounds. It was difficult to employ because of the force required for proper injection, and it did not improve the effectiveness of the injected chelate in removing intramuscularly injected 238Pu. (U.S.)

  20. Chelation Properties of Modified Humic Acids Toward Some Trivalent Lanthanide Ions

    International Nuclear Information System (INIS)

    Three kinds of humic acids, Fluka (I), Fluka (II), and Ega-chemie (III) were modified through condensation with formaldehyde to afford polymers I, II, and III, respectively. The chelation behavior of these modified humic acids polymers towards the trivalent lanthanide metal-ions, La3+, Ce3+, Nd3+, Sm3+, and Gd3+ was studied by a batch equilibration technique at 25 deg. C as a function of contact time, pH, counter ion and counter ion concentration. The highest metal-ion uptake of the three polymers was achieved at pH 7.0 and by using perchlorate as a counter ion. Results of the study have revealed that polymer II has the highest metal-ion uptake capacity, and that the metal-ion uptake falls in the order: Gd3+ > Sm3+ > Nd3+ > La3+ ≅ Ce3+

  1. Protective effects of ion-imprinted chitooligosaccharides as uranium-specific chelating agents against the cytotoxicity of depleted uranium in human kidney cells

    International Nuclear Information System (INIS)

    Occupational internal contamination with depleted uranium (DU) compounds can induce radiological and chemical toxicity, and an effective and specific uranium-chelating agent for clinical use is urgently needed. The purpose of this study was to investigate whether a series of synthesized water-soluble metal-ion-imprinted chitooligosaccharides can be used as uranium-specific chelating agents, because the chitooligosaccharides have excellent heavy metal ion chelation property and the ion-imprinting technology can improve the selective recognition of template ions. DU-poisoned human renal proximal tubule epithelium cells (human kidney 2 cells, HK-2) were used to assess the detoxification of these chitooligosaccharides. The DU-chelating capacity and selectivity of the chitooligosaccharides were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Cell viability, cellular accumulation of DU, membrane damage, DNA damage, and morphological changes in the cellular ultrastructure were examined to assess the detoxification of these chitooligosaccharides. The results showed that the Cu2+-imprinted chitooligosaccharides, especially the Cu2+-imprinted glutaraldehyde-crosslinked carboxymethyl chitooligosaccharide (Cu-Glu-CMC), chelated DU effectively and specifically, and significantly reduced the loss of cell viability induced by DU and reduced cellular accumulation of DU in a dose-dependent manner, owing to their chelation of DU outside cells and their prevention of DU internalization. The ultrastructure observation clearly showed that Cu-Glu-CMC-chelated-DU precipitates, mostly outside cells, were grouped in significantly larger clusters, and they barely entered the cells by endocytosis or in any other way. Treatment with Cu-Glu-CMC also increased the activity of antioxidant enzymes, and reduced membrane damage and DNA damage induced by DU oxidant injury. Cu-Glu-CMC was more effective than the positive control drug, diethylenetriaminepentaacetic acid (DTPA), in

  2. Copper, dioxouranium(VI) and lanthanide chelates of carboxymethylthiosuccinic acid

    International Nuclear Information System (INIS)

    Carboxymethylthiosuccinic acid (CMTSA) has three dissociable - COOH groups with pK values 2.91, 3.91, 5.03. Assignment of these values to the different carboxylic groups is given. Cu(II) and UO22+ chelates with CMSTA have been studied potentiometrically at 30degC and μ = 0.1M. The effects of dielectric constant of the solvent medium (dioxane-water) and the ionic strength, on these chelates have been examined. The lanthanides form 1:1 and 1:2 chelates with CMTSA. The plots of log K1 and (log K1 + log K2) versus e2/2r show a break at gadolinium. The thermodynamic parameters for these chelates have been determined. Smaller values of DELTAH show the predominance of the entropy effect in the formation of these chelates. (author)

  3. Fixation kinetics of chelated and non-chelated zinc in semi-arid alkaline soils: application to zinc management

    Science.gov (United States)

    Udeigwe, Theophilus K.; Eichmann, Madeleine; Menkiti, Matthew C.

    2016-07-01

    This study was designed to examine the fixation pattern and kinetics of zinc (Zn) in chelated (ethylenediaminetetraacetic acid, EDTA) and non-chelated mixed micronutrient systems of semi-arid alkaline soils from the Southern High Plains, USA. Soils were characterized for a suite of chemical and physical properties and data obtained from extraction experiments fitted to various kinetic models. About 30 % more plant-available Zn was fixed in the non-chelated system within the first 14 days with only about 18 % difference observed between the two systems by day 90, suggesting that the effectiveness of the chelated compounds tended to decrease over time. The strengths of the relationships of change in available Zn with respect to other micronutrients (copper, iron, and manganese) were higher and more significant in the non-chelated system (average R2 of 0.83), compared to the chelated (average R2 of 0.42). Fixation of plant-available Zn was best described by the power-function model (R2 = 0.94, SE = 0.076) in the non-chelated system, and was poorly described by all the models examined in the chelated system. Reaction rate constants and relationships generated from this study can serve as important tools for micronutrient management and for future micronutrient modeling studies on these soils and other semi-arid regions of the world.

  4. The iron chelator desferrioxamine attenuates postischemic ventricular dysfunction

    International Nuclear Information System (INIS)

    Recent evidence suggests that postischemic myocardial dysfunction (stunning) may be mediated by oxygen free radicals, but the mechanism by which they produce myocellular damage remains unknown. Since iron catalyzes formation of hydroxyl radicals (HO·) as well as HO·-initiated lipid peroxidation, the authors explored the potential role of this metal in the pathogenesis of myocardial stunning. Open-chest dogs undergoing a 15-min occlusion of the left anterior descending coronary artery (LAD) followed by 4 h of reperfusion (REP) received the iron chelator desferrioxamine intravenously or normal saline. Regional myocardial function was assessed by measuring systolic wall thickening with an epicardial Doppler probe. The two groups exhibited comparable systolic thickening under base-line conditions and similar degrees of dyskinesis during ischemia. After REP, however, recovery of contractile function as considerably greater in desferrioxamine-treated compared with control dogs. These differences could not be ascribed to hemodynamic factors. The results suggest that iron-catalyzed reactions (possibly HO· generation) play a significant role in myocardial stunning after a brief episode of reversible regional ischemia

  5. Multidentate dipyridyl derivatives as chelates for rhenium (V)

    International Nuclear Information System (INIS)

    Rhenium (V) complexes with the following multidentate dipyridyl ligands were prepared: 2,2'-dipyridylamine (DPA), 1,2-bis(2-pyridyl)ethylene (DPE) and di-(2-picolyl)amine (HDIPA). Reactions of a twofold molar excess of the potentially NN donor ligand DPA with trans-[ReO (OEt)Cl2(PPh3)2] in ethanol led to isolation of a monomer [ReOCl2(OEt)(DPA)] (1). Treatments of trans-[ReOCl3(PPh3)2] with a tenfold molar excess of DPA in ethanol at reflux yielded [ReO2(dpa)2]Cl (2), but with a twofold molar excess a dimer (μ-O)[{ReOCl2(dpa)}2] (3a) was isolated. The latter reaction with (n-Bu4N)[ReOCl4] as starting material in ethanol at room temperature led to a dark green product, also with the formulation (μ-O)[{ReOCl2(dpa)}2] (3b). Reacting equimolar quantities of (n-Bu4N)[ReOCl4] and HDIPA in acetone led to [ReOCl(OH2)(DIPA)Cl (4) in which HDIPA acted as a monoanionic terdentate chelate. The reaction of trans-[ReOCl3(PPh3)2] with DPE, in which DPE undergoes a metal-promoted nucleophilic attack by a water molecule, produces a complex with a general formula [ReO(DPE.OH)Cl2] (5). (author)

  6. Modelling studies in aqueous solution of lanthanide (III) chelates designed for nuclear magnetic resonance biomedical applications

    Science.gov (United States)

    Henriques, E. S.; Geraldes, C. F. G. C.; Ramos, M. J.

    Molecular dynamics simulations and complementary modelling studies have been carried out for the [Gd(DOTA)·(H2O)]- and [Tm(DOTP)]5- chelates in aqueous media, to provide a better understanding of several structural and dynamical properties of these versatile nuclear magnetic resonance (NMR) probes, including coordination shells and corresponding water exchange mechanisms, and interactions of these complexes with alkali metal ions. This knowledge is of key importance in the areas of 1H relaxation and shift reagents for NMR applications in medical diagnosis. A new refinement of our own previously developed set of parameters for these Ln(III) chelates has been used, and is reported here. Calculations of water mean residence times suggest a reassessment of the characterization of the chelates' second coordination shell, one where the simple spherical distribution model is discarded in favour of a more detailed approach. Na+ probe interaction maps are in good agreement with the available site location predictions derived from 23Na NMR shifts.

  7. Synthesis of chelating agents for actinium 225 complexation and its application in radioimmunotherapy

    International Nuclear Information System (INIS)

    Immunotherapy with radiolabeled antibodies should allow fairly specific targeting of certain cancers. However, iodine 131 may not be the best isotope for tumor therapy because of its limited specific activity, low beta-energy, relatively long half life and strong gamma emission. Another approach to improve therapeutic efficacy is the use of replacement isotopes with better physical properties. Chelator that can hold radio-metals with high stability under physiological conditions are essential to avoid excessive damage to non-target cells; Moreover, the development of new bifunctional chelating agents is essential for this purpose. Accordingly, our efforts have been directed, for several years, to the synthesis of original chelating agents likely to form stable complexes in vivo with the numerous potential candidates for such applications. Therefore, we have developed a new simple and efficient synthesis pathway of 2-(4-iso-thio-cyanate-benzyl)-1,4,7,10,13,16- hexa-aza-cyclo-hexadecane- 1,4,7,10,13,16-hexa-acetic acid, though functionalized on the cycle by a termination allowed coupling to an antibody or any other biological substance such as a hapten. (author)

  8. Investigation of metal–flavonoid chelates and the determination of flavonoids via metal–flavonoid complexing reactions

    Directory of Open Access Journals (Sweden)

    DUSAN MALESEV

    2007-10-01

    Full Text Available Flavonoids constitute a large group of polyphenolic phytochemicals with antioxidant properties which are overwhelmingly exerted through direct free radical scavenging. Flavonoids also exhibit antioxidant properties through chelating with transition metals, primarily Fe(II, Fe(III and Cu(II, which participate in reactions generating free radicals. Metal–flavonoid chelates are considerably more potent free radical scavengers than the parent flavonoids and play a prominent role in protecting from oxidative stress. To unravel the origin of their potent biological action extensive physico–chemical studies were undertaken to reveal the chemical structure, chelation sites, assess the impact of the metal/ligand ratio on the structure of the complexes and the capacity of flavonoids to bind metal ions. In spite of such extensive efforts, data on the composition, structure and complex-formation properties are incomplete and sometimes even contradictory. The aim of this paper is to give a personal account on the development of the field through a retrospective evaluation of our own research which covers approximately 40 complexes of flavonoids from different flavonoids subclasses (rutin, quercetin, 3-hydroxyflavone, morin and hesperidin with several metal ions or groups and suggest directions for future research. Special emphasis will be given to the site of the central ion, the composition of the complexes, the role of pH in complex formation, the stability of metal–flavonoid complexes and their potential application for analytical purposes.

  9. Effect of pH on the release of radionuclides and chelating agents from cement-solidified decontamination ion-exchange resins collected from operating nuclear power stations

    International Nuclear Information System (INIS)

    Data are presented on the physical stability and leachability of radionuclides and chelating agents from cement-solidified decontamination ion-exchange resin wastes collected from two operating commercial light water reactors. Small-scale waste--form specimens collected during solidifications performed at the Brunswick Steam Electric Plant Unit 1 and at the James A. FitzPatrick Nuclear Power Station were leach-tested and subjected to compressive strength testing in accordance with the Nuclear Regulatory Commission's ''Technical Position on Waste Form'' (Revision 1). Samples of untreated resin waste collected from each solidification vessel before the solidification process were analyzed for concentrations of radionuclides, selected transition metals, and chelating agents to determine the quantities of these chemicals in the waste-form specimens. The chelating agents included oxalic, citric, and picolinic acids. In order to determine the effect of leachant chemical composition and pH on the stability and leachability of the waste forms, waste-form specimens were leached in various leachants. Results of this study indicate that differences in pH do not affect releases from cement-solidified decontamination ion-exchange resin waste forms, but that differences in leachant chemistry and the presence of chelating agents may affect the releases of radionuclides and chelating agents. Also, this study indicates that the cumulative releases of radionuclides and chelating agents are similar for waste- form specimens that decomposed and those that retained their general physical form. 36 refs., 60 figs., 28 tabs

  10. Identifying Chelators for Metalloprotein Inhibitors Using a Fragment-Based Approach

    OpenAIRE

    Jacobsen, Jennifer A.; Fullagar, Jessica; Miller, Melissa T.; Cohen, Seth M.

    2010-01-01

    Fragment-based lead design (FBLD) has been used to identify new metal-binding groups for metalloenzyme inhibitors. When screened at 1 mM, a chelator fragment library (CFL-1.1) of 96 compounds produced hit rates ranging from 29–43% for five matrix metalloproteases (MMPs), 24% for anthrax lethal factor (LF), 49% for 5-lipoxygenase (5-LO), and 60% for tyrosinase (TY). The ligand efficiencies (LE) of the fragment hits are excellent, in the range of 0.4–0.8 kcal/mol. The MMP enzymes all generally ...

  11. Research progress on supercritical fluid chelating extraction of lanthanides and actinides

    International Nuclear Information System (INIS)

    Supercritical fluid chelating extraction (SFCE) is a new type of separation technology for extracting metallic elements. When SFCE is used in both the spent fuel reprocessing and the treatment of nuclear wastes, the generation of second wastes can be minimized. Both the properties of supercritical fluid and the theory of SFCE were introduced, and factors affecting SFCE were discussed in the paper. The research progress on SFCE of lanthanides and actinides and applications in the process study of spent fuel reprocessing were reviewed too. (authors)

  12. Bis-ligated Ti and Zr complexes of chelating N-heterocyclic carbenes

    KAUST Repository

    El-Batta, Amer

    2011-07-01

    In this communication we report the synthesis of novel titanium and zirconium complexes ligated by bidentate "salicylaldimine-like" N-heterocyclic carbenes (NHC). Double addition of the NHC chelate to either TiCl4(thf)2 or ZrCl4 forms bis-ligated organometallic fragments with a distorted octahedral geometry. These complexes are rare examples of group IV transition-metal NHC adducts. Preliminary catalytic tests demonstrate that in the presence of methylaluminoxane (MAO) these complexes are useful initiators for the polymerization of ethylene and the copolymerization of ethylene with norbornene and 1-octene. © 2011 Elsevier B.V. All rights reserved.

  13. A study on the photocatalytic reaction of the metals and organics

    Energy Technology Data Exchange (ETDEWEB)

    Nah, Jung Won; Cho, Yung Hyun; Sung, Ki Woong; Kim, Yong Ik; Hong, Kwang Bum; Kang, Heui Suk; Koo, Je Hyoo; Kim, Kwang Lak; Paek, Seung Woo; Lee, Han Soo; Chung, Heung Suk [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Chung, Yong Won [In Hah Univ., Inchun (Korea, Republic of)

    1994-12-01

    Lead metal ion was selected as the model one in the experiment for photo catalytic reaction containing EDTA. Disappearance rate of lead ion in solution was analyzed with control variables of initial pH value, concentration of chelating agent, and concentration ratio of metal ion and chelating agent. 31 figs, 6 tabs, 67 refs. (Author).

  14. Screening wheat genotypes in response to ordinary chelate and nano-iron chelate fertilizers in nutrient solution

    OpenAIRE

    S. Omidi Nargesi; Zahedi, M; H.R. Eshghizadeh; A.H. Khoshgoftarmanesh

    2015-01-01

    Recently, attentions have been taken on the investigations regarding the use of nano-sized compounds in different fields including agricultural sector. Due to the importance of evaluating the fate and operation of nano-particles in plant systems, in this survey, responses of 13 wheat genotypes to the effect of nano-iron chelate fertilizer in the Hoagland solution under the conditions of ordinary iron chelate and nano-iron chelate, with concentration of 22.5 mg/L, was studied. This experiment ...

  15. Mixed-chelate therapy of intratracheally deposited cadmium oxide

    International Nuclear Information System (INIS)

    Mixed-chelate treatment with EDTA and salicylic acid was no more effective in accelerating the removal of intratracheally instilled 109CdO, or in protecting against CdO-induced mortality, than was EDTA given alone

  16. Chelated Ruthenium Catalysts for Z-Selective Olefin Metathesis

    OpenAIRE

    Endo, Koji; Grubbs, Robert H.

    2011-01-01

    We report the development of ruthenium-based metathesis catalysts with chelating N-heterocyclic carbene (NHC) ligands which catalyze highly Z-selective olefin metathesis. A very simple and convenient synthetic procedure of such a catalyst has been developed. An intramolecular C-H bond activation of the NHC ligand, which is promoted by anion ligand substitution, forms the appropriate chelate for stereo- controlled olefin metathesis.

  17. Μethods of iron chelation therapy: a bibliographic review

    OpenAIRE

    Maria Agapiou; Elpida Georgiadi

    2012-01-01

    "Iron Chelation Therapy" is a term used to describe the procedure of removing excess iron from the body, which is applied after a total of approximately 20 blood transfusions or when serum ferritin levels rise above 1000 ng/ml. Aim: The purpose of the present paper is a retrospective search in bibliography, concerning the methods of iron chelation treatment for patients with hemochromatosis owing to their undergoing multiple blood transfusions. Method: The methology followed, included the sea...

  18. EDTA chelation therapy for cardiovascular disease: a systematic review

    OpenAIRE

    Wu Ping; Seely Dugald MR; Mills Edward J

    2005-01-01

    Abstract Background Numerous practitioners of both conventional and complementary and alternative medicine throughout North America and Europe claim that chelation therapy with EDTA is an effective means to both control and treat cardiovascular disease. These claims are controversial, and several randomized controlled trials have been completed dealing with this topic. To address this issue we conducted a systematic review to evaluate the best available evidence for the use of EDTA chelation ...

  19. Iron chelators ICL670 and 311 inhibit HIV-1 transcription

    International Nuclear Information System (INIS)

    HIV-1 replication is induced by an excess of iron and iron chelation by desferrioxamine (DFO) inhibits viral replication by reducing proliferation of infected cells. Treatment of cells with DFO and 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311) inhibit expression of proteins that regulate cell-cycle progression, including cycle-dependent kinase 2 (CDK2). Our recent studies showed that CDK2 participates in HIV-1 transcription and viral replication suggesting that inhibition of CDK2 by iron chelators might also affect HIV-1 transcription. Here we evaluated the effect of a clinically approved orally effective iron chelator, 4-[3,5-bis-(hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid (ICL670) and 311 on HIV-1 transcription. Both ICL670 and 311 inhibited Tat-induced HIV-1 transcription in CEM-T cells, 293T and HeLa cells. Neither ICL670 nor 311 induced cytotoxicity at concentrations that inhibited HIV-1 transcription. The chelators decreased cellular activity of CDK2 and reduced HIV-1 Tat phosphorylation by CDK2. Neither ICL670A or 311 decreased CDK9 protein level but significantly reduced association of CDK9 with cyclin T1 and reduced phosphorylation of Ser-2 residues of RNA polymerase II C-terminal domain. In conclusion, our findings add to the evidence that iron chelators can inhibit HIV-1 transcription by deregulating CDK2 and CDK9. Further consideration should be given to the development of iron chelators for future anti-retroviral therapeutics

  20. Determination of trace elements in natural water samples by sir-segmented flow-injection/ICP-MS after preconcentration with a chitosan-based chelating resin

    International Nuclear Information System (INIS)

    Ultratrace elements in natural water samples were determined simultaneously by air-segmented flow-injection/inductively coupled plasma-mass spectrometry (SFI/ICP-MS). A small volume of the sample solutions (80 μl) was introduced into a nebulizer by an air-segmented flow-injection (SFI) system, and a maximum of fifteen elements were measured during each run. A chitosan-based chelating resin containing functional groups of iminodiacetate was used to separate and enrich analyte metal ions. A 50-fold preconcentration using 50 ml of sample solutions was achieved by the proposed method, where 1 ml of 0.1 M nitric acid was added to residues after drying the chelating column effluent. At pH 6, several heavy metals (Fe, Ni, Co, Cu, Zn, Ag, Cd, Pb and U) and rare earth elements (REEs) were quantitatively retained on the chelating resin column, whereas alkali and alkaline earth metals were eluted from the column by rinsing with 5 ml of a 0.2 M ammonium acetate solution. Metals adsorbed on the chelating resin column were recovered by elution with 10 ml of 1 M nitric acid. The proposed method was applied to the determination of trace elements in several natural water samples, such as river water and mineral drinking water. (author)

  1. Determination of trace elements in natural water samples by sir-segmented flow-injection/ICP-MS after preconcentration with a chitosan-based chelating resin

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.H.; Oshima, Mitsuko; Motomizu, Shoji [Department of Chemistry, Faculty of Science, Okayama University, Okayama (Japan)

    2000-07-01

    Ultratrace elements in natural water samples were determined simultaneously by air-segmented flow-injection/inductively coupled plasma-mass spectrometry (SFI/ICP-MS). A small volume of the sample solutions (80 {mu}l) was introduced into a nebulizer by an air-segmented flow-injection (SFI) system, and a maximum of fifteen elements were measured during each run. A chitosan-based chelating resin containing functional groups of iminodiacetate was used to separate and enrich analyte metal ions. A 50-fold preconcentration using 50 ml of sample solutions was achieved by the proposed method, where 1 ml of 0.1 M nitric acid was added to residues after drying the chelating column effluent. At pH 6, several heavy metals (Fe, Ni, Co, Cu, Zn, Ag, Cd, Pb and U) and rare earth elements (REEs) were quantitatively retained on the chelating resin column, whereas alkali and alkaline earth metals were eluted from the column by rinsing with 5 ml of a 0.2 M ammonium acetate solution. Metals adsorbed on the chelating resin column were recovered by elution with 10 ml of 1 M nitric acid. The proposed method was applied to the determination of trace elements in several natural water samples, such as river water and mineral drinking water. (author)

  2. Improving the efficiency of phytoremediation using electrically charged plant and chelating agents.

    Science.gov (United States)

    Tahmasbian, Iman; Safari Sinegani, Ali Akbar

    2016-02-01

    The low efficiency of phytoremediation is a considerable problem that limits the application of this environmentally friendly method on heavy metal-polluted soils. The combination of chelate-assisted phytoextraction and electrokinetic remediation could offer new opportunities to improve the effectiveness of phytoextraction. The current experiment aims to investigate the effects of electrical fields and chelating agents on phytoremediation efficiency. In a pot experiment using mine soil, poultry manure extract (PME), cow manure extract (CME), and ethylenediaminetetraacetic acid (EDTA) were applied to soil as chelating agents (2 g kg(-1)) at the beginning of the flowering stage. A week later, Helianthus annuus (sunflower) was negatively charged by inserting a stainless steel needle with 10 and 30 V DC electricity in the lowest part of the stems for 1 h each day for a 14-day period. At the end of the experiment, the shoot and root dry weight, lead (Pb) concentration in plant organs, translocation factor (TF), metal uptake index (UI), and soil available Pb (diethylene triamine pentaacetic acid (DTPA) extractable) were detected. Results indicated that the application of electrical fields had no significant impact on the shoot and root dry weights, while Pb concentration and UI increased in the 10-V EDTA treatment by 500 % compared to control. There was no significant difference between UI in 30- and 10-V EDTA treatments. Soil available Pb significantly increased in the 30-V treated soil. A positive correlation was observed between the available Pb in soil near the root and Pb concentration in shoot, its TF, and UI. In conclusion, a negatively charged plant along with the application of EDTA significantly increased the phytoremediation efficiency. PMID:26423283

  3. D-Penicillamine tripodal derivatives as efficient copper(I) chelators.

    Science.gov (United States)

    Jullien, Anne-Solène; Gateau, Christelle; Lebrun, Colette; Kieffer, Isabelle; Testemale, Denis; Delangle, Pascale

    2014-05-19

    New tripodal metal-chelating agents derived from nitrilotriacetic acid (NTA) and extended by three unnatural amino acids D-penicillamine (D-Pen) are presented. D-Pen is actually the drug most extensively used to treat copper (Cu) overload in Wilson's disease and as such is a very attractive building block for the design of chelating agents. D-Pen is also a bulkier analogue of cysteine, with the β-methylene hydrogen atoms replaced by larger methyl groups. The hindrance of the gem-dimethyl group close to the thiol functions is demonstrated to influence the speciation and stability of the metal complexes. The ligands L(4) (ester) and L(5) (amide) were obtained from NTA and commercial D-Pen synthons in four and five steps with overall yields of 14 and 24%, respectively. Their ability to bind Cu(I), thanks to their three thiolate functions, has been investigated using both spectroscopic and analytical methods. UV, CD, and NMR spectroscopy and mass spectrometry evidence the formation of two Cu(I) complexes with L(5): the mononuclear complex CuL(5) and one cluster (Cu2L(5))2. In contrast, the bulkier ethyl ester derivative L(4) cannot accommodate the mononuclear complex in solution and thus forms exclusively the cluster (Cu2L(4))2. Cu K-edge X-ray absorption spectroscopy (XAS and EXAFS) confirms that Cu(I) is bound in trigonal-planar sulfur-only environments in all of these complexes with Cu- - -S distances ranging from 2.22 to 2.23 Å. Such C3-symmetric CuS3 cores are coordination modes frequently adopted in Cu(I) proteins such as metallothioneins. These two ligands bind Cu(I) tightly and selectively, which makes them promising chelators for intracellular copper detoxification in vivo. PMID:24766067

  4. FINAL REPORT. "GREEN" BIOPOLYMERS FOR IMPROVED DECONTAMINATION OF METALS FROM SURFACES: SORPTIVE CHARACTERIZATION AND COATING PROPERTIES

    Science.gov (United States)

    The proposed research aimed to develop a fundamental understanding of important biological and physical chemical parameters for effective decontamination of metal surfaces using environmentally benign aqueous-based biopolymer solutions. Understanding how heavy metal-chelating bio...

  5. "GREEN" BIOPOLYMERS FOR IMPROVED DECONTAMINATION OF METALS FROM SURFACES: SORPTIVE CHARACTERIZATION AND COATING PROPERTIES

    Science.gov (United States)

    The proposed research aims to develop a fundamental understanding of important biological and physical chemical parameters for effective decontamination of metal surfaces using environmentally benign aqueous-based biopolymer solutions. Understanding how heavy metal- chelating bio...

  6. Development of chelate tagging method of protein at low temperature

    International Nuclear Information System (INIS)

    This study aimed at development of a protein labelling method at a low temperature, available for functional proteins, such as antibodies and enzymes mostly unstable at high temperatures. A solution of anti-mouse IgG antibody added with EDTA was incubated with 51CrCl3 at 4degC for 24 hours. After stopping the reaction with 100-fold amount of EDTA-2Na, the solution was fractionated into antibody fraction and metal fraction by HPLC. After incubation, non-specific Cr adsorption on the antibody in no relation to the chelate reagent was chased with 10-fold amount of CrCl3. To remove free Cr, the sample solution was incubated with 10 to 50-fold ICB-EDTA solution containing N,N-dimethyl-formamide. Then, the amount of Cr-labelling on the antibody was determined. In Western-blotting, chick actin was applied onto SDS-polyacrylamide gel electrophoresis. One part of the lane was stained with brilliant-blue and the other was transferred on nitrocellulose membrane by semi-dry method and stained with panceau-S. Anti-actin monoclonal antibody and anti-mouse IgG antibody were used as the first antibody and the second one, respectively. When incubated with ICB-EDTA for 3 days, labelling reached the maximum level. Although labelling of the second antibody was performed with maleimido-C3-benzyl EDTA and 45Ca as a substitute for 51Cr, the rate of labelling was lower than the rate for a combination of ICB-EDTA and 51Cr. Autoradiography of the anti-mouse IgG preparation after SDS-acrylamide gel electrophoresis revealed that radioactivity was detected on the site of H-chain but not L-chain. This indicates that 51Cr labelling of protein is stable even under the conditions of SDS denaturation. (M.N.)

  7. Assessing the Impact of EDTA Chelating Effect on some Macro- and Microminerals in Prussian Carp (Carassius Gibelio Tissues

    Directory of Open Access Journals (Sweden)

    Marioara Nicula

    2011-10-01

    Full Text Available Chelators are used in chemical analysis, in medical aplications, as water softeners, as decontamination agents on radioactive surfaces and they are ingredients in many commercial products such as shampoos and food preservatives. Such a synthetic chelator is EDTA (ethylenediaminetetraacetic acid. It is considered one of the tools that promises to control the heavy metal pollution in aquaculture. EDTA attaches itself to heavy metals and carries the metals from the fish body. EDTA can also slow free-radical activity produced by heavy metals in the body. Because its ability to sequester metal ions, we tried to estimate the potential risks of a chronic exposure to EDTA on tissue mobilization of some metals which have an essential role in realization of different cell functions in Prussian carp specimens. Ca, Mg, Fe, Zn. Mn and Cu, were the mineral elements we have targeted in this study. It was found that these minerals have a trend of their tissues distribution and concentration in the body of the control specimens (higher or lower related to other similar works and EDTA presence in water led to a significant decreasing of their level in all tissues analyzed in a dose-dependent manner.

  8. Direct current-induced electrogenerated chemiluminescence of hydrated and chelated Tb(III) at aluminum cathodes

    International Nuclear Information System (INIS)

    Cathodic DC polarization of oxide-covered aluminum produces electrogenerated chemiluminescence from hydrated and chelated Tb(III) ions in aqueous electrolyte solutions. At the moment of cathodic voltage onset, a strong cathodic flash is observed, which is attributed to a tunnel emission of hot electrons into the aqueous electrolyte solution and the successive chemical reactions with the luminophores. However, within a few milliseconds the insulating oxide film is damaged and finally dissolved due to (i) indiffusion of protons or alkali metal ions into the thin oxide film, (ii) subsequent hydrogen evolution at the aluminum/oxide interface and (iii) alkalization of the electrode surface induced by hydrogen evolution reaction. When the alkalization of the electrode surface has proceeded sufficiently, chemiluminescence is generated with increasing intensity. Aluminum metal, short-lived Al(II), Al(I) or atomic hydrogen and its conjugated base form, hydrated electron, can act as highly reducing species in addition to the less energetic heterogeneously transferred electrons from the aluminum electrode. Tb(III) added as a hydrated ion in the solution probably luminesces in the form of Tb(OH)3 or Tb(OH)4- by direct redox reactions of the central ion whereas multidentate aromatic ligand chelated Tb(III) probably luminesces by ligand sensitized chemiluminescence mechanism in which ligand is first excited by one-electron redox reactions, which is followed by intramolecular energy transfer to the central ion which finally emits light

  9. Chemical, physical, and sensory characteristics of mozzarella cheese fortified using protein-chelated iron or ferric chloride.

    Science.gov (United States)

    Rice, W H; McMahon, D J

    1998-02-01

    Mozzarella cheese containing 25 and 50 mg of iron/kg of cheese was manufactured from milk that had been fortified with casein-chelated iron, whey protein-chelated iron, or FeCl3. Chemical, physical, and sensory characteristics were compared with those of a control cheese. Physical properties were assessed by testing melting, apparent viscosity, and browning of heated cheese. Cheeses were evaluated by trained panelists for the presence of metallic flavors, oxidized flavors, and other undesirable flavors. Addition of 25 mg iron/kg of cheese had no effects on the physical properties of Mozzarella cheese. Apparent viscosity of cheese fortified with 50 mg of iron/kg of cheese tended to be slightly higher than the control cheese, although this difference was not statistically significant at all storage times. Cook color was not affected by iron fortification. No increase in chemical oxidation (measured using thiobarbituric acid assay) was observed between the control and iron-fortified cheeses. Slight but statistically significant increases in metallic flavors, oxidized flavors, and off-flavors in the iron-fortified cheese were observed by the trained sensory panel, but the flavor defects were of very low intensity. For metallic flavors, oxidized flavors, and off-flavors, the control cheese scored 1.5, 1.5, and 1.3, respectively; the iron-fortified cheese scored 2.1, 2.0, and 1.6 based on a nine-point scale (where 1 = not perceptible to 3 = slightly perceptible). Sensory scores for iron-fortified cheese made using casein-chelated iron or whey protein-chelated iron was not significantly different from those of cheese made using ferric chloride. When used on pizza, consumer panels rated the iron-fortified cheeses as comparable with the control cheese. PMID:9532487

  10. Activation of the CXCR3 chemokine receptor through anchoring of a small molecule chelator ligand between TM-III, -IV, and -VI

    DEFF Research Database (Denmark)

    Rosenkilde, Mette M; Andersen, Michael B; Nygaard, Rie;

    2006-01-01

    Seven transmembrane segment (7TM) receptors are activated through a common, still rather unclear molecular mechanism by a variety of chemical messengers ranging from monoamines to large proteins. By introducing a His residue at position III:05 in the CXCR3 receptor a metal ion site was built...... between the extracellular ends of transmembrane (TM) III and TM-IV to anchor aromatic chelators at a location corresponding to the presumed binding pocket for adrenergic receptor agonists. In this construct, free metal ions had no agonistic effect in accordance with the optimal geometry of the metal ion...... modeling and molecular simulations combined with mutational analysis indicated that the metal ion site-anchored chelators act as agonists by establishing an aromatic-aromatic, second-site interaction with TyrVI:16 on the inner face of TM-VI. It is noteworthy that this interaction required that the...

  11. Determination of molybdenum, chromium and vanadium by ion-pair high-pressure liquid chromatography based on precolumn chelation with 4-(2-pyridylazo)resorcinol

    International Nuclear Information System (INIS)

    A reversed-phase ion-pair liquid chromatography-spectrophotometric detection system for the separation and simultaneous determination of molybdenum, chromium and vanadium is described. The chelates of the metal ions with 4-(2-pyridylazo)resorcinol are separated on a Zorbax CN column with 1 x 10-3M tetrabutylammonium iodide and 0.01M KH2P04-Na2HP04 buffer (pH 7.50) in 30:70 v/v methanol-water mixture as the mobile phase, at a flow rate of 1.0 ml/min. The chelates are detected spectrophotometrically at 540 nm. (author)

  12. Synergistic and antagonistic effects in systems containing electrolytes and nonionic surfactant micelles on the photometric and analytical characteristics of chrome azurol S chelates

    International Nuclear Information System (INIS)

    The effects of strong electrolytes and surfactant micelles on the complexation of Chrome Azurol S with Be, Cu, Al, Sc, and Fe(3) ions were examined by spectrophotometry. Simultaneous addition of electrolytes and surfactant micelles caused a synergistic effect exhibited in a dramatic increase in the absorption intensity and the concentration of chelates with a maximum number of coordination ligands in the solution. An increase in the molar absorption coefficients of chelates, an improvement of the sensitivity of determination, and a decrease in the detection limits of metals by a factor of 2-10 resulted from this effect

  13. Cage-like bifunctional chelators, copper-64 radiopharmaceuticals and PET imaging using the same

    Energy Technology Data Exchange (ETDEWEB)

    Conti, Peter S.; Cai, Hancheng; Li, Zibo; Liu, Shuanglong

    2016-08-02

    Disclosed is a class of versatile Sarcophagine based bifunctional chelators (BFCs) containing a hexa-aza cage for labeling with metals having either imaging, therapeutic or contrast applications radiolabeling and one or more linkers (A) and (B). The compounds have the general formula ##STR00001## where A is a functional group selected from group consisting of an amine, a carboxylic acid, an ester, a carbonyl, a thiol, an azide and an alkene, and B is a functional group selected from the group consisting of hydrogen, an amine, a carboxylic acid, and ester, a carbonyl, a thiol, an azide and an alkene. Also disclosed are conjugate of the BFC and a targeting moiety, which may be a peptide or antibody. Also disclosed are metal complexes of the BFC/targeting moiety conjugates that are useful as radiopharmaceuticals, imaging agents or contrast agents.

  14. Field-Portable Immunoassay Instruments and Reagents to Measure Chelators and Mobile Forms of Uranium

    International Nuclear Information System (INIS)

    The goals for the 3-year project period are (1) to test and validate the present uranium sensor and develop protocols for its use at the NABIR Field Research Center; (2) to develop new reagents that will provide superior performance for the present hand-held immunosensor; and (3) to develop new antibodies that will permit this sensor to also measure other environmental contaminants (chromium, mercury, and/or DTPA). Sensor design modifications are underway via international collaborations. New reagents that will provide superior performance for the present hand-held immunosensor are being prepared and tested. New methods have been developed, to produce recombinant forms of metal-specific monoclonal antibodies for use with the sensor. Site-directed mutagenesis experiments are underway to determine the mechanisms of binding. Immunization experiments with sheep and rabbits to develop new recombinant forms of antibodies to metal-chelate complexes (chromium, mercury, and/or DTPA) have been initiated

  15. Syntheses of chelating tetrazole-containing ligands and studies of their palladium (II) and ruthenium (II) complexes

    International Nuclear Information System (INIS)

    Eleven chelating tetrazole-containing ligands have been synthesized, and their complexes with palladium (II) and ruthenium (II) prepared. Proton n.m.r. spectroscopy, electronic absorption spectroscopy and cyclic voltametry have been used to study the nature of the metal-ligand interactions in these complexes. The negatively charged tetrazolate group is shown to be a strong electron donor with very different properties to those of the protonated or alkylated tetrazole group. This leads to pH control of the properties of transition metal complexes containing such ligands. 13 refs., 2 tabs., 3 figs.,ill

  16. Syntheses of chelating tetrazole-containing ligands and studies of their palladium (II) and ruthenium (II) complexes

    Energy Technology Data Exchange (ETDEWEB)

    Downard, A.J.; Steel, P.J.; Steenwijk, J. [Canterbury Univ., Christchurch (New Zealand). Dept. of Chemistry

    1995-12-31

    Eleven chelating tetrazole-containing ligands have been synthesized, and their complexes with palladium (II) and ruthenium (II) prepared. Proton n.m.r. spectroscopy, electronic absorption spectroscopy and cyclic voltametry have been used to study the nature of the metal-ligand interactions in these complexes. The negatively charged tetrazolate group is shown to be a strong electron donor with very different properties to those of the protonated or alkylated tetrazole group. This leads to pH control of the properties of transition metal complexes containing such ligands. 13 refs., 2 tabs., 3 figs.,ill.

  17. Sequestration of chelated copper by structural Fe(II): Reductive decomplexation and transformation of Cu(II)-EDTA.

    Science.gov (United States)

    He, Hongping; Wu, Deli; Zhao, Linghui; Luo, Cong; Dai, Chaomeng; Zhang, Yalei

    2016-05-15

    Chelated coppers, such as Cu(II)-EDTA, are characteristically refractory and difficult to break down because of their high stability and solubility. Cu(II)-EDTA sequestration by structural Fe(II) (Fe(II)) was investigated intensively in this study. Up to 101.21mgCu(II)/gFe(II) was obtained by Fe(II) in chelated copper sequestration under near neutral pH condition (pH 7.70). The mechanism of Cu(II)-EDTA sequestration by Fe(II) was concluded as follows: 3Cu(II)-EDTA+7Fe(II)+9H2O → Cu(0)↓+ Cu2O↓(the major product)+2Fe2O3·H2O↓+3Fe(II)-EDTA +14H(+) Novel results strongly indicate that Cu(II) reductive transformation induced by surface Fe(II) was mainly responsible for chelated copper sequestration. Cu(0) generation was initially facilitated, and subsequent reduction of Cu(II) into Cu(I) was closely combined with the gradual increase of ORP (Oxidation-Reduction Potential). Cu-containing products were inherently stable, but Cu2O would be reoxidized to Cu(II) with extra-aeration, resulting in the release of copper, which was beneficial to Cu reclamation. Concentration diminution of Cu(II)-EDTA within the electric double layer and competitive adsorption were responsible for the negative effects of Ca(2+), Mg(2+). By generating vivianite, PO4(3-) was found to decrease surface Fe(II) content. This study is among the first ones to identify the indispensible role of reductive decomplexation in chelated copper sequestration. Given the high feasibility and reactivity, Fe(II) may provide a potential alternative in chelated metals pollution controlling. PMID:26878707

  18. Investigation of molecular mechanisms of action of chelating drugs on protein-lipid model membranes by X-ray fluorescence

    International Nuclear Information System (INIS)

    Protein-lipid films based on the enzyme alkaline phosphatase were subjected to the action of chelating drugs, which are used for accelerating the removal of heavy metals from the human body, and the elemental composition of the resulting films was investigated. Total-reflection X-ray fluorescence measurements were performed at the Berlin Electron Storage Ring Company for Synchrotron Radiation (BESSY) in Germany. A comparative estimation of the protective effect of four drugs (EDTA, succimer, xydiphone, and mediphon) on membrane-bound enzymes damaged by lead ions was made. The changes in the elemental composition of the protein-lipid films caused by high doses of chelating drugs were investigated. It was shown that state-of-the-art X-ray techniques can, in principle, be used to develop new methods for the in vitro evaluation of the efficiency of drugs, providing differential data on their actions.

  19. From chelating precursors to La0.05Sr0.95CoO3-y oxide

    International Nuclear Information System (INIS)

    Several La0.05Sr0.95CoO3-y (LSCO-95) powders were synthesized by means of a chelated complex-based precursor approach, which involved pyrolysis of chelating precursors and subsequent calcination of the resulting oxides. This paper focuses on the coordination effects of the precursors on the formation of the crystalline phases of the LSCO-95 oxide, showing that when the precursor is composed of EDTA-metal complexes, the perovskite-type oxide LSCO-95, an electronic-ionic mixed conducting ceramic material, can be achieved. In contrast, those LSCO-95 powders obtained initially from the pyrolysis of the precursors containing other coordination ligands possess only the undesirable hexagonal structure

  20. Encapsulation and retention of chelated-copper inside hydrophobic nanoparticles

    DEFF Research Database (Denmark)

    Hervella, Pablo; Parra, Elisa; Needham, David

    2016-01-01

    Trioleate (Triolein) with copper using the hydrophobic chelator Octaethyl porphyrin (OEP). RESEARCH PLAN AND METHODS: The research plan for this study was to (1) Formulate nanoparticles and control nanoparticle size using a modification of the solvent injection technique, named fast ethanol injection; (2......) Chelate copper into the octaethyl porphyrin; (3) Encapsulate OEP-Cu in nanoparticles: the encapsulation efficiency of copper into liquid nanoparticles (LNP), solid nanoparticles (SNP) and phospholipid liposomes (PL) was evaluated by UV-Vis and atomic absorption spectroscopy; (4) Retain the encapsulated...... minimum value for the particle diameter of ∼30nm was measured. (2) Copper was chelated by OEP in a 1:1mol ratio with an association constant of 2.57×10(5)M(-1). (3) The diameter of the nanoparticles was not significantly affected by the presence of OEP or OEP-Cu. The percentage of encapsulation of copper...

  1. Timing of early chelating therapy for acute uranium intoxication

    International Nuclear Information System (INIS)

    Rats were treated with DTPA and H-73-10 intraperitoneal injections 15 minutes to 4 days after acute uranium intoxication. The mortality and changes in body weight, kidney weight, renal histology and histochemistry were investigated. The results show that the renal damage could be diminished significantly by chelating therapy started 15 minutes and 6 hours after urnium poisoning. Single large dose injection (1 g/kg weight) of H-73-10 yielded the best result, and daily 0.5 g/kg of H-73-10 injection for 5 days is the next, both are better than single injection of DTPA (1 g/kg body weight). One day after intoxication there was still some protective effect. On the contrary, if the chelating therapy started 2-4 days after urnium poisoning it would increase the renal damage and the mortality. This is of great value to the correct selection of timing of chelating therapy for uranium intoxication

  2. Inositol hexa-phosphate: a potential chelating agent for uranium

    Energy Technology Data Exchange (ETDEWEB)

    Cebrian, D.; Tapia, A.; Real, A.; Morcillo, M.A. [Radiobiology Laboratory, Radiation Dosimetry Unit, Department of Environment, CIEMAT, Avda Complutense 22, 28040 Madrid (Spain)

    2007-07-01

    Chelation therapy is an optimal method to reduce the radionuclide-related risks. In the case of uranium incorporation, the treatment of choice is so far i.v infusion of a 1.4% sodium bicarbonate solution, but the efficacy has been proved to be not very high. In this study, we examine the efficacy of some substances: bicarbonate, citrate, diethylenetriamine pentaacetic acid (DTPA), ethidronate (EHBP) and inositol hexa-phosphate (phytic acid) to chelate uranium using a test developed by Braun et al. Different concentrations of phytic acid, an abundant component of plant seeds that is widely distributed in animal cells and tissues in substantial levels, were tested and compared to the same concentrations of sodium citrate, bicarbonate, EHBP and DTPA. The results showed a strong affinity of inositol hexa-phosphate for uranium, suggesting that it could be an effective chelating agent for uranium in vivo. (authors)

  3. Inositol hexa-phosphate: a potential chelating agent for uranium

    International Nuclear Information System (INIS)

    Chelation therapy is an optimal method to reduce the radionuclide-related risks. In the case of uranium incorporation, the treatment of choice is so far i.v infusion of a 1.4% sodium bicarbonate solution, but the efficacy has been proved to be not very high. In this study, we examine the efficacy of some substances: bicarbonate, citrate, diethylenetriamine pentaacetic acid (DTPA), ethidronate (EHBP) and inositol hexa-phosphate (phytic acid) to chelate uranium using a test developed by Braun et al. Different concentrations of phytic acid, an abundant component of plant seeds that is widely distributed in animal cells and tissues in substantial levels, were tested and compared to the same concentrations of sodium citrate, bicarbonate, EHBP and DTPA. The results showed a strong affinity of inositol hexa-phosphate for uranium, suggesting that it could be an effective chelating agent for uranium in vivo. (authors)

  4. IMPACT OF ACID WASHING AND CHELATION ON Mg(OH2-BASED HYDROGEN PEROXIDE BLEACHING OF MIXED HARDWOODS CMP AT A HIGH CONSISTENCY

    Directory of Open Access Journals (Sweden)

    Somayeh Ghasemi

    2010-09-01

    Full Text Available The removal of transition metal ions is crucial for improving the efficiency of subsequent peroxide bleaching. Acid-washing and chelation have been proposed for such a purpose. However, their influences on the Mg(OH2-based peroxide bleaching of hardwood pulps at a high consistency have not been well documented in the literature. In this work, we studied the influence of acid-washing using sulfuric acid or chelation using diethylenetriaminepentaacetic (DTPA on the Mg(OH2- or NaOH-based hydrogen peroxide bleaching efficiency, effluent properties of bleaching filtrates, and paper properties. The results showed that for Mg(OH2-based peroxide bleaching, the pulp yield and water retention value of acid-washed pulp were higher than those of the chelated pulp; the chemical oxygen demand (COD and turbidity of the bleaching filtrates for the acid-washed pulp were lower than those of the chelated pulp. The bleached acid-washed pulp had lower strength properties than bleached chelated pulp did. Additionally, at a high pulp consistency (25%, the Mg(OH2-based process had a higher bleaching efficiency and superior bleaching effluent properties, but a lower strength properties, in comparison with the NaOH-based process.

  5. Effects of some chelating agents on the uptake and distribution of 54Mn(II) in the brown trout (Salmo trutta)

    International Nuclear Information System (INIS)

    The effects of humic acids, which are natural metal-complexing compounds, and potassium ethylxanthate, sodium diethyldithiophosphate, sodium dimethyldithicarbamate, which are sulphur-containing man-made chelating agents, on the uptake and tissue distribution of 54Mn(II) were studied in brown trout (Salmo trutta). Fish were exposed for 7 days to 0.1 μg Mn(II)x.-2 as NmCl2 (l μCia 54Mnxl-1) with or without chelat agents. Examination of the partition of Mn between octanol and a Tris-HCl buffer in the presence of these compounds was also performed. Humic acids had only small effects on Mn uptake and distribution in trout, probably because of the low stability of Mn-humate complexes. Partition of Mn in the presence of potassium ethylxanthate, sodium diethyldithiophosphate, sodium dimethyldithiocarbamate, and sodium diethyldithiocarbamate between octanol and Tris-HCl buffer showed formation of lipophilic complex with the latter two compounds, but not with the former. However, these four chelating agents all decreased Mn uptake in the trout by 40-45%. These substances also changed the distribution of Mn within the fish, with a higher proportion of the metal being present in some visceral organs and a smaller proportion being localized in some non-parenchymateous tissues, such as skin, fins and bones. The mechanisms underlying these effects are not known. however, the interaction of chelating agents with the Mn, although weak, may have partially withdrawn the metal from the uptake process inthe gills. The redistribution of Mn in the fish may be due to the binding of the metal to complexing compounds which have reached the intestinal lumen. Previous studies with other metals have shown increased or unchanged metal levels in tissues of fish at exposure together with potasium ethylxanthate, sodium diethyldithiophosphate, sodium dimethyldithiocarbamate, and sodium diethyldithiocarbamate, but decreased metal levels have not been observed before. (au) (37 refs.)

  6. IR, UV-Vis, magnetic and thermal characterization of chelates of some catecholamines and 4-aminoantipyrine with Fe(III) and Cu(II)

    Science.gov (United States)

    Mohamed, Gehad G.; Zayed, M. A.; El-Dien, F. A. Nour; El-Nahas, Reham G.

    2004-07-01

    The dopamine derivatives participate in the regulation of wide variety of physiological functions in the human body and in medication life. Increase and/or decrease in the concentration of dopamine in human body reflect an indication for diseases such as Schizophrenia and/or Parkinson diseases. α-Methyldopa (α-MD) in tablets is used in medication of hypertension. The Fe(III) and Cu(II) chelates with coupled products of adrenaline hydrogen tartarate (AHT), levodopa (LD), α-MD and carbidopa (CD) with 4-aminoantipyrine (4-AAP) are prepared and characterized. Different physico-chemical methods like IR, magnetic and UV-Vis spectra are used to investigate the structure of these chelates. Fe(III) form 1:2 (M:catecholamines) chelates while Cu(II) form 1:1 chelates. Catecholamines behave as a bidentate mono- or dibasic ligands in binding to the metal ions. IR spectra show that the catecholamines are coordinated to the metal ions in a bidentate manner with O,O donor sites of the phenolic - OH. Magnetic moment measurements reveal the presence of Fe(III) chelates in octahedral geometry while the Cu(II) chelates are square planar. The thermal decomposition of Fe(III) and Cu(II) complexes is studied using thermogravimetric (TGA) and differential thermal analysis (DTA) techniques. The water molecules are removed in the first step followed immediately by decomposition of the ligand molecules. The activation thermodynamic parameters, such as, energy of activation, enthalpy, entropy and free energy change of the complexes are evaluated and the relative thermal stability of the complexes are discussed.

  7. Clinical monitoring and management of complications related to chelation therapy in patients with β-thalassemia.

    Science.gov (United States)

    Saliba, Antoine N; El Rassi, Fuad; Taher, Ali T

    2016-01-01

    Iron chelating agents - deferoxamine (DFO), deferiprone (DFP), and deferasirox (DFX) - are used to treat chronic iron overload in patients with β-thalassemia in an attempt to reduce morbidity and mortality related to siderosis. Each of the approved iron chelating agents has its own advantages over the others and also has its own risks, whether related to over-chelation or not. In this review, we briefly discuss the methods to monitor the efficacy of iron chelation therapy (ICT) and the evidence behind the use of each iron chelating agent. We also portray the risks and complications associated with each iron chelating agent and recommend strategies to manage adverse events. PMID:26613264

  8. Combinational chelation therapy abrogates lead-induced neurodegeneration in rats

    International Nuclear Information System (INIS)

    Lead, a ubiquitous and potent neurotoxicant causes oxidative stress which leads to numerous neurobehavioral and physiological alterations. The ability of lead to bind sulfhydryl groups or compete with calcium could be one of the reasons for its debilitating effects. In the present study, we addressed: i) if chelation therapy could circumvent the altered oxidative stress and prevent neuronal apoptosis in chronic lead-intoxicated rats, ii) whether chelation therapy could reverse biochemical and behavioral changes, and iii) if mono or combinational therapy with captopril (an antioxidant) and thiol chelating agents (DMSA/MiADMSA) is more effective than individual thiol chelator in lead-exposed rats. Results indicated that lead caused a significant increase in reactive oxygen species, nitric oxide, and intracellular free calcium levels along with altered behavioral abnormalities in locomotor activity, exploratory behavior, learning, and memory that were supported by changes in neurotransmitter levels. A fall in membrane potential, release of cytochrome c, and DNA damage indicated mitochondrial-dependent apoptosis. Most of these alterations showed significant recovery following combined therapy with captopril with MiADMSA and to a smaller extend with captopril + DMSA over monotherapy with these chelators. It could be concluded from our present results that co-administration of a potent antioxidant (like captopril) might be a better treatment protocol than monotherapy to counter lead-induced oxidative stress. The major highlight of the work is an interesting experimental evidence of the efficacy of combinational therapy using an antioxidant with a thiol chelator in reversing neurological dystrophy caused due to chronic lead exposure in rats.

  9. Sequestering agent for uranyl chelation: new bi-naphtyl ligands

    International Nuclear Information System (INIS)

    The synthesis of phosphonate, sulfocatecholamide (CAMS) and hydroxy-pyridinone (HOPO) bi-naphtyl ligands is presented. Their binding abilities for uranyl cation were determined by UV spectrophotometry in aqueous media versus pH. These titrations showed that the efficiency of these chelating agents depends on the nature of the chelating group. Each ligand shows a more or less pronounced affinity towards uranium. While the bis-phosphonate compound did not show any affinity towards the uranyl ion, the BINHOPO derivative exhibits significant affinity at acidic and neutral pH while the BINCAMS is more efficient at basic pH. (authors)

  10. SEPARATION OF PLUTONIUM FROM LANTHANUM BY CHELATION-EXTRACTION

    Science.gov (United States)

    James, R.A.; Thompson, S.G.

    1958-12-01

    Plutonium can be separated from a mixture of plutonlum and lanthanum in which the lanthanum to plutonium molal ratio ls at least five by adding the ammonium salt of N-nitrosoarylhydroxylamine to an aqueous solution having a pH between about 3 and 0.2 and containing the plutonium in a valence state of at least +3, to form a plutonium chelate compound of N-nitrosoarylhydroxylamine. The plutonium chelate compound may be recovered from the solution by extracting with an immiscible organic solvent such as chloroform.

  11. Chelation therapy in intoxications with mercury, lead and copper

    DEFF Research Database (Denmark)

    Cao, yang; Skaug, Marit Aralt; Andersen, Ole;

    2015-01-01

    In the present review we provide an update of the appropriate use of chelating agents in the treatment of intoxications with compounds of mercury, lead and copper. The relatively new chelators meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-propanesulphonate (DMPS) can effectively...... mobilize deposits of mercury as well as of lead into the urine. These drugs can be administered orally and have relatively low toxicity compared to the classical antidote dimercaptopropanol (BAL). d-Penicillamine has been widely used in copper overload, although 2,3-dimercaptosuccinic acid or...

  12. Physiological response of Moringa oleifera to stigmasterol and chelated zinc

    OpenAIRE

    KARIMA GAMAL EL-DIN; IMAN MAHMOUD TALAAT; MOHAMED ABDEL-GHANY BEKHETA; ABDALLA EL-MOURSI

    2012-01-01

    El-Moursi A, Talaat IM, Bekheta MA, Gamal El-Din K. 2012. Physiological response of Moringa oleifera to stigmasterol and chelated zinc. Nusantara Bioscience 4: 118-123. Two pot experiments were carried out in the screen of the National Research Centre, Dokki, Giza, Egypt, during two successive seasons (2009/2010 and 2010/2011), respectively to study the effect of foliar spray with chelated zinc (100, 200 and 300 mg/L) and stigmasterol (50, 100 and 150 mg/L) on growth and chemical constituents...

  13. Metal complexes of 2((ethylthio)methyl)-4-aminophenol as oxidation inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Rarog, B.G.; Ivanov, V.A.; Potekhin, V.M.; Nesterov, M.V.

    1983-07-10

    Interest in the use of complex compounds as inhibitors of liquid-phase oxidation of hydrocarbons has increased in recent years. Sulfur- and nitrogen-containing metal complexes are known whose inhibiting properties are determined to a considerable extent by the composition of the chelate system, the nature of the metal, and the structure of the complex. At the same time, there is no information on metal compounds whose molecules contain functional groups not included in the chelate system but capable of taking part in inhibition reactions, and there are no data on the possible influence of the metal in the chelate system on the antioxidant activity of these groups. Accordingly, the inhibiting properties of metal complexes of 2((ethylthio)-methyl)-4-aminophenol, having a free amino group, in liquid-phase oxidation of hydrocarbons were studied. Decalin was chosen as the model oxidizable compound in studies of the antioxidant action of metal chelates.

  14. Extraction of uranium from soil using selective chelators with secondary concentration using water soluble polymers

    International Nuclear Information System (INIS)

    Studies have investigated the extraction and recovery of uranium from contaminated soil containing both sorbed and metallic uranium. Our goal was to selectively bind and recover uranium from this soil and minimize secondary waste generation. Our approach was to determine optimal chelators for uranium extraction using contaminated soil taken from an area at LANL where open air testing of explosives containing depleted uranium was conducted. Uranium concentrations range in the soil from 1000-5000ppm. We have found that equimolar carbonate/bicarbonate solution in conjunction with an oxidant, sodium hypochlorite, is an excellent extractant for uranium from this soil, removing 90+% of the uranium. Our present focus is on the recovery and concentration of uranium from the extractant solution using a large water soluble polymer (>10,000 MW) as a secondary chelator for complexing the extracted uranium:carbonate complex. Using ultrafiltration, the volume of waste can be reduced 100+ fold. These commercially available polymers can then be regenerated and re-used. Using this approach, we are able to recover 90+% of the uranium in a minimal volume

  15. Neuroprotective Role of a Novel Copper Chelator against Aβ42 Induced Neurotoxicity

    Directory of Open Access Journals (Sweden)

    Sandeep Kumar Singh

    2013-01-01

    Full Text Available Alzheimer's disease (AD is a progressive neurodegenerative disease and associated with the extracellular deposits of amyloid-β peptide in hippocampus region. Metal ions like Cu, Fe and Zn are known to associate with the amyloid beta (Aβ at high concentration and interaction of these ions with soluble and aggregated forms of Aβ peptide help in development of AD. Here we showed Cu mediated neurotoxicity in the eye tissues of transgenic Drosophila expressing human amyloid β and its rescue through a novel Cu chelator. In this context, we have synthesised and characterized the compound L 2,6-Pyridinedicarboxylic acid, 2,6-bis[2-[(4-carboxyphenyl methylene] hydrazide] by Mass spectra (MS and Elemental analysis (EA. The Cu chelation potential of the compound L is tested in vivo in Drosophila. Oral administration of Copper to the transgenic larvae resulted in severe degeneration in eye tissues, which was rescued by the supplementation of compound L. The levels of anti-oxidant markers like SOD and MDA were measured in compound L treated flies and found a significant rescue (P<0.001. Further rescue of the eye degeneration phenotypes as revealed by SEM affirm the role of copper in Aβ toxicity. Hence, use of compound L, an amidoamine derivative, could be a possible therapeutic measure for Aβ induced neurotoxicity.

  16. Questions and Answers: The NIH Trial of EDTA Chelation Therapy for Coronary Heart Disease

    Science.gov (United States)

    ... NIH Trial of EDTA Chelation Therapy for Coronary Heart Disease Preliminary results from the Trial to Assess Chelation ... and complete it. Study Background What is coronary heart disease? Coronary heart disease (CHD) is the most common ...

  17. Iron chelating active packaging: Influence of competing ions and pH value on effectiveness of soluble and immobilized hydroxamate chelators.

    Science.gov (United States)

    Ogiwara, Yoshiko; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2016-04-01

    Many packaged foods utilize synthetic chelators (e.g. ethylenediaminetetraacetic acid, EDTA) to inhibit iron-promoted oxidation or microbial growth which would result in quality loss. To address consumer demands for all natural products, we have previously developed a non-migratory iron chelating active packaging material by covalent immobilization of polyhydroxamate and demonstrated its efficacy in delaying lipid oxidation. Herein, we demonstrate the ability of this hydroxamate-functionalized iron chelating active packaging to retain iron chelating capacity; even in the presence of competing ions common in food. Both immobilized and soluble hydroxamate chelators retained iron chelating capacity in the presence of calcium, magnesium, and sodium competing ions, although at pH 5.0 the presence of calcium reduced immobilized hydroxamate iron chelation. A strong correlation was found between colorimetric and mass spectral analysis of iron chelation by the chelating packaging material. Such chelating active packaging may support reducing additive use in product formulations, while retaining quality and shelf life. PMID:26593563

  18. MDs remain sceptical as chelation therapy goes mainstream in Saskatchewan

    OpenAIRE

    Oliver, M.

    1997-01-01

    The College of Physicians and Surgeons of Saskatchewan recently agreed to allow physicians to administer chelation therapy. Supporters, relying on anecdotal evidence, say it works wonders in overcoming heart disease, but many physicians remain profoundly sceptical. In Saskatchewan, the college decision has proved popular with patients but has drawn an angry reaction from doctors.

  19. Role of Chelation During Pregnancy in the Lead Poisoned Patient

    OpenAIRE

    Brown, Mary Jean

    2013-01-01

    Cultural and environmental factors can cause lead poisoning in the pregnant patient. The data regarding the reproductive risks associated with chelation during human pregnancy are sparse. Assessment of the exposure setting, including anticipatory counseling for each pregnant woman, would help assure the ideal outcome of no added lead intake.

  20. Reversal of haemochromatotic cardiomyopathy in beta thalassaemia by chelation therapy.

    OpenAIRE

    Politi, A; M. Sticca; Galli, M

    1995-01-01

    Haemochromatotic cardiomyopathy is the main cause of morbidity and mortality in patients with beta thalassaemia major. Once congestive heart failure develops most patients die in a few months. Congestive heart failure was reversed and echocardiographic findings were restored to normal in a 24 year old woman with beta thalassaemia who resumed treatment with chelation therapy (desferrioxamine).

  1. Quantitative determination of chelators and their degradation products in mixed hazardous wastes from tank 241-SY-101 using derivatization GC/MS

    International Nuclear Information System (INIS)

    Considerable attention has been focused on chelators such as ethylenediaminetetraacetic acid (EDTA) and N-(hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), which form water-soluble complexes with most heavy metals. Most radionuclides are included in this class of constituents. As a result, chelator complexes have become very important environmentally because of their tendency to enhance the mobility of heavy metals through the soil and potentially contaminate groundwater. In addition, there is correlation between chelator concentration and crust formation/gas release. The chelators are a class of compounds whose low volatility and high polarity preclude analysis by gas chromatography/mass spectrometry (GC/MS) without prior derivatization. Waste sample from a double-shell storage tank at Hanford were derivatized with BF3/methanol and analyzed using GC/MS. Results indicate the presence of EDTA, HEDTA, nitrilotriacetic (NTA), and citric acid. Nitrosoiminodiacetic acid was identified and determined to be an artifact of the derivatization procedure; it is assumed to arise from nitrosation of iminodiacetic acid in the waste sample. (author)

  2. f-Element Ion Chelation in Highly Basic Media

    International Nuclear Information System (INIS)

    A large body of data has been collected over the last fifty years on the chemical behavior of f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueous solutions that produce poorly understood oxide-hydroxide species; therefore, most of the fundamental f-element solution chemistry has allowed synthetic and separations chemists to rationally design advanced organic chelating ligands useful for highly selective partitioning and separation of f-element ions from complex acidic solution matrices. These ligands and new examples under development allow for the safe use and treatment of solutions containing highly radioactive species. This DOE/EMSP project was undertaken to address the following fundamental objectives: (1) study the chemical speciation of Sr and lanthanide (Ln) ions in basic aqueous media containing classical counter anions found in waste matrices; (2) prepare pyridine N-oxide phosphonates and phosphonic acids that might act as selective chelators for Ln ions in model basic pH waste streams; (3) study the binding of the new chelators toward Ln ions and (4) examine the utility of the chelators as decontamination and dissolution agents under basic solution conditions. The project has been successful in attacking selected aspects of the very difficult problems associated with basic pH solution f-element waste chemistry. In particular, the project has (1) shed additional light on the initial stages of Ln ion sol-gel-precipitate formulation under basic solution conditions; (2) generated new families of pyridine phosphonic acid chelators; (3) characterized the function of the chelators and (4) examined their utility as oxide-hydroxide dissolution agents. These findings have contributed significantly to an improved understanding of the behavior of Ln ions in basic media containing anions found in typical waste sludges as well as to the development of sludge dissolution agents. The new chelating reagents are easily made and could be

  3. Chelator induced phytoextraction and in situ soil washing of Cu

    International Nuclear Information System (INIS)

    In a soil column experiment, we investigated the effect of 5 mmol kg-1 soil addition of citric acid, ethylenediamine tetraacetate (EDTA), diethylenetriamine-pentaacetate (DTPA) and [S,S]-stereoisomer of ethylenediamine-disuccinate (EDDS) on phytoextraction of Cu from a vineyard soil with 162.6 mg kg-1 Cu, into the test plant Brassica rapa var. pekinensis. We also examined the use of a horizontal permeable barrier, composed of layers of nutrient enriched sawdust and apatite, for reduction of chelator induced Cu leaching. The addition of all chelators, except citric acid, enhanced Cu mobility and caused leaching of 19.5-23% of initial total Cu from the soil column. However, Cu plant uptake did not increase accordingly; the most effective was the EDDS treatment, in which plant Cu concentration reached 37.8±1.3 mg kg-1 Cu and increased by 3.3-times over the control treatment. The addition of none of the chelators in the concentration range from 5 to 15 mmol kg-1 exerted any toxic effect on respiratory soil microorganisms. When EDDS was applied into the columns with horizontal permeable barriers, only 0.53±0.32% of the initial total Cu was leached. Cu (36.7%) was washed from the 18 cm soil layer above the barrier and accumulated in the barrier. Our results indicate that rather than for a reduction of Cu leaching during rather ineffective chelate induced Cu phytoextraction, horizontal permeable barriers could be more effective in a new remediation technique of controlled in situ soil washing of Cu with biodegradable chelates

  4. Chelator induced phytoextraction and in situ soil washing of Cu

    Energy Technology Data Exchange (ETDEWEB)

    Kos, Bostjan; Lestan, Domen

    2004-11-01

    In a soil column experiment, we investigated the effect of 5 mmol kg{sup -1} soil addition of citric acid, ethylenediamine tetraacetate (EDTA), diethylenetriamine-pentaacetate (DTPA) and [S,S]-stereoisomer of ethylenediamine-disuccinate (EDDS) on phytoextraction of Cu from a vineyard soil with 162.6 mg kg{sup -1} Cu, into the test plant Brassica rapa var. pekinensis. We also examined the use of a horizontal permeable barrier, composed of layers of nutrient enriched sawdust and apatite, for reduction of chelator induced Cu leaching. The addition of all chelators, except citric acid, enhanced Cu mobility and caused leaching of 19.5-23% of initial total Cu from the soil column. However, Cu plant uptake did not increase accordingly; the most effective was the EDDS treatment, in which plant Cu concentration reached 37.8{+-}1.3 mg kg{sup -1} Cu and increased by 3.3-times over the control treatment. The addition of none of the chelators in the concentration range from 5 to 15 mmol kg{sup -1} exerted any toxic effect on respiratory soil microorganisms. When EDDS was applied into the columns with horizontal permeable barriers, only 0.53{+-}0.32% of the initial total Cu was leached. Cu (36.7%) was washed from the 18 cm soil layer above the barrier and accumulated in the barrier. Our results indicate that rather than for a reduction of Cu leaching during rather ineffective chelate induced Cu phytoextraction, horizontal permeable barriers could be more effective in a new remediation technique of controlled in situ soil washing of Cu with biodegradable chelates.

  5. Geochemically structural characteristics of municipal solid waste incineration fly ash particles and mineralogical surface conversions by chelate treatment.

    Science.gov (United States)

    Kitamura, Hiroki; Sawada, Takaya; Shimaoka, Takayuki; Takahashi, Fumitake

    2016-01-01

    Leaching behaviors of heavy metals contained in municipal solid waste incineration (MSWI) fly ash have been studied well. However, micro-characteristics of MSWI fly ash particles are still uncertain and might be non-negligible to describe their leaching behaviors. Therefore, this study investigated micro-characteristics of MSWI fly ash particles, especially their structural properties and impacts of chelate treatment on surface characteristics. According to SEM observations, raw fly ash particles could be categorized into four types based on their shapes. Because chelate treatment changed the surface of fly ash particles dramatically owing to secondary mineral formations like ettringite, two more types could be categorized for chelate-treated fly ash particles. Acid extraction experiments suggest that fly ash particles, tested in this study, consist of Si-base insoluble core structure, Al/Ca/Si-base semi-soluble matrices inside the body, and KCl/NaCl-base soluble aggregates on the surface. Scanning electron microscope (SEM) observations of the same fly ash particles during twice moistening treatments showed that KCl/NaCl moved under wet condition and concentrated at different places on the particle surface. However, element mobility depended on secondary mineral formations. When insoluble mineral like gypsum was generated and covered the particle surface, it inhibited element transfer under wet condition. Surface characteristics including secondary mineral formation of MSWI fly ash particles are likely non-negligible to describe trace element leaching behaviors. PMID:26336844

  6. The magnesium chelation step in chlorophyll biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, J.D.

    1991-01-01

    The biogenesis of energy transducing membranes requires the coordinate synthesis of prosthetic groups, proteins and lipids. Two of the major prosthetic groups, chlorophyll and heme, share a common biosynthetic pathway that diverges at the point of metal insertion into protoporphyrin IX. Insertion of iron leads to heme, while insertion of magnesium leads to chlorophyll. The Mg-chelatase from intact cucumber chloroplasts has been characterized with regard to substrate specificity, regulation, ATP requirement, and a requirement for intact chloroplasts. Mg-chelatase was isolated from maize, barley and peas and characterized in order to circumvent the intact chloroplast requirement of cucumber Mg-chelatase. Pea Mg-chelatase activity is higher than cucumber Mg-chelatase activity, and lacks the requirement for intact chloroplasts. Studies on isolated pea Mg-chelatase have shown more cofactors are required for the reaction than are seen with ferrochelatase, indicating a greater opportunity for regulatory control of this pathway. Two of the cofactors are proteins, and there appears to be a requirement for a protease-sensitive component which is outside the outer envelope. We are developing a continuous spectrophotometric assay for Mg-chelatase activity, and an assay for free heme which has shown heme efflux from intact chloroplasts. 18 refs. (MHB)

  7. Examining the fixation kinetics of chelated and non-chelated copper micronutrient and the applications to micronutrient management in semi-arid alkaline soils

    OpenAIRE

    T. K. Udeigwe; M. B. Eichmann; Menkiti, M. C.

    2015-01-01

    The relationship between the deficiency of a nutrient in plants and its total concentration in the soil is complex. This study examined and compared the fixation and fixation kinetics of copper (Cu) in chelated (Ethylene diamine tetraacetic acid, EDTA) and non-chelated mixed systems of micronutrients in the semi-arid soils of the Southern High Plains, US using findings from Cu extraction studies and kinetic models. Approximately, 22 % more Cu was fixed in the non-chelated system with...

  8. Examining the fixation kinetics of chelated and non-chelated copper and the applications to micronutrient management in semiarid alkaline soils

    Science.gov (United States)

    Udeigwe, T. K.; Eichmann, M. B.; Menkiti, M. C.; Kusi, N. Y. O.

    2016-02-01

    This study examined and compared the fixation and fixation kinetics of copper (Cu) in chelated (ethylene diamine tetraacetic acid, EDTA) and non-chelated mixed systems of micronutrients in the semiarid soils of the Southern High Plains, USA, using findings from Cu extraction studies and kinetic models. Approximately, 22 % more Cu was fixed in the non-chelated system compared to the chelated within the first 14 days with only 7 % difference between the two systems by day 90. Findings suggest a decrease in the effectiveness of chelated micronutrients over time, highlighting the significance of timing even when chelated micronutrients are used. The strengths of the relationship of change in available Cu with respect to other micronutrients (iron (Fe), manganese (Mn), and zinc (Zn)) were higher in the non-chelated system (R2: 0.68-0.94), compared to the chelated (R2: 0.42-0.81), with slopes of 0.40 (Cu-Fe), 0.31 (Cu-Mn), and 1.04 (Cu-Zn) in the non-chelated system and 0.26 (Cu-Fe), 0.22 (Cu-Mn), and 0.90 (Cu-Zn) in the chelated system. Reduction in the amount of available Cu was best described by the power function model (R2 = 0.91, SE = 0.081) in the non-chelated system and second-order model (R2 = 0.95, SE = 0.010) in the chelated system. The applications generated from this study could be used as tools for improved micronutrient management and also provide baseline data for future work in other semiarid/arid alkaline soils of the world. Findings are also more applicable to field settings, an improvement over related previous studies.

  9. New hydroxypyridinone-functionalized sepharoses as sorbing agents for hard metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Grazina, Raquel [Centro Quimica Estrutural, Instituto Superior Tecnico-UTL, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Faculdade de Ciencias e Tecnologia, UNL, Departamento Quimica, REQUIMTE, CQFB, 2829-516 Caparica (Portugal); Santos, M. Amelia, E-mail: masantos@ist.utl.pt [Centro Quimica Estrutural, Instituto Superior Tecnico-UTL, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2011-02-28

    Two new polymeric matrices functionalized with 3-hydroxy-4-pyridinone chelating units (HP-NH-SEPH and HP-C=NH-SEPH) have been prepared and studied for their chelating ability towards a set of metal ions (e.g. Fe(III), Al(III), and Th(IV)). Both matrices demonstrated excellent ability to complex these metal ions, but HP-NH-SEPH evidenced higher chelating capacity than HP-C=NH-SEPH. The corresponding metal-complex gels presented high stability in the pH range 3-7, and their chelating capacity followed the order, Fe(III) {approx} Th(IV) > Al(III), in agreement with previously reported thermodynamics of the corresponding monomeric ligand-metal complexes in aqueous solution. These functionalized supports also showed capacity to be regenerated and reused. Thus, there are good perspectives for potential environmental and medical applications of these new metal sorbents.

  10. Macrocyclic chelator-coupled gastrin-based radiopharmaceuticals for targeting of gastrin receptor-expressing tumours

    International Nuclear Information System (INIS)

    Diethylenetriamine-pentaacetic acid (DTPA)-coupled minigastrins are unsuitable for therapeutic application with the available β-emitting radiometals due to low complex stability. Low tumour-to-kidney ratio of the known radiopharmaceuticals is further limiting their potency. We used macrocyclic chelators for coupling to increase complex stability, modified the peptide sequence to enhance radiolytic stability and studied tumour-to-kidney ratio and metabolic stability using 111In-labelled derivatives. Gastrin derivatives with decreasing numbers of glutamic acids were synthesised using 111In as surrogate for therapeutic radiometals for in vitro and in vivo studies. Gastrin receptor affinities of the natIn-metallated compounds were determined by receptor autoradiography using 125I-CCK as radioligand. Internalisation was evaluated in AR4-2J cells. Enzymatic stability was determined by incubating the 111In-labelled peptides in human serum. Biodistribution was performed in AR4-2J-bearing Lewis rats. IC50 values of the natIn-metallated gastrin derivatives vary between 1.2 and 4.8 nmol/L for all methionine-containing derivatives. Replacement of methionine by norleucine, isoleucine, methionine-sulfoxide and methionine-sulfone resulted in significant decrease of receptor affinity (IC50 between 9.9 and 1,195 nmol/L). All cholecystokinin receptor affinities were >100 nmol/L. All 111In-labelled radiopeptides showed receptor-specific internalisation. Serum mean-life times varied between 2.0 and 72.6 h, positively correlating with the number of Glu residues. All 111In-labelled macrocyclic chelator conjugates showed higher tumour-to-kidney ratios after 24 h (0.37-0.99) compared to 111In-DTPA-minigastrin 0(0.05). Tumour wash out between 4 and 24 h was low. Imaging studies confirmed receptor-specific blocking of the tumour uptake. Reducing the number of glutamates increased tumour-to-kidney ratio but resulted in lower metabolic stability. The properties of the macrocyclic chelator

  11. Synthesis of New Bis(3-hydroxy-4-pyridinone) Ligands as Chelating Agents for Uranyl Complexation

    OpenAIRE

    Bo Jin; Rongzong Zheng; Rufang Peng; Shijin Chu

    2016-01-01

    Five new bis(3-hydroxy-4-pyridinone) tetradentate chelators were synthesized in this study. The structures of these tetradentate chelators were characterized by 1H-NMR, 13C-NMR, FT-IR, UV-vis, and mass spectral analyses. The binding abilities of these tetradentate chelators for uranyl ion at pH 7.4 were also determined by UV spectrophotometry in aqueous media. Results showed that the efficiencies of these chelating agents are dependent on the linker length. Ligand 4b is the best chelator and ...

  12. Synthesis of New Bis(3-hydroxy-4-pyridinone) Ligands as Chelating Agents for Uranyl Complexation.

    Science.gov (United States)

    Jin, Bo; Zheng, Rongzong; Peng, Rufang; Chu, Shijin

    2016-01-01

    Five new bis(3-hydroxy-4-pyridinone) tetradentate chelators were synthesized in this study. The structures of these tetradentate chelators were characterized by ¹H-NMR, (13)C-NMR, FT-IR, UV-vis, and mass spectral analyses. The binding abilities of these tetradentate chelators for uranyl ion at pH 7.4 were also determined by UV spectrophotometry in aqueous media. Results showed that the efficiencies of these chelating agents are dependent on the linker length. Ligand 4b is the best chelator and suitable for further studies. PMID:27005598

  13. Adsorption of Cu(II), Hg(II), and Ni(II) ions by modified natural wool chelating fibers

    International Nuclear Information System (INIS)

    The graft copolymerization of ethyl acrylate (EA) onto natural wool fibers initiated by potassium persulphate and Mohr's salt redox initiator system in limited aqueous medium was carried out in heterogeneous media. Ester groups of the grafted copolymers were partially converted into hydrazide function groups followed by hydrazone formation through reaction with isatin. Also the application of the modified fibers for metal ion uptake was studied using Cu(II), Hg(II) and Ni(II). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.

  14. Adsorption of Cu(II), Hg(II), and Ni(II) ions by modified natural wool chelating fibers

    Energy Technology Data Exchange (ETDEWEB)

    Monier, M., E-mail: monierchem@yahoo.com [Chemistry Department, Drexel University, Philadelphia, PA (United States); Chemistry Department, Faculty of Science, Mansoura University, Mansoura (Egypt); Ayad, D.M.; Sarhan, A.A. [Chemistry Department, Faculty of Science, Mansoura University, Mansoura (Egypt)

    2010-04-15

    The graft copolymerization of ethyl acrylate (EA) onto natural wool fibers initiated by potassium persulphate and Mohr's salt redox initiator system in limited aqueous medium was carried out in heterogeneous media. Ester groups of the grafted copolymers were partially converted into hydrazide function groups followed by hydrazone formation through reaction with isatin. Also the application of the modified fibers for metal ion uptake was studied using Cu(II), Hg(II) and Ni(II). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.

  15. Adsorption of Cu(II), Hg(II), and Ni(II) ions by modified natural wool chelating fibers.

    Science.gov (United States)

    Monier, M; Ayad, D M; Sarhan, A A

    2010-04-15

    The graft copolymerization of ethyl acrylate (EA) onto natural wool fibers initiated by potassium persulphate and Mohr's salt redox initiator system in limited aqueous medium was carried out in heterogeneous media. Ester groups of the grafted copolymers were partially converted into hydrazide function groups followed by hydrazone formation through reaction with isatin. Also the application of the modified fibers for metal ion uptake was studied using Cu(II), Hg(II) and Ni(II). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction. PMID:19962235

  16. Mixed chelates of some trivalent lanthanide ions containing (trans-1,2-cyclohexylenedinitrilo)tetraacetate and norleucinate

    International Nuclear Information System (INIS)

    Formation constants of mixed chelates with (trans-1,2-cyclohexylenedinitrilo)tetra-acetate (DCTA) as primary ligand and norleucinate (nle) as secondary ligand with metal ions La(III), Ce(III), Pr(III), Sm(III), Gd(III), Tb(III), Dy(III), Er(III), and Yb(III) have been determined by the modified potentiometric pH titration method of Irving-Rossotti in aqueous medium at (295 ± 1) K and fixed ionic strenght of μ=0.1 M (NaClO4). Formation constants of binary complexes of the metal ions with the secondary ligand have also been determined under identical conditions. The mixed chelates were found to be more stable than the binary ones. The order of stabilities in terms of metal ions is La(III)< Ce(III)< Pr(III)< Sm(III)< Gd(III)< Tb(III)< Dy(III)< Er(III)< Yb(III) for binary and ternary complexes with a prominent 'Gadolinium break'. (authors)

  17. A comparison study of radiostrontium chelation with chitin, chitosan, EDTA and DTPA

    International Nuclear Information System (INIS)

    Chitin and chitosan are nontoxic natural chelators that chelate radiostrontium effectively. The purpose of this study was to compare radiostrontium chelation of chitin and chitosan with that of well known chemical chelators, namely EDTA and DTPA. The chelaton rates of chitin, chitosan, EDTA and DTPA were compared using a column chromatography method (Sephadex G-25M, Sweden). Three kinds of chitins and four kinds of chitosans were used. All of them were water soluble. Phosphated chitosan showed the highest chelation yield of 97% at pH 7. All of chitins, chitosans, EDTA and DTPA showed chelation yield of more than 90% independent of varing pH level. Chitin and chitosan have similar chelation rate as compared with EDTA and DTPA

  18. Conformational study of aromatic ketones: chemical shift reagents: uranium chelates

    International Nuclear Information System (INIS)

    A series of benzophenones, 2-benzoyl thiophenes and 2-benzoyl pyridines, all substituted at the benzene ring by an amino acid chain, have been synthesised with the object of examining to what extent the site of the aminoacid chain and the site and nature of the other substituents modify the electronic structure of the molecule and the orientation of each ring with respect to the plane of the carbonyl group. In the second part a study of paramagnetic cations, in particular of uranium, which is able to form stable chelates with beta-diketones was carried out to study their complexing power. The chelates studied are the (hexafluoropentanedionate)4U, the (heptafluorodimethyloctanedionate)4U and the (trifluorophenylbutanedionate)4U

  19. Doping of graphene nanomeshes by ion-chelation

    Science.gov (United States)

    Maarouf, Ahmed; Nistor, Razvan; Afzali, Ali; Kuroda, Marcelo; Newns, Dennis; Martyna, Glenn

    2013-03-01

    Graphene nanomeshes (GNM's) are formed by the creation of a superlattice of pores in graphene. Depending upon the pore shape, size, superlattice constant and symmetry, GNM's can be semimetallic, or semiconducting with a fractional eV band gap, allowing them to be fruitfully employed in applications that pristine graphene cannot. In this work, first principles calculations are used to study the doping of semiconducting GNM's using a chemically motivated approach. It is shown that ion-chelation leads to a stable doping of the GNM's, and that it occurs within a rigid band doping picture. Such chelated or ``crown'' GNM structures are thus stable, high mobility semiconducting materials which can serve as building blocks for novel graphene-based nanoelectronics applications.

  20. Chelation studies involving decontamination of light lanthanides by polyaminopolycarboxylic

    International Nuclear Information System (INIS)

    The present thesis constitutes chelation studies involving decontamination of light lanthanides, cobalt , and uranium with 2,2-bis-acryloyliminomethylene- acid (BAETA) using the spectrophotometric method. the work carried out aimed to clear up the effectiveness of BAETA as a decontaminating agent for radioactive nuclides from human body . the thesis includes a general introduction , outlines the aim of work and contains three main chapters . the results of the work are discussed at the end of the thesis. the first chapter deals with a comprehensive survey of the relevant literature. this includes the metabolism and toxicity of cerium, uranium, cobalt and Ln+3 elements, general methodologies of internal decontamination, choice and effectiveness of chelating agents

  1. Lanthanides caged by the organic chelates; structural properties

    Science.gov (United States)

    Smentek, Lidia

    2011-04-01

    The structure, in particular symmetry, geometry and morphology of organic chelates coordinated with the lanthanide ions are analyzed in the present review. This is the first part of a complete presentation of a theoretical description of the properties of systems, which are widely used in technology, but most of all, in molecular biology and medicine. The discussion is focused on the symmetry and geometry of the cages, since these features play a dominant role in the spectroscopic activity of the lanthanides caged by organic chelates. At the same time, the spectroscopic properties require more formal presentation in the language of Racah algebra, and deserve a separate analysis. In addition to the parent systems of DOTA, DOTP, EDTMP and CDTMP presented here, their modifications by various antennas are analyzed. The conclusions that have a strong impact upon the theory of the energy transfer and the sensitized luminescence of these systems are based on the results of numerical density functional theory calculations.

  2. Improved paramagnetic chelate for molecular imaging with MRI

    Science.gov (United States)

    Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

    2005-05-01

    The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent.

  3. Improved paramagnetic chelate for molecular imaging with MRI

    International Nuclear Information System (INIS)

    The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent

  4. Treatment of some radioactive wastes by using new chelating membranes

    International Nuclear Information System (INIS)

    The preparation of chelating membranes containing nitrile and carboxylic acid as functional groups was investigated. The modification of such membranes by chemical treatments to produce significant changes in their properties was studied. This modification results in a higher rate of exchange and higher capacity. The applicability of such modified membranes in the removal of Co-60 and Cs-137 from their wastes were tested. The dependence of these radioactive nuclides uptake on the time and degree of grafting for H CI-, NH2OH-and KOH-treated membranes was investigated. It was found that the adsorption rate and capacity were higher for KOH-treated membrane than those for the NH2OH and H CI treated ones. The prepared grafted membranes have a good affinity towards the adsorption or chelation with Co-60 and Cs-137. This result may make such prepared materials acceptable for practicable use in some radioactive waste treatments and recovery

  5. Pathophysiological and clinical aspects of iron chelation therapy in MDS.

    Science.gov (United States)

    Gattermann, Norbert

    2012-01-01

    The majority of patients with myelodysplastic syndromes (MDS) become transfusion-dependent during the course of disease and may thus develop transfusional iron overload. As a further contributor to iron overload there is increased absorption of dietary iron from the gut, as a consequence of ineffective erythropoiesis. Compared with thalassemia, it is less clear how frequent patients with MDS develop clinical complications of iron overload, and whether the accumulation of iron shortens their survival. This review aims to summarize our current knowledge of the detrimental effects of transfusional iron overload in MDS, point out the risks associated with iron-induced oxidative stress, describe the tools available for diagnosing iron overload, indicate the treatment options with currently available iron chelators, and discuss the measurement of labile plasma iron (LPI) as a tool to monitor the efficacy of iron chelation therapy. PMID:22571702

  6. Toxicological studies of a new chelating agent 8102

    International Nuclear Information System (INIS)

    The results of toxicological studies of a new chelating agent 8102 in different kinds of animals (mice, rats, rabbits and dogs) were reported. The results show that for mice, LD50 is 782 +- 21 mg/kg (i.v) and 3.17 +- 0.06 g/kg (i.m), and for rats, LD50 is 478 +- 15 mg/kg (i.v) and 3.04 +- 0.08 g/kg (i.m). In subacute experiments for dogs, the agent 8102 in doses of 50, 100, 150 mg(kg.day) was injected i.m. and for control group 0.9% saline was injected i.m.. Treatment was continued for 30 days. In pathological and clinical chemical analysis no essential change was observed. The experimental results suggest that the toxicity of this new chelating agent 8102 is low

  7. 2013 METALS IN BIOLOGY GORDON RESEARCH CONFERENCE, JANUARY 20-25, 2013

    Energy Technology Data Exchange (ETDEWEB)

    Rosenzweig, Amy

    2013-01-25

    Typical topics for lectures and posters include: biochemical and biophysical characterization of new metal containing proteins, enzymes, nucleic acids, factors, and chelators from all forms of life; synthesis, detailed characterization, and reaction chemistry of biomimetic compounds; novel crystal and solution structures of biological molecules and synthetic metal-chelates; discussions of the roles that metals play in medicine, maintenance of the environment, and biogeochemical processes; metal homeostasis; application of theory and computations to the structure and mechanism of metal-containing biological systems; and novel applications of spectroscopy to metals in biological systems.

  8. Meta-analysis of the safety of iron chelating agents

    OpenAIRE

    Li, Niya; 李妮婭

    2014-01-01

    Background: Thalassaemia is a genetic disorder disease, one of the most clinically relevant haemoglobinopathies in paediatric population. It interferes with the synthesis of haemoglobin chain. For the sake of maintaining the serum haemoglobin at a normal level, regular blood cell transfusion is required to the patients with thalassaemia. In general, patients with thalassaemia are often diagnosed at an early age and need to take a life-long iron chelating therapy to prevent the multi-organ...

  9. Studies on the chelation of aluminium for biological application

    International Nuclear Information System (INIS)

    Potentiometric determinations of the strength of chelation of aluminium(III) by citrate and 3-carboxy-1,5-pentanedioic acid have been made at 37,0 plus minus 0,1 degree Celsius and I = 150 mmol dm-3 NaCl. From these results, the citrate complex is inferred to be tridentate with coordination through the two terminal carboxyl groups and the central hydroxyl group. This structure is confirmed by 13C nuclear magnetic resonance

  10. CHELATION THERAPY FOR IRON OVERLOAD: NURSING PRACTICE IMPLICATIONS

    OpenAIRE

    Eckes, Ellen J.

    2011-01-01

    Many diseases of the blood are treated with blood transfusion therapy. Chronic transfusions can cause iron overload, and, if untreated, can cause end-organ damage. Chelation therapy provides a way of treating iron overload and minimizing its adverse effects. Nurses need to understand that iron overload is a consequence of chronic blood transfusion, and they need to know what effects it has on end-organs and what treatment options are available.

  11. Self-assembled polymeric chelate nanoparticles as potential theranostic agents

    Czech Academy of Sciences Publication Activity Database

    Škodová, Michaela; Černoch, Peter; Štěpánek, Petr; Chánová, Eliška; Kučka, Jan; Kálalová, Zuzana; Kaňková, Dana; Hrubý, Martin

    2012-01-01

    Roč. 13, č. 18 (2012), s. 4244-4250. ISSN 1439-4235 R&D Projects: GA ČR GPP207/10/P054; GA ČR GA202/09/2078; GA ČR GAP304/12/0950 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : chelates * nanoparticles * polymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.349, year: 2012

  12. Decontamination of process equipment using recyclable chelating solvent

    Energy Technology Data Exchange (ETDEWEB)

    Jevec, J.; Lenore, C.; Ulbricht, S. [Babcock & Wilcox, Co., R& DD, Alliance, OH (United States)

    1995-10-01

    The Department of Energy (DOE) is now faced with the task of meeting decontamination and decommissioning obligations at numerous facilities by the year 2019. Due to the tremendous volume of material involved, innovative decontamination technologies are being sought that can reduce the volumes of contaminated waste materials and secondary wastes requiring disposal. This report describes the results of the performance testing of chelates and solvents for the dissolution of uranium.

  13. Examining the fixation kinetics of chelated and non-chelated copper micronutrient and the applications to micronutrient management in semi-arid alkaline soils

    Science.gov (United States)

    Udeigwe, T. K.; Eichmann, M. B.; Menkiti, M. C.

    2015-10-01

    The relationship between the deficiency of a nutrient in plants and its total concentration in the soil is complex. This study examined and compared the fixation and fixation kinetics of copper (Cu) in chelated (Ethylene diamine tetraacetic acid, EDTA) and non-chelated mixed systems of micronutrients in the semi-arid soils of the Southern High Plains, US using findings from Cu extraction studies and kinetic models. Approximately, 22 % more Cu was fixed in the non-chelated system within the first 14 days with only 7 % difference between the two systems by day 90. Findings suggest a decrease in the effectiveness of chelated micronutrient over time, highlighting the significance of timing even when chelated micronutrients are applied. The strengths of the relationship of change in available Cu with respect to other micronutrients [iron (Fe), manganese (Mn), and zinc (Zn)] were higher in the non-chelated system (R2: 0.68-0.94), compared to the chelated (R2: 0.42-0.81) with slopes of 0.40 (Cu-Fe), 0.31 (Cu-Mn), and 1.04 (Cu-Zn) in the non-chelated system and 0.26 (Cu-Fe), 0.22 (Cu-Mn), and 0.90 (Cu-Zn) in the chelated. Reduction in the amount of available Cu was best described by the power function model (R2 = 0.91, SE = 0.081) in the non-chelated system and second order model (R2 = 0.95, SE = 0.010) in the chelated system. The applications generated from this study could be used as tools for improved micronutrient management and also provide baseline data for future work in other semi-arid/arid alkaline soils of the world. Findings are also more applicable to field settings, an improvement over related previous studies.

  14. Tumor targeting of radiolabeled antibodies using HYNIC chelate

    International Nuclear Information System (INIS)

    There is an increasing interest in the use of labeled antibodies for diagnosis of cancers as well as for therapy. Various radiolabeling methods have been used in order to obtain better tumor specific targeting for detection and therapy. It was generally used to tumor targeted immunotherapy and immunodetection that lym-1, mouse monoclonal antibody, was specific binding to surface antigen of Raji. The 3E8 antibody was produced from humanized anti-TAG-72 monoclonal antibody (AKA) by amino acid change in 95-99 residues of heavy chain complementary determinant regions (HCDRs) 3 using phage displayed library technology. In this study, we are investigating the usefulness of HYNIC chelate as a bifunctional chelating agent in radioimmunodetecton of tumor. Two types of antibodies, Lym-1 and 3E8, were used for the conjugation with HYNIC chelate. Lym-1 and 3E8 are specific antibodies to surface antigen of Non-Hogkin's lymphoma and TAG-72 antigen of colorectal carcinoma, respectively. We prepare HYNIC-antibody conjugates, determine radiolabeling yield with 99mTc and evaluate tumor targeting in tumor bearing nude mice model

  15. In vitro test system for evaluating the effectiveness of chelators

    International Nuclear Information System (INIS)

    A procedure has been devised to test in vitro the relative effectiveness of chelating agents for the elimination of radiotoxins from specified, in vivo labeled endogenous ligands. The report describes the elimination of 239Pu from liver homogenates by various chelating agents. The effectivity of a homologous series of polyaminocarboxylic acids (PACA's) was compared to that of certain derivatives containing a straight alkyl group. The effectiveness of these lipophilic PACA's appears to depend on the chain length of the substituent. Lipophilic chelons were more effective in chelating 239Pu than unsubstituted PACA's. Combination of EDTA or DTPA with a number of oligodentate complexing agents were also tested. With EDTA, the removal of Pu was enhanced by p-aminosalicylic acid (PAS), Desferioxamine B (DFOA) and strongly enhanced by 4,5-Dihydroxy-m-benzenedisulfonic acid (Tiron). Only DFOA showed enhanced removal with DTPA. The different behavior of the mixed ligand treatments can be explained by either formation of binary complexes or action on different biological Pu-pools

  16. Hydroxyurea could be a good clinically relevant iron chelator.

    Directory of Open Access Journals (Sweden)

    Khushnooma Italia

    Full Text Available Our previous study showed a reduction in serum ferritin of β-thalassemia patients on hydroxyurea therapy. Here we aimed to evaluate the efficacy of hydroxyurea alone and in combination with most widely used iron chelators like deferiprone and deferasirox for reducing iron from experimentally iron overloaded mice. 70 BALB/c mice received intraperitonial injections of iron-sucrose. The mice were then divided into 8 groups and were orally given hydroxyurea, deferiprone or deferasirox alone and their combinations for 4 months. CBC, serum-ferritin, TBARS, sTfr and hepcidin were evaluated before and after iron overload and subsequently after 4 months of drug therapy. All animals were then killed. Iron staining of the heart and liver tissue was done using Perl's Prussian Blue stain. Dry weight of iron in the heart and liver was determined by atomic absorption spectrometry. Increased serum-ferritin, TBARS, hepcidin and dry weight of iron in the liver and heart showed a significant reduction in groups treated with iron chelators with maximum reduction in the group treated with a combination of deferiprone, deferasirox and hydroxyurea. Thus hydroxyurea proves its role in reducing iron from iron overloaded mice. The iron chelating effect of these drugs can also be increased if given in combination.

  17. Separation of human IgG fragments using copper, nickel, zinc, and cobalt chelated to CM-Asp-agarose by positive and negative chromatography.

    Science.gov (United States)

    Mourão, Cecília Alves; Carmignotto, Gabriela Pannunzio; Bueno, Sonia Maria Alves

    2016-04-01

    This study evaluated the feasibility of using immobilized metal-ion affinity chromatography (IMAC) for separation of human Fab fragments using four different transition metal ions copper, nickel, zinc, and cobalt chelated to CM-Asp (carboxymethylaspartate) immobilized on the agarose gel. The Fab and Fc fragments (from human IgG digested with papain) interacted differently with the chelates studied, depending on the adsorption buffer system. The interaction between chelate and Fc fragment is predominantly based on the coordination bonds using adsorption buffer containing NaCl. Negative chromatography was performed on Cu(II)-CM-Asp-agarose obtaining 2.9mg of Fab per mL of adsorbent in nonretained fractions (Fc fragment-free without uncleaved IgG). The adsorption of Fab fragments is governed by electrostatic forces in the absence of NaCl in the adsorption buffer. High selectivity was achieved on Co(II)-CM-Asp-agarose and 5.7mg of Fab per mL of adsorbent was obtained in eluted fractions without Fc fragments, although having uncleaved IgG. The results showed that chromatography on transition metal ions chetated to CM-Asp-agarose is a promising approach to separation of Fab fragments from papain-digested human IgG solution. PMID:26974869

  18. Cathodic Tb(III) chelate electrochemiluminescence at oxide-covered magnesium and n-ZnO:Al/MgO composite electrodes

    International Nuclear Information System (INIS)

    Some of the luminescent aromatic Tb(III) chelates can be excited at oxide-covered magnesium and n-ZnO:Al/MgO composite electrodes by cathodic pulse polarization in aqueous solution. This is based on the cathodic injection of hot electrons into the aqueous electrolyte solution and successive redox reactions in one-electron steps resulting in the excited states of the chelates. Due to the relatively long luminescence lifetime of multidentate Tb(III) chelates, these chelates can be very sensitively detected by time-resolved electrochemiluminescence (TR-ECL) measurements using the present working electrodes. Thus, metal or highly doped semiconductor electrodes coated by a thin MgO film lend themselves as nontransparent or in some cases, even optically transparent working electrodes for generation of free radicals and cathodic ECL in aqueous solution. The results suggest that also other even more efficient optically transparent composite tunnel emission electrodes than the present n-ZnO:Al/MgO electrodes could be constructed by coating n-ZnO:Al glass electrodes with other wide band gap insulating oxides

  19. Determination of free Gd3+ as a cyclohexanediaminetetraacetic acid complex by reversed-phase HPLC in ionic gadolinium(III) chelates

    International Nuclear Information System (INIS)

    A reversed-phase HPLC method to analyze free Gd3+ in ionic Gd chelates, Gd(EDTA)-, Gd(DPTA)2-, and Gd(DOTA)-, was developed. In the method, free Gd3+ was complexed with cyclohexanediaminetetraacetic acid (CDTA). Either the complexation was carried out before analysis or CDTA was added to the buffered mobile phase (pH 7.4, Tris-HCI) to complex the free metal in the chelate sample. The complex Gd(CDTA)- was separated from the ionic chelate by high-performance liquid chromatography on a C18 reversed-phase Nucleosil column. A fluorescence detection method with 280-and 310-nm excitation and emission wavelengths, respectively, was used for monitoring. The recoverability, the linearity, and the limit of detection (LOD) of the method were determined. The method was evaluated in terms of thermodynamic and kinetic properties of Gd(CDTA)-, Gd(EDTA)-, Gd(DTPA)2-, and Gd(DOTA)-. The LOD for Gd3+ in the ionic chelates was 39 ng. 27 refs., 4 figs., 3 tabs

  20. Significance of 111In-DTPA chelate in renal radioactivity levels of 111In-DTPA-conjugated peptides

    International Nuclear Information System (INIS)

    Metabolic studies of 111In-DTPA-labeled polypeptides and peptides showed that the radiolabeled (poly)peptides generated 111In-DTPA-adducts of amino acid that possess long residence times in the lysosomal compartment of the tissues where (poly)peptides accumulated. However, a recent study suggested that metal-chelate-methionine (Met) might possess in vivo behaviors different from metal-chelate adducts of other amino acids. In this study, to elucidate whether some biological characteristics of Met may accelerate the renal elimination rate of 111In-DTPA-adduct of Met into urine, 111In-DTPA-Met1-octreotide was synthesized and the renal handling of 111In-DTPA-Met was investigated using 111In-DTPA-L-Phe1-octreotide (Phe represents phenylalanine), which was reported previously, as a reference. Both 111In-DTPA-conjugated octreotide analogs were stable against 3-h incubation in murine serum at 37 deg. C. Both 111In-DTPA-octreotide analogs also showed rapid clearance of the radioactivity from the blood and similar accumulation of the radioactivity in the kidney. No significant differences were observed in the renal radioactivity levels from 10 min to 24 h postinjection between the two. Metabolic studies indicated that 111In-DTPA-Met1-octreotide and 111In-DTPA-L-Phe1-octreotide generated 111In-DTPA-adducts of Met and Phe, respectively, as the final radiometabolites at similar rates. These findings suggested that the long residence times of the radioactivity in tissues after administration of 111In-DTPA-labeled peptides and polypeptides would be attributed to inherent characteristics of 111In-DTPA chelate

  1. Targeting Divalent Metal Ions at the Active Site of the HIV-1 RNase H Domain: NMR Studies on the Interactions of Divalent Metal Ions with RNase H and Its Inhibitors

    OpenAIRE

    Jiangli Yan; Haihong Wu; Tiffany Tom; Oleg Brodsky; Karen Maegley

    2011-01-01

    HIV-1 reverse transcriptase (RT) RNase H (HIV-RH) is a key target of anti-AIDS drugs. Metal-chelating compounds are an important class of chemicals in pharmacological drug discovery, especially in relation to HIV-RT and the highly-related HIV-integrase. The correlation between the metal-chelating properties and enzyme activities of the metal chelators is always of high scientific interest, as an understanding of this may accelerate the rational optimization of this class of inhibitors. Our NM...

  2. Neutralization of the haemorrhagic activities of viperine snake venoms and venom metalloproteinases using synthetic peptide inhibitors and chelators.

    Science.gov (United States)

    Howes, J-M; Theakston, R D G; Laing, G D

    2007-04-01

    Envenoming by the West African saw-scaled viper, Echis ocellatus resembles that of most vipers, in that it results in local blistering, necrosis and sometimes life-threatening systemic haemorrhage. While effective against systemic envenoming, current antivenoms have little or no effect against local tissue damage. The major mediators of local venom pathology are the zinc-dependant snake venom metalloproteinases (SVMPs). The high degree of structural and functional homology between SVMPs and their mammalian relatives the matrix metalloproteinases (MMPs) suggests that substrate/inhibitor interactions between these subfamilies are likely to be analogous. In this study, four recently developed MMP inhibitors (MMPIs) (Marimastat, AG-3340, CGS-270 23A and Bay-12 9566) are evaluated in addition to three metal ion chelators (EDTA, TPEN and BAPTA) for their ability to inhibit the haemorrhagic activities of the medically important E. ocellatus venom and one of its haemorrhagic SVMPs, EoVMP2. As expected, the metal ion chelators significantly inhibited the haemorrhagic activities of both whole E. ocellatus venom and EoVMP2, while the synthetic MMPIs show more variation in their efficacies. These variations suggest that individual MMPIs show specificity towards SVMPs and that their application to the neutralization of local haemorrhage may require a synthetic MMPI mixture, ensuring that a close structural component for each SVMP is represented. PMID:17196631

  3. The Alchemist’s Approach to Metal Poisoning: Transforming the Metal Burden

    Directory of Open Access Journals (Sweden)

    Wayne Briner

    2014-06-01

    Full Text Available Metal poisoning is a global problem with humans being exposed to a wide range of metals in varying doses and varying time frames. Traditionally, treatment involves removal of the toxic source or chelation therapy. An intermediate approach is needed. This review outlines the argument for the use of essential metal supplementation as a strategy to induce metallothionein expression and displace the toxic metal from important biological systems, improving the metal burden of the patient. Specific recommendations are given for supplementation with calcium, zinc and vitamin E as a broad strategy to improve the status of those exposed to toxic metals.

  4. In vivo stability and inertness of various direct labelled and chelate-tagged protein

    International Nuclear Information System (INIS)

    There were looking for methods giving precise information about composition and activity distribution of protein components, both in the initial samples and serum samples after intravenous administration. It was tested the applicability of electroimmunoassay, polyacrilamide gel electrophoresis and high performance liquid chromatography for the assessment of in vivo stability and labelled proteins. The model compound was human serum albumin (HSA) labelled with 99mTc and 125I, respectively. Bifunctional chelate labelling was done with desferrioxamine, in this case protein was labelled with 67Ga. Biodistribution of the labelled compounds and their elimination from the blood were studied in rabbits. Experience with various labelling proteins, especially with Tc-Sn-HSA system indicate that in vivo stability of this compounds are generally low. Following intravenous injection of proteins labelled with metal isotopes, due to dilution and to the presence of considerable amount of compatitive protein in the serum, part of the label is being detached from the carrier protein. Distribution of the detached metal is different from the original distribution of the protein. This problem arises also with radiopharmaceuticals based on monoclonal antibodies. (M.E.L.)

  5. Chelation of some transitions, lanthanides and uranium elements with nitrilotriacetic acid and radiolysis of their aqueous solutions

    International Nuclear Information System (INIS)

    The present thesis contains chelation studies of some transition metal ions (iron fe (III), cobalt Co (II) and nickel Ni (II), trivalent lanthanide ions (praseodymium pr(III) neodymium nd (III), samarium sm(III), europium Eu(III), gadolinium Gd (III), dysprosium dy (III), erbium Er(III) and ytterbium Yb(III) and uranium (U(IV) and U (V I)) with nitrilotriacetic acid (NTA). spectrophotometric techniques are used to investigate the effectiveness of NTA as a decontaminating agent for radioactive nuclides and to evaluate the optimum conditions under which stable and soluble complexes can be formed. these studies include the effect of PH on the formed complexes and determination of stability constants of the formed species. potentiometric analysis are also performed to follow the formation of binary complexes of some sulpha drugs with investigated metal ions and mixed ligand complexes arising to determine their formation constants

  6. Kinetic method for simultaneous determination of cadmium(II) and manganese(II) by ligand substitution reaction between 1-(2-pyridylazo)-2-naphthol chelates and EDTA

    International Nuclear Information System (INIS)

    Simultaneous kinetic determination of cadmium and manganese, on the basis on the difference of the rate of ligand substitution reaction between 1-(2-pyridylazo) -2-naphthol (PAN) chelate and EDTA in ammonia buffer solution, has been studied. Although the difference of the rate of the ligand substitution reaction between cadmium chelate and manganese chelate is small in the absence of ammonia, it becomes sufficiently large enough for simultaneous determination by an addition of ammonia because of an acceleration of the reaction of cadmium chelate caused by a catalytic effect of the ammonia. PAN and its chelates were solubilized in water with nonionic surfactant, Triton X-100, and with a small amount of methanol to measure the rate of the reaction by a stopped-flow technique. The procedures are as follows; Take a sample solution containing less than 28 μg of cadmium and 14 μg of manganese into 50 cm3 volumetric flask, add 10 mg of ascorbic acid and 5 cm3 of 4.0 x 10-3 mol dm-3 PAN solution (10% Triton X-100, 10% methanol), and adjust the pH of the solution to 8.8 with 10 cm3 of 2.0 mol dm-3 ammonia buffer and then dilute to the make with water. The reaction of this solution with 2.0 x 10-3 mol dm-3 EDTA solution (pH 8.8 with ammonia buffer) was observed by a stopped-flow apparatus at 250C. Change in the absorbance at 554 nm as a function of the reaction time was recorded and the concentration of cadmium and manganese were determined by linear extrapolation method from the reaction curves. The present method is free of interferences with other metal ions and anions, and applicable for the determination of cadmium and manganese in mining waste and treated water. (author)

  7. Brazilian Thalassemia Association protocol for iron chelation therapy in patients under regular transfusion

    OpenAIRE

    Monica Pinheiro de Almeida Verissimo; Sandra Regina Loggetto; Antonio Fabron Junior; Giorgio Roberto Baldanzi; Nelson Hamerschlak; Juliano de Lara Fernandes; Aderson da Silva Araujo; Clarisse Lopes de Castro Lobo; Kleber Yotsumoto Fertrin; Vasilios Antonios Berdoukas; Renzo Galanello

    2013-01-01

    In the absence of an iron chelating agent, patients with beta-thalassemia on regular transfusions present complications of transfusion-related iron overload. Without iron chelation therapy, heart disease is the major cause of death; however, hepatic and endocrine complications also occur. Currently there are three iron chelating agents available for continuous use in patients with thalassemia on regular transfusions (desferrioxamine, deferiprone, and deferasirox) providing good results in red...

  8. Alkenes as Chelating Groups in Diastereoselective Additions of Organometallics to Ketones

    OpenAIRE

    Raffier, Ludovic; Gutierrez, Osvaldo; Stanton, Gretchen R.; Kozlowski, Marisa C.; Walsh, Patrick J.

    2014-01-01

    Alkenes have been discovered to be chelating groups to Zn(II), enforcing highly stereoselective additions of organozincs to β,γ-unsaturated ketones. 1H NMR studies and DFT calculations provide support for this surprising chelation mode. The results expand the range of coordinating groups for chelation-controlled carbonyl additions from heteroatom Lewis bases to simple C–C double bonds, broadening the 60 year old paradigm.

  9. Red Blood Cell Transfusion Independence Following the Initiation of Iron Chelation Therapy in Myelodysplastic Syndrome

    OpenAIRE

    Leitch, Heather A.; Vickars, Linda M.; Chase, Jocelyn M.; Badawi, Maha A.

    2010-01-01

    Iron chelation therapy is often used to treat iron overload in patients requiring transfusion of red blood cells (RBC). A 76-year-old man with MDS type refractory cytopenia with multilineage dysplasia, intermediate-1 IPSS risk, was referred when he became transfusion dependent. He declined infusional chelation but subsequently accepted oral therapy. Following the initiation of chelation, RBC transfusion requirement ceased and he remained transfusion independent over 40 months later. Over the ...

  10. Korean Guideline for Iron Chelation Therapy in Transfusion-Induced Iron Overload

    OpenAIRE

    Jang, Jun Ho; Lee, Je-Hwan; Yoon, Sung-Soo; Jo, Deog-Yeon; Kim, Hyeoung-Joon; Chung, Jooseop; Lee, Jong Wook

    2013-01-01

    Many Korean patients with transfusion-induced iron overload experience serious clinical sequelae, including organ damage, and require lifelong chelation therapy. However, due to a lack of compliance and/or unavailability of an appropriate chelator, most patients have not been treated effectively. Deferasirox (DFX), a once-daily oral iron chelator for both adult and pediatric patients with transfusion-induced iron overload, is now available in Korea. The effectiveness of deferasirox in reducin...

  11. Chelation behaviour of lanthanons with o-arsonodibenzoylmethanephenlylhydrazone

    International Nuclear Information System (INIS)

    The chelate formation reaction of La(III), Pr(III), Nd(III), Gd(III), Ho(III), and Er(III) with o-arsonodibenzoylmethanephenylhydrazone has been investigated potentiometrically and conductometrically in 40 % (ν/ν) aqueous ethanol, ionic strength 0,1 M. The order of stability constants was found to be La Gd 3+: L). The complexes have been isolated in solid state and have been characterized on the basis of elemental analysis and IR data. Coordination occurs through - NH of the hydrazo and - OH of the arsonic groups. (Authors)

  12. Chelate-modified polymers for atmospheric gas chromatography

    Science.gov (United States)

    Christensen, W. W.; Mayer, L. A.; Woeller, F. H. (Inventor)

    1980-01-01

    Chromatographic materials were developed to serve as the stationary phase of columns used in the separation of atmospheric gases. These materials consist of a crosslinked porous polymer matrix, e.g., a divinylbenzene polymer, into which has been embedded an inorganic complexed ion such as N,N'-ethylene-bis-(acetylacetoniminato)-cobalt (2). Organic nitrogenous bases, such as pyridine, may be incorporated into the chelate polymer complexes to increase their chromatographic utility. With such materials, the process of gas chromatography is greatly simplified, especially in terms of time and quantity of material needed for a gas separation.

  13. IMMUNOASSAYS FOR METAL IONS. (R824029)

    Science.gov (United States)

    AbstractAntibodies that recognize chelated forms of metal ions have been used to construct immunoassays for Cd(II), Hg(II), Pb(II), and Ni(II). In this paper, the format of these immunoassays is described and the binding properties of three monoclonal antibodies direc...

  14. Effect of dietary trace mineral concentration and source (inorganic vs. chelated) on performance, mineral status, and fecal mineral excretion in pigs from weaning through finishing.

    Science.gov (United States)

    Creech, B L; Spears, J W; Flowers, W L; Hill, G M; Lloyd, K E; Armstrong, T A; Engle, T E

    2004-07-01

    Two hundred and sixteen weanling gilts (6.65+/-0.08 kg) were used to determine the effects of decreasing supplemental concentrations of Zn, Cu, Fe, and Mn, and trace mineral source (inorganic vs. chelated) on growth performance, mineral status, and fecal mineral concentrations from weaning through development. The study was conducted over three trials with 72 pigs in each trial. Gilts were blocked by weight and randomly assigned to either 1) control, 2) reduced inorganic, or 3) reduced chelated trace minerals. The control diet was supplemented with 25, 150, 180, and 60 mg/kg of Cu, Zn, Fe, and Mn (in sulfate forms), respectively, during the nursery phase and 15, 100, 100, and 40 mg/kg of supplemental Cu, Zn, Fe, and Mn, respectively, during the growing and gilt-developer phases. Reduced inorganic and reduced chelated treatments were supplemented during all phases with 5, 25, 25, and 10 mg/kg of Cu, Zn, Fe, and Mn, respectively. The reduced chelated treatment supplied 50% of the supplemental Cu, Zn, Fe, and Mn in the form of metal proteinates, with the remainder from sulfate forms. Performance by control pigs did not differ from pigs fed the reduced trace mineral treatments during the nursery and grower-development periods. Gain:feed was lower (P < 0.05) for pigs fed the reduced inorganic compared with those fed the reduced chelated treatment during the nursery period. Trace mineral source did not affect performance during the growing or gilt-developer phase. Plasma Zn concentration and alkaline phosphatase activity were higher (P < 0.01) in control pigs than in those receiving reduced trace minerals during the nursery and growing phases. Plasma Cu concentration and ceruloplasmin activity were generally not affected by treatment. Hemoglobin concentrations were lower (P < 0.05) for the reduced inorganic compared with the reduced chelated treatment in the nursery phase. Fecal concentrations of Cu, Zn, and Mn were lower (P < 0.05) in pigs fed reduced trace minerals

  15. The Mechanism of Sol-Gel Synthesis of Normal Spinel LiMn2O4 with Chelation of Citric Acid

    Institute of Scientific and Technical Information of China (English)

    WU Hui; LEI Jia-heng; CHEN Yong-xi; SUN Yu-bin; YUAN Qi-hua

    2002-01-01

    The sol-gel process of citric acid chelating with metal cations for the synthesis of normal spinel LiMn2O4 and the reaction mechanism were investigated by means of XRD, IR, TG-DTA, and SEM. The results show that at the beginning lithium citrate and chelate compound of citric acid with manganese ions formed, and then with heating the esterification and condensation reactions occured between them and glycol. The products obtained are polymers in which metal cations are distributed homogeneously on atomic scale that ensure high reactivity to cations of Li + and Mn2 + . Firing the gel prepared by this process, the lattice diffusions of solid reactant ions caused by non-homogeneity of reactants are eliminated and avoided. At 400℃ phase-pure LiMn2 O4 with nanometer scale crystallization having precise stoichiometry and perfect crystallization can be obtained. The model of chelate coordinate of double-molecule between citric acid and Mn2 + in the gel network is proposed. It is important for explaining the dispersion state of Mn2 + and the formation process of gel by this model.

  16. Detoxication and removal of uranium by phenolic chelating agents

    International Nuclear Information System (INIS)

    The use of phenolic chelating agents for detoxication and removal of uranyl nitrate in mice and rats is reported. Antidotal test: 8102, 7601 and 811 were given 2 mM/kg subcutaneously to mice and 1 mM/kg intramuscularly to rats when the animals were injected i.p. with different doses (100-500 mg/kg) of uranyl nitrate. The results showed that the antidotal effects of 8102 and 7601 were better than 811 in augmenting survival, survival time (day) and renal factor (kidney weight/body weight x100). 8102 was superior to 7601 against higher dose of uranyl nitrate intoxication. Removal test: five phenolic chelating agents (8102, 7601, 811, 7603 and 8307) were studied in rats. The results obtained demonstrated that 8102 and 7601 were better than 811, 7603 and 8307 in increasing U excretion in the urine after acute uranyl nitrate intoxication. The effects of different doses (300-1000 μM/kg) of 8102 was superior to 7601 in increasing U excretion in the urine and decreasing U deposition in the tissues. The toxicity and dose of 8102 in treating uranium intoxication are discussed

  17. Topical efficacy of dimercapto-chelating agents against lewisite-induced skin lesions in SKH-1 hairless mice

    Energy Technology Data Exchange (ETDEWEB)

    Mouret, Stéphane, E-mail: stephane.mouret@irba.fr [Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, Centre de Recherches du Service de Santé des Armées, 24 avenue Maquis du Grésivaudan, 38700 La Tronche (France); Wartelle, Julien; Emorine, Sandy; Bertoni, Marine; Nguon, Nina; Cléry-Barraud, Cécile [Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, Centre de Recherches du Service de Santé des Armées, 24 avenue Maquis du Grésivaudan, 38700 La Tronche (France); Dorandeu, Frédéric [Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, Centre de Recherches du Service de Santé des Armées, 24 avenue Maquis du Grésivaudan, 38700 La Tronche (France); Ecole du Val-de-Grâce, 1 place Alphonse Laveran, Paris (France); Boudry, Isabelle [Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, Centre de Recherches du Service de Santé des Armées, 24 avenue Maquis du Grésivaudan, 38700 La Tronche (France)

    2013-10-15

    Lewisite is a potent chemical warfare arsenical vesicant that can cause severe skin lesions. Today, lewisite exposure remains possible during demilitarization of old ammunitions and as a result of deliberate use. Although its cutaneous toxicity is not fully elucidated, a specific antidote exists, the British anti-lewisite (BAL, dimercaprol) but it is not without untoward effects. Analogs of BAL, less toxic, have been developed such as meso-2,3-dimercaptosuccinic acid (DMSA) and have been employed for the treatment of heavy metal poisoning. However, efficacy of DMSA against lewisite-induced skin lesions remains to be determined in comparison with BAL. We have thus evaluated in this study the therapeutic efficacy of BAL and DMSA in two administration modes against skin lesions induced by lewisite vapor on SKH-1 hairless mice. Our data demonstrate a strong protective efficacy of topical application of dimercapto-chelating agents in contrast to a subcutaneous administration 1 h after lewisite exposure, with attenuation of wound size, necrosis and impairment of skin barrier function. The histological evaluation also confirms the efficacy of topical application by showing that treatments were effective in reversing lewisite-induced neutrophil infiltration. This protective effect was associated with an epidermal hyperplasia. However, for all the parameters studied, BAL was more effective than DMSA in reducing lewisite-induced skin injury. Together, these findings support the use of a topical form of dimercaprol-chelating agent against lewisite-induced skin lesion within the first hour after exposure to increase the therapeutic management and that BAL, despite its side-effects, should not be abandoned. - Highlights: • Topically applied dimercapto-chelating agents reduce lewisite-induced skin damage. • One topical application of BAL or DMSA is sufficient to reverse lewisite effects. • Topical BAL is more effective than DMSA to counteract lewisite-induced skin damage.

  18. Topical efficacy of dimercapto-chelating agents against lewisite-induced skin lesions in SKH-1 hairless mice

    International Nuclear Information System (INIS)

    Lewisite is a potent chemical warfare arsenical vesicant that can cause severe skin lesions. Today, lewisite exposure remains possible during demilitarization of old ammunitions and as a result of deliberate use. Although its cutaneous toxicity is not fully elucidated, a specific antidote exists, the British anti-lewisite (BAL, dimercaprol) but it is not without untoward effects. Analogs of BAL, less toxic, have been developed such as meso-2,3-dimercaptosuccinic acid (DMSA) and have been employed for the treatment of heavy metal poisoning. However, efficacy of DMSA against lewisite-induced skin lesions remains to be determined in comparison with BAL. We have thus evaluated in this study the therapeutic efficacy of BAL and DMSA in two administration modes against skin lesions induced by lewisite vapor on SKH-1 hairless mice. Our data demonstrate a strong protective efficacy of topical application of dimercapto-chelating agents in contrast to a subcutaneous administration 1 h after lewisite exposure, with attenuation of wound size, necrosis and impairment of skin barrier function. The histological evaluation also confirms the efficacy of topical application by showing that treatments were effective in reversing lewisite-induced neutrophil infiltration. This protective effect was associated with an epidermal hyperplasia. However, for all the parameters studied, BAL was more effective than DMSA in reducing lewisite-induced skin injury. Together, these findings support the use of a topical form of dimercaprol-chelating agent against lewisite-induced skin lesion within the first hour after exposure to increase the therapeutic management and that BAL, despite its side-effects, should not be abandoned. - Highlights: • Topically applied dimercapto-chelating agents reduce lewisite-induced skin damage. • One topical application of BAL or DMSA is sufficient to reverse lewisite effects. • Topical BAL is more effective than DMSA to counteract lewisite-induced skin damage

  19. Extraction of metals and/or metalloids from acidic media using supercritical fluids and salts

    International Nuclear Information System (INIS)

    A method is described for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical carbon dioxide, containing a chelating agent. The chelating agent forms chelates that are soluble in the fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent comprises a trialkyl phosphate, a triaryl phosphate, a trialkylphosphine oxide, a triarylphosphine oxide, or mixtures thereof. The method provides an environmentally benign process for removing contaminants from industrial waste. The method is particularly useful for extracting actinides from acidic solutions, and the process can be aided by the addition of nitrate salts. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process. 7 figs

  20. SYNTHESES AND ADSORPTION PROPERTIES OF PHENOL-FORMALDEHYDE TYPE CHELATING RESINS BEARING THE FUNCTIONAL GROUP OF TARTARIC ACID

    Institute of Scientific and Technical Information of China (English)

    Rong-jun Qu; Chun-nuan Ji; Yan-zhi Sun; Zhong-fang Li; Guo-xiang Cheng; Ren-feng Song

    2004-01-01

    Several kinds of novel chelating resins bearing the functional group of tartaric acid (TTA-FQ-12, TTA-FQ-23, and TTA-FQ-34) were synthesized by reacting epoxy maleic anhydride, which was prepared through the oxidization reaction of maleic anhydride by hydrogen peroxide, with phenol-formaldehyde resin containing polyamine (FQ resins series). The effects of such factors as reaction time, reaction temperature and pH value on the loading capacity of TTA in resins were investigated. The results showed that the optimum reaction conditions are as follows: time 9-12 h; temperature 90-105℃;pH value 6-10. The loading capacities of TTA can reach 0.15, 0.14, and 0.11 mmol/g-1 when the functional group of FQ resin was -OCH2CH2NHC2H4NH2, -O(CH2CH2NH)2C2H4NH2 and -O(CH2CH2NH)3C2H4NH2), respectively. The structures of resins were characterized by FTIR spectra. The primary study on the adsorption properties of the resins for metal ions showed that there are two kinds of adsorption mechanisms i.e. ion exchange and chelate in the adsorption process.TTA-FQ resins have much higher adsorption selectivity for Pb2+and Zn2+ than for Cu2+ and Ni2+. These resins can probably be used for separating Pb2+ or Zn2+ in the mixture of metal ions or for treating wastewater containing heavy metal ions.

  1. Influence of chelation therapy (DTPA) on 141Ce retention in rats

    International Nuclear Information System (INIS)

    We investigated the influence of oral and parenteral administration of chelation therapy on the retention of 141Ce in young rats. Opposite to results obtained in adult rats present results show high efficacy of oral chelation therapy in reducing radiocerium retention in the whole body and organs of suckling rats. (author) 3 refs

  2. A novel BF2-chelated azadipyrromethene-fullerene dyad: synthesis, electrochemistry and photodynamics.

    Science.gov (United States)

    Amin, Anu N; El-Khouly, Mohamed E; Subbaiyan, Navaneetha K; Zandler, Melvin E; Fukuzumi, Shunichi; D'Souza, Francis

    2012-01-01

    The synthesis, structure, electrochemistry and photodynamics of a BF(2)-chelated azadipyrromethene-fullerene dyad are reported in comparison with BF(2)-chelated azadipyrromethene without fullerene. The attachment of fullerene resulted in efficient generation of the triplet excited state of the azadipyrromethene via photoinduced electron transfer. PMID:22083226

  3. Effects of chelating agents on protein, oil, fatty acid amd seed mineral concentrations in soybean

    Science.gov (United States)

    Soybean seed is a major source of protein and oil for human diet. Since not much information is available on the effects of chelating agents on soybean seed composition constituents, the current study aimed to investigate the effects of various chelating agents on soybean [(Glycine max (L.) Merr.)] ...

  4. Inhibitor Ranking Through QM based Chelation Calculations for Virtual Screening of HIV-1 RNase H inhibition

    DEFF Research Database (Denmark)

    Poongavanam, Vasanthanathan; Svendsen, Casper Steinmann; Kongsted, Jacob

    2014-01-01

    of the methods based on the use of a training set of molecules, QM based chelation calculations were used as filter in virtual screening of compounds in the ZINC database. By this, we find, compared to regular docking, QM based chelation calculations to significantly reduce the large number of false...

  5. The application of chelating resin to the elimination of interferences in the analysis of trace hazardous elements

    International Nuclear Information System (INIS)

    In general, digestion with nitric and sulfuric acids are applied in the analysis of trace elements in solid materials like industrial products and soils. This causes the digested solution to contain high concentrations of sulfate ion. In addition, silicate, chloride and other interferences, which are contained in the material itself, can also be included. These interfering matrices are separated generally through solvent extraction. In stead of the solvent extraction method, we applied the solid phase extraction method using chelating resin, which has a functional group of iminodiacetic acid, for the analysis of trace hazardous metals such as Cd and Pb in industrial products, soils, and other materials containing high concentrations of matrix components. In the presence of high concentrations of interfering ions, over 80% of Cd and Pb and Pb were extracted, with one exception that the recovery of Cd from seawater decreased to 60-30% in the presence of 19g/L of chloride ion. On the other hand, Cr, As and Se were extracted at a low recovery rate with this type of chelating resin. (author)

  6. Transport investigations of terbium chelate complexes in a type 1 collagen tissue model using quantitative micro-endoscopic imaging

    Science.gov (United States)

    Houlne, Michael P.; Goebel, Timothy S.; Bornhop, Darryl J.

    1999-06-01

    The diffusive transport characteristics of a unique class of small fluorescent molecular probes in an interstitial tissue model are investigated using micro-endoscopy. The probes employed in the present work are organo-metallic complexes of polyazamacrocycles chelated to Terbium. These particular molecules have large Stoke's shifts, making them amendable to tissue analysis. The delocalized electronic structure of the organic chelate absorbs ultra-violate light (approximately 270 nm) and, after inter-molecular transfer, the lanthanide cation fluoresces in the visible region (550 nm). The diffusive transport properties of the probe molecules are related to their chemical structure, which governs their affinity toward the components of the interstitial model. The basic polyazamacrocycle is functionalized with three phosphate groups. Presently, methyl, ethyl, propyl and butyl alkyl chains are added to the phosphate groups on the polyazamacrocycle to modify the affinity of the probes toward the components of the interstitial model. Micro-endoscopy coupled with digital imaging allows remote, quantitative analysis of the transport process in near real time. Cross sectional analysis of the images yields the concentration profile of the probe as it diffuses through the gel. The concentration profile is fit to Fick's second law of diffusion to determine the diffusion coefficient, D, for each of the problem molecules. Presently the measured D values for each of the compounds are typical for small molecules in water (approximately 10-6 cm2/sec), however, D is observed to increase with decreasing hydrocarbon chain length which demonstrates interstitial transport is structurally dependent.

  7. Red Blood Cell Transfusion Independence Following the Initiation of Iron Chelation Therapy in Myelodysplastic Syndrome

    Directory of Open Access Journals (Sweden)

    Maha A. Badawi

    2010-01-01

    Full Text Available Iron chelation therapy is often used to treat iron overload in patients requiring transfusion of red blood cells (RBC. A 76-year-old man with MDS type refractory cytopenia with multilineage dysplasia, intermediate-1 IPSS risk, was referred when he became transfusion dependent. He declined infusional chelation but subsequently accepted oral therapy. Following the initiation of chelation, RBC transfusion requirement ceased and he remained transfusion independent over 40 months later. Over the same time course, ferritin levels decreased but did not normalize. There have been eighteen other MDS patients reported showing improvement in hemoglobin level with iron chelation; nine became transfusion independent, nine had decreased transfusion requirements, and some showed improved trilineage myelopoiesis. The clinical features of these patients are summarized and possible mechanisms for such an effect of iron chelation on cytopenias are discussed.

  8. Brazilian Thalassemia Association protocol for iron chelation therapy in patients under regular transfusion

    Directory of Open Access Journals (Sweden)

    Monica Pinheiro de Almeida Verissimo

    2013-01-01

    Full Text Available In the absence of an iron chelating agent, patients with beta-thalassemia on regular transfusions present complications of transfusion-related iron overload. Without iron chelation therapy, heart disease is the major cause of death; however, hepatic and endocrine complications also occur. Currently there are three iron chelating agents available for continuous use in patients with thalassemia on regular transfusions (desferrioxamine, deferiprone, and deferasirox providing good results in reducing cardiac, hepatic and endocrine toxicity. These practice guidelines, prepared by the Scientific Committee of Associação Brasileira de Thalassemia (ABRASTA, presents a review of the literature regarding iron overload assessment (by imaging and laboratory exams and the role of T2* magnetic resonance imaging (MRI to control iron overload and iron chelation therapy, with evidence-based recommendations for each clinical situation. Based on this review, the authors propose an iron chelation protocol for patients with thalassemia under regular transfusions.

  9. Immune responses in lactating Holstein cows supplemented with Cu, Mn, and Zn as sulfates or methionine hydroxy analogue chelates.

    Science.gov (United States)

    Nemec, L M; Richards, J D; Atwell, C A; Diaz, D E; Zanton, G I; Gressley, T F

    2012-08-01

    The aim of this study was to compare effects of inorganic sulfate versus chelated forms of supplemental Cu, Mn, and Zn on milk production, plasma and milk mineral concentrations, neutrophil activity, and antibody titer response to a model vaccination. Holstein cows (n=25) were assigned in 2 cohorts based on calving date to a 12-wk randomized complete block design study. The first cohort consisted of 17 cows that had greater days in milk (DIM; mean of 77 DIM at the start of the trial) than the second cohort of 8 cows (32 DIM at the start of the trial). Diets were formulated to supplement 100% of National Research Council requirements of Cu, Mn, and Zn by either inorganic trace minerals (ITM) in sulfate forms or chelated trace minerals (CTM) supplied as metal methionine hydroxy analog chelates, without accounting for trace mineral contribution from other dietary ingredients. Intake and milk production were recorded daily. Milk composition was measured weekly, and milk Cu, Mn, and Zn were determined at wk 0 and 8. Plasma Cu and Zn concentrations and neutrophil activity were measured at wk 0, 4, 8, and 12. Neutrophil activity was measured by in vitro assays of chemotaxis, phagocytosis, and reactive oxygen species production. A rabies vaccination was administered at wk 8, and vaccine titer response at wk 12 was measured by both rapid fluorescent focus inhibition test and ELISA. Analyzed dietary Cu was 21 and 23mg/kg, Mn was 42 and 46mg/kg, and Zn was 73 and 94mg/kg for the ITM and CTM diets, respectively. No effect of treatment was observed on milk production, milk composition, or plasma minerals. Dry matter intake was reduced for CTM compared with ITM cows, but this was largely explained by differences in body weight between treatments. Milk Cu concentration was greater for CTM than ITM cows, but this effect was limited to the earlier DIM cohort of cows and was most pronounced for multiparous compared with primiparous cows. Measures of neutrophil function were

  10. Synthesis and antimalarial activity of metal complexes of cross-bridged tetraazamacrocyclic ligands

    OpenAIRE

    Timothy J. Hubin; Amoyaw, Prince N. -A.; Roewe, Kimberly D.; Simpson, Natalie C.; Maples, Randall D.; Carder Freeman, TaRynn N.; Amy N. Cain; Le, Justin G.; Stephen J Archibald; Khan, Shabana I.; Tekwani, Babu L.; Khan, M. O. Faruk

    2014-01-01

    Using transition metals such as manganese(II), iron(II), cobalt(II), nickel(II), copper(II), and zinc(II), several new metal complexes of cross-bridged tetraazamacrocyclic chelators namely, cyclen- and cyclam-analogs with benzyl groups, were synthesized and screened for in vitro antimalarial activity against chloroquine-resistant (W2) and chloroquine-sensitive (D6) strains of Plasmodium falciparum. The metal-free chelators tested showed little or no antimalarial activity. All the metal comple...

  11. Incorporation of 241Am: effectiveness of late DTPA chelation therapy

    International Nuclear Information System (INIS)

    In four persons who had incorporated 241Am probably by inhalation, a DTPA chelation therapy was initiated several months after incorporation. Excretion measurements and in vivo measurements were performed in order to quantify the enhancement of 241Am excretion and the activity distribution in the body. DTPA was administered 4-11 times as an infusion of 1 g DTPA. Daily excretion rates were raised essentially, up to factors of 65-140 (urine) and 30-50 (faeces) after the first administration. Dose calculations performed on the basis of a modified ICRP 30, Part 4 model yielded dose reductions (e.g. for subject A) of 90%, 28%, 28% and 26% for liver, bone surfaces, red bone marrow and lungs, respectively, corresponding to a reduction of the effective dose equivalent of approximately 40%. (author)

  12. Economically dissolving barium sulfate scale with a chelating agent

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, E.A.; Scheuerman, R.E.

    1977-06-21

    A composition is described for dissolving a barium sulfate scale from a subterranean or other relatively remote location into which fluid can be flowed. Fluid is flow-flowed into the remote location so that a stream of fluid contacts and flows along the surface of the scale. The composition and flow rate of the fluid are adjusted so that (1) the scale is contacted by a stream of aqueous solution in which each portion contains enough dissolved aminopolyacetic acid salt chelating agent to dissolve barium sulfate, and (2) substantially all upstream portions of the scale are contacted by a succession of portions of the aqueous liquid which are substantially unsaturated with respect to dissolved barium-chelant complex. (5 claims)

  13. Effects of Zinc Chelators on Aflatoxin Production in Aspergillus parasiticus

    Science.gov (United States)

    Wee, Josephine; Day, Devin M.; Linz, John E.

    2016-01-01

    Zinc concentrations strongly influence aflatoxin accumulation in laboratory media and in food and feed crops. The presence of zinc stimulates aflatoxin production, and the absence of zinc impedes toxin production. Initial studies that suggested a link between zinc and aflatoxin biosynthesis were presented in the 1970s. In the present study, we utilized two zinc chelators, N,N,N′,N′-tetrakis (2-pyridylmethyl) ethane-1,2-diamine (TPEN) and 2,3-dimercapto-1-propanesulfonic acid (DMPS) to explore the effect of zinc limitation on aflatoxin synthesis in Aspergillus parasiticus. TPEN but not DMPS decreased aflatoxin biosynthesis up to six-fold depending on whether A. parasiticus was grown on rich or minimal medium. Although we observed significant inhibition of aflatoxin production by TPEN, no detectable changes were observed in expression levels of the aflatoxin pathway gene ver-1 and the zinc binuclear cluster transcription factor, AflR. Treatment of growing A. parasiticus solid culture with a fluorescent zinc probe demonstrated an increase in intracellular zinc levels assessed by increases in fluorescent intensity of cultures treated with TPEN compared to controls. These data suggest that TPEN binds to cytoplasmic zinc therefore limiting fungal access to zinc. To investigate the efficacy of TPEN on food and feed crops, we found that TPEN effectively decreases aflatoxin accumulation on peanut medium but not in a sunflower seeds-derived medium. From an application perspective, these data provide the basis for biological differences that exist in the efficacy of different zinc chelators in various food and feed crops frequently contaminated by aflatoxin. PMID:27271668

  14. Effects of Zinc Chelators on Aflatoxin Production in Aspergillus parasiticus.

    Science.gov (United States)

    Wee, Josephine; Day, Devin M; Linz, John E

    2016-01-01

    Zinc concentrations strongly influence aflatoxin accumulation in laboratory media and in food and feed crops. The presence of zinc stimulates aflatoxin production, and the absence of zinc impedes toxin production. Initial studies that suggested a link between zinc and aflatoxin biosynthesis were presented in the 1970s. In the present study, we utilized two zinc chelators, N,N,N',N'-tetrakis (2-pyridylmethyl) ethane-1,2-diamine (TPEN) and 2,3-dimercapto-1-propanesulfonic acid (DMPS) to explore the effect of zinc limitation on aflatoxin synthesis in Aspergillus parasiticus. TPEN but not DMPS decreased aflatoxin biosynthesis up to six-fold depending on whether A. parasiticus was grown on rich or minimal medium. Although we observed significant inhibition of aflatoxin production by TPEN, no detectable changes were observed in expression levels of the aflatoxin pathway gene ver-1 and the zinc binuclear cluster transcription factor, AflR. Treatment of growing A. parasiticus solid culture with a fluorescent zinc probe demonstrated an increase in intracellular zinc levels assessed by increases in fluorescent intensity of cultures treated with TPEN compared to controls. These data suggest that TPEN binds to cytoplasmic zinc therefore limiting fungal access to zinc. To investigate the efficacy of TPEN on food and feed crops, we found that TPEN effectively decreases aflatoxin accumulation on peanut medium but not in a sunflower seeds-derived medium. From an application perspective, these data provide the basis for biological differences that exist in the efficacy of different zinc chelators in various food and feed crops frequently contaminated by aflatoxin. PMID:27271668

  15. Removal of iron by chelation with molecularly imprinted supermacroporous cryogel.

    Science.gov (United States)

    Çimen, Duygu; Göktürk, Ilgım; Yılmaz, Fatma

    2016-06-01

    Iron chelation therapy can be used for the selective removal of Fe(3+) ions from spiked human plasma by ion imprinting. N-Methacryloyl-(L)-glutamic acid (MAGA) was chosen as the chelating monomer. In the first step, MAGA was complexed with the Fe(3+) ions to prepare the precomplex, and then the ion-imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-glutamic acid) [PHEMAGA-Fe(3+)] cryogel column was prepared by cryo-polymerization under a semi-frozen temperature of - 12°C for 24 h. Subsequently, the template, of Fe(3+) ions was removed from the matrix by using 0.1 M EDTA solution. The values for the specific surface area of the imprinted PHEMAGA-Fe(3+) and non-imprinted PHEMAGA cryogel were 45.74 and 7.52 m(2)/g respectively, with a pore size in the range of 50-200 μm in diameter. The maximum Fe(3+) adsorption capacity was 19.8 μmol Fe(3+)/g cryogel from aqueous solutions and 12.28 μmol Fe(3+)/g cryogel from spiked human plasma. The relative selectivity coefficients of ion-imprinted cryogel for Fe(3+)/Ni(2+) and Fe(3+)/Cd(2+) were 1.6 and 4.2-fold greater than the non-imprinted matrix, respectively. It means that the PHEMAGA-Fe(3+) cryogel possesses high selectivity to Fe(3+) ions, and could be used many times without significantly decreasing the adsorption capacity. PMID:25727711

  16. Beneficial effect of sesame oil on heavy metal toxicity.

    Science.gov (United States)

    Chandrasekaran, Victor Raj Mohan; Hsu, Dur-Zong; Liu, Ming-Yie

    2014-02-01

    Heavy metals become toxic when they are not metabolized by the body and accumulate in the soft tissue. Chelation therapy is mainly for the management of heavy metal-induced toxicity; however, it usually causes adverse effects or completely blocks the vital function of the particular metal chelated. Much attention has been paid to the development of chelating agents from natural sources to counteract lead- and iron-induced hepatic and renal damage. Sesame oil (a natural edible oil) and sesamol (an active antioxidant) are potently beneficial for treating lead- and iron-induced hepatic and renal toxicity and have no adverse effects. Sesame oil and sesamol significantly inhibit iron-induced lipid peroxidation by inhibiting the xanthine oxidase, nitric oxide, superoxide anion, and hydroxyl radical generation. In addition, sesame oil is a potent inhibitor of proinflammatory mediators, and it attenuates lead-induced hepatic damage by inhibiting nitric oxide, tumor necrosis factor-α, and interleukin-1β levels. Because metal chelating therapy is associated with adverse effects, treating heavy metal toxicity in addition with sesame oil and sesamol may be better alternatives. This review deals with the possible use and beneficial effects of sesame oil and sesamol during heavy metal toxicity treatment. PMID:23744838

  17. Adsorptive stripping voltammetric measurements of trace levels of uranium following chelation with Mordant Blue 9

    International Nuclear Information System (INIS)

    The chelate of uranium with the azo dye Mordant Blue 9 is shown to be adsorbed and then reduced on the hanging mercury drop electrode. These properties have been exploited in developing a highly sensitive stripping voltammetric procedure for trace determination of uranium. With controlled adsorptive accumulation for 5 min, a detection limit near 2 x 10-10 M uranium is obtained. Cyclic voltammetry has been used to characterize the interfacial and redox behaviour. The effect of various operational parameters on the stripping response is discussed. Experimental conditions include use of 1 x 10-6 M Mordant Blue 9 in 0.05 M acetate buffer (pH 6.5), an accumulation potential of -0.43 V, and a linear potential scan. The response is linear up to 1.2 x 10-7 M uranium, and the relative standard deviation at 4.2 x 10-8 M is 3.2%. The effects of possible interferences from organic surfactants or metal ions have been investigated. (author)

  18. Analysis of the brain tissues from a patient with Alzheimer's disease and effects of chelating treatment

    International Nuclear Information System (INIS)

    Alzheimer's, Parkinson's disease and ALS are among major neurodegenerative diseases. The cause of neurodegeneration is unknown, but there are indications that excessive accumulation of essential elements, and sometimes, incorporation of toxic foreign elements in neurons aggravate neurodegeneration. During the past decade, many researchers investigated the causative factors in degenerative diseases to specify genetic or environmental factor. PIXE analysis has been used for these studies because of the sample preparation is easy and detection limit is very low. However, the concentration of matrix elements and foreign elements are extremely low and difficult to detect and to quantify. In this study, specimens from patients with Alzheimer's disease with no chemical treatment, and those with chelating were analyzed. In all analyzed specimens, Na, Al, Si, P, S, Cl, Ca, Ti, Vi, Cr, Fe and Cu were detected. Each specimen in this study consisted of cerebral cortex and substantia alba. From these experiments we can observe a clear tendency that the accumulation of the metal elements use different depending on the constituent tissues, and the method of sample preparation has a dominant role in the measurement results. (author)

  19. Chelating, antioxidant and hypoglycaemic potential of Muscari comosum (L.) Mill. bulb extracts.

    Science.gov (United States)

    Loizzo, Monica R; Tundis, Rosa; Menichini, Federica; Pugliese, Alessandro; Bonesi, Marco; Solimene, Umberto; Menichini, Francesco

    2010-12-01

    The metal chelating activity, antioxidant properties and the effect on carbohydrate-hydrolysing enzyme inhibition of Muscari comosum extracts have been investigated. M. comosum bulbs contain a total amount of the phenols with a value of 56.6 mg chlorogenic acid equivalent per gram of extract and a flavonoid content of 23.4 mg quercetin equivalent per gram of extract. In order to evaluate the non-polar constituents, n-hexane extract was obtained. Gas chromatography-mass spectrometry analysis revealed the presence of fatty acids and ethyl esters as major constituents, with different aldehydes and alkanes as minor components. Ethanolic extract had the highest ferric-reducing ability power (66.7 μM Fe(II)/g) and DPPH scavenging activity with a concentration giving 50% inhibition (IC₅₀) value of 40.9 μg/ml. Moreover, this extract exhibited a good hypoglycaemic activity with IC₅₀ values of 81.3 and 112.8 μg/ml for α-amylase and α-glucosidase, respectively. In conclusion, M. comosum bulbs show promising antioxidant and hypoglycaemic activity via the inhibition of carbohydrate digestive enzymes. These activities may be of interest from a functional point of view and for the revalorization of this ancient non-cultivated vegetable of Mediterranean traditional gastronomy. PMID:20465433

  20. Chelate titrations of Ca(2+) and Mg(2+) using microfluidic paper-based analytical devices.

    Science.gov (United States)

    Karita, Shingo; Kaneta, Takashi

    2016-06-14

    We developed microfluidic paper-based analytical devices (μPADs) for the chelate titrations of Ca(2+) and Mg(2+) in natural water. The μPAD consisted of ten reaction zones and ten detection zones connected through narrow channels to a sample zone located at the center. Buffer solutions with a pH of 10 or 13 were applied to all surfaces of the channels and zones. Different amounts of ethylenediaminetetraacetic acid (EDTA) were added to the reaction zones and a consistent amount of a metal indicator (Eriochrome Black T or Calcon) was added to the detection zones. The total concentrations of Ca(2+) and Mg(2+) (total hardness) in the water were measured using a μPAD containing a buffer solution with a pH of 10, whereas only Ca(2+) was titrated using a μPAD prepared with a potassium hydroxide solution with a pH of 13. The μPADs permitted the determination of Ca(2+) and Mg(2+) in mineral water, river water, and seawater samples within only a few minutes using only the naked eye-no need of instruments. PMID:27181645