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PubMed2006

Development of a health-protective drinking water level for perchlorate.

We evaluated animal and human toxicity data for perchlorate and identified reduction of thyroidal iodide uptake as the critical end point in the development of a health-protective drinking water level [also known as the public health goal (PHG)] for the chemical. This work was performed under the drinking water program of the Office of Environmental Health Hazard Assessment of the California Environmental Protection Agency. For dose-response characterization, we applied benchmark-dose modeling to human data and determined a point of departure (the 95% lower confidence limit for 5% inhibition of iodide uptake) of 0.0037 mg/kg/day. A PHG of 6 ppb was calculated by using an uncertainty factor of 10, a relative source contribution of 60%, and exposure assumptions specific to pregnant women. The California Department of Health Services will use the PHG, together with other considerations such as economic impact and engineering feasibility, to develop a California maximum contaminant level for perchlorate. We consider the PHG to be adequately protective of sensitive subpopulations, including pregnant women, their fetuses, infants, and people with hypothyroidism.

Animals↗
PubMedDate not supplied

Effect of perchlorate ion within the polypyrrole matrix on the electrooxidation of ethylene glycol in acidic media.

The electrooxidation of ethylene glycol was investigated on platinum and perchlorate ions doped polypyroole film electrodes in acidic media. The presence of perchlorate ion was observed by XPS experiments. Optimum experimental conditions were determined. The electrooxidation kinetic of ethylene glycol was studied as a function of ethylene glycol concentration, potential scan limit and scan rate. Results suggest that the doping process has a strong effect on the oxidation reaction.

Electrochemistry↗
PubMed2004

[Investigation of bromate, haloacetic acids and perchlorate in Beijing's drinking water].

Disinfection by-products and perchlorate in the raw water and finished water of Beijing's a drinking water plants were investigated. The results indicated that there was little bromate in the drinking water. Five haloacetic acids (HAAs) were found in the water. The concentrations of the sum of the five HAAs were ranged from 42.1 micrograms/L to 149.5 micrograms/L. In the HAAs, the chlorine-containing HAAs accounted for more than 90% of the total HAAs. In the five HAAs, the concentration order of the HAAs were trichloroacetic acid > dichloroacetic acid > bromochloroacetic acid > dibromoacetic acid > bromodichloroacetic acid. The HAAs in Beijing's drinking water were much influenced by the variation of season. They had the highest concentrations in September and lowest concentration in April, respectively. For perchlorate in Beijing's drinking water, it was greatly influenced by the groundwater. Its concentrations were between 0.1-6.8 micrograms/L in the finished drinking water. It had peak value in November and minimum value in July, respectively.

Acetates↗
PubMed2004

Hydrogen-based, hollow-fiber membrane biofilm reactor for reduction of perchlorate and other oxidized contaminants.

Many oxidized pollutants, such as nitrate, perchlorate, bromate, and chlorinated solvents, can be microbially reduced to less toxic or less soluble forms. For drinking water treatment, an electron donor must be added. Hydrogen is an ideal electron donor, as it is non-toxic, inexpensive, and sparsely soluble. We tested a hydrogen-based, hollow-fiber membrane biofilm reactor (MBfR) for reduction of perchlorate, bromate, chlorate, chlorite, chromate, selenate, selenite, and dichloromethane. The influent included 5 mg/L nitrate or 8 mg/L oxygen as a primary electron accepting substrate, plus 1 mg/L of the contaminant. The mixed-culture reactor was operated at a pH of 7 and with a 25 minute hydraulic detention time. High recirculation rates provided completely mixed conditions. The objective was to screen for the reduction of each contaminant. The tests were short-term, without allowing time for the reactor to adapt to the contaminants. Nitrate and oxygen were reduced by over 99 percent for all tests. Removals for the contaminants ranged from a minimum of 29% for chlorate to over 95% for bromate. Results show that the tested contaminants can be removed as secondary substrates in an MBfR, and that the MBfR may be suitable for treating these and other oxidized contaminants in drinking water.

Biofilms↗
PubMed1975

Rat mammary gland atypia produced by iodine blockade with perchlorate.

Prior published work from our laboratory concluded that there was a need for appropriate metabolic activity of iodine in breast tissue for normal growth and development. Results from studies in rats that were made iodine deficient showed histological changes in the breasts that were atypical and dysplastic. These tissue findings were further affected by the presence of estrogen and thyroxine. These changes parallel the iodine uptake of the tissues, thus representing a difference in the utilization of iodine by the mammary glands. Using an ion blockade agent, sodium perchlorate, breast tissues lacking iodine were evaluated by both endocrine and histological techniques. A dose-response series was completed that showed that perchlorate therapy for 8 weeks at 400 mg/100 ml produced breast blockade by a reduction in iodine uptake of greater than 52% of the control. At these levels, the histological experimentation showed atypia and some pleomorphism of the cells, particularly in the glands of the lobules. Blockade was less effective in estrogen-treated groups. It is especially notable that both histological changes and uptake reduction were greatest in those breasts that had been rendered euthyroid by thyroxine replacement, thus clearly indicating the necessity of iodine itself for maintenance of normal breast development. By this blockade the responses of iodine inadequacy in the breast were shown to cause abnormal tissue changes relative to the percentage of the block obtained.

Animals↗
PubMed1977

Rectal perchlorate for unconscious patients prior to brain scintigraphy with pertechnetate: concise communication.

Patients undergoing brain scintigraphy with pertechnetate are frequently premedicated with oral perchlorate. However, the oral route is difficult to employ in unconscious or uncooperative patients or when oral intake is restricted. In such situations, rectal administration of sodium perchlorate dissolved in water is an effective alternative to oral administration.

Brain Diseases↗
PubMed1986

31P nuclear magnetic resonance analysis of lung cancer: the perchloric acid extract spectrum.

31P-NMR spectra were obtained from the perchloric acid extracts of normal lung and lung cancer tissues obtained at surgery, and from extracts of neoplastic cells cultured in vitro. The perchloric acid extract of lung cancer tissue gave rise to a signal whose chemical shift was 3.2 ppm at pH 8.0. This signal was not observed in the extract of normal tissue of the lung from the same patient. The compound giving this signal was identified as phosphorylcholine.

Adenoviridae↗
PubMed1982

Perchloric acid-soluble serum glycoprotein as an index for tumor cell burden in the early detection of cancer.

Neoplastic cells, particularly human mammary carcinoma cells, shed or secrete glycoproteins which are tumor-specific. These compounds contain N-acetylneuraminic acid (NANA) and they differ from the bulk of serum proteins and glycoproteins in being soluble in perchloric acid. Graded number of R3230 adenocarcinoma (AdCa) cells were implanted subcutaneously in groups of female Fisher rats. At time intervals, while under anesthesia the spleens were dissected out, and blood was drawn from the animals. The blood was examined for NANA levels and the spleen cells for lymphocyte migration inhibition. The serum perchloric acid (PA) soluble proteins and the PA-NANA levels were time-dependent and increased with the number of implanted tumor cells. Maximum levels were found in sera from blood drawn 196 hours or later from animals which received 1,000 tumor cells/rat, or more. At 72 hours or more after tumor cell implantation, migration of splenic lymphocytes from animals which received 100 or more R3230 AdCa cells per animal was inhibited on contact with neuraminidase-treated formalinized R3230 AdCa cells. The magnitude of inhibition increased with time and with the number of implanted tumor cells. Therefore, blood PA-NANA levels and lymphocyte migration inhibition rae parameters for the in-vivo early detection and monitor tumor cell proliferation.

Adenocarcinoma↗
PubMed1997

Effect of sodium chloride, chlorite, and perchlorate on the hypochlorite-induced peroxidation of phospholipid liposomes.

The abilities of sodium hypochlorite (NaClO), chlorite (NaClO2), chlorate (NaClO3), and perchlorate (NaClO4) to initiate lipid peroxidation (LP) in liposomes formed from unsaturated phosphatidylcholine were compared. It was shown that only NaClO induced an intensive accumulation of LP products (thiobarbituric acid-reactive substances and diene conjugates) in the liposomes as a result of their co-incubation. The other oxochlorates produced no similar effects and did not affect the hypochlorite-induced LP. This indicates that the observed hypochlorite-induced LP does not result from the presence of chlorite, chlorate, or perchlorate anion admixtures in the medium.

Animals↗
PubMed1997

[Treatment of amiodarone-induced hyperthyroidism: corticosteroids or potassium perchlorate? What value do interleukin-6 levels have?].

We report 11 cases of amiodarone-induced hyperthyroidism. We tried to classify them into 2 groups, according to Bartelena et al. (JCEM 81: 2930, 1996). The serum level of interleukin-6 (IL-6) was measured in 7 patients by an immunoenzymometric assay. In type I (cases 1-3) the thyroid was abnormal (goiter, Graves' disease) but IL-6 levels were normal. These cases were successfully managed by the combined use of thionamide drugs (carbimazol or propylthioruacil = PTU) and potassium perchlorate. In type II (case 4), the thyroid seemed to be normal but the serum level of IL-6 was increased, possibly due to a destructive thyroiditis. Treatment with prednisone (40 mg/day) and PTU resulted in a prompt normalization of T3. Contrary to Bartalena et al., we observed cases with normal thyroid and normal levels of IL-6 (cases 5-8) (type III). In these cases prednisone (40 mg/day for 2 weeks) was ineffective but the combined use of thionamide drugs and perchlorate was associated with a normalization of thyroid hormones. This combined treatment seems to be effective in most patients (type I, III). In case of failure of this treatment, a high dose of prednisone (1 mg/kg) could be tried or a lower dosage (40 mg/day) could be used in cases with high IL-6 levels (type II).

Adult↗
PubMed1998

[123I-scintigraphy and perchlorate depletion test in the diagnosis of congenital hypothyroidism].

AIM: Thirty eight children suffering from congenital primary permanent hypothyroidism were studied to determine the diagnostic impact of 123I scintigraphy in comparison to laboratory findings and ultrasonography. METHODS: In all patients 123I scintigraphy was performed after intravenous administration of 3.7 MBq 123I. If accumulation of the radiotracer in thyroid tissue occurred a perchlorate discharge test was performed subsequently. RESULTS: Scintigraphy revealed athyrosis in 7 children. In 9 children a lingual thyroid was observed. Deficiency in iodine organification was diagnosed by a significant discharge of 123I in 15 patients. In four of these children the diagnosis of Pendred's syndrome could be established. Ectopic thyroid tissue could be demonstrated only by scintigraphy where clinical examination and sonography failed in the diagnosis in all cases. Hypoplasia of the thyroid gland as it was diagnosed in 2 cases by ultrasonography appeared to be unlikely because a normal 123I uptake was seen in these patients. In 2 patients with scintigraphic proven athyrosis an orthotopic gland had been falsely considered by ultrasound. In 44% of our patients the final diagnosis could only be established if 123I scintigraphy and perchlorate discharge test were performed. CONCLUSION: This findings suggest that scintigraphy is indispensible in the correct diagnostic work up of congenital hypothyroidism.

Child↗
PubMed1998

Influence of Nitrate and Perchlorate Anions on the Kinetics of the Goethite Formation.

The synthesis of goethite by oxidation of ferrous iron solutions in the presence of metallic iron has been carried out at temperatures ranging from 20 to 70 degreesC and initial pH form 1 to 4; air flow rate is kept constant at 1 L/min. The influence of nitrate and perchlorate anions has been studied for salt concentrations ranging from 0 to 1 mol/L. The rates of iron oxidation and goethite precipitation are significantly enhanced. As expected, the nitrate anion presents many more marked oxidative properties than perchlorate. Domains of precipitation of goethite have been determined and presented in diagrams based on the factors cited above. In the presence of nitrate, magnetite precipitates in large domains corresponding to an increase in either temperature or pH. Ferrous iron concentrations are very low during magnetite precipitation, below 2 x 10(-3) g/L. They remain constant during the precipitation of goethite, in the range 12-18 x 10(-3) g/L. Copyright 1998 Academic Press.

Journal Article↗
PubMed1984

NMR study of in vivo RIF-1 tumors. Analysis of perchloric acid extracts and identification of 1H, 31P and 13C resonances.

Perchloric acid extracts of radiation-induced fibrosarcoma (RIF-1) tumors grown in mice have been analyzed by multinuclear NMR spectroscopy and by various chromatographic methods. This analysis has permitted the unambiguous assignment of the 31P resonances observed in vivo to specific phosphorus-containing metabolites. The region of the in vivo spectra generally assigned to sugar phosphates has been found in RIF-1 tumors to contain primarily phosphorylethanolamine and phosphorylcholine rather than glycolytic intermediates. Phosphocreatine was observed in extracts of these tumor cells grown in culture as well as in the in vivo spectra, indicating that at least some of the phosphocreatine observed in vivo arises from the tumor itself and not from normal tissues. In the 31P-NMR spectra of the perchloric acid extract, resonances originating from purine and pyrimidine nucleoside di- and triphosphate were resolved. HPLC analyses of the nucleotide pool indicate that adenine derivatives were the most abundant components, but other nucleotides were present in significant amounts. The 1H and 13C resonance assignments of the majority of metabolites present in RIF-1 extracts have also been made. Of particular importance is the ability to observe lactate, the levels of which may provide a noninvasive measure of glycolysis in these cells in both the in vitro states. In addition, the aminosulfonic acid, taurine, was found in high levels in the tumor extracts.

Animals↗
PubMed2001

Hydrogen bonding in the crystal structure of bis[3-([thiomethyl]methyl)pyrazole]copper(II) perchlorate.

The ability of a metal-coordinated pyrazole to engage in hydrogen bonding has been explored by synthesis of the title complex, bis[3-([thiomethyl]methyl)pyrazole]copper(II) perchlorate (3). The coordination in 3 can be described as pseudo-octahedral, with two relatively tightly-bound 3-[(thiomethyl)methyl]pyrazole ligands occupying the equatorial plane, forming a [CuN(2)S(2)](2+) unit with the S donors mutually trans to each other. The axial positions are each filled by a weakly bound perchlorate counterion, one oxygen of which forms a hydrogen bond with the pyrazole N-H moiety on an adjacent [CuN(2)S(2)](2+) unit.

Journal Article↗
PubMed2003

Purification and characterization of perchloric acid soluble protein from rat lung.

We isolated a perchloric acid soluble protein from the post-mitochondria supernatant fraction of the rat lung and designated it as RLu-PSP1. The protein is soluble in 5% perchloric acid and was purified by ammonium sulfate fractionation and CM-Sephadex chromatography. The amino acid sequence of RLu-PSP was identical with that of rat liver PSP (RL-PSP). RLu-PSP inhibited protein synthesis in a rabbit reticulocyte lysate system. It was expressed mainly in cytoplasm of bronchioles and alveolar epithelial cells of the lung from 60-day-old rats. In 15-day-old rat embryos, the epithelial-lining of the terminal buds of the respiratory tree was immunopositive. The expression of RLu-PSP increased from the embryonic 15th day to the postnatal 40th day. This is the first report on the presence of a PSP in rat lung and on its involvement in the regulation of cellular growth and differentiation.

Amino Acid Sequence↗
PubMed2000

Coordination of lanthanide triflates and perchlorates with N,N,N',N'-tetramethylsuccinamide.

Compounds formed from the reaction of N,N,N',N'-tetramethylsuccinamide (TMSA) with trivalent lanthanide salts possessing the poorly coordinating counteranions triflate (CF3SO3-) and perchlorate (ClO4-) have been prepared and examined. Structural features of these Ln-TMSA compounds have been studied in the solid phase by thermogravimetric analysis, infrared spectroscopy, and, in selected cases, by single-crystal X-ray diffraction and in solution by infrared spectroscopy. Eight-coordinate compounds, [Ln(TMSA)4]3+, derived from coordination of four succinamide ligands to the metal ion could be formed with all lanthanides examined (Ln = La, Pr, Nd, Eu, Yb, Lu). Structural analyses by single-crystal X-ray diffraction were performed for the lanthanide triflate salts Ln(C8H16N2O2)4(CF3SO3)3: Ln = La, compound 1, monoclinic, P2(1)/n, a = 11.0952(2) A, b = 19.2672(2) A, c = 24.9759(3) A, beta = 90.637(1) degrees, Z = 4, Dcalcd = 1.586 g cm-3; Ln = Nd, compound 2, monoclinic, C2/c, a = 24.6586(10) A, b = 19.3078(7) A, c = 11.1429(4) A, beta = 90.450(1) degrees, Z = 4, Dcalcd = 1.603 g cm-3; Ln = Eu, compound 3, monoclinic, C2/c, a = 24.4934(2) A, b = 19.3702(1) A, c = 11.1542(1) A, beta = 90.229(1) degrees, Z = 4, Dcalcd = 1.617 g cm-3; Ln = Lu, compound 5, monoclinic, C2/c, a = 24.2435(4) A, b = 19.6141(2) A, c = 11.2635(1) A, beta = 90.049(1) degrees, Z = 4, Dcalcd = 1.626 g cm-3. X-ray analysis was also carried out for the perchlorate salt: Ln = Eu, compound 4, triclinic, P1, a = 10.9611(2) A, b = 14.6144(3) A, c = 15.7992(2) A, alpha = 106.594(1) degrees, beta = 91.538(1) degrees, gamma = 90.311(1) degrees, Z = 2, Dcalcd = 1.561 g cm-3. In the presence of significant amounts of water, 7-coordinate compounds with mixed aquo-TMSA cation structures [Ln(TMSA)3(H2O)]3+ (Ln = Yb) and [Ln(TMSA)2(H2O)3]3+ (Ln = La, Pr, Nd, Eu, Yb) have been isolated with structural determinations by single-crystal X-ray diffraction obtained for the following species: Yb(C8H16N2O2)3(H2O)(CF3SO3)3, compound 6, monoclinic, P2(1)/n, a = 8.9443(3) A, b = 11.1924(4) A, c = 44.2517(13) A, beta = 93.264(1) degrees, Z = 4, Dcalcd = 1.735 g cm-3; Yb(C8H16N2O2)3(H2O)(ClO4)3, compound 7, monoclinic, Cc, a = 19.2312(6) A, b = 11.1552(3) A, c = 19.8016(4) A, beta = 111.4260(1) degrees, Z = 4, Dcalcd = 1.690 g cm-3; Yb(C8H16N2O2)2(H2O)3(CF3SO3)3, compound 8, triclinic, P1, a = 8.6719(1) A, b = 12.2683(2) A, c = 19.8094(3) A, alpha = 75.815(1) degrees, beta = 86.805(1) degrees, gamma = 72.607(1) degrees, Z = 2, Dcalcd = 1.736 g cm-3. Unlike in the analogous nitrate salts, only bidentate binding of the succinamide ligand to the lanthanide metal is observed. IR spectroscopy studies in anhydrous acetonitrile suggest that the solid-state structures of these Ln-TMSA compounds are maintained in solution.

Journal Article↗
PubMed2005

Catalysis by methyltrioxorhenium(VII): reduction of hydronium ions by europium(II) and reduction of perchlorate ions by europium(II) and chromium(II).

The title reactions occur stepwise, the first and fastest being MeReO3 + Eu2+ --> Re(VI) + Eu3+ (k298 = 2.7 x 10(4) L mol(-1) s(-1)), followed by rapid reduction of Re(VI) by Eu2+ to MeReO2. The latter species is reduced by a third Eu2+ to Re(IV), a metastable species characterized by an intense charge transfer band, epsilon410 = 910 L mol(-1) cm(-1) at pH 1; the rate constant for its formation is 61.3 L mol(-1) s(-1), independent of [H+]. Yet another reduction step occurs, during which hydrogen is evolved at a rate v = k[Re(IV)][Eu2+][H+](-1), with k = 2.56 s(-1) at mu = 0.33 mol L(-1). The 410 nm Re(IV) species bears no ionic charge on the basis of the kinetic salt effect. We attribute hydrogen evolution to a reaction between H-ReVO and H3O+, where the hydrido complex arises from the unimolecular rearrangement of Re(III)-OH in a reaction that cannot be detected directly. Chromium(II) ions do not evolve H2, despite E(Cr) degrees approximately E(EU) degrees. We attribute this lack of reactivity to the Re(IV) intermediate being captured as [Re(IV)-O-Cr(III)]2+, with both metals having substitutionally inert d3 electronic configurations. Hydrogen evolution occurs in chloride or triflate media; with perchlorate present, MeReO2 reduces perchlorate to chloride, as reported previously [Abu-Omar, M. M.; Espenson, J. H. Inorg. Chem. 1995, 34, 6239-6240].

Journal Article↗
PubMed2006

Kinetics of the reaction of chromium(VI) with tris(1,10-phenanthroline)iron(II) ions in acidic solutions. Anion and medium effects: perchlorate versus triflate.

Reinvestigation of the reaction between title reagents in aqueous acidic triflate and perchlorate media revealed an unusual difference: the reaction is strictly first-order with respect to the concentration of Fe(phen)3(2+) (phen = 1,10-phenanthroline) in the triflate medium but shows an additional, but we believe artifactual, higher-order term in the perchlorate medium. We postulate that the apparent orders with respect to [Fe(phen)3(2+)] in (H/Li)ClO4 do not indicate the actual chemical mechanism but, in whole or in part, the orders, particularly the higher-order component, reflect an interaction specific to Fe(phen)3(2+) or Fe(phen)3(3+) and ClO4(-) in solution. Data in (H/Li)O3SCF3 solutions indicate that, in the absence of added Fe(phen)3(3+), the first of the three sequential electron-transfer steps is rate controlling. Reactions started in the presence of the product Fe(phen)3(3+) occur somewhat more slowly, suggesting the first electron transfer is reversible. This finding allows the relative rate constants for Cr(V) oxidation and reduction to be evaluated, with limited precision, by two methods of analysis. The dependences on [Cr(VI)] can be resolved into contributions from the species HCrO4(-) and Cr2O7(2-), each of which in turn depends on [H+]. The reaction mechanism is discussed in light of the data obtained in the triflate medium. Further, the rate constants for certain steps can be considered in light of E0 for the Cr(VI)/(V) couple.

Journal Article↗