Concentration Of Sodium Perchlorate Research Articles

The effects of sodium perchlorate on the liver of Molly Fish (Poecilia sphenops, Cyprinidae, Teleostei)

Adult male molly fishes were reared up to ten days in control water or in water containing sodium perchlorate at concentrations of 1, 5, 25 and 125 ppm. Remarkable steatosis, fibrosis, hyperemia and necrosis were distinguished in parallel with increasing sodium perchlorate concentrations. The striking cellular damages were observed especially in 25 and 125 ppm sodium perchlorate exposed animals. The exposition to 25 ppm sodium perchlorate induced hepatocellular breakdowns and nuclear polymorphism. In 125 ppm sodium perchlorate exposed fish, hyperemia and widened necrotic areas were discovered. The results were evaluated as being the first documentation of histopathological effects of sodium perchlorate on teleost liver.

Thyroidal angiogenesis in zebrafish (Danio rerio) exposed to high perchlorate concentration

As a well known environmental contaminant, perchlorate inhibits thyroidal iodide uptake and reduces thyroid hormone levels. In zebrafish (Danio rerio) exposed to high concentrations of sodium perchlorate (200, 350 and 500 mg/L) for 10 days, remarkable angiogenesis was identified, not only histopathologically but also statistically by counting of the small, medium and large sized (grades 1 to 3) vessels per unit area. Angiogenic response is concluded as the most sensitive parameter for rating of high concentrations of perchlorate exposure. Key words: Perchlorate, zebrafish, thyroid, angiogenesis.

The kinetics of reduction of palladium (II) complexes with β-alanine at dropping mercury electrode and the complexes’ stability constants

By using dc and ac polarography, the kinetics of electroreduction of the palladium (II) complexes with β-alanine at a dropping mercury electrode was studied in solutions with the palladium (II) concentration from 2 × 10−5 to 2 × 10−4 M and variable β-alanine and sodium perchlorate concentrations (pH 6–12). One polarographic wave was observed in solutions with pH 9 and 10 at the β-alanine overall concentration of cβala = 1 × 10−3 to 5 × 10−2 M; two waves, at lower pH or higher cβala. It was concluded on the formation of different forms of palladium (II) complexes in the studied solutions; the complexes contained two to four β-alanine coordinated anions. Using the limiting diffusion currents for the two waves at pH 9–11 and cβala = 0.1 and 0.5 M, the stepwise stability constant for the Pd(βala)42− complex was calculated. Using two ac peaks observed at pH 7–8 and cβala = 1 × 10−2 to 0.1 M, the stepwise stability constant for the Pd(βala)3−. was calculated. The perchlorate ions adsorbed at the dropping mercury electrode, as well as βala− anions at their higher concentrations, hamper the electroreduction of the palladium (II) complexes with β-alanine.

Thyroidal angiogenesis in zebrafish ( Danio rerio ) exposed to high perchlorate concentration

As a well known environmental contaminant, perchlorate inhibits thyroidal iodide uptake and reduces thyroid hormone levels. In zebrafish (Danio rerio) exposed to high concentrations of sodium perchlorate (200, 350 and 500 mg/L) for 10 days, remarkable angiogenesis was identified, not only histopathologically but also statistically by counting of the small, medium and large sized (grades 1 to 3) vessels per unit area. Angiogenic response is concluded as the most sensitive parameter for rating of high concentrations of perchlorate exposure.

The effects of sodium perchlorate on the liver of Molly Fish (Poecilia sphenops, Cyprinidae, Teleostei)

Adult male molly fishes were reared up to ten days in control water or in water containing sodium perchlorate at concentrations of 1, 5, 25 and 125 ppm. Remarkable steatosis, fibrosis, hyperemia and necrosis were distinguished in parallel with increasing sodium perchlorate concentrations. The striking cellular damages were observed especially in 25 and 125 ppm sodium perchlorate exposed animals. The exposition to 25 ppm sodium perchlorate induced hepatocellular breakdowns and nuclear polymorphism. In 125 ppm sodium perchlorate exposed fish, hyperemia and widened necrotic areas were discovered. The results were evaluated as being the first documentation of histopathological effects of sodium perchlorate on teleost liver.

Analyzing of high-density lipoprotein subfractions and low-density lipoprotein subfractions in human serum with anion-exchange chromatography

Objective We previously established a separation method for five lipoprotein classes (HDL, LDL, IDL, VLDL and chylomicrons) in human serum by using anion-exchange high-performance liquid chromatography (AEX-HPLC). It was thought that analyzing of the subfractions of HDL or LDL is important for study of the atherogenic lipoproteins in atherosclerotic diseases, because a large number of studies were reported regarding them. Therefore, we estimated a separation mode of AEX-HPLC for analyzing cholesterol levels of two HDL-subfractions and two LDL-subfractions. Methods In this method, the lipoproteins were separated by a step gradient of sodium perchlorate concentration, and the separated lipoproteins were detected by using a post-column reactor with a reagent containing cholesterol esterase and cholesterol oxidase. Results The major component of earlier-eluting fraction in HDL (HDL-f) and later-eluting fraction in HDL (HDL-s) were HDL3 and HDL2, respectively. The retention time of peak of earlier-eluting fraction in LDL (LDL-f) was changed into that of later-eluting fraction in LDL (LDL-s) by the oxidization, incubating 2 μmol/l copper ion in PBS for 3 h at 37 °C. The within- and between-day assay coefficients of variation (CV) for cholesterol levels of the lipoprotein subfractions were in the ranges of 0.85–19.23% and 2.55–23.50%, respectively. The cholesterol levels of HDL-f and HDL-s were lower in patients with coronary heart disease (CHD) than in healthy controls, while LDL-s cholesterol levels were higher in CAD patients than in healthy controls. Conclusions This accurate and convenient assay of the lipoprotein subfractions may be useful for studying the atherogenic lipoproteins.

Oligoribonucleotide Analogues Containing a Mixed Backbone of Phosphodiester and Formacetal Internucleoside Linkages, Together with Vicinal 2′‐O‐Methyl Groups

Oligoribonucleotides containing formacetal internucleoside linkages have been prepared and studied by UV melting experiments. In RNA duplexes, the formacetal substitution is stabilizing (Deltat(m)=0 to +0.9 degrees C per modification) at physiological salt concentrations (0.1 M) but destabilizing (Deltat(m)=-0.4 to -0.8 degrees C per modification) at high salt concentrations (1 M); this suggests that reduction of electrostatic repulsion contributes substantially to the stabilization. The presence of 2'-O-Me substituents increases the stabilities of the duplexes (Deltat(m)=+0.5 to +1.1 degrees C per modification). The positive effects of formacetals and 2'-O-Me groups were independent and additive. (1)H NMR studies on monomeric model compounds containing 3'-(ethyl phosphate) or 3'-O-ethoxymethyl groups showed that the formacetal and 2'-O-Me substitutions shift the conformational equilibria of the ribose residues towards the North conformers by 5 to 12 %. Although the preference for the North conformers qualitatively correlates with increased duplex stabilities, changes in thermodynamic parameters (DeltaH degrees and TDeltaS degrees ) for formation of oligonucleotide duplexes and differences in dependence on concentrations of sodium acetate, sodium chloride and sodium perchlorate suggest that solvation effects are also important for the duplex stabilities. Overall the formacetal linkages fit well in A-type RNA duplexes, making them potentially interesting modifications for RNA-based gene-control strategies (e.g., antisense and RNA interference).

Uptake, accumulation and depuration of sodium perchlorate and sodium arsenate in zebrafish (Danio rerio)

In toxicokinetics studies, interactions between chemicals in mixtures has been largely neglected. This study examines a mixture of perchlorate and arsenate because (1) they have the potential to co-occur in contaminated aquatic habitats, and (2) a previous study by the authors found possible toxicological interactive effects. In the present study, zebrafish (Danio rerio) were exposed to two concentrations of sodium perchlorate (10 and 100mgl−1), sodium arsenate (1 and 10mgl−1), and the mixture-sodium perchlorate+sodium arsenate (10+1mgl−1 and 100+10mgl−1 Na2HAsO4-high mixture) for 90d. Their uptake and accumulation by zebrafish was evaluated at 10, 30, 60, and 90d. In addition, depuration was examined at 1, 3, and 5d after cessation of the exposure. The uptake of either chemical was concentration-dependent, with significantly higher uptake at high concentrations at either exposure interval. In contrast, there was no significant difference in whole body residue between single chemicals and the corresponding mixture except for 100mgl−1 sodium arsenate at 90d. However, there was increasing accumulation over time at the high concentration of either chemical alone and their mixture, and this increasing trend was more pronounced in the single chemical exposures than in the mixture. At the concentrations tested in the current study, both chemicals reduced the uptake but enhanced the depuration of the other chemical from the zebrafish. This study represents the first examination of the interaction of two anions-perchlorate and arsenate with respect to toxicokinetics.

Contribution of ammonium ions to the lethality and antimetamorphic effects of ammonium perchlorate

Ammonium perchlorate (AP) is a widespread military waste product in the United States and is a potent thyroid function disruptor in all vertebrates tested thus far. To determine the relative contribution of ammonium ions to the toxicity of AP, we exposed embryonic and larval Xenopus laevis to various concentrations of sodium perchlorate (SP) or ammonium chloride (AC). Ammonium perchlorate was significantly more lethal than SP; 5-d LC50s were 83 and 2,780 mg/L, respectively. To determine whether ammonium ions contribute to the antithyroid effects of AP, we exposed embryonic and larval X. laevis to two sublethal, environmentally relevant concentrations of AP or identical concentrations of AC or SP. At the smaller concentration, only AP delayed metamorphosis and reduced hindlimb growth. Sodium perchlorate and AP, but not AC, prevented metamorphosis and reduced hindlimb growth at the greater concentration. Although AP was slightly more effective in reducing outward manifestations of thyroid disruption, both perchlorate salts, unlike AC, caused profound histopathologic changes in the thyroid. Exposure to the higher concentration of either perchlorate salt produced a feminizing effect, resulting in a skewed sex ratio. We conclude that ammonium ions contribute significantly to the toxicity of AP but not to the direct antithyroid effects of perchlorate.

Perchlorate Affects Thyroid Function in Eastern Mosquitofish (Gambusia holbrooki) at Environmentally Relevant Concentrations

The purpose of this study was to determine the effects of perchlorate on thyroid function in mosquitofish. Adult mosquitofish were exposed to 0, 0.1, 1, 10, 100, and 1000 mg/L sodium perchlorate for 2, 10, and 30 d. Whole body thyroxin (T4) content and histological assessment of thyroid follicles (e.g., follicular epithelial height, hyperplasia, hypertrophy, and colloid depletion) were used to gauge alterations in thyroid function. Follicular epithelial cell height, hyperplasia, and hypertrophy increased with increasing perchlorate concentration, especially in fish exposed for 30 d, and these effects were statistically significantly different from control at concentrations as low as 0.1 mg/L (nominal concentration). The percent occurrence of follicles with depleted colloid decreased with increasing perchlorate concentration, which is contrary to what is expected with thyroid inhibition. There also was a decrease in whole body T4 concentration in fish exposed to perchlorate for 30 d, but clear dose-response relationships were less evident for whole body T4 than for histopathological endpoints. In conclusion, thyroid histopathology provides a sensitive biomarker for thyroid endocrine disruption at environmentally relevant concentrations of sodium perchlorate, and whole body T4 is a less sensitive indicator of perchlorate exposure than is histopathology.

Joint toxicity of sodium arsenate and sodium perchlorate to zebrafish Danio rerio larvae

Joint toxicity of arsenate and perchlorate was tested in larvae of Danio rerio. Results indicated that the 96-h median lethal concentrations of sodium arsenate and sodium perchlorate were 258.8 and 1,401.2 mg/L, respectively, and that arsenate and perchlorate generally showed a concentration-additive effect.

Exposure to Perchlorate Induces the Formation of Macrophage Aggregates in the Trunk Kidney of Zebrafish and Mosquitofish

AbstractEnvironmental contamination of ground and surface waters by perchlorate, derived from ammonium perchlorate (AP) and other perchlorate salts, is of increasing concern. Exposure to perchlorate can impair the thyroid endocrine system, which is thought to modulate renal and immune function in vertebrates. This study with zebrafish Danio rerio and eastern mosquitofish Gambusia holbrooki examined the histological effects of perchlorate on the trunk kidney, which in teleosts serves excretory and hemopoietic functions and therefore may be a target of perchlorate effects. Adult zebrafish of both sexes were exposed in the laboratory to waterborne, AP‐derived perchlorate at measured concentrations of 18 mg/L for 8 weeks. Adult male mosquitofish were exposed to waterborne sodium perchlorate at measured perchlorate concentrations of 1–92 mg/L for 8 weeks. Control fish were kept in untreated water. The region of the body cavity containing the trunk kidney was processed from each fish for histological analysis. Macrophage aggregates (MAs), possible markers of contaminant exposure or immunotoxic effect, were present in the hemopoietic region of the kidney in both species exposed to perchlorate. The estimated percent area of kidney sections occupied by MAs was greater in zebrafish exposed to perchlorate at 18 mg/L (P < 0.05) than in controls. In male mosquitofish, the incidence of renal MAs increased proportionally with sodium perchlorate concentration and was significantly different from that of controls at 92 mg/L (P < 0.05). These observations confirm that in fish the kidney is affected by exposure to perchlorate. The concentrations of perchlorate at which the effects were noted are relatively high but within the range reported in some contaminated habitats.

Effects of solvent composition and ionic strength on the interaction of quinoline antimalarials with ferriprotoporphyrin IX

Enthalpy–entropy compensation in the interaction of quinoline antimalarials with ferriprotoporphyrin IX (Fe(III)PPIX) in 40% aqueous dimethyl sulfoxide (DMSO) has been compared with that in pure aqueous solution. The data indicate that the degree of desolvation and loss of conformational freedom is virtually identical in both systems. Taken together with previous findings showing that the molar free energies of association of these drugs with Fe(III)PPIX in both solvent systems are very similar, this suggests that the recognition site on the metalloporphyrin is comparable in both cases. This is despite the fact that Fe(III)PPIX exists as a dimer in aqueous solution, but is monomeric in 40% DMSO. Free energies of association of chloroquine, quinine and quinidine with Fe(III)PPIX are largely insensitive to the concentration of sodium perchlorate in 40% DMSO. This demonstrates that electrostatic interactions play only a minor role in the overall stability of these complexes under these conditions. Increasing DMSO concentration greatly weakens the interactions of chloroquine, amodiaquine, quinine, quinidine and 9-epiquinine with Fe(III)PPIX. This suggests that hydrophobic interaction plays a major role in the stability of these complexes. Further investigation of chloroquine has revealed that the free energy of association with Fe(III)PPIX also weakens as a function of decreasing solvent polarity in pure organic solvents. However, the free energies of association are weaker in the mixed aqueous solvent than in pure organic solvents. This indicates that dispersion and electrostatic interactions are relatively strong in the non-aqueous environment. The results demonstrate that any successful model of antimalarial drug–Fe(III)PPIX interactions will need to take both solvation and electrostatic factors into account.

Measurement of cholesterol of major serum lipoprotein classes by anion-exchange HPLC with perchlorate ion-containing eluent

We have developed a high-performance liquid chromatography (HPLC) method for measurement of cholesterol in the major classes of serum lipoproteins, i.e., HDL, LDL, IDL, VLDL, and chylomicrons. Lipoproteins in serum were separated on a column containing diethylaminoethyl-ligand nonporous polymer-based gel by elution with a step gradient of sodium perchlorate concentration, and detected by post-column reaction with a reagent containing cholesterol esterase and cholesterol oxidase. The within-day assay and between-day assay coefficients of variation for cholesterol concentration in lipoproteins were in the ranges of 0.9-6.4% and 1.1-11.9%, respectively. The correlation coefficients between the values of HDL, LDL, IDL, VLDL, and chylomicron cholesterol measured by the HPLC method and those estimated by an ultracentrifugation method were 0.892, 0.921, 0.840, 0.930, and 0.873, respectively. Values of remnant-like particle cholesterol measured by an immunoseparation technique (Japan Immunoresearch Laboratories, Japan) were significantly correlated with VLDL and chylomicron cholesterol values measured by the HPLC method (r = 0.883 and r = 0.729, respectively). This rapid and accurate HPLC method was successfully applied to the analysis of plasma lipoproteins of patients with hyperlipidemia.

Study of tryptophan enantiomer binding to a teicoplanin-based stationary phase using the perturbation technique: Investigation of the role of sodium perchlorate in solute retention and enantioselectivity

The retention of d, l-tryptophan enantiomers on an immobilized teicoplanin column was investigated in relation to the mobile phase sodium perchlorate concentration using the perturbation method to determine the solute distribution isotherms. From the experimental data, it appeared that the bi-Langmuir model was able to describe d- and l-enantiomer retention on the immobilized selector over the salt concentration range. An increase in the apparent enantioselectivity with an increase in sodium perchlorate concentration was observed. The chiral recognition enhancement was governed by (i) an increase in the difference of the adsorption constants for binding to the high-affinity site (aglycone pocket) between the two enantiomers and (ii) enhancement of the number of aglycone chiral regions interacting with d-tryptophan. It is suggested that an ion-pair formation mechanism between perchlorate and solute and/or selector is responsible for this behavior. In addition, this work shows that additional secondary sites on the teicoplanin surface are involved in the apparent enantioselectivity at low sodium perchlorate concentrations.

The pyrophosphate-assisted reduction of chromium(vi) by manganese(ii) and its reverse reactionElectronic supplementary information (ESI) available: derivation of the theoretical rate laws, apparent kinetic orders of Mn(ii) at various initial concentrations of Cr(vi) and at various temperatures, initial rates at various concentrations of sodium perchlorate, parameters a and b at various temperatures, and initial rates at various temperatures. See http://www.rsc.org/suppdata/nj/b1/b104573n/

We report the discovery of a novel reaction that behaves in an unexpected way. Although Cr(VI) and Mn(II) do not react in the absence of stabilizing ligands, they react in aqueous perchloric acid provided that pyrophosphate [a stabilizing ligand for Mn(III)] is present in the medium. The reaction [whose stoichiometry is Cr(VI) + 3 Mn(II) → Cr(III) + 3 Mn(III)] takes place in a reversible manner, but the kinetic plots are not as those expected for conventional reversible reactions. On the contrary, a period of decay of the Cr(VI) concentration [and formation of Mn(III)] is followed by a period in which that reactant is actually regenerated (and the product consumed). During the course of the reaction, pyrophosphate is slowly hydrolyzed to phosphate. This hydrolysis constitutes the driving force for the backward reaction. A mechanism involving three consecutive 1-electron redox steps is proposed for the reduction of Cr(VI) to Cr(III), in each step a Mn(II) being oxidized to Mn(III), whereas colloidal manganese dioxide might be a key intermediate for the reoxidation of Cr(III) to Cr(VI).

Simultaneous determination of methylphenobarbital enantiomers and phenobarbital in human plasma by on-line coupling of an achiral precolumn to a chiral liquid chromatographic column

A fully automated liquid chromatographic (LC) method for the simultaneous determination of methylphenobarbital enantiomers and phenobarbital in human plasma has been developed. The method is based on the use of a precolumn packed with an internal-surface reversed-phase packing material (LiChrospher ADS) for sample clean-up coupled to LC analysis on a cellulose tris(4-methylbenzoate) based chiral stationary phase (Chiralcel OJ-R). A 100-μl plasma sample was injected directly on the precolumn packed with LiChrospher RP-18 ADS using a mixture of pH 5.0 phosphate buffer–methanol (97:3, v/v) as washing liquid. The analytes were then eluted in the back-flush mode with the LC mobile phase. The enantiomeric separation of methylphenobarbital was achieved on Chiralcel OJ-R. The retention times were modelled using a D-optimal design with ten experimental points in order to optimise the LC mobile phase for the separation of phenobarbital from the enantiomers of mephobarbital. The factors selected were the acetonitrile content, the pH and the sodium perchlorate concentration in the mobile phase. A Derringer's desirability function was used to find an optimal and robust solution within the experimental domain. The mobile phase selected consisted of a mixture of pH 7.0 phosphate buffer–acetonitrile (60:40, v/v). The elution profiles of phenobarbital, methylphenobarbital and blank plasma samples on the precolumn and the time needed for analyte transfer from the precolumn to the analytical column were then determined. Finally, the method developed was validated.

Simultaneous determination of pirlindole enantiomers and dehydropirlindole by chiral liquid chromatography

Liquid chromatography was employed for the determination of pirlindole enantiomers and its oxidation product dehydropirlindole (DHP). The direct separation of pirlindole enantiomers and DHP was achieved on a cellulose tris-(3,5-dimethylphenylcarbamate) chiral stationary phase (Chiralcel OD-R). Acetonitrile was used as the organic modifier and sodium perchlorate was used as an ionic additive in the mobile phase. The influence of acetonitrile and sodium perchlorate concentrations on enantioselectivity and achiral selectivity towards DHP was investigated in order to find suitable conditions for the determination of low amounts of each analyte. The mobile phase selected consisted of a mixture of acetonitrile and phosphate buffer (pH 5.0) containing sodium perchlorate (0.05 M) (35:65, v/v) and the UV detector was set at 220 nm. The method developed was validated and was found to be linear in the 0.1–5 μg ml −1 range ( r 2=0.999 for the three compounds). Repeatability and the intermediate precision for the three analytes at a concentration of 0.1 μg ml −1 were about 3 and 4%, respectively. This concentration corresponds to the quantification of 0.1% for the minor enantiomer. Actual determinations of enantiomeric purity for single enantiomers of pirlindole were performed.

Spectrophotometric determination of cysteine andN-acetylcysteine in pharmaceutical preparations

An accurate fast spectrophotometric method for the determination of cysteine andN-acetyl-cysteine is presented, based on the oxidation of these amino acids by ferric ions in the presence of ferrozine, whereby a violet-coloured complex is formed which absorbs at 562 nm. The method was satisfactory for the determination of cysteine andN-acetylcysteine in samples within the range 0.02–6.00 μgml−1. Effects of time, acidity, ferric ions, ferrozine, sodium perchlorate concentrations and the tolerance limit for other amino acids have been reported. The method was applied to the determination of cysteine in amino acids mixtures andN-acetylcysteine in pharmaceutical preparations.

The ionic product of water in highly concentrated sodium perchlorate solutions

The ionic product of water, p K w=−log[H +][OH −], has been determined in aqueous solutions of sodium perchlorate over the concentration range of 1.0–8.0 M at 25°C from high-precision potentiometric titrations carried out in cells with liquid junction using both glass and hydrogen electrodes. The glass electrode results are systematically lower probably as a result of interference by Na + ions.