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PubMedDate not supplied

Measurement of bromate in bottled water by high-performance liquid chromatography with post-column flow reactor detection.

The objective of this work was to develop a reliable, rugged high-performance liquid chromatographic (HPLC) method for determination of trace levels of bromate (< 10 micrograms/l) in bottled water. HPLC separation was achieved by ion interaction chromatography using a C-18 reversed-phase column and a mobile phase consisting of methanol/water (20:80, v/v) with tetrabutylammonium acetate as the ion interaction reagent. A post-column reaction based on oxidation of o-dianisidine in acidic solution to a product detected at 500 nm provided selective measurement of the oxidants. The limit of detection and the limit of quantitation were 1 and 3 micrograms/l, respectively. Iodate, chlorite, and nitrite were chromatographically separated from bromate and measured by monitoring the post-column reaction. Chloride and chlorate at levels that might be found in bottled water did not interfere with the determination of bromate. Bromate was detected in bottled waters at concentrations up to 40 micrograms/l.

Bromates↗
PubMedDate not supplied

An improved formulation of the zirconyl hematoxylin stain for acidic mucins.

Zirconyl hematoxylin stains acidic mucins darkly and specifically using a solution of 100 mg hematoxylin, 5 ml ethanol, 5 ml 0.5% sodium iodate, 400 mg zirconyl chloride octahydrate, and 30 ml 25% aqueous glycerol. The stain is especially advantageous for studying goblet cells and Paget cells.

Animals↗
PubMed1991

Comparison of toxicity induced by iodine and iodide in male and female rats.

In risk assessments the various forms of iodine have been treated as if they were toxicologically equivalent. While iodide (I-) and iodate (IO3-) have been studied, no studies concerned with the subchronic toxicity of iodine (I2) have been conducted in experimental animals. This study examined toxicities associated with iodine. Rats were treated with 0, 1, 3, 10, and 100 mg/l of either iodine or iodide (as Nal) in the drinking water for 100 d. Treatment had no effect on body, brain, or heart weights in either sex, or on testes weights in male rats. Although differences in kidney and liver weights were noted, they did not appear to be treatment related. Thyroid weight in male rats was significantly increased with an increasing concentration of iodide in the water, but not iodine. In contrast, thyroid weight decreased at the highest dose of iodide in female rats. Hematocrit, hemoglobin, and blood urea nitrogen (BUN) values were relatively constant and did not vary with treatment. There were no significant differences in AST, ALT, cholesterol, and triglyceride values. After 10 d on treatment a dose-related trend in increased plasma T4 concentrations was observed in both sexes treated with iodine. Statistically significant increases in the T4/T3 ratio in both sexes was also noted with iodine treatment. This increase was maintained for 100 d of treatment. Iodide did not produce this effect at 10 d. Although there was a significant increase in T4/T3 ratios in female rats after 100 d of treatment with iodide, the magnitude of the changes was smaller than that observed with iodine treatments. The results of this study indicate that iodine and iodide affect thyroid hormone status in substantially different ways.

Animals↗
PubMed1986

Oxidative destruction of hydrazines produces N-nitrosamines and other mutagenic species.

As part of the joint International Agency for Research on Cancer-National Cancer Institute program for the evaluation and development of methods for the degradation of chemical carcinogens, four oxidative techniques for the degradation of hydrazines were investigated. The oxidizing agents used were as follows: sodium hypochlorite, calcium hypochlorite, potassium iodate, and potassium permanganate in sulfuric acid. In each case, at least 99% of the hydrazine initially present was destroyed; however, the potential usefulness of these methods was compromised by the formation (in some reaction mixtures) of carcinogenic N-nitroso compounds and/or unknown mutagenic species. Oxidative degradation of hydrazines is recommended only for the decontamination of glassware and for the treatment of spills, for which reductive degradation methods are not suitable.

Animals↗
PubMed1994

The adherence of three Streptococcus bovis strains to cells of rumen epithelium primoculture under various conditions.

Three Streptococcus bovis strains were tested in biotype assay and examined for the adherence to cells of rumen epithelium primoculture. The adherence pattern of ruminal streptococci in phosphate buffered saline at pH values ranging from 4.1 to 8.5 was determined. Our isolates of Streptococcus bovis strains adhered best at pH 7.0-7.3. To characterize the adhesive determinants, the bacterial cells were exposed to various treatments. Protease treatment dramatically decreased the adherence of all Streptococcus bovis strains, thus suggesting that the determinants responsible for the adherence are largely proteinaceous. Carbohydrates could be also significantly involved in the active sites of bacterial surface because metaperiodate-treated cells adhered much more poorly than control, sodium iodate-treated cells. Addition of carbohydrates (lactose, maltose and saccharose) had no significant effect on the adherence of Streptococcus bovis strains although a slight decrease in the adhesion was detected.

Animals↗
PubMed2004

Dual fortification of salt with iodine and micronized ferric pyrophosphate: a randomized, double-blind, controlled trial.

BACKGROUND: In many developing countries, children are at high risk for both goiter and anemia. In areas of subsistence farming in rural Africa, salt is one of the few regularly purchased food items and could be a good fortification vehicle for iodine and iron, provided that a stable yet bioavailable iron fortificant is used. OBJECTIVE: We tested the efficacy of salt dual-fortified with iodine and micronized ferric pyrophosphate for reducing the prevalence of iodine and iron deficiencies in children. DESIGN: In rural northern Morocco, we fortified local salt with 25 microg I (as potassium iodate)/g salt and 2 mg Fe (as micronized ferric pyrophosphate; mean particle size = 2.5 microm)/g salt. After storage and acceptability trials, we compared the efficacy of the dual-fortified salt (DFS) with that of iodized salt in a 10-mo, randomized, double-blind trial in iodine-deficient 6-15-y-old children (n = 158) with a high prevalence of anemia. RESULTS: After storage for 6 mo, there were no significant differences in iodine content or color lightness between the DFS and iodized salt. During the efficacy trial, the DFS provided approximately 18 mg Fe/d; iron absorption was estimated to be approximately 2%. After 10 mo of treatment in the DFS group, mean hemoglobin increased by 16 g/L (P < 0.01), iron status and body iron stores increased significantly (P < 0.01), and the prevalence of iron deficiency anemia decreased from 30% at baseline to 5% (P < 0.001). In both groups, urinary iodine (P < 0.001) and thyroid volume (P < 0.01) improved significantly from baseline. CONCLUSION: A DFS containing iodine and micronized ferric pyrophosphate can be an effective fortification strategy in rural Africa.

Adolescent↗
PubMed2004

Triple fortification of salt with microcapsules of iodine, iron, and vitamin A.

BACKGROUND: In many developing countries, children are at high risk of goiter, vitamin A deficiency, and iron deficiency anemia. OBJECTIVE: We aimed to develop a stable, efficacious salt fortified with iodine, iron, and vitamin A. DESIGN: A novel spray-cooling technique was used with hydrogenated palm oil to package potassium iodate, micronized ferric pyrophosphate, and retinyl palmitate into microcapsules (mean particle size: 100 mum). We used the microcapsules to create triple-fortified salt (TFS) with 30 mug I, 2 mg Fe, and 60 mug vitamin A/g salt. After storage trials, we compared the efficacy of TFS with that of iodized salt in a 10-mo, randomized, double-blind trial in goitrous schoolchildren (n = 157) who had a high prevalence of vitamin A deficiency and iron deficiency anemia. RESULTS: After storage for 6 mo, losses of iodine and vitamin A from the TFS were approximately 12-15%, and color was stable. In the TFS group, mean hemoglobin increased by 15 g/L at 10 mo (P < 0.01), iron status indexes and body iron stores improved significantly (P < 0.05), and mean serum retinol, retinol-binding protein, and the ratio of retinol-binding protein to prealbumin increased significantly (P < 0.01). At 10 mo, prevalences of vitamin A deficiency and iron deficiency anemia were significantly lower in the TFS group than in the iodized salt group (P < 0.001). CONCLUSION: Newly developed microcapsules containing iodine, iron, and vitamin A are highly stable when added to local African salt. TFS was efficacious in reducing the prevalence of iron, iodine, and vitamin A deficiencies in school-age children.

Adolescent↗
PubMed2002

Effects of oxidizing adulterants on detection of 11-nor-delta9-THC-9-carboxylic acid in urine.

Bleach, nitrite, chromate, and hydrogen peroxide-peroxidase are effective urine adulterants used by the illicit drug users to conceal marijuana-positive results. Methods for detecting nitrite and chromate are available. Effects of other oxidizing agents that could possibly be used as adulterants and are difficult to detect or measure are presented in this report. Urine samples containing 40 ng/mL of 11-nor-delta9-THC-9-carboxylic acid (THC-acid) were treated with 10 mmol/L of commonly available oxidizing agents. Effects of horseradish peroxidase of activity 10 unit/mL and extracts from 2.5 g of red radish (Raphanus sativus, Radicula group), horseradish (Armoracia rusticana), Japanese radish (Raphanus sativus, Daikon group), and black mustard seeds (Brassica nigra), all with 10 mmol/L of hydrogen peroxide, were also examined. After 5 min, 16 h and 48 h of exposure at room temperature (23 degrees C) the specimens were tested by a gas chromatographic-mass spectrometric method for THC-acid. A control group treated with sodium hydrosulfite to reduce the oxidants, was also tested to investigate the effect of oxidizing agents on THC-acid in the extraction method. THC-acid was lost completely in the extraction method when treated with chromate, nitrite, oxone, and hydrogen peroxide/ferrous ammonium sulfate (Fenton's reagent). Some losses were also observed with persulfate and periodate (up to 25%). These oxidants, and other oxidizing agents like permanganate, periodate, peroxidase, and extracts from red radish, horseradish, Japanese radish and black mustard seeds destroyed most of the THC-acid (> 94%) within 48 h of exposure. Chlorate, perchlorate, iodate, and oxychloride under these conditions showed little or no effect. Complete loss was observed when THC-acid was exposed to 50 mmol/L of oxychloride for 48 h. Several oxidizing adulterants that are difficult to test by the present urine adulterant testing methods showed considerable effects on the destruction of THC-acid. The time and temperature for these effects were similar to those used by most laboratories to collect and test specimens. In several cases, the loss of THC-acid was > 94%.

Armoracia↗
PubMed2004

Six spectroscopic methods for detection of oxidants in urine: implication in differentiation of normal and adulterated urine.

Six separate methods to detect oxidants in urine were developed. The presence of the oxidants was established by initial oxidation of ferrous to ferric ion and detecting the ferric by chromogenic oxidation or complex formation. The reagents for chromogenic oxidation were N,N-dimethylamoino-1,4-phenylenediamine (DMPDA), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS), and 2-amino-p-cresol (APC), and the reagents for the chromogenic complex were xylenol orange (XO), 8-hydroxy-7-iodo-5-quinolinesulfonic acid (HIQSA), and 4,5-dihydroxy-1,3-benzene-di-sulfonic acid (HBSA). All methods showed comparable results when tested for ferric, chromate, permanganate, oxychloride, hydrogen peroxide, oxone, tert-butylhydroperoxide, and cumenehydroperoxide at a concentration of 1.0 mmol/L in water (CV < 7%). The nitrite results are comparable only with DMPDA and APC. Periodate responded to the highest oxidation number (ON = 8) by chromogenic oxidation but lowest (ON = 2) by the chromogenic complex. The iodate responded only to the chromogenic oxidation with ON = 6. The linearity of the procedures was established by chromate in water. The linear concentrations were 0.09-12.00 mE/L for DMPDA, ABTS, APC, and HBSA and 0.09-6.00 mE/L for XO and HIQSA. In all methods, the correlation coefficients were > or = 0.9991 and precisions were within +/- 5.6%. The methods were used to test oxidants in 238 urine specimens. The chromate at 3.0 mE/L in water was used as standard. The correlation coefficients of 0.9600-0.9853 and the ANOVA test (F = 0.90, F(critical) = 2.22 at P(0.48)) indicated that the methods correlated well. The median concentration of oxidants in the specimens was 0.21 mE/L with an average and standard deviation of 0.62 +/- 1.19 (range 0.04-8.83 mE/L). When Grubbs' statistical test was applied to the specimen results, no specimen was found to be outlier or could be considered as adulterated. The Grubbs' test also revealed that the threshold concentration to identify urine adulteration was 29 mE/L at confidence level of 99%.

Chromogenic Compounds↗
PubMed2005

Spectrophotometric detection of iodide and chromic (III) in urine after oxidation to iodine and chromate (VI).

Tests for oxidizing adulterants in urine are a continuing challenge to the drug-testing program. Iodine was found to destroy morphine and 6-acetylmorphine almost immediately. The effects were less evident on 11 -nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THC-acid). When the urine solution was tested for iodine by a chromogenic substrate, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), no iodine was detected. Masking drug and adulterant simultaneously made iodine a preferred oxidizing adulterant for drug abusers. In this study, the reduced iodide was oxidized by sodium nitrite to iodine. The excess nitrite was decomposed by sulfamic acid and the iodine was detected by ABTS. Linearity was 12.7 to 635 mg/L (0.1 to 5 mmol/L, y = 0.9966x + 0.0016, R2 = 1.0000). Precisions (coefficient of variation) were within +/- 4.1% and quantitative accuracies were within 97% of expected values (n=5). Chromate, iodate, periodate, and persulfate interfered with the method. To alleviate the problem, the positive specimens were tested again by an iodine-specific method. After oxidation, the samples were treated with sodium azide and ammonium thiocyanate. In presence of thiocyanate, the azide reduced iodine to iodide almost immediately, and the solutions showed negative response to ABTS. The results were compared with that of a control group tested without thiocyanate. When iodine was present, the ratios of thiocyanate to control were less than 6%. Chromate was also found to destroy THC-acid in urine, and during storage most of the chromate changed to chromic (III). In this study, chromic was oxidized to chromate by hydrogen peroxide and sodium hydroxide and detected by 1,5-diphenylcarbazide. Linearity was 5.2 to 156 mg/L (0.1 to 3.0 mmol/L, y = 1.0285x - 0.0034, R2 = 0.9998). Precisions were within +/- 8.5% and quantitative accuracies were within 92% of expected values (n=5). The test was not interfered by other oxidizing agents. Both iodide and chromic oxidation methods showed urine backgrounds less than 1.27 and 0.52 mg/L, respectively (< 0.01 mmol/L). It indicated that a response more than 10 times of the background could be considered as oxidant contamination or adulteration of urine specimens.

Chromium↗
PubMed2003

Prevalence and risk factors of iodine deficiency among schoolchildren.

The aim of this study was to demonstrate the prevalence of iodine deficiency among schoolchildren and the risk factors influencing it. One thousand five hundred and seventy-three schoolchildren were chosen from 14 schools in seven different regions in Istanbul. After all data relating to sociodemographic factors and the use of iodized salt were recorded, iodine contents of urine samples were determined by the Sandell Kolthoff reaction. Chi-squared and multiple regression analysis were used for the investigation of the correlation between iodine deficiency and risk factors. The prevalence of goitre (> or = 2 grade) was 1.9 per cent. The median urine iodine level was in the normal range (10.5 microg/dl). In 46.2 per cent of the students the urine iodine levels were below 10 microg/dl and 13.9 per cent of the students had urine iodine levels below 5 microg/dl. The prevalence of iodine deficiency was significantly higher in younger (< or = 10 years) children, in children with less educated mothers and fathers, and with poorer and more crowded families (p < 0.01, p < 0.01 and p < 0.01, p < 0.001, respectively). The rate of iodine deficiency was significantly higher in females than in males and also higher in children who lived on the European side of Istanbul than on the Anatolian side of Istanbul (p < 0.0001, p < 0.0001, respectively). The rate of use of iodized salt was 44.4 per cent and the iodine deficiency rate was not affected by the use of iodized salt (p > 0.05). Although the median urine iodine level was in the normal range, in 46.2 per cent of the students urine iodine levels were low (< 10 microg/dl). As there seems to be no effect from the use of iodized salt in iodine deficiency, the use of a more stable potassium iodate for the fortification of salt may be required.

Adolescent↗
PubMed1990

Rapid preparation of 123I-labelled methylene blue and toluidine blue: potential new agents for parathyroid scintigraphy.

Methylene blue and toluidine blue are phenothiazinium dyes used to localize parathyroid glands visually during surgery. For the purpose of assessing the potential of radiolabelled analogues for scintigraphic localization of parathyroids, a rapid and convenient method has been developed for covalently labelling the dyes with iodine-123. Treatment of aqueous methylene blue or toluidine blue with 123I-sodium iodide in the presence of potassium iodate and hydrochloric acid at 100 degrees C for 1 h results in incorporation of 80-90% of the radioiodine into the dye. The chemical and radiochemical impurities are readily removed by passage through a disposable sample preparation column. Using the optimized protocol, a sterile, pyrogen-free multi-dose solution of radioiodinated dye (pH 7, specific activity greater than or equal to 37 MBq mg-1, radioactivity concentration congruent to 37 MBq ml-1, radiochemical purity greater than 99%, overall activity yield available for injection 60-70%) can be prepared within 1.5 h.

Humans↗
PubMed2006

Electric field induced instabilities: waves and stationary patterns.

We examine a prototypical ionic reaction-diffusion system involving the well-known iodate-arsenous acid reaction in an electric field at a constant current density. By taking into consideration of the spatial inhomogeneities in electric field intensity and charge density due to ionic migration and diffusion using charge balance condition, we look for the different instability regions in the appropriate parameter space. We show that the model admits of both absolute and convective instability resulting in the development of propagating waves and also stationary spatial patterns at times.

Journal Article↗
PubMed2003

Pattern of reaction diffusion fronts in laminar flows.

Autocatalytic reaction between reacted and unreacted species may propagate as solitary waves, namely, at a constant front velocity and with a stationary concentration profile, resulting from a balance between molecular diffusion and chemical reaction. The effect of advective flow on the autocatalytic reaction between iodate and arsenous acid in cylindrical tubes and Hele-Shaw cells is analyzed experimentally and numerically using lattice Bhatnagar-Gross-Krook simulations. We do observe the existence of solitary waves with concentration profiles exhibiting a cusp and we delineate the eikonal and mixing regimes recently predicted.

Animals↗
PubMed1972

Nitrate Reductase and Chlorate Toxicity in Chlorella vulgaris Beijerinck.

A study of the growth-inhibiting effect of chlorate on the Berlin strain of Chlorella vulgaris Beijerinck provided complete confirmation of the theory of chlorate toxicity first proposed by Aberg in 1947. Chlorate was toxic to the cells growing on nitrate, and relatively nontoxic to the cells growing on ammonium. The latter cells contained only 0.01 as much NADH-nitrate reductase as the nitrate-grown cells. Chlorate could substitute for nitrate as a substrate of the purified nitrate reductase with Km = 1.2 mm, and V(max) = 0.9V(max) for nitrate. Bromate, and to a much smaller extent, iodate, also served as alternate substrates. Nitrate is a reversible competitive inhibitor of chlorate reduction, which accounts for the partial reversal, by high nitrate concentrations, of the observed inhibition of cell growth by chlorate. During the reduction of chlorate by NADH in the presence of purified nitrate reductase, there was a progressive, irreversible inhibition of the enzyme activity, presumably brought about by the reduction product, chlorite. Both the NADH-nitrate reductase activity and the associated NADH-cytochrome c reductase activity were inactivated to the same extent by added chlorite. The spectral properties of the cytochrome b(557) associated with the purified enzyme were not affected by chlorite. The inactivation of the nitrate reductase by chlorite could account for the toxicity of chlorate to cells grown on nitrate, though the destruction of other cell components by chlorite or its decomposition products cannot be excluded.

Journal Article↗
PubMed1983

Root absorption and transport behavior of technetium in soybean.

The absorption characteristics and mechanisms of pertechnetate (TcO(4) (-)) uptake by hydroponically grown soybean seedlings (Glycine max cv Williams) were determined. Absorption from 10 micromolar solutions was linear for at least 6 hours, with 30% of the absorbed TcO(4) (-) being transferred to the shoot. Evaluation of concentration-dependent absorption rates from solutions containing 0.02 to 10 micromolar TcO(4) (-) shows the presence of multiphasic absorption isotherms with calculated K(s) values of 0.09, 8.9, and 54 micromolar for intact seedlings. The uptake of TcO(4) (-) was inhibited by a 4-fold concentration excess of sulfate, phosphate, selenate, molybdate, and permanganate; no reduction was noted with borate, nitrate, tungstate, perrhenate, iodate, or vanadate. Analyses of the kinetics of interaction between TcO(4) (-) and inhibiting anions show permanganate to be a noncompetitive inhibitor, while sulfate, phosphate, and selenate, and molybdate exhibit characteristics of competitive inhibitors of TcO(4) (-) transport suggesting involvement of a common transport process.

Journal Article↗
PubMed1990

Spinach Nitrate Reductase : Effects of Ionic Strength and pH on the Full and Partial Enzyme Activities.

Initial velocity studies of immunopurified spinach nitrate reductase have been performed under conditions of controlled ionic strength and pH and in the absence of chloride ions. Increased ionic strength stimulated NADH:ferricyanide reductase and reduced flavin:nitrate reductase activities and inhibited NADH:nitrate reductase, NADH:cytochrome c reductase and reduced methyl viologen:nitrate reductase activities. NADH:dichlorophenolindophenol reductase activity was unaffected by changes in ionic strength. All of the partial activities, expressed in terms of micromole 2 electron transferred per minute per nanomole heme, were faster than the overall full, NADH:nitrate reductase activity indicating that none of the partial activities included the rate limiting step in electron transfer from NADH to nitrate. The pH optimum for NADH:nitrate reductase activity was determined to be 7 while values for the various partial activities ranged from 6.5 to 7.5. Chlorate, bromate, and iodate were determined to be alternate electron acceptors for the reduced enzyme. These results indicate that unlike the enzyme from Chlorella vulgaris, intramolecular electron transfer between reduced heme and Mo is not rate limiting for spinach nitrate reductase.

Journal Article↗
PubMed2005

Cerium triiodate, Ce(IO(3))(3).

The crystal structure of Ce(IO3)3 consists of one-dimensional chains of edge-sharing CeO9 polyhedra which are crosslinked into two-dimensional layers through bridging IO3- groups. The layers are held together via long I...O contacts, resulting in an extended three-dimensional network. The I-O bond distances and O-I-O angles are normal, lying in the ranges 1.806 (4)-1.846 (4) A and 89.9 (2)-100.9 (2) degrees, respectively. The three crystallographically independent iodate groups all show different coordination modes.

Journal Article↗