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PubMedDate not supplied

The effects of subchronic chlorate exposure in Sprague-Dawley rats.

Male and female Sprague-Dawley rats were exposed to drinking water containing 3.0, 12.0 or 48.0 mM sodium chlorate. The mean drinking water consumption varied between exposure groups from 100-200 ml/kg/day. Female exposure groups consistently drank more water (23-42%) than male exposure groups thereby receiving more chlorate/kg/day at every exposure level. There were no compound related deaths; however, both males and females in the high exposure groups had significant weight loss during the 90-day exposure period. Also, in these same groups females had mild but significant decreases in the following relative organ weights; adrenals, thymus and spleen, while the relative brain weight was increased. In males, the heart, kidneys and liver were mildly decreased while the brain and testes were mildly increased. Red blood cell counts and percent hematocrit were decreased in both sexes in the high dose group. Pituitary gland (pars distalis) vacuolization and thyroid gland colloid depletion were prominent in both sexes in mid and/or high dose animals. A NOAEL of 0.36 mM chlorate/kg b.w./day in males and 0.50 mM chlorate/kg b.w./day in females were established.

Animals↗
PubMed2000

Isolation and characterization of transposon-induced chlorate resistant mutants of the cyanobacterium Anabaena species PCC 7120.

Mutants of Anabaena sp. PCC 7120 resistant to chlorate were isolated using transposon mutagenesis. The Anabaena population of 5 x 10(7) cells ml(-1) and log phase Escherichia coli cultures in undisturbed conditions produced maximum exconjugants. Nitrate-promoted growth and cellular constituents observed in the parent were absent in the mutants. Nitrate repressed heterocyst formation and N2-fixation in the parent, but had little or no effect on the mutants.

Anabaena↗
PubMed2003

Cranial MR imaging findings of potassium chlorate intoxication.

We present the case of a patient who attempted suicide by ingesting matchstick heads (55% potassium chlorate). The patient presented to the emergency room with loss of consciousness, and MR imaging revealed symmetric hyperintense signal within the deep gray matter and medial temporal lobes. The patient improved after undergoing conventional treatment and hyperbaric oxygen.

Adult↗
PubMedDate not supplied

The kinetics of chlorite and chlorate in rats.

Chlorine dioxide (ClO2) is under consideration as an alternative to chlorination as a disinfectant for public water supplies. The primary products resulting from ClO2 disinfection of surface waters are chlorite (ClO2-) and chlorates (ClO3-). The kinetics of 36ClO2- and 36ClO3- was studied in rats. Radioactivity was rapidly absorbed from the gastrointestinal tract following the administration of (0.17 microCi) 36ClO2- or (0.85 microCi) 36ClO3- orally; and 36Cl in plasma reached a peak at 2 hr and 1 hr, respectively. After 72 hr, radioactivity was highest in whole blood, followed by packed cells, plasma, stomach, testes, skin, lung, kidney, duodenum, carcass, spleen, ileum, brain, bone marrow and liver in 36ClO2- treatment. 36Cl excretion was greatest at 24 hr after the administration of 36ClO3-, but in the 36ClO2-, the excretion most likely represented saturation of the biotransformation and excretion pathways. About 40% of the total initial dose was excreted at 72 hr in the urine and feces in both treatments. No 36Cl was detected in expired air throughout the 72 hr studied.

Animals↗
PubMed1984

Effects of the acute rising dose administration of chlorine dioxide, chlorate and chlorite to normal healthy adult male volunteers.

Chlorine dioxide is under consideration for use as a water disinfectant alternative to chlorination in the United States. A rising dose tolerance study was undertaken to assess the relative safety and tolerance of acute administration of chlorine dioxide and its byproducts, chlorite and chlorate, to normal healthy adult male volunteers. In evaluation of an extensive battery of laboratory tests and vital signs, no adverse physiological effects were identified. This provided a data base upon which a controlled 5-month study trial of these substances in normal healthy volunteer subjects was designed.

Adult↗
PubMed1984

The effects of chronic administration of chlorine dioxide, chlorite and chlorate to normal healthy adult male volunteers.

The physiological impact of chronic 12 week ingestion of chlorine dioxide and its byproducts, chlorite and chlorate, was compared to the effects of chlorine, chloramine and untreated water. The water disinfectant solutions were administered daily (500 ml, 5 ppm) to normal healthy adult male volunteers. An extensive battery of tests was used to evaluate the physiological impact of the ingested water disinfectants. Upon analysis of both quantitative and qualitative parameters it was concluded that the 12 week chronic administration of chlorine dioxide and its byproducts was accompanied by no clinically important physiological effects.

Adult↗
PubMed2001

Effect of beta radiation on the crystallization of sodium chlorate from water: a new type of asymmetric synthesis.

Sodium chlorate is an achiral molecule that crystallizes from water in the chiral space group P2(1)3. In the absence of chiral perturbations, a random distribution of (+) and (-) crystals is obtained. Kondepudi(2) has shown that constantly stirring an evaporating NaClO(3) solution gives mostly either (+) or (-) crystals. Repeating this experiment many times gives equal numbers of (+) and (-) sets of crystals. Herein we report that when evaporating aqueous NaClO(3) is subjected to beta particles from an Sr-90 source, an asymmetric distribution of (+) and (-) crystals favoring the (+) crystals is obtained. The beta particles are energetic polarized electrons that are approximately 80% of left-handed helicity. By a poorly understood mechanism, the spin polarized electrons produce chiral nucleating sites that favor formation of the (+)-NaClO(3) crystals. Exposure of the evaporating solution instead to energetic positrons from an Na-22 source yields mainly (-)-NaClO(3) crystals. Polarized positrons are of predominantly right-handed helicity. One may conclude that the chirality of the radiation is correlated with the chirality of the crystals being generated.

Journal Article↗
PubMed2003

The chlorate-resistant and photomorphogenesis-defective mutant cr88 encodes a chloroplast-targeted HSP90.

The cr88 mutant of Arabidopsis is a novel chlorate-resistant mutant that displays long hypocotyls in red light, but not in far red or blue light, and is delayed in the greening process. In cotyledons and young leaves, plastids are less developed compared with those of the wild type. In addition, a subset of light-regulated genes are under-expressed in this mutant. To understand the pleiotropic phenotypes of cr88, we isolated the CR88 gene through map-based cloning. We found that CR88 encodes a chloroplast-targeted 90-kDa heat shock protein (HSP90). The CR88 gene is expressed at highest levels during early post-germination stages and in leaves and reproductive organs. It is constitutively expressed but is also light and heat shock inducible. Chloroplast import experiments showed that the protein is localized to the stroma compartment of the chloroplast. The possible function of an HSP90 in the chloroplast and a plausible explanation of the pleiotropic phenotypes observed in cr88 are discussed.

Amino Acid Sequence↗
PubMed1982

Lung carcinogenesis by procarbazine chlorate in BALB/c mice.

A study of the carcinogenic action of procarbazine chlorate in BALB/c/Cb/Se mice showed that this substance significantly increases the incidence or lung tumours in both sexes. The induced tumors were alveolar-lining, papillary and alveolar-papillary type carcinomas with a tendency to invade the bronchial wall.

Animals↗
PubMed2003

Enhancement of neurite outgrowth-promoting activity by heparin derivatives in sodium chlorate-treated explant cultures of rat central neurons.

Periodate-oxidized/borohydride-reduced 2-O-desulfated heparin (OR2DSH) was prepared using intact heparin from pig intestine as the starting material. Successive treatments of the heparin by oxidation with sodium periodate and reduction with sodium borohydride yielded periodate-oxidized/borohydride-reduced heparin (OR-heparin). Subsequent 2-O-desulfation of OR-heparin, according to a previously established method, yielded OR2DSH. Digestion of OR2DSH with heparitinases generated unsaturated disaccharides, comprising 86.5% DeltaDiHS-(6,N)S (DeltaUA1-->4GlcNS(6S)) and 13.5% DeltaDiHS-NS (DeltaUA1-->4GlcNS), as well as undigested oligosaccharides in which uronate moieties were derivatized by the cleavage of the covalent bond between the C-2 and C-3 positions by periodate-oxidation. The molecular mass of OR2DSH was determined to be 11 kDa, which is almost the same as those of other heparin derivatives such as 2-O-desulfated heparin (2DSH), 6-O-desulfated heparin (6DSH) and N-desulfated N-reacetylated heparin (NDSNAc-heparin). The ability of OR2DSH to enhance neurite outgrowth-promoting activity was evaluated using the explant culture of neocortical tissue from rat embryo in which endogenous heparan sulfate at the cell surface lost substantial numbers of sulfate groups by the action of 40 micro M sodium chlorate. The maximum activity of OR2DSH (29.7%) was achieved at 10 micro g/ml, and those of OR-heparin (21.7%), 2DSH (18.7%) and intact heparin (16.3%) were 100 micro g/ml, whereas that of NDSNAc-heparin (16.5%) was 1,000 micro g/ml. Completely 6-O-desulfated heparin (100:6DSH) exhibited very weak activity (3.3%) at 1,000 micro g/ml. These results suggest that the potency of OR2DSH to enhance neurite outgrowth-promoting activity is exerted synergetically by two different components in OR2DSH, i.e., the IdoA alpha1-->4GlcNS(6S) unit, which contains 6-O- and 2-N-sulfate groups, and the uronate moiety in which the covalent bond between C-2 and C-3 is cleaved, although the mode of action remains to be clarified.

Animals↗
PubMed1996

Chlorate as a Transport Analog for Nitrate Absorption by Roots of Tomato.

Several studies have indicated that chlorate (ClO3-) and nitrate (NO3-) may share a common transport system in higher plants. Here, we compared the interactions between ClO3- and NO3-uptake by roots of intact tomato (Lycopersicon esculentum cv T5) plants. Exposure to ClO3- for more than 2 h inhibited both net ClO3- and K+ uptake, presumably because of ClO3- toxicity; consequently, subsequent measurements were conducted after short exposures to ClO3-. The apparent affinity and apparent maximum rate of absorption for net ClO3- and NO3- uptake were very similar. Interactions between ClO3- and NO3- transport were complex; 50 [mu]M NO3- acted as a mixed inhibitor of net ClO3- uptake, but 50 [mu]M ClO3- had no significant effect on net NO3- uptake, and 500 [mu]M ClO3- had no significant effect on 15NO3- influx. If the two ions share a single common high-affinity transport system, it is much more selective for NO3- than would be suggested by the similarity of net NO3- and ClO3- uptake kinetics. Our results indicate that, although NO3- may interfere with root ClO3- uptake, ClO3- is not a useful analog for the root high-affinity NO3- transport system.

Journal Article↗
PubMed1983

Inhibition of chemoautotrophic nitrification by sodium chlorate and sodium chlorite: a reexamination.

The oxidation of NH(4) by Nitrosomonas europaea was insensitive to 10 mM NaClO(3) (sodium chlorate) but was strongly inhibited by NaClO(2) (sodium chlorite; K(i), 2 muM). The oxidation of NO(2) by Nitrobacter winogradskyi was inhibited by both ClO(3) and ClO(2) (K(i) for ClO(2), 100 muM). N. winogradskyi reduced ClO(3) to ClO(2) under both aerobic and anaerobic conditions, and as much as 0.25 mM ClO(2) was detected in the culture filtrate. In mixed N. europaea-N. winogradskyi cell suspensions, the oxidation of both NH(4) and NO(2) was inhibited in the presence of 10 mM ClO(3) after a 2-h lag period, despite the fact that, under these conditions, ClO(2) was not detected in the filtrate. The data are consistent with the hypothesis that, in mixed culture, NH(4) oxidation is inhibited by ClO(2) produced by reduction of ClO(3) by the NO(2) oxidizer. The use of ClO(3) inhibition of NO(2) oxidation in assays of nitrification by mixed populations necessitates cautious interpretation unless it can be shown that the oxidation of NH(4) is not affected.

Journal Article↗
PubMed2003

[Female workers health: the case of a laundry at a sodium chlorate factory].

This article presents a case study on working and health conditions of female workers and former workers in the laundry at a sodium chlorate plant. The women's main function was to wash uniforms of workmen who handled metallic mercury during production and maintenance. The aim of this study is to show the health effects of this work process by analyzing workplace conditions, evaluating clinical aspects in the women, and performing individual interviews in order to obtain more precise information based on their personal experience. The authors demonstrate how harmful this type of work is to the women workers' health, posing a serious risk for them in particular and workers' conditions in general in the factory. They also point out that most of what is known about women's occupational activity (in terms of its contents and risks), in addition to their specific problems and different diseases, may be disguised by gender relationships.

English Abstract↗