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PubMed2004

[Induction and reversibility of thyroid proliferative changes in suckling rats given thiocyanate].

Potassium thiocyanate given in the drinking water of pregnant rats led to decreased body weight in their 14-day-old offspring (27%) without altering thyroid weight. Reduction of the suckling rat's body weight could be explained be defective thyroxinemia (38). Plasma FT3 and TSH were unchanged after thiocyanate treatment. The biochemical changes were in agreement with the histological aspects of the hypothyroid animals. The typical pattern was hyperplastic goiter. Colloid volume was reduced compared with controls. Presence of resorbed peripheral vacuoles, a sign of thyroid hyperactivity, was disclosed by a three-fold increase in radioiodide (131I) uptake compared with controls. When the antithyroid drug was removed from the mother's milk, the pups'weight increased but did not reach control values. Plasma thyroid hormone levels returned to normal and even exceeded control values in spite of partial recovery of thyroid iodine content when thiocyanate treatment was stopped for ten days.

Animals↗
PubMed1998

Differential effects of thiocyanate on the binding thermodynamics of bicuculline methiodide versus SR95531 (gabazine) to the gamma-aminobutyric acid receptor-ionophore complex.

The temperature dependence of the binding of [3H]SR 95531 (Gabazine), an antagonist of gamma-aminobutyric acid (GABA(A)) receptors, was studied in synaptosomal membranes of rat brain in the presence of 50 mM KSCN. The displacing potencies of the antagonists bicuculline methiodide and Gabazine were determined at five temperatures between 0 degrees and 37 degrees. Van't Hoff plots of the displacing potencies were analyzed by linear regression in the presence and absence of thiocyanate. Thiocyanate hardly affected the exothermic ionic binding interaction of gabazine. In contrast, thiocyanate strongly potentiated the binding of bicuculline methiodide and deprived it of its exothermic nature. The enhanced binding of bicuculline methiodide in the presence of chaotropic SCN- ions might be reconciled with "entropic trapping" in a sterically constrained hydrophobic binding pocket.

Animals↗
PubMed1980

Determination of cyanide and thiocyanate in biological fluids by gas chromatography-mass spectrometry.

A sensitive, specific and accurate method is described for the determination of cyanide and thiocyanate in biological fluids. Potassium cyanide containing 95% 15N is added to the sample as internal standard and both endogenous cyanide and standard are separated by gas-phase diffusion into sodium hydroxide solution. Cyanogen chloride is prepared by reaction with sodium p-toluenesulphonchloramide and extracted into n-heptane. Quantitative analysis is carried out by gas chromatography-mass spectrometry (GC-MS) with selective ion monitoring of the molecular ions at m/e 61and m/e 62. Thiocyanate levels are determined by a similar procedure in which 15N-labelled sodium thiocyanate is used as internal standard. The method is applicable to a wide range of biological samples and is free from interference by other sample components.

Cyanides↗
PubMed1999

Determination of platinum (II,IV) and palladium(II) as thiocyanate complexes by capillary zone electrophoresis analysis of carboplatin and similar drugs.

The thiocyanate complexes of Pd(II), Pt(II) and Pt(IV) were studied by capillary zone electrophoresis. Pd(II) can be detected in the form of the thiocyanate complex at 305 nm with higher sensitivity than in the form of its chloro complex (absorption maximum 214 nm). A detection limit equal to 5 ppb for Pd has been finally achieved. The possibility of simultaneous determination of Pd(II) and Pt(IV) in the form of thiocyanate complexes has also been demonstrated. When the method optimized for the determination of Pt(II) was applied to the drugs Cykloplatin and Ribocarbo (containing carboplatin) and Platidiam (containing cisplatin), good agreement of the platinum content with the declared value was obtained. Samples of vehicle exhaust particulates (National Institute for Environmental Studies, Japan, No. 8 reference material) were also analyzed.

Antineoplastic Agents↗
PubMed1998

Simultaneous determination of cyanide and thiocyanate in blood by ion chromatography with fluorescence and ultraviolet detection.

An ion chromatographic method for the simultaneous determination of cyanide and thiocyanate in blood has been developed. After extraction by adding water and methanol to blood, cyanide was derivatized with 2,3-naphthalenedialdehyde and taurine to give a fluorescent product of 1-cyanobenz[f]isoindole. This compound was detected with high sensitivity by fluorometry and the underivatized thiocyanate was detected by ultraviolet absorption. The detection limits were 3.8 pmol ml(-1) for cyanide and 86 pmol ml(-1) for thiocyanate, and the recoveries from blood were ca. 83% and ca. 100%, respectively. The proposed method was successfully applied to the analysis of both anions in blood from smokers, non-smokers and fire victims.

Chromatography, Ion Exchange↗
PubMed1977

Effect of thiocyanate on mammary gland growth in rats.

In growing rats from 3 weeks to 3 months old, 0.1% potassium thiocyanate (KSCN) decreased the plasma protein-bound iodine level by 47% and the total DNA in the mammary gland by 11%, but had no effect on the total RNA. Administration of thiocyanate in the form of 0.1, 0.3 and 0.5% KSCN during pregnancy and 14 d of lactation lowered the protein-bound iodine level by 48-66%, the total DNA by 11-47% and the total RNA by 14-63%, depending on the KSCN dosage. The 14-d-old litters of rats receiving thiocyanate weighed 4-41% less than those in the control group.

Animals↗
PubMed1993

Spectroscopic characterization of the interaction of azide and thiocyanate with the binuclear center of cytochrome oxidase: evidence for multiple ligand sites.

The interactions of azide and thiocyanate with the binuclear center of oxidized cytochrome c oxidase have been characterized by Fourier transform infrared and UV-vis spectroscopy, electron paramagnetic resonance and magnetic and natural circular dichroism. Azide binds in two phases, a high-affinity phase (Kd = 64 microM) in which it is bound as a bridge to the binuclear center and a low-affinity phase (Kd = 20 mM) in which it displaces one of the axial ligands to cytochrome a. Thiocyanate also binds in two phases. The high-affinity phase (Kd = 2.7 mM) involves binding in a terminal mode to CuB; the low-affinity phase is complex and involves both CuA and cytochrome a. In contrast to the recent proposal of Yoshikawa and Caughey [(1990) J. Biol. Chem. 265, 7945-7958], we conclude that cyanide also functions as a bridge between cytochrome a3 and CuB. In the presence of cyanide, azide does not bind to its high-affinity site but thiocyanate does bind to its high-affinity site.

Azides↗
PubMed1998

Reaction of myeloperoxidase compound I with chloride, bromide, iodide, and thiocyanate.

Myeloperoxidase plays a fundamental role in oxidant production by neutrophils. The enzyme uses hydrogen peroxide to oxidize chloride (Cl-), bromide (Br-), iodide (I-), and the pseudohalide thiocyanate (SCN-) to their respective hypohalous acids. This study for the first time presents transient kinetic measurements of the oxidation of these halides and thiocyanate by the myeloperoxidase intermediate compound I, using the sequential mixing stopped-flow technique. At pH 7 and 15 degrees C, the two-electron reduction of compound I to the native enzyme by Cl- has a second-order rate constant of (2.5 +/- 0.3) x 10(4) M(-1) s(-1), whereas reduction of compound I by SCN- has a second-order rate constant of (9.6 +/- 0.5) x 10(6) M(-1) s(-1). Iodide [(7.2 +/- 0.7) x 10(6) M(-1) s(-1)] is shown to be a better electron donor for compound I than Br- [(1.1 +/- 0.1) x 10(6) M(-1) s(-1)]. The pH dependence studies suggest that compound I reduction by (pseudo-)halides is controlled by a residue with a pKa of about 4.6. The protonation of this group is necessary for optimum (pseudo-)halide anion oxidation. These transient kinetic results are underlined by steady-state spectral and kinetic investigations. SCN- is shown to be most effective in shifting the system myeloperoxidase/hydrogen peroxide from the peroxidatic cycle to the halogenation cycle, whereas iodide is shown to be more effective than bromide which in turn is much more effective than chloride. Decreasing pH increases the rate of this transition. Our results show that thiocyanate is an important substrate of myeloperoxidase in most environments and that hypothiocyanate is likely to contribute to leukocyte antimicrobial activity.

Anions↗
PubMed2002

2-Trimethylsilylethyl sulfides in the von Braun cyanogen bromide reaction: selective preparation of thiocyanates and application to nucleoside chemistry.

Mixed 2-(trimethylsilyl)ethyl sulfides were synthesized and used in the von Braun cyanogen bromide reaction for preparing selectively thiocyanates in high yield. We show here that this cleavage reaction is highly selective in methanol in comparison with the reaction of the corresponding non-silyl sulfide analogues. This reaction was applied to the synthesis of nucleosidic thiocyanates such as the new nucleosides 14 and 18 in the search for mechanism-based inhibitors of ribonucleoside diphosphate reductase and bioactive molecules. The selective cleavage is possible for sulfides bearing hydroxyl functions and aromatic rings. The reactions of cyanogen bromide as cyanating and brominating agent were observed for the first time under the same conditions with the naphthoxyhexyl 2-trimethylsilylethyl sulfide 7, which, treated with cyanogen bromide in dichloromethane, led selectively to the p-bromonaphthoxyhexyl thiocyanate 10 in 89% yield. Another reaction induced by cyanogen bromide was observed in dichloromethane with the 2-(trimethylsilylethyl)thio nucleoside 13, which gives the corresponding symmetrical disulfide 21 in good yield.

Bromine↗
PubMed2003

Isolation and identification of thiocyanate utilizing chemolithotrophs from gold mine soils.

A mixed bacterial culture capable of growing in potassium-thiocyanate containing medium (200 mg KSCN) has been isolated from bacterial suspensions of soil samples collected near gold mines in Kumjung (Korea). The isolates were initially characterized by metabolic profile analysis and were identified as Bacillus thermoglucosidasius, Bacillus cereus, Bacillus licheniformis, Bacillus mycoides, Brevibacterium epidermidis, Brevibacterium otitidis, and Corynebacterium nitrilophilus. One of the seven isolates was initially characterized as Brevibacterium epidermidis, which is not known to degrade thiocyanate. However, using 16S rDNA sequencing, this strain was identified as a member of Klebsiella. The strain shows high similarity values (95.8 to 96.4%) with Klebsiella species, and the closest known relative was found to be K. ornithinolytica ATCC 31898. The result indicates that species of the genus Klebsiella were the closest phylogenetic relatives of the investigated strain. This is the first known report of a member of Klebsiella that is capable of utilizing thiocyanate as sole source of carbon and nitrogen.

Bacillus↗
PubMed1966

The inhibition of streptococci by lactoperoxidase, thiocyanate and hydrogen peroxide. The effect of the inhibitory system on susceptible and resistant strains of group N streptococci.

1. The growth of the lactoperoxidase-sensitive Streptococcus cremoris 972 in a synthetic medium was inhibited by lactoperoxidase and thiocyanate. The glycolysis and oxygen uptake of suspensions of Strep. cremoris 972 in glucose or lactose were also inhibited. The lactoperoxidase-resistant Strep. cremoris 803 was not inhibited under these conditions but was inhibited in the absence of a source of energy. 2. Lactoperoxidase (EC 1.11.1.7), thiocyanate and hydrogen peroxide completely inhibited the hexokinases of non-metabolizing suspensions of both strains. The inhibition was reversible, hexokinase and glycolytic activities of Strep. cremoris 972 being restored by washing the cells free from inhibitor. The aldolase and 6-phosphogluconate-dehydrogenase activities of Strep. cremoris 972 were partially inhibited but several other enzymes were unaffected. 3. The resistance of Strep. cremoris 803 to inhibition was not due to the lack of hydrogen peroxide formation, to the destruction of peroxide, to the inactivation of lactoperoxidase or to the operation of alternative pathways of carbohydrate metabolism. 4. A ;reversal factor', which was partially purified from extracts of Strep. cremoris 803, reversed the inhibition of glycolysis of Strep. cremoris 972. The ;reversal factor' also catalysed the oxidation of NADH(2) in the presence of an intermediate oxidation product of thiocyanate and was therefore termed the NADH(2)-oxidizing enzyme. 5. The NADH(2)-oxidizing enzyme was present in lactoperoxidase-resistant streptococci but was absent from lactoperoxidase-sensitive streptococci.

Carbohydrate Metabolism↗
PubMed2003

Residual goitre in the postiodization phase: iodine status, thiocyanate exposure and autoimmunity.

OBJECTIVE: This study was done to assess goitre prevalence, thyroid functional status and cause of residual goitre among school children in the postsalt iodization phase in India. DESIGN: A cross-sectional study in which, 14762 school children in the age group of 6-18 years, from different States and Union territories of India, were evaluated for goitre prevalence, urinary iodine and thiocyanate excretion, functional status of the thyroid as well as serological and cytopathological markers for thyroid autoimmunity. MEASUREMENTS: Urinary iodine (wet ashing method), urinary thiocyanate (colourimetric method), serum thyroxine [in-house radioimmunoassay (RIA)], serum TSH (IRMA), antithyroid microsomal and antithyroglobulin antibodies (haemagglutination method) were estimated. Fine-needle aspiration cytology was performed in all goitrous subjects giving consent. RESULTS: The overall goitre prevalence was 23% (27.1% girls; 17.8% boys, P < 0.001). Subjects belonging to poor socio-economic strata had significantly higher goitre prevalence. Median urinary iodine excretion (UIE) in goitrous subjects (2-53 micromol/l) was significantly higher than in controls (2-24 micromol/l; P < 0.001). Levels of UIE observed among goitrous subjects showed no relationship with the presence or absence of thyroid dysfunction or with thyroid antibody status. High titres (> or = 1:1600) of TMA were present more often in goitrous subjects (6.08%) than nongoitrous controls (0.34%; P < 0.001) and in girls (7.3%) than boys (2.35%; P < 0.001). TMA positivity were significantly more among goitrous subjects with thyroid dysfunction than in euthyroid subjects. Significantly higher median urinary thiocyanate (USCN) excretion was observed in goitrous subjects (0.75 mg/dl) compared to controls (0.64 mg/dl; P < 0.001) and goitrous girls compared to goitrous boys. USCN excretion of goitrous subjects and controls showed no relationship with functional or thyroid antibody status in various groups. CONCLUSIONS: Persistent, albeit reduced prevalence of goitre, despite adequate iodine prophylaxis, suggests existence of additional factors in goitrogenesis in India. Thyroid autoimmunity can explain only a part of the goitre prevalence. The role of goitrogens in residual goitre prevalence is brought forth.

Adolescent↗
PubMed2004

Combination of cassava flour cyanide and urinary thiocyanate measurements of school children in Mozambique.

The maximum daily cassava flour intake of children may be calculated from determination of the total cyanide content of cassava flour and urinary thiocyanate levels of school children in samples collected at the same time and place. Four sites, two with and two without recent konzo cases, were chosen for study. In two sites with recent konzo cases, 84% and 93% of school children consumed cassava the previous day, and the calculated maximum daily consumption of cassava was over 700 g. In two sites without recent konzo cases, about 50% of school children consumed cassava the previous day and the calculated daily consumption of cassava flour was less than 150 g. By measurements of cyanide in flour and urinary thiocyanate we are therefore able to distinguish between communities whose diet is almost totally reliant on cassava, and who are therefore susceptible to konzo, and those who have a broader diet and are free from konzo. In another calculation it is shown that 4-23% of the essential S-containing amino acids in the cassava flour consumed by children is used up to detoxify and flour cyanide to thiocyanate. This depletion of methionine and cystine may leads to protein deficiency and may contribute to onset of konzo.

Child↗
PubMedDate not supplied

Effect of linamarin on thiocyanate production and thyroid activity in rats.

The principal cyanogenic glucoside in cassava is linamarin (2-hydroxyisobutyronitrile-beta-D-glucoside). Addition of pure linamarin to a diet based on 10% vitamin-free casein did not affect the weight gain of rats. However, as expected, the animals that received the casein diet supplemented with methionine gained more weight than those that received the unsupplemented diet. The amount of thiocyanate ion excreted in the urine by the animals that received linamarin was higher than that excreted by the animals that did not receive linamarin at both levels of dietary methionine. The plasma thiocyanate concentration was also higher for linamarin-fed animals than for animals that did not receive linamarin. Higher plasma thiocyanate levels were associated with a lower percentage uptake of radioiodine by the thyroid.

Animals↗
PubMedDate not supplied

Estimating the hazards of less hazardous cigarettes. II. Study of cigarette yields of nicotine, carbon monoxide, and hydrogen cyanide in relation to levels of cotinine, carboxyhemoglobin, and thiocyanate in smokers.

Yields of chemical constituents such as tar, nicotine, CO, and HCN defined by smoking machines are commonly assumed to provide a reasonable indication of the relative hazard associated with smoking a given brand of cigarette. Results reported here suggest that this assumption should be carefully reexamined. A total of 240 subjects, representing a wide range of smoking and brand characteristics, were recruited for an investigation of possible relations between brand yields and exposure (levels of carboxyhemoglobin, breath CO, plasma cotinine, plasma thiocyanate, and saliva thiocyanate). Exposure was highly correlated with consumption (number of cigarettes per day), but their was no correlation between any estimate of exposure and brand yield when level of consumption was held constant. In addition, a comparison of levels of carboxyhemoglobin and plasma thiocyanate for 16 smokers of "low-hazard" and 15 smokers of "high-hazard" cigarette brands revealed little difference between the two groups, even though average cigarette yields differed as much as 2- to 3-fold. A possible explanation for the results may be that current values for average puff volume, duration, and interval differ significantly from those used in programming smoking machines, particularly in the case of brands with low nicotine delivery.

Absorption↗
PubMed1984

Haloacetonitrile excretion as thiocyanate and inhibition of dimethylnitrosamine demethylase: a proposed metabolic scheme.

Haloacetonitriles, contaminants present in chlorinated drinking water, were administered orally to rats, and the urinary excretion of thiocyanate was measured as an index of cyanide release. The urinary excretion of thiocyanate accounted for 14.2% of the dose of monochloroacetonitrile; 7.7-12.8% of the dose of bromochloro-, dichloro-, and dibromoacetonitrile; and 2.25% of the dose of trichloroacetonitrile. The haloacetonitriles inhibited rat-liver microsomal dimethylnitrosamine (DMN) demethylase in an in vitro assay system. Dibromo- and bromochloroacetonitrile were the most potent inhibitors of DMN demethylase, with Ki = 3-4 X 10(-5) M; dichloro- and trichloroacetonitrile were the next most potent, with Ki = 2 X 10(-4) M; and monochloroacetonitrile was the least potent inhibitor, with Ki = 9 X 10(-2) M. Trichloroacetonitrile, but not dibromoacetonitrile, when administered orally inhibited hepatic DMN demethylase activity. The relative capacity of the haloacetonitriles to inhibit DMN demethylase and to be excreted as thiocyanate did not correlate.

Acetonitriles↗
PubMed2002

Thiocyanate in food and iodine in milk: from domestic animal feeding to improved understanding of cretinism.

Transport of iodine in the mammary gland into breast milk plays a central role in various fields of prevention of thyroid diseases. First, a sufficient content of iodine in the mother's milk is necessary for normal brain development in the breastfed child. This is attained by expression during lactation in the mammary gland of the sodium iodide symporter (NIS), also responsible for iodine transport in the thyroid. Milk iodine content varies with the iodine intake of the mother, and urinary iodine excretion in groups of mothers seems to be a valuable indicator of the iodine status of their breastfed children. Second, iodine in dairy products provides a considerable part of iodine intake in many populations. Thiocyanate from rapeseed feeding of cows decreases milk iodine content, probably by competitive inhibition of NIS in the mammary gland. Alterations in feeding of dairy cows may alter the iodine content of consumer milk, and this may influence the risk of thyroid diseases in the population. Thiocyanate inhibition of iodine transport into milk may also be operative in humans with a high thiocyanate intake. This could further impair iodine status in breastfed children in low-iodine intake areas of the world. It can be speculated that a low-iodine content of mother's milk because of inhibition of NIS in the mammary gland may be one factor of importance for development of myxedematous cretinism.

Animal Feed↗
PubMedDate not supplied

A colourimetric procedure for the determination of thiocyanate in plasma.

A colourimetric method is described for the determination of thiocyanate using a modification of the König reaction. The reagents used are stable, relatively non-toxic, and produce a colour with lambda max 543 nm which is stable for at least 90 minutes after formation. Although the method requires only 0.1--0.5 mL of plasma, 0.25 mg/L of thiocyanate may be determined using this procedure. The calibration curve is linear to at least 60 mg/L and is highly reproducible. Plasma samples analysed on a within-day (10.0 mg/L) and between-day (4.9 mg/L) basis, had coefficients of variation (CV) of 2.39% and 3.09%, respectively. Recovery of thiocyanate added to plasma is quantitative.

Colorimetry↗