[Formation of phenyl thiocyanate and phenyl isothiocyanate in the reaction of benzenediazonium sulfate, cupric ion and thiocyanate ion (author's transl)].
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Copper↗
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[Effect of thiocyanate administration on milk and plasma iodine as well as thiocyanate level].
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Animals↗
Examination of antithyroid effects of smoking products in cultured thyroid follicles: only thiocyanate is a potent antithyroid agent.
We studied the antithyroid action of cigarette smoking products (nicotine, cotinine, and thiocyanate) in the physiological culture system of porcine thyroid follicles. Iodide uptake, iodine organification, de novo thyroid hormone formation, and iodide efflux were measured in the presence of 0-200 mumol/l nicotine, cotinine, or potassium thiocyanate. Nicotine and cotinine did not inhibit iodide transport or thyroid hormone formation. Thiocyanate concentrations equivalent to serum levels of smokers showed three independent antithyroid actions: (i) inhibition of iodide transport, (ii) inhibition of iodine organification, and (iii) increased iodide efflux. Inhibition of iodide transport by thiocyanate was competitive with iodide and independent of TSH concentration. Thiocyanate did not inhibit TSH mediated cAMP production or Na+K+ ATPase activity, a sodium pump for iodide transport. When 50 mumol/l thiocyanate was added 2 h after incubation with iodide or when 1 mumol/l thiocyanate was added from the beginning of incubation, iodine organification was inhibited without changing iodide transport. De novo thyroid hormone formation was clearly inhibited by 50 mumol/l thiocyanate. Thiocyanate increased iodide efflux although the degrees of iodide efflux by 10 mumol/l and 100 mumol/l thiocyanate did not differ significantly. In summary, thiocyanate, a product of smoking, has three independent antithyroid activities. The data of iodide transport kinetics suggest that thiocyanate can be an antithyroid agent particularly in iodine deficiency.
Animals↗
Kinetics of elimination of thiocyanate in 7 healthy subjects and in 8 subjects with renal failure.
The concentration of thiocyanate in the serum of eight test subjects with renal failure and seven healthy control subjects was measured, as it declined with time, after oral doses of thiocyanate or i.v. injections of nitroprusside had been administered. Additional measurements were taken, on the healthy subjects only, of the concentrations of thiocyanate in the urine, and also of the influence of an increased chloride intake on the rate of elimination of thiocyanate. For the healthy subjects an elimination half-life of between one and five days (mean c. 3 days) was found. Increasing the chloride elimination rate to approximately twice normal did not significantly speed up the rate of thiocyanate elimination. The amounts of thiocyanate which had been administered as doses reappeared almost exclusively in the urine. For the subjects with renal failure, the elimination half-life had a mean value of approximately nine days. The elimination constants were found to be proportional to the creatinine-clearance rates. The ke value at a creatinine-clearance of zero ml/min was approximately 15% of the ke value at a creatinine-clearance rate of 120 ml/min. The distribution volumes for thiocyanate were greater for the patients with renal failure than for the healthy subjects. The conclusions for therapies using nitroprusside are discussed.
Adult↗
Effect of thiocyanate on nitrite estimation and the cleavage of nitrosamines.
Thiocyanate or bromide increased the colour formed by nitrite reacting with sulfanilic acid and naphthylethylenediamine. If the colour reagents were added together with thiocyanate (final concentration, M/10), the colour intensity was doubled. If sulfanilic acid was added three minutes before addition of naphthylethylenediamine, the relationship between nitrite concentration and colour production was more linear in the presence of thiocyanate. This effect was due to thiocyanate catalysing the diazotization of sulfanilic acid and inhibiting the reaction of nitrite with naphthylethylenediamine. Bromide and thiocyanate are similar in their catalytic effects on nitrosation, and hydrobromic acid in glacial acetic acid is an effective reagent for denitrosation of nitrosamine. Although thiocyanate catalysed denitrosation of nitrosamines, the effect was small except with nitrosomethylaniline, which had also been found to be denitrosated by sulfanilic acid. Thiocyanate could not be used generally for the destruction of nitrosamines; it was also found to be ineffective as an alternative to hydrobromic acid in the estimation of nitrosamines.
Acetates↗
Smoking during pregnancy--effects on the fetus and on thiocyanate levels in mother and baby.
Twenty-eight mothers smoking 10--20 cigarettes daily during pregnancy had significantly higher serum thiocyanate concentrations at delivery compared in 25 non-smoking controls. The thiocyanate levels were positively correlated to cigarette consumption and inversely correlated to the birth weights of the infants. A highly significant correlation existed between serum thiocyanate levels of the mother and umbilical cord serum thiocyanate levels, reflecting a nearly complete equilibration. The thiocyanate concentrations in human milk on the 4th day after delivery were considerably lower than the serum concentrations, and no correlation existed between serum and milk concentrations. The infants of smoking mothers had significantly decreased weight and length at birth compared in infants of non-smokers. Birth weights were 3 344 +/- 434 g and 3 620 +/- 504 g respectively (p less than 0.05), and lengths 49.8 +/- 1.7 cm and 51 +/- 1.6 cm respectively (p less than 0.05). No differences were found between smokers and non-smokers in placental and umbilical cord histology, and umbilical cord artery medial area. It is concluded that serum thiocyanate concentration in smokers may be used as an objective measure for smoke exposure, and that maternal cigarette smoking acts as an exogenous factor which interferes with intrauterine development of the fetus in a dose related way.
Birth Weight↗
Thiocyanate ion formation in rapeseed meals.
Meal prepared from unheated rapeseed (Brassica napus cv. Zephyr) showed the presence of t,iocyanate ion, while meal from heated seed of the same cultivar did not show detectable amounts. Unheated seed meal on autolysis, and heated seed meal on incubation with thioglucosidase, yielded increased amounts of thiocyanate ion. Various commercial rapeseed meals showed the presence of t,iocyanate ion only after enzyme incubation. Low glucosinolate, cv. Bronowski, and higher glucosinolate, cv. Zephyr on enzymic incubation yielded comparable amounts of thiocyanate ion, suggesting that the precursor responsible in the two varieties was the same and present in similar quantities. No formation of thiocyanate ion was observed on incubation of sinigrin with thioglucosidase. Rats dosed with heated meal, containing intact glucosinolate, showed a slight increase of thiocyanate ion in the urine as compared with control rats dosed with water, while a relatively large increase followed dosing with sinigrin. Rats dosed with meal containing free thiocyanate ion excreted the ingested thiocyanate ion almost quantitatively.
Animal Feed↗
Method for determining thiocyanate in serum and urine.
We describe a method for rapid and specific measurement of thiocyanate in serum or urine. We separate thiocyanate from interfering compounds by adsorbing it on an anion-exchange resin that has special affinity for thiocyanate, then eluting with sodium perchlorate. The eluted thiocyanate is quantified by a modified König reaction, sodium hypochlorite being used as the chlorinating reagent. Analytical recovery of thiocyanate added to serum and urine was quantitative; the coefficient of variation was 2.3% for both within-day and between-day precision. Cyanide and certain antibiotics interfere, but may be eliminated by including additional washing steps in the usual procedure. The proposed procedure was compared with another method, based on the oxidation of thiocyanate to cyanide. Agreement was satisfactory, both for serum and urine.
Chromatography, Ion Exchange↗
Effect of cyanide antidotes on the metabolic conversion of cyanide to thiocyanate.
The excretion of thiocyanate following the administration of equitoxic doses of cyanide to unprotected mice and to animals pretreated with various cyanide antidotes has been studied. The results demonstrate that cyanide given alone or to animals pretreated with thiosulfate is extensively converted to thiocyanate. Animals pretreated with sodium nitrite or a combination of nitrite and sodium thiosulfate excreted even higher amounts of thiocyanate. This demonstrates that cyanide originally detoxified by combination with methemoglobin is ultimately converted to thiocyanate in the animal body. Pretreatment of animals with cobalt compounds (cobaltous chloride or dicobalt-EDTA) or a combination of cobalt compounds and thiosulfate resulted, on the other hand, in a less efficient conversion of cyanide to thiocyanate. The cyanide detoxified by trapping as highly undissociated cobalt-cyanide complexes is instead excreted in the urine, as demonstrated by detection of high amounts of cobalt ions and strongly complex-bound cyanide in the urine from animals treated with cobalt compounds and cyanide. A method for the determination of cyanide present as cobalt-cyanide complexes is described and its forensic application is proposed.
Animals↗
Determination of thiocyanate in human saliva and urine by ion chromatography.
A simple ion-chromatographic method has been developed for the determination of trace amounts of thiocyanate in human saliva and urine. Thiocyanate separation and detection were carried out on an ODS column coated with cetyldimethylamine and by an ultraviolet detector, respectively. Citrate solution (1 mmol l-1) was used as the mobile phase. Thiocyanate was clearly separated from many organic and inorganic anions found in saliva and urine samples. The analytical results obtained by the proposed method agreed with those of the Fe(3+)-thiocyanate spectrophotometric method. Thiocyanate concentrations in the saliva and urine of smokers were found to be significantly higher than those of non-smokers.
Chromatography, Ion Exchange↗
Effects of prolonged cyanide and thiocyanate feeding in rats.
Male weaning rats were fed a semipurified diet containing 10% casein; this diet restricted in methionine, vitamin B12, and iodine; or the complete and restricted diets supplemented with either 1500 ppm potassium cyanide or 2240 ppm potassium thiocyanate for 11.5 mo. There were no deaths or clinical signs of toxicity. Cyanide, but not thiocyanate, caused a consistent reduction in weight gain in the complete and restricted groups. Both cyanide and thiocyanate caused decreased thyroid gland activity in young rats, particularly in the restricted groups. Plasma thyroxine concentrations were maintained in the mature cyanide-treated rats, even though secretion rates were decreased. However, the mature thiocyanate-treated animals showed decreased plasma thyroxine concentrations, despite thyroid gland enlargement. Modest primary myelin degeneration in the spinal cord white matter was found in the restricted group and in rats receiving this diet supplemented with either cyanide or thiocyanate. The lesions did not resemble those of a vitamin B12 deficiency in appearance or those of acute cyanide intoxication in distribution. Because of tissue autolysis, it could not be determined whether these changes resulted from histotoxic anoxia or an alteration of oligodendroglial myelin metabolism.
Animals↗
Chronic administration of cyanide: urinary excretion of thiocyanate in male and female rats.
The urinary elimination of thiocyanate was investigated in male and female rats following the chronic administration of potassium cyanide. Female rats dosed at the level of 5 mg KCN/kg once a week and twice a week respectively, displayed no significant difference in the excretion of thiocyanate in urine after periods of up to eight weeks of study. Similarly, male rats that were administered 5 mg/KCN/kg twice weekly showed no significant difference in the amount of thiocyanate excreted. The elimination patterns of thiocyanate in male and female rats showed no significant differences. The results suggest that a substrate saturation phenomenon is not operative with cyanide metabolism at the dosage level of potassium cyanide employed in this study. This is contrary to a previously published study which reported that the urinary excretion of thiocyanate decreased after chronic potassium cyanide administration.
Animals↗
Nitrite and thiocyanate in the fasting and secreting stomach and in saliva.
The concentrations of nitrite and thiocyanate in fasting and pentagastrin stimulated gastric juice and in saliva have been examined. Nitrite was found in all of 17 samples of fasting gastric juice, mean 4-9 +/- 1-1 muM. Stimulation of gastric secretion with pentagastrin caused no significant change in nitrite concentration. Thiocyanate was detected in all of 21 samples of fasting gastric juice and the difference in concentration between smokers and non-smokers probably reflects similar differences in saliva. In contrast to the nitrite data there was a significant drop in thiocyanate concentration of gastric juice after pentagastrin from 0-9 +/- 0-1 mM to 0-3 +/- 0-04 mM, suggesting a salivary origin for the thiocyanate in gastric juice. Thiocyanate is a powerful catalyst of nitrosation, which, together with small amounts of nitrite and naturally occurring amines could lead to the intragastric formation of carcinogenic nitrosamines and in certain circumstances be a factor in the aetiology of gastric cancer.
Fasting↗
Characteristics of Thiobacillus thioparus and its thiocyanate assimilation.
Thiocyanate-assimilatig bacterium, TK 21, was isolated from activated sludge used for the treatment of thiocyanate contained in coke-oven liquor. This organism oxidized thiosulfate and elemental sulfur, causing a decrease of pH of the medium. These facts indicated that it belongs to the genus Thiobacillus. Potassium thiocyanate (0.5 g/l) was completely assimilated during 60 h. Thiosulfate inhibited the assimilation of thiocyanate but elemental sulfur did not. This bacterium did not evolve cyanide as its oxidation product after the decomposition of thiocyanate. The isoalted bacterium was identified as Thiobacillus thioparus. Examination of the composition of cellular fatty acid of three strains of T. thioparus showed that they prossessed 3-hydroxy fatty acid of C10 and C12; saturated straight chains of C10, C12, C15, C16, C17, and C18; monounsaturated straight chains of C16 and C18; and cyclopropane acid of C17.
Fatty Acids↗
Thiocyanate inhibition of ATPase and its relationship to anion transport.
Adenosine triphosphatase activity not dependent on sodium or potassium but inhibited by thiocyanate is present in broken-cell homogenates of eel gill and rat kidney. This enzymatic property is predominantly associated with mitochondria, although thiocyanate-inhibited ATPase can also be detected in microsomes with little or no mitochondrial contamination as measured by the activity of the mitochondrial marker enzyme succinic dehydrogenase. When eels are transferred from fresh to salf water, thus increasing active outward transport of chloride across the gill, the thiocyanate-inhibited ATPase of gill microsomes does not change, though the activities of succinic dehydrogenase and Na-K-ATPase in gill homogenates are augmented. The thiocyanate-inhibited ATPase of homogenates of outer renal medulla does not differ from that of renal cortex, in contrast to Na-k-atpase which is higher in renal medulla than in cortex. The data do not support a role for thiocyanate-inhibited ATPase in active chloride transport by epithelial tissues.
Adenosine Triphosphatases↗
Effect of thyroid status and thiocyanate on absorption and excretion of iodine by cattle.
Effects of throidectomy or iodine-131, thyroprotein feeding, and thiocyanate dosing on radioiodine metabolism in the bovine were studied in 34 animals. Two thyroidectomized calves excreted 44% more radioiodine in urine and 38% less in feces than two thyroid-tact calves. Oral thiocyanate increased urinary radioiodine 32% in throidectomized and 46% in intact calves while reducing fecal radioiodine 48% in throidectomize and 11% in intact calves. Urninary radioiodine clearance of two heifers was increased 52% by thiocyanate, but urine flow was not affected. Percentages of radioiodine doses cycled through the abomasum daily and recovered from digestive tracts at slaughter, respectively, were: 12 thyroid-intact cows, 468 and 77; two intact cows fed 10 g sodium thiocyanate daily,64 and 41; 10 thyroid-damagedcows, 506 and 149; and four thyroid-damaged cows fed 8 g thyroprotein daily, 372 and 93. Thyroid damage had little effect on gastric radioiodine secretion but increased total digestive tract radioiodine because of greater volume of tract contents. Inhibition of gastric radioiodine secretion by thiocyanate reduced the digestive tract radioiodine pool. The digestive tract iodine pool may conserve iodine by reducing loss in urine.
Abomasum↗
Determination of thiocyanate in tissues and body fluids of animals by gas chromatography with electron-capture detection.
A method for the quantitative extraction of thiocyanate from biological material has been developed. Levels of 0.2-5 ppm of thiocyanate, in the presence of cyanide, were determined by gas-solid chromatography using 2-bromopropane as internal standard. Reliable results can be obtained only after careful deproteinization of the extracts with hot methanol. Cyanide can be eliminated by reaction with alkaline formaldehyde. The reproducibility of the determination of thiocyanate in biological extracts was +/-5%; the recoveries were over 90%. In vivo experiments with KS14CN-treated rats gave good agreement between the analytical results and the amount of thiocyanate determined by isotope dilution.
Animals↗
Use of thiocyanic acid to form 2-thiohydantoins at the carboxyl terminus of proteins.
The chemistry of the formation of 2-thiohydantoins on the carboxyl terminal of peptides or proteins was investigated. It was found that thiocyanic acid was much more reactive for the formation of 2-thiohydantoins than were the thiocyanate salts. The physical reasons for this observation are explained. The kinetics of the reaction of a number of proteins, and some of their fragments, with thiocyanic acid were also determined. Simple and safe procedures for the preparation of anhydrous thiocyanic acid solutions were devised. The prospective application of these procedures to sequencing from the carboxyl terminal of a polypeptide is discussed.
Amines↗