PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “CYANIDES”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1999

Effects of ultrasound on the formation of alpha-benzoylbenzyl cyanide from benzyl cyanide and alkylphenyl ketone from alpha-alkylbenzyl cyanide by potassium superoxide in the presence of crown ether.

Ultrasound accelerates the formation of alpha-benzoylbenzyl cyanide and benzoic acid in the reaction of benzyl cyanide with potassium superoxide in the presence of 18-crown-6. Similarly, 4-methylbenzyl cyanide, 4-methoxybenzyl cyanide and 4-chlorobenzyl cyanide gave the corresponding alpha-(4-methylbenzoyl)-4-methylbenzyl cyanide, alpha-(4-methoxybenzoyl)-4-methoxybenzyl cyanide and alpha-(4-chlorobenzoyl)-4-chlorobenzyl cyanide in 25-43% isolated yields under the same reaction conditions. Benzoic, p-toluic, 4-methoxybenzoic and 4-chlorobenzoic acids were also formed in these reactions. No reaction was observed when the mixture was simply stirred. Reflux instead of sonication gave lower yields of the products. However, alpha-alkylbenzyl cyanide produced a high yield of the phenylalkyl ketones when stirred. Interestingly, the corresponding benzoic acid was not formed in these reactions. Possible mechanisms for the formation of alpha-benzoylbenzyl cyanide from benzyl cyanide and phenylalkyl ketones from alpha-alkylbenzyl cyanide are also proposed.

Journal Article↗
PubMed1988

Cyanide distribution in five fatal cyanide poisonings and the effect of storage conditions on cyanide concentration in tissue.

The cyanide distribution in five fatal cyanide poisonings was analyzed by the pyridine-pyrazolone method using a Conway diffusion cell. In order to study the effect of storage conditions on cyanide concentration in tissue samples, the cyanide concentrations were first measured immediately after collection of the samples at autopsy, then measured again after storage in a refrigerator (4 degrees C) or in a freezer (-20 degrees C) for periods ranging from 1 day to 3 weeks. Concentrations in all but three of the blood samples stored at 4 degrees C or -20 degrees C increased, with concentration ratios based on measurement made before and after storage ranging from 0.71 to 1.46. The concentrations in the liver, kidney, and brain samples either increased or decreased, with ratios of from 0.2 to 8.8. The concentrations in the stomach contents samples decreased rapidly at 4 degrees C, but hardly changed at all at -20 degrees C.

Adult↗
PubMed1997

Hydrogen cyanide generation by mu-opiate receptor activation: possible neuromodulatory role of endogenous cyanide.

Hydrogen cyanide, a gaseous molecule, is produced by white blood cells during phagocytosis. The present study examined the possibility that neuronal-like cells may also produce cyanide following activation. Rat pheochromocytoma (PC12) cells exhibited a low level of cyanide generation that was significantly increased by mu-opiate agonists (hydromorphone, morphine) and blocked by naloxone. A variety of other agonists including bradykinin, nicotine and glutamate did not generate cyanide in PC12 cells. Systemic administration of hydromorphone to rats increased brain cyanide levels by 61% after 15 min. Using microdialysis probes implanted in the cortical-hippocampal areas of the anesthetized rat or in the hypothalamus of the conscious hamster, a 2- to 5-fold increase in cyanide generation was seen after hydromorphone administration and this increase was blocked by naloxone. To determine whether cyanide release by hydromorphone has functional significance in a neuronal system, cyanide enhancement of N-methyl-D-aspartate (NMDA)-induced increased [Ca2+]i was measured in rat cerebellar granule cells. Hydromorphone enhanced the response to NMDA similar to cyanide and the hydromorphone effect was blocked by cyanide scavengers. These data show that cyanide generation is increased in neuronal tissue by a mu-opiate receptor agonist and it is proposed that endogenous cyanide may modulate the NMDA receptor response.

Analgesics, Opioid↗
PubMed1975

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↗
PubMed2005

Application of cyanide hydrolase from Klebsiella sp. in a biosensor system for the detection of low-level cyanide.

A partially purified preparation of cyanide hydrolase (cyanidase) from a bacterium, Klebsiella sp., was applied as a biocatalyst in a biosensor system for low-level cyanide detection. In the biosensor system cyanide hydrolase converts cyanide into formate and ammonia. The formate produced in the cyanide degradation was detected with a formate biosensor, in which formate dehydrogenase (FDH; E.C. 1.2.1.2) was co-immobilized with salicylate hydroxylase (SHL; E.C. 1.14.13.1) on a Clark electrode. The principle of the formate sensor is that FDH converts formate into carbon dioxide using beta-nicotinamide adenine dinucleotide hydrate (NAD(+)). The corresponding NADH produced is then oxidized to NAD(+) by SHL using salicylate and oxygen. The oxygen consumption is monitored with the Clark electrode. The optimum buffer pH and temperature for the enzymatic hydrolysis of potassium cyanide were studied. The preliminary experiments including the pretreatment of cyanide with cyanide hydrolase and then detection by the formate sensor gave a detection limit at 7.3 micromol l(-1) cyanide. The linear range of the calibration curve was between 30 micromol l(-1) and 300 micromol l(-1) cyanide.

Ammonia↗
PubMed2003

The paradoxical cyanide-stimulated respiration of Zymomonas mobilis: cyanide sensitivity of alcohol dehydrogenase (ADH II).

The respiratory inhibitor cyanide stimulates growth of the ethanologenic bacterium Zymomonas mobilis, perhaps by diverting reducing equivalents from respiration to ethanol synthesis, thereby minimizing accumulation of toxic acetaldehyde. This study sought to identify cyanide-sensitive components of respiration. In aerobically grown, permeabilized Z. mobilis cells, addition of 200 microM cyanide caused gradual inhibition of ADH II, the iron-containing alcohol dehydrogenase isoenzyme, which, in aerobic cultures, might be oxidizing ethanol and supplying NADH to the respiratory chain. In membrane preparations, NADH oxidase was inhibited more rapidly, but to a lesser extent, than ADH II. The time-course of inhibition of whole-cell respiration resembled that of NADH oxidase, yet the inhibition was almost complete, and was accompanied by an increase of intracellular NADH concentration. Cyanide did not significantly affect the activity of ADH I, the zinc-containing alcohol dehydrogenase isoenzyme. When an aerobic batch culture was grown in the presence of 200 microM cyanide, cyanide-resistant ADH II activity was observed, its appearance correlating with the onset of respiration. It is concluded that the membrane-associated respiratory chain, but not ADH II, is responsible for the whole-cell cyanide sensitivity, while the cyanide-resistant ADH II is needed for respiration in the presence of cyanide, and represents an adaptive response of Z. mobilis to cyanide, analogous to the induction of alternative terminal oxidases in other bacteria.

Aerobiosis↗
PubMed1995

Relation of blood cyanide to plasma cyanocobalamin concentration after a fixed dose of hydroxocobalamin in cyanide poisoning.

Hydroxocobalamin combines with cyanide to form cyanocobalamin. We hypothesised that the amount of cyanocobalamin formed after a fixed dose of hydroxocobalamin given for cyanide poisoning would correlate with initial blood cyanide concentration. We determined blood cyanide concentration in 12 patients exposed to residential fires, and compared this with markers of the amount of cyanocobalamin formed after treatment with 5 g intravenous hydroxocobalamin. All relationships were highly correlated (r2 0.79-0.95), for the whole group, and there appeared to be an almost linear relationship for the 9 patients with initial cyanide concentration below 40 mumol/L. Above this concentration, no further cyanocobalamin was formed from a single 5 g dose of hydroxocobalamin. In one patient with initial blood cyanide concentration of 96 mumol/L, however, plasma cyanocobalamin concentration approximately doubled after a second 5 g dose of hydroxocobalamin. 5 g of hydroxocobalamin appears capable of binding all available cyanide ions for blood cyanide concentrations up to about 40 mumol/L. Beyond this, more hydroxocobalamin must be given for remaining cyanide ions to be bound. This information will allow clinicians to use rapidly measurable plasma cyanocobalamin concentrations to gauge severity of exposure and evaluate adequacy of treatment.

Adult↗
PubMed2002

Substrate-regulated cyanide hydratase (chy) gene expression in Fusarium solani: the potential of a transcription-based assay for monitoring the biotransformation of cyanide complexes.

The fungus Fusarium solani detoxifies cyanide through induction of the cyanide hydratase gene activity (chy) in the presence of either KCN or the metal-complexed cyanides, K2Ni(CN)4 or K4Fe(CN)6, at pH 7.0 and 4.0 respectively. Sequence analysis of the chy gene identified primers for reverse transcriptase-polymerase chain reaction (RT-PCR)-directed analysis of mRNA transcripts, which demonstrated that activity correlated to the substrate-specific induction of gene expression. chy transcription was initiated 30-60 min after exposure of F. solani cultures to cyanide complexes. Maximum expression was detected within 4.5 h, after which chy mRNA synthesis declined below the limits of detection within 26 h. A lag period of approximately 2 h, following initial transcription, was recorded before cyanide complexes were converted to formamide. mRNA transcripts of chy were not detected in the absence of cyanide or cyanide complexes. The presence of introns within the gene resulted in a difference in size of 100 bp for DNA compared with mRNA of the corresponding 5' region. This size difference facilitated PCR detection of gene and transcript respectively. Comparisons of the predicted amino acid sequence of the F. solani chy gene and those of Gloeocerospora sorghi, Fusarium lateritium and Leptosphaeria maculans demonstrate that cyanide hydratase genes are highly conserved and of a similar evolutionary origin. These data predict that the functional assay described here to monitor the induction of chy gene expression and, potentially, cyanide degradation would be applicable to a variety of polluted environments.

Amino Acid Sequence↗
PubMed2001

An assessment of the release of inorganic cyanide from the fragrance materials benzyl cyanide, geranyl nitrile and citronellyl nitrile applied dermally to the rat.

Organonitriles are widely used as components of fragrances that are incorporated into consumer products, many of which are for human topical use. Some organontriles are readily broken down metabolically to potentially toxic inorganic cyanide. Studies were therefore undertaken to assess whether this occurs with three representative fragrance nitriles, namely, benzyl cyanide, geranyl nitrile and citronellyl nitrile when applied dermally to the rat. The nitriles (benzyl cyanide, 150 mg/kg; geranyl and citronellyl nitriles, 400 mg/kg) were applied to the shaved backs of rats and maintained under occlusion for 24 h. Urine samples were collected for 0-24 h, 24-48 h and 48-72 h from the time of first application. These samples were analysed for thiocyanate, a biomarker for cyanide formation in vivo, as described previously (Potter, J., Smith, R.L., Api, A.M., 2000. Urinary thiocyanate levels as a biomarker for the generation of inorganic cyanide from benzyl cyanide in the rat. Food and Chemical Toxicology 39, 141-146). In the case of benzyl cyanide, there was a marked increase in urinary thiocyanate levels attributable to the release of cyanide in vivo. The amount of thiocyanate recovered was equivalent to 37% of the dose for males and 32% for females. For geranyl nitrile there was no significant increase in urinary thiocyanate excretion and there was only a marginal increase in the case of citronellyl nitrile that was equivalent to 0.40% of the applied dose for males and 0.29% for females.

Acetonitriles↗
PubMed1978

Properties of mitochondria isolated from cyanide-sensitive and cyanide-stimulated cultures of Acanthamoeba castellanii.

1. Mitochondria isolated from cultures of Acanthamoeba castellanii exhibit respiratory control and oxidize alpha-oxoglutarate, succinate and NADH with ADP:O ratios of about 2.4, 1.4 and 1.25 respectively. 2. Mitochondria from cultures of which the respiration was stimulated up to 50% by 1mm-cyanide (type-A mitochondria) and from cyanide-sensitive cultures (type-B mitochondria) had similar respiratory-control ratios and ADP:O ratios. 3. State-3 rates of respiration were generally more cyanide-sensitive than State-4 rates, and the respiration of type-A mitochondria was more cyanide-resistant than that of type-B mitochondria. 4. Salicylhydroxamic acid alone had little effect on respiratory activities of either type of mitochondria, but when added together with cyanide, irrespective of the order of addition, inhibition was almost complete. 5. Oxidation of externally added NADH by type-A mitochondria was mainly via an oxidase with a low affinity for oxygen (K(m)[unk]15mum), which was largely cyanide-sensitive and partially antimycin A-sensitive; this electron-transport pathway was inhibited by ADP. 6. Cyanide-insensitive but salicylhydroxamic acid-sensitive respiration was stimulated by AMP and ADP, and by ATP after incubation in the presence of MgCl(2). 7. Addition of rotenone to mitochondria oxidizing alpha-oxoglutarate lowered the ADP:O ratios by about one-third and rendered inhibition by cyanide more complete. 8. The results suggest that mitochondria of A. castellanii possess branched pathways of electron transport which terminate in three separate oxidases; the proportions of electron fluxes via these pathways vary at different stages of growth.

Adenine Nucleotides↗
PubMed1998

Cyanide hydrolysis in a cyanide-degrading bacterium, Pseudomonas stutzeri AK61, by cyanidase.

The cyanide-degrading bacterial strain AK61 was isolated from waste water at a metal-plating plant. The isolated strain was characterized by Gram-staining, quinone analysis, fatty acid profile and the API 20NE identification system, and identified as Pseudomonas stutzeri. Whole cells were able to degrade cyanide rapidly in a 1 mM solution containing no organic substances, and produced ammonia as a product. The induction of the cyanide-degrading activity of P. stutzeri AK61 did not depend on the presence of cyanide in the culture medium during growth. The cyanide-degrading enzyme was purified approximately 49-fold from a cell extract of P. stutzeri AK61. The enzyme had a K(m) of 1.7 mM for cyanide and a specific activity of 54.6 mumol ammonia produced min-1. The activity of the enzyme was optimal at 30 degrees C and pH 7.5. The results of SDS-PAGE, gel-filtration chromatography and NH2-terminal amino acid sequence analysis of the enzyme indicated that the functional enzyme was an aggregated protein consisting of a 38 kDa polypeptide. Like cyanidase (cyanide dihydratase), it was shown that the enzyme catalysed the hydrolysis of cyanide to ammonia and formate.

Amino Acid Sequence↗
PubMed1994

Interaction of cyanide with a dopamine metabolite: formation of a cyanohydrin adduct and its implications for cyanide-induced neurotoxicity.

Incubation of rat pheochromocytoma (PC12) cells with cyanide (1-10 mM) for 30 min produced a compound which eluted between dopamine (DA) and 3,4-dihydroxyphenylacetic acid in HPLC-EC analysis. Generation of the compound was rapid, concentration-dependent and blocked by pretreatment with clorgyline, a monoamine oxidase A inhibitor. In cell free incubation, the compound formed rapidly when cyanide was added to a mixture of monoamine oxidase and DA, but was not detected when cyanide was included with DA alone. The compound was radiolabelled when 14C-KCN was added to the incubation mixture. Based on these results, it is proposed that the deaminated metabolite of DA, 3,4-dihydroxyphenylacetaldehyde (DOPAL), reacts non enzymatically with cyanide to form the cyanohydrin adduct 2-hydroxy-3-(3,4-dihydroxyphenyl) propionitrile (HPN). HPN was confirmed by spectral analysis and co-elution with synthetic HPN. Incubation of mouse brain slices with cyanide (1 mM) generated 0.98 ng HPN/100 mg wet wt. over a 10 min period and HPN was detected in brains of mice after injection of cyanide (15.6 micrograms) into the lateral brain ventricle. Repeated doses of KCN (6 mg/kg, s.c., five times) produced 0.14 +/- 0.03 ng/100 mg of tissue in striatum. Incubation of PC12 cells for 60 min with 500 microM HPN killed 23% of the cells and increased DA release from the cells by 39.8% over untreated cells. Uptake of HPN into the cells was partially blocked by the catecholamine uptake inhibitor imipramine. These results indicate cyanide reacts with the DA metabolite DOPAL to generate a biologically active cyanohydrin adduct which may contribute to the neurotoxic response to cyanide.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1977

Application of cyanide-metabolizing enzymes to environmental control; enzyme thermistor assay of cyanide using immobilized rhodanese and injectase.

The application of the enzyme thermistor in the analysis of cyanide in standard solutions as well as in blast furnace waste water is described. The heat signal is generated in the conversion of cyanide, catalyzed by the immobilized enzymes rhodanese (E.C. 2.8.1.1) and injectase (E.C. 4.4.19). Using the combination of cyanide-metabolizing enzymes and the enzyme thermistor unit, assays down to 20 microM cyanide can be carried out. Linear relationships were obtained at 20-600 microM cyanide for injectase and 20-1000 microM for rhodanese. The stability at 27 degrees C of the heat response was initially decreased, but soon stabilized at about 80% of the initial value and remained so for at least 200 hr. The technique was easily adapted to continuous analysis, applicable to environmental control (e.g., a "cyanide guard") with a response time at present within 2-3 min after a sudden change in cyanide concentration has appeared.

Carbon-Sulfur Lyases↗
PubMed1996

Cell-free extract(s) of Pseudomonas putida catalyzes the conversion of cyanides, cyanates, thiocyanates, formamide, and cyanide-containing mine waters into ammonia.

Our isolate, Pseudomonas putida, is known to be capable of utilizing cyanides as the sole source of carbon (C) and nitrogen (N) both in the form of free cells and cells immobilized in calcium alginate. In the present study, the cell-free extract(s) were prepared from the cells of P. putida grown in the presence of sodium cyanide. The ability of enzyme(s) to convert cyanides, cyanates, thiocyanates, formamide and cyanide-containing mine waters into ammonia (NH3) was studied at pH 7.5 and pH 9.5. The kinetic analysis of cyanide and formamide conversion into NH3 at pH 7.5 and pH 9.5 by the cell-free extract(s) of P. putida was also studied. The Km and Vmax values for cyanide/formamide were found to be 4.3/8 mM and 142/227 mumol NH3 released mg protein-1 min-1 respectively at pH 7.5 and 5/16.67 mM and 181/434 mumol NH3 released mg protein-1 h-1 respectively at pH 9.5. The study thus concludes that the cell-free extract(s) of P. putida is able to metabolize not only cyanides, cyanates, thiocyanates, and formamide but also cyanide-containing mine waters to NH3.

Ammonia↗
PubMed1999

Synthesis, Structure, and Solution NMR Studies of Cyanide-Copper(II) and Cyanide-Bridged Iron(III)-Copper(II) Complexes.

A range of small molecules, such as cyanide, are known to bind and/or inhibit the active site of the heme-copper oxidase enzymes. As such, model studies are aimed at elucidating ligand binding modes and their subsequent impact on spectroscopic properties of derived complexes. We describe here the isolation and characterization of two compounds containing the Fe-CN-Cu moiety, [(py)(F(8)-TPP)Fe(III)-CN-Cu(II)(TMPA)](2+) (5) and [(F(8)-TPP)Fe(III)-(CN)(2)-{Cu(II)(TMPA)}(2)](3+) (6) [py = pyridine, TMPA = tris(2-pyridylmethyl)amine, and (F(8)-TPP) = tetrakis(2,6-difluorophenyl)porphyrinate(2-)]. [Cu(II)(TMPA)(CH(3)CN)](ClO(4))(2) and [(py)(F(8)-TPP)Fe(III)(CN)] (3) react to yield 5, while 6 is formed by combination of [Cu(II)(TMPA)(CN)]PF(6) (2-(PF(6))) and [(F(8)-TPP)Fe(III)(PF(6))] (4). Complex 2-(PF(6)) crystallizes in the orthorhombic space group Iba2 with a = 17.2269(5) Å, b = 17.3143(4) Å, and c = 14.4971(4) Å, Z = 8, complex (5-(Sb/P)F(6))(1.5)(ClO(4))(0.5) was obtained in the orthorhombic space group P222 with a = 17.9541(2) Å, b = 20.5359(1) Å, and c = 21.2023(2) Å, Z = 4, and 6-(PF(6))(3) crystallized in the monoclinic space group P2(1)/c with a = 15.318(4) Å, b = 33.921(2) Å, and c = 19.649(6) Å, beta = 109.69(2) degrees, and Z = 4. Compound 5 possesses a low-spin iron(III) center, bridged via cyanide to copper. The iron-cyanide vector deviates slightly from linearity (174.6(5) degrees ). The copper(II) ion is five-coordinated by the TMPA N-donor atoms and the cyanide carbon atom. The Cu(TMPA) moiety is bent with an angle of 163.8(5) degrees around the cyanide-copper vector. Compound 6 possesses a low-spin iron(III) atom axially coordinated by two cyanide ligands capped on either side by trigonally coordinated [Cu(TMPA)] moieties. The [Cu(1)(TMPA)] unit is twisted somewhat ( angleCu1-N&tbd1;C = 168 degrees ), whereas the [Cu(2)(TMPA)] unit is coordinated in a nearly linear fashion with respect to the cyanide-iron vector ( angleCu2-N&tbd1;C4 = 175 degrees ). (1)H and (2)H NMR spectroscopy on 5 and 6 confirmed the low-spin nature of these iron complexes (pyrrole resonance found at -11.1 and -8 ppm, respectively). The NMR data as well as observed solution magnetic moment (&mgr;(B) = 2.7 for 5; &mgr;(B) = 3.4 for 6) suggest ferromagnetic coupling between the paramagnetic metal ions. This gives rise to an enhancement of the electronic relaxation rate for Cu(II) in both 5 and 6 allowing for the observation of the sharp and downfield shifted TMPA ligand proton signals.

Journal Article↗
PubMed1983

Excretion of 14C-labeled cyanide in rats exposed to chronic intake of potassium cyanide.

The excretion of an acute dose of 14C-labeled cyanide in urine, feces, and expired air was studied in rats exposed to daily intake of unlabeled KCN in the diet for 6 weeks. Urinary excretion was the main route of elimination of cyanide carbon in these rats, accounting for 83% of the total excreted radioactivity in 12 hr and 89% of the total excreted radioactivity in 24 hr. The major excretion metabolite of cyanide in urine was thiocyanate, and this metabolite accounted for 71 and 79% of the total urinary activity in 12 hr and 24 hr, respectively. The mean total activity excreted in expired air after 12 hr was only 4%, and this value did not change after 24 hr. Of the total activity in expired air in 24 hr, 90% was present as carbon dioxide and 9% as cyanide. When these results were compared with those observed for control rats, it was clear that the mode of elimination of cyanide carbon in both urine and breath was not altered by the chronic intake of cyanide.

Animals↗