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PubMed1982

Effects of routes of administration on the cyanide concentration distribution in the various organs of cyanide-intoxicated rats.

Cyanide concentrations in various organs (the blood, liver, lung, spleen and brain) of the rats intoxicated by ingestion or inhalation were determined with a slightly modified microdiffusion method. In the inhalation experiment, a rat in an exposure chamber inhaled HCN produced by addition of NaCN solution to H2SO4. For each route two different doses were used. The time to death was shorter when doses were larger. Cyanide concentrations were higher in per os group than in inhalation group in all the organs tested. The concentration in the liver was most sensitive to the route of administration; it was the highest among the organs tested after per os administration, but low after inhalation. In the lung it was significantly higher than that of the blood when cyanide was inhaled. It was concluded that, when it is necessary to determine whether cyanide was ingested to inhaled, at least the lung and liver must be analyzed for cyanide contents in addition to the blood and stomach content.

Administration, Oral↗
PubMed1998

Molecular Heme-Cyanide-Copper Bridged Assemblies: Linkage Isomerism, Trends in nu(CN) Values, and Relation to the Heme-a(3)/Cu(B) Site in Cyanide-Inhibited Heme-Copper Oxidases.

Bovine heart cytochrome c oxidase and related heme copper oxidases are inhibited by cyanide, which binds at the binuclear heme-a(3)/Cu(B) site where dioxygen is reduced to water. To determine the mode of cyanide binding, heme-based binuclear complexes containing iron-cyanide-copper bridges in different oxidation states have been prepared by the reaction of [(py)(OEP)Fe(CN)] with Cu(II,I) precursors and structurally characterized by X-ray methods. Structures of two precursor complexes and two binuclear Cu(I)-CN-Cu(I) species are reported. The assembly [(py)(OEP)Fe-CN-Cu(Npy(3))](2+) has a nearly linear Fe(III)-CN-Cu(II) bridge containing low-spin Fe(III). The assemblies [(OEP)Fe-NC-Cu(MeNpy(2))](+) and [(OEP-CH(2)CN)Fe-NC-Cu(Npy(3))](+) exhibit the high-spin bridges Fe(III)-NC-Cu(I) and Fe(II)-NC-Cu(I), respectively. These are the first title bridges in these oxidation states. Bridge atom sequences are obtained from structural refinements of both linkage isomers; those for the reduced bridges are consistent with the soft-acid nature of Cu(I). Cyanide stretching frequencies respond to metal oxidation state and bridge geometry and, using data for solution and solid states, fall into the following ranges: Fe(III)-CN-Cu(II), 2120-2184 cm(-)(1) (11 examples); Fe(III)-NC-Cu(I), 2072-2100 cm(-)(1) (2 examples); Fe(II)-NC-Cu(I), 2099-2107 cm(-)(1) (1 example). These data are compared with nu(CN) values for the enzymes in different oxidation states. A nonlinear Fe(III)-CN-Cu(II) bridge (Cu-N-C = 150-160 degrees ) is consistent with the 2146-2152 cm(-)(1) range found for the fully oxidized enzymes. Bands that can be assigned with some certainty as Fe-CN vibrations in partially and fully reduced enzymes do not appear to correspond to Fe(III)-NC-Cu(I) and Fe(II)-NC-Cu(I) bridges but rather to Fe(II)-CN modes. The current work complements and extends our previous investigation (Scott and Holm, J. Am. Chem. Soc. 1994, 116, 11357) of linear and nonlinear Fe(III)-CN-Cu(II) bridges and is part of an investigation directed at providing a molecular basis of cyanide toxicity. (MeNpy(2) = bis(2-(2-pyridylethyl))methylamine; Npy(3) = tris(2-pyridylmethyl)amine; OEP = octaethylporphyrinate(2-), OEP-CH(2)CN = N-(cyanomethyl)octaethylporphyrinate(1-).)

Journal Article↗
PubMed2002

The first precise molecular structure of a monomeric transition metal cyanide, copper(I) cyanide.

Copper(I) cyanide is an important reagent in organic, organometallic, and supramolecular chemistry because of both the copper center and the versatile cyanide ligand. Solid-phase CuCN and many of its derivatives show oligomeric or polymeric structures, a trait shared by other metal cyanides. Often, it is difficult to specify the orientation of the cyano ligand in an X-ray structure. Here the first preparation and precise structure of a monomeric transition metal cyanide is reported. Gas-phase reaction between copper vapor and cyanogen (NCCN) clearly gives CuCN (not CuNC). The precise structure of CuCN so produced is determined by millimeter/submillimeter-wave spectroscopy. Because of the highly efficient synthesis and the presence of significant amounts of two copper isotopes, such strong signals were seen that natural-abundance materials allowed observation of transitions for the four isotopomers (63)Cu(12)C(14)N, (65)Cu(12)C(14)N, (63)Cu(13)C(14)N, and (63)Cu(12)C(15)N and the determination of r(o), r(s), and r(m)((2)) structures. All data unequivocally show a linear geometry and that the carbon of cyanide is bound to copper with a Cu-C distance of 1.82962(4) A in the r(m)((2)) structure, which is likely to be closest to the equilibrium geometry.

Journal Article↗
PubMedDate not supplied

Milk transfer of cyanide and thiocyanate: Cyanide exposure by lactation in goats.

The present work was aimed at evaluating the effects of maternal exposure to potassium cyanide (KCN) during lactation in goats. Twenty-seven lactating female goats were orally dosed with 0 (control), 1.0, 2.0, or 3.0 mg KCN/kg body weight/day from lactation days 0 to 90. After this period, all male kids and one mother from each group were killed for a pathological study. Cyanide treatment promoted the clinical signs of maternal toxicity in the highest KCN group but did not affect body weight. Both cyanide and thiocyanate presented increased levels in both dams and kids from the treated groups. Microscopic lesions, but without alterations on the biochemical panel, were found in the brain, thyroid, liver, and kidneys of both dams and kids from the treated groups. These findings suggest that lactating offspring can be indirectly intoxicated by maternal exposure to cyanide.

Animals↗
PubMed1988

Sodium nitroprusside, a convenient source of dietary cyanide for the study of chronic cyanide toxicity.

1. The suitability of sodium nitroprusside (SNP) as a source of dietary cyanide has been tested with growing chicks and with hens by measuring plasma or urinary thiocyanate; the major detoxication product of cyanide. 2. Growth and food intake were depressed and plasma thiocyanate concentration was increased in chicks in a progressive manner as the dietary concentration of SNP was increased from 0 to 0.5 g/kg. 3. In laying hens, urinary excretion of thiocyanate was increased fivefold by including SNP in the diet at 0.3 g/kg. 4. It is concluded that SNP is a suitable and convenient source of dietary cyanide for the investigation of chronic cyanide toxicity.

Animals↗
PubMed1993

Cyanide and methemoglobin kinetics in smoke inhalation victims treated with the cyanide antidote kit.

STUDY OBJECTIVE: To evaluate serial cyanide, methemoglobin, and carbon monoxide levels in smoke inhalation patients. SETTING: Regional poison center and regional toxicology treatment center. PARTICIPANTS: Seven critically ill smoke inhalation patients referred to the regional poison center. INTERVENTIONS: Peak level and half-life were determined by obtaining serial carboxyhemoglobin, cyanide, and methemoglobin levels. RESULTS: The mean observed half-life of cyanide was 3.0 +/- 0.6 hours. Methemoglobinemia was evaluated in four patients after sodium nitrite administration. The peak measured methemoglobin levels (mean, 10.5% +/- 2%; range, 7.9% to 13.4%) did not occur until a mean of 50 minutes (range, 35 to 70 minutes) following administration of sodium nitrite. The total oxygen-carrying capacity reduced by the combination of carboxyhemoglobin and methemoglobin was never more than 21% (range, 10% to 21%) in this series. CONCLUSION: The administration of sodium nitrite to smoke inhalation patients in the presence of concomitant carbon monoxide poisoning may be relatively safe.

Adult↗
PubMed1999

The respiratory responses to cyanide of a cyanide-resistant Klebsiella oxytoca bacterial strain.

The respiratory system of a cyanide-resistant Klebsiella oxytoca was analyzed by monitoring the changes in the cytochrome contents in response to various inhibitors in the presence of various concentrations of cyanide. The cells grown in the medium without cyanide (KCN) have two terminal oxidases, cytochrome d (Ki = 10(-5) M KCN) and o (Ki = 10(-3) M KCN). When cells were grown on medium with 1 mM KCN, the expression of both b-type cytochrome and cytochrome d in the plasma membranes of the cell decreased by more than 50%, while cytochrome o increased by 70%, as compared with the cells grown in the absence of KCN. Two terminal oxidases with Ki values of about 10(-3) M and 1.7 x 10(-2) M KCN were observed in the plasma membrane fractions of the cells growing on KCN enriched medium. 2-n-Heptyl-4-hydroxyquinoline-N-oxide markedly inhibited the oxidation of NADH by the plasma membranes from the cells grown in the medium without KCN, but not in those plasma membranes from KCN-grown cells. The NADH oxidases in plasma membranes of K. oxytoca grown with and without KCN were equally sensitive to UV irradiation. Adding freshly isolated quinone to the UV-damaged plasma membranes restored the NADH oxidase activity from both types of plasma membranes. From these results, we propose the presence of a non-heme type of terminal oxidase to account for the KCN resistance in K. oxytoca.

Cell Membrane↗
PubMed2005

Bacterial cyanide oxygenase is a suite of enzymes catalyzing the scavenging and adventitious utilization of cyanide as a nitrogenous growth substrate.

Cyanide oxygenase (CNO) from Pseudomonas fluorescens NCIMB 11764 catalyzes the pterin-dependent oxygenolytic cleavage of cyanide (CN) to formic acid and ammonia. CNO was resolved into four protein components (P1 to P4), each of which along with a source of pterin cofactor was obligately required for CNO activity. Component P1 was characterized as a multimeric 230-kDa flavoprotein exhibiting the properties of a peroxide-forming NADH oxidase (oxidoreductase) (Nox). P2 consisted of a 49.7-kDa homodimer that showed 100% amino acid identity at its N terminus to NADH peroxidase (Npx) from Enterococcus faecalis. Enzyme assays further confirmed the identities of both Nox and Npx enzymes (specific activity, 1 U/mg). P3 was characterized as a large oligomeric protein (approximately 300 kDa) that exhibited cyanide dihydratase (CynD) activity (specific activity, 100 U/mg). Two polypeptides of 38 kDa and 43 kDa were each detected in the isolated enzyme, the former believed to confer catalytic activity based on its similar size to other CynD enzymes. The amino acid sequence of an internal peptide of the 43-kDa protein was 100% identical to bacterial elongation factor Tu, suggesting a role as a possible chaperone in the assembly of CynD or a multienzyme CNO complex. The remaining P4 component consisted of a 28.9-kDa homodimer and was identified as carbonic anhydrase (specific activity, 2,000 U/mg). While the function of participating pterin and the roles of Nox, Npx, CynD, and CA in the CNO-catalyzed scavenging of CN remain to be determined, this is the first report describing the collective involvement of these four enzymes in the metabolic detoxification and utilization of CN as a bacterial nitrogenous growth substrate.

Cyanides↗
PubMed1975

Analytical isotachophoresis in capillary tubes. Analysis of hemoglobin, hemiglobin cyanide and isoelectric fractions of hemiglobin cyanide.

The zone stabilization in capillary isotachophoresis in the water phase has been improved by methylcellulose so that proteins can be analysed. Hemoglobin and hemiglobin cyanide samples were studied as model systems. Ampholine carrier ampholytes were used as spacers, enhancing the detection of the different components. The optimal amounts of Ampholine, however, were found to be much smaller than in most of the previously published reports. Linear relationships were found between the zone lengths and sample amounts, including spacers. The separations were reproducible and reached the isotachophoretic steady state. The hemiglobin cyanide was fractionated by isoelectric focusing. The four main fractions were then analyzed by capillary isotachophoresis and shown to be heterogeneous in mobility with a pH of 7.5 in the leading electrolyte. The component zones of the total hemiglobin cyanide sample were all identified in relation to the isotachophoretic components of the isoelectric fractions. The total analysis time was in average 30-40 min. The sample amounts were about 40 mug protein in each experiment with very small Ampholine volumes, 25-100 nl 40% (w/v).

Cellulose↗
PubMed2005

mer-[Fe(pcq)(CN)3]-: a novel cyanide-containing building block and its application to assembling cyanide-bridged trinuclear FeIII2MnII complexes [pcq- = 8-(pyridine-2-carboxamido)quinoline anion].

A new cyanide-containing building block K[Fe(pcq)(CN)(3)] [1; pcq(-) = 8-(pyridine-2-carboxamido)quinoline anion] containing a low-spin Fe(III) center with three cyanide groups in a meridional arrangement has been successfully designed and synthesized. Three cyanide-bridged trinuclear Fe(III)(2)Mn(II) complexes, [Fe(pcq)(CN)(3)](2)[Mn(CH(3)OH)(2)(H(2)O)(2)].2H(2)O (2), [Fe(pcq)(CN)(3)](2)[Mn(bipy)(2)].CH(3)OH.2H(2)O (3), and [Fe(pcq)(CN)(3)](2)[Mn(phen)(2)].CH(3)OH.2H(2)O (4), have been synthesized and structurally characterized. The magnetic susceptibilities of the three heterometallic complexes have been investigated.

Journal Article↗
PubMed2006

The vibrational spectra of the cyanide ligand revisited: terminal cyanides.

A comparison is made between the vibrational characteristics of the carbonyl and cyanide ligands. There are significant differences; the latter has a smaller dipole moment and a larger quadrupole moment associated with the bond stretch. This quadrupole moment may be linked to the observation that the totally symmetric nu(CN) mode does not lie at the highest frequency for some cyanide complexes. There are problems with the pi-bonding model commonly used to interpret the nu(CN) data. For instance, for the first transition row hexacyanoanions, the spectra are almost independent of t2g occupancy but are very sensitive to the formal charge. It is suggested that the observed nu(CN) frequency shifts on complex formation are in large measure determined by the effective charge on the cation to which the cyanide group is attached, and a new model, the Internal Vibrational Stark Effect, is suggested to account for this. The model is supported by DFT calculations. Raman spectra of some cubic cyano species are reported, along with polarization and intensity data.

Journal Article↗
PubMedDate not supplied

Exposures to carbon monoxide, hydrogen cyanide and their mixtures: interrelationship between gas exposure concentration, time to incapacitation, carboxyhemoglobin and blood cyanide in rats.

Carbon monoxide (CO) and hydrogen cyanide (HCN) are generated during aircraft interior fires in sufficient amounts to incapacitate cabin occupants. For typical post-crash and in-flight fires, minimum protection periods of 5 and 35 min, respectively, have been suggested for breathing devices to protect the occupants from smoke. Relationships of blood carboxyhemoglobin (COHb) and cyanide (CN-) levels to incapacitation have not been well defined for these gases. Therefore, time to incapacitation (ti) and blood COHb and CN- at incapacitation were examined in rats exposed to CO (5706 ppm for 5-min ti; 1902 ppm for 35-min ti), HCN (184 ppm for 5-min ti; 64 ppm for 35-min ti) and their mixtures (equipotent concentrations of each gas that produced 5- and 35-min ti). Blood CO and HCN uptakes were evaluated at the two concentrations of each gas. With either gas, variation in ti was higher for the 35-min ti than the 5-min ti The COHb level reached a plateau prior to incapacitation at both CO concentrations, and COHb levels at the 5- and 35-min ti were different from each other. Blood CN- increased as a function of both HCN concentration and exposure time, but CN- at the 5-min ti was half of the 35-min ti CN- level. The HCN uptake at the high concentration was about three times that at the low concentration. In the high concentration CO-HCN mixture, ti was shortened from 5 to 2.6 min; COHb dropped from 81 to 55% and blood CN- from 2.3 to 1.1 microgram ml(-1). At the low-concentration CO-HCN mixture, where ti was reduced from 35 to 11.1 min, COHb decreased from 71 to 61% and blood CN- from 4.2 to 1.1 microgram ml(-1). Any alteration in the uptake of either gas by the presence of the other was minimal. Our findings suggest that specific levels of blood COHb and CN- cannot be correlated directly with the incapacitation onset and that postmortem blood COHb and CN- levels should be evaluated carefully in fire victims.

Aircraft↗
PubMed1999

Disruption of the cyanide hydratase gene in Gloeocercospora sorghi increases its sensitivity to the phytoanticipin cyanide but does not affect its pathogenicity on the cyanogenic plant sorghum.

The release of hydrogen cyanide (HCN) from preformed cyanogenic compounds in plants such as sorghum is thought to provide a protective barrier against infection by microorganisms. Gloeocercospora sorghi, a fungal pathogen of sorghum, produces the enzyme cyanide hydratase (CHT) which converts HCN to the less toxic compound formamide. There is considerable prior evidence indicating that this mechanism for detoxifying HCN plays an important role in the pathogenicity of G. sorghi on sorghum. In the present study, the CHT gene was made nonfunctional in G. sorghi through transformation-mediated gene disruption. The transformant lacked CHT activity and no reacting polypeptides were detected with CHT-specific antibodies. This CHT mutant was highly sensitive to HCN, confirming that CHT is an HCN detoxifying mechanism, but it retained virulence on sorghum, causing lesions indistinguishable from those caused by the wild-type strain. This result indicates that G. sorghi does not require CHT for pathogenicity on cyanogenic lines of sorghum and suggests that cyanogenic compounds in plants may serve functions other than providing a mechanism of disease resistance.

Ascomycota↗
PubMed2006

Respiratory system of Gluconacetobacter diazotrophicus PAL5. Evidence for a cyanide-sensitive cytochrome bb and cyanide-resistant cytochrome ba quinol oxidases.

In highly aerobic environments, Gluconacetobacter diazotrophicus uses a respiratory protection mechanism to preserve nitrogenase activity from deleterious oxygen. Here, the respiratory system was examined in order to ascertain the nature of the respiratory components, mainly of the cyanide sensitive and resistant pathways. The membranes of G. diazotrophicus contain Q(10), Q(9) and PQQ in a 13:1:6.6 molar ratios. UV(360 nm) photoinactivation indicated that ubiquinone is the electron acceptor for the dehydrogenases of the outer and inner faces of the membrane. Strong inhibition by rotenone and capsaicin and resistance to flavone indicated that NADH-quinone oxidoreductase is a NDH-1 type enzyme. KCN-titration revealed the presence of at least two terminal oxidases that were highly sensitive and resistant to the inhibitor. Tetrachorohydroquinol was preferentially oxidized by the KCN-sensitive oxidase. Neither the quinoprotein alcohol dehydrogenase nor its associated cytochromes c were instrumental components of the cyanide resistant pathway. CO-difference spectrum and photodissociation of heme-CO compounds suggested the presence of cytochromes b-CO and a(1)-CO adducts. Air-oxidation of cytochrome b (432 nm) was arrested by concentrations of KCN lower than 25 microM while cytochrome a(1) (442 nm) was not affected. A KCN-sensitive (I(50)=5 microM) cytochrome bb and a KCN-resistant (I(50)=450 microM) cytochrome ba quinol oxidases were separated by ion exchange chromatography.

Bacterial Proteins↗
PubMed2002

Mild synthesis of disaccharidic 2,3-enopyranosyl cyanides and 2-C-2-deoxy pyranosyl cyanides with Hg(CN)(2)/HgBr(2)/TMSCN.

Lewis acid-catalyzed dimerization of mono- and disaccharidic per-O-acetylated glycals gave di- and tetrasaccharidic O-acetylated C-glycosides, respectively. 2,3-Enopyranosyl cyanides were obtained from per-O-acetylated glycals by a new, mild anomeric S(N)'-acetoxy displacement with Hg(CN)(2)/HgBr(2)/TMSCN. Per-O-acetylated 2-C-2-deoxy-pyranoses were converted into pyranosyl cyanides by the same reagent. An unprecedented acetic acid elimination from dimers with D-galacto- and L-fuco-configurations accompanied the S(N)-displacement under those conditions. A new set of (1)H NMR coupling constants for 2,3-enopyranosyl systems was used for configurational assignment of complicated tetrasaccharide mimics.

Acetylation↗
PubMed1980

Identification of the quinone species in cyanide-sensitive and cyanide-insensitive mitochondria of Moniliella tomentosa.

Moniliella tomentosa was investigated for the presence of different quinones that might be involved in the cyanide-sensitive and/or cyanide-insensitive electron-transport pathways. The naturally occurring quinone in Moniliella tomentosa was found to be ubiquinone-45. Other quinone species could not be detected. The concentration of ubiquinone-45 in mitochondria is not related to the presence or absence of the alternative oxidase activity.

Chromatography, Thin Layer↗
PubMed1982

The metabolism of cyanide and the gastrointestinal circulation of the resulting thiocyanate under conditions of chronic cyanide intake in the rat.

A study of the distribution of 14C-labelled cyanide was carried out in rats exposed to a regular intake of cyanide in the diet for 3 weeks. All tissues contained radioactivity 9 h after injection of 14CN- but very high amounts were found in the stomach, which accounted for 18% of the total injected radioactivity. Most of this was in the contents of the stomach, of which over 80% was in the form of thiocyanate. When a small amount of S14CN- was given by mouth to rats with elevated plasma thiocyanate levels, most of the activity was excreted in the urine and only small amounts were found in the faeces. This indicated the existence of a gastrointestinal circulation of thiocyanate, in which a substantial amount of this substance secreted into the stomach contents of the rat was reabsorbed by the intestine into the body fluid to be partly excreted in the urine and partly resecreted into the gastric contents. The likely implications of this are discussed.

Animals↗