Cyanide Levels Research Articles

Effect of garri processing effluents (waste water) on the cynide level of some root tubers commonly consumed in the south east Nigeria

Root tubers are the important staple food crops in the tropics, Nigeria inclusive. In the South East of Nigeria, the major staple root tuber crops include Dioscorea rotundata,(White yam) Dioscorea alata,(Water yam) Xanthosoma sagittifolium, (Red Cocoyam) Colocasia esculenta, (White Cocoyam) Ipomea batatas (Sweet potato) and Dioscorea dumetorum (Domestic yam). Due to inadequacies in supply, these tubers are always in high demand by consumers. To make up for the high demand, peasant farmers cultivate these tubers in any available space around homes. Around most homes in the villages are garri (cassava flour) processing factories, with the effluents (waste water) allowed to flow into adjoining farmlands without any form of treatment. It has been reported that cassava tubers and their effluents contain high concentrations of cyanide, thus the cyanide in the effluent may be adsorbed by the soil onto which it is disposed. Plants that are grown on soil of low potassium content and high nitrogen content have been reported to have high hydrocyanic acid concentration in their tubers. Numerous studies have described environmental exposure of humans to cyanide in African populations. Little is known about exposure to cyanide toxins from processed or unprocessed root tubers commonly consumed in Africa; and data on the food concentration of cyanide which is a potential poison and systemic toxicant is scanty. This study determined the concentrations of cyanide in some root tubers grown in a cassava processing plant effluent [waste water] contam inated farm land and commonly consumed in South East of Nigeria. Dioscorea rotundata had 10.13±1.9mgHCN/kg, while Dioscorea alata had 9.12±0.93mgHCN/kg. Xanthosoma sagittifolium and Colocasia esculenta were found to have values of 15.19±1.69mgHCN/kg and 11.81±1.19mgHCN/kg , respectively . Ipomea batatas [red cultivar] had cyanide level of 8.44±1.20 mgHCN/kg, while the white cultivar had 8.44±1.20mgHCN/kg . Dioscorea dumetorum [domestic] showed cyanide level of 35.44±1.69mgHCN/kg. These values are significantly [p<0.05] higher compared to values from the control site for the same cultivars , 9.65±1.36 mgHCN/kg, 8.45±1.60mgHCN/kg, 14.77±1.33mgHCN/kg and 10.89±1.55 mgHCN/kg , respectively while I. batatas and D. dumetorum had 7.26±1.34mgHCN/kg, 32.76±0.05mgHCN/kg , respectively . The difference in cyanide content between cultivars from the assumed contaminated site and control site could be as a result of environmental factors, like temperature, humidity, altitude and possibly the cassava effluent [waste water]. This preliminary study highlights the need to study the toxicological implications of chronic low –level exposure to cyanide from African root tubers as a result of poor waste disposal methods.

Hydrogen Cyanide Accumulation and Transformations in Non-polluted Salt Marsh Sediments

While cyanide is known to be produced by many organisms, including plants, bacteria, algae, fungi and some animals, it is generally thought that high levels of cyanide in aquatic systems require anthropogenic sources. Here, we report accumulation of relatively high levels of cyanide in non-polluted salt marsh sediments (up to 230 μmol kg−1). Concentrations of free cyanide up to 1.92 μmol L−1, which are toxic to aquatic life, were detected in the pore-waters. Concentration of total (free and complexed) cyanide in the pore-waters was up to 6.94 μmol L−1. Free cyanide, which is released to the marsh sediments, is attributed to processes associated with decomposition of cord grass, Spartina alterniflora, roots and possibly from other sources. This cyanide is rapidly complexed with iron and adsorbed on sedimentary organic matter. The ultimate cyanide sink is, however, associated with formation of thiocyanate by reaction with products of sulfide oxidation by Fe(III) minerals, especially polysulfides. The formation of thiocyanate by this pathway detoxifies two poisonous compounds, polysulfides and hydrogen cyanide, preventing release of free hydrogen cyanide from salt marsh sediments into overlying water or air.

Development of a Treatment Agent for Mass Casualty Smoke-Cyanide Exposure

Smoke inhalation is the major cause of death in fire victims. Combined cyanide and carbon monoxide poisoning is frequent in smoke inhalation victims, and mortality correlates more closely with cyanide levels than carbon monoxide exposure levels. There is currently no available treatment for mass casualty cyanide exposure, since treatment of individual victims requires administration of intravenous antidotes, and some antidote agents are contraindicated in smoke inhalation. We are developing a novel cyanide antidote, cobinamide, which could be administered intravenously or intramuscularly in mass casualty cyanide poisoning scenarios. Because cyanide antidotes cannot be tested for efficacy in humans, animal studies must be performed to demonstrate effectiveness of this agent in combined smoke-cyanide inhalation for FDA approval.METHODS: Six ventilator-supported New Zealand white rabbits were exposed to cold smoke breaths until toxic carbon monoxide levels were achieved (~30%), concurrent with intravenous cyanide infusion (0.167mg NaCN in 0.9% NaCl/min for 60 minutes). Animals were monitored with continuous gas exchange, hemodynamics, blood gases, cyanide levels, and diffuse optical spectroscopy, providing tissue oxy-and deoxyhemoglobin and cytochrome c oxidase measures in vivo. Intravenous cobinamide was administered in treatment arm animals and compared to control responses.RESULTS: Intravenous cobinamide reversed cyanide toxicity in these animals in the face of smoke induced carbon monoxide exposure, without evident adverse effects.CONCLUSIONS: Intravenous cobinamide shows promise as a potential antidote for cyanide poisoning in smoke inhalation victims, and an intramuscular formulation could potentially be administered in mass casualty exposure scenarios. Further validation and safety studies will be required for FDA approval of this promising agent.CLINICAL IMPLICATIONS: Treatment of fire smoke inhalation victims.DISCLOSURE: The following authors have nothing to disclose: Sasan Sani, Jangwoen Lee, Rene Patino, David Mukai, David Yoon, Sari Mahon, Gerry Boss, Steve Patterson, Matthew BrennerNo Product/Research Disclosure InformationBeckman Laser Institute, Irvine, CA. Language: en

Potential toxic levels of cyanide in cassava (Manihot esculenta Crantz) grown in Kenya

Cassava (Manihot esculenta Crantz) is a cyanogenic plant which is toxic when consumed without sufficient processing. Cassava is characterized by the presence of linamarin, a cyanogenic glycoside which can be hydrolyzed by endogenous linamarase enzyme to release hydrogen cyanide, in a process known as cyanogenesis. The study determined levels of cyanide in the sweet cassava variety collected from different districts in Kenya. Determination of cyanide contents of cassava was carried out spectrophotometrically using modified picrate paper method. Levels of cyanide in cassava varied significantly (p < 0.05) (n = 324) across the geographical location. Cyanide content of cassava from Kakamega was highest [80.79 ± 4.55 mg hydrogen cyanide (HCN) equivalents/kg of fresh cassava weight] followed by those from Kitui (70.46 ± 2.21 mg HCN equivalents/kg of fresh cassava weight), while cassava from Kisii had the lowest cyanide concentration (43.27 ± 3.75 mg HCN equivalents/kg of fresh cassava weight). The cyanide concentrations of cassava from the rest of the regions such as Nairobi and Thika fall in the middle, 66.00 ± 2.12 and 54.84 ± 6.5 mg HCN equivalents/kg of fresh cassava weight respectively. Nonetheless, the cyanide contents of cassava from the sampled regions were greater than the accepted level (10 mg/kg) by the World Health Organization (WHO). Key words: Cyanogenic glycoside, linamarase, cyanide, linamarin, cassava.

Pilot test operation of biological nitrogen removal of gold mill effluents

Effluents from gold mills are a potential environmental hazard, unless toxic substances such as nitrogen compounds (sodium cyanide, thiocyanate and ammonia) and heavy metals are removed. In northern Sweden, there are gold mines that are either already in operation, or to be opened, among them is the proposed Lappland Goldminers AB gold mill facility. The environmental permit for this new activity requires stringent removal levels of nitrogen. It was decided to operate a pilot plant to study the biological nitrogen removal performance. It has been based on a continuous activated sludge plant suited for biological nutrient removal. The plant has been operated at a neighbouring gold mill plant with an identical gold extraction process. The pilot study focused primarily on nitrification; however, also the denitrification performance and cyanide removal were monitored. The test results have been encouraging, showing up to a 100% nitrification capacity. The specific nitrification rate has been in the range (0.5) of 1.1–2.6g Nox/kg VSS/h, at temperatures ranging from 7.6 to 20°C. Different unintended process disturbances have been allowed for conclusions on the process stability and recovery potential. Low levels of total cyanide were recorded in the inlet, but virtually no traces were found in the treated water.

Study on Pressure-Cyanide Dissolution of Metal Platinum Powder

A research study has been undertaken to develop the fundamentals of a method for the direct dissolution of Metal Platinum. At room temperature and pressures, the reaction between sodium cyanide and platinum group metals (PGMs) does not occur because of poor kinetics. However, at elevated temperatures between 20°C and 180°C, PGMs can be dissolved by sodium cyanide like the reaction of gold. In this work, the dissolution of Platinum was measured in pressure clear cyanide solution. The data at different cyanide concentrations, different temperature and different oxygen pressure are obtained. With increasing cyanide concentration and oxygen pressure, the dissolution first increased to a maximum value and then decreased. With increasing temperature the dissolution is increased. The dissolution was found to have a relation of the cyanide and oxygen level. The dissolution was independent of rotation speed for oxygen-saturated solutions and cyanide concentrations above 5 mol.m-3 and was well below chemical reaction-limited for cyanide and oxygen.

Study on Pressure-Cyanide Dissolution of Metal Palladium Powder

A research study has been undertaken to develop the fundamentals of a method for the direct dissolution of Metal Palladium. At room temperature and pressures, the reaction between sodium cyanide and platinum group metals (PGMs) does not occur because of poor kinetics. However, at elevated temperatures between 100°C and 180°C, PGMs can be dissolved by sodium cyanide like the reaction of gold. In this work, the dissolution of Palladium was measured in pressure clear cyanide solution. The data at different cyanide concentrations, different temperature and different oxygen pressure are obtained. With increasing cyanide concentration and oxygen pressure, the dissolution first increased to a maximum value and then decreased. With increasing temperature the dissolution is increased. The dissolution was found to have a relation of the cyanide and oxygen level. The dissolution were independent of rotation speed for oxygen-saturated solutions and cyanide concentrations above 5 mol.m-3 and were well below chemical reaction-limited for cyanide and oxygen.

Toxic Leukoencephalopathy Due to Yam Bean Seeds Poisoning

Toxic leukoencephalopathy is attributed to exposure to a wide variety of agents, including systemic chemotherapy, cranial irradiation, illicit drug abuse, and toxins from the environment. Diagnosis of this disease requires documented exposure to a toxin, neurobehavioral deficits, and typical neuroimaging abnormalities. Intoxication by compounds extracted from yam bean seeds may mimic cyanide poisoning but fail to respond to antidotal therapy. We report a 54-year-old Chinese woman who developed disturbed consciousness after eating 40 pieces of yam bean seeds. Head computed tomography obtained 24 hours after the episode was normal. However, magnetic resonance imaging obtained 20 days after the episode revealed symmetrical faint high signal over the bilateral periventricular white matter on T1-weighted image, which turned into diffuse and symmetrical bright high signal on FLAIR. The diagnosis of this patient was toxic leukoencephalopathy by yam bean seeds intoxication. The changes in brain images after yam bean seeds intoxication have not ever been reported. Physicians in Asia and the Pacific islands should have a high index of suspicion when they care for patients with acute confusion and a high anion gap metabolic acidosis but normal serum cyanide level.

The Effect of Different Fermentation Techniques on the Nutritional Quality of the Cassava Product (fufu)

The nutritional qualities of fufu produced from traditional, brine and backslopping fermentation techniques were evaluated. The cassava roots were steeped in water (1:4 kg/L) for 96 h for the production of traditional-fermented sample while fermented cassava liquor (10%w/v) was used to initiate fermentation in the backslopping technique. Two-staged method that involved fermentation and grating was employed for the production of brine-fermented sample. The resultant “wet fufu” samples were dried at 65C in a cabinet dryer and mechanically milled into flour. The hydrogen cyanide level, proximate composition, functional properties, mineral contents and the sensory evaluation of the flour samples were assessed. Lactic acid bacteria populations comprised more than 95% of the total viable bacteria and remained prominent through the fermentations, while the number of coliforms and moulds declined as the fermentation progressed. Lactobacillus plantarum, L. buchnerii, L. casei were implicated in the brine fermentation. The hydrogen cyanide observed after fermentation and processing were 15.67 ± 0.63 mg/kg, 13.29 ± 0.68 mg/kg and 12.07 ± 0.32 mg/kg for the traditional, brine and backslopping-fermented samples, respectively. Lowest moisture content (10.61 ± 0.15%) was recorded in backslopping-fermented sample and highest (12.69 ± 0.34%) in traditional-fermented sample. The ash and carbohydrate contents range from 0.76 ± 0.23% to 0.92 ± 0.27% and 82.57 ± 0.56% to 84.03 ± 0.58%, respectively. Higher protein contents were observed in brine (2.25 ± 0.19%) and backslopping (2.32 ± 0.13%) fermentations while the lowest crude fiber content (0.84 ± 0.43%) was obtained in the brine-fermented sample. The results of the functional properties show similar trend. Brine and backslopping fermentation techniques offer lighter “fufu” flours and dough as indicated by the lower swelling index (3.16 ± 0.09 g/g and 2.66 ± 0.18 g/g, respectively) and bulk density (0.65 ± 0.03 g/mL and 0.57 ± 0.03 g/mL, respectively). The traditional-fermented sample had the highest water absorption capacity (4.89 ± 0.06%). Brine fermentation significantly (P < 0.05) increased the Ca (0.235 ± 0.004 mg/kg), Na (0.555 ± 0.055 mg/kg) and K (0.504 ± 0.009 mg/kg) contents of fufu flour than the traditional fermentation which were 0.162 ± 0.003 mg/kg, 0.0097 ± 0.011 mg/kg and 0.151 ± 0.003 mg/kg respective. Sensory scores showed that production of fufu using brine fermentation is more preferred than traditional fermentation. PRACTICAL APPLICATIONS In recent times, attention has been drawn to the enrichment of protein in cassava products by various methods. However, brine and backslopping fermentation techniques of cassava roots are valuable biotechnological approach in achieving this. Because cassava has been recognized as a suitable crop for micronutrient intervention in Africa, its planting and processing into various products like “fufu” flour should be encouraged. Fabrication of cheap local dryer, which can hygienically convert the “fufu wet cake” into flours is strongly recommended and should be made available in the rural areas where larger population of the consumers of this cassava product are located.

Effect of Nitrogen Fertilizer on the Levels of Some Nutrients, Anti-nutrients and Toxic Substances in Hibiscus sabdariffa

The presence of antinutrients and toxic substances in vegetables limits the derivable benefits from vegetables. The levels of these substances in vegetables are influenced by the nature of soil in which the vegetables are grown. The effect of applied nitrogen fertilizer on the levels of some antinutrients and toxic substances is investigated with a view to determine the appropriateness or otherwise of the application of nitrogen fertilizer in growing vegetables. Pot experiments were conducted to determine the effect of soil nitrogen levels on soluble and total oxalates, cyanide, nitrate and some micronutrients namely, vitamin C, β-carotene (precursor of vitamin A) and mineral elements (Fe, Mg, Zn, Cu, Ca, Na and K) in Hibiscus sabdariffa. The leaves of the vegetable were harvested and analysed at market maturity (vegetative phase) and fruiting (reproductive phase) of the plant development. Results obtained showed that the applied nitrogen fertilizer significantly elevated nitrate and β-carotene contents, while it decreases the levels of vitamin C, soluble and total oxalates in the vegetable. The levels of cyanide and mineral elements were not significantly affected by the applied nitrogen fertilizer.

Bioavailability of cyanide and metal–cyanide mixtures to aquatic life

Cyanide can be toxic to aquatic organisms, and the U.S. Environmental Protection Agency has developed ambient water-quality criteria to protect aquatic life. Recent work suggests that considering free, rather than total, cyanide provides a more accurate measure of the biological effects of cyanides and provides a basis for water-quality criteria. Aquatic organisms are sensitive to free cyanide, although certain metals can form stable complexes and reduce the amount of free cyanide. As a result, total cyanide is less toxic when complexing metals are present. Cyanide is often present in complex effluents, which requires understanding how other components within these complex effluents can affect cyanide speciation and bioavailability. The authors have developed a model to predict the aqueous speciation of cyanide and have shown that this model can predict the toxicity of metal-cyanide complexes in terms of free cyanide in solutions with varying water chemistry. Toxicity endpoints based on total cyanide ranged over several orders of magnitude for various metal-cyanide mixtures. However, predicted free cyanide concentrations among these same tests described the observed toxicity data to within a factor of 2. Aquatic toxicity can be well-described using free cyanide, and under certain conditions the toxicity was jointly described by free cyanide and elevated levels of bioavailable metals.

Assessing levels of hydrogen cyanide in fire experiments using a generalized correlation

A generalized relationship between the normalized yields of carbon monoxide and hydrogen cyanide for nitrogen-containing materials has recently been derived. This correlation is used in the current study to analyze experimentally derived hydrogen cyanide data from three sets of fire tests. For a reduced-scale compartment fire test, the yields of hydrogen cyanide with varied equivalence ratios and the transient hydrogen cyanide concentrations are estimated; for a series of room-corridor sofa fire tests, the extremely high hydrogen cyanide level observed is demonstrated to be a realistic result and a hydrogen cyanide yield value of 0.047 g/g is suggested for this sofa in post-flashover fires for fire safety assessments; and finally, for a series of smoke chamber tests with polyurethane, possible causes for the failure to detect hydrogen cyanide are suggested. Language: en

Characterization of Cassava Flour with Protein Concentrate Prepared from the Leaves of Cassava (Manihot esculenta Crantz)

The use of biomass has become a concern world-wide, especially in Brazil, a country rich in diversity and quantity of food. However, thousands of Brazilians are still hungry, while much of the biomass is wasted. This is especially true in subsistence cultures. Cassava (Manihot esculenta Crantz) is an excellent example. During the harvest all its shoots are left in the field. The leaves of this plant contain important nutrients that can be used in the diet, such as the protein concentrate (PC) portion. Given the nutritional importance of cassava flour for the Brazilian population, the aims of this study were to produce and characterize the cassava flour with PC. Using the cassava leaves PC increases the nutritional value and takes advantage of what was once just an agricultural waste. Adding PC promoted a significant increase in the amounts of protein, ash, lipids, fiber and acidity, and decreased the starch content. The PC did not have high enough cyanide levels to be considered dangerous and it was free from microbiological contamination, in accordance with Brazilian laws. The application of PC was effective in increasing the protein quality of cassava flour, a product essentially consumed for the energy and power it provides to Brazilians, especially the north and northeast, where the incidence of malnutrition is higher. Keywords: Agricultural residues, protein, cassava, flour, family, cultivation, fructose, glucose, carbohydrates, cyanogem

Hydroxocobalamin and Epinephrine Both Improve Survival in a Swine Model of Cyanide-Induced Cardiac Arrest

To determine whether hydroxocobalamin will improve survival compared with epinephrine and saline solution controls in a model of cyanide-induced cardiac arrest. Forty-five swine (38 to 42 kg) were tracheally intubated, anesthetized, and central venous and arterial continuous cardiovascular monitoring catheters were inserted. Potassium cyanide was infused until cardiac arrest developed, defined as mean arterial pressure less than 30 mm Hg. Animals were treated with standardized mechanical chest compressions and were randomly assigned to receive one of 3 intravenous bolus therapies: hydroxocobalamin, epinephrine, or saline solution (control). All animals were monitored for 60 minutes after cardiac arrest. Additional epinephrine infusions were used in all arms of the study after return of spontaneous circulation for systolic blood pressure less than 90 mm Hg. A sample size of 15 animals per group was determined according to a power of 80%, a survival difference of 0.5, and an α of 0.05. Repeated-measure ANOVA was used to determine statistically significant changes between groups over time. Baseline weight, time to arrest, and cyanide dose at cardiac arrest were similar in the 3 groups. Coronary perfusion pressures with chest compressions were greater than 15 mm Hg in both treatment groups indicating sufficient compression depth. Zero of 15 (95% confidence interval [CI] 0% to 25%) animals in the control group, 11 of 15 (73%; 95% CI 48% to 90%) in the hydroxocobalamin group, and 11 of 15 (73%; 95% CI 48% to 90%) in the epinephrine group survived to the conclusion of the study (P<.001). The proportion of animals with return of spontaneous circulation at 5 minutes was 4 of 15 (27%; 95% CI 10% to 52%), and that of return of spontaneous circulation at 10 minutes was 11 of 15 (73%; 95% CI 48% to 90%) in the 2 treatment groups. Additional epinephrine infusion after return of spontaneous circulation was administered for hypotension in 2 of 11 (18%; 95% CI 4% to 48%) hydroxocobalamin animals and in 11 of 11 (100%; 95% CI 70% to 100%) of the epinephrine animals (P<.001). At 60 minutes, serum lactate was significantly lower in the hydroxocobalamin group compared with the epinephrine group (4.9 [SD 2.2] versus 12.3 [SD 2.2] mmol/L), and the pH was significantly higher (7.34 [SD 0.03] versus 7.15 [SD 0.07]). Serial blood cyanide levels in the hydroxocobalamin group were also lower than that of the epinephrine group from cardiac arrest through the conclusion of the study. Intravenous hydroxocobalamin and epinephrine both independently improved survival compared with saline solution control in our swine model of cyanide-induced cardiac arrest. Hydroxocobalamin improved mean arterial pressure and pH, decreased blood lactate and cyanide levels, and decreased the use of rescue epinephrine therapy compared with that in the epinephrine group.

Cytochrome c biosensor for determination of trace levels of cyanide and arsenic compounds

An electrochemical method based on a cytochrome c biosensor was developed, for the detection of selected arsenic and cyanide compounds. Boron doped diamond (BDD) electrode was used as a transducer, onto which cytochrome c was immobilised and used for direct determination of Prussian blue, potassium cyanide and arsenic trioxide. The sensitivity as calculated from cyclic voltammetry (CV) and square wave voltammetry (SWV), for each analyte in phosphate buffer (pH=7) was found to be in the range of (1.1–4.5)×10−8AμM−1 and the detection limits ranged from 4.3 to 9.1μM. The biosensor is therefore able to measure significantly lower than current Environmental Protection Agency (EPA) and World Health Organisation (WHO) guidelines, for these types of analytes. The protein binding was monitored as a decrease in biosensor peak currents by SWV and as an increase in biosensor charge transfer resistance by electrochemical impedance spectroscopy (EIS). EIS provided evidence that the electrocatalytic advantage of BDD electrode was not lost upon immobilisation of cytochrome c. The interfacial kinetics of the biosensor was modelled as equivalent electrical circuit based on electrochemical impedance spectroscopy data. UV–vis spectroscopy was used to confirm the binding of the protein in solution by monitoring the intensity of the soret bands and the Q bands. FTIR was used to characterise the protein in the immobilised state and to confirm that the protein was not denatured upon binding to the pre-treated bare BDD electrode. SNFTIR of cyt c immobilised at platinum electrode, was used to study the effect of oxidation state on the surface bond vibrations. The spherical morphology of the immobilised protein, which is typical of native cytochrome c, was observed using scanning electron microscopy (SEM) and confirmed the immobilisation of the cytochrome c without denaturisation.

Hydroxocobalamin Versus Sodium Thiosulfate for the Treatment of Acute Cyanide Toxicity in a Swine (Sus scrofa) Model

We compare the efficacy of hydroxocobalamin to sodium thiosulfate to reverse the depressive effects on mean arterial pressure in a swine model of acute cyanide toxicity and gain a better understanding of the mechanism of action of the hydroxocobalamin in reversal of the toxicity. Swine were intubated, anesthetized, and instrumented with central arterial and venous lines and a pulmonary artery catheter. Animals (n=36) were randomly assigned to one of 3 groups: hydroxocobalamin alone (150 mg/kg), sodium thiosulfate alone (413 mg/kg), or hydroxocobalamin (150 mg/kg)+sodium thiosulfate (413 mg/kg) and monitored for 60 minutes after the start of antidotal infusion. Cyanide was infused until severe hypotension developed, defined as blood pressure 50% of baseline mean arterial pressure. Repeated-measures ANOVA was used to determine statistically significant changes between groups over time. Time to hypotension (25, 28, and 33 minutes), cyanide dose at hypotension (4.7, 5.0, and 5.6 mg/kg), and mean cyanide blood levels (3.2, 3.7, and 3.8 μg/mL) and lactate levels (7, 8.2, 8.3 and mmol/L) were similar. All 12 animals in the sodium thiosulfate group died compared with 2 of 12 in the hydroxocobalamin/sodium thiosulfate group and 1 of 12 in hydroxocobalamin group. No statistically significant differences were detected between the hydroxocobalamin and hydroxocobalamin/sodium thiosulfate groups for carbon monoxide, mean arterial pressure, cyanide levels, or mortality at 60 minutes. Lactate level (2.6 versus 2.1 mmol/L), pH (7.44 versus 7.42), and bicarbonate level (25 versus 26 mEq/L) at 60 minutes were also similar between groups. Sodium thiosulfate failed to reverse cyanide-induced shock in our swine model of severe cyanide toxicity. Further, sodium thiosulfate was not found to be effective when added to hydroxocobalamin in the treatment of cyanide-induced shock. Hydroxocobalamin alone was again found to be effective for severe cyanide toxicity.

Cytotoxicity of cyanide in primary culture of rat hepatocytes and its interaction with alpha-ketoglutarate

Cyanide is primarily a neurotoxin but its hepatotoxic and nephrotoxic potentials are also known. The present study reports the effect of alpha-ketoglutarate A-KG (2.5–20 mM; 0 min), a potential cyanide antidote on potassium cyanide (KCN; 1.25–20 mM) induced cytotoxicity in primary culture of rat hepatocytes. Cytotoxicity measured at various time points (0.5–24 h), was characterized by increased leakage of intracellular lactate dehydrogenase, alanine aminotransferase and aspartate aminotransferase, accompanied by diminished mitochondrial function (MTT assay), mitochondrial membrane potential (Rhodamine 123 assay), and ATP levels. However, lipid peroxidation (malondialdehyde assay) and DNA damage were not observed. In a separate study, levels of cyanide, AKG and thiocyanate were measured in the culture medium of hepatocytes, treated with KCN (5 mM) and/or A-KG (5 or 10 mM; 0 min), and in the serum of rats given oral treatment of KCN (10 mg/kg) and/or A-KG(0.5, 1 or 2 g/kg; 0 min). Cyanide and A-KG interaction was best exhibited when both were added in equimolar dose in vitro. In rats, cyanide levels were significantly reduced by 1 and 2 g/kg A-KG. It can be concluded from the results that, (i) a very high dose of cyanide is required to produce cytotoxicity and other cellular perturbations in rat hepatocytes, (ii) cytotoxicity is independent of lipid peroxidation and DNA damage, (iii) A-KG provides significant protection against cyanide, particularly at equimolar dose in vitro, and (iv) a very high dose of A-KG is required for cyanide detoxification in vivo, suggesting that the dose of A-KG could be reduced by improving its bioavailability.

Detoxification and Consumption of Cassava Based Foods in South West Ethiopia

Cassava (Manihot esculenta) was introduced in Ethiopia around 1960‘s. But the consumption was not practiced until 1984. Currently the plant is being distributed throughout the country as a tool to tackle food insecurity. However, the distribution is not supported by proved food preparation techniques for optimal processing to increase nutrient density and eliminate the toxin. Hence, development of suitable detoxification methods and optimal food processing without affecting consumers acceptance is essential. The aim of this paper is to evaluate the existing processing technologies in order to identify effective methods for reducing the cyanide content and improve nutritional quality of cassava based foods. Primary and secondary data were collected from four cassava producing and consuming districts of south west Ethiopia using Focus Group Discussion (FGD), key informants interview and review of written documents. Processing methods such as washing, boiling, drying and fermenting with flour of cereals were evaluated to increase nutritional content and reduce cyanide level. Laboratory and kitchen trial of cassava mix with cereals at two levels were conducted to evaluate the toxin content and nutritional value of products. In this study solar drying and fermentation were found to be the best methods in totally removing the cyanide content of cassava. The results show that both cassava mix are suitable (at 95%CI) for Anebabero, Injera, Dabbo (Bread) and porridge preparation. Cereal blends improve nutritional quality of cassava based foods.

Swedish forensic data 1992–2009 suggest hydrogen cyanide as an important cause of death in fire victims

Between 60 and 80% of all deaths related to fire are attributed to toxic fumes. Carbon monoxide (CO) is commonly thought to be the major cause. However, hydrogen cyanide (HCN) is also formed. Still, the exact contribution of HCN to fire-related fatalities is unknown. The aim of the study was to investigate the impact of HCN in relation to CO as a cause of death in fire victims. Data on carboxyhemoglobin (COHb) and blood cyanide from deceased fire victims in the period 1992–2009 were collected from two Swedish nationwide forensic databases (ToxBase and RättsBase). The databases contain data on COHb and/or cyanide from 2303 fire victims, whereof 816 on both COHb and cyanide. Nonparametric statistical tests were used. Seventeen percent of the victims had lethal or life-threatening blood cyanide levels (>1 µg/g) and 32% had lethal COHb levels (>50% COHb). Over 31% had cyanide levels above 0.5 µg/g, an indication of significant HCN exposure. The percentages may be underestimates, as cyanide is quickly eliminated in blood also after death. Our results support the notion that HCN contributes more to the cause of death among fire victims than previously thought.

Reactive Photonic Film for Label‐Free and Selective Sensing of Cyanide

Three-dimensional ordered inverse-opal films bearing a reactive trifluoroacetyl group are successfully constructed. Through the specific reaction between cyanide and trifluoroacetyl, the photonic films can selectively detect sub-micromolar levels of cyanide by distinct structural color change. Labeled molecules are not necessary for the sensing mechanism.