Cyanide Levels Research Articles

Sodium nitroprusside-associated cyanide toxicity in adult patients – fact or fiction? A critical review of the evidence and clinical relevance

Sodium nitroprusside-associated cyanide toxicity in adult patients – fact or fiction? A critical review of the evidence and clinical relevance Alissa Lockwood1, John Patka2, Marina Rabinovich2, Katleen Wyatt2, Prasad Abraham21Department of Pharmacy, Parkland Health System, Dallas, TX, USA; 2Department of Pharmacy and Drug Information, Grady Health System, Atlanta, GA, USAAbstract: Since its US Food and Drug Administration (FDA) approval in 1974, sodium nitroprusside (SNP) has been fraught with controversy in regards to its safety. Over the years, a growing concern related to SNPs propensity to cause cyanide (CN) toxicity culminated into a series of case reports that led the FDA to develop a black-box warning with dose limitations of <2 µg/kg/min. These recommendations stemmed also from the reality of the difficulty of obtaining CN levels in a timely manner, as well as the presumed poor correlation of metabolic markers (lactate levels and pH) as it related to the severity of CN toxicity. All these issues have driven practitioners to the use of alternative agents. In this paper, we critically review the cases and the data that led to the development of these restrictive dosing recommendations and reveal several limitations of the data and assumptions that led to these recommendations. We conclude that SNP is still a reasonable agent to use in the management of patients with hypertension today and can safely be used beyond doses of 2 µg/kg/min. Furthermore, in lieu of CN levels, monitoring of lactic acid levels is also a reasonable measure to ensure safety.Keywords: dose limits, monitoring, controversy, thiosulfate stores, cyanide levels

Effects of processing on the mineral content, proximate composition and phytochemical factors of the seeds of bauhinia monandra (kurz)

The mineral content, nutritive value and anti-nutritional factors in boiled seeds of Bauhinia monandra collected from the main campus of Ahmadu Bello University, Zaria, Nigeria were evaluated. Mineral content analysis revealed concentrations of Potassium 103.33mg/g, Iron 75.92mg/g, Calcium 56.55mg/g, Sodium 53.33mg/g, Phosphorus 47.60mg/g, Magnesium 43.33mg/g, and Zinc 01.11mg/g. Proximate composition of the seeds showed high crude protein in the boiled (25.75-31.69mg/g) and low crude fiber (7.11-10.75mg/g) in the raw samples. Phytochemical screening of the seeds showed that the concentration of Hydrogen cyanide, fluorine and sulphur levels reduced significantly (P

Sulfanegen sodium treatment in a rabbit model of sub-lethal cyanide toxicity

The aim of this study is to investigate the ability of intramuscular and intravenous sulfanegen sodium treatment to reverse cyanide effects in a rabbit model as a potential treatment for mass casualty resulting from cyanide exposure. Cyanide poisoning is a serious chemical threat from accidental or intentional exposures. Current cyanide exposure treatments, including direct binding agents, methemoglobin donors, and sulfur donors, have several limitations. Non-rhodanese mediated sulfur transferase pathways, including 3-mercaptopyruvate sulfurtransferase (3-MPST) catalyze the transfer of sulfur from 3-MP to cyanide, forming pyruvate and less toxic thiocyanate. We developed a water-soluble 3-MP prodrug, 3-mercaptopyruvatedithiane (sulfanegen sodium), with the potential to provide a continuous supply of substrate for CN detoxification. In addition to developing a mass casualty cyanide reversal agent, methods are needed to rapidly and reliably diagnose and monitor cyanide poisoning and reversal. We use non-invasive technology, diffuse optical spectroscopy (DOS) and continuous wave near infrared spectroscopy (CWNIRS) to monitor physiologic changes associated with cyanide exposure and reversal. A total of 35 animals were studied. Sulfanegen sodium was shown to reverse the effects of cyanide exposure on oxyhemoglobin and deoxyhemoglobin rapidly, significantly faster than control animals when administered by intravenous or intramuscular routes. RBC cyanide levels also returned to normal faster following both intramuscular and intravenous sulfanegen sodium treatment than controls. These studies demonstrate the clinical potential for the novel approach of supplying substrate for non-rhodanese mediated sulfur transferase pathways for cyanide detoxification. DOS and CWNIRS demonstrated their usefulness in optimizing the dose of sulfanegen sodium treatment.

Simple picrate method for the determination of cyanide in cassava flour

A simple picrate method was used to quantify the cyanide contents of food samples. The cyanide in the food samples reacted with hot 20% HCl solution to produce hydrogen cyanide vapour which reacted with alkaline picrate test strips to form red colour on the test strips. The red coloured complex on the strips was extracted with 50% ethanol solution and the absorbance of the extract was measured at 510nm using a spectrophotometer. The method was reproducible and cyanide as low as 1 microgram could be determined. Cyanide levels of all the cassava varieties tested were higher than the 10ppm WHO safe level. Recovery of cyanide from acyanogenic foods fortified at levels of 5 and 10mg KCN/10g were 98.6% and 99.1% respectively. The picrate method is simple and useful for routine determination of cyanide content of cassava flour.Keywords: Picrate method, Cyanide, Cassava flour

Fireground Use of an Emergency Escape Respirator

Introduction. Firefighters who become lost, disoriented, or trapped in a burning building may die after running out of air in their self-contained breathing apparatus (SCBA). An emergency escape device has been developed that attaches to the firefighter's mask in place of the SCBA regulator. The device filters out particulate matter and a number of hazardous components of smoke (but does not provide oxygen), providing additional time to escape after the firefighter runs out of SCBA air. Objective. To field-test the device under realistic fire conditions to 1) ascertain whether it provides adequate protection from carbon monoxide (CO) and 2) examine firefighters’ impressions of the device and its use. Methods. A wood-frame house was fitted with atmospheric monitors, and levels of CO, oxygen, and hydrogen cyanide were continuously recorded. After informed consent was obtained, firefighters wearing the escape device instead of their usual SCBA regulators entered the burning structure and spent 10 minutes breathing through the device. A breath CO analyzer was used to estimate (±3 ppm) each subject's carboxyhemoglobin level immediately upon exiting the building, vital signs and pulse oximetry were assessed, and each firefighter was asked for general impressions of the device. Results. Thirteen subjects were enrolled (all male, mean age 42.5 years, mean weight 94 kg). The mean peak CO level at the floor in the rooms where the subjects were located was 546 ppm, and ceiling CO measurements ranged from 679 ppm to the meters’ maximum of 1,000 ppm, indicating substantial CO exposure. The firefighters’ mean carboxyhemoglobin level was 1.15% (range 0.8%–2.1%) immediately after exit. All pulse oximetry readings were 95% or greater. No subject reported problems or concerns regarding the device, no symptoms suggestive of smoke inhalation or toxicity were reported, and all subjects expressed interest in carrying the device while on duty. Conclusion. The emergency escape device provides excellent protection from CO in realistic fire scenarios with substantial exposure to toxic gases, and the firefighters studied had a positive impression of the device and its use.

Cyanide in bronchoalveolar lavage is not diagnostic for Pseudomonas aeruginosa in children with cystic fibrosis

Early detection of the cyanobacterium Pseudomonas aeruginosa in the lungs of young children with cystic fibrosis (CF) is considered the key to delaying chronic pulmonary disease. We investigated whether cyanide in bronchoalveolar lavage (BAL) fluid could be used as an early diagnostic biomarker of infection. Cyanide was measured in 226 BAL samples (36 P. aeruginosa infected) obtained from 96 infants and young children with CF participating in an early surveillance programme involving annual BAL. Cyanide was detected in 97.2% of P. aeruginosa infected and 60.5% of uninfected samples. Cyanide concentrations were significantly higher in BALs infected with P. aeruginosa (median (25th-75th percentile) 27.3 (22.1-33.3) μM) than those which were not (17.2 (7.85-23.0) μM, p<0.001). The best sensitivity, specificity, positive and negative predictive values were obtained with a cut-off concentration of 20.6 μM, and were 83%, 66%, 32% and 96%, respectively. Neutrophil number in BAL was a significant predictor of cyanide concentration (p<0.001). Cyanide concentration can distinguish between P. aeruginosa infected and uninfected BALs as a group, but not individually; therefore, cyanide is a poor diagnostic biomarker of P. aeruginosa infection. Cyanide levels in BAL are related to the level of neutrophilic inflammation.

Present or Past Herbivory: A Screening of Volatiles Released from Brassica rapa Under Caterpillar Attacks as Attractants for the Solitary Parasitoid, Cotesia vestalis

Females of the solitary endoparasitoid Cotesia vestalis respond to a blend of volatile organic compounds (VOCs) released from plants infested with larvae of their host, the diamondback moth (Plutella xylostella), which is an important pest insect of cruciferous plants. We investigated the flight response of female parasitoids to the cruciferous plant Brassica rapa, using two-choice tests under laboratory conditions. The parasitoids were more attracted to plants that had been infested for at least 6 hr by the host larvae compared to intact plants, but they did not distinguish between plants infested for only 3 hr and intact plants. Although parasitoids preferred plants 1 and 2 days after herbivory (formerly infested plants) over intact plants they also preferred plants that had been infested for 24 hr over formerly infested plants. This suggests that parasitoids can distinguish between the VOC profiles of currently and formerly infested plants. We screened for differences in VOC emissions among the treatments and found that levels of benzyl cyanide and dimethyl trisulfide significantly decreased after removal of the host larvae, whereas terpenoids and their related compounds continued to be released at high levels. Benzyl cyanide and dimethyl trisulfide attracted parasitoids in a dose-dependent manner, whereas the other compounds were not attractive. These results suggest that nitrile and sulfide compounds temporarily released from plants under attack by host larvae are potentially more effective attractants for this parasitoid than other VOCs that are continuously released by host-damaged plants.

A novel kinetic spectrophotometric method for the determination of ultra trace amount of cyanide

A kinetic spectrophotometric method is described for the determination of trace levels of cyanide based on its catalytic effect on the oxidation of Janus green by ammonium peroxodisulfate in nitric acid media. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of the Janus green at 612 nm after 4 min. The effect of reaction variables on the reaction sensitivity was investigated. Under the optimized conditions, a calibration graph from 10.0 to 500.0 ng/ml of cyanide with a detection limit of 7.0 ng/m was obtained. The proposed method is simple, sensitive and inexpensive and it was applied to directly the determination of cyanide in drinking and ground waters with the satisfactory results.

PENURUNAN KADAR SIANIDA DALAM LIMBAH CAIR TAPIOKA MENGGUNAKAN FOTOKATALIS TiO2

Cyanide compound is one of the organic material contained in wastewater of tapioca production, which is a highly toxic substance for life. According to the results of physical and chemical properties of liquid waste samples of tapioca starch in the deposition process in the industry taken from Pancasan Village, Ajibarang, Banyumas, cyanide concentration in the effluent was 3.8 mg/L while the maximum level of cyanide allowed in industrial wastewater are 0.5 mg/L. Therefore, a method to reduce the concentration of cyanide is needed. One of the method is using of TiO2 catalyst. This study was aimed to determine the effect of the pH and UV irradiation time on photocatalytic activity of TiO2 to reduce the levels of cyanide on tapioca wastewater from PT. HARUM BUNGA, Purbalingga.This study uses a thin layer of TiO2 photocatalyst prepared by suspension of TiO2 coating on the glass plate that was dried at 120ºC and conducted with variations of pH that were 2, 5, 7, 8, 9, 10, and 13 in the wastewater to determine the optimum pH, continued by time variation of UV radiation for 1, 2, 4, 6, 8, 10, and 12 hours. The results showed that the largest percentage decrease in the concentration of cyanide occurs at pH 9 that is equal to 88.6361% and the largest percentage decrease in the concentration of cyanide by irradiation with UV light occurs after 10 hours irradiation, up to 93.7929%.

Response of some metabolic and biochemical indices in rabbits fed varying levels of dietary cyanide

Twenty four growing rabbits were used to assess the response of serummetabolites, performance, nutrient digestibility, and carcass characteristics of rabbits to varying dietary cyanide levels. The animals were randomly allocated to four experimental, isocaloric and isoproteinous diets containing 0mg, 250mg, 500mg and 750mg dietary cyanide levels corresponding to diets 1, 2, 3 and 4 respectively. Animals on diets 2, 3, and 4 had significantly (P

Utilization of Cassava Through Freezing

Investigations were carried out to use cassava in frozen form to increase the consumption among people. Two popular varieties MU 51 and Kirikavadi were used for the study. Heat treatments of blanching and boiling together with packing materials of Low-density polyethylene (LDPE) and Low-density polyethylene and Nylon (LDPE+N) were tested in completely randomized design. Both varieties had a minimum percentage weight loss during storage. Microbiological study showed that all samples were safe for consumption up to 3 months at freezer storage. Cyanide levels were significantly reduced by boiling before freezing. Variety Kirikavadi had significantly lower cyanide levels than variety MU 51. Quick freezing using a modification in a normal freezer showed superior quality of frozen product compared to those of stored in a normal freezer. Both varieties of cassava after boiling for 15 minutes for softening, can quick freeze and then transfer to a normal freezer to maintain the frozen condition. This method can therefore commercially be recommended to utilize cassava for up to 3 months of storage life. Keywords: Cassava; freezing; quality; storage life DOI: 10.4038/jfa.v1i2.1796 Journal of Food and Agriculture Vol.1(2) 2008 pp.17-29

Gold‐Nanocluster‐Based Fluorescent Sensors for Highly Sensitive and Selective Detection of Cyanide in Water

AbstractA novel, gold‐nanocluster‐based fluorescent sensor for cyanide in aqueous solution, which is based on the cyanide etching‐induced fluorescence quenching of gold nanoclusters, is reported. In addition to offering high selectivity due to the unique Elsner reaction between cyanide and the gold atoms of gold nanoclusters, this facile, environmentally friendly and cost‐effective method provides high sensitivity. With this sensor, the lowest concentration to quantify cyanide ions could be down to 200 × 10−9 M, which is approximately 14 times lower than the maximum level (2.7 × 10−6 M) of cyanide in drinking water permitted by the World Health Organization (WHO). Furthermore, several real water samples spiked with cyanide, including local groundwater, tap water, pond water, and lake water, are analyzed using the sensing system, and experimental results show that this fluorescent sensor exhibits excellent recoveries (over 93%). This gold‐nanocluster‐based fluorescent sensor could find applications in highly sensitive and selective detection of cyanide in food, soil, water, and biological samples.

Induction or inhibition of cytochrome P450 2E1 modifies the acute toxicity of acrylonitrile in rats: biochemical evidence

The present study was designed to examine the effects of the inhibition or induction of CYP2E1 activity on acute acrylonitrile (AN) toxicity in rats. Increased or decreased hepatic CYP2E1 activity was achieved by pretreatment with acetone or trans-1,2-dichloroethylene (DCE), respectively. AN (50 mg/kg) was administered by intraperitoneal injection. Onset of convulsions and death were observed in rats with increased CYP2E1 activity, whereas convulsions and death did not appear in rats within 1 h after treatment with AN alone. Convulsions occurred in all AN-treated animals with increased CYP2E1 activity at approximately 18 min. The levels of cyanide (CN(-)), a terminal metabolite of AN, were significantly increased in the brains and livers of the AN-treated rats with increased CYP2E1 activity, compared with the levels in rats treated with AN alone, DCE + AN or acetone + DCE + AN. The cytochrome c oxidase (CcOx) activities in the brains and livers of the rats treated with AN or AN + acetone were significantly lower than those in the normal control rats and the rats treated with DCE, whereas the CcOx activities in the brains and livers of rats with decreased CYP2E1 activity were significantly higher than those in AN-treated rats. Brain lipid peroxidation was enhanced, and the antioxidant capacity was significantly compromised in rats with decreased CYP2E1 activity compared with rats with normal or increased CYP2E1 activity. Therefore, inhibition of CYP2E1 and simultaneous antioxidant therapy should be considered as supplementary therapeutic interventions in acute AN intoxication cases with higher CYP2E1 activity, thus a longer window of opportunity would be got to offer further emergency medication.

The effects of fermentation and boiling on the level of hydrogen cyanide in &lt;i&gt;Mucuna pruriens&lt;/i&gt; (velvet bean)

The effects of fermentation and boiling on the level of hydrogen cyanide in Mucuna pruriens (velvet bean) were investigated. Qualitative phytochemical analysis of Mucuna pruriens revealed the presence that tannins, saponins, cardiac glycosides and cyanogenic glycosides. Quantitative analysis revealed that raw Mucuna pruriens contained 42.10 mg/kg hydrogen cyanide (HCN). The respective fermentation and boiling treatments given to Mucuna pruriens significantly reduced the HCN level in the bean. Fermentation for 4 days reduced the HCN concentration to 8.10 mg/kg (33.25%), while boiling for 60 min reduced it to 26.70 mg/kg (36.38%). Combined 4 days fermentation and 60 min boiling treatments significantly reduced the level of HCN in the bean to 18.85 mg/kg being more effective than its respective fermentation or boiling method in reducing the HCN content by 55.23%. Microorganisms involved in the fermentation were bacteria (Proteus spp, Bacillus spp and Pseudomonas spp) and fungi (Saccharomyces spp, Penicillium spp and Rhizopus, spp). The result showed that a combined 4 days fermentation and 60 minutes boiling treatment was more effective in reducing the level of hydrogen cyanide in Mucuna pruriens to safe levels allowed in human and livestock feeds.Keywords: Boiling, fermentation, hydrogen cyanide, Mucuna pruriens, velvet bean

Intramuscular Cobinamide Sulfite in a Rabbit Model of Sublethal Cyanide Toxicity

Exposure to cyanide in fires and industrial exposures and intentional cyanide poisoning by terrorists leading to mass casualties is an ongoing threat. Current treatments for cyanide poisoning must be administered intravenously, and no rapid treatment methods are available for mass casualty cyanide exposures. Cobinamide is a cobalamin (vitamin B(12)) analog with an extraordinarily high affinity for cyanide that is more water-soluble than cobalamin. We investigate the use of intramuscular cobinamide sulfite to reverse cyanide toxicity-induced physiologic changes in a sublethal cyanide exposure animal model and determine the ability of an intramuscular cobinamide sulfite injection to rapidly reverse the physiologic effects of cyanide toxicity. New Zealand white rabbits were given 10 mg sodium cyanide intravenously over 60 minutes. Quantitative diffuse optical spectroscopy and continuous-wave near-infrared spectroscopy monitoring of tissue oxyhemoglobin and deoxyhemoglobin concentrations were performed concurrently with blood cyanide level measurements and cobinamide levels. Immediately after completion of the cyanide infusion, the rabbits were injected intramuscularly with cobinamide sulfite (n=6) or inactive vehicle (controls, n=5). Intramuscular administration led to rapid mobilization of cobinamide and was extremely effective at reversing the physiologic effects of cyanide on oxyhemoglobin and within deoxyhemoglobin extraction. Recovery time to 63% of their baseline values in the central nervous system occurred within a mean of 1,032 minutes in the control group and 9 minutes in the cobinamide group, with a difference of 1,023 minutes (95% confidence interval 116 to 1,874 minutes). In muscle tissue, recovery times were 76 and 24 minutes, with a difference of 52 minutes (95% confidence interval 7 to 98 minutes). RBC cyanide levels returned toward normal significantly faster in cobinamide sulfite-treated animals than in control animals. Intramuscular cobinamide sulfite rapidly and effectively reverses the physiologic effects of cyanide poisoning, suggesting that a compact cyanide antidote kit can be developed for mass casualty cyanide exposures.

Removal of Cyanogenic Glycoside from Cassava during Controlled Drying

Sweet cassava from the Cook Islands was washed, peeled, and hammer milled. It was spread on metal trays to a thickness of about 2 mm and kept in an enclosed transparent tunnel for 6 h in the sun to encourage endogenous linamarase activity. The end covers were removed and normal solar tunnel drying continued for 2 to 3 days or until quite dry. The temperature of the cassava pulp, the relative humidity in the tunnel, and weight of the cassava pulp were measured at regular intervals. It was found that the temperature of the cassava pulp and relative humidity in the enclosed tunnel rose rapidly to a level that caused the maximum level of linamarase activity. At the end of the 6-h period of fermentation, the total cyanide levels had reduced to well below the 10 ppm on a dry matter basis as recommended by the Codex Alimentarius Commission for food applications of cassava. Solar drying was continued until the moisture content in the product reached a safe level for storage.

Quality of &lt;i&gt;gari&lt;/i&gt; (roasted cassava mash) in Lagos State, Nigeria

Gari is creamy-white, partially gelatinized roasted free flowing granular flour made from cassava roots. It is a major staple consumed in both urban and rural areas due to its convenience. Quality of Gari (roasted cassava mash) in Lagos, Nigeria was investigated. Gari samples were collected at random from different processors and sellers in major urban and rural markets of three-selected local governments in Lagos state. The samples were then analyzed for chemical and functional properties. The cyanide level of gari from Ikorodu and Epe local government areas (excluding that from Epe rural processor) falls within the recommended standard of 20 mg HCN/kg by the Standard Organization of Nigeria (SON). The ash and crude fibre contents of all the samples fall within the standard of 1.5% - 2.0% and the moisture content of all samples (9.73% - 14.87%) falls within the normal range for storage up to seven months. The peak viscosity, ranged from 195.00–373.33 RVU. Badagry rural producer had the highest peak viscosity (at a temperature of 64.05o C in 4.72 minutes) and Ikorodu rural producer had the lowest (at temperature of 64.15oC in 4.40 minutes). The breakdown viscosity ranged from 56.67 RVU – 238.25 RVU with Badagry rural processor gari having the highest and gari from Epe urban processor (Ayetoro) had the lowest. The final viscosity ranged from 195.92-315.33 RVU. Gari from Epe urban processor (Ayetoro) had the highest and that from Ikorodu rural processor had the lowest. The set back viscosity ranged between 47.25 and 101.42 RVU with gari from Gbogbo market of Ikorodu rural area having the highest and that from Poka market of Epe rural area having the lowest. There were significant differences (P

Fetal and maternal lesions of cyanide dosing to pregnant goats

The present work evaluated the pathological effects in both dams and their fetuses of cyanide ingestion during pregnancy using goat as animal model. From the Day 24 of pregnancy, three pregnant goats were dosed by gavage with 3.0 mg KCN/kg bw/day, and two others received only tap water. All dams were euthanized and necropsied at Day 120 of pregnancy. The fetuses were examined carefully for gross abnormalities. Determinations of cyanide and thiocyanate were performed in maternal and fetal blood and in amniotic fluid. Samples of several organs were collected for histopathologic evaluation. No clinical changes were seen in any animal throughout the pregnancy. No malformations or dead fetuses were observed; however, placenta from one treated goat presented increased cotyledon surface area occupied by vascular lumina. Histological lesions in KCN-treated dams consisted of vacuolation of hepatocytes and thyroid follicular cells, increased number of vacuoles on thyroid follicular colloid, and spongiosis of cerebral, internal capsule, and cerebellar peduncles tracts. Fetuses from these mothers showed vacuolation of hepatocytes and thyroid follicular cells, and spheroids in the cerebellar white matter. Levels of cyanide and thiocyanate were higher in maternal than fetal blood, which suggests that these substances were largely but not freely transferred from mothers to fetuses.

Auxin herbicides: current status of mechanism and mode of action

Synthetic compounds that act like phytohormonal 'superauxins' have been among the most successful herbicides used in agriculture for more than 60 years. These so-called auxin herbicides are more stable in planta than the main natural auxin, indole-3-acetic acid (IAA), and show systemic mobility and selective action, preferentially against dicot weeds in cereal crops. They belong to different chemical classes, which include phenoxycarboxylic acids, benzoic acids, pyridinecarboxylic acids, aromatic carboxymethyl derivatives and quinolinecarboxylic acids. The recent identification of receptors for auxin perception and the discovery of a new hormone interaction in signalling between auxin, ethylene and the upregulation of abscisic acid biosynthesis account for a large part of the repertoire of auxin-herbicide-mediated responses, which include growth inhibition, senescence and tissue decay in sensitive dicots. An additional phenomenon is caused by the quinolinecarboxylic acid quinclorac, which also controls grass weeds. Here, the accumulation of phytotoxic levels of tissue cyanide, derived ultimately from quinclorac-stimulated ethylene biosynthesis, plays a key role in eliciting the herbicidal symptoms in sensitive grasses.

Semi‐quantitative tests of cyanide in foods and excreta of Three Hapalemur species in Madagascar

Three sympatric Hapalemur species (H. g. griseus, H. aureus, and H. (Prolemur) simus) in Ranomafana National Park, Madagascar are known to eat bamboo food parts that contain cyanide. How these lemurs avoid cyanide poisoning remains unknown. In this study, we tested for the presence/absence of cyanide in bamboo lemur foods and excreta to (1) document patterns of cyanide consumption among species with respect to diet, (2) identify routes of elimination of cyanide from the gastrointestinal tract, and (3) determine whether cyanide is absorbed from the diet. We tested 102 food, urine, and fecal samples for hydrogen cyanide (HCN) during two "pre-dry" seasons (April 2006, May 2007) using commercially available Cyantesmo test strips. The test strips changed color in the presence of HCN, and we recorded color change on a scale of 0 (no change) to 5 (cobalt) at preset intervals with a final score taken at 24 hr. We detected cyanide in bamboo food parts and urine of all three Hapalemur species. Time to color change of the test strips ranged from almost instantaneous to >12 hr incubation. Of the foods tested, only bamboo contained cyanide, but results differed among bamboo species and plant parts of the same species. Specifically, branch shoot and culm pith of the giant bamboo produced strong, immediate reactions to the test paper, whereas parts of liana bamboos produced either weak or no color change. Cyanide was present in almost all urine samples but rarely in fecal samples. This suggests that dietary cyanide is absorbed in the gastrointestinal tract of the Hapalemur species and excreted, at least in part, by the kidneys. Samples from H. griseus exhibited lower, though still detectable, cyanide levels compared with H. simus and H. aureus. Differences among lemur species appear to be related to the specific bamboo parts consumed.