Cyanide dietary

Highly toxic substances, such as cyanides, are sometimes feeding cues and stimulants for specialized insects. For example, instar larvae of the southern armyworm (Spodoptera eridania) strongly prefer cyanogenic foods, such as foliage of the lima bean, a plant with comparatively elevated cyanide content — up to 31 mg/kg in some varieties — in the form of linamurin (Brattsten et al. 1983). Feeding was stimulated in southern army worms at dietary levels up to 508 mg KCN/kg... 

Experimental studies with southern armyworm larvae and thiocyanate — one of the in vivo cyanide metabolites — showed that 5000 mg thiocyanate/kg diet reduced pupation by 77%, completely inhibited oviposition, and reduced adult emergence by 80% (Brattsten et al. 1983), strongly suggesting that thiocyanate poisoning is the primary effect of high dietary cyanide levels in southern army worms. 

Much of the toxicological interest in cyanide relating to mammals has focused on its rapid lethal action. However, its most widely distributed toxicologic problems are due to its toxicity from dietary, industrial, and environmental factors (Way 1981, 1984 Gee 1987 Marrs and Ballantyne 1987 Eisler 1991). Chronic exposure to cyanide is correlated with specific human diseases Nigerian nutritional neuropathy, Leber s optical atrophy, retrobulbar neuritis, pernicious anemia, tobacco amblyopia, cretinism, and ataxic tropical neuropathy (Towill etal. 1978 Way 1981 Sprine etal. 1982 Beminger et al. 1989 Ukhun and Dibie 1989). The effects of chronic cyanide intoxication are confounded by various nutritional factors, such as dietary deficiencies of sulfur-containing amino acids, proteins, and water-soluble vitamins (Way 1981). 

Routes of administration other than dietary ingestion should not be discounted. Livestock found dead near a cyanide disposal site had been drinking surface water runoff from the area that contained up to 365 mg HCN/L (USEPA 1980). The use of cyanide fumigant powder formulations may be... 

Whole blood, 4-45 mg total CN/L Whole body, 7 mg HCN/kg BW Daily dietary intake of 15-31.5 mg hydrogen cyanide from cassava... 

Elzubeir, E.A. and R.H. Davis. 1988a. Effect of dietary sodium nitroprusside as a source of cyanide on the selenium status of chicks given diets of varying selenium concentration. Brit. Poult. Sci. 29 769-777. 

Gomez, G., M.A. Aparicio, and C.C. Willhite. 1988. Relationship between dietary cassava cyanide levels and broiler performance. Nutr. Rep. Inter. 37 63-75. 

Tewe, O.O. 1982. Effect of dietary cyanide on the performance, metabolism and pathology of the African rat (Cricetomys gambianus Waterhouse). Nutr. Rep. Inter. 26 529-536. 

Tewe, 0.0. 1988. Performance, nutrient utilization and cyanide metabolism in African giant rats (Cricetomys gambianus Waterhouse) fed varying dietary levels of cassava peels. Anim. Technol. 39 77-82. 

A chronic oral MRL was not derived because of the limitations of the available studies. Human studies that described dietary exposure to cyanide through consumption of cassava lacked quantitative exposure information. The one available chronic oral study in rats found no treatment related effects (Howard and Hanzel 1955). 

A number of dietary deficiencies may increase the risk of deleterious cyanide effects. Iodine deficiency is involved in the etiology of such thyroid disorders as goiter and cretinism. These disorders may be exacerbated by excess exposure to cyanide (Delange and Ermans 1971 Ermans et al. 1972). Protein deficiencies and vitamin B12, riboflavin and other vitamins and elemental deficiencies may subject people... 

Levels of cyanide and its metabolite thiocyanate in blood serum and plasma, urine, and saliva have been used as indicators of cyanide exposure in humans, particularly in workers at risk of occupational exposures, in smokers or nonsmokers exposed to sidestream or environmental tobacco smoke, in populations exposed to high dietary levels of cyanide, and in other populations with potentially high exposures (see Section 5.6). The correlation between increased cyanide exposure and urinary thiocyanate levels was demonstrated in workers exposed to 6.4-10.3 ppm cyanide in air (El Ghawabi et al. 1975). In another study, blood cyanide concentrations were found to vary from 0.54 to 28.4 pg/100 mL in workers exposed to approximately 0.2-0.8 ppm cyanide in air, and from 0.0 to 14.0 pg/100 mL in control workers... 

Cyanide in the body is biotransformed to thiocyanate quickly. People may also be exposed to thiocyanate from dietary, industrial, and medical sources. The plasma concentration of thiocyanate has also been used as an index of long-term exposure to cigarette smoke (Liu and Yun 1993). Some authors have determined thiocyanate in body fluids as a measure of cyanide exposure, while others measure cyanide concentrations in body fluids as a measure of cyanide exposure. 

Dufour DL. 1988. Dietary cyanide intake and serum thiocyanate levels in Tukanoan Indians in Northwest Amazonia. Am J Phys Anthropol 75 205. 

Jackson LC. 1988. Behavioral effects of chronic sublethal dietary cyanide in an animal model Implications for humans consuming cassava (Manihot esculenta). Hum Biol 60 597-614. 

Jackson LC, Chandler JP, Jackson RT. 1986. Inhibition and adaptation of red cell glucose-6-phosphate dehydrogenase (G6PD) in vivo to chronic sublethal dietary cyanide in an animal model. Hum Biol 58 67-77. 

Osuntokun BO. 1980. A degenerative neuropathy with blindness and chronic cyanide intoxication of dietary origin The evidence in the Nigerians. In Smith RL and Bababunmi EA, eds. Toxicology in the tropics. London Taylor and Francis, 16-52. 

Tewe 00, Maner JH. 1981a. Long-term and carry-over effect of dietary inorganic cyanide (KCN) in the life cycle performance and metabolism of rats. Toxicol Appl Pharmacol 58 1-7. 

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