Tiocianato urinário em um grupo populacional com elevada ingestão de glicosídeos cianogênicos / Urinary thiocyanate in populational group with elevated ingestion of cianogenic glycosides

Introdução: A mandioca, Manihot esculenta Crantz, é um importante vegetal comestível na região amazônica que durante o processamento origina ácido cianídrico, podendo acarretar efeitos nocivos ao ser humano e animais. Objetivo: Avaliar a exposição humana ao ácido cianídrico oriundo dos glicosídeos cianogênicos presentes no vegetal, através da determinação dos teores urinários de tiocianato, principal produto de biotransformação do cianeto e seus derivado. Método: Análise espectrofotométrica dos teores urinários de tiocianato. Resultados: A concentração urinária média do metabólito nos indivíduos fumantes foi de 1.215 +/- 0,86mg/L, enquanto que em não fumantes de 0,93 +/- 0,87mg/L. Conclusão: Os resultados obtidos indicam que a exposição humana ao ácido cianídrico neste grupo populacional é semelhante à população geral, bem como, confirma a eficiência dos processos de remoção do ácido cianídrico presentes no vegetal utilizado na culinária do estado do Pará

Epidemiological evidence from Zaire for a dietary etiology of konzo, an upper motor neuron disease

A clear association between seasonal outbreaks of a paralytic disease called konzo and toxic effects from consumption of insufficiently processed bitter cassava roots has been demonstrated in Bandundu region, Zaire. A community-based survey of 6764 inhabitants identified 110 live and 24 dead konzo-affected persons with a history of isolated non-progressive spastic paraparesis of abrupt onset. The start of these annual outbreaks of konzo in 1974 coincided with the completion of a new tarmac road to the capital, which facilitated the transport of cassava and made it the main cash crop. The extensive cassava sales encouraged the consumption by the peasant families of roots that had not been adequately processed; frequent acute cyanide intoxications resulted when the naturally occurring cyanogens in the roots were eaten. The disease mainly appeared in the dry season when there was high consumption of insufficiently processed cassava and the diet lacked supplementary foods with sulfur-containing amino acids which promote cyanide detoxification. These results, which confirm the earlier findings in East Africa, show that, owing to the high cyanide and low sulfur dietary intake, there is an increased risk of konzo outbreaks in cassava-growing areas during periods of adverse agro-economic changes

Serum rhodanese in goitre and calcific pancreatitis of tropics.

Rhodanese is one of the enzymes concerned in the detoxification of cyanide. Cassava intake and consequent cyanide toxicity are incriminated in the pathogenesis of goitre and calcific pancreatitis of tropics. So we studied the activity of rhodanese in these patients. 14 controls, 13 patients with pancreatitis and 12 with goitre were studied. The median (and range) of rhodanese in these groups were 82 (50-144), 110 (64-180) and 71 (22-160) units respectively. The serum rhodanese was significantly higher (P less than 0.05) in patients with pancreatitis when compared to the other groups. There was no significant difference between the serum rhodanese in patients with goitre and the controls. The presence of adequate amounts of rhodanese indicates that goitre and chronic pancreatitis are not produced by impaired cyanide detoxification.