RESUMEN
Tropical Spastic Paraparesis (TSP) in West African contries is countries is caused by combination of excess cyanide from the ingestion of Cassava and a deficiency of the sulphur-containing amino-acids required to detosify the cyanide. Free radical damage to long axons has also been reported to results in damage similar to that seen in Jamaican TSP. To investigate the possibility that these mechanisms may be responsible for Jamican TSP, venous blood from non-smoking blood donors and 22 patients with TSP were analysed for thiocyanate, superoxide dismutase and glutahione. Serum thiocyanate is an index of cyanide exposure. Superoxide dismutase protects against free radical damage, and glutathione in addition to rotecting against free radical damage is ana important sulphur-containing peptiae. Levels of thiocyanate in the patients with TSP were similar to those in control patients. Glutathione was elevated in all the patients, and superoxide dimutase activity was normal. The low levels of thiocyanate suggest that cyanide toxicity is not the primary cause of Jamaican TSP and, in any event, sufficient amounts of sulphur-containing amino-acids are present to detoxify cyanide. Free radical mechanisms ara also unlikely to be responsible for damage to the neurons in thes patients