[Predictors factors of refractory epilepsy in childhood]. / Les critères prédictifs d'une épilepsie pharmacorésistante chez l'enfant.

The aim of this study is to identify early predictors of refractory epilepsy. From 600 epileptic children followed for at least 2 years in the department of neurology of Charles Nicolle hospital of Tunis, were identified children with refractory epilepsy. Controls were children who responded well to antiepileptic drugs and who were seizure free for at least 2years. We collected anamnestic, clinical, neuropsychological and radiological data for all children. We identified 67 children with refractory epilepsy, representing 11.6% of the initial population. At diagnosis, the average age was 9.16 years. Some factors have been identified as predictors of drug resistance epilepsy: age of onset less than one year, partial and atonic seizure, combination of several types of attacks, presence of mental retardation and pyramidal syndrome, abnormal electroencephalogram especially focal abnormalities, spike, amplitude abnormalities, interhemispheric asymmetry; and resistance to first antiepileptic drug. Symptomatic epilepsy, especially if associated with radiological lesions such as hippocampal sclerosis and structural brain malformations, was highly correlated with drug resistance. Our study suggests that the initial presentation of epilepsy could predict long-term outcome to drug resistance epilepsy if a detailed analysis of anamnestic, clinical and complementary data is established.

Respiratory distress and behavioral changes induced by sodium cyanide in the fresh water TELEOST, Cyprinus carpio (Linnaeus).

An acute toxicity (LC50) test using a static renewal bioassay method was conducted to determine the toxicity of sodium cyanide in freshwater exotic carp, Cyprinus carpio exposed for 96 h to different concentrations of sodium cyanide. The acute toxicity value was found to be 1 mg/L; one third of the LC50 (0.33 mg/L) was selected as the sublethal concentration for subacute studies. Behavioral patterns were observed in lethal (1, 2, 3, and 4 d) and sublethal concentrations (1, 5, 10, and 15 d). Cyprinus carpio in toxic media exhibited irregular, erratic, and darting swimming movements, hyperexcitability, loss of equilibrium, and sinking to the bottom, which might be due to inhibition of cytochrome c oxidase activity and decreased blood pH. The combination of cytotoxic hypoxia with lactate acidosis depresses the central nervous system and myocardium, the most sensitive critical sites for anoxia, resulting in respiratory arrest and death. A decrease in oxygen consumption (-28.36 to -78.28%; -14.22 to -47.25%) was observed at both lethal and sublethal concentrations of sodium cyanide respectively. Fish at the sublethal concentration were found under stress, but that was not fatal.