Modulation of absence seizures by branched-chain amino acids: correlation with brain amino acid concentrations.

The occurrence of absence seizures might be due to a disturbance of the balance between excitatory and inhibitory neurotransmissions in the thalamo-cortical loop. In this study, we explored the consequences of buffering the glutamate content of brain cells on the occurrence and duration of seizures in Genetic Absence Epilepsy Rats from Strasbourg (GAERS), a genetic model of generalized non-convulsive epilepsy. Branched-chain amino acids (BCAAs) and alpha-ketoisocaproate (alpha-KIC), the ketoacid of leucine were repeatedly shown to have a critical role in brain glutamate metabolism. Thus, GAERS were injected by intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) route with these compounds, then the effects on seizures were evaluated on the electroencephalographic recording. We also measured the concentration of amino acids in thalamus and cortex after an i.p. injection of leucine or alpha-KIC. Intracerebroventricular injections of leucine or alpha-KIC did not influence the occurrence of seizures, possibly because the substances reached only the cortex. BCAAs and alpha-KIC, injected intraperitoneally, increased the number of seizures whereas they had only a slight effect on their duration. Leucine and alpha-KIC decreased the concentration of glutamate in thalamus and cortex without affecting GABA concentrations. Thus, BCAAs and alpha-KIC, by decreasing the effects of glutamatergic neurotransmission could facilitate those of GABAergic neurotransmission, which is known to increase the occurrence of seizures in GAERS.

Clinical and electroencephalographic characteristics of children with febrile seizures plus.

OBJECTIVES: Febrile seizures plus (FS+) are attracting attention for their corresponding genetic abnormalities, and are defined as febrile seizures (FS) continuing beyond 6 years of age (late FS) or those associated with afebrile seizures. We tried to elucidate their clinical and EEG characteristics as compared with those of children having only FS. SUBJECTS AND METHODS: We reviewed clinical records in a pediatric neurology clinic to identify 31 patients with FS+ (group FS+) and 51 with only FS (group FS). Their family history of seizures, clinical features and EEG findings were compared. RESULTS: A family history of seizures was noted in 14 patients (45.2%) of group FS+ and in 24 (47.1%) of group FS. In group FS+, 19 patients had late FS, 11 had afebrile seizures, and the remaining one had both types of seizures. Two patients had seizures induced by TV/video-game as well, and another suffered from absences. Epileptic EEG abnormalities, which included diffuse spike-waves and focal spikes, were noted in 13 patients (41.9%) of group FS+ and 12 (23.5%) of group FS. CONCLUSIONS: The clinical and EEG characteristics of the children having FS+ were diverse, without significant differences from those with FS except for the seizures types.

Características clínicas de las ausencias infantiles

Se realizó un estudio retrospectivo para evaluar el cuadro clínico, hallazgos electroencefalográficos y tratamiento de pacientes con diagnóstico de ausencias infantiles, registrados en el Servicio de Neurología Infantil del Hospital Militar Central de Santafé de Bogotá, durante el período de enero de 1987 a enero de 1993. Este estudio analiza 23 pacientes con edades de cuatro a 12 años; se observó un predominio del sexo femenino en relación con el masculino de 2:1. Las crisis de ausencias típicas estuvieron presentes en el 50 por ciento de los pacientes; el examen neurológico fue normal en todos los pacientes y ninguno de los pacientes presentaba retardo mental, el electroencefalograma característico de punta onda lenta de tres ciclos por segundo estuvo presente en el 50 por ciento de los pacientes. Se utilizó monoterapia con drogas anticonvulsivantes (valproato sódico o etosuccimida) en 22 de los niños y un paciente no recibió tratamiento. La respuesta terapéutica fue satisfactoria.