Seizures in the intrahippocampal kainic acid epilepsy model: characterization using long-term video-EEG monitoring in the rat.

OBJECTIVE: Intrahippocampal injection of kainic acid (KA) in rats evokes a status epilepticus (SE) and leads to spontaneous seizures. However to date, precise electroencephalographic (EEG) and clinical characterization of spontaneous seizures in this epilepsy model using long-term video-EEG monitoring has not been performed. MATERIALS AND METHODS: Rats were implanted with bipolar hippocampal depth electrodes and a cannula for the injection of KA (0.4 lg /0.2 ll) in the right hippocampus. Video-EEG monitoring was used to determine habitual parameters of spontaneous seizures such as seizure frequency, severity, progression and day-night rhythms. RESULTS: Spontaneous seizures were detected in all rats with 13 out of 15 animals displaying seizures during the first eight weeks after SE. A considerable fraction (35%) of the spontaneous seizures did not generalize secondarily. Seizure frequency was quite variable and the majority of the KA treated animals had less than one seizure per day. A circadian rhythm was observed in all rats that showed sufficient seizures per day. CONCLUSIONS: This study shows that the characteristics of spontaneous seizures in the intrahippocampal KA model display many similarities to other SE models and human temporal lobe epilepsy.

Serial day rapid kindling is an effective tool in screening the anti-epileptic properties of topiramate.

INTRODUCTION: In this study, a serial day rapid kindling protocol was used to fully kindle rats in a matter of days. Subsequently, the anticonvulsant profile of a relatively new anti-epileptic drug, topiramate, was evaluated in a cross-over design to further validate this rapid kindling model. METHODS: Rats were kindled during three consecutive days, according to the serial day rapid kindling protocol. Topiramate was tested at a dose of 100mg/kg, i.p., over the next 2 days using a cross-over design. The stability of the kindled state was evaluated in all rats during two retest paradigms. During the drug-testing procedure, rats received a single i.p. injection of either topiramate or verhicle. Starting 1 h later the rats received additional kindling stimulations during which their response was measured. RESULTS: Serial day rapid kindling induced a long lasting and stable fully kindled state that allowed for the anti-epileptic drug screening procedure. Topiramate reduced both the afterdischarge duration and ameliorated seizure semiology in the kindled rats. DISCUSSION: Serial day rapid kindling provided a tool to rapidly kindle rats in 3 days. Using a cross-over design, clear indications on anti-epileptic activity of a given drug can be determined using few laboratory animals.

Cell therapy in models for temporal lobe epilepsy.

For patients with refractory epilepsy it is important to search for alternative treatments. One of these potential treatments could be introducing new cells or modulating endogenous neurogenesis to reconstruct damaged epileptic circuits or to bring neurotransmitter function back into balance. In this review the scientific basis of these cell therapy strategies is discussed and the results are critically evaluated. Research on cell transplantation strategies has mainly been performed in animal models for temporal lobe epilepsy, in which seizure foci or seizure propagation pathways are targeted. Promising results have been obtained, although there remains a lot of debate about the relevance of the animal models, the appropriate target for transplantation, the suitable cell source and the proper time point for transplantation. From the presented studies it should be evident that transplanted cells can survive and sometimes even integrate in an epileptic brain and in a brain that is subjected to epileptogenic interventions. There is evidence that transplanted cells can partially restore damaged structures and/or release substances that modulate existent or induced hyperexcitability. Even though several studies show encouraging results, more studies need to be done in animal models with spontaneous seizures in order to have a better comparison to the human situation.

Carotid artery aneurysm in human immunodeficiency virus infection.

The case is reported of a patient with human immunodeficiency virus (HIV) infection presenting with isolated headache as the presumed manifestation of a cavernous carotid aneurysm. The relationship between HIV and aneurysms is discussed. Clinicians should be aware of the possibility of carotid aneurysms in HIV-positive patients, even in areas where HIV is not endemic and when no neurological deficit is present. Magnetic resonance imaging is recommended as the initial diagnostic study.