Dravet syndrome as epileptic encephalopathy: Evidence from long-term course and neuropathology

Dravet syndrome is an epilepsy syndrome of infantile onset, frequently caused by SCN1A mutations or deletions. Its prevalence, long-term evolution in adults and neuropathology are not well known. We identified a series of 22 adult patients, including three adult post-mortem cases with Dravet syndrome. For all patients, we reviewed the clinical history, seizure types and frequency, antiepileptic drugs, cognitive, social and functional outcome and results of investigations. A systematic neuropathology study was performed, with post-mortem material from three adult cases with Dravet syndrome, in comparison with controls and a range of relevant paediatric tissue. Twenty-two adults with Dravet syndrome, 10 female, were included, median age 39 years (range 20–66). SCN1A structural variation was found in 60% of the adult Dravet patients tested, including one post-mortem case with DNA extracted from brain tissue. Novel mutations were described for 11 adult patients; one patient had three SCN1A mutations. Features of Dravet syndrome in adulthood include multiple seizure types despite polytherapy, and age-dependent evolution in seizure semiology and electroencephalographic pattern. Fever sensitivity persisted through adulthood in 11 cases. Neurological decline occurred in adulthood with cognitive and motor deterioration. Dysphagia may develop in or after the fourth decade of life, leading to significant morbidity, or death. The correct diagnosis at an older age made an impact at several levels. Treatment changes improved seizure control even after years of drug resistance in all three cases with sufficient follow-up after drug changes were instituted; better control led to significant improvement in cognitive performance and quality of life in adulthood in two cases. There was no histopathological hallmark feature of Dravet syndrome in this series. Strikingly, there was remarkable preservation of neurons and interneurons in the neocortex and hippocampi of Dravet adult post-mortem cases. Our study provides evidence that Dravet syndrome is at least in part an epileptic encephalopathy

Metapopulation structures affect persistence of predator-prey interactions

1. We investigate the metapopulation dynamics of an extinction-prone host-parasitoid interaction. 2. Single cell host-parasitoid interactions show diverging oscillations resulting in rapid extinction of both host and parasitoid. By linking cells together into metapopulations and controlling for increased availability of resource, persistence time of the trophic interaction is enhanced. 3. Metapopulation persistence is influenced by spatial structure and local demographics. Using nonlinear mixed models, we show that the persistence time of these host-parasitoid metapopulations is determined by habitat size and local within-patch population dynamics. 4. We use a metapopulation model to show how the role of local demographic population structure and habitat size act concomitantly to affect persistence

Resposta de fêmeas de Encarsia formosa Gahan (Hymenoptera: Aphelinidae) aos odores do hospedeiro e da planta-hospedeira em olfatômetro de quatro vias Response of female Encarsia formosa Gahan (Hymenoptera: Aphelinidae) to host and plant-host odors

A crescente importância da mosca-branca Bemisia tabaci raça B (Hemiptera: Aleyrodidae) como praga agrícola tem incentivado a busca de inimigos naturais que possam ser utilizados em programas de controle biológico. Estudou-se a atração de fêmeas de Encarsia formosa (Hymenoptera: Aphelinidae) aos odores emanados pelo seu hospedeiro - a mosca-branca B. tabaci raça B - em plantas de tomate, em olfatômetro de quatro vias. O parasitóide não apresentou atração aos odores da planta de tomate nem ao complexo planta de tomate-ninfas de B. tabaci.<br>The increasing importance of the whitefly Bemisia tabaci race B (Hemiptera: Aleyrodidae) as one of the major agricultural pest of this century, has resulted in a search for natural enemies that can be used in biological control programs. The response of naive females of Encarsia formosa (Hymenoptera: Aphelinidae)to volatiles from its hostspecies: insect (B. tabacci race B) and plant (Lycopersicom esculentum Mill.) were tested using 4-nose olfactometre. Parasitoid was not attracted by neither or insect hostspecies volatile