Sampled voltammetry on an electrode array for the renewal of the electrode surface and the analytical solution during the analysis

International audiencePolarography with dropping mercury electrode has been widely used in electroanalysis. However, the method is less and less employed due to the toxicity of mercury. In this work, we have shown that it is possible to replace the dropping electrode by a working electrode array, allowing the renewal of the electrode surface and of the analytical solution during the analysis. This new concept has been demonstrated on copper analysis. Sampled current voltammetry has been carried out on an electrode array, giving rise to I vs. E curves with a limiting diffusion plateau. The principle can be extended to other electroanalytical methods as exemplified here with differential pulse voltammetry. Linear calibration curves have been obtained with both methods and a limit of detection of 2 × 10−5 mol L−1 has been reached for copper detection by differential pulse voltammetry

First-ever population-based study on status epilepticus in French Island of La Reunion (France) - Incidence and fatality.

International audiencePURPOSE: We aimed to determine the incidence and case-fatality of first-ever status epilepticus (SE) among the general population living in La Reunion Island, a French overseas territory in the Indian Ocean near Madagascar. METHODS: We recruited cases (1st July 2004-30th June 2005) in a population-based manner using neurology, neurosurgery, electroencephalogram, emergency, paediatric and neuroradiology services; emergency medical aid service; emergency and admission service of private and public clinics; neurologists (public and private); private paediatricians and practitioners of various rural hospitals. All cases had an electroencephalogram (EEG) and were assessed by an epileptologist. Standard definition and classification schemes were used. Those with known epilepsy were not part of this analysis. RESULTS: Sixty-five cases (males: n=41, 63.1%) had epileptologist-confirmed SE, with 38.5% (n=25) being >60 years of age. Global incidence rate was 8.52/100 000 (95% confidence interval 6.5-10.5). A bimodal age distribution with high frequency and incidence among young (60 years) (frequency: 40.0%; incidence 35.0/100,000) was observed. We found that 60%, 32.3%, 6.7% had convulsive, partial and non-convulsive SE respectively (1% remained unclassified). Of the cases identified, 44.6%, 38.5%, 16.9% had unprovoked, provoked or cryptogenic seizures respectively. The most important aetiological factors identified included: stroke (27.7%), alcoholism/toxicity (18.5%), cryptogenic (16.9%), infections (10.8%). Mortality was 18.5%. CONCLUSION: The incidence of SE incidence in La Reunion Island was lower than that described elsewhere. The status type was found to be dependent on aetiology and age. The study confirms that SE is more frequent in men and in older adults and is associated with significant short-term case mortality

Observational Astrophysics

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Newly diagnosed epileptic seizures: focus on an elderly population on the French island of Réunion in the Southern Indian Ocean.

International audiencePURPOSE: To describe seizure types and risk factors among elderly people with newly diagnosed epileptic seizures living on La Réunion, a French Island in the Southern Indian Ocean. METHODS: We describe an elderly population with newly diagnosed epileptic seizures using data from the EPIREUN study conducted between July 1, 2004 and June 30, 2005. The methodology is described in detail in the EPIREUN study report (Mignard et al., 2009). KEY FINDINGS: There were 153 single unprovoked seizures (84.1%); their incidence was 278.1 [95% confidence interval (CI) 237.4-325.9] per 100,000. The incidence of newly diagnosed epilepsy was 125.4 (95% CI, 99.1-158.8) per 100,000. Twenty-eight acute symptomatic seizures occurred (15.4%); the incidence was 50.9 (95% CI 35.1-73.7) per 100,000. The annual incidence of newly diagnosed epileptic seizure in the elderly was 330.8 (95% CI 286.1-382.6) per 100,000: 403.0 (95% CI 328.5-494.3) per 100,000 in men and 279.6 (95% CI, 227.4-343.8) per 100,000 in women. Sex had a significant (p = 0.014) effect on incidence: elderly men had a risk ratio of 1.44 compared to women of developing a newly diagnosed epileptic seizure. The etiology of single unprovoked seizure was as follows: stroke, 77 cases (50.3%); cryptogenic, 36 (23.5%); alcoholism, 10 (6.6%); a combination of several causes such as polypathology, 9 (5.9%); degenerative disease, 6 (4.0%); HIV infection, 2 (2.0%), and undetermined causes (2.7%). Most patients (170; 93.4%) were hospitalized, and 110 (60.8%) were treated. Among patients treated, 49 (44.5%) were given sodium valproate, 25 (22.7%) benzodiazepines, 12 (10.9%) phenytoin, 9 (8.2%) lamotrigine, 8 (7.3%) Trileptal, and 7 (6.4%) gabapentin. SIGNIFICANCE: Our findings show that the incidences of newly diagnosed epileptic seizures and newly diagnosed epilepsy were high in the elderly population of La Réunion. These incidences were significantly higher in men than in women. These results may be attributable to the high incidence of cerebrovascular diseases and comorbidities in this population

Newly-diagnosed epileptic seizures in three populations: Geneva (EPIGEN), Martinique (EPIMART), and the Reunion Island (EPIREUN).

International audienceThe objective was to analyse and discuss data from three studies of newly-diagnosed epileptic seizures (provoked and unprovoked) conducted in Geneva, Martinique, and the Reunion Island, in which the same methodology was used. We extracted data from three studies in which the incidence of seizures was estimated and aetiologies identified. Data was extracted and analysed using STATA. Group comparison was performed firstly for each study as a single group, and secondly by considering Martinique and the Reunion Island as an overseas group, in comparison with Geneva, considered as a mainland group. Uncorrected χ(2)was used and statistical significance (two-sided, p=0.05) was determined for each aetiology per cohort. The incidence of newly-diagnosed epileptic seizures per 100,000 was 71.0, 80.6, and 100.4 in Geneva, Martinique, and the Reunion Island, respectively. A bimodal distribution and predominance of generalised seizures was noted. The male to female ratio was higher in Martinique (∼2.0) than other populations (∼1.5). Status epilepticus was noted in Geneva and more so in the Reunion Island. The incidence of provoked seizures per 100,000 was 25.2, 16.4, and 17.7, and for unprovoked seizures was 45.6, 64.1, and 81.2 in Geneva, Martinique, and the Reunion Island, respectively. There was a greater risk of provoked seizures in Geneva relative to the overseas group, which was due to tumours, use of toxic substances, and drug abuse. The risk of unprovoked seizures in Geneva was due to trauma and infections. In Martinique, alcoholism and HIV were foremost factors for provoked and unprovoked seizures, and stroke was an important aetiology in both Martinique (provoked seizures) and the Reunion Island (unprovoked seizures). The risk of provoked seizures was greatest in Geneva and risk of unprovoked seizures was greatest in the Reunion Island. Toxic substances, alcohol, infection, and trauma constituted major factors for epileptic seizures in Geneva, while alcoholism, HIV, and stroke were major factors in the overseas group. Relative eradication of tropical infections has paved a way for the emergence of non-communicable aetiologies (stroke, alcoholism). Males from Martinique demonstrated the greatest risk of epileptic seizures, signifying the importance of alcoholism, HIV, etc. Three steps should follow: follow-up studies (mortality), strong mechanisms for prevention (or control) of risk factors, guidelines on whether to treat or not

TOM20-mediated transfer of Bcl2 from ER to MAM and mitochondria upon induction of apoptosis

International audienceIn this work, we have explored the subcellular localization of Bcl2, a major antiapoptotic protein. In U251 glioma cells, we found that Bcl2 is localized mainly in the ER and is translocated to MAM and mitochondria upon induction of apoptosis; this mitochondrial transfer was not restricted to the demonstrator cell line, even if cell-specific modulations exist. We found that the Bcl2/mitochondria interaction is controlled by TOM20, a protein that belongs to the protein import machinery of the mitochondrial outer membrane. The expression of a small domain of interaction of TOM20 with Bcl2 potentiates its anti-apoptotic properties, which suggests that the Bcl2-TOM20 interaction is proapoptotic. The role of MAM and TOM20 in Bcl2 apoptotic mitochondrial localization and function has been confirmed in a yeast model in which the ER-mitochondria encounter structure (ERMES) complex (required for MAM stability in yeast) has been disrupted. Bcl2-TOM20 interaction is thus an additional player in the control of apoptosis

Sphingolipids distribution at mitochondria-associated membranes (MAM) upon induction of apoptosis.

International audienceThe levels and composition of sphingolipids and related metabolites are altered in aging and common disorders such as diabetes and cancers, as well as in neurodegenerative, cardiovascular, and respiratory diseases. Changes in sphingolipids have been implicated as being an essential step in mitochondria-driven cell death. However, little is known about the precise sphingolipid composition and modulation in mitochondria or related organelles. Here, we used LC-MS/MS to analyze the presence of key components of the ceramide metabolic pathway in vivo and in vitro in purified endoplasmic reticulum (ER), mitochondria-associated membranes (MAM), and mitochondria. Specifically, we analyzed the sphingolipids in the three pathways that generate ceramide: sphinganine in the de novo ceramide pathway, sphingomyelin in the breakdown pathway, and sphingosine in the salvage pathway. We observed sphingolipid profiles in mouse liver, mouse brain, and a human glioma cell line (U251). We analyzed the quantitative and qualitative changes of these sphingolipids during staurosporine (STS)-induced apoptosis in U251 cells. Ceramide, especially C16-ceramide, levels increased during early apoptosis possibly through a conversion from mitochondrial sphinganine and sphingomyelin, but sphingosine and lactosyl- and glucosyl-ceramide levels were unaffected. We also found that ceramide generation is enhanced in mitochondria when sphingomyelin levels are decreased in the MAM. This decrease was associated with an increase in acid sphingomyelinase (ASM) activity in MAM. We conclude that meaningful sphingolipid modifications occur in MAM, the mitochondria, and ER during the early phases of apoptosis