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National audience; A la suite de l'interdiction des farines animales en alimentation animale, il est nécessaire de mettre au point des procédés simples et économiques pour les valoriser et les décontaminer vis-à-vis de la présence possible de prion pathogène. L'usage des microorganismes est une solution possible. Aussi, des collections de microorganismes capables de croître sur la kératine ou sur des farines animales et sécrétant des protéases capables de dégrader la PrPsc contenue dans les farines animales ont été criblées. Ceci a permis de découvrir trois souches de bactéries thermophiles, isolées de différentes sources chaudes réparties sur la planète, qui sont capables de dégrader la protéine prion infectieuse PrPsc et de croître sur un milieu composé de farines animales. Leur activité protéolytique, de type chymotrypsique pour l'essentiel, est maximale à la température de 60 à 80°C et focalisée sur certaines liaisons peptidiques qui sont nombreuses sur la protéine prion. Leur action découpe ainsi la protéine prion en morceaux plus courts inoffensifs. Les perspectives sont de mettre en oeuvre ces microorganismes thermophiles dont le patrimoine protéolytique permettrait la dégradation des farines animales, actuellement incinérées, et les protéines prions qu’elles renferment.

National audience; A la suite de l'interdiction des farines animales en alimentation animale, il est nécessaire de mettre au point des procédés simples et économiques pour les valoriser et les décontaminer vis-à-vis de la présence possible de prion pathogène. L'usage des microorganismes est une solution possible. Aussi, des collections de microorganismes capables de croître sur la kératine ou sur des farines animales et sécrétant des protéases capables de dégrader la PrPsc contenue dans les farines animales ont été criblées. Ceci a permis de découvrir trois souches de bactéries thermophiles, isolées de différentes sources chaudes réparties sur la planète, qui sont capables de dégrader la protéine prion infectieuse PrPsc et de croître sur un milieu composé de farines animales. Leur activité protéolytique, de type chymotrypsique pour l'essentiel, est maximale à la température de 60 à 80°C et focalisée sur certaines liaisons peptidiques qui sont nombreuses sur la protéine prion. Leur action découpe ainsi la protéine prion en morceaux plus courts inoffensifs. Les perspectives sont de mettre en oeuvre ces microorganismes thermophiles dont le patrimoine protéolytique permettrait la dégradation des farines animales, actuellement incinérées, et les protéines prions qu’elles renferment.

Spinal neurosarcoidosis is rare (0.43 p. 100 of all sarcoidosis) and can be the initial manifestation of the disease. A 43-year-old right handed African man developed a progressive dorsal neck pain, slowly worsened paresthesia weakness in the legs and a gait disturbance. Magnetic resonance imaging (MRI) scan of the cervical and thoracic spinal cord (sagittal T(1)- weighted image) revealed diffuse enlargement of the cord from C2 to T7 with intense intramedullary enhancement from C2 to T3 after administration of contrast material on sagittal T(1)- weighted image. Cranial MRI scan was normal. Radiographs of the chest revealed bilateral symmetric hilar mediastinal lymphadenopathy with no pulmonary infiltrates. Bronchial biopsy demonstrated non caseating granulomas with langerhans giant cells. The serum angiotensin converting enzyme level was elevated. The patient received corticosteroid with good progressive response. His neurologic symptoms improved markedly and twenty months post-treatment MRI showed no abnormality on enhanced T(1)- weighted images. Two years later he had no relapse. Only 6 to 10 p. 100 of patients with neurosarcoidosis have spinal cord involvement, which may account for the first clinical manifestation of the disease. Most patients with neurosarcoidosis have associated extraneurologic abnormalities. The diagnosis is supported usually by extraneurologic biopsies. Spinal cord biopsy needs to be considered on case-by-case basis.

There are two types of diffusion images: so-called "diffusion-weighted" images (DWI) and apparent diffusion coefficient (ADC) images. For certain authors, ADC mapping is crucial for interpreting diffusion images while for others the ADC map adds no further sensitivity or specificity compared with diffusion weighted images. The objective of this work was to determine those situations where ADC mapping modifies image interpretation.T2-weighted and diffusion-weighted (DIF) MRI sequences were acquired in 197 patients with suspected cerebral ischemia (or = 48 hr). For each lesion (239 lesions in the 197 patients), we analyzed MRI interpretation with and without ADC mapping and compared the interpretations with the final diagnosis established on clinical data and complementary explorations.We observed 3 groups. In group A (36% of the lesions), ADC mapping did not change image interpretation. This group was subdivided into 3 subgroups. A1: T2 and DIF weighted images are normal: no lesions and normal ACD map (n = 38 patients); A2: High intensity signal on T2 and low intensity signal on DIF: ischemic sequelae, ADC always increased (n = 32 lesions); A3: T2 normal and high intensity signal on DIF: hyper acute ischemia and ADC always decreased (n = 16 patients) In group B (high intensity signal on T2 and DIF, 54.5% of the lesions), ADC mapping changed the MRI interpretation: there was acute ischemia if the ADC was decreased (n = 113) and "pseudo-ischemic" lesions if the ADC was normal or increased (n = 17 patients). Group C was comprised of 23 lesions with a false negative ADC (9.5%). These lesions were always small recent ischemic lesions (or = 5 mm) with a high intensity signal on DIF and a strictly normal ADC map.ADC mapping was found to be useful in 54.5% of the lesions and should not be considered as solely a research tool but also as a useful tool for routine clinical practice.

L'Agence française de sécurité sanitaire des aliments (AFSSA) a lancé, depuis juillet 1999, comme l'ont souhaité les Ministres à l'occasion de l'installation du Conseil d'administration de l'AFSSA, un travail général d'évaluation scientifique des risques liés à l'alimentation animale. A la suite des deux grandes crises, dont l'origine provient de l'alimentation animale (crise de l'encéphalopathie spongiforme subaiguë (ESB) et crise dioxines), il est apparu important de procéder à un recensement de l'ensemble des questions liées à l'alimentation animale en relation avec la sécurité des aliments et à une analyse des risques dans ce domaine. Le Directeur général de l'Agence française de sécurité sanitaire des aliments a institué un groupe de travail nommé "Alimentation animale et sécurité des aliments" et présidé par le Professeur Dominique Dormont chargé de réaliser cette analyse générale. Ce groupe de travail pourra en outre être saisi pour répondre rapidement à toute demande d'expertise relevant de sa mission, et proposer des projets d'avis ou de recommandations. Le travail de ce groupe doit couvrir l'ensemble des problématiques liées à l'alimentation animale, hors organismes génétiquement modifiés (OGM) et hors alimentation des espèces non destinées à la consommation humaine (animaux de compagnie).

Dural arteriovenous fistulas (dAVFs) can cause cerebral venous hypertension (VHT). The most common mechanism is due to the fact that some dAVFs can drain retrogradelly in cortical (better defined as leptomeningeal) veins (directly or after drainage in a dural sinus) causing venous engorgement and consequently an impairment of the cerebral venous drainage. However, more rarely, dAVFs without a cortical venous drainage can also be responsible for VHT probably due to dAVF shunts causing insufficient antegrade cerebral venous drainage. In addition, dAVFs are often associated with stenosis and/or thrombosis of dural sinus(es) which can worsen the VHT. Raised pressure within the superior sagittal sinus causes impeded cerebrospinal reabsorption in the arachnoid villi allowing increased intracranial pressure. The venous engorgement in the cortical veins can cause a venous congestive encephalopathy analogous to the venous congestive myelopathy of the spinal dural AVFs. Clinically VHT can cause not only symptoms related to increased intracranial pressure but also seizures, neurological deficits, impairment of the cognitive functions and dementia. An important aspect is the risk of hemorrhage in dAVFs with a leptomeningeal venous drainage leading to VHT. Although the term VHT sensu strictu should be used if venous pressure measurements are performed, angiographic criteria for VHT such as delayed circulation time, venous engorgement and abnormal visualization of the cerebral veins are well established. The purpose of our study was to evaluate the angiographic signs of VHT in patients with dAVF and to study the course of the VHT and of the clinical signs of increased intracranial pressure before and after dAVF endovascular treatment. A retrospective chart analysis of 22 patients (13 males, 9 females) ranging in age from 20 to 87 years (mean: 53 ys.) with a dAVF associated with angiographic signs of VHT was performed. Ten dAVFs were located on the transverse/sigmoid sinus(es), 6 on the superior sagittal sinus, 3 on the petro-tentorial incisura, 1 on the inferior petrosal sinus, 1 on the anterior ethmoidal region and 1 on the Galen vein region. All dAVFs had a retrograde leptomeningeal venous drainage. Stenosis or thrombosis of the dural AVF sinus was observed in 17 cases and stenosis or thrombosis of another sinus(es) and/or of the jugular vein in 8 cases. In 11 patients, the angiographic signs of VHT were global affecting the entire cerebral venous drainage and, in the other 11 patients, the VHT was focal. The VHT caused clinical symptoms of increased intracranial pressure in 18 patients. Other clinical findings included: bruit (11 cases), seizures (3 cases), vertigo (3 cases), visual deficits (2 cases) and impairment of cognitive functions (4 cases). Three patients presented hemorrhage (one parenchymal hematoma, one hemorrhagic infarction and one subarachnoid hemorrhage). The 4 patients without clinical symptoms of increased intracranial pressure presented only bruit in 2 cases, bruit and vertigo in 1 case, bruit and hemorrhagic infarction in another one. The dAVFs were treated by endovascular therapy (arterial approach: 3 cases, venous approach: 6 cases and both arterial and venous approach: 13 cases). Endovascular sessions ranged from 1 to 7 (mean: 2.8) for each patient. After the endovascular treatment, in 12 patients with complete occlusion of the dAVF, the disappearance of angiographic signs of VHT and clinical cure were observed. In 8 patients with partial occlusion of the dAVF, the disappearance of angiographic signs of VHT and clinical cure were observed in 4 cases (almost complete dAVF occlusion in 2 cases); in the other 4 cases, only reduction the angiographic signs of VHT and clinical improvement were obtained. In all 16 patients who were clinically cured angiographic signs of VHT disappeared despite the persistence of dAVF shunts as observed in 4 cases. (ABSTRACT TRUNCATED)

To analyse the presurgical evaluation process of mediotemporal lobe epilepsy (MTLE) in relation to electroclinical characteristics of the patients, we reviewed the presurgical data (clinical, EEG, neuropsychological, MRI, FDG-PET and sometimes intracranial EEG) and the post-operative results of 53 consecutive cases treated by antero-medial temporal resection for MTLE (without lesion other than mediotemporal sclerosis). Forty one patients (77 p. 100) had a typical and well-lateralised presentation and were operated without invasive procedure. Twelve patients (23 p. 100) presented less pure data: unusual or absent auras, divergent scalp EEG features (bitemporal, widespread or extratemporal) or absence of MRI-based hippocampal sclerosis or FDG-PET hypometabolism. They were explored by invasive monitoring which confirmed the medial temporal origin of seizures. Outcome (follow-up: 30 months) was excellent in 88 p. 100 of the pure cases (Engel's class I) and less favorable in the more difficult ones (50 p. 100 of class I). In conclusion, the diagnosis and surgical treatment of MTLE can be performed without invasive investigations in the majority of cases owing to the strong contribution of brain imaging and video EEG monitoring. Some patients however present a less pure presentation suggesting more complex epileptogenic networks and associated to relatively less favorable postsurgical results.

Recent developments in animal and humans transmissible spongiform encephalopathies have motivated a study on incidence and risk factors of Creutzfeldt-Jakob disease (CJD) in France and 4 other European countries.CJD cases were ascertained through a national network including 250 neurological departments or neuropathological laboratories. CJD cases were classified as definite, probable or possible. Overall incidence rate and age-standardized incidence rates by department were computed. Standardized incidence ratios and their 95% confidence intervals were computed for comparing observed and expected number of CJD cases in each department.Between 1992 and 1995, 216 CJD cases were registered (mean incidence rate: 0.87 per million inhabitants). The distribution of CJD cases was heterogeneous (p0.007). Nevertheless, the distribution of standardized incidence ratios fitted quite well a Poisson distribution. The observed number of CJD cases was significantly higher than expected in 4 departments and lower in 1 department.Incidence of CJD in France is similar to that observed in other European countries. Analysis of distribution of CJD cases by department showed a few significant differences which can be due to random fluctuations.

Disorders of the nervous system frequently complicate Acquired Immune Deficiency Syndrome (AIDS). They may be related to the development of opportunistic agents (toxoplasmosis, cryptococcossis, cytomegalovirus, JC Virus), or primary CNS lymphoma. There is also a constellation of neurologic disorders which may result from direct Human Immunodeficiency Virus (HIV) replication in the CNS and HIV has been found in brain and CSF of numerous patients suffering from AIDS. The precise cellular localization of HIV is not known, but the macrophage seems to be a strong candidate for HIV replication in CNS.