Southern African Large Telescope Spectroscopy of BL Lacs for the CTA project

In the last two decades, very-high-energy gamma-ray astronomy has reached maturity: over 200 sources have been detected, both Galactic and extragalactic, by ground-based experiments. At present, Active Galactic Nuclei (AGN) make up about 40% of the more than 200 sources detected at very high energies with ground-based telescopes, the majority of which are blazars, i.e. their jets are closely aligned with the line of sight to Earth and three quarters of which are classified as high-frequency peaked BL Lac objects. One challenge to studies of the cosmological evolution of BL Lacs is the difficulty of obtaining redshifts from their nearly featureless, continuum-dominated spectra. It is expected that a significant fraction of the AGN to be detected with the future Cherenkov Telescope Array (CTA) observatory will have no spectroscopic redshifts, compromising the reliability of BL Lac population studies, particularly of their cosmic evolution. We started an effort in 2019 to measure the redshifts of a large fraction of the AGN that are likely to be detected with CTA, using the Southern African Large Telescope (SALT). In this contribution, we present two results from an on-going SALT program focused on the determination of BL Lac object redshifts that will be relevant for the CTA observatory

La psychiatrie publique : entre sacrifice et initiation

Certains séjours prolongés en hôpital psychiatrique ne s’expliquent pas par la psychopathologie particulière des patients. Pour le comprendre, il faut analyser les conditions dans lesquelles ils ont été exclus de leur milieu de vie. Ce processus s’apparente à à une démarche sacrificielle, où la violence mimétique est à la fois agie et niée. La victime émissaire ne peut alors se représenter le mécanisme dont elle est l’objet et auquel pourtant elle participe activement. S’appuyant sur les analyses de R. Girard, l’auteur donne quelques exemples de ces mécanismes impitoyables, auxquels seule une pratique initiatique peut s’opposer.Leray Gilles. La psychiatrie publique : entre sacrifice et initiation. In: Chimères. Revue des schizoanalyses, N°16, été 1992. Trop près, trop loin. pp. 47-66

A new treatment era in multiple sclerosis: Clinical applications of new concepts

International audienceSeveral clinical courses have been defined in multiple sclerosis (MS), but uncertainty remains as to whether they reflect different neuropathological mechanisms. Two recent concepts have emerged which could influence the treatment strategy adopted in MS:inflammation drives axonal damage;disability progression in MS follows a two-stage process

Propensity score methods The study of the effect of beta-interferon and glatiramer acetate on multiple sclerosis disability

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Hommage à Michel Crozon

Notre collègue Michel Crozon nous a quittés il y a plus d’un an, le 11 janvier 2008 : nous sommes très nombreux à regretter cette disparition trop soudaine, car la place qu’il occupait dans notre communauté était vraiment unique. La SFP tient particulièrement à rendre hommage à ce physicien de talent qui, outre ses travaux de grande qualité dans le domaine de la physique expérimentale des particules, a consacré beaucoup de son temps à rendre son savoir accessible au grand public et tout spécialement aux enfants. Nous donnons ici la parole à plusieurs de ses collègues et complices, qui témoignent de son engagement

Long-term safety profile of mitoxantrone in a French cohort of 802 multiple sclerosis patients: A 5-year prospective study

International audienceBackground: From 2001, a French multicentre study was conducted prospectively in a large cohort of MS patients and annually updated up to at least 5 years after initiation of MITOX therapy. Objective: To determine long-term safety profile of mitoxantrone (MITOX) in multiple sclerosis (MS).Methods: Eight hundred and two patients from 12 MS centres (308 relapsing-remitting, 352 secondary progressive and 142 primary progressive) received MITOX monthly for 6 months (87%) or every 3 months (13%). Patients underwent clinical and haematologic evaluations before every MITOX infusion and every 6-12 months up to 5 years after MITOX start. Echocardiograms were performed at the start and end of MITOX and up to 5 years after.Results: The cohort was followed for 5354 patient-years (mean). One out of 802 patients (0.1%) presented with acute congestive heart failure and 39 out of 794 patients (4.9%) presented with asymptomatic left ventricular ejection fraction reduction under 50% (persistent in 11 patients (28%), transient in 27 patients (69%), on the last scan at year 5 in 1 patient). Two cases of therapy-related leukaemia (0.25%) were detected 20 months after MITOX start (one death and one with 8 years confirmed remission). Of the 317 women treated before the age of 45, 17.3% developed a persistent age-dependant amenorrhea. Conclusion: This large cohort with at least 5 years of follow-up provided good insights into the long-term safety profile of MITOX in MS

An excessive risk of suicide may no longer be a reality for multiple sclerosis patients

International audienceBACKGROUND: Few recent studies have shown that there is no longer an increased risk of suicide in patients affected with multiple sclerosis (MS). OBJECTIVES: To describe suicide cases within a large French MS cohort and assess whether MS patients are at a higher risk of suicide compared with the general population. METHODS: Data derives from a study on long-term mortality of 27,603 prevalent cases from 15 MS specialist centres. Of 1,569 deceased MS patients (5.7%) on 1 January 2010, 47 were suicides. RESULTS: The mean time between MS clinical onset and death was 13.5 years (standard deviation (SD): 9.3 years; none within the first 3 years) and was significantly shorter than for MS patients who had died from other causes (mean = 21.4 (SD = 11.6), p < 0.0001). Age at death was also lower (46.3 vs 56.7). The standardized mortality rates were around 1 in several sensitivity analyses, reflecting no excess mortality in MS compared with general population. CONCLUSION: Our findings indicate that an excess suicide risk may no longer be true for MS patients and highlight the changing profile of cases, occurring later in the disease course. Further studies in population-based registries are needed to confirm and explain these potential changes (e.g. treatments' impact?)

Algorithmes neuronaux et non-neuronaux de construction de dictionnaire pour la quantification vectorielle en traitement d'images

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Epidemiology of multiple sclerosis

International audienceMultiple sclerosis (MS) is the most frequently seen demyelinating disease, with a prevalence that varies considerably, from high levels in North America and Europe (&gt; 100/100,000 inhabitants) to low rates in Eastern Asia and sub-Saharan Africa (2/100,000 population). Knowledge of the geographical distribution of the disease and its survival data, and a better understanding of the natural history of the disease, have improved our understanding of the respective roles of endogenous and exogenous causes of MS. Concerning mortality, in a large French cohort of 27,603 patients, there was no difference between MS patients and controls in the first 20 years of the disease, although life expectancy was reduced by 6–7 years in MS patients. In 2004, the prevalence of MS in France was 94.7/100,000 population, according to data from the French National Health Insurance Agency for Salaried Workers (Caisse nationale d’assurance maladie des travailleurs Salariés [CNAM-TS]), which insures 87% of the French population. This prevalence was higher in the North and East of France. In several countries, including France, the gender ratio for MS incidence (women/men) went from 2/1 to 3/1 from the 1950s to the 2000s, but only for the relapsing–remitting form. As for risk factors of MS, the most pertinent environmental factors are infection with Epstein-Barr virus (EBV), especially if it arises after childhood and is symptomatic. The role of smoking in MS risk has been confirmed, but is modest. In contrast, vaccines, stress, traumatic events and allergies have not been identified as risk factors, while the involvement of vitamin D has yet to be confirmed. From a genetic point of view, the association between HLA-DRB1*15:01 and a high risk of MS has been known for decades. More recently, immunogenetic markers have been identified (IL2RA, IL7RA) and, in particular thanks to studies of genome-wide associations, more than 100 genetic variants have been reported. Most of these are involved in the immune response and often associated with other autoimmune diseases. Studies of the natural history of MS suggest it is a two-phase disease: in the first phase, inflammation is focal with flares; and in the second phase, disability progresses independently of focal inflammation. This has clear implications for therapy. Age may also be a key factor in the phenotype of the disease. In conclusion, France is a high-risk country for MS, but it only slightly reduces life expectancy. MS is a multifactorial disease and the implications of immunogenetics are major. Preventative approaches might be derived from knowledge of the risk factors and natural history of the disease (smoking, vitamin D