Medulloblastomas with ELP1 pathogenic variants: A weakly penetrant syndrome with a restricted spectrum in a limited age window

Background: ELP1 pathogenic variants (PV) have been recently identified as the most frequent variants predisposing to Sonic Hedgehog (SHH) medulloblastomas (MB); however, guidelines are still lacking for genetic counseling in this new syndrome. Methods: We retrospectively reviewed clinical and genetic data of a French series of 29 ELP1-mutated MB. Results: All patients developed SHH-MB, with a biallelic inactivation of PTCH1 found in 24 tumors. Other recurrent alterations encompassed the TP53 pathway and activation of MYCN/MYCL signaling. The median age at diagnosis was 7.3 years (range: 3-14). ELP1-mutated MB behave as sporadic cases, with similar distribution within clinical and molecular risk groups and similar outcomes (5 y - OS=86%); no unusual side effect of treatments was noticed. Remarkably, a germline ELP1 PV was identified in all patients with available constitutional DNA (n=26); moreover, all tested familial trio (n=11) revealed that the PVs were inherited. Two of the 26 index cases from the French series had a family history of MB; pedigrees from these patients and from 1 additional Dutch family suggested a weak penetrance. Apart from MB, no cancer was associated with ELP1 PVs; second tumors reported in 4 patients occurred within the irradiation fields, in the usual time-lapse for expected radiotherapy-induced neoplasms. Conclusions: The low penetrance, the "at risk' age window limited to childhood and the narrow tumor spectrum, question the actual benefit of genetic screening in these patients and their family. Our results suggest restricting ELP1 germline sequencing to patients with SHH-MB, depending on the parents"request

La maladie pieds-mains-bouche, de l'épidémie asiatique au développement d'un arsenal thérapeutique innovant en Chine

AIX-MARSEILLE2-BU Pharmacie (130552105) / SudocSudocFranceF

Evaluation du test "Hyplex Staphylo Resist" par comparaison avec des méthodes classiques d'identification du genre Staphylococcus

AIX-MARSEILLE2-BU Pharmacie (130552105) / SudocSudocFranceF

Recherche et caractérisation de nouveaux microorganismes intracellulaires d'amibes dans l'environnement

Les amibes sont des protozoaires unicellulaires représentés de manière ubiquitaire dans l environnement. Plusieurs études ont déjà montré que certains microorganismes, bactéries ou virus, ont la capacité d entrer dans les amibes et de s y multiplier au lieu d y être digérés. Ces microorganismes, qui échappent aux mécanismes de phagocytose, sont par analogie entre l amibe et le macrophage, des pathogènes humains potentiels. Le plus connu et le plus étudié d entre eux est Legionella pneumophila dont la relation étroite avec les amibes a été montrée comme étant un facteur augmentant la pathogénicité de la bactérie, mais aussi le risque de prolifération et de contamination. D autres types de microorganismes ont également été isolés dans l eau, et ont montré la même capacité à se multiplier dans les amibes. Afin d isoler de manière spécifique les microorganismes ayant cette propriété, des méthodes de co-culture sur amibes ont été mises au point. Il s agit d inoculer des échantillons d eau sur des cultures cellulaires pures d amibes axénisées. Ainsi, les bactéries capables de résister aux mécanismes de la phagocytose par les amibes peuvent être isolées, les autres sont digérées par le protozoaire. Cette technique a déjà permis d isoler de nombreux types de microorganismes différents, dans différents types d eau, principalement des réseaux d eau potable. Dans cette étude, nous avons dans un premier temps recherché, au moyen de cette technique de co-culture, de nouveaux microorganismes associés aux amibes dans des eaux de l environnement humain (puits, cours d eau, lacs, fontaines ). En effet, la co-culture est un bon outil permettant de sélectionner de nouvelles espèces bactériennes qui ne sont pas capables de se multiplier en dehors des amibes. Nous avons ainsi pu isoler plusieurs nouvelles espèces de bactéries. Dans un deuxième temps, nous nous sommes plus précisément intéressés au milieu très particulier des tours aéro-réfrigérantes. En effet, dans l environnement, très peu de Légionelles ont pu être trouvées, alors qu elles se multiplient facilement dans ce type d installations. Nous avons donc cherché, toujours au moyen de co-cultures, à isoler de nouveaux microorganismes intracellulaires d amibes dans ce milieu favorisant la prolifération de bactéries et de virus qui se retrouvent plus rarement dans la nature. Nous avons ainsi pu isoler de nouveaux genres et de nouvelles espèces 4 de microorganismes : un virus géant et un virophage (Mamavirus et Sputnik), une nouvelle espèce de virus géant (Marseille virus), un nouveau genre de bactérie intracellulaire stricte (Candidatus Babela massiliensis gen. nov., sp. nov.) et un nouveau genre de bactérie intracellulaire facultative (Reyranella massiliensis gen. nov., sp. nov.). Par ailleurs, dans plusieurs installations, nous avons constaté la présence de nombreuses Mycobacterium sp., dont certaines sont des pathogènes humains déjà reconnus. Ces résultats suggèrent que le risque microbiologique associé aux tours aéro-réfrigérantes ne se limite pas au risque Légionelles , et soulève le problème des autres microorganismes potentiellement pathogènes qui se multiplient également de manière préférentielle dans ce type d installation. Par ailleurs, la grande variété des microorganismes retrouvés au moyen des amibes montre que ces dernières peuvent être un important carrefour de rencontre de différents types de microorganismes, et le lieu d échanges génétiques pouvant aboutir à la création de nouvelles espèces, notamment de virus géants.Free living amoeba are ubiquitous and have been isolated worldwild in the environment. Several studies showed that many microorganisms, bacteria or viruses, are able to enter the amoeba and multiply within the cell. Those kind of microorganisms are potentially human pathogens, as they may act the same way in human macrophages. The most studied is Legionella pneumophila. It s tight relationship to amoeba was demonstrated as a factor of pathogenicity, proliferation and dissemination of the bacteria. After, other types of microorganisms were isolated in water and had the same property. In order to isolate those amoeba-resisting microorganisms, co-culture methods were done. Water samples are inoculated onto an amoebal axenic monolayer. We can by this way specifically isolate the microorganisms that are able to resist amoebal phagocytosis, and the other are digested by the amoeba. This method already allowed isolating several new species of microorganisms, principally in potable water. Our study focuses first on the research of new amoeba-associated microorganisms in environmental water, and allowed us to isolate several new species of bacteria. However, almost no Legionnella were found. In a second part, we focused specifically on cooling-towers, which represent a favorable middle for Legionella sp. proliferation. We looked specifically for new species of microorganisms, bacteria or virus, which could multiply the same way in this kind of installations. During this study, we could isolate several new microorganisms: a new giant virus Mamavirus and a virophage Sputnik; a new giant virus Marseille virus; a new strictly intracellular bacteria, Candidatus Babela massiliensis gen. nov., sp. nov.; and a new facultative intracellular bacteria, Reyranella massiliensis gen. nov., sp. nov. Our results confirm first that co-culture with amoeba is a very good tool to isolate new genus and new species of bacteria, which cannot be isolated with classical methods. Second, they highlight the problem of the microbiological development in cooling towers. Indeed, control is principally focused on the level of Legionella sp., while many other pathogens can be found in these installations. Moreover, many different types of microorganisms could be isolated, using amoebas. It suggests that amoeba, naturally present world wild, can be a natural crossroad for meetings between several microorganisms, and can be the center of genetic exchanges that could lead to the creation of new microorganisms, principally giant viruses.AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocSudocFranceF

La dépression post-partum et ses conséquences chez le nourrisson et le jeune enfant (à partir d'une expérience de médecine générale)

La dépression du post-partum concerne 10 à 20% des jeunes mères. Seule une faible proportion est diagnostiquée et traitée de façon pertinente. Nombreuses sont les mères qui ne consultent pas directement pour leur mal-être et qui viennent en consultation de façon détournée. Les divers motifs de consultations pour nourrissons s avèrent très souvent être des signaux d alarmes, que nous, médecins de soins primaires en particulier, devons saisir. C est en ce sens que l impact de la dépression postnatale sur l enfant et le nourrisson en particulier, mérite d être étudiée. Tous les auteurs s accordent à dire qu il existe des effets de cette dépression sur le développement cognitif, comportemental, émotionnel mais aussi psychosomatique de l enfant. Il ne faut cependant pas considérer l impact de la dépression du post-partum comme un déterminisme simple et linéaire mais l approcher en termes de facteur de risque. Un nouveau concept mérite alors de naître : celui de trouble de la relation mère/enfant.The post-partum depression concerns 10-20 % of the young mothers. Only a small fraction of these is diagnosed and treated appropriately. Many mothers do not seek direct consultation for their malaise but may do so indirectly. We as primary care doctors must be attentive to signals of alarms which can often be read from the various motives of consultations for new-born babies. It is in this sense that the impact of postnatal depression on the child and the new-born baby in particular is worth studying. All authors agree on the fact that this depression may have consequences on the cognitive, behavioural and emotional development as well as on the psychosomatics of the child. The impact of a post-partum depression on the child should not be considered in terms of a simple and linear determinism but should be viewed instead as a risk factor. Further, a new concept needs to be defined: that of the mother/child bonding disorder.GRENOBLE1-BU Médecine pharm. (385162101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Compartmentalization in PVC super-phylum: evolution and impact

International audienceBackground: The PVC super-phylum gathers bacteria from seven phyla (Planctomycetes, Verrucomicrobiae, Chlamydiae, Lentisphaera, Poribacteria, OP3, WWE2) presenting different lifestyles, cell plans and environments. Planctomyces and several Verrucomicrobiae exhibit a complex cell plan, with an intracytoplasmic membrane inducing the compartmentalization of the cytoplasm into two regions (pirellulosome and paryphoplasm). The evolution and function of this cell plan is still subject to debate. In this work, we hypothesized that it could play a role in protection of the bacterial DNA, especially against Horizontal Genes Transfers (HGT). Therefore, 64 bacterial genomes belonging to seven different phyla (whose four PVC phyla) were studied. We reconstructed the evolution of the cell plan as precisely as possible, thanks to information obtained by bibliographic study and electronic microscopy. We used a strategy based on comparative phylogenomic in order to determine the part occupied by the horizontal transfers for each studied genomes. Results: Our results show that the bacteria Simkania negevensis (Chlamydiae) and Coraliomargarita akajimensis (Verrucomicrobiae), whose cell plan were unknown before, are compartmentalized, as we can see on the micrographies. This is one of the first indication of the presence of an intracytoplasmic membrane in a Chlamydiae. The proportion of HGT does not seems to be related to the cell plan of bacteria, suggesting that compartmentalization does not induce a protection of bacterial DNA against HGT. Conversely, lifestyle of bacteria seems to impact the ability of bacteria to exchange genes. Conclusions: Our study allows a best reconstruction of the evolution of intracytoplasmic membrane, but this structure seems to have no impact on HGT occurrences

Identification of giant Mimivirus protein functions using RNA interference

International audienceGenomic analysis of giant viruses, such as Mimivirus, has revealed that more than half of the putative genes have no known functions (ORFans). We knocked down Mimivirus genes using short interfering RNA as a proof of concept to determine the functions of giant virus ORFans. As fibers are easy to observe, we targeted a gene encoding a protein absent in a Mimivirus mutant devoid of fibers as well as three genes encoding products identified in a protein concentrate of fibers, including one ORFan and one gene of unknown function. We found that knocking down these four genes was associated with depletion or modification of the fibers. Our strategy of silencing ORFan genes in giant viruses opens a way to identify its complete gene repertoire and may clarify the role of these genes, differentiating between junk DNA and truly used genes. Using this strategy, we were able to annotate four proteins in Mimivirus and 30 homologous proteins in other giant viruses. In addition, we were able to annotate >500 proteins from cellular organisms and 100 from metagenomic databases

First Isolation of a Giant Virus from Wild Hirudo medicinalis Leech: Mimiviridae isolation in Hirudo medicinalis

Giant viruses and amoebae are common in freshwater, where they can coexist with other living multicellular organisms. We screened leeches from the species Hirudo medicinalis for giant viruses. We analyzed five H. medicinalis obtained from Tunisia (3) and France (2). The leeches were decontaminated and then dissected to remove internal parts for co-culture with Acanthamoeba polyphaga. The genomes of isolated viruses were sequenced on a 454 Roche instrument, and a comparative genomics analysis was performed. One Mimivirus was isolated and the strain was named Hirudovirus. The genome assembly generated two scaffolds, which were 1,155,382 and 25,660 base pairs in length. Functional annotations were identified for 47% of the genes, which corresponds to 466 proteins. The presence of Mimividae in the same ecological niche as wild Hirudo may explain the presence of the mimivirus in the digestive tract of the leech, and several studies have already shown that viruses can persist in the digestive tracts of leeches fed contaminated blood. As leeches can be used medically and Mimiviruses have the potential to be an infectious agent in humans, patients treated with leeches should be surveyed to investigate a possible connection