62 research outputs found

    Animations en librairie et en bibliothèque : Quelles synergie ? Quelle complémentarité ?

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    Des pratiques similaires, complémentaires, voire concurrentielles, sont observables dans ces deux lieux du livre. Face aux contraintes propres à chaque métier et aux préjugés tenaces sur les pratiques des uns et des autres, comment bibliothèques et librairies construisent-elles leurs programmes d\u27animation pour répondre à un public exigeant et très sollicité ? Comment pourraient-elles travailler mieux ensemble

    Integrated Multiscale Modeling of the Nervous System: Predicting Changes in Hippocampal Network Activity by a Positive AMPA Receptor Modulator

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    One of the fundamental characteristics of the brain is its hierarchical organization. Scales in both space and time that must be considered when integrating across hierarchies of the nervous system are sufficiently great as to have impeded the development of routine multilevel modeling methodologies. Complex molecular interactions at the level of receptors and channels regulate activity at the level of neurons; interactions between multiple populations of neurons ultimately give rise to complex neural systems function and behavior. This spatial complexity takes place in the context of a composite temporal integration of multiple, different events unfolding at the millisecond, second, minute, hour, and longer time scales. In this study, we present a multiscale modeling methodology that integrates synaptic models into single neuron, and multineuron, network models. We have applied this approach to the specific problem of how changes at the level of kinetic parameters of a receptor-channel model are translated into changes in the temporal firing pattern of a single neuron, and ultimately, changes in the spatiotemporal activity of a network of neurons. These results demonstrate how this powerful methodology can be applied to understand the effects of a given local process within multiple hierarchical levels of the nervous system

    Consolidation of an Olfactory Memory Trace in the Olfactory Bulb Is Required for Learning-Induced Survival of Adult-Born Neurons and Long-Term Memory

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    Background: It has recently been proposed that adult-born neurons in the olfactory bulb, whose survival is modulated by learning, support long-term olfactory memory. However, the mechanism used to select which adult-born neurons following learning will participate in the long-term retention of olfactory information is unknown. We addressed this question by investigating the effect of bulbar consolidation of olfactory learning on memory and neurogenesis. Methodology/Principal Findings: Initially, we used a behavioral ecological approach using adult mice to assess the impact of consolidation on neurogenesis. Using learning paradigms in which consolidation time was varied, we showed that a spaced (across days), but not a massed (within day), learning paradigm increased survival of adult-born neurons and allowed long-term retention of the task. Subsequently, we used a pharmacological approach to block consolidation in the olfactory bulb, consisting in intrabulbar infusion of the protein synthesis inhibitor anisomycin, and found impaired learning and no increase in neurogenesis, while basic olfactory processing and the basal rate of adult-born neuron survival remained unaffected. Taken together these data indicate that survival of adult-born neurons during learning depends on consolidation processes taking place in the olfactory bulb. Conclusion/Significance: We can thus propose a model in which consolidation processes in the olfactory bulb determine both survival of adult-born neurons and long-term olfactory memory. The finding that adult-born neuron survival durin

    The UniProt-GO Annotation database in 2011

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    The GO annotation dataset provided by the UniProt Consortium (GOA: http://www.ebi.ac.uk/GOA) is a comprehensive set of evidenced-based associations between terms from the Gene Ontology resource and UniProtKB proteins. Currently supplying over 100 million annotations to 11 million proteins in more than 360 000 taxa, this resource has increased 2-fold over the last 2 years and has benefited from a wealth of checks to improve annotation correctness and consistency as well as now supplying a greater information content enabled by GO Consortium annotation format developments. Detailed, manual GO annotations obtained from the curation of peer-reviewed papers are directly contributed by all UniProt curators and supplemented with manual and electronic annotations from 36 model organism and domain-focused scientific resources. The inclusion of high-quality, automatic annotation predictions ensures the UniProt GO annotation dataset supplies functional information to a wide range of proteins, including those from poorly characterized, non-model organism species. UniProt GO annotations are freely available in a range of formats accessible by both file downloads and web-based views. In addition, the introduction of a new, normalized file format in 2010 has made for easier handling of the complete UniProt-GOA data se

    Simulation of Postsynaptic Glutamate Receptors Reveals Critical Features of Glutamatergic Transmission

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    Activation of several subtypes of glutamate receptors contributes to changes in postsynaptic calcium concentration at hippocampal synapses, resulting in various types of changes in synaptic strength. Thus, while activation of NMDA receptors has been shown to be critical for long-term potentiation (LTP) and long term depression (LTD) of synaptic transmission, activation of metabotropic glutamate receptors (mGluRs) has been linked to either LTP or LTD. While it is generally admitted that dynamic changes in postsynaptic calcium concentration represent the critical elements to determine the direction and amplitude of the changes in synaptic strength, it has been difficult to quantitatively estimate the relative contribution of the different types of glutamate receptors to these changes under different experimental conditions. Here we present a detailed model of a postsynaptic glutamatergic synapse that incorporates ionotropic and mGluR type I receptors, and we use this model to determine the role of the different receptors to the dynamics of postsynaptic calcium with different patterns of presynaptic activation. Our modeling framework includes glutamate vesicular release and diffusion in the cleft and a glutamate transporter that modulates extracellular glutamate concentration. Our results indicate that the contribution of mGluRs to changes in postsynaptic calcium concentration is minimal under basal stimulation conditions and becomes apparent only at high frequency of stimulation. Furthermore, the location of mGluRs in the postsynaptic membrane is also a critical factor, as activation of distant receptors contributes significantly less to calcium dynamics than more centrally located ones. These results confirm the important role of glutamate transporters and of the localization of mGluRs in postsynaptic sites in their signaling properties, and further strengthen the notion that mGluR activation significantly contributes to postsynaptic calcium dynamics only following high-frequency stimulation. They also provide a new tool to analyze the interactions between metabotropic and ionotropic glutamate receptors

    Rare coding variants in PLCG2, ABI3, and TREM2 implicate microglial-mediated innate immunity in Alzheimer's disease

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    We identified rare coding variants associated with Alzheimer’s disease (AD) in a 3-stage case-control study of 85,133 subjects. In stage 1, 34,174 samples were genotyped using a whole-exome microarray. In stage 2, we tested associated variants (P<1×10-4) in 35,962 independent samples using de novo genotyping and imputed genotypes. In stage 3, an additional 14,997 samples were used to test the most significant stage 2 associations (P<5×10-8) using imputed genotypes. We observed 3 novel genome-wide significant (GWS) AD associated non-synonymous variants; a protective variant in PLCG2 (rs72824905/p.P522R, P=5.38×10-10, OR=0.68, MAFcases=0.0059, MAFcontrols=0.0093), a risk variant in ABI3 (rs616338/p.S209F, P=4.56×10-10, OR=1.43, MAFcases=0.011, MAFcontrols=0.008), and a novel GWS variant in TREM2 (rs143332484/p.R62H, P=1.55×10-14, OR=1.67, MAFcases=0.0143, MAFcontrols=0.0089), a known AD susceptibility gene. These protein-coding changes are in genes highly expressed in microglia and highlight an immune-related protein-protein interaction network enriched for previously identified AD risk genes. These genetic findings provide additional evidence that the microglia-mediated innate immune response contributes directly to AD development

    Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

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    Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

    The SIB Swiss Institute of Bioinformatics' resources: focus on curated databases

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    The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) provides world-class bioinformatics databases, software tools, services and training to the international life science community in academia and industry. These solutions allow life scientists to turn the exponentially growing amount of data into knowledge. Here, we provide an overview of SIB's resources and competence areas, with a strong focus on curated databases and SIB's most popular and widely used resources. In particular, SIB's Bioinformatics resource portal ExPASy features over 150 resources, including UniProtKB/Swiss-Prot, ENZYME, PROSITE, neXtProt, STRING, UniCarbKB, SugarBindDB, SwissRegulon, EPD, arrayMap, Bgee, SWISS-MODEL Repository, OMA, OrthoDB and other databases, which are briefly described in this article

    Plasticité de l'inhibition synaptique au cours du développement et lors de douleurs inflammatoires dans le système nociceptif spinal chez le Rat

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    Les couches superficielles de la corne dorsale de la moelle épinière, et en particulier la lamina II, constituent le premier relais synaptique des informations périphériques nociceptives. Le blocage de la transmission inhibitrice au niveau spinal induit des comportements comparables à ceux observés dans le cas d'allodynie ou d'hyperalgésie, suggérant l'importance de l'inhibition dans la modulation et l'intégration des informations nociceptives. Nos résultats électrophysiologiques, obtenus sur des tranches de moelle épinière, montrent qu'une fraction importante des synapses qui arrivent sur les neurones de la lamina II colibère la glycine et le GABA. Dans les conditions de libération miniature, leur codétection par les récepteurs postsynaptiques GABAA et de la glycine est observée durant les trois premières semaines postnatales. Chez l'adulte, elle peut être révélée en utilisant le diazépam (benzodiazépine) ou l'alloprégnanolone (neurostéroïde), deux modulateurs positifs des récepteurs GABAA, suggérant une localisation extrasynaptique de ces récepteurs. Chez l'animal jeune, mais pas chez l'adulte, nous avons mis en évidence une production tonique endogène de neurostéroïdes (NS) qui renforcent l'inhibition synaptique en favorisant la codétection du GABA et de la glycine et en prolongeant la durée des CPSIm GABAA. Chez l'adulte, la stimulation de la production de NS, ou une inflammation périphérique, entraîne la réapparition des CPSIm mixtes parallèlement à la prolongation des CPSIm GABAA. Ceci démontre la régulation de ce mécanisme au cours du développement et son possible rôle de compensation lors d'une situation d'hyperexcitabilité. Ces travaux mettent en évidence la régulation du niveau d'inhibition synaptique sur les neurones de la lamina II par des mécanismes endogènes, au cours du développement et dans des situations de douleurs inflammatoires aiguës, qui peuvent influencer le transfert des informations douloureuses vers les centres supraspinaux.Cutaneous peripheral nociceptive message are conveyed to the CNS by primary afferent fibers which form their first synaptic contact onto lamina II neurons of the dorsal horn. Blockade of spinal GABAergic and glycinergic transmission is associated with allodynia nd hyperalgesia symptoms. This demonstrates the importance of synaptic inhibition in the modulation and the integration of nociceptive message. Using the patch-clamp technique on transversal spinal cord slices, we characterized inhibitory synaptic currents displayed by lamina II neurons during development and inflammatory situation. We showed that GABA and glycine are co-released from a single vesicle in an important fraction of synapses received by lamina II neurons. Both neurotransmitters are detected by postsynaptic glycine and GABAA receptors during the first three postnatal weeks. In the adult, this co-detection was not observed but was revealed by application of diazepam or allopregnanolone, two positive GABAA receptor modulators, suggesting that these receptors were perisynaptic. In young rat, but not in the adult, a tonic endogenous production of neurosteroids (NS) occurs, which reinforce synaptic inhibition by prolonging GABAA mIPSCs and favoring GABA/glycine co-detection. In the adult, stimulation of the PBR by diazepam induces reappearance of mixed GABA/glycine mIPSCs in parallel with prolongation of GABAA mIPSCs. Together, these results showed that, in lamina II neurons, synaptic inhibition is regulated throughout development through two mechanisms : the change in the synaptic location of GABAA receptors and the regulation of NS production. Interestingly, this production could be reactivated in case of hyperexcitability, for example after peripheral inflammation. Thus, the level of NS may represent a key mechanism by which inhibition can be regulated or recruited in pathological situation.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF
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