Vieillissement de l'organisation conceptuelle : accès aux propriétés des objets naturels et fabriqués

21 pagesThe organization of adults' conceptual knowledge relies on three main factors: semantic domain (natural objects or artifacts), type of property (visual or functional), and specificity level (general or distinctive properties). This study aims at evaluating which object properties are the most sensitive to normal aging. Accessibility of properties was assessed in young and old adults as a function of these variables, using a property verification task. In both groups, functional properties were more quickly accessed than visual ones, especially specific properties of artifacts. A particular difficulty for specific visual properties of natural objects appeared with aging, suggesting a common form of decline between normal aging and dementia of Alzheimer type. Results related to aging are discussed in relation to hypotheses of the formation of objects concepts.Les connaissances conceptuelles seraient organisées chez l'adulte par le domaine d'appartenance des objets (naturels ou fabriqués), le type de propriétés (visuelles ou fonctionnelles) et leur niveau de spécificité. Cette recherche vise à évaluer les propriétés les plus sensibles au vieillissement. Leur accessibilité est testée chez des adultes jeunes et âgés en fonction de ces variables, à l'aide d'une épreuve de vérification de propriétés. Dans les deux groupes, les propriétés fonctionnelles sont plus accessibles que les propriétés visuelles, surtout à un niveau spécifique et pour les objets fabriqués. Une difficulté particulière pour les propriétés visuelles spécifiques des objets naturels se manifeste lors du vieillissement, ce qui suggère une forme commune d'altération entre le vieillissement normal et la démence Alzheimer. Les résultats liés au vieillissement sont discutés vis-à-vis des hypothèses de formation des concepts d'objets

La stratégie scanner corps entier systématique (est-elle applicable aux traumatisés graves stables des urgences ?)

Introduction : Le scanner corps entier est utilisé pour établir le bilan lésionnel des traumatisés graves stables. Sa réalisation systématique pour les traumatisés graves stables pauci ou asymptomatiques est controversée. Le but de notre étude est de déterminer si l utilisation du protocole scanner corps entier est appropriée pour cette population. L objectif principal est d évaluer la concordance entre l examen clinique et les résultats scannographiques. Nous souhaitons également préciser les caractéristiques des lésions muettes cliniquement. Méthode : Notre étude observationnelle rétrospective s est déroulée aux urgences traumatologiques du Centre hospitalo-universitaire de Grenoble de janvier 2010 à décembre 2011. Etaient inclus les patients traumatisés graves stables ayant bénéficié d un scanner corps entier. Un médecin relevait à postériori les données générales, cinétiques et cliniques contenues dans le dossier médical, ainsi que les résultats du scanner corps entier. L analyse statistique a été réalisée à l aide des logiciels Statview et Stata. Résultats : 429 patients ont été inclus. L âge moyen était de 36 ans avec 75% d hommes. Les accidents de la voie publique représentaient 52% des traumatismes. Le scanner corps entier retrouvait au moins une lésion pour 55% des patients. Le coefficient de concordance kappa revenait de mauvais à moyen selon les étages. Tous segments confondus, 103 lésions asymptomatiques étaient retrouvées au scanner. Elles étaient globalement peu sévères mais ont mené à des interventions thérapeutiques urgentes dans quelques cas. Seules 3 lésions occultes ont été retrouvées au niveau cérébral. Conclusion : La fréquence des lésions retrouvées est un argument en faveur de la réalisation systématique de la tomodensitométrie corps entier, scanner cérébral mis à part, chez les traumatisés graves stables aux urgences.Introduction: The whole body computed tomography (CT) is usually used for early clinical assessment of major trauma patients. Its systematic implementation for multisystem trauma emergencies without signs of severity is controversial. The aim of our study was to determine whether the use of whole-body CT protocol is appropriate for this population. The main objective is to evaluate the correlation between clinical examination and CT-scan results. We also want to specify the characteristics of clinically silent lesions. Method: This retrospective observational study was conducted in Grenoble s hospital emergency department from January 2010 to December 2011. Were included conscious trauma patients without signs of vital distress who had received a whole-body CT. A doctor filled a posteriori general data forms, retrieving circumstances of trauma and clinical data contained in the medical record, as well as the results of whole-body scan. Statistical analysis was performed using Stata and Statview software. Results: 429 patients were included. The average age was 36 years (+ / -17) with 75 % men. The road accidents accounted for 52 % of injuries. The whole body CT found at least one lesion in 55% of patients. The kappa coefficient of agreement ranged from slight to moderate upon the different segments. All segments together, 103 asymptomatic lesions were found on CT. They were generally mild but led to urgent therapeutic interventions in some cases. Only three occult lesions were found in the brain. Conclusion: The frequency of asymptomatic lesion found is in favor of the systematic implementation of the whole body CT, brain scan aside, in blunt multisystem trauma emergencies.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

Local hyperhemia to heating is impaired in secondary Raynaud's phenomenon

Accurate and sensitive measurement techniques are a key issue in the quantification of the microvascular and endothelial dysfunction in systemic sclerosis (SSc). Thermal hyperhemia comprises two separate mechanisms: an initial peak that is axon reflex mediated; and a sustained plateau phase that is nitric oxide dependent. The main objective of our study was to test whether thermal hyperhemia in patients with SSc differed from that in patients with primary Raynaud's phenomenon (RP) and healthy controls. In a first study, we enrolled 20 patients suffering from SSc, 20 patients with primary RP and 20 healthy volunteers. All subjects were in a fasting state. Post-occlusive hyperhemia, 0.4 mg sublingual nitroglycerin challenge and thermal hyperhemia were performed using laser Doppler flowmetry on the distal pad of the third left finger. In a second study, thermal hyperhemia was performed in 10 patients with rheumatoid arthritis and 10 patients with primary RP. The thermal hyperhemia was dramatically altered in terms of amplitude and kinetics in patients with SSc. Whereas 19 healthy volunteers and 18 patients with primary RP exhibited the classic response, including an initial peak within the first 10 minutes followed by a nadir and a second peak, this occurred only in four of the SSc patients (p < 0.0001). The 10 minutes thermal peak was 43.4 (23.2 to 63), 42.6 (31 to 80.7) and 27 (14.7 to 51.4) mV/mm Hg in the healthy volunteers, primary RP and SSc groups, respectively (p = 0.01), while the 44°C thermal peak was 43.1 (21.3 to 62.1), 42.6 (31.6 to 74.3) and 25.4 (15 to 52.4) mV/mm Hg, respectively (p = 0.01). Thermal hyperhemia was more sensitive and specific than post-occlusive hyperhemia for differentiating SSc from primary RP. In patients with rheumatoid arthritis, thermal hyperhemia was also altered in terms of amplitude. Thermal hyperhemia is dramatically altered in patients with secondary RP in comparison with subjects with primary RP. Further studies are required to determine the mechanisms of this altered response, and whether it may provide additional information in a clinical setting

Persistent resistance to HIV-1 infection in CD4 T cells from exposed uninfected Vietnamese individuals is mediated by entry and post-entry blocks

BACKGROUND: We have previously reported that CD4 T cells from some exposed uninfected (EU) Vietnamese intravenous drug users are relatively resistant to HIV infection in vitro. Here, we further characterized the restriction of viral replication in CD4 T cells from five EUs and assessed its persistence in serial samples. RESULTS: CD4 T cells and/or PBMC sampled during a period of between 2 and 6 years were challenged with replication-competent HIV-1 and other retroviral particles pseudotyped with envelope proteins of various tropisms. CCR5 expression and function in resistant CD4 T cells was evaluated. The step at which HIV-1 replication is restricted was investigated by real-time PCR quantification of HIV-1 reverse transcripts. We identified three patterns of durable HIV-1 restriction in EU CD4 T cells. CD4 T cells from four of the five EU subjects were resistant to HIV-1 R5 infection. In two cases this resistance was associated with low CCR5 surface expression, which was itself associated with heterozygous CCR5 mutations. In the other two cases, CD4 T cells were resistant to HIV-1 R5 infection despite normal CCR5 expression and signaling function, and normal β-chemokine secretion upon CD4 T cell activation. Instead, restriction appeared to be due to enhanced CD4 T cell sensitivity to β-chemokines in these two subjects. In the fifth EU subject the restriction involved post-entry steps of viral replication and affected not only HIV-1 but also other lentiviruses. The restriction was not overcome by a high viral inoculum, suggesting that it was not mediated by a saturable inhibitory factor. CONCLUSION: Various constitutive mechanisms of CD4 T cell resistance to HIV-1 infection, affecting entry or post-entry steps of viral replication, are associated with resistance to HIV-1 in subjects who remain uninfected despite long-term high-risk behavior

Comprehensive analysis of current approaches to inhibit regulatory T cells in cancer

CD4+CD25+Foxp3+ regulatory T cells (Treg) have emerged as a dominant T cell population inhibiting anti-tumor effector T cells. Initial strategies used for Treg-depletion (cyclophosphamide, anti-CD25 mAb…) also targeted activated T cells, as they share many phenotypic markers. Current, ameliorated approaches to inhibit Treg aim to either block their function or their migration to lymph nodes and the tumor microenvironment. Various drugs originally developed for other therapeutic indications (anti-angiogenic molecules, tyrosine kinase inhibitors,etc) have recently been discovered to inhibit Treg. These approaches are expected to be rapidly translated to clinical applications for therapeutic use in combination with immunomodulators

Practical guidelines for early screening and field evaluation of banana against Fusarium wilt, Pseudocercospora leaf spots and drought

Practical guidelines for the early screening and field evaluation of banana (Musa spp.) for resistance to three major traits: Fusarium wilt (Fusarium oxysporum f. sp. cubense), leaf spot diseases (Pseudocercospora spp.) and drought. The guidelines have been produced by experts from the Evaluation Thematic Group of MusaNet, the global network for Musa genetic resources (www.musanet.org) coordinated by the Alliance of Bioversity and CIAT

Practical guidelines for early screening and field evaluation of banana against Fusarium wilt, Pseudocercospora leaf spots and drought

Practical guidelines for the early screening and field evaluation of banana (Musa spp.) for resistance to three major traits: Fusarium wilt (Fusarium oxysporum f. sp. cubense), leaf spot diseases (Pseudocercospora spp.) and drought. The guidelines have been produced by experts from the Evaluation Thematic Group of MusaNet, the global network for Musa genetic resources (www.musanet.org) coordinated by the Alliance of Bioversity and CIAT

Mutations in Eml1 lead to ectopic progenitors and neuronal heterotopia in mouse and human.

Neuronal migration disorders such as lissencephaly and subcortical band heterotopia are associated with epilepsy and intellectual disability. DCX, PAFAH1B1 and TUBA1A are mutated in these disorders; however, corresponding mouse mutants do not show heterotopic neurons in the neocortex. In contrast, spontaneously arisen HeCo mice display this phenotype, and our study revealed that misplaced apical progenitors contribute to heterotopia formation. While HeCo neurons migrated at the same speed as wild type, abnormally distributed dividing progenitors were found throughout the cortical wall from embryonic day 13. We identified Eml1, encoding a microtubule-associated protein, as the gene mutated in HeCo mice. Full-length transcripts were lacking as a result of a retrotransposon insertion in an intron. Eml1 knockdown mimicked the HeCo progenitor phenotype and reexpression rescued it. We further found EML1 to be mutated in ribbon-like heterotopia in humans. Our data link abnormal spindle orientations, ectopic progenitors and severe heterotopia in mouse and human