Is it possible to discriminate odors with common words ?

Several experiments have been performed in order to study the cognitive processes which are involved in odor recognition. The current report summarizes experimental protocol and analyzes collected data. The goal is to try to recognize odors from descriptors which are selected by subjects from a list. Different groups have to choose in several descriptor lists, some with profound descriptors and some with a few surface descriptors. Profound descriptors are supposed to involved more cognition than surface descriptors. Subjects also have to name the odors. Recorded data are first analyzed, and then learned by an incremental neural classifier. The problem is hard to be learned. It seems very difficult to discriminate the different odors from the sets of descriptors. A variant of the learning algorithm, less sensitive to difficult examples, is proposed. The pertinence of surface descriptors is discussed.Des expériences ont été réalisées pour étudier les processus cognitifs impliqués dans la reconnaissance des odeurs. Ce rapport résume le protocole expérimental et étudie les données collectées. Le but est d'essayer de discriminer des odeurs à partir de descripteurs qui sont choisis par les sujets dans une liste. Plusieurs groupes travaillent avec différentes listes de descripteurs, ces descripteurs pouvant être de surface ou profonds. Les descripteurs profonds sont supposés être imliqués dans des traitememts plus cognitifs que les descripteurs de surface. Les sujets doivent également nommer les odeurs. Les données recueillies sont d'abord analysées, puis apprises par un classifieur neuronal incrémental. Le problème est difficile à apprendre. Il semble très délicat de discriminer les odeurs à partir des jeux de descripteurs. Une variante de l'algorithme d'apprentissage, moins sensible aux exemples difficiles, est proposée. La pertinence des descripteurs de surface est discutée

Characterization of Pax3 and Sox10 Transgenic Xenopus Laevis Embryos as Tools to Study Neural Crest Development

The neural crest is a multipotent population of cells that originates a variety of cell types. Many animal models are used to study neural crest induction, migration and differentiation, with amphibians and birds being the most widely used systems. A major technological advance to study neural crest development in mouse, chick and zebrafish has been the generation of transgenic animals in which neural crest specific enhancers/promoters drive the expression of either fluorescent proteins for use as lineage tracers, or modified genes for use in functional studies. Unfortunately, no such transgenic animals currently exist for the amphibians Xenopus laevis and tropicalis, key model systems for studying neural crest development. Here we describe the generation and characterization of two transgenic Xenopus laevis lines, Pax3-GFP and Sox10-GFP, in which GFP is expressed in the pre-migratory and migratory neural crest, respectively. We show that Pax3-GFP could be a powerful tool to study neural crest induction, whereas Sox10-GFP could be used in the study of neural crest migration in living embryos

Renal tubular absorption of β2 microglobulin

Renal tubular absorption of β2 microglobulin. 125Iodinated human β2 microglobulin (β2m, 5 to 30 mg) was administered to anesthetized rats. Clearance studies showed a low threshold of excretion of injected β2m and a high Tm of 400 to 600 µg · min-1 · kg-1. A glomerular sieving coefficient of 0.97 was calculated as the slope of the curve: β2m excretion rate = F (plasma β2m × glomerular filtration rate) for values above saturation. Electrophoresis analysis of proteinuria in agarose gel and sodium dodecyl sulfate polyacrylamide gel showed that injection of saturating doses of β2m induced the excretion of proteins of similar size but different charge and that of other proteins of different size. Among the latter, some were excreted transiently in association with β2m, whereas others had a delayed excretion suggesting existence of a complex mechanism of reabsorption whose steps remain to be elucidated.Absorption tubulaire rénale de la β2 microglobuline. De 5 à30 mg de β2 microglobuline (β2m) humaine marquée à l'Iode 125 ont été injectés à des rats anesthésiés. Des études de clairance ont montré un seuil d'excrétion bas et un Tm élevé de 400 à 600 µg · min-1 · kg-1. Un coefficient de tamisage de 0,97 a été mesuré à partir de la pente de la courbe: excretion de β2m = F (concentration plasmatique de β2m × filtration glomérulaire) pour les points au-dessus de la saturation. L'analyse de la protéinurie par électrophorèse sur gel d'agarose et sur gel de polyacrylamide avec dodecyl-sulfate de sodium a montré que l'injection de doses saturantes de β2m provoque l'excretion de protéines de même taille mais de charge différente, ainsi que de protéines de taille différente. Parmi ces dernières, certaines sont excrétées de manière transitoire et en même temps que la β2m, tandis que d'autres ont une excrétion retardée suggérant l'existence d'un mécanisme de réabsorption complexe dont les étapes restent à étudier

Cotranslational endoplasmic reticulum assembly of FcɛRI controls the formation of functional IgE-binding receptors

The human high affinity receptor for IgE (FcɛRI) is a cell surface structure critical for the pathology of allergic reactions. Human FcɛRI is expressed as a tetramer (αβγ2) on basophils or mast cells and as trimeric (αγ2) complex on antigen-presenting cells. Expression of the human α subunit can be down-regulated by a splice variant of FcɛRIβ (βvar). We demonstrate that FcɛRIα is the core subunit with which the other subunits assemble strictly cotranslationally. In addition to αβγ2 and αγ2, we demonstrate the presence of αβ and αβvarγ2 complexes that are stable in the detergent Brij 96. The role of individual FcɛRI subunits for the formation of functional, immunoglobulin E–binding FcɛRI complexes during endoplasmic reticulum (ER) assembly can be defined as follows: β and γ support ER insertion, signal peptide cleavage and proper N-glycosylation of α, whereas βvar allows accumulation of α protein backbone. We show that assembly of FcɛRI in the ER is a key step for the regulation of surface expression of FcɛRI. The ER quality control system thus regulates the quantity of functional FcɛRI, which in turn controls onset and persistence of allergic reactions

Procalcitonin biomarker kinetics fails to predict treatment response in perioperative abdominal infection with septic shock

International audienceIntroduction: Procalcitonin (PCT) biomarker is suggested to tailor antibiotic therapy in the medical intensive care unit (ICU) but studies in perioperative medicine are scarce. The aim of this study was to determine whether PCT reported thresholds are associated with the initial treatment response in perioperative septic shock secondary to intra-abdominal infection. Methods: This single ICU, observational study included patients with perioperative septic shocks secondary to intra-abdominal infection. Demographics, PCT at days 0, 1, 3, 5, treatment response and outcome were collected. Treatment failure included death related to the initial infection, second source control treatment or a new onset intra-abdominal infection. The primary endpoint was to assess whether PCT thresholds (0.5 ng/ml or a drop from the peak of at least 80%) predict the initial treatment response. Results: We included 101 consecutive cases. Initial treatment failed in 36 patients with a subsequent mortality of 75%. Upon admission, PCT was doubled when treatment ultimately failed (21.7 ng/ml +/- 38.7 vs. 41.7 ng/ml +/- 75.7; P = 0.04). Although 95% of the patients in whom PCT dropped down below 0.5 ng/ml responded to treatment, 50% of the patients in whom PCT remained above 0.5 ng/ml also responded successfully to treatment. Moreover, despite a PCT drop of at least 80%, 40% of patients had treatment failure. Conclusions: In perioperative intra-abdominal infections with shock, PCT decrease to 0.5 ng/ml lacked sensitivity to predict treatment response and its decrease of at least 80% from its peak failed to accurately predict treatment response. Studies in perioperative severe infections are needed before using PCT to tailor antibiotic use in this population

De nouvelles dates 14C pour le gravettien des Pyrénées

International audienceBilan des données chronologiques sur le Gravettien et présentation de nouvelles dates 14C obtenues sur plusieurs gisements pyrénéens

Factors to Improve the Management of Hepatitis C in Drug Users: An Observational Study in an Addiction Centre

Barriers to management of HCV in injection drug users are related to patients, health providers, and facilities. In a primary care drug user's addiction centre we studied access to HCV standard of care before and after using an onsite total care concept provided by a multidisciplinary team and noninvasive liver fibrosis evaluation. A total of 586 patients were seen between 2002 and 2004. The majority, 417 patients, were HCV positive and of these patients 337 were tested positive for HCV RNA. In 2002, patients were sent to the hospital. with the Starting of 2003, patients were offered standard of care HCV management in the center by a team of general practitioners, a consultant hepatologist, psychiatrists, nurses, and a health counsellor. Liver fibrosis was assessed by a non invasive method. In 2002, 6 patients had liver fibrosis assessment at hospital facilities, 4 patients were assessed with liver biopsy and 2 patients with Fibrotest-Actitest. 2 patients were treated for HCV at hospital. In 2003 and 2004, 224 patients were assessed with Fibrotest-Actitest on site. Of these, 85 were treated for HCV. SVR was achieved in 43%. We conclude that the combination of an onsite multidisciplinary team with the use of a noninvasive assessment method led to improved management of HCV infection in drug users' primary care facility