1,721,010 research outputs found
Caractérisation moléculaire des souches de leishmania infantum et évaluation de nouveaux médicaments pour soigner la leishmaniose viscérale
No full textLa leishmaniose viscérale (LV) est la forme la plus sévère de la leishmaniose humaine. Elle est transmise par la piqûre d'un phlébme. La leishmaniose viscérale est mortelle en l'absence de traitement. Les options thérapeutiques courantes contre la leishmaniose viscérale sont limitées. En région méditerranéenne, la LV est due à Leishmania infantum, zoonose dont le chien est le principal réservoir. A côté de quelques cas d'infection systémique, un nombre important d'humains porteurs asymptomatiques a été mis en evidence. En première partie, nous avons étudié l'intérêt du MultiLocus Microsatellite Genotyping (MLMT) pour l'identification des souches de Leishmania du sud de la France. Par MLMT nous avons étudié la variabilité génétique de différentes souches et recherché une association avec les différentes formes cliniques, la résistance aux médicaments et les phénomènes de rechutes. Nous avons observé une hétérogénéité génétique entre les différentes souches de L. infantum MON-1. Si l'association de certains génotypes avec les différentes expressions cliniques de la leishmaniose n'a pu être démontrée, nous avons par contre observé une répartition préférentielle géographique de certains génotypes. En deuxième partie, nous avons mis au point un protocole expérimental destiné au criblage de nouveaux agents anti-Leishmania infantum ayant pour cible la machinerie cellulaire mise en route par la cellule hôte pour l'élimination du parasite intracellulaire. Nos résultats ont montré que les altérations du système de trafic intracellulaire de la cellule-hôte induites par certains composés étaient corrélées à la mort du parasite et à son élimination.Visceral leishmaniasis (VL) is the most severe form of Human Leishmaniases, which occurs when protozoan parasites Leishmania donovani or L. infantum, given by phlebotomine sandfly bites. The disease is fatal when untreated. Current treatment options against VL are very limited with few drug molecules, often expensive, not always safe and able to induce resistance phenomenon.In this report, we have characterized on one hand, different genetic variants of Leishmania infantum strains isolated in different geographical areas from southern France and on the other hand have identified new potential anti-Leishmania infantum compounds and characterized their molecular mechanism of action.In the first part, we studied the interest of Multilocus Microsatellite Genotyping (MLMT) for the identification of Leishmania strains from southern France. By genotyping technique MLMT, we studied the genetic variability of different strains and sought an association with different clinical forms of leishmaniasis, resistance to drugs and relapse. We observed genetic heterogeneity among different strains of L. infantum-MON-1. we observed a preferential geographic distribution of certain genotypes.In the second part, we have developed an experimental protocol for the screening of new anti-Leishmania infantum compounds that target the host cell machinery responsible for the intracellular parasite killing, we studied the different steps of endocytic pathways potentially targeted by these compounds. Our results showed that with some compounds, modifications of the intracellular trafficking of the host cell were correlated with parasite death and its elimination
Les leishmanioses: Biodiversité et Pathogénicité: Etude comparative des caractères génétiques du complexe Leishmania (Leishmania) donovani, agent de la leishmaniose viscérale
No full textNational audienceLes espèces parasitaires du complexe Leishmania (Leishmania) donovani sont responsables des leishmanioses les plus graves, les leishmanioses viscérales, mais peuvent aussi provoquer des formes cutanées bénignes. Plusieurs facteurs peuvent influencer cette variabilité pathogénique (l'hôte, l'environnement et/ou le parasite). Ce livre, focalisé sur le parasite, étudie les caractères génétiques et les met en regard avec la variabilité pathogénique. La question posée est donc: Existe-t- il des différences génétiques entre des parasites isolés de lésions cutanées et de lésions viscérales Ce livre explore la diversité génétique globale à l'aide de différents marqueurs neutres (isoenzymes, microsatellites) ainsi que le polymorphisme de séquence et l'expression de gènes intervenant dans différents processus cellulaires et aux différents stades de développement du parasite. L'analyse phylogénétique de tous les marqueurs génétiques utilisés dans ce travail, permet de clarifier le statut des espèces du complexe donovani et de poser les bases génétiques indispensables à toute étude de la diversité pathogénique des agents infectieux
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Species-specific PCR assay for L-infantum L-donovani discrimination
No full textLeishmania infantum and Leishmania donovani both pertain to the L. (L.) donovani complex. The status of certain strains is questioned in the literature and there are no reliable discriminative markers to identify them. Molecular tools are needed to (i) identify diagnostic markers and (ii) to allow a better understanding of phylogenetic relationships. We have developed a PCR based on cysteine protease B (cpb). This PCR discriminates between L. infantum and L. donovani with 50-100 pg of DNA. These two species are differentiated by their fragment length. Indeed, L. donovani strains were characterized by a 741-bp product and L. infantum strains by a 702-bp product, except for one strain, which revealed a heterozygous profile with the two products. This PCR does not generate amplification for other Leishmania or kinetoplastids and Could contribute to clarify the phylogenetic status of several taxa that are also being debated, such as L. archibaldi
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