139 research outputs found

    Caractérisation des émergences du piémont de jbel Ayachi : contrôle structural et impact du changement climatique

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    Le massif calcaire de jbel Ayachi (Haute Atlas de Midelt), montre une structure complexe liée aux calcaires karstiques du Lias. Les nombreuses sources du relief indiquent l’existence d’importantes réserves d'eau. Dans le but de caractériser cet aquifère et de préciser les relations hydrodynamiques entre les zones de recharges et les sources de l’aquifères, une méthodologie a été utilisée. Elle comporte la synthèse des données géologiques, l’utilisation des techniques d’analyse structurale couplées aux études des débits et des chroniques de pluies. Les résultats de cette étude ont permis d’établir une comparaison des conditions d’émergence des deux sources (Ain Tatiouine, Ain Anzar Oufounès) et de l’évolution de leurs paramètres hydrodynamiques. Et une bonne corrélation entre les zones de recharges et les zones d’émergences. Elles permettront, à terme d’établir l’influence des changements climatiques sur les comportements hydrodynamiques de ces émergences.Mots-clés : sources, jbel Ayachi, Haute Atlas, lias, calcaire, karstique, débit, pluie, hydrodynamique, recharge, fissuration, fluctuations, émergence.Characterization of emergences piedmont of Jbel Ayachi. Structural control, and impact of climate changeThe calcareous solid mass of jbel Ayachi (High atlas of Midelt), shows a structure complex related to karstic limestones of Lias. The many sources of the relief indicate the existence of important water reserves. In order to characterize the aquifer and to clarify the relationship between hydrodynamic areas and springs of recharge of the aquifers, a methodology was used. It involves the synthesis of geological data, the use of structural analysis techniques coupled with studies of flow and chronic rain. The results of this study were used to compare the conditions of emergence of the two springs (Ain Tatiouine, Ain Anzar Oufounès) and changes in their hydrodynamic parameters. And good correlations between areas of recharge areas and emergences. They will eventually establish the influence of climate change on the hydrodynamic behavior of these emergences.Keywords : spring, Jbel Ayachi, High Atlas, lias, limestone, karst, flow, rain, hydrodynamics, recharge, cracking, fluctuations, emergence

    L-Ilf3 and L-NF90 Traffic to the Nucleolus Granular Component: Alternatively-Spliced Exon 3 Encodes a Nucleolar Localization Motif

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    Ilf3 and NF90, two proteins containing double-stranded RNA-binding domains, are generated by alternative splicing and involved in several functions. Their heterogeneity results from posttranscriptional and posttranslational modifications. Alternative splicing of exon 3, coding for a 13 aa N-terminal motif, generates for each protein a long and short isoforms. Subcellular fractionation and localization of recombinant proteins showed that this motif acts as a nucleolar localization signal. Deletion and substitution mutants identified four arginines, essential for nucleolar targeting, and three histidines to stabilize the proteins within the nucleolus. The short isoforms are never found in the nucleoli, whereas the long isoforms are present in the nucleoplasm and the nucleoli. For Ilf3, only the posttranslationally-unmodified long isoform is nucleolar, suggesting that this nucleolar targeting is abrogated by posttranslational modifications. Confocal microscopy and FRAP experiments have shown that the long Ilf3 isoform localizes to the granular component of the nucleolus, and that L-Ilf3 and L-NF90 exchange rapidly between nucleoli. The presence of this 13 aminoacid motif, combined with posttranslational modifications, is responsible for the differences in Ilf3 and NF90 isoforms subcellular localizations. The protein polymorphism of Ilf3/NF90 and the various subcellular localizations of their isoforms may partially explain the various functions previously reported for these proteins

    Pharmacogenetic profiling and cetuximab outcome in patients with advanced colorectal cancer

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    <p>Abstract</p> <p>Background</p> <p>We analyzed the influence of 8 germinal polymorphisms of candidate genes potentially related to EGFR signalling (<it>EGFR</it>, <it>EGF</it>, <it>CCND1</it>) or antibody-directed cell cytotoxicity (<it>FCGR2A </it>and <it>FCGR3A</it>) on outcome of colorectal cancer (CRC) patients receiving cetuximab-based therapy.</p> <p>Methods</p> <p>Fifty-eight advanced CRC patients treated with cetuximab-irinotecan salvage therapy between 2001 and 2007 were analyzed (mean age 60; 50 PS 0-1). The following polymorphisms were analyzed on blood DNA: <it>EGFR </it>(CA repeats in intron 1, -216 G > T, -191C > A, R497K), <it>EGF </it>(A61G), <it>CCND1 </it>(A870G), <it>FCGR2A </it>(R131H), <it>FCGR3A </it>(F158V). Statistical analyses were conducted on the total population and on patients with wt KRas tumors. All SNPs were considered as ternary variables (wt/wt <it>vs </it>wt/mut <it>vs </it>mut/mut), with the exception of -191C > A <it>EGFR </it>polymorphism (AA patient merged with CA patients).</p> <p>Results</p> <p>Analysis of skin toxicity as a function of EGFR intron 1 polymorphism showed a tendency for higher toxicity in patients with a low number of CA-repeats (p = 0.058). <it>CCND1 </it>A870G polymorphism was significantly related to clinical response, both in the entire population and in KRas wt patients, with the G allele being associated with a lack of response. In wt KRas patients, time to progression (TTP) was significantly related to <it>EGFR </it>-191C > A polymorphism with a longer TTP in CC patients as compared to others, and to <it>CCND1 </it>A870G polymorphism with the G allele being associated with a shorter TTP; a multivariate analysis including these two polymorphisms only retained <it>CCND1 </it>polymorphism. Overall survival was significantly related to <it>CCND1 </it>polymorphism with a shorter survival in patients bearing the G allele, and to <it>FCGR3A </it>F158V polymorphism with a shorter survival in VV patients (in the entire population and in KRas wt patients). <it>FCGR3A </it>F158V and <it>CCND1 </it>A870G polymorphisms were significant independent predictors of overall survival.</p> <p>Conclusions</p> <p>Present original data obtained in wt KRas patients corresponding to the current cetuximab-treated population clearly suggest that <it>CCND1 </it>A870G polymorphism may be used as an additional marker for predicting cetuximab efficacy, TTP and overall survival. In addition, <it>FCGR3A </it>F158V polymorphism was a significant independent predictor of overall survival.</p

    A comprehensive structural, biochemical and biological profiling of the human NUDIX hydrolase family

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    The NUDIX enzymes are involved in cellular metabolism and homeostasis, as well as mRNA processing. Although highly conserved throughout all organisms, their biological roles and biochemical redundancies remain largely unclear. To address this, we globally resolve their individual properties and inter-relationships. We purify 18 of the human NUDIX proteins and screen 52 substrates, providing a substrate redundancy map. Using crystal structures, we generate sequence alignment analyses revealing four major structural classes. To a certain extent, their substrate preference redundancies correlate with structural classes, thus linking structure and activity relationships. To elucidate interdependence among the NUDIX hydrolases, we pairwise deplete them generating an epistatic interaction map, evaluate cell cycle perturbations upon knockdown in normal and cancer cells, and analyse their protein and mRNA expression in normal and cancer tissues. Using a novel FUSION algorithm, we integrate all data creating a comprehensive NUDIX enzyme profile map, which will prove fundamental to understanding their biological functionality

    31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

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    Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

    A newAinformative new Informative genericGeneric base of Base association of Association rules Rules

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    Abstract. The problem of the relevance and the usefulness of extracted association rules is becoming of primary importance, since an overwhelming number of association rules may be derived from even reasonably sized real-life databases. In this paper, we introduce a novel generic base of association rules, based on the Galois connection semantics. The novel generic base is sound and informative. We also present a sound axiomatic system, allowing to derive all association rules that can be drawn from an extraction context.
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