996 resultados para protective group


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Invasive fungal diseases (IFDs) have become major causes of morbidity and mortality among highly immunocompromised patients. Authoritative consensus criteria to diagnose IFD have been useful in establishing eligibility criteria for antifungal trials. There is an important need for generation of consensus definitions of outcomes of IFD that will form a standard for evaluating treatment success and failure in clinical trials. Therefore, an expert international panel consisting of the Mycoses Study Group and the European Organization for Research and Treatment of Cancer was convened to propose guidelines for assessing treatment responses in clinical trials of IFDs and for defining study outcomes. Major fungal diseases that are discussed include invasive disease due to Candida species, Aspergillus species and other molds, Cryptococcus neoformans, Histoplasma capsulatum, and Coccidioides immitis. We also discuss potential pitfalls in assessing outcome, such as conflicting clinical, radiological, and/or mycological data and gaps in knowledge.

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Background: Inflammatory bowel disease (IBD) is characterized by chronic intestinal inflammation due to dysregulation of the mucosal immune system. The cytokines IL-1β and IL-18 appear early in intestinal inflammation and their pro-forms are processed via the caspase-1-activating multiprotein complex, the Nlrp3 inflammasome. Previously, we reported that the uptake of dextran sodium sulfate (DSS) by macrophages activates the Nlrp3 inflammasome and that Nlrp3(-/-) mice are protected in the acute DSS colitis model. Of note, other groups have reported opposing effects in regards to DSS susceptibility in Nlrp3(-/-) mice. Recently, mice lacking inflammasomes were found to develop a distinct intestinal microflora. Methods: To reconcile the contradicting observations, we investigated the role of Nlrp3 deficiency in two different IBD models: acute DSS colitis and TNBS (2,4,6-trinitrobenzene sulfonic acid)-induced colitis. In addition, we investigated the impact of the intestinal flora on disease severity by performing cohousing experiments of wild-type and Nlrp3(-/-) mice, as well as by antibiotic treatment. Results: Nlrp3(-/-) mice treated with either DSS or TNBS exhibited attenuated colitis and lower mortality. This protective effect correlated with an increased frequency of CD103+ lamina propria dendritic cells expressing a tolerogenic phenotype in Nlrp3(-/-) mice in steady state conditions. Interestingly, after cohousing, Nlrp3(-/-) mice were as susceptible as wild-type mice, indicating that transmission of endogenous bacterial flora between the two mouse strains might increase susceptibility of Nlrp3(-/-) mice towards DSS-induced colitis. Accordingly, treatment with antibiotics almost completely prevented colitis in the DSS model. Conclusions: The composition of the intestinal microflora significantly influences disease severity in IBD models comparing wild-type and Nlrp3(-/-) mice. This observation may - at least in part - explain contradictory results concerning the role of the inflammasome in different labs. Further studies are required to define the role of the Nlrp3 inflammasome in noninflamed mucosa under steady state conditions and in IBD.

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BACKGROUND: The storage of blood induces the formation of erythrocytes-derived microparticles. Their pathogenic role in blood transfusion is not known so far, especially the risk to trigger alloantibody production in the recipient. This work aims to study the expression of clinically significant blood group antigens on the surface of red blood cells microparticles. MATERIAL AND METHODS: Red blood cells contained in erythrocyte concentrates were stained with specific antibodies directed against blood group antigens and routinely used in immunohematology practice. After inducing erythrocytes vesiculation with calcium ionophore, the presence of blood group antigens was analysed by flow cytometry. RESULTS: The expression of several blood group antigens from the RH, KEL, JK, FY, MNS, LE and LU systems was detected on erythrocyte microparticles. The presence of M (MNS1), N (MNS2) and s (MNS4) antigens could not be demonstrated by flow cytometry, despite that glycophorin A and B were identified on microparticles using anti-CD235a and anti-MNS3. DISCUSSION: We conclude that blood group antigens are localized on erythrocytes-derived microparticles and probably keep their immunogenicity because of their capacity to bind specific antibody. Selective segregation process during vesiculation or their ability to elicit an immune response in vivo has to be tested by further studies.

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Because of its severity, it is agreed that infectious endocarditis should be prevented whenever possible. Determining adequate prophylactic measures involves establishing (a) the patients at risk, (b) the procedures that might provoke bacteraemia, (c) the most effective prophylactic regimen, and (d) a balance between the risks of side effects from prophylaxis and of developing infectious endocarditis. Patients at risk and procedures inducing bacteraemia have been identified by clinical studies. On the other hand, the efficacy of prophylactic antibiotics has been based on animal studies. Randomised, placebo-controlled studies do not exist in humans because they would require large patient numbers and would raise ethical issues due to the severity of the disease. Case-control studies have indicated that infectious endocarditis prophylaxis is effective, but prevents only a limited number of cases. Animal experiments have revealed several key issues for human application. First, antibiotics do not prevent the early stages of valve colonisation, but rather kill the microorganisms after their attachment to the cardiac lesions. Second, the duration of antibiotic presence in the serum is critical. Under experimental conditions, the drugs must remain above their minimal inhibitory concentration for the organisms for > or = 10 h, to allow time for bacterial clearance from the valves. Third, antibiotic-induced killing is not the only mechanism allowing bacterial clearance. Other factors, such as platelet microbicidal proteins, may act in concert with the drugs to sterilise the lesions. Recommendations for prophylaxis have recently been revised in Europe and the USA. New information has improved the definition of groups at risk. Since most cases of infectious endocarditis are not preceded by medical procedures, primary prevention of infectious endocarditis should target infected foci responsible for spontaneous bacteraemia (e.g. poor dental hygiene). The purpose of this article is to update the existing recommendations in Switzerland, under the perspective of changing epidemiology, the availability of new drugs, and harmonisation with recommendations in other countries.

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Puerperium is a period of great changes in women's lives, in physiological, psychological and socio-cultural terms. Female sexuality is a broad topic that should be explored vis-à-vis the singularity of woman's experiences which themselves vary at different moments in time. This article is part of the project: Sexuality in the Puerperium, the objective of which was to understand what women's experience of their sexuality is in the postpartum period. Observation and semi-structured interview were used. The research approach was qualitative and narrative was used as the conceptual and methodological method. Six primiparas who gave birth in a public hospital in São Paulo took part in the study. Observation took place in the in-patients unit in the immediate post-partum period. The interviews were conducted in the women´s homes. The results of the study have enabled an understanding to be formed of the meanings and changes in sexuality during the postpartum period as well as of the experiences every woman faces in her new roles, relationships and difficulties.

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Background: The high polymorphism rate in the human ABO blood group gene seems to be related to susceptibility to different pathogens. It has been estimated that all genetic variation underlying the human ABO alleles appeared along the human lineage, after the divergence from the chimpanzee lineage. A paleogenetic analysis of the ABO blood group gene in Neandertals allows us to directly test for the presence of the ABO alleles in these extinct humans. Results: We have analysed two male Neandertals that were retrieved under controlled conditions at the El Sidron site in Asturias (Spain) and that appeared to be almost free of modern human DNA contamination. We find a human specific diagnostic deletion for blood group O (O01 haplotype) in both Neandertal individuals. Conclusion: These results suggest that the genetic change responsible for the O blood group in humans predates the human and Neandertal divergence. A potential selective event associated with the emergence of the O allele may have therefore occurred after humans separated from their common ancestor with chimpanzees and before the human-Neandertal population divergence.

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Because of their beneficial impact on forest ecosystems, European red wood ants (Formica rufa group) are protected by law in many European countries and are considered to be among the most reliable bioindicators of forest stability. However, their taxonomy has been much debated and, unfortunately, it is too often neglected. This happens mainly because the morphology-based method for species delimitation requires lots of time and experience. We therefore employed 9 microsatellite loci and mitochondrial DNA (COI gene) to verify the power of genetic markers for red wood ant species delimitation and to investigate the cryptic diversity of these ants within the Eastern Swiss Alps. We analyzed 83 nests belonging to all red wood ant species that occur in the Swiss National Park area. Genetic data indicated that these species represent different genetic pools. Moreover, results showed that Formica aquilonia YARROW, 1955 and F. paralugubris SEIFERT, 1996 often hybridize within the Park, confirming that these two species are genetically very close and could have diverged only recently. Nevertheless, microsatellites also revealed that one entire population, located in the Minger Valley and morphologically identified as F. lugubris ZETTERSTEDT, 1838, is genetically different to all other analyzed F. lugubris populations found within the same area and to other red wood ant species. These findings, confirmed by mitochondrial DNA analyses, suggest the existence of a new cryptic species within the Eastern Swiss Alps. This putative cryptic species has been provisionally named F. lugubris-A2. These results have a great importance for future conservation plans, monitoring and evolutionary studies on these protected ants.

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Les muqueuses sont les membranes tapissant les cavités du corps, tel que le tube digestif, et sont en contact direct avec l'environnement extérieur. Ces surfaces subissent de nombreuses agressions pouvant être provoquées par des agents pathogènes (bactéries, toxines ou virus). Cela étant, les muqueuses sont munies de divers mécanismes de protection dont notamment deux protéines-clés permettant de neutraliser les agents pathogènes : les anticorps ou immunoglobulines sécrétoires A (SIgA) et M (SIgM). Ces anticorps sont, d'une part, fabriqués au niveau de la muqueuse sous forme d'IgA et IgM. Lorsqu'ils sont sécrétés dans l'intestin, ils se lient à une protéine appelée pièce sécrétoire et deviennent ainsi SIgA et SïgM. La présence de la pièce sécrétoire est essentielle pour que les anticorps puissent fonctionner au niveau de la muqueuse. D'autre part, ces anticorps sont également fabriqués dans d'autres parties du corps en général et se retrouvent dans le sang sous forme d'IgA et IgM Chez l'homme, des thérapies basées sur l'injection d'anticorps donnent de bons résultats depuis de nombreuses années notamment dans le traitement des infections. Bien qu'un certain nombre d'études ont montré le rôle protecteur des anticorps de type IgA et IgM, ceux-ci ne sont que rarement utilisés dans les thérapies actuelles. La principale raison de cette faible utilisation réside dans la production ou la purification des IgA/IgM ou SIgA/SIgM (la forme active au niveau des muqueuses) qui est difficile à réaliser à large échelle. Ainsi, le but de la thèse était (1) d'étudier la possibilité d'employer des IgA et des IgM provenant du sang humain pour générer des SIgA et SIgM et (2) de voir si ces anticorps reconstitués pouvaient neutraliser certains agents pathogènes au niveau des muqueuses. Tout d'abord, une analyse biochimique des IgA et des IgM issues du sang a été effectuée. Nous avons observé que ces anticorps avaient des caractéristiques similaires aux anticorps naturellement présents au niveau des muqueuses. De plus, nous avons confirmé que ces anticorps pouvaient être associés à une pièce sécrétoire produite en laboratoire pour ainsi donner des SIgA et SIgM reconstituées. Ensuite, la fonctionnalité des anticorps reconstitués a été testée grâce à un modèle de couche unique de cellules intestinales différenciées (monocouches) en laboratoire imitant la paroi de l'intestin. Ces monocouches ont été infectées par une bactérie pathogène, Shigella flexneri, responsable de la shigellose, une maladie qui provoque des diarrhées sanglantes chez l'homme. L'infection des monocouches par les bactéries seules ou combinées aux SIgA et SIgM reconstituées a été analysée. Nous avons observé que les dommages des cellules étaient moins importants lorsque les SIgA étaient présentes. Il apparaît que les SIgA neutralisent les bactéries en se fixant dessus, ce qui provoque leur agrégation, et diminuent l'inflammation des cellules. La protection s'est montrée encore plus efficace avec les SIgM. De plus, nous avons vu que les SIgA et SIgM pouvaient diminuer la sécrétion de facteurs nocifs produits par les bactéries. Utilisant le même modèle des monocouches, la fonctionnalité des IgA issues du sang humain a aussi été testée contre une toxine sécrétée par une bactérie appelée Clostridium diffìcile. Cette bactérie peut être présente naturellement dans l'intestin de personnes saines, cependant elle peut devenir pathogène dans certaines conditions et être à l'origine de diarrhées et d'inflammations de l'intestin via la sécrétion de toxines. Des préparations d'anticorps contenant une certaine proportion de SIgA reconstituées ont amené à une diminution des dommages et de l'inflammation des monocouches causés par la toxine. L'ensemble de ces résultats prometteurs, montrant que des SIgA et SIgM reconstituées peuvent protéger la paroi de l'intestin des infections bactériennes, nous conduisent à approfondir la recherche sur ces anticorps dans des modèles animaux. L'aboutissement de ce type de recherche permettrait de tester, par la suite, l'efficacité sur l'homme de traitements des infections des muqueuses par injection d'anticorps de type SIgA et SIgM reconstituées. Les muqueuses, telle que la muqueuse gastrointestinale, sont des surfaces constamment exposées à l'environnement et leur protection est garantie par une combinaison de barrières mécaniques, physicochimiques et immunologiques. Parmi les divers mécanismes de protection immunologiques, la réponse humorale spécifique joue un rôle prépondérant et est assurée par les immunoglobulines sécrétoires de type A (SIgA) et M (SIgM). Les thérapies basées sur l'administration d'IgG apportent d'importants bénéfices dans le domaine de la santé. Bien que des études sur les animaux aient montré que l'administration par voie muqueuse d'IgA polymérique (plgA) ou SIgA pouvaient protéger des infections, des IgA/SIgA n'ont été utilisées qu'occasionnellement dans les thérapies. De plus, des études précliniques et cliniques ont démontré que l'administration par voie systémique de préparations enrichies en IgM pouvait aussi protéger des infections. Cependant, l'administration par voie muqueuse d'IgM/SIgM purifiées n'a pas été examinée jusqu'à présent. La principale raison est que la purification ou là production des IgA/SIgA et IgM/SIgM est difficile à réaliser à large échelle. Le but de ce travail de thèse était d'examiner la possibilité d'associer des IgA et IgM polyclonals purifiées à partir du plasma humain avec une pièce sécrétoire recombinante humaine afin de générer des SIgA et SIgM reconstituées fonctionnelles. Tout d'abord, une analyse biochimique des IgA et IgM issues du plasma humain a été effectuée par buvardage de western et Chromatographie. Ces molécules avaient des caractéristiques biochimiques similaires à celles des immunoglobulines issues de la muqueuse. L'association entre plgA ou IgM issues du plasma humain et la pièce sécrétoire recombinante humaine a été confirmée, ainsi que la stoechiométrie 1:1 de l'association. Comme dans les conditions physiologiques, cette association permettait de retarder la dégradation des SIgA et SIgM reconstituées exposées à des protéases intestinales. Ensuite, la fonctionnalité et le mode d'action des IgA et IgM issues du plasma humain, ainsi que des SIgA et SIgM reconstituées, ont été explorés grâce à un modèle in vitro de monocouches de cellules intestinales épithéliales polarisées de type Caco-2, qui imite l'épithélium intestinal. Les monocouches ont été infectées par un pathogène entérique, Shigella flexneri, seul ou combiné aux immunoglobulines issues du plasma humain ou aux immunoglobulines sécrétoires reconstituées. Bien que les dommages des monocouches aient été retardés par les plgA et SIgA reconstituées, les IgM et SIgM reconstituées se sont montrées supérieures dans le maintien de l'intégrité des cellules. Une agrégation bactérienne et une diminution de l'inflammation des monocouches ont été observées avec les plgA et SIgA reconstituées. Ces effets étaient augmentés avec les IgM et SIgM reconstituées. De plus, il s'est révélé que les deux types d'immunoglobulines de type sécrétoire reconstituées agissaient directement sur la virulence des bactéries en réduisant leur sécrétion de facteurs de virulence. La fonctionnalité des IgA issues du plasma humain a aussi été testée contre la toxine A de Clostridium difficile grâce au même modèle de monocouches de cellules épithéliales. Nous avons démontré que des préparations enrichies en IgA provenant du plasma humain pouvaient diminuer les dommages et l'inflammation des monocouches induits par la toxine. L'ensemble de ces résultats démontrent que des IgA et IgM de type sécrétoire peuvent être générées à partir d'IgA et IgM issues du plasma humain en les associant à la pièce sécrétoire et que ces molécules protègent l'épithélium intestinal contre des bactéries pathogènes. Ces molécules pourraient dès lors être testées dans des modèles in vivo. Le but final serait de les utiliser chez l'homme à des fins d'immunisation passive dans le traitement de pathologies associées à la muqueuse telles que les infections. - Mucosal surfaces, such as gastrointestinal mucosa, are constantly exposed to the external environment and their protection is ensured by a combination of mechanical, physicochemical and immunological barriers. Among the various immunological defense mechanisms, specific humoral mucosal response plays a crucial role and is mediated by secretory immunoglobulins A (SIgA) and M (SIgM). Immunoglobulin therapy based on the administration of IgG molecules leads important health benefits. Even though animal studies have shown that mucosal application of polymeric IgA (plgA) or SIgA provided protection against infections, IgA/SIgA have been only used occasionally for therapeutic application. Moreover, preclinical and clinical studies have demonstrated that systemic administration of IgM-enriched preparations could also afford protection against infections. Nevertheless, mucosal application of purified IgM/SIgM has not been examined. The main reason is that the purification or production of IgA/SIgA and IgM/SIgM at large scale is difficult to achieve. The aim of this PhD project was to examine the possibility to associate polyclonal human plasma-derived IgA and IgM with recombinant human secretory component (SC) to generate functional secretoiy-like IgA and IgM. First, biochemical analysis of human plasma IgA and IgM was performed by western blotting and chromatography. These molecules exhibited the same biochemical features as mucosa-derived antibodies (Abs). The association between human plasma plgA or IgM and recombinant human SC was confirmed, as well as the 1:1 stoichiometry of association. Similarly to physiological conditions, this association delayed the degradation of secretory-like IgA or IgM by intestinal proteases. Secondly, the function activity and the mode of action of human plasma IgA and IgM, as well as secretory-like IgA and IgM were explored using an in vitro model of polarized intestinal epithelial Caco-2 cell monolayers mimicking intestinal epithelium. Cell monolayers were infected with an enteropathogen, Shigella flexneri, alone or in combination to plasma Abs or secretory-like Abs. Even though plasma plgA and secretoiy-like IgA resulted in a delay of bacteria-induced damages of cell monolayers, plasma IgM and secretory-like IgM were shown to be superior in maintenance of cell integrity. Polymeric IgA and secretory-like IgA induced bacterial aggregation and decreased cell monolayer inflammation, effects further amplified with IgM and secretory-like IgM. In addition, both secretory-like Abs directly impacted on bacterial virulence leading to a reduction in secretion of virulence factors by bacteria. The functionality of human plasma IgA was also tested against Clostridium difficile toxin A using Caco-2 cell monolayers. Human plasma IgA- enriched preparations led to a diminution of cell monolayer damages and a decrease of cellular inflammation induced by the toxin. The sum of these results demonstrates that secretory-like IgA and IgM can be generated from purified human plasma IgA and IgM associated to SC and that these molecules are functional to protect intestinal epithelium from bacterial infections. These molecules could be now tested using in vivo models. The final goal would be to use them by passive immunization in the treatment of mucosa-associated pathologies like infections in humans.

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Robertsonian (Rb) fusions received large theoretical support for their role in speciation, but empirical evidence is often lacking. Here, we address the role of Rb rearrangements on the genetic differentiation of the karyotypically diversified group of shrews, Sorex araneus. We compared genetic structure between 'rearranged' and 'common' chromosomes in pairwise comparisons of five karyotypic taxa of the group. Considering all possible comparisons, we found a significantly greater differentiation at rearranged chromosomes, supporting the role of chromosomal rearrangements in the general genetic diversification of this group. Intertaxa structure and distance were larger across rearranged chromosomes for most of the comparisons, although these differences were not significant. This last result could be explained by the large variance observed among microsatellite-based estimates. The differences observed among the pairs of taxa analysed support the role of both the hybrid karyotypic complexity and the level of evolutionary divergence.

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When applying a Collaborative Learning Flow Pattern (CLFP) to structure sequences of activities in real contexts, one of the tasks is to organize groups of students according to the constraints imposed by the pattern. Sometimes,unexpected events occurring at runtime force this pre-defined distribution to be changed. In such situations, an adjustment of the group structures to be adapted to the new context is needed. If the collaborative pattern is complex, this group redefinitionmight be difficult and time consuming to be carried out in real time. In this context, technology can help on notifying the teacher which incompatibilitiesbetween the actual context and the constraints imposed by the pattern. This chapter presents a flexible solution for supporting teachers in the group organization profiting from the intrinsic constraints defined by a CLFPs codified in IMS Learning Design. A prototype of a web-based tool for the TAPPS and Jigsaw CLFPs and the preliminary results of a controlled user study are alsopresented as a first step towards flexible technological systems to support grouping tasks in this context.

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This study analyses the characteristics of members leaving a Spanishunion federation – Catalonia branch of Workers’ Commissions(CCOO-Catalonia), together with their reasons for leaving using avariety of data sources. Our findings indicate that higher union attritionamong members in instable employment (i.e. casual employment andlow seniority). In general, union leavers confirm that their job situationis an important reason for leaving the union. We therefore concludethat efforts made by the union to retain members in vulnerable labormarket positions are important in reducing high rates of union attritionin Spain.

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In hybrid zones, endogenous counter-selection of hybrids is usually first expressed as reduced fertility or viability in hybrids of the heterogametic sex, a mechanism known as Haldane's rule. This phenomenon often leads to a differential of gene flow between sex-linked markers. Here, we address the possibility of a differential gene flow for Y chromosome, mtDNA and autosomal markers across the hybrid zone between the genetically and chromosomally well-differentiated species Sorex antinorii and Sorex araneus race Vaud. Intermarker comparison clearly revealed coincidental centre and very abrupt clines for all three types of markers. The overall level of genetic differentiation between the two species must be strong enough to hinder asymmetric introgression. Cyto-nuclear mismatches were also observed in the centre of hybrid zone. The significantly lower number of mismatches observed in males than in females possibly results from Y chromosome-mtDNA interactions. Results are compared with those previously reported in another hybrid zone between S. antinori and S. araneus race Cordon.