989 resultados para Strategic responses


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Annual Report, Strategic Plan and Performance Plan

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Phosphate (Pi) availability is a major factor limiting growth, development, and productivity of plants. In both ecological and agricultural contexts, plants often grow in soils with low soluble phosphate content. Plants respond to this situation by a series of developmental and metabolic adaptations that are aimed at increasing the acquisition of this vital nutrient from the soil, as well as to sustain plant growth and survival. The development of a comprehensive understanding of how plants sense phosphate deficiency and coordinate the responses via signaling pathways has become of major interest, and a number of signaling players and networks have begun to surface for the regulation of the phosphate-deficiency response. In practice, application of such knowledge to improve plant Pi nutrition is hindered by complex cross-talks, which are emerging in the face of new data, such as the coordination of the phosphate-deficiency signaling networks with those involved with hormones, photo-assimilates (sugar), as well as with the homeostasis of other ions, such as iron. In this review, we focus on these cross-talks and on recent progress in discovering new signaling players involved in the Pi-starvation responses, such as proteins having SPX domains.

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RÉSUMÉ La sclérose en plaques (SEP) est une maladie démyélinisante du système nerveux central (SNC) qui touche le plus souvent de jeunes femmes. Bien qu'elle ait été décrite pour la première fois il y a plus de 200 ans, son étiologie n'est pas encore complètement comprise. Contrairement à d'autres maladies purement génétiques, l'épidémiologie de la SEP ne peut être que partiellement expliquée par des facteurs génétiques. Ceci suggère que des facteurs environnementaux pourraient être impliqués dans la pathogenèse de la SEP. Parmi ceux-ci, le virus d'Epstein-Barr (EBV) est un excellent candidat, comme cela a été démontré par de larges études séroépidémiologiques ainsi que pax l'évaluation de la réponse cellulaire dans le sang. Bien que le SNC soit en fait la cible des réponses immunitaires anormales dans la SEP, peu d'études ont été accomplies sur les réponses immunitaires spécifiques à EBV dans ce compartiment. Ceci est particulièrement vrai chez des patients vivants chez lesquels des biopsies sont rarement effectuées, ainsi que pour les réponses cellulaires car très peu de cellules immunitaires peuvent être obtenues du SNC. Nous avons donc développé des conditions de cultures et un readout nous permettant d'étudier le nombre réduit de cellules disponibles dans le liquide céphalo-rachidien (LCR), qui représente le seul matériel pouvant être obtenu du SNC de patients SEP vivants. Nous avons trouvé que les réponses cellulaires et humorales spécifiques à EBV étaient augmentées dans le LCR des patients SEP comparé à du sang pairé, ainsi que par rapport à des patients avec d'autres maladies neurologiques inflammatoires et noninflammatoires. Afin de déterminer si les réponses immunitaires augmentées contre EBV étaient spécifiques à ce virus ou si elles reflétaient simplement une hyperactivation immunitaire aspécifique, nous avons comparé les réponses spécifiques à EBV avec celles spécifiques au cytomegalovirus (CNN). En effet, comme EBV, CNN est un herpesvirus neurotropique qui peut établir des infections latentes, mais ce dernier n'est pas considéré comme étant associé à la SEP. De façon intéressante, les réponses immunitaires spécifiques à CNN trouvées dans le LCR étaient plus basses que dans le sang, et ceci dans toutes les catégories de patients. Ces données suggèrent qu'une réactivation d'EBV pourrait avoir lieu dans le SNC des patients SEP à un stade précoce de la maladie et renforcent fortement l'hypothèse qu'EBV pourrait avoir un rôle déclencheur dans cette maladie. Ainsi, il pourrait être intéressant d'explorer si un traitement ou un vaccin efficace contre EBV peut prévenir le développement de la SEP. On ne connaît toujours pas la raison pour laquelle les réponses immunitaires spécifiques à EBV sont augmentées chez les patients SEP. Une hypothèse est que la réponse immunitaire est qualitativement différente chez les patients SEP par rapports aux contrôles. Pour examiner ceci, nous avons évalué le profile cytokinique de lymphocytes T CD4+ et CD8+ stimulés par EBV, mais nous n'avons pas pu mettre en évidence de différence remarquable entre patients SEP et sujets sains. Cette question reste donc ouverte et d'autres études sont justifiées. Il n'existe pas de marqueur fiable de la SEP. Ici, nous avons trouvé que la cytokine IL-26, récemment décrite, était augmentée dans les lymphocytes T CD8+ des patients avec une SEP secondairement progressive comparé à des patients SEP en poussée, des patients avec une SEP primairement progressive, des patients avec d'autres maladies neurologiques inflammatoires, ou des sujets sains. De plus, nous avons identifié des types de cellules dérivées du cerveau (astrocytes, oligodendrocytes et neurones) qui exprimaient le récepteur de l'IL-26. Ceci ouvre la voie à d'autres études afin de mieux comprendre la fonction de l'II.-26 et son interaction avec la. SEP. SUMMARY : Multiple sclerosis (MS) is a demyelinating disease affecting the central nervous system (CNS), mostly in young female adults. Although it was first described 200 years ago, its etiology is still not completely understood. Contrary to other purely genetic diseases, genetics can explain only part of MS epidemiology. Therefore, environmental factors that might be involved in MS pathogenesis were searched for. Among them, Epstein-Barr virus (EBV) is a strong potential candidate, such as shown by large seroepidemiological studies and cellular immune response assessments in the blood. Although the CNS is the actual target of abnormal immune responses in MS, few studies have been performed on EBV-specific immune responses in this compartment. This is particularly true for live patients, from which biopsy material is almost never available, and for cellular immune responses, since very few immune cells are available from the CNS. We therefore developed culture conditions and a readout that were compatible with the study of the reduced number of cells found in the cerebrospinal fluid (CSF), the only readily available material from the CNS of live ' MS patients. We found that EBV-specific cellular and humoral immune responses were increased in the CSF of MS patients as compared with paired blood, as well as compared with the CSF of patients with other inflammatory and non-inflammatory neurological diseases. To determine whether the enhanced immune responses against EBV were specific of this virus or simply reflected an aspecific immune hyperactivation, we compared the EBV- with the cytomegalovirus (CMV)-specific immune responses. Indeed, like EBV, CMV is a neurotrophic herpesvirus that can establish latent infections, but the latter is not considered to be associated with MS. Interestingly, CSF CMV-specific immune responses were lower than blood ones and this, in all patient categories. These findings suggest that EBV reactivation may be taking place in the CNS of patients at the early stages of MS and strengthen the hypothesis that EBV may have a triggering role in this disease. Therefore, it might be interesting to explore whether an efficient anti-EBV drug or vaccine is able to prevent MS development. The reason why EBV-specific immune responses are increased in MS patients is still missing. One hypothesis might be that the immune response against EBV is qualitatively different in MS patients as compared with controls. To examine this, we assessed the cytokine mRNA profile of EBV-stimulated CD4+ and CD8+ T cells, but could not find any remarkable difference between MS patients and healthy controls. Therefore, this question remains open and fiirther studies are warranted. Reliable disease markers are lacking for MS. Here, we found that the recently described cytokine IL-26 was increased in CD8+ T cells of patients with secondary progressive MS as compared with relapsing MS, primary progressive MS, other inflammatory neurological diseases and healthy controls. Moreover, we identified brain cell types (astrocytes, oligodendrocytes and neurons) that expressed the IL-26 receptor, paring the way for further studies to understand IL-26 function and its interaction with MS.

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In this paper we view bargaining and cooperation as an interaction superimposed on a strategic form game. A multistage bargaining procedure for N players, the proposer commitment procedure, is presented. It is inspired by Nash s two-player variable-threat model; a key feature is the commitment to threats. We establish links to classical cooperative game theory solutions, such as the Shapley value in the transferable utility case. However, we show that even in standard pure exchange economies the traditional coalitional function may not be adequate when utilities are not transferable.

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In experiments with two-person sequential games we analyzewhether responses to favorable and unfavorable actions dependon the elicitation procedure. In our hot treatment thesecond player responds to the first player s observed actionwhile in our cold treatment we follow the strategy method and have the second player decide on a contingent action foreach and every possible first player move, without firstobserving this move. Our analysis centers on the degree towhich subjects deviate from the maximization of their pecuniaryrewards, as a response to others actions. Our results show nodifference in behavior between the two treatments. We also findevidence of the stability of subjects preferences with respectto their behavior over time and to the consistency of theirchoices as first and second mover.

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Report on the Strategic Sourcing Initiative implemented by the Department of Administrative Services (DAS)

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Background: Neuroticism is a personality component frequently found in anxious and depressive psychiatric disorders. The influence of neuroticism on negative emotions could be due to its action on stimuli related to fear and sadness, but this remains debated. Our goal was thus to better understand the impact of neuroticism through verbal and physiological assessment in response to stimuli inducing fear and sadness as compared to another negative emotion (disgust).¦Methods: Fifteen low neurotic and 18 high neurotic subjects were assessed on an emotional attending task by using film excerpts inducing fear, disgust, and sadness. We recorded skin conductance response (SCR) and corrugator muscle activity (frowning) as indices of emotional expression.¦Results: SCR was larger in high neurotic subjects than in low neurotics for fear relative to sadness and disgust. Moreover, corrugator activity and SCR were larger in high than in low neurotic subjects when fear was induced.¦Conclusion: After decades of evidence that individuals higher in neuroticism experience more intense emotional reactions to even minor stressors, our results indicate that they show greater SCR and expressive reactivity specifically to stimuli evoking fear rather than to those inducing sadness or disgust. Fear processing seems mainly under the influence of neuroticism. This modulation of autonomic activity by neurotics in response to threat/fear may explain their increased vulnerability to anxious psychopathologies such as PTSD (post traumatic stress disorder).

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We offer complete characterizations of the equilibrium outcomesof two prominent agenda voting institutions that are widely used in the democraticworld: the amendment, also known as the Anglo-American procedure,and the successive, or equivalently the Euro-Latin procedure. Our axiomaticapproach provides a proper understanding of these voting institutions, and allowscomparisons between them, and with other voting procedures.

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The aim of this study was to identify predictors of intentional use of the HIV risk reduction practices of serosorting, strategic positioning, and withdrawal before ejaculation during unprotected anal intercourse (UAI) with casual partners. A cross-sectional survey pertaining to the Swiss HIV behavioral surveillance system, using an anonymous self-administered questionnaire, was conducted in 2007 in a self-selected sample of men having sex with other men (MSM). Analysis was restricted to participants with UAI with casual partner(s) (N = 410). Logistic regression was used to estimate factors associated with intentional use of serosorting, strategic positioning, and withdrawal before ejaculation. In the previous 12 months, 71% of participants reported having UAI with a casual partner of different or unknown HIV-status. Of these, 47% reported practicing withdrawal, 38% serosorting, and 25% strategic positioning. In the 319 participants with known HIV-status, serosorting was associated with frequent Internet use to find partners (OR = 2.32), STI (OR = 2.07), and HIV testing in the past 12 months (OR = 1.81). Strategic positioning was associated with HIV-status (OR = 0.13) and having UAI with a partner of different or unknown HIV-status (OR = 3.57). Withdrawal was more frequently practiced by HIV-negative participants or participants reporting high numbers of sexual partners (OR = 2.48) and having UAI with a partner of unknown or different serostatus (OR = 2.08). Risk reduction practices are widely used by MSM, each practice having its own specificities. Further research is needed to determine the contextual factors surrounding harm reduction practices, particularly the strategic or opportunistic nature of their use.

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BACKGROUND: Up to 10% of the patients in whom suspected betalactam hypersensitivity (HS) has been excluded by skin and challenge tests report suspected allergic reactions during subsequent treatments with the same or very similar betalactams. It has been suggested that the reactions may result from a resensitization induced by the challenge performed at the time of the allergological work-up. However, most patients did not undergo a second allergological work-up, to determine if the reactions resulted from betalactam HS or not. OBJECTIVES: We aimed to determine if children diagnosed nonallergic to betalactams have tolerated subsequent treatments with the initially suspected and/or other betalactams, and, in case of a reaction, if the reaction resulted from betalactam HS. Methods: We sent a questionnaire concerning the clinical history of their children to the parents of 256 children previously diagnosed nonallergic to betalactams. A second allergological work-up was performed in the children reporting suspected allergic reactions during subsequent treatments with the same and/or other betalactams. Skin tests were performed with the soluble form of the suspected (or very similar) betalactams and other betalactams from the same and other classes. Skin test responses were assessed at 15-20 min (immediate), 6-8 h (semi-late) and 48-72 h (late). Oral challenge (OC) was performed in children with negative skin tests, either at the hospital (immediate and accelerated reactions), or at home (delayed reactions). RESULTS: A response was obtained from 141 children (55.3%). Forty-eight (34%) of those children had not been treated with the betalactams for whom a diagnosis of allergy had been ruled out previously. Seven (7.5%) of the 93 children who had been treated again reported suspected allergic reactions. Skin tests and OC were performed in six of those children, and gave negative results in five children. In one child previously diagnosed nonallergic to amoxicillin associated with clavulanic acid, we diagnosed a delayed HS to clavulanic acid and a serum sickness-like disease to cefaclor. Thus, the frequency of reactions resulting from betalactam HS in children with negative skin and challenge tests is very low, and does not exceed 2.1% (2/93) if we consider that the child which refused a second allergological work-up is really allergic to betalactams. CONCLUSION: Our results in a very large number of children show that reactions presumed to result from betalactam HS are rare in children in whom the diagnosis of betalactam allergy has been ruled out previously. Moreover, they suggest that, as shown for the initial reactions, most of the reactions during subsequent treatments are rather a consequence of the infectious diseases for whom betalactams have been prescribed than a result of betalactam HS. Finally, they suggest that the risk of resensitization by OC is very low, and do not support the notion that skin testing should be repeated in children diagnosed nonallergic to betalactams.

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Inflammasomes are protein complexes that form in response to pathogen-derived or host-derived stress signals. Their activation leads to the production of inflammatory cytokines and promotes a pyrogenic cell death process. The massive release of inflammatory mediators that follows inflammasome activation is a key event in alarming innate immune cells. Growing evidence also highlights the role of inflammasome-dependent cytokines in shaping the adaptive immune response, as exemplified by the capacity of IL-1β to support Th17 responses, or by the finding that IL-18 evokes antigen-independent IFN-γ secretion by memory CD8(+) T cells. A deeper understanding of these mechanisms and on how to manipulate this powerful inflammatory system therefore represents an important step forward in the development of improved vaccine strategies.

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Background: To enhance the induction of insert specific immune responses, a new generation of replication competent poxvirus vectors was designed and evaluated against non-replicating poxvirus vectors in a HIV vaccine study in non human primates.Methods: Rhesus macaques were immunized with either the non-replicating variant NYVAC-GagPolNef HIV-1 clade C or the replicating NYVAC-GagPolNef-C-KC, boosted with HIVGag- PolEnv-SLP and immune responses were monitored.Results: Gag-specific T-cell responses were only detected in animals immunized with the replicating NYVAC-GagPolNef-C-KC variant. Further enhancement and broadening of the immune response was studied by boosting the animals with novel T-cell immunogens HIVconsv synthetic long peptides (SLP), which direct vaccine-induced responses to the most conserved regions of HIV and contain both CD4 T-helper and CD8 CTL epitopes. The adjuvanted (Montanide ISA-720) SLP divided into subpools and delivered into anatomically separate sites enhanced the Gag-specific T-cell responses in 4 out of 6 animals, to more than 1000 SFC/106 PBMC in some animals. Furthermore, the SLP immunization broadened the immune response in 4 out of 6 animals to multiple Pol epitopes. Even Env-specific responses, to which the animals had not been primed, were induced by SLP in 2 out of 6 animals.Conclusion: This new immunization strategy of priming with replicating competent poxvirus NYVAC-HIVGagPolNef and boosting with HIVGagPolEnv-SLP, induced strong and broad Tcell responses and provides a promising new HIV vaccine approach. This study was performed within the Poxvirus T-cell Vaccine Discovery Consortium (PTVDC) which is part of the CAVD program.

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Inflammasome-mediated IL-1beta production is central to the innate immune defects that give rise to certain autoinflammatory diseases and may also be associated with the generation of IL-17-producing CD4(+) T (Th17) cells that mediate autoimmunity. However, the role of the inflammasome in driving adaptive immunity to infection has not been addressed. In this article, we demonstrate that inflammasome-mediated IL-1beta plays a critical role in promoting Ag-specific Th17 cells and in generating protective immunity against Bordetella pertussis infection. Using a murine respiratory challenge model, we demonstrated that the course of B. pertussis infection was significantly exacerbated in IL-1R type I-defective (IL-1RI(-/-)) mice. We found that adenylate cyclase toxin (CyaA), a key virulence factor secreted by B. pertussis, induced robust IL-1beta production by dendritic cells through activation of caspase-1 and the NALP3-containing inflammasome complex. Using mutant toxins, we demonstrate that CyaA-mediated activation of caspase-1 was not dependent on adenylate cyclase enzyme activity but was dependent on the pore-forming capacity of CyaA. In addition, CyaA promoted the induction of Ag-specific Th17 cells in wild-type but not IL-1RI(-/-) mice. Furthermore, the bacterial load was enhanced in IL-17-defective mice. Our findings demonstrate that CyaA, a virulence factor from B. pertussis, promotes innate IL-1beta production via activation of the NALP3 inflammasome and, thereby, polarizes T cell responses toward the Th17 subtype. In addition to its known role in subverting host immunity, our findings suggest that CyaA can promote IL-1beta-mediated Th17 cells, which promote clearance of the bacteria from the respiratory tract.

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