748 resultados para Regulatory Interventions


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Host-cell factor 1 (HCF-1) is an unusual transcriptional regulator that undergoes a process of proteolytic maturation to generate N- (HCF-1(N)) and C- (HCF-1(C)) terminal subunits noncovalently associated via self-association sequence elements. Here, we present the crystal structure of the self-association sequence 1 (SAS1) including the adjacent C-terminal HCF-1 nuclear localization signal (NLS). SAS1 elements from each of the HCF-1(N) and HCF-1(C) subunits form an interdigitated fibronectin type 3 (Fn3) tandem repeat structure. We show that the C-terminal NLS recruited by the interdigitated SAS1 structure is required for effective formation of a transcriptional regulatory complex: the herpes simplex virus VP16-induced complex. Thus, HCF-1(N)-HCF-1(C) association via an integrated Fn3 structure permits an NLS to facilitate formation of a transcriptional regulatory complex.

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Transforming growth factor beta (TGF-beta) has been shown to be a central immunomodulator used by leishmaniae to escape effective mechanisms of protection in human and murine infections with these parasites. However, all the information is derived from studies of established infection, while little is known about TGF-beta production in response to Leishmania stimulation in healthy subjects. In this study, TGF-beta1 production was demonstrated in peripheral blood mononuclear cells from healthy subjects never exposed to leishmaniae in response to live Leishmania guyanensis, and the TGF-beta1-producing cells were described as a distinct subpopulation of CD4(+) CD25(+) regulatory T cells. The suppressive properties of CD4(+) CD25(+) T cells were demonstrated in vitro by their inhibition of production of interleukin 2 (IL-2) and IL-10 by CD4(+) CD25(-) T cells in the presence of either anti-CD3 or L. guyanensis. Although neutralization of TGF-beta1 did not reverse the suppressive activity of CD4(+) CD25(+) T cells activated by anti-CD3, it reversed the suppressive activity of CD4(+) CD25(+) T cells activated by L. guyanensis. Altogether our data demonstrated that TGF-beta1 is involved in the suppressive activity of L. guyanensis-stimulated CD4(+) CD25(+) T cells from healthy controls.

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Pseudomonas fluorescens strain CHA0 protects plants from various root diseases. Antibiotic metabolites synthesized by this strain play an important role in disease suppression; their production is mediated by the global activator gene gacA. Here we show by complementation that the gacA gene is also essential for the expression of two extracellular enzymes in P. fluorescens CHA0: phospholipase C and a 47-kDa metalloprotease. In contrast, the production of another exoenzyme, lipase, is not regulated by the gacA gene. Protease, phospholipase and antibiotics of P. fluorescens are all known to be optimally produced at the end of exponential growth; thus, the gacA gene appears to be a general stationary-phase regulator.

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Summary : Control of pancreatic ß-cell mass and function by gluco-incretin hormones: Identification of novel regulatory mechanisms for the treatment of diabetes The ß-cells of islets of Langerhans secrete insulin to reduce hyperglycemia. The number of pancreatic islet ß-cells and their capacity to secrete insulin is modulated in normal physiological conditions to respond to the metabolic demand of the organism. A failure of the endocrine pancreas to maintain an adequate insulin secretory capacity due to a reduced ß-cell number and function underlies the pathogenesis of both type 1 and type 2 diabetes. The molecular mechanisms controlling the glucose competence of mature ß-cells, i.e., the magnitude of their insulin secretion response to glucose, ß-cell replication, their differentiation from precursor cells and protection against apoptosis are poorly understood. To investigate these mechanisms, we studied the effects on ß-cells of the gluco-incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) which are secreted by intestinal endocrine cells after food intake. Besides acutely potentiating glucose-stimulated insulin secretion, these hormones induce ß-cell differentiation from precursor cells, stimulate mature ß-cell replication, and protect them against apoptosis. Therefore, understanding the molecular basis for gluco-incretin action may lead to the uncovering of novel ß-cell regulatory events with potential application for the treatment or prevention of diabetes. Islets from mice with inactivation of both GIP and GLP-1 receptor genes (dK0) present a defect in glucose-induced insulin secretion and are more sensitive than control islets to cytokine-induced apoptosis. To search for regulatory genes, that may control both glucose competence and protection against apoptosis, we performed comparative transcriptomic analysis of islets from control and dK0 mice. We found a strong down-regulation of the IGF1 Rexpression in dK0 islets. We demonstrated in both a mouse insulin-secreting cell line and primary islets, that GLP-1 stimulated IGF-1R expression and signaling. Importantly, GLP-1induced IGF-1R-dependent Akt phosphorylation required active secretion, indicating the presence of an autocrine activation mechanism. We further showed that activation of IGF-1R signaling was dependent on the secretion of IGF-2 and IGF-2 expression was regulated by nutrients. Finally, we demonstrated that the IGF-Z/IGF-1R autocrine loop was required for GLP-1 i) to protect ß-cells against cytokine-induced apoptosis, ii) to enhance their glucose competence and iii) to increase ß-cell proliferation. Résumé : Contrôle de la masse des cellules ß pancréatiques et de leur fonction par les hormones glucoincrétines: Identification de nouveaux mécanismes régulateurs pour le traitement du diabète Les cellules ß des îlots de Langerhans sécrètent l'insuline pour diminuer l'hyperglycémie. Le nombre de cellules ß et leur capacité à sécréter l'insuline sont modulés dans les conditions physiologiques normales pour répondre à la demande métabolique de l'organisme. Un échec du pancréas endocrine à maintenir sa capacité sécrétoire d'insuline dû à une diminution du nombre et de la fonction des cellules ß conduit au diabète de type 1 et de type 2. Les mécanismes moléculaires contrôlant la compétence au glucose des cellules ß matures, tels que, l'augmentation de la sécrétion d'insuline en réponse au glucose, la réplication des cellules ß, leur différentiation à partir de cellules précurseurs et la protection contre l'apoptose sont encore peu connus. Afin d'examiner ces mécanismes, nous avons étudié les effets sur les cellules ß des hormones gluco-incrétines, glucose-dépendent insulinotropic polypeptide (G1P) et glucagon-like peptide-1 (GLP-1) qui sont sécrétées par les cellules endocrines de l'intestin après la prise alimentaire. En plus de potentialiser la sécrétion d'insuline induite par le glucose, ces hormones induisent la différentiation de cellules ß à partir de cellules précurseurs, stimulent leur prolifération et les protègent contre l'apoptose. Par conséquent, comprendre les mécanismes d'action des gluco-incrétines permettrait de découvrir de nouveaux processus régulant les cellules ß avec d'éventuelles applications dans le traitement ou la prévention du diabète. Les îlots de souris ayant une double inactivation des gènes pour les récepteurs du GIP et du GLP-1 (dK0) présentent un défaut de sécrétion d'insuline stimulée par le glucose et une sensibilité accrue à l'apoptose induite par les cytokines. Afin de déterminer les gènes régulés, qui pourraient contrôler à la fois la compétence au glucose et la protection contre l'apoptose, nous avons effectué une analyse comparative transcriptomique sur des îlots de souris contrôles et dKO. Nous avons constaté une forte diminution de l'expression d'IGF-1R dans les îlots dKO. Nous avons démontré, à la fois dans une lignée cellulaire murine sécrétant l'insuline et dans îlots primaires, que le GLP-1 stimulait l'expression d'IGF-1R et sa voie de signalisation. Par ailleurs, la phosphorylation d'Akt dépendante d'IGF1-R induite parle GLP-1 nécessite une sécrétion active, indiquant la présence d'un mécanisme d'activation autocrine. Nous avons ensuite montré que l'activation de la voie de signalisation d'IGF-1R était dépendante de la sécrétion d'IGF-2, dont l'expression est régulée par les nutriments. Finalement, nous avons démontré que la boucle autocrine IGF-2/IGF-1R est nécessaire pour le GLP-1 i) pour protéger les cellules ß contre l'apoptose induite par les cytokines, ii) pour améliorer la compétence au glucose et iii) pour augmenter la prolifération des cellules ß. Résumé tout public : Contrôle de la masse des cellules ß pancréatiques et de leur fonction par les hormones gluco-incrétines: Identification de nouveaux mécanismes régulateurs pour le traitement du diabète Chez les mammifères, la concentration de glucose sanguine (glycémie) est régulée et maintenue à une valeur relativement constante d'environ 5 mM. Cette régulation est principalement contrôlée par 2 hormones produites par les îlots pancréatiques de Langerhans: l'insuline sécrétée par les cellules ß et le glucagon sécrété par les cellules a. A la suite d'un repas, l'augmentation de la glycémie entraîne la sécrétion d'insuline ce qui permet le stockage du glucose dans le foie, les muscles et le tissu adipeux afin de diminuer le taux de glucose circulant. Lors d'un jeûne, la diminution de la glycémie permet la sécrétion de glucagon favorisant alors la production de glucose par le foie, normalisant ainsi la glycémie. Le nombre de cellules ß et leur capacité sécrétoire s'adaptent aux variations de la demande métabolique pour assurer une normoglycémie. Une destruction complète ou partielle des cellules ß conduit respectivement au diabète de type 1 et de type 2. Bien que l'augmentation de la glycémie soit le facteur stimulant de la sécrétion d'insuline, des hormones gluco-incrétines, principalement le GLP-1 (glucagon-like peptide-1) et le GIP (glucose-dependent insulinotropic polypeptide) sont libérées par l'intestin en réponse aux nutriments (glucose, acides gras) et agissent au niveau des cellules ß, potentialisant la sécrétion d'insuline induite par le glucose, stimulant leur prolifération, induisant la différentiation de cellules précurseurs en cellules ß matures et les protègent contre la mort cellulaire (apoptose). Afin d'étudier plus en détail ces mécanismes, nous avons généré des souris déficientes pour les récepteurs du GIP et du GLP-l. Les îlots pancréatiques de ces souris présentent un défaut de sécrétion d'insuline stimulée par le glucose et une sensibilité accrue à l'apoptose par rapport aux îlots de souris contrôles. Nous avons donc cherché les gènes régulés pas ces hormones contrôlant la sécrétion d'insuline et la protection contre l'apoptose. Nous avons constaté une forte diminution de l'expression du récepteur à l'IGF-1 (IGF-1R) dans les îlots de souris déficientes pour les récepteurs des gluco-incrétines. Nous avons démontré dans un model de cellules ß en culture et d'îlots que le GLP-1 augmentait l'expression d'IGF-1R et la sécrétion de son ligand (IGF-2) permettant l'activation de la voie de signalisation. Finalement, nous avons montré que l'activation de la boucle IGF-2/IGF-1R induite par le GLP-1 était nécessaire pour la protection contre l'apoptose, l'augmentation de la sécrétion et la prolifération des cellules ß.

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STUDY OBJECTIVE: Frequent users of emergency departments (EDs) are a relatively small group of vulnerable patients accounting for a disproportionally high number of ED visits. Our objective is to perform a systematic review of the type and effectiveness of interventions to reduce the number of ED visits by frequent users. METHODS: We searched MEDLINE, EMBASE, CINAHL, PsychINFO, the Cochrane Library, and ISI Web of Science for randomized controlled trials, nonrandomized controlled trials, interrupted time series, and controlled and noncontrolled before-and-after studies describing interventions targeting adult frequent users of EDs. Primary outcome of interest was the reduction in ED use. We also explored costs analyses and various clinical (alcohol and drug use, psychiatric symptoms, mortality) and social (homelessness, insurance status, social security support) outcomes. RESULTS: We included 11 studies (3 randomized controlled trials, 2 controlled and 6 noncontrolled before-and-after studies). Heterogeneity in both study designs and definitions of frequent users precluded meta-analyses of the results. The most studied intervention was case management (n=7). Only 1 of 3 randomized controlled trials showed a significant reduction in ED use compared with usual care. Six of the 8 before-and-after studies reported a significant reduction in ED use, and 1 study showed a significant increase. ED cost reductions were demonstrated in 3 studies. Social outcomes such as reduction of homelessness were favorable in 3 of 3 studies, and clinical outcomes trended toward positive results in 2 of 3 studies. CONCLUSION: Interventions targeting frequent users may reduce ED use. Case management, the most frequently described intervention, reduced ED costs and seemed to improve social and clinical outcomes. It appears to be beneficial to patients and justifiable for hospitals to implement case management for frequent users in the framework of a clear and consensual definition of frequent users and standardized outcome measures.

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The currently available immunosuppressive agents applied in human transplantation medicine are highly potent in the protection from acute allograft rejection. However, long-term allograft survival is still poor as these drugs fail to sufficiently prevent chronic allograft rejection. Naturally occurring regulatory T cells have been postulated as the key players to establish long-lasting transplantation tolerance. Thus, the development of immunosuppressive regimens which shift the pathological balance of cytopathic versus regulatory T cells of human allograft recipients towards a protective T-cell composition is a promising approach to overcome limitations of current transplantation medicine. Thirty-three patients that received rapamycin (RPM) or calcineurin inhibitor treatment following lung transplantation were included and their T-cell compartments analysed. Twelve healthy volunteers without history of lung disease served as controls. In this article, we show that treatment of human lung transplant recipients with RPM is associated with an increased frequency of regulatory T cells, as compared with treatment with calcineurin inhibitors or to healthy controls. Moreover, regulatory T cells during treatment with RPM were CD62Lhigh, a phenotype that displayed an enhanced immunosuppressive capacity ex vivo. Our data support the use of RPM in human lung transplant recipients and undertaking of further prospective studies evaluating its impact on allograft and patient survival.

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Report for Iowa Utilities Board

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Transcription factors act in concert to induce lineage commitment towards Th1, Th2, or T regulatory (Treg) cells, and their counter-regulatory mechanisms were shown to be critical for polarization between Th1 and Th2 phenotypes. FOXP3 is an essential transcription factor for natural, thymus-derived (nTreg) and inducible Treg (iTreg) commitment; however, the mechanisms regulating its expression are as yet unknown. We describe a mechanism controlling iTreg polarization, which is overruled by the Th2 differentiation pathway. We demonstrated that interleukin 4 (IL-4) present at the time of T cell priming inhibits FOXP3. This inhibitory mechanism was also confirmed in Th2 cells and in T cells of transgenic mice overexpressing GATA-3 in T cells, which are shown to be deficient in transforming growth factor (TGF)-beta-mediated FOXP3 induction. This inhibition is mediated by direct binding of GATA3 to the FOXP3 promoter, which represses its transactivation process. Therefore, this study provides a new understanding of tolerance development, controlled by a type 2 immune response. IL-4 treatment in mice reduces iTreg cell frequency, highlighting that therapeutic approaches that target IL-4 or GATA3 might provide new preventive strategies facilitating tolerance induction particularly in Th2-mediated diseases, such as allergy.

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BACKGROUND: Anti-CD154 (MR1) monoclonal antibody (mAb) and rapamycin (RAPA) treatment both improve survival of rat-to-mouse islet xenograft. The present study investigated the effect of combined RAPA/MR1 treatment on rat-to-mouse islet xenograft survival and analyzed the role of CD4(+)CD25(+)Foxp3(+) T regulatory cells (Treg) in the induction and maintenance of the ensuing tolerance. METHODOLOGY/PRINCIPAL FINDINGS: C57BL/6 mice were treated with MR1/RAPA and received additional monoclonal anti-IL2 mAb or anti CD25 mAb either early (0-28 d) or late (100-128 d) post-transplantation. Treg were characterised in the blood, spleen, draining lymph nodes and within the graft of tolerant and rejecting mice by flow cytometry and immunohistochemistry. Fourteen days of RAPA/MR1 combination therapy allowed indefinite islet graft survival in >80% of the mice. Additional administration of anti-IL-2 mAb or depleting anti-CD25 mAb at the time of transplantation resulted in rejection (100% and 89% respectively), whereas administration at 100 days post transplantation lead to lower rejection rates (25% and 40% respectively). Tolerant mice showed an increase of Treg within the graft and in draining lymph nodes early post transplantation, whereas 100 days post transplantation no significant increase of Treg was observed. Rejecting mice showed a transient increase of Treg in the xenograft and secondary lymphoid organs, which disappeared within 7 days after rejection. CONCLUSIONS/SIGNIFICANCES: These results suggest a critical role for Treg in the induction phase of tolerance early after islet xenotransplantation. These encouraging data support the need of developing further Treg therapy for overcoming the species barrier in xenotransplantation.

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Background: Recent reviews of randomized control trials have shown that pharmacist interventions improve cardiovascular diseases (CVD) risk factors in outpatients. Various interventions were evaluated in different settings, and a substantial heterogeneity was observed in the effect estimates. To better express uncertainties in the effect estimates, prediction intervals (PI) have been proposed but are, however, rarely reported. Objective: Pooling data from two systematic reviews, we estimated the effect of pharmacist interventions on systolic blood pressure (BP), computed PI, and evaluated potential causes of heterogeneity. Methods: Data were pooled from systematic reviews assessing the effect of pharmacist interventions on CVD risk factors in patients with or without diabetes, respectively. Effects were estimated using random effect models. Results: Systolic BP was the outcome in 31 trials including 12 373 patients. Pharmacist interventions included patient educational interventions, patient-reminder systems, measurement of BP, medication management and feedback to physician, or educational intervention to health care professionals. Pharmacist interventions were associated with a large reduction in systolic BP (-7.5 mmHg; 95% CI: -9.0 to -5.9). There was a substantial heterogeneity (I2: 66%). The 95% PI ranged from -13.9 to -1.0 mmHg. The effect tended to be larger if the intervention was conducted in a community pharmacy and if the pharmacist intervened at least monthly. Conclusion: On average, the effect of pharmacist interventions on BP was substantial. However, the wide PI suggests that the effect differed between interventions, with some having modest effects and others very large effects on BP. Part of the heterogeneity could be due to differences in the setting and in the frequency of the interventions.

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Recommendations on preventive services rarely mention how to apply them to older people. Even though general criteria (prevalence of disease, quality of screening tests) that influence screening's efficacy remain important, appropriateness of screening in older persons depends much more on individual criteria, such as comorbidity, functional status, and life expectancy. More than with any other age group, patients preferences regarding future investigation and treatment guide the clinical decision. This article focuses on primary and secondary prevention, and discusses specific criteria to consider in each patient. A table summarizes the appropriate recommendations.

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BACKGROUND: Control of blood pressure (BP) remains a major challenge in primary care. Innovative interventions to improve BP control are therefore needed. By updating and combining data from 2 previous systematic reviews, we assess the effect of pharmacist interventions on BP and identify potential determinants of heterogeneity. METHODS AND RESULTS: Randomized controlled trials (RCTs) assessing the effect of pharmacist interventions on BP among outpatients with or without diabetes were identified from MEDLINE, EMBASE, CINAHL, and CENTRAL databases. Weighted mean differences in BP were estimated using random effect models. Prediction intervals (PI) were computed to better express uncertainties in the effect estimates. Thirty-nine RCTs were included with 14 224 patients. Pharmacist interventions mainly included patient education, feedback to physician, and medication management. Compared with usual care, pharmacist interventions showed greater reduction in systolic BP (-7.6 mm Hg, 95% CI: -9.0 to -6.3; I(2)=67%) and diastolic BP (-3.9 mm Hg, 95% CI: -5.1 to -2.8; I(2)=83%). The 95% PI ranged from -13.9 to -1.4 mm Hg for systolic BP and from -9.9 to +2.0 mm Hg for diastolic BP. The effect tended to be larger if the intervention was led by the pharmacist and was done at least monthly. CONCLUSIONS: Pharmacist interventions - alone or in collaboration with other healthcare professionals - improved BP management. Nevertheless, pharmacist interventions had differential effects on BP, from very large to modest or no effect; and determinants of heterogeneity could not be identified. Determining the most efficient, cost-effective, and least time-consuming intervention should be addressed with further research.

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Regulatory Plan for Fiscal Year 2005