1000 resultados para Una virus


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Estudi realitzat a partir d’una estada Istituto di Storia dell'Europa Mediterranea - CNR, Itàlia, entre 2006 i 2008. L’objectiu principal d’aquest projecte és profunditzar en el coneixement de les relacions de poder que es teixeixen entre la Monarquia, les assemblees de Corts i les ciutats de la Corona d’Aragó durant el regnat d’Alfons el Magnànim. La recerca ha permès elaborar un estudi comparatiu de les dites relacions entre els estats italians i els territoris peninsulars de l’esmentada Corona, donant un pes rellavant a la documentació urbana dels territoris italians, escassament estudiada fins al moment. Un altre punt clau d’aquest estudi és l’anàlisi de la figura del síndic enviat a corts, essent el representant municipal a les dites assemblees el nexe d’unió entre la ciutat, els tres estats i el rei. Des del punt de vista metodològic, s’ha prioritzat l’estudi documental i bibliogràfic sobre Sardenya, si bé també s'ha procedit a un estudi sobre les fonts del Regne de Sicília i de Nàpols. Els resultats d’aquest treball es concentren especialment en la posició econòmica, prosopografia i estratègies de poder de l’elit que controla el govern municipal de les ciutas reials, així mateix com en el tipus de relació que aquest grup social estableix amb la monarquia i l’administració reial. Les conclusions assenyalen que el poder de la monarquia sobre les seves ciutats a Sardenya durant aquest període és major respecte a altres estats ibèrics de la Corona, en especial Catalunya. D’altra banda, l’elit que controla el govern urbà presenta un grau d’enobliment també superior, lligat al fet de la recent conquesta de l’illa. Els sistemes electius dins del municipi són pràcticament idèntics als catalans (...)

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Report for the scientific sojourn carried out at the Institut de Biologia Molecular de Barcelona of the CSIC –state agency – from april until september 2007. Topoisomerase I is an essential nuclear enzyme that modulates the topological status of DNA, facilitating DNA helix unwinding during replication and transcription. We have prepared the oligonucleotide-peptide conjugate Ac-NLeu-Asn-Tyr(p-3’TTCAGAAGC5’)-LeuC-CONH-(CH2)6-OH as model compound for NMR studies of the Topoisomerase I- DNA complex. Special attention was made on the synthetic aspects for the preparation of this challenging compound especially solid supports and protecting groups. The desired peptide was obtained although we did not achieve the amount of the conjugate needed for NMR studies. Most probably the low yield is due to the intrinsic sensitive to hydrolysis of the phosphate bond between oligonucleotide and tyrosine. We have started the synthesis and the structural characterization of oligonucleotides carrying intercalating compounds. At the present state we have obtained model duplex and quadruplex sequences modified with acridine and NMR studies are underway. In addition to this project we have successfully resolved the structure of a fusion peptide derived from hepatitis C virus envelope synthesized by the group of Dr. Haro and we have synthesized and started the characterization of a modified G-quadruplex.

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Report for the scientific sojourn carried out at the University of St. Andrews, United Kingdom, from November 2007 until January 2008. Therapeutic transgene expression is a valuable strategy to counteract the limitations associated with oncolytic adenoviruses. Late phase expression is desirable to avoid early cell death for proper virus production. In this 3 months-collaboration, we have constructed a late expression system based on ribosome skipping downstream fiber protein and compared it with a splicing-based method of late gene expression. Despite expressing high amounts of the transgene when utilizing the ribosome skipping-system, flow cytomety assays indicate a delayed transgene-expression kinetics compared with the splicing-based one. Furthermore, when using the ribosome skipping system not only fiber protein expression is more altered but also viral production. These results suggest splicing-based expression strategy as a more suitable system for expression of transgenes late in the viral life cycle of an oncolytic adenovirus.

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OBJECTIVE: To describe the effect of HAART on Kaposi sarcoma herpes virus (KSHV) antibody response and viremia among HIV-positive MSM. DESIGN: A follow-up study of 272 HIV-positive MSM (including 22 with Kaposi sarcoma) who first initiated HAART between January 1996 and July 2004 in the Swiss HIV Cohort Study. METHODS: For each individual, two serum samples, one at HAART initiation and another 24 months later, were tested for latent and lytic KSHV antibodies using immunofluorescence assays, and for KSHV viremia using PCR. Factors associated with changes in KSHV antibody titers and viremia were evaluated. RESULTS: At HAART initiation, 69.1 and 75.0% of patients were seropositive to latent and lytic KSHV antibodies, respectively. Seropositivity was associated with the presence of Kaposi sarcoma, older age, lower CD8 cell count and higher CD4/CD8 ratio. Prevalence of KSHV viremia at HAART initiation was 6.4%, being significantly higher among patients with Kaposi sarcoma (35.0%), and those with HIV viral loads 100 000 copies/ml (11.7%) or higher. At 24-month follow-up, geometric mean titers (GMTs) among KSHV seropositive patients increased and antibody seroprevalence was higher. Having Kaposi sarcoma and/or CD4 cell counts less than 50 cells/microl at HAART initiation was associated both with higher probability for antibody titers to increase (including seroconversion) and larger increases in GMTs. Only one of 17 viremic patients at HAART initiation had viremia at 24-month follow-up. CONCLUSION: HAART increases KSHV-specific humoral immune response and clearance of viremia among HIV-infected MSM, consistent with the dramatic protection offered by HAART against Kaposi sarcoma.

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En el presente estudio nos aproximamos al cálculo del impacto de una política de supresión de peajes en España. Se estima una función de demanda de autopistas de peaje, utilizando un modelo de datos de panel con efectos fijos. Los resultados confirman que las elasticidades son mayores que el promedio encontrado en la literatura, la razón es la existencia y calidad de una vía alternativa. En cuanto al impacto de la política, los resultados sugieren un incremento del tráfico en las autopistas de 43,40% en relación con 2007. El cambio del bienestar de los usuarios se estima en €1497,58 millones (en comparación con 2007)

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Interleukin 1 beta (IL-1 beta) is a potent proinflammatory factor during viral infection. Its production is tightly controlled by transcription of Il1b dependent on the transcription factor NF-kappaB and subsequent processing of pro-IL-1 beta by an inflammasome. However, the sensors and mechanisms that facilitate RNA virus-induced production of IL-1 beta are not well defined. Here we report a dual role for the RNA helicase RIG-I in RNA virus-induced proinflammatory responses. Whereas RIG-I-mediated activation of NF-kappaB required the signaling adaptor MAVS and a complex of the adaptors CARD9 and Bcl-10, RIG-I also bound to the adaptor ASC to trigger caspase-1-dependent inflammasome activation by a mechanism independent of MAVS, CARD9 and the Nod-like receptor protein NLRP3. Our results identify the CARD9-Bcl-10 module as an essential component of the RIG-I-dependent proinflammatory response and establish RIG-I as a sensor able to activate the inflammasome in response to certain RNA viruses.

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La problemática de la investigación se plantea en el contexto de la filosofía trascendental de Kant, en relación al modo en que es en general posible para nosotros representarnos el ámbito de la moralidad. Nuestra comprensión natural o preteórica del funcionamiento del lenguaje parece llevarnos a entender el significado de nuestras palabras en términos de la relación que se establece entre el signo lingüístico y el objeto: nuestros términos lingüísticos están en el lugar del objeto extralingüístico a que refieren y que constituye su significado. A nuestro modo de ver, la afirmación kantiana relativa a que todo nuestro conocimiento comienza con la experiencia, es decir, con aquello que procede de los sentidos, parece estar apuntando a esta intuición fundamental. Ahora bien, la cuestión que cabe plantearse es: de acuerdo con este modelo de significación, ¿cuál es el significado de nuestros términos morales? Si, con Kant, aceptamos que el concepto de deber moral exige el cumplimiento (u omisión) incondicionado de una acción y que, precisamente por las exigencias de universalidad y necesidad que le son inherentes, tal concepto es inderivable de la experiencia, cabe preguntarse cuál es el significado del concepto de deber en sentido moral (y, en general, de los términos morales) y de qué manera somos capaces de representárnoslo. Mi investigación ha pretendido esclarecer precisamente en qué sentido debe entenderse la afirmación kantiana de que en la reflexión sobre la corrección moral de nuestras acciones, para representarnos las exigencias de universalidad y necesidad que son propias del concepto de deber moral, nos servimos analógicamente del concepto de naturaleza, así como analizar la plausibilidad de la propuesta kantiana misma.

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Les tècniques de clustering poden ajudar a reduir la supervisió en processos d'obtenció de patrons per a Extracció d'Informació. En aquest treball, que abarca un període de 4 anys de recerca, es comença per estudiar la representació de documents més adequada per a la tasca de clustering. Per tal d'evitar els biaixos dels mètodes individuals de clustering, es consideren mètodes de clustering conjunt. S'exploren diversos mètodes de combinació supervisada, i s'hi afegeixen estratègies automàtiques per a determinar el nombre de clusters de la combinació. També es consideren mecanismes per a obtenir clusterings conjunts ponderats, així com estratègies de combinació no supervisada. Finalment, els resultats del clustering s'utilitzen en un sistema d'adquisició de patrons per a substituir els elements de supervisió humana. Totes aquestes estratègies i mètodes s'avaluen en tasques de clustering de documents i adquisició de patrons usant dades reals. Es comprova que els mots com representació de documents superen altres models per a la tasca de clustering, així com que el clustering conjunt supera les limitacions dels clusterings individuals, i que les estratègies no supervisades d'adquisició de patrons obtenen resultats competitius respecte a les estratègies supervisades.

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B cells are the primary targets of infection for mouse mammary tumor virus (MMTV). However, for productive retroviral infection, T cell stimulation through the virally-encoded superantigen (SAG) is necessary. It activates B cells and leads to cell division and differentiation. To characterize the role of B cell differentiation for the MMTV life cycle, we studied the course of infection in transgenic mice deficient for CD28/CTLA4-B7 interactions (mCTLA4-H gamma 1 transgenic mice). B cell infection occurred in CTLA4-H gamma 1 transgenic mice as integrated proviral DNA could be detected in draining lymph node cells early after infection by polymerase chain reaction analysis. In mice expressing I-E, B cells were able to present the viral SAG efficiently to V beta 6+ T cells. These cells expanded specifically and were triggered to express the activation marker CD69. Further stages of progression of infection appeared to be defective. Kinetics experiments indicated that T and B cell stimulation stopped more rapidly than in control mice. B cells acquired an activated CD69+ phenotype, were induced to produce IgM but only partially switched to IgG secretion. Finally, the dissemination of infected cells to other lymph nodes and spleen was reduced and the peripheral deletion of V beta 6+ T cells was minimal. In contrast, in mice lacking I-E, T cell stimulation was also impaired and B cell activation undetectable. These data implicate B7-dependent cellular interactions for superantigenic T cell stimulation by low-affinity TCR ligands and suggest a role of B cell differentiation in viral dissemination and peripheral T cell deletion.