882 resultados para Influenza viruses


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Mouse mammary tumor virus (MMTV) encodes a superantigen that is important for viral infectivity in vivo. To determine whether superantigen function was required for infection by milk-borne MMTV, we created HYB PRO/Cla transgenic mice. These mice produced a full-length, packaged viral RNA with a frameshift mutation that caused premature termination of the superantigen protein. Young HYB PRO/Cla mice showed no deletion of their cognate V beta 14+ T cells, although they shed virus in their milk. The nontransgenic offspring of the HYB PRO/Cla mice were infected with this virus, since transgene-specific viral transcripts were detected in their mammary glands. Surprisingly, these offspring demonstrated the progressive deletion of V beta 14+ T cells characteristic of exogenous MMTV (C3H) infection. Sequence analysis demonstrated that these newly acquired viruses had reconstituted superantigen open reading frames resulting from recombination between the HYB PRO/Cla and endogenous Mtv-1 proviral RNAs. Thus, there is selection during the infection process for MMTVs with functional superantigen genes.

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We assembled a DNA clone containing the 11,161-nt sequence of the prototype rhabdovirus, vesicular stomatitis virus (VSV), such that it could be transcribed by the bacteriophage T7 RNA polymerase to yield a full-length positive-strand RNA complementary to the VSV genome. Expression of this RNA in cells also expressing the VSV nucleocapsid protein and the two VSV polymerase subunits resulted in production of VSV with the growth characteristics of wild-type VSV. Recovery of virus from DNA was verified by (i) the presence of two genetic tags generating restriction sites in DNA derived from the genome, (ii) direct sequencing of the genomic RNA of the recovered virus, and (iii) production of a VSV recombinant in which the glycoprotein was derived from a second serotype. The ability to generate VSV from DNA opens numerous possibilities for the genetic analysis of VSV replication. In addition, because VSV can be grown to very high titers and in large quantities with relative ease, it may be possible to genetically engineer recombinant VSVs displaying foreign antigens. Such modified viruses could be useful as vaccines conferring protection against other viruses.

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Para avaliar os benefícios da comunicação rápida ao clínico do diagnóstico de vírus respiratórios, foi analisado a viabilidade econômica de 2 testes, com o tempo de entrega de resultado em 2 horas para teste rápido e 48 horas para Biologia Molecular. As amostras coletadas foram processadas utilizando técnicas convencionais e os testes disponíveis no mercado local. Foram escolhidos dois testes rápidos pelo método de imunocromatografia para quatro parâmetros analíticos: Influenza A, Influenza H1N1, Influenza B e Vírus Sincicial Respiratório (RSV) e em Biologia Molecular um teste de RT-PCR multiplex com 25 patógenos entre vírus e bactérias. O tipo de amostra utilizada foi swab e lavado de nasofaringe. A população escolhida para o estudo foi paciente adulto, em tratamento de câncer, que necessita de uma resposta rápida já que a maioria se encontra com comprometimento do sistema imune por doença ou por tratamento. O estudo foi transversal, realizado entre os anos de 2012 e 2013, para avaliar a viabilidade econômica da introdução de testes de diagnóstico da infecção respiratória aguda de etiologia viral a partir de amostras de nasofaringe em pacientes com câncer atendidos no Centro de Atendimento de Oncologia Intercorrência (CAIO ), do Instituto do Câncer do Estado de São Paulo (ICESP), hospital público que atende exclusivamente Sistema Único de Saúde (SUS) e Hospital A.C. Camargo, que atende tanto a pacientes do SUS como da rede privada. O estudo incluiu 152 pacientes em tratamento para qualquer tipo de câncer, predominantemente do sexo feminino (81 mulheres e 70 homens) com idades entre 18-86 anos. Para participar do estudo o paciente era consultado e o critério para escolha do paciente foi ser portador de câncer, com história de febre (ainda que referida) acompanhada de tosse ou dor de garganta, tosse e sintomas respiratórios agudos, atendidos por protocolo padronizado que inclui avaliação na admissão, seguimento e manejo antimicrobiano. Para a avaliação econômica os pacientes foram classificados de acordo com o estado geral de saúde, se apresentavam bom estado de estado de saúde poderiam receber alta e faziam uso da medicação em casa evitando 5 dias de internação se recebessem algum resultado para Influenza ou RSV, no entanto os pacientes que apresentavam outro vírus, resultado negativo ou o estado geral era ruim permaneciam internados por 7 dias em observação e cuidados com medicação adequada. Foram realizadas análises econômicas em dois âmbitos: o sistema de saúde publico e o privado considerando o fator diminuição de dias de internação. A analise de Custo-benefício foi eficiente no Sistema privado mas inadequada para o SUS assim como, qualquer outra medida monetária já que os valores de reembolso do SUS estão defasados do custo de qualquer internação. A análise de Custo-efetividade que olha para outros fatores além do monetário foi efetiva nos dois sistemas que enfrentam falta de leitos além da condição de saúde do paciente de evitar a ingestão desnecessária de antibióticos, evitar os gastos do acompanhante, perda de dias de trabalho e estudo. Não houve correspondência de resultados dos testes rápidos com o multiplex de Biologia Molecular

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Objective. Describe acceptability of pandemic A(H1N1) influenza vaccination by Essential Community Workers (ECWs) from Alicante province (Spain) in January 2010. Evaluate the correlation with attitudes, beliefs, professional advice and information broadcasted by media. Method. In this cross-sectional study, face-to-face interviews were conducted with 742 ECWs to assess their attitudes towards vaccination against the pandemic influenza strain. A multivariable regression model was made to adjust the Odds Ratios (ORs). Results. Some ECWs reported having been vaccinated with seasonal vaccine, 21.5% (95%IC 18.6–24.9); only 15.4% (95%IC 12.8–18.4) with the pandemic one. ECWs vaccinated regularly against seasonal flu (OR 5.1; 95%IC 2.9–9.1), those who considered pandemic influenza as a severe or more serious disease than seasonal flu (OR 3.8; 95%IC 2.1–6.7) and those who never had doubts about vaccine safety (OR 3.7; 95%IC2.1–6.7) had a better acceptance of pandemic vaccine. Finally, 78.7% (95%IC 75.1–81.4) had doubts about pandemic vaccine's effectiveness. Conclusion. The vast amount of information provided by the media did not seem to be decisive to prevent doubts or to improve the acceptability of the vaccine in ECWs. Professional advice should be the focus of interest in future influenza vaccination campaigns. These results should be taken into account by health authorities.

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Influenza A virus assembly is an unclear process, whereby individual virion components form an infectious particle. The segmented nature of the influenza A genome imposes a problem to assembly because it requires packaging of eight distinct RNA particles (vRNPs). It also allows genome mixing from distinct parental strains, events associated with influenza pandemic outbreaks. It is important to public health to understand how segmented genomes assemble, a process that is dependent on the transport of components to assembly sites. Previously, it has been shown that vRNPs are carried by recycling endosome vesicles, resulting in a change of Rab11 distribution. Here, we describe that vRNP binding to recycling endosomes impairs recycling endosome function, by competing for Rab11 binding with family-interacting proteins, and that there is a causal relationship between Rab11 ability to recruit family-interacting proteins and Rab11 redistribution. This competition reduces recycling sorting at an unclear step, resulting in clustering of single- and double-membraned vesicles. These morphological changes in Rab11 membranes are indicative of alterations in protein and lipid homeostasis during infection. Vesicular clustering creates hotspots of the vRNPs that need to interact to form an infectious particle.

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A multicentre case-control study based on sentinel practitioner surveillance networks from seven European countries was undertaken to estimate the effectiveness of 2009-2010 pandemic and seasonal influenza vaccines against medically attended influenza-like illness (ILI) laboratory-confirmed as pandemic influenza A (H1N1) (pH1N1).

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Recent studies suggest an association between the Interferon Inducible Transmembrane 3 (IFITM3) rs12252 variant and the course of influenza infection. However, it is not clear whether the reported association relates to influenza infection severity. The aim of this study was to estimate the hospitalization risk associated with this variant in Influenza Like Illness (ILI) patients during the H1N1 pandemic influenza. A case-control genetic association study was performed, using nasopharyngeal/oropharyngeal swabs collected during the H1N1 pandemic influenza. Laboratory diagnosis of influenza infection was performed by RT-PCR, the IFITM3 rs12252 was genotyped by RFLP and tested for association with hospitalization. Conditional logistic regression was performed to calculate the confounder-adjusted odds ratio of hospitalization associated with IFITM3 rs12252. We selected 312 ILI cases and 624 matched non-hospitalized controls. Within ILI Influenza A(H1N1)pdm09 positive patients, no statistical significant association was found between the variant and the hospitalization risk (Adjusted OR: 0.73 (95%CI: 0.33–1.50)). Regarding ILI Influenza A(H1N1)pdm09 negative patients, CT/CC genotype carriers had a higher risk of being hospitalized than patients with TT genotype (Adjusted OR: 2.54 (95%CI: 1.54–4.19)). The IFITM3 rs12252 variant was associated with respiratory infection hospitalization but not specifically in patients infected with Influenza A(H1N1)pdm09.

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Background: Flu vaccine composition is reformulated on a yearly basis. As such, the vaccine effectiveness (VE) from previous seasons cannot be considered for subsequent years, and it is necessary to monitor the VE for each season. This study (MonitorEVA- monitoring vaccine effectiveness) intends to evaluate the feasibility of using the national influenza surveillance system (NISS) for monitoring the influenza VE. Material and methods: Data was collected within NISS during 2004 to 2014 seasons. We used a case-control design where laboratory confirmed incident influenza like illness (ILI) patients (cases) were compared to controls (ILI influenza negative). Eligible individuals consisted on all aged individuals that consult a general practitioner or emergency room with ILI symptoms with a swab collected within seven days of symptoms onset. VE was estimated as 1- odds ratio of being vaccinated in cases versus controls adjusted for age and month of onset by logistic regression. Sensitivity analyses were conducted to test possible effect of assumptions on vaccination status, ILI definition and timing of swabs (<3 days after onset). Results: During the 2004-2014 period, a total of 5302 ILI patients were collected but 798 ILI were excluded for not complying with inclusion criteria. After data restriction the sample size in both groups was higher than 148 individuals/ season; minimum sample size needed to detect a VE of at least 50% considering a level of significance of 5% and 80% power. Crude VE point estimates were under 45% in 2004/05, 2005/06, 2011/12 and 2013/14 season; between 50%-70% in 2006/07, 2008/09 and 2010/11 seasons, and above 70% in 2007/08 and 2012/13 season. From season 2006/07 to 2013/14, all crude VE estimates were statistically significant. After adjustment for age group and month of onset, the VE point estimates decreased and only 2008/09, 2012/13 and 2013/14 seasons were significant. Discussion and Conclusions: MonitorEVA was able to provide VE estimates for all seasons, including the pandemic, indicating if the VE was higher than 70% and less than 50%. When comparing with other observational studies, MonitorEVA estimates were comparable but less precise and VE estimates were in accordance with the antigenic match of the circulating virus/ vaccine strains. Given the sensitivity results, we propose a MonitorEVA based on: a) Vaccination status defined independently of number of days between vaccination and symptoms onset; b) use of all ILI data independent of the definition; c) stratification of VE according to time between onset and swab (< 3 and ≥3 days).

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L’obiettivo di questa tesi di Laurea è stato di analizzare gli scambi termici radiativi che si verificano all’interno di una stanza; per eseguire questa analisi si sono calcolati i fattori di vista Fij tra diversi punti (i) definiti tramite una griglia regolare posta all’interno della stanza e le superfici che vi si affacciano (j); tale griglia prevede 25 punti posti a 3 altezze diverse, per un totale di 75 punti. Dalla conoscenza delle temperature superficiali si sono ottenuti i valori di temperatura media radiante nei punti della griglia, e successivamente i valori degli indici di benessere PMV (voto medio previsto) e PPD (percentuale prevista di insoddisfatti), fissando i parametri necessari. Il calcolo dei fattori di vista è stato eseguito tramite il software TRISCO®, dopo averne confrontato i risultati forniti con COMSOL® e dopo aver valutato la correttezza di alcune approssimazioni. Il modello utilizzato nelle simulazioni è costituito da una stanza di 5x5x2,8 m, in cui sono stati fatti variare il numero e la posizione di alcuni elementi caratterizzanti, come finestre e radiatori, oltre a tipologia di elementi scaldanti e posizione e numero di pareti esterne, tramite la variazione delle temperature. In seguito si è analizzata la potenza scambiata per irraggiamento dagli elementi scaldanti, per poter riconoscere gli elementi responsabili dei maggiori contributi; nel caso di pavimento o soffitto radiante si è divisa tale superficie in diverse porzioni per riconoscere le zone della superficie radiante più influenti. I risultati ottenuti mostrano che la presenza di radiatori, finestre o pareti esterne, introducendo elementi di disturbo asimmetrici, forniscono andamenti disuniformi di temperatura e PMV, con l’omogeneità che migliora allontanandosi da tali elementi; impianti a pavimento o soffitto radiante producono risultati decisamente migliori, sia per quanto riguarda i valori assoluti di temperatura e PMV, che nell’omogeneità della relativa distribuzione.

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Mode of access: Internet.

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Mode of access: Internet.

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Mode of access: Internet.

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Bibliography: p. 429-465.