109 research outputs found

    Cisternal Organization of the Endoplasmic Reticulum during Mitosis

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    The endoplasmic reticulum (ER) of animal cells is a single, dynamic, and continuous membrane network of interconnected cisternae and tubules spread out throughout the cytosol in direct contact with the nuclear envelope. During mitosis, the nuclear envelope undergoes a major rearrangement, as it rapidly partitions its membrane-bound contents into the ER. It is therefore of great interest to determine whether any major transformation in the architecture of the ER also occurs during cell division. We present structural evidence, from rapid, live-cell, three-dimensional imaging with confirmation from high-resolution electron microscopy tomography of samples preserved by high-pressure freezing and freeze substitution, unambiguously showing that from prometaphase to telophase of mammalian cells, most of the ER is organized as extended cisternae, with a very small fraction remaining organized as tubules. In contrast, during interphase, the ER displays the familiar reticular network of convolved cisternae linked to tubules

    Sublingual Immunization with a Live Attenuated Influenza A Virus Lacking the Nonstructural Protein 1 Induces Broad Protective Immunity in Mice

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    The nonstructural protein 1 (NS1) of influenza A virus (IAV) enables the virus to disarm the host cell type 1 IFN defense system. Mutation or deletion of the NS1 gene leads to attenuation of the virus and enhances host antiviral response making such live-attenuated influenza viruses attractive vaccine candidates. Sublingual (SL) immunization with live influenza virus has been found to be safe and effective for inducing protective immune responses in mucosal and systemic compartments. Here we demonstrate that SL immunization with NS1 deleted IAV (DeltaNS1 H1N1 or DeltaNS1 H5N1) induced protection against challenge with homologous as well as heterosubtypic influenza viruses. Protection was comparable with that induced by intranasal (IN) immunization and was associated with high levels of virus-specific antibodies (Abs). SL immunization with DeltaNS1 virus induced broad Ab responses in mucosal and systemic compartments and stimulated immune cells in mucosa-associated and systemic lymphoid organs. Thus, SL immunization with DeltaNS1 offers a novel potential vaccination strategy for the control of influenza outbreaks including pandemics

    Cost-effectiveness of percutaneous coronary intervention with cobalt-chromium everolimus eluting stents versus bare metal stents: Results from a patient level meta-analysis of randomized trials

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    Background: Second-generation drug eluting stents (DES) may reduce costs and improve clinical outcomes compared to first-generation DES with improved cost-effectiveness when compared to bare metal stents (BMS). We aimed to conduct an economic evaluation of a cobalt-chromium everolimus eluting stent (Co-Cr EES) compared with BMS in percutaneous coronary intervention (PCI). Objective: To conduct a cost-effectiveness analysis (CEA) of a cobalt-chromium everolimus eluting stent (Co-Cr EES) versus BMS in PCI. Methods: A Markov state transition model with a 2-year time horizon was applied from a US Medicare setting with patients undergoing PCI with Co-Cr EES or BMS. Baseline characteristics, treatment effects, and safety measures were taken from a patient level meta-analysis of 5 RCTs (n=4,896). The base-case analysis evaluated stent-related outcomes; a secondary analysis considered the broader set of outcomes reported in the meta-analysis. Results: The base-case and secondary analyses reported an additional 0.018 and 0.013 quality-adjusted life years (QALYs) and cost savings of 236and236 and 288, respectively with Co-Cr EES versus BMS. Results were robust to sensitivity analyses and were most sensitive to the price of clopidogrel. In the probabilistic sensitivity analysis, Co-Cr EES was associated with a greater than 99% chance of being cost savin

    Human papillomavirus vaccine introduction in low-income and middle-income countries: guidance on the use of cost-effectiveness models

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    BACKGROUND: The World Health Organization (WHO) recommends that the cost effectiveness of introducing human papillomavirus (HPV) vaccination is considered before such a strategy is implemented. However, developing countries often lack the technical capacity to perform and interpret results of economic appraisals of vaccines. To provide information about the feasibility of using such models in a developing country setting, we evaluated models of HPV vaccination in terms of their capacity, requirements, limitations and comparability. METHODS: A literature review identified six HPV vaccination models suitable for low-income and middle-income country use and representative of the literature in terms of provenance and model structure. Each model was adapted by its developers using standardised data sets representative of two hypothetical developing countries (a low-income country with no screening and a middle-income country with limited screening). Model predictions before and after vaccination of adolescent girls were compared in terms of HPV prevalence and cervical cancer incidence, as was the incremental cost-effectiveness ratio of vaccination under different scenarios. RESULTS: None of the models perfectly reproduced the standardised data set provided to the model developers. However, they agreed that large decreases in type 16/18 HPV prevalence and cervical cancer incidence are likely to occur following vaccination. Apart from the Thai model (in which vaccine and non-vaccine HPV types were combined), vaccine-type HPV prevalence dropped by 75% to 100%, and vaccine-type cervical cancer incidence dropped by 80% to 100% across the models (averaging over age groups). The most influential factors affecting cost effectiveness were the discount rate, duration of vaccine protection, vaccine price and HPV prevalence. Demographic change, access to treatment and data resolution were found to be key issues to consider for models in developing countries. CONCLUSIONS: The results indicated the usefulness of considering results from several models and sets of modelling assumptions in decision making. Modelling groups were prepared to share their models and expertise to work with stakeholders in developing countries. Please see related article: http://www.biomedcentral.com/1741-7007/9/55

    Estimating the long-term impact of a prophylactic human papillomavirus 16/18 vaccine on the burden of cervical cancer in the UK

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    To predict the public health impact on cervical disease by introducing human papillomavirus (HPV) vaccination in the United Kingdom, we developed a mathematical model that can be used to reflect the impact of vaccination in different countries with existing screening programmes. Its use is discussed in the context of the United Kingdom. The model was calibrated with published data. The impact of vaccination on cervical cancer and deaths, precancerous lesions and screening outcomes were estimated for a vaccinated cohort of 12-year-old girls, among which it is estimated that there would be a reduction of 66% in the prevalence of high-grade precancerous lesions and a 76% reduction in cervical cancer deaths. Estimates for various other measures of the population effects of vaccination are also presented. We concluded that it is feasible to forecast the potential effects of HPV vaccination in the context of an existing national screening programme. Results suggest a sizable reduction in the incidence of cervical cancer and related deaths. Areas for future research include investigation of the beneficial effects of HPV vaccination on infection transmission and epidemic dynamics, as well as HPV-related neoplasms in other sites

    Rotavirus NSP1 Inhibits NFκB Activation by Inducing Proteasome-Dependent Degradation of β-TrCP: A Novel Mechanism of IFN Antagonism

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    Mechanisms by which viruses counter innate host defense responses generally involve inhibition of one or more components of the interferon (IFN) system. Multiple steps in the induction and amplification of IFN signaling are targeted for inhibition by viral proteins, and many of the IFN antagonists have direct or indirect effects on activation of latent cytoplasmic transcription factors. Rotavirus nonstructural protein NSP1 blocks transcription of type I IFNα/β by inducing proteasome-dependent degradation of IFN-regulatory factors 3 (IRF3), IRF5, and IRF7. In this study, we show that rotavirus NSP1 also inhibits activation of NFκB and does so by a novel mechanism. Proteasome-mediated degradation of inhibitor of κB (IκBα) is required for NFκB activation. Phosphorylated IκBα is a substrate for polyubiquitination by a multisubunit E3 ubiquitin ligase complex, Skp1/Cul1/F-box, in which the F-box substrate recognition protein is β-transducin repeat containing protein (β-TrCP). The data presented show that phosphorylated IκBα is stable in rotavirus-infected cells because infection induces proteasome-dependent degradation of β-TrCP. NSP1 expressed in isolation in transiently transfected cells is sufficient to induce this effect. Targeted degradation of an F-box protein of an E3 ligase complex with a prominent role in modulation of innate immune signaling and cell proliferation pathways is a unique mechanism of IFN antagonism and defines a second strategy of immune evasion used by rotaviruses

    A Recombinant Influenza A Virus Expressing Domain III of West Nile Virus Induces Protective Immune Responses against Influenza and West Nile Virus

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    West Nile virus (WNV) continues to circulate in the USA and forms a threat to the rest of the Western hemisphere. Since methods for the treatment of WNV infections are not available, there is a need for the development of safe and effective vaccines. Here, we describe the construction of a recombinant influenza virus expressing domain III of the WNV glycoprotein E (Flu-NA-DIII) and its evaluation as a WNV vaccine candidate in a mouse model. FLU-NA-DIII-vaccinated mice were protected from severe body weight loss and mortality caused by WNV infection, whereas control mice succumbed to the infection. In addition, it was shown that one subcutaneous immunization with 105 TCID50 Flu-NA-DIII provided 100% protection against challenge. Adoptive transfer experiments demonstrated that protection was mediated by antibodies and CD4+T cells. Furthermore, mice vaccinated with FLU-NA-DIII developed protective influenza virus-specific antibody titers. It was concluded that this vector system might be an attractive platform for the development of bivalent WNV-influenza vaccines
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