Production of CXC and CC chemokines by human antigen-presenting cells in response to Lassa virus or closely related immunogenic viruses, and in cynomolgus monkeys with lassa fever.

International audienceThe pathogenesis of Lassa fever (LF), a hemorrhagic fever endemic to West Africa, remains unclear. We previously compared Lassa virus (LASV) with its genetically close, but nonpathogenic homolog Mopeia virus (MOPV) and demonstrated that the strong activation of antigen-presenting cells (APC), including type I IFN production, observed in response to MOPV probably plays a crucial role in controlling infection. We show here that human macrophages (MP) produce large amounts of CC and CXC chemokines in response to MOPV infection, whereas dendritic cells (DC) release only moderate amounts of CXC chemokines. However, in the presence of autologous T cells, DCs produced CC and CXC chemokines. Chemokines were produced in response to type I IFN synthesis, as the levels of both mediators were strongly correlated and the neutralization of type I IFN resulted in an inhibition of chemokine production. By contrast, LASV induced only low levels of CXCL-10 and CXCL-11 production. These differences in chemokine production may profoundly affect the generation of virus-specific T-cell responses and may therefore contribute to the difference of pathogenicity between these two viruses. In addition, a recombinant LASV (rLASV) harboring the NP-D389A/G392A mutations, which abolish the inhibition of type I IFN response by nucleoprotein (NP), induced the massive synthesis of CC and CXC chemokines in both DC and MP, confirming the crucial role of arenavirus NP in immunosuppression and pathogenicity. Finally, we confirmed, using PBMC samples and lymph nodes obtained from LASV-infected cynomolgus monkeys, that LF was associated with high levels of CXC chemokine mRNA synthesis, suggesting that the very early synthesis of these mediators may be correlated with a favourable outcome

European survey on laboratory preparedness, response and diagnostic capacity for crimean-congo haemorrhagic fever, 2012

Crimean-Congo haemorrhagic fever (CCHF) is an infectious viral disease that has (re-)emerged in the last decade in south-eastern Europe, and there is a risk for further geographical expansion to western Europe. Here we report the results of a survey covering 28 countries, conducted in 2012 among the member laboratories of the European Network for Diagnostics of 'Imported' Viral Diseases (ENIVD) to assess laboratory preparedness and response capacities for CCHF. The answers of 31 laboratories of the European region regarding CCHF case definition, training necessity, biosafety, quality assurance and diagnostic tests are presented. In addition, we identifi

Modeling Cardiac Stimulation by a Pacemaker, with Accurate Tissue-Electrode Interface

International audienceIn this paper we model a cardiac pacemaker placed in a bath with a cardiac excitable tissue. We take into account electrochemical phenomena observed at the electrodes during pacing by using equivalent circuits, whose parameters are calibrated with respect to bench tests data. The complete model consists of a pacemaker model coupled to a re-scaled cardiac ionic model through these circuits. It is compared with ex-vivo experimental data of stimulation threshold detection. We perform an additional study of the influence of the scaling parameters, that can help matching experimental results

Modeling Cardiac Stimulation by a Pacemaker, with Accurate Tissue-Electrode Interface

International audienceAn implantable pacemaker aims to restore a cardiac beat when the intrisic conduction system fails. It sends energy to the heart in the form of a voltage pulse and it is programmed to deliver enough energy to trigger a cardiac depolarization (which is called capture). We present a 0D model of a cardiac pacemaker with a cardiac tissue. We take into account electrochemical phenomena observed during pacing, like electrode polarization. To validate it, we compare numerical results with ex-vivo experimental data of stimulation threshold detection

From experimental data to 3D realistic simulations: a pacemaker example

International audienceAn implantable pacemaker aims to restore a cardiac beat when the intrisic conduction system fails. It sends energy to the heart in the form of a voltage pulse during a fixed duration and it is programmed to deliver enough energy to trigger a cardiac depolarization.We present results of a 3D model of a cardiac pacemaker with a tissue surrounded by blood. We take into account electrochemical phenomena observed during pacing, like electrode polarization, which is crucial to make realistic simulations. We explain how 2 we use experimental data to feed our model with valid inputs. To validate the model, we will compare numerical results with ex-vivo experimental data of stimulation threshold detection and voltage measurements

WHO collaborative study to assess the suitability of an interim standard for antibodies to Ebola virus

In support of the WHO response to the Ebola crisis, NIBSC is undertaking a project to develop an International Standard for use in the calibration and control of Ebola antibody assays. The availability of International Standards (IS) for antibodies would facilitate the standardization of Ebola serological methods used in epidemiological studies to measure past or present Ebola virus disease and in vaccinology studies to measure antibodies elicited by vaccination in humans. In the absence of such standards, individual laboratories apply their own reference standards which are not harmonized with other laboratories and methods and thus cannot serve to improve the reproducibility between laboratories. Recommendations made by participants attending the Technical Workshop on the Standardisation of Serological and PCR assays for the detection of Ebola virus (NIBSC, UK, 5-6 March 2015), included the urgent prioritization of the development of an interim Ebola standard for serology assays while perusing the longer-term goal of establishing an International Standard according to published WHO guidelines and formally endorsed by the WHO Expert Committee on Biological Standardization (ECBS). This report describes the development and worldwide collaborative study evaluation of a panel of candidate Ebola antibody preparations for the selection of the most appropriate candidate to serve as the interim WHO standard for Ebola antibody assays

European survey on laboratory preparedness, response and diagnostic capacity for crimean-congo haemorrhagic fever, 2012

Crimean-Congo haemorrhagic fever (CCHF) is an infectious viral disease that has (re-)emerged in the last decade in south-eastern Europe, and there is a risk for further geographical expansion to western Europe. Here we report the results of a survey covering 28 countries, conducted in 2012 among the member laboratories of the European Network for Diagnostics of 'Imported' Viral Diseases (ENIVD) to assess laboratory preparedness and response capacities for CCHF. The answers of 31 laboratories of the European region regarding CCHF case definition, training necessity, biosafety, quality assurance and diagnostic tests are presented. In addition, we identified the lack of a Regional Reference Expert Laboratory in or near endemic areas. Moreover, a comprehensive review of the biosafety level suitable to the reality of endemic areas is needed. These issues are challenges that should be addressed by European public health authorities. However, all respondent laboratories have suitable diagnostic capacities for the current situation

Coffin–Lowry syndrome

Coffin–Lowry syndrome (CLS) is a syndromic form of X-linked mental retardation, which is characterized in male patients by psychomotor and growth retardation and various skeletal anomalies. Typical facial changes and specific clinical and radiological signs in the hand are useful aids in the diagnosis. CLS is caused by mutations in the RPS6KA3 gene located at Xp22.2, which encodes RSK2, a growth-factor-regulated protein kinase. RPS6KA3 mutations are extremely heterogeneous and lead to loss of phosphotransferase activity in the RSK2 kinase, most often because of premature termination of translation