767 research outputs found

    Chronic necrotizing pulmonary aspergillosis presenting as bilateral pleural effusion: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Chronic necrotizing pulmonary aspergillosis is an uncommon subacute form of <it>Aspergillus </it>infection. It typically occurs in immunocompromised individuals and in those with underlying lung disease. This interesting case highlights the occurrence of this entity of aspergillosis in an immunocompetent middle-aged woman with atypical radiological findings. To the best of our knowledge this is the first case report of chronic necrotizing pulmonary aspergillosis presenting with pleural effusion.</p> <p>Case presentation</p> <p>Our patient was a 64-year-old Malay woman with a background history of epilepsy but no other comorbidities. She was a lifelong non-smoker. She presented to our facility with a six-month history of productive cough and three episodes of hemoptysis. An initial chest radiograph showed bilateral pleural effusion with bibasal consolidation. Bronchoscopy revealed a white-coated endobronchial tree and bronchoalveolar lavage culture grew <it>Aspergillus niger</it>. A diagnosis of chronic necrotizing pulmonary aspergillosis was made based on the clinical presentation and microbiological results. She responded well to treatment with oral itraconazole.</p> <p>Conclusions</p> <p>The radiological findings in chronic necrotizing pulmonary aspergillosis can be very diverse. This case illustrates that this condition can be a rare cause of bilateral pleural effusion.</p

    What is the valence of a correlated solid? The double life of delta-plutonium

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    Plutonium displays phase transitions with enormous volume differences among its phases and both its Pauli like magnetic susceptibility and resistivity are an order of magnitude larger than those of simple metals. Curium is also highly resistive but its susceptibility is Curie-like at high temperatures and orders antiferromagnetically at low temperatures. The anomalous properties of the late actinides stem from the competition between the itinerancy and localization of its f electrons, which makes the late actinides elemental strongly correlated materials. A central problem in this field is to understand the mechanism by which these materials resolve these conflicting tendencies. In this letter we identify the electronic mechanisms responsible for the anomalous behaviour of late actinides. We revisit the concept of valence using theoretical approach that treats magnetism, Kondo screening, atomic multiplet effects, spin orbit coupling and crystal field splitting on the same footing. Plutonium is found to be in a rare mixed valent state, namely its ground state is a superposition of two distinct valencies. Curium settles in a single valence magnetically ordered state at low temperatures. The f7 atomic configuration of Curium is contrasted with the multiple configuration manifolds present in Plutonium ground state which we characterize by a valence histogram. The balance between the Kondo screening and magnetism is determined by the competition between spin orbit coupling and the strength of atomic multiplets which is in turn regulated by the degree of itinerancy. The approach presented here, highlights the electronic origin of the bonding anomalies in plutonium and can be applied to predict generalized valences and the presence or absence of magnetism in other compounds starting from first principles.Comment: 2 figures, 1 tabl

    A single residue substitution in the receptor-binding domain of H5N1 hemagglutinin is critical for packaging into pseudotyped lentiviral particles

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    © 2012 Tang et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: Serological studies for influenza infection and vaccine response often involve microneutralization and hemagglutination inhibition assays to evaluate neutralizing antibodies against human and avian influenza viruses, including H5N1. We have previously characterized lentiviral particles pseudotyped with H5-HA (H5pp) and validated an H5pp-based assay as a safe alternative for high-throughput serological studies in BSL-2 facilities. Here we show that H5-HAs from different clades do not always give rise to efficient production of H5pp and the underlying mechanisms are addressed. Methodology/Findings: We have carried out mutational analysis to delineate the molecular determinants responsible for efficient packaging of HA from A/Cambodia/40808/2005 (H5Cam) and A/Anhui/1/2005 (H5Anh) into H5pp. Our results demonstrate that a single A134V mutation in the 130-loop of the receptor binding domain is sufficient to render H5Anh the ability to generate H5Anh-pp efficiently, whereas the reverse V134A mutation greatly hampers production of H5Cam-pp. Although protein expression in total cell lysates is similar for H5Anh and H5Cam, cell surface expression of H5Cam is detected at a significantly higher level than that of H5Anh. We further demonstrate by several independent lines of evidence that the behaviour of H5Anh can be explained by a stronger binding to sialic acid receptors implicating residue 134. Conclusions: We have identified a single A134V mutation as the molecular determinant in H5-HA for efficient incorporation into H5pp envelope and delineated the underlying mechanism. The reduced binding to sialic acid receptors as a result of the A134V mutation not only exerts a critical influence in pseudotyping efficiency of H5-HA, but has also an impact at the whole virus level. Because A134V substitution has been reported as a naturally occurring mutation in human host, our results may have implications for the understanding of human host adaptation of avian influenza H5N1 virusesThis work was supported by grants from the Research Fund for the Control of Infectious Diseases of Hong Kong (RFCID#08070972), the Area of Excellence Scheme of the University Grants Committee (grant AoE/M-12/-06 of the Hong Kong Special Administrative Region, China), the French Ministry of Health, and the RESPARI project of the Institut Pasteur International Network

    Anatomical considerations and emerging strategies for reducing new onset conduction disturbances in percutaneous structural heart disease interventions

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    Transcatheter procedures offer an alternative to cardiac surgery in select patients with structural heart disease (SHD). Unfortunately, inadvertent disruption of electrical pathways and subsequent development of new onset conduction disturbances can occur in up to 5–70% of percutaneous interventions, result in pacemaker implantation, and confer a worse prognosis. The physical proximity between the conduction system (atrioventricular node, bundle of His, and bundle branches) and the site of percutaneous repair is increasingly recognized as a key factor influencing new onset conduction disturbance development in procedures located near the conduction system. This review covers the incidence, clinical significance, and mechanisms of new onset conduction disturbances and discusses current and emerging strategies to address this complication in these populations

    Spinal involvement in mucopolysaccharidosis IVA (Morquio-Brailsford or Morquio A syndrome): presentation, diagnosis and management.

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    Mucopolysaccharidosis IVA (MPS IVA), also known as Morquio-Brailsford or Morquio A syndrome, is a lysosomal storage disorder caused by a deficiency of the enzyme N-acetyl-galactosamine-6-sulphate sulphatase (GALNS). MPS IVA is multisystemic but manifests primarily as a progressive skeletal dysplasia. Spinal involvement is a major cause of morbidity and mortality in MPS IVA. Early diagnosis and timely treatment of problems involving the spine are critical in preventing or arresting neurological deterioration and loss of function. This review details the spinal manifestations of MPS IVA and describes the tools used to diagnose and monitor spinal involvement. The relative utility of radiography, computed tomography (CT) and magnetic resonance imaging (MRI) for the evaluation of cervical spine instability, stenosis, and cord compression is discussed. Surgical interventions, anaesthetic considerations, and the use of neurophysiological monitoring during procedures performed under general anaesthesia are reviewed. Recommendations for regular radiological imaging and neurologic assessments are presented, and the need for a more standardized approach for evaluating and managing spinal involvement in MPS IVA is addressed
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