2,049 research outputs found

    Inferring Influenza Infection Attack Rate from Seroprevalence Data

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    Differences between normal and demineralized dentine pretreated with silver fluoride and potassium iodide after an in vitro challenge by Streptococcus mutans

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    The document attached has been archived with permission from the Australian Dental Association (8 March 2008). An external link to the publisher’s copy is included.Background: The application of diamine silver fluoride (Ag(NH3)2F) and potassium iodide (KI) to demineralized dentine has been shown to inhibit the growth of Streptococcus mutans. The purpose of this study was to observe the differences between demineralized and non-demineralized dentine treated with AgF/KI. Methods: Thirty-five dentine discs were bonded to the bases of 5mL polycarbonate screw top vials which were filled with nutrient medium, sterilized and placed into the overflow from a continuous culture of S. mutans. Samples were divided as follows: 10 samples of demineralized dentine; 10 samples of demineralized dentine treated with AgF/KI; 5 samples of non-demineralized dentine; and 10 samples of non-demineralized dentine treated with AgF/KI. Following two weeks connected to the Chemostat, an electron probe microanalysis (EPMA) of percentage weights and penetration depths of calcium, phosphorous silver and fluoride was conducted. Bacterial growth was monitored by taking optical density readings of the growth medium in each vial and outer surfaces of the specimens were examined by scanning electron microscopy (SEM). Results: AgF/KI treatment of demineralized and non-demineralized dentine prevented biofilm formation and reduced further demineralization by S. mutans. AgF/KI treatment of demineralized dentine was more effective in reducing dentine breakdown and the growth of S. mutans. Significantly higher levels of silver and fluoride were deposited within demineralized dentine. Conclusions: A topical treatment with AgF/KI on dentine reduced in vitro caries development and inhibited surface biofilm formation. Reduction of in vitro caries development and viability of S. mutans was more pronounced on the dentine samples that had been demineralized prior to the application of AgF/KI.GM Knight, JM McIntyre, GG Craig, Mulyani, PS Zilm and NJ Gull

    Spinal or general anaesthesia for surgical repair of hip fracture and subsequent risk of mortality and morbidity: a database analysis using propensity score‐matching

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    Around 76,000 people fracture their hip annually in the UK at a considerable personal, social and financial cost. Despite longstanding debate, the optimal mode of anaesthesia (general or spinal) remains unclear. Our aim was to assess whether there is a significant difference in mortality and morbidity between patients undergoing spinal anaesthesia compared with general anaesthesia during hip fracture surgery. A secondary analysis examined whether a difference exists in mortality for patients with pre‐existing cardiovascular disease or chronic obstructive pulmonary disease. This was a clinical database analysis of patients treated for hip fracture in Nottingham, UK between 2004 and 2015. Propensity score‐matching was used to generate matched pairs of patients, one of whom underwent each mode of anaesthesia. Data were analysed using conditional logistic regression, with 7164 patients successfully matched. There was no difference in 30‐ or 90‐day mortality in patients who had spinal rather than general anaesthesia (OR [95%CI] 0.97 [0.8–1.15]; p = 0.764 and 0.93 [0.82–1.05]; p = 0.247 respectively). Patients who had a spinal anaesthetic had a lower‐risk of blood transfusion (OR [95%CI] 0.84 [0.75–0.94]; p = 0.003) and urinary tract infection (OR [95%CI] 0.72 [0.61–0.84]; p [less than] 0.001), but were more likely to develop a chest infection (OR [95%CI] 1.23 [1.07–1.42]; p = 0.004), deep vein thrombosis (OR [95%CI] 2.18 [1.07–4.45]; p = 0.032) or pulmonary embolism (OR [95%CI] 2.23 [1.16–4.29]; p = 0.016). The mode of anaesthesia for hip fracture surgery resulted in no significant difference in mortality, but there was a significant difference in several measures of postoperative morbidity

    Role of polymorphisms of the inflammatory response genes and DC-SIGNR in genetic susceptibility to SARS and other infections.

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    Research Fund for the Control of Infectious Diseases: Research Dissemination Reports (Series 2)1. A genetic risk-association study involving more than 1200 subjects showed individuals homozygous for L-SIGN tandem repeats are less susceptible to SARS infection. 2. This was supported by in vitro binding studies that demonstrated homozygous L-SIGN, compared to heterozygous, had higher binding capacity for SARS coronavirus (SARS-CoV), with higher proteasome-dependent viral degradation. In contrast, homozygous L-SIGN demonstrated lower binding capacity for HIV1-gp120.3. Genetic-association studies for single nucleotide polymorphisms of the inflammatory response genes, namely TNF-alpha, INF-alpha, INF-beta, INF-gamma, IL1-alpha, IL1-beta, IL-4, IL-6 and iNOS, failed to show a significant association with SARS clinical outcomes or susceptibility.published_or_final_versio

    Extrapontine myelinolysis presenting as acute parkinsonism

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    BACKGROUND: Extrapontine myelinolysis presenting with extra pyramidal features suggestive of parkinsonism may be a challenging clinical syndrome. Clinicians should maintain their vigilance while correcting electrolyte imbalances, especially with associated co-morbidity. CASE PRESENTATION: A 41-year-old woman presented with acute parkinsonism like features while on a holiday. This followed slow correction of hyponatraemia after repeated vomiting. MRI changes were suggestive of Extrapontine myelinolysis(EPM). This case is at variance with four previous cases reported in the medical literature in that the patient made a full clinical recovery and the MR changes resolved with symptomatic support alone. CONCLUSION: Extrapontine myelinolysis could make a complete recovery with symptomatic support alone. During hyponatraemia correction, rapid osmotic shifts of fluid that cause hypernatremia, causes myelinolysis rather than absolute serum sodium level. Even gradual correction of hyponatraemia can produce myelinolysis, especially with pre-existing malnourishment, alcoholism, drug misuse, Addison's disease and immuno-suppression. Pallidial sparing is typical of EPM in MRI scans

    Monitoring iron chelation effect in hearts of thalassaemia patients with improved sensitivity using reduced transverse relaxation rate (RR2)

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    Posters - Myocardial Viability: Human Models: No. 3660Accurate MRI characterization of myocardial iron is needed to improve the diagnosis and management of thalassaemia patients with transfusional iron overload. This study aimed to demonstrate that a new transverse relaxation index, the reduced R2 (RR2) that is estimated from non-monoexponential multi-echo CPMG signal decay and sensitive to ferritin iron, could detect the myocardial iron changes immediately following 1-week iron chelation suspension in thalassaemia patients at 3T.postprin

    Influence of metals and metalloids on the composition and fluorescence quenching of the extracellular polymeric substances produced by the polymorphic fungus <i>Aureobasidium pullulans</i>

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    Aureobasidium pullulansis a ubiquitous and widely distributed fungus in the environment, and exhibits substantial tolerance against toxic metals. However, the interactions between metals and metalloids with the copious extracellular polymeric substances (EPS) produced byA. pullulansand possible relationships to tolerance are not well understood. In this study, it was found that mercury (Hg) and selenium (Se), as selenite, not only significantly inhibited growth ofA. pullulansbut also affected the composition of produced EPS. Lead (Pb) showed little influence on EPS yield or composition. The interactions of EPS fromA. pullulanswith the tested metals and metalloids depended on the specific element and their concentration. Fluorescence intensity measurements of the EPS showed that the presence of metal(loid)s stimulated the production of extracellular tryptophan-like and aromatic protein-like substances. Examination of fluorescence quenching and calculation of binding constants revealed that the fluorescence quenching process for Hg; arsenic (As), as arsenite; and Pb to EPS were mainly governed by static quenching which resulted in the formation of a stable non-fluorescent complexes between the EPS and metal(loid)s. Se showed no significant interaction with the EPS according to fluorescence quenching. These results provide further understanding of the interactions between metals and metalloids and EPS produced by fungi and their contribution to metal(loid) tolerance

    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

    A detailed longitudinal study of infection attack rates among healthy adults in Hong Kong during the epidemic of the human swine influenza A/H1N1 virus in 2009

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    Conference Theme: Translating Health Research into Policy and Practice for Health of the PopulationPoster Presentations: Emerging / Infectious Diseases: abstract no. P109-Ab0091published_or_final_versio
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