284 research outputs found

    Treating and Preventing Influenza in Aged Care Facilities: A Cluster Randomised Controlled Trial

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    PMCID: PMC3474842This 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

    Influenza and respiratory syncytial virus infections in British Hajj pilgrims

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    Viral respiratory infections including influenza and respiratory syncytial virus (RSV) have been reported during the Hajj among international pilgrims. To help establish the burden of these infections at the Hajj, we set up a study to confirm these diagnoses in symptomatic British pilgrims who attended the 2005 Hajj. UK pilgrims with symptoms of upper respiratory tract infection (URTI) were invited to participate; after taking medical history, nasal swabs were collected for point-of-care testing (PoCT) of influenza and for subsequent PCR analysis for influenza and RSV. Of the 205 patients recruited, 37 (18%) were positive for either influenza or RSV. Influenza A (H3) accounted for 54% (20/37) of the virus-positive samples, followed by RSV 24% (9/37), influenza B 19% (7/37), and influenza A (H1) 3% (1/37). Of the influenza-positive cases, 29% (8/28) had recently had a flu immunisation. Influenza was more common in those who gave a history of contact with a pilgrim with a respiratory illness than those who did not (17 versus 9%). The overall rate of RSV was 4% (9/202). This study confirms that influenza and RSV cause acute respiratory infections in British Hajj pilgrims. Continuing surveillance and a programme of interventions to contain the spread of infection are needed at the Hajj, particularly when the world is preparing for an influenza pandemic

    Forces During Bacteriophage DNA Packaging and Ejection

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    The conjunction of insights from structural biology, solution biochemistry, genetics and single molecule biophysics has provided a renewed impetus for the construction of quantitative models of biological processes. One area that has been a beneficiary of these experimental techniques is the study of viruses. In this paper we describe how the insights obtained from such experiments can be utilized to construct physical models of processes in the viral life cycle. We focus on dsDNA bacteriophages and show that the bending elasticity of DNA and its electrostatics in solution can be combined to determine the forces experienced during packaging and ejection of the viral genome. Furthermore, we quantitatively analyze the effect of fluid viscosity and capsid expansion on the forces experienced during packaging. Finally, we present a model for DNA ejection from bacteriophages based on the hypothesis that the energy stored in the tightly packed genome within the capsid leads to its forceful ejection. The predictions of our model can be tested through experiments in vitro where DNA ejection is inhibited by the application of external osmotic pressure

    Equation of state for polymer liquid crystals: theory and experiment

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    The first part of this paper develops a theory for the free energy of lyotropic polymer nematic liquid crystals. We use a continuum model with macroscopic elastic moduli for a polymer nematic phase. By evaluating the partition function, considering only harmonic fluctuations, we derive an expression for the free energy of the system. We find that the configurational entropic part of the free energy enhances the effective repulsive interactions between the chains. This configurational contribution goes as the fourth root of the direct interactions. Enhancement originates from the coupling between bending fluctuations and the compressibility of the nematic array normal to the average director. In the second part of the paper we use osmotic stress to measure the equation of state for DNA liquid crystals in 0.1M to 1M NaCl solutions. These measurements cover 5 orders of magnitude in DNA osmotic pressure. At high osmotic pressures the equation of state, dominated by exponentially decaying hydration repulsion, is independent of the ionic strength. At lower pressures the equation of state is dominated by fluctuation enhanced electrostatic double layer repulsion. The measured equation of state for DNA fits well with our theory for all salt concentrations. We are able to extract the strength of the direct electrostatic double layer repulsion. This is a new and alternative way of measuring effective charge densities along semiflexible polyelectrolytes.Comment: text + 5 figures. Submitted to PR

    Causes and clinical features of childhood encephalitis: a multicenter, prospective cohort study

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    BACKGROUND:We aimed to determine the contemporary causes, clinical features, and short-term outcome of encephalitis in Australian children. METHODS:We prospectively identified children (≤14 years of age) admitted with suspected encephalitis at 5 major pediatric hospitals nationally between May 2013 and December 2016 using the Paediatric Active Enhanced Disease Surveillance (PAEDS) Network. A multidisciplinary expert panel reviewed cases and categorized them using published definitions. Confirmed encephalitis cases were categorized into etiologic subgroups. RESULTS:From 526 cases of suspected encephalitis, 287 children met criteria for confirmed encephalitis: 57% (95% confidence interval [CI], 52%-63%) had infectious causes, 10% enterovirus, 10% parechovirus, 8% bacterial meningoencephalitis, 6% influenza, 6% herpes simplex virus (HSV), and 6% Mycoplasma pneumoniae; 25% (95% CI, 20%-30%) had immune-mediated encephalitis, 18% acute disseminated encephalomyelitis, and 6% anti-N-methyl-d-aspartate receptor encephalitis; and 17% (95% CI, 13%-21%) had an unknown cause. Infectious encephalitis occurred in younger children (median age, 1.7 years [interquartile range {IQR}, 0.1-6.9]) compared with immune-mediated encephalitis (median age, 7.6 years [IQR, 4.6-12.4]). Varicella zoster virus encephalitis was infrequent following high vaccination coverage since 2007. Thirteen children (5%) died: 11 with infectious causes (2 influenza; 2 human herpesvirus 6; 2 group B Streptococcus; 2 Streptococcus pneumoniae; 1 HSV; 1 parechovirus; 1 enterovirus) and 2 with no cause identified. Twenty-seven percent (95% CI, 21%-31%) of children showed moderate to severe neurological sequelae at discharge. CONCLUSIONS:Epidemic viral infections predominated as causes of childhood encephalitis in Australia. The leading causes include vaccine-preventable diseases. There were significant differences in age, clinical features, and outcome among leading causes. Mortality or short-term neurological morbidity occurred in one-third of cases.Philip N Britton, Russell C Dale, Christopher C Blyth, Julia E Clark, Nigel Crawford, Helen Marshall ... et al

    Comparative Economic Evaluation of Haemophilus influenzae Type b Vaccination in Belarus and Uzbekistan

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    BACKGROUND: Hib vaccine has gradually been introduced into more and more countries during the past two decades, partly due to GAVI Alliance support to low-income countries. However, since Hib disease burden is difficult to establish in settings with limited diagnostic capacities and since the vaccine continues to be relatively expensive, some Governments remain doubtful about its value leading to concerns about financial sustainability. Similarly, several middle-income countries have not introduced the vaccine. The aim of this study is to estimate and compare the cost-effectiveness of Hib vaccination in a country relying on self-financing (Belarus) and a country eligible for GAVI Alliance support (Uzbekistan). METHODS AND FINDINGS: A decision analytic model was used to estimate morbidity and mortality from Hib meningitis, Hib pneumonia and other types of Hib disease with and without the vaccine. Treatment costs were attached to each disease event. Data on disease incidence, case fatality ratios and costs were primarily determined from national sources. For the Belarus 2009 birth cohort, Hib vaccine is estimated to prevent 467 invasive disease cases, 4 cases of meningitis sequelae, and 3 deaths, while in Uzbekistan 3,069 invasive cases, 34 sequelae cases and 341 deaths are prevented. Estimated costs per discounted DALY averted are US9,323inBelarusandUS 9,323 in Belarus and US 267 in Uzbekistan. CONCLUSION: The primary reason why the cost-effectiveness values are more favourable in Uzbekistan than in Belarus is that relatively more deaths are averted in Uzbekistan due to higher baseline mortality burden. Two other explanations are that the vaccine price is lower in Uzbekistan and that Uzbekistan uses a three dose schedule compared to four doses in Belarus. However, when seen in the context of the relative ability to pay for public health, the vaccine can be considered cost-effective in both countries

    Broad targeting of resistance to apoptosis in cancer

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    Apoptosis or programmed cell death is natural way of removing aged cells from the body. Most of the anti-cancer therapies trigger apoptosis induction and related cell death networks to eliminate malignant cells. However, in cancer, de-regulated apoptotic signaling, particularly the activation of an anti-apoptotic systems, allows cancer cells to escape this program leading to uncontrolled proliferation resulting in tumor survival, therapeutic resistance and recurrence of cancer. This resistance is a complicated phenomenon that emanates from the interactions of various molecules and signaling pathways. In this comprehensive review we discuss the various factors contributing to apoptosis resistance in cancers. The key resistance targets that are discussed include (1) Bcl-2 and Mcl-1 proteins; (2) autophagy processes; (3) necrosis and necroptosis; (4) heat shock protein signaling; (5) the proteasome pathway; (6) epigenetic mechanisms; and (7) aberrant nuclear export signaling. The shortcomings of current therapeutic modalities are highlighted and a broad spectrum strategy using approaches including (a) gossypol; (b) epigallocatechin-3-gallate; (c) UMI-77 (d) triptolide and (e) selinexor that can be used to overcome cell death resistance is presented. This review provides a roadmap for the design of successful anti-cancer strategies that overcome resistance to apoptosis for better therapeutic outcome in patients with cancer

    The RNA helicase RHAU (DHX36) unwinds a G4-quadruplex in human telomerase RNA and promotes the formation of the P1 helix template boundary

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    Human telomerase RNA (hTR) contains several guanine tracts at its 5′-end that can form a G4-quadruplex structure. Previous evidence suggests that a G4-quadruplex within this region disrupts the formation of an important structure within hTR known as the P1 helix, a critical element in defining the template boundary for reverse transcription. RNA associated with AU-rich element (RHAU) is an RNA helicase that has specificity for DNA and RNA G4-quadruplexes. Two recent studies identify a specific interaction between hTR and RHAU. Herein, we confirm this interaction and identify the minimally interacting RNA fragments. We demonstrate the existence of multiple quadruplex structures within the 5′ region of hTR and find that these regions parallel the minimal sequences capable of RHAU interaction. We confirm the importance of the RHAU-specific motif in the interaction with hTR and demonstrate that the helicase activity of RHAU is sufficient to unwind the quadruplex and promote an interaction with 25 internal nucleotides to form a stable P1 helix. Furthermore, we have found that a 5′-terminal quadruplex persists following P1 helix formation that retains affinity for RHAU. Finally, we have investigated the functional implications of this interaction and demonstrated a reduction in average telomere length following RHAU knockdown by small interfering RNA (siRNA)

    Dynamic modeling of the reactive twin-screw co-rotating extrusion process: experimental validation by using inlet glass fibers injection response and application to polymers degassing

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    International audienceIn this paper is described an original dynamic model of a reactive co-rotating twinscrew extrusion (TSE) process operated by the Rhodia company for the Nylon-66 degassing finishing step. In order to validate the model, dynamic experiments have been performed on a small-scale pilot plant. These experiments consist in a temporary injection of glass fibers at the inlet of the extruder after it has reached a given operating point. The outlet glass fibers mass fraction time variation is then measured. This experiment does not lead to the RTD measurement. As a matter of fact, due to the high quantity of glass fibers that is introduced, the behavior of the flow through the extruder is perturbed so that the glass fibers cannot be considered as an inert tracer. The dynamic model that we have published elsewhere (Choulak et al., Ind. Eng. Chem. Res., 2004, 43(23), 7373-7382) is adapted to take into account this nonlinear behavior of the extruder with respect to the glass fibers injection and is favorably compared to experimental results. The description of the degassing operation is also included in the model. The model allows simulations of the complete dynamic behavior of the process. When the steady state is reached, the good position of the degassing vent with respect to the partially and fully filled zones positions can also be checked, thus illustrating the way the model can be used for design purposes
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