79 research outputs found

    A hepatitis C avidity test for determining recent and past infections in both plasma and dried blood spots

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    DBS testing has been used successfully to detect HCV antibody positive individuals. Determining how long someone has been infected is important for surveillance initiatives. Antibody avidity is a method that can be used to calculate recency of infection. A HCV avidity assay was evaluated for both plasma and DBS. Study design: To measure antibody avidity a commercial HCV ELISA was modified using 7 M urea. The plasma samples were split into: group 1 (recently infected N = 19), group 2 (chronic carrier N = 300) and group 3 (resolved infection N = 82). Mock DBS made from group 1 (N = 12), group 2 (N = 50), group 3 (N = 25) and two seroconverter panels were evaluated. 133 DBS taken from patients known to have a resolved infection or be a chronic carrier were also tested. The avidity assay cut-off was set at AI ≤ 30 for a recent infection. Using sequential samples the assay could detect a recent infection in the first 4–5 months from the point of infection. Most of the false positive results (AI < 30 among cases known not to have had recent infection) were detected among known resolved infections, in both the plasma and DBS; as a result, a testing algorithm has been designed incorporating both PCR and two dilution factors. The sensitivity and specificity of the assay on plasma was 100% and 99.3%, respectively, while DBS had 100% sensitivity and 98.3% specificity. The HCV avidity assay can be used to distinguish between chronic and recent infection using either plasma or DBS as the sample type

    During the summer 2009 outbreak of "swine flu" in Scotland what respiratory pathogens were diagnosed as H1N1/2009?

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    <p>Abstract</p> <p>Background</p> <p>During the April-July 2009 outbreak of H1N1/2009 in scotland the West of Scotland Specialist Virology Centre (WoSSVC) in Glasgow tested > 16 000 clinical samples for H1N1/2009. Most were from patients clinically diagnosed with H1N1/2009. Out of these, 9% were positive. This study sought to determine what respiratory pathogens were misdiagnosed as cases of H1N1/2009 during this time.</p> <p>Methods</p> <p>We examined the results from 3247 samples which were sent to the laboratory during April-July 2009. All were from patients clinically diagnosed as having H1N1/2009 (based on accepted criteria) and all were given a full respiratory screen using real time reverse transcriptase polymerase chain reaction (rtRT-PCR) assays.</p> <p>Results</p> <p>In total, respiratory pathogens were detected in 27.9% (95% confidence interval, 26.3-29.5%) of the samples submitted. Numerous pathogens were detected, the most common of which were rhinovirus (8.9% (95% confidence interval, 7.9-9.9%)), parainfluenza 1 (1.9% (95% confidence interval, 1.4-2.4%)) and 3 (4.1% (95% confidence interval, 3.3-4.9%)), and adenovirus ((3.5% (95% confidence interval, 2.9-4.2%)).</p> <p>Conclusions</p> <p>This study highlights the problems of using a clinical algorithm to detect H1N1/2009. Clinicians frequently misdiagnosed common respiratory pathogens as H1N1/2009 during the spring/summer outbreak in Scotland. Many undesirable consequences would have resulted, relating to treatment, infection control, and public health surveillance.</p

    Reduction of Natural Killer but Not Effector CD8 T Lymphoyctes in Three Consecutive Cases of Severe/Lethal H1N1/09 Influenza A Virus Infection

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    Background: The cause of severe disease in some patients infected with pandemic influenza A virus is unclear. Methodology/Principal Findings: We present the cellular immunology profile in the blood, and detailed clinical (and postmortem) findings of three patients with rapidly progressive infection, including a pregnant patient who died. The striking finding is of reduction in natural killer (NK) cells but preservation of activated effector CD8 T lymphocytes; with viraemia in the patient who had no NK cells. Comparison with control groups suggests that the reduction of NK cells is unique to these severely ill patients. Conclusion/Significance: Our report shows markedly reduced NK cells in the three patients that we sampled and raises the hypothesis that NK may have a more significant role than T lymphocytes in controlling viral burden when the host is confronted with a new influenza A virus subtype

    The Neurotoxicity of DOPAL: Behavioral and Stereological Evidence for Its Role in Parkinson Disease Pathogenesis

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    BACKGROUND: The etiology of Parkinson disease (PD) has yet to be fully elucidated. We examined the consequences of injections of 3,4-dihydroxyphenylacetaldehyde (DOPAL), a toxic metabolite of dopamine, into the substantia nigra of rats on motor behavior and neuronal survival. METHODS/PRINCIPAL FINDINGS: A total of 800 nl/rat of DOPAL (1 µg/200 nl) was injected stereotaxically into the substantia nigra over three sites while control animals received similar injections of phosphate buffered saline. Rotational behavior of these rats was analyzed, optical density of striatal tyrosine hydroxylase was calculated, and unbiased stereological counts of the substantia nigra were made. The rats showed significant rotational asymmetry ipsilateral to the lesion, supporting disruption of dopaminergic nigrostriatal projections. Such disruption was verified since the density of striatal tyrosine hydroxylase decreased significantly (p<0.001) on the side ipsilateral to the DOPAL injections when compared to the non-injected side. Stereological counts of neurons stained for Nissl in pars compacta of the substantia nigra significantly decreased (p<0.001) from control values, while counts of those in pars reticulata were unchanged after DOPAL injections. Counts of neurons immunostained for tyrosine hydroxylase also showed a significant (p=0.032) loss of dopaminergic neurons. In spite of significant loss of dopaminergic neurons, DOPAL injections did not induce significant glial reaction in the substantia nigra. CONCLUSIONS: The present study provides the first in vivo quantification of substantia nigra pars compacta neuronal loss after injection of the endogenous toxin DOPAL. The results demonstrate that injections of DOPAL selectively kills SN DA neurons, suggests loss of striatal DA terminals, spares non-dopaminergic neurons of the pars reticulata, and triggers a behavioral phenotype (rotational asymmetry) consistent with other PD animal models. This study supports the "catecholaldehyde hypothesis" as an important link for the etiology of sporadic PD

    Luminescent Tris(8-hydroxyquinolates) of Bismuth(III)

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    Luminescent homoleptic bismuth(III) complexes have been synthesized by adding several functionalized 8-hydroxyquinolate ligands to bismuth(III) chloride in a 3:1 mole ratio in either ethanol or tetrahydrofuran (THF) solvent. These complexes have been characterized by single-crystal X-ray diffraction (XRD) analysis, UV-vis spectroscopy, fluorescence spectroscopy, and density functional theory (DFT) calculations to determine their structures and photophysical properties. Reversible dimerization of the mononuclear tris(hydroxyquinolate) complexes was observed in solution and quantified using UV-vis spectroscopy. The fluorescence spectra show a blue shift for the monomer compared with homoleptic aluminum(III) hydroxyquinolate compounds. Four dimeric compounds and one monomeric isomer were characterized structurally. The bismuth(III) centers in the dimers are bridged by two oxygen atoms from the substituted hydroxyquinolate ligands. The more sterically hindered quinolate complex, tris(2-(diethoxymethyl)-8-quinolinato)bismuth, crystallizes as a monomer. The complexes all exhibit low-lying absorption and emission spectral features attributable to transitions between the HOMO (π orbital localized on the quinolate phenoxide ring) and LUMO (π* orbital localized on the quinolate pyridyl ring). Excitation and emission spectra show a concentration dependence in solution that suggests that a monomer-dimer equilibrium occurs. Electronic structure DFT calculations support trends seen in the experimental results with a HOMO-LUMO gap of 2.156 eV calculated for the monomer that is significantly larger than those for the dimers (1.772 and 1.915 eV). The close face to face approach of two quinolate rings in the dimer destabilizes the uppermost occupied quinolate π orbitals, which reduces the HOMO-LUMO gap and results in longer wavelength absorption and emission spectral features than in the monomer form

    Influenza in old age

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