744 research outputs found
Lymphoplasmacytic Sclerosing Pancreatitis and Retroperitoneal Fibrosis
Although cases of lymphoplasmacytic sclerosing pancreatitis (LSP) associated with idiopathic retroperitoneal fibrosis have been reported, the association is rare. We describe a 74-year-old man who presented with obstructive jaundice and weight loss. Nineteen months earlier, he had been diagnosed with idiopathic retroperitoneal fibrosis and treated with bilateral ureteric stents. Initial investigations were suggestive of a diagnosis of LSP, however, a malignant cause could not be ruled out. He underwent an exploratory laparotomy and frozen sections confirmed the diagnosis of LSP. An internal biliary bypass was performed using a Roux loop of jejunum, and the patient made an uneventful recovery. This case illustrates the difficulty in distinguishing LSP from pancreatic carcinoma preoperatively
Genetic dissection of mammalian ERAD through comparative haploid and CRISPR forward genetic screens.
The application of forward genetic screens to cultured human cells represents a powerful method to study gene function. The repurposing of the bacterial CRISPR/Cas9 system provides an effective method to disrupt gene function in mammalian cells, and has been applied to genome-wide screens. Here, we compare the efficacy of genome-wide CRISPR/Cas9-mediated forward genetic screens versus gene-trap mutagenesis screens in haploid human cells, which represent the existing 'gold standard' method. This head-to-head comparison aimed to identify genes required for the endoplasmic reticulum-associated degradation (ERAD) of MHC class I molecules. The two approaches show high concordance (>70%), successfully identifying the majority of the known components of the canonical glycoprotein ERAD pathway. Both screens also identify a role for the uncharacterized gene TXNDC11, which we show encodes an EDEM2/3-associated disulphide reductase. Genome-wide CRISPR/Cas9-mediated screens together with haploid genetic screens provide a powerful addition to the forward genetic toolbox.This work was supported by the Wellcome Trust, through a Principal Research Fellowship to P.J.L. and PhD studentships to S.A.M. and I.A.T., the NIHR Cambridge BRC and the Lundbeck Foundation (L.C.C. and L.E.). The CIMR is in receipt of a Wellcome Trust strategic award.This is the final version of the article. It first appeared from Nature Publishing Group via http://dx.doi.org/10.1038/ncomms11786
Detection of natural infection with Mycobacterium intracellulare in healthy wild-caught Chacma baboons (Papio ursinus) by ESAT-6 and CFP-10 IFN-γ ELISPOT tests following a tuberculosis outbreak
<p>Abstract</p> <p>Background</p> <p>Both tuberculous and non-tuberculous mycobacteria can cause infection in nonhuman primates (NHP), indicating the existence of potential zoonotic transmission between these animals and visitors to zoos or animal handlers in primate facilities. Screening of mycobacterial infections in NHP is traditionally done by tuberculin skin test (TST), which is unable to distinguish between pathogenic and non-pathogenic mycobacterial infections. In this study, we investigated the use of ESAT-6 and CFP-10 for detection of mycobacterial infections in a wild-caught baboon colony after one baboon died of tuberculosis (TB).</p> <p>Methods</p> <p>Peripheral blood lymphocytes for interferon-gamma enzyme-linked immunospot assay (IFN-γ ELISPOT) assay were obtained from TST positive baboons and those in contact with tuberculous baboons before being euthanased, autopsied and lung tissues taken for histology and mycobacterial culture.</p> <p>Results</p> <p>Both ESAT-6 and CFP-10 IFN-γ ELISPOT assays were able to detect early <it>M. tuberculosis </it>but also <it>M. intracellulare </it>infection. Although this indicates potential cross-reactivity with <it>M. intracellulare </it>antigens, the method was able to distinguish <it>M. bovis </it>BCG vaccination from <it>M. tuberculosis </it>infection. This assay performed better than the TST, which failed to detect one <it>M. tuberculosis </it>and two early <it>M. intracellulare </it>infections.</p> <p>Conclusion</p> <p>These results suggest that the IFN-γ ELISPOT assay could improve the detection of <it>M tuberculosis </it>infections when screening NHP. There is some doubt, however, concerning specificity, as the assay scored positive three animals infected with <it>M. intracellulare</it>.</p
Biomarker-based asthma phenotypes of corticosteroid response
BackgroundAsthma is a heterogeneous disease with different phenotypes. Inhaled corticosteroid (ICS) therapy is a mainstay of treatment for asthma, but the clinical response to ICSs is variable.ObjectiveWe hypothesized that a panel of inflammatory biomarkers (ie, fraction of exhaled nitric oxide [Feno], sputum eosinophil count, and urinary bromotyrosine [BrTyr] level) might predict steroid responsiveness.MethodsThe original study from which this analysis originates comprised 2 phases: a steroid-naive phase 1 and a 28-day trial of ICSs (phase 2) during which Feno values, sputum eosinophil counts, and urinary BrTyr levels were measured. The response to ICSs was based on clinical improvements, including a 12% or greater increase in FEV1, a 0.5-point or greater decrease in Asthma Control Questionnaire score, and 2 doubling dose or greater increase in provocative concentration of adenosine 5′-monophosphate causing a 20% decrease in FEV1 (PC20AMP). Healthy control subjects were also evaluated in this study for comparison of biomarkers with those seen in asthmatic patients.ResultsAsthmatic patients had higher than normal Feno values, sputum eosinophil counts, and urinary BrTyr levels during the steroid-naive phase and after ICS therapy. After 28-day trial of ICSs, Feno values decreased in 82% of asthmatic patients, sputum eosinophil counts decreased in 60%, and urinary BrTyr levels decreased in 58%. Each of the biomarkers at the steroid-naive phase had utility for predicting steroid responsiveness, but the combination of high Feno values and high urinary BrTyr levels had the best power (13.3-fold, P < .01) to predict a favorable response to ICS therapy. However, the magnitude of the decrease in biomarker levels was unrelated to the magnitude of clinical response to ICS therapy.ConclusionA noninvasive panel of biomarkers in steroid-naive asthmatic patients predicts clinical responsiveness to ICS therapy
Photochemical pump and NMR probe : Chemically created NMR coherence on a microsecond time scale
We report pump-probe experiments employing laser-synchronized reactions of para-hydrogen (para-H2) with transition metal dihydride complexes in conjunction with nuclear magnetic resonance (NMR) detection. The pump-probe experiment consists of a single nanosecond laser pump pulse followed, after a precisely defined delay, by a single radio frequency (rf) probe pulse. Laser irradiation eliminates H2 from either Ru(PPh3) 3(CO)(H)2 1 or cis-Ru(dppe)2(H)2 2 in C6D6 solution. Reaction with para-H2 then regenerates 1 and 2 in a well-defined nuclear spin state. The rf probe pulse produces a high-resolution, single-scan 1H NMR spectrum that can be recorded after a pump-probe delay of just 10 μs. The evolution of the spectra can be followed as the pump-probe delay is increased by micro- or millisecond increments. Due to the sensitivity of this para-H2 experiment, the resulting NMR spectra can have hydride signal-to-noise ratios exceeding 750:1. The spectra of 1 oscillate in amplitude with frequency 1101 ± 3 Hz, the chemical shift difference between the chemically inequivalent hydrides. The corresponding hydride signals of 2 oscillate with frequency 83 ± 5 Hz, which matches the difference between couplings of the hydrides to the equatorial 31P nuclei. We use the product operator formalism to show that this oscillatory behavior arises from a magnetic coherence in the plane orthogonal to the magnetic field that is generated by use of the laser pulse without rf initialization. In addition, we demonstrate how chemical shift imaging can differentiate the region of laser irradiation thereby distinguishing between thermal and photochemical reactivity within the NMR tube
Regulation of branching dynamics by axon-intrinsic asymmetries in Tyrosine Kinase Receptor signaling
Axonal branching allows a neuron to connect to several targets, increasing neuronal circuit complexity. While axonal branching is well described, the mechanisms that control it remain largely unknown. We find that in the Drosophila CNS branches develop through a process of excessive growth followed by pruning. In vivo high-resolution live imaging of developing brains as well as loss and gain of function experiments show that activation of Epidermal Growth Factor Receptor (EGFR) is necessary for branch dynamics and the final branching pattern. Live imaging also reveals that intrinsic asymmetry in EGFR localization regulates the balance between dynamic and static filopodia. Elimination of signaling asymmetry by either loss or gain of EGFR function results in reduced dynamics leading to excessive branch formation. In summary, we propose that the dynamic process of axon branch development is mediated by differential local distribution of signaling receptors
Increased risk of A(H1N1)pdm09 influenza infection in UK pig industry workers compared to a general population cohort
Background: Pigs are mixing vessels for influenza viral reassortment but the extent of influenza transmission between swine and humans is not well understood.
Objectives: To assess whether occupational exposure to pigs is a risk factor for human infection with human and swine-adapted influenza viruses.
Methods: UK pig industry workers were frequency-matched on age, region, sampling month, and gender with a community-based comparison group from the Flu Watch study. HI assays quantified antibodies for swine and human A(H1) and A(H3) influenza viruses (titres≥40 considered seropositive and indicative of infection). Virus-specific associations between seropositivity and occupational pig exposure were examined using multivariable regression models adjusted for vaccination. Pigs on the same farms were also tested for seropositivity.
Results: 42% of pigs were seropositive to A(H1N1)pdm09. Pig industry workers showed evidence of increased odds of A(H1N1)pdm09 seropositivity compared to the comparison group, albeit with wide confidence intervals (CI), Adjusted Odds Ratio after accounting for possible cross reactivity with other swine A(H1) viruses (aOR) 25.30, 95% CI [1.44-536.34], p=0.028.
Conclusion: The results indicate that A(H1N1)pdm09 virus was common in UK pigs during the pandemic and subsequent period of human A(H1N1)pdm09 circulation, and occupational exposure to pigs was a risk factor for human infection. Influenza immunization of pig industry workers may reduce transmission and the potential for virus reassortment
Adenosine preconditioning attenuates hepatic reperfusion injury in the rat by preventing the down-regulation of endothelial nitric oxide synthase
BACKGROUND: Previous work has suggested that in the liver, adenosine preconditioning is mediated by nitric oxide. Whether the endothelial isoform of nitric oxide synthase plays a part in this mechanism has however not yet been investigated. METHODS: Wistar rats were used (6 in each group) – Groups: (1) sham, (2) ischemia-reperfusion, (3) adenosine + ischemia-reperfusion, (4) endothelial isoform inhibitor + adenosine + ischemia-reperfusion. RESULTS: Using immunohistochemistry, this study has revealed a decrease in the expression of endothelial nitric oxide synthase following hepatic ischemia-reperfusion. This was prevented by adenosine pre-treatment. When an inhibitor of endothelial nitric oxide synthase was administered prior to adenosine pre-treatment, pre-conditioning did not occur despite normal expression of endothelial nitric oxide synthase. CONCLUSIONS: These findings suggest that adenosine attenuates hepatic injury by preventing the downregulation of endothelial nitric oxide synthase that occurs during ischemia-reperfusion
Increased risk of A(H1N1)pdm09 influenza infection in UK pig industry workers compared to a general population cohort.
BACKGROUND: Pigs are mixing vessels for influenza viral reassortment, but the extent of influenza transmission between swine and humans is not well understood. OBJECTIVES: To assess whether occupational exposure to pigs is a risk factor for human infection with human and swine-adapted influenza viruses. METHODS: UK pig industry workers were frequency-matched on age, region, sampling month, and gender with a community-based comparison group from the Flu Watch study. HI assays quantified antibodies for swine and human A(H1) and A(H3) influenza viruses (titres ≥ 40 considered seropositive and indicative of infection). Virus-specific associations between seropositivity and occupational pig exposure were examined using multivariable regression models adjusted for vaccination. Pigs on the same farms were also tested for seropositivity. RESULTS: Forty-two percent of pigs were seropositive to A(H1N1)pdm09. Pig industry workers showed evidence of increased odds of A(H1N1)pdm09 seropositivity compared to the comparison group, albeit with wide confidence intervals (CIs), adjusted odds ratio after accounting for possible cross-reactivity with other swine A(H1) viruses (aOR) 25·3, 95% CI (1·4-536·3), P = 0·028. CONCLUSION: The results indicate that A(H1N1)pdm09 virus was common in UK pigs during the pandemic and subsequent period of human A(H1N1)pdm09 circulation, and occupational exposure to pigs was a risk factor for human infection. Influenza immunisation of pig industry workers may reduce transmission and the potential for virus reassortment.This work was supported by joint funding from the
Biotechnology and Biological Sciences Research Council
(BBSRC), the Medical Research Council (MRC), and the
Wellcome Trust (WT) [(BBSRC/MRC/WT) BB/H014306/1;
(MRC/WT) MC_U122785833; (MRC) G0800767 and
G0600511]; Alborada Trust (to J.L.N.W.); the RAPIDD
programme of the Science & Technology Directorate (to
J.L.N.W.); US Department of Homeland Security (to
J.L.N.W.); and the Fogarty International Center at the
National Institutes of Health (to J.L.N.W.). DAI is supported
by a fellowship from the National Institute for Health
Research (NIHR) (PDF-2012-05-305) (this research is independent
and the views expressed in this publication are those
of the authors and not necessarily those of the Department of
Health or NIHR).This is the final version of the article. It first appeared from Wiley via https://doi.org//10.1111/irv.12364/abstract
- …