113 research outputs found

    Functional and Immunological Relevance of Anaplasma marginale Major Surface Protein 1a Sequence and Structural Analysis.

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    Bovine anaplasmosis is caused by cattle infection with the tick-borne bacterium, Anaplasma marginale. The major surface protein 1a (MSP1a) has been used as a genetic marker for identifying A. marginale strains based on N-terminal tandem repeats and a 5'-UTR microsatellite located in the msp1a gene. The MSP1a tandem repeats contain immune relevant elements and functional domains that bind to bovine erythrocytes and tick cells, thus providing information about the evolution of host-pathogen and vector-pathogen interactions. Here we propose one nomenclature for A. marginale strain classification based on MSP1a. All tandem repeats among A. marginale strains were classified and the amino acid variability/frequency in each position was determined. The sequence variation at immunodominant B cell epitopes was determined and the secondary (2D) structure of the tandem repeats was modeled. A total of 224 different strains of A. marginale were classified, showing 11 genotypes based on the 5'-UTR microsatellite and 193 different tandem repeats with high amino acid variability per position. Our results showed phylogenetic correlation between MSP1a sequence, secondary structure, B-cell epitope composition and tick transmissibility of A. marginale strains. The analysis of MSP1a sequences provides relevant information about the biology of A. marginale to design vaccines with a cross-protective capacity based on MSP1a B-cell epitopes

    Linaclotide utilization and potential for off-label use and misuse in three European countries

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    INTRODUCTION Linaclotide is approved for adults with moderate-to-severe irritable bowel syndrome (IBS) with constipation (IBS-C). Linaclotide is not indicated for weight loss or for patients with inflammatory bowel disease (IBD); it is contraindicated in patients with mechanical bowel obstruction (MBO). Some patients with obesity or eating disorders (ED) may use linaclotide off-label for weight loss or as a laxative. OBJECTIVES To describe the use of linaclotide in clinical practice, including patients with potential for off-label use or misuse. METHODS Post-authorization safety study conducted in three databases from the linaclotide launch date to 2017: the Clinical Practice Research Datalink in the United Kingdom (UK), the Information System for Research in Primary Care database in Spain and the linked Patient, Prescription and Causes of Death Registries in Sweden. Cohorts of patients were identified as having IBS using diagnostic and treatment codes; IBS subtypes were identified using symptoms and treatment codes; patients with obesity, ED, MBO, and IBD were identified using diagnostic codes or body mass index. RESULTS There were 1319, 1981, and 5081 linaclotide users from the United Kingdom, Spain, and Sweden with a median age of 45, 57, and 51 years, respectively; most were females. In the United Kingdom, Spain, and Sweden, respectively: 59.0%, 60.3%, and 31.3% of linaclotide users had an IBS diagnosis recorded, and among those, 68.8%, 61.3%, and 92.7% were classified as IBS-C. The proportions of linaclotide users considered at risk for potential off-label use for weight loss or as a laxative were 17.1%, 29.7%, and 1.7%, and the proportions of users considered at risk of misuse due to a history of MBO or IBD were 3.5%, 4.6%, and 5.7% in the United Kingdom, Spain, and Sweden, respectively. CONCLUSIONS Potential linaclotide off-label use and misuse appears limited, as evidenced by the small sizes of the patient subgroups at risk for off-label use and misuse

    Development of an In Vitro Compartmentalization Screen for High-Throughput Directed Evolution of [FeFe] Hydrogenases

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    BACKGROUND: [FeFe] hydrogenase enzymes catalyze the formation and dissociation of molecular hydrogen with the help of a complex prosthetic group composed of common elements. The development of energy conversion technologies based on these renewable catalysts has been hindered by their extreme oxygen sensitivity. Attempts to improve the enzymes by directed evolution have failed for want of a screening platform capable of throughputs high enough to adequately sample heavily mutated DNA libraries. In vitro compartmentalization (IVC) is a powerful method capable of screening for multiple-turnover enzymatic activity at very high throughputs. Recent advances have allowed [FeFe] hydrogenases to be expressed and activated in the cell-free protein synthesis reactions on which IVC is based; however, IVC is a demanding technique with which many enzymes have proven incompatible. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe an extremely high-throughput IVC screen for oxygen-tolerant [FeFe] hydrogenases. We demonstrate that the [FeFe] hydrogenase CpI can be expressed and activated within emulsion droplets, and identify a fluorogenic substrate that links activity after oxygen exposure to the generation of a fluorescent signal. We present a screening protocol in which attachment of mutant genes and the proteins they encode to the surfaces of microbeads is followed by three separate emulsion steps for amplification, expression, and evaluation of hydrogenase mutants. We show that beads displaying active hydrogenase can be isolated by fluorescence-activated cell-sorting, and we use the method to enrich such beads from a mock library. CONCLUSIONS/SIGNIFICANCE: [FeFe] hydrogenases are the most complex enzymes to be produced by cell-free protein synthesis, and the most challenging targets to which IVC has yet been applied. The technique described here is an enabling step towards the development of biocatalysts for a biological hydrogen economy

    Impacting Children’s Physical and Mental Health through Kinesiology Support in Clinical Care: A Randomized Controlled Trial Protocol

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    Objectives To enhance the confidence of children and adolescents with medical conditions and disabilities to engage in healthy, active lifestyles. Children with medical conditions and disabilities often exhibit more sedentary lifestyles relative to peers and are at increased risk of poor health outcomes. Clinical experience suggests physical activity confidence is an important factor influencing physical activity participation. Methods This randomized controlled trial evaluates an evidence-based intervention targeting physical activity confidence among children and adolescents with medical conditions and disabilities. Potential participants, 8 to 18 years of age diagnosed with a medical condition or disability, will be screened for adequate physical activity motivation but a lack confidence. Consenting participants (n=128) will be randomized 1:1 to a 12-week in-person or virtual physical activity intervention (24 hours/week total) led by a Registered Kinesiologist or control (assessments only). The intervention will combine physical activity participation with education about physical activity knowledge, goal setting, motivation and self-management. Primary outcomes are self-reported physical activity confidence and motivation at baseline, post-intervention and three months following intervention completion. A secondary outcome will be daily physical activity minutes assessed by accelerometry. A repeated measures mixed model will be used to compare outcomes between the in-person intervention, virtual intervention, and control groups (alpha=0.05). Conclusions This trial aims to assess the impact of a novel application of behaviour change theory on physical activity confidence among children and adolescents living with medical conditions or disabilities. Increased physical activity confidence, knowledge and skills could enable these youth to lead a more active lifestyle

    Protein C Inhibitor—A Novel Antimicrobial Agent

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    Protein C inhibitor (PCI) is a heparin-binding serine proteinase inhibitor belonging to the family of serpin proteins. Here we describe that PCI exerts broad antimicrobial activity against bacterial pathogens. This ability is mediated by the interaction of PCI with lipid membranes, which subsequently leads to their permeabilization. As shown by negative staining electron microscopy, treatment of Escherichia coli or Streptococcus pyogenes bacteria with PCI triggers membrane disruption followed by the efflux of bacterial cytosolic contents and bacterial killing. The antimicrobial activity of PCI is located to the heparin-binding site of the protein and a peptide spanning this region was found to mimic the antimicrobial activity of PCI, without causing lysis or membrane destruction of eukaryotic cells. Finally, we show that platelets can assemble PCI on their surface upon activation. As platelets are recruited to the site of a bacterial infection, these results may explain our finding that PCI levels are increased in tissue biopsies from patients suffering from necrotizing fasciitis caused by S. pyogenes. Taken together, our data describe a new function for PCI in innate immunity

    STAT3/LKB1 controls metastatic prostate cancer by regulating mTORC1/CREB pathway

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    Prostate cancer (PCa) is a common and fatal type of cancer in men. Metastatic PCa (mPCa) is a major factor contributing to its lethality, although the mechanisms remain poorly understood. PTEN is one of the most frequently deleted genes in mPCa. Here we show a frequent genomic co-deletion of PTEN and STAT3 in liquid biopsies of patients with mPCa. Loss of Stat3 in a Pten-null mouse prostate model leads to a reduction of LKB1/pAMPK with simultaneous activation of mTOR/CREB, resulting in metastatic disease. However, constitutive activation of Stat3 led to high LKB1/pAMPK levels and suppressed mTORC1/CREB pathway, preventing mPCa development. Metformin, one of the most widely prescribed therapeutics against type 2 diabetes, inhibits mTORC1 in liver and requires LKB1 to mediate glucose homeostasis. We find that metformin treatment of STAT3/AR-expressing PCa xenografts resulted in significantly reduced tumor growth accompanied by diminished mTORC1/CREB, AR and PSA levels. PCa xenografts with deletion of STAT3/AR nearly completely abrogated mTORC1/CREB inhibition mediated by metformin. Moreover, metformin treatment of PCa patients with high Gleason grade and type 2 diabetes resulted in undetectable mTORC1 levels and upregulated STAT3 expression. Furthermore, PCa patients with high CREB expression have worse clinical outcomes and a significantly increased risk of PCa relapse and metastatic recurrence. In summary, we have shown that STAT3 controls mPCa via LKB1/pAMPK/mTORC1/CREB signaling, which we have identified as a promising novel downstream target for the treatment of lethal mPCa

    Scanning tunneling microscopy and atomic force microscopy in the characterization of activated graphite electrodes

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    Sir: To date there have been many methods described to activate carbon electrodes, including electrochemical treatment (1-1 7), laser irradiation (18-21), radio-frequency (RF) plasma (22), and heat treatment (23-26). These methods were developed empirically, and only now is an understanding of parameters controlling surface activity beginning to emerge (20,27). Electrochemical treatment and laser irradiation are particularly attractive treatments because they are relatively inexpensive, are quick, and can be performed without removing the electrode from solution. Activation, common to these procedures, may be attributable to an increase in the exposed edge plane density, which has been associated with faster kinetics (14,20). Copper deposition in conjunction with scanning electron microscopy (SEM) has shown an increase in the density of localized defects on active surfaces (15); an increase in surface activity is associated with an increase in the density of the localized defects (15). Scanning tunneling microscopy (STM), phase detection microscopy, and SEM have also been used to study the effects of electrochemical treatment of highly oriented pyrolytic graphite (HOPG) (13) and glassy carbon (GC) (16,17). These studies have suggested an increase in surface roughness consistent with an increase in the density of exposed edge planes

    ARIA 2016 : Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

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    The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma and rhinitis and (3) to develop guidelines with all stakeholders that could be used globally for all countries and populations. ARIA-disseminated and implemented in over 70 countries globally-is now focusing on the implementation of emerging technologies for individualized and predictive medicine. MASK [MACVIA (Contre les Maladies Chroniques pour un Vieillissement Actif)-ARIA Sentinel NetworK] uses mobile technology to develop care pathways for the management of rhinitis and asthma by a multi-disciplinary group and by patients themselves. An app (Android and iOS) is available in 20 countries and 15 languages. It uses a visual analogue scale to assess symptom control and work productivity as well as a clinical decision support system. It is associated with an inter-operable tablet for physicians and other health care professionals. The scaling up strategy uses the recommendations of the European Innovation Partnership on Active and Healthy Ageing. The aim of the novel ARIA approach is to provide an active and healthy life to rhinitis sufferers, whatever their age, sex or socio-economic status, in order to reduce health and social inequalities incurred by the disease.Peer reviewe
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