1,109 research outputs found

    Characterization of Borrelia Burgdorferi BlyA and BlyB Proteins: a Prophage-Encoded Holin-Like System

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    The conserved cp32 plasmid family of Borrelia burgdorferi was recently shown to be packaged into a bacteriophage particle (C. H. Eggers and D. S. Samuels, J. Bacteriol. 181:7308-7313, 1999), This plasmid encodes BlyA, a 7.4-kDa membrane-interactive protein, and BlyB, an accessory protein, which were previously proposed to comprise a hemolysis system. Our genetic and biochemical evidence suggests that this hypothesis is incorrect and that BlyA and BlyB function instead as a prophage-encoded holin or holin-like system for this newly described bacteriophage, An Escherichia coli mutant containing the blyAB locus that was defective for the normally cryptic host hemolysin SheA was found to be nonhemolytic, suggesting that induction of sheA by blyAB expression was responsible for the hemolytic activity observed previously, Analysis of the structural features of BlyA indicated greater structural similarity to bacteriophage-encoded holins than to hemolysins, Consistent with holin characteristics, subcellular localization studies with E. coli and B. burgdorferi indicated that BlyA is solely membrane associated and that BlyB is a soluble protein. Furthermore, BlyA exhibited a holin-like function by promoting the endolysin-dependent lysis of an induced lambda lysogen that was defective in the holin gene. Finally, induction of the cp32 prophage in B. burgdorferi dramatically stimulated blyAB expression. Our results provide the first evidence of a prophage-encoded holin within Borrelia

    Testing the effects on information use by older versus younger women of modality and narration style in a hospital report card

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    BACKGROUND: Hospital report cards (HRCs) are usually presented in a textual and factual format, likely hampering information processing. OBJECTIVE: This study aimed to investigate the effects of audiovisual and narrative information in HRCs on user responses, and to test differences between older and younger women. DESIGN: A 2 (modality [textual vs. audiovisual])ā€‰Ć—ā€‰3 (narration style [factual vs. process narrative vs. experience narrative]) online experiment was conducted. Information about breast cancer care was used as a case example. Age (younger [<65] vs. older [ā‰„65]) was included as a potential effect modifier. SETTING AND PARTICIPANTS: A total of 631 diseaseā€naĆÆve women (M (age)ā€‰=ā€‰56.06) completed an online survey. The outcomes were perceived cognitive load, satisfaction, comprehension, information recall and decisional conflict. Data were analysed using AN(C)OVAs. RESULTS: Audiovisual (vs. textual) information resulted in higher information satisfaction across age groups, but was associated with lower comprehension in older women. An experience narrative (vs. factual information) increased satisfaction with attractiveness and emotional support of the information only in older women. A threeā€way interaction effect was found, suggesting that older women were most satisfied with the comprehensibility of audiovisual factual or textual process narrative information. Younger women were most satisfied with the comprehensibility of audiovisual process narrative or textual factual information. DISCUSSION AND CONCLUSION: Audiovisual and narrative information in an HRC showed beneficial effects on satisfaction measures. In particular, audiovisual information could be incorporated into HRCs to increase satisfaction with information. PUBLIC CONTRIBUTION: Lay persons helped in optimizing the visuals used in the stimulus materials by checking for clarity

    Dermal C4d Deposition and Neutrophil Alignment Along the Dermal-Epidermal Junction as a Diagnostic Adjunct for Hypocomplementemic Urticarial Vasculitis (Anti-C1q Vasculitis) and Underlying Systemic Disease

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    Urticarial vasculitis (UV) is a clinicopathologic entity characterized by persistent urticarial lesions with biopsy features of vasculitis. Currently, only certain clinical features such as arthralgia and serum complement concentrations are used to identify UV patients at risk for an underlying systemic disease. Hypocomplementemic urticarial vasculitis (HUV) is in contrast to normocomplementemic urticarial vasculitis (NUV), strongly associated with underlying systemic disease, especially systemic lupus erythematosus (SLE). The aim of this study was to find specific histopathological features associated with HUV and underlying systemic disease in UV. In addition, the use of complement C4d deposition in skin biopsies was evaluated as a diagnostic adjunct for HUVand UV-associated systemic disease. In this retrospective study, the clinical, histopathological, and immunohistological (C4d) features of 43 patients with UV were compared between HUV and NUV and analyzed for association with UV-associated systemic disease. Eight of 43 patients with UV (19%) had hypocomplementemia

    Complement activation in inflammatory skin diseases

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    The complement system is a fundamental part of the innate immune system, playing a crucial role in host defense against various pathogens, such as bacteria, viruses, and fungi. Activation of complement results in production of several molecules mediating chemotaxis, opsonization, and mast cell degranulation, which can contribute to the elimination of pathogenic organisms and inflammation. Furthermore, the complement system also has regulating properties in inflammatory and immune responses. Complement activity in diseases is rather complex and may involve both aberrant expression of complement and genetic deficiencies of complement components or regulators. The skin represents an active immune organ with complex interactions between cellular components and various mediators. Complement involvement has been associated with several skin diseases, such as psoriasis, lupus erythematosus, cutaneous vasculitis, urticaria, and bullous dermatoses. Several triggers including auto-antibodies and micro-organisms can activate complement, while on the other hand complement deficiencies can contribute to impaired immune complex clearance, leading to disease. This review provides an overview of the role of complement in inflammatory skin diseases and discusses complement factors as potential new targets for therapeutic intervention
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