470 research outputs found

    Idiopathic Low-Flow Priapism in Prepuberty: A Case Report and a Review of Literature

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    Introduction. The incidence of priapism in adults is higher than in children. Although approximately 50% of all episodes of priapism are thought to be idiopathic, there are a number of known specific causes of this disorder. In adults intracavernous therapy with papaverine, phentolamine, alprostadil or combinations of these agents is the most common cause of ischemic priapism. In children the most common etiology is sickle cell anemia for low-flow priapism or post-traumatic high-flow priapism. We present a 13-year-old boy, not sexually active presented to our outpatient clinic suffering from long standing (3.5 hours) sustained painful erection. To the best of our knowledge the idiopathic low-flow priapism in pre-pubertal boy was not reported before in literature. Our case is the first case to be reported in pre-pubertal age. Conclusion. In pre-pubertal boys idiopathic recurrent priapism is a rare condition. In the literature, several empirical therapies are described. Recently, it is postulated that a low dose of a PDE5 inhibitor. The early conservative management is the best treatment option to safe the corporeal smooth muscles from irreversible damage

    Immobilization by surface conjugation of cyclic peptides for effective mimicry of the HCV-envelope E2 protein as a strategy toward synthetic vaccines

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    Mimicry of the binding interface of antibody-antigen interactions using peptide-based modulators (i.e. epitope mimics) has promising applications for vaccine design. These epitope mimics can be synthesized in a streamlined and straightforward fashion, thereby allowing for high-throughput analysis. The design of epitope mimics is highly influenced by their spatial configuration and structural conformation. It is widely assumed that for proper mimicry sufficient conformational constraints have to be implemented. This paper describes the synthesis of bromide derivatives functional-ized with a flexible TEG linker equipped with a thiol-moiety that could be used to support cyclic or linear peptides. The cyclic and linear epitope mimics were covalently conjugated via the free thiol-moiety on maleimide-activated plate sur-faces. The resulting covalent, uniform, and oriented coated surface of cyclic or linear epitope mimics were subjected to an ELISA to investigate the effect of peptide cyclization with respect to mimicry of an antigen-antibody interaction of the HCV E2 glycoprotein. To our knowledge, the benefit of cyclized peptides over linear peptides has been clearly demon-strated here for the first time. Cyclic epitope mimics, and not the linear epitope mimics, demonstrated specificity towards their monoclonal antibodies HC84.1 and V3.2, respectively. The described strategy for the construction of epitope mimics shows potential for high-throughput screening of key-binding residues by simply changing the amino-acid sequences within synthetic peptides. In this way, leucine-438 has been identified as a key-binding residue for binding monoclonal antibody V3.2

    Improving the aqueous solubility of HCV-E2 glycoprotein epitope mimics by cyclization using polar hinges

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    In this research we describe the improvement of the water‐solubility of cyclic epitope mimics based on the HCV E2 glycoprotein by incorporation of suitable polar hinges. The poor solubility of epitope mimics based on peptide sequences in the envelope (E2) protein hampered their synthesis and purification and made it very difficult to prepare the molecular constructs for evaluation of their bioactivity. Since changes in the amino acid composition are hardly possible in these epitope mimics in order to increase water‐solubility, a polar cyclization hinge may offer a remedy leading to a significant increase of polarity and therefore water solubility. These polar hinges were applied in the synthesis of better water‐soluble HCV‐E2 epitopes. An azide functionality in the polar hinges allowed attachment of a tetraethylene glycol linker by Cu‐catalyzed azide‐alkyne cyclo‐addition (CuAAC) for a convenient conjugation to ELISA plates in order to evaluate the bio‐activity of the epitope mimics. The immunoassays showed that the use of more polar cyclization hinges still supported anti‐HCV antibody recognition and did not negatively influence their binding. This significantly increased solubility induced by polar hinges should therefore allow for the molecular construction and ultimate evaluation of synthetic vaccine molecules

    Apolipoprotein E mediates evasion from hepatitis C virus−neutralizing antibodies

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    Background & Aims Efforts to develop an effective vaccine against hepatitis C virus (HCV) have been hindered by the propensity of the virus to evade host immune responses. HCV particles in serum and in cell culture associate with lipoproteins, which contribute to viral entry. Lipoprotein association has also been proposed to mediate viral evasion of the humoral immune response, though the mechanisms are poorly defined. Methods We used small interfering RNAs to reduce levels of apolipoprotein E (apoE) in cell culture−derived HCV−producing Huh7.5-derived hepatoma cells and confirmed its depletion by immunoblot analyses of purified viral particles. Before infection of naïve hepatoma cells, we exposed cell culture−derived HCV strains of different genotypes, subtypes, and variants to serum and polyclonal and monoclonal antibodies isolated from patients with chronic HCV infection. We analyzed the interaction of apoE with viral envelope glycoprotein E2 and HCV virions by immunoprecipitation. Results Through loss-of-function studies on patient-derived HCV variants of several genotypes and subtypes, we found that the HCV particle apoE allows the virus to avoid neutralization by patient-derived antibodies. Functional studies with human monoclonal antiviral antibodies showed that conformational epitopes of envelope glycoprotein E2 domains B and C were exposed after depletion of apoE. The level and conformation of virion-associated apoE affected the ability of the virus to escape neutralization by antibodies. Conclusions In cell-infection studies, we found that HCV-associated apoE helps the virus avoid neutralization by antibodies against HCV isolated from chronically infected patients. This method of immune evasion poses a challenge for the development of HCV vaccines

    Design and synthesis of HCV-E2 glycoprotein epitope mimics in the molecular construction of potential as synthetic vaccines

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    Hepatitis C virus remains a global threat, despite the availability of highly effective direct-acting antiviral (DAA) drugs. With thousands of new infections annually, the need for a prophylactic vaccine is evident. However, traditional vaccine design has been unable to provide effective vaccines so far. Therefore, alternative strategies need to be investigated. In this work, a chemistry-based approach is explored towards fully synthetic peptide-based vaccines using epitope mimicry, by focusing on highly effective and conserved amino acid sequences in HCV, which, upon antibody binding, inhibit its bio-activity. Continuous and discontinuous epitope mimics were both chemically synthesized based on the HCV-E2 glycoprotein while using designed fully synthetic cyclic peptides. These cyclic epitope mimics were assembled on an orthogonally protected scaffold. The scaffolded epitope mimics have been assessed in immunization experiments to investigate the elicitation of anti-HCV-E2 glycoprotein antibodies. The neutralizing potential of the elicited antibodies was investigated, representing a first step in employing chemically synthesized epitope mimics as a novel strategy towards vaccine design

    Explaining the Brexit Vote: A Socioeconomic and Psychological Exploration of the Referendum Vote

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    The proposed book chapter will bring together regional economics and psychological perspectives in relation to Brexit, one year on from Article 50. Extending previous work (Becker, Fetzer, & Novy, 2017; Goodwin and Heath, 2016, Semmens-Wheeler & Hill, 2018) the chapter will exploit regional variations in the Brexit vote to model how well different demographic, socio-economic and other decision-making indicators predict the vote’s outcome by area. Using statistical techniques commonly employed in the literature in both economics and psychology, a focus will be on regional economics, including the role of income/economy vs demography in the vote and psychological perspectives, including the role of empathy and interpersonal reactivity, social dominance orientation, collective self-esteem and modern racial prejudice, among other factors. Drawing on the broader literature, the chapter will consider the potential economic and psychological factors lying behind the results, suggesting possible reasons for regional/demographic variations and areas where further research might be required. An investigation of the literature will discuss developments in these areas to date, as well as provide an overview of research focusing on public perceptions and prospects going forward. This cross-disciplinary chapter will continue to contribute to the growing picture forming around UK’s decision to leave the EU, one year on from Article 50, while providing an insight into the important economic and psychological processes behind Brexit

    Asexuality: Classification and characterization

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    This is a post-print version of the article. The official published version can be obtaineed at the link below.The term “asexual” has been defined in many different ways and asexuality has received very little research attention. In a small qualitative study (N = 4), individuals who self-identified as asexual were interviewed to help formulate hypotheses for a larger study. The second larger study was an online survey drawn from a convenience sample designed to better characterize asexuality and to test predictors of asexual identity. A convenience sample of 1,146 individuals (N = 41 self-identified asexual) completed online questionnaires assessing sexual history, sexual inhibition and excitation, sexual desire, and an open-response questionnaire concerning asexual identity. Asexuals reported significantly less desire for sex with a partner, lower sexual arousability, and lower sexual excitation but did not differ consistently from non-asexuals in their sexual inhibition scores or their desire to masturbate. Content analyses supported the idea that low sexual desire is the primary feature predicting asexual identity

    Autopiquer - a robust and reliable peak detection algorithm for mass spectrometry

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    We present a simple algorithm for robust and unsupervised peak detection by determining a noise threshold in isotopically resolved mass spectrometry data. Solving this problem will greatly reduce the subjective and time consuming manual picking of mass spectral peaks and so will prove beneficial in many research applications. The Autopiquer approach uses autocorrelation to test for the presence of (isotopic) structure in overlapping windows across the spectrum. Within each window, a noise threshold is optimized to remove the most unstructured data whilst keeping as much of the (isotopic) structure as possible. This algorithm has been successfully demonstrated for both peak detection and spectral compression on data from many different classes of mass spectrometer and for different sample types and this approach should also be extendible to other types of data that contain regularly spaced discrete peaks
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