102 research outputs found

    Does virulence assessment of Vibrio anguillarum using sea bass (Dicentrarchus labrax) larvae correspond with genotypic and phenotypic characterization?

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    Background: Vibriosis is one of the most ubiquitous fish diseases caused by bacteria belonging to the genus Vibrio such as Vibrio (Listonella) anguillarum. Despite a lot of research efforts, the virulence factors and mechanism of V. anguillarum are still insufficiently known, in part because of the lack of standardized virulence assays. Methodology/Principal Findings: We investigated and compared the virulence of 15 V. anguillarum strains obtained from different hosts or non-host niches using a standardized gnotobiotic bioassay with European sea bass (Dicentrarchus labrax L.) larvae as model hosts. In addition, to assess potential relationships between virulence and genotypic and phenotypic characteristics, the strains were characterized by random amplified polymorphic DNA (RAPD) and repetitive extragenic palindromic PCR (rep-PCR) analyses, as well as by phenotypic analyses using Biolog's Phenotype MicroArray (TM) technology and some virulence factor assays. Conclusions/Significance: Virulence testing revealed ten virulent and five avirulent strains. While some relation could be established between serotype, genotype and phenotype, no relation was found between virulence and genotypic or phenotypic characteristics, illustrating the complexity of V. anguillarum virulence. Moreover, the standardized gnotobiotic system used in this study has proven its strength as a model to assess and compare the virulence of different V. anguillarum strains in vivo. In this way, the bioassay contributes to the study of mechanisms underlying virulence in V. anguillarum

    Mucosal Gene Expression of Antimicrobial Peptides in Inflammatory Bowel Disease Before and After First Infliximab Treatment

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    Background: Antimicrobial peptides (AMPs) protect the host intestinal mucosa against microorganisms. Abnormal expression of defensins was shown in inflammatory bowel disease (IBD), but it is not clear whether this is a primary defect. We investigated the impact of anti-inflammatory therapy with infliximab on the mucosal gene expression of AMPs in IBD. Methodology/Principal Findings: Mucosal gene expression of 81 AMPs was assessed in 61 IBD patients before and 4-6 weeks after their first infliximab infusion and in 12 control patients, using Affymetrix arrays. Quantitative real-time reverse-transcription PCR and immunohistochemistry were used to confirm microarray data. The dysregulation of many AMPs in colonic IBD in comparison with control colons was widely restored by infliximab therapy, and only DEFB1 expression remained significantly decreased after therapy in the colonic mucosa of IBD responders to infliximab. In ileal Crohn's disease (CD), expression of two neuropeptides with antimicrobial activity, PYY and CHGB, was significantly decreased before therapy compared to control ileums, and ileal PYY expression remained significantly decreased after therapy in CD responders. Expression of the downregulated AMPs before and after treatment (DEFB1 and PYY) correlated with villin 1 expression, a gut epithelial cell marker, indicating that the decrease is a consequence of epithelial damage. Conclusions/Significance: Our study shows that the dysregulation of AMPs in IBD mucosa is the consequence of inflammation, but may be responsible for perpetuation of inflammation due to ineffective clearance of microorganisms

    Beliefs, barriers and preferences of European overweight women to adopt a healthier lifestyle in pregnancy to minimize risk of developing gestational diabetes mellitus: an explorative study

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    Introduction: Overweight and obese women are at high risk of developing gestational diabetes mellitus (GDM). Lifestyle programs might help curb the GDM risk. We explored beliefs, perceived barriers and preferences regarding lifestyle changes among overweight European pregnant women to help inform the development of future high quality lifestyle interventions. Methods: An explorative mixed methods, two-staged study was conducted to gather information from pregnant European women (BMI≥25kg/m2). In three European countries (Belgium, Netherlands, United Kingdom) interviews were conducted, followed by questionnaires in six other European countries (Austria, Denmark, Ireland, Italy, Poland, Spain). Content analysis, descriptive and chi square statistics were applied (p<0.05). Results: Women preferred to obtain detailed information about their personal risk. The health of their baby was major motivating factor. Perceived barriers for physical activity included pregnancy-specific issues such as tiredness and experiencing physical complaints. Insufficient time was a barrier more frequently reported by women with children. Abstaining from snacking was identified as a challenge for the majority of women, especially for those without children. Women preferred to obtain support from their partner, as well as health professionals and valued flexible lifestyle programs. Conclusions: Healthcare professionals need to inform overweight pregnant women about their personal risk, discuss lifestyle modification and assist in weight management. Lifestyle programs should be tailored to the individual, taking into account barriers experienced by overweight first-time mothers and multipara women

    Using the World Wide Web in secondary schools: Web for schools, a european project

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    How to describe multiple versions of the same?

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    The IEEE LTSC Learning Object Metadata (LOM) standard has become the primary standard for describing learning objects and is now used on a massive scale. This paper proposes and discusses three solutions for describing different versions of the same learning object. Such versions could be resources in different formats, languages, accessibility, etc. Currently, there is no best practice in current standards like LOM etc. how to capture this information. We propose a recursive LOM approach where a LOM instance can be an aggregate of multiple LOM instances.status: publishe

    Special issue: learning objects in context guest editors introduction

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    Welcome to this special issue on "learning objects in context"! The papers in this issue have their origins in a workshop we organized in March 2005, with the support of the ProLearn network of excellence on professional learning[1] and the iClass project[2]. The papers in this issue focus specifically on the context in which learning objects are deployed: this theme is quite varied and picks up on the message that “if content is king, then context is queen.” Overall, the main aim is to exploit data available about user context to: - generate metadata automatically, either during the authoring process, from the author’s context, when information about the intended use is more easily available; or while the learner is working with the learning object, in order to capture his feedback, which can then be used later to help guide decisions on the appropriateness of the same object for other learners; - personalize the selection of relevant learning objects, by selecting objects that satisfy conditions that reflect the requirements of the context; and - adapt the behavior of a learning object to the specific characteristics of the context.status: publishe
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