458 research outputs found

    Caveolin-1 protects B6129 mice against Helicobacter pylori gastritis.

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    Caveolin-1 (Cav1) is a scaffold protein and pathogen receptor in the mucosa of the gastrointestinal tract. Chronic infection of gastric epithelial cells by Helicobacter pylori (H. pylori) is a major risk factor for human gastric cancer (GC) where Cav1 is frequently down-regulated. However, the function of Cav1 in H. pylori infection and pathogenesis of GC remained unknown. We show here that Cav1-deficient mice, infected for 11 months with the CagA-delivery deficient H. pylori strain SS1, developed more severe gastritis and tissue damage, including loss of parietal cells and foveolar hyperplasia, and displayed lower colonisation of the gastric mucosa than wild-type B6129 littermates. Cav1-null mice showed enhanced infiltration of macrophages and B-cells and secretion of chemokines (RANTES) but had reduced levels of CD25+ regulatory T-cells. Cav1-deficient human GC cells (AGS), infected with the CagA-delivery proficient H. pylori strain G27, were more sensitive to CagA-related cytoskeletal stress morphologies ("humming bird") compared to AGS cells stably transfected with Cav1 (AGS/Cav1). Infection of AGS/Cav1 cells triggered the recruitment of p120 RhoGTPase-activating protein/deleted in liver cancer-1 (p120RhoGAP/DLC1) to Cav1 and counteracted CagA-induced cytoskeletal rearrangements. In human GC cell lines (MKN45, N87) and mouse stomach tissue, H. pylori down-regulated endogenous expression of Cav1 independently of CagA. Mechanistically, H. pylori activated sterol-responsive element-binding protein-1 (SREBP1) to repress transcription of the human Cav1 gene from sterol-responsive elements (SREs) in the proximal Cav1 promoter. These data suggested a protective role of Cav1 against H. pylori-induced inflammation and tissue damage. We propose that H. pylori exploits down-regulation of Cav1 to subvert the host's immune response and to promote signalling of its virulence factors in host cells

    Becoming original: effects of strategy instruction

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    Visual arts education focuses on creating original visual art products. A means to improve originality is enhancement of divergent thinking, indicated by fluency, flexibility and originality of ideas. In regular arts lessons, divergent thinking is mostly promoted through brainstorming. In a previous study, we found positive effects of an explicit instruction of metacognition on fluency and flexibility in terms of the generation of ideas, but not on the originality of ideas. Therefore, we redesigned the instruction with a focus on building up knowledge about creative generation strategies by adding more complex types of association, and adding generation through combination and abstraction. In the present study, we examined the effects of this intervention by comparing it with regular brainstorming instruction. In a pretest-posttest control group design, secondary school students in the comparison condition received the brainstorm lesson and students in the experimental condition received the newly developed instruction lesson. To validate the effects, we replicated this study with a second cohort. The results showed that in both cohorts the strategy instruction of 50 min had positive effects on students' fluency, flexibility and originality. This study implies that instructional support in building up knowledge about creative generation strategies may improve students' creative processes in visual arts education

    ‘Even though it might take me a while, in the end, I understand it’: a longitudinal case study of interactions between a conceptual change strategy and student motivation, interest and confidence

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    Although there have been many investigations of the social, motivational, and emotional aspects of conceptual change, there have been few studies investigating the intersection of these factors with cognitive aspects in the regular classroom. Using a conceptual change approach, this case study reports experiences of a student of low to average prior attainment who achieved high levels of conceptual gains in five science topics over a two-year period. Her experience in the cognitive, social and affective domains was probed through analysis of interviews, student artefacts, video recordings of classroom learning, pre/post-tests and questionnaire results. For this student, peripheral or incidental persuasion of belonging to a supportive small group initially led to greater engagement with the construction of understanding through production of multiple student-generated representations, resulting in improved self-confidence and high levels of conceptual change. Evidence of transfer from performance to mastery approach goals, adoption of positive activating emotions and increased interest in science were observed. This study highlights that adoption of a multidimensional conceptual change approach with judicious organisation of small groups to support construction of verbal, pictorial and written representations of understanding may bring about changes in motivational stance, self-confidence and emotions to maximise conceptual change

    Self-Regulated Learning in Web-Based Environments: Instructional Tools Designed to Facilitate Cognitive Strategy Use, Metacognitive Processing, and Motivational Beliefs

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    This study investigated strategies teachers can use to improve students' use of self-regulated learning strategies in a Web-based setting. SRL is defined as a learner's intentional efforts to manage and direct complex learning activities and is composed of three primary components including cognitive strategy use, metacognitive processing, and motivational beliefs. These three components are defined relative to note-taking methods (cognitive component), self-monitoring prompts (metacognitive component), and self-efficacy buildng feedback (motivation component). One hundred nineteen students were assigned randomly to one cell in a 2 × 2 × 2 design. Students took notes in a matrix or a free form method from a Web site about educational measurement and either received or did not receive self-monitoring prompts and self-efficacy building feedback. Results indicated note-taking method had the strongest influence on both the amount of information gathered and achievement. Additionally, both academic self-efficacy building feedback and self-monitoring prompts demonstrated modest effects on achievement. Results are discussed relative to SRL theory, classroom application, and Web-based instructional design.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Hidden expectations: Scaffolding subject specialists' genre knowledge of the assignments they set

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    Subject specialists’ knowledge of academic and disciplinary literacy is often tacit. We tackle the issue of how to elicit subject specialists’ tacit knowledge in order to develop their pedagogical practices and enable them to communicate this knowledge to students. Drawing on theories of genre and metacognition, a professional development activity was designed and delivered. Our aims were to (1) build participants’ genre knowledge and (2) scaffold metacognitive awareness of how genre knowledge can enhance their pedagogical practices. The findings reveal that participants built a genre-based understanding of academic literacy and that the tasks provided them with an accessible framework to articulate and reflect upon their knowledge of disciplinary literacy. Participants gained metacognitive awareness of misalignments between what they teach and what they expect from students, their assumptions about students’ prior learning and genre-based strategies to adapt their practice to students’ needs. Our approach provides a theoretically grounded professional development tool for the HE sector

    Relationships between students' conceptions of constructivist learning and their regulation and processing strategies

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    The present study investigated relationships between students' conceptions of constructivist learning on the one hand, and their regulation and processing strategies on the other hand. Students in a constructivist, problem-based learning curriculum were questioned about their conceptions of knowledge construction and self-regulated learning, as well as their beliefs regarding their own (in)ability to learn and motivation to learn. Two hypothesized models were tested within 98 psychology students, using a structural equation modelling approach: The first model implemented regulation and processing variables of the Inventory of Learning Styles [ILS, Vermunt (Learning styles and regulation of learning in higher education - towards process-oriented instruction in autonomous thinking, 1992)], the second model of the Motivated Strategies for Learning Questionnaire [MSLQ, Pintrich and de Groot (Journal of Educational Psychology, 82, 33-40, 1990)]. Results showed that structural relations exist between conceptions of constructivist learning and regulation and processing strategies. Furthermore, students who express doubt with regard to their own learning capacities are at risk for adopting an inadequate regulation strategy. A three-tiered structure of conceptual, controlling, and operational level appeared valid for the MSLQ variables, but not entirely for those of the ILS

    Cognitive engagement in the problem-based learning classroom

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    The objective of the present study was to examine to what extent autonomy in problem-based learning (PBL) results in cognitive engagement with the topic at hand. To that end, a short self-report instrument was devised and validated. Moreover, it was examined how cognitive engagement develops as a function of the learning process and the extent to which cognitive engagement determines subsequent levels of cognitive engagement during a one-day PBL event. Data were analyzed by means of confirmatory factor analysis, repeated measures ANOVA, and path analysis. The results showed that the new measure of situational cognitive engagement is valid and reliable. Furthermore, the results revealed that students’ cognitive engagement significantly increased as a function of the learning event. Implications of these findings for PBL are discussed
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