As platelet activation is closely related to the liberation of growth factors and inflammatory mediators, platelets play a central role in the development of CVD. Virtually all cardiovascular risk factors favor platelet hyperreactivity and, accordingly, also physical (in)activity affects platelet function. Within this paper, we will summarize and discuss the current knowledge on the impact of acute and habitual exercise on platelet function. Although there are apparent discrepancies regarding the reported effects of acute, strenuous exercise on platelet activation, a deeper analysis of the available literature reveals that the applied exercise intensity and the subjects’ cardiorespiratory fitness represent critical determinants for the observed effects. Consideration of these factors leads to the summary that (i) acute, strenuous exercise can lead to platelet activation, (ii) regular physical activity and/or physical fitness diminish or prevent platelet activation in response to acute exercise, and (iii) habitual physical activity and/or physical fitness also favorably modulate platelet function at physical rest. Notably, these effects of exercise on platelet function show obvious similarities to the well-recognized relation between exercise and the risk for cardiovascular events where vigorous exercise transiently increases the risk for myocardial infarction and a physically active lifestyle dramatically reduces cardiovascular mortality.
Platelets and lipoproteins play a crucial role in atherogenesis, in part by their ability to modulate inflammation and oxidative stress. While oxidized low density lipoproteins (OxLDL) play a central role in the development of this disease, high density lipoproteins (HDL) represent an atheroprotective factor of utmost importance. As platelet function is remarkably sensitive to the influence of plasma lipoproteins, it was the aim of this study to clarify if HDL are able to counteract the stimulating effects of OxLDL with special emphasis on aspects of platelet function that are relevant to inflammation. Therefore, HDL were tested for their ability to interfere with pro-thrombotic and pro-inflammatory aspects of platelet function. We are able to show that HDL significantly impaired OxLDL-induced platelet aggregation and adhesion. In gel-filtered platelets, HDL decreased both the formation of reactive oxygen species and CD40L expression. Furthermore, HDL strongly interfered with OxLDL-induced formation of platelet-neutrophil aggregates in whole blood, suggesting that platelets represent a relevant and sensitive target for HDL. The finding that HDL effectively competed with the binding of OxLDL to the platelet surface might contribute to their atheroprotective and antithrombotic properties.
Background: The mere memorization of isolated facts without the claim of integrating them is detrimental to the desired learning outcomes in medical education. The current study was conducted within an environment where items from summative assessments are regularly disclosed by the university and consequently collected into an item bank that is shared between students. Within this environment, we aimed to quantify 1) to which extent students use disclosed items for their preparation for the summative exam, 2) a putative mismatch between (isolated factual) knowledge regarding distinct questions from the item bank and conceptual knowledge, and 3) to which extent this mismatch can be ameliorated by a project aiming to steer student learning away from the memorization of isolated facts toward the acquisition of conceptual knowledge.Methods: This steering project in the midst of the first semester consisted of the implementation of an oral exam based on selected learning objectives, preceded by two seminars. After their summative exam at the end of semester, 135 students performed a voluntary exam for study purposes. Here, authentic (i.e., presumably preknown) physiology questions taken from the item bank were used to assess students’ ability to 1) recognize the correct answer in a multiple choice (MC) question, 2) recall the answer (short answer), or 3) display conceptual knowledge closely corresponding to the question presented in the other formats. Additionally, students received a questionnaire addressing their learning habits and attitudes.Results: The median reported percentage of learning time for the summative exam exclusively spent with this item bank was 80%. The results of the voluntary exam indicate that students frequently recognize and recall correct answers of included items without displaying knowledge of the underlying concept. Compared to recall of the correct answer, the probability of giving a correct answer regarding the corresponding basal physiologic concept was lower by 47 percentage points (p <0.001) for topics not included in the steering project. Regarding topics included in the steering project, this discrepancy was reduced to 25.5% (p <0.001).Conclusion: The results of this study demonstrate the influence of disclosed items on student learning and learning outcomes and suggest that a carefully implemented assessment is able to improve conceptual knowledge in physiology.
In team-based learning, students are typically placed in fixed teams based on the idea that stable group membership fosters collaboration: as teammates get to know each other, they share more information, resolve differences and feel motivated to contribute. This rationale had not been tested in a randomized controlled trial. The study compares team-based learning in temporary teams with the default permanent teams regarding individual and team readiness assurance test performance (iRAT, tRAT), reaching team consensus, the learning climate, and intrinsic motivation. In a randomized controlled trial, first-year medical students were assigned either to permanent TBL teams or to teams that were re-assigned for each problem. The team readiness assurance test (tRAT) votes, submitted individually and covertly, served as an indirect indicator for team consensus (concordant versus discordant tRAT vote). Discordant tRATs (n = 268, 11.8% of all votes) were submitted more frequently in temporary than in permanent teams, both for correct and incorrect majority decisions. The self-rated learning climate was more cooperative in permanent than in temporary teams, while intrinsic motivation and tRAT scores were similar for both types of teams. A poorer learning climate was associated with a higher proportion of discordant tRATs. Working in temporary teams does not lead to inferior intrinsic motivation; this was previously also shown for knowledge gain. However, the poorer learning climate, together with reaching a consensus less often, might indicate that at least some members of temporary teams feel not adequately appreciated in the discussion and do not accept the majority decision. With instructional strategies promoting a cooperative learning climate in temporary teams, preclinical TBL courses might serve as an early promoter of the relational team competencies required for subsequent clinical workplace learning in temporary teams.
Objective: Replacing face-to-face lessons by remote teaching due to COVID-19 led to a markedly reduced interaction between students and lecturers. In our opinion, one of the main reasons for this is the raise hand function of the respective web conference systems, which (independent of the system used) results in an unobtrusive signal that can easily be missed by the lecturer. Given the necessary focus on one's own presentation, questions can therefore only be perceived with a considerable time delay and can only be integrated into the lessons to a limited extent. Thus, the idea arose to display question requests of the auditorium by a clear visual signal in PowerPoint (R) itself. Methodology: With Visual Basic for Applications (VBA), Microsoft PowerPoint (R) holds an integrated programming language that extends its functionality. Accordingly, VBA was used to program a routine running in the background of the presentation, which periodically retrieves the contents of a web-based "signal file" in a cycle of a few seconds. The content of this signal file, in turn, can be modified by the students by calling up an URL (i.e. from any Internet-capable device) - this results in a (customizable) visual signal in PowerPoint (R) that is temporarily visible and does not further interfere with the presentation. Conclusion: With the concept presented here, a raise hand function was realized in PowerPoint (R), which manifests itself as a clear visual signal independent of the web conferencing system used. This enables the lecturers to respond instantly to questions from the audience during live transmission of lectures.
Objective: The aim of this project was to convert a traditional face-to-face seminar for the teaching of experimental scientific methodology to remote teaching in a timely manner due to the COVID-19 related restrictions to teaching in presence. Methodology: The main focus of the course was on flow cytometry. Basics were developed in a virtual presence phase. Specific teaching contents were taught by an interactive presentation, which came very close to the user experience of a flow cytometer and interactively illustrated the influence of different experimental conditions on the obtained results. Video sequences of authentic sample acquisitions were integrated into Adobe Captivate (R). These "virtual acquisitions" were not distinguishable from the original procedure. For interpretation of the resulting diagrams, interactions were inserted, which allowed direct comparison of the obtained results. Implementation: A presentation with interactive elements and video sequences was created and used for the virtual presence phases. After publishing on a web server in HTML 5, contents were made available to the students for post-processing of learning contents by self-paced learning with full (interactive) functionality. Conclusion: Contributions elaborated by the students during the course demonstrate a learning outcome comparable to that archieved in the last years in presence mode. While implementation of this solution represented a highly time-consuming process, narrative feedback was consistently positive. Due to the short time available for implementation, no systematic evaluation could be conducted, which represents a clear limitation of this work.