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Platelets are central players in thrombosis and hemostasis but are increasingly recognized as key components of the immune system. They shape ensuing immune responses by recruiting leukocytes, and support the development of adaptive immunity. Recent data shed new light on the complex role of platelets in immunity. Here, we summarize experimental and clinical data on the role of platelets in host defense against bacteria. Platelets bind, contain, and kill bacteria directly; however, platelet proinflammatory effector functions and cross-talk with the coagulation system, can also result in damage to the host (e.g., acute lung injury and sepsis). Novel clinical insights support this dichotomy: platelet inhibition/thrombocytopenia can be either harmful or protective, depending on pathophysiological context. Clinical studies are currently addressing this aspect in greater depth., (Copyright © 2019. Published by Elsevier Ltd.)

The three-dimensional structure of GaN/(In,Ga)N core-shell nanowires with multi-faceted pencil-shaped apex is analyzed by electron tomography using high-angle annular dark-field mode in a scanning transmission electron microscope. Selective area growth on GaN-on-sapphire templates using a patterned mask is performed by molecular beam epitaxy to obtain ordered arrays of uniform nanowires. Our results of the tomographic reconstruction allow the detailed determination of the complex morphology of the inner (In,Ga)N multi-faceted shell structure and its deviation from the perfect hexagonal symmetry. The tomogram unambiguously identifies a dot-in-a-wire configuration at the nanowire apex including the exact shape and size, as well as the spatial distribution of its chemical composition.

Aneurysm is a multifactorial degenerative disease characterized by focal dilatation of blood vessels. Although abdominal aortic (AAA) and popliteal aneurysms (PAA) are the most common dilatative vascular diseases and share some features, a comparison between the different anatomical sites and the relative pathophysiological differences has not been established. In order to gain deeper insights to AAA and PAA, we have characterized the role of matrix remodelling, vascular cells phenotype depletion and the inflammatory process in both diseases. Results show a more extensive presence of T-cell, B-cell and monocyte-macrophage infiltration in AAA with respect to PAA. Concurring with this aspect, IL-6, IL-8 and MCP-1 are 10-fold increased in AAA. Moreover, MMP-9, and metalloproteinase inhibitor 3 (TIMP3) resulted up-regulated in AAA tissues. Regarding the catalytic activity, which is tightly related to the oxidative stress, we found an up-regulation of superoxide dismutase [Mn] mitochondrial (SODM), glutathione peroxidase 3 (GPX3) and peroxiredoxin-1 (PRDX1). Histological analyses clearly showed a massive elastin fragmentation in AAA. This may enhance the inflammatory response, which has a prevalent role in AAA, while PAA is mainly guided by a loss of the contractile phenotype. These findings suggest insight in these potentially devastating diseases in term of their progression, aiming to identify potential specific markers respectively for AAA and PAA treatment., Competing Interests: None.

Background: Social networking sites, in particular Facebook, are not only predominant in students' social life but are to varying degrees interwoven with the medical curriculum. Particularly, Facebook groups have been identified for their potential in higher education. However, there is a paucity of data on user types, content, and dynamics of study-related Facebook groups., Objective: The aim of this study was to identify the role of study-related Facebook group use, characterize medical students that use or avoid using Facebook groups (demographics, participation pattern, and motivation), and analyze student posting behavior, covered topics, dynamics, and limitations in Facebook groups with regards to educational usage., Methods: Using a multi-method approach (interviews, focus groups, and qualitative and quantitative analysis of Facebook posts), we analyzed two representative Facebook groups of medical preclinical semesters at Ludwig-Maximilians-University (LMU) Munich. Facebook primary posts and replies over one semester were extracted and evaluated by using thematic content analysis. We developed and applied a coding scheme for studying the frequency and distribution of these posts. Additionally, we interviewed students with various degrees of involvement in the groups, as well as "new minorities," students not registered on Facebook., Results: Facebook groups seem to have evolved as the main tool for medical students at LMU to complement the curriculum and to discuss study-related content. These Facebook groups are self-organizing and quickly adapt to organizational or subject-related challenges posed by the curriculum. A wide range of topics is covered, with a dominance of organization-related posts (58.35% [6916/11,853] of overall posts). By measuring reply rates and comments per category, we were able to identify learning tips and strategies, material sharing, and course content discussions as the most relevant categories. Rates of adequate replies in these categories ranged between 78% (11/14) and 100% (13/13), and the number of comments per post ranged from 8.4 to 13.7 compared with the average overall reply rate of 68.69% (1167/1699) and 3.9 comments per post. User typology revealed social media drivers (>30 posts per semester) as engines of group function, frequent users (11-30 posts), and a majority of average users acting rather as consumers or lurkers (1-10 posts)., Conclusions: For the moment, the medical faculty has no active involvement in these groups and therefore no influence on accuracy of information, professionalism, and ethical issues. Nevertheless, faculty could in the future benefit by extracting relevant information, identifying common problems, and understanding semester-related dynamics., (©Leo Nicolai, Moritz Schmidbauer, Maximilian Gradel, Sabine Ferch, Sofía Antón, Boj Hoppe, Tanja Pander, Philip von der Borch, Severin Pinilla, Martin Fischer, Konstantinos Dimitriadis. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 22.12.2017.)

Blood platelets are critical for hemostasis and thrombosis and play diverse roles during immune responses. Despite these versatile tasks in mammalian biology, their skills on a cellular level are deemed limited, mainly consisting in rolling, adhesion, and aggregate formation. Here, we identify an unappreciated asset of platelets and show that adherent platelets use adhesion receptors to mechanically probe the adhesive substrate in their local microenvironment. When actomyosin-dependent traction forces overcome substrate resistance, platelets migrate and pile up the adhesive substrate together with any bound particulate material. They use this ability to act as cellular scavengers, scanning the vascular surface for potential invaders and collecting deposited bacteria. Microbe collection by migrating platelets boosts the activity of professional phagocytes, exacerbating inflammatory tissue injury in sepsis. This assigns platelets a central role in innate immune responses and identifies them as potential targets to dampen inflammatory tissue damage in clinical scenarios of severe systemic infection., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Introduction: One of the most important extracurricular aspects of medical studies in Germany is a research thesis completed by most students. This research project often times conveys relevant competencies for the physician's role as scientist. Nevertheless, the choice of the right project remains a challenge. Reasons for this are among others, missing structures for a comprehensive overview of research groups and their respective projects. Description of the project: We developed the online platform Doktabörse as an online marketplace for doctoral research projects. The platform enables authorized researchers to create working groups and upload, deactivate and change research projects within their institute. For interested students, a front end with integrated search function displays these projects in a structured and well-arranged way. In parallel, the Doktabörse provides for a comprehensive overview of research at the medical faculty. We evaluated Researchers' and students' use of the platform. Results: 96,6% of students participating in the evaluation (n=400) were in favor of a centralized research platform at the medical faculty. The platform grew at a steady pace and included 120 research groups in June 2016. The students appreciated the structure and design of the Doktabörse. Two thirds of all uploaded projects matched successfully with doctoral students via the platform and over 94% of researchers stated that they did not need technical assistance with uploading projects and handling the platform. Discussion : The Doktabörse represents an innovative and well accepted platform for doctoral research projects. The platform is perceived positively by researchers and students alike. However, students criticized limited extent and timeliness of offered projects. In addition, the platform serves as databank of research at the medical faculty of the LMU Munich. The future potential of this platform is to provide for an integrated management solution of doctoral thesis projects, possibly beyond the medical field and faculty.

Introduction: During their formal studies medical students acquire extensive medical expertise. However, the medical profession demands additional competencies, such as those involved in efficient resource allocation, business administration, development, organization, and process management in the healthcare system. At present students are not sufficiently prepared for the physician's role as manager. In response, we designed the seminar course, MeCuM-SiGma, to impart basic knowledge about healthcare policy and management to students of medicine. This project report describes our teaching strategies and the initial evaluation of this educational project., Project Description: In this semester-long, seminar course introduced in 2010, medical students gather experience with the competencies mentioned above as well as learn basic management skills. The course is offered each winter semester, and students sign up to attend voluntarily; course coordination and organization is done on a voluntary basis by physicians and employees of the Mentoring Office (MeCuM-Mentor) at the Medical School of the Ludwig Maximilian University (LMU) in Munich, Germany. The course is open to all students enrolled at the two medical schools in Munich. During the first part of this elective, students learn about the basic principles of the German political and healthcare systems in case-based, problem-based tutorials led by trained tutors and in lectures held by experts. In the second part of the course students take on the roles of the University Hospital's executive board of directors and supervisory board to work on an existing hospital project as a group within the scope of a simulation. This phase of the course is accompanied by workshops conducted in cooperation with university-based and off-campus partners that address the procedural learning objectives (teamwork, project management, negotiation strategies, etc.). A suitable, authentic issue currently facing the hospital is selected in advance by the course organizers in coordination with the hospital's executive board. Students then work on this issue in the third and final phase of the course under the supervision of tutors and with assistance from hospital employees. At the end of the course the students formally present the results of their work to the hospital's executive and supervisory boards., Results: The course undergoes written student evaluation, a round of oral feedback, evaluation of the final projects, and feedback from the hospital's executive and supervisory boards. All attendees to date have reported a substantial gain in general knowledge and increased knowledge about the healthcare system, and rate the relevance of the course as being high. The majority felt the content was important for their future practice of medicine. Overall, students evaluated the course very positively [overall rating on a six-point grading scale (1=excellent; 6=unsatisfactory): 1.28 (mean)±0.45 (standard deviation)]., Discussion: The importance of the physician's role as manager in medical organizations and as a guiding force in the healthcare system is neglected in medical degree programs. Our seminar course attempts to address this shortcoming, is the object of great interest and receives positive evaluations from seminar participants, our cooperative partners and the executive and supervisory boards of the University Hospital in Munich.

Background: Peer mentoring is a powerful pedagogical approach for supporting undergraduate medical students in their learning environment. However, it remains unclear what exactly peer mentoring is and whether and how undergraduate medical students use social media for peer-mentoring activities., Objective: We aimed at describing and exploring the Facebook use of undergraduate medical students during their first 2 years at a German medical school. The data should help medical educators to effectively integrate social media in formal mentoring programs for medical students., Methods: We developed a coding scheme for peer mentoring and conducted a mixed-methods study in order to explore Facebook groups of undergraduate medical students from a peer-mentoring perspective., Results: All major peer-mentoring categories were identified in Facebook groups of medical students. The relevance of these Facebook groups was confirmed through triangulation with focus groups and descriptive statistics. Medical students made extensive use of Facebook and wrote a total of 11,853 posts and comments in the respective Facebook groups (n=2362 total group members). Posting peaks were identified at the beginning of semesters and before exam periods, reflecting the formal curriculum milestones., Conclusions: Peer mentoring is present in Facebook groups formed by undergraduate medical students who extensively use these groups to seek advice from peers on study-related issues and, in particular, exam preparation. These groups also seem to be effective in supporting responsive and large-scale peer-mentoring structures; formal mentoring programs might benefit from integrating social media into their activity portfolio., Competing Interests: Conflicts of Interest: None declared.

Purpose: The objective of this study is to quantify the influence of linear motion, calcification density, and temporal resolution on coronary calcium determination using multidetector computed tomography (MDCT), dual source CT (DSCT), and electron beam tomography (EBT) and to find a quantitative method which corrects for the influences of these parameters using a linear moving cardiac phantom., Methods: On a robotic arm with artificial arteries with four calcifications of increasing density, a linear movement was applied between 0 and 120 mm/s (step of 10 mm/s). The phantom was scanned five times on 64-slice MDCT, DSCT, and EBT using a standard acquisition protocol. The average Agatston, volume, and mass scores were determined for each velocity, calcification, and scanner. Susceptibility to motion was quantified using a cardiac motion susceptibility (CMS) index. Resemblance to EBT and physical volume and mass was quantified using a Delta index., Results: Increasing motion artifacts were observed at increasing velocities on all scanners, with increasing severity from EBT to DSCT to 64-slice MDCT. The calcium score showed a linear dependency on motion from which a correction factor could be derived. This correction factor showed a linear dependency on the mean calcification density with a good fit for all three scoring methods and all three scanners (0.73 < or = R2 < or = 0.95). The slope and offset of this correction factor showed a linear dependency on temporal resolution with a good fit for all three scoring methods and all three scanners (0.83 < or = R2 < or = 0.98). CMS was minimal for EBT and increasing values were observed for DSCT and highest values for 64-slice MDCT. CMS was minimal for mass score and increasing values were observed for volume score and highest values for Agatston score. For all densities and scoring methods DSCT showed on average the closest resemblance to EBT calcium scores. When using the correction factor, CMS index decreased on average by 15% and Delta index decreased by 35%., Conclusions: Calcium scores determined on DSCT and 64-slice MDCT are highly susceptible to motion as compared to EBT. The mass score is less susceptible to motion compared to volume and Agatston score. Calcium scores determined on DSCT bear a closer resemblance to EBT obtained calcium scores than 64-slice MDCT. In addition, the calcium score is highly dependent on the average density of individual calcifications and the dependency of the calcium score on motion showed a linear behavior on calcification density. From these relations, a quantitative method could be derived which corrects the measured calcium score for the influence of linear motion, mean calcification density, and temporal resolution.

Following the clinical diagnosis of the first case of mumps on September 22, 2006 at the University of Virginia (UVA), 52 suspected cases were identified through active surveillance for mumps by the end of December 2006. Samples were collected from 47 students who presented with parotitis despite a documented history of two doses of measles, mumps, and rubella (MMR) vaccine. Six of 47 serum samples (13%) were positive for mumps IgM, and 46/47 specimens were positive for mumps IgG. Endpoint titration of acute phase serum samples from laboratory-confirmed cases did not provide evidence that elevated serum IgG is a consistent marker for infection among cases due to secondary vaccine failure. Buccal swab samples from 39 of the 47 students were tested by real-time reverse transcription-polymerase chain reaction (RT-PCR) and/or viral culture. Mumps virus or mumps RNA was detected in 12 of 39 buccal samples (31%). Genetic analysis of the virus from the outbreak at UVA indicated that the outbreak was not linked to the large mumps outbreak in the Midwestern US that occurred earlier in 2006. Our findings support the use of viral detection to improve laboratory diagnosis of mumps among persons who have received two doses of MMR.