Educational Measurement im medizinischen eLearning. Begleitende Effektivitätsmessung im Rahmen freier Wahlfächer

An der Medizinischen Universität Graz wird eLearning in großem Umfang genutzt, was durch Zugriffszahlen von mehr als 300.000 pro Monat dokumentiert ist. Als entscheidendes Qualitätskriterium erachtet die Universität die Lerneffektivität der eLearning-Angebote. Die Einrichtung freier Wahlfächer zum medizinischen Lernen mit Neuen Medien erlaubt die Durchführung experimentell-didaktischer Studien an konkretem Unterrichtsmaterial mit Studierenden, die sich aus der realen Zielgruppe rekrutieren. Bisher wurden Studien zur Generierung expliziten Wissens durch Computer-Based Training, die Effektivität von Case-Based Reasoning, den Einfluss variabler gegenüber wiederholter Fälle, die Auswirkungen von Drill-and-Practice, die Kombination systematischer Einführungen in Ergänzung zu fallbasierten Formaten sowie der didaktische Wert ergänzenden Bildmaterials, virtueller mikroskopischer Präparate und komplexer Simulationen untersucht. Im Aufbau ist die partizipatorische eLearning-Gestaltung durch die Studierenden und problembasiertes Lernen durch kooperatives Arbeiten im Netz. Die gewonnenen quantitativen Erkenntnisse werden unmittelbar im Alltag der eLearning-Entwicklung umgesetzt. (DIPF/Orig.

Aufbau eines universitätsweiten Lerninformationssystems parallel zur Entwicklung innovativer Curricula- zeitliche Entwicklung und Synergieeffekte

An der Medizinischen Universität Graz wurde parallel zum Aufbau eines integrativen, fächerübergreifenden Curriculums ein Lerninformationssystem zur direkten Abbildung der Lerninhalte im virtuellen Raum entwickelt. Dabei wurde die Schwelle für die Lehrenden zum Einstellen von Lerninhalten niedrig gehalten, sowohl was die technischen Voraussetzungen als auch die qualitativen Anforderungen betrifft. Innerhalb von nicht ganz drei Jahren wurden mehr als 2000 Lernobjekte aufgenommen und pro Monat bis zu 40.000 Zugriffe durch die Studierenden auf die Lernobjekte registriert. Die synchrone Entwicklung des neuen Curriculums zusammen mit den elektronischen Medien zeigte wechselseitige Synergien, insbesondere in Hinblick auf eine erhöhte Transparenz für die Lehrenden und eine bessere Orientierung für die Studierenden. Als Nachteil stellte sich in der Anfangsphase das Überwiegen von Präsentations- und Visualisierungsobjekten heraus. Dem wird durch die Entwicklung von Autorenwerkzeugen für interaktive Lernobjekte und die Unterstützung der Gestaltung von Animationen und Simulationen entgegengewirkt. Die aktuellen Weiterentwicklungen umfassen Mehrstudienfähigkeit und Mehrsprachigkeit, den Ersatz eines Teils der Lehrveranstaltungen durch rein virtuelle Angebote, den Aufbau internationaler Kooperationen und die Integration kollaborativer Arbeitssysteme. (DIPF/Orig.

Thoracic wall reconstruction using both portions of the latissimus dorsi previously divided in the course of posterolateral thoracotomy

Objective: Besides other factors, the choice of reconstructive method for full thickness thoracic wall defects depends on the morbidity of preceding surgical procedures. The pedicled latissimus dorsi flap is a reliable and safe option for reconstruction of the thorax. A posterolateral thoracotomy, however, results in division of the muscle. Both parts of the muscle can be employed to close full thickness defects of the chest wall. The proximal part can be pedicled on the thoracodorsal vessels or the serratus branch; the distal part can be pedicled on paravertebral or intercostal perforators. This retrospective study was undertaken to evaluate the reconstructive potential of both parts of the latissimus dorsi in thoracic wall reconstruction after posterolateral thoracotomy. Methods: Between 1987 and 1999, 36 consecutive patients underwent reconstruction of full-thickness thoracic wall defects with latissimus dorsi-flaps after posterolateral thoracotomies. The defects resulted from infection and open window thoracostomy (n=31), trauma (n=3) and resection of tumours (n=2). The patients' average age was 57 years (range 22-76 years). Twenty-five patients were male, 11 were female. In 31 cases the split latissimus dorsi alone was employed; in five cases additional flaps had to be used due to the size of the defects, additional intrathoracic problems or neighbouring defects. Results: In 34 cases defect closure could be achieved without major complications. Empyema recurred in the pleural cavity in one case and one patient died of septicaemia. The 15 patients who had required a respirator in the preoperative phase could be extubated 4.8 days (average) after thoracic wall reconstruction. Postoperative hospital stay averaged 16 days. Conclusions: Different methods are available for reconstruction of full thickness defects of the thoracic wall. After posterolateral thoracotomy in the surgical treatment of empyema, oncologic surgery and traumatology, the latissimus dorsi muscle still retains some reconstructive potential. Advantages are low additional donor site morbidity and anatomical reliability. As it is located near the site of the defect, there is no need for additional surgical sites or intraoperative repositioning. In our service, the split latissimus dorsi muscle flap has proven to be a valuable and reliable option in thoracic wall reconstructio

Variation in the organization and subunit composition of the mammalian pyruvate dehydrogenase complex E2/E3BP core assembly

The final version of this article is available at the link below.Crucial to glucose homoeostasis in humans, the hPDC (human pyruvate dehydrogenase complex) is a massive molecular machine comprising multiple copies of three distinct enzymes (E1–E3) and an accessory subunit, E3BP (E3-binding protein). Its icosahedral E2/E3BP 60-meric ‘core’ provides the central structural and mechanistic framework ensuring favourable E1 and E3 positioning and enzyme co-operativity. Current core models indicate either a 48E2+12E3BP or a 40E2+20E3BP subunit composition. In the present study, we demonstrate clear differences in subunit content and organization between the recombinant hPDC core (rhPDC; 40E2+20E3BP), generated under defined conditions where E3BP is produced in excess, and its native bovine (48E2+12E3BP) counterpart. The results of the present study provide a rational basis for resolving apparent differences between previous models, both obtained using rhE2/E3BP core assemblies where no account was taken of relative E2 and E3BP expression levels. Mathematical modelling predicts that an ‘average’ 48E2+12E3BP core arrangement allows maximum flexibility in assembly, while providing the appropriate balance of bound E1 and E3 enzymes for optimal catalytic efficiency and regulatory fine-tuning. We also show that the rhE2/E3BP and bovine E2/E3BP cores bind E3s with a 2:1 stoichiometry, and propose that mammalian PDC comprises a heterogeneous population of assemblies incorporating a network of E3 (and possibly E1) cross-bridges above the core surface.This work was partly supported by EPSRC (under grants GR/R99393/01 and EP/C015452/1)

Lysosome-mediated processing of chromatin in senescence

Cellular senescence is a stable proliferation arrest, a potent tumor suppressor mechanism, and a likely contributor to tissue aging. Cellular senescence involves extensive cellular remodeling, including of chromatin structure. Autophagy and lysosomes are important for recycling of cellular constituents and cell remodeling. Here we show that an autophagy/lysosomal pathway processes chromatin in senescent cells. In senescent cells, lamin A/C–negative, but strongly γ-H2AX–positive and H3K27me3-positive, cytoplasmic chromatin fragments (CCFs) budded off nuclei, and this was associated with lamin B1 down-regulation and the loss of nuclear envelope integrity. In the cytoplasm, CCFs were targeted by the autophagy machinery. Senescent cells exhibited markers of lysosomal-mediated proteolytic processing of histones and were progressively depleted of total histone content in a lysosome-dependent manner. In vivo, depletion of histones correlated with nevus maturation, an established histopathologic parameter associated with proliferation arrest and clinical benignancy. We conclude that senescent cells process their chromatin via an autophagy/lysosomal pathway and that this might contribute to stability of senescence and tumor suppression

A modelling approach towards Epidermal homoeostasis control

In order to grasp the features arising from cellular discreteness and individuality, in large parts of cell tissue modelling agent-based models are favoured. The subclass of off-lattice models allows for a physical motivation of the intercellular interaction rules. We apply an improved version of a previously introduced off-lattice agent-based model to the steady-state flow equilibrium of skin. The dynamics of cells is determined by conservative and drag forces,supplemented with delta-correlated random forces. Cellular adjacency is detected by a weighted Delaunay triangulation. The cell cycle time of keratinocytes is controlled by a diffusible substance provided by the dermis. Its concentration is calculated from a diffusion equation with time-dependent boundary conditions and varying diffusion coefficients. The dynamics of a nutrient is also taken into account by a reaction-diffusion equation. It turns out that the analysed control mechanism suffices to explain several characteristics of epidermal homoeostasis formation. In addition, we examine the question of how {\em in silico} melanoma with decreased basal adhesion manage to persist within the steady-state flow-equilibrium of the skin.Interestingly, even for melanocyte cell cycle times being substantially shorter than for keratinocytes, tiny stochastic effects can lead to completely different outcomes. The results demonstrate that the understanding of initial states of tumour growth can profit significantly from the application of off-lattice agent-based models in computer simulations.Comment: 23 pages, 7 figures, 1 table; version that is to appear in Journal of Theoretical Biolog

Virtual medical campus: the increasing importance of E-learning in medical education

In 2002, along with the integration of a new, integrated curriculum in human medicine, the Virtual Medical Campus Graz was installed. It accompanies the whole curriculum with electronic materials tailored to the needs of the students and the forthcoming examinations. To date, more than 15,000 learning objects have been developed, and students download up to 200,000 learning objects per month. Particular emphasis is placed on Web-Based Training materials, but video and simulations are also included. In part, transfer of basic knowledge is mediated by electronic learning materials, replacing several hours of classroom attendance. Face-to-face education, in turn, is focusing increasingly on small-group clinical teaching

Liquid biopsy in non-small cell lung cancer: current status and future outlook—a narrative review

Lung cancer ranks first as the cause of cancer-associated deaths gobally. The American Cancer Society estimates for 228,820 new cases and 135,720 deaths from lung cancer in the United States for the year 2020. Targeted treatment options have rapidly emerged for non-small cell lung cancer (NSCLC) within the past decade. Screening for molecular aberrations is mainly done by tissue biopsy. However, in some cases a biopsy is not possible, or patients do not consent to it. Hence, liquid biopsy remains the only option. Relevant data about the topic of liquid biopsy, with a special focus on NSCLC, was obtained via a PubMed search. We included mainly literature published from 2010 onwards, omitting older studies whenever possible. With this review of the literature, we give an overview of different liquid biopsy approaches, as well as their respective advantages and disadvantages. We have reviewed the assessment of epidermal growth factor receptor (EGFR) mutation status in particular, and go into detail with current use of liquid biopsy in everyday clinical practice. Today, liquid biopsy is still infrequently used, depending on the treatment center, but popularity is steadily increasing. Various different approaches are already available, but costs and level of sensitivity significantly differ between techniques. By using liquid biopsy more widely in selected patients, complication rates can be reduced, and constant disease monitoring is made considerably easier