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.

Hypoxia increases membrane metallo-endopeptidase expression in a novel lung cancer ex vivo model - role of tumor stroma cells

Background: Hypoxia-induced genes are potential targets in cancer therapy. Responses to hypoxia have been extensively studied in vitro, however, they may differ in vivo due to the specific tumor microenvironment. In this study gene expression profiles were obtained from fresh human lung cancer tissue fragments cultured ex vivo under different oxygen concentrations in order to study responses to hypoxia in a model that mimics human lung cancer in vivo.Methods: Non-small cell lung cancer (NSCLC) fragments from altogether 70 patients were maintained ex vivo in normoxia or hypoxia in short-term culture. Viability, apoptosis rates and tissue hypoxia were assessed. Gene expression profiles were studied using Affymetrix GeneChip 1.0 ST microarrays.Results: Apoptosis rates were comparable in normoxia and hypoxia despite different oxygenation levels, suggesting adaptation of tumor cells to hypoxia. Gene expression profiles in hypoxic compared to normoxic fragments largely overlapped with published hypoxia-signatures. While most of these genes were up-regulated by hypoxia also in NSCLC cell lines, membrane metallo-endopeptidase (MME, neprilysin, CD10) expression was not increased in hypoxia in NSCLC cell lines, but in carcinoma-associated fibroblasts isolated from non-small cell lung cancers. High MME expression was significantly associated with poor overall survival in 342 NSCLC patients in a meta-analysis of published microarray datasets.Conclusions: The novel ex vivo model allowed for the first time to analyze hypoxia-regulated gene expression in preserved human lung cancer tissue. Gene expression profiles in human hypoxic lung cancer tissue overlapped with hypoxia-signatures from cancer cell lines, however, the elastase MME was identified as a novel hypoxia-induced gene in lung cancer. Due to the lack of hypoxia effects on MME expression in NSCLC cell lines in contrast to carcinoma-associated fibroblasts, a direct up-regulation of stroma fibroblast MME expression under hypoxia might contribute to enhanced aggressiveness of hypoxic cancers