[Development and correlation of work-related behavior and experience patterns, burnout and quality of life in medical students from their freshmanship to the first state examination]. / Entwicklung und Zusammenhang von Arbeitsverhalten, Burnout-Beschwerden und Lebensqualität bei Studierenden der Humanmedizin vom Studienstart bis zum ersten Staatsexamen.

Symptoms of burnout are common among medical students. Although they usually start with a good health status, their condition deteriorates over the course of their studies. In our study ESTRELLAS we examined 530 medical students in the preclinical semesters with validated psychological questionnaires. The longer the students were studying, the more showed risky working habits. Cognitive and emotional burnout symptoms increased coincidentally in their intensity, whereas the mental quality of life continuously deteriorated. Medical students' cognitive and emotional burnout symptoms are constantly increasing from the beginning of their studies. Contemporaneously, the mental quality of life is deteriorating. This might be based on a drastic change towards risky working habits. We suggest to actively work against this process to keep our motivated students and prospective physicians productive and in good mental health.

Effect of intermittent shear stress on corneal epithelial cells using an in vitro flow culture model.

PURPOSE: The aim of this study was to establish and to evaluate an in vitro model for culturing human telomerase-immortalized corneal epithelial (hTCEpi) cells under adjustable medium flow mimicking the movements of the tear film on the ocular surface. METHODS: Using an IBIDI pump system, cells were cultured under unidirectional, continuous or oscillating, discontinuous medium flow. Cell surface and cytoskeletal architecture were investigated by scanning electron microscopy and immunofluorescence. Gene expression of e-cadherin, occludin, tight junction protein (TJP), desmoplakin, desmocollin and mucins was investigated by real-time PCR. Protein expression of desmoplakin, TJP, occludin and e-cadherin was analyzed by western blot and localization was detected by immunofluorescence. Rose bengal staining was used to assess mucin (MUC) barrier integrity. MUC1, -4 and -16 proteins were localized by immunofluorescence. RESULTS: Medium flow-induced shear stress dramatically changed cellular morphology of hTCEpi. Cells subjected to discontinuous shear stress displayed the typical flattened, polygonal cell shape of the superficial layer of stratified squamous epithelia. Cell surfaces showed less bulging under shear stress and less extracellular gaps. The mRNA expression of E-cadherin, occludin and TJP were increased under oscillatory medium flow. Desmoplakin and occludin protein were upregulated under oscillatory shear stress. Stress fiber formation was not aligned to flow direction. MUC1, -4, and -16 protein were localized under all culture conditions, a regulation on mRNA expression was not detectable. Rose Bengal uptake was diminished under unidirectional conditions. CONCLUSION: Our findings suggest that shear stress as it occurs at the ocular surface during blinking exerts marked effects on corneal epithelial cells, such as changes in cellular morphology and expression of cell junctions. The described model may be useful for in vitro investigations of ocular surface epithelia as it represents a much more physiologic reproduction of the in vivo situation than the commonly applied static culture conditions.