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Reinhard Friedl

Publications and source records attributed to Reinhard Friedl.

7 recordsLinked to original sources
PubMed2006

Multimedia-driven teaching significantly improves students' performance when compared with a print medium.

BACKGROUND: In this study, we compared the educational value of a multimedia module about aortic valve replacement as a preparation for the operating room with a print medium of identical content. METHODS: One hundred twenty-six students were randomly assigned in a prospective study to either use the multimedia course (n = 69) or a print version (n = 57). A 20-item multiple-choice test was performed before and after learning with the respective medium. Both groups participated in an operation during which they were evaluated with 28 standardized tasks and questions. Individual motivation, computer literacy, and didactic quality of both media were assessed with psychometric tests. RESULTS: There were no significant differences in the multiple-choice pretest (multimedia, 30.6% +/- 12.4% versus print, 27.9% +/- 11.4%) and posttest responses (multimedia, 76.7% +/- 13.3% versus print, 76.9% +/- 11.1). Mean percentage of correct answers during the operation was 82.9% +/- 10% in the online group and 64.7% +/- 12% in the print group (p < 0.0001). The multimedia group needed significantly (p < 0.001) less study time (105 +/- 24 minutes) when compared with the text group (122 +/- 30 minutes). There were no statistically significant differences in motivation, computer literacy, and didactic quality of either medium. CONCLUSIONS: Regarding factual knowledge, there is no difference between multimedia-driven learning and a print medium. During heart operations, when understanding of complex temporal and spatial events is essential, students' performance is significantly improved by multimedia-enhanced teaching. The latter further proved to be more efficient in terms of study time.

Adult↗
PubMed2006

Comparative evaluation of multimedia driven, interactive, and case-based teaching in heart surgery.

BACKGROUND: Multimedia-augmented instruction with various approaches is used in heart surgery. There is little evidence which instructional techniques and media are of advantage to impart knowledge more effectively and lead to better application of knowledge in the operation room. METHODS: Sixty-nine students learned with an interactive, case-based teaching (ICBT) course about aortic valve replacement. They were compared with historic controls exposed to identical information provided by a multimedia module presenting content systematically (SMM; n = 69) and a print medium (PM; n = 57). Motivation, computer knowledge, and didactic quality were evaluated with psychometric tests. All groups performed multiple choice pretests and posttests and participated in live surgery during which their performance was assessed. RESULTS: All groups had equal computer knowledge, but the ICBT group felt significantly less-motivated and more challenged. Multiple choice posttest results were comparable (ICBT 80.2% +/- 10.9%, SMM 76.7% +/- 13.3%, PM 76.9% +/- 11.1). During surgery, the ICBT (79.2% +/- 16%) and SMM groups (82.9% +/- 10%) performed significantly better than the PM group (64.7% +/- 12%; both p < 0.0001). Overall didactic assessment was significantly worse in the ICBT group when compared with the SMM and PM groups. CONCLUSIONS: For novices in heart surgery, ICBT was less motivating than traditionally structured content (SMM and PM). The ICBT did not improve performance in the operation room. However, both multimedia groups could better apply their knowledge during live surgery. The PM is as effective as multimedia when factual knowledge has to be retained.

Aortic Valve↗
PubMed2004

Intimal hyperplasia and expression of transforming growth factor-beta1 in saphenous veins and internal mammary arteries before coronary artery surgery.

BACKGROUND: The development of fibromuscular intimal hyperplasia and subsequent graft failure remains an urgent problem in cardiac surgery. Transforming growth factor-beta1 (TGF-beta1) is involved in the pathogenesis of arteriosclerosis through induction of extracellular matrix proteins. We tested the hypothesis that intimal hyperplasia is already present in human saphenous veins and left internal mammary arteries before coronary artery bypass surgery and is associated with an increased expression of TGF-beta1. METHODS: Forty-six segments of saphenous veins and 27 of left internal mammary arteries were collected from 50 patients undergoing coronary artery bypass surgery. Morphometric analysis was performed by microscopic computer analysis. Immunohistochemistry was performed with antibodies directed against TGF-beta1, its latent binding protein (LTBP-1) and its type 2 receptor (RII). RESULTS: The incidence of intimal hyperplasia was significantly higher in saphenous veins (67.4%) than in mammary arteries (29.6%; p < 0.05). Saphenous veins and mammary arteries with intimal hyperplasia expressed more TGF-beta1 (endothelial and intimal layers) and LTBP-1 (intimal and medial layers) when compared with corresponding vessels without hyperplasia (both groups p < 0.05). Endothelial and intimal RII expression was significantly higher in saphenous veins with intimal hyperplasia as compared with saphenous veins without hyperplasia (p < 0.05). Transforming growth factor-beta1 staining in the intima correlated with the presence of an intimal hyperplasia in saphenous veins (rho = 0.317) and mammary arteries (rho = 0.428). CONCLUSIONS: Local TGF-beta1 expression is associated with the presence of intimal hyperplasia in the examined vessels. Preexisting intimal hyperplasia is more prevalent and serious in saphenous veins than in left internal mammary arteries, giving further explanation to the superior long-term results of left internal mammary grafts.

Aged↗
PubMed2004

Thiazolidinediones reduce endothelial expression of receptors for advanced glycation end products.

Advanced glycation end products (AGEs) are critically involved in atherogenesis in diabetes by binding to receptors for AGE (RAGEs) in vascular cells, thus inducing the expression of proinflammatory mediators. In animal models, interruption of the AGE-RAGE interaction reduces lesion size and plaque development. Therefore, limiting RAGE expression might be an intriguing concept to modulate vascular disease in diabetic patients. The present study investigated whether thiazolidinediones (TZDs), antidiabetic agents clinically used to treat patients with type 2 diabetes, might modulate endothelial RAGE expression. Stimulation of human endothelial cells with rosiglitazone or pioglitazone decreased basal as well as tumor necrosis factor-alpha-induced RAGE cell surface and total protein expression. In addition, TZDs reduced RAGE mRNA expression in endothelial cells. These effects on RAGE expression were caused by an inhibition of nuclear factor-kappaB (NF-kappaB) activation at the proximal NF-kappaB site of the RAGE promoter. The functional relevance of reduced RAGE expression was demonstrated by showing that pretreatment of endothelial cells with TZDs decreased AGE- as well as beta-amyloid-induced monocyte chemoattractant protein-1 expression. In conclusion, TZDs reduce RAGE expression in human endothelial cells, thus limiting the cells' susceptibility toward proinflammatory AGE effects. These data provide new insight on how TZDs, in addition to their metabolic effects, might modulate the development of vascular dysfunction in diabetic patients.

Cells, Cultured↗
PubMed2002

Increased expression of TGF-beta1 and IGF-I in inflammatory stenotic lesions of hemodialysis fistulas.

BACKGROUND: Hemodialysis fistula dysfunction due to stenotic lesions remains a frequent cause of hospitalization for hemodialysis patients. Transforming growth factor-beta(TGF-beta) and insulin-like growth factor-I (IGF-I) are known to be involved in atherogenesis. The latent TGF-beta1 binding protein-1 (LTBP-1) targets extracellular matrix (ECM) interactions and is involved in the regulation of TGF-beta latency. METHODS: We investigated the expression of TGF-beta1, LTBP-1 and IGF-I in 15 occluded or severely narrowed vein segments of primary arteriovenous fistulas, in 29 non-stenosed control veins from uremic, pre-dialysis patients, and in 15 non-stenosed control saphenous veins obtained from patients undergoing aortocoronary bypass grafting. Immunohistochemistry was performed on snap-frozen tissue specimens using antibodies recognizing either the latency-associated peptide of TGF-beta1 (96-1), LTBP-1 (Ab39) or IGF-I. Serum levels of TGF-beta1 and IGF-I were determined by commercially available IRMA. RESULTS: In stenosed hemodialysis fistulas, a pronounced intimal thickening with deposition of ECM was observed with light and electron microscopy. Infiltrating cells were seen in stenosed vessels, mostly in areas of intimal hyperplasia and in the media. TGF-beta1, LTBP-1 and IGF-I expression were mostly localized in the neointimal and medial layers, and were significantly higher than in the control groups. A positive correlation between the presence of inflammatory cells and the staining intensity for TGF-beta1, LTBP-1 and IGF-I was found in all vessels analyzed. CONCLUSION: Neointimal thickening of primary arteriovenous fistulas represents a local inflammatory process and appears to be associated with increased protein expression of TGF-beta1 and IGF-I. While local IGF-I is likely to stimulate smooth muscle cell proliferation in this setting, TGF-beta1 may be an important trigger of ECM production and deposition.

Arteriovenous Shunt, Surgical↗
PubMed2002

Virtual reality and 3D visualizations in heart surgery education.

BACKGROUND: Computer assisted teaching plays an increasing role in surgical education. The presented paper describes the development of virtual reality (VR) and 3D visualizations for educational purposes concerning aortocoronary bypass grafting and their prototypical implementation into a database-driven and internet-based educational system in heart surgery. MATERIALS AND METHODS: A multimedia storyboard has been written and digital video has been encoded. Understanding of these videos was not always satisfying; therefore, additional 3D and VR visualizations have been modelled as VRML, QuickTime, QuickTime Virtual Reality and MPEG-1 applications. An authoring process in terms of integration and orchestration of different multimedia components to educational units has been started. RESULTS: A virtual model of the heart has been designed. It is highly interactive and the user is able to rotate it, move it, zoom in for details or even fly through. It can be explored during the cardiac cycle and a transparency mode demonstrates coronary arteries, movement of the heart valves, and simultaneous blood-flow. Myocardial ischemia and the effect of an IMA-Graft on myocardial perfusion is simulated. Coronary artery stenoses and bypass-grafts can be interactively added. 3D models of anastomotique techniques and closed thrombendarterectomy have been developed. Different visualizations have been prototypically implemented into a teaching application about operative techniques. CONCLUSIONS: Interactive virtual reality and 3D teaching applications can be used and distributed via the World Wide Web and have the power to describe surgical anatomy and principles of surgical techniques, where temporal and spatial events play an important role, in a way superior to traditional teaching methods.

Computer Simulation↗