Effects of interactive instructional techniques in a web-based peripheral nervous system component for human anatomy.

BACKGROUND: This study investigated the effects of interactive instructional techniques in a web-based peripheral nervous system (PNS) component of a first year medical school human anatomy course. METHOD: Existing data from 9 years of instruction involving 856 students were used to determine (1) the effect of web-based interactive instructional techniques on written exam item performance and (2) differences between student opinions of the benefit level of five different types of interactive learning objects used. The interactive learning objects included Patient Case studies, review Games, Simulated Interactive Patients (SIP), Flashcards, and unit Quizzes. RESULTS: Exam item analysis scores were found to be significantly higher (p < 0.05) for students receiving the instructional treatment incorporating the web-based interactive learning objects than for students not receiving this treatment. Questionnaires using a five-point Likert scale were analysed to determine student opinion ratings of the interactive learning objects. Students reported favorably on the benefit level of all learning objects. Students rated the benefit level of the Simulated Interactive Patients (SIP) highest, and this rating was significantly higher (p < 0.05) than all other learning objects. CONCLUSION: This study suggests that web-based interactive instructional techniques improve student exam performance. Students indicated a strong acceptance of Simulated Interactive Patient learning objects.

Outcomes from building system courseware for teaching and testing in a discipline-based human structure curriculum.

This study investigated the educational benefits of system-based lecture notes and interactive learning objects in a peripheral nervous system component of a traditional first-year medical school human anatomy course. The impetus for the investigation was anecdotal evidence suggesting enhanced learner satisfaction with the learning resources. Retrospective review of existing data from 2006 to 2009 was undertaken to quantify (1) the effects of Web-based system courseware on examination item performance, and (2) differences among learner opinions regarding the benefit level of the five different types of interactive learning objects as evaluated by instructional design questionnaires. Interactive patient-based case studies (IPCS) and review games (Games), simulated interactive patients (SIP), flashcards, and unit quizzes (Quizzes) developed in-house have been peer-reviewed and published in MedEdPORTAL. Statistics included one-way analysis of variance, Tukey's post hoc test, and power meta-analysis (d). Examination item analysis scores remained significantly higher (P ≤ 0.05; d = 0.3938) for learners receiving the instructional treatment incorporating system-based lecture notes and interactive learning objects than for those not receiving this treatment. Using questionnaires with a five-point Likert scale, students reported favorably on the benefit level of all learning objects. They rated the SIP and IPCS significantly higher (P ≤0.05) and games significantly lower (P ≤ 0.05) than in previous years, indicating a change in learner preferences. This study reaffirms that online system-based instructional techniques improve student examination performance and overall student satisfaction. Learners indicated stronger preferences for SIP and IPCS over exercises encouraging passive memorization of anatomical content.

Insulin enhances proliferation and viability of human umbilical vein endothelial cells.

This investigation is a follow-up to our previous in vivo studies revealing that rapid stretch increases tissue insulin in murine skin flaps, coincident with the up-regulation of key angiogenic effectors and enhanced vascularization. In the present study, we used human umbilical vein endothelial cells (HUVECs) as an in vitro model system to determine the role of insulin in the chemical signals regulating the processes of proliferation and viability (survival). MTT-based colorimetric methods demonstrated that insulin enhances proliferation and survival of HUVECs. Western blot analysis revealed that protein kinase B (pAkt [Thr(308)]) and vascular endothelial growth factor (VEGF) were the insulin-responsive intermediates in proliferating endothelial cells (ECs). In insulin-enhanced survival, both pAkt (Thr(308)) and pAkt (Ser(473)) were activated in HUVECs. However, no change in VEGF expression accompanied pAkt activation. The beneficial effects of insulin were abrogated by insulin receptor (IR)/insulin-like growth factor receptor (IGFR) or phosphoinositide-3 kinase (PI3-K) blockade, suggesting that insulin-induced EC proliferation and viability are mediated through pIR/pIGFR and PI3-K effectors. These data provide new insights into the beneficial effects of insulin on vascularization and tissue viability, providing a mechanistic link to the enhancement of healing in acutely stretched skin.

Acute stretch promotes endothelial cell proliferation in wounded healing mouse skin.

We have developed a novel in vivo model utilizing acute stretch to investigate endothelial cell proliferation as a marker of vascular growth in healing mouse skin. This study is a follow-up to ones revealing immediate stretch improves blood flow, decreases total tissue necrosis, and induces tissue insulin transcription. Dorsal distally based flaps of skin were stretched for 3 min using linear (skin hook) plus hemispherical load cycling (inflated subcutaneous silicone catheter). Unstretched, wounded skin along the back and sternum served as postoperative controls. Laser Doppler flowmetry demonstrated a threefold increase in flap perfusion at postoperative day 7. A stretch-induced sixfold increase in endothelial cell mitogenesis accompanied enhancements in blood flow and extracorporal wound healing over the sternum. Western blots revealed up-regulation/activation of insulin and mitogenic signaling intermediates in stretched skin. Activated insulin and insulin growth factor receptors (pIR/pIGFR), protein kinase B (Akt, pAkt), vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor 2 (flk-1) were among the identified stretch-responsive intermediates. These results indicate the benefits of acute stretch are mediated through enhanced vascularity as evidenced by endothelial cell mitogenesis and up-regulation/activation of insulin and key angiogenic effectors in dorsal distally based skin flaps.

A mouse model for studying rapid intraoperative methods of skin closure and wound healing.

BACKGROUND: We re-examine the adequacy of an albino (hairless) mouse dorsal distally based skin flap model by determining elastic modulus and by assessing viability after application of rapid intermittent stretch to facilitate wound closure. MATERIAL/METHODS: Modulus of elasticity was determined with materials testing. Viability was accessed by laser Doppler flowmetry and by quantifying marginal tissue necrosis (mm2) at 5 days. Effective length gained and tension relieved were measured by subjecting flaps to simple undermining plus 3-10 g of initial tension (linear stretch) using a skin hook. Immediate hemispherical stretch was applied with an implanted subcutaneous silicone balloon (Rapid Intraoperative Tissue Expansion or RITE) at 1 or 2 cycles of 3-8 min and 6-12 ml for each cycle. Flaps subjected to simple and extensive undermining with or without application of initial linear stretch served as postoperative controls. RESULTS: The elastic modulus of 9.85 (1.02) N/mm2 approximated the skin of the human face. Flowmetry demonstrated that all flaps were adequately perfused. Stretching significantly decreased flap tension and increased flap length over simple undermining alone. It drastically improved flap viability by provoking a 50-75% decline in 5-day necrosis. The benefits were dependent upon the initial linear tension applied, but independent of the timing, cycling, and volume selected for RITE and the flap dimensions at closure. CONCLUSIONS: Results demonstrate that the albino (hairless) mouse dorsal distally based skin flap is a reliable model for studying wound closure and that rapid intermittent stretching in this model facilitates closure and wound healing.