Team-Based Learning in a Pipeline Course in Medical Microbiology for Under-Represented Student Populations in Medicine Improves Learning of Microbiology Concepts.

As part of an undergraduate pipeline program at our institution for students from underrepresented minorities in medicine backgrounds, we created an intensive four-week medical microbiology course. Team-based learning (TBL) was implemented in this course to enhance student learning of course content. Three different student cohorts participated in the study, and there were no significant differences in their prior academic achievement based on their undergraduate grade point average (GPA) and pre-course examination scores. Teaching techniques included engaged lectures using an audience response system, TBL, and guided self-directed learning. We hypothesized that more active learning exercises, irrespective of the amount of lecture time, would help students master course content. In year 2 as compared with year 1, TBL exercises were decreased from six to three with a concomitant increase in lecture time, while in year 3, TBL exercises were increased from three to six while maintaining the same amount of lecture time as in year 2. As we hypothesized, there was significant (p < 0.01) improvement in performance on the post-course examination in years 1 and 3 compared with year 2, when only three TBL exercises were used. In contrast to the students' perceptions that more lecture time enhances learning of course content, our findings suggest that active learning strategies, such as TBL, are more effective than engaged lectures in improving student understanding of course content, as measured by post-course examination performance. Introduction of TBL in pipeline program courses may help achieve better student learning outcomes.

Pigment epithelium-derived factor expression in the developing mouse eye.

PURPOSE: Pigment Epithelium-Derived Factor (PEDF) is a 50 kDa secretable protein with neuroprotective, neurotrophic, and antiangiogenic properties. Expression patterns in the human eye suggest that modulation of this protein over time and place may play a role in development of normal ocular vasculature. Because of the potential importance of normal PEDF expression patterns in controlling ocular blood vessel growth in health and disease, we characterized these patterns over the period of retinal vascular development in the mouse. METHODS: Eyes from CD1 mice (embryonic days E 14.5, 18.5, P0, P4, P7, P14, and Adult) were cryosectioned and examined. A polyclonal PEDF antibody was used to locate PEDF protein using immunohistochemical techniques while a PEDF RNA probe was used to localize PEDF mRNA by in situ hybridization. RESULTS: Immunohistochemical and in situ hybridization showed initial expression in the ciliary body and choroid during mid-gestation. Near term, relative protein levels increased in the ganglion cell layer and remained high through the first two weeks postnatal. Levels qualitatively decreased after this point but persisted through adulthood. Relative levels of expression in the inner retina were much higher at all timepoints than in the outer retina. CONCLUSIONS: These expression patterns likely maintain the vitreous and aqueous humors as avascular spaces and may also control vascular development in the inner/outer retina.

Localization of pigment epithelium derived factor (PEDF) in developing and adult human ocular tissues.

PURPOSE: To localize pigment epithelium-derived factor (PEDF) in developing and adult human ocular tissues. METHODS: PEDF was localized in fetal and adult eyes by immunofluorescence with a polyclonal antibody (pAb) against amino acids 327-343 of PEDF, or a monoclonal antibody (mAb) against the C-terminal 155 amino acids of PEDF. Specificity of the antibodies was documented by Western blotting. PEDF mRNA was localized in adult retina by in situ hybridization. RESULTS: In developing retinas (7.4 to 21.5 fetal weeks, Fwks), pAb anti-PEDF labeled retinal pigment epithelium (RPE) granules, developing cones, some neuroblasts and many cells in the ganglion cell layer (GCL). In adult retinas, pAb anti-PEDF labeled rod and cone cytoplasm and nuclei of rods but not cones. Cells in the INL and GCL, choroid, corneal epithelium and endothelium, and ciliary body were also pAb PEDF-positive. Preadsorption of pAb anti-PEDF with the immunizing peptide blocked specific labeling in retina and other tissues, except for photoreceptor outer segments. In agreement with the immunolocalization with pAb anti-PEDF, in situ hybridization revealed PEDF mRNA in the RPE, photoreceptors, inner nuclear layer cells and ganglion cells in adult retina. In developing retinas 18 Fwks and older, and in adult retinas, mAb anti-PEDF labeled the interphotoreceptor matrix (IPM). Western blots of retina, cornea, and ciliary body/iris with pAb anti-PEDF produced several bands at about 46 kDa. With mAb anti-PEDF, retina produced one band at about 46 kDa; cornea and ciliary body/iris had several bands at about 46 kDa. CONCLUSIONS: PEDF, originally reported as a product of RPE cells, is present in photoreceptors and inner retinal cell types in developing and adult human eyes. Photoreceptors and RPE may secrete PEDF into the IPM.