Molecular characterization of retinal stem cells and their niches in adult zebrafish

BACKGROUND: The persistence in adult teleost fish of retinal stem cells that exhibit all of the features of true 'adult stem cells' – self-renewal, multipotency, and the capacity to respond to injury by mitotic activation with the ability to regenerate differentiated tissues – has been known for several decades. However, the specialized cellular and molecular characteristics of these adult retinal stem cells and the microenvironmental niches that support their maintenance in the differentiated retina and regulate their activity during growth and regeneration have not yet been elucidated. RESULTS: Our data show that the zebrafish retina has two kinds of specialized niches that sustain retinal stem cells: 1) a neuroepithelial germinal zone at the interface between neural retina and ciliary epithelium, called the ciliary marginal zone (CMZ), a continuous annulus around the retinal circumference, and 2) the microenvironment around some Müller glia in the differentiated retina. In the uninjured retina, scattered Müller glia (more frequently those in peripheral retina) are associated with clusters of proliferating retinal progenitors that are restricted to the rod photoreceptor lineage, but following injury, the Müller-associated retinal progenitors can function as multipotent retinal stem cells to regenerate other types of retinal neurons. The CMZ has several features in common with the neurogenic niches in the adult mammalian brain, including access to the apical epithelial surface and a close association with blood vessels. Müller glia in the teleost retina have a complex response to local injury that includes some features of reactive gliosis (up-regulation of glial fibrillary acidic protein, GFAP, and re-entry into the cell cycle) together with dedifferentiation and re-acquisition of phenotypic and molecular characteristics of multipotent retinal progenitors in the CMZ (diffuse distribution of N-cadherin, activation of Notch-Delta signaling, and expression of rx1, vsx2/Chx10, and pax6a) along with characteristics associated with radial glia (expression of brain lipid binding protein, BLBP). We also describe a novel specific marker for Müller glia, apoE. CONCLUSION: The stem cell niches that support multi-lineage retinal progenitors in the intact, growing and regenerating teleost retina have properties characteristic of neuroepithelia and neurogenic radial glia. The regenerative capacity of the adult zebrafish retina with its ability to replace lost retinal neurons provides an opportunity to discover the molecular regulators that lead to functional repair of damaged neural tissue

Factors influencing implementation of team-based learning in health sciences education

Abstract Background Limited studies have looked at factors that lead to successful implementation of team-based learning (TBL). The purpose of this study was to identify contextual factors associated with implementation of TBL with a larger pool of individuals

Fear of success, sex competition, and perceived task difficulty: variables affecting female performance

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Bibliography: leaves 32-35.Not availabl

Combining Expertise: Reflecting on a Team Approach to Curriculum Development and Implementation

Introduction This article discussed curriculum development and implementation using a unique collaboration of basic scientists and clinicians functioning as course co-directors. It explores the pros, cons, and unintended consequences of this integrated approach through reflections of the faculty involved. Methods Ten faculty participated in semi-structured phone interviews to reflect on their experiences. Results Analysis of interview transcripts revealed four key themes: (1) the value of the basic scientist and clinician partnership, (2) strategies for coordination, (3) balancing responsibilities, and (4) hierarchy and power. Discussion This study identified that both basic scientists and clinicians experienced benefits from using a course co-director collaborative approach to curriculum development and implementation. While challenges are also noted, the benefits of the collaboration were evident in course organization, course evaluation reports, student feedback, and USMLE Step I pass rate

Perspective: Guidelines for Reporting Team-Based Learning Activities in the Medical and Health Sciences Education Literature

Medical and health sciences educators are increasingly employing team-based learning (TBL) in their teaching activities. TBL is a comprehensive strategy for developing and using self-managed learning teams that has created a fertile area for medical education scholarship. However, because this method can be implemented in a variety of ways, published reports about TBL may be difficult to understand, critique, replicate, or compare unless authors fully describe their interventions. The authors of this article offer a conceptual model and propose a set of guidelines for standardizing the way that the results of TBL implementations are reported and critiqued. They identify and articulate the seven core design elements that underlie the TBL method and relate them to educational principles that maximize student engagement and learning within teams. The guidelines underscore important principles relevant to many forms of small-group learning. The authors suggest that following these guidelines when writing articles about TBL implementations should help standardize descriptive information in the medical and health sciences education literature about the essential aspects of TBL activities and allow authors and reviewers to successfully replicate TBL implementations and draw meaningful conclusions about observed outcomes

Perspective: Guidelines for Reporting Team-Based Learning Activities in the Medical and Health Sciences Education Literature

Medical and health sciences educators are increasingly employing team-based learning (TBL) in their teaching activities. TBL is a comprehensive strategy for developing and using self-managed learning teams that has created a fertile area for medical education scholarship. However, because this method can be implemented in a variety of ways, published reports about TBL may be difficult to understand, critique, replicate, or compare unless authors fully describe their interventions. The authors of this article offer a conceptual model and propose a set of guidelines for standardizing the way that the results of TBL implementations are reported and critiqued. They identify and articulate the seven core design elements that underlie the TBL method and relate them to educational principles that maximize student engagement and learning within teams. The guidelines underscore important principles relevant to many forms of small-group learning. The authors suggest that following these guidelines when writing articles about TBL implementations should help standardize descriptive information in the medical and health sciences education literature about the essential aspects of TBL activities and allow authors and reviewers to successfully replicate TBL implementations and draw meaningful conclusions about observed outcomes

Twelve tips for developing, implementing, and sustaining medical education fellowship programs: Building on new trends and solid foundations

Medical education fellowship programs (MEFPs) are a form of faculty development contributing to an organization\u27s educational mission and participants\u27 career development. Building an MEFP requires a systematic design, implementation, and evaluation approach which aligns institutional and individual faculty goals. Implementing an MEFP requires a team of committed individuals who provide expertise, guidance, and mentoring. Qualified MEFP directors should utilize instructional methods that promote individual and institutional short and long term growth. Directors must balance the use of traditional design, implementation, and evaluation methodologies with advancing trends that may support or threaten the acceptability and sustainability of the program. Drawing on the expertise of 28 MEFP directors, we provide twelve tips as a guide to those implementing, sustaining, and/or growing a successful MEFP whose value is demonstrated by its impacts on participants, learners, patients, teaching faculty, institutions, the greater medical education community, and the population\u27s health