The targeting and refinement of retinal projections to their primary targets in the brain has served as a model system to study the formation of sensory maps. Prior to the development of vision, immature retinas spontaneously generate correlated activity, called retinal waves, that has been demonstrated to play a critical role in map formation. However, these previous studies were based on anatomical techniques that labeled large clusters of retinal ganglion cell (RGC) axons. To gain further insights into the mechanisms that govern map formation, it is critical to visualize the normal development of individual retinal ganglion cell axons. Here, single-cell in vivo electroporation was used to transfect individual RGCs with DNA encoding the fluorescent protein GFP. In initial studies, I used this technique to determine the projection of individual RGCs in the dorsal lateral geniculate nucleus (dLGN) of the thalamus. In wildtype mice, single RGC axons branch several arbors at multiple points into the dLGN and these individual axonal branches increase in length and complexity over the first two postnatal weeks. In transgenic mice that lack normal retinal waves, single RGC termination zones were qualitatively larger and more diffuse than in wild-type mice. These findings suggest that correlated retinal activity is required for normal refinement of single retinogeniculate projections into compact termination zones that underlie organization of visual maps

Rationale and objectives

Studies show that problems with interprofessional collaboration can result in adverse patient outcomes. These problems are common in the field of radiology, where technology has decreased opportunities for direct communication and collaboration with referring physicians. To our knowledge, critical reflection has not been studied as an intervention to better understand one's own and/or others' roles in the context of an interprofessional team, or more specifically, to improve interprofessional collaboration between radiologists and other physicians.

Materials and methods

We trialed a reflective journaling assignment in our fourth year medical student general radiology elective. Student journal content was scored by percentage of comments reflecting on elective experiences versus recounting events. Content was categorized as "reflection" using an established measurement tool. Reflective content was evaluated to identify common themes.

Results

A total of 31 journals (178 entries and 26,749 words) were analyzed. Reflective content accounted for 43% of overall content and was subdivided into three categories: insight into one's own role and responsibilities as an ordering physician (20%), insight into a radiologist's role and responsibilities (12%), and thoughts on improving interprofessional collaboration with radiologists (11%).

Conclusions

Reflective writing allows students to explore their own role and responsibilities in the context of an interprofessional team and may improve interprofessional teamwork with radiologists.

Tissue morphogenesis and organ formation are the consequences of biochemical and biophysical cues that lead to cellular spatial patterning in development. To model such events in vitro, we use PEG-patterned substrates to geometrically confine human pluripotent stem cell colonies and spatially present mechanical stress. Modulation of the WNT/β-catenin pathway promotes spatial patterning via geometric confinement of the cell condensation process during epithelial-mesenchymal transition, forcing cells at the perimeter to express an OCT4+ annulus, which is coincident with a region of higher cell density and E-cadherin expression. The biochemical and biophysical cues synergistically induce self-organizing lineage specification and creation of a beating human cardiac microchamber confined by the pattern geometry. These highly defined human cardiac microchambers can be used to study aspects of embryonic spatial patterning, early cardiac development and drug-induced developmental toxicity.

Long-QT syndrome mutations can cause syncope and sudden death by prolonging the cardiac action potential (AP). Ion channels affected by mutations are various, and the influences of cellular calcium cycling on LQTS cardiac events are unknown. To better understand LQTS arrhythmias, we performed current-clamp and intracellular calcium ([Ca(2+)]i) measurements on cardiomyocytes differentiated from patient-derived induced pluripotent stem cells (iPS-CM). In myocytes carrying an LQT2 mutation (HERG-A422T), APs and [Ca(2+)]i transients were prolonged in parallel. APs were abbreviated by nifedipine exposure and further lengthened upon releasing intracellularly stored Ca(2+). Validating this model, control iPS-CM treated with HERG-blocking drugs recapitulated the LQT2 phenotype. In LQT3 iPS-CM, expressing NaV1.5-N406K, APs and [Ca(2+)]i transients were markedly prolonged. AP prolongation was sensitive to tetrodotoxin and to inhibiting Na(+)-Ca(2+) exchange. These results suggest that LQTS mutations act partly on cytosolic Ca(2+) cycling, potentially providing a basis for functionally targeted interventions regardless of the specific mutation site.