Which Internal Medicine Clerkship Characteristics Are Associated With Students’ Performance on the NBME Medicine Subject Exam? A Multi-Institutional Analysis

Purpose To identify which internal medicine clerkship characteristics may relate to NBME Medicine Subject Examination scores, given the growing trend toward earlier clerkship start dates. Method The authors used linear mixed effects models (univariable and multivariable) to determine associations between medicine exam performance and clerkship characteristics (longitudinal status, clerkship length, academic start month, ambulatory clinical experience, presence of a study day, involvement in a combined clerkship, preclinical curriculum type, medicine exam timing). Additional covariates included number of NBME clinical subject exams used, number of didactic hours, use of a criterion score for passing the medicine exam, whether medicine exam performance was used to designate clerkship honors, and United States Medical Licensing Examination Step 1 performance. The sample included 24,542 examinees from 62 medical schools spanning 3 academic years (2011–2014). Results The multivariable analysis found no significant association between clerkship length and medicine exam performance (all pairwise P > .05). However, a small number of examinees beginning their academic term in January scored marginally lower than those starting in July (P < .001). Conversely, examinees scored higher on the medicine exam later in the academic year (all pairwise P < .001). Examinees from schools that used a criterion score for passing the medicine exam also scored higher than those at schools that did not (P < .05). Step 1 performance remained positively associated with medicine exam performance even after controlling for all other variables in the model (P < .001). Conclusions In this sample, the authors found no association between many clerkship variables and medicine exam performance. Instead, Step 1 performance was the most powerful predictor of medicine exam performance. These findings suggest that medicine exam performance reflects the overall medical knowledge students accrue during their education rather than any specific internal medicine clerkship characteristics

Loss of myosin Vb promotes apical bulk endocytosis in neonatal enterocytes

In patients with inactivating mutations in myosin Vb (Myo5B), enterocytes show large inclusions lined by microvilli. The origin of inclusions in small-intestinal enterocytes in microvillus inclusion disease is currently unclear. We postulated that inclusions in Myo5b KO mouse enterocytes form through invagination of the apical brush border membrane. 70-kD FITC-dextran added apically to Myo5b KO intestinal explants accumulated in intracellular inclusions. Live imaging of Myo5b KO–derived enteroids confirmed the formation of inclusions from the apical membrane. Treatment of intestinal explants and enteroids with Dyngo resulted in accumulation of inclusions at the apical membrane. Inclusions in Myo5b KO enterocytes contained VAMP4 and Pacsin 2 (Syndapin 2). Myo5b;Pacsin 2 double-KO mice showed a significant decrease in inclusion formation. Our results suggest that apical bulk endocytosis in Myo5b KO enterocytes resembles activity-dependent bulk endocytosis, the primary mechanism for synaptic vesicle uptake during intense neuronal stimulation. Thus, apical bulk endocytosis mediates the formation of inclusions in neonatal Myo5b KO enterocytes.United States Department of Health & Human Services - National Institutes of Health (NIH) - USA [R01 DK48370, R01 DK70856, F32 DK111101, R01 DK111949, R01 DK095811, 1R01 DK109701]; Vanderbilt Digestive Disease Center [P30 DK058404]; Vanderbilt-Ingram Cancer Center [P30 CA68485]; Shared Equipment Grant - US Department of Veteran Affairs [1IS1BX003097]6 month embargo; published online: 27 September 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Challenges and opportunities for integrating lake ecosystem modelling approaches

A large number and wide variety of lake ecosystem models have been developed and published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more models largely following the concept of others (‘reinventing the wheel’). The other challenge is to avoid focusing on only one type of model, while ignoring new and diverse approaches that have become available (‘having tunnel vision’). In this paper, we aim at improving the awareness of existing models and knowledge of concurrent approaches in lake ecosystem modelling, without covering all possible model tools and avenues. First, we present a broad variety of modelling approaches. To illustrate these approaches, we give brief descriptions of rather arbitrarily selected sets of specific models. We deal with static models (steady state and regression models), complex dynamic models (CAEDYM, CE-QUAL-W2, Delft 3D-ECO, LakeMab, LakeWeb, MyLake, PCLake, PROTECH, SALMO), structurally dynamic models and minimal dynamic models. We also discuss a group of approaches that could all be classified as individual based: super-individual models (Piscator, Charisma), physiologically structured models, stage-structured models and trait-based models. We briefly mention genetic algorithms, neural networks, Kalman filters and fuzzy logic. Thereafter, we zoom in, as an in-depth example, on the multi-decadal development and application of the lake ecosystem model PCLake and related models (PCLake Metamodel, Lake Shira Model, IPH-TRIM3D-PCLake). In the discussion, we argue that while the historical development of each approach and model is understandable given its ‘leading principle’, there are many opportunities for combining approaches. We take the point of view that a single ‘right’ approach does not exist and should not be strived for. Instead, multiple modelling approaches, applied concurrently to a given problem, can help develop an integrative view on the functioning of lake ecosystems. We end with a set of specific recommendations that may be of help in the further development of lake ecosystem model