Validation of Use of Flipped Classroom for Surgery Core Clerkships.

BACKGROUND: The flipped classroom (FC) is an integrated learning paradigm that equips students with self-directed study materials before scheduled meeting times allowing for the deeper application of acquired knowledge with an instructor. There is limited data on the application of FC to clinical undergraduate medical education and particularly as it applies to a surgical clerkship. METHODS: This study is a four-year retrospective study that includes two cohorts of students who matriculated through two training paradigms, traditional classroom (TC) and FC. Information regarding the FC cohort was collected from June 2018 to July 2020 (N=166). A two-year matched historical cohort of students enrolled in the clerkship and taught with the TC paradigm from June 2016 to July 2018 was used for comparison (N=157). The primary aim of this study is to assess the National Board of Medical Examiners (NBME) surgery shelf performance when the FC model is utilized compared to the TC model. This study will validate a prior similar study that had a smaller cohort with different secondary endpoints. Therefore, the secondary aim of this study assesses how teaching style can affect other performance metrics of a rotation (such as clinical performance, quizzes, Objective Structured Clinical Examinations (OSCE), and practicums) and how time was utilized by faculty, staff, and students. RESULTS: There was no difference in overall NBME surgery shelf performance when comparing the FC to the traditional classroom teaching (68.94 vs 70.34, P= 0.1667). Likewise, there was no difference in quiz performance. The FC did allow instructors to spend more time in other clinical components of the curriculum leading to a significant difference in student practicum (84.2 vs 88.26, P = 0.0186) and OSCE grades (87.54 vs 90.58, P <0.0001). CONCLUSION: The surgery NBME shelf performance is not compromised by FC and therefore can be used as an alternative to traditional classroom setting for teaching medical knowledge to surgery clerkship students. In addition, the FC can improve time management for instructors allowing for improved teaching and development in other components of the surgery curriculum.

Phosphorylation of PP1 Regulator Sds22 by PLK1 Ensures Accurate Chromosome Segregation.

During cell division, accurate chromosome segregation is tightly regulated by Polo-like kinase 1 (PLK1) and opposing activities of Aurora B kinase and protein phosphatase 1 (PP1). However, the regulatory mechanisms underlying the aforementioned hierarchical signaling cascade during mitotic chromosome segregation have remained elusive. Sds22 is a conserved regulator of PP1 activity, but how it regulates PP1 activity in space and time during mitosis remains elusive. Here we show that Sds22 is a novel and cognate substrate of PLK1 in mitosis, and the phosphorylation of Sds22 by PLK1 elicited an inhibition of PP1-mediated dephosphorylation of Aurora B at threonine 232 (Thr232) in a dose-dependent manner. Overexpression of a phosphomimetic mutant of Sds22 causes a dramatic increase in mitotic delay, whereas overexpression of a non-phosphorylatable mutant of Sds22 results in mitotic arrest. Mechanistically, the phosphorylation of Sds22 by PLK1 strengthens the binding of Sds22 to PP1 and inhibits the dephosphorylation of Thr232 of Aurora B to ensure a robust, error-free metaphase-anaphase transition. These findings delineate a conserved signaling hierarchy that orchestrates dynamic protein phosphorylation and dephosphorylation of critical mitotic regulators during chromosome segregation to guard chromosome stability.