Samantha Halman

Glycine transporter type 1 blockade changes NMDA receptor-mediated responses and LTP in hippocampal CA1 pyramidal cells by altering extracellular glycine levels

Long‐term potentiation (LTP) in the hippocampal CA1 region requires the activation of NMDA receptors (NMDARs). NMDAR activation in turn requires membrane depolarization as well as the binding of glutamate and its coagonist glycine. Previous pharmacological studies suggest that the glycine transporter type 1 (GlyT1) maintains subsaturating concentrations of glycine at synaptic NMDARs. Antagonists of GlyT1 increase levels of glycine in the synaptic cleft and, like direct glycine site agonists, can augment NMDAR currents and NMDAR‐mediated functions such as LTP. In addition, stimulation of the glycine site initiates signalling through the NMDAR complex, priming the receptors for clathrin‐dependent endocytosis. We have used a new potent GlyT1 antagonist, CP‐802,079, with whole‐cell patch‐clamp recordings in acute rat hippocampal slices to determine the effect of GlyT1 blockade on LTP. Reverse microdialysis experiments in the hippocampus of awake, freely moving rats, showed that this drug elevated only the extracellular concentration of glycine. We found that CP‐802,079, sarcosine and glycine significantly increased the amplitude of the NMDAR currents and LTP. In contrast, application of higher concentrations of CP‐802,079 and glycine slightly reduced NMDAR currents and did not increase LTP. Overall, these data suggest that the level of glycine present in the synaptic cleft tightly regulates the NMDAR activity. This level is kept below the ‘set point’ of the NMDAR internalization priming mechanism by the presence of GlyT1‐dependent uptake.

The sigma‐1 receptor modulates NMDA receptor synaptic transmission and plasticity via SK channels in rat hippocampus

The sigma receptor (σR), once considered a subtype of the opioid receptor, is now described as a distinct pharmacological entity. Modulation of N‐methyl‐d‐aspartate receptor (NMDAR) functions by σR‐1 ligands is well documented; however, its mechanism is not fully understood. Using patch‐clamp whole‐cell recordings in CA1 pyramidal cells of rat hippocampus and (+)pentazocine, a high‐affinity σR‐1 agonist, we found that σR‐1 activation potentiates NMDAR responses and long‐term potentiation (LTP) by preventing a small conductance Ca2+‐activated K+ current (SK channels), known to shunt NMDAR responses, to open. Therefore, the block of SK channels and the resulting increased Ca2+ influx through the NMDAR enhances NMDAR responses and LTP. These results emphasize the importance of the σR‐1 as postsynaptic regulator of synaptic transmission.

Reduced glycine transporter type 1 expression leads to major changes in glutamatergic neurotransmission of CA1 hippocampal neurones in mice.

To investigate the effects of persistent elevation of synaptic glycine at Schaffer collateral–CA1 synapses of the hippocampus, we studied the glutamatergic synaptic transmission in acute brain slices from mice with reduced expression of glycine transporter type 1 (GlyT1+/−) as compared to wild type (WT) littermates using whole‐cell patch‐clamp recordings of CA1 pyramidal cells. We observed faster decay kinetics, reduced ifenprodil sensitivity and increased zinc‐induced antagonism in N‐methyl‐d‐aspartate receptor (NMDAR) currents of GlyT1+/− mice. Moreover, the ratio α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionic acid receptor (AMPAR)/NMDAR was decreased in mutants compared to WT. Surprisingly, this change was associated with a reduction in the number of AMPARs expressed at the CA1 synapses in the mutants compared to WT. Overall, these findings highlight the importance of GlyT1 in regulating glutamatergic neurotransmission.

Internal Medicine Point-of-Care Ultrasound Curriculum: Consensus Recommendations from the Canadian Internal Medicine Ultrasound (CIMUS) Group

Bedside point-of-care ultrasound (POCUS) is increasingly used to assess medical patients. At present, no consensus exists for what POCUS curriculum is appropriate for internal medicine residency training programs. This document details the consensus-based recommendations by the Canadian Internal Medicine Ultrasound (CIMUS) group, comprising 39 members, representing 14 institutions across Canada. Guiding principles for selecting curricular content were determined a priori. Consensus was defined as agreement by at least 80% of the members on POCUS applications deemed appropriate for teaching and assessment of trainees in the core (internal medicine postgraduate years [PGY] 1–3) and expanded (general internal medicine PGY 4–5) training programs. We recommend four POCUS applications for the core PGY 1–3 curriculum (inferior vena cava, lung B lines, pleural effusion, and abdominal free fluid) and three ultrasound-guided procedures (central venous catheterization, thoracentesis, and paracentesis). For the expanded PGY 4–5 curriculum, we recommend an additional seven applications (internal jugular vein, lung consolidation, pneumothorax, knee effusion, gross left ventricular systolic function, pericardial effusion, and right ventricular strain) and four ultrasound-guided procedures (knee arthrocentesis, arterial line insertion, arterial blood gas sampling, and peripheral venous catheterization). These recommendations will provide a framework for training programs at a national level.

Ankle-Brachial Index on Kilimanjaro: Lessons from High Altitude

Abstract Objective.—This study investigated the effects of a high–sympathetic stimulus environment (high-altitude hypoxia) on limb-specific systolic blood pressure (sBP) and ankle-brachial index (ABI) in normal volunteers. We hypothesized that currently accepted normal values for ABI may in fact not reflect an actual normal vascular state in all patients. Methods.—Twenty climbers (17 males, 3 females) from Gatineau-Hull (Québec, Canada) participated in this study and ascended Mount Kilimanjaro, Africa. Ankle-brachial index measurements were performed at sea level and on Mount Kilimanjaro at ∼4100 m. The data were analyzed using predictive analytics software SPSS 14.0. Data obtained at sea level were compared to those obtained at ∼4100 m, with participants serving as their own controls. Results.—Ankle-brachial indices measured at ∼4100 m (mean = 1.20) were greater than those measured at sea level (mean = 0.97) (n = −6.23; 95% CI: −.32 to −.17; P < .001). There were no significant differences between the systolic brachial pressures at ∼4100 m when compared to those at sea level (P = .814). Contrarily, systolic ankle pressures at sea level (mean = 132) were significantly greater than those measured at ∼4100 m (mean = 152) (t = −3.5, 95% CI: −29 to −7.4; P = .002). Conclusions.—This study is the first to physiologically demonstrate that in response to a high adrenergic stimulus in healthy volunteers there is a greater increase in sBP in the legs vs the arms.

Direct Observation of Clinical Skills Feedback Scale: Development and Validity Evidence

ABSTRACT Construct: This article describes the development and validity evidence behind a new rating scale to assess feedback quality in the clinical workplace. Background: Competency-based medical education has mandated a shift to learner-centeredness, authentic observation, and frequent formative assessments with a focus on the delivery of effective feedback. Because feedback has been shown to be of variable quality and effectiveness, an assessment of feedback quality in the workplace is important to ensure we are providing trainees with optimal learning opportunities. The purposes of this project were to develop a rating scale for the quality of verbal feedback in the workplace (the Direct Observation of Clinical Skills Feedback Scale [DOCS-FBS]) and to gather validity evidence for its use. Approach: Two panels of experts (local and national) took part in a nominal group technique to identify features of high-quality feedback. Through multiple iterations and review, 9 features were developed into the DOCS-FBS. Four rater types (residents n = 21, medical students n = 8, faculty n = 12, and educators n = 12) used the DOCS-FBS to rate videotaped feedback encounters of variable quality. The psychometric properties of the scale were determined using a generalizability analysis. Participants also completed a survey to gather data on a 5-point Likert scale to inform the ease of use, clarity, knowledge acquisition, and acceptability of the scale. Results: Mean video ratings ranged from 1.38 to 2.96 out of 3 and followed the intended pattern suggesting that the tool allowed raters to distinguish between examples of higher and lower quality feedback. There were no significant differences between rater type (range = 2.36–2.49), suggesting that all groups of raters used the tool in the same way. The generalizability coefficients for the scale ranged from 0.97 to 0.99. Item-total correlations were all above 0.80, suggesting some redundancy in items. Participants found the scale easy to use (M = 4.31/5) and clear (M = 4.23/5), and most would recommend its use (M = 4.15/5). Use of DOCS-FBS was acceptable to both trainees (M = 4.34/5) and supervisors (M = 4.22/5). Conclusions: The DOCS-FBS can reliably differentiate between feedback encounters of higher and lower quality. The scale has been shown to have excellent internal consistency. We foresee the DOCS-FBS being used as a means to provide objective evidence that faculty development efforts aimed at improving feedback skills can yield results through formal assessment of feedback quality.

Feedback in the OSCE: What Do Residents Remember?

Abstract Theory: The move to competency-based education has heightened the importance of direct observation of clinical skills and effective feedback. The Objective Structured Clinical Examination (OSCE) is widely used for assessment and affords an opportunity for both direct observation and feedback to occur simultaneously. For feedback to be effective, it should include direct observation, assessment of performance, provision of feedback, reflection, decision making, and use of feedback for learning and change. Hypotheses: If one of the goals of feedback is to engage students to think about their performance (i.e., reflection), it would seem imperative that they can recall this feedback both immediately and into the future. This study explores recall of feedback in the context of an OSCE. Specifically, the purpose of this study was to (a) determine the amount and the accuracy of feedback that trainees remember immediately after an OSCE, as well as 1 month later, and (b) assess whether prompting immediate recall improved delayed recall. Methods: Internal medicine residents received 2 minutes of verbal feedback from physician examiners in the context of an OSCE. The feedback was audio-recorded and later transcribed. Residents were randomly allocated to the immediate recall group (immediate-RG; n = 10) or the delayed recall group (delayed-RG; n = 8). The immediate-RG completed a questionnaire prompting recall of feedback received immediately after the OSCE, and then again 1 month later. The delayed-RG completed a questionnaire only 1 month after the OSCE. The total number and accuracy of feedback points provided by examiners were compared to the points recalled by residents. Results comparing recall at 1 month between the immediate-RG and the delayed-RG were also studied. Results: Physician examiners provided considerably more feedback points (M = 16.3) than the residents recalled immediately after the OSCE (M = 2.61, p < .001). There was no significant difference between the number of feedback points recalled upon completion of the OSCE (2.61) compared to 1 month later (M = 1.96, p = .06, Cohens d = .70). Prompting immediate recall did not improve later recall. The mean accuracy score for feedback recall immediately after the OSCE was 4.3/9 or “somewhat representative,” and at 1 month the score dropped to 3.5/9 or “not representative” (ns). Conclusion: Residents recall very few feedback points immediately after the OSCE and 1 month later. The feedback points that are recalled are neither very accurate nor representative of the feedback actually provided.

Done or Almost Done? Improving OSCE Checklists to Better Capture Performance in Progress Tests

ABSTRACT Construct: The impact of using nonbinary checklists for scoring residents from different levels of training participating in objective structured clinical examination (OSCE) progress tests was explored. Background: OSCE progress tests typically employ similar rating instruments as traditional OSCEs. However, progress tests differ from other assessment modalities because learners from different stages of training participate in the same examination, which can pose challenges when deciding how to assign scores. In an attempt to better capture performance, nonbinary checklists were introduced in two OSCE progress tests. The purposes of this study were (a) to identify differences in the use of checklist options (e.g., done satisfactorily, attempted, or not done) by task type, (b) to analyze the impact of different scoring methods using nonbinary checklists for two OSCE progress tests (nonprocedural and procedural) for Internal Medicine residents, and (c) to determine which scoring method is better suited for a given task. Approach: A retrospective analysis examined differences in scores (n = 119) for two OSCE progress tests (procedural and nonprocedural). Scoring methods (hawk, dove, and hybrid) varied in stringency in how they awarded marks for nonbinary checklist items that were rated as done satisfactorily, attempted, or not done. Difficulty, reliability (internal consistency), item-total correlations and pass rates were compared for each OSCE using the three scoring methods. Results: Mean OSCE scores were highest using the dove method and lowest using the hawk method. The hawk method resulted in higher item-total correlations for most stations, but there were differences by task type. Overall score reliability calculated using the three methods did not differ significantly. Pass–fail status differed as a function of scoring methods and exam type, with the hawk and hybrid methods resulting in higher failure rates for the nonprocedural OSCE and the dove method resulting in a higher failure rate for the procedural OSCE. Conclusion: The use of different scoring methods for nonbinary OSCE checklists resulted in differences in mean scores and pass–fail status. The results varied with procedural and nonprocedural OSCEs.

Context, time, and building relationships: bringing in situ feedback into the conversation

In his landmark 1983 paper, Ende posited that feedback is essential to learning in clinical education. He outlined the benefits of feedback and provided guidelines for sharing feedback. Ende proposed some prescient scenarios for ideal situations for the sharing of feedback that foreshadowed the current direction seen in the literature on ‘coaching’ relationships between clinical teachers and trainees.

The implementation and evaluation of an e-Learning training module for observed structured clinical examination (OSCE) raters in Canada

Improving the reliability and consistency of objective structured clinical examination (OSCE) raters’ marking poses a continual challenge in medical education. The purpose of this study was to evaluate an e-Learning training module for OSCE raters who participated in the assessment of third-year medical students at the University of Ottawa, Canada. The effects of online training and those of traditional in-person (face-to-face) orientation were compared. Of the 90 physicians recruited as raters for this OSCE, 60 consented to participate (67.7%) in the study in March 2017. Of the 60 participants, 55 rated students during the OSCE, while the remaining 5 were back-up raters. The number of raters in the online training group was 41, while that in the traditional in-person training group was 19. Of those with prior OSCE experience (n= 18) who participated in the online group, 13 (68%) reported that they preferred this format to the in-person orientation. The total average time needed to complete the online module was 15 minutes. Furthermore, 89% of the participants felt the module provided clarity in the rater training process. There was no significant difference in the number of missing ratings based on the type of orientation that raters received. Our study indicates that online OSCE rater training is comparable to traditional face-to-face orientation.