Oligodendrocyte precursor cells engulf synapses during circuit remodeling in mice.

Oligodendrocyte precursor cells (OPCs) give rise to myelinating oligodendrocytes throughout life, but the functions of OPCs are not limited to oligodendrogenesis. Here we show that OPCs contribute to thalamocortical presynapse elimination in the developing and adult mouse visual cortex. OPC-mediated synapse engulfment increases in response to sensory experience during neural circuit refinement. Our data suggest that OPCs may regulate synaptic connectivity in the brain independently of oligodendrogenesis.

Reducing Catheter-Associated Urinary Tract Infections Across a Hospital System Through Urine Culture Stewardship.

Objective: To evaluate the effectiveness and safety of an evidence-based urine culture stewardship program in reducing hospital catheter-associated urinary tract infections (CAUTIs) and the rate of CAUTIs across a 3-hospital system. Patients and Methods: This is a prospective, 2-year quality improvement program conducted from October 1, 2018, to September 30, 2020. An evidence-based urine culture stewardship program was designed, which consisted of the following: criteria for allowing or restricting urine cultures from catheterized patients, a best practice advisory integrated into the ordering system of an electronic medical record, and a systematic provider education and feedback program to ensure compliance. The system-wide rates of CAUTIs (total CAUTIs/catheter days×1000), changes in intercepts, trends, mortality, length of stay, rates of device utilization, and rates of hospital-onset sepsis were compared for 3 years before and 2 years after the launch of the program. Results: Catheter-associated urinary tract infections progressively decreased after the initiation of the program (B=-0.21, P=.001). When the trends before and after the initiation of the program were compared, there were no statistically significant increases in the ratio of actual to predicted hospital length of stay, intensive care unit length of stay, system-wide mortality, and intensive care unit mortality. Although the rates of hospital-acquired sepsis remained consistent after the implementation of the stewardship program through the first quarter of 2020, the rates showed an increase in the second and third quarters of 2020. However, hospital-onset sepsis events associated with the diagnosis of a urinary tract infection did not increase after the intervention. Conclusion: Urine culture stewardship is a safe and effective way to reduce CAUTIs among patients in a large multihospital health care system. Patient safety indicators appeared unchanged after the implementation of the program, and ongoing follow-up will improve confidence in the long-term sustainability of this strategy.

Tau Pathology Profile Across a Parietal-Hippocampal Brain Network Is Associated With Spatial Reorientation Learning and Memory Performance in the 3xTg-AD Mouse.

In early Alzheimer's disease (AD) spatial navigation is one of the first impairments to emerge; however, the precise cause of this impairment is unclear. Previously, we showed that, in a mouse model of tau and amyloid beta (Aß) aggregation, getting lost represents, at least in part, a failure to use distal cues to get oriented in space and that impaired parietal-hippocampal network level plasticity during sleep may underlie this spatial disorientation. However, the relationship between tau and amyloid beta aggregation in this brain network and impaired spatial orientation has not been assessed. Therefore, we used several approaches, including canonical correlation analysis and independent components analysis tools, to examine the relationship between pathology profile across the parietal-hippocampal brain network and spatial reorientation learning and memory performance. We found that consistent with the exclusive impairment in 3xTg-AD 6-month female mice, only 6-month female mice had an ICA identified pattern of tau pathology across the parietal-hippocampal network that were positively correlated with behavior. Specifically, a higher density of pTau positive cells predicted worse spatial learning and memory. Surprisingly, despite a lack of impairment relative to controls, 3-month female, as well as 6- and 12- month male mice all had patterns of tau pathology across the parietal-hippocampal brain network that are predictive of spatial learning and memory performance. However, the direction of the effect was opposite, a negative correlation, meaning that a higher density of pTau positive cells predicted better performance. Finally, there were not significant group or region differences in M78 density at any of the ages examined and ICA analyses were not able to identify any patterns of 6E10 staining across brain regions that were significant predictors of behavioral performance. Thus, the pattern of pTau staining across the parietal-hippocampal network is a strong predictor of spatial learning and memory performance, even for mice with low levels of tau accumulation and intact spatial re-orientation learning and memory. This suggests that AD may cause spatial disorientation as a result of early tau accumulation in the parietal-hippocampal network.

A qualitative assessment of emergency medicine residents' receptivity to feedback.

BACKGROUND: Effective feedback is the cornerstone of competency-based education. The emergency department (ED) is a unique learning and feedback environment. Developing our understanding of emergency medicine (EM) residents' experiences around feedback will improve resident training and inform EM faculty development programs. OBJECTIVE: This qualitative study explores the feedback culture and practices in EM and resident's experiences and attitudes toward feedback in this specific training environment. METHODS: At a large categorical EM program, 15 residents voluntarily participated in semistructured interviews regarding feedback. These individual interviews were performed by a nonphysician investigator and transcripts underwent an inductive multistep coding process. Transcripts were analyzed to identify common factors influencing feedback and then comparisons were made between residents to explore the interconnectedness of identified factors and further categorize consistent themes. RESULTS: Factors inherent to the ED environment make the delivery of effective feedback challenging. Residents also revealed that feedback-seeking/-avoidant behavior and receptivity to feedback are multifactorial. Residents actively seek feedback when they feel that they performed well but tend to avoid feedback interactions when they expect constructive feedback. Finally, residents filter feedback based on attending personality and perceived practice style as well as their own desired practice style. CONCLUSIONS: It is important for program leaders to understand their residents' experiences with feedback and engage both faculty and residents in conversations around feedback delivery and receptivity. An improved understanding of these experiences might also reveal barriers to performance assessment and guide efforts to improve the accuracy and reliability of resident evaluations.

Impaired Hippocampal-Cortical Interactions during Sleep in a Mouse Model of Alzheimer's Disease.

Spatial learning is impaired in humans with preclinical Alzheimer's disease (AD). We reported similar impairments in 3xTg-AD mice learning a spatial reorientation task. Memory reactivation during sleep is critical for learning-related plasticity, and memory consolidation is correlated with hippocampal sharp wave ripple (SWR) density, cortical delta waves (DWs), cortical spindles, and the temporal coupling of these events-postulated as physiological substrates for memory consolidation. Further, hippocampal-cortical discoordination is prevalent in individuals with AD. Thus, we hypothesized that impaired memory consolidation mechanisms in hippocampal-cortical networks could account for spatial memory deficits. We assessed sleep architecture, SWR-DW dynamics, and memory reactivation in a mouse model of tauopathy and amyloidosis implanted with a recording array targeting isocortex and hippocampus. Mice underwent daily recording sessions of rest-task-rest while learning the spatial reorientation task. We assessed memory reactivation by matching activity patterns from the approach to the unmarked reward zone to patterns during slow-wave sleep (SWS). AD mice had more SWS, but reduced SWR density. The increased SWS compensated for reduced SWR density so there was no reduction in SWR number. In control mice, spindles were phase-coupled with DWs, and hippocampal SWR-cortical DW coupling was strengthened in post-task sleep and was correlated with performance on the spatial reorientation task the following day. However, in AD mice, SWR-DW and spindle-DW coupling were impaired. Thus, reduced SWR-DW coupling may cause impaired learning in AD, and spindle-DW coupling during short rest-task-rest sessions may serve as a biomarker for early AD-related changes in these brain dynamics.

Visual outcomes after traumatic retrobulbar hemorrhage are not related to time or intraocular pressure.

BACKGROUND: The paucity of literature regarding the role of time and intraocular pressure (IOP) when treating ocular compartment syndrome (OCS) has resulted in limited guidance for emergency physicians (EP). OBJECTIVES: Our goals were to investigate the ideal time frame for lateral canthotomy, to understand the relationship between IOP and visual outcome, and to determine the impact of EP performance on visual acuity (VA). METHODS: The study population included patients presenting over an 18-year period with traumatic retrobulbar hemorrhage (RBH) treated with lateral canthotomy. Efficacy was evaluated using visual outcome and IOP. Patients were grouped by time from injury and arrival to canthotomy. Procedures completed in the emergency department (ED) and by EPs were evaluated regarding visual outcome. RESULTS: Sixty cases of RBH treated with lateral canthotomy were identified. Over two-thirds (43/60, 71.7%) were discharged with baseline vision. Lateral canthotomy lowered IOP from a median of 50.0 mmHg (IQR: 40.5, 61) preprocedure to 23.0 mmHg (IQR: 18, 27) post-procedure (p-value = 0.000001). No correlation was found between time, IOP, location, specialty of clinician, and visual outcome. CONCLUSION: Lateral canthotomy is an effective at lowering IOP. Our data suggest that using time and IOP to predict procedural outcome is flawed. If OCS is suspected, lateral canthotomy should be considered and can be effectively performed by EPs. Neither the time of injury to ED presentation nor degree of IOP elevation should be factored into the decision of when to perform the procedure.

Daily chlorohexidine gluconate bathing with impregnated cloths results in statistically significant reduction in central line-associated bloodstream infections.

BACKGROUND: Central line-associated bloodstream infections (CLABSI) contribute to increased morbidity, mortality, length of stay, and excessive cost of care. METHODS: This study was an observational cohort study using historical controls in the setting of a 9-bed surgical intensive care unit in a Level I trauma center; all patients admitted or transferred into the unit were enrolled in the study. OBJECTIVES: A quality improvement intervention protocol was instituted to reduce CLABSI incidence with a 3-month effectiveness study using 2% chlorhexidine gluconate-impregnated cloths for daily patient bathing; education of surgical intensive care unit staff on changes to CLABSI prevention protocol and all existing CLABSI prevention policies and bundles already in place; and compliance monitoring and documentation. RESULTS: The 3-month effectiveness study showed a decrease in CLABSI rates from 12.07 CLABSIs per 1000 central line-days to 3.17 CLABSIs per 1000 central line-days (73.7% rate reduction; P = .0358). CONCLUSION: CLABSI incidence rates were reduced in a high-risk patient population using evidence-based prevention bundles and implementing daily bathing with 2% chlorhexidine gluconate nonrinse cloths.