Development and National Validation of a Musculoskeletal Emergency Medicine Assessment Tool.

Introduction Musculoskeletal (MSK) complaints and injuries are the fourth most common primary diagnosis in the emergency department in the United States (US). Despite the prevalence and economic impact on the US healthcare system, new emergency medicine (EM) residency graduates report feeling unprepared to treat MSK complaints. Currently, there are no reported means to assess MSK knowledge in EM resident physicians. The purpose of this study is to develop a validated and peer-reviewed multiple-choice assessment tool focused on MSK knowledge relevant to EM to allow us to better assess the knowledge of resident physicians. Methods A group of EM/Sports Medicine subject-matter experts (SMEs) created an initial list of the most important MSK topics in EM to generate a relevant question bank. The questions were validated by a different group of SMEs using a three-round modified Delphi method to obtain consensus on the importance of each question. Based on these results, the assessment was formed. Results From a list of 99 MSK topics, SMEs developed a final list of 37 MSK topics relevant to EM. Following round one, free-marginal kappa was 0.58, 95% CI [0.50, 0.66], with a moderate overall agreement of 71.95%. Following round two, the calculated free-marginal kappa increased to 0.88, 95% CI [0.83, 0.92], with an overall agreement of 91.79%. Using a five-point Likert scale, a threshold of an average score less than four was used to exclude questions in round three of validation and to create a final 50-question assessment tool. Conclusion Our proposed exam, titled Musculoskeletal Emergency Medicine Assessment Tool (MEAT), was successfully validated by experts in our field. It evaluates clinically important topics and offers a tool for assessing MSK knowledge in EM resident physicians. Future studies are needed to determine the feasibility of administering the tool and to establish a baseline score among different populations within the practicing field of EM.

Whole organism snRNA-seq reveals systemic peripheral changes in Alzheimer's Disease fly models.

Peripheral tissues become disrupted in Alzheimer's Disease (AD). However, a comprehensive understanding of how the expression of AD-associated toxic proteins, Aß42 and Tau, in neurons impacts the periphery is lacking. Using Drosophila, a prime model organism for studying aging and neurodegeneration, we generated the Alzheimer's Disease Fly Cell Atlas (AD-FCA): whole-organism single-nucleus transcriptomes of 219 cell types from adult flies neuronally expressing human Aß42 or Tau. In-depth analyses and functional data reveal impacts on peripheral sensory neurons by Aß42 and on various non-neuronal peripheral tissues by Tau, including the gut, fat body, and reproductive system. This novel AD atlas provides valuable insights into potential biomarkers and the intricate interplay between the nervous system and peripheral tissues in response to AD-associated proteins.

Team Approach: Diagnosis, Management, and Prevention of Sudden Cardiac Arrest in the Athlete.

¼ Sudden cardiac events during sports competition are rare but tragic occurrences that require a timely, comprehensive response by well-prepared athletic trainers and medical providers. This sequence should prioritize prompt emergency medical system activation, immediate initiation of cardiopulmonary resuscitation (CPR), automated early defibrillation (AED), and comprehensive advanced life support efforts.¼ Exercise-induced cardiac remodeling, referred to as the "athlete's heart," refers to a host of adaptive changes that increase cardiac chamber size and wall thickness to allow for greater pressures and volumes during exercise. This remodeling phenotype may overlap with other inherited cardiomyopathies and cardiac abnormalities, which can complicate clinical care. The long-term implications of this electrical and structural remodeling on cardiac function are unknown.¼ Although the best screening strategies to optimize primary prevention of sudden cardiac arrest is an evolving topic, the effectiveness of CPR and early defibrillation use in treating out-of-hospital sudden cardiac arrest has been well-established, despite their reported underuse.

Aging Fly Cell Atlas identifies exhaustive aging features at cellular resolution.

Aging is characterized by a decline in tissue function, but the underlying changes at cellular resolution across the organism remain unclear. Here, we present the Aging Fly Cell Atlas, a single-nucleus transcriptomic map of the whole aging Drosophila. We characterized 163 distinct cell types and performed an in-depth analysis of changes in tissue cell composition, gene expression, and cell identities. We further developed aging clock models to predict fly age and show that ribosomal gene expression is a conserved predictive factor for age. Combining all aging features, we find distinctive cell type-specific aging patterns. This atlas provides a valuable resource for studying fundamental principles of aging in complex organisms.

Innate cocaine-seeking vulnerability arising from loss of serotonin-mediated aversive effects of cocaine in rats.

Cocaine blocks dopamine reuptake, thereby producing rewarding effects that are widely studied. However, cocaine also blocks serotonin uptake, which we show drives, in rats, individually variable aversive effects that depend on serotonin 2C receptors (5-HT2CRs) in the rostromedial tegmental nucleus (RMTg), a major GABAergic afferent to midbrain dopamine neurons. 5-HT2CRs produce depolarizing effects in RMTg neurons that are particularly strong in some rats, leading to aversive effects that reduce acquisition of and relapse to cocaine seeking. In contrast, 5-HT2CR signaling is largely lost after cocaine exposure in other rats, leading to reduced aversive effects and increased cocaine seeking. These results suggest a serotonergic biological marker of cocaine-seeking vulnerability that can be targeted to modulate drug seeking.

The role of neurotransmitter systems in mediating deep brain stimulation effects in Parkinson's disease.

Deep brain stimulation (DBS) is among the most successful paradigms in both translational and reverse translational neuroscience. DBS has developed into a standard treatment for movement disorders such as Parkinson's disease (PD) in recent decades, however, specific mechanisms behind DBS's efficacy and side effects remain unrevealed. Several hypotheses have been proposed, including neuronal firing rate and pattern theories that emphasize the impact of DBS on local circuitry but detail distant electrophysiological readouts to a lesser extent. Furthermore, ample preclinical and clinical evidence indicates that DBS influences neurotransmitter dynamics in PD, particularly the effects of subthalamic nucleus (STN) DBS on striatal dopaminergic and glutamatergic systems; pallidum DBS on striatal dopaminergic and GABAergic systems; pedunculopontine nucleus DBS on cholinergic systems; and STN-DBS on locus coeruleus (LC) noradrenergic system. DBS has additionally been associated with mood-related side effects within brainstem serotoninergic systems in response to STN-DBS. Still, addressing the mechanisms of DBS on neurotransmitters' dynamics is commonly overlooked due to its practical difficulties in monitoring real-time changes in remote areas. Given that electrical stimulation alters neurotransmitter release in local and remote regions, it eventually exhibits changes in specific neuronal functions. Consequently, such changes lead to further modulation, synthesis, and release of neurotransmitters. This narrative review discusses the main neurotransmitter dynamics in PD and their role in mediating DBS effects from preclinical and clinical data.

Stability and Dissociation of Adeno-Associated Viral Capsids by Variable Temperature-Charge Detection-Mass Spectrometry.

Adeno-associated viral (AAV) vectors have emerged as gene therapy and vaccine delivery systems. Differential scanning fluorimetry or differential scanning calorimetry is commonly used to measure the thermal stability of AAVs, but these global methods are unable to distinguish the stabilities of different AAV subpopulations in the same sample. To address this challenge, we combined charge detection-mass spectrometry (CD-MS) with a variable temperature (VT) electrospray source that controls the temperature of the solution prior to electrospray. Using VT-CD-MS, we measured the thermal stabilities of empty and filled capsids. We found that filled AAVs ejected their cargo first and formed intermediate empty capsids before completely dissociating. Finally, we observed that pH stress caused a major decrease in thermal stability. This new approach better characterizes the thermal dissociation of AAVs, providing the simultaneous measurement of the stabilities and dissociation pathways of different subpopulations.

Black eye syndrome and a systemic rickettsia-like organism in Alaskan Chionoecetes spp. crabs, including normal eyestalk microanatomy.

A black eye syndrome (BES) was discovered in both captive and wild populations of Alaskan snow crabs Chionoecetes opilio and Tanner crabs C. bairdi. Field prevalences ranged from 0.37% (n = 594/161295) to 19.6% (n = 62/316) in snow crabs from the eastern Bering Sea and from 0.09% (n = 15/16638) to 0.7% (n = 133/18473) in Tanner crabs from the same trawl samples, with a slightly greater percentage (1.4%, n = 57/3945) in Tanner crabs from the Aleutian and Kodiak islands fisheries in the Gulf of Alaska. BES is not associated with crab mortality and has 2 distinct manifestations: abnormal black foci of internal eye pigment with no discernible histological lesions, which, in many cases, is followed by corneal shell disease with ulceration and distal eyestalk erosion. It is assumed for this study that these are early and late stages of BES that are somehow related. Our results suggest that early stages of abnormal pigmentation are noninfectious, possibly related to changing ocean conditions affecting crab endocrinology and neuropeptide control of secondary eye pigment. Potential light-induced photoreceptor damage of harvested crabs with dark-adapted eyes is another anthropogenic factor possibly contributing to the early changes in eye pigmentation. Normal eyestalk microanatomy specific for Chionoecetes spp. is provided as necessary baseline information for future studies. Early in the study, an unreported rickettsia-like organism (RLO) was discovered infecting dissected black eyestalks submitted for examination from 5 of 6 dead snow crabs, suggesting association with BES. Subsequent samples indicated the RLO was systemic, infected both black and normal-appearing eyestalks, and was unrelated to BES. However, the multiorgan infection and histopathology indicated the RLO could be a primary pathogen of snow crabs.

Kissing Viabahn VBX stent graft reconstruction of thoracic central veins for management of superior vena cava syndrome.

OBJECTIVE: In the present study, we evaluated the technical and clinical outcomes of thoracic central vein reconstruction for superior vena cava (SVC) syndrome using kissing Viabahn VBX stent grafts (W.L. Gore & Associates, Flagstaff, AZ). METHODS: All adult patients with SVC syndrome who had undergone attempted bilateral brachiocephalic vein-to-SVC reconstruction using kissing VBX stent grafts at an academic hospital between August 2019 and February 2021 were reviewed. The technical results, adverse events, imaging follow-up findings, and clinical outcomes were recorded. Patency over time was assessed using Kaplan-Meier analysis. RESULTS: A total of 28 patients (16 women and 12 men; mean age, 52.0 years) constituted the study cohort. Of the 28 patients, 17 (60.7%) had had benign and 11 (39.3%) malignant etiologies. The presenting symptoms included neck swelling (n = 17; 60.7%), bilateral upper extremity swelling (n = 15; 53.6%), dyspnea (n = 7; 25%), unilateral upper extremity swelling (n = 4; 14.3%), and dysphagia (n = 1; 3.6%). SVC reconstruction with VBX stent grafts in a kissing configuration was successfully completed in 27 of the 28 patients (96.4%). Four major adverse events were noted in the benign etiology subgroup (23.5%), including intraprocedural hemopericardium (n = 3) and delayed pneumothorax (n = 1). Of the 28 patients, 27 (96.4%) had experienced resolution of their presenting symptoms. The mean clinical follow-up for the living patients was 358.8 ± 77.2 days (range, 78-645 days). The mean imaging follow-up for the living patients was 272.6 ± 91 days (range, 26-594 days). The primary, primary-assisted, and secondary patency rates at 12 months were 71.8%, 88.8%, and 100%, respectively. CONCLUSIONS: For the management of SVC syndrome, thoracic central vein reconstruction with kissing VBX stent grafts was feasible with a high rate of symptom resolution and acceptable patency. However, this technique should not be recommended for those with benign SVC syndrome owing to the high risk of cardiac tamponade.

Nigral neuropathology of Parkinson's motor subtypes coincide with circuitopathies: a scoping review.

The neuropathological substrates of Parkinson's disease (PD) patients with motor subtypes tremor-dominance (TD), non-tremor dominance (nTD), postural instability and gait difficulty (PIGD), and akinetic-rigid (AR) are not completely differentiated. While extensive pathological research has been conducted on neuronal tissue of PD patients, data have not been discussed in the context of mechanistic circuitry theories differentiating motor subtypes. It is, therefore, expected that a more specific and tailored management of PD symptoms can be accomplished by understanding symptom-specific neuropathological mechanisms with the detail histology can provide. This scoping review gives an overview of the literature comparing TD and nTD PD motor subtypes by clarify observed pathology with underlying physiological circuitry theories. Studies using an array of pathological examination techniques have shown significant differences between TD and nTD PD subtypes. nTD PD patients show higher neuronal loss, gliosis, extraneuronal melanin deposits, and neuroaxonal dystrophy in multiple subregions of the substantia nigra (SN) related to the overactivity of the indirect motor loop. TD patients show more severe cell loss specifically in medial SN subdivisions, and have damage in the retrorubral field A-8 that projects to the dorsolateral striatum and ventromedial thalamus in the direct motor loop. Pathological studies are consistent with neuroimaging data and support contemporary mechanistic circuitry theories of PD motor symptom genesis. Further multimodal neuroimaging and histological studies are required to validate and expand upon these findings.

Migrating bubble synthesis promotes mutagenesis through lesions in its template.

Break-induced replication (BIR) proceeds via a migrating D-loop for hundreds of kilobases and is highly mutagenic. Previous studies identified long single-stranded (ss) nascent DNA that accumulates during leading strand synthesis to be a target for DNA damage and a primary source of BIR-induced mutagenesis. Here, we describe a new important source of mutagenic ssDNA formed during BIR: the ssDNA template for leading strand BIR synthesis formed during D-loop migration. Specifically, we demonstrate that this D-loop bottom template strand (D-BTS) is susceptible to APOBEC3A (A3A)-induced DNA lesions leading to mutations associated with BIR. Also, we demonstrate that BIR-associated ssDNA promotes an additional type of genetic instability: replication slippage between microhomologies stimulated by inverted DNA repeats. Based on our results we propose that these events are stimulated by both known sources of ssDNA formed during BIR, nascent DNA formed by leading strand synthesis, and the D-BTS that we describe here. Together we report a new source of mutagenesis during BIR that may also be shared by other homologous recombination pathways driven by D-loop repair synthesis.

Cancer cells are highly susceptible to accumulation of templated insertions linked to MMBIR.

Microhomology-mediated break-induced replication (MMBIR) is a DNA repair pathway initiated by polymerase template switching at microhomology, which can produce templated insertions that initiate chromosomal rearrangements leading to neurological and metabolic diseases, and promote complex genomic rearrangements (CGRs) found in cancer. Yet, how often templated insertions accumulate from processes like MMBIR in genomes is poorly understood due to difficulty in directly identifying these events by whole genome sequencing (WGS). Here, by using our newly developed MMBSearch software, we directly detect such templated insertions (MMB-TIs) in human genomes and report substantial differences in frequency and complexity of MMB-TI events between normal and cancer cells. Through analysis of 71 cancer genomes from The Cancer Genome Atlas (TCGA), we observed that MMB-TIs readily accumulate de novo across several cancer types, with particularly high accumulation in some breast and lung cancers. By contrast, MMB-TIs appear only as germline variants in normal human fibroblast cells, and do not accumulate as de novo somatic mutations. Finally, we performed WGS on a lung adenocarcinoma patient case and confirmed MMB-TI-initiated chromosome fusions that disrupted potential tumor suppressors and induced chromothripsis-like CGRs. Based on our findings we propose that MMB-TIs represent a trigger for widespread genomic instability and tumor evolution.

Dedicated container for postmortem human brain ultra-high field magnetic resonance imaging.

BACKGROUND: The emerging field of ultra-high field MRI (UHF-MRI, 7 Tesla and higher) provides the opportunity to image human brains at a higher resolution and with higher signal-to-noise ratios compared to the more widely available 1.5 and 3T scanners. Scanning postmortem tissue additionally allows for greatly increased scan times and fewer movement issues leading to improvements in image quality. However, typical postmortem neuroimaging routines involve placing the tissue within plastic bags that leave room for susceptibility artifacts from tissue-air interfaces, inadequate submersion, and leakage issues. To address these challenges in postmortem imaging, a custom-built nonferromagnetic container was developed that allows whole brain hemispheres to be scanned at sub-millimeter resolution within typical head-coils. METHOD: The custom-built polymethylmethacrylaat container consists of a cylinder with a hemispheric side and a lid with valves on the adjacent side. This shape fits within common MR head-coils and allows whole hemispheres to be submerged and vacuum sealed within it reducing imaging artifacts that would otherwise arise at air-tissue boundaries. Two hemisphere samples were scanned on a Siemens 9.4T Magnetom MRI scanner. High resolution T2* weighted data was obtained with a custom 3D gradient echo (GRE) sequence and diffusion-weighted imaging (DWI) scans were obtained with a 3D kT-dSTEAM sequence along 48 directions. RESULTS: The custom-built container proved to submerge and contain tissue samples effectively and showed no interferences with MR scanning acquisition. The 3D GRE sequence provided high resolution isotropic T2* weighted data at 250 µm which showed a clear visualization of gray and white matter structures. DWI scans allowed for dense reconstruction of structural white matter connections via tractography. CONCLUSION: Using this custom-built container worked towards achieving high quality MR images of postmortem brain material. This procedure can have advantages over traditional schemes including utilization of a standardized protocol and the reduced likelihood of leakage. This methodology could be adjusted and used to improve typical postmortem imaging routines.

Neuroimaging Detectable Differences between Parkinson's Disease Motor Subtypes: A Systematic Review.

BACKGROUND: The neuroanatomical substrates of Parkinson's disease (PD) with tremor-dominance (TD) and those with non-tremor dominance (nTD), postural instability and gait difficulty (PIGD), and akinetic-rigid (AR) are not fully differentiated. A better understanding of symptom specific pathoanatomical markers of PD subtypes may result in earlier diagnosis and more tailored treatment. Here, we aim to give an overview of the neuroimaging literature that compared PD motor subtypes. METHODS: A systematic literature review on neuroimaging studies of PD subtypes was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Search terms submitted to the PubMed database included: "Parkinson's disease", "MRI" and "motor subtypes" (TD, nTD, PIGD, AR). The results are first discussed from macro to micro level of organization (i.e., (1) structural; (2) functional; and (3) molecular) and then by applied imaging methodology. FINDINGS: Several neuroimaging methods including diffusion imaging and positron emission tomography (PET) distinguish specific PD motor subtypes well, although findings are mixed. Furthermore, our review demonstrates that nTD-PD patients have more severe neuroalterations compared to TD-PD patients. More specifically, nTD-PD patients have deficits within striato-thalamo-cortical (STC) circuitry and other thalamocortical projections related to cognitive and sensorimotor function, while TD-PD patients tend to have greater cerebello-thalamo-cortical (CTC) circuitry dysfunction. CONCLUSIONS: Based on the literature, STC and CTC circuitry deficits seem to be the key features of PD and the subtypes. Future research should make greater use of multimodal neuroimaging and techniques that have higher sensitivity in delineating subcortical structures involved in motor diseases.

Biological batch normalisation: How intrinsic plasticity improves learning in deep neural networks.

In this work, we present a local intrinsic rule that we developed, dubbed IP, inspired by the Infomax rule. Like Infomax, this rule works by controlling the gain and bias of a neuron to regulate its rate of fire. We discuss the biological plausibility of the IP rule and compare it to batch normalisation. We demonstrate that the IP rule improves learning in deep networks, and provides networks with considerable robustness to increases in synaptic learning rates. We also sample the error gradients during learning and show that the IP rule substantially increases the size of the gradients over the course of learning. This suggests that the IP rule solves the vanishing gradient problem. Supplementary analysis is provided to derive the equilibrium solutions that the neuronal gain and bias converge to using our IP rule. An analysis demonstrates that the IP rule results in neuronal information potential similar to that of Infomax, when tested on a fixed input distribution. We also show that batch normalisation also improves information potential, suggesting that this may be a cause for the efficacy of batch normalisation-an open problem at the time of this writing.

Evidence for interannual variation in genetic structure of Dungeness crab (Cancer magister) along the California Current System.

Using a combination of population- and individual-based analytical approaches, we provide a comprehensive examination of genetic connectivity of Dungeness crab (Cancer magister) along ~1,200 km of the California Current System (CCS). We sampled individuals at 33 sites in 2012 to establish a baseline of genetic diversity and hierarchal population genetic structure and then assessed interannual variability in our estimates by sampling again in 2014. Genetic diversity showed little variation among sites or across years. In 2012, we observed weak genetic differentiation among sites (FST range = -0.005-0.014) following a pattern of isolation by distance (IBD) and significantly high relatedness among individuals within nine sampling sites. In 2014, pairwise FST estimates were lower (FST range = -0.014-0.007), there was no spatial autocorrelation, and fewer sites had significant evidence of relatedness. Based on these findings, we propose that interannual variation in the physical oceanographic conditions of the CCS influences larval recruitment and thus gene flow, contributing to interannual variation in population genetic structure. Estimates of effective population size (Ne ) were large in both 2012 and 2014. Together, our results suggest that Dungeness crab in the CCS may constitute a single evolutionary population, although geographically limited dispersal results in an ephemeral signal of IBD. Furthermore, our findings demonstrate that populations of marine organisms may be susceptible to temporal changes in population genetic structure over short time periods; thus, interannual variability in population genetic measures should be considered.

Application of NMR-based metabolomics for environmental assessment in the Great Lakes using zebra mussel (Dreissena polymorpha).

Zebra mussel, Dreissena polymorpha, in the Great Lakes is being monitored as a bio-indicator organism for environmental health effects by the National Oceanic and Atmospheric Administration's Mussel Watch program. In order to monitor the environmental effects of industrial pollution on the ecosystem, invasive zebra mussels were collected from four stations-three inner harbor sites (LMMB4, LMMB1, and LMMB) in Milwaukee Estuary, and one reference site (LMMB5) in Lake Michigan, Wisconsin. Nuclear magnetic resonance (NMR)-based metabolomics was used to evaluate the metabolic profiles of the mussels from these four sites. The objective was to observe whether there were differences in metabolite profiles between impacted sites and the reference site; and if there were metabolic profile differences among the impacted sites. Principal component analyses indicated there was no significant difference between two impacted sites: north Milwaukee harbor (LMMB and LMMB4) and the LMMB5 reference site. However, significant metabolic differences were observed between the impacted site on the south Milwaukee harbor (LMMB1) and the LMMB5 reference site, a finding that correlates with preliminary sediment toxicity results. A total of 26 altered metabolites (including two unidentified peaks) were successfully identified in a comparison of zebra mussels from the LMMB1 site and LMMB5 reference site. The application of both uni- and multivariate analysis not only confirmed the variability of altered metabolites but also ensured that these metabolites were identified via unbiased analysis. This study has demonstrated the feasibility of the NMR-based metabolomics approach to assess whole-body metabolomics of zebra mussels to study the physiological impact of toxicant exposure at field sites.