Matriglycan maintains t-tubule structural integrity in cardiac muscle.

Maintaining the structure of cardiac membranes and membrane organelles is essential for heart function. A critical cardiac membrane organelle is the transverse tubule system (called the t-tubule system) which is an invagination of the surface membrane. A unique structural characteristic of the cardiac muscle t-tubule system is the extension of the extracellular matrix (ECM) from the surface membrane into the t-tubule lumen. However, the importance of the ECM extending into the cardiac t-tubule lumen is not well understood. Dystroglycan (DG) is an ECM receptor in the surface membrane of many cells, and it is also expressed in t-tubules in cardiac muscle. Extensive posttranslational processing and O-glycosylation are required for DG to bind ECM proteins and the binding is mediated by a glycan structure known as matriglycan. Genetic disruption resulting in defective O-glycosylation of DG results in muscular dystrophy with cardiorespiratory pathophysiology. Here, we show that DG is essential for maintaining cardiac t-tubule structural integrity. Mice with defects in O-glycosylation of DG developed normal t-tubules but were susceptible to stress-induced t-tubule loss or severing that contributed to cardiac dysfunction and disease progression. Finally, we observed similar stress-induced cardiac t-tubule disruption in a cohort of mice that solely lacked matriglycan. Collectively, our data indicate that DG in t-tubules anchors the luminal ECM to the t-tubule membrane via the polysaccharide matriglycan, which is critical to transmitting structural strength of the ECM to the t-tubules and provides resistance to mechanical stress, ultimately preventing disruptions in cardiac t-tubule integrity.

Evidence to support health system prioritization of health behaviors in the COVID-19 era.

BACKGROUND: Since the COVID-19 pandemic health systems have shifted necessarily from chronic to infectious disease treatment, but chronic disease remains critical. One large health system uniquely tracks member health behaviors. This analysis compares data from select months of an ongoing monthly cross-sectional survey before and during the pandemic. METHODS: Responses in April 2019 (pre-pandemic), April 2020 (early pandemic) or April 2021 (later pandemic) were included in the primary analysis (N = 252). Differences in meeting health behavior guidelines were analyzed via logistic regression. RESULTS: A significant decline was seen for physical activity (19% not meeting guidelines pre-pandemic vs. 41% later pandemic) but not fruit/vegetable, alcohol, or sleep from early to later pandemic. Prevalence of women not meeting tobacco guidelines increased from early (5%) to later pandemic (10%) while prevalence in men decreased (10% vs 4% respectively). The percent of people not thinking about the good things that happen to them fluctuated closely with reports of new COVID-19 cases. CONCLUSIONS: Findings show the nuance of changing health behaviors throughout the pandemic. Results should be used by health systems to tailor support based on insights from the pandemic experience.

A pilot trial of a brief intervention for cannabis use supplemented with a substance-free activity session or relaxation training.

OBJECTIVE: Cannabis use is increasing among college students and commonly co-occurs with anxiety symptoms in this age group. Interventions that reduce anxiety may also reduce cannabis use. Behavioral economic theory suggests that substance use reductions are most likely when there is an increase in substance-free reinforcement. This randomized pilot trial evaluated the efficacy of a brief motivational intervention (BMI) for cannabis supplemented by either a substance-free activity session (SFAS) or a relaxation training (RT) session for reducing cannabis use, problems, craving, and anxiety symptoms. METHOD: One hundred thirty-two college students (Mage = 19.9; 54% female; 67% White, 31% Black) who reported five or more past-month cannabis use days were randomized to: (a) assessment-only (AO); (b) BMI plus SFAS; or (c) BMI plus RT. Participants in the BMI conditions received two individual counselor-administered sessions plus a brief phone booster session. Outcomes were evaluated 1- and 6-months postintervention. RESULTS: Relative to assessment, both BMI + SFAS and BMI + RT were associated with significant reductions in cannabis problems and craving at 1-month follow-up, and significant reductions in anxiety at 6-month follow-up. Relative to AO, BMI + RT was associated with significant reductions in cannabis use at 1-month follow-up. There were no differences between BMI conditions. CONCLUSIONS: This pilot trial was not adequately powered to conclusively evaluate relative efficacy but provides preliminary support for the short-term efficacy of both two-session interventions for reducing anxiety and cannabis-related risk among nontreatment seeking emerging adults. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Penile Strangulation: Analysis of Postextrication Follow-Up, Sequelae, and a Review of Literature.

Numerous case reports exist on penile strangulation injuries and extrication methods; however, the care and long-term consequences of penile strangulation injuries have been under-reported. Our aim is to investigate the long-term outcomes and sequalae following penile strangulation injuries. The PubMed Medline database was searched using the keyword string "penile strangulation," "penis strangulation," and "constriction" for all studies reporting outcomes of published penile strangulation injuries. Articles were evaluated for follow-up after strangulation injury, strangulating agent, extricating agent, and sequelae of injury. Fifty-six studies resulted with reports of 100 cases of penile strangulation and extrication from January 2000 to December 2019. The mean patient age was 41 (range: 3-86) years. Twenty-four (24/100) cases reported sequalae following extrication. Follow-up ranged from 2 weeks to 7 years with median follow-up time in the 7- to 12-month grouping. Metal rings comprised 36% (36/100) of strangulation agents and 50% of reported incidents were attributed to sexual activity. To our knowledge, this is the only study focusing on long-term outcomes after penile strangulation. This review provides a summary of 56 studies that document penile strangulation injuries over the last 20 years. Although a wide array of penile strangulation injuries have been documented in the literature, reports lack secondary management and long-term outcomes after removal of the strangulation device. We recommend that providers report long-term penile strangulation outcomes for future urologic evaluations after extrication.

Reporting and impact of subsequent cycle toxicities in oncology phase I clinical trials.

BACKGROUND/AIMS: As oncology treatments evolve, classic assumptions of toxicity associated with cytotoxic agents may be less relevant, requiring new design strategies for trials intended to inform dosing strategies for agents that may be administered beyond a set number of defined cycles. We describe the overall incidence of dose-limiting toxicities during and after cycle 1, frequency of reporting subsequent cycle toxicities, and the impact of post-cycle 1 dose-limiting toxicities on conclusions drawn from oncology phase 1 clinical trials. METHODS: We conducted a systematic review of subsequent cycle toxicities in oncology phase I clinical trials published in the Journal of Clinical Oncology from 2000 to 2020. We used chi-square tests and multivariate logistic regression to describe predictors of reporting subsequent cycle toxicity data. RESULTS: From 2000 to 2020, we identified 489 articles reporting on therapeutic phase 1 clinical trials. Of these, 421 (86%) reported data regarding cycle 1 dose-limiting toxicities and 170 (35%) reported data on cycle 1 dose modifications. Of the trials that reported cycle 1 dose-limiting toxicities, the median percentage of patients that experienced cycle 1 dose-limiting toxicities was 8.89%. Only 47 (9.6%) publications reported on post-cycle 1 dose-limiting toxicities and only 92 (19%) reported on dose modifications beyond cycle 1. Of the trials that reported post-cycle 1 dose-limiting toxicities, the median percentage of patients that experienced post-cycle 1 dose-limiting toxicities was 14.8%. Among the 371 studies with a recommended phase 2 dose, 89% did not report whether post-cycle 1 toxicities impacted the recommended phase 2 dose. More recent year of publication was independently associated with reduced odds of reporting subsequent cycle toxicity. CONCLUSION: Reporting of subsequent cycle toxicity is uncommon in oncology phase I clinical trial publications and becoming less common over time. Guidelines for reporting of phase I oncology clinical trials should expand to include toxicity data beyond the first cycle.

A comprehensive analysis of neuroblastoma incidence, survival, and racial and ethnic disparities from 2001 to 2019.

BACKGROUND: We characterize the incidence and 5-year survival of children and adolescents with neuroblastoma stratified by demographic and clinical factors based on the comprehensive data from United States Cancer Statistics (USCS) and the National Program of Cancer Registries (NPCR). METHODS: We analyzed the incidence of neuroblastoma from USCS (2003-2019) and survival data from NPCR (2001-2018) for patients less than 20 years old. Incidence trends were calculated by average annual percent change (AAPC) using joinpoint regression. Differences in relative survival were estimated comparing non-overlapping confidence intervals (CI). RESULTS: We identified 11,543 primary neuroblastoma cases in USCS. Age-adjusted incidence was 8.3 per million persons [95% CI: 8.2, 8.5], with an AAPC of 0.4% [95% CI: -0.1, 0.9]. Five-year relative survival from the NPCR dataset (n = 10,676) was 79.7% [95% CI: 78.9, 80.5]. Patients aged less than 1 year had the highest 5-year relative survival (92.5%). Five-year relative survival was higher for non-Hispanic White patients (80.7%) or Hispanic patients (80.8%) compared to non-Hispanic Black patients (72.6%). CONCLUSION: Neuroblastoma incidence was stable during 2003-2019. Differences in relative survival exist by sex, age, race/ethnicity, and stage; patients who were male, older, non-Hispanic Black, or with distant disease had worse survival. Future studies could seek to assess the upstream factors driving disparities in survival, and evaluate interventions to address inequities and improve survival across all groups.

Deafening Silence of Male Infertility.

Think about 6 loved ones of reproductive age in your life. Now imagine that 1 of these 6 individuals is suffering from infertility. Perhaps they feel alone and isolated, unable to discuss their heartbreak with their closest friends, family, and support network. Suffering in silence. In this editorial, we discuss the infertility journey through the lens of the patients, the providers, and the scientists who struggle with infertility each and every day. Our goal is to open a dialogue surrounding infertility, with an emphasis on dismantling the longstanding societal barriers to acknowledging male infertility as a disease. Through education, communication, compassion, and advocacy, together we can all begin to break the deafening silence of male infertility.

Deep Mutational Scanning in Disease-related Genes with Saturation Mutagenesis-Reinforced Functional Assays (SMuRF).

Interpretation of disease-causing genetic variants remains a challenge in human genetics. Current costs and complexity of deep mutational scanning methods hamper crowd-sourcing approaches toward genome-wide resolution of variants in disease-related genes. Our framework, Saturation Mutagenesis-Reinforced Functional assays (SMuRF), addresses these issues by offering simple and cost-effective saturation mutagenesis, as well as streamlining functional assays to enhance the interpretation of unresolved variants. Applying SMuRF to neuromuscular disease genes FKRP and LARGE1, we generated functional scores for over 99.8% of all possible coding single nucleotide variants and resolved 310 clinically reported variants of uncertain significance with high confidence, enhancing clinical variant interpretation in dystroglycanopathies. SMuRF also demonstrates utility in predicting disease severity, resolving critical structural regions, and providing training datasets for the development of computational predictors. Our approach opens new directions for enabling variant-to-function insights for disease genes in a manner that is broadly useful for crowd-sourcing implementation across standard research laboratories.

Identification of Matriglycan by Dual Exoglycosidase Digestion of α-Dystroglycan.

Matriglycan is a linear polysaccharide of alternating xylose and glucuronic acid units [-Xyl-α1,3-GlcA-ß1,3]n that is uniquely synthesized on α-dystroglycan (α-DG) and is essential for neuromuscular function and brain development. It binds several extracellular matrix proteins that contain laminin-globular domains and is a receptor for Old World arenaviruses such as Lassa Fever virus. Monoclonal antibodies such as IIH6 are commonly used to detect matriglycan on α-DG. However, endogenous expression levels are not sufficient to detect and analyze matriglycan by mass spectrometry approaches. Thus, there is a growing need to independently confirm the presence of matriglycan on α-DG and possibly other proteins. We used an enzymatic approach to detect matriglycan, which involved digesting it with two thermophilic exoglycosidases: ß-Glucuronidase from Thermotoga maritima and α-xylosidase from Sulfolobus solfataricus. This allowed us to identify and categorize matriglycan on α-DG by studying post-digestion changes in the molecular weight of α-DG using SDS-PAGE followed by western blotting with anti-matriglycan antibodies, anti-core α-DG antibodies, and/or laminin binding assay. In some tissues, matriglycan is capped by a sulfate group, which renders it resistant to digestion by these dual exoglycosidases. Thus, this method can be used to determine the capping status of matriglycan. To date, matriglycan has only been identified on vertebrate α-DG. We anticipate that this method will facilitate the discovery of matriglycan on α-DG in other species and possibly on other proteins. Key features • Analysis of endogenous matriglycan on dystroglycan from any animal tissue. • Matriglycan is digested using thermophilic enzymes, which require optimum thermophilic conditions. • Western blotting is used to assay the success and extent of digestion. • Freshly purified enzymes work best to digest matriglycan.

Phase 1 study of cabozantinib in combination with topotecan-cyclophosphamide for patients with relapsed Ewing sarcoma or osteosarcoma.

PURPOSE: Phase 1 study assessing the safety and toxicity of cabozantinib in combination with topotecan and cyclophosphamide for relapsed osteosarcoma and Ewing sarcoma. METHODS: Oral cabozantinib (25 mg/m2 ) was administered daily for 21 (dose level 1) or 14 (dose level -1B) days. Topotecan (0.75 mg/m2 ) and cyclophosphamide (250 mg/m2 ) were administered intravenously (IV) on days 1-5. A modified 3+3 design based upon first cycle dose-limiting toxicities (DLT) was used for dose escalation. RESULTS: Twelve patients with a median age of 15 (12.9-33.2) years were enrolled (seven with Ewing sarcoma; five with osteosarcoma); all were evaluable for toxicity. At dose level 1, three of six patients developed first cycle DLT: grade 3 epistaxis, grade 3 transaminitis, and prolonged grade 2 thrombocytopenia. Six patients were enrolled on dose level -1B (interrupted cabozantinib, given days 8-21), with one first cycle DLT (grade 3 pneumothorax) observed. Of the 10 response evaluable patients, one had partial response (Ewing sarcoma), seven had stable disease, and two had progressive disease. CONCLUSIONS: The recommended phase 2 doses and schedules for this combination are topotecan 0.75 mg/m2 IV days 1-5, cyclophosphamide 250 mg/m2 IV days 1-5, and cabozantinib 25 mg/m2 days 8-21. Non-concomitant administration of cabozantinib with cytotoxic therapy in this population has acceptable toxicity, while allowing for potential disease control.

Predictors of Stigma, Guilt, and Shame among Adults Bereaved by Fatal Overdose.

With the spectacular rise of US overdose deaths, bereavement for these affected families has become a matter of increasing concern. Qualitative research has highlighted the role of stigmatization as well as guilt and shame among this population. However, the magnitude and pre-death predictors of stigmatization, guilt, and shame have yet to be assessed quantitatively. In the current study, we assess the magnitude of stigmatization, guilt, and shame among 115 adults bereaved by overdose by drawing comparisons with 185 adults bereaved by suicide. Results revealed no significant differences regarding overall levels of stigmatization, guilt, and shame between the overdose and suicide bereaved. Among the overdose bereaved, regression models indicated a number of pre-death factors associated with stigmatization, guilt, and shame, such as the frequency of the decedent's drug use, family drug use severity, and interpersonal conflict between the bereaved and the decedent. Implications and future directions for research are discussed.

Evolution of an extreme hemoglobin phenotype contributed to the sub-Arctic specialization of extinct Steller's sea cows.

The extinct Steller's sea cow (Hydrodamalis gigas; †1768) was a whale-sized marine mammal that manifested profound morphological specializations to exploit the harsh coastal climate of the North Pacific. Yet despite first-hand accounts of their biology, little is known regarding the physiological adjustments underlying their evolution to this environment. Here, the adult-expressed hemoglobin (Hb; α2ß/δ2) of this sirenian is shown to harbor a fixed amino acid replacement at an otherwise invariant position (ß/δ82Lys→Asn) that alters multiple aspects of Hb function. First, our functional characterization of recombinant sirenian Hb proteins demonstrates that the Hb-O2 affinity of this sub-Arctic species was less affected by temperature than those of living (sub)tropical sea cows. This phenotype presumably safeguarded O2 delivery to cool peripheral tissues and largely arises from a reduced intrinsic temperature sensitivity of the H. gigas protein. Additional experiments on H. gigas ß/δ82Asn→Lys mutant Hb further reveal this exchange renders Steller's sea cow Hb unresponsive to the potent intraerythrocytic allosteric effector 2,3-diphosphoglycerate, a radical modification that is the first documented example of this phenotype among mammals. Notably, ß/δ82Lys→Asn moreover underlies the secondary evolution of a reduced blood-O2 affinity phenotype that would have promoted heightened tissue and maternal/fetal O2 delivery. This conclusion is bolstered by analyses of two Steller's sea cow prenatal Hb proteins (Hb Gower I; ζ2ε2 and HbF; α2γ2) that suggest an exclusive embryonic stage expression pattern, and reveal uncommon replacements in H. gigas HbF (γ38Thr→Ile and γ101Glu→Asp) that increased Hb-O2 affinity relative to dugong HbF. Finally, the ß/δ82Lys→Asn replacement of the adult/fetal protein is shown to increase protein solubility, which may have elevated red blood cell Hb content within both the adult and fetal circulations and contributed to meeting the elevated metabolic (thermoregulatory) requirements and fetal growth rates associated with this species cold adaptation.

In 1741, shipwrecked naturalist Georg Wilhelm Steller made detailed observations of large marine mammals grazing on seaweed in the shallow waters surrounding a remote island in the North Pacific Ocean. Within thirty years, these 'Steller's sea cows' had been hunted to extinction. Unlike their remaining tropical relatives ­ dugongs and manatees ­ Steller's sea cows were specialized to cold, sub-Arctic environments. Measuring up to 10 meters long, they were much larger than other sea cow species. This, along with having very thick skin, helped them to reduce heat loss. Previous work showed that the hemoglobin protein ­ which binds to and carries oxygen around mammalian bodies ­ of Steller's sea cows had a decreased affinity for oxygen, resulting in greater delivery of oxygen to organs and tissues. It was thought that this could be an adaptation to fuel heightened metabolic heat production in cold conditions. Studies of ancient DNA also identified the substitution of a single building block in the Steller's sea cow hemoglobin protein that is not present in other mammals and was suspected to underlie this modification. To determine how this unique substitution affects Steller's sea cow hemoglobin function ­ and whether it contributed to their ability to live in cold environments ­ Signore et al. generated hemoglobin proteins of Steller's sea cows, dugongs and Florida manatees. Testing their biochemical properties showed that this single exchange profoundly alters multiple aspects of how the Steller's sea cow hemoglobin works. Alongside reducing hemoglobin's oxygen affinity, the Steller's sea cow substitution also makes the protein more soluble, potentially increasing the level of hemoglobin within red blood cells. Additionally, it eliminates hemoglobin sensitivity to a molecule involved in oxygen binding ­ known as DPG ­ saving energy by no longer requiring production of this molecule. Furthermore, the same substitution makes hemoglobin less sensitive to changes in temperature, which would have helped to safeguard the delivery of oxygen to cool limbs and other extremities, reducing costly heat loss. Together, these changes in hemoglobin would have helped the Steller's sea cow to more efficiently transport oxygen around the body. Importantly, generating and testing Steller's sea cow pre-natal hemoglobins suggested this substitution may have also helped to enhance the fetal growth rate of these immense marine mammals by improving gas exchange between the mother and fetus. Signore et al. have revealed how a mutated form of hemoglobin allowed an extinct mammal to adapt to an extreme environment. Similar methods could be used to understand the physiological attributes of other extinct animals. In the future, this increased understanding of hemoglobin mutations could aid the development of human hemoglobin substitutes for therapeutic uses.

The availability of gonadotropin therapy from FDA-approved pharmacies for men with hypogonadism and infertility.

Background: Recent changes to the Biologics Price Competition and Innovation Act of 2009 have created barriers to accessing therapy for men utilizing gonadotropins for hypogonadism and infertility. Aim: In this study we sought to investigate ways to decrease disparities in the treatment of male hypogonadism by increasing access to gonadotropin therapy by identifying 503b outsourcing pharmacies which currently provide gonadotropin therapy. Methods: A review of 503b compounding pharmacies was performed using the online published registry available from the US Food and Drug Administration (FDA). Each pharmacy was contacted regarding their ability to provide gonadotropin therapy. Pharmacies were also queried regarding the impact of FDA-related legal changes and cost considerations. Outcomes: The study outcomes were the number and location of FDA-approved 503b compounding pharmacies supplying human chorionic gonadotrophin (hCG) and/or follicle-stimulating hormone (FSH) for the treatment of male hypogonadism and infertility. Results: The 81 503b-compounding pharmacies approved by the FDA to produce hCG and FSH therapy were identified using the FDA registry. Seventy-five of the 81 pharmacies responded to the survey (response rate 92.6%). Of the contacted pharmacies, 5 provided hCG (6.67%). Of the pharmacies offering compounded hCG, 4 offered FSH. No additional pharmacies offered compounded FSH. Eight pharmacies had previously provided hCG and FSH. Six of the 8 pharmacies that stopped making hCG and FSH cited the 2020 FDA mandate as the reason for halting compounding services. Of the 75 pharmacies that responded, only 1 pharmacy provided the cost for FSH ($287 per 100-IU vial), and 3 pharmacies provided the cost for hCG ($50-$83 per 10 000-IU vial). Clinical Implications: There are few FDA-approved outsourcing pharmacies currently providing male gonadotropin therapy, and increasing awareness of these pharmacies may decrease barriers to care for patients with male hypogonadism and infertility. Strengths and Limitations: The strengths of this article are the clinical utility of the data presented, as this article may serve as a tool for clinicians to increase patient access to therapy. All FDA-approved 503b outsourcing pharmacies were contacted, and 92.6% participated in this project. Limitations of this article were the following: no non-FDA-approved compounding pharmacies such as 503a pharmacies were contacted, participant-reported outcomes were utilized, and only 3 contacted outsourcing pharmacies provided a cost for FSH or hCG, allowing for an unknown degree of cost variability between outsourcing pharmacies. Conclusions: There currently exists limited access to FDA-approved compounded gonadotropin therapies for hypogonadism and male infertility, and these results demonstrate the barriers to hCG and FSH access and the need for additional treatment options for this vulnerable patient population.

A Multilingual Chatbot Can Effectively Engage Arthroplasty Patients Who Have Limited English Proficiency.

BACKGROUND: In the United States, English language proficiency is widely accepted as a key social determinant of health. For patients with limited English proficiency (LEP), language barriers can make the delivery of perioperative instructions challenging. The purpose of this study was to evaluate whether a multilingual chatbot could effectively engage LEP patients and improve their outcome after total joint arthroplasty (TJA). METHODS: We identified 1,282 TJA patients (705 knees, 577 hips) who enrolled in a short message service (SMS) chatbot from 2020-2022. Forty-seven patients enrolled in the chatbot received their messages in a language other than English. A historical control of 68 LEP patients not enrolled in the chatbot was identified. Chi-squared, Fisher's exact test, and t-tests were performed to measure the effect that conversational engagement had on emergency department (ED) visits, hospital readmissions, and reoperations. RESULTS: There was no difference in the conversational engagement between LEP patients and those with English as their primary language (EPL) (12.3 versus 12.2 text responses, P = .959). The LEP cohort who enrolled in the chatbot had fewer readmissions (0% versus 8.3%, P = .013) and a near significant reduction in ED visits (0.9% versus 8.0%, P = .085) compared to those not enrolled. There was no difference in reoperations between the 2 cohorts. CONCLUSION: LEP and EPL patients engaged equally with the multilingual chatbot. LEP patients who enrolled in the chatbot had fewer readmissions and a near significant reduction in ED visits. Multilingual platforms such as this chatbot may provide more equitable care to our frequently encountered LEP patients.

Impact of intensive follow-up of cardiac implantable electronic devices via remote monitoring: A pilot study.

Background: The volume of remote monitoring (RM) data generates a significant workload and is generally dealt with by clinic staff during standard office hours, potentially delaying clinical action. Objective: The purpose of this study was to determine the clinical efficiency and workflow of implementing intensive RM (IRM) in patients with cardiac implantable electronic device (CIED) when compared with standard RM (SRM). Methods: From a cohort of >1500 remotely monitored devices, 70 patients were randomly selected to undergo IRM. For comparison, an equal number of matched patients were prospectively selected for SRM. Intensive follow-up occurred via automated vendor-neutral software with rapid alert processing by International Board of Heart Rhythm Examiners-certified device specialists. Standard follow-up was conducted by clinic staff during office hours via individual device vendor interfaces. Alerts were categorized on the basis of the level of acuity as actionable (red [high], yellow [moderate]), or green [not requiring action]). Results: Over 9 months of follow-up, 922 remote transmissions were received; 339 (36.8%) were coded as actionable alerts (118 in IRM and 221 in SRM; P < .001). The median time from initial transmission to review was 6 hours (interquartile range [IQR] 1.8-16.8 hours) in the IRM group compared with 10.5 hours (IQR 6.0-32.2 hours) in the SRM group (P < .001). The median time from transmission to review of actionable alerts in the IRM group was 5.1 hours (IQR 2.3-8.9 hours) compared with 9.1 hours (IQR 6.7-32.5 hours) in the SRM group (P < .001). Conclusion: Intensive and managed RM results in a significant reduction in time to review alerts and number of actionable alerts. Monitoring with enhanced alert adjudication is needed to facilitate device clinic efficiency and optimize patient care. Study Registration: ACTRN12621001275853.

Device-detected atrial fibrillation in a large remote-monitored cohort: implications for anticoagulation and need for new pathways of service delivery.

BACKGROUND: Remote monitoring (RM) can facilitate early detection of subclinical and symptomatic atrial fibrillation (AF), providing an opportunity to evaluate the need for stroke prevention therapies. We aimed to characterize the burden of RM AF alerts and its impact on anticoagulation of patients with device-detected AF. METHODS: Consecutive patients with a cardiac implantable electronic device, at least one AF episode, undergoing RM were included and assigned an estimated minimum CHA2DS2-VASc score based on age and device type. RM was provided via automated software system, providing rapid alert processing by device specialists and systematic, recurrent prompts for anticoagulation. RESULTS: From 7651 individual, 389,188 AF episodes were identified, 3120 (40.8%) permanent pacemakers, 2260 (29.5%) implantable loop recorders (ILRs), 987 (12.9%) implantable cardioverter defibrillators, 968 (12.7%) cardiac resynchronization therapy (CRT) defibrillators, and 316 (4.1%) CRT pacemakers. ILRs transmitted 48.8% of all AF episodes. At twelve-months, 3404 (44.5%) AF < 6 min, 1367 (17.9%) 6 min-6 h, 1206 (15.8%) 6-24 h, and 1674 (21.9%) ≥ 24 h. A minimum CHA2DS2-VASc score of 2 was assigned to 1704 (63.1%) of the patients with an AF episode of ≥ 6 h, 531 (31.2%) who were not anticoagulated at 12-months, and 1031 (61.6%) patients with an AF episode duration of ≥ 24 h, 290 (28.1%) were not anticoagulated. CONCLUSIONS: Despite being intensively managed via RM software system incorporating cues for anticoagulation, a substantial proportion of patients with increased stroke risk remained unanticoagulated after a device-detected AF episode of significant duration. These data highlight the need for improved clinical response pathways and an integrated care approach to RM. TRIAL REGISTRATION: Australian New Zealand Clinical Trial Registry: ACTRN12620001232921.

N-terminal domain on dystroglycan enables LARGE1 to extend matriglycan on α-dystroglycan and prevents muscular dystrophy.

Dystroglycan (DG) requires extensive post-translational processing and O-glycosylation to function as a receptor for extracellular matrix (ECM) proteins containing laminin-G (LG) domains. Matriglycan is an elongated polysaccharide of alternating xylose (Xyl) and glucuronic acid (GlcA) that binds with high affinity to ECM proteins with LG domains and is uniquely synthesized on α-dystroglycan (α-DG) by like-acetylglucosaminyltransferase-1 (LARGE1). Defects in the post-translational processing or O-glycosylation of α-DG that result in a shorter form of matriglycan reduce the size of α-DG and decrease laminin binding, leading to various forms of muscular dystrophy. Previously, we demonstrated that protein O-mannose kinase (POMK) is required for LARGE1 to generate full-length matriglycan on α-DG (~150-250 kDa) (Walimbe et al., 2020). Here, we show that LARGE1 can only synthesize a short, non-elongated form of matriglycan in mouse skeletal muscle that lacks the DG N-terminus (α-DGN), resulting in an ~100-125 kDa α-DG. This smaller form of α-DG binds laminin and maintains specific force but does not prevent muscle pathophysiology, including reduced force production after eccentric contractions (ECs) or abnormalities in the neuromuscular junctions. Collectively, our study demonstrates that α-DGN, like POMK, is required for LARGE1 to extend matriglycan to its full mature length on α-DG and thus prevent muscle pathophysiology.