A systematic review of early phase studies for children and young people with relapsed and refractory rhabdomyosarcoma: The REFoRMS-SR project.

Rhabdomyosarcoma is the commonest soft tissue sarcoma in children. Around one-third of children with rhabdomyosarcoma experience relapse or have refractory disease, which is associated with a poor prognosis. This systematic review of early phase studies in pediatric relapsed/refractory rhabdomyosarcoma was conducted to inform future research and provide accurate information to families and clinicians making difficult treatment choices. Nine databases and five trial registries were searched in June 2021. Early phase studies of interventions for disease control in patients under 18 years old with relapsed/refractory rhabdomyosarcoma were eligible. No language/geographic restrictions were applied. Studies conducted after 2000 were included. Survival outcomes, response rates, quality of life and adverse event data were extracted. Screening, data extraction and quality assessment (Downs and Black Checklist) were conducted by two researchers. Owing to heterogeneity in the included studies, narrative synthesis was conducted. Of 16,965 records screened, 129 published studies including over 1100 relapsed/refractory rhabdomyosarcoma patients were eligible. Most studies evaluated systemic therapies. Where reported, 70% of studies reported a median progression-free survival ≤6 months. Objective response rate was 21.6%. Adverse events were mostly hematological. One-hundred and seven trial registry records of 99 studies were also eligible, 63 of which report they are currently recruiting. Study quality was limited by poor and inconsistent reporting. Outcomes for children with relapsed/refractory rhabdomyosarcoma who enroll on early phase studies are poor. Improving reporting quality and consistency would facilitate the synthesis of early phase studies in relapsed/refractory rhabdomyosarcoma (PROSPERO registration: CRD42021266254).

Effects of resistance exercise, collagen ingestion and circulating oestrogen concentration on collagen synthesis in a female athlete: A case report.

We investigated the effects of resistance exercise (RE), hydrolysed collagen (HC) ingestion and circulating oestrogen concentration on collagen synthesis in a naturally menstruating female CrossFit athlete. In a double-blind, randomised cross-over design, the participant (36 years; height 1.61 m; mass 82.6 kg) consumed 0 or 30 g HC prior to performing back-squat RE when endogenous circulating oestrogen concentration was low (onset of menses, OM) and high (late follicular phase, LF) during two consecutive menstrual cycles. Ten 5-mL blood samples were collected during each of the four interventions to analyse concentrations of serum 17ß-oestradiol, and biomarkers of type I collagen turnover, that is serum procollagen type I N-terminal propeptide (PINP, a biomarker of collagen synthesis) and plasma ß-isomerised C-terminal telopeptide of type I collagen (ß-CTX, a biomarker of collagen breakdown), as well as the serum concentration of 18 collagen amino acids. 17ß-Oestradiol concentration was 5-fold higher at LF (891 ± 116 pmol L-1) than OM (180 ± 13 pmol L-1). The PINP concentration × time area under the curve (AUC) was higher in the 30 g HC OM intervention (201 µg L-1 h) than the 30 g HC LF (144 µg L-1 h), 0 g HC OM (151 µg L-1 h) and 0 g HC LF (122 µg L-1 h) interventions. ß-CTX concentration decreased 1.4-fold from pre-RE to 6 h post-RE in all interventions. Thus, high circulating oestrogen concentration was associated with lower collagen synthesis following RE in this female athlete. Ingesting 30 g HC, however, augmented the collagen synthesis response at LF and particularly at OM. HIGHLIGHTS: What is the central question of this study? Does resistance exercise-induced collagen synthesis vary according to circulating oestrogen concentration in a naturally menstruating female athlete, and if so, does hydrolysed collagen ingestion have any impact? What is the main finding and its importance? Exercise-induced collagen synthesis was low when circulating oestrogen concentration was high and vice versa. However, ingesting 30 g hydrolysed collagen prior to exercise reduced the negative effect of oestrogen on collagen synthesis. As high circulating oestrogen has been associated with greater injury risk in females, supplementing exercise with hydrolysed collagen may help protect these tissues from injury.

Ageing Skeletal Muscle: The Ubiquitous Muscle Stem Cell.

In 1999, in a review by Beardsley, the potential of adult stem cells, in repair and regeneration was heralded (Beardsley Sci Am 281:30-31, 1999). Since then, the field of regenerative medicine has grown exponentially, with the capability of restoring or regenerating the function of damaged, diseased or aged human tissues being an underpinning motivation. If successful, stem cell therapies offer the potential to treat, for example degenerative diseases. In the subsequent 20 years, extensive progress has been made in the arena of adult stem cells (for a recent review see (Zakrzewski et al. Stem Cell Res Ther 10:68, 2019)). Prior to the growth of the adult stem cell research arena, much focus had been placed on the potential of embryonic stem cells (ESCs). The first research revealing the potential of these cells was published in 1981, when scientists reported the ability of cultured stem cells from murine embryos, to not only self-renew, but to also become all cells of the three germ layers of the developing embryo (Evans and Kaufman Nature 292:154-156, 1981), (Martin Proc Natl Acad Sci U S A 78:7634-7638, 1981). It took almost 20 years, following these discoveries, for this technology to translate to human ESCs, using donated human embryos. In 1998, Thomson et al. reported the creation of the first human embryonic cell line (Thomson et al. Science 282:1145-1147, 1998). However, research utilising human ESCs was hampered by ethical and religious constraints and indeed in 2001 George W. Bush restricted US research funding to human ESCs, which had already been banked. The contentious nature of this arena perhaps facilitated the use of and the research potential for adult stem cells. It is beyond the scope of this review to focus on ESCs, although their potential for enhancing our understanding of human development is huge (for a recent review see (Cyranoski Nature 555:428-430, 2018)). Rather, although ESCs and their epigenetic regulation will be introduced for background understanding, the focus will be on stem cells more generally, the role of epigenetics in stem cell fate, skeletal muscle, skeletal muscle stem cells, the impact of ageing on muscle wasting and the mechanisms underpinning loss, with a focus on epigenetic adaptation.

Twelve tips to aid interpretation of post-assessment psychometric reports.

Post-assessments psychometric reports are a vital component of the assessment cycle to ensure that assessments are reliable, valid and fair to make appropriate pass-fail decisions. Students' scores can be summarised by examination of frequency distributions, central tendency measures and dispersion measures. Item discrimination indicies to assess the quality of items, and distractors that differentiate between students achieving or not achieving the learning outcomes are key. Estimating individual item reliability and item validity indices can maximise test-score reliability and validity. Test accuracy can be evaluated by assessing test reliability, consistency and validity and standard error of measurement can be used to measure the variation. Standard setting, even by experts, may be unreliable and reality checks such as the Hofstee method, P values and correlation analysis can improve validity. The Rasch model of student ability and item difficulty assists in modifying assessment questions, pinpointing areas for additional instruction. We propose 12 tips to support test developers in interpreting structured psychometric reports, including analysis and refinement of flawed items and ensuring fair assessments with accurate and defensible marks.

Barriers to Mental Health care in Canada Identified by Healthcare Providers: A Scoping Review.

The mental health treatment gap remains wide across the world despite mental illness being a significant cause of disability globally. Both end-user and healthcare provider perspectives are critical to understanding barriers to mental healthcare and developing interventions. However, the views of providers are relatively understudied. In this review, we synthesized findings from current literature regarding providers' perspectives on barriers to mental healthcare in Canada. We searched Medline, PsycINFO, Embase, and CINAHL for eligible Canadian studies published since 2000. Analysis and quality assessment were conducted on the included studies. Of 4,773 reports screened, 29 moderate-high quality studies were reviewed. Five themes of barriers emerged: health systems availability and complexity (reported in 72% of the studies), work conditions (55%), training/education (52%), patient accessibility (41%), and identity-based sensitivity (17%). Common barriers included lack of resources, fragmented services, and gaps in continuing education. Interestingly, clinicians often cited confusion in determining the ideal service for patients due to an overwhelming number of potential services without clear descriptions. These five domains of barriers present a synthesized review of areas of improvement for mental healthcare spanning both patients and clinicians. Canadian mental health systems face a need to improve capacity, clinician training, and in particular service navigability and collaboration.

PCM1 labeling reveals myonuclear and nuclear dynamics in skeletal muscle across species.

Myonuclei transcriptionally regulate muscle fibers during homeostasis and adaptation to exercise. Their subcellular location and quantity are important when characterizing phenotypes of myopathies, the effect of treatments, and understanding the roles of satellite cells in muscle adaptation and muscle "memory." Difficulties arise in identifying myonuclei due to their proximity to the sarcolemma and closely residing interstitial cell neighbors. We aimed to determine to what extent (pericentriolar material-1) PCM1 is a specific marker of myonuclei in vitro and in vivo. Single isolated myofibers and cross sections from mice and humans were studied from several models including wild-type and Lamin A/C mutant mice after functional overload and damage and recovery in humans following forced eccentric contractions. Fibers were immunolabeled for PCM1, Pax7, and DNA. C2C12 myoblasts were also studied to investigate changes in PCM1 localization during myogenesis. PCM1 was detected at not only the nuclear envelope of myonuclei in mature myofibers and in newly formed myotubes but also centrosomes in proliferating myogenic precursors, which may or may not fuse to join the myofiber syncytium. PCM1 was also detected in nonmyogenic nuclei near the sarcolemma, especially in regenerating areas of the Lmna+/ΔK32 mouse and damaged human muscle. Although PCM1 is not completely specific to myonuclei, the impact that PCM1+ macrophages and interstitial cells have on myonuclei counts would be small in healthy muscle. PCM1 may prove useful as a marker of satellite cell dynamics due to the distinct change in localization during differentiation, revealing satellite cells in their quiescent (PCM1-), proliferating (PCM1+ centrosome), and prefusion states (PCM1+ nuclear envelope).

The Collagen Synthesis Response to an Acute Bout of Resistance Exercise Is Greater when Ingesting 30 g Hydrolyzed Collagen Compared with 15 g and 0 g in Resistance-Trained Young Men.

BACKGROUND: Resistance exercise (RE) stimulates collagen synthesis in skeletal muscle and tendon but there is limited and equivocal evidence regarding an effect of collagen supplementation and exercise on collagen synthesis. Furthermore, it is not known if a dose-response exists regarding the effect of hydrolyzed collagen (HC) ingestion and RE on collagen synthesis. OBJECTIVE: To determine the HC dose-response effect on collagen synthesis after high-intensity RE in resistance-trained young men. METHODS: Using a double-blind, randomized crossover design, 10 resistance-trained males (age: 26 ± 3 y; height: 1.77 ± 0.04 m; mass: 79.7 ± 7.0 kg) ingested 0 g, 15 g, or 30 g HC with 50 mg vitamin C 1 h before performing 4 sets' barbell back squat RE at 10-repetition maximum load, after which they rested for 6 h. Blood samples were collected throughout each of the 3 interventions to analyze procollagen type Ⅰ N-terminal propeptide (PINP) and ß-isomerized C-terminal telopeptide of type I collagen (ß-CTX) concentration, and the concentration of 18 collagen amino acids. RESULTS: The serum PINP concentration × time area under the curve (AUC) was greater for 30 g (267 ± 79 µg·L-1·h) than for 15 g (235 ± 70 µg·L-1·h, P = 0.013) and 0 g HC (219 ± 88 µg·L-1·h, P = 0.002) but there was no difference between 0 and 15 g HC (P = 0.225). The AUCs of glycine and proline were greater for 30 g than for 15 and 0 g HC (P < 0.05). Plasma ß-CTX concentration decreased from -1 to +6 h (P < 0.05), with no differences between interventions. CONCLUSIONS: Ingesting 30 g HC before high-intensity RE augments whole-body collagen synthesis more than 15 g and 0 g HC in resistance-trained young males.

Serum concentration impacts myosin heavy chain expression but not cellular respiration in human LHCN-M2 myoblasts undergoing differentiation.

NEW FINDINGS: What is the central question of this study? Does the concentration of human serum affect skeletal muscle differentiation and cellular respiration of LHCN-M2 myoblasts? What is the main finding and its importance? The concentration of serum used to differentiate LHCN-M2 skeletal muscle cells impacts the coverage of myosin heavy chain, a marker of terminally differentiated myotubes. Normalisation of mitochondrial function data to total protein negates the differences observed in absolute values, which differ as a result of increased protein content when differentiation occurs with increasing concentration of serum. ABSTRACT: The human LHCN-M2 myoblast cell line has the potential to be used to investigate skeletal muscle development and metabolism. Experiments were performed to determine how different concentrations of human serum affect myogenic differentiation and mitochondrial function of LHCN-M2 cells. LHCN-M2 myoblasts were differentiated in serum-free medium, 0.5% or 2% human serum for 5 and 10 days. Myotube formation was assessed by immunofluorescence staining of myosin heavy chain (MHC) and molecularly by mRNA expression of Myogenic differentiation 1 (MYOD1) and Myoregulatory factor 5 (MYF5). Following differentiation, mitochondrial function was assessed to establish the impact of serum concentration on mitochondrial function. Time in differentiation increased mRNA expression of MYOD1 (day 5, 6.58 ± 1.33-fold; and day 10, 4.28 ± 1.71-fold) (P = 0.012), while suppressing the expression of MYF5 (day 5, 0.21 ± 0.11-fold; and day 10, 0.06 ± 0.03-fold) (P = 0.001), regardless of the serum concentration. Higher serum concentrations increased MHC area (serum free, 11.92 ± 0.85%; 0.5%, 23.10 ± 5.82%; 2%, 43.94 ± 8.92%) (P = 0.001). Absolute basal respiration approached significance (P = 0.06) with significant differences in baseline oxygen consumption rate (P = 0.025) and proton leak (P = 0.006) when differentiated in 2% human serum, but these were not different between conditions when normalised to total protein. Our findings show that increasing concentrations of serum of LHCN-M2 skeletal muscle cells into multinucleated myotubes, but this does not affect relative mitochondrial function.

"I Want Them to Still Trust Me with Their Child's Care": A Longitudinal Study of Pediatric Residents' Reactions to and Communication with Parents about Medical Uncertainty across Residency.

Physicians in residency training experience high levels of medical uncertainty, yet they are often hesitant to discuss uncertainty with parents. Guided by the theory of motivated information management and a multiple goals perspective, this mixed-methods longitudinal study examines associations among residents' tolerance of and reactions to uncertainty, efficacy communicating about uncertainty, and perceptions of parents' trust in them as physicians. To contextualize these associations, we also examined residents' task, identity, and relational goals when communicating about uncertainty with parents. We surveyed 47 pediatric residents at the beginning of each year of their residency program. As they progressed through their training, residents' uncertainty-related anxiety and reluctance to communicate uncertainty to parents decreased, and their efficacy communicating uncertainty with parents increased. Residents' concerns about bad outcomes remained unchanged. Residents pursued multiple, often conflicting, conversational goals when communicating uncertainty with parents. Results reveal important considerations for addressing how residents can manage their uncertainty in productive ways.

Faculty Decision Making in Ad Hoc Entrustment of Pediatric Critical Care Fellows: A National Case-Based Survey.

Phenomenon: Ad hoc entrustment decisions reflect a clinical supervisor's estimation of the amount of supervision a trainee needs to successfully complete a task in the moment. These decisions have important consequences for patient safety, trainee learning, and preparation for independent practice. Determinants of these decisions have previously been described but have not been well described for acute care contexts such as critical care and emergency medicine. The ad hoc entrustment of trainees caring for vulnerable patient populations is a high-stakes decision that may differ from other contexts. Critically ill patients and children are vulnerable patient populations, making the ad hoc entrustment of a pediatric critical care medicine (PCCM) fellow a particularly high-stakes decision. This study sought to characterize how ad hoc entrustment decisions are made for PCCM fellows through faculty ratings of vignettes. The authors investigated how acuity, relationship, training level, and task interact to influence ad hoc entrustment decisions. Approach: A survey containing 16 vignettes that varied by four traits (acuity, relationship, training level, and task) was distributed to U.S. faculty of pediatric critical care fellowships in 2020. Respondents determined an entrustment level for each case and provided demographic data. Entrustment ratings were dichotomized by "high entrustment" versus "low entrustment" (direct supervision or observation only). The authors used logistic regression to evaluate the individual and interactive effects of the four traits on dichotomized entrustment ratings. Findings: One hundred seventy-eight respondents from 30 institutions completed the survey (44% institutional response rate). Acuity, relationship, and task all significantly influenced the entrustment level selected but did not interact. Faculty most frequently selected "direct supervision" as the entrustment level for vignettes, including for 24% of vignettes describing fellows in their final year of training. Faculty rated the majority of vignettes (61%) as "low entrustment." There was no relationship between faculty or institutional demographics and the entrustment level selected. Insights: As has been found in summative entrustment for pediatrics, internal medicine, and surgery trainees, PCCM fellows often rated at or below the "direct supervision" level of ad hoc entrustment. This may relate to declining opportunities to practice procedures, a culture of low trust propensity among the specialty, and/or variation in interpretation of entrustment scales.

A Difference between In Vitro and In-Cell Protein Dimer Formation.

The high concentration of macromolecules in cells affects the stability of proteins and protein complexes via hard repulsions and chemical interactions, yet few studies have focused on chemical interactions. We characterized the domain-swapped dimer of the B1 domain of protein G in buffer and Escherichia coli cells by using heteronuclear, multidimensional nuclear magnetic resonance spectroscopy. In buffer, the monomer is a partially folded molten globule, but that species is not observed in cells. Experiments using urea suggest that the monomer is unfolded in cells, but again, the molten-globule form of the monomer is absent. The data suggest that attractive chemical interactions in the cytoplasm unfold the molten globule. We conclude that the intracellular environment not only modulates the stability of protein complexes but also can change the species present, reinforcing the idea that chemical interactions are more important than hard repulsions in cells.

Polygenic mechanisms underpinning the response to exercise-induced muscle damage in humans: In vivo and in vitro evidence.

We investigated whether 20 candidate single nucleotide polymorphisms (SNPs) were associated with in vivo exercise-induced muscle damage (EIMD), and with an in vitro skeletal muscle stem cell wound healing assay. Sixty-five young, untrained Caucasian adults performed 120 maximal eccentric knee-extensions on an isokinetic dynamometer to induce EIMD. Maximal voluntary isometric/isokinetic knee-extensor torque, knee joint range of motion (ROM), muscle soreness, serum creatine kinase activity and interleukin-6 concentration were assessed before, directly after and 48 h after EIMD. Muscle stem cells were cultured from vastus lateralis biopsies from a separate cohort (n = 12), and markers of repair were measured in vitro. Participants were genotyped for all 20 SNPs using real-time PCR. Seven SNPs were associated with the response to EIMD, and these were used to calculate a total genotype score, which enabled participants to be segregated into three polygenic groups: 'preferential' (more 'protective' alleles), 'moderate', and 'non-preferential'. The non-preferential group was consistently weaker than the preferential group (1.93 ± 0.81 vs. 2.73 ± 0.59 N ∙ m/kg; P = 9.51 × 10-4 ) and demonstrated more muscle soreness (p = 0.011) and a larger decrease in knee joint ROM (p = 0.006) following EIMD. Two TTN-AS1 SNPs in linkage disequilibrium were associated with in vivo EIMD (rs3731749, p ≤ 0.005) and accelerated muscle stem cell migration into the artificial wound in vitro (rs1001238, p ≤ 0.006). Thus, we have identified a polygenic profile, linked with both muscle weakness and poorer recovery following EIMD. Moreover, we provide evidence for a novel TTN gene-cell-skeletal muscle mechanism that may help explain some of the interindividual variability in the response to EIMD.

Pharmacological interventions for alcohol misuse in correctional settings: A systematic review.

BACKGROUND: The prevalence of alcohol use disorder (AUD) is estimated to be 10 times higher amongst individuals in the criminal justice system than the general population. Alcohol use is also one of the strongest modifiable risk factors for recidivism. One intervention that has been shown to be effective in reducing alcohol consumption in the general population is medication-assisted treatment (MAT), and this systematic review synthesized the existing evidence on MAT for AUD in correctional settings. METHODS: Empirical, peer-reviewed studies on approved medications for AUD in correctional populations were searched in major databases. One hundred sixty-two articles were initially screened and 14 eligible articles were included in the final review. Four articles examined disulfiram, and 10 articles examined naltrexone. RESULTS: The studies on disulfiram were considerably older than those on naltrexone, predating contemporary scientific standards. Disulfiram in combination with substantial contingencies in a supervised setting significantly reduced alcohol-related measures of consumption and recidivism and had acceptable safety and tolerability. All naltrexone studies showed significant reductions in alcohol-related measures, but effects on recidivism were mixed. The naltrexone studies indicated that it was highly acceptable and well tolerated. In addition, offenders receiving naltrexone had significantly greater medication adherence, treatment attendance, and treatment duration than with placebo. CONCLUSIONS: A small number of studies on pharmacological interventions for AUD in the correctional population suggest that MAT is effective in reducing alcohol consumption, although results on recidivism are mixed. On balance, the evidence was more supportive of naltrexone in reducing alcohol-related outcomes than disulfiram and it may also be a more feasible intervention in correctional settings. Further research on MAT to address AUD in correctional populations with larger sample sizes, longer duration, and in combination with behavioral interventions is warranted.

Developing tailored theoretically informed goal-setting interventions for rehabilitation services: a co-design approach.

BACKGROUND: Several active ingredients contribute to the purposes and mechanisms of goal-setting in rehabilitation. Active ingredients in the goal-setting process include, interdisciplinary teamworking, shared decision-making, having meaningful and specific goals, and including action planning, coping planning, feedback, and review. Clinicians have expressed barriers and enablers to implementing these active ingredients in rehabilitation teams. Interventions designed to improve goal-setting practices need to be tailored to address context specific barriers and enablers. Attempts to understand and enhance goal-setting practices in rehabilitation settings should be supported using theory, process models and determinant frameworks. Few studies have been undertaken to enhance goal-setting practices in varied case-mix rehabilitation settings. METHODS: This study is part of a larger program of research guided by the Knowledge to Action (KTA) framework. A multisite, participatory, codesign approach was used in five sites to address three stages of the KTA. (1) Focus groups were conducted to understand barriers and enablers to implementing goal-setting at each site. Following the focus groups three staff co-design workshops and one consumer workshop were run at each site to (2) adapt knowledge to local context, and to (3) select and tailor interventions to improve goal-setting practices. Focus groups were analysed using the Theoretical Domains Framework (TDF) and informed the selection of behaviour change techniques incorporated into the implementation plan. RESULTS: Barriers and enablers identified in this study were consistent with previous research. Clinicians lacked knowledge and understanding of the differences between a goal and an action plan often confusing both terms. Clinicians were unable to demonstrate an understanding of the importance of comprehensive action planning and review processes that extended beyond initial goal-setting. Interventions developed across the sites included staff training modules, a client held workbook, educational rehabilitation service flyers, interdisciplinary goal-based case conference templates, communication goal boards and a key worker model. Implementation plans were specifically established for each site. CONCLUSIONS: Rehabilitation teams continue to struggle to incorporate a truly client-centred, interdisciplinary model of goal-setting in rehabilitation. Whilst clinicians continue to lack understanding of how they can use aspects of goal-setting to enhance client outcomes and autonomy in rehabilitation settings.

Physical activity assessment and vascular function in adults with cystic fibrosis and their non-CF peers.

An understanding of physical activity (PA) and related health benefits remains limited in adults with Cystic Fibrosis (CF). Raw acceleration data metrics may improve the quality of assessment and further this understanding. The study aimed to compare PA between people with CF (pwCF) and non-CF peers and examine associations between PA, vascular function and health outcome measures. PA was assessed in 62 participants (31 pwCF) using ActiGraph accelerometers. Vascular function (a marker of cardiovascular disease risk) was assessed using flow-mediated dilatation (FMD) in sub-groups of pwCF (n = 12) and matched controls. Average Euclidean norm minus one (ENMO) (total PA) was significantly lower (p = 0.005) in pwCF (35.09 ± 10.60 mg), than their non-CF peers (44.62 ± 13.78 mg). PwCF had PA profiles (intensity gradient) indicative of more time in lower intensity activity (-2.62 ± 0.20, -2.37 ± 0.23). Vigorous activity was positively associated with lung function (rs = 0.359) and Quality of Life (r = 0.412). There were no significant differences (p = 0.313) in FMD% between pwCF (5.29 ± 2.76%) and non-CF peers (4.34 ± 1.58%) and no associations with PA. PwCF engaged in less moderate-to-vigorous PA and demonstrated a steeper PA profile than their non-CF peers.

Improving CPR Quality by Using a Real-Time Feedback Defibrillator During Pediatric Simulation Training.

OBJECTIVE: The aim of this study was to assess the effectiveness of a defibrillator with real-time feedback during code team training to improve adherence to the American Heart Association (AHA) resuscitation guidelines. METHODS: This is a retrospective cohort study designed to compare pediatric resident adherence to the AHA cardiopulmonary resuscitation guidelines before and after use of real-time feedback defibrillator during code team training simulation. After institution of a real-time feedback defibrillator, first-year resident's adherence to the AHA guidelines for chest compression rate (CCR), fraction, and depth during code team training from January 2017 to December 2018 was analyzed. It was then compared with results of a previously published study from our institution that analyzed the CCR and fraction from January 2015 to January 2016, before the implementation of a defibrillator with real-time feedback. RESULTS: We compared 19 eligible session preintervention and 36 postintervention sessions. Chest compression rate and chest compression fraction (CCF) were assessed preintervention and postintervention. The depth of compression was only available postintervention. There was improvement in the proportion of code team training sessions with mean compression rate (74% preintervention vs 100% postintervention, P = 0.003) and mean CCF (79% vs 97%, P = 0.04) in adherence with the AHA guideline. CONCLUSIONS: The use of real-time feedback defibrillators improved the adherence to the AHA cardiopulmonary resuscitation guidelines for CCF and CCR during pediatric resident simulation.

Severe SARS-CoV-2 disease in the context of a NF-κB2 loss-of-function pathogenic variant.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus that emerged recently and has created a global pandemic. Symptomatic SARS-CoV-2 infection, termed coronavirus disease 2019 (COVID-19), has been associated with a host of symptoms affecting numerous organ systems, including the lungs, cardiovascular system, kidney, central nervous system, gastrointestinal tract, and skin, among others. OBJECTIVE: Although several risk factors have been identified as related to complications from and severity of COVID-19, much about the virus remains unknown. The host immune response appears to affect the outcome of disease. It is not surprising that patients with intrinsic or secondary immune compromise might be particularly susceptible to complications from SARS-CoV-2 infection. Pathogenic loss-of-function or gain-of-function heterozygous variants in nuclear factor-κB2 have been reported to be associated with either a combined immunodeficiency or common variable immunodeficiency phenotype. METHODS: We evaluated the functional consequence and immunologic phenotype of a novel NFKB2 loss of function variant in a 17-year-old male patient and describe the clinical management of SARS-CoV-2 infection in this context. RESULTS: This patient required a 2-week hospitalization for SARS-CoV-2 infection, including 7 days of mechanical ventilation. We used biologic therapies to avert potentially fatal acute respiratory distress syndrome and treat hyperinflammatory responses. The patient had an immunologic phenotype of B-cell dysregulation with decreased switched memory B cells. Despite the underlying immune dysfunction, he recovered from the infection with intense management. CONCLUSIONS: This clinical case exemplifies some of the practical challenges in management of patients with SARS-CoV-2 infection, especially in the context of underlying immune dysregulation.

Dynamic Profiling of Protein Mole Synthesis Rates during C2C12 Myoblast Differentiation.

Mole (MSR) and fractional (FSR) synthesis rates of proteins during C2C12 myoblast differentiation are investigated. Myoblast cultures supplemented with D2 O during 0-24 h or 72-96 h of differentiation are analyzed by LC-MS/MS to calculate protein FSR and MSR after samples are spiked with yeast alcohol dehydrogenase (ADH1). Profiling of 153 proteins detected 70 significant (p ≤ 0.05, FDR ≤ 1%) differences in abundance between cell states. Early differentiation is enriched by clusters of ribosomal and heat shock proteins, whereas later differentiation is associated with actin filament binding. The median (first-third quartile) FSR (%/h) during early differentiation 4.1 (2.7-5.3) is approximately twofold greater than later differentiation 1.7 (1.0-2.2), equating to MSR of 0.64 (0.38-1.2) and 0.28 (0.1-0.5) fmol h-1  µg-1 total protein, respectively. MSR corresponds more closely with abundance data and highlights proteins associated with glycolytic processes and intermediate filament protein binding that are not evident among FSR data. Similarly, MSR during early differentiation accounts for 78% of the variation in protein abundance during later differentiation, whereas FSR accounts for 4%. Conclusively, the interpretation of protein synthesis data differs when reported in mole or fractional terms, which has consequences when studying the allocation of cellular resources.

Knockdown of the E3 ubiquitin ligase UBR5 and its role in skeletal muscle anabolism.

UBR5 is an E3 ubiquitin ligase positively associated with anabolism, hypertrophy, and recovery from atrophy in skeletal muscle. The precise mechanisms underpinning UBR5's role in the regulation of skeletal muscle mass remain unknown. The present study aimed to elucidate these mechanisms by silencing the UBR5 gene in vivo. To achieve this aim, we electroporated a UBR5-RNAi plasmid into mouse tibialis anterior muscle to investigate the impact of reduced UBR5 on anabolic signaling MEK/ERK/p90RSK and Akt/GSK3ß/p70S6K/4E-BP1/rpS6 pathways. Seven days after UBR5 RNAi electroporation, although reductions in overall muscle mass were not detected, the mean cross-sectional area (CSA) of green fluorescent protein (GFP)-positive fibers were reduced (-9.5%) and the number of large fibers were lower versus the control. Importantly, UBR5-RNAi significantly reduced total RNA, muscle protein synthesis, ERK1/2, Akt, and GSK3ß activity. Although p90RSK phosphorylation significantly increased, total p90RSK protein levels demonstrated a 45% reduction with UBR5-RNAi. Finally, these early events after 7 days of UBR5 knockdown culminated in significant reductions in muscle mass (-4.6%) and larger reductions in fiber CSA (-18.5%) after 30 days. This was associated with increased levels of phosphatase PP2Ac and inappropriate chronic elevation of p70S6K and rpS6 between 7 and 30 days, as well as corresponding reductions in eIF4e. This study demonstrates that UBR5 plays an important role in anabolism/hypertrophy, whereby knockdown of UBR5 culminates in skeletal muscle atrophy.

Mechanical loading of bioengineered skeletal muscle in vitro recapitulates gene expression signatures of resistance exercise in vivo.

Understanding the role of mechanical loading and exercise in skeletal muscle (SkM) is paramount for delineating the molecular mechanisms that govern changes in muscle mass. However, it is unknown whether loading of bioengineered SkM in vitro adequately recapitulates the molecular responses observed after resistance exercise (RE) in vivo. To address this, the transcriptional and epigenetic (DNA methylation) responses were compared after mechanical loading in bioengineered SkM in vitro and after RE in vivo. Specifically, genes known to be upregulated/hypomethylated after RE in humans were analyzed. Ninety-three percent of these genes demonstrated similar changes in gene expression post-loading in the bioengineered muscle when compared to acute RE in humans. Furthermore, similar differences in gene expression were observed between loaded bioengineered SkM and after programmed RT in rat SkM tissue. Hypomethylation occurred for only one of the genes analysed (GRIK2) post-loading in bioengineered SkM. To further validate these findings, DNA methylation and mRNA expression of known hypomethylated and upregulated genes post-acute RE in humans were also analyzed at 0.5, 3, and 24 h post-loading in bioengineered muscle. The largest changes in gene expression occurred at 3 h, whereby 82% and 91% of genes responded similarly when compared to human and rodent SkM respectively. DNA methylation of only a small proportion of genes analyzed (TRAF1, MSN, and CTTN) significantly increased post-loading in bioengineered SkM alone. Overall, mechanical loading of bioengineered SkM in vitro recapitulates the gene expression profile of human and rodent SkM after RE in vivo. Although some genes demonstrated differential DNA methylation post-loading in bioengineered SkM, such changes across the majority of genes analyzed did not closely mimic the epigenetic response to acute-RE in humans.