Detyrosinated microtubule arrays drive myofibrillar malformations in mdx muscle fibers.

Altered myofibrillar structure is a consequence of dystrophic pathology that impairs skeletal muscle contractile function and increases susceptibility to contraction injury. In murine Duchenne muscular dystrophy (mdx), myofibrillar alterations are abundant in advanced pathology (>4 months), an age where we formerly established densified microtubule (MT) arrays enriched in detyrosinated (deTyr) tubulin as negative disease modifiers impacting cell mechanics and mechanotransduction. Given the essential role of deTyr-enriched MT arrays in myofibrillar growth, maintenance, and repair, we examined the increased abundance of these arrays as a potential mechanism for these myofibrillar alterations. Here we find an increase in deTyr-tubulin as an early event in dystrophic pathology (4 weeks) with no evidence myofibrillar alterations. At 16 weeks, we show deTyr-enriched MT arrays significantly densified and co-localized to areas of myofibrillar malformation. Profiling the enzyme complexes responsible for deTyr-tubulin, we identify vasohibin 2 (VASH2) and small vasohibin binding protein (SVBP) significantly elevated in the mdx muscle at 4 weeks. Using the genetic increase in VASH2/SVBP expression in 4 weeks wild-type mice we find densified deTyr-enriched MT arrays that co-segregate with myofibrillar malformations similar to those in the 16 weeks mdx. Given that no changes in sarcomere organization were identified in fibers expressing sfGFP as a control, we conclude that disease-dependent densification of deTyr-enriched MT arrays underscores the altered myofibrillar structure in dystrophic skeletal muscle fibers.

Predicting response to immune checkpoint blockade in NSCLC with tumour-only RNA-seq.

BACKGROUND: Targeted RNA sequencing (RNA-seq) from FFPE specimens is used clinically in cancer for its ability to estimate gene expression and to detect fusions. Using a cohort of NSCLC patients, we sought to determine whether targeted RNA-seq could be used to measure tumour mutational burden (TMB) and the expression of immune-cell-restricted genes from FFPE specimens and whether these could predict response to immune checkpoint blockade. METHODS: Using The Cancer Genome Atlas LUAD dataset, we developed a method for determining TMB from tumour-only RNA-seq and showed a correlation with DNA sequencing derived TMB calculated from tumour/normal sample pairs (Spearman correlation = 0.79, 95% CI [0.73, 0.83]. We applied this method to targeted sequencing data from our patient cohort and validated these results against TMB estimates obtained using an orthogonal assay (Spearman correlation = 0.49, 95% CI [0.24, 0.68]). RESULTS: We observed that the RNA measure of TMB was significantly higher in responders to immune blockade treatment (P = 0.028) and that it was predictive of response (AUC = 0.640 with 95% CI [0.493, 0.786]). By contrast, the expression of immune-cell-restricted genes was uncorrelated with patient outcome. CONCLUSION: TMB calculated from targeted RNA sequencing has a similar diagnostic ability to TMB generated from targeted DNA sequencing.

A comprehensive review of computational and image analysis techniques for quantitative evaluation of striated muscle tissue architecture.

Unbiased evaluation of morphology is crucial to understanding development, mechanics, and pathology of striated muscle tissues. Indeed, the ability of striated muscles to contract and the strength of their contraction is dependent on their tissue-, cellular-, and cytoskeletal-level organization. Accordingly, the study of striated muscles often requires imaging and assessing aspects of their architecture at multiple different spatial scales. While an expert may be able to qualitatively appraise tissues, it is imperative to have robust, repeatable tools to quantify striated myocyte morphology and behavior that can be used to compare across different labs and experiments. There has been a recent effort to define the criteria used by experts to evaluate striated myocyte architecture. In this review, we will describe metrics that have been developed to summarize distinct aspects of striated muscle architecture in multiple different tissues, imaged with various modalities. Additionally, we will provide an overview of metrics and image processing software that needs to be developed. Importantly to any lab working on striated muscle platforms, characterization of striated myocyte morphology using the image processing pipelines discussed in this review can be used to quantitatively evaluate striated muscle tissues and contribute to a robust understanding of the development and mechanics of striated muscles.

A phase II study of tarloxotinib (a hypoxia activated prodrug of a pan-erb tyrosine kinase inhibitor) in patients with recurrent or metastatic squamous cell carcinoma of the head and neck or skin.

BACKGROUND: Tarloxotinib, a hypoxia-activated prodrug of an irreversible pan-ErbB tyrosine kinase inhibitor, represents a novel therapeutic which exploits the tumor-specific hypoxic environment as a mechanism for tumor-specific targeting. This study evaluated the safety and activity of tarloxotinib in recurrent or metastatic (R/M) cutaneous (CSCC) or head and neck squamous cell carcinoma (HNSCC). METHODS: This was a phase II two-stage multi-centre study for patients with R/M HNSCC or CSCC. All patients received tarloxotinib 150 mg/m2 on days 1,8,15 and 22 in a 28-day cycle. Stage 1 enrolled patients in three cohorts: p16-negative HNSCC, p16-positive oropharyngeal SCC, and CSCC. In order for a cohort to proceed to stage 2 a minimum response rate of 5% was required. RESULTS: 30 patients were enrolled: 23% were female with median age of 63.3 years. The median duration of follow-up was 20 weeks. The median progression-free survival was 2.0 months (95%CI 1.8-3.4) and median overall survival 5.7 months (95%CI 3.6-8.0). Treatment was well tolerated. The objective response rate was 3% with one patient with CSCC having a partial response. CONCLUSIONS: Hypoxia-activated prodrugs represent a novel approach to cancer treatment, however, no clinically meaningful benefit for tarloxotinib in R/M HNSCC or CSCC was identified in this study. TRIAL REGISTRATION NUMBER: NCT02449681 (May 20, 2015).

Targeted therapy for advanced anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer.

BACKGROUND: Targeted therapies directed at specific driver oncogenes have improved outcomes for individuals with advanced non-small cell lung cancer (NSCLC). Approximately 5% of lung adenocarcinomas, the most common histologic subtype of NSCLC, harbour rearrangements in the anaplastic lymphoma kinase (ALK) gene leading to constitutive activity of the ALK kinase. Crizotinib was the first tyrosine kinase inhibitor (TKI) demonstrated to be effective in advanced NSCLC. Next-generation ALK TKIs have since been developed including ceritinib, alectinib, brigatinib, ensartinib, and lorlatinib, and have been compared with crizotinib or chemotherapy in randomised controlled trials (RCTs). These ALK-targeted therapies are currently used in clinical practice and are endorsed in multiple clinical oncology guidelines. OBJECTIVES: To evaluate the safety and efficacy of ALK inhibitors given as monotherapy to treat advanced ALK-rearranged NSCLC. SEARCH METHODS: We conducted electronic searches in the Cochrane Lung Cancer Group Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, and Embase. We also searched conference proceedings from the American Society for Clinical Oncology (ASCO), European Society of Medical Oncology (ESMO), and International Association for the Study of Lung Cancer (IASLC) World Conference on Lung Cancer, as well as the reference lists of retrieved articles. All searches were conducted from 2007 until 7 January 2021. SELECTION CRITERIA: We included RCTs comparing ALK inhibitors with cytotoxic chemotherapy or another ALK inhibitor in individuals with incurable locally advanced or metastatic pathologically confirmed ALK-rearranged NSCLC. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for eligibility, extracted study characteristics and outcome data, and assessed risk of bias using the Cochrane risk of bias tool for each included study. We assessed the certainty of evidence using GRADE. Primary outcomes were progression-free survival (PFS) and adverse events (AE); secondary outcomes were overall survival (OS), OS at one year, overall response rate (ORR) by RECIST (Response Evaluation Criteria in Solid Tumours) criteria, and health-related quality of life (HRQoL). We performed a meta-analysis for all outcomes, where appropriate, using the fixed-effect model. We reported hazard ratios (HR) for PFS, OS, and a composite HRQoL of life outcome (time to deterioration), and risk ratios (RR) for AE, ORR, and one-year OS. We presented 95% confidence intervals (95% CIs) and used the I² statistic to investigate heterogeneity. We planned comparisons of 'ALK inhibitor versus chemotherapy' and 'next-generation ALK inhibitor versus crizotinib' with subgroup analysis by type of ALK inhibitor, line of treatment, and baseline central nervous system involvement. MAIN RESULTS: Eleven studies (2874 participants) met our inclusion criteria: six studies compared an ALK inhibitor (crizotinib, ceritinib, and alectinib) to chemotherapy, and five studies compared a next-generation ALK inhibitor (alectinib, brigatinib, and lorlatinib) to crizotinib. We assessed the evidence for most outcomes as of moderate to high certainty. Most studies were at low risk for selection, attrition, and reporting bias; however, no RCTs were blinded, resulting in a high risk of performance and detection bias for outcomes reliant on subjective measurement. ALK inhibitor versus chemotherapy Treatment with ALK inhibitors resulted in a large increase in PFS compared to chemotherapy (HR 0.45, 95% CI 0.40 to 0.52, 6 RCTs, 1611 participants, high-certainty evidence). This was found regardless of line of treatment. ALK inhibitors may result in no difference in overall AE rate when compared to chemotherapy (RR 1.01, 95% CI 1.00 to 1.03, 5 RCTs, 1404 participants, low-certainty evidence). ALK inhibitors slightly improved OS (HR 0.84, 95% CI 0.72 to 0.97, 6 RCTs, 1611 participants, high-certainty evidence), despite most included studies having a significant number of participants crossing over from chemotherapy to receive an ALK inhibitor after the study period. ALK inhibitors likely increase ORR (RR 2.43, 95% CI 2.16 to 2.75, 6 RCTs, 1611 participants, moderate-certainty evidence) including in measurable baseline brain metastases (RR 4.88, 95% CI 2.18 to 10.95, 3 RCTs, 108 participants) when compared to chemotherapy. ALK inhibitors result in a large increase in the HRQoL measure, time to deterioration (HR 0.52, 95% CI 0.44 to 0.60, 5 RCTs, 1504 participants, high-certainty evidence) when compared to chemotherapy. Next-generation ALK inhibitor versus crizotinib Next-generation ALK inhibitors resulted in a large increase in PFS (HR 0.39, 95% CI 0.33 to 0.46, 5 RCTs, 1263 participants, high-certainty evidence), particularly in participants with baseline brain metastases. Next-generation ALK inhibitors likely result in no difference in overall AE (RR 1.00, 95% CI 0.98 to 1.01, 5 RCTs, 1263 participants, moderate-certainty evidence) when compared to crizotinib. Next-generation ALK inhibitors likely increase OS (HR 0.71, 95% CI 0.56 to 0.90, 5 RCTs, 1263 participants, moderate-certainty evidence) and slightly increase ORR (RR 1.18, 95% CI 1.10 to 1.25, 5 RCTs, 1229 participants, moderate-certainty evidence) including a response in measurable brain metastases (RR 2.45, 95% CI 1.7 to 3.54, 4 RCTs, 138 participants) when compared to crizotinib. Studies comparing ALK inhibitors were conducted exclusively or partly in the first-line setting. AUTHORS' CONCLUSIONS: Next-generation ALK inhibitors including alectinib, brigatinib, and lorlatinib are the preferred first systemic treatment for individuals with advanced ALK-rearranged NSCLC. Further trials are ongoing including investigation of first-line ensartinib. Next-generation inhibitors have not been compared to each other, and it is unknown which should be used first and what subsequent treatment sequence is optimal.

Quantitative Evaluation of Cardiac Cell Interactions and Responses to Cyclic Strain.

The heart has a dynamic mechanical environment contributed by its unique cellular composition and the resultant complex tissue structure. In pathological heart tissue, both the mechanics and cell composition can change and influence each other. As a result, the interplay between the cell phenotype and mechanical stimulation needs to be considered to understand the biophysical cell interactions and organization in healthy and diseased myocardium. In this work, we hypothesized that the overall tissue organization is controlled by varying densities of cardiomyocytes and fibroblasts in the heart. In order to test this hypothesis, we utilized a combination of mechanical strain, co-cultures of different cell types, and inhibitory drugs that block intercellular junction formation. To accomplish this, an image analysis pipeline was developed to automatically measure cell type-specific organization relative to the stretch direction. The results indicated that cardiac cell type-specific densities influence the overall organization of heart tissue such that it is possible to model healthy and fibrotic heart tissue in vitro. This study provides insight into how to mimic the dynamic mechanical environment of the heart in engineered tissue as well as providing valuable information about the process of cardiac remodeling and repair in diseased hearts.

A Study of Gene Expression, Structure, and Contractility of iPSC-Derived Cardiac Myocytes from a Family with Heart Disease due to LMNA Mutation.

Genetic mutations to the Lamin A/C gene (LMNA) can cause heart disease, but the mechanisms making cardiac tissues uniquely vulnerable to the mutations remain largely unknown. Further, patients with LMNA mutations have highly variable presentation of heart disease progression and type. In vitro patient-specific experiments could provide a powerful platform for studying this phenomenon, but the use of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) introduces heterogeneity in maturity and function thus complicating the interpretation of the results of any single experiment. We hypothesized that integrating single cell RNA sequencing (scRNA-seq) with analysis of the tissue architecture and contractile function would elucidate some of the probable mechanisms. To test this, we investigated five iPSC-CM lines, three controls and two patients with a (c.357-2A>G) mutation. The patient iPSC-CM tissues had significantly weaker stress generation potential than control iPSC-CM tissues demonstrating the viability of our in vitro approach. Through scRNA-seq, differentially expressed genes between control and patient lines were identified. Some of these genes, linked to quantitative structural and functional changes, were cardiac specific, explaining the targeted nature of the disease progression seen in patients. The results of this work demonstrate the utility of combining in vitro tools in exploring heart disease mechanics.

Standard-Dose Osimertinib in EGFR-Mutated Non-Small-Cell Lung Adenocarcinoma With Leptomeningeal Disease.

PURPOSE: Leptomeningeal disease (LMD) in epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma is associated with a poor prognosis and limited treatment options. Osimertinib is a potent third-generation EGFR tyrosine kinase inhibitor with confirmed CNS penetration. This study reports on outcomes of patients with EGFR-mutated non-small-cell lung cancer who developed LMD and were subsequently treated with osimertinib. METHODS: We identified patients treated with osimertinib 80 mg PO daily under a compassionate access scheme across nine tertiary Australian institutes between July 2017 and July 2020. Patient demographics, tumor characteristics, and treatment history were collected. Median overall survival, median progression-free survival, disease control rates (DCR), and overall response rates (ORR) were assessed. Kaplan-Meier analysis was performed and descriptive statistics were used. RESULTS: Thirty-nine patients were analyzed of which 74% were female. Exon 19 deletions (49%) and L858R point mutations (41%) were the most common EGFR mutations. Forty-nine percentage of patients were Eastern Cooperative Oncology Group 1. The median duration of osimertinib therapy was 6 months. The extracranial DCR and ORR were 60% and 54%, and the intracranial DCR and ORR were 68% and 53%, respectively. Median overall survival was 10.5 months (95% CI, 8.17 to 15.05 months). CONCLUSION: There are limited treatment options for LMD in EGFR-positive lung cancer, and osimertinib at a dose of 80 mg daily is an active therapeutic option for these patients.

Striated myocyte structural integrity: Automated analysis of sarcomeric z-discs.

As sarcomeres produce the force necessary for contraction, assessment of sarcomere order is paramount in evaluation of cardiac and skeletal myocytes. The uniaxial force produced by sarcomeres is ideally perpendicular to their z-lines, which couple parallel myofibrils and give cardiac and skeletal myocytes their distinct striated appearance. Accordingly, sarcomere structure is often evaluated by staining for z-line proteins such as α-actinin. However, due to limitations of current analysis methods, which require manual or semi-manual handling of images, the mechanism by which sarcomere and by extension z-line architecture can impact contraction and which characteristics of z-line architecture should be used to assess striated myocytes has not been fully explored. Challenges such as isolating z-lines from regions of off-target staining that occur along immature stress fibers and cell boundaries and choosing metrics to summarize overall z-line architecture have gone largely unaddressed in previous work. While an expert can qualitatively appraise tissues, these challenges leave researchers without robust, repeatable tools to assess z-line architecture across different labs and experiments. Additionally, the criteria used by experts to evaluate sarcomeric architecture have not been well-defined. We address these challenges by providing metrics that summarize different aspects of z-line architecture that correspond to expert tissue quality assessment and demonstrate their efficacy through an examination of engineered tissues and single cells. In doing so, we have elucidated a mechanism by which highly elongated cardiomyocytes become inefficient at producing force. Unlike previous manual or semi-manual methods, characterization of z-line architecture using the metrics discussed and implemented in this work can quantitatively evaluate engineered tissues and contribute to a robust understanding of the development and mechanics of striated muscles.

Breast milk paclitaxel excretion following intravenous chemotherapy-a case report.

Breast cancer can be diagnosed during pregnancy and in the peri-partum period, and the potential exposure of a foetus or neonate to chemotherapy is of concern to mothers and clinicians. Paclitaxel is a commonly used agent in breast cancer, but little is known about its excretion in breast milk. Breastfeeding during chemotherapy has been traditionally cautioned against due to the risk of neonatal exposure to chemotherapy agents, however, data are limited. We measured serum and breast milk concentrations of paclitaxel in a 33-year-old woman with an early breast cancer diagnosed during pregnancy and treated with weekly paclitaxel 80 mg/m2. We found breast milk paclitaxel levels drop below the minimum quantifiable dose at 72 h following chemotherapy, with a relative infant dose of 0.091%. Breast milk excretion of paclitaxel following a dose of 80 mg/m2 is negligible at 72 h, and this may be a safe time to recommence breastfeeding following exposure.

Targeting ROS1 Rearrangements in Non-small Cell Lung Cancer: Crizotinib and Newer Generation Tyrosine Kinase Inhibitors.

ROS1 gene rearrangements exist in 1-2% of non-small cell lung cancers, typically occurring in younger, never or light smokers with adenocarcinoma. ROS1 gene fusions are potent oncogenic drivers, the presence of which results in the susceptibility of tumours to ROS1-targeted therapy. Crizotinib was the first tyrosine kinase inhibitor to demonstrate activity in ROS1-rearranged lung cancer, and remains the recommended first-line therapy for patients with advanced ROS1-rearranged non-small cell lung cancer. Despite excellent initial responses to crizotinib, the majority of patients develop disease progression, which may be intracranial or extracranial. Identification of resistance mechanisms to crizotinib, and newer generation tyrosine kinase inhibitors with increased potency against ROS1 and ROS1-resistance mutations, and improved intracranial activity are under evaluation in clinical trials. In this review, we discuss ROS1 rearrangements in non-small cell lung cancer, and provide an update on targeting ROS1-rearranged non-small cell lung cancer with crizotinib and newer generation tyrosine kinase inhibitors.

Flow Decay: A Novel Spirometric Index to Quantify Dynamic Airway Resistance.

BACKGROUND: Dynamic airway resistance from obstructive disease causes a concavity in the mid-expiratory portion of the spirometric flow-volume loop. We developed a simple model to measure the exponential decay in air flow during forced exhalation to quantify the extent of dynamic airway obstruction and facilitate the detection of obstructive airway diseases clinically. METHODS: We calculated flow decay as the slope of volume versus ln(1/flow) in mid-exhalation. We derived the normal range in a derivation group of healthy volunteers in whom spirometry had been performed repeatedly. We validated the derived upper limit of normal (mean + 2 × SD) by using it to distinguish a separate group of healthy subjects (n = 25) from subjects with independently diagnosed reversible airway obstruction (n = 31) and subjects with obstruction, hyperinflation, and air trapping (n = 62). RESULTS: In the derivation group (n = 7), the mean ± SD flow decay was 0.588 ± 0.107 L-1 (upper limit of normal = 0.802 L-1). Flow decay in 23 of 25 healthy subjects in the validation group was below the upper limit of normal. In contrast, it was above the upper limit of normal in 29 of 31 subjects with reversible airway obstruction (sensitivity 94%, 95% CI 79-99%; specificity 92%, 95% CI 74-99%) and in 59 of 62 of subjects with obstruction, hyperinflation, and air trapping (sensitivity 92%, 95% CI 74-99%; specificity 95%, 95% CI 86-99%). CONCLUSIONS: Flow decay distinguished subjects with obstructive lung defects from healthy subjects. It is a straightforward representation of spirometry data that provides a reproducible index to quantify dynamic airway obstruction.

Laryngoscopy during swimming: A novel diagnostic technique to characterize swimming-induced laryngeal obstruction.

Exercise-induced laryngeal obstruction (EILO) is a key differential diagnosis for respiratory symptoms in athletes and is particularly prevalent in aquatic athletes. A definitive diagnosis of EILO is dependent on laryngoscopy, performed continuously, while an athlete engages in the sport that precipitates their symptoms. This report provides the first description of the feasibility of performing continuous laryngoscopy during exercise in a swimming environment. The report describes the methodology and safety of the use of continuous laryngoscopy while swimming. Laryngoscope, 127:2298-2301, 2017.

Physiological and Cognitive Responses to an Antarctic Expedition: A Case Report.

PURPOSE: To assess changes in body composition and monitor cognitive function, subjective well-being, and physiological stress, as measured by salivary hormones and markers of mucosal immunity, during an Antarctic expedition. METHODS: A 36-y-old man (188.2 cm height, 94.5 kg body mass) took part in a world-record attempt. A total-body dual-energy X-ray absorptiometry scan and measurement of 8 skinfolds and 5 girths were performed before and after the expedition. In addition, daily subjective data were recorded (sleep quality, total hours of sleep, energy levels, perceived exertion, mood, muscle soreness, and muscle/joint pain) along with distance covered and hours of physical activity per day. As a measure of cognitive function, the athlete completed a computerized battery of tasks (Axon Sports Cognitive Priming Application) every third morning. Saliva samples were collected before, during, and after the expedition to determine salivary cortisol (sCort), testosterone (sT), alpha amylase (sAA), and secretory immunoglobulin A (sIgA). RESULTS: The athlete lost 5.3 kg body mass and sum of 8 skinfolds decreased from 73 mm to 59 mm from preexpedition to postexpedition. Psychomotor speed declined over the course of the expedition. sT increased and sCort decreased throughout, and sAA and sIgA peaked toward the end of the expedition. CONCLUSIONS: This case study provides novel data about the physiological and cognitive impact of an Antarctic expedition. The findings may inform strategies for future expeditions, allowing individuals undertaking expeditions of this nature to better prepare for success.

Sickness presenteeism in a New Zealand hospital.

AIMS: The aim of this study was to assess the attitudes of hospital clinical staff to acute personal illness. METHODS: A self-reported questionnaire was developed. Four hundred clinical staff employed by the district health board (DHB) who met the inclusion criteria who were randomly selected. Data were collected and analysed using SPSS software. Ethical approval was obtained from the Lower South Regional Ethics Committee and from the DHB Health Research Office. RESULTS: Doctors were more likely to exhibit sickness presenteeism (SP)--i.e. working despite being sick--than any other occupational group at the DHB. Two main reasons were given for not taking sick leave: staff did not believe they were unwell enough to justify taking leave and they did not want to increase the workload of others. The majority of study participants would not contact anyone for advice about whether to take leave. CONCLUSION: This study provides evidence that SP, especially in doctors, is prevalent in the DHB and is similar to findings from elsewhere. Low rates of clinical staff contacting someone for advice on coming to work whilst ill could be targeted to improve infection control.

The specificity of training prescription and physiological assessment: a review.

The aims in this review are: (1) to identify physiological determinants of performance; (2) to consider training specificity by examining aerobic, team and racket sports, strength and power activities, and cross-training and concurrent training methods; and (3) to evaluate the role of specificity in the physiological assessment of performance determinants. Assessment of the physiological determinants of performance is an integral part of sports science support for elite athletes. Laboratory and field-based physiological assessments are fundamental elements in profiling athletes, assessing training adaptations, and interrogating programme efficacy. The relatively small and highly specific adaptations associated with high-performance training call for valid, reliable, and sensitive methods of assessment. Recent advances in the physiological assessment of athletes have led to the development of a plethora of laboratory and field-based procedures. In the assessment of the athlete, there is a tension between the high reliability and low ecological validity of laboratory assessments and the low reliability and high validity of field-based methods. In an attempt to enhance ecological validity of training and physiological assessment, various sports-specific ergometers have been designed. This development has helped to match fitness assessment procedures to the demands of the sport concerned.