Results of the Meso-ORIGINS feasibility study regarding collection of matched benign-mesothelioma tissue pairs by longitudinal surveillance.

OBJECTIVES: To assess key elements of the design for Meso-ORIGINS (Mesothelioma Observational study of RIsk prediction and Generation of paired benign-meso tissue samples, Including a Nested MRI Substudy), an ambitious, UK-wide, prospective study that will collect ≥63 matched benign-mesothelioma tissue pairs through longitudinal surveillance and repeat biopsy of patients with asbestos-associated pleural inflammation (AAPI). DESIGN: A multicentre, mixed-methods feasibility study, comprising a prospective observational element, evaluating recruitment feasibility, technical feasibility of repeat local anaesthetic thoracoscopy (LAT) and patient acceptability, and a retrospective cohort study focused on AAPI-mesothelioma evolution rate, informing sample size. SETTING: 4 UK pleural disease centres (February 2019-January 2020). PARTICIPANTS: Patients with AAPI (history or typical imaging plus appropriate pleural histology) were eligible for both elements. In August 2019, eligibility for the prospective element was broadened, including addition of radiological AAPI for technical feasibility and patient acceptability endpoints only. Retrospective cases required ≥2 years follow-up. OUTCOME MEASURES: A prospective recruitment target was set a priori at 27 histological AAPI cases (or 14 in any 6 months). Technical feasibility and patient acceptability were determined at 6-month follow-up by thoracic ultrasound surrogates and questionnaires, respectively. Retrospective malignant pleural mesothelioma evolution rate was defined by proportion (95% CI). Baseline predictors of evolution were identified using logistic regression. RESULTS: 296 patients with AAPI (39 prospective, 257 retrospective) were recruited/selected. 21/39 prospective recruits were histologically diagnosed (target n=27). Repeat LAT was technically feasible and acceptable in 13/28 (46%) and 24/36 (67%) cases with complete follow-up data. Mesothelioma evolution was confirmed histologically in 36/257 retrospective cases (14% (95% CI 10.3% to 18.8%)) and associated with malignant CT features (OR 4.78 (95% CI 2.36 to 9.86)) and age (OR 1.06 (95% CI 1.02 to 1.12)). CONCLUSIONS: Our initial eligibility criteria were too narrow. Meso-ORIGINS will recruit a broader cohort, including prevalent cases, any biopsy type and patients with malignant CT features. A range of rebiopsy techniques will be allowed, accounting for technical and patient factors. The sample size has been reduced to 500. TRIAL REGISTRATION NUMBER: ISRCTN12840870.

Artificial extracellular matrix scaffolds of mobile molecules enhance maturation of human stem cell-derived neurons.

Human induced pluripotent stem cell (hiPSC) technologies offer a unique resource for modeling neurological diseases. However, iPSC models are fraught with technical limitations including abnormal aggregation and inefficient maturation of differentiated neurons. These problems are in part due to the absence of synergistic cues of the native extracellular matrix (ECM). We report on the use of three artificial ECMs based on peptide amphiphile (PA) supramolecular nanofibers. All nanofibers display the laminin-derived IKVAV signal on their surface but differ in the nature of their non-bioactive domains. We find that nanofibers with greater intensity of internal supramolecular motion have enhanced bioactivity toward hiPSC-derived motor and cortical neurons. Proteomic, biochemical, and functional assays reveal that highly mobile PA scaffolds caused enhanced ß1-integrin pathway activation, reduced aggregation, increased arborization, and matured electrophysiological activity of neurons. Our work highlights the importance of designing biomimetic ECMs to study the development, function, and dysfunction of human neurons.

The diagnostic pathway in lung cancer patients with best supportive care decisions: are there lessons to be learnt?

INTRODUCTION: A proportion of patients with lung cancer will not be suitable for anti-cancer treatment and are managed with best supportive care (BSC). The aim of this retrospective case series analysis was to critically review the use of diagnostic and staging investigations in patients who were ultimately managed with BSC. METHODS: A retrospective review of all lung cancer patients with a multidisciplinary team outcome of BSC from 01 June 2018 to 01 June 2019 was performed. Patients were categorised into those with an early BSC decision and those that underwent further investigations prior to a BSC decision (investigations beyond initial computed tomography (CT)). Patient demographics, clinical characteristics and outcomes were collated and analysed. RESULTS: Seventy-seven lung cancer patients managed with BSC were identified. Patients were elderly (average age 79 years), functionally limited (80% World Health Organization performance status ≥3), frail (70% clinical frailty score ≥6) and had advanced stage disease (90% stage III/IV). Thirty-one (40%) underwent further investigations beyond the initial CT prior to the BSC decision. The most common types of further investigations were endobronchial ultrasound-guided transbronchial needle aspiration (27/31; 74%), positron emission tomography - CT (18/31; 45%) and CT-guided lung biopsy (7/31; 23%). This is despite high levels of consultant chest physician review at first assessment (71%), cancer nurse specialist involvement (97%), specialist palliative care involvement (65%), a high pathological confirmation rate of sampling procedures (89%) and adequacy of molecular testing. The most common reason for a BSC recommendation was a lack of fitness for systemic therapy (17/31; 55%). Six out of thirty-one (19%) patients deteriorated rapidly and died on the cancer pathway and 5/31 (16%) patients had inadequate renal function for systemic anti-cancer treatment. There was low utilisation of serum epidermal growth factor receptor mutation testing across the study cohort (2/77; 3%). DISCUSSION: In an older, functionally limited and frail patient with lung cancer, there is a risk of over-investigation. Impaired renal function is an important clinical factor to identify early to support discussions in this cohort. There will always be an unavoidable proportion of patients that undergo further investigations (often in search of rare targetable mutations) and are then ultimately recommended for best supportive care; such cases could form the basis of specific review and learning for lung cancer services.

'Channeling' therapeutic discovery for epileptic encephalopathy through iPSC technologies.

Induced pluripotent stem cell (iPSC) and gene editing technologies have revolutionized the field of in vitro disease modeling, granting us access to disease-pertinent human cells of the central nervous system. These technologies are particularly well suited for the study of diseases with strong monogenic etiologies. Epilepsy is one of the most common neurological disorders in children, with approximately half of all genetic cases caused by mutations in ion channel genes. These channelopathy-associated epilepsies are clinically diverse, mechanistically complex, and hard to treat. Here, we review the genetic links to epilepsy, the opportunities and challenges of iPSC-based approaches for developing in vitro models of channelopathy-associated disorders, the available tools for effective phenotyping of iPSC-derived neurons, and discuss the potential therapeutic approaches for these devastating diseases.

Dyshomeostatic modulation of Ca2+-activated K+ channels in a human neuronal model of KCNQ2 encephalopathy.

Mutations in KCNQ2, which encodes a pore-forming K+ channel subunit responsible for neuronal M-current, cause neonatal epileptic encephalopathy, a complex disorder presenting with severe early-onset seizures and impaired neurodevelopment. The condition is exceptionally difficult to treat, partially because the effects of KCNQ2 mutations on the development and function of human neurons are unknown. Here, we used induced pluripotent stem cells (iPSCs) and gene editing to establish a disease model and measured the functional properties of differentiated excitatory neurons. We find that patient iPSC-derived neurons exhibit faster action potential repolarization, larger post-burst afterhyperpolarization and a functional enhancement of Ca2+-activated K+ channels. These properties, which can be recapitulated by chronic inhibition of M-current in control neurons, facilitate a burst-suppression firing pattern that is reminiscent of the interictal electroencephalography pattern in patients. Our findings suggest that dyshomeostatic mechanisms compound KCNQ2 loss-of-function leading to alterations in the neurodevelopmental trajectory of patient iPSC-derived neurons.

Homozygous deletion of CDKN2A in malignant mesothelioma: Diagnostic utility, patient characteristics and survival in a UK mesothelioma centre.

BACKGROUND: Detection of homozygous deletion of the p16 gene (CDKN2A) by fluorescence in situ hybridization (FISH) has been investigated as an ancillary technique in the diagnosis of malignant mesothelioma. METHOD: This retrospective study reviewed the results of all p16 FISH tests performed at a regional mesothelioma centre from February 2012 to November 2019 in cases of possible mesothelioma to examine the diagnostic utility of this test as well as patients characteristics and survival in p16 FISH positive mesothelioma versus p16 FISH negative mesothelioma. RESULTS: P16 FISH testing was requested in 216 pathological samples in the study period. The test failure rate was 4% (10/216). Median time from request to result was 10 days (IQR 7-13, range 1-30). The sensitivity, specificity, NPV and PPV were 60 %, 100 %, 39 % and 100 % respectively. There were no false positive results and this genetic aberration was only detected in cases of mesothelioma. The prevalence of p16 FISH positive mesothelioma was higher in cytological specimens compared to histological specimens (75 % vs 58 %, p = 0.03) and lower in women compared to men (33 % vs 66 %, p = 0.003). P16 FISH positive mesothelioma was associated with significantly worse survival (median overall survival 285 vs 339 days, p = 0.0018). This remained significant after adjusting for confounding variables (OR 4.4, 95 %CI 1.84-11.14, p = 0.001). CONCLUSIONS: In this study, 60 % of mesotheliomas harbour a homozygous deletion of CDKN2A and can be accurately, reliably and efficiently identified by p16 FISH testing. This test can be embedded within routine practice in mesothelioma pathways to enhance diagnostic accuracy.

Impact of support initiatives on retaining rural general practitioners.

OBJECTIVE: This study aimed to evaluate the impact of the Dr DOC program, a rural doctor workforce support program, which consists of social and psychological support and practical interventions, on the well-being and retention of rural GPs. DESIGN: Rural GPs were assessed on different aspects of well-being and their intentions to leave rural general practice, and these were compared with similar data collected two years prior. SETTING: Rural general practices in South Australia. PARTICIPANTS: Two hundred and twenty-one rural GPs (55% of South Australian rural GP workforce). MAIN OUTCOME MEASURES: GPs completed a questionnaire assessing their levels of support, intention to leave rural practice, use of the dr doc program, and psychological health. RESULTS: Improvements were found in the support networks and in the physical and emotional health of rural GPs from time 1 to time 2. There was also a reduction in the number of GPs wanting to leave rural general practice in the short to medium term (from 30% to 25%). CONCLUSIONS: The initial study in this series suggested that improving psychological well-being might influence rural GPs' intentions to leave rural practice. The current study confirms these suggestions by demonstrating that programs targeted at psychological and physical well-being do indeed impact on rural GPs' intentions to leave. The results of this study highlight the role of psychological well-being in retaining rural GPs and emphasise the value of developing psychologically based programs to not only boost the physical and mental health of GPs, but also to reduce departure from rural areas.

Relationship between dieting to lose weight and the functioning of the central executive.

The study investigated the impact of weight-loss dieting on the four identified functions of the central executive of working memory: dual-task performance, random generation, task switching and activation of long-term memory. Participants were 32 female current dieters and 32 female non-dieters who completed four well-established cognitive tasks designed to tap each specific function. Participants also completed tasks designed to load on the phonological loop and visuo-spatial sketch pad working memory systems, as well as self-report measures of depressed affect and preoccupying cognitions. Dieters performed more poorly than non-dieters on all central executive measures except random generation. These dieting-related differences were most evident on moderately complex trials, and were partially mediated by preoccupying thoughts about food, weight and body shape, but not by BMI or depressed affect. It was concluded that weight-loss dieting has a relatively global impact on central executive functioning and thus has wide-ranging cognitive consequences.

Microhomology-dependent end joining and repair of transposon-induced DNA hairpins by host factors in Saccharomyces cerevisiae.

The maize, cut-and-paste transposon Ac/Ds is mobile in Saccharomyces cerevisiae, and DNA sequences of repair products provide strong genetic evidence that hairpin intermediates form in host DNA during this transposition, similar to those formed for V(D)J coding joints in vertebrates. Both DNA strands must be broken for Ac/Ds to excise, suggesting that double-strand break (DSB) repair pathways should be involved in repair of excision sites. In the absence of homologous template, as expected, Ac excisions are repaired by nonhomologous end joining (NHEJ) that can involve microhomologies close to the broken ends. However, unlike repair of endonuclease-induced DSBs, repair of Ac excisions in the presence of homologous template occurs by gene conversion only about half the time, the remainder being NHEJ events. Analysis of transposition in mutant yeast suggests roles for the Mre11/Rad50 complex, SAE2, NEJ1, and the Ku complex in repair of excision sites. Separation-of-function alleles of MRE11 suggest that its endonuclease function is more important in this repair than either its exonuclease or Rad50-binding properties. In addition, the interstrand cross-link repair gene PSO2 plays a role in end joining hairpin ends that is not seen in repair of linearized plasmids and may be involved in positioning transposase cleavage at the transposon ends.