Myc Cooperates with Ras by Programming Inflammation and Immune Suppression.

The two oncogenes KRas and Myc cooperate to drive tumorigenesis, but the mechanism underlying this remains unclear. In a mouse lung model of KRasG12D-driven adenomas, we find that co-activation of Myc drives the immediate transition to highly proliferative and invasive adenocarcinomas marked by highly inflammatory, angiogenic, and immune-suppressed stroma. We identify epithelial-derived signaling molecules CCL9 and IL-23 as the principal instructing signals for stromal reprogramming. CCL9 mediates recruitment of macrophages, angiogenesis, and PD-L1-dependent expulsion of T and B cells. IL-23 orchestrates exclusion of adaptive T and B cells and innate immune NK cells. Co-blockade of both CCL9 and IL-23 abrogates Myc-induced tumor progression. Subsequent deactivation of Myc in established adenocarcinomas triggers immediate reversal of all stromal changes and tumor regression, which are independent of CD4+CD8+ T cells but substantially dependent on returning NK cells. We show that Myc extensively programs an immune suppressive stroma that is obligatory for tumor progression.

Safety and efficacy of avalglucosidase alfa in individuals with infantile-onset Pompe disease enrolled in the phase 2, open-label Mini-COMET study: The 6-month primary analysis report.

PURPOSE: Mini-COMET (NCT03019406; Sanofi) is a phase 2, open-label, ascending-dose, 3-cohort study, evaluating avalglucosidase alfa safety, pharmacokinetics, and efficacy in individuals with infantile-onset Pompe disease aged <18 years who previously received alglucosidase alfa and showed clinical decline (cohorts 1 and 2) or suboptimal response (cohort 3). METHODS: During a 25-week primary analysis period, cohorts 1 and 2 received avalglucosidase alfa 20 and 40 mg/kg every other week, respectively, for 6 months, whereas cohort 3 individuals were randomized (1:1) to receive avalglucosidase alfa 40 mg/kg every other week or alglucosidase alfa (current stable dose) for 6 months. RESULTS: In total, 22 individuals were enrolled (cohort 1 [n = 6], cohort 2 [n = 5], cohort 3-avalglucosidase alfa [n = 5], and cohort 3-alglucosidase alfa [n = 6]). Median treatment compliance was 100%. None of the individuals discontinued treatment or died. Percentages of individuals with treatment-emergent adverse events were similar across dose and treatment groups. No serious or severe treatment-related treatment-emergent adverse events occurred. Trends for better motor function from baseline to week 25 were observed for 40 mg/kg every other week avalglucosidase alfa compared with either 20 mg/kg every other week avalglucosidase alfa or alglucosidase alfa up to 40 mg/kg weekly. CONCLUSION: These data support the positive clinical effect of avalglucosidase alfa in patients with infantile-onset Pompe disease previously declining on alglucosidase alfa.

Acute Severe Behavioral Disturbance Requiring Parenteral Sedation in Pediatric Mental Health Presentations to Emergency Medical Services: A Retrospective Chart Review.

STUDY OBJECTIVES: To describe the epidemiological factors of mental health presentations in young people to emergency medical services (EMS) and define those experiencing acute severe behavioral disturbance by reviewing parenteral sedation use. METHODS: We performed a retrospective review of records of EMS attendance for young people (aged <18 years) with mental health presentations between July 2018 and June 2019 to a statewide EMS system in Australia of a population of 6.5 million persons. In addition, epidemiological data and information about parenteral sedation for acute severe behavioral disturbance and any adverse events were extracted from the records and analyzed. RESULTS: A total of 7,816 patients had mental health presentations with a median age of 15 years (IQR 14-17). The majority (60%) were female. These presentations accounted for 14% of all pediatric presentations to EMS. Out of them, 612 (8%) received parenteral sedation for acute severe behavioral disturbance. A number of factors were associated with increased odds of parenteral sedative medication being used, including autism spectrum disorder (odds ratio [OR] 3.3; confidence interval [CI], 2.7 to 3.9), posttraumatic stress disorder (OR 2.8; CI, 2.2 to 3.5) and intellectual disability (OR 3.6; CI, 2.6 to 4.8). The majority (460, 75%) of young people received midazolam as their first-line medication, with the remaining patients being provided ketamine (152, 25%). No serious adverse events were noted. CONCLUSION: Mental health conditions were a common presentation to EMS. A history of autism spectrum disorder, posttraumatic stress disorder, or an intellectual disability increased the odds of receiving parenteral sedation for acute severe behavioral disturbance. Sedation appears generally safe in the out-of-hospital setting.

The characteristics of SARS-CoV-2-positive children in Australian hospitals: a PREDICT network study.

OBJECTIVES: To examine the clinical characteristics and short term outcomes for children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections who presented to Australian hospitals during 2020 and 2021. DESIGN, SETTING: Retrospective case review study in nineteen hospitals of the Paediatric Research in Emergency Departments International Collaborative (PREDICT) network from all Australian states and territories, including seven major paediatric tertiary centres and eight Victorian hospitals. PARTICIPANTS: SARS-CoV-2-positive people under 18 years of age who attended emergency departments or were admitted to hospital during 1 February 2020 - 31 December 2021. MAIN OUTCOME MEASURES: Epidemiological and clinical characteristics, by hospital care type (emergency department [ED] or inpatient care). RESULTS: A total of 1193 SARS-CoV-2-positive children and adolescents (527 girls, 44%) attended the participating hospitals (107 in 2020, 1086 in 2021). Their median age was 3.8 years (interquartile range [IQR], 0.8-11.4 years); 63 were Aboriginal or Torres Strait Islander people (5%). Other medical conditions were recorded for 293 children (25%), including asthma (86, 7%) and premature birth (68, 6%). Medical interventions were not required during 795 of 1181 ED presentations (67%); children were discharged directly home in 764 cases (65%) and admitted to hospital in 282 (24%; sixteen to intensive care units). The 384 admissions to hospital (including 102 direct admissions) of 341 children (25 infants under one month of age) included 23 to intensive care (6%); the median length of stay was three days (IQR, 1-9 days). Medical interventions were not required during 261 admissions (68%); 44 children received respiratory support (11%) and 21 COVID-19-specific treatments, including antiviral and biologic agents (5%). Being under three months of age (v one year to less than six years: odds ratio [OR], 2.6; 95% confidence interval [CI], 1.7-4.0) and pre-existing medical conditions (OR, 2.5; 95% CI, 1.9-3.2) were the major predictors of hospital admission. Two children died, including one without a known pre-existing medical condition. CONCLUSION: During 2020 and 2021, most SARS-CoV-2-positive children and adolescents who presented to participating hospitals could be managed as outpatients. Outcomes were generally good, including for those admitted to hospital.

Cognate restriction of transposition by piggyBac-like proteins.

Mobile genetic elements have been harnessed for gene transfer for a wide variety of applications including generation of stable cell lines, recombinant protein production, creation of transgenic animals, and engineering cell and gene therapy products. The piggyBac transposon family includes transposase or transposase-like proteins from a variety of species including insect, bat and human. Recently, human piggyBac transposable element derived 5 (PGBD5) protein was reported to be able to transpose piggyBac transposons in human cells raising possible safety concerns for piggyBac-mediated gene transfer applications. We evaluated three piggyBac-like proteins across species including piggyBac (insect), piggyBat (bat) and PGBD5 (human) for their ability to mobilize piggyBac transposons in human cells. We observed a lack of cross-species transposition activity. piggyBac and piggyBat activity was restricted to their cognate transposons. PGBD5 was unable to mobilize piggyBac transposons based on excision, colony count and plasmid rescue analysis, and it was unable to bind piggyBac terminal repeats. Within the piggyBac family, we observed a lack of cross-species activity and found that PGBD5 was unable to bind, excise or integrate piggyBac transposons in human cells. Transposition activity appears restricted within species within the piggyBac family of mobile genetic elements.

Qualitative study of emergency clinicians to inform a national guideline on the management of children with mild-to-moderate head injuries.

BACKGROUND: Head injury is a common reason children present to EDs. Guideline development to improve care for paediatric head injuries should target the information needs of ED clinicians and factors influencing its uptake. METHODS: We conducted semi-structured qualitative interviews (November 2017-November 2018) with a stratified purposive sample of ED clinicians from across Australia and New Zealand. We identified clinician information needs, used the Theoretical Domains Framework (TDF) to explore factors influencing the use of head CT and clinical decision rules/guidelines in CT decision-making, and explored ways to improve guideline uptake. Two researchers coded the interview transcripts using thematic content analysis. RESULTS: A total of 43 clinicians (28 doctors, 15 nurses), from 19 hospitals (5 tertiary, 8 suburban, 6 regional/rural) were interviewed. Clinicians sought guidance for scenarios including ED management of infants, children with underlying medical issues, delayed or representations and potential non-accidental injuries. Improvements to the quality and content of discharge communication and parental discussion materials were suggested. Known risks of radiation from head CTs has led to a culture of observation over use of CT in Australasia (TDF domain: beliefs about consequences). Formal and informal policies have resulted in senior clinicians making most head CT decisions in children (TDF domain: behavioural regulation). Senior clinicians consider their gestalt to be more accurate and outperform existing guidance (TDF domain: beliefs about capabilities), although they perceive guidelines as useful for training and supporting junior staff. Summaries, flow charts, publication in ED-specific journals and scripted training materials were suggestions to improve uptake. CONCLUSION: Information needs of ED clinicians, factors influencing use of head CT in children with head injuries and the role of guidelines were identified. These findings informed the scope and implementation strategies for an Australasian guideline for mild-to-moderate head injuries in children.

Adverse effects of E-cigarettes on head, neck, and oral cells: A systematic review.

BACKGROUND: E-cigarette sales in the United States (US) are projected to reach 16.5 billion by 2024 according to market analysis. Six deaths and 450 lung illnesses have been linked to e-cigarette use. To our knowledge, a systematic review of the adverse effects of e-cigarettes on head, neck, and oral cells does not exist. This review aimed to conduct a systematic review of current literature to determine whether e-cigarettes caused adverse effects on cells of the head, neck, and oral cavity. METHODS: Five databases including Medline, Dentistry and Oral Sciences, CINAHL, CAPLUS, Web of Science, and gray literature were searched for articles any time up to December 2020. Using Rayyan software, two-independent researchers screened 233 articles and extracted 41 for further investigation. Based on the inclusion criteria, 18 articles were eligible for this review. RESULTS: Aberrant morphology, cytotoxicity, oxidative stress, reduced viability, delayed fibroblast migration, and genotoxicity were statistically significant when the head, neck, and oral cells were exposed to e-cigarettes. Of note, most articles in this systematic review found cigarette smoke to be significantly more toxic to head, neck, and oral cells than e-cigarettes. CONCLUSIONS: E-cigarettes are implicated in adverse effects on head, neck, and oral cells, yet very few have been tested against these cells. More longitudinal studies using a wider variety of e-cigarettes are necessary before we can determine their total adverse effects. Future research must also investigate chronic e-cigarette use and if it leads to periodontal disease and/or head, neck, or oral cancer.

Environmentally-induced sex reversal in fish with chromosomal vs. polygenic sex determination.

Sex ratio depends on sex determination mechanisms and is a key demographic parameter determining population viability and resilience to natural and anthropogenic stressors. There is increasing evidence that the environment can alter sex ratio even in genetically sex-determined species (GSD), as elevated temperature can cause female-to-male sex reversal (neomales). Alarmingly, neomales are being discovered in natural populations of several fish, amphibian and reptile species worldwide. Understanding the basis of neomale development is important for conservation biology. Among GSD species, it is unknown whether those with chromosomal sex determination (CSD), the most common system, will better resist the influence of high temperature than those with polygenic sex determination (PSD). Here, we compared the effects of elevated temperature in two wild zebrafish strains, Nadia (NA) and Ekkwill (EKW), which have CSD with a ZZ/ZW system, against the AB laboratory strain, which has PSD. First, we uncovered novel sex genotypes and the results showed that, at control temperature, the masculinization rate roughly doubled with the addition of each Z chromosome, while some ZW and WW fish of the wild strains became neomales. Surprisingly, we found that at elevated temperatures WW fish were just as likely as ZW fish to become neomales and that all strains were equally susceptible to masculinization. These results demonstrate that the Z chromosome is not essential for male development and that the dose of W buffers masculinization at the control temperature but not at elevated temperature. Furthermore, at the elevated temperature the testes of neomales, but not of normal males, contained more spermatozoa than at the control temperature. Our results show in an unprecedented way that, in a global warming scenario, CSD species may not necessarily be better protected against the masculinizing effect of elevated temperature than PSD species, and reveal genotype-by-temperature interactions in male sex determination and spermatogenesis.

Can targeted interventions change the factors influencing variation in management of infants with bronchiolitis? A survey of Australian and New Zealand clinicians: A paediatric research in emergency departments international collaborative (PREDICT) study.

AIM: This study aimed to determine whether targeted interventions, proven to be effective at improving evidence-based bronchiolitis management, changed factors previously found to influence variation in bronchiolitis management. METHODS: This survey assessed change in factors influencing clinicians' (nurses and doctors) bronchiolitis management at baseline and post-intervention in a cluster randomised controlled trial of targeted, theory-informed interventions aiming to de-implement non-evidence-based bronchiolitis management (no use of chest X-ray, salbutamol, antibiotics, glucocorticoids and adrenaline). Survey questions addressed previously identified factors influencing bronchiolitis management from six Theoretical Domains Framework domains (knowledge; skills; beliefs about consequences; social/professional role and identity; environmental context and resources; social influences). Data analysis was descriptive. RESULTS: A total of 1958 surveys (baseline = 996; post-intervention = 962) were completed by clinicians from the emergency department and paediatric inpatient units from 26 hospitals (intervention = 13; control = 13). Targeted bronchiolitis interventions significantly increased knowledge of the Australasian Bronchiolitis Guideline (intervention clinicians = 74%, control = 39%, difference = 34.7%, 95% confidence interval (CI) = 25.6-43.8%), improved skills in diagnosing (intervention doctors = 89%, control = 76%, difference = 12.6%, 95% CI = 6.2-19%) and managing bronchiolitis (intervention doctors = 87%, control = 76%, difference = 9.9%, 95% CI = 3.7-16.1%), positively influenced both beliefs about consequences regarding salbutamol use (intervention clinicians = 49%, control = 29%, difference = 20.3%, 95% CI = 13.2-27.4%) and nurses questioning non-evidence-based bronchiolitis management (chest X-ray: intervention = 71%, control = 51%, difference = 20.8%, 95% CI = 11.4-30.2%; glucocorticoids: intervention = 64%, control = 40%, difference = 21.9%, 95% CI = 10.4-33.5%) (social/professional role and identity). A 14% improvement in evidence-based bronchiolitis management favouring intervention hospitals was demonstrated in the cluster randomised controlled trial. CONCLUSION: Targeted interventions positively changed factors influencing bronchiolitis management resulting in improved evidence-based bronchiolitis care. This study has important implications for improving bronchiolitis management and future development of interventions to de-implement low-value care.

Sustainability of evidence-based practices in the management of infants with bronchiolitis in hospital settings - a PREDICT study protocol.

BACKGROUND: Understanding how and why de-implementation of low-value practices is sustained remains unclear. The Paediatric Research in Emergency Departments International CollaboraTive (PREDICT) Bronchiolitis Knowledge Translation (KT) Study was a cluster randomised controlled trial conducted in 26 Australian and New Zealand hospitals (May-November 2017). Results showed targeted, theory-informed interventions (clinical leads, stakeholder meetings, train-the-trainer workshop, targeted educational package, audit/feedback) were effective at reducing use of five low-value practices for bronchiolitis (salbutamol, glucocorticoids, antibiotics, adrenaline and chest x-ray) by 14.1% in acute care settings. The primary aim of this study is to determine the sustainability (continued receipt of benefits) of these outcomes at intervention hospitals two-years after the removal of study supports. Secondary aims are to determine sustainability at one-year after removal of study support at intervention hospitals; improvements one-and-two years at control hospitals; and explore factors that influence sustainability at intervention hospitals and contribute to improvements at control hospitals. METHODS: A mixed-methods study design. The quantitative component is a retrospective medical record audit of bronchiolitis management within 24 hours of emergency department (ED) presentations at 26 Australian (n = 20) and New Zealand (n = 6) hospitals, which participated in the PREDICT Bronchiolitis KT Study. Data for a total of 1800 infants from intervention and control sites (up to 150 per site) will be collected to determine if improvements (i.e., no use of all five low-value practices) were sustained two- years (2019) post-trial (primary outcome; composite score); and a further 1800 infants from intervention and control sites will be collected to determine sustained improvements one- year (2018) post-trial (secondary outcome). An a priori definition of sustainability will be used. The qualitative component will consist of semi-structured interviews with three to five key emergency department and paediatric inpatient medical and nursing staff per site (total n = 78-130). Factors that may have contributed to sustaining outcomes and/or interventions will be explored and mapped to an established sustainability framework. DISCUSSION: This study will improve our understanding of the sustainability of evidence-based bronchiolitis management in infants. Results will also advance implementation science research by informing future de-implementation strategies to reduce low-value practices and sustain practice change in paediatric acute care. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry No: ACTRN12621001287820.

Heterogeneity of Myc expression in breast cancer exposes pharmacological vulnerabilities revealed through executable mechanistic modeling.

Cells with higher levels of Myc proliferate more rapidly and supercompetitively eliminate neighboring cells. Nonetheless, tumor cells in aggressive breast cancers typically exhibit significant and stable heterogeneity in their Myc levels, which correlates with refractoriness to therapy and poor prognosis. This suggests that Myc heterogeneity confers some selective advantage on breast tumor growth and progression. To investigate this, we created a traceable MMTV-Wnt1-driven in vivo chimeric mammary tumor model comprising an admixture of low-Myc- and reversibly switchable high-Myc-expressing clones. We show that such tumors exhibit interclonal mutualism wherein cells with high-Myc expression facilitate tumor growth by promoting protumorigenic stroma yet concomitantly suppress Wnt expression, which renders them dependent for survival on paracrine Wnt provided by low-Myc-expressing clones. To identify any therapeutic vulnerabilities arising from such interdependency, we modeled Myc/Ras/p53/Wnt signaling cross talk as an executable network for low-Myc, for high-Myc clones, and for the 2 together. This executable mechanistic model replicated the observed interdependence of high-Myc and low-Myc clones and predicted a pharmacological vulnerability to coinhibition of COX2 and MEK. This was confirmed experimentally. Our study illustrates the power of executable models in elucidating mechanisms driving tumor heterogeneity and offers an innovative strategy for identifying combination therapies tailored to the oligoclonal landscape of heterogenous tumors.

Implementation of smart supportive dementia technology in a hospital transitional care setting using human-centred design.

Supportive smart home technology, for older adults living with dementia and their informal care partners, has shown some benefits in private homes. In this study, a supportive smart home system is being implemented in a hospital alternative level of care setting. This case report describes how a team of researchers and healthcare managers are navigating the complexities of a hospital setting, using human-centred design and implementation strategies, to facilitate the implementation and adoption of the technology.

The characteristics of SARS-CoV-2-positive children who presented to Australian hospitals during 2020: a PREDICT network study.

OBJECTIVES: To examine the epidemiological and clinical characteristics of SARS-CoV-2-positive children in Australia during 2020. DESIGN, SETTING: Multicentre retrospective study in 16 hospitals of the Paediatric Research in Emergency Departments International Collaborative (PREDICT) network; eleven in Victoria, five in four other Australian states. PARTICIPANTS: Children aged 0-17 years who presented to hospital-based COVID-19 testing clinics, hospital wards, or emergency departments during 1 February - 30 September 2020 and who were positive for SARS-CoV-2. MAIN OUTCOME MEASURES: Epidemiological and clinical characteristics of children positive for SARS-CoV-2. RESULTS: A total of 393 SARS-CoV-2-positive children (181 girls, 46%) presented to the participating hospitals (426 presentations, including 131 to emergency departments [31%]), the first on 3 February 2020. Thirty-three children presented more than once (8%), including two who were transferred to participating tertiary centres (0.5%). The median age of the children was 5.3 years (IQR, 1.9-12.0 years; range, 10 days to 17.9 years). Hospital admissions followed 51 of 426 presentations (12%; 44 children), including 17 patients who were managed remotely by hospital in the home. Only 16 of the 426 presentations led to hospital medical interventions (4%). Two children (0.5%) were diagnosed with the paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS). CONCLUSION: The clinical course for most SARS-CoV-2-positive children who presented to Australian hospitals was mild, and did not require medical intervention.

Development of targeted, theory-informed interventions to improve bronchiolitis management.

BACKGROUND: Despite international guidelines providing evidence-based recommendations on appropriate management of infants with bronchiolitis, wide variation in practice occurs. This results in infants receiving care of no benefit, with associated cost and is potentially harmful. Theoretical frameworks are increasingly used to develop interventions, utilising behaviour change techniques specifically chosen to target factors contributing to practice variation, with de-implementation often viewed as harder than implementing. This paper describes the stepped process using the Theoretical Domains Framework (TDF) to develop targeted, theory-informed interventions which subsequently successfully improved management of infants with bronchiolitis by de-implementing ineffective therapies. Explicit description of the process and rationale used in developing de-implementation interventions is critical to dissemination of these practices into real world clinical practice. METHODS: A stepped approach was used: (1) Identify evidence-based recommendations and practice variation as targets for change, (2) Identify factors influencing practice change (barriers and enablers) to be addressed, and (3) Identification and development of interventions (behaviour change techniques and methods of delivery) addressing influencing factors, considering evidence of effectiveness, feasibility, local relevance and acceptability. The mode of delivery for the intervention components was informed by evidence from implementation science systematic reviews, and setting specific feasibility and practicality. RESULTS: Five robust evidence-based management recommendations, targeting the main variation in bronchiolitis management were identified: namely, no use of chest x-ray, salbutamol, glucocorticoids, antibiotics, and adrenaline. Interventions developed to target recommendations addressed seven TDF domains (identified following qualitative clinician interviews (n = 20)) with 23 behaviour change techniques chosen to address these domains. Final interventions included: (1) Local stakeholder meetings, (2) Identification of medical and nursing clinical leads, (3) Train-the-trainer workshop for all clinical leads, (4) Local educational materials for delivery by clinical leads, (5) Provision of tools and materials targeting influencing factors, and prompting recommended behaviours, and (6) Audit and feedback. CONCLUSION: A stepped approach based on theory, evidence and issues of feasibility, local relevance and acceptability, was successfully used to develop interventions to improve management of infants with bronchiolitis. The rationale and content of interventions has been explicitly described allowing others to de-implement unnecessary bronchiolitis management, thereby improving care.

Process evaluation of a cluster randomised controlled trial to improve bronchiolitis management - a PREDICT mixed-methods study.

BACKGROUND: Bronchiolitis is the most common reason for hospitalisation in infants. All international bronchiolitis guidelines recommend supportive care, yet considerable variation in practice continues with infants receiving non-evidence based therapies. We developed six targeted, theory-informed interventions; clinical leads, stakeholder meeting, train-the-trainer, education delivery, other educational materials, and audit and feedback. A cluster randomised controlled trial (cRCT) found the interventions to be effective in reducing use of five non-evidence based therapies in infants with bronchiolitis. This process evaluation paper aims to determine whether the interventions were implemented as planned (fidelity), explore end-users' perceptions of the interventions and evaluate cRCT outcome data with intervention fidelity data. METHODS: A pre-specified mixed-methods process evaluation was conducted alongside the cRCT, guided by frameworks for process evaluation of cRCTs and complex interventions. Quantitative data on the fidelity, dose and reach of interventions were collected from the 13 intervention hospitals during the study and analysed using descriptive statistics. Qualitative data identifying perception and acceptability of interventions were collected from 42 intervention hospital clinical leads on study completion and analysed using thematic analysis. RESULTS: The cRCT found targeted, theory-informed interventions improved bronchiolitis management by 14.1%. The process evaluation data found variability in how the intervention was delivered at the cluster and individual level. Total fidelity scores ranged from 55 to 98% across intervention hospitals (mean = 78%; SD = 13%). Fidelity scores were highest for use of clinical leads (mean = 98%; SD = 7%), and lowest for use of other educational materials (mean = 65%; SD = 19%) and audit and feedback (mean = 65%; SD = 20%). Clinical leads reflected positively about the interventions, with time constraints being the greatest barrier to their use. CONCLUSION: Our targeted, theory-informed interventions were delivered with moderate fidelity, and were well received by clinical leads. Despite clinical leads experiencing challenges of time constraints, the level of fidelity had a positive effect on successfully de-implementing non-evidence-based care in infants with bronchiolitis. These findings will inform widespread rollout of our bronchiolitis interventions, and guide future practice change in acute care settings. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry: ACTRN12616001567415 .

Myc linked to dysregulation of cholesterol transport and storage in nonsmall cell lung cancer.

Nonsmall cell lung cancer (NSCLC) is a leading cause of cancer-related deaths. While mutations in Kras and overexpression of Myc are commonly found in patients, the role of altered lipid metabolism in lung cancer and its interplay with oncogenic Myc is poorly understood. Here we use a transgenic mouse model of Kras-driven lung adenocarcinoma with reversible activation of Myc combined with surface analysis lipid profiling of lung tumors and transcriptomics to study the effect of Myc activity on cholesterol homeostasis. Our findings reveal that the activation of Myc leads to the accumulation of cholesteryl esters (CEs) stored in lipid droplets. Subsequent Myc deactivation leads to further increases in CEs, in contrast to tumors in which Myc was never activated. Gene expression analysis linked cholesterol transport and storage pathways to Myc activity. Our results suggest that increased Myc activity is associated with increased cholesterol influx, reduced efflux, and accumulation of CE-rich lipid droplets in lung tumors. Targeting cholesterol homeostasis is proposed as a promising avenue to explore for novel treatments of lung cancer, with diagnostic and stratification potential in human NSCLC.

Proteomic Analyses Identify a Novel Role for EZH2 in the Initiation of Cancer Cell Drug Tolerance.

Acquisition of drug resistance remains a chief impediment to successful cancer therapy, and we previously described a transient drug-tolerant cancer cell population (DTPs) whose survival is in part dependent on the activities of the histone methyltransferases G9a/EHMT2 and EZH2, the latter being the catalytic component of the polycomb repressive complex 2 (PRC2). Here, we apply multiple proteomic techniques to better understand the role of these histone methyltransferases (HMTs) in the establishment of the DTP state. Proteome-wide comparisons of lysine methylation patterns reveal that DTPs display an increase in methylation on K116 of PRC member Jarid2, an event that helps stabilize and recruit PRC2 to chromatin. We also find that EZH2, in addition to methylating histone H3K27, also can methylate G9a at K185, and that methylated G9a better recruits repressive complexes to chromatin. These complexes are similar to complexes recruited by histone H3 methylated at K9. Finally, a detailed histone post-translational modification (PTM) analysis shows that EZH2, either directly or through its ability to methylate G9a, alters H3K9 methylation in the context of H3 serine 10 phosphorylation, primarily in a cancer cell subpopulation that serves as DTP precursors. We also show that combinations of histone PTMs recruit a different set of complexes to chromatin, shedding light on the temporal mechanisms that contribute to drug tolerance.

Epigenetic factors Dnmt1 and Uhrf1 coordinate intestinal development.

Intestinal tract development is a coordinated process involving signaling among the progenitors and developing cells from all three germ layers. Development of endoderm-derived intestinal epithelium has been shown to depend on epigenetic modifications, but whether that is also the case for intestinal tract cell types from other germ layers remains unclear. We found that functional loss of a DNA methylation machinery component, ubiquitin-like protein containing PHD and RING finger domains 1 (uhrf1), leads to reduced numbers of ectoderm-derived enteric neurons and severe disruption of mesoderm-derived intestinal smooth muscle. Genetic chimeras revealed that Uhrf1 functions both cell-autonomously in enteric neuron precursors and cell-non-autonomously in surrounding intestinal cells, consistent with what is known about signaling interactions between these cell types that promote one another's development. Uhrf1 recruits the DNA methyltransferase Dnmt1 to unmethylated DNA during replication. Dnmt1 is also expressed in enteric neurons and smooth muscle progenitors. dnmt1 mutants have fewer enteric neurons and disrupted intestinal smooth muscle compared to wildtypes. Because dnmt1;uhrf1 double mutants have a similar phenotype to dnmt1 and uhrf1 single mutants, Dnmt1 and Uhrf1 must function together during enteric neuron and intestinal muscle development. This work shows that genes controlling epigenetic modifications are important to coordinate intestinal tract development, provides the first demonstration that these genes influence development of the ENS, and advances uhrf1 and dnmt1 as potential new Hirschsprung disease candidates.

Short- and long-term biological variation of cardiac troponin I in healthy individuals, and patients with end-stage renal failure requiring haemodialysis or cardiomyopathy.

Objectives High-sensitivity (hs) cardiac troponin (cTn) assays can quantitate small fluctuations in cTn concentration. Determining biological variation allows calculation of reference change values (RCV), to define significant changes. We assessed the short- and long-term biological variation of cardiac troponin I (cTnI) in healthy individuals and patients with renal failure requiring haemodialysis or cardiomyopathy. Methods Plasma samples were collected hourly for 4 h and weekly for seven further weeks from 20 healthy individuals, 9 renal failure patients and 20 cardiomyopathy patients. Pre- and post-haemodialysis samples were collected weekly for 7 weeks. Samples were analysed using a hs-cTnI assay (Abbott Alinity ci-series). Within-subject biological variation (CVI), analytical variation (CVA) and between-subject biological variation (CVG) was used to calculate RCVs and index of individuality (II). Results For healthy individuals, CVI, CVA, CVG, RCV and II values were 8.8, 14.0, 43.1, 45.8% and 0.38 respectively for short-term, and 41.4, 14.0, 25.8, 121.0% and 1.69 for long-term. For renal failure patients, these were 2.6, 5.8, 50.5, 17.6% and 0.30 respectively for short-term, and 19.1, 5.8, 11.2, 55.2% and 1.78 for long-term. For cardiomyopathy patients, these were 4.2, 10.0, 65.9, 30.0% and 0.16 respectively for short-term, and 17.5, 10.0, 63.1, 55.8% and 0.32 for long-term. Mean cTnI concentration was lower post-haemodialysis (15.2 vs. 17.8 ng/L, p < 0.0001), with a 16.9% mean relative change. Conclusions The biological variation of cTnI is similar between end-stage renal failure and cardiomyopathy patients, but proportionately greater in well-selected healthy individuals with very low baseline cTnI concentrations.

Understanding factors that contribute to variations in bronchiolitis management in acute care settings: a qualitative study in Australia and New Zealand using the Theoretical Domains Framework.

BACKGROUND: Bronchiolitis is the most common reason for infants under one year of age to be hospitalised. Despite management being well defined with high quality evidence of no efficacy for salbutamol, adrenaline, glucocorticoids, antibiotics or chest x-rays, substantial variation in practice occurs. Understanding factors that influence practice variation is vital in order to tailor knowledge translation interventions to improve practice. This study explores factors influencing the uptake of five evidence-based guideline recommendations using the Theoretical Domains Framework. METHODS: Semi-structured interviews were undertaken with clinicians in emergency departments and paediatric inpatient areas across Australia and New Zealand exploring current practice, and factors that influence this, based on the Theoretical Domains Framework. Interview transcripts were coded using thematic content analysis. RESULTS: Between July and October 2016, 20 clinicians (12 doctors, 8 nurses) were interviewed. Most clinicians believed chest x-rays were not indicated and caused radiation exposure (beliefs about consequences). However, in practice their decisions were influenced by concerns about misdiagnosis, severity of illness, lack of experience (knowledge) and confidence in managing infants with bronchiolitis (skills), and parental pressure influencing practice (social influences). Some senior clinicians believed trialling salbutamol might be of benefit for some infants (beliefs about consequences) but others strongly discounted this, believing salbutamol to be ineffective, with high quality evidence supporting this (knowledge). Most were concerned about antibiotic resistance and did not believe in antibiotic use in infants with bronchiolitis (beliefs about consequences) but experienced pressure from parents to prescribe (social influences). Glucocorticoid use was generally believed to be of no benefit (knowledge) with concerns surrounding frequency of use in primary care, and parental pressure (social influences). Nurse's reinforced evidence-based management of bronchiolitis with junior clinicians (social/professional role and identity). Regular turnover of medical staff, a lack of 'paediatric confident' nurses and doctors, reduced senior medical coverage after hours, and time pressure in emergency departments were factors influencing practice (environmental context and resources). CONCLUSIONS: Factors influencing the management of infants with bronchiolitis in the acute care period were identified using the Theoretical Domains Framework. These factors will inform the development of tailored knowledge translation interventions.