752 research outputs found

    The Chromospheric Activity and Ages of M Dwarf Stars in Wide Binary Systems

    Get PDF
    We investigate the relationship between age and chromospheric activity for 139 M dwarf stars in wide binary systems with white dwarf companions. The age of each system is determined from the cooling age of its white dwarf component. The current limit for activity-age relations found for M dwarfs in open clusters is 4 Gyr. Our unique approach to finding ages for M stars allows for the exploration of this relationship at ages older than 4 Gyr. The general trend of stars remaining active for a longer time at later spectral type is confirmed. However, our larger sample and greater age range reveals additional complexity in assigning age based on activity alone. We find that M dwarfs in wide binaries older than 4 Gyr depart from the log-linear relation for clusters and are found to have activity at magnitudes, colors and masses which are brighter, bluer and more massive than predicted by the cluster relation. In addition to our activity-age results, we present the measured radial velocities and complete space motions for 161 white dwarf stars in wide binaries.Comment: 22 pages including 9 figures and 5 tables. Accepted for publication in The Astronomical Journa

    Children\u27s Sleep during COVID-19: How Sleep Influences Surviving and Thriving in Families

    Get PDF
    Objective The COVID-19 pandemic has the potential to disrupt the lives of families and may have implications for children with existing sleep problems. As such, we aimed to: (1) characterize sleep changes during the COVID-19 pandemic in children who had previously been identified as having sleep problems, (2) identify factors contributing to sleep changes due to COVID-19 safety measures, and (3) understand parents and children s needs to support sleep during the pandemic. Methods Eighty-five Canadian parents with children aged 4 14 years participated in this explanatory sequential, mixed-methods study using an online survey of children s and parents sleep, with a subset of 16 parents, selected based on changes in their children s sleep, participating in semi-structured interviews. Families had previously participated in the Better Nights, Better Days (BNBD) randomized controlled trial. Results While some parents perceived their child s sleep quality improved during the COVID-19 pandemic (14.1%, n 12), many parents perceived their child s sleep had worsened (40.0%, n 34). Parents attributed children s worsened sleep to increased screen time, anxiety, and decreased exercise. Findings from semi-structured interviews highlighted the effect of disrupted routines on sleep and stress, and that stress reciprocally influenced children s and parents sleep. Conclusions The sleep of many Canadian children was affected by the first wave of the COVID-19 pandemic, with the disruption of routines influencing children s sleep. eHealth interventions, such as BNBD with modifications that address the COVID-19 context, could help families address these challenges

    Survival Data and Predictors of Functional Outcome an Average of 15 Years after the Fontan Procedure: The Pediatric Heart Network Fontan Cohort

    Full text link
    ObjectiveMulticenter longitudinal outcome data for Fontan patients surviving into adulthood are lacking. The aim of this study was to better understand contemporary outcomes in Fontan survivors by collecting follow‐up data in a previously well‐characterized cohort.DesignBaseline data from the Fontan Cross‐Sectional Study (Fontan 1) were previously obtained in 546 Fontan survivors aged 11.9 ± 3.4 years. We assessed current transplant‐free survival status in all subjects 6.8 ± 0.4 years after the Fontan 1 study. Anatomic, clinical, and surgical data were collected along with socioeconomic status and access to health care.ResultsThirty subjects (5%) died or underwent transplantation since Fontan 1. Subjects with both an elevated (>21 pg/mL) brain natriuretic peptide and a low Child Health Questionnaire physical summary score (<44) measured at Fontan 1 were significantly more likely to die or undergo transplant than the remainder, with a hazard ratio of 6.2 (2.9–13.5). Among 516 Fontan survivors, 427 (83%) enrolled in this follow‐up study (Fontan 2) at 18.4 ± 3.4 years of age. Although mean scores on functional health status questionnaires were lower than the general population, individual scores were within the normal range in 78% and 88% of subjects for the Child Health Questionnaire physical and psychosocial summary score, and 97% and 91% for the SF‐36 physical and mental aggregate score, respectively. Since Fontan surgery, 119 (28%) had additional cardiac surgery; 55% of these (n = 66) in the interim between Fontan 1 and Fontan 2. A catheter intervention occurred in 242 (57%); 32% of these (n = 78) after Fontan 1. Arrhythmia requiring treatment developed in 118 (28%) after Fontan surgery; 58% of these (n = 68) since Fontan 1.ConclusionsWe found 95% interim transplant‐free survival for Fontan survivors over an average of 7 years of follow‐up. Continued longitudinal investigation into adulthood is necessary to better understand the determinants of long‐term outcomes and to improve functional health status.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110738/1/chd12193.pd

    Interleukin-15 Treatment Induces Weight Loss Independent of Lymphocytes

    Get PDF
    Obesity is a chronic inflammatory condition characterized by activation and infiltration of proinflammatory immune cells and a dysregulated production of proinflammatory cytokines. While known as a key regulator of immune natural killer (NK) cell function and development, we have recently demonstrated that reduced expression of the cytokine Interleukin-15 (IL-15) is closely linked with increased body weight and adiposity in mice and humans. Previously, we and others have shown that obese individuals have lower circulating levels of IL-15 and NK cells. Lean IL-15 overexpressing (IL-15 tg) mice had an accumulation in adipose NK cells compared to wildtype and NK cell deficient obese IL-15−/− mice. Since IL-15 induces weight loss in IL-15−/− and diet induced obese mice and has effects on various lymphocytes, the aim of this paper was to determine if lymphocytes, particularly NK cells, play a role in IL-15 mediated weight loss. Acute IL-15 treatment resulted in an increased accumulation of NK, NKT, and CD3+ T cells in adipose tissue of B6 mice. Mice depleted of NK and NKT cells had similar weight loss comparable to controls treated with IL-15. Finally, IL-15 treatment induces significant weight loss in lymphocyte deficient RAG2−/−γc−/− mice independent of food intake. Fat pad cross-sections show decreased pad size with cytokine treatment is due to adipocyte shrinkage. These results clearly suggest that IL-15 mediates weight loss independent of lymphocytes

    Burnout and use of HIV services among health care workers in Lusaka District, Zambia: a cross-sectional study

    Get PDF
    BACKGROUND: Well-documented shortages of health care workers in sub-Saharan Africa are exacerbated by the increased human resource demands of rapidly expanding HIV care and treatment programmes. The successful continuation of existing programmes is threatened by health care worker burnout and HIV-related illness. METHODS: From March to June 2007, we studied occupational burnout and utilization of HIV services among health providers in the Lusaka public health sector. Providers from 13 public clinics were given a 36-item, self-administered questionnaire and invited for focus group discussions and key-informant interviews. RESULTS: Some 483 active clinical staff completed the questionnaire (84% response rate), 50 staff participated in six focus groups, and four individuals gave interviews. Focus group participants described burnout as feeling overworked, stressed and tired. In the survey, 51% reported occupational burnout. Risk factors were having another job (RR 1.4 95% CI 1.2-1.6) and knowing a co-worker who left in the last year (RR 1.6 95% CI 1.3-2.2). Reasons for co-worker attrition included: better pay (40%), feeling overworked or stressed (21%), moving away (16%), death (8%) and illness (5%). When asked about HIV testing, 370 of 456 (81%) reported having tested; 240 (50%) tested in the last year. In contrast, discussion groups perceived low testing rates. Both discussion groups and survey respondents identified confidentiality as the prime reason for not undergoing HIV testing. CONCLUSION: In Lusaka primary care clinics, overwork, illness and death were common reasons for attrition. Programmes to improve access, acceptability and confidentiality of health care services for clinical providers and to reduce workplace stress could substantially affect workforce stability

    A clinically relevant sheep model of orthotopic heart transplantation 24 h after donor brainstem death

    Get PDF
    BACKGROUND: Heart transplantation (HTx) from brainstem dead (BSD) donors is the gold-standard therapy for severe/end-stage cardiac disease, but is limited by a global donor heart shortage. Consequently, innovative solutions to increase donor heart availability and utilisation are rapidly expanding. Clinically relevant preclinical models are essential for evaluating interventions for human translation, yet few exist that accurately mimic all key HTx components, incorporating injuries beginning in the donor, through to the recipient. To enable future assessment of novel perfusion technologies in our research program, we thus aimed to develop a clinically relevant sheep model of HTx following 24 h of donor BSD. METHODS: BSD donors (vs. sham neurological injury, 4/group) were hemodynamically supported and monitored for 24 h, followed by heart preservation with cold static storage. Bicaval orthotopic HTx was performed in matched recipients, who were weaned from cardiopulmonary bypass (CPB), and monitored for 6 h. Donor and recipient blood were assayed for inflammatory and cardiac injury markers, and cardiac function was assessed using echocardiography. Repeated measurements between the two different groups during the study observation period were assessed by mixed ANOVA for repeated measures. RESULTS: Brainstem death caused an immediate catecholaminergic hemodynamic response (mean arterial pressure, p = 0.09), systemic inflammation (IL-6 - p = 0.025, IL-8 - p = 0.002) and cardiac injury (cardiac troponin I, p = 0.048), requiring vasopressor support (vasopressor dependency index, VDI, p = 0.023), with normalisation of biomarkers and physiology over 24 h. All hearts were weaned from CPB and monitored for 6 h post-HTx, except one (sham) recipient that died 2 h post-HTx. Hemodynamic (VDI - p = 0.592, heart rate - p = 0.747) and metabolic (blood lactate, p = 0.546) parameters post-HTx were comparable between groups, despite the observed physiological perturbations that occurred during donor BSD. All p values denote interaction among groups and time in the ANOVA for repeated measures. CONCLUSIONS: We have successfully developed an ovine HTx model following 24 h of donor BSD. After 6 h of critical care management post-HTx, there were no differences between groups, despite evident hemodynamic perturbations, systemic inflammation, and cardiac injury observed during donor BSD. This preclinical model provides a platform for critical assessment of injury development pre- and post-HTx, and novel therapeutic evaluation. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40635-021-00425-4

    A molecular basis for the association of the HLA-DRB1 locus, citrullination, and rheumatoid arthritis

    Get PDF
    Rheumatoid arthritis (RA) is strongly associated with the human leukocyte antigen (HLA)- DRB1 locus that possesses the shared susceptibility epitope (SE) and the citrullination of self-antigens. We show how citrullinated aggrecan and vimentin epitopes bind to HLADRB1* 04:01/04. Citrulline was accommodated within the electropositive P4 pocket of HLA-DRB1*04:01/04, whereas the electronegative P4 pocket of the RA-resistant HLADRB1* 04:02 allomorph interacted with arginine or citrulline-containing epitopes. Peptide elution studies revealed P4 arginine-containing peptides from HLA-DRB1*04:02, but not from HLA-DRB1*04:01/04. Citrullination altered protease susceptibility of vimentin, thereby generating self-epitopes that are presented to T cells in HLA-DRB1*04:01+ individuals. Using HLA-II tetramers, we observed citrullinated vimentin- and aggrecan-specific CD4+ T cells in the peripheral blood of HLA-DRB1*04:01+ RA-affected and healthy individuals. In RA patients, autoreactive T cell numbers correlated with disease activity and were deficient in regulatory T cells relative to healthy individuals. These findings reshape our understanding of the association between citrullination, the HLA-DRB1 locus, and T cell autoreactivity in RA

    Core Outcomes Set for Trials in People With Coronavirus Disease 2019.

    Get PDF
    OBJECTIVES: The outcomes reported in trials in coronavirus disease 2019 are extremely heterogeneous and of uncertain patient relevance, limiting their applicability for clinical decision-making. The aim of this workshop was to establish a core outcomes set for trials in people with suspected or confirmed coronavirus disease 2019. DESIGN: Four international online multistakeholder consensus workshops were convened to discuss proposed core outcomes for trials in people with suspected or confirmed coronavirus disease 2019, informed by a survey involving 9,289 respondents from 111 countries. The transcripts were analyzed thematically. The workshop recommendations were used to finalize the core outcomes set. SETTING: International. SUBJECTS: Adults 18 years old and over with confirmed or suspected coronavirus disease 2019, their family members, members of the general public and health professionals (including clinicians, policy makers, regulators, funders, researchers). INTERVENTIONS: None. MEASUREMENTS: None. MAIN RESULTS: Six themes were identified. "Responding to the critical and acute health crisis" reflected the immediate focus on saving lives and preventing life-threatening complications that underpinned the high prioritization of mortality, respiratory failure, and multiple organ failure. "Capturing different settings of care" highlighted the need to minimize the burden on hospitals and to acknowledge outcomes in community settings. "Encompassing the full trajectory and severity of disease" was addressing longer term impacts and the full spectrum of illness (e.g. shortness of breath and recovery). "Distinguishing overlap, correlation and collinearity" meant recognizing that symptoms such as shortness of breath had distinct value and minimizing overlap (e.g. lung function and pneumonia were on the continuum toward respiratory failure). "Recognizing adverse events" refers to the potential harms of new and evolving interventions. "Being cognizant of family and psychosocial wellbeing" reflected the pervasive impacts of coronavirus disease 2019. CONCLUSIONS: Mortality, respiratory failure, multiple organ failure, shortness of breath, and recovery are critically important outcomes to be consistently reported in coronavirus disease 2019 trials
    corecore