1,267 research outputs found

    Phylogenomic Analysis Reveals Dynamic Evolutionary History of the Drosophila Heterochromatin Protein 1 (HP1) Gene Family

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    Heterochromatin is the gene-poor, satellite-rich eukaryotic genome compartment that supports many essential cellular processes. The functional diversity of proteins that bind and often epigenetically define heterochromatic DNA sequence reflects the diverse functions supported by this enigmatic genome compartment. Moreover, heterogeneous signatures of selection at chromosomal proteins often mirror the heterogeneity of evolutionary forces that act on heterochromatic DNA. To identify new such surrogates for dissecting heterochromatin function and evolution, we conducted a comprehensive phylogenomic analysis of the Heterochromatin Protein 1 gene family across 40 million years of Drosophila evolution. Our study expands this gene family from 5 genes to at least 26 genes, including several uncharacterized genes in Drosophila melanogaster. The 21 newly defined HP1s introduce unprecedented structural diversity, lineage-restriction, and germline-biased expression patterns into the HP1 family. We find little evidence of positive selection at these HP1 genes in both population genetic and molecular evolution analyses. Instead, we find that dynamic evolution occurs via prolific gene gains and losses. Despite this dynamic gene turnover, the number of HP1 genes is relatively constant across species. We propose that karyotype evolution drives at least some HP1 gene turnover. For example, the loss of the male germline-restricted HP1E in the obscura group coincides with one episode of dramatic karyotypic evolution, including the gain of a neo-Y in this lineage. This expanded compendium of ovary- and testis-restricted HP1 genes revealed by our study, together with correlated gain/loss dynamics and chromosome fission/fusion events, will guide functional analyses of novel roles supported by germline chromatin

    Determinants of Heart Failure Self-Care Maintenance and Management in Patients and Caregivers: A Dyadic Analysis

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    Disease self-management is a critical component of maintaining clinical stability for patients with chronic illness. This is particularly evident in the context of heart failure (HF), which is the leading cause of hospitalization for older adults. HF self-management, commonly known as HF self-care, is often performed with the support of informal caregivers. However, little is known about how a HF dyad manages the patient\u27s care together. The purpose of this study was to identify determinants of patient and caregiver contributions to HF self-care maintenance (daily adherence and symptom monitoring) and management (appropriate recognition and response to symptoms), utilizing an approach that controls for dyadic interdependence. This was a secondary analysis of cross-sectional data from 364 dyads of Italian HF patients and caregivers. Multilevel modeling was used to identify determinants of HF self-care within patient-caregiver dyads. Patients averaged 76.2 (SD = 10.7) years old, and a slight majority (56.9%) was male, whereas caregivers averaged 57.4 (SD = 14.6) years old, and about half (48.1%) were male. Most caregivers were adult children (48.4%) or spouses (32.7%) of patients. Both patients and caregivers reported low levels of HF maintenance and management behaviors. Significant individual and dyadic determinants of self-care maintenance and self-care management included gender, quality of life, comorbid burden, impaired ADLs, cognition, hospitalizations, HF duration, relationship type, relationship quality, and social support. These comprehensive dyadic models assist in elucidating the complex nature of patient-caregiver relationships and their influence on HF self-care, leading to more effective ways to intervene and optimize outcomes

    A Dyadic Approach to Managing Heart Failure with Confidence

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    Background: The majority of heart failure (HF) self-care research remains focused on patients, despite the important involvement of family caregivers. Although self-care confidence has been found to play an important role in the effectiveness of HF self-care management on patient outcomes, no known research has examined self-care confidence within a dyadic context. Objective: The purpose of this study was to identify individual and dyadic determinants of self-care confidence in HF care dyads. Methods: Multilevel modeling, which controls for the interdependent nature of dyadic data, was used to examine 329 Italian HF dyads (caregivers were either spouses or adult children). Results: Both patients and caregivers reported lower-than-adequate levels of confidence, with caregivers reporting slightly higher confidence than patients. Patient and caregiver levels of confidence were significantly associated with greater patient-reported relationship quality and better caregiver mental health. Patient confidence in self-care was significantly associated with patient female gender, nonspousal care dyads, poor caregiver physical health, and low care strain. Caregiver confidence to contribute to self-care was significantly associated with poor emotional quality of life in patients and greater perceived social support by caregivers. Conclusions: Findings are supportive of the need for a dyadic perspective of HF self-care in practice and research as well as the importance of addressing the needs of both members of the dyad to maximize optimal outcomes for both

    Epidemiology of Non-small Cell Lung Cancer in Asian Americans: Incidence Patterns Among Six Subgroups by Nativity

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    BackgroundDifferences in the epidemiology of lung cancer between Asians and non-Hispanic whites have brought to light the relative influences of genetic and environmental factors on lung cancer risk. We set out to describe the epidemiology of non-small cell lung cancer (NSCLC) among Asians living in California, and to explore the effects of acculturation on lung cancer risk by comparing lung cancer rates between U.S.-born and foreign-born Asians.MethodsAge-adjusted incidence rates of NSCLC were calculated for Chinese, Filipino, Japanese, Korean, Vietnamese, and South Asians in California between 1988 and 2003 using data from the California Cancer Registry. Incidence rates were calculated and stratified by sex and nativity. We analyzed population-based tobacco smoking prevalence data to determine whether differences in rates were associated with prevalence of tobacco smoking.ResultsAsians have overall lower incidence rates of NSCLC compared with whites (29.8 and 57.7 per 100,000, respectively). South Asians have markedly low rates of NSCLC (12.0 per 100,000). Foreign-born Asian men and women have an approximately 35% higher rate of NSCLC than U.S.-born Asian men and women. The incidence pattern by nativity is consistent with the population prevalence of smoking among Asian men; however, among women, the prevalence of smoking is higher among U.S.-born, which is counter to their incidence patterns.ConclusionsForeign-born Asians have a higher rate of NSCLC than U.S.-born Asians, which may be due to environmental tobacco smoke or nontobacco exposures among women. South Asians have a remarkably low rate of NSCLC that approaches white levels among the U.S.-born. More studies with individual-level survey data are needed to identify the specific environmental factors associated with differential lung cancer risk occurring with acculturation among Asians

    Scoring tools to identify TB patients facing catastrophic costs in the Philippines.

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    BACKGROUND: This study was to meet a practical need to design a simple tool to identify TB patients who may potentially be facing catastrophic costs while seeking TB care in the public sector. Such a tool may help prevent and address catastrophic costs among individual patients. METHODS: We used data from the national TB patient cost survey in the Philippines. We randomly allocated TB patients to either the derivation or validation sample. Using adjusted odds ratios (ORs) and β coefficients of logistic regression, we developed four scoring systems to identify TB patients who may be facing catastrophic costs from the derivation sample. We validated each scoring system in the validation sample. RESULTS: We identified a total of 12 factors as predictive indicators associated with catastrophic costs. Using all 12 factors, the β coefficients-based scoring system (area under the curve [AUC] 0.783, 95% CI 0.754-0.812) had a high validity. Even with seven selected factors with OR > 2.0, the validity remained in the acceptable range (β coefficients-based: AUC 0.767, 95% CI 0.737-0.798). CONCLUSION: The β coefficients-based scoring systems in this analysis can be used to identify those at high risk of facing catastrophic costs due to TB in the Philippines. Operational feasibility needs to be investigated further to implement this in routine TB surveillance

    Comparison of Two Mathematical Models for Greenhouse Gas Emission from Membrane Bioreactors

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    In this study two mathematical models (Model I and Model II), able to predict the nitrous oxide (N2O) and carbon dioxide (CO2) emission from an University Cape Town (UCT) \u2013 membrane bioreactor (MBR) plant, have been compared. Model I considers the N2O production only during the denitrification. Model II takes into account the two ammonia-oxidizing bacteria (AOB) formation pathways for N2O. Both models were calibrated adopting real data. Results highlight that Model II had a better capability of reproducing the measured data especially in terms of N2O model outputs. Indeed, the average efficiency related to the N2O model outputs was equal to 0.3 and 0.38 for Model I and Model II respectively

    Application of adaptive design and decision making to a phase II trial of a phosphodiesterase inhibitor for the treatment of intermittent claudication

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    Background: Claudication secondary to peripheral artery disease (PAD) is associated with substantial functional impairment. Phosphodiesterase (PDE) inhibitors have been shown to increase walking performance in these patients. K-134 is a selective PDE 3 inhibitor being developed as a potential treatment for claudication. The use of K-134, as with other PDE 3 inhibitors, in patients with PAD raises important safety and tolerability concerns, including the induction of cardiac ischemia, tachycardia, and hypotension. We describe the design, oversight, and implementation of an adaptive, phase II, dose-finding trial evaluating K-134 for the treatment of stable, intermittent claudication. Methods: The study design was a double-blind, multi-dose (25 mg, 50 mg, and 100 mg of K-134), randomized trial with both placebo and active comparator arms conducted in the United States and Russia. The primary objective of the study was to compare the highest tolerable dose of K-134 versus placebo using peak walking time after 26 weeks of therapy as the primary outcome. Study visits with intensive safety assessments were included early in the study period to provide data for adaptive decision making. The trial used an adaptive, dose-finding strategy to efficiently identify the highest dose(s) most likely to be safe and well tolerated, based on the side effect profiles observed within the trial, so that less promising doses could be abandoned. Protocol specified criteria for safety and tolerability endpoints were used and modeled prior to the adaptive decision making. The maximum target sample size was 85 subjects in each of the retained treatment arms. Results: When 199 subjects had been randomized and 28-day data were available from 143, the Data Monitoring Committee (DMC) recommended termination of the lowest dose (25 mg) treatment arm. Safety evaluations performed during 14- and 28-day visits which included in-clinic dosing and assessments at peak drug concentrations provided core data for the DMC review. At the time of review, no subject in any of the five treatment arms (placebo, three K-134-containing arms, and cilostazol) had met pre-specified definitions for resting tachycardia or ischemic changes on exercise ECG. If, instead of dropping the 25-mg K-134 treatment arm, all arms had been continued to full enrollment, then approximately 43 additional research subjects would have been required to complete the trial. Conclusions: In this phase II, dose-finding trial of K-134 in the treatment of stable intermittent claudication, no concerning safety signals were seen at interim analysis, allowing the discontinuation of the lowest-dose-containing arm and the retention of the two highest-dose-containing arms. The adaptive design facilitated safe and efficient evaluation of K-134 in this high-risk cardiovascular population

    Multicenter randomized controlled trial on Duration of Therapy for Thrombosis in Children and Young Adults (the Kids-DOTT trial): pilot/feasibility phase findings

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    BACKGROUND: Randomized controlled trials (RCTs) on pediatric venous thromboembolism (VTE) treatment have been challenged by unsubstantiated design assumptions and/or poor accrual. Pilot/feasibility (P/F) studies are critical to future RCT success. METHODS: The Kids-DOTT trial is a multicenter RCT investigating non-inferiority of a 6-week (shortened) versus 3-month (conventional) duration of anticoagulation in patients aged \u3c 21 years with provoked venous thrombosis. Primary efficacy and safety endpoints are symptomatic recurrent VTE at 1 year and anticoagulant-related, clinically relevant bleeding. In the P/F phase, 100 participants were enrolled in an open, blinded-endpoint, parallel-cohort RCT design. RESULTS: No eligibility violations or randomization errors occurred. Of the enrolled patients, 69% were randomized, 3% missed the randomization window, and 28% were followed in prespecified observational cohorts for completely occlusive thrombosis or persistent antiphospholipid antibodies. Retention at 1 year was 82%. Interobserver agreement between local and blinded central determination of venous occlusion by imaging at 6 weeks after diagnosis was strong (k-statistic = 0.75; 95% confidence interval [CI] 0.48-1.0). The primary efficacy and safety event rates were 3.3% (95% CI 0.3-11.5%) and 1.4% (95% CI 0.03-7.4%). CONCLUSIONS: The P/F phase of the Kids-DOTT trial has demonstrated the validity of vascular imaging findings of occlusion as a randomization criterion, and defined randomization, retention and endpoint rates to inform the fully powered RCT

    Surgical revascularization versus amputation for peripheral vascular disease in dialysis patients: a cohort study

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    BACKGROUND: Surgical treatment of peripheral vascular disease (PVD) in dialysis patients is controversial. METHODS: We examined the post-operative morbidity and mortality of surgical revascularization or amputation for PVD in a retrospective analysis of United States Renal Data System. Propensity scores for undergoing amputation were derived from a multivariable logistic regression model of amputation. RESULTS: Of the Medicare patients initiated on dialysis from Jan 1, 1995 to Dec 31, 1999, patients underwent surgical revascularization (n = 1,896) or amputation (n = 2,046) in the first 6 months following initiation of dialysis were studied. In the logistic regression model, compared to claudication, presence of gangrene had a strong association with amputation [odds ratio (OR) 19.0, 95% CI (confidence interval) 13.86–25.95]. The odds of dying within 30 days and within1 year were higher (30 day OR: 1.85, 95% CI: 1.45–2.36; 1 yr OR: 1.46, 95% CI: 1.25–1.71) in the amputation group in logistic regression model adjusted for propensity scores and other baseline factors. Amputation was associated with increased odds of death in patients with low likelihood of amputation (< 33(rd )percentile of propensity score) and moderate likelihood of amputation (33(rd )to 66(th )percentile) but not in high likelihood group (>66(th )percentile). The number of hospital days in the amputation and revascularization groups was not different. CONCLUSION: Amputation might be associated with higher mortality in dialysis patients. Where feasible, revascularization might be preferable over amputation in dialysis patients

    Prescription dose evaluation for APBI with noninvasive image-guided breast brachytherapy using equivalent uniform dose

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    ABSTRACT PURPOSE: Noninvasive image-guided breast brachytherapy (NIBB) is an attractive novel approach to deliver accelerated partial breast irradiation (APBI). Calculations of equivalent uniform dose (EUD) were performed to identify the appropriate APBI dose for this technique. METHODS AND MATERIALS: APBI plans were developed for 15 patients: five with threedimensional conformal APBI (3D-CRT), five with multi-lumen intracavitary balloons (m-IBB), and five simulating NIBB treatment. Prescription doses of 34.0 and 38.5 Gy were delivered in 10 fractions for m-IBB and 3D-CRT, respectively. Prescription doses ranging from 34.0 to 38.5 Gy were considered for NIBB. Dose-volume histogram data from all 3D-CRT, m-IBB, and NIBB plans were used to calculate the biologically effective EUD and corresponding EUD to the PTV_eval using the following equation: ). An a/b value of 4.6 Gy was assumed for breast tumor. EUD for varying NIBB prescription doses were compared with EUD values for the other APBI techniques. RESULTS: Mean PTV_eval volume was largest for 3D-CRT (372.9 cm 3 ) and was similar for NIBB and m-IBB (88.7 and 87.2 cm 3 , respectively). The EUD value obtained by prescribing 38.5 Gy with 3D-CRT APBI was 38.6 Gy. The EUD value of 34.0 Gy prescribed with m-IBB was 34.4 Gy. EUD values for NIBB ranged from 33.9 to 38.2 Gy for prescription doses ranging from 34.0 to 38.5 Gy. CONCLUSIONS: Using EUD calculations to compare APBI techniques and treatment doses, a prescription dose of 36.0 Gy in 10 fractions using NIBB has a comparable biologic equivalent dose to other established brachytherapy techniques.
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