500 research outputs found

    Adiposity has differing associations with incident coronary heart disease and mortality in the Scottish population: cross-sectional surveys with follow-up

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    Objective: Investigation of the association of excess adiposity with three different outcomes: all-cause mortality, coronary heart disease (CHD) mortality and incident CHD. Design: Cross-sectional surveys linked to hospital admissions and death records. Subjects: 19 329 adults (aged 18–86 years) from a representative sample of the Scottish population. Measurements: Gender-stratified Cox proportional hazards models were used to estimate hazard ratios (HRs) for all-cause mortality, CHD mortality and incident CHD. Separate models incorporating the anthropometric measurements body mass index (BMI), waist circumference (WC) or waist–hip ratio (WHR) were created adjusted for age, year of survey, smoking status and alcohol consumption. Results: For both genders, BMI-defined obesity (greater than or equal to30 kg m−2) was not associated with either an increased risk of all-cause mortality or CHD mortality. However, there was an increased risk of incident CHD among the obese men (hazard ratio (HR)=1.78; 95% confidence interval=1.37–2.31) and obese women (HR=1.93; 95% confidence interval=1.44–2.59). There was a similar pattern for WC with regard to the three outcomes; for incident CHD, the HR=1.70 (1.35–2.14) for men and 1.71 (1.28–2.29) for women in the highest WC category (men greater than or equal to102 cm, women greater than or equal to88 cm), synonymous with abdominal obesity. For men, the highest category of WHR (greater than or equal to1.0) was associated with an increased risk of all-cause mortality (1.29; 1.04–1.60) and incident CHD (1.55; 1.19–2.01). Among women with a high WHR (greater than or equal to0.85) there was an increased risk of all outcomes: all-cause mortality (1.56; 1.26–1.94), CHD mortality (2.49; 1.36–4.56) and incident CHD (1.76; 1.31–2.38). Conclusions: In this study excess adiposity was associated with an increased risk of incident CHD but not necessarily death. One possibility is that modern medical intervention has contributed to improved survival of first CHD events. The future health burden of increased obesity levels may manifest as an increase in the prevalence of individuals living with CHD and its consequences

    X-ray-selected broad absorption line quasi-stellar objects

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    We study a sample of six X-ray-selected broad absorption line (BAL) quasi-stellar objects (QSOs) from the XMM–Newton Wide Angle Survey. All six objects are classified as BALQSOs using the classic balnicity index, and together they form the largest sample of X-ray-selected BALQSOs. We find evidence for absorption in the X-ray spectra of all six objects. An ionized absorption model applied to an X-ray spectral shape that would be typical for non-BAL QSOs (a power law with energy index α = 0.98) provides acceptable fits to the X-ray spectra of all six objects. The optical to X-ray spectral indices, αOX, of the X-ray-selected BALQSOs, have a mean value of ă€ˆÎ±OX〉 = 1.69 ± 0.05, which is similar to that found for X-ray-selected and optically selected non-BAL QSOs of a similar ultraviolet luminosity. In contrast, optically selected BALQSOs typically have much larger αOX and so are characterized as being X-ray weak. The results imply that X-ray selection yields intrinsically X-ray bright BALQSOs, but their X-ray spectra are absorbed by a similar degree to that seen in optically selected BALQSO samples; X-ray absorption appears to be ubiquitous in BALQSOs, but X-ray weakness is not. We argue that BALQSOs sit at one end of a spectrum of X-ray absorption properties in QSOs related to the degree of ultraviolet absorption in C iv 1550 Å

    Utility of a thematic network in primary health care: a controlled interventional study in a rural area

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    BACKGROUND: UniNet is an Internet-based thematic network for a virtual community of users (VCU). It supports a virtual multidisciplinary community for physicians, focused on the improvement of clinical practice. This is a study of the effects of a thematic network such as UniNet on primary care medicine in a rural area, specifically as a platform of communication between specialists at the hospital and doctors in the rural area. METHODS: In order to study the effects of a thematic network such as UniNet on primary care medicine in a rural area, we designed an interventional study that included a control group. The measurements included the number of patient displacements due to disease, number of patient hospital stays and the number of prescriptions of drugs of low therapeutic utility and generic drug prescriptions by doctors. These data were analysed and compared with those of the control center. RESULTS: Our study showed positive changes in medical practice, reflected in the improvement of the evaluated parameters in the rural health area where the interventional study was carried out, compared with the control area. We discuss the strengths and weaknesses of UniNet as a potential medium to improve the quality of medical care in rural areas. CONCLUSION: The rural doctors had an effective, useful, user-friendly and cheap source of medical information that may have contributed to the improvement observed in the medical quality indices

    Evaluating the Quality of Research into a Single Prognostic Biomarker: A Systematic Review and Meta-analysis of 83 Studies of C-Reactive Protein in Stable Coronary Artery Disease

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    Background Systematic evaluations of the quality of research on a single prognostic biomarker are rare. We sought to evaluate the quality of prognostic research evidence for the association of C-reactive protein (CRP) with fatal and nonfatal events among patients with stable coronary disease. Methods and Findings We searched MEDLINE (1966 to 2009) and EMBASE (1980 to 2009) and selected prospective studies of patients with stable coronary disease, reporting a relative risk for the association of CRP with death and nonfatal cardiovascular events. We included 83 studies, reporting 61,684 patients and 6,485 outcome events. No study reported a prespecified statistical analysis protocol; only two studies reported the time elapsed (in months or years) between initial presentation of symptomatic coronary disease and inclusion in the study. Studies reported a median of seven items (of 17) from the REMARK reporting guidelines, with no evidence of change over time. The pooled relative risk for the top versus bottom third of CRP distribution was 1.97 (95% confidence interval [CI] 1.78–2.17), with substantial heterogeneity (I2 = 79.5). Only 13 studies adjusted for conventional risk factors (age, sex, smoking, obesity, diabetes, and low-density lipoprotein [LDL] cholesterol) and these had a relative risk of 1.65 (95% CI 1.39–1.96), I2 = 33.7. Studies reported ten different ways of comparing CRP values, with weaker relative risks for those based on continuous measures. Adjusting for publication bias (for which there was strong evidence, Egger's p<0.001) using a validated method reduced the relative risk to 1.19 (95% CI 1.13–1.25). Only two studies reported a measure of discrimination (c-statistic). In 20 studies the detection rate for subsequent events could be calculated and was 31% for a 10% false positive rate, and the calculated pooled c-statistic was 0.61 (0.57–0.66). Conclusion Multiple types of reporting bias, and publication bias, make the magnitude of any independent association between CRP and prognosis among patients with stable coronary disease sufficiently uncertain that no clinical practice recommendations can be made. Publication of prespecified statistical analytic protocols and prospective registration of studies, among other measures, might help improve the quality of prognostic biomarker research

    Sabotage in Contests: A Survey

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    A contest is a situation in which individuals expend irretrievable resources to win valuable prize(s). ‘Sabotage’ is a deliberate and costly act of damaging a rival’s' likelihood of winning the contest. Sabotage can be observed in, e.g., sports, war, promotion tournaments, political or marketing campaigns. In this article, we provide a model and various perspectives on such sabotage activities and review the economics literature analyzing the act of sabotage in contests. We discuss the theories and evidence highlighting the means of sabotage, why sabotage occurs, and the effects of sabotage on individual players and on overall welfare, along with possible mechanisms to reduce sabotage. We note that most sabotage activities are aimed at the ablest player, the possibility of sabotage reduces productive effort exerted by the players, and sabotage may lessen the effectiveness of public policies, such as affirmative action, or information revelation in contests. We discuss various policies that a designer may employ to counteract sabotage activities. We conclude by pointing out some areas of future research

    Coordination of Cell Differentiation and Migration in Mathematical Models of Caudal Embryonic Axis Extension

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    Vertebrate embryos display a predominant head-to-tail body axis whose formation is associated with the progressive development of post-cranial structures from a pool of caudal undifferentiated cells. This involves the maintenance of active FGF signaling in this caudal region as a consequence of the restricted production of the secreted factor FGF8. FGF8 is transcribed specifically in the caudal precursor region and is down-regulated as cells differentiate and the embryo extends caudally. We are interested in understanding the progressive down-regulation of FGF8 and its coordination with the caudal movement of cells which is also known to be FGF-signaling dependent. Our study is performed using mathematical modeling and computer simulations. We use an individual-based hybrid model as well as a caricature continuous model for the simulation of experimental observations (ours and those known from the literature) in order to examine possible mechanisms that drive differentiation and cell movement during the axis elongation. Using these models we have identified a possible gene regulatory network involving self-repression of a caudal morphogen coupled to directional domain movement that may account for progressive down-regulation of FGF8 and conservation of the FGF8 domain of expression. Furthermore, we have shown that chemotaxis driven by molecules, such as FGF8 secreted in the stem zone, could underlie the migration of the caudal precursor zone and, therefore, embryonic axis extension. These mechanisms may also be at play in other developmental processes displaying a similar mode of axis extension coupled to cell differentiation

    Orlistat after initial dietary/behavioural treatment: changes in body weight and dietary maintenance in subjects with sleep related breathing disorders

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    <p>Abstract</p> <p>Background</p> <p>Sleep related breathing disorders (SRBD) are associated with increased morbidity and mortality and weight loss is recommended to overweight or obese patients with SRBD. However, maintenance of weight loss is difficult to achieve and strategies for weight loss maintenance is needed. Orlistat is a pharmacological agent that reduces the intestinal absorption of fat and may favour long-term weight maintenance.</p> <p>Objective</p> <p>To examine the change in body weight and dietary intake during a 1-year treatment with orlistat after an initial weight loss in obese subjects with SRBD. Furthermore, to explore the dietary determinants of weight maintenance during treatment with orlistat.</p> <p>Methods</p> <p>Men and women with SRBD aged 32-62 years (n = 63) participated in a 3-month dietary intervention to increase intake of vegetables and fruit. After an initial weight loss of 3.4 kg they achieved a mean body mass index of 34.3 ± 4.7 kg/m2. Subsequently they were treated with orlistat for 1 year. During this year, dietary and behavioural interventions to attain weight loss were provided in the course of 14 group sessions. Dietary intake, energy density and food choices were assessed with a food frequency questionnaire before and after orlistat treatment.</p> <p>Results</p> <p>With orlistat, body weight decreased by a mean of 3.5 kg (95% CI 1.5, 5.5). The dietary E% from saturated fat, intake of fatty dairy products and energy density increased after 1 year while intakes of oils, fish and vegetables decreased (all P < 0.05). After multivariate adjustments, weight loss was associated with E% protein (R2<sub>adj </sub>= 0.19 [95% CI 0.10, 0.46]), and inversely associated with E% saturated fat (R2<sub>adj </sub>= 0.20 [95% CI 0.12, 0.47]) and fatty dairy products (R2<sub>adj </sub>= 0.23 [95% CI 0.12, 0.49]).</p> <p>Conclusions</p> <p>Orlistat induced further weight loss, but dietary compliance declined with time. Increasing dietary protein and restricting saturated fat and fatty dairy products may facilitate weight loss with orlistat.</p

    Molecular analysis of Mycobacterium isolates from extrapulmonary specimens obtained from patients in Mexico

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    <p>Abstract</p> <p>Background</p> <p>Little information is available on the molecular epidemiology in Mexico of <it>Mycobacterium </it>species infecting extrapulmonary sites in humans. This study used molecular methods to determine the <it>Mycobacterium </it>species present in tissues and body fluids in specimens obtained from patients in Mexico with extrapulmonary disease.</p> <p>Methods</p> <p>Bacterial or tissue specimens from patients with clinical or histological diagnosis of extrapulmonary tuberculosis were studied. DNA extracts from 30 bacterial cultures grown in Löwenstein Jensen medium and 42 paraffin-embedded tissues were prepared. Bacteria were cultured from urine, cerebrospinal fluid, pericardial fluid, gastric aspirate, or synovial fluid samples. Tissues samples were from lymph nodes, skin, brain, vagina, and peritoneum. The DNA extracts were analyzed by PCR and by line probe assay (INNO-LiPA MYCOBACTERIA v2. Innogenetics NV, Gent, Belgium) in order to identify the <it>Mycobacterium </it>species present. DNA samples positive for <it>M. tuberculosis </it>complex were further analyzed by PCR and line probe assay (INNO-LiPA Rif.TB, Innogenetics NV, Gent, Belgium) to detect mutations in the <it>rpo</it>B gene associated with rifampicin resistance.</p> <p>Results</p> <p>Of the 72 DNA extracts, 26 (36.1%) and 23 (31.9%) tested positive for <it>Mycobacterium species </it>by PCR or line probe assay, respectively. In tissues, <it>M. tuberculosis </it>complex and <it>M. genus </it>were found in lymph nodes, and <it>M. genus </it>was found in brain and vagina specimens. In body fluids, <it>M. tuberculosis </it>complex was found in synovial fluid. <it>M. gordonae</it>, <it>M. smegmatis</it>, <it>M. kansasii</it>, <it>M. genus</it>, <it>M. fortuitum/M. peregrinum </it>complex and <it>M. tuberculosis </it>complex were found in urine. <it>M. chelonae/M. abscessus </it>was found in pericardial fluid and <it>M. kansasii </it>was found in gastric aspirate. Two of <it>M. tuberculosis </it>complex isolates were also PCR and LiPA positive for the <it>rpo</it>B gene. These two isolates were from lymph nodes and were sensitive to rifampicin.</p> <p>Conclusion</p> <p>1) We describe the <it>Mycobacterium </it>species diversity in specimens derived from extrapulmonary sites in symptomatic patients in Mexico; 2) Nontuberculous mycobacteria were found in a considerable number of patients; 3) Genotypic rifampicin resistance in <it>M. tuberculosis </it>complex infections in lymph nodes was not found.</p
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