93 research outputs found

    On a two variable class of Bernstein-Szego measures

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    The one variable Bernstein-Szego theory for orthogonal polynomials on the real line is extended to a class of two variable measures. The polynomials orthonormal in the total degree ordering and the lexicographical ordering are constructed and their recurrence coefficients discussed.Comment: minor change

    Blood-Brain Barrier Breakdown in a Single Post-stroke Rodent Brain

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    Stroke is a major cause of global morbidity and mortality. Middle cerebral artery occlusion (MCAO) has historically been the most common animal model of simulating ischemic stroke. The extent of neurological injury after MCAO is typically measured by cerebral edema, infarct zone, and blood-brain barrier (BBB) permeability. A significant limitation of these methods is that separate sets of brains must be used for each measurement. Here we examine an alternative method of measuring cerebral edema, infarct zone and BBB permeability following MCAO in the same set of brain samples. Ninety-six rats were randomly divided into three experimental groups. Group 1 (n = 27) was used for the evaluation of infarct zone and brain edema in rats post-MCAO (n = 17) vs. sham-operated controls (n = 10). Group 2 (n = 27) was used for the evaluation of BBB breakdown in rats post-MCAO (n = 15) vs. sham-operated controls (n = 10). In Group 3 (n = 42), all three parameters were measured in the same set of brain slices in rats post-MCAO (n = 26) vs. sham-operated controls (n = 16). The effect of Evans blue on the accuracy of measuring infarct zone by 2,3,5-triphenyltetrazolium chloride (TTC) staining was determined by measuring infarct zone with and without an applied blue filter. The effects of various concentrations of TTC (0, 0.05, 0.35, 0.5, 1, and 2%) on the accuracy of measuring BBB permeability was also assessed. There was an increase in infarct volume (p < 0.01), brain edema (p < 0.01) and BBB breakdown (p < 0.01) in rats following MCAO compared to sham-operated controls, whether measured separately or together in the same set of brain samples. Evans blue had an effect on measuring infarct volume that was minimized by the application of a blue filter on scanned brain slices. There was no difference in the Evans blue extravasation index for the brain tissue samples without TTC compared to brain tissue samples incubated in TTC. Our results demonstrate that measuring cerebral edema, infarct zone and BBB permeability following MCAO can accurately be measured in the same set of brain samples

    In vivo bioimaging with tissue-specific transcription factor activated luciferase reporters.

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    The application of transcription factor activated luciferase reporter cassettes in vitro is widespread but potential for in vivo application has not yet been realized. Bioluminescence imaging enables non-invasive tracking of gene expression in transfected tissues of living rodents. However the mature immune response limits luciferase expression when delivered in adulthood. We present a novel approach of tissue-targeted delivery of transcription factor activated luciferase reporter lentiviruses to neonatal rodents as an alternative to the existing technology of generating germline transgenic light producing rodents. At this age, neonates acquire immune tolerance to the conditionally responsive luciferase reporter. This simple and transferrable procedure permits surrogate quantitation of transcription factor activity over the lifetime of the animal. We show principal efficacy by temporally quantifying NFκB activity in the brain, liver and lungs of somatotransgenic reporter mice subjected to lipopolysaccharide (LPS)-induced inflammation. This response is ablated in Tlr4(-/-) mice or when co-administered with the anti-inflammatory glucocorticoid analogue dexamethasone. Furthermore, we show the malleability of this technology by quantifying NFκB-mediated luciferase expression in outbred rats. Finally, we use somatotransgenic bioimaging to longitudinally quantify LPS- and ActivinA-induced upregulation of liver specific glucocorticoid receptor and Smad2/3 reporter constructs in somatotransgenic mice, respectively

    Childhood Asthma and Environmental Exposures at Swimming Pools: State of the Science and Research Recommendations

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    OBJECTIVES: Recent studies have explored the potential for swimming pool disinfection by-products (DBPs), which are respiratory irritants, to cause asthma in young children. Here we describe the state of the science on methods for understanding children's exposure to DBPs and biologics at swimming pools and associations with new-onset childhood asthma and recommend a research agenda to improve our understanding of this issue. DATA SOURCES: A workshop was held in Leuven, Belgium, 21-23 August 2007, to evaluate the literature and to develop a research agenda to better understand children's exposures in the swimming pool environment and their potential associations with new-onset asthma. Participants, including clinicians, epidemiologists, exposure scientists, pool operations experts, and chemists, reviewed the literature, prepared background summaries, and held extensive discussions on the relevant published studies, knowledge of asthma characterization and exposures at swimming pools, and epidemiologic study designs. SYNTHESIS: Childhood swimming and new-onset childhood asthma have clear implications for public health. If attendance at indoor pools increases risk of childhood asthma, then concerns are warranted and action is necessary. If there is no such relationship, these concerns could unnecessarily deter children from indoor swimming and/or compromise water disinfection. CONCLUSIONS: Current evidence of an association between childhood swimming and new-onset asthma is suggestive but not conclusive. Important data gaps need to be filled, particularly in exposure assessment and characterization of asthma in the very young. Participants recommended that additional evaluations using a multidisciplinary approach are needed to determine whether a clear association exists

    Clinical behavior and outcomes of breast cancer in young women with germline BRCA pathogenic variants

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    Young breast cancer (BC) patients carrying a germline BRCA pathogenic variant (mBRCA) have similar outcomes as non-carriers. However, the impact of the type of gene (BRCA1 vs. BRCA2) and hormone receptor status (positive [HR+] vs. negative [HR 12]) on clinical behavior and outcomes of mBRCA BC remains largely unknown. This is an international, multicenter, hospital-based, retrospective cohort study that included mBRCA patients diagnosed, between January 2000 and December 2012, with stage I\u2013III invasive early BC at age 6440 years. From 30 centers worldwide, 1236 young mBRCA BC patients were included. Among 808 and 428 patients with mBRCA1 or mBRCA2, 191 (23.6%) and 356 (83.2%) had HR+tumors, respectively (P < 0.001). Median follow-up was 7.9 years. Second primary BC (P = 0.009) and non-BC malignancies (P = 0.02) were more frequent among mBRCA1 patients while distant recurrences were less frequent (P = 0.02). Irrespective of hormone receptor status, mBRCA1 patients had worse disease-free survival (DFS; adjusted HR = 0.76, 95% CI = 0.60\u20130.96), with no difference in distant recurrence-free interval (DRFI) and overall survival (OS). Patients with HR+ disease had more frequent distant recurrences (P < 0.001) and less frequent second primary malignancies (BC: P = 0.005; non-BC: P = 0.18). No differences in DFS and OS were observed according to hormone receptor status, with a tendency for worse DRFI (adjusted HR = 1.39, 95% CI = 0.94\u20132.05) in patients with HR+ BC. Type of mBRCA gene and hormone receptor status strongly impact BC clinical behavior and outcomes in mBRCA young patients. These results provide important information for patients\u2019 counseling on treatment, prevention, and surveillance strategies

    Invasive Prenatal Diagnostic Testing Recommendations are Influenced by Maternal Age, Statistical Misconception and Perceived Liability

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    Funding policy and medico-legal climate are part of physicians’ reality and might permeate clinical decisions. This study evaluates the influence of maternal age and government funding on obstetrician/gynecologist recommendation for invasive prenatal testing (i.e. amniocentesis) for Down syndrome (DS), and its association with the physician’s assessment of the risk of liability for medical malpractice unless they recommend amniocentesis. Israeli physicians (N = 171) completed a questionnaire and provided amniocentesis recommendations for women at 18 weeks gestation with normal preliminary screening results, identical except aged 28 and 37. Amniocentesis recommendations were reversed for the younger (‘yes’ regardless of testing results: 6.4%; ‘no’ regardless of testing results: 31.6%) versus older woman (‘yes’ regardless of testing results: 40.9%; ‘no’ regardless of testing results: 7.0%; χ2 = 71.55, p < .01). About half of the physicians endorsed different recommendations per scenario; of these, 65.6% recommended amniocentesis regardless of testing results for the 37-year-old woman. Physicians routinely performing amniocentesis and those advocating for amniocentesis for all women ≥ age 35 were approximately twice as likely to vary their recommendations per scenario. Physicians who perceived risk of liability for malpractice as large were nearly one-and-a-half times more likely to vary recommendations. The results indicate physicians’ recommendations are influenced by maternal age, though age is already incorporated in prenatal DS risk evaluations. The physician’s assessment of the risk that they will be sued unless they recommend amniocentesis may contribute to this spurious influence
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