1,508 research outputs found

    Evidence that human and equine erythrocytes could have significant roles in the transport and delivery of amino acids to organs and tissues

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    Erythrocytes have a well-defined role in the gaseous exchange of oxygen and carbon dioxide in the mammalian body. The erythrocytes can contain more than half of the free amino acids present in whole blood. Based on measures showing that venous erythrocyte levels of amino acids are much less than arterial erythrocyte levels, it has previously been proposed that erythrocytes also play a role in the delivery of amino acids to tissues in the body. This role has been dismissed because it has been assumed that to act as an amino acid transport vehicle, the erythrocytes should release their entire amino acid content in the capillary beds at the target tissues with kinetic studies showing that this would take too long to achieve. This investigation set out to investigate whether the equine erythrocytes could rapidly take up and release smaller packages of amino acids when exposed to high or low external concentrations of amino acids, because it seemed very unlikely that cells would be able to release all of their amino acids without serious impacts on osmotic balance. Freshly prepared erythrocytes were placed in alternating solutions of high and low amino acid concentrations in PBS to assess the capacities of these cells to rapidly take up and release amino acids depending on the nature of the external environment. It was found that amino acids were rapidly taken up and released in small quantities in each cycle representing 15% of their total load in equine erythrocytes and 16% in human erythrocytes. The capacity for rapid uptake/release of amino acids by equine and human erythrocytes provided evidence to support the theory that mammalian erythrocytes have a significant role in transport of amino acids from the liver to tissues, muscles and organs

    The novel 5-lipoxygenase inhibitor ABT-761 attenuates cerebral vasospasm in a rabbit model of subarachnoid hemorrhage

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    OBJECTIVE: Eicosanoids have been implicated in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). Leukotrienes, 5-hydroxyperoxyeicosatetraenoic acid, and 5-hydroxyeicosatetraenoic acid are part of this group of substances, resulting from the 5-lipoxygenase activity on arachidonic acid metabolism. This study examined the effects of ABT-761, a new 5-lipoxygenase inhibitor, on cerebral vasospasm in an in vivo rabbit model of SAH. METHODS: A total of 48 rabbits were assigned to one of six groups: SAH + placebo (n = 8), SAH + ABT-761 20 mg/kg (n = 8), SAH + ABT-761 30 mg/kg (n = 8), control + placebo (n = 8), control + ABT-761 20 mg/kg (n = 8), and control + ABT-761 30 mg/kg (n = 8). Drug administration was initiated 30 minutes after induction of SAH and repeated 24 hours later. The animals were killed 48 hours after SAH, using the perfusion-fixation method. The cross sectional areas of basilar artery histological sections were measured by an investigator blinded to the treatment groups of the individual samples. RESULTS: In placebo-treated animals, the average luminal cross sectional area of the basilar artery was reduced by 68% after SAH as compared with controls (P < 0.0001). After SAH, the vasospastic response was attenuated in animals treated with 20 or 30 mg/kg representing a 28 or 35% reduction, respectively (P = 0.0011 and P = 0.0038). CONCLUSION: The results demonstrated that ABT-761 is effective in attenuating experimental cerebral vasospasm, indicating that this new drug represents a potential therapeutic agent for the treatment of vasospasm after SAH

    Aminoglycoside antibiotics and autism: a speculative hypothesis

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    BACKGROUND: Recently, it has been suspected that there is a relationship between therapy with some antibiotics and the onset of autism; but even more curious, some children benefited transiently from a subsequent treatment with a different antibiotic. Here, we speculate how aminoglycoside antibiotics might be associated with autism. PRESENTATION: We hypothesize that aminoglycoside antibiotics could a) trigger the autism syndrome in susceptible infants by causing the stop codon readthrough, i.e., a misreading of the genetic code of a hypothetical critical gene, and/or b) improve autism symptoms by correcting the premature stop codon mutation in a hypothetical polymorphic gene linked to autism. TESTING: Investigate, retrospectively, whether a link exists between aminoglycoside use (which is not extensive in children) and the onset of autism symptoms (hypothesis "a"), or between amino glycoside use and improvement of these symptoms (hypothesis "b"). Whereas a prospective study to test hypothesis "a" is not ethically justifiable, a study could be designed to test hypothesis "b". IMPLICATIONS: It should be stressed that at this stage no direct evidence supports our speculative hypothesis and that its main purpose is to initiate development of new ideas that, eventually, would improve our understanding of the pathobiology of autism

    Interventions to Promote Cancer Awareness and Early Presentation: Systematic Review

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    Low cancer awareness contributes to delay in presentation for cancer symptoms and may lead to delay in cancer diagnosis. The aim of this study was to review the evidence for the effectiveness of interventions to raise cancer awareness and promote early presentation in cancer to inform policy and future research. We searched bibliographic databases and reference lists for randomised controlled trials of interventions delivered to individuals, and controlled or uncontrolled studies of interventions delivered to communities. We found some evidence that interventions delivered to individuals modestly increase cancer awareness in the short term and insufficient evidence that they promote early presentation. We found limited evidence that public education campaigns reduce stage at presentation of breast cancer, malignant melanoma and retinoblastoma

    Modeling the risk of malaria for travelers to areas with stable malaria transmission

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    BACKGROUND: Malaria is an important threat to travelers visiting endemic regions. The risk of acquiring malaria is complex and a number of factors including transmission intensity, duration of exposure, season of the year and use of chemoprophylaxis have to be taken into account estimating risk. MATERIALS AND METHODS: A mathematical model was developed to estimate the risk of non-immune individual acquiring falciparum malaria when traveling to the Amazon region of Brazil. The risk of malaria infection to travelers was calculated as a function of duration of exposure and season of arrival. RESULTS: The results suggest significant variation of risk for non-immune travelers depending on arrival season, duration of the visit and transmission intensity. The calculated risk for visitors staying longer than 4 months during peak transmission was 0.5% per visit. CONCLUSIONS: Risk estimates based on mathematical modeling based on accurate data can be a valuable tool in assessing risk/benefits and cost/benefits when deciding on the value of interventions for travelers to malaria endemic regions

    Intent to Receive Pandemic Influenza A (H1N1) Vaccine, Compliance with Social Distancing and Sources of Information in NC, 2009

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    BACKGROUND:Public adherence to influenza vaccination recommendations has been low, particularly among younger adults and children under 2, despite the availability of safe and effective seasonal vaccine. Intention to receive 2009 pandemic influenza A (H1N1) vaccine has been estimated to be 50% in select populations. This report measures knowledge of and intention to receive pandemic vaccine in a population-based setting, including target groups for seasonal and H1N1 influenza. METHODOLOGY AND PRINCIPAL FINDINGS:On August 28-29, 2009, we conducted a population-based survey in 2 counties in North Carolina. The survey used the 30x7 two-stage cluster sampling methodology to identify 210 target households. Prevalence ratios (PR) and 95% confidence intervals (CI) were estimated. Knowledge of pandemic influenza A (H1N1) vaccine was high, with 165 (80%) aware that a vaccine was being prepared. A total of 133 (64%) respondents intended to receive pandemic vaccine, 134 (64%) intended to receive seasonal vaccine, and 109 (53%) intended to receive both. Reporting great concern about H1N1 infection (PR 1.55; 95%CI: 1.30, 1.85), receiving seasonal influenza vaccine in 2008-09 (PR 1.47; 95%CI: 1.18, 1.82), and intending to receive seasonal influenza vaccine in 2009-10 (PR 1.27; 95%CI: 1.14, 1.42) were associated with intention to receive pandemic vaccine. Not associated were knowledge of vaccine, employment, having children under age 18, gender, race/ethnicity and age. Reasons cited for not intending to get vaccinated include not being at risk for infection, concerns about vaccine side effects and belief that illness caused by pandemic H1N1 would be mild. Forty-five percent of households with children under 18 and 65% of working adults reported ability to comply with self-isolation at home for 7-10 days if recommended by authorities. CONCLUSIONS AND SIGNIFICANCE:This is the first report of a population based rapid assessment used to assess knowledge and intent to receive pandemic vaccine in a community sample. Intention to receive pandemic and seasonal vaccines was higher than previously published reports. To reach persons not intending to receive pandemic vaccine, public health communications should focus on the perceived risk of infection and concerns about vaccine safety

    Fractional quantum Hall effect in a quantum point contact at filling fraction 5/2

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    Recent theories suggest that the excitations of certain quantum Hall states may have exotic braiding statistics which could be used to build topological quantum gates. This has prompted an experimental push to study such states using confined geometries where the statistics can be tested. We study the transport properties of quantum point contacts (QPCs) fabricated on a GaAs/AlGaAs two dimensional electron gas that exhibits well-developed fractional quantum Hall effect, including at bulk filling fraction 5/2. We find that a plateau at effective QPC filling factor 5/2 is identifiable in point contacts with lithographic widths of 1.2 microns and 0.8 microns, but not 0.5 microns. We study the temperature and dc-current-bias dependence of the 5/2 plateau in the QPC, as well as neighboring fractional and integer plateaus in the QPC while keeping the bulk at filling factor 3. Transport near QPC filling factor 5/2 is consistent with a picture of chiral Luttinger liquid edge-states with inter-edge tunneling, suggesting that an incompressible state at 5/2 forms in this confined geometry

    What do patients complain about online: A systematic review and taxonomy framework based on patient centeredness

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    © 2019 Journal of Medical Internet Research. All rights reserved. Background: Complaints made online by patients about their health care experiences are becoming prevalent because of widespread worldwide internet connectivity. An a priori framework, based on patient centeredness, may be useful in identifying the types of issues patients complain about online across multiple settings. It may also assist in examining whether the determinants of patient-centered care (PCC) mirror the determinants of patient experiences. Objective: The objective of our study was to develop a taxonomy framework for patient complaints online based on patient centeredness and to examine whether the determinants of PCC mirror the determinants of patient experiences. Methods: First, the best fit framework synthesis technique was applied to develop the proposed a priori framework. Second, electronic databases, including Web of Science, Scopus, and PubMed, were searched for articles published between 2000 and June 2018. Studies were only included if they collected primary quantitative data on patients' online complaints. Third, a deductive and inductive thematic analysis approach was adopted to code the themes of recognized complaints into the framework. Results: In total, 17 studies from 5 countries were included in this study. Patient complaint online taxonomies and theme terms varied. According to our framework, patients expressed most dissatisfaction with patient-centered processes (101,586/204,363, 49.71%), followed by prerequisites (appropriate skills and knowledge of physicians; 50,563, 24.74%) and the care environment (48,563/204,363, 23.76%). The least dissatisfied theme was expected outcomes (3651/204,363, 1.79%). People expressed little dissatisfaction with expanded PCC dimensions, such as involvement of family and friends (591/204,363, 0.29%). Variation in the concerns across different countries' patients were also observed. Conclusions: Online complaints made by patients are of major value to health care providers, regulatory bodies, and patients themselves. Our PCC framework can be applied to analyze them under a wide range of conditions, treatments, and countries. This review has shown significant heterogeneity of patients' online complaints across different countries

    Unexpected outcome from Trousseau syndrome

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    <p>Abstract</p> <p>Background</p> <p>Unprovoked superficial thrombophlebitis and subsequent venous thromboembolism are well-described albeit rare presenting features of advanced visceral malignancy that often manifest too late for curative intervention to be beneficial.</p> <p>Case Presentation</p> <p>We present the first reported case of early gastric carcinoma presenting with these paraneoplastic phenomena in an otherwise healthy farmer. The early presentation allowed for a curative partial gastrectomy, which itself was complicated by the presence of a deep vein thrombosis extending into the inferior vena cava. Fortunately, stabilization of the clot allowed for surgery to proceed without the need for a caval filter. The patient was referred for adjuvant chemotherapy and has since made an excellent recovery.</p> <p>Conclusions</p> <p>This case provides new evidence for the presentation of superficial thrombophlebitis in early gastric carcinoma and the potential for curative surgery in such instances. A high index of suspicion and a prompt diagnostic workup are essential for timely planning and execution of surgery in these early albeit rare presentations.</p
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