1,626 research outputs found

    Hypoxia does not influence the response of fish to a mixture of estrogenic chemicals

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    The official published version can be obtained from the link below - Copyright @ 2009 American Chemical SocietyChemical risk assessment procedures assign a major role to standardized toxicity tests, in which the response of a particular organism to a single test substance is determined under otherwise constant and favorable conditions in the laboratory. This approach fails to consider the potential for chemical interactions, as well as failing to consider how the toxicological response varies, depending on the conditions of exposure. As yet, the issue of confounding factors on chemically mediated effects in wildlife has received little attention, despite the fact that a range of physicochemical parameters, including temperature, water quality, and pH, are known to modify chemical toxicity. Here, we consider how the estrogenic response of fish varies with regard to hypoxia. Fathead minnows (Pimephales promelas) were exposed to a mixture of estrogenic chemicals under hypoxic or normoxic conditions. Their estrogenic response was characterized using an in vivo assay, involving the analysis of the egg yolk protein, vitellogenin (VTG). The results revealed that there was no effect of hypoxia on the VTG response in either treatment group at the end of the exposure period. This suggests that this end point is robust and relatively insensitive to the effects of any physiological changes that arise as a result of hypoxia. The implications of these negative findings are discussed in terms of their relevance with regard to the development of risk assessment policy.This work was funded by a grant from the Natural Environment Research Council(NE/D00389X/1)

    The course of mental health problems in children presenting with abdominal pain in general practice

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    Objective. To investigate the course of mental health problems in children presenting to general practice with abdominal pain and to evaluate the extent to which abdominal pain characteristics during follow-up predict the presence of mental health problems at 12 months' follow-up. Design. A prospective cohort study with one-year follow-up. Setting. 53 general practices in the Netherlands, between May 2004 and March 2006. Subjects. 281 children aged 4-17 years. Main outcome measures. The presence of a depressive problem, an anxiety problem, and multiple non-specific somatic symptoms at follow-up and odds ratios of duration, frequency, and severity of abdominal pain with these mental health problems at follow-up. Results. A depressive problem persisted in 24/74 children (32.9%; 95% CI 22.3-44.9%), an anxiety problem in 13/43 (30.2%; 95% CI 17.2-46.1%) and the presence of multiple non-specific somatic symptoms in 75/170 children (44.1%; 95% CI 36.7-51.6%). None of the abdominal pain characteristics predicted a depressive or an anxiety problem at 12 months' follow-up. More moments of moderate to severe abdominal pain predicted the presence of multiple nonspecific somatic symptoms at follow-up. Conclusions. In one-third of the children presenting to general practice for abdominal pain, anxiety and depressive problems persist during one year of follow-up. Characteristics of the abdominal pain during the follow-up period do not predict anxiety or depressive problems after one-year follow-up. We recommend following over time children seen in primary care with abdominal pain

    The James Clerk Maxwell telescope dense gas survey of the Perseus molecular cloud

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    This is the final version of the article. Available from the publisher via the DOI in this record.We present the results of a large-scale survey of the very dense (n > 106 cm-3) gas in the Perseus molecular cloud using HCO+ and HCN (J = 4 → 3) transitions. We have used this emission to trace the structure and kinematics of gas found in pre- and protostellar cores, as well as in outflows. We compare the HCO+/HCN data, highlighting regions where there is a marked discrepancy in the spectra of the two emission lines. We use the HCO+ to identify positively protostellar outflows and their driving sources, and present a statistical analysis of the outflow properties that we derive from this tracer. We find that the relations we calculate between the HCO+ outflow driving force and the Menv and Lbol of the driving source are comparable to those obtained from similar outflow analyses using 12CO, indicating that the two molecules give reliable estimates of outflow properties. We also compare the HCO+ and the HCN in the outflows, and find that the HCN traces only the most energetic outflows, the majority of which are driven by young Class 0 sources. We analyse the abundances of HCN and HCO+ in the particular case of the IRAS 2A outflows, and find that the HCN is much more enhanced than the HCO+ in the outflow lobes. We suggest that this is indicative of shock enhancement of HCN along the length of the outflow; this process is not so evident for HCO+, which is largely confined to the outflow base. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.SLW-S and JH are funded by the Science and Technology Facilities Council of the UK. The James Clerk Maxwell Telescope is operated by the Joint Astronomy Centre on behalf of the Science and Technology Facilities Council of the United Kingdom, the National Research Council of Canada and (until 2013 March 31) the Netherlands Organisation for Scientific Researc

    Measuring distance through dense weighted networks: The case of hospital-associated pathogens

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    Hospital networks, formed by patients visiting multiple hospitals, affect the spread of hospital-associated infections, resulting in differences in risks for hospitals depending on their network position. These networks are increasingly used to inform strategies to prevent and control the spread of hospital-associated pathogens. However, many studies only consider patients that are received directly from the initial hospital, without considering the effect of indirect trajectories through the network. We determine the optimal way to measure the distance between hospitals within the network, by reconstructing the English hospital network based on shared patients in 2014–2015, and simulating the spread of a hospital-associated pathogen between hospitals, taking into consideration that each intermediate hospital conveys a delay in the further spread of the pathogen. While the risk of transferring a hospital-associated pathogen between directly neighbouring hospitals is a direct reflection of the number of shared patients, the distance between two hospitals far-away in the network is determined largely by the number of intermediate hospitals in the network. Because the network is dense, most long distance transmission chains in fact involve only few intermediate steps, spreading along the many weak links. The dense connectivity of hospital networks, together with a strong regional structure, causes hospital-associated pathogens to spread from the initial outbreak in a two-step process: first, the directly surrounding hospitals are affected through the strong connections, second all other hospitals receive introductions through the multitude of weaker links. Although the strong connections matter for local spread, weak links in the network can offer ideal routes for hospital-associated pathogens to travel further faster. This hold important implications for infection prevention and control efforts: if a local outbreak is not controlled in time, colonised patients will appear in other regions, irrespective of the distance to the initial outbreak, making import screening ever more difficult

    Local anesthetics induce autophagy in young permanent tooth pulp cells

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    Pulp cells are essential for tooth development, and dentin repair and regeneration. In addition these cells have been identified as an important stem cell source. Local anesthetics are widely used in dental clinics, as well as the other clinical disciplines and have been suggested to interfere with human permanent tooth development and induce tooth agenesis through unknown mechanisms. Using pig model and human young permanent tooth pulp cells, our research has identified that the local anesthetics commonly used in clinics can affect cell proliferation. Molecular pathway profiling suggested that LC3II is one of the earliest molecules induced by the agents and p62 is the only common downstream target identified for all the drugs tested. The effect of the drugs could be partially recovered by V-ATPase inhibitor only if early intervention is performed. Our results provide novel evidence that local anesthetics could affect tooth cell growth that potentially can have impacts on tooth development

    Motivations and barriers to prosthesis users participation in physical activity, exercise and sport : a review of the literature

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    The UK will host the Paralympics in 2012 and the Commonwealth Games in 2014 showcasing the talents of elite athletes and aiming to inspire the population to become involved. However, low levels of physical activity (PA) are prevalent: only 40% of men and 28% of women meet the minimum UK recommendations. The limb absent population is no exception. To determine if people with limb amputations are participating in physical activity and sport; whether post-amputation activity levels match pre-amputation levels; and if there are motivations and barriers to participation. Study design: Literature review Five reviewers systematically search of peer reviewed and gray literature in seven bibliographic databases and the Cochrane Library. Results: Following rigorous elimination, 12 articles were finally included in the review and critically appraised. Four themes were identified: components, rehabilitation outcomes, body image and motivations and barriers to participation. People with limb absence are not participating in PA conducive to health benefits, and only a minority participate in exercise and sports. Participation following amputation does not mirror that of pre-amputation levels, and more barriers than motivations exist to adopting and maintaining a physically active lifestyle. This literature review aims to inform those involved in rehabilitation and ongoing care of those with limb absence about what motivates or precludes their participation in physical activity, exercise and sport. Such knowledge could be applied to improving health and well being in this population

    Plasma proteins, cognitive decline, and 20-year risk of dementia in the Whitehall II and Atherosclerosis Risk in Communities studies

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    Introduction: Plasma proteins affect biological processes and are common drug targets but their role in the development of Alzheimer's disease and related dementias remains unclear. We examined associations between 4953 plasma proteins and cognitive decline and risk of dementia in two cohort studies with 20-year follow-ups. Methods: In the Whitehall II prospective cohort study proteins were measured using SOMAscan technology. Cognitive performance was tested five times over 20 years. Linkage to electronic health records identified incident dementia. The results were replicated in the Atherosclerosis Risk in Communities (ARIC) study. Results: Fifteen non-amyloid/non-tau–related proteins were associated with cognitive decline and dementia, were consistently identified in both cohorts, and were not explained by known dementia risk factors. Levels of six of the proteins are modifiable by currently approved medications for other conditions. Discussion: This study identified several plasma proteins in dementia-free people that are associated with long-term risk of cognitive decline and dementia

    Protocol for: Sheffield Obesity Trial (SHOT): A randomised controlled trial of exercise therapy and mental health outcomes in obese adolescents [ISRCNT83888112]

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    Background While obesity is known to have many physiological consequences, the psychopathology of this condition has not featured prominently in the literature. Cross-sectional studies have indicated that obese children have increased odds of experiencing poor quality of life and mental health. However, very limited trial evidence has examined the efficacy of exercise therapy for enhancing mental health outcomes in obese children, and the Sheffield Obesity Trial (SHOT) will provide evidence of the efficacy of supervised exercise therapy in obese young people aged 11–16 years versus usual care and an attention-control intervention. Method/design SHOT is a randomised controlled trial where obese young people are randomised to receive; (1) exercise therapy, (2) attention-control intervention (involving body-conditioning exercises and games that do not involve aerobic activity), or (3) usual care. The exercise therapy and attention-control sessions will take place three times per week for eight weeks and a six-week home programme will follow this. Ninety adolescents aged between 11–16 years referred from a children's hospital for evaluation of obesity or via community advertisements will need to complete the study. Participants will be recruited according to the following criteria: (1) clinically obese and aged 11–16 years (Body Mass Index Centile > 98th UK standard) (2) no medical condition that would restrict ability to be active three times per week for eight weeks and (3) not diagnosed with insulin dependent diabetes or receiving oral steroids. Assessments of outcomes will take place at baseline, as well as four (intervention midpoint) and eight weeks (end of intervention) from baseline. Participants will be reassessed on outcome measures five and seven months from baseline. The primary endpoint is physical self-perceptions. Secondary outcomes include physical activity, self-perceptions, depression, affect, aerobic fitness and BMI

    Community prevalence of SARS-CoV-2 in England from April to November, 2020: results from the ONS Coronavirus Infection Survey

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    Background: Decisions about the continued need for control measures to contain the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rely on accurate and up-to-date information about the number of people testing positive for SARS-CoV-2 and risk factors for testing positive. Existing surveillance systems are generally not based on population samples and are not longitudinal in design. Methods: Samples were collected from individuals aged 2 years and older living in private households in England that were randomly selected from address lists and previous Office for National Statistics surveys in repeated cross-sectional household surveys with additional serial sampling and longitudinal follow-up. Participants completed a questionnaire and did nose and throat self-swabs. The percentage of individuals testing positive for SARS-CoV-2 RNA was estimated over time by use of dynamic multilevel regression and poststratification, to account for potential residual non-representativeness. Potential changes in risk factors for testing positive over time were also assessed. The study is registered with the ISRCTN Registry, ISRCTN21086382. Findings: Between April 26 and Nov 1, 2020, results were available from 1 191 170 samples from 280 327 individuals; 5231 samples were positive overall, from 3923 individuals. The percentage of people testing positive for SARS-CoV-2 changed substantially over time, with an initial decrease between April 26 and June 28, 2020, from 0·40% (95% credible interval 0·29–0·54) to 0·06% (0·04–0·07), followed by low levels during July and August, 2020, before substantial increases at the end of August, 2020, with percentages testing positive above 1% from the end of October, 2020. Having a patient-facing role and working outside your home were important risk factors for testing positive for SARS-CoV-2 at the end of the first wave (April 26 to June 28, 2020), but not in the second wave (from the end of August to Nov 1, 2020). Age (young adults, particularly those aged 17–24 years) was an important initial driver of increased positivity rates in the second wave. For example, the estimated percentage of individuals testing positive was more than six times higher in those aged 17–24 years than in those aged 70 years or older at the end of September, 2020. A substantial proportion of infections were in individuals not reporting symptoms around their positive test (45–68%, dependent on calendar time. Interpretation: Important risk factors for testing positive for SARS-CoV-2 varied substantially between the part of the first wave that was captured by the study (April to June, 2020) and the first part of the second wave of increased positivity rates (end of August to Nov 1, 2020), and a substantial proportion of infections were in individuals not reporting symptoms, indicating that continued monitoring for SARS-CoV-2 in the community will be important for managing the COVID-19 pandemic moving forwards. Funding: Department of Health and Social Care
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