262 research outputs found

    Tree Resin Composition, Collection Behavior and Selective Filters Shape Chemical Profiles of Tropical Bees (Apidae: Meliponini)

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    The diversity of species is striking, but can be far exceeded by the chemical diversity of compounds collected, produced or used by them. Here, we relate the specificity of plant-consumer interactions to chemical diversity applying a comparative network analysis to both levels. Chemical diversity was explored for interactions between tropical stingless bees and plant resins, which bees collect for nest construction and to deter predators and microbes. Resins also function as an environmental source for terpenes that serve as appeasement allomones and protection against predators when accumulated on the bees' body surfaces. To unravel the origin of the bees' complex chemical profiles, we investigated resin collection and the processing of resin-derived terpenes. We therefore analyzed chemical networks of tree resins, foraging networks of resin collecting bees, and their acquired chemical networks. We revealed that 113 terpenes in nests of six bee species and 83 on their body surfaces comprised a subset of the 1,117 compounds found in resins from seven tree species. Sesquiterpenes were the most variable class of terpenes. Albeit widely present in tree resins, they were only found on the body surface of some species, but entirely lacking in others. Moreover, whereas the nest profile of Tetragonula melanocephala contained sesquiterpenes, its surface profile did not. Stingless bees showed a generalized collecting behavior among resin sources, and only a hitherto undescribed species-specific “filtering” of resin-derived terpenes can explain the variation in chemical profiles of nests and body surfaces from different species. The tight relationship between bees and tree resins of a large variety of species elucidates why the bees' surfaces contain a much higher chemodiversity than other hymenopterans

    Binary and Millisecond Pulsars at the New Millennium

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    We review the properties and applications of binary and millisecond pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1300. There are now 56 binary and millisecond pulsars in the Galactic disk and a further 47 in globular clusters. This review is concerned primarily with the results and spin-offs from these surveys which are of particular interest to the relativity community.Comment: 59 pages, 26 figures, 5 tables. Accepted for publication in Living Reviews in Relativity (http://www.livingreviews.org

    The Fischer 344 Rat Reflects Human Susceptibility to Francisella Pulmonary Challenge and Provides a New Platform for Virulence and Protection Studies

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    Background: The pathogenesis of Francisella tularensis, the causative agent of tularemia, has been primarily characterized in mice. However, the high degree of sensitivity of mice to bacterial challenge, especially with the human virulent strains of F. tularensis, limits this animal model for screening of defined attenuated vaccine candidates for protection studies. Methods and Findings: We analyzed the susceptibility of the Fischer 344 rat to pulmonary (intratracheal) challenge with three different subspecies (subsp) of F. tularensis that reflect different levels of virulence in humans, and characterized the bacterial replication profile in rat bone marrow-derived macrophages (BMDM). In contrast to the mouse, Fischer 344 rats exhibit a broader range of sensitivity to pulmonary challenge with the human virulent subsp. tularensis and holarctica. Unlike mice, Fischer rats exhibited a high degree of resistance to pulmonary challenge with LVS (an attenuated derivative o

    TNF-α is involved in activating DNA fragmentation in skeletal muscle

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    Intraperitoneal administration of 100 μg kg−1 (body weight) of tumour necrosis factor-α to rats for 8 consecutive days resulted in a significant decrease in protein content, which was concomitant with a reduction in DNA content. Interestingly, the protein/DNA ratio was unchanged in the skeletal muscle of the tumour necrosis factor-α-treated animals as compared with the non-treated controls. Analysis of muscle DNA fragmentation clearly showed enhanced laddering in the skeletal muscle of tumour necrosis factor-α-treated animals, suggesting an apoptotic phenomenon. In a different set of experiments, mice bearing a cachexia-inducing tumour (the Lewis lung carcinoma) showed an increase in muscle DNA fragmentation (9.8-fold) as compared with their non-tumour-bearing control counterparts as previously described. When gene-deficient mice for tumour necrosis factor-α receptor protein I were inoculated with Lewis lung carcinoma, they were also affected by DNA fragmentation; however the increase was only 2.1-fold. These results suggest that tumour necrosis factor-α partly mediates DNA fragmentation during experimental cancer-associated cachexia

    A Community Study of Factors Related to Poorly Controlled Asthma among Brazilian Urban Children

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    BACKGROUND: Asthma constitutes a serious public health problem in many regions of the world, including the city of Salvador, State of Bahia-Brazil. The purpose of this study was to analyse the factors associated with poor asthma control. METHODOLOGY/PRINCIPAL FINDINGS: Two definitions were used for asthma: 1) wheezing in the last 12 months; 2) wheezing in the last 12 months plus other asthma symptoms or asthma diagnosis ever. The definition of poorly controlled asthma was: at least one reported hospitalisation due to asthma and/or high frequency of symptoms, in the last year. Children with poorly controlled asthma (N = 187/374) were compared with wheezing children with controlled asthma regarding age, gender, atopy, parental asthma, rhinitis, eczema, exposure to second hand tobacco smoke, presence of moulds, pets and pests in the house, helminth infections and body mass index. Crude and logistic regression adjusted odds ratios were used as measures of association. There was a higher proportion of poorly controlled asthma among children with eczema (OR = 1.55; 95% CI 1.02; 2.37). The strength of the association was greater among children with eczema and rhinitis (42.6%, 53.4% and 57.7%, respectively, in children who had no rhinitis nor eczema, had only one of those, and had both (p = 0.02 for trend test). The presence of mould in the houses was inversely associated with poorly controlled asthma (OR = 0.54; 95% CI 0.34; 0.87). CONCLUSIONS/SIGNIFICANCE: Our results indicate an association between eczema and poor asthma control in this environment, but emphasize the role of various other individual and environmental factors as determinants of poor control

    SARS-CoV-2 RNA detected in blood products from patients with COVID-19 is not associated with infectious virus [version 2; peer review: 2 approved]

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    Background: Laboratory diagnosis of SARS-CoV-2 infection (the cause of COVID-19) uses PCR to detect viral RNA (vRNA) in respiratory samples. SARS-CoV-2 RNA has also been detected in other sample types, but there is limited understanding of the clinical or laboratory significance of its detection in blood. Methods: We undertook a systematic literature review to assimilate the evidence for the frequency of vRNA in blood, and to identify associated clinical characteristics. We performed RT-PCR in serum samples from a UK clinical cohort of acute and convalescent COVID-19 cases (n=212), together with convalescent plasma samples collected by NHS Blood and Transplant (NHSBT) (n=462 additional samples). To determine whether PCR-positive blood samples could pose an infection risk, we attempted virus isolation from a subset of RNA-positive samples. Results: We identified 28 relevant studies, reporting SARS-CoV-2 RNA in 0-76% of blood samples; pooled estimate 10% (95%CI 5-18%). Among serum samples from our clinical cohort, 27/212 (12.7%) had SARS-CoV-2 RNA detected by RT-PCR. RNA detection occurred in samples up to day 20 post symptom onset, and was associated with more severe disease (multivariable odds ratio 7.5). Across all samples collected ≥28 days post symptom onset, 0/494 (0%, 95%CI 0-0.7%) had vRNA detected. Among our PCR-positive samples, cycle threshold (ct) values were high (range 33.5-44.8), suggesting low vRNA copy numbers. PCR-positive sera inoculated into cell culture did not produce any cytopathic effect or yield an increase in detectable SARS-CoV-2 RNA. There was a relationship between RT-PCR negativity and the presence of total SARS-CoV-2 antibody (p=0.02). Conclusions: vRNA was detectable at low viral loads in a minority of serum samples collected in acute infection, but was not associated with infectious SARS-CoV-2 (within the limitations of the assays used). This work helps to inform biosafety precautions for handling blood products from patients with current or previous COVID-19

    Association of IL-4RA single nucleotide polymorphisms, HLA-DR and HLA-DQ in children with Alternaria-sensitive moderate-severe asthma

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    <p>Abstract</p> <p>Background</p> <p>Asthma afflicts 6% to 8% of the United States population, and severe asthma represents approximately 10% of asthmatic patients. Several epidemiologic studies in the United States and Europe have linked <it>Alternaria </it>sensitivity to both persistence and severity of asthma. In order to begin to understand genetic risk factors underlying <it>Alternaria </it>sensitivity and asthma, in these studies we examined T cell responses to <it>Alternaria </it>antigens, HLA Class II restriction and HLA-DQ protection in children with severe asthma.</p> <p>Methods</p> <p>Sixty children with <it>Alternaria</it>-sensitive moderate-severe asthma were compared to 49 children with <it>Alternaria</it>-sensitive mild asthma. We examined HLA-DR and HLA-DQ frequencies in <it>Alternaria</it>-sensitive asthmatic by HLA typing. To determine ratios of Th1/Th2 <it>Alternaria</it>-specific T-cells, cultures were stimulated in media alone, <it>Alternaria alternata </it>extract and Alt a1. Sensitivity to IL-4 stimulation was measured by up-regulation of CD23 on B cells.</p> <p>Results</p> <p>Children with <it>Alternaria</it>-sensitive moderate-severe asthma trended to have increased sensitivities to <it>Cladosporium </it>(46% versus 35%), to <it>Aspergillus </it>(43% versus 28%), and significantly increased sensitivities to trees (78% versus 57%) and to weeds (68% versus 48%). The IL-4RA ile75val polymorphism was significantly increased in <it>Alternaria</it>-sensitive moderate-severe asthmatics, 83% (0.627 allele frequency) compared to <it>Alternaria</it>-sensitive mild asthmatics, 57% (0.388 allele frequency). This was associated with increased sensitivity to IL-4 stimulation measured by significantly increased IL-4 stimulated CD23 expression on CD19+ and CD86+CD19+ B cells of <it>Alternaria</it>-sensitive moderate-severe asthmatics. IL-5 and IL-13 synthesis was significantly increased in <it>Alternaria</it>-sensitive moderate-severe asthmatics compared to mild asthmatics to <it>Alternaria </it>extract and Alt a1 stimulation. The frequency of HLA-DQB1*03 allele was significantly decreased in <it>Alternaria</it>-sensitive moderate-severe asthmatics compared to mild asthmatics, 39% versus 63%, with significantly decreased allele frequency, 0.220 versus 0.398.</p> <p>Summary</p> <p>In children with <it>Alternaria</it>-sensitive moderate severe asthma, there was an increased Th2 response to <it>Alternaria </it>stimulation and increased sensitivity to IL-4 stimulation. This skewing towards a Th2 response was associated with an increased frequency of the IL-4RA ile75val polymorphism. In evaluating the HLA association, there was a decreased frequency of HLA-DQB1*03 in <it>Alternaria</it>-sensitive moderate severe asthmatic children consistent with previous studies suggest that HLA-DQB1*03 may be protective against the development of mold-sensitive severe asthma.</p

    Bats Avoid Radar Installations: Could Electromagnetic Fields Deter Bats from Colliding with Wind Turbines?

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    Large numbers of bats are killed by collisions with wind turbines, and there is at present no direct method of reducing or preventing this mortality. We therefore determine whether the electromagnetic radiation associated with radar installations can elicit an aversive behavioural response in foraging bats. Four civil air traffic control (ATC) radar stations, three military ATC radars and three weather radars were selected, each surrounded by heterogeneous habitat. Three sampling points matched for habitat type and structure, dominant vegetation species, altitude and surrounding land class were located at increasing distances from each station. A portable electromagnetic field meter measured the field strength of the radar at three distances from the source: in close proximity (<200 m) with a high electromagnetic field (EMF) strength >2 volts/metre, an intermediate point within line of sight of the radar (200–400 m) and with an EMF strength <2 v/m, and a control site out of sight of the radar (>400 m) and registering an EMF of zero v/m. At each radar station bat activity was recorded three times with three independent sampling points monitored on each occasion, resulting in a total of 90 samples, 30 of which were obtained within each field strength category. At these sampling points, bat activity was recorded using an automatic bat recording station, operated from sunset to sunrise. Bat activity was significantly reduced in habitats exposed to an EMF strength of greater than 2 v/m when compared to matched sites registering EMF levels of zero. The reduction in bat activity was not significantly different at lower levels of EMF strength within 400 m of the radar. We predict that the reduction in bat activity within habitats exposed to electromagnetic radiation may be a result of thermal induction and an increased risk of hyperthermia

    Effectiveness of trigger point dry needling for plantar heel pain: study protocol for a randomised controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Plantar heel pain (plantar fasciitis) is a common and disabling condition, which has a detrimental impact on health-related quality of life. Despite the high prevalence of plantar heel pain, the optimal treatment for this disorder remains unclear. Consequently, an alternative therapy such as dry needling is increasingly being used as an adjunctive treatment by health practitioners. Only two trials have investigated the effectiveness of dry needling for plantar heel pain, however both trials were of a low methodological quality. This manuscript describes the design of a randomised controlled trial to evaluate the effectiveness of dry needling for plantar heel pain.</p> <p>Methods</p> <p>Eighty community-dwelling men and woman aged over 18 years with plantar heel pain (who satisfy the inclusion and exclusion criteria) will be recruited. Eligible participants with plantar heel pain will be randomised to receive either one of two interventions, (i) real dry needling or (ii) sham dry needling. The protocol (including needling details and treatment regimen) was formulated by general consensus (using the Delphi research method) using 30 experts worldwide that commonly use dry needling for plantar heel pain. Primary outcome measures will be the pain subscale of the Foot Health Status Questionnaire and "first step" pain as measured on a visual analogue scale. The secondary outcome measures will be health related quality of life (assessed using the Short Form-36 questionnaire - Version Two) and depression, anxiety and stress (assessed using the Depression, Anxiety and Stress Scale - short version). Primary outcome measures will be performed at baseline, 2, 4, 6 and 12 weeks and secondary outcome measures will be performed at baseline, 6 and 12 weeks. Data will be analysed using the intention to treat principle.</p> <p>Conclusion</p> <p>This study is the first randomised controlled trial to evaluate the effectiveness of dry needling for plantar heel pain. The trial will be reported in accordance with the Consolidated Standards of Reporting Trials and the Standards for Reporting Interventions in Clinical Trials of Acupuncture guidelines. The findings from this trial will provide evidence for the effectiveness of trigger point dry needling for plantar heel pain.</p> <p>Trial registration</p> <p>Australian New Zealand 'Clinical Trials Registry'. <a href="http://www.anzctr.org.au/ACTRN12610000611022.aspx">ACTRN12610000611022</a>.</p
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