17,900 research outputs found

    Species-specific cuticular hydrocarbon stability within European Myrmica Ants

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    Recognition is a fundamental process on which all subsequent behaviors are based at every organizational level, from the gene up to the super-organism. At the whole organism level visual recognition is the best understood. However, chemical communication is far more widespread than visual communication, but despite its importance is much less understood. Ants provide an excellent model system for chemical ecology studies as it is well established that compounds known as cuticular hydrocarbons (CHCs) are used as recognition cues in ants. Therefore, stable species-specific odors should exist, irrespective of geographic locality. We tested this hypothesis by comparing the CHC profiles of workers of twelve species of Myrmica ants from four countries across Europe, from Iberia to the Balkans and from the Mediterranean to Fennoscandia. CHCs remained qualitatively stable within each species, right down to the isomer level. Despite the morphological similarity that occurs within the genus Myrmica, their CHCs were highly diverse but remarkably species-specific and stable across wide geographical areas. This indicates a genetic mechanism under strong selection that produces these species-specific chemical profiles, despite each species encountering different environmental conditions across its range

    Fathers of adults who have a learning disability : roles, needs and concerns

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    Background: There is little research that specifically relates to fathers of adults with a learning disability despite the social expectation that fathers will provide a supportive role over the lifespan. Methods: Semi-structured interviews were carried out with seven fathers of adults with a learning disability to explore their roles, needs and concerns. Data was analysed using a framework associated with Interpretative Phenomenological Analysis (IPA). Results: Themes arising demonstrate that fathers were shocked at the diagnosis of learning disability but usually reported adaptation over time. The impact of learning disability upon men’s lives, their perception of their adult child and the roles they assumed were varied. Fathers valued support from wives and grandparents; having knowledge and interests and work type roles. All fathers were concerned about the future yet comprehensive futures planning was lacking. Some fathers reported difficulties in being emotionally open, and referred to societal stereotypes. Fathers valued positive support from service providers; however this relationship was often in conflict. Conclusion: Although mothers are often the main carers for adults with a learning disability, fathers can make a significant contribution. The findings presented here support the results of previous studies regarding paternal response to learning disability and varied impact upon men’s lives. Identified support strategies include leisure interests, volunteer/ work roles, having information and support from wives and grandparents. Ongoing concerns incorporate the future and ambivalent relationships with service providers, which could have a negative impact upon the individual who has a learning disability

    Features of cancer in teenagers and young adults in primary care: a population-based nested case-control study

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    This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: Teenagers and young adults (TYA, 15-24 years) diagnosed with cancer report repeated visits to primary care before referral. We investigated associations of symptoms and consultation frequency in primary care with TYA cancers. METHODS: Population-based, case-control study was carried out using data from the Clinical Practice Research Datalink (CPRD). A total of 1064 TYA diagnosed with cancer were matched to 13,206 controls. Symptoms independently associated with specific cancers were identified. Likelihood ratios (LRs) and positive predictive values (PPVs) were calculated. RESULTS: In the 3 months before diagnosis, 397 (42.9%) cases consulted > or =4 times vs 593(11.5%) controls (odds ratio (OR): 12.1; 95% CI: 9.7, 15.1), yielding a PPV for any cancer of 0.018%. The LR of lymphoma with a head/neck mass was 434 (95% CI: 60, 3158), with a PPV of 0.5%. Corresponding figures in other cancers included - LR of leukaemia with lymphadenopathy (any site): 29 (95% CI: 8, 112), PPV 0.015%; LR of CNS tumour with seizure: 56 (95% CI: 19, 163), PPV 0.024%; and LR of sarcoma with lump/mass/swelling: 79 (95% CI: 24, 264), PPV 0.042%. CONCLUSION: Teenagers and young adults with cancer consulted more frequently than controls in the 3 months before diagnosis. Primary care features of cancer match secondary care reports, but were of very low risk; nonetheless, some features increased the likelihood of cancer substantially and should be taken seriously when assessing TYA.RMD is funded by the National Institute for Health Research (NIHR). WH was, in part, funded by an NIHR postdoctoral fellowship. This study is based on data from the Full Feature Clinical Practice Research Datalink (CPRD) obtained under licence from the UK Medicines and Healthcare Products Regulatory Agency (MHRA). Access to the CPRD was funded through the Medical Research Council (MRC) licence agreement with the UK Medicines and Healthcare Products Regulatory Agency. The conduct of this study was approved by the Independent Scientific Advisory Committee (ISAC) of the MHRS (Protocol 10_056A) and the University of Bristol (reference: 35515

    X-ray diffraction from bone employing annular and semi-annular beams

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    This is the final version of the article. Available from the publisher via the DOI in this record.There is a compelling need for accurate, low cost diagnostics to identify osteo-tissues that are associated with a high risk of fracture within an individual. To satisfy this requirement the quantification of bone characteristics such as 'bone quality' need to exceed that provided currently by densitometry. Bone mineral chemistry and microstructure can be determined from coherent x-ray scatter signatures of bone specimens. Therefore, if these signatures can be measured, in vivo, to an appropriate accuracy it should be possible by extending terms within a fracture risk model to improve fracture risk prediction.In this preliminary study we present an examination of a new x-ray diffraction technique that employs hollow annular and semi-annular beams to measure aspects of 'bone quality'. We present diffractograms obtained with our approach from ex vivo bone specimens at Mo Kα and W Kα energies. Primary data is parameterized to provide estimates of bone characteristics and to indicate the precision with which these can be determined.We acknowledge gratefully the funding provided by the UK Engineering and Physical Sciences Research Council (EPSRC) grant number EP/K020196/

    Features of childhood cancer in primary care: a population-based nested case-control study.

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    PublishedJournal ArticleResearch Support, Non-U.S. Gov'tBACKGROUND: This study investigated the risk of cancer in children with alert symptoms identified in current UK guidance, or with increased consultation frequency in primary care. METHODS: A population-based, nested case-control study used data from the General Practice Research Database. In all, 1267 children age 0-14 years diagnosed with childhood cancer were matched to 15,318 controls. Likelihood ratios and positive predictive values (PPVs) were calculated to assess risk. RESULTS: Alert symptoms recorded in the 12 and 3 months before diagnosis were present in 33.7% and 27.0% of cases vs 5.4% and 1.4% of controls, respectively. The PPV of having cancer for any alert symptom in the 3 months before diagnosis was 0.55 per 1000 children. Cases consulted more frequently particularly in the 3 months before diagnosis (86% cases vs 41% controls). Of these, 36% of cases and 9% of controls had consulted 4 times or more. The PPV for cancer in a child consulting 4 times or more in 3 months was 0.13 per 1000 children. CONCLUSION: Alert symptoms and frequent consultations are associated with childhood cancer. However, individual symptoms and consultation patterns have very low PPVs for cancer in primary care (e.g., of 10,000 children with a recorded alert symptom, approximately 6 would be diagnosed with cancer within 3 months).RMD is funded by the National Institute for Health Research (NIHR). WH was part funded by a NIHR postdoctoral fellowship. This study is based on data from the Full Feature General Practice Research Database (GPRD) obtained under licence from the UK Medicines and Healthcare Products Regulatory Agency (MHRA). However, the interpretation and conclusions contained in this study are those of the author/s alone. Access to the GPRD was funded through the Medical Research Council (MRC) licence agreement with the UK Medicines and Healthcare Products Regulatory Agency

    Sex-dependent influence of endogenous estrogen in pulmonary hypertension

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    Rationale: The incidence of pulmonary arterial hypertension (PAH) is greater in women suggesting estrogens may play a role in the disease pathogenesis. Experimentally, in males exogenously administered estrogen can protect against PH; however in models that display female susceptibility estrogens may play a causative role. Objectives: To clarify the influence of endogenous estrogen and gender in PH and assess the therapeutic potential of a clinically available aromatase inhibitor. Methods: We interrogated the effect of reduced endogenous estrogen in males and females using the aromatase inhibitor, anastrozole, in two models of PH; the hypoxic mouse and Sugen 5416/hypoxic rat. We also determined the effects of gender on pulmonary expression of aromatase in these models and in lungs from PAH patients. Results: Anastrozole attenuated PH in both models studied, but only in females. To verify this effect was due to reduced estrogenic activity we confirmed that in hypoxic mice inhibition of estrogen receptor alpha also has a therapeutic effect specifically in females. Female rodent lung displays increased aromatase and decreased BMPR2 and Id1 expression compared to male. Anastrozole treatment reversed the impaired BMPR2 pathway in females. Increased aromatase expression was also detected in female human pulmonary artery smooth muscle cells compared to male. Conclusions: The unique phenotype of female pulmonary arteries facilitates the therapeutic effects of anastrozole in experimental PH confirming a role for endogenous estrogen in the disease pathogenesis in females and suggests aromatase inhibitors may have therapeutic potential

    A cross sectional study of water quality from dental unit water lines in dental practices in the West of Scotland

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    OBJECTIVE: To determine the microbiological quality of water from dental units in a general practice setting and current practice for disinfection of units. DESIGN: A cross-sectional study of the water quality from 40 dental units in 39 general practices and a questionnaire of the disinfection protocols used in those practices. SETTING: NHS practices in primarydental care. SUBJECTS: Thirty-nine general practices from the West of Scotland. METHODS: Water samples were collected on two separate occasions from dental units and analysed for microbiological quality by the total viable count (TVC) method. Water specimens were collected from the triple syringe, high speed outlet, cup filler and surgery tap. Each participating practitioner was asked to complete a questionnaire. Results Microbial contamination was highest from the high speed outlet followed by the triple syringe and cup filler. On average, the TVC counts from the high speed water lines at 37 degrees C and for the high speed lines, triple syringe and cup filler at 22 degrees C were significantly higher than that from the control tap water specimens. The study included units from 11 different manufacturers with ages ranging from under one year to over eight years. The age of the dental unit analysed did not appear to influence the level of microbial contamination. Five of the practices surveyed used disinfectants to clean the dental units but these had no significant effect on the microbiological quality of the water. The majority of dental units (25 out of 40) were never flushed with water between patients. A number of different non-sterile irrigants were used for surgical procedures. CONCLUSION: The microbiological quality of water from dental units in general dental practice is poor compared with that from drinking water sources. Suitable sterile irrigants should be used for surgical procedures in dental practice. Further work is required for pragmatic decontamination regimens of dental unit water lines in a general dental practice setting

    Extending the applicability of the dose addition model to the assessment of chemical mixtures of partial agonists by using a novel toxic unit extrapolation method

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    This article has been made available through the Brunel Open Access Publishing Fund.Dose addition, a commonly used concept in toxicology for the prediction of chemical mixture effects, cannot readily be applied to mixtures of partial agonists with differing maximal effects. Due to its mathematical features, effect levels that exceed the maximal effect of the least efficacious compound present in the mixture, cannot be calculated. This poses problems when dealing with mixtures likely to be encountered in realistic assessment situations where chemicals often show differing maximal effects. To overcome this limitation, we developed a pragmatic solution that extrapolates the toxic units of partial agonists to effect levels beyond their maximal efficacy. We extrapolated different additivity expectations that reflect theoretically possible extremes and validated this approach with a mixture of 21 estrogenic chemicals in the E-Screen. This assay measures the proliferation of human epithelial breast cancers. We found that the dose-response curves of the estrogenic agents exhibited widely varying shapes, slopes and maximal effects, which made it necessary to extrapolate mixture responses above 14% proliferation. Our toxic unit extrapolation approach predicted all mixture responses accurately. It extends the applicability of dose addition to combinations of agents with differing saturating effects and removes an important bottleneck that has severely hampered the use of dose addition in the past. © 2014 Scholze et al

    The key role of nitric oxide in hypoxia: hypoxic vasodilation and energy supply-demand matching

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    Significance: a mismatch between energy supply and demand induces tissue hypoxia with the potential to cause cell death and organ failure. Whenever arterial oxygen concentration is reduced, increases in blood flow - 'hypoxic vasodilation' - occur in an attempt to restore oxygen supply. Nitric oxide is a major signalling and effector molecule mediating the body's response to hypoxia, given its unique characteristics of vasodilation (improving blood flow and oxygen supply) and modulation of energetic metabolism (reducing oxygen consumption and promoting utilization of alternative pathways). Recent advances: this review covers the role of oxygen in metabolism and responses to hypoxia, the hemodynamic and metabolic effects of nitric oxide, and mechanisms underlying the involvement of nitric oxide in hypoxic vasodilation. Recent insights into nitric oxide metabolism will be discussed, including the role for dietary intake of nitrate, endogenous nitrite reductases, and release of nitric oxide from storage pools. The processes through which nitric oxide levels are elevated during hypoxia are presented, namely (i) increased synthesis from nitric oxide synthases, increased reduction of nitrite to nitric oxide by heme- or pterin-based enzymes and increased release from nitric oxide stores, and (ii) reduced deactivation by mitochondrial cytochrome c oxidase. Critical issues: several reviews covered modulation of energetic metabolism by nitric oxide, while here we highlight the crucial role NO plays in achieving cardiocirculatory homeostasis during acute hypoxia through both vasodilation and metabolic suppression Future directions: we identify a key position for nitric oxide in the body's adaptation to an acute energy supply-demand mismatc
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