1,726 research outputs found

    Pruritus is a common feature in sheep infected with the BSE agent.

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    BACKGROUND: The variability in the clinical or pathological presentation of transmissible spongiform encephalopathies (TSEs) in sheep, such as scrapie and bovine spongiform encephalopathy (BSE), has been attributed to prion protein genotype, strain, breed, clinical duration, dose, route and type of inoculum and the age at infection. The study aimed to describe the clinical signs in sheep infected with the BSE agent throughout its clinical course to determine whether the clinical signs were as variable as described for classical scrapie in sheep. The clinical signs were compared to BSE-negative sheep to assess if disease-specific clinical markers exist. RESULTS: Forty-seven (34%) of 139 sheep, which comprised 123 challenged sheep and 16 undosed controls, were positive for BSE. Affected sheep belonged to five different breeds and three different genotypes (ARQ/ARQ, VRQ/VRQ and AHQ/AHQ). None of the controls or BSE exposed sheep with ARR alleles were positive. Pruritus was present in 41 (87%) BSE positive sheep; the remaining six were judged to be pre-clinically infected. Testing of the response to scratching along the dorsum of a sheep proved to be a good indicator of clinical disease with a test sensitivity of 85% and specificity of 98% and usually coincided with weight loss. Clinical signs that were displayed significantly earlier in BSE positive cases compared to negative cases were behavioural changes, pruritic behaviour, a positive scratch test, alopecia, skin lesions, teeth grinding, tremor, ataxia, loss of weight and loss of body condition. The frequency and severity of each specific clinical sign usually increased with the progression of disease over a period of 16-20 weeks. CONCLUSION: Our results suggest that BSE in sheep presents with relatively uniform clinical signs, with pruritus of increased severity and abnormalities in behaviour or movement as the disease progressed. Based on the studied sheep, these clinical features appear to be independent of breed, affected genotype, dose, route of inoculation and whether BSE was passed into sheep from cattle or from other sheep, suggesting that the clinical phenotype of BSE is influenced by the TSE strain more than by other factors. The clinical phenotype of BSE in the genotypes and breed studied was indistinguishable from that described for classical scrapie cases

    Experimental sheep BSE prions generate the vCJD phenotype when serially passaged in transgenic mice expressing human prion protein

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    The epizootic prion disease of cattle, bovine spongiform encephalopathy (BSE), causes variant Creutzfeldt-Jakob disease (vCJD) in humans following dietary exposure. While it is assumed that all cases of vCJD attributed to a dietary aetiology are related to cattle BSE, sheep and goats are susceptible to experimental oral challenge with cattle BSE prions and farmed animals in the UK were undoubtedly exposed to BSE-contaminated meat and bone meal during the late 1980s and early 1990s. Although no natural field cases of sheep BSE have been identified, it cannot be excluded that some BSE-infected sheep might have entered the European human food chain. Evaluation of the zoonotic potential of sheep BSE prions has been addressed by examining the transmission properties of experimental brain isolates in transgenic mice that express human prion protein, however to-date there have been relatively few studies. Here we report that serial passage of experimental sheep BSE prions in transgenic mice expressing human prion protein with methionine at residue 129 produces the vCJD phenotype that mirrors that seen when the same mice are challenged with vCJD prions from patient brain. These findings are congruent with those reported previously by another laboratory, and thereby strongly reinforce the view that sheep BSE prions could have acted as a causal agent of vCJD within Europe

    Towards a broad-based and holistic framework of sustainable intensification indicators

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    The concept of 'Sustainable Intensification' (SI) has been promoted as a potential solution to the many contemporary challenges facing agriculture, but has also received widespread criticism for being too narrow in scope and failing to address all aspects of sustainability. Despite this, there are few suggestions in the literature as to what a holistic, broad-based approach to SI should comprise and what issues and trade-offs are likely to arise in the adoption and operation of such a broadly-based approach. We report a suit of SI indicators suggested by UK stakeholders, evaluate the plausibility of these in terms of the commonly established principles of sustainability, and identify the critical issues that may arise in the adoption and operation of these indicators. The purpose of this paper is not to recommend a specific blueprint for SI but to raise issues and questions for dialogue amongst stakeholders. Data were collected via semi-structured interviews with 32 stakeholders from throughout the UK agrifood system. The data were analysed thematically and organised using a Social-Ecological Systems (SESs) framework. The interviewees suggested a total of 110 SI indicators, of which the most frequently suggested related to agricultural production and ecological considerations. There was less emphasis placed on social and cultural dimensions of agricultural systems. A number of the indicators suggested were poorly-defined and it was difficult to determine what particular aspects of sustainability they addressed. Many potential trade-offs between the indicators were also evident. The findings raise a number of questions. Is it appropriate to continue referring to SI as Sustainable Intensification when it fails to give equal consideration to all accepted aspects of sustainability? Would it be more appropriate to refer to the SI concept as 'Ecological Intensification'? Is a broad-based and all-encompassing definition of 'sustainability' always desirable, or should 'sustainability' be considered as context specific, with the weighting of the different dimensions varying according to operational circumstances? We argue that these questions need to be resolved through stakeholder dialogues in order for the concept of SI to become more widely accepted and implementable in practice

    Molecular, morphological and acoustic identification of Eumops maurus and Eumops hansae (Chiroptera: Molossidae) with new reports from Central Amazonia

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    Eumops maurus and Eumops hansae are rarely captured Neotropical molossid bats for which information on taxonomy, natural history, and spatial distribution are scarce. This translates into a poor understanding of their ecology and limits the delimitation of useful characters for their identification. Here, we describe records of these two molossids from the Central Brazilian Amazon, providing data on their external and craniodental morphology, DNA barcode (COI) sequences complemented by acoustic data for the species. Morphological characters, DNA sequence data and phylogenetic relationships within the genus Eumops were consistent with those previously described for both species. Echolocation call characteristics did not differ significantly so as to be useful for separating E. maurus and E. hansae from other congeners. Our records are, respectively the first and the second for Central Amazonia as one individual previously attributed to Eumops amazonicus from Manaus may be considered a junior synonym for E. hansae. These new records increase the extent of the species’ known ranges, partially filling in previous existing gaps in their distribution in central South America. Our data further suggest that these molossid bats forage in a wider range of habitats than previously thought

    Diffusion tensor imaging of Parkinson's disease, multiple system atrophy and progressive supranuclear palsy: a tract-based spatial statistics study

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    Although often clinically indistinguishable in the early stages, Parkinson's disease (PD), Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP) have distinct neuropathological changes. The aim of the current study was to identify white matter tract neurodegeneration characteristic of each of the three syndromes. Tract-based spatial statistics (TBSS) was used to perform a whole-brain automated analysis of diffusion tensor imaging (DTI) data to compare differences in fractional anisotropy (FA) and mean diffusivity (MD) between the three clinical groups and healthy control subjects. Further analyses were conducted to assess the relationship between these putative indices of white matter microstructure and clinical measures of disease severity and symptoms. In PSP, relative to controls, changes in DTI indices consistent with white matter tract degeneration were identified in the corpus callosum, corona radiata, corticospinal tract, superior longitudinal fasciculus, anterior thalamic radiation, superior cerebellar peduncle, medial lemniscus, retrolenticular and anterior limb of the internal capsule, cerebral peduncle and external capsule bilaterally, as well as the left posterior limb of the internal capsule and the right posterior thalamic radiation. MSA patients also displayed differences in the body of the corpus callosum corticospinal tract, cerebellar peduncle, medial lemniscus, anterior and superior corona radiata, posterior limb of the internal capsule external capsule and cerebral peduncle bilaterally, as well as the left anterior limb of the internal capsule and the left anterior thalamic radiation. No significant white matter abnormalities were observed in the PD group. Across groups, MD correlated positively with disease severity in all major white matter tracts. These results show widespread changes in white matter tracts in both PSP and MSA patients, even at a mid-point in the disease process, which are not found in patients with PD

    Environmental Costs of Government-Sponsored Agrarian Settlements in Brazilian Amazonia

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    Brazil has presided over the most comprehensive agrarian reform frontier colonization program on Earth, in which ~1.2 million settlers have been translocated by successive governments since the 1970's, mostly into forested hinterlands of Brazilian Amazonia. These settlements encompass 5.3% of this ~5 million km2 region, but have contributed with 13.5% of all land conversion into agropastoral land uses. The Brazilian Federal Agrarian Agency (INCRA) has repeatedly claimed that deforestation in these areas largely predates the sanctioned arrival of new settlers. Here, we quantify rates of natural vegetation conversion across 1911 agrarian settlements allocated to 568 Amazonian counties and compare fire incidence and deforestation rates before and after the official occupation of settlements by migrant farmers. The timing and spatial distribution of deforestation and fires in our analysis provides irrefutable chronological and spatially explicit evidence of agropastoral conversion both inside and immediately outside agrarian settlements over the last decade. Deforestation rates are strongly related to local human population density and road access to regional markets. Agrarian settlements consistently accelerated rates of deforestation and fires, compared to neighboring areas outside settlements, but within the same counties. Relocated smallholders allocated to forest areas undoubtedly operate as pivotal agents of deforestation, and most of the forest clearance occurs in the aftermath of government-induced migration

    Why the fair innings argument is not persuasive

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    The fair innings argument (FIA) is frequently put forward as a justification for denying elderly patients treatment when they are in competition with younger patients and resources are scarce. In this paper I will examine some arguments that are used to support the FIA. My conclusion will be that they do not stand up to scrutiny and therefore, the FIA should not be used to justify the denial of treatment to elderly patients, or to support rationing of health care by age. There are six issues arising out of the FIA which are to be addressed. First, the implication that there is such a thing as a fair share of life. Second, whether it makes sense to talk of a fair share of resources in the context of health care and the FIA. Third, that 'fairness' is usually only mentioned with regard to the length of a person's life, and not to any other aspect of it. Fourth, if it is sensible to discuss the merits of the FIA without taking account of the 'all other things being equal' argument. Fifth, the difference between what is unfair and what is unfortunate. Finally, that it is tragic if a young person dies, but only unfortunate if an elderly person does

    On staying grounded and avoiding Quixotic dead ends

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    The 15 articles in this special issue on The Representation of Concepts illustrate the rich variety of theoretical positions and supporting research that characterize the area. Although much agreement exists among contributors, much disagreement exists as well, especially about the roles of grounding and abstraction in conceptual processing. I first review theoretical approaches raised in these articles that I believe are Quixotic dead ends, namely, approaches that are principled and inspired but likely to fail. In the process, I review various theories of amodal symbols, their distortions of grounded theories, and fallacies in the evidence used to support them. Incorporating further contributions across articles, I then sketch a theoretical approach that I believe is likely to be successful, which includes grounding, abstraction, flexibility, explaining classic conceptual phenomena, and making contact with real-world situations. This account further proposes that (1) a key element of grounding is neural reuse, (2) abstraction takes the forms of multimodal compression, distilled abstraction, and distributed linguistic representation (but not amodal symbols), and (3) flexible context-dependent representations are a hallmark of conceptual processing

    Dijet signals of the Little Higgs model with T-parity

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    The Littest Higgs model with T-parity (LHT), apart from offering a viable solution to the naturalness problem of the Standard Model, also predicts a set of new fermions as well as a candidate for dark matter. We explore the possibility of discovering the heavy T-odd quark Q_H at the LHC in a final state comprising two hard jets with a large missing transverse momentum. Also discussed is the role of heavy flavor tagging.Comment: Changes in text. Some references adde

    Decreased startle modulation during anticipation in the postpartum period in comparison to late pregnancy

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    Knowledge about healthy women’s psychophysiological adaptations during the large neuroendocrine changes of pregnancy and childbirth is essential in order to understand why these events have the potential to disrupt mental health in vulnerable individuals. This study aimed to compare startle response modulation, an objective psychophysiological measure demonstrated to be influenced by anxiety and depression, longitudinally across late pregnancy and the postpartum period. The acoustic startle response modulation was assessed during anticipation of affective images and during image viewing in 31 healthy women during gestational weeks 36–39 and again at 4 to 6 weeks postpartum. No startle modulation by affective images was observed at either time point. Significant modulation during anticipation stimuli was found at pregnancy assessment but was reduced in the postpartum period. The women rated the unpleasant images more negative and more arousing and the pleasant images more positive at the postpartum assessment. Self-reported anxiety and depressive symptoms did not change between assessments. The observed postpartum decrease in modulation of startle by anticipation suggests a relatively deactivated defense system in the postpartum period
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