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41.
Musculo-skeletal diseases are a major cause of pain and suffering in cats and several conditions involve increased bone resorption by osteoclasts. However, little is known about the biology of these cells in the cat. In this study we established a method to generate feline osteoclasts from blood mononuclear cells stimulated by macrophage colony stimulating factor (M-CSF) and receptor activator of NF-kappaB ligand (RANKL). Cultured osteoclasts are multinucleated, express tartrate resistant acid phosphatase (TRAP), form F-actin rings and resorb bone. They express alpha(v)beta3 vitronectin receptor and osteoclast enzymes, cathepsin K and MMP9; the myeloid antigen, CD18, and the megakaryocyte/platelet integrin, CD41, are absent. This phenotype is typical of osteoclasts from other species. Three resorption inhibitors were examined for activity against feline osteoclasts. Calcitonin, bisphosphonate and RGD integrin inhibitory peptide all reduced bone resorption at doses similar to those efficacious in rabbit or human. We conclude that blood-derived osteoclast cultures are a suitable in vitro system for assessing the ability of drugs to inhibit bone resorption in domestic cats.  相似文献   
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At present, collective action regarding bio-security among UK cattle and sheep farmers is rare. Despite the occurrence of catastrophic livestock diseases such as bovine spongiform encephalopathy (BSE) and foot and mouth disease (FMD), within recent decades, there are few national or local farmer-led animal health schemes. To explore the reasons for this apparent lack of interest, we utilised a socio-psychological approach to disaggregate the cognitive, emotive and contextual factors driving bio-security behaviour among cattle and sheep farmers in the United Kingdom (UK). In total, we interviewed 121 farmers in South-West England and Wales. The main analytical tools included a content, cluster and logistic regression analysis.The results of the content analysis illustrated apparent ‘dissonance’ between bio-security attitudes and behaviour.1 Despite the heavy toll animal disease has taken on the agricultural economy, most study participants were dismissive of the many measures associated with bio-security. Justification for this lack of interest was largely framed in relation to the collective attribution or blame for the disease threats themselves. Indeed, epidemic diseases were largely related to external actors and agents. Reasons for outbreaks included inadequate border control, in tandem with ineffective policies and regulations. Conversely, endemic livestock disease was viewed as a problem for ‘bad’ farmers and not an issue for those individuals who managed their stock well. As such, there was little utility in forming groups to address what was largely perceived as an individual problem.Further, we found that attitudes toward bio-security did not appear to be influenced by any particular source of information per se. While strong negative attitudes were found toward specific sources of bio-security information, e.g. government leaflets, these appear to simply reflect widely held beliefs. In relation to actual bio-security behaviours, the logistic regression analysis revealed no significant difference between in-scheme and out of scheme farmers.We concluded that in order to support collective action with regard to bio-security, messages need to be reframed and delivered from a neutral source. Efforts to support group formation must also recognise and address the issues relating to perceptions of social connectedness among the communities involved.  相似文献   
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Constraints to the introduction of enhanced biosecurity systems are rarely considered in sufficient detail when population medicine specialists initiate new control schemes. The main objective of our research was to investigate and compare the different attitudes constraining improvement in biosecurity for cattle and sheep farmers, practising veterinary surgeons and the auxiliary industries in Great Britain (GB). This study was carried out utilizing farmer focus groups, a questionnaire survey of veterinary practitioners and a telephone survey of auxiliary industry representatives. It appears that farmers and veterinarians have their own relatively clear definitions for biosecurity in relation to some major diseases threatening GB agriculture. Overall, farmers believe that other stakeholders, such as the government, should make a greater contribution towards biosecurity within GB. Conversely, veterinary practitioners saw their clients’ ability or willingness to invest in biosecurity measures as a major constraint. Veterinary practitioners also felt that there was need for additional proof of efficacy and/or the potential economic benefits of proposed farm biosecurity practices better demonstrated. Auxiliary industries, in general, were not certain of their role in biosecurity although study participants highlighted zoonoses as part of the issue and offered that most of the constraints operated at farm level.  相似文献   
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In the early 1990s, the spawning biomass of the southern bluefin tuna (SBT) population was estimated to be less than 10% of its historical level. However, major uncertainties surrounding the age composition of the catch confounded the virtual population analysis assessment models. To eliminate these uncertainties, validated estimates of the age composition of the catch were required.We examined scales, caudal vertebrae and sagittal otoliths to determine which structure produced the most accurate age estimates in SBT. Scales proved useful for estimating ages of SBT only up to 4 years. Marginal increment analysis verified that the zones of dense circuli visible on the scales were deposited annually up to this age. In larger fish, the compression of circuli on the margin of scales and high incidence of regenerated scales made estimation of age very difficult. Obvious increments were present on both the vertebrae and otoliths. Age estimates from the two structures matched closely for the first 10 years of life. However, in larger (older) fish the counts diverged, otoliths consistently providing higher age estimates. We determined that annual increments are formed on sagittal otoliths throughout life but that this is not the case in vertebrae, where bands are formed less frequently. Thus, vertebrae were unreliable for estimating age beyond 10 years, which corresponds approximately to the age-at-first maturity.Ages were estimated from otoliths of 1121 fish from throughout the species’ size range. These data indicate that SBT live to at least 40 years of age, twice the longevity previously accepted; that age at recruitment is 1 year, not 2; and that mean age-at-maturity is approximately 11 years, not 7.The age distribution of SBT catches by the Japanese longline fishery in the Tasman Sea indicate that a significant proportion of the SBT population in this area is over 25 years of age and that cohorts spawned in the late 1970s and early 1980s are markedly under-represented in the population. The latter is thought to result from intense exploitation on these cohorts by the Australian surface fishery soon after recruitment.  相似文献   
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The Peary caribou Rangifer tarandus pearyi is an unique subspecies confined almost entirely to the Canadian Arctic Archipelago. The decline of the population by 89% on the western Queen Elizabeth Islands between 1961 and 1974 has continued until at least 1977. The decline was principally caused by climatic changes but Peary caribou are potentially under additional pressure from hunting and disturbances associated with increasing industrial activities. We believe there are only 10–15,000 Peary caribou in Canada, and the subspieces was classified as ‘Threatened’ in 1979. The population dynamics of Peary caribou are unique among North American ungulates because weather, especially winter weather, dominates not only the reproductive rate but also recruitment and adult survival. The inter-island movements are a significant adaptation not only to sparse ranges and snow conditions, but also to recolonisation of islands that periodically, through a series of severe winters, lose their caribou.  相似文献   
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The transverse sectional area (TSA) of m. semitendinosus grows at a greater rate than the 2/3 power of liveweight in both Greyhounds and Thoroughbreds (athletic animals) while it increases at a rate proportional to liveweight in other breeds of dogs and horses (non-athletes). Although the TSA of the muscle in the adult athletes of both species is greater than that of the less fortunate fellow specific members there is no significant difference in the TSA of the muscle between the perinates of the two types of animals within each species. Thoroughbred cross horses have TSA values similar to those of Thoroughbreds.  相似文献   
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