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A pilot study was undertaken to assess the stability of canine factor VIII:coagulant (FVIII:C) activity over three days, under various storage conditions (plasma at 4, 20 and 37 degrees C, whole blood at 4 and 20 degrees C). Blood collected from normal and hemophiliac dogs was used. Both plasma and whole blood samples appeared to be stable for up to 48 h at 4 and 20 degrees C. A subsequent study evaluated FVIII:C stability at 4 and 20 degrees C when stored as whole blood only. Samples were tested at 0, 24 and 48 h after collection. At 4 degree C there was a significant decline at 24 h (p less than 0.05), from 110% to 97% (mean values). Although the mean value was further decreased at 48 h (89%) this was not significant (p greater than 0.05). No significant change in FVIII:C activity was observed in whole blood stored at 20 degrees C for 24 or 48 h (110% and 107% respectively). These results suggest that canine whole blood samples collected into sodium citrate stored at 20 degrees C are adequate for routine FVIII:C assay for up to 48 h after collection.  相似文献   
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Infections by the gill fluke Zeuxapta seriolae are a serious concern for sea cage aquaculture of kingfish, Seriola lalandi. The present study aimed to determine the pathophysiological effects of a progressive infection with Z. seriolae and the effects of treatment with hydrogen peroxide. For the progression of infection study, infected fish were taken from a sea cage farm, treated to remove parasites and then infected by cohabitation with heavily infected fish. Samples were taken at 2-week intervals for 8 weeks. Infection intensity peaked at 4 weeks post-infection (mean intensity 565.9) and the number of mature worms (2 mm fixed length or larger) peaked at 6 weeks post-infection. Attachment of Z. seriolae appeared to cause little localized pathology; however, the occurrence of hyperplastic lamellae increased as the infection progressed. Haemoglobin concentrations were negatively correlated with Z. seriolae intensity and were lower than controls at 4 weeks (35.8% decrease) and 6 weeks (57.4% decrease) post-infection. Blood lactate concentration and plasma osmolality increased throughout the course of infection. For the effect of treatment experiment, groups of infected and non-infected fish were sampled either before or after treatment with hydrogen peroxide. Treated fish from both infected and uninfected groups had increased plasma lactate, osmolality and pH compared with pre-treatment groups. Treatment with hydrogen peroxide appeared to have acute effects on fish health but the magnitude (e.g. lactate, osmolality) and extent of the effects (e.g. haemoglobin) was much less than that caused by chronic infection with Z. seriolae.  相似文献   
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Bovine tuberculosis (BTB) is an important livestock disease, seriously impacting cattle industries in both industrialised and pre-industrialised countries. Like TB in other mammals, infection is life long and, if undiagnosed, may progress to disease years after exposure. The risk of disease in humans is highly age-dependent, however in cattle, age-dependent risks have yet to be quantified, largely due to insufficient data and limited diagnostics. Here, we estimate age-specific reactor rates in Great Britain by combining herd-level testing data with spatial movement data from the Cattle Tracing System (CTS). Using a catalytic model, we find strong age dependencies in infection risk and that the probability of detecting infection increases with age. Between 2004 and 2009, infection incidence in cattle fluctuated around 1%. Age-specific incidence increased monotonically until 24–36 months, with cattle aged between 12 and 36 months experiencing the highest rates of infection. Beef and dairy cattle under 24 months experienced similar infection risks, however major differences occurred in older ages. The average reproductive number in cattle was greater than 1 for the years 2004–2009. These methods reveal a consistent pattern of BTB rates with age, across different population structures and testing patterns. The results provide practical insights into BTB epidemiology and control, suggesting that targeting a mass control programme at cattle between 12 and 36 months could be beneficial.  相似文献   
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Gas-liquid scattering experiments provide direct observations of the fate of hydrogen-bonding molecules striking the surfaces of acidic liquids. Collisions of gaseous formic acid with concentrated sulfuric acid show that impinging monomers (HCOOH and DCOOD) scatter inelastically from the interface or become trapped by surface H2SO4. Most trapped DCOOD molecules undergo proton exchange before desorbing from the acid, indicating that gas-surface accommodation almost always leads to reaction with H2SO4 molecules. This proton transfer is not inhibited by dimerization of the formic acid: The dimers readily undergo intramolecular hydrogen bond cleavage and D-H exchange before desorbing from the acid.  相似文献   
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