Scrapie surveillance in Great Britain: results of an abattoir survey, 1997/98     

Simmons MM  Ryder SJ  Chaplin MC  Spencer YI  Webb CR  Hoinville LJ  Ryan J  Stack MJ  Wells GA  Wilesmith JW 《The Veterinary record》2000,146(14):391-395

A randomised sample of 2,809 apparently healthy sheep, 55 per cent of them less than 15 months of age, which were slaughtered for human consumption at abattoirs in Great Britain in 1997/98, was taken to establish the prevalence of scrapie infection. The medulla oblongata of each sheep was examined histopathologically at the level of the obex, and fresh brain tissue was examined for scrapie-associated fibrils (SAF) to establish whether there was evidence of scrapie. In addition, histological sections of the medulla from 500 of the sheep were immunostained with an antiserum to PrP, and the same technique was also applied to any animal found positive or inconclusive by the histological or SAF examinations. Any sheep which was positive by any of these diagnostic methods was also examined by Western immunoblotting, for the detection of the disease-specific protein PrP(Sc). A total of 2,798 sheep (99.6 per cent) were negative by all the methods applied. Ten animals were SAF-positive but negative by all the other methods, and in one animal there was immunohistochemical staining which could not be interpreted unequivocally as disease-specific. A mathematical model was used to estimate the prevalence of scrapie infection in the national slaughtered sheep population which would be consistent with these results. By this model, the absence of unequivocally substantiated cases of scrapie in the sample was consistent with a prevalence of infection in the slaughter population of up to 11 per cent.  相似文献   

牦牛大肠埃希氏菌病灭活疫苗的制备     

曾群辉  朱国玉  索朗斯珠  旦巴次仁  布旺堆 《中国兽药杂志》2007,41(9):24-26

用本实验室分离鉴定的致病性牦牛大肠埃希氏菌，按常规方法制备了4批氢氧化铝胶灭活疫苗。对牦牛大肠埃希氏菌的菌液培养、纯粹检验、活菌计数、灭活等进行了探索，并对用该菌研制成的疫苗进行了常规检验。结果4批灭活疫苗经无菌检验为阴性；经物理性状检验为：静置后上层是淡黄色的澄明液体，下层为灰白色沉淀，振荡后呈均匀混浊液；经牦牛安全检验结果为安全；经牦牛效力试验有效。牦牛大肠埃希氏菌病灭活疫苗为免疫预防该病打下了良好的基础。  相似文献   

Leo K Bustad     

Richard Mordaunt Webb 《Australian veterinary journal》1998,76(12):812-812

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Development of buffer methods and evaluation of pedotransfer functions to estimate pH buffer capacity of highly weathered soils     

M. T. F. Wong  M. J. Webb  K. Wittwer 《Soil Use and Management》2013,29(1):30-38

The pH buffer capacity of a soil (pHBC) determines the amount of lime required to raise the pH of the soil layer from its initial acid condition to an optimal pH for plant growth and the time available under current net acid addition rate (NAAR) until the soil layer acidifies to a critical pH leading to likely production losses. Accurate values of pHBC can also be used to calculate NAAR from observed changes in soil pH. In spite of its importance, there is a critical shortage of pHBC data, likely due to the long period of time needed for its direct measurement. This work aimed to develop quick, simple and reliable methods of pHBC measurement and to test these methods against a slow (7‐day) titration used as benchmark. The method developed here calculates pHBC directly from the pH buffer capacity of the buffer solution and the increase in soil pH and corresponding decrease in pH of the buffer solution following mixing and equilibration. The pHBC values calculated using Adams and Evans or modified Woodruff buffers were in accord with those measured by slow titration. Buffer methods are easily deployed in commercial and research laboratories as well as in the field. The advantage of using buffer solutions to calculate pHBC instead of lime requirement is the broad application of this soil property. The pHBC of a soil is an intrinsic property that would not be expected to need remeasurement over periods of less than decades. Recurring lime requirement can be calculated from the soil's pHBC, initial and target pH values. A large proportion of the variability in pHBC was explained by the soil organic carbon content. This relationship between pHBC and soil organic carbon content allowed us to develop local pedotransfer functions to estimate pHBC for different regions of Australia.  相似文献   

Identification of interleukin-1 in equine osteoarthritic joint effusions   总被引：1，自引：0，他引：1  

E A Morris  B S McDonald  A C Webb  L J Rosenwasser 《American journal of veterinary research》1990,51(1):59-64

Interleukin-1 (IL-1) is a protein secreted by stimulated cells of the monocyte-macrophage line, which has a number of important biologic activities. Interleukin-1 has been implicated in the induction and augmentation of the pathologic processes involved in arthritis and articular cartilage destruction. Horses develop osteoarthritis with a frequency and degree of severity similar to human beings. To further document the similarity of the osteoarthritic process in people and horses, the synovial fluid from 5 horses with clinical osteoarthritis was tested for IL-1 bioactivity. Interleukin-1 activity was found in all tested synovial fluids. Upon column chromatography, the synovial fluid-derived factor had a molecular weight consistent with that of IL-1 in other mammalian species. Ion exchange chromatography of osteoarthritic synovial fluid revealed the principal peaks of bioactivity to be in the fractions with isoelectric points of 7.2, 5.4, and 4.7, which are characteristic of IL-1. A considerable degree of homology between human and equine IL-1 was demonstrated by the cross hybridization of human IL-1 beta cDNA probe with RNA derived from IL-1-producing equine adherent monocytes. These results indicate that equine IL-1 is in all of the osteoarthritic equine joints tested and that equine IL-1 has many of the characteristics of IL-1 isolated from other species.  相似文献   

Vitamin A deficiency: serum cortisol and humoral immunity in lambs   总被引：1，自引：0，他引：1  

N J Bruns  K E Webb 《Journal of animal science》1990,68(2):454-459

Serum cortisol and antigen-specific and polyclonal immunoglobulin G (IgG) concentrations were measured to investigate the relationship between vitamin A status and immune function in lambs. Twenty-four 3-mo-old crossbred ewe lambs weighing approximately 10 kg were each fed 900 g/d of a carotene-deficient diet. The 12 control lambs also received a 100,000 IU oral dose of vitamin A palmitate every 2 wk. All lambs were given primary and secondary antigenic challenges. Lambs were slaughtered at the end of the secondary challenge period. Liver vitamin A concentrations were greater (P less than .001) in the control animals (69.5 vs 1.3 micrograms/g wet tissue). Both groups of lambs exhibited a similar growth response until d 105, after which daily gain of the control lambs exceeded (P less than .03) that of the A-deficient lambs. Polyclonal serum IgG concentrations were greater (P less than .05) in the A-deficient lambs on d 49 to 124 and on d 151 (P less than .10). Ovalbumin-specific serum IgG concentrations tended to be greater in the control lambs throughout the primary and secondary challenge periods. Control lambs had greater titers on d 164 (P less than .07) and d 190 (P less than .03). Vitamin A status appeared to have no consistent effects on serum cortisol concentrations. Spleen weights were greater (P less than .002) in the A-deficient lambs. Lungs from 11 of 12 A-deficient lambs contained abscesses, as opposed to 1 of 12 for the control lambs. Both polyclonal and antigen-specific IgG concentrations were affected by vitamin A status. Serum cortisol concentrations did not appear to mediate this effect.  相似文献   

Storage protein changes during zygotic embryogenesis in interior spruce     

Flinn BS  Roberts DR  Webb DT  Sutton BC 《Tree physiology》1991,8(1):71-81

The major storage proteins isolated from protein bodies of embryo tissues of interior spruce Picea glauca (Moench) Voss/Picea engelmanii Parry had apparent molecular weights of 41, 35, 33, 24 and 22 kD. Minor proteins of 30 and 27.5 kD were also observed. Based on their solubility characteristics, the 41 kD protein was identified as a water and buffer-soluble albumin, and the 35, 33, 24 and 22 kD proteins were characterized as buffer-insoluble, high salt-soluble globulins. Two-dimensional electrophoresis revealed each protein was composed of several isoelectric variants. Developmentally specific accumulation of storage proteins was observed during embryogenesis. The 41 kD protein only accumulated during the later stages of cotyledon maturation, whereas the other storage proteins began to accumulate during the early stages of embryo development. All storage proteins showed major accumulations during cotyledon maturation.  相似文献   

评估调质时间和温度对猪颗粒饲料淀粉糊化度和维生素沉积的影响     

Lewis LL  Stark CR  Fahrenholz AC  Bergstrom JR  Jones CK 《广东饲料》2015,24(5)

本论文研究了饲料加工的两个关键参数(调质温度和时间)对育肥猪颗粒饲料淀粉糊化度和维生素沉积的影响。日粮配方为含30%干酒糟及其可溶物的玉米-豆粕型基础日粮。整个试验中配方保持不变。本试验采用2×3双因子设计,调质温度分别为77℃和88℃,调质时间分别15秒、30秒和60秒。此外,本试验还设置一个对照组,对照组饲料不采用调质制粒工艺,而是采用粉料饲喂。因此,本试验共有7个处理组。采集调质后制粒前(热干粉)、制粒后冷却前(热制粒)、以及制粒冷却后(冷制粒)的样品,并分析这三种样品的总淀粉率、淀粉糊化  相似文献   

What is your diagnosis? Cytogram triple threat          下载免费PDF全文

Julie L. Webb 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2015,44(3):461-462

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What is your diagnosis? Granules galore!          下载免费PDF全文

Saundra Sample  Julie L. Webb  Melissa Behr  Kai‐Biu Shiu 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2015,44(1):165-166

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