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排序方式: 共有247条查询结果,搜索用时 15 毫秒
81.
82.
A device capable of testing the nociceptive threshold to mechanical stimuli has been developed for use in horses. It was operated by compressed gas and was designed so that the part attached to the horse was semi disposable. The stimulus was applied via a 2mm diameter blunt ended pin and had a number of safety features incorporated in the design to ensure that the maximum force applied was 27 newtons. The device has been used to assess the response to detomidine in a group of thoroughbreds and has proved reliable and robust in use. 相似文献
83.
Regional variations in percutaneous absorption of methimazole: an in vitro study on cat skin
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K. E. Hill J. P. Chambers B. R. Jones C. F. Bolwell D. Aberdein P. C. Mills 《Journal of veterinary pharmacology and therapeutics》2015,38(6):616-618
The use of transdermal gel medications in cats has become popular in veterinary medicine due to the ease of administration compared to oral medication. The research to support systemic absorption of drugs after transdermal gel administration and the preferred skin region to apply these drugs in cats is limited. The aim of this study was to characterize the effect of different skin regions on the percutaneous absorption pharmacokinetics of a commercially available transdermal methimazole after a finite dose was applied to feline skin in vitro. A commercial formulation of methimazole (10 mg) was applied to four skin regions (the inner stratum corneum of the ear, groin, neck, and thorax regions) from six cats. The receptor medium was sampled up to 36 h postapplication, and methimazole concentrations were measured using high‐performance liquid chromatography. Methimazole was absorbed more completely across the pinnal skin, compared to the groin, neck, and thorax (P < 0.001), which justifies application to the pinna to maximize efficacy and also to minimize the effects of grooming. 相似文献
84.
Molecular coupling of Xist regulation and pluripotency 总被引:2,自引:0,他引:2
Navarro P Chambers I Karwacki-Neisius V Chureau C Morey C Rougeulle C Avner P 《Science (New York, N.Y.)》2008,321(5896):1693-1695
During mouse embryogenesis, reversion of imprinted X chromosome inactivation in the pluripotent inner cell mass of the female blastocyst is initiated by the repression of Xist from the paternal X chromosome. Here we report that key factors supporting pluripotency-Nanog, Oct3/4, and Sox2-bind within Xist intron 1 in undifferentiated embryonic stem (ES) cells. Whereas Nanog null ES cells display a reversible and moderate up-regulation of Xist in the absence of any apparent modification of Oct3/4 and Sox2 binding, the drastic release of all three factors from Xist intron 1 triggers rapid ectopic accumulation of Xist RNA. We conclude that the three main genetic factors underlying pluripotency cooperate to repress Xist and thus couple X inactivation reprogramming to the control of pluripotency during embryogenesis. 相似文献
85.
Wirgin I Roy NK Loftus M Chambers RC Franks DG Hahn ME 《Science (New York, N.Y.)》2011,331(6022):1322-1325
The mechanistic basis of resistance of vertebrate populations to contaminants, including Atlantic tomcod from the Hudson River (HR) to polychlorinated biphenyls (PCBs), is unknown. HR tomcod exhibited variants in the aryl hydrocarbon receptor 2 (AHR2) that were nearly absent elsewhere. In ligand-binding assays, AHR2-1 protein (common in the HR) was impaired as compared to widespread AHR2-2 in binding TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and in driving expression in reporter gene assays in AHR-deficient cells treated with TCDD or PCB126. We identified a six-base deletion in AHR2 as the basis of resistance and suggest that the HR population has undergone rapid evolution, probably due to contaminant exposure. This mechanistic basis of resistance in a vertebrate population provides evidence of evolutionary change due to selective pressure at a single locus. 相似文献
86.
Vesna Furtula Johnny Liu Patricia Chambers Heather Osachoff Chris Kennedy Joanne Harkness 《Water, air, and soil pollution》2012,223(3):1017-1031
This study assessed the efficiency of sewage treatment plants (STPs) in removing sterols based on chemical analyses of both
influents and effluents. Samples from 3s and three tertiary plants were collected and analyzed by gas chromatography mass
spectrometry for 23 individual sterols including mestranol, norethindrone, equol, estrone, equilin, norgestrel, 17α-ethinylestradiol,
17α-estradiol, 17β-estradiol, estriol, dihydrocholesterol (cholestanol), coprostanol, epicoprostanol, cholesterol, desmosterol,
campesterol, stigmasterol, β-sitosterol, coprostanone, cholestanone, epicholestanol, stigmastanol, and 24-ethylcoprostanol.
The percentage of sterols remaining in effluent samples (compared to influent samples) ranged from 0% to 80% and varied among
sterol compounds and with STP location and treatment type. Differences in the efficiency of sterol removal for secondary and
tertiary STPs were statistically significant. Although the concentration of sterol compounds differed between influents and
effluents, sterol abundances remained the same. The most abundant sterol detected was cholesterol, followed by the fecal sterol
coprostanol, and the plant sterols 24-ethylcoprostanol and β-sitosterol. For three STPs, the hormone estrone was detected
in effluents at concentrations of 0.03–0.05 μg L−1. Ten sterol ratios specific for human fecal contamination and eight sterol ratios for differentiating among multiple sources
of fecal contamination were calculated and showed that 12 ratios for influent and nine ratios for effluent were successful
for human fecal source tracking. Based on sterol ratio values in this study, new criteria for identification of human fecal
contamination were suggested. 相似文献
87.
88.
Vordermeier HM Chambers MA Buddle BM Pollock JM Hewinson RG 《Veterinary journal (London, England : 1997)》2006,171(2):229-244
The sharp rise of bovine tuberculosis (TB) in Great Britain and the continuing problem of wild life reservoirs in countries such as New Zealand and Great Britain have resulted in increased research efforts into the disease. Two of the goals of this research are to develop (1) cattle vaccines against TB and (2) associated diagnostic reagents that can differentiate between vaccinated and infected animals (differential diagnosis). This review summarises recent progress and describes efforts to increase the protective efficacy of the only potential TB vaccine currently available, Mycobacterium bovis BCG, and to develop specific reagents for differential diagnosis. Vaccination strategies based on DNA or protein subunit vaccination, vaccination with live viral vectors as well as heterologous prime-boost scenarios are discussed. In addition, we outline results from studies aimed at developing diagnostic reagents to allow the distinction of vaccinated from infected animals, for example antigens that are not expressed by vaccines like Mycobacterium bovis Bacille-Calmette-Guérin, but recognised strongly in Mycobacterium bovis infected cattle. 相似文献
89.
90.
The Eurasian badger (Meles meles) is a significant source of bovine tuberculosis in cattle in the UK and Ireland. Protection from infectious diseases, arising from maternal antibody transfer, is a well-established immunological phenomenon in mammals. In a previous study of wild badgers, transient serological responses in cubs were taken as evidence of maternal antibody transfer, and it was speculated this conferred protection from subsequent mycobacterial excretion following acquisition of tuberculosis. However successful defence against mycobacterial infections is likely to be dominated by a cell-mediated response. Using a substantially larger dataset from the same badger population, we revisited the hypothesis of maternally derived protection. Whilst we found a significant association between transient serological responses and absence of subsequent Mycobacterium bovis excretion, the likelihood of detection of such responses was not significantly associated either with badger age, or with infection in the breeding females within a cub's natal group. We concluded that although maternal antibody transfer in badgers almost certainly occurs, transient serological responses represent an invalid proxy, and the reduced likelihood of M. bovis excretion associated with transient responses was more likely to be due to the lower sensitivity of the Brock ELISA test in detecting badgers with less advanced disease. 相似文献