Evaluation of glycoprotein Ib expression on feline platelets     

Tablin F  Johnsrude JD  Walker NJ 《American journal of veterinary research》2001,62(2):195-201

OBJECTIVE: To determine whether platelets obtained from cats expressed glycoprotein Ib (GPIb). SAMPLE POPULATION: Platelets obtained from 11 specific-pathogen-free cats. PROCEDURE: Platelets were analyzed by use of immunofluorescence microscopy, flow cytometry, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, western immunoblot analysis, and immunoprecipitation. RESULTS: Immunofluorescence microscopy and flow cytometry revealed the protein on the surface of feline platelets. Biochemical studies (western immunoblot analysis and immunoprecipitation) revealed a 140-kd membrane glycoprotein. Additional biochemical studies revealed that feline GPIb was sensitive to proteolysis, because platelet cytoskeletons prepared with low concentrations of a calpain inhibitor (ie, leupeptin; 100 microg/ml) had substantial proteolysis, and there was an association of protein fragments with the actin cytoskeleton. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of these results indicate that feline platelets express a 140-kd membrane protein that is recognized by monoclonal antibodies developed against GPIb. Application of standardized ELISA to quantitate glycocalicin, the water-soluble fragment of GPIb, may provide important information on the production of microvesicles, increased platelet turnover, and abnormal proteolysis.  相似文献   

Postprandial venous ammonia concentrations in the diagnosis of hepatobiliary disease in dogs     

Walker MC  Hill RC  Guilford WG  Scott KC  Jones GL  Buergelt CD 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2001,15(5):463-466

A postprandial ammonia tolerance test (PPATT) was performed on normal dogs and dogs with signs that suggested they may have liver disease. All dogs underwent transcolonic scintigraphy, liver biopsy, or both and were assigned to extrahepatic disease, primary hepatocellular, and congenital portosystemic vascular anomalies (PSVA) groups. Each dog was fed a chicken and rice diet providing 25% of its estimated daily metabolizable energy requirement (MER) as an ammonia challenge. This is practical in patients with liver disease because ammonium chloride administration often causes vomiting or ammonia toxicity. Venous ammonia concentrations were measured before feeding and every 2 hours after feeding for 8 hours. No difference in mean ammonia concentrations between dogs with extrahepatic disease and control dogs was found. Therefore, the specificity of the PPATT was 100%. Dogs with hepatocellular disease showed no change in mean ammonia concentration at any time point, before or after feeding, but sensitivity was greatest when venous ammonia was measured 6 hours after feeding (sensitivity before feeding, 28%, and after feeding, 36%). Among dogs with congenital PSVA, mean ammonia concentrations were higher than the reference range at all time points before and after feeding, and peak mean ammonia concentration occurred 6 hours after feeding. In this group, the sensitivity of the PPATT was 81% before feeding and 91% 6 hours after feeding. This study demonstrates that the measurement of venous ammonia concentration is a useful test to detect congenital PSVA, and the sensitivity of the test may be improved by sampling 6 hours after feeding. The PPATT has poor sensitivity in detecting primary hepatocellular disease.  相似文献   

A comparative study of carbofuran metabolism in treated and untreated soils     

Khalil Talebi  Colin H. Walker 《Pest management science》1993,39(1):65-69

Soils which have been pretreated with carbofuran can degrade the insecticide more rapidly than untreated soils, with a consequent loss of efficacy. In laboratory studies, soils pretreated with carbofuran were found to degrade the chemical more rapidly than soils which were not so pretreated. When pretreated soils were sterilised, the rate of carbofuran degradation was much reduced, indicating that most of it was due to microbial action. Incubation of pretreated soil with [phenyl-U-¹⁴C]carbofuran led to the rapid disappearance of the parent compound (3 % left after seven days). Most of the ¹⁴C was accounted for as bound residue after seven days, whilst smaller amounts were recovered as carbon dioxide, 3-hydroxycarbofuran, 3-ketocarbofuran, and an unknown metabolite. Incubation of pretreated soil with [carbonyl-¹⁴C]carbofuran led to rapid loss of the parent compound and the recovery of 73% of ¹⁴C as carbon dioxide by five days. Most of the bound ¹⁴C (>90%) arising from [phenyl-U-¹⁴C]carbofuran treatment of pretreated soil was extracted by 1 M sodium hydroxide and about half of the extracted ¹⁴C was precipitated with ‘humic acids’ after acidification. These and other results suggest that the major metabolic route for carbofuran in pretreated soils involves hydrolysis of the ester bond leading to (1) release of carbofuran phenol which rapidly binds to soil organic matter and, (2) release of the carbonyl moiety which quickly degrades to generate carbon dioxide.  相似文献   

Increased interleukin-6 activity in the serum of ponies acutely infected with equine infectious anaemia virus     

Sellon DC  Russell KE  Monroe VL  Walker KM 《Research in veterinary science》1999,66(1):77-80

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The effect of dose and line on immunisation of cattle with lymphoblastoid cells infected with Theileria annulata   总被引：1，自引：0，他引：1  

H Ouhelli  E A Innes  C G Brown  A R Walker  S P Simpson  R L Spooner 《Veterinary parasitology》1989,31(3-4):217-228

Thirty-one Friesian calves in Morocco susceptible to tropical theileriosis were protected against a lethal sporozoite challenge by prior infection with lymphoblastoid cell lines infected and transformed in vitro by a Moroccan stock of Theileria annulata. The challenge infection of cryopreserved sporozoites killed all four susceptible control calves within 20 days. Four schizont-infected cell cultures at Passage 3 were inoculated at four different doses, 10(8), 10(6), 10(4) and 10(2), into pairs of calves. The recipient animals showed great variation in severity of disease symptoms, which did not show a linear correlation with the cell dose inoculated. The most severe disease symptoms were recorded, prior to challenge, in the 10(2) cell dose recipients; one animal died of acute theileriosis and another had to be treated. One of the four cell lines used was more virulent than the other three. Two years after the completion of this experiment, immunised animals have shown normal productivity traits.  相似文献   

Effects of age and of early lighting on ovarian function in breeding turkeys     

P M Hocking  A B Gilbert  C C Whitehead  M A Walker 《British poultry science》1988,29(2):223-229

1. Yellow follicle numbers and production of defective egg shells were greater in the early part of the laying period in conventionally-reared turkeys photostimulated at 24 rather than 30 weeks of age. 2. The number of yellow follicles declined with age and were similar in both groups at 40 weeks of age. 3. At 55 weeks of age more birds photostimulated at 24 weeks were out of lay and birds in lay had fewer yellow follicles and more atresia compared with turkeys photostimulated at 30 weeks of age. 4. The numbers of white follicles in the 1 to less than 2 mm size were similar in the two groups at each age. The proportion of white follicles which were atretic was negatively related to the number of yellow follicles, particularly in follicles 5 to less than 8 mm diameter.  相似文献   

Aberrant leucocytozoon infection in parakeets     

D Walker  P C Garnham 《The Veterinary record》1972,91(3):70-72

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Cordophilus sagittus in Swaziland     

W D Walker 《The Veterinary record》1971,88(13):342-343

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Rabies today--man and animals.   总被引：1，自引：1，他引：0       下载免费PDF全文

V C Walker 《The Canadian veterinary journal. La revue veterinaire canadienne》1969,10(1):11-17

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Particle track etching   总被引：1，自引：0，他引：1  

R L Fleischer  H W Alter  S C Furman  P B Price  R M Walker 《Science (New York, N.Y.)》1972,178(58):255-263

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