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61.
62.
Ultrastructural features of Cowdria ruminantium in midgut epithelial cells and salivary glands of nymphal Amblyomma hebraeum 总被引:2,自引:0,他引:2
K M Kocan J D Bezuidenhout A Hart 《The Onderstepoort journal of veterinary research》1987,54(1):87-92
Colonies of Cowdria ruminantium were studied in midgut epithelial cells and salivary gland acini of nymphal Amblyomma hebraeum that were infected experimentally as larvae. Colonies were found in both tissues and studied with light and electron microscopy. Colonies observed within gut cells frequently contained 2 types of the organism: electron-dense and reticulated forms. The morphology of colonies from salivary glands, as seen with light microscopy, varied from compact, densely-staining, small colonies to larger ones in which individual organisms were apparent. With electron microscopy, most organisms in salivary glands were reticulated and appeared to be dividing by binary fission. In both types of host cells, colonies often contained a dense inclusion to which reticulated organisms were adhered. 相似文献
63.
R A Levine A H Hart S C Wardlaw 《Journal of the American Veterinary Medical Association》1986,189(6):670-673
Using quantitative buffy coat analysis (QBCA), rapid and accurate measurements can be made of the erythrocyte PCV, total WBC count, and platelet count, and the leukocyte population can be differentiated into total granulocytes (including quantitation of eosinophils), and lymphocytes and monocytes. The QBCA is performed by placing a blood sample (50 to 111 microliters) into a high-precision-bore microhematocrit tube that contains a freely moving, closely fitting, cylindrical plastic float. After centrifugation for 5 minutes, the buffy coat components separate by density. The plastic cylinder floats in the buffy coat, thereby expanding the lengths of the buffy coat layers. The layers are measured in a manner that is similar to that used for measuring PCV. Results of QBCA of blood samples from dogs, cats, and horses indicated that the hematologic values obtained correlated with results obtained by use of conventional methods. The accuracy and ease of use of QBCA and the availability of results while the animal is still being examined make QBCA a useful tool for hematologic evaluation of animals. 相似文献
64.
M V Hart J R Rowles A R Hohimer M J Morton J D Hosenpud 《American journal of veterinary research》1984,45(11):2328-2330
The resting hemodynamics were determined in 8 guinea pigs after they were anesthetized with ketamine/xylazine. Measurements were made of blood pressure, heart rate, cardiac output, arterial blood gases, and pH. These measurements were obtained initially at 4 to 5 hours after an injection (IM) of ketamine HCl (25 mg) and xylazine (0.15 mg) was given to anesthetize the animals for catheterization (period 1), again 5 days after the operation (period 2), and finally 4 to 5 hours after a 2nd injection of ketamine/xylazine (period 3). There were no differences in heart rates, respiratory rates, or cardiac outputs among the 3 study periods. However, arterial blood pressure was slightly, but significantly, lowered after, and presumably due to, instrumentation (62 +/- 4 mm of Hg, P less than 0.05) when compared with the 5-day postoperative period (67 +/- 7 mm of Hg) or after the readministration of anesthetics (66 +/- 7 mm of Hg). The partial pressure of carbon dioxide in the arterial blood was slightly lower (4 mm of Hg, P less than 0.05) in both acutely postanesthetic periods (period 1 and period 3) than in the same animals at postoperative day 5 (period 2). This study has demonstrated that resting hemodynamics measured shortly after this anesthesia with ketamine/xylazine are not largely different from those in chronically instrumented animals. 相似文献
65.
ENTEROTOXAMEMIA OF CALVES DUE TO CLOSTRIDIUM WELCHII TYPE E 总被引:1,自引:0,他引:1
66.
Acetylocholine, arecoline, 2-(dimethylamino)ethyl acetate, L-glutamic acid, L-4-methyl-eneglutamic acid, (±)-quisqualic acid, 4-aminobutyric acid, and dicrotophos were injected into the haemocoel of adult male Lucilia sericata. Large doses of the putative transmitters and their analogues were required for toxicity. The water soluble organo-phosphate dicrotophos was much more toxic than any of the other compounds. Electrophysiological experiments indicated that the putative transmitters were reaching their presumed site of action in the nervous system and that their toxicity could be correlated with the intensity and duration of their effect at this site. Biochemical measurements of the rate of loss of the putative transmitters from the haemolymph indicate that, in vivo, the test insect possesses efficient mechanisms for removing these compounds from the system being studied. It is concluded that the low toxicity of the putative transmitters, which are presumed to interact reversibly with post synaptic receptor sites, may be largely due to their rapid removal from the system, resulting in a rapid fall in concentration at the receptor site. 相似文献
67.
B L Hart 《Veterinary Clinics of North America: Food Animal Practice》1987,3(2):383-391
The behavior of the sick animal is not necessarily a result of physical debilitation; it can be viewed as part of a highly organized adaptive strategy that is at times critical to survival if the animal were living in the wild state. Domestic ruminants appear to have retained this behavioral mode when they are sick. This article brings together several lines of current research about depression, appetite control, and the role of fever in facilitating an animal's ability to combat viral and bacterial infections. 相似文献
68.
69.
A probabilistic model was developed to estimate target and non-target avian mortality associated with the application of the avicide CPTH (3-chloro-p-toluidine hydrochloride) to minimize sprouting rice damage in the southern USA. CPTH exposures for individual birds were predicted by random sampling from species-specific non-parametric distributions of bait seed consumption and CPTH residues detected on individual bait seeds. Mortality was predicted from the species-specific exposure versus mortality relationship. Individual variations in this response were captured in the model by Monte Carlo sampling from species-specific distributions of slopes and median toxicity values (LD50) for each bird. The model was used to simultaneously predict mortality (percentage of exposed population and number of birds killed/weight of consumed bait) for a target (blackbird) and non-target (mourning dove) species feeding on bait sites for up to five consecutive days. 相似文献
70.