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排序方式: 共有801条查询结果,搜索用时 406 毫秒
731.
732.
733.
H K Matthews E Hunt D E Duncan 《Journal of the American Veterinary Medical Association》1992,200(5):699-701
Ventral edema, dyspnea, fever, tachycardia, bloat and muffled heart sounds were identified in a 3-year-old heifer. Attempts to relieve the bloat by passing an orogastric tube were unsuccessful. The heifer was bovine leukemia virus-negative by the agar gel immunodiffusion test, and had normocytic, normochromic anemia, mature neutrophilia, and hyperproteinemia. Pleural effusion was identified by thoracic ultrasonography. Cytologic examination of pleural fluid revealed an increased number of atypical lymphocytes. The heifer died, and at necropsy, thymic and metastatic mammary lymphosarcoma was confirmed. 相似文献
734.
735.
I C Fulton F J Derksen J A Stick N E Robinson I D Duncan 《American journal of veterinary research》1992,53(4):592-596
A nerve muscle pedicle (NMP) graft was placed in the cricoarytenoideus dorsalis (CAD) muscle of 6 horses with induced left laryngeal hemiplegia. The NMP graft was created by use of the first cervical nerve and omohyoideus muscle. In 1 horse (control), the first cervical nerve was transected after placement of the NMP graft. One year after the surgical procedure, horses were examined endoscopically and then anesthetized. While the larynx was observed endoscopically, the first cervical nerve was stimulated. Horses were subsequently euthanatized, and the larynx was harvested. Prior to anesthesia, the endoscopic appearance of the larynx of all horses was typical of laryngeal hemiplegia. During anesthesia, stimulation of the first cervical nerve produced vigorous abduction of the left arytenoid in principal horses but not in the control horse. The right cricoarytenoideus lateralis and CAD muscles were grossly and histologically normal. Also, the left cricoarytenoideus lateralis was atrophic in all horses as was the left CAD muscle of the control horse. In contrast, the left CAD muscle harvested from principal horses had evidence of reinnervation with type 1 or type 2 fiber grouping. One year after the NMP graft procedure, horses with left laryngeal hemiplegia had reinnervation of the left CAD muscle. In another study, reinnervation was sufficient to allow normal laryngeal function during exercise. Combined, these data suggest that the NMP graft procedure is a viable technique for the treatment of left laryngeal hemiplegia in horses. 相似文献
736.
The structure of 9-hydroxy HEOD was examined by spectroscopic methods and by photolysis. The hydroxyl group was found to be hydrogen bonded to the epoxy group, and the product of photolysis was a hydroxylated analogue of the previously described photoisomer of HEOD. 相似文献
737.
Modelling the Effects of Dispersal and Landscape Configuration on Population Distribution and Viability in Fragmented Habitat 总被引:2,自引:2,他引:0
Jolyon?AldermanEmail author Duncan?McCollin Shelley A.?Hinsley Paul E.?Bellamy Phil?Picton Robin?Crockett 《Landscape Ecology》2005,20(7):857-870
Landscape configuration and dispersal characteristics are major determinants of population distribution and persistence in
fragmented habitat. An individual-based spatially explicit population model was developed to investigate these factors using
the distribution of nuthatches in an area of eastern England as an example. The effects of immigration and increasing the
area of breeding quality habitat were explored. Predictions were compared with observed population sizes in the study area.
Our model combined a nuthatch population simulator based on individual behaviour with a grid-based representation of the landscape;
nuthatch life cycle and immigration parameters were user selectable. A novel aspect of the model is user-selection of habitat
perceptual range. Using a realistic set of parameters, the number of breeding pairs predicted by the model matched observed
numbers. According to model simulations, the main cause of nuthatch scarcity in the study area was the inability of patches
to support viable populations without immigration from elsewhere. Modelled habitat management, which increased breeding quality
habitat in existing woods, lowered the threshold above which the study area population became self-sustaining. The existence
of a large core habitat area was critical in producing a self-sustaining population in this landscape, the same area in dispersed
small woods failed to sustain populations. 相似文献
738.
There is increased awareness of the need to clean the external surfaces of sprayers, but the extent to which the washings may impact on the environment is not known. Quantification of the levels of external residues on sprayers could give an indication of the potential environmental impact of sprayer cleaning. The presence of azoxystrobin, carbendazim, chlorothalonil, cyanazine, cypermethrin, epoxiconazole, flusilazole, isoproturon, kresoxim-methyl, metazachlor, pendimethalin, pirimicarb and tebuconazole on thirteen sprayers, sampled on two occasions was investigated. Composite samples were taken from the boom, nozzles and spray tank (delivery system) and the mudguard, cab door, rear window and windscreen (tractor body). Despite being subject to some form of cleaning, pesticides were detected on all sprayers. Residues were found at higher quantities and with greater frequency on the nozzles and booms, but the mean dose on the spray tank was equal to that on the mudguard (7.2 mg m(-2)). Isoproturon, pendimethalin, metazachlor, chlorothalonil and azoxystrobin were all detected above 1000 mg m(-2) on the delivery system, whereas on the tractor body the highest concentrations were between 100 and 1000 mg m(-2) (isoproturon, pendimethalin, chlorothalonil and carbendazim). On the whole, azoxystrobin was detected on the least number of occasions. However, there was great variation within and between compounds and sampling sites. Generally sprayers were not cleaned frequently or efficiently, enabling residues to accumulate on the external surfaces where they can remain for years. The findings here indicate that the quantity of these residues may be sufficient to be harmful to aquatic organisms should the residues enter a watercourse. In addition, if all the residues were removed by cleaning in the field and the washings catchment area was 15 m2 or less, overdosing could occur. Further work is required to assess whether a more frequent cleaning regime would reduce the overall environmental impact of cleaning sprayers. Implications for potential occupational exposure are considered elsewhere. 相似文献
739.
Shaw SC Wood JL Freeman J Littlewood JD Hannant D 《American journal of veterinary research》2004,65(7):1014-1020
OBJECTIVE: To estimate the heritability of atopic dermatitis in Golden and Labrador Retrievers. ANIMALS: 429 dogs related to 13 dogs with atopic dermatitis. PROCEDURE: Atopic dermatitis was defined on the basis of the type and frequency of clinical signs recorded in the clinical records, and each dog was classified with atopic dermatitis or probable atopic dermatitis or as nonatopic. By use of data from atopic and nonatopic dogs, regression analyses of parental status on offspring status were performed to estimate heritability. RESULTS: There was no difference in the frequency of atopic dermatitis between sexes or between breeds. There was a marked association between the atopic status of the parent and that of the offspring, particularly for sires. By use of data from 32 litters in which the status of both parents was known and considering only those dogs classified with atopic dermatitis or as nonatopic, the heritability (+/- SE) of atopic dermatitis was estimated to be 0.47 (+/- 0.17). CONCLUSIONS AND CLINICAL RELEVANCE: Atopic dermatitis has a strong genetic component, and breeding of dogs with clinical signs of atopic dermatitis should be discouraged. 相似文献
740.
Lascelles BD Henderson RA Seguin B Liptak JM Withrow SJ 《Journal of the American Animal Hospital Association》2004,40(2):137-146
This paper describes in detail an aggressive rostral maxillectomy procedure in one cat and six dogs, and the postoperative complications and outcomes are reported. The surgeries were performed to attempt complete excision of large and extensive rostral maxillary fibrosarcomas (n=4), squamous cell carcinomas (n=2), or poorly differentiated mesenchymal neoplasia (n=1). The surgeries involved transection of the maxilla at the level of premolar (PM)1 and PM2 in a cat and two dogs, and between PM2 and PM3 in four dogs. There were no intraoperative complications. Complete margins of resection were obtained in all cases. The postoperative appearance was acceptable to owners. Local recurrence was only observed in one dog (10 months after surgery) during a follow-up period of 11 to 66 months (median, 21.5 months). 相似文献