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排序方式: 共有81条查询结果,搜索用时 15 毫秒
41.
van Vuuren M Steinel A Goosen T Lane E van der Lugt J Pearson J Truyen U 《Journal of the South African Veterinary Association》2000,71(3):140-143
The low incidence of clinical signs or pathological lesions compatible with feline panleukopenia in cats has created the perception among practitioners that the disease has disappeared since the emergence of canine parvovirus type 2 in the late 1970s. Three parvoviruses that were recently isolated from a domestic cat and 2 cheetahs in cell culture or detected by means of the polymerase chain reaction were shown to be typical feline parvoviruses. Phylogenetic comparison with other FPV isolates did not reveal a particular African cluster. 相似文献
42.
Möhr AJ Lobetti RG van der Lugt JJ 《Journal of the South African Veterinary Association》2000,71(4):232-239
This retrospective study describes 4 cases of canine babesiosis with histologically confirmed acute pancreatitis. In addition, 16 dogs with babesiosis are reported with serum amylase (>3500 U/l) and/or lipase (>650 U/l) activity elevations of a magnitude that would support a diagnosis of probable acute pancreatitis, although extra-pancreatic sources of the enzymes could not be excluded in these cases. Median time of pancreatitis diagnosis was 2.5 days post-admission, with primarily young (median age 3 years), sexually intact dogs affected. The development of pancreatitis was unrelated to the degree of anaemia at time of admission. In addition to pancreatitis, 80% of cases suffered from other babesial complications, namely icterus (13), acute respiratory distress syndrome (6), immune-mediated haemolytic anaemia (6), renal failure (3), haemoconcentration (2) and cerebral syndrome (2). Acute respiratory distress syndrome, renal failure and cerebral syndrome were associated with a poor prognosis, with 4 of the 5 dogs included in the overall 26% mortality rate having at least 1 of these complications. Haemolytic anaemia with ischaemia-reperfusion injury to the pancreas is proposed as a possible primary pathophysiological mechanism in babesial pancreatitis. Hypotensive shock, immune-mediated haemolytic anaemia, haemoconcentration and possibly altered lipid metabolism in babesiosis may also be involved. The previously postulated pro-inflammatory cytokine milieu of complicated babesiosis may underlie the progression, if not the primary initiation, of pancreatic pathology. Acute pancreatitis may represent the previously reported 'gut' form of babesiosis. 相似文献
43.
Shy seed production in orchards of Eucalyptus nitens is a major barrier to the deployment of genetic gain in South African plantations. A machine learning method was used to identify optimal sites for the establishment of E. nitens seed orchards within the plantation forestry landscape of the summer rainfall region of South Africa. The ensemble classifier random forests (RF) was used to identify the environmental factors conducive to E. nitens floral bud production, and, based on these, build a predictive model deployable to the plantation forestry landscape for identifying suitable areas for E. nitens seed orchards. The RF model predicted site suitability likelihood for floral bud production with a high level of accuracy (area under the receiver operating characteristic curve = 0.83). Within the climatically optimal range for growing E. nitens, flower bud production was more abundant and consistent on cold slopes, i.e. sites experiencing lower minimum air temperatures during spring and autumn. The model was applied to the commercial plantation forestry landscape for the purpose of indicating sites climatically optimal for floral bud production in E. nitens and the establishment of breeding and seed production orchards of the same species. 相似文献
44.
MA Subramanian BH Toby AP Ramirez WJ Marshall AW Sleight GH Kwei 《Science (New York, N.Y.)》1996,273(5271):81-84
Structural analysis from powder neutron and single-crystal x-ray diffraction data for a sample of the Tl2Mn2O7 pyrochlore, which exhibits colossal magnetoresistance (CMR), shows no deviations from ideal stoichiometry. This analysis gives an Mn-O distance of 1.90 angstroms, which is significantly shorter than the Mn-O distances (1.94 to 2.00 angstroms) observed in phases based on LaMnO3 perovskites that exhibit CMR. Both results in Tl2Mn2O7 indicate oxidation states very close to Tl23+Mn24+O7. Thus, Tl2Mn2O7 has neither mixed valence for a double-exchange magnetic interaction nor a Jahn-Teller cation such as Mn3+, both of which were thought to have an important function in CMR materials. An alternate mechanism for CMR in Tl2Mn2O7 based on magnetic ordering driven by superexchange and strong spin-fluctuation scattering above the Curie temperature is proposed here. 相似文献
45.
SENICZAK STANISŁAW KLIMEK ANDRZEJ GACKOWSKI GRZEGORZ KACZMAREK SŁAWOMIR ZALEWSKI WOJCIECH 《Water, air, and soil pollution》1997,97(3-4):287-302
Water, Air, &; Soil Pollution - The soil mites were investigated in the areas covered with dead needles in young Scots pine forests (plant association Leucobryo-Pinetum), polluted by a copper... 相似文献
46.
47.
C J Trichard P A Basson J J Van der Lugt E P Jacobsz 《The Onderstepoort journal of veterinary research》1989,56(4):277-284
An outbreak of contagious bovine pleuropneumonia (CBPP) in the Owambo Mangetti area of South West Africa/Namibia in 1982 led to the slaughter of 3,153 cattle. The lungs of 266 of these animals were scrutinized for gross lesions of CBPP and samples of lung tissue, sequestral contents or pleural fluid were submitted to the Veterinary Research Institute (VRI), Onderstepoort for microbiological, immunofluorescent and pathological examination. Immunofluorescence proved to be the most successful method of diagnosis producing 96% of positives, while mycoplasma isolations were only positive in 64% of the 55 specimens processed in parallel. This clearly demonstrated the value of the former technique in the accurate as well as rapid diagnosis of CBPP. The impression smear technique employed, using Eriochrome black counterstaining proved most satisfactory and easy to interpret. The isolation of M. mycoides was influenced by the transit times and temperature of the samples on arrival at the VRI. No pathogenic bacteria were found in routine aerobic bacterial cultures from 27 of the samples submitted. Complement fixing antibodies were present in the sera of 16 cattle and titres varied between 10 and 320. Animals in which antibodies were absent included those with early lung lesions and some with sequestra. 相似文献
48.
49.
J J van der Lugt P W Nel J P Kitching 《The Onderstepoort journal of veterinary research》1991,58(3):211-221
The clinical features and pathological findings of 6 steers drenched with dried plant material of Cestrum laevigatum are described. Doses ranging from 0.5 to 10 g/kg/day were given intraruminally for 1 to 38 days. Animals that received 5 to 10 g/kg/day showed nervous signs including ataxia, muscle tremors, hypersensitivity and intermittent chewing. Clinical signs in the steers which received 0,5 to 4 g/kg/day were mild. High doses induced moderate to severe hepatosis characterized by centrilobular to midzonal coagulative necrosis, haemorrhage and congestion. At lower rates only mild hepatic lesions, characterized by disappearance of hepatocytes and collapse of the reticulin stroma in the centrilobular areas were evident. Ultrastructural changes were primarily limited to the hepatocytes and comprised degeneration, necrosis and fatty change. Degeneration and necrosis of endothelial cells and disruption of sinusoidal walls were occasionally observed. 相似文献
50.
The induction of second-growth in potato tubers 总被引:1,自引:0,他引:1