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排序方式: 共有1001条查询结果,搜索用时 19 毫秒
1.
A Chugun T Uchide K Temma R H Kennedy S V Klimberg Y Hara T Sasaki T Akera 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2001,63(12):1315-1322
During the study on the mechanism of doxorubicin-induced cardiotoxicity, we observed that a long incubation (4 hr) with doxorubicin reduced the maximal negative inotropic effects of a muscarinic receptor agonist, carbachol. The mechanism responsible for this doxorubicin-induced reduction of the efficacy of carbachol was examined in isolated guinea pig hearts. In isolated left atrial muscle preparations, 1 hr incubation with 100 microM doxorubicin caused a parallel right-ward shift of the concentration-response curves for carbachol, but a longer (4 hr) incubation with this agent (30, 100 or 200 microM), caused a significant reduction of the magnitude of the negative inotropic effect of carbachol in addition to the concentration-dependent parallel right-ward shift. The 4-hr incubation with these concentrations of doxorubicin also reduced the maximal negative inotropic effect of an adenosine A1 receptor agonist, R-phenylisopropyl adenosine (R-PIA), without affecting the potency of this agonist. Doxorubicin (1 to 100 microM) reduced [3H]quinuclidinyl benzilate (QNB) binding in a concentration dependent manner, but failed to alter [3HIR-PIA binding. The decrease in the magnitude of the maximal negative inotropic effect by doxorubicin was caused by changes in the muscarinic system at steps common to the transduction of muscarinic and adenosine A1 receptor mechanisms. 相似文献
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M Kennedy S Citino T Dolorico A H McNabb A S Moffat S Kania 《Journal of zoo and wildlife medicine》2001,32(1):25-30
Feline coronavirus genetic elements were detected by polymerase chain reaction from blood, fecal samples, and effusive fluid collected from 33 cheetahs in the U.S.A. Feline coronavirus-specific serum antibodies were also measured by indirect immunofluorescence. Ten cheetahs were positive for viral shedding by polymerase chain reaction, whereas 13 were seropositive by immunofluorescence. Results of serology did not consistently correlate with shedding of virus, and the capture antigen used for detection of feline coronavirus-specific antibodies had a significant impact on results. Testing of samples from one population over a 1-yr period indicated chronic infection in some animals. These relatively healthy carrier animals were a source of virus for contact animals. Screening programs in cheetah populations for feline coronavirus infection may be most reliable if a combination of serologic analysis and viral detection by polymerase chain reaction is used. 相似文献
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Melissa Kennedy Cheryl B Greenacre 《Veterinary Clinics of North America: Exotic Animal Practice》2005,8(1):1-6
A basic understanding of viruses and how they replicate and produce disease can aid in the management of virus infections. Parameters, such as clinical signs, sample and test selection, prognosis, and control, are implicit in this understanding. Information increases almost daily about known and emerging viruses; this impacts our ability to manage and control infections. 相似文献
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Enzyme activities and microbial community structure in semiarid agricultural soils 总被引:15,自引:0,他引:15
Acosta-Martínez V. Zobeck T. M. Gill T. E. Kennedy A. C. 《Biology and Fertility of Soils》2003,38(4):216-227
This study investigated the effect of management on -glucosidase, -glucosaminidase, alkaline phosphatase, and arylsulfatase activities and the microbial community structure in semiarid soils from West Texas, USA. Surface samples (0–5 cm) were taken from a fine sandy loam, sandy clay loam, and loam that were under continuous cotton ( Gossypium hirsutum L.) or in cotton rotated with peanut ( Arachis hypogaea L.), sorghum ( Sorghum bicolor L.), rye ( Secale cereale) or wheat ( Triticum aestivum L.), and had different water management (irrigated or dryland), and tillage (conservation or conventional). The enzyme activities were higher in the loam and sandy clay loam than in the fine sandy loam. Soil pH was not affected by management, but the soil organic C and total N contents were generally affected by the different crop rotations and tillage practices studied. The trends of the enzyme activities as affected by management depended on the soil, but in general crop rotations and conservation tillage increased the enzyme activities in comparison to continuous cotton and conventional tillage. The soil enzyme activities were significantly correlated with the soil organic C ( r -values up to 0.90, P< 0.001), and were correlated among each other ( r -values up to 0.90, P <0.001). There were differences in the fatty acid methyl ester profiles between the fine sandy loam and the sandy clay loam and loam, and they reflected the differences in the enzyme activities found among the soils. For example, a 15:0 ranged from 1.61±0.25% in cotton-peanut/irrigated/no-till in the fine sandy loam to 3.86±0.48% in cotton-sorghum/dryland/conservation tillage in the sandy clay loam. There were no differences due to management within the same soil.Trade names and company names are included for the benefit of the reader and do not infer any endorsement or preferential treatment of the product by USDA-ARS 相似文献
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1996—2001年的六年间,全球转基因作物种植面积增加了30多倍,从1996年的170万hm2增加到了2001年的5260万hm2。其中发展中国家为1350万hm2,发达国家转基因作物增加的种植面积(560万hm2)是发展中国家(280万hm2)的2倍。2001年,四个国家占据了全球转基因作物种植面积的99%,其中美国为3570万hm2(占68%),阿根廷为1180万hm2(占22%),加拿大320万hm2(占6%),中国150万hm2(占3%)。中国的年增长率最高,抗虫棉的种植面积从2000年的50万hm2增加… 相似文献
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Erin Massender Luiz F. Brito Angela Cnovas Christine F. Baes Delma Kennedy Flavio S. Schenkel 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2021,138(1):91-107
Genetic selection for carcass traits is paramount to maximize the profitability and long‐term sustainability of any meat‐producing livestock species. The main objectives of this research were to evaluate the efficiency of indicator traits for the genetic improvement of lamb carcass traits and to determine the value of including carcass traits into terminal sire selection indexes for the Canadian sheep industry. The carcass traits included hot carcass weight (HCW), fat depth at the GR site (FATGR) and average carcass conformation score (AVGCONF), and were measured on heavy lambs (slaughter age less than 365 days and HCW greater than 16.3 kg) in commercial abattoirs. Growth traits were found to be moderately efficient indicator traits for the genetic improvement of HCW but selection on ultrasound traits was necessary to substantially improve the carcass quality traits (FATGR and AVGCONF). Economic selection indexes were designed by adding various combinations of carcass traits into the Canadian Sheep Genetic Evaluation System terminal indexes. Records measured on individuals and progeny were assumed to be the sources of information for live animal and carcass traits, respectively. The changes in index accuracy, efficiency and expected correlated response were used to assess the value of their inclusion. HCW was found to have a large economic value, and its inclusion into terminal selection indexes was expected to substantially increase their accuracy (0.08–0.12 points) and efficiency (20%–30%). However, further including FATGR (measured 110 mm from the carcass midline over the 12th rib) and AVGCONF had little impact on the accuracy (≤0.03) and efficiency (1%–7%) of the proposed indexes. Thus, the inclusion of carcass traits into the existing terminal selection indexes could be beneficial for the genetic improvement of HCW, but further research is needed to determine optimal methods of increasing carcass fatness and muscularity. 相似文献