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排序方式: 共有744条查询结果,搜索用时 15 毫秒
91.
Hsu CL Lin W Seshasayee D Chen YH Ding X Lin Z Suto E Huang Z Lee WP Park H Xu M Sun M Rangell L Lutman JL Ulufatu S Stefanich E Chalouni C Sagolla M Diehl L Fielder P Dean B Balazs M Martin F 《Science (New York, N.Y.)》2012,335(6064):89-92
Lysosomal storage diseases (LSDs) are a group of heterogeneous disorders caused by defects in lysosomal enzymes or transporters, resulting in accumulation of undegraded macromolecules or metabolites. Macrophage numbers are expanded in several LSDs, leading to histiocytosis of unknown pathophysiology. Here, we found that mice lacking the equilibrative nucleoside transporter 3 (ENT3) developed a spontaneous and progressive macrophage-dominated histiocytosis. In the absence of ENT3, defective apoptotic cell clearance led to lysosomal nucleoside buildup, elevated intralysosomal pH, and altered macrophage function. The macrophage accumulation was partly due to increased macrophage colony-stimulating factor and receptor expression and signaling secondary to the lysosomal defects. These studies suggest a cellular and molecular basis for the development of histiocytosis in several human syndromes associated with ENT3 mutations and potentially other LSDs. 相似文献
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Concerns exist that some uses of antimicrobials in cattle may lead to the emergence, proliferation, dissemination and persistence of resistant pathogenic bacteria in animal agriculture, which in turn can infect humans via the food supply. The degree of perceived risk varies with the clinical indication for which the antimicrobial in question is used. In this study, four uses of antimicrobials are considered, including in acutely sick, chronically sick, at-risk, and high-risk cattle, contrasting the degree of risk among these uses. Using a random sample of 103 feedlot cattle veterinarians and variables drawn from the theory of planned behavior, we predict differences in risk perception by clinical indication with differences in perceived efficacy of antimicrobials, social pressures to use antimicrobials, and moral obligations to use antimicrobials. In most models, veterinarians who perceived that others in the feedlot industry (i.e., other feedlot veterinarians, nutritionists, feedlot clients, and retained owners of cattle) were more likely to expect them to use antimicrobials in one situation versus another, the less likely those veterinarians perceived the risk of antimicrobial risk to be greater in the former versus the latter situation. Only two of these contrasts contained influences outside the immediate feedlot relationships. This exception involves the 'downstream' public: meat packers, retailers, and consumers. Veterinarians who believe that using antimicrobials for acutely sick cattle is more beneficial than using antimicrobials for chronically sick cattle were more likely to believe that antimicrobial resistance was a less probable outcome in acutely sick cattle than in chronically sick cattle. 相似文献
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Western juniper (Juniperus occidentalis Hook.) encroachment and exotic annual grass (medusahead [Taeniatherum caput-medusae L. Nevski] and cheatgrass [Bromus tectorum L.]) invasion of sagebrush (Artemisia L.) communities decrease ecosystem services and degrade ecosystem function. Traditionally, these compositional changes were largely confined to separate areas, but more sagebrush communities are now simultaneously being altered by juniper and exotic annual grasses. Few efforts have evaluated attempts to restore these sagebrush communities. The Crooked River National Grassland initiated a project to restore juniper-encroached and annual grass-invaded sagebrush steppe using summer (mid-July) applied prescribed fires and postfire seeding. Treatments were unburned, burned, burned and seeded with a native seed mix, and burned and seeded with an introduced seed mix. Prescribed burning removed all juniper and initially reduced medusahead cover but did not influence cheatgrass cover. Neither the native nor introduced seed mix were successful at increasing large bunchgrass cover, and 6 yr post fire, medusahead cover was greater in burned treatments compared with the unburned treatment. Large bunchgrass cover and biological soil crusts were less in treatments that included burning. Exotic forbs and bulbous bluegrass (Poa bulbosa L.), an exotic grass, were greater in burned treatments compared with the unburned treatment. Sagebrush communities that are both juniper encroached and exotic annual grass invaded will need specific management of both juniper and annual grasses. We suggest that additional treatments, such as pre-emergent herbicide control of annuals and possibly multiple seeding events, are necessary to restore these communities. We recommend an adaptive management approach in which additional treatments are applied on the basis of monitoring data. 相似文献
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Dean RS Helps CR Gruffydd Jones TJ Tasker S 《Journal of Feline Medicine and Surgery》2008,10(4):413-417
Feline haemoplasma infection can cause haemolytic anaemia. The natural method of transmission of haemoplasmas between cats is currently unknown but the nature of some of the risk factors for infection suggests that saliva may act as a mode of transmission. The aim of this study was to determine if Mycoplasma haemofelis (Mhf) and 'Candidatus Mycoplasma haemominutum' (CMhm) DNAs could be amplified from saliva and salivary gland samples collected from haemoplasma-infected cats. 相似文献