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11.
Significant breed differences were detected in fecal egg counts and fluke counts following experimental infection of five breeds of sheep with metacercariae of F. hepatica. Two experiments compared the responses of Barbados Blackbelly, St. Croix, Florida Native, Finn X Rambouillet and Targhee sheep to primary and challenge infections (Expt. 1) and to multiple infections (Expt. 2). Barbados Blackbelly sheep were more susceptible to infection than the other breeds in both experiments. St. Croix and Florida Native sheep were the most resistant breeds in Expt. 1, while Targhee and Florida Native were the most resistant in Expt. 2. There was no evidence of acquired immunity in any breed in either experiment. 相似文献
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Sean V. Murphy Rebecca Lim Philip Heraud Marian Cholewa Mark Le Gros Martin D. de Jonge Daryl L. Howard David Paterson Courtney McDonald Anthony Atala Graham Jenkin Euan M. Wallace 《PloS one》2012,7(9)
Cystic fibrosis, an autosomal recessive disorder caused by a mutation in a gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR), remains a leading cause of childhood respiratory morbidity and mortality. The respiratory consequences of cystic fibrosis include the generation of thick, tenacious mucus that impairs lung clearance, predisposing the individual to repeated and persistent infections, progressive lung damage and shortened lifespan. Currently there is no cure for cystic fibrosis. With this in mind, we investigated the ability of human amnion epithelial cells (hAECs) to express functional CFTR. We found that hAECs formed 3-dimensional structures and expressed the CFTR gene and protein after culture in Small Airway Growth Medium (SAGM). We also observed a polarized CFTR distribution on the membrane of hAECs cultured in SAGM, similar to that observed in polarized airway cells in vivo. Further, hAECs induced to express CFTR possessed functional iodide/chloride (I−/Cl−) ion channels that were inhibited by the CFTR-inhibitor CFTR-172, indicating the presence of functional CFTR ion channels. These data suggest that hAECs may be a promising source for the development of a cellular therapy for cystic fibrosis. 相似文献
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McGillicuddy EA Chaar CI Flynn C Villalona G Longo WE 《The Yale journal of biology and medicine》2010,83(3):113-117
Although the medical management of fistulizing Crohn's disease is improving, a subset of patients does not respond to maximal medical therapy and is referred for surgical consultation. We report a case of Crohn's colitis with an ingested foreign body resulting in a cologastric fistula. The patient underwent segmental colectomy and takedown of the cologastric fistula. At the time of laparotomy, the foreign body was found in the fistulous colonic segment. The presence of an ingested foreign body likely contributed to a rare fistula that was refractory to medical management. 相似文献
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ATP-dependent chromatin-remodeling complexes contribute to the proper temporal and spatial patterns of gene expression in mammalian embryos and therefore play important roles in a number of developmental processes. SWI/SNF-like chromatin-remodeling complexes use one of two different ATPases as their catalytic subunit: brahma (BRM, also known as SMARCA2) and brahma-related gene 1 (BRG1, also known as SMARCA4). We have conditionally deleted a floxed Brg1 allele with a Tie2-Cre transgene, which is expressed in developing hematopoietic and endothelial cells. Brg1(fl/fl):Tie2-Cre(+) embryos die at midgestation from anemia, as mutant primitive erythrocytes fail to transcribe embryonic alpha- and beta-globins, and subsequently undergo apoptosis. Additionally, vascular remodeling of the extraembryonic yolk sac is abnormal in Brg1(fl/fl):Tie2-Cre(+) embryos. Importantly, Brm deficiency does not exacerbate the erythropoietic or vascular abnormalities found in Brg1(fl/fl):Tie2-Cre(+) embryos, implying that Brg1-containing SWI/SNF-like complexes, rather than Brm-containing complexes, play a crucial role in primitive erythropoiesis and in early vascular development. 相似文献
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Variability in nitrogen stable isotope ratios of macroalgae: consequences for the identification of nitrogen sources 下载免费PDF全文
In our research, we collected and analyzed numerous macroalgal specimens (738) for isotopic analysis sampled over a year at monthly intervals across 20 sites within the Urías lagoon complex, a typical subtropical coastal ecosystem located in the Gulf of California. We quantified and characterized (chemically and isotopically) the N loads received by Urías throughout a year. We studied the spatial‐temporal variation of the chemical forms and isotopic signals of the available N in the water column, and we monitored in situ different environmental variables and other hydrodynamic parameters. Multiple N sources (e.g., atmospheric, sewage, seafood processing, agriculture and aquaculture effluents) and biogeochemical reactions related to the N cycle (e.g., ammonia volatilization, nitrification and denitrification) co‐occurring across the ecosystem, result in a mixture of chemical species and isotopic compositions of available N in the water column. Increased variability was observed in the δ15N values of macroalgae (0.41‰–22.67‰). Based on our results, the variation in δ15N was best explained by spatio‐temporal changes in available N and not necessarily related to the N sources. The variability was also explained by the differences in macroalgal biology among functional groups, species and/or individuals. Although the δ15N‐macroalgae technique was a useful tool to identify N sources, its application in coastal ecosystems receiving multiple N sources, with changing environmental conditions influencing biogeochemical processes, and high diversity of ephemeral macroalgal species, could be less sensitive and have less predictive power. 相似文献
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Direction of reading of the genetic message 总被引:16,自引:0,他引:16
M Salas M A Smith W M Stanley A J Wahba S Ochoa 《The Journal of biological chemistry》1965,240(10):3988-3995
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Courtney L. Olson Luz P. Acosta Natasha S. Hochberg Remigio M. Olveda Mario Jiz Stephen T. McGarvey Jonathan D. Kurtis David C. Bellinger Jennifer F. Friedman 《PLoS neglected tropical diseases》2009,3(10)