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排序方式: 共有652条查询结果,搜索用时 15 毫秒
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Occlusion of varicoceles wih detachable balloons 总被引:1,自引:0,他引:1
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Pathogenesis and inflammatory response to Edwardsiella tarda infection in the zebrafish 总被引:5,自引:0,他引:5
Pressley ME Phelan PE Witten PE Mellon MT Kim CH 《Developmental and comparative immunology》2005,29(6):501-513
The zebrafish (Danio rerio) is a widely used model for developmental biology, neurobiology, toxicology, and genetic disease. Recently, the zebrafish has been recognized as a valuable model for infectious disease and immunity. In this study the pathogenesis and inflammatory cytokine response of zebrafish to experimental Edwardsiella tarda infection was characterized. In challenge experiments, zebrafish embryos were susceptible to infection by immersion. Adult fish were susceptible to challenge by intraperitoneal (ip) injection but not static immersion unless the epithelial layer was perturbed by scraping prior to exposure. To determine if E. tarda infection induces a typical acute inflammatory response, mRNA expression levels of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNFalpha) were assessed by quantitative real-time PCR. The expression levels of IL-1beta and TNFalpha were significantly upregulated in infected zebrafish embryos and adults. The methods developed in this study will be particularly valuable for targeted gene disruption studies of host immune components and in zebrafish genetic screens. 相似文献
96.
Upriver spawning migration of starving Atlantic salmon (Salmo salar) involves drastic skeletal alterations, among which a toothless stage followed by the appearance of a new set of so-called breeding teeth has been described. To investigate this phenomenon, we examined the patterns of tooth replacement on the lower jaws in different life stages of wild animals before and after spawning. Prior to spawning, every position held either a functional or a replacement tooth, both in first-time (grilse) and repetitive (salmon) spawners. Teeth were in a similar developmental stage every three positions along the tooth row. A functional tooth occurred in every third position and intermediate positions were taken by developing teeth. Within the process of replacement, teeth were resorbed and not shed. Our observations on an uninterrupted tooth replacement pattern provided no evidence of an intermediate toothless stage nor of a specialized breeding-teeth generation. Only animals that survived spawning (kelts) showed a highly variable tooth pattern, but with the initial "every third position" pattern still recognizable in some animals. We hypothesise that previous accounts describing a complete tooth loss/replacement relate to proliferation of the oral mucosa that conceals the teeth prior to the breeding period and to the use of maceration techniques that could have removed all teeth with an incompletely mineralised base. 相似文献
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E-K Park EJ Lee S-H Lee KH Koo JY Sung EH Hwang JH Park C-W Kim K-C Jeong B-K Park Y-N Kim 《British journal of pharmacology》2010,160(5):1212-1223
Background and purpose:
Lipid rafts and caveolae are membrane microdomains with important roles in cell survival signalling involving the Akt pathway. Cholesterol is important for the structure and function of these microdomains. The ginsenoside Rh2 exhibits anti-tumour activity. Because Rh2 is structurally similar to cholesterol, we investigated the possibility that Rh2 exerted its anti-tumour effect by modulating rafts and caveolae.Experimental approach:
A431 cells (human epidermoid carcinoma cell line) were treated with Rh2 and the effects on cell apoptosis, raft localization and Akt activation measured. We also examined the effects of over-expression of Akt and active-Akt on Rh2-induced cell death.Key results:
Rh2 induced apoptosis concentration- and time-dependently. Rh2 reduced the levels of rafts and caveolae in the plasma membrane and increased their internalization. Furthermore, Akt activity was decreased and consequently, Akt-dependent phosphorylation of Bad, a pro-survival protein, was decreased whereas the pro-apoptotic proteins, Bim and Bax, were increased upon Rh2 treatment. Unlike microdomain internalization induce by cholesterol depletion, Rh2-mediated internalization of rafts and caveolae was not reversed by cholesterol addition. Also, cholesterol addition did not restore Akt activation or rescue cells from Rh2-induced cell death. Rh2-induced cell death was attenuated in MDA-MB-231 cells over-expressing either wild-type or dominant-active Akt.Conclusions and implications:
Rh2 induced internalization of rafts and caveolae, leading to Akt inactivation, and ultimately apoptosis. Because elevated levels of membrane rafts and caveolae, and Akt activation have been correlated with cancer development, internalization of these microdomains by Rh2 could potentially be used as an anti-cancer therapy. 相似文献100.
Nagi Idris Jo Neill Ben Grayson Benny Bang-Andersen Louise M. Witten Lise Tøttrup Brennum Jørn Arnt 《Psychopharmacology》2010,208(1):23-36