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991.
首先简要回顾了微电子机械系统技术研究进展,然后介绍了一种基于微处理器的消化道内按摩装置的基本结构,工作原理和特点。尤其详细介绍了采用MSP430F123微处理器产生周期脉冲,来控制整个按摩胶囊的供电。总的说来,消化道内按摩装置具有重要的临床应用价值和商业价值,开发消化道内按摩装置对我国生物医学工程产业和微电子机械系统产业的发展都有着积极和深远的意义。 相似文献
992.
眉部运动的显微外科解剖学研究及其临床意义 总被引:8,自引:0,他引:8
目的:为解决除皱术中眉毛上提效果欠佳,不够持久的问题。方法:对10例新鲜尸体进行了大体及显微解剖。结果:证实了额肌深面“滑动层”和“滑动间隙”的存在,观察了眉内侧2/3自皮肤向深面发出固定到眉嵴处的眉毛支持韧带,外侧上方的颞融合线和下方的眉限制韧带静态固定结构,上述结构决定了眉毛的形态;阐述了额肌、皱眉肌和降眉肌的眉毛动力机制,探讨了老年性外侧眉毛下垂主要由于外侧的滑动脂肪垫向下“疝出”所致。结论:通过破坏“滑动间隙”,切断颞融合线和眉限制韧带,切除外侧滑动脂肪垫,达到眉部上提的良好、持久效果。 相似文献
993.
994.
Effects of recombinant human growth hormone on acute lung injury in endotoxemic rats 总被引:3,自引:0,他引:3
C. Yi S. R. Wang S. Y. Zhang S. J. Yu C. X. Jiang M. H. Zhi Y. Huang 《Inflammation research》2006,55(11):491-497
995.
Pettit SJ Ali S O'Flaherty E Griffiths TR Neal DE Kirby JA 《Clinical and experimental immunology》1999,116(1):48-56
Transitional cell carcinomas (TCC) of the urinary bladder are known to express proteins which can yield potentially immunogenic peptide epitopes for expression in the context of cell surface class I or class II MHC antigens. However, additional costimulatory ligands must also be expressed before such a cell might directly induce full activation and proliferation of resting, antigen-specific T lymphocytes. Intravesical therapy might be used to manipulate T cell costimulation in order to promote specific rejection of TCC cells. This in vitro study examined the potential of such a strategy by transfection of the prototypical TCC line J82 with the important costimulatory molecules CD80 (B7-1) and CD86 (B7-2). Untransfected J82 cells expressed class I and II MHC antigens, a range of cell adhesion molecules, though did not induce T cell proliferation in a robust, allogeneic co-culture system. Transfected J82 cells expressed CD80 or CD86 at levels comparable to an antigen-presenting B cell line. Furthermore, functional surface expression of CD80 and CD86 was demonstrated in a mitogen-dependent assay of costimulation. However, neither CD80+ nor CD86+ transfectant J82 cells could induce significant proliferation of antigen-specific CD4+ T cells. Further analysis showed that bystander J82 cells could inhibit independent T cell activation in an effect dependent on direct cell contact. This inhibitory effect was associated with increased cell death in the responding lymphocyte population and is concordant with surface expression of CD95L by the J82 cell line. 相似文献
996.
In Xenopus, localized factors begin to regionalize embryonic fates prior to the inductive interactions that occur during gastrulation. We previously reported that an animal-to-vegetal signal that occurs prior to gastrulation promotes primary spinal neuron fate in vegetal equatorial (C-tier) blastomere lineages. Herein we demonstrate that maternal mRNA encoding noggin is enriched in animal tiers and at low concentrations in the C-tier, suggesting that the neural fates of C-tier blastomeres may be responsive to early signaling from their neighboring cells. In support of this hypothesis, experimental alteration of the levels of Noggin from animal equatorial (B-tier) or BMP4 from vegetal (D-tier) blastomeres significantly affects the numbers of primary spinal neurons derived from their neighboring C-tier blastomeres. These effects are duplicated in blastomere explants isolated at cleavage stages and cultured in the absence of gastrulation interactions. Co-culture with animal blastomeres enhanced the expression of zygotic neural markers in C-tier blastomere explants, whereas co-culture with vegetal blastomeres repressed them. The expression of these markers in C-tier explants was promoted when Noggin was transiently added to the culture during cleavage/morula stages, and repressed with the transient addition of BMP4. Reduction of Noggin translation in B-tier blastomeres by antisense morpholino oligonucleotides significantly reduced the efficacy of neural marker induction in C-tier explants. These experiments indicate that early anti-BMP signaling from the animal hemisphere recruits vegetal equatorial cells into the neural precursor pool prior to interactions that occur during gastrulation. 相似文献
997.
Association of the envelope glycoproteins of influenza virus with liposomes--a model study on viral envelope assembly. 总被引:9,自引:0,他引:9
Envelope glycoproteins of virus N (an avian influenza virus) were artificially associated with liposomes, using octylglucoside as detergent which could be readily removed by dialysis. The prepared liposomes, about 0.1-1 μm in diameter, contained specific hemagglutinin and neuraminidase activities. The total amounts of proteins incorporated into liposomes were about the same irrespective of the lipid composition. Similarly, the neuraminidase activity of liposomes remained unchanged by altering lipids. However, the hemagglutinating and cell-adsorbing properties of liposomes varied greatly depending on the composition of lipids. As both lipid and protein components can be altered, the present system may be elaborated for the study of protein-lipid interactions and functions of viral membranes. 相似文献
998.
Rh proteins vs Amt proteins: an organismal and phylogenetic perspective on CO2 and NH3 gas channels.
Rh (Rhesus) proteins are homologues of ammonium transport (Amt) proteins. Physiological and structural evidence shows that Amt proteins are gas channels for NH(3), but the substrate of Rh proteins, be it CO2 as shown in green alga, or NH3/NH4+ as shown in mammalian cells, remains disputed. We assembled a large dataset generated of Rh and Amt to explore how Rh originated from and evolved independently of Amt relatives. Analysis of this rich data implies that Rh was split from Amt first to emerge in archaeal species. The Rh ancestor underwent divergence and duplication along speciation, leading to neofunctionalization and subfunctionalization of the Rh family. The characteristic organismal distribution of Rh vs. Amt reflects their early separation and subsequent independent evolution: they coexist in microbes and invertebrates but do not in fungi, vascular plants or vertebrates. Rh gene-duplication was prominent in vertebrates: while epithelial RhBG/RhCG displayed strong purifying selection, erythroid Rh30 and RhAG experienced different episodes of positive selection in each of which adaptive evolution occurred at certain time points and in a few codon sites. Mammalian Rh30 and RhAG were subject to particularly strong positive selection in some codon sites in the lineage from rodents to human. The grounds of this adaptive evolution may be driven by the necessity to increase the surface/volume ratio of biconcave erythrocytes for facilitative gas diffusion. Altogether, these results are consistent with Rh proteins not being the orthologue of Amt proteins but having gained the function for CO2/HCO3- transport, with important roles in systemic pH regulation. 相似文献
999.
大鼠内毒素休克肝线粒体Ca^2+,Mg^2+含量变化与线粒体损伤 总被引:5,自引:1,他引:5
本文在大鼠内毒素休克模型上,观察了肝线粒体结构和功能与Ca^2+,Mg^2+含量变化的关系。结果发现:休克动物肝组织和线粒体的Ca^2+浓度升高,Mg^2+浓度下降与正常对照组相比有非常显著性差异;用图像分析仪定量分析显示线粒体结构明显受损,线粒体标志酶之一-琥珀酸脱氢酶(SDH)活性明显下降,本文认为组织和线粒体内Mg^2+/Ca^2+比值下降是休克细胞不可逆损伤重要因素之一。 相似文献
1000.