胸内正压对正常人左室功能影响及其力学原理

目的：探讨胸内正压对正常人左室射血及充盈的影响及其力学原理。方法：超声心动图观测30例正常人初始时与标准乏氏动作张力期10s时左室舒张末容积（LVEDV）、左室收缩末容积（LVESV）、每搏量（SV）、射血分值（EF）、流入道血流速度（E峰、A峰）、E／A值、二尖瓣环舒张早期运动速度（e）及舒张早期充盈压（E/e）的变化。结果：与初始时比较,标准乏氏动作张力期LVEDV、LVESV及SV减低而心率（陬）增快（P均〈0．001）,EF值增加,但无统计学意义（P〉0．05）;E峰与E／A值减低（P均〈O．05）;e没有变化（P〉0．05）．E／e值减低（P〈O．05）。结论：胸内正压对左室游离壁的力学作用促进了左室收缩运动而阻碍了左室舒张运动,会引起EF值增加,E峰及E／A值减低;2,胸内正压降低了肺静脉系统与心脏的跨壁压力,增加了血流阻力也是导致肺静脉系统与左室血液回流减少．E峰减低．E／e值减低的一个原因。     

丝素蛋白/羟基磷灰石复合物对磷酸钙骨水泥性能的影响

目的：磷酸钙骨水泥（Calcium phosphate cement,CPC）以其诸多优点正得到了越来越多的应用,但其较差的力学性能表现也限制了它的使用范围。本研究目的在于改善磷酸钙骨水泥的力学性能,同时评估改性后的磷酸钙骨水泥的其他性能。方法：通过丝素蛋白（Silk fibroin,SF）的矿化自组装方法制备丝素蛋白／羟基磷灰石复合物（silk fibroin/hydroxyapitite composite, SF/HA）。按照1％、2％、3％、4％的质量分数加入磷酸钙骨水泥中,与磷酸钙骨水泥组对比。比较内容包括力学强度、抗渍散性能及细胞毒性。结果：以丝素蛋白溶液为液相组的磷酸钙骨水泥强度大约为35MPa。随后随着添加丝素蛋白／羟基磷灰石复合物的质量分数从1％增至3％,磷酸钙骨水泥的强度逐渐增加（P〈0．05）,最高约至45MPa。而当丝素蛋白／羟基磷灰石的质量分数达到4％时,磷酸钙骨水泥的强度较质量分数3％组小幅度下降至43MPa（P〈0．05）。以丝素蛋白溶液作为液相时,磷酸钙骨水泥的抗溃散能力也得到了加强。在MTT法测定细胞活力的对照实验中,无论是加入丝素蛋白溶液或丝素蛋白／羟基磷灰石复合物,都未观察到细胞毒性。结论：在磷酸钙骨水泥中加入3％质量分数的丝素蛋白／羟基磷灰石复合物,能显著提高磷酸钙骨水泥的抗压强度。而丝素蛋白溶液作为液相可改善磷酸钙骨水泥的抗溃散能力。同时,丝素蛋白和丝素蛋白／羟基磷灰石复合物都不表现出细胞毒性。更理想的力学强度和更强的抗溃散能力,大大扩展了磷酸钙骨水泥的应用范围。     

TNFR1 promotes tumor necrosis factor-mediated mouse colon epithelial cell survival through RAF activation of NF-kappaB

Tumor necrosis factor (TNF) is a therapeutic target in the treatment of inflammatory bowel disease; however, the exact role of TNF signaling in the colon epithelium remains unclear. We demonstrate that TNF activation of TNF receptor (R)1 stimulates both pro- and anti-apoptotic signaling pathways in the colon epithelium; however, TNFR1 protects against colon epithelial cell apoptosis following TNF exposure. To investigate anti-apoptotic signaling pathways downstream of TNFR1, we generated an intestinal epithelium-specific Raf knock-out mouse and identified Raf kinase as a key regulator of colon epithelial cell survival in response to TNF. Surprisingly, Raf promotes NF-kappaB p65 phosphorylation, independent of MEK signaling, to support cell survival. Taken together, these data demonstrate a novel pathway in which Raf promotes colon epithelial cell survival through NF-kappaB downstream of TNFR1 activation. Thus, further understanding of colon epithelial cell-specific TNFR signaling may result in the identification of new targets for inflammatory bowel disease treatment and define novel mediators of colitis-associated cancer.     

Genomic evidence for population‐specific responses to co‐evolving parasites in a New Zealand freshwater snail

Reciprocal co‐evolving interactions between hosts and parasites are a primary source of strong selection that can promote rapid and often population‐ or genotype‐specific evolutionary change. These host–parasite interactions are also a major source of disease. Despite their importance, very little is known about the genomic basis of co‐evolving host–parasite interactions in natural populations, especially in animals. Here, we use gene expression and sequence evolution approaches to take critical steps towards characterizing the genomic basis of interactions between the freshwater snail Potamopyrgus antipodarum and its co‐evolving sterilizing trematode parasite, Microphallus sp., a textbook example of natural coevolution. We found that Microphallus‐infected P. antipodarum exhibit systematic downregulation of genes relative to uninfected P. antipodarum. The specific genes involved in parasite response differ markedly across lakes, consistent with a scenario where population‐level co‐evolution is leading to population‐specific host–parasite interactions and evolutionary trajectories. We also used an F_ST‐based approach to identify a set of loci that represent promising candidates for targets of parasite‐mediated selection across lakes as well as within each lake population. These results constitute the first genomic evidence for population‐specific responses to co‐evolving infection in the P. antipodarum‐Microphallus interaction and provide new insights into the genomic basis of co‐evolutionary interactions in nature.     

Energy Crop and Biotechnology for Biofuel Production

Selection of energy crops is the first priority for large-scale biofuel production in China. As a major topic, it was extensively discussed in the Second International Symposium on Bioen-     

尿毒症皮肤瘙痒患者采取腹膜透析与血液透析治疗的效果探究

目的：探究尿毒症皮肤瘙瘁患者采取腹膜透析与血液透析治疗的临床效果,并为该病的临床治疗提供经验积累。方法：选取我院肾内科于2005年1月-2012年12月收治的52例尿毒症皮肤瘙痒患者,利用随机数字表法进行分组,分别设为研究组和对照组。其中对照组实施血液透析治疗,而研究组开展腹膜透析治疗。记录两组在治疗前和治疗后第8周末血生化客观指标及皮肤瘙痒程度,并做好对比。结果：两组在治疗前的皮肤瘙痒评分、β2-MG、PTH、p3,BUN、SCr值差异无统计学意义（P〉0．05）;治疗后,研究组皮肤瘙瘁评分为（3．4±0．8）分,对照组为（5．8±0．9）分,差异有统计学意义（P〈0．05）。治疗后,研究组β2-MG、PTH及Ps．均低于对照组,差异有统计学意义（P〈0．05）。结论：尿毒症皮肤瘙痒患者的主要致敏因子为大中分子,采取腹膜透析能够有效清除大分子物质,进而达到瘙痒程度的有效改善。     

A framework for integrating the songbird brain

Biological systems by default involve complex components with complex relationships. To decipher how biological systems work, we assume that one needs to integrate information over multiple levels of complexity. The songbird vocal communication system is ideal for such integration due to many years of ethological investigation and a discreet dedicated brain network. Here we announce the beginnings of a songbird brain integrative project that involves high-throughput, molecular, anatomical, electrophysiological and behavioral levels of analysis. We first formed a rationale for inclusion of specific biological levels of analysis, then developed high-throughput molecular technologies on songbird brains, developed technologies for combined analysis of electrophysiological activity and gene regulation in awake behaving animals, and developed bioinformatic tools that predict causal interactions within and between biological levels of organization. This integrative brain project is fitting for the interdisciplinary approaches taken in the current songbird issue of the Journal of Comparative Physiology A and is expected to be conducive to deciphering how brains generate and perceive complex behaviors.