复方丹参注射液对急性水肿型胰腺炎患者可溶性粘附分子水平的影响

目的:研究复方丹参注射液对急性水肿型胰腺炎患者外周血粘附分子水平的影响,探讨复方丹参注射液治疗急性胰腺炎的机制。方法:采用复方丹参注射液结合西药治疗32例急性水肿型胰腺炎患者(治疗组),取常规西药治疗的35例急性水肿型胰腺炎患者(治疗对照组)作为对比观察,并于治疗前后检测患者血液中粘附分子P-选择素(P-sel)和细胞间粘附分子-1(ICAM-1)水平。结果:治疗组的腹痛缓解时间、尿淀粉酶恢复时间和平均住院时间均短于治疗对照组(P<0.05或0.01),临床疗效也优于治疗对照组(H c=5.7902,P<0.05)。治疗前治疗组和治疗对照组的P-sel、ICAM-1比较差异无显著性(P>0.05),治疗后治疗组的P-sel下降较明显,与治疗对照组比较差异有非常显著性(P<0.01),两组治疗后ICAM-1水平差异未见显著性(P>0.05)。结论:复方丹参注射液结合西药治疗对急性胰腺炎有显著疗效,可能与复方丹参注射液能调节免疫细胞粘附分子表达,抑制炎症细胞聚集,进而抑制炎症反应有关。     

溃疡性结肠炎患者C反应蛋白、炎性细胞因子和粘附分子水平的检测及其临床意义

目的：观察溃疡性结肠炎(UC)患者外周血C反应蛋白(CRP)、炎性细胞因子IL-6、TNF—α和牯附分子P-选择素(P-sel)、细胞间粘附分子-1(ICAM—1)水平的变化,了解C反应蛋白、炎性细胞因子和牯附分子在UC发病中的作用。方法：采用全自动蛋白分析仪和ELISA法分别检测28例活动期和13例缓解期UC患者和30例健康人(对照组)的外周血CRP、细胞因子和粘附分子水平。结果：活动期UC患者外周血的CRP、IL-6、TNF—α、P—sel、ICAM—1水平均高于对照组和缓解组。缓解组患者CRP、IL-6、TNF—α、P—sel和ICAM—1与对照组比较差异无统计学意义。活动期UC患者CRP含量与炎性细胞因子及粘附分子的水平呈正相关。结论：UC患者血中炎性细胞因子、粘附分子和CRP水平升高,在UC发病过程中有一定的作用;检测CRP可作为UC病情判断和疗效评估的指标。     

Waterlogged molecules

Measurements of vapor pressures over their aqueous solutions indicate that organic compounds show profound differences in hydrophilic character. These differences are of such magnitude as to suggest an important role for changing solvation in determining free energy changes associated with metabolic transformations in water, and in governing structural equilibria of proteins and other large molecules in water. When two or more functional groups are present within the same solute molecule, their combined effects on its free energy of solvation are commonly additive. Striking departures from additivity, observed in certain cases, indicate the existence of special interactions between different parts of a solute molecule and the water that surrounds it. Similar considerations presumably apply to activated intermediates in the interconversion of biological materials.     

Thrombospondin promotes cell-substratum adhesion

The physiological role of the platelet-secreted protein thrombospondin (TSP) is poorly understood, although it has been postulated to be involved in platelet aggregation and cellular adhesion. In this report, TSP isolated from human platelets was found to promote, in vitro, the cell-substratum adhesion of a variety of cells, including platelets, melanoma cells, muscle cells, endothelial cells, fibroblasts, and epithelial cells. The adhesion-promoting activity of TSP was species independent, specific, and not due to contamination by fibronectin, vitronectin, laminin, or platelet factor 4. The cell surface receptor for TSP is protein in nature and appears distinct from that for fibronectin.     

Reactions of oriented molecules

Beams of oriented molecules have been used to directly study geometrical requirements in chemical reactions. These studies have shown that reactivity is much greater in some orientations than others and demonstrated the existence of steric effects. For some reactions portions of the orientation results are in good accord with traditional views of steric hindrance, but for others it is clear that our chemical intuition needs recalibrating. Indeed, the information gained from simultaneously orienting the reactants and observing the scattering angle of the products may lead to new insights about the detailed mechanism of certain reactions. Further work must be done to extend the scope and detail of the studies described here. More detailed information is needed on the CH(3)I reaction and the CF(3)I reaction. The effects of alkyl groups of various sizes and alkali metals of various sizes are of interest. In addition, reactions where a long-lived complex is formed should be studied to see if orientation is important. Finally, it would be of interest to apply the technique to the sort of reactions that led to our interest in the first place: the S(N)2 displacements in alkyl halides where the fascinating Walden inversion occurs.     

Bose-Einstein condensation of molecules

We report on the Bose-Einstein condensation of more than 10(5) Li2 molecules in an optical trap starting from a spin mixture of fermionic lithium atoms. During forced evaporative cooling, the molecules are formed by three-body recombination near a Feshbach resonance and finally condense in a long-lived thermal equilibrium state. We measured the characteristic frequency of a collective excitation mode and demonstrated the magnetic field-dependent mean field by controlled condensate spilling.     

Nucleation on photoexcited molecules

On irradiation with light of suitable wavelength and intensity, certain organic compounds, even at very low concentrations, cause very efficient nucleation of supersaturated vapors. A mechanism is suggested to account for this phenomenon. Nuclei containing only a few photoexcited molecules are responsible for the nucleation.     

干细胞与肿瘤研究进展

肿瘤是危害人类健康的恶性疾病,近年来越来越多证据显示肿瘤与干细胞有着密切的关系。肿瘤可能是干细胞在异常微环境中差异分化的结果。它与正常干细胞有相似的表面标志和生化特点。在此,综述了干细胞与肿瘤发生的关系及干细胞工程在肿瘤治疗中的应用前景,旨在为肿瘤发生发育的研究及干细胞在肿瘤治疗方面的应用提供理论依据。     

Adhesion: molecules and mechanics

There is a difference between adhesion at the molecular level and adhesion in engineering. There is no doubt that molecules of solid materials stick together and can be separated mechanically. The problem is explaining the connection between molecular attractions and mechanical measurements. False ideas such as keying and gluing require critical assessment because they confuse molecules and mechanics. Mechanisms such as adhesive hysteresis, stringing, and clustering deserve evaluation. A rational theory of these phenomena should be based on the theoretical concept of reversible work of adhesion and on the measured quantity of adhesive energy, which includes the extra energy required to restructure the interface as surfaces move.     

Chemistry. Beyond platonic molecules

Molecular motion is influenced by quantum mechanics, which thus affect molecular properties such as their reactivity and the ease with which they isomerize. In his Perspective, Bowman describes recent theoretical advances that allow accurate quantum mechanical calculation of molecular motions for ever larger systems.