Measuring receptor/ligand interaction at the single-bond level: experimental and interpretative issues

There is increased interest in measuring kinetic rates, lifetimes, and rupture forces of single receptor/ligand bonds. Valuable insights have been obtained from previous experiments attempting such measurements. However, it remains difficult to know with sufficient certainty that single bonds were indeed measured. Using exemplifying data, evidence supporting single-bond observation is examined and caveats in the experimental design and data interpretation are identified. Critical issues preventing definitive proof and disproof of single-bond observation include complex binding schemes, multimeric interactions, clustering, and heterogeneous surfaces. It is concluded that no single criterion is sufficient to ensure that single bonds are actually observed. However, a cumulative body of evidence may provide reasonable confidence. © 2002 Biomedical Engineering Society. PAC2002: 8715Kg, 8715By, 8716-b     

脉冲磁场对肝癌细胞株HepG2细胞增殖和分化的影响

目的　研究低频脉冲磁场对肝癌细胞株HepG2细胞增殖和分化的影响。方法　 2种频率不同场强相同的低频脉冲磁场处理HepG2细胞 ,以 2 对磺酸基苯基 3 ( 4 ,5 二甲基噻唑 ) 5 ( 3 羧甲氧基苯基 ) 二氢四唑嗡盐 (MTS)方法检测细胞的增殖情况 ,酶联免疫法测定HepG2细胞甲胎蛋白的分泌量。结果　 80Hz、1.5 5mT磁场分别处理HepG2细胞 1、4、8、12和 2 4h ,对HepG2细胞的增殖均无明显影响 ,差异无显著性 (P >0 .0 5 )。 16Hz脉冲磁场分别处理HepG2细胞 1、4、8和 2 4h ,对HepG2细胞的增殖和甲胎蛋白 (AFP)的分泌量均无明显影响 ,差异无显著性 (P >0 .0 5 )。结论　本研究没有观察到 16、80Hz脉冲磁场对肝癌细胞株HepG2的增殖和特征蛋白 (AFP)分泌存在“窗口”效应     

Colorectal cancer screening for the natural population of Beijing with sequential fecal occult blood test: a multicenter study

Objective To assess the prevalence of colorectal cancer(CRC)in Beijing and the reliability or the sequential fecal occult blood test(SFOBT)for CRC screening.Methods Of the natural population(48 100 persons)in several Beijing communities,we screened 26 827 persone with age over 30 using the SFOBT screening program,Guaiacum Fecal Occult Blood Test(GFOBT),lmmuno Fecal Occult Blood Test(IFOBT),and colonoscopies.Results The screening rate of the population was 74%.The positive rate of SFOBT was 5.6%.The prevalence of CRC in the entire population of Beijing was therefore calculated to be 36.57/10^5.Of 12 CRC detected patients,4 cases were in stage DukesA (33.33%),7 cases in stage Dukes B(58.33%),only 1 case(8.34%)in stage Dukes C.Conclusions The prevalence of CRC in Beijing is one of the highest in China,Individuals at high risk for CRC or those over 50 years of age should be considered as primary candidates for screening,SFOBT screening is a cost-effective and reliable method for early detection of CRC.     

Fas／FasL基因在11酸睾酮诱导恒河猴无精子症或少精子症中的作用

目的：研究凋亡相关基因Fas/FasL在11酸睾酮诱导无精子症或少精子症的作用。方法：TUNEL用于检测睾丸细胞的凋亡信号。免疫组化和Western blot用于对这些凋亡相关基因所表达的蛋白进行定量或定性分析。结果：11酸睾酮处理后,生精细胞的凋亡信号和Fas/FasL蛋白的表达呈现时间依赖性方式增强,至第30天达到最大值。结论：Fas系统可能参与启动和调节11酸睾酮诱导的生精细胞的凋亡。     

Controlled release of antifungal drug terbinafine hydrochloride from poly(N-vinyl 2-pyrrolidone/itaconic acid) hydrogels

In the present study, a new microwave-enhanced dehydration and solvent washing purification of penicillin G sulfoxide technique has been developed. The results show that microwave irradiation can dehydrate penicillin G sulfoxide from a water content of 14–26 to below 0.5% in 40–60 min in N₂ or air. After washing with ethyl acetate to remove impurities and residual water, the penicillin G sulfoxide can be used to synthesize cephalosporanic acid. The recovery of cephalosporanic acid was equal to and the purity of cephalosporanic acid was higher by 2% than that of the current dehydration technique. FTIR spectroscopy was used to study the process of microwave-enhanced dehydration and solvent washing purification of penicillin G sulfoxide.     

聚合物分子量对热致相分离法制备聚乙烯微孔滤膜的影响

选取不同分子量的聚乙烯/二苯醚作为聚合物稀释剂体系,通过浊点及结晶温度绘制了体系的热力学相图;并在不同淬冷温度下,通过热致相分离法制备了聚乙烯微孔滤膜。讨论了聚合物分子量及淬冷温度对成膜孔结构的影响。结果表明:聚合物的分子量不仅影响微孔滤膜断面的孔径,还影响其形态和结构。     

泻下药和解表药的现代药理解释

 目的在中药现代化的进程中,对中医药体系中的传统药效的现代药理学解释是一项有深远意义的工作。本实验设计了3种方法,在总体上对中药的传统药效与中药的现代药理活性进行对比分析,从中发现规律,对被研究的中药药效给出言之有据的解释。方法收集大量中药传统药效、中药现代药理活性和中药所含活性化合物现代药理活性数据,通过统计方法寻找特定中药药效类别(泻下和解表)的现代药理学的特征,从而得到其现代药理学解释。结果使用的3种方法都能够给出与2种药效相关的现代药理活性。汇总3种结果得到,泻下与导泄、兴奋胃肠平滑肌、止血和利尿4种药理活性相关;解表与抗凝血/抗血栓、止痛、解热3种药理作用相关。3种方法比较,共有化合物方法结果比较好。结论对大量中药的传统药效和它们的现代药理活性数据进行比对分析,可以得到中药药效的现代药理解释。这种方法可以推广到对其他中药传统药效的研究中,对中医药的现代化进程起到推动作用。     

补肾益脑片对加速衰老小鼠P10/Ta小鼠神经细胞衰老相关基因表达的调节

 目的研究补肾益脑片抗衰老的分子机制。方法应用DDRT-PCR研究补肾益脑片提取物对SAM(senescence-acceler-ated mouse)P10/Ta小鼠原代培养的神经细胞基因表达的影响。结果发现了10个差异表达片段,分别与下列基因或转录产物同源:小鼠mRNA克隆IMAGE4235872,小鼠RIKENcDNA A730024A03基因mRNA,小鼠血清淀粉样蛋白A3(SAA3),异种核蛋白A0(HNRNP A0),小鼠OVCA1(Dph211)mRNA,蛋白酶体26S亚单位,ATP依赖线粒体RNA螺旋酶,小鼠线粒体核蛋白S31(Mrps31),小鼠CX43 gene,小鼠tRNA-Ile.结论补肾益脑片可能通过影响与衰老相关的基因表达发挥抗衰老作用。     

基于熵的复杂系统分划方法在动脉硬化闭塞症中医证候量化诊断标准研究中的应用

目的:建立动脉硬化闭塞症(Ⅰ、Ⅱ期)中医证候量化诊断标准(包括量化诊断标准和程度分级标准)。方法:根据文献调研、专家咨询、临床流行病学调查获得动脉硬化闭塞症(Ⅰ、Ⅱ期)的四诊资料,以基于熵的复杂系统分划方法筛选症状,确定症状对证候的贡献分值,以ROC曲线分析确定证候诊断阈值。结果:建立了动脉硬化闭塞症(Ⅰ、Ⅱ期)的量化诊断标准,并对量化诊断标准进行检验,具有良好的灵敏度和特异度,最后建立了程度分级标准。结论:基于熵的复杂系统分划方法可以用于中医证候的量化诊断研究,具有较好的诊断效能。     

急性脑卒中67例血气变化及酸碱平衡临床分析

为探讨急性脑卒中后血气及酸碱平衡变化.本文选择了经头颅CT证实的脑出血。蛛网膜下出血(SAH)及脑梗塞患者67侧,于发病后24—48小时进行血气分析.发现脑出血>30ml和出血破入脑室。SAH及大面积脑梗塞患者中60％为呼碱并代酸及呼碱型三重碱失衡(TADD),还发现混合性酸碱失衡死亡率比单纯性的和正常血气要高(P<0.05).生存组与死亡组PaCO_2和HCO_3值比较有显著性差异(P<0.05),提示酸碱失衡的严重程度同血管性病的性质和大小及预后有较大关系,PaCO_2降低程度与HCO_3值和死亡率呈正相关.