CD44V6在鼻咽癌转移中的意义

目的:探讨CD44V6在鼻咽癌细胞转移中的作用。方法:应用CD44V6单克降抗体免疫组化染色后统计分析。结果:CD44V6分子在正常鼻咽鳞状上皮、鼻咽慢性炎症增生的鳞状上皮胞膜或/和胞质中表达,表层细胞表达弱或不表达,周围间质为阴性反应。CD44V6在鼻咽癌组织中阳性表达率(33.3%)比正常组织明显减少;其与淋巴结转移有关(P<0.05),与临床分期无关(P>0.05)。结论:CD44V6蛋白在鼻咽癌转移过程中以下行调节方式表达,反映其正常表达可能阻止肿瘤对周围组织的浸润。     

End-group modified retro-inverso isomers of tripeptide oxytocin analogues: binding to neurophysin II and enhancement of its self-association properties

The importance of peptide backbone structure in peptide/protein recognition events has been tested evaluating the binding properties of end-group modified retro-inverso isomers of MYF and LYF amides, tripeptides able to mimic oxytocin in binding neurophysin II and in potentiating its self-association. The isomers, topochemically related to their parent peptides, have been prepared respectively from all-D N-acetyl-FYM and N-acetyl-FYL amides via the Hofmann-type rearrangement mediated by iodobenzene bis-trifluoroacetate. Retro-inverso isomers recognised neurophysin II with similar affinity as the parent peptides, as determined by analytical affinity chromatography on columns prepared immobilising neurophysin II on preactivated supports. In addition, their effect on neurophysin II self-association was similar to the tripeptide oxytocin analogues, potentiating neurophysin II dimerization to the same extent, as evaluated by solid-phase binding assays on microtiter plates coated with neurophysin II. Recognition specificity of retro-inverso isomers was further demonstrated by their inhibitory effect on the interaction between neurophysin II and oxytocin tripeptide analogues. Results suggest that only the proper orientation of the α-amino group and of the side chains plays a dominant role in the binding of tripeptide analogues to neurophysin II and potentiation of its self-association, while the peptide backbone topology has little influence on the recognition process.     

HPLC法测定盐酸莫西沙星中R-异构体含量

目的:建立HPLC法对盐酸莫西沙星S-和R-异构体进行拆分并测定其中R-异构体含量。方法:采用AD-H手性柱(DAICEL CHIRALPAK,250 mm×4.6 mm,5μm),流动相为正己烷-异丙醇-二乙胺-乙酸(85∶15∶0.2∶0.1),流速1.0 mL.min-1,柱温35℃,检测波长293 nm;进样量10μL。结果:盐酸莫西沙星异构体之间的分离度为3.4,R-异构体的线性范围为0.54～5.40μg.mL-1(r=0.9995),检测限为1.1 ng,平均回收率(n=9)为99.2%。结论:该方法操作简便,结果准确,可用于盐酸莫西沙星中R-异构体含量测定。     

Inductive effects on the structure of proline residues

4(S)-Hydroxyproline (Hyp) residues constitute about l0%, of most forms of collagen, the most abundant protein in vertebrates. X-Ray diffraction analysis was used to ascertain how the structure of proline residues is affected by the inductive effect elicited by the hydroxyl group of Hyp residues. N-Acetylproline methylester (1), N-acetyl-4(S)-hydroxyproline methylester (2) and N-acetyl-4(S)-fluoroproline methylester (3) were synthesized, and their crystalline structures were determined at high resolution. The amide bond of crystalline 1 was in the cis conformation. which is the minor isomer in solution, and the pyrrolidine ring of 1 had Cγ-endo pucker. In crystalline 2 and 3 the arnide bonds were in the trans conformation, and the pyrrolidine rings had Cγ-exo pucker. The lengths of the bonds between sp³-hybridized carbon atoms in the pyrrolidine ring were significantly shorter in 2 and 3 than in 1, as was predicted by ab initio molecular orbital calculations at the RHF/3-21G level of theory. No significant change in bond length was observed in the other bonds of 1, 2 or 3. The pyramidylization of the nitrogen atom increased dramatically in the order: 1<2<3. Together, these results indicate that electron-withdrawing substituents in the 4-position of proline residues can have a significant influence on the structure of these residues. In particular, the change in pyramidylization suggests that such substituents increase the sp3-character of the prolyl nitrogen atom and could thereby alter the rate of prolyl peptide bond isomerization.     

醋高诺酮肟的合成及其顺、反式异构体的分离

本文对文献报道的醋高诺酮肟（Norgestlmate）的多种合成方法进行了比较。设计更简单的合成方法，合成了醋高诺酮肟。在合成方法及合成的总收率上均较文献报道为优，合成所得的醋高诺酮肟经柱层析分离、提纯得到了顺、反式的醋高诺酮肟。为完成顺、反式醋高诺酮肟异构体的药效学研究提供了样品。顺、反式异构体的药效学研究，将为醋高诺酮肟作为避孕药，提供科学依据。     

Chemical analysis of monomers in epoxy resins based on bisphenols F and A

Diglycidyl ether of bisphenol A (DGEBA) is the monomer and most important contact allergen in epoxy resin(s) based on bisphenol A (DGEBA-R). Both thin-layer chromatography (TLC) and high-pressure liquid chromatography (HPLC) methods are available for the analysis of products containing DGEBA-R. With respect to detection and quantification, epoxy resins of the bisphenol F-type, i.e. epoxy resins containing the isomers of diglycidyl ethers of bisphenol F (DGEBF), are not as well investigated as DGEBA-R. The isomers of DGEBF are p,p'-DGEBF, o,p'-DGEBF and o,o'-DGEBF. Both p,p'-DGEBF and o,p'-DGEBF have been shown to be contact allergens in humans, and all 3 isomers are sensitizers in the guinea pig maximization test. We aimed (i). to develop HPLC methods for separation and purification of the individual DGEBF isomers, (ii). to detect and quantify the DGEBF isomers in epoxy resins of the bisphenol F-type and (iii). to evaluate and develop the TLC as a method for the detection of the DGEBF monomers. We found the total content of the DGEBF isomers in the investigated epoxy resins of the bisphenol F-type to vary from 17.0 to 81.7% w/w. Some of them also contained 0.1-2.4% w/w DGEBA. The HPLC method showed a sensitivity that was 2000-20 000x higher than that obtained with the TLC method for the DGEBF monomers. We concluded that the range of the DGEBF isomer content in epoxy resins of the bisphenol F-type is approximately the same as the monomer content in liquid compared to solid DGEBA-R. The relevance of contact allergy to DGEBA-R can remain unrecognized if the suspected product is an epoxy resin of the bisphenol F-type, which is analysed with the TLC method.     

梯度洗脱高效液相色谱法检测他克莫司有关物质

 目的建立他克莫司有关物质检测的方法,并观察样品在不同溶剂中可能存在的异构体的转化情况,同时液-质联用技术进一步确证有关物质。方法以辛烷基硅烷键合硅胶为填充剂,以0.02mol·L^-1磷酸二氢钾(pH3.5)与乙腈为流动相梯度洗脱;检测波长为210nm,柱温60℃;利用液-质联用技术确证可能存在的杂质。结果样品在质子性的溶剂中确实存在异构体的转化且该转化能达到平衡,但在乙腈溶剂中基本无转化,该溶剂可作为他克莫司有关物质的测定溶剂,样品中的主要杂质为发酵副产物。结论本法简便、准确,重复性好,能有效地检测样品中的有关物质。     

胶束毛细管电泳法分离维A酸与异维A酸

目的研究应用高效毛细管电泳法分离维A酸与异维A酸,考察不同电泳条件下胶束毛细管电泳的分离行为。方法采用弹性石英毛细管柱,柱温为35℃,以20 mmol.L-1去氧胆酸钠溶-液20 mmoL.L-1硼砂溶液(pH 10.5)-乙腈(1∶1∶1)为运行缓冲液,运行电压30 kV,检测波长340 nm。结果在选定的电泳条件下,维A酸与异维A酸的最低检测浓度均为1.2μg.ml-1。结论本法柱效高,分离度好,是分离维A酸与异维A酸顺反异构体较为理想的方法。     

HPLC分离测定那格列奈顺式异构体杂质的方法学研究

目的　建立那格列奈顺反式异构体分离测定的HPLC。方法　采用C18柱 ,在室温下 ,以 (A)乙腈 (B) 0 .0 3mol·L-1磷酸盐缓冲液 (pH 2 .5 ) (6 5∶35 )为流动相 ,检测波长 2 14nm ,进样量 10 μL。结果　那格列奈顺反式异构体的分离度大于 1.5 ,最小检出限为 0 .0 6 μg·mL-1,定量限为 0 .18μg·mL-1。结论　本法可有效分离测定顺式体。     

恩他卡朋的合成

目的 用改进的方法合成及纯化恩他卡朋，提高产率。方法 以3，4-二羟基-5-硝基苯甲醛和N，N-二乙基-氰基酰胺为原料，在弱碱性条件下经过克脑文格尔反应生成2-氰基-N，N-二乙基-3-（3，4-二羟基-5-硝基苯基）丙烯酰胺，然后对顺反异构体进行纯化，最后进行红外光谱分析，元素分析，X-射线粉末衍射分析。结果 所合成的终产物图谱与标品一致。