离子交换色谱法测定去甲基斑蝥素乳剂的含量

目的:建立离子交换色谱法测定去甲基斑蝥素乳剂含量的方法.方法:采用Hypersil SAX色谱柱(250mm×4.6 mm,5 μm),以0.3%磷酸-甲醇(75:25)为流动相,流速0.6 mL·min-1;检测波长:210 nm;柱温:室温.结果:在本色谱条件下测定去甲基斑蝥素线性范围为2～80 μg·mL-1,相关系数r=0.999 9;高、中、低3个浓度的平均日内精密度RSD值分别为0.41%,0.46%和0.57%,日间精密度RSD分别为4.2%,6.2%和4.5%(n=5),样品测定方法回收率平均为98.9%,最低检测浓度为0.05 μg·mL-1.结论:本方法简便快捷、灵敏度高、重现性好.     

Monoliths with chiral surface functionalization for enantioselective capillary electrochromatography

The state-of-the-art in CEC enantiomer separations with monolithic capillary columns is comprehensively reviewed. The various types of monolithic columns comprising in situ organic polymer monoliths, molecularly imprinted polymer (MIP) monoliths, silica monoliths and monoliths made from particles are discussed with a focus on materials’ synthesis, chemistry and properties as well as column aspects. Monolithic MIP-type porous layer open-tubular (PLOT) columns are treated herein as well. From this survey of the literature, the authors come to the conclusion that monolithic silica capillaries appear to become the preferred column type for CEC enantiomer separations of low-molecular drugs and other chiral pharmaceuticals or chemicals.     

离子交换树脂固定果糖转移酶

超声波破碎黑曲霉细胞提取游离果糖转移酶,然后选择D201大孔阴离子交换树脂为载体,通过先吸附后交联的方法固定果糖转移酶.优化的固定化条件:加酶量为每克湿树脂400U,吸附pH值为5.0～5.5,吸附温度为30℃,吸附时间为8h,交联剂戊二醛(终)质量浓度为0.01～0.05g/dL,交联时间为8h,交联温度为1～4℃.固定化酶活最高回收率为30.2%.     

醇/水混合物在磺化聚乙烯中空纤维阴离子交换膜中的渗透汽化

通过对聚乙烯中空纤维光化学氯磺化反应,继而胺化和季胺化,制备了磺化聚乙烯中空纤维阴离子交换膜。以恒沸组成的异丙醇/水和85wt%乙醇/水为料液,测定了不同抗衡离子膜的渗透汽化性能。表明:该膜有极高的选择性,分离系数和渗透通量与抗衡离子密切相关,对卤素离子,α_W/A大小次序为I~->Br~->Cl~-;通量大小次序与之相反。三种抗衡离子膜的平衡吸收实验表明,该阴离子膜的选择渗透性不仅与醇水在膜中的溶解度有关,而且取决于平均扩散系数。     

Statins,fibrates, nicotinic acid,cholesterol absorption inhibitors,anion‐exchange resins,omega‐3 fatty acids: which drugs for which patients?

Classes of lipid lowering drugs differ strongly with respect to the types of lipids or lipoproteins they predominantly affect. Statins inhibit the de-novo synthesis of cholesterol. Consequently, the liver produces less VLDL, and the serum concentration primarily of LDL cholesterol (but, to a lesser extent, also of triglycerides) is lowered. Further, statins somewhat increase HDL cholesterol. There is abundant evidence that statins lower the rate of cardiovascular events. Cardiovascular risk reduction is the better, the lower the LDL cholesterol values achieved with statin therapy are. Some evidence is available that anion exchange resins which also decrease LDL cholesterol decrease vascular risk, too. This is not the case for the ezetimibe, which strongly lowers LDL cholesterol: its potential to decrease vascular risk remains to be proven. In contrast evidence for cardiovascular risk reduction through the mainly triglyceride lowering fibrates as well as for niacin is available. Niacin is the most potent HDL increasing drug currently available and besides increasing HDL cholesterol efficaciously lowers triglycerides and LDL cholesterol. Large ongoing trials address the decisive question whether treatment with fibrates and niacin provides additional cardiovascular risk reduction when given in addition to statin treatment.     

Soaking and cooking modify the alpha-galacto-oligosaccharide and dietary fibre content in five Mediterranean legumes

The effects of soaking and cooking on soluble sugars, alpha-galacto-oligosaccharides (α-GOS) and soluble dietary fibres (SDF) and insoluble dietary fibres (IDF) were assessed in five legumes (lentil, chickpea, fenugreek, faba bean and Egyptian faba bean). In raw seeds, total α-GOS content ranged from 2500?mg/100?g (chickpea) to over 4000?mg/100?g (fenugreek). Stachyose was predominant in fenugreek, lentil and chickpea, whereas verbascose was the main α-GOS in faba bean and Egyptian faba bean. IDF represented 69–87% of the total dietary fibres in all studied legumes, while SDF content varied noticeably. During soaking, total α-GOS content decreased between 10% (lentil and faba bean) and 40% (chickpea). In fenugreek, soaking reduced IDF and increased SDF concentration, possibly due to partial IDF solubilisation from the cell wall. Cooking further decreased α-GOS and increased total dietary fibre content. The different behaviours of these five legumes during processing illustrate the high biodiversity within legume species.     

Inhibition of ileal bile acid absorption by colestimide

BACKGROUND: Colestimide is a new type of anion-exchange resin in Japan, but its effect on bile acid absorption in the ileum has not been studied. METHODS: Absorption of ursodeoxycholate, tauroursodeoxycholate, cholate, taurocholate and taurolithocholate-sulfate in rat ileum was compared in the presence and absence of colestimide. Bile acid adsorption by colestimide in vitro was also studied. RESULTS: All bile acids were efficiently absorbed by the ileum, and the cumulative absorption during 60 min was 25-78%. The absorption of ursodeoxycholate, tauroursodeoxycholate and taurocholate was inhibited by colestimide, whereas that of cholate and taurolithocholate-sulfate was not inhibited by colestimide. Adsorption of bile acids by colestimide in vitro was higher with taurine conjugates than with the unconjugated forms. CONCLUSIONS: Colestimide was shown to be useful to inhibit the physiologically important ileal absorption of bile acid amides in vivo.     

Purification of testosterone-oestradiol-binding globulins from mammalian sera by anion-exchange high performance liquid chromatography

Testosterone-oestradiol-binding globulin (TeBG) has been isolated from serum or plasma of several species using procedures that yielded highly purified protein, but which required multiple and tedious chromatographic steps. In this report we describe a procedure for the isolation of TeBG which involves two chromatographic steps: androgen affinity chromatography followed by anion-exchange high performance liquid chromatography (anion-exchange HPLC). The purity of the final product was confirmed by silver staining following fractionation on sodium dodecyl sulphate-containing polyacrylamide gels. The size heterogeneity and specific binding activity of TeBGs purified from human, rabbit, or bull serum (or plasma) by this technique was indistinguishable from preparations obtained by conventional chromatography. The present technique shortened the entire purification procedure to about 5 working days and yielded milligram quantities of highly purified protein. Bases on our experience with serum or plasma from the human, rabbit, and bull, this approach should be suitable for isolation of TeBG from a wide range of species.     

野生型金黄色葡萄球菌肠毒素C2在E.coli中的表达和纯化研究

目的克隆金黄色葡萄球菌肠毒素C2(SEC2)基因在E.coli重组表达,纯化重组SEC2(rSEC2)并进行生物学活性分析。方法PCR获得正确编码SEC2的基因片断,构建表达质粒pET-28a-sec2在E.coliBL21中表达。利用离子交换和分子筛色谱纯化rSEC2,四甲基偶氮唑盐(MTT)法对rSEC2和天然SEC2(nSEC2)生物学活性进行分析和比较。结果可溶性rSEC2占菌体总蛋白质的40%,两步纯化后蛋白质纯度约达95%,rSEC2和nSEC2均具有显著的超抗原活性。结论成功获得与nSEC2有着类似活性的高纯度rSEC2,为进一步研究该蛋白质的抗肿瘤机理奠定物质基础。     

Is there an analytical or diagnostic advantage from including trisialo transferrin into the fraction of carbohydrate-deficient transferrin? Lessons from a comparison of two commercial turbidimetric immunoassays with the carbohydrate-deficient transferrin determination by high-performance liquid chromatography

Objectives: Carbohydrate-deficient transferrin CDT has originally been defined as the sum of isotransferrins exhibiting isoelectric point values ≥ 5.7 asialo, monosialo, and disialo transferrin but may also include at least in part trisialo transferrin when measured by modern commercial immunoassays. To examine the effects of divergently defining the analyte CDT, we compared two commercial assays yielding differently composed CDT fractions with a high-performance liquid chromatography HPLC assay commonly regarded as a reference method of CDT determination.

Methods: Relative CDT levels (CDT concentrations expressed as percent of total transferrin) were determined in 142 sera by (i) a turbidimetric immunoassay (ChronAlco I.D.) reportedly detecting asialo to disialo transferrin as CDT, (ii) an analogous assay (CDT Turbidimetric ImmunoAssay [TIA]) said to additionally include part of trisialo transferrin into the CDT fraction measured, and (iii) an anion-exchange HPLC method. Isotransferrins separated by the two commercial assays were also investigated by isoelectric focusing.

Results: Data from HPLC and isoelectric focusing indicate that the ChronAlco assay detects major parts of asialo, monosialo, and disialo transferrin as CDT while the CDT TIA yields CDT as the total of asialo, monosialo, disialo, and trisialo transferrin. When relative CDT concentrations obtained by both assays were classified as either normal or elevated according to reference ranges cited by the manufacturer and then were compared to analogously classified HPLC data, there were clearly more discrepancies between corresponding results from CDT TIA and HPLC (22%) than between ChronAlco and HPLC results (9%).

Conclusion: Including trisialo transferrin into the CDT fraction enlarges the analytical signal and therefore slightly improves assay precision but also results in a significant number of pathologic results in samples exhibiting physiologic levels of the classical CDT components asialo to disialo transferrin. As long as the diagnostic information of the trisialo transferrin concentration is largely unknown, we strongly recommend not to include this isotransferrin into the determination of CDT.