Capillary electrophoretic study on UDP-sugars in cells

Glucose is an important regulator of cell growth and metabolism. Uridine diphosphate sugars (UDP-sugars), as the intermediate products of metabolism, play pivotal roles as precursors in the synthesis of complex carbohydrates and glycolipids as well as lectose. It is very important to study their metabolism in cells in clinical biochemistry. A capillary electrophoretic method has been developed for the analysis of UDP-sugars and nucleotides, By using an uncoated capillary (70cm x 50 mu m) and 20 mmol/L borax buffer (pH 9), 4 important UDP-sugars can be analyzed in 15 min at 22 kV with satisfactory precision and sensitivity. The developed method has been applied to analyze UDP-sugars concentrations in lymphocytes, fibroblasts and mesangial cells, and the results show it not only is much better than HPLC method, but also can be used to measure the energy charge of cells.

A simple preparation of stationary phase of alkylamide reversed-phase liquid chromatograph for the separation of basic substances

A simple preparation process of alkylamide phase for reversed-phase HPLC (RP-HPLC) is described. The process includes aminopropyltrimethoxysilane firstly reacted with octanoyl chloride, then the intermediate was coupled onto porous silica. The resultant bonded silica has a reproducible ligand surface concentration and homogenous bonded ligand distribution on the porous silica. Characterization of prepared packing was carried out with elemental analysis, solid-state C-13 NMR and Fourier transform infrared (FT-IR). Chromatographic evaluations were carried out by using a mixture of organic compounds including acidic, basic and neutral analytes under methanol/water as binary mobile phase. The results showed that the stationary phase have excellent chromatographic properties and can be efficiently used for the separation of basic compounds.

Artificial neural network classification based on high-performance liquid chromatography of urinary and serum nucleosides for the clinical diagnosis of cancer

Nucleosides in human urine and serum have frequently been studied as a possible biomedical marker for cancer, acquired immune deficiency syndrome (AIDS) and the whole-body turnover of RNAs. Fifteen normal and modified nucleosides were determined in 69 urine and 42 serum samples using high-performance liquid chromatography (HPLC). Artificial neural networks have been used as a powerful pattern recognition tool to distinguish cancer patients from healthy persons. The recognition rate for the training set reached 100%. In the validating set, 95.8 and 92.9% of people were correctly classified into cancer patients and healthy persons when urine and serum were used as the sample for measuring the nucleosides. The results show that the artificial neural network technique is better than principal component analysis for the classification of healthy persons and cancer patients based on nucleoside data. (C) 2002 Elsevier Science B.V. All rights reserved.

Competing binding of metal ions with protein studied by microdialysis

A method has been established to study the competing binding of metal ions with protein by a combined technique of microdialysis with high performance liquid chromatography (HPLC). Ni2+, Cd2+, Zn2+, Cu2+ and human serum albumin (HSA) were chosen as model metal ions and protein. The experimental results show that Ni2+ and Cu2+ share a common primary binding site on HSA, and Zn2+ and Cd2+ share a different common primary binding site from them, but there is a common multi-metal binding site for all of those four metal ions. This method show advantages of fast sampling, easily to be operated and especially to be useful when ideal spectroscopic probes are not available for the study of interaction between protein and metal ions.

干燥方法和提取温度对板蓝根、大青叶有效成分的影响

目的研究干燥方法和提取温度对板蓝根、大青叶有效成分量的影响,为确定板蓝根、大青叶规范化生产的干燥技术参数提供理论依据。方法采用晒干、阴干和不同温度的烘干方法干燥板蓝根、大青叶,采用不同温度水浴提取有效成分,HPLC法测定靛蓝、靛玉红的量。结果60℃烘干板蓝根、大青叶有效成分损失最少,以60℃烘干为标准,高温(90℃以上)干燥使板蓝根有效成分损失40%~60%、大青叶有效成分损失30%—60%,阴干也降低了板蓝根、大青叶中的有效成分的量;采用索氏提取法、以氯仿为提取溶剂、水浴温度为80~85℃时对靛蓝、靛玉红的提取率最高,其次是90、75℃,95℃的提取率最低。结论50~80℃烘干和晒干是板蓝根、大青叶适宜的干燥方法,阴干和高温烘干的方法不可取。采用索氏提取方法、以氯仿为提取溶剂时,80~85℃水浴温度较为适宜。

由一株真菌产生的抑制血管细胞粘附分子-1基因表达的活性物质的研究

以血管细胞粘附分子-1（VCAM－1）基因为靶位点，使用含有荧光素酶报告基因的转染细胞株筛选模型M-4细胞从微生物的代谢产物中高通量筛选能够抑制VCAM－1基因表达的生物活性物质，以期找到能够治疗诸如类风湿性关节炎等免疫性疾病的新型药物。在筛选过程中使用有机溶媒萃取、ODS反相柱层析、HPLC制备等方法，从真菌FO－5897的发酵液中分离到了一个对测活用细胞株的荧光素酶报告基因的表达有中等强度抑制作用的化合物，其IC50为13．8μmol／L，经各种理化性质及1H－NMR分析确定该化合物与文献报道的具有降血脂和抗癌作用的化合物Ascofuranone的结构相同。

Effect of immersion in various media on the sorption, solubility, elution of unreacted monomers, and flexural properties of two model dental composite compositions

Immersion in various media has different effect on the properties of dental composites, such as sorption, solubility, elution of unreacted monomers, flexural strength, and flexural elastic modulus. In the present work, the effect of immersion in various media and the relationship between the variation of these properties and the components of dental composite were investigated.

高效液相色谱-质谱联用法分析龙胆中的环稀醚萜类成分

A rapid method was developed to analyze the extract of the Gentiana scabra Bge. by using high performance liquid chromatograghy-electrospray ionization multi-stage tandem mass spectrometry (HPLC-ESI-MSn). 5 compounds in Gentiana scabra Bge. are identified in the positive and negative mode. The research results demonstrate that the HPLC-ESI-MSn can quickly identified the components in Gentiana scabra Bge. . It also can provide the information of the relative molecular mass and chemical structure of the compounds in the extract of the Gentiana scabra Bge. .

北五味子不同炮制品中的木脂素类成分

研究北五味子炮制前后其中木脂素类成分的变化。采用电喷雾质谱(ESI-MS)以及高效液相色谱(HPLC)分别对经过不同方法炮制后的北五味子中木脂素类成分进行研究。北五味子经过不同方法炮制后,并没有新成分的生成,只是木脂素类成分含量有不同程度的变化。并对不同的炮制方法进行了比较。该方法准确、可靠,为北五味子不同炮制品的质量评价提供了一定的科学依据。

高效液相色谱法测定山茱萸与五味子配伍前后马钱苷、没食子酸及五味子醇甲的含量

目的考察山茱萸与五味子配伍前后两药主要组分的含量变化规律。方法利用高效液相色谱(HPLC)方法,比较了配伍前后单煎液、合煎液和单煎合并液中两药主要组分马钱苷、没食子酸和五味子醇甲的含量变化。结果在配伍比例较低(≤4:4)时,五味子促进了山茱萸中马钱苷的溶出。合煎液中的没食子酸、五味子醇甲组分的百分含量随着五味子配伍比例的增大呈线性减小,且均低于单煎液。单煎合并液中这3种组分的含量均高于同比例合煎液。结论山茱萸五味子配伍对两药主要组分溶出有较大影响,该影响主要在煎煮过程中发生。

五味子中木脂素类成分的高效液相色谱-电喷雾质谱研究

采用液相色谱-电喷雾质谱联用(HPLC-ESI-MSn)技术,对北五味子与南五味子中木脂素类成分进行了系统研究.通过HPLC-ESI-MS技术,获得了相应化合物的保留时间、紫外光谱和分子量等信息,利用电喷雾多级串联质谱技术(ESI-MSn),获得了相应化合物的结构信息.研究结果表明,北五味子与南五味子的主要木脂素成分除5个共有成分外其它成分差异较大,并且其共有成分含量差别较大.在此基础上,建立了简便、快速的北五味子与南五味子药材分析鉴定的新方法.

离子液体[omim][PF_6]的生物降解性研究

以[omim][PF6]为C、N、P营养源驯化活性污泥,考察驯化前后不同活性污泥接种微生物时离子液体的生物降解性,以及在支链上添加酯基对离子液体生物降解性的影响;同时,探讨经过驯化的活性污泥对1-甲基-3-辛基咪唑阳离子基团([omim]+)生物降解的途径.结果表明,通过在支链上添加酯基,可以改善离子液体的生物降解性;以普通的活性污泥为接种微生物的密闭瓶实验表明,[omim][PF6]的生物降解率<20%,属于难生物降解的物质,进入环境后可能产生较长时间的积累;以经过驯化的活性污泥为接种微生物时,可以提高[omim][PF6]的生物降解率到60%左右;在[omim]+的生物降解过程中,会产生1-甲基咪唑阳离子的积累;对[omim]+的生物降解产物的HPLC-MS/MS分析,初步推测[omim]+的生物降解途径.

Effects of ultrahigh pressure extraction conditions on yields and antioxidant activity of ginsenoside from ginseng

Ultrahigh pressure technique was employed to extract ginsenosides from roots of ginseng (Panax ginseng C.A. Meyer). The optimal conditions for ultrahigh pressure extraction (UPE) of total ginsenosides were quantified by UV-vis spectrophotometry with the ginsenoside Re as standard, the signal ginsenosides were quantified by HPLC and ELSD with ginsenosides Re, Rg(1), Rb-1, Rc and Rb-2 as standards. Orthogonal design was applied to evaluate the effects of four independent factors (extraction pressure, extraction temperature, extraction time and ethanol concentration) on the yield and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of ginsenoside, which are based on microwave extraction (ME), ultrasound extraction (UE), soxhlet extraction (SE) and heat reflux extraction (HRE) method. The results showed that UPE method can produce ginsenoside with the highest yield and the best radical scavenging activity compared to other used ones. Scanning electron microscopic (SEM) images of the plant cells after ultrahigh pressure treatment was obtained to provide visual evidence of the disruption effect.

Studies on principal components and antioxidant activity of different Radix Astragali samples using high-performance liquid chromatography/electrospray ionization multiple-stage tandem mass spectrometry

The principal components, isoflavonoids and astragalosides, in the extract of Radix Astragali were detected by a high-performance liquid chromatography Couple to electrospray ionization ion trap multiple-stage tandem mass spectrometry (HPLC-ESI-IT-MSn) method. By comparing the retention time (t(R)) of HPLC, the ESI-MSn data and the structures of analyzed Compounds with the data of reference compounds and in the literature, 17 isoflavonoids and 12 astragalosides have been identified or tentatively deduced. By Virtue of the extracted ion chromatogram (EIC) mode, simultaneous determination of isoflavonoids and astragalosides could be achieved when the different components formed overlapped peaks. And this method has been utilized to analyze the constituents in extracts of Radix Astragali from Helong City and of different growth years. Then the antioxidant activity of different samples has been Successfully investigated by HPLC-ESI-MS method in multiple selected ion monitoring(MIM) mode, applying the spin trapping technology, and the Ferric Reducing Antioxidant Power (FRAP) assay was applied to support the result.