Development of a Stationary Phase of Vascular Smooth Muscle Cell Membrane Chromatography and Its Chromatographic Affinity Characteristics

A novel stationary phase of vascular smooth muscle cell membrane chromatography (VSM-CMC) was developed by immobilizing the vascular smooth muscle cell membrane onto the surface of silica and was presented for bioaffinity chromatography. The protein level and Na⁺, K⁺-ATP enzymatic activity of the vascular smooth muscle cell membrane stationary phase (VSM-CMSP) were detected. The surface characteristics of the VSM-CMSP were tested using scanning electron microscopy and surface energy spectrometry. The retention characteristics of four dihydropyridines (amlodipine besylate, nicardipine hydrochloride, nitrendipine and nifedipine) were investigated using a VSM-CMSP column (10 mm × 2 mm, I.D.) packed with VSM-CMSP. The logarithm of the capacity factor (logk??) was taken as a measure of the affinities of the calcium antagonists toward the vascular smooth muscle cell membrane and receptors. The surface characteristics of the VSM-CMSP were very different from that of the normal and reversed stationary phase, and the VSM-CMSP was found to have cell membrane activity and chromatographic separation. Moreover, there was a significant correlation between the affinity in the VSM-CMC system and the effect in vitro with respect to the pharmacological effect. It is concluded that the VSM-CMC system can serve as a type of bioaffinity chromatography for studying the interaction between drug molecules and target sites (e.g., receptors) in cell membranes, and for screening active compounds from complex agents.     

色谱法中的谱带和色谱峰

对色谱法中的谱带作了具体的定义。详细论述了谱带与色谱峰之间的关系,指出分析谱带是研究色谱现象的基础。色谱法中的色谱峰并不局限于色谱图中的色谱峰,只要是组分的分析谱带,都可以形成一个色谱峰与之相对应。     

磷脂膜色谱及其在药物跨膜转运评价中的应用

磷脂膜色谱是固态基质上的有序磷脂分子单层体系采用色谱学方法仿真药物与细胞膜相互作用过程,可用来评价药物的细胞膜渗透性和活性。硅胶表面上的磷脂单分子层模拟了单层细胞膜,因此药物的磷脂膜色谱保留行为可用于预测药物与细胞膜的相互作用。目前考察药物跨膜转运的模型主要有正辛醇/水系统、脂质体/水系统、反相色谱（ODS）以及磷脂膜色谱。与前述3种系统比较,磷脂膜色谱除了具有高效、简便等特点外,同时能模拟药物与生物膜之间疏水作用力以外的其他作用力,因此对磷脂膜色谱的研究也越来越深入。由于药物细胞膜渗透性对其有效性和安全性起着关键作用,因此磷脂膜色谱在新药研发早期阶段的介入可以有效地降低后期候选药物的淘汰率,提高新药的研发效率。该文就磷脂膜色谱的研究及在药物跨膜转运评价中的应用进行了综述。     

Preparation and Application of Modified VEGFR-2 Cell Membrane Chromatographic Separation System

The vascular endothelial growth factor receptor-2 (VEGFR-2) in some tumor cells is a significant target for drug discovery. In this work, a modified model of VEGFR-2 cell membrane stationary phase (CMSP) was prepared by immobilizing U251 cell membrane onto the surface of chitosan-silica (CTS-SiO₂) hybrid carrier. The surface and chromatographic characteristics of VEGFR-2 CMSP were studied. We have developed modified VEGFR-2 cell membrane chromatography for screening drugs and sunitinib malate was used as a positive control. The interaction between the new compounds and membrane receptor was determined by the capacity factors (kʹ). The in vitro cytotoxicity of 10 new compounds on U251 cell viability was determined by MTT test separately to verify the potential pharmacological activity. The modified VEGFR-2 cell membrane chromatographic system demonstrated fast and effective characteristics for screening leading compounds.

     

Determination of Pharmaceuticals by Dynamic Cell Membrane Chromatography Coupled with High-Performance Liquid Chromatography

As a biological affinity chromatographic method, cell membrane chromatography (CMC) using a silica stationary phase covered with specific cell membrane has been used in screening active components. The innovation of this work is that the bioactive cell membrane and the chromatographic packing are mixed and absorbed for the first time to form the pre-column. The pre-column was placed in front of a C₁₈ column to create dynamic CMC online high-performance liquid chromatography (HPLC) system. The retention behavior and dynamic changes of pharmaceuticals were studied for this system. The results indicate that the retention time of the drug was increased and the symmetry factor reached the analytical level after the addition of the dynamic cell membrane pre-column. Therefore, the dynamic CMC coupled with HPLC system may be a potentially rapid and efficient drug analysis approach for the interaction of drug molecule and receptor on red blood cell membranes.     

疏水作用色谱介质的合成及色谱特性研究

利用国产大孔硅胶作基质合成了疏水填料。按照高效疏水作用色谱法,采用梯度洗脱方式分离了6种标准蛋白及唾液中α-淀粉酶和基因工程生产的γ-干扰素。柱子不可逆吸附小、被试验的α-淀粉酶和溶菌酶活性几乎定量被回收。应用合成的色谱填料研究了洗脱剂中盐浓度和温度对蛋白质保留行为的影响,论证了合成填料的色谱属性。     

Novel Cell Membrane Capillary Chromatography for Screening Active Compounds from Natural Products

Cell membrane chromatography (CMC) is a useful method for the simultaneous isolation and identification of active compounds from natural products. However, it suffers from high cell membrane consumption and is time-consuming to operate. In this study, CMC was performed for the first time with a silica capillary, termed cell membrane capillary chromatography (CMCC). Pancreatic islet cell membranes from a mouse were immobilized onto the capillary inner wall functionalized with aldehyde groups. Scanning electron microscopy observation of the prepared column showed that the cell membrane was evenly coated onto the capillary inner wall. Three model analytes with the pharmacological property of hypoglycemic activity including glibenclamide, glipizide and berberine were tested. They were all retained by the prepared column. Furthermore, the retention factors of the analytes in CMCC correlated well with their pharmacological action. The analytical procedure including washing (to obtain a flat baseline), injection and separation was accomplished within 10 min. The CMCC column was also used for screening active compounds from a natural plant (Coptis chinensis). The hypoglycemia activity of active components such as berberine was verified using the method. The results indicated that CMCC is a viable alternative method for screening active compounds from natural products.

     

Novel Cell Membrane Capillary Chromatography for Screening Active Compounds from Natural Products

Cell membrane chromatography (CMC) is a useful method for the simultaneous isolation and identification of active compounds from natural products. However, it suffers from high cell membrane consumption and is time-consuming to operate. In this study, CMC was performed for the first time with a silica capillary, termed cell membrane capillary chromatography (CMCC). Pancreatic islet cell membranes from a mouse were immobilized onto the capillary inner wall functionalized with aldehyde groups. Scanning electron microscopy observation of the prepared column showed that the cell membrane was evenly coated onto the capillary inner wall. Three model analytes with the pharmacological property of hypoglycemic activity including glibenclamide, glipizide and berberine were tested. They were all retained by the prepared column. Furthermore, the retention factors of the analytes in CMCC correlated well with their pharmacological action. The analytical procedure including washing (to obtain a flat baseline), injection and separation was accomplished within 10 min. The CMCC column was also used for screening active compounds from a natural plant (Coptis chinensis). The hypoglycemia activity of active components such as berberine was verified using the method. The results indicated that CMCC is a viable alternative method for screening active compounds from natural products.     

缬氨霉素作为毛细管气相色谱新型固定相的性能研究

本文研究了缬氨霉素的气相色谱特性, 考察了它们对一些难分离物质对、位置异构体以及一些手性化合物的分离效果. 除文献[3]外, 目前尚未见到有关将环状肽作为色谱固定相的报道.     

十八碳键合钛胶固定相的制备及其色谱性能

 以聚合诱导胶体凝聚法 (PICA)合成的窄粒径分布的TiO2 多孔微球 (表面积 :3 6 7m2 /g ,孔容 :0 3 0mL/g ,平均孔径 :3 2 2nm ,平均粒径 :3 5 μm)为基质 ,与十八碳三甲氧基硅烷的甲苯溶液共同回流 8h ,制得十八碳键合钛胶固定相 (ODT)。该固定相的含碳量为 2 87% (即 0 66μmol/m2 ) ,疏水选择性为 0 4 63 8。将其用于分离中性和碱性化合物时 ,显示出比较好的色谱性能。     

Effect of Water Vapor on Chromatographic Characteristics of the Cyclodextrin-Containing Stationary Liquid Phase in Capillary Gas Chromatography

The effects of the presence of water vapor in the carrier gas and the temperature on the retention of achiral and chiral compounds, enantioselectivity, and performance of an open-tubular column with a cyclodextrin-containing phase were studied. The use of a carrier gas containing water vapor in the determination of optically active isomers, such as camphor, slightly increases the retention factor. A substantial improvement of performance characteristics of the column was found: for hydroxy compounds, the column performance increased by two to three times and the peak symmetry improved by more than twice.     

壳聚糖膜的处理方法与其渗透汽化性能间的关系

对壳聚糖均质膜折脱酸处理、干燥方法与所得膜的渗透汽化性能间的关系进行了研究。结果表明，处理方法的不同直接影响到膜的透过、分离性能。用含３ｗｔ．％ＮａＯＨ的醇水溶液（乙醇／水＝５０／５０（ｗｔ．／ｗｔ．））进行脱酸处理的膜，其α水／乙醇值，在料液温度为５５－７５℃的范围内几乎不变。     

Cell Membrane Chromatography Correlated with Functional Assay for Ligand–β-Adrenergic Receptor Affinities

This study was performed to investigate whether the retention factor (k) from cell membrane chromatography (CMC) can be used to assess the affinity of ligands to β-adrenergic receptor (β-AR) and the correlationship between the factor and pharmacoligical effects. The cell membrane of guinea pig myocardium membrane was immobilized on the surface of the silica carrier as the cell membrane stationary phase (CMSP) for the rapid on-line chromatographic evaluation of ligand binding affinity to β-AR. The affinity was also evaluated by functional assay using the same tissues. Correlation analysis was used to assess the correlationship of these two methods. The retention factors in guinea pig myocardium CMSP were: (−)-propranolol (33.9) > (+)-propranolol (27.0) > metopranolol (23.2) > esmolol (17.7) > practolol (13.2) > sotalol (9.56). Compared to the affinity rank orders obtained from functional assay in the same myocardium, there was a positive correlation (r ² = 0.9729, n = 18, p < 0.0001) between both data sets. These results showed that CMC can be used to evaluate drug–receptor affinities of drug candidates as the functional assays.

     

Cell Membrane Chromatography Correlated with Functional Assay for Ligand–β-Adrenergic Receptor Affinities

This study was performed to investigate whether the retention factor (k) from cell membrane chromatography (CMC) can be used to assess the affinity of ligands to β-adrenergic receptor (β-AR) and the correlationship between the factor and pharmacoligical effects. The cell membrane of guinea pig myocardium membrane was immobilized on the surface of the silica carrier as the cell membrane stationary phase (CMSP) for the rapid on-line chromatographic evaluation of ligand binding affinity to β-AR. The affinity was also evaluated by functional assay using the same tissues. Correlation analysis was used to assess the correlationship of these two methods. The retention factors in guinea pig myocardium CMSP were: (?)-propranolol (33.9) > (+)-propranolol (27.0) > metopranolol (23.2) > esmolol (17.7) > practolol (13.2) > sotalol (9.56). Compared to the affinity rank orders obtained from functional assay in the same myocardium, there was a positive correlation (r ² = 0.9729, n = 18, p < 0.0001) between both data sets. These results showed that CMC can be used to evaluate drug–receptor affinities of drug candidates as the functional assays.     

质子交换膜燃料电池模型研究进展

综述了质子交换膜燃料电池 (PEMFC)数学模型的研究进展 ,分析PEMFC中膜、催化层、扩散层和流场区域的传递现象和水、热管理的重要性 ,讨论了模型的维数、复杂性和求解方法 .提出了带有时间维数的PEMFC模型研究的实际应用意义     

细胞膜离子通道的一个非线性动力学模型

提出一个关于细胞膜离子通道的非线性动力学模型，此模型克服了Liebovitch模型的一些严重缺陷，也更符合通道中离子运动实际．模型导出的Ⅰ-Ⅴ曲线与实验结果符合得很好．