高效液相色谱测定血清中的非胆因醇甾醇

本文介绍一种用高效液相色谱同时测定血清中２４－脱氢胆固醇、７－烯胆甾烷醇、菜油甾醇、胆甾烷醇和β－谷甾醇的方法。血清加内标（６－氯豆甾醇）后用氢氧化钾醇溶液皂化,用正已烷提取其中的各种甾醇,将提出的甾醇衍生为苯氨基甲酸酯,用ＨＰＬＣ分离测定。本法样品处理简单,色谱分析时间短,批内和批间变异系数分别为２．２～３．８％和３．３～６．７％。本文也首报告我国成年人血清非胆固醇甾醇水平,５种甾醇血清深度的总     

在氢氧化铝凝胶灭活寨卡病毒疫苗中甲醛残留量的测定方法

<正>建立了一种简便测定氢氧化铝凝胶配制的灭活寨卡病毒疫苗中甲醛残留量的方法,以用于药品质量评价。甲醛与2,4-二硝基苯肼(DNPH)反应,衍生产物用高效液相色谱检测,检测波长为360 nm。衍生化反应可在高效液相色谱中2 mL样品管进行样品直接分析。该方法已根据国际药品注册协调会议Q2指南得到充分验证。氢氧化铝凝胶质量浓度达     

反相高效液相色谱法测定厌氧菌有机酸代谢产物

建立反相高效液相色谱测定厌氧菌代谢发酵有机酸产物(乙酸、乳酸)的方法并用于测定乳酸菌代谢发酵产物中的含量。反相高效液相方法是一种简单、准确、灵敏的方法,可用于同时定量测定厌氧菌的有机酸代谢产物。     

薄层色谱和高效液相色谱联用测定暗纹东方鲀肌肉中肌肽和谷胱甘肽的含量

通过薄层色谱(TLC)与高效液相色谱(HPLC)联用技术鉴定了暗纹东方鲀(Takifugu obscurus)肌肉中存在肌肽和谷胱甘肽,同时利用高效液相色谱法测定了肌肽和谷胱甘肽(GSH)的含量。薄层层析采用的展开剂为正丁醇:乙酸:水(4∶2∶1),层析板为硅胶板。高效液相色谱利用Kromasil C18反相柱分析,流动相为10%的纯乙腈和90%含有0.05%三氟乙酸的超纯水。结果表明:通过薄层色谱和高效液相色谱鉴定了暗纹东方鲀肌肉中肌肽和谷胱甘肽,其中暗纹东方鲀肌肉中肌肽含量约213μg/g(鲜重),还原性谷胱甘肽含量约211μg/g(鲜重)。本法样品无需衍生,操作简便,适合于暗纹东方鲀肌肉中肌肽和谷胱甘肽的测定。本文为生物体内肌肽和谷胱甘肽的研究提供借鉴意义。     

氧化型胆固醇引起的血管平滑肌细胞氧化应激损伤研究

以胆固醇为对照,研究动脉粥样硬化症中常见的两种氧化型胆固醇（３β,５α,６β－三羟胆固烷、２５－羟胆固醇）对血管平滑肌细胞损伤及损伤机制。结果表明,于损伤早期,细胞的谷胱甘肽过氧化物酶活性增高,还原型谷胱甘肽含量减少。损伤后期谷胱甘肽过氧化物酶活性下降,细胞谷胱甘肽耗竭,细胞总巯基含量下降,细胞脂质过氧化产物含量和细胞羰基含量明显增高,表明细胞出现严重的氧化性损伤。而纯胆固醇,在与这两种氧化型胆固醇相同的作用时间,作用条件及剂量大于这两种氧化型胆固醇两倍以上的情况下,未曾引起细胞抗氧化酶、谷胱甘肽、蛋白质及脂质的任何明显改变。外给金属硫蛋白可减轻细胞损伤,外给Ｌ－ｂｕｔｈｉｏｎｅｉｎ－［Ｓ,Ｒ］－ｓｕｌｆｏｘｉｍｉｎｅ使细胞损伤加重,说明损伤与巯基含量有关。结果提示氧化型胆固醇引起的细胞损伤可能是通过氧应激产生。     

气相色谱法测定发酵液中胆固醇的含量

气相色谱法测定了发酵液中胆固醇的含量。采用Rtx-1（100%二甲基聚硅氧烷）毛细管色谱柱、FID检测器进行分析测定。当胆固醇浓度在0～200μg/mL范围内与色谱峰面积呈良好线性关系（r=0.9981）。方法的平均回收率为99.38%,相对标准偏差为0.75%（n=8）,最低检出限可达到0.816μg/mL。气相色谱法作为发酵液中胆固醇含量的快速测定方法,具有试剂用量少、操作简单、结果准确等特点。     

罗汉果果肉中糖类物质组成与含量分析

罗汉果果实中富含糖分,糖类物质的组成及其含量对果实的内在品质有重要影响,然而多年来对其品质的研究多集中在罗汉果苷上,果实中可溶性糖种类与含量迄今尚未见有系统地报道。该研究以干燥的罗汉果果实为材料,采用PMP柱前衍生化一高效液相色谱紫外检测法、高效液相色谱示差折光检测法分别检测果肉中可溶性糖的种类与含量,并进行方法学考察。结果表明:PMP柱前衍生化一高效液相色谱紫外检测法只能检出罗汉果果实中存在的2种还原性醛糖——葡萄糖、甘露糖;而高效液相色谱示差折光检测法则可一次性检出葡萄糖、果糖、蔗糖、棉籽糖、多糖5种糖分。与柱前衍生化法相比,高效液相色谱示差折光检测法更适合用来全面分析罗汉果果实中糖分的种类和含量。不同罗汉果品种果实中糖的组分一致,但含量有显著差别。另外,样品的干燥方式会影响果实中的总糖及各组分的相对含量。冻干果肉中蔗糖和葡萄糖相对含量最高,烘干则导致蔗糖和葡萄糖下降,果糖与多糖相对含量增加。     

氧化型胆固醇与动脉粥样硬化的关系

氧化型胆固醇是胆固醇氧化衍生物,多达上百种。氧化型胆固醇存在于胆固醇膳食,高胆固醇血症的血浆和动脉组织、人动脉粥样硬化斑块和斑块内的泡沫细胞,以及氧化型低密度脂蛋白中。大量实验表明氧化型胆固醇对与动脉粥样硬化形成有关的细胞（如血管内皮细胞,平滑肌细胞以及单核／巨噬细胞等）具有毒性作用,提示,氧化型胆固醇在动脉粥样硬化的发生和演变中具有不可忽视的作用。     

应用柱前衍生化高效液相色谱法开辟了一种简单、快速的DNJ产生菌的筛选途径

【目的】应用柱前衍生化高效液相色谱法筛选产1-脱氧野尻霉素(DNJ)菌株,并对其进行系统鉴定。【方法】利用芴甲氧酰氯(FMOC-Cl)柱前衍生化高效液相色谱法筛选DNJ产生菌;通过形态特征、培养特征、生理生化特征以及16S rRNA序列相似性分析等多项分类方法对DNJ产生菌进行鉴定;在10 L发酵罐水平进行发酵研究,利用FMOC-Cl柱前衍生化高效液相色谱法测定DNJ含量。【结果】从80株具有α-糖苷酶抑制剂活性的土壤放线菌中筛选得到一株DNJ产生菌,菌株编号为PW409,初步确定为戈壁三素链霉菌(Streptomyces gobitrici);发酵研究表明,DNJ为链霉菌PW409的次级代谢产物,发酵液中DNJ浓度为12.1 mg/L。【结论】首次将FMOC-Cl柱前衍生化高效液相色谱法应用于DNJ产生菌的筛选,并首次报道从戈壁三素链霉菌发酵液中鉴定到DNJ。     

高效液相色谱-柱后光化学衍生法测定变性淀粉中黄曲霉毒素含量的研究

本文采用高效液相色谱-柱后衍生法对变性淀粉中的黄曲霉毒素G2、G1、B2和B1含量进行测定.样品采用乙腈-水(84:16,v/v)提取,经免疫亲和柱净化,C18色谱柱分离,以乙腈-甲醇-水(10:30:60,v/v)为流动相进行洗脱,用HPLC光化学衍生-荧光检测器检测样品含量.结果表明,4种黄曲霉毒素的标准曲线线性均...     

细胞内胆固醇水平调节研究进展

细胞内胆固醇水平动态平衡是细胞发挥生理功能的重要保障.破坏细胞内胆固醇水平动态平衡不仅增加心血管系统疾病患病风险,而且与许多代谢性疾病相关.细胞内胆固醇水平主要受胆固醇生物合成、摄取、流出和酯化的调节.3-羟基-3-甲基-戊二酰基辅酶A还原酶、角鲨烯单加氧酶和固醇调节元件结合蛋白2是胆固醇合成关键因子.尼曼-匹克C1型...     

以芳香胺玻璃为载体的固定化的胆固醇脂酶和胆固醇氧化酶

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A physiologically based in silico kinetic model predicting plasma cholesterol concentrations in humans

Increased plasma cholesterol concentration is associated with increased risk of cardiovascular disease. This study describes the development, validation, and analysis of a physiologically based kinetic (PBK) model for the prediction of plasma cholesterol concentrations in humans. This model was directly adapted from a PBK model for mice by incorporation of the reaction catalyzed by cholesterol ester transfer protein and contained 21 biochemical reactions and eight different cholesterol pools. The model was calibrated using published data for humans and validated by comparing model predictions on plasma cholesterol levels of subjects with 10 different genetic mutations (including familial hypercholesterolemia and Smith-Lemli-Opitz syndrome) with experimental data. Average model predictions on total cholesterol were accurate within 36% of the experimental data, which was within the experimental margin. Sensitivity analysis of the model indicated that the HDL cholesterol (HDL-C) concentration was mainly dependent on hepatic transport of cholesterol to HDL, cholesterol ester transfer from HDL to non-HDL, and hepatic uptake of cholesterol from non-HDL-C. Thus, the presented PBK model is a valid tool to predict the effect of genetic mutations on cholesterol concentrations, opening the way for future studies on the effect of different drugs on cholesterol levels in various subpopulations in silico.     

A simple and sensitive enzymatic method for cholesterol quantification in macrophages and foam cells

A precise and sensitive method for measuring cellular free and esterified cholesterol is required in order to perform studies of macrophage cholesterol loading, metabolism, storage, and efflux. Until now, the use of an enzymatic cholesterol assay, commonly used for aqueous phase plasma cholesterol assays, has not been optimized for use with solid phase samples such as cells, due to inefficient solubilization of total cholesterol in enzyme compatible solvents. We present an efficient solubilization protocol compatible with an enzymatic cholesterol assay that does not require chemical saponification or chromatographic separation. Another issue with enzyme compatible solvents is the presence of endogenous peroxides that interfere with the enzymatic cholesterol assay. We overcame this obstacle by pretreatment of the reaction solution with the enzyme catalase, which consumed endogenous peroxides resulting in reduced background and increased sensitivity in our method. Finally, we demonstrated that this method for cholesterol quantification in macrophages yields results that are comparable to those measured by stable isotope dilution gas chromatography with mass spectrometry detection. In conclusion, we describe a sensitive, simple, and high-throughput enzymatic method to quantify cholesterol in complex matrices such as cells.     

Ezetimibe inhibits the incorporation of dietary oxidized cholesterol into lipoproteins

Oxidized cholesterol is present in significant quantities in the typical Western diet. When ingested, oxidized cholesterol is absorbed by the small intestine and incorporated into both chylomicrons and LDL, resulting in LDL that is more susceptible to further oxidation. Feeding studies in animal models and epidemiological studies in humans have suggested that oxidized cholesterol in the diet increases the development of atherosclerosis. In this study, we determined the effect of ezetimibe, a drug that inhibits small intestinal absorption of cholesterol, on the levels of oxidized cholesterol in the serum after a test meal containing oxidized cholesterol. We demonstrate that ezetimibe, 10 mg per day for 1 month, markedly reduced the levels (50% decrease) of oxidized cholesterol in the serum after feeding a test meal containing either alpha-epoxy cholesterol or 7-keto cholesterol, two of the predominant oxidized cholesterols found in the diet. Moreover, the decrease in oxidized cholesterol in the serum was attributable to a decrease in the incorporation of dietary oxidized cholesterol into both chylomicrons and LDL. Because there was no decrease in postprandial triglyceride levels, we conclude that this decrease in oxidized cholesterol levels in the serum is attributable to decreased absorption and not to enhanced clearance. Whether this decrease in oxidized cholesterol absorption prevents or delays the development of atherosclerosis remains to be determined.     

Prevalence of coronary heart disease risk factors in a Cambridge, UK study

This paper examines the distribution and prevalence of risk factors for coronary heart disease in a sample of 165 men and 202 women over 40 years of age who had earlier participated in a coronary prevention trial from a general practice in Cambridge, UK. No significant differences were observed in total cholesterol levels between men and women, and a quarter of the sample had concentrations above 6.5 mmol/l which is 250 mg/dl. There were significant sex differences in a number of risk factors with males having significantly higher prevalence of low high density lipoprotein, systolic and diastolic blood pressures, obesity, and smoking than women. About 8% of men and women were obese (as defined by a body mass index > 30), while 47% of men and 35% of women were mildly overweight (body mass index > 25). Two or more risk factors for coronary heart disease (high total cholesterol and/or hypertension and/or obesity) were present in 4% and 9% of older men and women respectively. Furthermore, about half the subjects had more than one risk factor for coronary heart disease.     

An apolipoprotein A-I mimetic dose-dependently increases the formation of prebeta1 HDL in human plasma

Prebeta1 HDL is the initial plasma acceptor of cell-derived cholesterol in reverse cholesterol transport. Recently, small amphipathic peptides composed of D-amino acids have been shown to mimic apolipoprotein A-I (apoA-I) as a precursor for HDL formation. ApoA-I mimetic peptides have been proposed to stimulate the formation of prebeta1 HDL and increase reverse cholesterol transport in apoE-null mice. The existence of a monoclonal antibody (MAb 55201) and a corresponding ELISA method that is selective for the detection of the prebeta(1) subclass of HDL provides a means of establishing a correlation between apoA-I mimetic dose and prebeta1 HDL formation in human plasma. Using this prebeta1 HDL ELISA, we demonstrate marked apoA-I mimetic dose-dependent prebeta1 HDL formation in human plasma. These results correlated with increases in band density of the plasma prebeta1 HDL, when observed by Western blotting, as a function of increased apoA-I mimetic concentration. Increased prebeta1 HDL formation was observed after as little as 1 min and was maximal within 1 h. Together, these data suggest that a high-throughput prebeta1 HDL ELISA provides a way to quantitatively measure a key component of the reverse cholesterol transport pathway in human plasma, thus providing a possible method for the identification of apoA-I mimetic molecules.