乳酸胆固醇酯的合成与表征

乳酸酯广泛应用于化妆品、药剂、乳化剂等方面。胆固醇（胆甾醇）酯是一种具有液晶相的化合物，其在一定条件下，会随温度、磁场、电场、机械应力、气体浓度变化，而发生色彩的变化，可用于制作液晶温度计、气敏元件、电子元件、变色物质等，还可用于无损伤探伤、微波测量、治病诊断、定向反应等化学、化工、冶金、医学等领域。     

长寿金丹——锰

锰是人体不可缺少的微量元素。锰是丙酮酸脱羧酶的组成部分，也是许多酶系统的重要活化剂，它能促进、增强人体内许多重要的代谢反应。人体如缺锰，会导致生长发育障碍、身体矮小、瘦弱、智力下降、反应迟钝、贫血、面色苍白、无力以及共济失调、平衡障碍等中枢神经系统症状。由于锰参与人体内胆固醇的合成，而胆固醇是性激素的前体，所以缺锰可引起性激素缺乏，导致不育症。     

半微分吸附伏安法测定胆固醇

本文首次报道了胆固醇的直接电化学测定方法─半微分吸附伏安法, 在K2HPO4溶液中, 胆固醇的开路情况下于悬汞电极上产生了吸附, 吸附后的胆固醇在电极上还原, 还原峰电位分别为-1.0和-1.40V(vs. SCE), 其中第一还原峰的峰电流与浓度在10^-^7和10^-^6mol·dm^-^3范围内具有线性关系, 相关系数分别为0.999和0.997。作者对胆固醇吸附的条件, 有关化合物的影响进行了研究, 提出了测定方法, 检测限达到2.3×10^-^8mol·dm^-^3, 是目前报道的最灵敏的分析方法之一。使用该方法对血清中胆固醇含量进行了实测, 结果与临床使用的酶法相符合。     

几种β-环糊精包合物的热分解反应动力学的比较

β 环糊精(简称β ＣＤ)具有亲水的外围及疏水的内腔,在溶液中可与许多有机物形成包合物[1,2]。有关物质的量比为1∶1的包合物的热分解研究已有报道[3-5],但研究不同物质的量比包合物的热分解反应却未见报道。本文用非等温热重法比较了β ＣＤ与胆固醇、癸二酸和香兰素的包合物热分解反应动力学,得到其热分解表观活化能。1　实验部分1 1　仪器与试剂岛津ＤＴ-40热分析系统;β 环糊精(化学纯,上海化学试剂公司)经水重结晶2次;癸二酸(汕头市光华化学厂)与香兰素、胆固醇(上海化学试剂站分装厂)均为分析纯试剂。1 2　包合物的制备及ＴＧ分…     

生物金属与胆固醇相互作用的经验势函数计算

流行病学调查和医学实验均证实，以胆固醇在动脉血管壁沉着、形成病灶及纤维增生使管壁变硬为特征的动脉粥样硬化（AS），与血中某些金属元素的水平密切相关＊．一些临床医学观测报道了冠心病患者血中金属元素铜、锌、铬、钢等的水平与胆固醇含量变化的关系［2－6］，以期通过改善人体内微量元素的失调来抑制AS的发生和发展．AS患者血中生物金属铜、锌、铬、锅水平与胆固醇含量有关，可能意味着两者存在某种相互作用制约关系．本文通过金属一胆固醇间、胆固醇分子间、受金属离子影响的胆固醇分子间的各种模型构造，选用恰当的经验势函数…     

葡聚糖为载体的双亲型LDL吸附剂吸附动力学研究

合成了以葡聚为载体，同时具有亲水性磺酸基和疏水性胆固醇两类配基的新型低密度脂蛋白（LDL）吸附剂。通过对LDL纯溶液中吸附等温线的测试，比较了以Dextran G-75为载体的双亲型LDL吸附剂与单一亲水型磺酸基配基，单一疏水型胆固醇基吸附剂吸附量和亲和吸附系数的关系。对双亲型LDL吸附剂的吸附动力学进行了初步研究，在LDL溶液中，亲水型磺酸基，疏水型胆固醇配基，双亲型LDL吸附剂对LDL的吸附曲线基本上符合Langmuir吸附方程，另外通过高离子强度NaCl洗脱实验，测定了双亲型LDL吸附剂上具有的磺酸基与胆固醇两类基在对低密脂蛋白吸附过程中所起的配合效果，为下一步作用力机制研究提供了参考依据。     

磷脂水解与胆固醇型胆结石时的可能生成机理

用胆酸盐-磷脂-胆固醇-水体系模拟胆汗的化学行为。在体系中发现，磷脂可 以发生降解形成脂肪酸。而在胆汗中，磷脂在增溶固醇的过程中起到了十分重要的 作用。依此，我们提出磷脂的水解可能与胆固醇型胆结石的生成有密切关系。     

水溶液中Cr^3＋在胆固醇上的吸附

水溶液中Ｃｒ３＋在胆固醇上的吸附曹槐宋仲容ａ沈智王光灿朱光辉（云南大学化学系现代生物中心实验中心昆明６５００９１）（ａ重庆师范专科学校）医学实验报道［１，２］，铬元素能抑制体内胆固醇和脂肪酸的合成。人体缺乏铬时，葡萄糖耐量受损，血内脂肪及类脂（特别是...     

流化床煤气化炉内脱硫的研究 Ⅱ．脱硫剂焙烧反应动力学与脱硫反应动力学初步研究

钙质脱硫剂的焙烧反应是炉内脱硫的关键过程，本文研究了影响石灰石和白云石焙烧速率的因素。操作温度７５０℃以上时，焙烧速率很快。ＣＯ_２分压显著地影响焙烧过程，Ｐ_（ＣＯ）２高于平衡分压时，石灰几乎不分解。在本实验的粒度范围内，脱硫剂粒度对焙烧速率影响不大。采用未反应核收缩模型模拟焙烧过程的结果和实验结果基本一致。脱硫反应速率对气相Ｈ_２Ｓ浓度呈一级反应，操作温度特别在６００～７００℃的低温时显著地影响反应速率。     

食品中胆固醇色谱／质谱／质谱的测定

确立了用色谱／质谱／质谱测定食品中胆固醇的一种新方法，试样经乙酸乙酯提取后，ＧＣ／ＭＳ／ＭＳ测定分析，以胆固醇分子离子为母离了，以其子离子为定量分析的碎片离子。线性好，回收率高，方法可靠。     

流动注射化学发光法测定人体血清中的胆固醇

流行病学和临床证明,血清中胆固醇含量的高低和人体的心血管疾病等有着十分密切的关系[1],因而血清胆固醇测定可作为肝脏功能、胆汁功能、肠吸收、冠状动脉疾病、甲状腺功能和肾上腺疾病的诊断指征。血清中胆固醇含量的测定方法有分光光度法、酶法、化学发光法、色谱法、气质联     

Microcalorimetric Determination of Serum Triglycerides and Cholesterol

Abstract

Reaction heats measured in a microcalorimeter between varying amounts of human serum and 700 IU of lipase (EC 3.1.1.3) and those between serum and 8 U of cholesterol oxidase (EC 1.1.3.6) were significantly linear with the contents of triglycerides (r=1.00) and cholesterol (r=0.99), respectively. However, when sera from 13 human volunteers were subject to comparative study between the micro-calorimetric and spectrophotometric methods, the correlation became less appreciable (r=0.70 and r=0.71) presumably due to the individual variations in free glycerol and cholesterol ester-constituents that were deliberately omitted in the microcalorimetric method but were routinely included in the standard (multi-enzymatic) spectro-photometric clinical method. The contribution of interfering substances, if any, is not totally ruled out.     

Thermal analysis and microscopical characterization of cholesterol in gallstones

Summary Cholesterol constitutes the major component of most gallstones. It was identified and determined in gallstones by thermal analysis technique (DSC and TG-DTA), mainly by the use of the melting temperature (T_onset=145°C and T_max=149°C) and by DTG peak decomposition (T_max=364°C). Cholesterol anhydrous (ChA), which showed endothermic polymorphic peak, T_max=40°C, without mass loss, was differentiated from cholesterol monohydrate (ChH), which showed a broad endothermic peak, T_max=59°C, attributed to loss of water of crystallization (theoretical 4.45%). Morphological studies of gallstones were performed by optical microscopy and scanning electron microscopy (SEM). The stones consisted of a pigmented core with a variably-sized irregular central cavity, surrounded by a radially arranged deposits of plate-like ChH. The outer part of the stones showed ChA crystal arborescences. X-ray microanalysis gave a typical spectrum rich in C and O, and in some instances the presence of P, which was attributed to the presence of phospholipids. CaCO₃ was easily characterized by TG with the use of DTG decomposition peak at 674°C.     

Polypyrrole/multiwalled carbon nanotubes‐based biosensor for cholesterol estimation

The nanocomposite electrode comprising of polypyrrole (PPY) and carboxy functionalized multiwalled carbon nanotubes (MWCNT) has been electrochemically fabricated onto indium–tin–oxide (ITO) electrode using p‐toluene sulfonic acid (PTS). Cholesterol oxidase (ChOx) and cholesterol esterase (ChEt) have been immobilized onto this PPY– MWCNT/ITO nanocomposite electrode using N‐ethyl‐N‐(3‐dimethylaminopropyl) carbodiimide and N‐hydroxy succinimide chemistry for estimation of esterified cholesterol. The ChEt–ChOx/PPY–MWCNT/PTS/ITO bioelectrode has been characterized using Fourier transform infrared spectroscopy, electrochemical techniques, and scanning electron microscope. This ChEt–ChOx/PPY–MWCNT/PTS/ITO nanobioelectrode has a response time of about 9 s, linearity of 4 × 10^?4 to 6.5 × 10^?3 M/l of cholesterol oleate concentration, K_m of 0.02 mM, and thermal stability of upto 45°C. This electrode exhibits improved biosensing characteristics compared with other total cholesterol electrodes reported in literature till date and can be used to estimate cholesterol in blood serum samples. Copyright © 2011 John Wiley & Sons, Ltd.     

花生油存在下胆固醇氧化产物研究

探讨了温度、加热时间、花生油的量对胆固溶氧化的影响情况。用毛细管气相色谱法检出6种胆固溶氧化物。在一定范围内，氧化产物的组成和含量随加热温度升高和加热时间延长明显增加，而随着花生油量增加有明显减小的趋势。     

胆固醇对卵磷脂有序体中生成CaCO3晶型的影响

报道了在卵磷脂、胆固醇、橄榄油、电解质溶液组成的分子有序组合体中,胆固醇的加入影响了有序体的膜结构、表面特性,从而也影响到有序体微环境中所生成的CaCO₃晶体结构。随着胆固醇含量增加,在一定范围内球霰石的相对含量增大;油包水体系中生成的球霰石相对含量远大于水包油体系中生成的球霰石相对含量。     

Kinetics of cholesterol oxidation by cholesterol oxidase

Kinetic studies of cholesterol oxidation catalyzed by soluble cholesterol oxidase fromBrevibacterium were conducted. The optimum temperature and pH were found to be 40–45°C and 7.0, respectively. A plot of initial reaction rate versus cholesterol concentration is sigmoidal in shape. Analysis of the data suggests that the reaction follows a concerted model and not a stepwise model.     

Cyclodextrins as hosts for poorly water-soluble compounds in enzyme catalysis

The capability of cyclodextrins to enhance greatly the solubility in water of poorly water-soluble substances makes them an ideal alter native for investigating the expression of enzyme activity with such substrates in aqueous solution. This capability is demonstrated by using soybean lipoxygenase with linoleic acid/β-cyclodextrin and di ethylstilbestrol/γ-cyclodextrin, and cholesterol oxidase with choles terol/methyl-β-cyclodextrin.     

New Amperometric Cholesterol Biosensors Using Poly(ethyleneoxide) Conducting Polymers

Accumulation of cholesterol in human blood can cause several health problems such as heart disease, coronary artery disease, arteriosclerosis, hypertension, cerebral thrombosis, etc. Therefore, simple and fast cholesterol determination in blood is clinically important. In this study, two types of amperometric cholesterol biosensors were designed by physically entrapping cholesterol oxidase in conducting polymers; thiophene capped poly(ethyleneoxide)/polypyrrole (PEO-co-PPy) and 3-methylthienyl methacrylate-co-p-vinyl benzyloxy poly(ethyleneoxide)/polypyrrole (CP-co-PPy). PEO-co-PPy and CP-co-PPy were synthesized electrochemically and cholesterol oxidase was immobilized by entrapment during electropolymerization. The amperometric responses of the enzyme electrodes were measured by monitoring oxidation current of H₂O₂ at +0.7 V in the absence of a mediator. Kinetic parameters, such as Km and Imax, operational and storage stabilities, effects of pH and temperature were determined for both entrapment supports. Km values were found as 1.47 and 5.16 mM for PEO-co-PPy and CP-co-PPy enzyme electrodes, respectively. By using these Km values, it can be observed that ChOx immobilized in PEO-co-PPy shows higher affinity towards the substrate.     

One-pot solid phase selective aromatization of cholesterol using N-bromosuccinimide: an optimized green methodology

One-pot silica promoted selective aromatization of ring-A of cholesterol using N-bromosuccinimide (NBS) has been performed. The structure of the compound has been characterized by spectral analysis (UV, FT-IR, NMR, and Mass).