某天然矿泉水对实验性高脂大鼠血脂水平的影响

目的探讨预防性饮用某天然矿泉水对实验性高脂大鼠血脂水平的影响。方法 28只5周龄的雌性清洁级SD大鼠禁食12h后,内眦采血,测血清中的胆固醇(TC),根据TC水平随机分为高脂模型实验组和高脂模型对照组,每组14只。饲喂髙脂饲料的同时,高脂模型实验组自由饮用某天然矿泉水,高脂模型对照组自由饮用自来水,饮用某天然矿泉水第30 d和40 d,分别禁食12 h后,内眦采血,Autolab 1.0全自动生化分析仪测定血清胆固醇(TC)、甘油三脂(TG)和高密度脂蛋白(HDL-C)水平。结果饮用某天然矿泉水第30 d,高脂模型实验组大鼠血清中TG水平与对照组相比显著降低,差异显著(P0.05),TC和HDL-C水平无显著性差异;第40 d时高脂模型实验组大鼠血清中TG水平与对照组相比极显著降低,差异极显著(P0.01),同时统计学分析表明该天然矿泉水虽未降低TC水平和提高HDL-C水平,但饮用该天然矿泉水后雌性大鼠TC水平有下降的趋势并且HDL-C水平有升高的趋势,而自来水组雌性大鼠TC水平较第30 d时呈现增加的趋势。结论某天然矿泉水具有改善实验性雌性高脂大鼠血脂的趋势。     

超临界CO2萃取蛋黄中胆固醇和甘油三脂的研究

经过对现有的脱除方法进行利弊分析,确定采用超临界CO2萃取技术脱除蛋黄中的胆固醇和甘油三脂．着重对脱除工艺中的萃取压力的确定进行实验研究,并确定了其较佳的萃取压力为24MPa．     

皂荚素对大鼠DNA损伤的干预及对血清胆固醇的影响

为了探究皂荚素对高胆固醇模型大鼠抗氧化能力和DNA损伤以及对大鼠血浆胆固醇及相关血脂生化指标的影响,将48只健康大鼠,随机分为对照组、低浓度皂荚素组和高浓度皂荚素组,各组分别喂饲皂荚素质量比分别为0,80,200 mg/kg的饲料,制作由不同浓度H₂O₂(0,6,12,18 μmol/L)诱导的DNA损伤兼高胆固醇大鼠模型.实验期限为60 d,实验结束采血,应用试剂盒检测血清丙二醛(MDA)水平和谷胱甘肽过氧化物酶(GSH-PX)活性,并采用单细胞凝胶电泳法测定淋巴细胞DNA的损伤情况.结果显示,与对照组比较,低浓度皂荚素组、高浓度皂荚素组MDA含量和血清GSH活性差异均具有统计学意义;低浓度皂荚素组和高浓度皂荚素组大鼠血清总胆固醇TC、甘油三酯(TG)、载脂蛋白B(apoB)的含量都有明显的降低,尤其以高浓度皂荚素组最为显著;两组大鼠的胆汁酸排泄量增加,载脂蛋白A-Ⅰ(apoA-Ⅰ)、高密度脂蛋白-胆固醇(HDL-C)水平影响差异无统计学意义.说明皂荚素可有效降低血浆胆固醇水平,对于健康幼年大鼠血清GSH及脂质过氧化产物MDA含量有显著影响,对H₂O₂诱导的DNA损伤也表现出明显的保护作用.     

Pore-forming toxins

Pore-forming toxins are widely distributed proteins which form lesions in biological membranes. In this review, bacterial pore-forming toxins are treated as a paradigm and discussed in terms of the structural principles on which they work. Then, a large family of bacterial toxins, the cholesterol-binding toxins, are analyzed in depth to provide an overview of the processes involved in pore formation. The ways in which the cholesterol-binding toxins (cholesterol-dependent cytolysins) interact with membranes and form pores, the structure of the monomeric soluble and oligomeric pore-forming states, and the effects of the toxin on membrane structure are discussed. By surveying the range of work which has been done on cholesterol-binding toxins, a working model is elaborated which reconciles two current, apparently diametrically opposed, models for their mechanism. Received 7 September 2001; received after revision 12 November 2001; accepted 5 December 2001     

ABCA2: a candidate regulator of neural transmembrane lipid transport

Studies in the past years have implicated multispan transmembrane transport molecules of the ATP binding cassette (ABC) transporter family in cellular lipid export processes. The prototypic ABC transporter ABCA1 has recently been demonstrated to act as a major facilitator of cellular cholesterol and phospholipid export. Moreover, the transporter ABCA4 (ABCR) plays a pivotal role in retinaldehyde processing, and ABCA3 has recently implicated in lung surfactant processing. These pioneering observations have directed considerable attention to the A subfamily of ABC proteins. ABCA2 is the codefining member of the ABC A-transporter subclass. Although known for some time, it was not until recently that its complete molecular structure was established. Unlike other ABC A-subfamily members, ABCA2 is predominantly expressed in the brain and neural tissues. The unique expression profile together with available structural data suggest roles for this largest known ABC protein in neural transmembrane lipid export. Received 31 January 2002; received after revision 11 March 2002; accepted 11 March 2002     

泽泻水提取物、醇提取物对小鼠脂代谢影响的比较

利用高脂饲料建立实验小鼠肥胖模型，然后灌胃泽泻水提物、醇提物，10d后检测血清中总胆固醇(TC)、甘油三酯(TG)及高密度脂蛋白-胆固醇(HDL-C)的浓度．比较泽泻水提物与醇提物对肥胖小鼠血清中TC，TG及HDL-C浓度的影响．结果表明：泽泻水提物、醇提物均能明显降低肥胖小鼠模型血清中TC，TG的浓度，升高HDL-C的浓度．提示泽泻水提物和醇提物对肥胖小鼠均有降血脂的作用，但两对脂代谢的影响没有明显的优劣差异．     

苦丁茶降血脂作用的研究

对实验性高血脂小鼠分别用１．２％和２．４％的苦丁茶水灌胃４５ｄ后，取尾血测定其血清总胆固醇（ＴＣ）、甘油三酯（ＴＧ）、高密度脂蛋白胆固醇（ＨＤＬ－ｃ）含量和卵磷脂胆固醇酰基转移酶（ＬＣＡＴ）的相对活性，并计算出低密度脂蛋白胆固醇（ＬＤＬ－ｃ）和极低密度脂蛋白胆固醇（ＶＬＤＬ－ｃ）浓度及动脉硬化指数（ＡＩ），并与绞股蓝茶的降脂作用进行比较。结果表明，饮用苦丁茶可以明显降低实验性高血脂小鼠的ＴＣ、ＴＧ和ＬＤＬ－ｃ、ＶＬＤＬ－ｃ（Ｐ＜０．０１或Ｐ＜０．０５），显著升高ＨＤＬ－ｃ含量及ＨＤＬ－ｃ／ＴＣ（Ｐ＜０．０１或Ｐ＜０．０５），而作为阳性对照的绞股蓝茶组ＨＤＬ－ｃ与高脂组比较无显著差异．二个苦丁茶组与绞股蓝茶组的ＬＤＬ－ｃ／ＨＤＬ－ｃ及ＬＣＡＴ相对活性均与高脂组有显著差异（Ｐ＜０．０１），与对照组则无明显差异。由此说明，苦丁茶具有降血脂、防治动脉粥样硬化的作用，提示苦丁茶的降脂机理与其能够升高ＬＣＡＴ相对活性有关。     

Emblica officinalis reduces serum,aortic and hepatic cholesterol in rabbits

Summary Emblica officinalis reduced serum cholesterol (p<0.001), aortic cholesterol (p<0.001) and hepatic cholesterol (p<0.001) significantly in rabbits.Emblica officinalis did not influence euglobulin clot lysis time, platelet adhesiveness or serum triglyceride levels.     

Molecular basis of Alzheimer's disease

Despite an exponential production of data, Alzheimer's disease (AD) remains an enigma. Unresolved questions persist in the face of the heterogeneity of this neuropathology. Recent progress in understanding mechanisms for AD results from the study of amyloid precursor protein (APP) metabolism and the involvement of senile plaque-associated proteins. In addition to the amyloid cascade hypothesis, alternative schemes emerge, in which the amyloid peptide is not the primary effector of the disease. Perturbations of vesicular trafficking, the cytoskeletal network, and membrane cholesterol distribution could be central events. Furthermore, since the physiological role of APP, presenilins, and apolipoprotein E in the central nervous system are not completely understood, their involvement in AD etiology remains speculative. New actors have to be found to try to explain sporadic cases and non-elucidated familial cases.