胆固醇与人体健康

本文论述了人体内胆固醇的分布、主要生理功能、血胆固醇含量与动脉粥样硬化等疾病的关系,同时还介绍了降低血胆固醇含量的途径和措施.     

内蒙古师范大学中老年教职工血脂、血糖指标检测结果分析

对内蒙古师范大学840名中老年教职工空腹血糖(SG)、甘油三酯(TG)、总胆固醇(T—CH)的测定结果进行了统计分析。结果表明，男性和女性血糖异常率分别为5．09％和3．95％，男性和女性高甘油三酯症的检出率分别为21．53％和13．98％，均为男性高于女性；男性和女性高总胆固醇检出率分别为7．63％和7．90％，无明显差异，男性和女性上述3项指标的平均值和异常检出率均随年龄增长呈上升趋势，且50岁后变化较明显。     

大豆膳食纤维对成年大鼠腹腔脂肪积累及血脂和血糖水平的影响

运用药理生理学方法，观察了大豆膳食纤维对高血脂成年ＳＤ大鼠的体重增长、腹腔脂肪的积累、血清胆固醇和血糖水平的影响。与对照组比较，在实验的第１４天，高膳食纤维实验组体重增长率为对照组的－２２．７８％，腹腔脂肪重量变化率为－５９．５７％，血清甘油三酯水平变化率为－３０．１１％，血清胆固醇水平变化率为１４．２４％，血糖水平变化率为１０．３９％。结果表明，大豆膳食纤维对控制成年大鼠的体重增长，减少腹腔脂肪的积累，降低高胆固醇和高脂肪摄入后血清甘油三酯和胆固醇含量，以及降低血糖水平具有明显的作用。     

蛋白质、胆固醇对卵磷脂囊泡稳定性的影响

用卵磷脂、胆固醇和蛋白质所形成的囊泡模拟细胞膜,利用Langmuir膜天平、Zeta电势研究卵磷脂、胆固醇和蛋白质分子之间的相互作用,以及通过停留法和TEM等方法从Gemini(双子)表面活性剂对细胞膜结构破坏方面来探讨不同组分对囊泡的稳定性的影响.实验结果表明,囊泡中的蛋白质、胆固醇和卵磷脂分子之间是相互吸引的.相对于卵磷脂囊泡,混合体系囊泡更加稳定.表面活性剂是通过静电吸引力和疏水效应嵌入囊泡的双分子层中,导致囊泡被破坏.通过动力学实验得到Gemini表面活性剂对囊泡破坏过程的活化能,进一步证明加入蛋白质、胆固醇能够使卵磷脂囊泡更加稳定.     

Digoxin and ouabain increase the synthesis of cholesterol in human liver cells

Digoxin and ouabain are steroid drugs that inhibit the Na⁺/K⁺-ATPase, and are widely used in the treatment of heart diseases. They may also have additional effects, such as on metabolism of steroid hormones, although until now no evidence has been provided about the effects of these cardioactive glycosides on the synthesis of cholesterol. Here we report that digoxin and ouabain increased the synthesis of cholesterol in human liver HepG2 cells, enhancing the activity and the expression of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), the rate-limiting enzyme of the cholesterol synthesis. This effect was mediated by the binding of the sterol regulatory element binding protein-2 (SREBP-2) to the HMGCR promoter, and was lost in cells silenced for SREBP-2 or loaded with increasing amounts of cholesterol. Digoxin and ouabain competed with cholesterol for binding to the SREBP-cleavage-activating protein, and are critical regulators of cholesterol synthesis in human liver cells. Received 10 January 2009; received after revision 11 February 2009; accepted 6 March 2009     

Apolipoprotein M affecting lipid metabolism or just catching a ride with lipoproteins in the circulation?

Apolipoprotein M (apoM) is a novel apolipoprotein found mainly in high-density lipoproteins (HDL). Its function is yet to be defined. ApoM (25 kDa) has a typical lipocalin ?-barrel fold and a hydrophobic pocket. Retinoids bind apoM but with low affinity and may not be the natural ligands. ApoM retains its signal peptide, which serves as a hydrophobic anchor to the lipoproteins. This prevents apoM from being lost in the urine. Approximately 5% of HDL carries an apoM molecule. ApoM in plasma (1 μM) correlates strongly with both low-density lipoprotein (LDL) and HDL cholesterol, suggesting a link to cholesterol metabolism. However, in casecontrol studies, apoM levels in patients with coronary heart disease (CHD) and controls were similar, suggesting apoM levels not to affect the risk for CHD in humans. Experiments in transgenic mice suggested apoM to have antiatherogenic properties; possible mechanisms include increased formation of pre-? HDL, enhanced cholesterol mobilization from foam cells, and increased antioxidant properties. Received 28 November 2008; received after revision 15 December 2008; accepted 16 December 2008     

双胆固醇取代Schiff碱衍生物的合成及其自组装性质

设计合成了双胆固醇取代Schiff碱衍生物, 发现该化合物能在苯、 CCl₄、 乙酸丁酯和DMF中自组装形成透明的有机凝胶. 扫描电镜和透射电镜照片表明, 大量一维凝胶纤维的交叉缠绕构成了三维网络结构. UV-vis吸收光谱表明, 在凝胶相中Schiff碱基团之间通过π-π相互作用形成了H-聚集体.     

黄粉虫对血清总胆固醇及甘油二酯的作用

利用黄粉虫的幼虫含较多亚油酸成分，喂正常迪卡公鸡，并对它的血清总胆固醇及甘油三酯的作用进行研究．试验动物随机分成３组，Ｉ组为对照组，Ⅱ组为黄粉虫幼虫组，６ｇ／ｄ，Ⅲ组为复方亚油酸乙酯丸组，１丸（含亚油酸乙酯３００ｍｇ）／ｄ，实验期１８ｄ．结果表明，血清总胆固醇，Ⅱ组为（２．７３±０．２６）ｍｍｏｌ／Ｌ，Ⅲ组为（２．８３±０．３１）ｍｍｏｌ／Ｌ，均明显低于对照组（３．４０±０．６）ｍｍｏｌ／Ｌ，Ｐ＜０．０１）．血清甘油三酯，Ⅱ组为（０．４０±０．１３）ｍｍｏｌ／Ｌ，Ⅲ组为（０．３６±０．１１）ｍｍｏｌ／Ｌ，均明显低于对照组（（０．９±０．３）ｍｍｏｌ／Ｌ，Ｐ＜０．０１）．试验说明用黄粉虫的幼虫喂迪卡公鸡有显著降低血清总胆固醇和甘油三酯作用．     

7个山东地方品种鸡蛋品质的比较

测定了7个山东地方品种鸡所产的种蛋各15枚的蛋重、蛋密度、蛋形指数、蛋壳厚度、蛋黄色泽、蛋壳相对重、蛋黄相对重、蛋白相对重、蛋黄蛋白比、蛋黄指数、哈夫单位以及全蛋胆固醇含量等蛋品质的指标.结果表明:各品种鸡蛋的蛋黄指数、蛋密度、蛋黄含水量、蛋白含水量4个指标无显著差异(P>0.05);日照麻鸡蛋的蛋重、蛋白相对重2项指标均不同程度地高于其他6个品种鸡;鲁西斗鸡蛋的蛋形指数、蛋黄色泽、蛋壳厚度、蛋黄相对重、蛋黄蛋白比5项指标均不同程度地优于其他6个品种鸡;琅琊鸡蛋的哈夫单位不同程度地优于其他6个品种鸡,全蛋胆固醇含量不同程度地高于其他6个品种鸡;芦花鸡蛋的蛋壳相对重显著高于其他6个品种鸡;综合各项指标,从蛋品质改良的角度来看,日照麻鸡、鲁西斗鸡蛋品质较好.研究结果为进一步开发利用品种资源提供了参考依据.