饱和及多不饱和脂肪酸对金黄地鼠肝LDL受体影响的研究

雄性金黄地鼠６０只随机分成４组：Ｃ１组（对照组），Ｃ２组（胆固醇组），Ｓ组（胆固醇加饱和脂肪酸组）及Ｐ组（胆固醇加多不饱和脂肪酸组）。选用玉米油为多不饱和脂肪酸和猪油为饱和脂肪酸的来源，５周后进行血脂测定和肝ＬＤＬ受体分析。结果表明：在等量胆固醇条件下，和Ｃ２组比较，多不饱和脂肪酸可显著降低血清甘油三酯，总胆固醇，低密度脂蛋白胆固醇和极低密度脂蛋白胆固醇，而高密度脂蛋白胆固醇则升高，饱和脂肪酸使这     

低密度脂蛋白受体限制性片段长度多态性研究进展

低密度脂蛋白受体（ＬＤＬ－Ｒ）基因突变是导致个体罹患家族性高胆固醇血症（ＦＨ）的主要病因，本综述了ＬＤＬ－Ｒ基因限制性片段长度多态性（ＲＦＬＰ）在ＦＨ诊断中的应用，正常人群中ＬＤＬ－Ｒ基因ＲＦＬＰ对血清脂质水平的影响；并就ＬＤＬ－Ｒ基因ＲＦＬＰ和其他疾病的关系作一简要介绍。     

家族性高胆固醇血症患者低密度脂蛋白受体基因的新变异

家族性高胆固醇血症 (familial hypercholesterolemia,FH)的最早报道见于 1938年 ,其临床表现为 :血胆固醇、尤其是低密度脂蛋白 (low density lipoprotein,L DL)胆固醇明显增高 ,皮肤及跟腱黄色瘤和早发冠心病。 1974年 ,Goldstein和Brown[1 ]发现了成纤维细胞表面的低密度脂蛋白受体 ,并由此阐明了 FH的发病机理在于编码 L DL 受体的基因发生了突变 ,引起 L DL受体功能异常。我们对 1例 FH纯合子进行了研究 ,发现了 2个新的点突变。1　病例与方法1.1　患儿　男 ,11岁 ,因皮下结节并进行性增多 8年 ,心前区疼痛 2年就诊。查体 :眼睑…     

生长因子对成纤维细胞合成低密度脂蛋白受体的影响

用免疫印迹方法,以抗LDL受体的抗体为探针,直接检测细胞膜蛋白中的LDL受体蛋白,并对受体蛋白进行定量。用本方法分析了生长因子(PDGF)对培养的人成纤维细胞合成LDL受体的影响,结果表明,在PDGF作用4小时以后,细胞合成LDL受体始出现增加,8小时为对照细胞的2.2倍,至16小时增加至5倍。提示PDGF的作用机制是在基因转录水平。     

家族性高胆固醇血症家系低密度脂蛋白受体基因剪接突变的研究

目的　检测中国汉族家族性高胆固醇血症 (familial hypercholesterolemia,FH)大家系低密度脂蛋白受体 (low density lipoprotein receptor,L DL R)基因突变 ,探讨 FH发病的分子机理。方法　首先采用聚合酶链反应 -限制性片段长度多态性 (polymerase chain reaction- restriction fragment lengthpolymorphism,PCR- RFL P)技术检测载脂蛋白 B1 0 0 (apo B1 0 0 )基因 Q35 0 0 R突变 ,排除家族性 apo B1 0 0 缺陷症 ,再采用 PCR扩增结合核苷酸序列分析检测 1例临床诊断为 FH纯合子患儿及其家系成员 L DL R基因启动子和全部 18个外显子片段 ,结果与 Gen Bank公布的该基因正常序列对比找出突变 ,并在家系其他成员中证实该突变。结果　该患儿 L DL R基因第 3内含子剪接供体处存在 IN 5′GT→AT纯合剪接突变 ,并且在家系中得到证实 ,一级和二级亲属中各发现 2例相同位点和相同形式的杂合子 ,其基因型表现为野生型和突变型杂合现象。同时未检测出患儿及其父母 apo B1 0 0 Q35 0 0 R突变。结论　发现 L DL R基因第 3内含子 G→ A纯合剪接突变 ,可能是该 FH家系发病的分子基础 ;检测该突变对临床干预和遗传指导有参考价值。     

一个家族性高胆固醇血症家系的低密度脂蛋白受体基因突变检测与功能分析

目的 检测一个家族性高胆固醇血症(familial hypercholesterolemia,FH)患者低密度脂蛋白受体(low density lipoprotein receptor,LDLR)的基因突变,并对淋巴细胞表面LDLR功能进行检测.方法 以一家系中4例临床诊断为FH患者的基因组DNA为模板,首先检测载脂蛋白B-100(apolipoprotein B-100,ApoB100)基因R3500Q突变,以排除家族性ApoB100缺陷症(familial defective apolipoprotein B-100,FDB).然后用降落PCR方法,扩增LDLR基因的启动子和外显子片段,用单链构象多态性方法进行分析,对可疑外显子的PCR产物进行T/A克隆,测序分析.同时,用人淋巴细胞与荧光探针DiI标记的低密度脂蛋白发生结合反应,再通过流式细胞仪检测,显示具有功能性LDLR的淋巴细胞比例.结果 该家系患者LDLR基因第10外显子均出现杂合突变,第462位密码子由TGG突变为TAG,导致在462位提前出现终止密码子(W462X).具有功能性LDLR的淋巴细胞占总淋巴细胞比例患者为63.7%,健康对照者为77.3%,患者淋巴细胞LDLR活性约为健康对照者的82.4%,出现一定程度的降低.结论 提示LDLR基因W462X突变可能是导致本FH家系患者患病的一个主要原因.     

低密度脂蛋白受体基因与家族性高胆固醇血症

低密度脂蛋白受体基因突变可导致家族性高胆固醇血ＦＨ是一种多基因遗传病，并且受环境因素的影响，本文重点讨论ＬＤＬＲ基因突变与家族性高胆固醇血症的关系。     

低密度脂蛋白受体限制性片段长度多态性研究进展

低密度脂蛋白受体（LDL－R）基因突变是导致个体罹患家族性高胆固醇血症（FH）的主要病因。本文综述了LDL-R基因限制性片段长度多态性（RFLP）在FH诊断中的应用；正常人群中LDL-R基因RFLP对血清脂质水平的影响；并就LDL－R基因RFLP和其他疾病的关系作一简要介绍。     

叙利亚地鼠原始生殖细胞体外培养方法的初步研究

为建立叙利亚地鼠原始生殖细胞的体外培养方法．在体外无菌分离孕龄10．5d的叙利亚地鼠胚胎的生殖嵴，采用酶机械分离方法获取原始生殖细胞，在条件培养基中培养于饲养层细胞上，然后用酶组织化学染色方法鉴定碱性磷酸酶（ALP）的活性。去除分化抑制因素并诱导原始生殖细胞体外分化后．观察拟胚体和分化细胞的产生。实验结果显示孕龄10．5d的地鼠胚胎生殖嵴．用酶机械分离方法能成功地分离出具有发育多能性的原始生殖细胞，ALP染色鉴定呈强阳性，体外诱导分化后可观察到3种胚层来源的细胞。结果提示该细胞体外培养体系的建立，为生物医学工程学提供了一种新的细胞来源。     

阿魏酸钠对高脂血症致动脉粥样硬化过程中胆固醇和甘油三酯代谢的影响

目的：观察阿魏酸钠(SF)对高脂血症引起的动脉粥样硬化(AS)过程中胆固醇和甘油三酯代谢的影响，进一步探讨其抗动脉粥样硬化的作用机制。方法: 高胆固醇喂养复制AS动物模型；以氧化型低密度脂蛋白（ox-LDL）与小鼠巨噬细胞株RAW264.7细胞体外共培养，诱导建立泡沫细胞模型，与人肝母细胞瘤细胞株HepG2细胞体外共培养，建立损伤细胞模型；分别给予SF进行干预。检测实验动物AS斑块面积和血脂水平，油红O染色观察RAW264.7细胞内脂质堆积情况，高效液相色谱定量分析RAW264.7细胞内胆固醇的含量，逆转录聚合酶链反应（RT-PCR）测定HepG2细胞肝脂酶（HL）mRNA的表达水平。结果: (1)与高脂组相比，高脂+SF组动物主动脉粥样斑块面积明显减小（P<0.01），血浆甘油三酯水平显著降低（P<0.01），但血浆胆固醇水平无明显改变（P>0.05）；(2) 与ox-LDL组相比，ox-LDL+SF处理组中HepG2细胞HL mRNA表达水平显著增加（P<0.01），但RAW264.7细胞内胆固醇含量无明显改变（P>0.05）。结论: SF能降低高胆固醇导致的AS斑块面积，具有抗动脉粥样硬化的作用，其作用机制可能与上调HL mRNA表达水平从而降低血浆甘油三酯水平有关，而与血浆胆固醇水平和ox-LDL诱导的巨噬泡沫细胞形成无关。提示血浆甘油三酯升高是AS的独立危险因素，HL介导的甘油三酯代谢途径可能是AS治疗的潜在靶点。     

治疗家族性高胆固醇血症时合成短肽在去除血中LDL的应用

简要地介绍了从血液中分离低密度脂蛋白(LDL)技术的适应症，并对LDL吸附系统作了简单回顾，主要从合成短肽在去除血中LDL的应用出发，介绍了4种新型吸附剂配体(短肽)的不同设计原理：(1)利用静电吸引力的原理设计了带正电荷的短肽；(2)根据LDL受体的配体结合位点肽段的特征设计短肽；(3)制备具有Lp(a)特征的短肽作为免疫原获取Lp(a)抗体；(4)用基因工程的方法人工合成低密度脂蛋白接合蛋白(LBPs)片断用于与LDL的特异性结合。接着介绍了对吸附剂载体的设计要求。最后从合成短肽的角度出发，对血液净化法治疗家族性高脂血症作了展望。     

Eight novel mutations and functional impairments of the LDL receptor in familial hypercholesterolemia in the north of Japan

In the course of investigations of familial coronary artery disease in Hokkaido, the northland of Japan, we identified 13 families affected by familial hypercholesterolemia. Among them, we identified eight novel mutations of the low-density lipoprotein (LDL) receptor gene, four of which caused frameshifts: (1) a 7-bp deletion at nucleotide (nt) 578–584 (codon 172–174, exon 4); (2) a 14-bp insertion at 682 nt (codon 207–208, exon 4); (3) a 49-bp deletion at nt 943–991 (codon 294–310, exon 7); and (4) a one-base insertion of C to a stretch of C₃ at nucleotides 1687–1689 or codon 542. The others included (5) a T-to-C transition at nt 1072 causing substitution of Cys for Arg at codon 337 (C337R, exon 8); (6) a splice-site G-to-T substitution in intron 11; (7) a splice-site G-to-C substitution in intron 11; and (8) a G-to-T transition at nt 1731 causing substitution of Trp for Cys at codon 556 (W556C, exon 12). To disclose the functional consequences of novel mutations, we characterized each of these mutations by two assays in peripheral lymphocytes, i.e., uptake of fluorescently labeled LDL by LDL receptors, and measurement of cell surface-bound LDL receptor protein using specific monoclonal antibody against LDL receptor. Received: September 27, 2001 / Accepted: November 12, 2001     

Effect of the StuI polymorphism in the LDL receptor gene (Ala 370 to Thr) on lipid levels in healthy individuals

We have examined the effect on plasma lipid levels of a single base change in exon 8 of the LDL receptor gene that causes an amino acid change Ala 370 to Thr in a sample of 318 Icelandic individuals selected at random from the general population. The change destroys a Stu I restriction site and was detected by digestion of pooled samples in groups of 5. The frequency of the loss of the cutting site was 0.05 (95%CI=0.014-0.054). In men, those with the Thr allele (n=18) had 8.3% higher total cholesterol, 11.8% higher LDL cholesterol and 10.3% higher apolipoprotein B than those with the common Ala allele, whereas in women those with the Thr allele (n=12) had levels lower by 7.4%, 13.3% and 10.1% respectively. These differences reached statistical significance only in the men (p<0.05). Functional analysis of CHO cells transfected with constructs of the LDL receptor cDNA carrying the Ala370 and Thr370 alleles showed that within the limits of the assays there was no difference in function of the LDL receptor protein as measured by uptake and degradation of LDL. The data raise the possibility that amino acid substitutions that could affect LDL receptor function below the limits of detection by conventional assays, may have an effect on plasma lipid levels in the general population.     

Influence of Pulsatile Flow on LDL Transport in the Arterial Wall

The accumulation of low-density lipoprotein (LDL) is one of the important factors in atherogenesis. Two different time scales may influence LDL transport in vivo: (1) LDL transport is coupled to blood flow with a pulse cycle of around 1 s in humans; (2) LDL transport within the arterial wall is mediated by transmural flow in the order of 10⁻⁸ m/s. Most existing models have assumed steady flow conditions and overlooked the interactions between physical phenomena with different time scales. The objective of this study was to investigate the influence of pulsatile flow on LDL transport and examine the validity of steady flow assumption. The effect of pulsatile flow on transmural transport was incorporated by using a lumen-free cyclic (LFC) and a lumen-free time-averaged (LFTA) procedures. It is found that the steady flow simulation predicted a focal distribution in the post-stenotic region, differing from the diffuse distribution pattern produced by the pulsatile flow simulation. The LFTA procedure, in which time-averaged shear-dependent transport properties calculated from instantaneous wall shear stress (WSS) were used, predicted a similar distribution pattern to the LFC simulations. We conclude that the steady flow assumption is inadequate and instantaneous hemodynamic conditions have important influence on LDL transmural transport in arterial geometries with disturbed and complicated flow patterns.     

洛伐地汀对高糖和低密度脂蛋白所致肾小管上皮细胞外基质蓄积的改善作用

为探讨洛伐他汀对高糖环境和低密度脂蛋白（LDL）刺激下人肾小管上皮细胞外基质（ECM）蓄积的作用。经体外培养人肾脏近端小管上皮细胞（HKC）,分别用LDL和/或高糖刺激HKC细胞,并与洛伐他汀共孵育。采用^3H-脯氨酸参入法测定总胶原合成,ELISA方法测定细胞培养上清中IV型胶原和板层素浓度,RT-PCR技术观察HKC细胞中IV型胶原及纤维连接蛋白（FIV）mRNA表达。结果表明高糖和LDL均可增加HKC细胞培养上清中的IV型胶原和板层素水平,并能上调IV型胶原和FN mRNA的表达,洛伐他汀可以部分或全部逆转高糖和LDL的作用。说明高糖和LDL均可促使HKC细胞合成细胞外基质,洛伐他汀可以逆转它们的作用。     

低氧对大鼠肺组织中介素及其受体系统表达的影响

目的探讨低氧对大鼠肺组织中介素/肾上腺髓质素2(IMD/ADM2)及其受体系统[降钙素受体样受体(CRLR)和受体活性修饰蛋白(RAMPs)]的变化及意义。方法清洁级雄性SD大鼠20只随机均分成对照组和低氧组。采用放免法检测血浆与肺组织中IMD/ADM2及其横向同源物ADM的含量,RT-PCR技术检测肺组织中IMD/ADM2、ADM及其受体系统mRNA的表达。结果①低氧组大鼠平均肺动脉压、右心室与左心室加室间隔重量比[RV/(LV S)]显著高于对照组(P<0.01);②低氧组大鼠肺组织中IMD/ADM2含量显著低于对照组(P<0.01),而ADM含量却显著高于对照组(P<0.01);血浆IMD/ADM2浓度低氧组显著高于对照组(P<0.01);③低氧组大鼠肺组织中IMD/ADM2和ADM mRNA水平均显著高于对照组(P<0.05),而RAMP1 mRNA水平显著低于对照组(P<0.01)。结论在大鼠低氧性肺动脉高压的形成过程中的早期阶段,IMD/ADM2蛋白和基因的表达存在差异性,而RAMP1基因表达下调。     

Influence of Tribulus terrestris extract on lipid profile and endothelial structure in developing atherosclerotic lesions in the aorta of rabbits on a high-cholesterol diet

The aim of this study was to investigate the pleotropic effects of an extract of a traditional herb, Tribulus terrestris (TT), on the lipid profile and vascular endothelium of the abdominal aorta in New Zealand rabbits fed a cholesterol-rich diet. Eighteen rabbits were randomly divided into three groups (n=6 for each). One experimental group (EG-I) was given a cholesterol-rich diet, a second experimental group (EG-II) was treated with TT following a cholesterol-rich diet, and a control group (CG) was fed a standard diet. Blood samples were collected on day 0 and then at weeks 4 and 12 to determine total serum cholesterol (TC), high density lipid-cholesterol (HDL-C), low density lipid-cholesterol (LDL-C) and triglyceride (TG) levels. Tissues were collected from the abdominal aorta for immunohistochemistry and transmission and scanning electron microscopy. In EG-II, the serum lipid profile was significantly lower than that of EG-I at week 12 with a reduction of TC: 65%; LDL-C: 66%; HDL-C: 64%; TG: 55%. Ultrastructural analysis revealed that endothelial damage was more prominent in EG-I compared to EG-II. The ruptured endothelial linings and damaged cellular surfaces increased in EG-I compared to EG-II. Our data indicate that dietary intake of TT can significantly lower serum lipid profiles, decrease endothelial cellular surface damage and rupture and may partially repair the endothelial dysfunction resulting from hyperlipidemia.