高效液相色谱评价血清胆固醇试剂中酶的性能

为了评价国内市场上血清胆固醇试剂中胆固醇酯酶（ＣＥＨ）和胆固醇氧化酶（ＣＯＤ）的性能，设计了测定反应液（血清加试剂）中未被水解的胆固醇酯（ＵＨＣＥ）和未被氧化的游离胆固醇（ＵＯＦＣ）的方法。该法用正己烷提取未经皂化的和皂化的反应液中的游离胆固醇，衍生为苯氨基甲酸酯，高效液相色谱测定其含量。未经皂化的反应液中的游离胆固醇是ＵＯＦＣ，皂化后的反应液中的游离胆固醇是ＵＯＦＣ与ＵＨＣＥ之和，从中减去ＵＯＦ     

抗坏血酸氧化酶在TRINDER反应中抗VC干扰应用评价

临床生化许多检测项目都应用了Ｔｒｉｎｄｅｒ反应,如葡萄糖（ＧＬＵ）、甘油三脂（ＴＧ）、胆固醇（ＣＨＯＬ）、尿酸（ＵＡ）。其原理为被测物质通过酶作用产生的过氧化氢（Ｈ２Ｏ２）在４—氨基替比林（４－ＡＡＰ）、过氧化物酶（ＰＯＤ）的存在下,可生成红色醌亚胺...     

范可尼贫血互补群 Ｄ２ 基因突变与卵巢上皮癌患者行 新辅助化疗疗效及预后的相关性

摘要：目的 分析范可尼贫血互补群 Ｄ２（ｆａｎｃｏｎｉ ａｎｅｍｉａ ｃｏｍｐｌｅｍｅｎｔａｔｉｏｎ ｇｒｏｕｐ Ｄ２，ＦＡＮＣＤ２）突变与卵巢上皮癌（ｅｐｉｔｈｅｌｉａｌ ｏｖａｒ ｉａｎ ｃａｎｃｅｒ，ＥＯＣ）患者行新辅助化疗（ｎｅｏａｄｊｕｖａｎｔ ｃｈｅｍｏｔｈｅｒａｐｙ，ＮＡＣＴ）后的疗效及预后的相关性。方法 选取２０１７ 年４ 月至 ２０１９ 年 ４ 月兵器工业五二一医院收治的 １８４ 例 ＥＯＣ 患者为研究对象，取穿刺活检组织并提取 ＤＮＡ，采用实时荧光定量 ＰＣＲ 检测患者 ＦＡＮＣＤ２ 基因的突变情况，分析 ＦＡＮＣＤ２ 基因突变与 ＥＯＣ 患者临床病理参数的相关性；进一步分析 ＦＡＮＣＤ２ 突变 与 ＮＡＣＴ 治疗４ 周后的疗效及预后的关系。结果 实时荧光定量 ＰＣＲ 结果表明，ＦＡＮＣＤ２ 基因突变率为４２．３９％。ＦＡＮＣＤ２ 突 变型与野生型 ＥＯＣ 患者的肿瘤病灶直径、ＥＣＯＧ 评分、分化程度和病理分型比较的差异具有统计学意义（Ｐ 值分别为 ０．０２４， ０．０３７，＜０．００１，０．００２）。ＦＡＮＣＤ２ 突变型 ＥＯＣ 患者的疾病控制率（ｄｉｓｅａｓｅ ｃｏｎｔｒｏｌ ｒａｔｅ，ＤＣＲ）显著低于 ＦＡＮＣＤ２ 野生型 ＥＯＣ 患者 （６６．６７％ ｖｓ ８３．９６％，χ２ ＝ ７．５０６，Ｐ＝ ０．００６）。１８４ 例 ＥＯＣ 患者的总体生存率为 ６５．２２％，ＦＡＮＣＤ２ 突变型 ＥＯＣ 患者的 ２ 年生存 率显著低于 ＦＡＮＣＤ２ 野生型（３２．０７％ ｖｓ ４２．３１％，ｌｏｇ ｒａｎｋ χ２ ＝ ４．１５２，Ｐ＝ ０．０４２）。Ｃｏｘ 风险比例模型多因素显示，分化程度和病 理分型是 ＦＡＮＣＤ２ 突变的独立影响因素（Ｐ＜０．０５）。运用 Ｋａｐｌａｎ Ｍｅｉｅｒ 法对患者进行单因素生存分析发现，肿瘤大小（Ｐ ＝ ０．０３１）、肿瘤病理分型（Ｐ＜０．００１）、分化程度（Ｐ＜０．００１）、突变型 ＦＡＮＣＤ２ 的表达（Ｐ＝ ０．０４２）与患者的总生存期密切相关。Ｃｏｘ 风险比例模型多因素分析显示，肿瘤病理分型、分化程度和 ＦＡＮＣＤ２ 突变是 ＥＯＣ 患者预后的独立影响因素（Ｐ 值分别为０．０１４， ０．０３５，０．０３６）。结论 ＦＡＮＣＤ２ 基因突变与 ＥＯＣ 患者 ＮＡＣＴ 疗效相关，肿瘤病理分型、分化程度、ＦＡＮＣＤ２ 突变是 ＥＯＣ 患者预 后的独立影响因素。     

脐血CD_(34)~ CD_(19)~－细胞与体外培养集落的相关性分析

用两种单克隆抗体（单抗）标记脐血造血祖细胞表面抗原（ＨＰＣＡ，ＣＤ＿（３４））用流式细胞仪分析，并比较两种单抗标记的细胞与体外培养的粒单细胞集落形成单位（ＣＦＵ－ＧＭ），红系爆式集落形成单位（ＢＦＵ－Ｅ）和混合集落形成单位的相关性，结果表明脐血有核细胞中，抗ＨＰＣＡ－２－ＦＩＴＣ阳性的细胞占１．０５１０．７２％，Ｔｕｋ３（纯抗体）阳性细胞占２．０６±１．２５％，差别显著（Ｐ＜０．０５），每μｌ脐血两种单抗标记的细胞分别为９６．５６±５６．６４和２３１．４０±１６３．９３（Ｐ＜０．０５），变异系数依次为５８．４７％和６８．４３％。尽管抗ＨＰＣＡ－２－ＦＩＴＣ阳性细胞与阳性细胞数量呈显著正相关，但前者与ＣＦＵ－ＧＭ，ＢＦＵ－Ｅ，ＣＦＵ－Ｍｉｘ以及ＣＦＵｓ（ＣＦＵ－ＧＭ＋ＢＦＵ－Ｅ＋ＣＦＵ－Ｍｉｘ）均呈正相关，而后者仅与ＣＦＵ－ＧＭ，ＣＦＵｓ呈正相关。研究结果提示在检测造血祖细胞时，用抗ＨＰＣＡ－２－ＦＩＴＣ代替可降低假阳性，获得较好的细胞与ＣＦＵ间的线性关系。     

3－磷酸甘油脱氢酶偶联法测定血清醛缩酶活性

探讨用３－磷酸甘油脱氢酶偶联法测定血清中醛缩酶（ＡＬＤ）活性的最佳反应条件。反应体系的终末浓度：ＴＥＡ１００ｍｍｏｌ／Ｌ，ＦＤＰ４ｍｍｏｌ／Ｌ，碘乙酸０．２２ｍｍｏｌ／Ｌ，ＮＡＤＨ０．２６ｍｍｏｌ／Ｌ，ＧＤＨ≥１０００Ｕ／Ｌ，ＴＰＩ≥１５００Ｕ／Ｌ，ＬＤ≥１０００Ｕ／Ｌ。最适ｐＨ在７．８～８．０，Ｋｍ为７．２×１０－３ｍｍｏｌ／Ｌ。批内ＣＶ：酶活性在７．３４Ｕ／Ｌ和６５．０６Ｕ／Ｌ时，ＣＶ分别为５．７％和１．４％；批间ＣＶ：酶活性在１１．８９Ｕ／Ｌ和１００．０８Ｕ／Ｌ时，ＣＶ分别为６．０％和３．３％，酶活性线性范围至少可达１８０Ｕ／Ｌ。健康人６０名，ＡＬＤ活性为４．５３±１．１７（ｘ±ｓ）Ｕ／Ｌ，男女两组均值无显著性差异。本文对ＴＥＡ－ＨＣｌ（ｐＨ８．０）、Ｔｒｉｓ－ＨＣｌ（ｐＨ８．０）和Ｃｏｌｉｄｉｎｅ－ＨＣｌ（ｐＨ７．５）三种缓冲液用于ＡＬＤ活性测定效果进行了评价，结果表明在ＴＥＡ缓冲液中所测ＡＬＤ活性最高；ＴＥＡ和Ｃｏｌｉｄｉｎｅ两种缓冲液的浓度在２５～１５０ｍｍｏｌ／Ｌ范围内对ＡＬＤ活性无影响，Ｔｒｉｓ缓冲液在５０ｍｍｏｌ／Ｌ时测得酶活性较高，缓冲液浓度过高或过低，酶活性均有所下降     

^14C标记合成脂蛋白样颗粒法测定血清中胆固醇酯转运蛋白活性

目的 建立测定血清中胆固醇脂转运蛋白（ＣＥＴＰ）活性的方法。方法 用＾１４Ｃ标记的胆固醇酯合成高密度脂蛋白（ＨＤＬ）样颗粒作为反应基质,检测了４５例健康人,５２例冠心病（ＣＨＤ）患者血清ＣＥＴＰ活性。结果 该方法线性范围为０￣３１．８％,高（２６．４％）、低（６．８３％）活性批内变异系数（ＣＶ）分别为６．１％,７．６％,批间ＣＶ分别为１１．７％、１２．１％,５２例ＣＨＤ患者血清ＣＥＴＰ活性（Ｘ＾－     

汉族原发性胆汁性胆管炎患者抗线粒体抗体 Ｍ２ 亚型 抗原表位分布及其临床价值

目的 探讨汉族原发性胆汁性胆管炎（ＰＢＣ）患者抗线粒体抗体 Ｍ２ 亚型（ＡＭＡ?Ｍ２）抗原表位分布情况及其临床价值。 方法 采用 Ｒｅｄ ／ ＥＴ 重组技术制备 ＡＭＡ?Ｍ２ 抗原表位蛋白 ＰＤＣ?Ｅ２、ＢＣＯＡＤＣ?Ｅ２ 和 ＯＧＤＣ?Ｅ２，建立相应的 ＥＬＩＳＡ 检测方法，对 ３７４ 例 ＰＢＣ 患者抗原表位分布进行分析。 比较 ＡＭＡ?Ｍ２ 主要抗原表位组合模式间清蛋白－胆红素评分（ＡＬＢＩ）结果的差异，熊 去氧胆酸（ＵＤＣＡ）药物生化应答和不应答患者抗原表位分布的差异。 结果 ３７４ 例 ＰＢＣ 患者血清与 ＰＤＣ?Ｅ２、ＢＣＯＡＤＣ?Ｅ２ 和 ＯＧＤＣ?Ｅ２ 抗原表位有反应率分别为 ８６．６％、８８．０％和 ３５．０％。 与 ＰＢＣ 患者血清有反应性的常见抗原表位模式（ ＰＤＣ?Ｅ２＋ ＢＣＯＡＤＣ?Ｅ２＋ＯＧＤＣ?Ｅ２、ＰＤＣ?Ｅ２＋ＢＣＯＡＤＣ?Ｅ２、ＰＤＣ?Ｅ２ 和 ＢＣＯＡＤＣ?Ｅ２）间 ＡＬＢＩ 结果的差异有统计学意义（Ｐ＜０．０５），ＵＤＣＡ 生 化不应答患者血清与 ＢＣＯＡＤＣ?Ｅ２ 的反应率（ ８９． ９％） 高于应答患者（ ７７． ９％），差异有统计学意义（ Ｐ ＜ ０． ０５）。 结论 与 ＡＭＡ?Ｍ２抗原表位 ＰＤＣ?Ｅ２、 ＢＣＯＡＤＣ?Ｅ２ 和 ＯＧＤＣ?Ｅ２ 同时有反应性的 ＰＢＣ 患者疾病预后不佳的风险较高， ＰＤＣ?Ｅ２ 和 ＢＣＯＡＤＣ?Ｅ２抗原表位可能与 ＵＤＣＡ 治疗应答相关。     

一种新高频通气方法对实验性急性呼吸窘迫综合征的疗效观察

在高频喷射通气（ＨＦＪＶ）治疗犬实验性急性呼吸窘迫综合征（ＡＲＤＳ）时，采用连续ＨＦＪＶ基础上间歇叠加深吸气（ＨＦＪＶ＋ＤＩ）的新通气方法，以期为ＡＲＤＳ的治疗寻找一种新途径。用油酸复制犬ＡＲＤＳ模型，并随机分为３组。ＨＦＪＶ＋ＤＩ组（ｎ＝１０）：在连续ＨＦＪＶ基础上每隔１０分钟加入１次深吸气；常规机械通气组（ＣＭＶ，ｎ＝１０），给予０．７８５ｋＰａ（１ｋＰａ＝１０．２０ｃｍＨ２Ｏ）呼气末正压（ＰＥＥＰ）治疗；对照组（ｎ＝１０），未予通气治疗。每隔１小时测定１次氧合及血流动力学指标，共观察５小时。注射油酸后，动脉氧分压（ＰａＯ２）由１２．４００ｋＰａ（１ｋＰａ＝７．５ｍｍＨｇ）降至６．５６０ｋＰａ（Ｐ＜０．０１），动脉二氧化碳分压（Ｐａ－ＣＯ２）未见明显变化。通气治疗后，ＣＭＶ和ＨＦＪＶ＋ＤＩ均使ＰａＯ２明显升高，ＰａＣＯ２无明显变化（Ｐ＞０．０５），ＨＦＪＶ＋ＤＩ的氧释放指数（ＤＯ２Ｉ）明显高于ＣＭＶ组（Ｐ＞０．０５），心脏指数（ＣＩ）在ＣＭＶ组及ＨＦＪＶ＋ＤＩ组均明显减低（Ｐ＜０．０５）。提示：ＨＦＪＶ＋ＤＩ时ＰａＯ２的提高大于ＣＩ下降所致的不利影响，在改善组织缺氧方面明显优于ＣＭＶ时加用ＰＥＥＰ     

人工合成高密度脂蛋白样颗粒测定血清胆固醇酯转运蛋白活性

目的建立血清胆固醇酯转运蛋白活性测定方法。方法用１４Ｃ标记的胆固醇酯合成高密度脂蛋白（ＨＤＬ）样颗粒作为胆固醇酯的供体，以低密度脂蛋白为受体测定血清中胆固醇酯转运蛋白（ＣＥＴＰ）活性，并对４０例健康人、４５例冠心病（ＣＨＤ）、２６例脑卒中患者血清ＣＥＴＰ活性进行分析。结果　该方法线性范围为０～３０％；高（２６％）、低（６．８％）活性批内变异系数（ＣＶ）分别为６．０％、７．５％，批间ＣＶ分别为１１．５％和１２．３％；４５例ＣＨＤ患者血清ＣＥＴＰ活性（ｘ±ｓ）为１７．６％±５．４％，２６例脑卒中患者为１５．２％±３．８％，均明显高于健康对照（１２．７％±３．９％）（Ｐ＜０．０１）。结论该法简便快速、精密度较高，为临床及科研工作中测定ＣＥＴＰ活性提供了一种有效的方法。     

紫热线照射充氧自血中输对冠心病患者血清脂蛋白及载体蛋白的 …

目的：探讨紫外线照射充氧自血回输（ＵＢＩＯ）对血清总胆固醇（Ｔｃｈ）、甘油三酯（ＴＧ）、高密度脂蛋白胆固醇（ＨＤＬ－Ｃ）及其亚组分Ⅱ（ＨＤＬ２－Ｃ）、亚组分Ⅲ（ＨＤＬ３－Ｃ）、低密度脂蛋白胆固醇（ＬＤＬ－Ｃ）、载体蛋白（Ａｐｏ）Ａ１、Ａ２、ｂ１００、Ｃ２、Ｃ３的影响．方法：将冠心病高血脂患者分成两组，对照且２７例，给予硝酸酯类和维生素类药物，ＵＢＩＯ组３２中用光量子疗法。两组患者治疗期间停用其他影     

Endpoint colorimetric method for assaying total cholesterol in serum with cholesterol dehydrogenase

BACKGROUND: Various methods are available to measure serum cholesterol concentrations. Of these, the cholesterol ester hydrolase (CEH)-cholesterol oxidase-peroxidase chromogenic method is widely used. However, this method has the disadvantage of interference by reducing substances. We developed and evaluated an endpoint assay for serum cholesterol, based on a CEH-cholesterol dehydrogenase (CDH)-ultraviolet method. METHODS: Cholesterol esters are first hydrolyzed to free cholesterol by CEH. The free cholesterol is then reduced by CDH to cholest-4-ene-3-one with the simultaneous production of beta-NADH from beta-NAD(+). At equilibrium, the CDH reaction gives incomplete conversion of cholesterol to cholest-4-ene-3-one. To overcome this disadvantage, we added hydrazine monohydrate to the reaction mixture to remove cholest-4-ene-3-one, which allowed the reaction to proceed to completion and gave stoichiometric production of beta-NADH from the reaction of beta-NAD(+) with cholesterol. RESULTS: We tested whether the amount of cholesterol added was equivalent to the absorbance change of NADH at 340 nm with six aqueous samples. Recoveries were 97.1-100.3%. The reaction was linear up to 20.28 mmol/L. The mean within-day (n = 20) and between-day (n = 10) imprecision (CV) was 0. 29-0.43% and 0.22-0.61%, respectively. No interference by bilirubin, hemoglobin, ascorbic acid, and other reducing agents was observed. The equation obtained in comparison with the modified Abell-Levy-Brodie-Kendall method was: y = 0.992x - 0.0058 mmol/L; r = 0.997; S(y|x) = 0.117 mmol/L; n = 50. CONCLUSION: This method is an accurate, reliable method for serum cholesterol analysis and is amenable to automation.     

高效液相色谱测定血清高密度脂蛋白胆固醇分数和摩尔酯化速率

目的 建立一种高效液相色谱(HPLC)测定血清高密度脂蛋白胆固醇分数和摩尔酯化速率(FERHDL和MERHDDL)的方法.方法 用5,5'二硫代-2-硝基苯甲酸(DTNB)抑制全血中的卵磷脂胆固醇酰基转移酶(LCAT)活性,分离血清,制备HDL;HDL分别在含和不含2-巯基乙醇(ME)的条件下37℃温育1 h,HPLC法测定HDL游离胆固醇,计算FERHDL和MERHDL.结果 DTNB可以有效抑制全血中的LCAT活性,使游离胆固醇稳定在初始水平;ME可有效解除DTNB对LCAT的抑制作用;测定血清FERHDL和MERHDL的总变异系数分别为1.59%～3.74%和1.64%～2.88%;70名健康志愿者FERHDL.均值为18.7%/h(标准差7.2%/h),中位数16.1%/h;MERHDL均值42.7 μmol·L-1·h-1(标准差11.8 μmol·L-1·h-1),中位数41.6 μmol·L-1·h-1;FERHDL和MERHDL与多种心血管病危险因素显著相关.结论 本研究建立了血清FERHDL和MERHDL准确测定的方法,方法安全、简便、精密,将为进一步研究和应用FERHDL和MERHDL打下基础.     

The activity of cholesteryl ester transfer protein is decreased in hypothyroidism: a possible contribution to alterations in high-density lipoproteins

The activity of cholesteryl ester transfer protein is instrumental in the distribution of cholesteryl ester between lipoproteins in plasma. We measured the activity of cholesteryl ester transfer protein in plasma, designated cholesteryl ester transfer activity, as the rate of cholesteryl ester transfer between exogenous radiolabelled low-density and high-density lipoproteins. The effect of hypothyroidism on cholesteryl ester transfer activity was investigated in 13 athyreotic patients who were studied in the hypothyroid condition and in the euthyroid state, after they had received triiodothyronine supplementation for 33 to 67 days. During hypothyroidism plasma total cholesterol, very-low- plus low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, plasma triacylglycerol, apolipoprotein A1 and B were significantly higher than in the euthyroid state. Cholesteryl ester transfer activity was 15% lower during hypothyroidism (P less than 0.02), and an effect of treatment duration was observed. The changes in high-density lipoprotein total cholesterol (P less than 0.02), free cholesterol (P less than 0.001), triacylglycerol (P less than 0.05) and the free cholesterol/cholesteryl ester molar ratio in high-density lipoproteins (P less than 0.01) were inversely-related to the changes in cholesteryl ester transfer activity. We concluded that thyroid hormone is involved in the regulation of cholesteryl ester transfer protein activity, and that cholesteryl ester transfer protein activity may play a role in the alterations in high-density lipoprotein lipids observed in hypothyroidism.     

Studies on a polarographic determination method of serum cholesterol

In the present study, we tried to develop a polarographic determination method for cholesterol on the basis of a recent discovery of its enzymatic determination using cholesterol: oxygen oxidoreductase and cholesterol ester hydrolase. Dissolved oxygen in the reaction medium was consumed when free cholesterol was oxidised by cholesterol: oxygen oxidoreductase. The oxygen consumption was measured by an oxygen electrode to determine cholesterol quantitatively. There were two kinds of procedures, i.e. one is an “end-point method” in which the consumed oxygen at the end point of the reaction is measured, and the other a “rate method” in which the oxygen consumption rate at the initial point of the reaction is measured. We designed and equipped an apparatus to record both signals simultaneously.In the end-point method, there was a parallel relation between the consumed oxygen and the cholesterol concentration, and thus the unknown total cholesterol concentration or its components (free and esterified cholesterol) could be determined from the oxygen consumption by referring to the value of standard cholesterol solutions.In the rate method, the oxygen consumption rate at the initial phase was not proportional to the cholesterol concentration. Therefore, in order to accomplish proportionality, a competitive inhibitor (cholestenon) was used or the cholesterol concentration in the reaction medium was made low enough. In this method, cholesterol ester must be hydrolyzed and converted into free cholesterol in advance for total cholesterol determination. Cholesterol esterase was effective only in the presence of cholesterol: oxygen oxidoreductase. Hydrolysis also was tried with a lipoprotein lipase which possessed good activity to hydrolyze cholesterol ester.We examined 48 serum samples of patients to compare the newly developed method using lipoprotein lipase with the Zurkowski method. Fairly good correlation was obtained.     

Specificity assessment of immunoassay kits for determination of urinary free cortisol concentrations

BACKGROUND: In immunoassay kits for determination of urinary free cortisol (UFC) concentrations, the results vary markedly from kit to kit, so we compared in this study the reaction specificity among 4 commercially available immunoassay kits to determine the applicability of these assays in routine determination of UFC concentrations. METHOD: Using 4 commercially available kits, cross-reaction was investigated. In addition, urine samples were fractionated by HPLC to investigate endogenous immunoreactive cortisol responses. HPLC fractions were subjected to gas chromatography-mass spectrometry (GCMS) to identify substances causing inter-kit assay discrepancies. RESULTS: Among the 4 kits, cortisol Kit "TFB" (Immunotech; IOT-RIA method) showed the lowest cross-reaction (2.5%) for prednisolone. Furthermore, on HPLC, 87.8% of the reaction of the entire fraction was seen in the fractions corresponding to the elution position of standard cortisol with the IOT-RIA method; this was the highest percentage among the 4 kits. GCMS revealed that the substance that showed a cross-reaction with the other 3 kits was 5alpha-tetrahydrocortisol (5alpha-THF) glucuronide. CONCLUSIONS: The IOT-RIA method was found to be the most specific for UFC. The other 3 commercially available kits showed cross-reaction with a conjugate of 5alpha-THF, found to be one of the causes of inter-kit assay discrepancies.     

Macrophage-specific transgenic expression of cholesteryl ester hydrolase significantly reduces atherosclerosis and lesion necrosis in Ldlr mice

Accumulation of cholesteryl esters (CEs) in macrophage foam cells, central to atherosclerotic plaque formation, occurs as a result of imbalance between the cholesterol influx and efflux pathways. While the uptake, or influx, of modified lipoproteins is largely unregulated, extracellular acceptor-mediated free cholesterol (FC) efflux is rate limited by the intracellular hydrolysis of CE. We previously identified and cloned a neutral CE hydrolase (CEH) from human macrophages and demonstrated its role in cellular CE mobilization. In the present study, we examined the hypothesis that macrophage-specific overexpression of CEH in atherosclerosis-susceptible Ldlr(-/-) mice will result in reduction of diet-induced atherosclerosis. Transgenic mice overexpressing this CEH specifically in the macrophages (driven by scavenger receptor promoter/enhancer) were developed and crossed into the Ldlr(-/-) background (Ldlr(-/-)CEHTg mice). Macrophage-specific overexpression of CEH led to a significant reduction in the lesion area and cholesterol content of high-fat, high-cholesterol diet-induced atherosclerotic lesions. The lesions from Ldlr(-/-)CEHTg mice did not have increased FC, were less necrotic, and contained significantly higher numbers of viable macrophage foam cells. Higher CEH-mediated FC efflux resulted in enhanced flux of FC from macrophages to gall bladder bile and feces in vivo. These studies demonstrate that by enhancing cholesterol efflux and reverse cholesterol transport, macrophage-specific overexpression of CEH is antiatherogenic.     

Effects of serum storage on the determination of cholesterol

Cholesterol determined by 4 different enzymatic commercial kits and by the dry chemistry Reflotron system was higher in serum stored at 4 °C and at −20 °C than in fresh serum. The effects of storage seem to be temperature-dependent. In fact, cholesterol values significantly increased only after 2h of freezing. The prolongation of freezing up to 2 weeks was not followed by further significant changes. In serum stored at 4 °C the increase in cholesterol was slower than in frozen serum. Both free and esterified cholesterol underwent an increase after storage. When cholesterol was determined by a chemical method (sulfuric acid-ferric chloride) after extraction with ethyl acetate and ethanol, no difference was observed in fresh and stored serum. Cholesterol, triglycerides and apoproteins A-I and B underwent parallel changes after storage both in whole serum and fractionated lipoproteins. Our findings strongly suggest that in serum stored at positive or negative temperature there is an alteration of the lipoprotein molecules which allows an easier availability of cholesterol for the enzyme-substrate reaction than in fresh serum. Current enzymatic methods underestimate (about 10%) cholesterol when the analysis is performed on fresh serum.     

Analytical examination of oxidized free and esterified 7-ketocholesterol and related oxysterols in human plasma incubated with copper.

Oxygenated derivatives of cholesterol (oxysterols) have been demonstrated to possess a wide variety of biological properties and evaluated for their abilities to inhibit cholesterol biosynthesis. We investigated a method to analyze copper-catalyzed oxidation products of human plasma cholesterol. Free and esterified oxysterols produced were mainly 7-ketocholesterol, and small amounts of 7 beta-hydroxycholesterol and 5, 6 alpha-epoxy-cholesterol were also identified. Quantitatively, the sterol nucleus of ester was less susceptible to oxidation than that of the free form. This finding suggested that the cholesterol nucleus of ester form was more resistant against oxidative stress than free form. Additionally we demonstrated that the addition of probucol, a powerful antioxidant used clinically to lower blood cholesterol, inhibited this copper-catalyzed oxidation of cholesterol.     

超速离心-高效液相色谱测定血清高密度和低密度脂蛋白胆固醇

目的 建立一种新的预期用作参考方法的高密度脂蛋白胆固醇（HDLC）和低密度脂蛋白胆固醇（LDLC）准确测定方法。方法 血清与含2-琉基乙醇（ME）和脯氨酸的溴化钠溶液混合，使背景密度为1．063，超速离心分离高密度脂蛋白（HDL）；血清与含脯氨酸的溴化钠溶液混合，使背景密度为1.006，超速离心分离HDL和低密度脂蛋白（LDL）；用高效液相色谱测定两种脂蛋白组分胆固醇。结果 ME和脯氨酸可有效消除脂蛋白（a）对超速离心法分离HDL的影响；新方法测定HDLC和LDLC的总变异系数分别为0．96％～2、07％和0．65％～1．12％。结论 建立血清HDLC和LDLC准确测定方法，方法可靠、精密、简便，可望用作HDLC和LDLC测定参考方法。     

血清总胆固醇、总甘油、游离甘油和甘油三酯标准物质的研制

目的 研制与临床标本基质相似的血清总胆固醇(TC)、总甘油(TTG)、游离甘油(FG)和甘油三酯(TG)标准物质.方法 按国家标准物质技术规范的要求,制备4种血脂浓度的健康人新鲜混合血清,用酶法测定TC检测均匀性,用HPLC法检测稳定性并定值,评估不确定度.结果 4种血清均匀性检验数据方差分析P值分别为0.339、0.212、0.275、0.196(均＞0.05),说明均匀性良好;稳定性研究结果显示4种血清TC和TG在-20℃保存至少可稳定4年;4种血清的标准值和不确定度TC分别为(5.110±0.064)mmol/L、(4.761±0.062)mmol/L、(3.941±0.050)mmol/L和(3.158±0.041)mmol/L;TTG分别为(2.212±0.043)mmol/L、(1.679±0.033)mmol/L、(1.275±0.027)mmol/L和(1.067±0.023)mmol/L;FG分别为(0.142±0.005)mmol/L、(0.149±0.004)mmol/L、(0.146±0.003)mmol/L和(0.122±0.003)mmol/L;TG分别为(2.069±0.043)mmol/L、(1.530±0.033)mmol/L、(1.129±0.027)mmol/L和(0.945±0.023)mmol/L.结论 研制的血清总胆固醇、总甘油、游离甘油和甘油三酯标准物质均匀性和稳定性良好,定值可靠,已被国家质量监督检验检疫总局发布为国家一级标准物质(GBW 09145、GBW 09146、GBW 09147、GBW 09148).