Estimation of LDL cholesterol based on the Friedewald formula and on apo B levels

OBJECTIVES: The plasma apolipoprotein B (apo B) concentrations have been considered to be a more accurate representation of atherogenic particles and it has been proposed that the formula LDL-C (mmol/L) = 0.41TC - 0.32TG + 1.70apo B - 0.27 is reliable for the estimation of LDL-C (Clin Chem 1997; 43: 808-15). We undertook the present study to investigate the reliability of this formula in a large number of hyperlipidemic patients. DESIGN AND METHODS: 1) The Friedewald formula (LDL-F) and the apo B-based formula (LDL-B) were compared with the beta-quantification reference procedure in 130 individuals with a wide range of total cholesterol (TC) and triglyceride (TG) levels, and 2) the LDL-C levels obtained by the Friedewald formula were compared with those calculated by the apo B-based formula in 1010 individuals attending our outpatient lipid clinic. RESULTS: The LDL-F and the LDL-B formulae for LDL-C estimation were found to be in good agreement with the beta-quantification (r = 0.96 and 0.97, respectively). The bias of each method plotted as a function of TG (up to 4.52 mmol/L) was found positive for the LDL-F, whereas the LDL-B was independent of the concentrations of TG. When a large number of individuals were examined, a good correlation between the two equations was found (n = 1010, r = 0.98). The difference between the two methods was not correlated with serum TG levels. However, it was correlated to serum TC, and apo B levels. CONCLUSIONS: The LDL-B formula is a more reliable and accurate method than the LDL-F formula, especially at TG levels >2.26 mmol/L, although it underestimates LDL-C concentrations. Furthermore, this equation can be used in hypertriglyceridemic patients (TG >4.52 mmol/L) in whom the Friedewald equation is inaccurate.     

Effects of total cholesterol and triglyceride on the percentage difference between the low-density lipoprotein cholesterol concentration measured directly and calculated using the Friedewald formula.

BACKGROUND: We elucidate how the triglyceride (TG) and total cholesterol (TC) concentrations affect the percentage difference (%DeltaLDL) between the low-density lipoprotein cholesterol (LDL-C) concentration evaluated by direct measurement (DLDL-C) and calculated using the Friedewald formula (FLDL-C), under conditions allowing the calculation. METHODS: Serum concentrations of TC, TG, high-density lipoprotein cholesterol (HDL-C), and DLDL-C were measured and the FLDL-C and %DeltaLDL were calculated for 38,243 Koreans who had TG values <4.52 mmol/L. The DLDL-C was measured using the homogeneous Kyowa Medex assay (Kyowa, Tokyo, Japan). The %DeltaLDL was calculated using the equation: [(FLDL-C-DLDL-C)/DLDL-C]x100. RESULTS: The mean %DeltaLDL-C was -9.1+/-6.4%. The %DeltaLDL differed by more than +/-5% in 75.4% of the subjects, and the FLDL-C was lower than the DLDL-C in 96.3%. The mean %DeltaLDL-C for the group with the highest TG and lowest TC was 11.8-fold that for the group with the lowest TG and highest TC. CONCLUSIONS: Under conditions satisfying the requirements of the Friedewald formula, the DLDL-C and FLDL-C differed significantly over the concentration ranges of both TC and TG. In an evaluation of patients with hyperlipidemia, the Friedewald calculation may underestimate the risk for coronary heart disease.     

Comparing a novel equation for calculating low-density lipoprotein cholesterol with the Friedewald equation: A VOYAGER analysis

Treating elevated low-density lipoprotein cholesterol (LDL-C) to risk-stratified target levels is recommended in several guidelines. Thus, accurate estimation of LDL-C is required. LDL-C is typically calculated using the Friedewald equation: (total cholesterol) – (non-high-density lipoprotein cholesterol [non-HDL-C]) – (triglycerides [TGs]/5). As the equation uses a fixed value equal to 5 as a divisor for TGs, it does not account for inter-individual variability, often resulting in underestimation of risk and potentially undertreatment. It is specifically inapplicable in patients with fasting triglycerides ≥400 mg/dL. A novel method of LDL-C calculation was derived and validated by Martin et al.: (non-HDL-C) – (triglycerides/adjustable factor). This equation uses an adjustable factor, the median TG:very-low-density lipoprotein cholesterol ratio in strata defined by levels of TG and non-HDLC, as divisor for TGs, and the adjustable factor ranging from 3 to 12 has been shown to provide more accurate estimates of LDL-C compared with the Friedewald equation using a direct assay as the gold standard.We used 70,209 baseline and on-treatment lipid values from the VOYAGER meta-analysis database to determine the difference in calculated LDL-C values using the Friedewald and novel equations. In patients with TGs <400 mg/dL, LDL-C values calculated using the novel equation were plotted against those calculated using the Friedewald equation. The novel equation generally resulted in LDL-C values greater than the Friedewald calculation, with differences increasing with decreasing LDL-C levels; 23% of individuals who reached a LDL-C target of 70 mg/dL with the Friedewald equation did not achieve this target when the novel equation was used to calculate LDL-C; these figures were 8% and 2% for <100 mg/dL and < 130 mg/dL targets, respectively. In patients with triglycerides ≥400 mg/dL, in whom the Friedewald equation is not valid, lipid values calculated using the novel equation were compared with those obtained by β-quantification. Values calculated with the novel equation did not appear to be closely related with those calculated by β-quantification in these patients. In conclusion, the novel equation provides a higher estimation of exact LDL-C values than the Friedewald equation, particularly in patients with low LDL-C levels, which may result in undertreatment of some patients whose LDL-C was calculated using the Friedewald method. However, neither may be suitable for patients with TG ≥400 mg/dL.     

Evaluation of five methods for determining low-density lipoprotein cholesterol (LDL-C) in hemodialysis patients(1)

Objectives: Current recommendations for the management of dyslipidemia are largely based on the concentration of LDL-C. Most clinical laboratories estimate the concentration of LDL-C by the recommended routine method, the equation of Friedewald, in specimens from fasting subjects and with TG concentrations < 4.52 mmol/L. Because of the limitations of the Friedewald calculation, direct methods for an accurate quantification of LDL-C are needed.

Design and Methods: In the present study we evaluated the accuracy of the following 5 different procedures for LDL-C in 98 patients on hemodialysis: the Friedewald equation, where LDL-C is calculated from HDL-C, measured either by the precipitation procedure with dextran sulfate-Mg²⁺ (Method 1), or by a direct HDL-C assay (Method 2), the Direct LDL™ assay (Method 3), the homogeneous N-geneous™ LDL assay (Method 4) and the calculated LDL-C values deriving from the ApoB based equation: 0.41TC - 0.32TG + 1.70ApoB - 0.27, (Clin Chem 1997;43:808–815) (Method 5).

Results: All five LDL-C methods were found to be in good agreement with ultracentrifugation/dextran sulfate-Mg²⁺ precipitation with the coefficients of correlation of the assays to ranging between 0.93–0.95. However, significant differences in the mean values and biases vs. the reference method were observed. The Friedewald equation and the Direct assay were less affected by high LDL-C levels, and they presented higher sensitivity and higher negative predictive value. The N-geneous assay and the ApoB derived calculation were less affected by high triglyceride levels, and they presented higher specificity and higher positive predictive value. At the diagnostic LDL-C level of 3.37 mmol/L, both Friedewald calculations correctly classified 82/92 patients; Direct assay 86/98; N-geneous assay 88/98; and ApoB derived calculation 88/98. At the diagnostic LDL-C level of 2.98 mmol/L, Friedewald calculations (Method 1 and Method 2) correctly classified 82/92 and 81/92 patients, respectively; Direct assay (LDL-3) 87/98; N-geneous assay (LDL-4) 91/98; and ApoB derived calculation (LDL-5) 91/98.

Conclusions: Among hemodialysis patients, who commonly present “average” LDL-C concentrations and high TG levels, the N-geneous assay and the apoB derived calculation seem to yield more acceptable results for the estimation of LDL-C.     

血脂相关指标测定方法的比较研究

目的对比研究肝素抗凝、方法选择等因素对血脂指标测定值的影响。方法⑴随机抽样体检者130人,采血后离心分离血浆(肝素抗凝)和血清。按试剂盒方法(直接法),分别测定两组的甘油三酯(TG),总胆固醇(TC),低密度脂蛋白胆固醇(LDL-C),高密度脂蛋白胆固醇(HDL-C),载脂蛋白A(ApoA),载脂蛋白B(ApoB)等指标,并对两组差异进行统计性分析。⑵随机抽样心血管患者320人,按直接法测定血清TG,TC,LDL-C,HDLC,ApoA,ApoB等指标。将患者分为TG<1.5mmol/L(n=170),1.5≤TG<2.5mmol/L(n=96),2.5≤TG<3.5mmol/L(n=29),3.5≤TG<4.5mmol/L(n=10),TG≥4.5mmol/L(n=15)等5组,根据Friedewald、Planella公式,分别计算两组的LDL-C值,并与直接法比较统计学差异。结果⑴血浆、血清测定指标中,TG分别为2.63±2.03mmol/L,2.56±2.06mmol/L,P<0.05;TC,LDL-C,HDLC,ApoA,ApoB相互比较,P>0.05。⑵Friedewald公式所得的5组LDL-C值与直接法比较,P<0.01;Planella公式所得的5组LDL-C值与直接法比较,P>0.1,P<0.01,P<0.002,P<0.01,P>0.05。结论直接法测定TC,LDL-C,HDLC,ApoA,ApoB时,可用肝素抗凝的血浆替代血清,但直接法测定TG及公式法计算LDL-C时不能替代;Friedewald、Planella公式计算LDL-C误差较大,TG<1.5mmol/L时可采用Planella公式,TG>1.5mmol/L时建议采用直接法。     

Validation of the Friedewald formula for the determination of low-density lipoprotein cholesterol compared with beta-quantification in a large population

Lipoprotein data from 9477 subjects, covering a wide range of total plasma cholesterol levels, were used to examine the validity of the Friedewald formula for estimating plasma concentrations of low-density lipoprotein cholesterol (LDL-C) using high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) concentrations. Values of LDL-C obtained from the Friedewald formula were compared with values of LDL-C derived from preparative ultracentrifugation used as a reference method. We found that the bias associated with the Friedewald formula was not related to plasma LDL-C levels and was smaller than −4.0% even for plasma LDL-C values <3.0 mmol/l. Moreover, in the subgroup of individuals with plasma TG levels ≤4.5 mmol/l, the Friedewald formula underestimated LDL-C levels with a bias between −3.1% and −1.9% according to TG quartiles. Interestingly, the Friedewald formula showed no significant bias in patients with plasma TG levels between 4.51 and 8.82 mmol/l, suggesting that the calculated LDL-C are reliable and could be clinically useful in patients with plasma TG levels higher than 4.5 mmol/l which is the reference cut-point value used by most clinical laboratories. Finally, multiple regression analyses showed that the very low-density lipoprotein cholesterol (VLDL-C)/TG ratio represented nearly 63% (P < 0.0001) of the variance of the bias associated with the Friedewald formula. We concluded that the Friedewald formula may be reliable at low LDL-C levels and at TG levels up to 9 mmol/l but may be used with caution when the VLDL-C/TG ratio is high as observed in patients with type III dysbetalipoproteinemia.     

脑梗死患者中的血清总胆固醇、低密度脂蛋白及非高密度脂蛋白胆固醇的含量分析

目的:探讨总胆固醇(TC)、低密度脂蛋白(LDL-C)及非高密度脂蛋白胆固醇(non-HDL-C)与脑梗死关系,为预防和临床治疗提供参考。方法:153例脑梗死患者分为单纯脑梗死组(57例)、合并糖尿病组(43例)、合并高血压组(53例),另设67例健康体检者为对照组,各组均测定血清三酰甘油(TG),TC和HDL-C,同时根据Friedewald公式计算出LDL-C,按Frost法计算出non-HDL-C含量,数据输入计算机进行分析。结果:脑梗死各组血清TC、LDL-C及non-HDL-C含量均高于对照组,有显著差异(P<0.01);脑梗死各组间比较,LDL-C无显著差异,但糖尿病组TC及non-HDL-C含量高于单纯脑梗死组和合并高血压组,有显著差异(P<0.01)。结论:TC及non-HDL-C与脑梗死的发生有关,应重视合并糖尿病的脑梗死患者血清non-HDL-C含量。     

Estimation of VLDL cholesterol in hyperlipidemia

Lipoprotein data from 10947 fasting blood samples drawn between 1968 and 1982 in the Molecular Disease Branch at the National Institutes of Health were used to test the generalizability of estimating very low density lipoprotein cholesterol (VLDL-C) from plasma triglyceride (TG). Patient samples with total cholesterol levels over 500 mg/l and triglyceride values in the 0-100 000 mg/1 range were included in this study. A previously defined linear relationship VLDL-C = 0.20 (TG) was observed in the past by Friedewald and collaborators, allowing estimation of low density lipoprotein cholesterol (LDL-C) without ultracentrifugation for TG values up to 4 000 mg/1. The results from this report extend the use of the Friedewald relationship to higher TG levels, and to various dyslipidemic states. As the VLDL-C estimates become increasingly imprecise for TG values greater than 10 000 mg/l, caution should be exercised using the estimate in the higher TG ranges. Comparisons with an alternative equation VLDL-C = 0.166 (TG) showed equal or improved accuracy with this estimation procedure, particularly at high TG levels.     

Direct measurement of LDL-C in children: performance of two surfactant-based methods in a general pediatric population

OBJECTIVES: Several pediatric advisory groups have recommended selective screening for dyslipidemia in children. Low-density lipoprotein cholesterol (LDL-C) is measured clinically with the Friedewald calculation in fasting samples. Nonfasting measurement of LDL-C would be clinically useful in children. DESIGN AND METHODS: In the present study, we examine the performance of two surfactant-based direct LDL-C assays in paired samples, fasting and nonfasting, from 100 children. RESULTS: LDL-C in the fasting state was significantly lower with the Friedewald estimation: 2.43 +/- 0. 61 mmol/L, N-geneous (Genzyme Corp.) direct LDL-C: 2.30 +/- 0.59 mmol/L, and Roche (Roche Diagnostics) direct LDL-C: 2.32 +/- 0.57 mmol/L than with ultracentrifugation-dextran-sulfate-Mg(2+) precipitation (UC-DS): 2.47 +/- 0.64 mmol/L. Moreover, there was increased negative bias using nonfasting samples with N-geneous: 2. 25 +/- 0.56 mmol/L and Roche: 2.26 +/- 0.56 mmol/L compared with fasting UC-DS. Correlation with US-DS was highest for Friedewald (r = 0.974) and fasting N-geneous (r = 0.973), and lowest with nonfasting N-geneous (r = 0.849) and Roche in fasting (r = 0.891) and nonfasting samples (r = 0.747). The sensitivity at LDL-C concentration of 2.85 mmol/L for the two direct methods when either fasting or nonfasting samples were used, was lower than that obtained with Friedewald. CONCLUSION: Overall, these direct LDL-C assays demonstrated limited utility in screening children but may be useful in the management of lipid disorders.     

Influence of intermediate-density lipoproteins on the accuracy of the Friedewald formula

Values of low-density lipoprotein (LDL) cholesterol (C) according to the Friedewald formula (Clin Chem 1972;18:499-502) were compared with those obtained by lipoprotein fractionation in 98 healthy subjects (control group), 135 specimens from patients with peripheral vascular and cerebrovascular disease (atherosclerotic group), and 45 with chronic renal failure on hemodialysis (CRF group). All had concentrations of total cholesterol between 3.23 and 7.76 mmol/L (1.25-3.00 g/L) and triglycerides less than 3.39 mmol/L (less than 3.00 g/L). The percentage error of calculated LDL-C was 4% in controls with a cholesterol/triglycerides (C/TG) ratio for very-low-density lipoprotein (VLDL) of 0.20, but greater than 60% in those with a (C/TG)VLDL ratio of 0.40. The percentage of error in sera of patients with atherosclerosis and chronic renal failure was higher than in controls with a similar mean (C/TG)VLDL ratio. The percentage of error of calculated LDL-C increases progressively with the increase in the C/TG intermediate-density lipoprotein (IDL) ratio, both in controls and in the atherosclerotic and CRF groups. Similar findings are observed when the mean percentage of error of measured LDL-C is evaluated. The percentage of error from calculated LDL-C in the atherosclerotic and CRF groups is significantly lower than that obtained by comparison of LDL-C separated by ultracentrifugation when the "broad cut" LDL (IDL plus LDL, both by ultracentrifugation) was used. The high percentage of errors found in the groups of patients studied underlines the need for caution when assessing the reliability of the Friedewald formula, particularly in cases in which disturbances in IDL composition are suspected.     

甲状腺功能亢进症危象患者脂代谢的特点及意义

目的:探讨甲状腺功能亢进症危象(简称甲亢危象)患者血脂代谢紊乱的特点及临床意义。方法:检测42例甲亢危象患者(甲亢危象组)、50例甲亢患者(甲亢组)和50例正常健康体检者(对照组)的身高、体重并计算体重指数(BMI),并抽血测定甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、甲状腺功能(FT3、FT4)。结果:(1)甲亢组与对照组比较,HDL-C、BMI略有下降(P>0.05),TC、TG和LDL-C均有下降(P<0.05)。甲亢危象组与对照组比较,HDL-C、BMI下降(P<0.05),TC、TG和LDL-C均有明显下降(P<0.01)。甲亢危象组与甲亢组比较HDL-C下降更明显(P<0.01)。其余各指标差异无统计学意义。(2)甲亢危象组中<18岁患者与对照组比较,TG、HDL-C和BMI略有下降(P>0.05),TC和LDL-C均有下降(P<0.01);18～45岁患者与对照组比较,BMI略有下降(P>0.05),HDL-C、TG均有下降(P<0.05),TC和LDL-C均有明显下降(P<0.01);46～59岁患者与对照组比较,TG、HDL-C和BMI稍有改变(P>0.05),TC和LDL-C均有下降(P<0.05);≥60岁患者与对照组比较,TC、TG、HDL-C和BMI差异无统计学意义(P>0.05),LDL-C下降(P<0.05)。且甲亢危象组中≥60岁患者与18～45岁患者比较,TC和HDL-C均上升(P<0.05);其余不同年龄组间各相关指标差异无统计学意义(P>0.05)。(3)甲亢危象患者TC、TG与FT3呈负相关(r=-0.573,P<0.01;r=-0.475,P<0.01);HDL-C、LDL-C、BMI与FT3无相关。(4)甲亢危象患者TC与FT4呈负相关(r=-0.738,P<0.01);TG、HDL-C、LDL-C、BMI与FT4无相关。结论:甲亢危象患者存在明显的血脂代谢紊乱,临床救治过程中应兼顾血脂代谢的变化。     

中重度牙周炎合并银屑病与代谢综合征各组分的关系

目的 探讨中重度牙周炎合并银屑病与代谢综合征(MS)各组分的相关性.方法 选取中重度牙周炎患者50例(中重度牙周炎组)、银屑病患者50例(银屑病组)、中重度牙周炎合并银屑病患者50例(中重度牙周炎合并银屑病组),以健康体检者50名作为正常对照组.检测所有对象的血压、糖化血红蛋白(HbA1c)、血糖(Glu)、三酰甘油(...     

Calculated low density lipoprotein cholesterol levels frequently underestimate directly measured low density lipoprotein cholesterol determinations in patients with serum triglyceride levels < or =4.52 mmol/l: an analysis comparing the LipiDirect magnetic LDL assay with the Friedewald calculation

BACKGROUND: Increased low density lipoprotein cholesterol (LDL-C) is an established risk factor for the development of coronary artery disease (CAD). Recent guidelines detail specific LDL-C cutpoints for therapeutic goals. In practice, LDL-C is usually derived from the Friedewald formula (FF). This calculation is known to be inaccurate with serum triglyceride (TG) concentrations >4.52 mmol/l, however, its accuracy among relatively healthy patient cohorts with TG concentrations < or =4.52 mmol/l is less well studied. METHODS: We studied 661 ambulatory adults with TG concentrations < or =4.52 mmol/l and no overt CAD. Fasting venous lipid panels were obtained. LDL-C was calculated from the FF and also directly measured with the LipiDirect Magnetic LDL assay. Linear regression and paired t-test analyses were performed. RESULTS: Calculated and directly measured LDL-C concentrations were significantly different (4.26+/-0.88 vs. 4.83+/-1.06 mmol/l respectively, p<0.0001). In 93% of measurements directly measured LDL-C exceeded calculated LDL-C. Although calculated and directly measured LDL-C concentrations were related (R=0.90), the discrepancy between them increased linearly with increasing TG concentrations (R=0.67) and clinically important differences existed at normal or slightly increased TG concentrations. Concordant results for NCEP ATP-III risk categories were present for only 48.1% of samples. CONCLUSIONS: Significant differences between calculated and directly measured LDL-C using the LipiDirect Magnetic LDL assay exist in healthy subjects with TG < or =4.52 mmol/l. These differences are linearly related to TG concentrations and occur frequently at relatively low TG concentrations.     

博心通胶囊对脑梗死患者颈动脉不稳定粥样斑块影响的临床观察

目的:观察博心通胶囊对脑梗死患者颈动脉不稳定粥样斑块的作用。方法:符合纳入标准的脑梗死患者130例随机分为2组,各65例;在常规治疗基础上,对照组口服普罗布考片,博心通组口服博心通胶囊,治疗12个月。分别于治疗前及治疗6、12月,检测患者血脂、颈动脉不稳定粥样硬化斑块的数目、大小以及不良事件情况。结果:治疗6个月后,2组甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)较治疗前均降低(P<0.05),博心通组TG、TC、LDL-C低于对照组(P<0.05);治疗12个月时,2组TG、TC、LDL-C较治疗前均降低(P<0.05),但2组间差异无统计学意义;2组高密度脂蛋白胆固醇(HDL-C)治疗前后水平改变差异无统计学意义;博心通组斑块的"有效"及"稳定"率高于对照组(P<0.05);博心通组治疗有效率及稳定率均显著高于对照组(P<0.01)。2组均无明显不良事件发生。结论:博心通胶囊能有助于降低脑梗死患者血脂、稳定斑块、减少缺血事件发生,且安全。     

Impact of the Martin/Hopkins modified equation for estimating LDL-C on lipid target attainment in a high risk patient population

ObjectiveTo evaluate the Martin/Hopkins equation for estimating LDL-C as target in a population composed of high cardiac risk patients.MethodsLipid profile data from patients with TG ≤ 4.52 mmol/L (<400 mg/dl) were used. The high cardiac risk group (N 4150) consisted of patients over 40 years of age that had an A1C level of 6.5% or above and patients with a history of atherosclerotic cardiovascular disease (ASCVD). Comparisons were made between the Martin/Hopkins formula (MH-LDL-C), the Friedewald formula (F-LDL-C), Non-HDL-C and ApoB.ResultsHigher LDL-C values (0.15 mmol/L or 7.3%) were obtained using MH-LDL-C compared to the F-LDL-C. The % within target (%WT) values for F-LDL-C, MH-LDL-C, Non-HDL-C and ApoB were similar when TG levels were ≤ 1.5 mmol/L with a high degree of concordance as measured by the kappa statistic. When compared to F-LDL-C, Non-HDL-C and ApoB showed a profound decrease in the WT value as TG levels increased from normal (67.7%) to intermediate (39.1%) and high levels (20.8%). MH-LDL-C showed an attenuated decrease in the WT value as TG increased from normal (61.4%) intermediate (43.4%) and high levels (32.7%). Concordance with the alternate target parameters was higher for MH-LDL-C than for F-LDL-C when triglycerides levels were increased.ConclusionThe Martin/Hopkins modified equation for estimating LDL-C is a significant improvement on the decade’s old Friedewald formula; however it remains an imperfect tool to estimate the atherogenic load in patients with high TG levels.     

血脂代谢紊乱与中青年脑梗死危险因素的相关性分析

目的探讨血脂与中青年人脑梗死的关系. 方法检测了 111例中青年人脑梗死患者及 80例对照者的三酰甘油、总胆固醇、高密度脂蛋白胆固醇 (High density lipoprotein cholesterol, HDL-C)、低密度脂蛋白胆固醇 (Low density lipoprotein cholesterol,LDL-C)、载脂蛋白 A-I(apolipoproteinA-I,ApoA-I)、载脂蛋白 B100(apolipoprotein B100, ApoB100)和脂蛋白 (a)血清含量. 结果脑梗死组三酰甘油 [(1.92± 1.33)mmol/L],总胆固醇 [(5.21± 1.08)mmol/L],LDL-C[(3.13± 0.96)]mmol/L,ApoB100[(1.10± 0.29)g/L]及脂蛋白 (a)[(0.23± 0.18)]g/L水平高于对照组 (t=2.523～ 3.796,P< 0.05),总胆固醇与年龄呈正相关 [青年 (4.96± 1.14)mmol/L,中年 (5.27± 1.06)mmol/L], HDL-C与年龄呈负相关 [青年 (1.39± 0.43)mmol/L,中年 (1.26± 0.35)mmol/L].亚组分析发现青年人脑梗死亚组的脂蛋白 (a)水平和中年人脑梗死亚组的三酰甘油、总胆固醇、 LDL-C、 ApoB100及脂蛋白 (a)水平均显著高于相应的对照组 (t=2.571～ 4.107,P< 0.05);皮层支动脉闭塞亚组脂蛋白 (a)水平显著高于穿通支动脉闭塞亚组 (t=5.414,P< 0.01);首发脑梗死亚组与复发脑梗死亚组之间的血脂水平无显著差异. 结论血脂代谢紊乱是中青年人脑梗死的危险因素.     

短期辛伐他汀40 mg治疗不稳定型心绞痛对血浆高敏C-反应蛋白水平的影响

目的探讨使用大剂量(40 mg/d)和常规剂量(20 mg/d)辛伐他汀治疗2周后不稳定型心绞痛(UAP)患者血浆高敏C反应蛋白(hs-CRP)浓度的变化,分析短期强化降脂治疗对hs-CRP水平的影响。方法选取UAP患者76例,随机分为常规降脂组和强化降脂组,分别接受辛伐他汀20 mg/d和40 mg/d治疗,测定治疗前及治疗后1周、2周血脂[总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、甘油三酯(TG)]和hs-CRP水平。结果常规降脂组和强化降脂组治疗2周后TG、和HDL-C变化不明显,TC和LDL-C均呈下降趋势(TC:F=44.88,P<0.0001;LDL-C:F=32.92,P<0.0001),强化降脂组下降更明显常规降脂和强化降脂治疗后hs-CRP水平呈下降趋势(F=4.515,P=0.044),强化降脂组治疗2周后hs-CRP下降更明显。相关性分析显示治疗后血浆hs-CRP浓度的变化与同期血脂(TC、LDL-C、HDL-C、TG)水平的变化无显著相关性。结论短期辛伐他汀治疗可以明显降低TC和LDL-C,辛伐他汀40 mg/d强化降脂治疗效果更显著;强化降脂治疗可以使hs-CRP水平显著下降,但与血脂下降并不相关。     

A rapid micro-scale procedure for determination of the total lipid profile

We describe a one-day micro-scale procedure for determining the total lipid profile. Only 0.55 mL of plasma is needed for complete quantification of total cholesterol (TC), triglyceride (TG), and all lipoproteins. After precipitation with dextran sulfate and magnesium, the high-density lipoprotein (HDL) fraction was separated by centrifugation in an Eppendorf microcentrifuge. Very-low-density lipoprotein (VLDL) was separated from low-density lipoprotein (LDL) plus HDL in a Beckman TL 100 ultracentrifuge. TC, TG, and cholesterol in different lipoprotein fractions were measured enzymatically in a Baker "Encore II" automated analyzer. CVs, both within-day and day-to-day, were less than 3% for TG and TC, and less than 5% for HDL-C determinations. CVs for LDL-C and VLDL-C were less than 7.5% and 15%, respectively. Results by our micromethods (n = 66) agreed well with those by the conventional methods used at the Northwest Lipid Research Center, which are standardized against the Reference Methods of the Centers for Disease Control. Coefficients of correlation between the two methods were 0.98 for TC, 1.0 for TG, 0.98 for HDL-C, 0.94 for LDL-C, and 0.96 for VLDL-C. Results of electrophoresis on agarose gel and radioactivity-recovery studies indicate that our micro-centrifugation and slicing procedures result in clean separation of VLDL from other lipoproteins.     

Serum total cholesterol, HDL-C and LDL-C concentrations significantly correlate with the radiological extent of disease and the degree of smear positivity in patients with pulmonary tuberculosis

BACKGROUND: Low serum total cholesterol (TC) concentrations in patients with pulmonary tuberculosis (PTB) have been demonstrated. It was shown that a cholesterol-rich diet might accelerate the sterilization rate of sputum cultures in PTB patients. It is known that smear positivity might be related to the radiological extent of disease (RED) in PTB patients. OBJECTIVE: We hypothesized that there might be a relationship between initial serum TC concentrations; the degree of RED (DRED) and the degree of smear positivity (DSP) in PTB patients. METHOD: Eighty-three PTB patients and 39 healthy controls were included in the study. Serum TC, TG, HDL-C, VLDL-C and LDL-C concentrations were determined in all subjects. PTB patients were classified for their chest X-ray findings as minimal/mild, moderate and advanced. Correlations between serum lipid concentrations, DRED and DSP (0, 1+, 2+, 3+, 4+) were investigated. PTB patients and controls were also compared for serum lipid concentrations. RESULTS: Significant differences between PTB patients and controls were detected for serum TC, HDL-C and LDL-C concentrations. On stepwise logistic regression analysis, DRED was found as one of the significant independent predictors of serum TC levels. We also found significant correlations between DRED and serum HDL-C concentrations (r=-0.60, p=0.0001) and between DRED and serum LDL-C concentrations (r=-0.28, p=0.011). There were also significant correlations between DSP and serum lipid concentrations. CONCLUSION: Our study suggests that serum TC, HDL-C and LDL-C concentrations are generally lower in patients with PTB than those in healthy controls. In addition, changes in these parameters might be related to DRED and DSP in PTB patients.     

超敏C-反应蛋白在2型糖尿病并发动脉粥样硬化中的研究

目的 探讨血清超敏C-反应蛋白(Hs-CRP)、胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白-胆固醇(LDL-C)与2型糖尿病并发动脉粥样硬化的关系.方法 150例糖尿病患者(实验组)及50例健康对照者(对照组)均采用免疫比浊法测定Hs-CRP,氧化酶法测定TG、TC、一步法测定LDL-C水平,并进行相关性分析.结果 实验组Hs-CRP、TG、TC、LDL-C较对照组明显升高(P<0.001),血糖控制不良组(C组)中Hs-CRP明显高于血糖控制良好组(A组)和血糖控制一般组(B组)(P<0.01),B组高于A组(P<0.01)且与TG、TC、LDL-C正相关.结论 Hs-CRP、TG、TC、LDL-C与2型糖尿病并发动脉粥样硬化密切相关,可作为风险预测指标预测2型糖尿病并发症出现.