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     

高密度脂蛋白胆固醇的直接测定法

基于选择性抑制法的原理，通过对聚阴离子和表面活性剂的筛选实验，以及试剂配方和实验条件优化实验，建立了直接测定高密度脂蛋白胆固醇（ＨＤＬ－Ｃ）的方法。本法的线性范围达３．９ｍｍｏｌ／Ｌ，批内ＣＶ为１．４５％～２．０２％；总ＣＶＯ １．７１％～３．１４％，和ＴＰＡ法比较：Ｙ＝０．９９２３Ｘ＋０．０５２，ｒ＝０．０９８３４，ｎ＝６６。加入ＨＤＬ组份的回收率为１００．１％，本法的特异性好，加入ＬＤＬ－Ｃ达     

凝集素亲和沉降法检测碱性磷酸酶糖链结构

目的 建立一种简便的糖蛋白糖链分析方法－－凝集素亲和沉降法。方法 用凝集素亲和沉降法分别检测血清碱性磷酸酶的Ｌ－ＰＨＡ、ＬＣＡ和ＤＳＡ凝集素结合率。结果 批内ＣＶ值分别为４．１％、２．３％和３．４％，批间ＣＶ值分别为５．７％、３．８％和４．３％，与凝集素亲和层析法测定结果的相关系数分别为０．９８５、０．９８０和０．９７８。并用此法对３０例健康者和５７例不同肝病患者血清碱性磷酸酶Ｌ－ＰＨＡ、ＬＣＡ和     

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，磷惭酸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６５．０９６Ｕ／Ｌ时，ＣＶ分别     

^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＾－     

高密度脂蛋白胆固醇直接测定法与硫酸葡聚糖50-镁法比较

目的评价高密度脂蛋白胆固醇（ＨＤＬ－Ｃ）直接测定法在临床应用的可行性。方法将直接测定法与硫酸葡聚糖（ＤＳ５０）－氯化镁沉淀法进行比较，并分析其线性范围、准确度和干扰因素。结果直接法与ＤＳ５０沉淀法相关良好，Ｙ＝０．９２７Ｘ＋０．２１４，ｒ＝０．９６４，ＨＤＬ－Ｃ浓度为２．４５ｍｍｏｌ／Ｌ范围内线性良好，ｒ＝０．９９９，ＨＤＬ－Ｃ浓度两组低、中、高值血清标本（０．８４、１．３１、２．３１；０．９２、１．４２、２．５３ｍｍｏｌ／Ｌ）的批内和批间ＣＶ值分别为２．３８％、１．１５％、２．４７％和３．４８％、０．９９％、２．０６％。浓度为１０．５８ｍｍｏｌ／Ｌ甘油三酯并不影响ＨＤＬ－Ｃ直接测定法。结论ＨＤＬ－Ｃ直接测定法简易快速，结果准确，适于自动化分析。     

血清结合胆红素的酶法测定

目的 建立用胆红素氧化酶（ＢＯＤ）作为催化剂，选择性地测定血清结合胆红素（ＣＢ）的新方法。方法 测定条件为：０．１ｍｏｌ／Ｌ甘氨酸缓冲液、ｐＨ１０．０，ＢＯＤ活性０．５～０．８Ｕ／反应管，反应时间２分钟。结果 线性至少可达到２２０μｍｏｌ／Ｌ；精密度为批内ＣＶ１．７１～３．９８％、批间ＣＶ８．０～９．７２％；正常参考值范围为０～３．１４μｍｏｌ／Ｌ；与偶氮法所测结果相关性较好。结论 本文所建立的Ｃ     

聚乙二醇修饰酶法直接测定高密度脂蛋白胆固醇的评价

本文用德国Ｂｏｅｈｒｉｎｇｅｒ Ｍａｎｎｈｅｉｍ公司生产的高密度脂蛋白胆固醇试剂盒在Ｄｌｙｍｐｕｓ ＡＵ－５６０型生化仪上建立了直接法测定血清ＨＬＤ－Ｃ的程序，并对此方法作了初步评价。ＨＤＬ－Ｃ浓度在２．６ｍｍｏｌ／Ｌ范围内线性良好，ｒ＝０．９９９；两组低，中，高浓度的标本批内ＣＶ２．１％－３．３％，批间ＣＶ２．２％－３．６％，平均回收率为９７．５％，浓度为６．２ｍｍｏｌ／Ｌ甘油三酯，１０５．６μ     

HCV在肝病患者中的感染模式及其免疫状况研究

对４１６例病毒性肝炎患者进行了抗－ＨＣＶ及其它血清标志物检测，结果共发现５２例抗－ＨＣＶ阳性患者，其中单独抗－ＨＣＶ阳性占２３．０％，与ＨＢＶ感染占４０．４％，与ＨＢＶ、ＨＤＶ感染占９．６％。抗－ＨＣＶ在慢性活动型肝炎、肝硬化中的阳性率分别为３０．４％和２２．７％，明显高于急性肝炎和非甲非乙型肝炎中的阳性率（２．８％、１３．０％），提示ＨＣＶ在促使肝病慢性化及加重病情方面有重要作用。对抗－ＨＣＶ阳性患者外周血Ｔ淋巴细胞分型结果显示：各型丙肝息者ＣＤ＿３、ＣＤ＿４比例均下降，而ＣＤ＿８比例上升，表现为Ｔｈ细胞功能下降，Ｔｓ细胞功能增强，提示细胞免疫功能紊乱是丙肝患者高慢性化率的免疫学基础。     

连续监测法测定血清山梨醇脱氢酶

以ＮＡＤ＋、山梨醇为底物，３７℃ｐＨ１０的甘氨酸／氢氧化钠为缓冲体系，建立血清山梨醇脱氢酶（ＳＤＨ）的连续监测法。ＮＡＤ＋、山梨醇和Ｚｎ２＋的最终浓度分别为０．４７、１９和１．９ｍｍｏｌ／Ｌ，ＫＮＡＤ＋、Ｋ山梨醇分别为０．０９和１．２ｍｍｏｌ／Ｌ。在此条件下，确定ＳＤＨ线性范围为０～１８０Ｕ／Ｌ，批内ＣＶ为３．９％，批间ＣＶ为５．２％，６０例健康成人血清ＳＤＨ正常参考值为０～３．１Ｕ／Ｌ。初步临床观察表明，急性肝损伤时该酶明显升高，肝外梗阻、心肌梗塞等非肝病患者血清ＳＤＨ一般不增高。     

Simultaneous determination of serum cholesterol in high- and low-density lipoproteins with use of heparin, Ca2+, and an anion-exchange resin.

Cholesterol concentrations in serum high-density and low-density lipoproteins are simultaneously determined simply, specifically, and rapidly by use of the precipitation method with heparin, Ca2+, and an anion-exchange resin. The isolation of lipoproteins is reproducible, selective, and complete, as judged by electrophoresis on polyacrylamide gel and by immunoelectrophoresis, with use of samples with very-low-density lipoprotein triglyceride concentrations of less than 3.5 g/liter. The precision of the present method is as good (CV, 2.8-3.1%) as that for the method used by the U.S. Lipid Research Clinics (CV 2.0-3.2%). The present method and the heparin-Mn2+ method of the Clinics gave results that agreed reasonably well (for low-density-lipoprotein cholesterol r = 0.935, P less than 0.001; for high-density-lipoprotein cholesterol r = 0.837, P less than 0.001). we also describe the relations between high- or low-density lipoprotein cholesterol and total cholesterol, and between cholesterol concentrations in these two lipoprotein classes.     

Mathematical evaluation of methods for estimation of the concentration of the major lipid components of human serum lipoproteins.

The concentration of total cholesterol and triglycerides in the three major lipoprotein classes of human serum was measured in 136 men, randomly selected from an industrial population, by a quantitative method of lipoprotein electrophoresis on agarose gel and of fractions separated by preparative ultracentrifugation. Correlation coefficients for the two estimates were 0.98 for triglycerides in very low-density lipoproteins, 0.93 for total cholesterol in low-density lipoproteins, and 0.75 for total cholesterol in high-density lipoproteins. Data obtained form the analyses of the ultracentrifugal fractions were used to develop regression equations that predict the concentrations of total cholesterol and triglycerides in the lipoprotein classes from their concentrations in whole serum. These equations take into account the inverse curvilinear relationship between total cholesterol in high-density lipoproteins and serum tiriglyceride concentration. When applied to a separate sample of 530 men, the predicted values for triglycerides in very low-density lipoproteins and total cholesterol in low-density lipoproteins correlated as well with ultracentrifugal values as did the electrophoretic estimates. However, for total cholesterol in high-density lipoproteins, the electrophoretic method was superior. Similar regression equations were developed from ultracentrifugal lipoprotein analyses in 158 women from the same industrial population. Although the concentration of total cholesterol in the low-density lipoproteins estimated by both electrophoresis and the regression equations agreed closely in most cases with the ultracentrifugal values, errors exceeded 10% with sufficient frequency to limit the value of the estimates for this purpose. In both men and women, the ratio of total cholesterol to triglycerides in high-density lipoproteins was a hyperbolic function of serum triglyceride concentration, suggesting that cholesteryl esters in the core of this lipoprotein are progressively replaced by triglycerides as the concentration of triglycerides in very low-density lipoproteins increases. This altered composition of nonpolar lipids accounts, at least in part, for the reduction of cholesterol in high-density lipoproteins in hyperlipemic individuals.     

High-density lipoprotein subfractions in normolipidemic individuals without clinical atherosclerosis lipoprotein subfractions in an adult population

This study evaluated the serum concentrations of lipids, lipoproteins, apolipoproteins, and high-density lipoprotein (HDL) subfractions in Brazilian adults. We analyzed the distribution of lipids in HDL2 and HDL3 in a normolipidemic population without evidence of established cardiovascular disease (CVD). A total of 93 males and 92 females, healthy and normolipidemic, volunteered to be submitted to a clinical examination, a blood collection, and to answer a questionnaire aimed at determining signs and symptoms of atherosclerotic disease. Their fasting plasma lipid, lipoproteins, apolipoproteins, and the cholesterol and triglyceride concentrations in HDL2 and HDL3, isolated by microultracentrifugation, were determined by enzymatic-colorimetric methods. The interpercentile intervals (2.5-97.5) for the population were established as being 5-18 mg/dL in men and 4-28 mg/dL in women for HDL2 cholesterol (HDL2chol) and 1-57 mg/dL in men and 2-61 mg/dL in women for HDL3 cholesterol (HDL3chol). HDL2 triglyceride levels (HDL2Tg) in men were 1-26 mg/dL and in women 2-28 mg/dL; moreover, the HDL3 triglyceride (HDL3Tg) intervals were established as 4-46 mg/dL for both sexes. The determination of reference ranges for lipids in HDL subfractions in populations without clinical atherosclerosis, is an useful tool for metabolic, diagnostic, and therapeutic approaches. We determined the intervals for HDL2chol, HDL3chol, HDL2Tg, and HDL3Tg. There were variations with sex and/or age for HDL2chol, HDL3chol, and HDL2Tg in the studied population.     

Estrogen treatment of prostate cancer increases triglycerides in lipoproteins as demonstrated by HPLC and immunoseparation techniques

BACKGROUND: Estrogen administration is known to increase serum triglyceride concentrations. This study measured changes in lipoproteins of patients with prostate cancer treated with estrogen to determine whether the increased triglyceride concentrations are associated with atherogenic lipoprotein patterns. METHODS: Fifteen patients (52-87 years) with histologically diagnosed prostate cancer received diethylstilbestrol diphosphate (250 mg/day). Serum samples were collected before and after 1 and 2 weeks of treatment. Cholesterol and triglyceride profiles of major lipoproteins were determined by HPLC, remnant-like particle cholesterol and triglyceride concentrations by an immunoseparation technique, and apolipoproteins by immunologic methods. RESULTS: Estrogen treatment induced a 63.3% increase in total triglyceride concentrations, which occurred in all major lipoprotein classes with significant increases in HDL-triglycerides (130.4%), LDL-triglycerides (60.7%) and VLDL-triglycerides (56.2%). HDL-cholesterol increased significantly by 26.8%, while LDL-cholesterol decreased (15.6%). Remnant-like particle triglyceride concentrations also increased significantly by 77%, whereas remnant-like particle cholesterol concentrations remained unchanged. Apolipoproteins A-I and A-II increased; apolipoprotein E and Lp(a) decreased. CONCLUSIONS: The techniques used here conveniently demonstrated that short-term estrogen treatment in prostate cancer patients resulted in triglyceride enrichment of all major lipoprotein classes but did not induce changes in the lipoprotein profiles generally recognized as increasing risk for cardiovascular disease, except for the elevation of plasma triglyceride and remnant-like particle triglyceride.     

Separation of two serum very low density lipoprotein fractions using starch block electrophoresis.

A quantitative electrophoretic method has been developed in order to differentiate very low density (VLDL) pre-beta lipoproteins from late pre-beta lipoproteins using starch as a supporting medium. It was possible to obtain a bimodal distribution of lipoprotein lipids from VLDL which on agarose gel electrophoresis had a pre-beta band and a late pre-beta band. Optimal conditions were: ammonium carbonate buffer, mu = 0.025, dialysis prior to electrophoresis. Agarose gel electrophoresis demonstrated that the fast and slow components obtained on starch block electrophoresis corresponded to the pre-beta and late pre-beta band respectively. With increasing migration towards the anode the ratio of cholesterol to triglycerides decreased continuously. It is suggested that the fast triglyceride rich component represent newly secreted VLDL species and the slower component mainly postlipolytic particles. The pre-beta band on agarose gel electrophoresis might represent more newly secreted VLDL than the late pre-beta band. However, it cannot be excluded that part of late pre-beta lipoproteins may be secreted de novo.     

Lipid composition and lipopolysaccharide binding capacity of lipoproteins in plasma and lymph of patients with systemic inflammatory response syndrome and multiple organ failure

BACKGROUND: Lipopolysaccharide (LPS), the major glycolipid component of Gram-negative bacterial outer membranes, is a potent endotoxin responsible for many of the directly or indirectly induced symptoms of infection. Lipoproteins (in particular, high-density lipoproteins) sequester LPS, thereby acting as a humoral detoxification mechanism. PATIENTS: Differences in the lipoprotein composition in human plasma and lymph of a control patient group (n = 5) without systemic inflammatory response syndrome (non-SIRS/MOF) and patients with SIRS and multiple organ failure (MOF, n = 9) were studied. The LPS binding capacity of the lipoproteins in SIRS/MOF and non-SIRS/MOF patients was investigated by rechallenge of the plasma and lymph with fluorescently labeled LPS ex vivo. The lipoprotein composition was analyzed using immunochemical techniques and high-performance gel permeation chromatography. RESULTS: In the non-SIRS/MOF patient group, plasma and lymph levels of apolipoprotein A-I (600 and 450 mg/L, respectively), apolipoprotein B (440 and 280 mg/L, respectively), total cholesterol (2.88 and 1.05 mM, respectively), and total triglycerides (0.67 and 0.97 mM, respectively) were observed. In the SIRS/MOF group, a decrease of apolipoprotein A-I (-55% in plasma and lymph), a decrease of apolipoprotein B (-43% in plasma and -38% in lymph), and a decrease of total cholesterol levels (-54% in plasma and -37% in lymph) were demonstrated. However, the triglyceride levels in the SIRS/MOF group showed a 30% increase in plasma and a 47% decrease in lymph compared with the non-SIRS/MOF patients. In SIRS/MOF patients, a 2.8-fold increase in plasma and a 1.8-fold increase in lymph of the LPS low-density lipoprotein/high-density lipoprotein ratio was observed, indicating that the relative LPS binding capacity of the lipoproteins in the SIRS/MOF patient group showed a trend to be shifted mainly toward low-density lipoproteins. Furthermore, in plasma and lymph of four SIRS/MOF patients, a novel cholesterol-containing high-density lipoprotein-like particle was found that barely had LPS binding capacity (<5%). CONCLUSIONS: In the SIRS/MOF patients, the changes in lipoprotein composition in lymph are a reflection of those in plasma, except for the triglyceride levels. In comparison with the non-SIRS/MOF patients, the SIRS/MOF patients show a shifted LPS binding capacity of high-density lipoproteins toward low-density lipoproteins in plasma and in lymph. Moreover, in plasma and lymph, novel cholesterol-containing particles, resembling high-density lipoprotein, were identified in the SIRS/MOF patient group.     

Radioimmunoassay studies of human apolipoprotein E.

This report describes the development and first applications of a sensitive and specific double antibody radioimmunoassay for human apoplipoprotein E (apoE). ApoE was purified from the very low density lipoproteins of hypertriglyceridemic patients by heparin-agarose affinity chromatography, DEAE-cellulose chromatography, and preparative polyacrylamide gel electrophoresis. The purified apoprotein had an amino acid composition characteristic of apoE and resulted in the production of monospecific antisera when injected into rabbits. The radioimmunoassay, which was carried out in the presence of 5 mM sodium decyl sulfate, had a working range of 0.8-12 ng. The withinassay coefficient of variation was 9% and the coefficient of variation for systematic between-assay variability was 3%. Prior delipidation of samples with organic solvents did not alter their immunoreactivity. In 26 normal volunteers, the mean plasma apoE concentration was 36 +/- 13 microgram/ml. Hyperlipidemic patients (n = 68) had higher mean apoE levels. A single patient with type III hyperlipoproteinemia had a plasma apoE level of 664 microgram/ml. The plasma apoE level was independently related to plasma cholesterol and triglyceride levels in a population of 108 normal and nonchylomicronemic hyperlipidemic patients. The multiple correlation coefficient for this relationship was 0.73. Thus, variation in plasma cholesterol and triglyceride concentrations described 53% of the variation in apoE concentrations in this population. The lipoprotein distribution of apoE was investigated by agarose column chromatography and ultracentrifugation of plasma. Agarose column chromatography demonstrated that all or nearly all plasma apoE is associated with lipoproteins. In plasma from normal volunteers and hypercholesterolemic patients, apoE was found in two discrete lipoprotein classes: very low density lipoproteins and a set of lipoprotein particles with size and density characteristics similar to HDL2. In hypertriglyceridemic patients, nearly all apoE was associated with the triglyceride-rich lipoproteins.     

Lipoprotein profiles in plasma and interstitial fluid analyzed with an automated gel-filtration system

BACKGROUND: High-quality methods for lipoprotein characterization are warranted in studies on various metabolic diseases. MATERIALS AND METHODS: An automated system for size-exclusion chromatography (SEC) of lipoproteins using commercially available components is described. Cholesterol or triglyceride content in separated lipoproteins from plasma and interstitial fluid (IF) was continuously determined on-line using microlitre sample volumes. RESULTS: The lipoprotein assay showed a good concordance with the classic ultra-centrifugation/precipitation technique using fresh or frozen samples. Determination of lipoproteins in IF obtained from vacuum-induced skin blisters from 18 healthy subjects revealed that very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol levels were 18%, 19% and 25%, respectively, of concomitant plasma concentrations. The size-exclusion chromatography (SEC) system also allows for triglyceride determination on-line and it could be shown that the system is advantageous for an accurate determination of triglycerides in conditions when there are high levels of glycerol, e.g. in mice and in patients with hyperglycerolaemia (pseudo-hypertriglyceridaemia). CONCLUSIONS: The described system should be of value in studies where detailed lipoprotein analysis is warranted and particularly when significant sample series with small volumes are available. Our data also suggest that there is a 4-5.5-fold concentration gradient between plasma and IF for the three major plasma lipoproteins.     

Effect of heparin-induced lipolysis on the distribution of apolipoprotein e among lipoprotein subclasses. Studies with patients deficient in hepatic triglyceride lipase and lipoprotein lipase

In normal subjects, apolipoprotein E (apo E) is present on very low density lipoproteins (VLDL) (fraction I) and on particles of a size intermediate between VLDL and low density lipoproteins (LDL) (fraction II). The major portion of apo E is, however, on particles smaller than LDL but larger than the average high density lipoproteins (HDL) (fraction III). To investigate the possible role of the vascular lipases in determining this distribution of apo E among the plasma lipoproteins, we studied subjects with primary deficiency of either hepatic lipase or of lipoprotein lipase and compared them with normal subjects. Subjects with familial hepatic triglyceride lipase deficiency (n = 2) differ markedly from normal in that fraction II is the dominant apo E-containing group of lipoproteins. When lipolysis of VLDL was enhanced in these subjects upon release of lipoprotein lipase by intravenous heparin, a shift of the apo E from VLDL into fractions II and III was observed. In contrast, apolipoproteins CII and CIII (apo CII and CIII, respectively) did not accumulate in intermediate-sized particles but were shifted markedly from triglyceride rich lipoproteins to HDL after treatment with heparin. In subjects with primary lipoprotein lipase deficiency (n = 4), apo E was confined to fractions I and III. Release of hepatic triglyceride lipase by heparin injection in these subjects produced a shift of apo E from fraction I to III with no significant increase in fraction II. This movement of apo E from large VLDL and chylomicron-sized particles occurred with little hydrolysis of triglyceride and no significant shift of apo CII or CIII into HDL from triglyceride rich lipoproteins. When both lipoprotein lipase and hepatic triglyceride lipase were released by intravenous heparin injection into normal subjects (n = 3), fraction I declined and the apo E content of fraction III increased by an equivalent amount. Either moderate or no change was noted in the intermediate sized particles (fraction II). These data strongly support the hypothesis that fraction II is the product of the action of lipoprotein lipase upon triglyceride rich lipoproteins and is highly dependent on hepatic triglyceride lipase for its further catabolism. In addition, the hydrolysis by hepatic triglyceride lipase of triglyceride rich lipoproteins in general results in a preferential loss of apo E and its transfer to a specific group of large HDL.     

Plasma lipids, lipoproteins and apoproteins in a case of apo C-II deficiency

A new case of apo C-II deficiency is described. The patient had plasma triglyceride levels ranging from 10.2–30.5 mmol/1. Apo C-II deficiency was confirmed by gel electrophoresis, isoelectric focusing and immunochemistry.

In this patient plasma lipoproteins were mainly chylomicrons and very low density lipoproteins, LDL and HDL levels being very low. Infusion of normal plasma effectively reduced plasma triglycerides and enhanced low density and high density lipoproteins cholesterol levels. These data suggest that in vivo a precursorproduct relationship exists between triglyceride rich lipoproteins and LDL and HDL, and further stress the role of the lipoprotein lipase-apo C-II system in modulating these metabolic interconversions.