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1.
Summary Phosphowolframate/magnesium chloride, a commonly used precipitation method for the determination of high-density lipoprotein cholesterol in human serum, yields a supernatant containing almost all of the lipoproteins apo A-I and apo A-II but no lipoprotein apo B. The correlation between high-density lipoprotein cholesterol and apo A-I was very high (r=0.94), as well as that between the precipitation method and ultracentrifugal analysis (r>0.95,P<0.001). In contrast, detergent precipitation (for the determination of low-density lipoprotein cholesterol in human serum) produced sediments which contained the major proportion of apo B and only minor amounts of apo A-I and apo A-II. The precipitation method for low-density lipoprotein cholesterol showed very good agreement with ultracentrifugal analysis (r=0.99). Yields of 80.2% were obtained for apo B with both methods. Results obtained using the precipitation methods showed excellent agreement with those obtained using the Friedewald formula (r>0.99). Results were also very similar when hypertriglyceridemic serum samples were briefly centrifuged before analysis of cholesterol, high-density lipoprotein cholesterol and triglyceride values. The present study shows highly significant correlations between cholesterol/high-density lipoprotein cholesterol or low-density lipoprotein cholesterol/high-density lipoprotein cholesterol and apo B/apo A-I ratios (P<0.001). Apo B and apo A-I levels could be used in addition to low- and high-density lipoprotein cholesterol values when assessing the risk of cardiovascular disease, if the methods for determining serum apolipoproteins have been properly standardized.  相似文献   

2.
The association of cancer with low serum total cholesterol is well established. Less clear is the relationship of cancer with the cholesterol distribution among the different lipoprotein classes. Conflicting results have been reported on low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and serum triglyceride levels in different types of tumor. Total serum cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and serum triglycerides were analyzed in 530 patients with newly diagnosed cancer (97 with hematological malignancies, 92 with tumor of the lung, 108 of the upper digestive system, 103 of colon, 32 of breast, and 98 of the genitourinary system) and in 415 non-cancer subjects. Anthropometric (body mass index) and biochemical (serum albumin) indices of nutritional status were also determined in all subjects. Total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, serum albumin, and body mass index were significantly lower in cancer than in non cancer-subjects. The lowest values of total cholesterol, low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol were recorded in patients with hematological malignancies and the highest in patients with breast tumor. All the cancer groups, with the exception of women with breast cancer, showed significantly lower total cholesterol, low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol than age- and sex-matched non-cancer subjects. Multiple regression analysis with low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and triglycerides as dependent variables and sex, age, body mass index, albumin, and cancer (dummy variable) as independent variables, showed that cancer was independently associated with low levels of low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol and with high values of serum triglycerides. Total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, serum triglycerides, body mass index and serum albumin were significantly lower in patients with metastatic than in patients with non-metastatic solid tumor. The significant difference in low-density lipoprotein-cholesterol and serum triglycerides between patients with metastatic and non-metastatic cancer was lost when lipoprotein cholesterol and serum triglyceride levels were adjusted for nutritional variables. The lipid profile in cancer patients is characterized by low low-density lipoprotein-cholesterol, low high-density lipoprotein-cholesterol and relatively high serum triglycerides. The abnormality is a common feature of both hematological and solid tumors and is not entirely explained by poor nutrition.  相似文献   

3.
Five methods for determining low-density lipoprotein cholesterol compared   总被引:3,自引:0,他引:3  
We evaluated three precipitation methods for determination of low-density lipoprotein cholesterol in serum and an indirect method involving the Friedewald formula (Clin Chem 18: 499-502, 1972) by comparison with results by ultracentrifugation. The results of all methods for 83 sera, including 59 hyperlipidemic type IIA, IIB, and IV sera agreed very well, at least for concentrations of serum triglycerides below 8 mmol/L. The accuracy of the Friedewald formula was confirmed in 285 other sera, including 66 sera with triglycerides content between 4.52 and 8.0 mmol/L. For type III sera, the precipitation methods produced similar values to those obtained with the Friedewald formula, all being much higher than the ultracentrifugation values. Density-gradient ultracentrifugation showed that the very-low-density lipoprotein remnants in type III sera almost completely coprecipitated with the low-density lipoproteins. The precipitation methods are not only accurate but also very precise (CV less than 5%); they can therefore be used in clinical laboratories to measure atherogenic low-density lipoproteins plus the remnants of very-low-density lipoproteins. However, when serum triglycerides and high-density lipoprotein cholesterol also are determined, the Friedewald formula is a reliable alternative.  相似文献   

4.
Physiologic pregnancy is associated with a broad series of metabolic adaptations which may also influence the metabolism of lipids and lipoproteins. Although the modification of serum lipids and lipoproteins has been exhaustively investigated during and after pregnancy, the relative changes recorded vary widely among the different studies. A comprehensive lipid and lipoprotein profile was evaluated in 57 women with uncomplicated pregnancies at different gestational ages (20 in the first, 20 in the second, and 17 in the third trimester of pregnancy) and compared to that of 21 non-pregnant women. Conventional lipid parameters, including total cholesterol, high-density lipoprotein cholesterol and triglycerides, were evaluated on the Modular System P. Low-density lipoprotein cholesterol was quantified by the formula of Friedewald, the atherogenic index of plasma was quantified by the formula log (triglycerides/high-density lipoprotein cholesterol), whereas lipoprotein(a) was assayed on the BN II nephelometric analyzer. We observed that all the lipid parameters tested were significantly modified by the gestational age; in particular, women in the second and third trimester displayed significantly increased total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total to high-density lipoprotein cholesterol ratio, lipoprotein(a) and atherogenic index of plasma (third trimester only) when compared to either the control population or the subgroup of women in the first trimester of pregnancy. The value distributions and the relative percentage of women with undesirable or abnormal values according to the current NCEP or AHA/ACC goals were comparable between controls and women in the first trimester. However, when compared with either controls or women in the first trimester, advanced pregnancy was associated with an increased prevalence of undesirable or abnormal values for total cholesterol, low-density lipoprotein cholesterol and triglycerides in the second trimester, and total cholesterol, low-density lipoprotein cholesterol, triglycerides, total to high-density lipoprotein cholesterol ratio and lipoprotein(a) (only from non-pregnant women) in the third trimester. The results of this case-control study demonstrate that physiological pregnancy is associated with a substantial modification of the lipid and lipoprotein metabolism from the second trimester, providing reference ranges for traditional and emerging cardiovascular risk predictors throughout the gestational period.  相似文献   

5.
Cholesterol as well as phospholipids in high-density lipoproteins (HDL) have been measured in 60 serum samples after heparin-manganese chloride precipitation of the apolipoprotein B containing lipoproteins. The values obtained correlated well with values from ultracentrifugal separation (slope 1.11 for cholesterol, 0.92 for phospholipids). Furthermore, there was a significant correlation between the low-density lipoprotein (LDL) cholesterol estimated by the formula of Friedewald et al. and the ultracentrifugally separated LDL cholesterol (slope 1.02). By the additional determination of HDL phospholipids with a precipitation procedure, further information about the "antiatherogenic" is easily available.  相似文献   

6.
Treatment of hypertension with dyslipidemia   总被引:1,自引:0,他引:1  
Lifestyle modifications are the first approach to the treatment of dyslipidemia and hypertension, that is, control of overweight; reduced intake of saturated fat, cholesterol, sodium chloride, and alcohol; and increased physical activity. In high doses, thiazide diuretics and loop diuretics can induce at least short-term increases in levels of total plasma cholesterol, triglycerides, and low-density lipoprotein cholesterol. Low-dose thiazide diuretics do not produce these effects. beta-blockers may increase levels of plasma triglycerides transiently and reduce levels of high-density lipoprotein cholesterol. alpha-blockers may decrease serum cholesterol concentration to a modest degree and increase high-density lipoprotein cholesterol. Angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, calcium antagonists, and central adrenergic agonists have clinically neutral effects on levels of serum lipids and lipoproteins.  相似文献   

7.
The purpose of this study was to investigate the effect of eicosapentaenoic and docosahexaenoic acids on plasma lipids and lipoproteins, lipid peroxidation and antioxidant status in healthy humans. A total of 19 healthy volunteers consumed 6 g/day Maxepa fish oil for 3 weeks (1.8 g n-3 fatty acids/day). At baseline and at day 21, we evaluated plasma lipoproteins, plasma and low-density lipoprotein fatty acids, lipid peroxidation markers (malondialdehyde concentration, low-density lipoprotein peroxidation in vitro), and the content of a number of antioxidants (reduced and oxidized glutathione in whole blood, plasma and erythrocyte glutathione peroxidases, plasma vitamin E and beta carotene). Plasma concentrations of total cholesterol, triglycerides, phospholipids, low-density lipoprotein cholesterol and low-density lipoprotein size did not differ significantly after 3 weeks of supplementation. Adding the fish oil to the diet increased the concentration of n-3 very-long-chain polyunsaturated fatty acids and decreased the concentration of n-6 fatty acid and oleic acid in plasma and low-density lipoprotein. Eicosapentaenoic and docosahexaenoic acid supplementation caused elevated values of the high-density lipoprotein cholesterol due to an increment of the high-density lipoprotein 2 fraction and reduced low-density lipoprotein peroxidation rate in vitro. However, we observed an imbalance between oxidizable substrates and antioxidants with an increased lipid peroxidation, whereas the content of reduced glutathione and beta carotene decreased without any variation in vitamin E. Association of antioxidants with n-3 PUFA could prevent lipid peroxidation and enhance the antiatherogenic effects of n-3 polyunsaturated fatty acids.  相似文献   

8.
The paper contains the study results of some lipid-metabolism indices in patients with severe mechanical injury. Changing concentrations of total cholesterol, triglycerides and of different lipoprotein fractions in blood plasma are demonstrated. It was established that the investigated lipid-metabolism indices reflect a degree of liver malfunction in severely impaired homeostasis. It can be stated on the basis of comparing the study results with the clinical outcome that the dynamic concentration of total cholesterol in blood plasma is an important prognostication factor. Changing ratios of high-density lipoproteins, low-density lipoproteins and extra-low-density lipoproteins were observed in survivors yet by day 15, which is indicative of a commencing dislipidemia.  相似文献   

9.
The effect of serum lipids and lipoproteins on extracranial carotid artery atherosclerosis (CAS) was studied in patients who underwent carotid arteriography. Serum lipid and lipoprotein values along with data on other potential predictors of extracranial CAS were determined in 240 patients who had at least one extracranial carotid artery visualized. In a multiple logistic regression analysis, the independently significant predictors of the presence of extracranial CAS were, in decreasing order of significance, duration of smoking of cigarettes, hypertension, age, and low-density lipoprotein cholesterol. Serum cholesterol, triglycerides, high-density lipoprotein cholesterol, and apolipoprotein A-I did not show an independent effect. Although low-density lipoprotein cholesterol was an independent predictor of the presence of extracranial CAS, its effect as a predictor was far outweighed by the effects of the duration of smoking of cigarettes and a history of hypertension.  相似文献   

10.
We evaluated a method for quantifying high-density lipoprotein cholesterol in plasma, based on electrophoretic migration of the prestained (with Sudan Black III) sample through a discontinuous polyacrylamide++ gel and densitometric integration of the stain associated with each class of lipoprotein. With this method, operations can be carried out on all types of lipoproteins over a broad range of concentrations. Overloading with very-low and low-density lipoproteins did not affect reliability within a wide range of HDL concentrations (0.45 to 16.60 mmol/L). Results for 22 individual plasma samples from normal and dyslipemic subjects correlated well with those by ultracentrifugal analysis (r=0.96; Student's t= 0.90, p > 0.30). We conclude that this method is reliable, sensitive, and accurate, It may be used for simultaneously typing dyslipoproteinemias and assaying HDL cholesterol.  相似文献   

11.
In a study of 1426 males and 1391 females at birth the mean concentrations of cholesterol in total serum, in the sum of very low density and low density lipoproteins and in high density lipoprotein were significantly higher in females than in males. No sex difference was present in the concentration of triglycerides either in total serum or in the lipoprotein fractions.  相似文献   

12.
The purpose of this study was to investigate the effect of eicosapentaenoic and docosahexaenoic acids on plasma lipids and lipoproteins, lipid peroxidation and antioxidant status in healthy humans. A total of 19 healthy volunteers consumed 6 g/day Maxepa® fish oil for 3 weeks (1.8 g n-3 fatty acids/day). At baseline and at day 21, we evaluated plasma lipoproteins, plasma and low-density lipoprotein fatty acids, lipid peroxidation markers (malondialdehyde concentration, low-density lipoprotein peroxidation in vitro), and the content of a number of antioxidants (reduced and oxidized glutathione in whole blood, plasma and erythrocyte glutathione peroxidases, plasma vitamin E and beta carotene). Plasma concentrations of total cholesterol, triglycerides, phospholipids, low-density lipoprotein cholesterol and low-density lipoprotein size did not differ significantly after 3 weeks of supplementation. Adding the fish oil to the diet increased the concentration of n-3 very-long-chain polyunsaturated fatty acids and decreased the concentration of n-6 fatty acid and oleic acid in plasma and low-density lipoprotein. Eicosapentaenoic and docosahexaenoic acid supplementation caused elevated values of the high-density lipoprotein cholesterol due to an increment of the high-density lipoprotein 2 fraction and reduced low-density lipoprotein peroxidation rate in vitro. However, we observed an imbalance between oxidizable substrates and antioxidants with an increased lipid peroxidation, whereas the content of reduced glutathione and beta carotene decreased without any variation in vitamin E. Association of antioxidants with n-3 PUFA could prevent lipid peroxidation and enhance the antiatherogenic effects of n-3 polyunsaturated fatty acids.  相似文献   

13.
Serum paraoxonase 1 (PON1) activity and the oxidation of lipoproteins were investigated in 35 women with pre-eclampsia and in 35 healthy control women with normal pregnancies. Blood pressure, body mass index (BMI), serum levels of total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB) and lipoprotein (a) (Lp[a]), and PON1 activity were assessed. There were no significant between-group differences in subject age, gestational age at diagnosis of pre-eclampsia, BMI, serum total cholesterol, triglycerides, LDL and ApoB levels. Mean systolic and diastolic blood pressures and serum Lp(a) were significantly higher in subjects with pre-eclampsia than in controls. Mean serum HDL, ApoA1 and PON1 activity were significantly lower in subjects with pre-eclampsia compared with controls. In conclusion, lipids and oxidized lipoproteins may play important roles in the pathogenesis of pre-eclampsia.  相似文献   

14.
Lipoprotein(a) (Lp(a)) and the acute-phase proteins, orosomucoid, haptoglobin and alpha 1-antitrypsin, were studied in 32 patients with acute myocardial infarction. Samples were taken at admission and, after fasting overnight, on the following 6 days. In a subgroup of 21 patients total serum cholesterol, high-density lipoprotein (HDL) cholesterol and triglycerides were also estimated. In a linear regression model a significant relation between the relative values of Lp(a) and the time in days was obtained (p = 0.001). Compared with the acute-phase proteins, however, Lp(a) showed a weak increase and the individual responses were very variable. There were no correlations between the individual changes in Lp(a) and the changes in the acute-phase proteins, but Lp(a) changes correlated significantly with the changes in total cholesterol and low-density lipoprotein (LDL) cholesterol. It is suggested that the Lp(a) reaction in myocardial infarction is linked to the reaction of the lipoproteins. There may also be several clinical conditions, including different medications, which influence the Lp(a) level.  相似文献   

15.
Familial chylomicronemia is a rare genetic disorder attributable to the absence of lipoprotein lipase activity or the absence of apo-CII, i.e., the cofactor for the same enzyme. Plasma lipoproteins were analyzed by zonal ultracentrifugation under rate flotation conditions in four patients with lipoprotein lipase deficiency and two patients with apo-CII deficiency. Lipoproteins of density less than 1.006 gm/ml, and particularly lipoproteins with Sf greater than 100, were present in very high concentrations. Low levels of density greater than 1.006 gm/ml lipoproteins were observed. This fraction was composed of some different and discrete lipoprotein populations: intermediate-density lipoproteins (in three of six patients, density = 1.006 to 1.019 gm/ml); low-density lipoprotein LDL2 (in all patients, density = 1.019 to 1.045 gm/ml); low-density lipoprotein LDL3 (in all patients, density = 1.045 to 1.063 gm/ml); high-density lipoprotein HDL2 (in four of six patients); and high-density lipoproteins HDL3 (in all patients). LDL3 was never observed in normal participants by means of zonal ultracentrifugation; this subclass of low-density lipoproteins seems to correspond to LDL particles of very low Sf (2 to 5) previously identified by analytical ultracentrifugation in patients with severe hypertriglyceridemia. LDL3 was isolated by means of zonal ultracentrifugation as a single and discrete peak in all patients. Lipoproteins of density greater than 1.006 gm/ml were rich in triglycerides and poor in cholesterol in comparison with normal lipoproteins. The heterogeneity of low-density lipoproteins (particularly the appearance of LDL3), low levels of total high-density lipoproteins, and lower HDL3 flotation rate than normal are typical aspects of serum lipoproteins in these patients. No significant differences in the lipoprotein profiles of the patients with lipoprotein lipase deficiency in comparison with patients with apo-CII deficiency were found. In both groups of patients, the plasma lipoproteins profile and the altered lipoprotein composition could be related to the impaired catabolism of triglyceride-rich lipoproteins caused by the absence of lipoprotein lipase activity.  相似文献   

16.
We describe a simplified method for measuring high-density lipoprotein cholesterol in serum after very-low- and low-density lipoproteins have been precipitated from the specimen with sodium phosphotungstate and Mg2+. Values so obtained correlate well with values obtained with the heparin-Mn2+ precipitation technique (r = 0.95, CV less than 5% in 66% of the subjects studied and between 5 and 10% in the remaining ones) or by ultracentrifugal separation (r = 0.82, CV less than 5% in 80% of the subjects studied and between 5 and 10% in the remaining ones). Our precipitation technique is more appropriate for routine clinical laboratory use.  相似文献   

17.
A placebo-controlled, double-blind crossover study was carried out in 11 non-insulin-dependent (type 2) diabetic patients to find out the effects of a hepatic enzyme inducer (phenobarbital, 100 mg/day for 2 months) on the metabolic control, plasma C-peptide, insulin, serum, and lipoprotein lipid levels. Phenobarbital induced a significant increase in hepatic antipyrine metabolizing activity, but no significant changes were found in fasting or postload blood glucose, plasma C-peptide, or insulin levels during the study. There was a significant increase in serum total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol, as well as in serum total and very low-density lipoprotein triglycerides, during phenobarbital treatment as compared with placebo.  相似文献   

18.
We compared the results obtained by a micromethod for the determination of plasma lipoprotein cholesterol, in which electrophoresis is used to separate the lipoprotein fractions (beta-, pre-beta-, and alpha-lipoproteins), with those determinations with ultracentrifugation (low-density, very-low-density, and high-density lipoproteins). Precision of determination (coefficient of variation, CV, %) was the same for beta- and low-density lipoproteins (1.6%), and for pre-beta- and very-low-density lipoproteins (3.7%); however, determination of alpha-lipoprotein cholesterol was more precise (1.4%) than that of high-density lipoprotein cholesterol (3.1%). Analytical recovery of lipoprotein cholesterol was the same for both methods (98--100%) and the results were closely correlated (r = 0.943). The procedure has been used to determine the cholesterol content of plasma lipoprotein fractions of apparently healthy adults (both sexes). Lipoprotein cholesterol concentrations in our population sample compare well with those reported for other groups of similar age, in particular Stanford long-distance runners.  相似文献   

19.
BACKGROUND: Combination lipid-lowering therapy may be desirable in patients with elevated low-density lipoprotein cholesterol, high triglycerides, and low high-density lipoprotein cholesterol. This study was conducted to determine the lipid-lowering efficacy of the combination of low-dose simvastatin and niacin in patients with combined hyperlipidemia and low high-density lipoprotein cholesterol. METHODS AND RESULTS: In this multicenter, prospective, randomized trial, 180 patients with hypercholesterolemia and hypertriglyceridemia and/or low high-density lipoprotein cholesterol were randomized to combination simvastatin (10 mg/day) and niacin (0.75 g/day) or to either drug alone for 9 weeks. The dose of niacin was doubled (from 0.75 g/day to 1.5 g/day) in both the combination and niacin arms for the remaining 8 weeks. The combination of simvastatin, 10 mg/day, and niacin, 1.5 g/day, reduced total, low-density lipoprotein, and very low-density lipoprotein cholesterol and triglycerides by 24%, 29%, 45%, and 31%, respectively, while increasing high-density lipoprotein cholesterol by 31%. The addition of niacin to simvastatin did not enhance the low-density lipoprotein cholesterol by 31%. The addition of niacin to simvastatin did not enhance the low-density lipoprotein cholesterol-lowering effect of simvastatin; however, the combination was more effective than either monotherapy at raising high-density lipoprotein cholesterol and lowering very low-density lipoprotein cholesterol (P <.05). More patients discontinued treatment because of an adverse event in the niacin (P <.03) and combination groups (P =.06) than the simvastatin group. CONCLUSIONS: Treatment of patients with combined hyperlipidemia and/or low high-density lipoprotein with combination low-dose simvastatin and niacin resulted in large reductions in total, low-density lipoprotein, and very low-density lipoprotein cholesterol and increases in HDL cholesterol. Although the combination was well tolerated in the current trial, its safety needs to be evaluated in larger trials of longer duration.  相似文献   

20.
A substantial number of treated patients with or at high risk for coronary artery disease continue to have fatal and nonfatal coronary artery events in spite of significant reduction of elevated levels of low-density lipoprotein cholesterol. Other lipoprotein abnormalities besides an elevated level of low-density lipoprotein cholesterol contribute to risk of coronary artery disease and coronary artery events, and the predominant abnormalities that appear to explain much of this continued risk are an elevated serum triglyceride level and a low level of high-density lipoprotein cholesterol. Most patients with coronary artery disease have a mixed dyslipidemia with hypertriglyceridemia, which is associated and metabolically intertwined with other atherogenic risk factors, including the presence of triglyceride-rich lipoprotein remnants, low levels of high-density lipoprotein cholesterol, small, dense, low-density lipoprotein particles, postprandial hyperlipidemia, and a prothrombotic state. Aggressive treatment of these patients needs to focus on these other lipoprotein abnormalities as much as on low-density lipoprotein cholesterol. Combination drug therapy will usually be required. Reliable assessment of risk of coronary artery disease from lipoprotein measurements and response to therapy requires inclusion of all atherogenic lipoproteins in laboratory measurements and treatment protocols. At present this may be best accomplished by use of non-high-density lipoprotein cholesterol (total cholesterol minus high-density lipoprotein cholesterol) calculated from standard laboratory lipoprotein values. Ultimately, a more comprehensive assessment of coronary artery disease risk and appropriate therapy may include measurement of lipoprotein subclass distribution including determination of low-density lipoprotein particle concentration and sizes of the various lipoprotein particles.  相似文献   

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