Serum Lipid Disorders Research Articles

Screening for Dyslipidemia:Practice Parameter

Screening for serum lipid disorders is recommended by numerous specialty societies to identify patients at risk for coronary heart disease (CHD). The best screening tests will identify patients at highest risk for CHD who would benefit from intervention. This report discusses an appropriate test panel to use as the initial screen on a healthy outpatient population, and the required accuracy and precision of the tests from the Laboratory Medicine perspective. Controversy exists regarding which methods to use and at what age testing should begin. The following parameters will be modified as studies continue and new tests are developed. The recommendations are as follows: (1) Total serum cholesterol (TC) and high density lipoprotein-cholesterol (HDL-C) are presently the recommended screening tests for dyslipidemia in the general population; (2) The National Cholesterol Education Program (NCEP) recommends measuring TC and HDL-C in adults with a single sample at 5-year intervals beginning at age 20; (3) The NCEP recommends measuring TC in children with at least one parent having TC > or = 6.24 mmol/L (> or = 240 mg/dL); (4) The NCEP recommends a lipoprotein analysis consisting of a 12-hour fasting TC, HDL-C, triglyceride, and estimated low density lipoprotein-cholesterol (LDL-C) in adults with the following results: (a) TC > or = 6.24 mmol/L (> or = 240 mg/dL); (b) borderline TC of 5.20-6.23 mmol/L (200-239 mg/dL) and HDL-C < 0.91 mmol/L (< 35 mg/dL) or two or more risk factors; (c) desirable TC of < 5.20 mmol/L (< 200 mg/dL), but HDL-C < 0.91 mmol/L (< 35 mg/dL); (5) The NCEP recommends a lipoprotein analysis in children with documented CHD in a parent or grandparent, or in children that have a TC of > or = 5.20 mmol/L (> or = 200 mg/dL); (6) Two or three separate lipoprotein analyses should be done to confirm the LDL-C result before therapeutic intervention. Specimens should be tested from 1 to 8 weeks apart and the results averaged to account for physiologic variability; (7) Enzymatic methods are preferred for TC determination, and should be standardized and traceable to the reference method and materials at the Centers for Disease Control and Prevention (CDC); (8) The analytic method for TC should have a bias against the reference method of < 3% and a within laboratory reproducibility of < 3% coefficient of variation; (9) Chemical precipitation methods are preferred for HDL-C determination.(ABSTRACT TRUNCATED AT 250 WORDS)

Clofibrate therapy and gallstone induction.

Two hundred consecutive patients, referred to a clinic established for the management of serum lipid disorders, were studied to assess the prevalence of gallbladder disease: 163 patients agreed to cholecystography of whom 23 had gallstones; 5 other patients had had cholecystectomy. There was a strong associction between clofibrate therapy and gallstones, which were found in 9 of 18 patients. Fifty-six patients with normal gallbladders had duodenal bile analyzed for lipid composition, and results were compared with those from 15 other patients with gallstones but normal serum lipids. Bile in hyperlipidemia and normolipidemic controls contained less cholesterol (9.21±3.48 mol/100 mol) than in clofibrate-treated patients (13.33±3.48 mol/100 mol, P<0.01), and in gallstone patients with normal serum lipids (11.87±4.52 mol/100 mol). There was no relationship demonstrable between patterns of hyperlipidemia or ischemic heart disease and the presence of gallbladder disease. There was also no association between biliary lipid composition and serum lipids or low-animal-fat diet. It is concluded that clofibrate therapy markedly increases biliary cholesterol content and is a potent lithogenic agent in patients not otherwise especially prone to gallstones. Since its role in prevention of ischemic heart disease is now uncertain, its continued wide use warrants close scrutiny.

各種血清脂質異常例におけるリポ蛋白質PAG電気泳動像の観察

With the development of a practical method of polyacrylamide gel (PAG) electrophoresis of serum lipoproteins, sophisticated studies on serum lipid or lipoprotein disorders in atherosclerotic cardiovascular patients became possible. Qualitative and quantitative disorders of serum lipoproteins are estimated adequately even in modest to moderate hyperlipidemias which are quite prevalent among atherosclerotic cardiovascular patients. The objective of this presentation is to relate electrophoretic profiles of serum lipoproteins worked out with PAG disc method on an approximately 1815 clinical subjects.Serum lipoprotein PAG disc electrophoretic profiles could be classified as six basic lipoprotein patterns. Four of six basic patterns seemed being consistent with the patterns of four of the established cases with familia hyperlipoproteinemia of WHO and other classifications, though none of our subjects had any clinical evidence of familial disorders. Presence of the midband lipoproteins and chylomicrons were major sources of a considerable number of the variations of the six basic patterns.Occurrence of dense and wide midband was relatively rare in hyperpre-bata lipoproteinemia. In this abnormality, fluctuation of serum triglyceride concentration is evidently ascribable to chylomicrons which is clearly separated from pre-beta or beta lipoproteins with PAG method. The mixed hyperlipoproteinemia (referred to as the sixth phenotype by some) is detectable and identifiable with the method. Lipid chemistry of this abnormality was frequently indif f erentiable from those of other hyperlipoproteinemias. Dense and wide midband was detected frequently among hyperbeta lipoproteinemia with or without. moderately detectable pre-beta lipoprotein, though occurrence of the midband per se was not differred from the others. The midband showed considerable variations in electrophoretic characters. Hypercholesterolemia was common in these subjects, but triglyceride level was variable. Among the variations of normal lipoprotein pattern, the most interesting was those with dense and wide midband in addition to normal beta lipoprotein band. Some of them showed hypercholesterolemia and some others showed hypertriglyceridemia. Following drug therapy for hyperlipidemia, quantitative and qualitative changes of serum lipoprotein profiles were observable frequently.These observations suggest that serum lipid abnormalities may appear as variable forms of abnormal spectra of lipoprotein species, although there is a rough interrelationship between serum lipoprotein abnromalities and lipid abnormalities.

Pre-Beta Lipoproteinemia : Its Bearing on the Dietary Management of Serum Lipid Disorders as Related to Ischemic Heart Disease

Serum triglyceride and cholesterol levels were determined in 672 men aged 50-65, 83 of whom had ischemic heart disease. Simultaneously obtained samples of plasma were subjected to paper electrophoresis in albumin-containing buffer and stained for lipoproteins. The presence of a pre-beta band indicative of endogenous triglyceride and lipid staining material at the origin, indicative of dietary triglyceride, was observed. These procedures were also carried out in 50 students aged 20-25 and in 40 patients referred in consultation for gross serum-lipid elevations. With the exception of one patient in the last group, who had true fat-induced lipemia, all subjects with elevated triglyceride levels (greater than 5.2 mEq/liter) exhibited a pre-beta band, demonstrating that the commonly encountered triglyceride elevation in middle age is endogenous in origin. A pre-beta band was present in 30% of young men, but was of faint intensity. In middle-aged men, 84% with ischemic heart disease and 76% without it exhibited a pre-beta band of varying intensity. A positive correlation was observed between the intensity of staining of the pre-beta band and the serum triglyceride and cholesterol level. Reduction of serum triglyceride levels in subjects with gross hyperglyceridemia by caloric restriction or carbohydrate restriction or with the use of Atromid S alone was associated with a parallel reduction in intensity of the pre-beta band and associated reduction in cholesterol and triglyceride. The occurrence of this type of lipoprotein disorder of less severe degree in a relatively large percentage of the general population suggests that similar therapy may be effective in this group. It is believed that a serum cholesterol determination alone in subjects with elevated cholesterol levels is inadequate when dietary management is contemplated. For rational therapy, this determination should be supplemented with a triglyceride determination or paper electrophoresis of plasma lipoproteins, or both.