Biomaterial Database

Stability of free apolipoprotein A-1 concentration in serum, and its measurement in normal and hyperlipidemic subjects. 1987

R H Neary, and E Gowland

Free apolipoprotein A-1 (free A-1) is a low-molecular-mass complex of protein and lipid containing apolipoprotein A-1 (apo A-1). Using crossed immunoelectrophoresis, we separated free A-1 from the apo A-1 in high-density lipoproteins (HDL) and quantified free A-1 by comparison with a reference serum (containing 1.45 g of apo A-1 per liter) diluted in 9 mol/L urea solution. This latter treatment yields apo A-1 containing protein-lipid complexes of the same size and electrophoretic mobility as free A-1. Within-day precision (CV), determined by replicate analysis of two samples with mean free A-1 concentrations of 48 and 138 mg/L, was 9.1 and 7.2%, respectively. We also showed that the concentration of free A-1 is not stable in serum or plasma either at 4 degrees C or when frozen. The mean concentration of free A-1 in 28 fasted, healthy subjects was 75.3 (SD 13.6) mg/L. The postprandial increase was not statistically significant. The percentage of total apo A-1 in the free form in serum ranged from 3.5% to 8.1%, less than the 10% to 30% reported by others who used radial immunodiffusion to measure free A-1. Because radial immunodiffusion does not separate free A-1 from HDL, we believe that that technique overestimates free A-1. We also used crossed immunoelectrophoresis to measure free A-1 in 76 hyperlipidemic patients. Those with Fredrickson types III and V had significantly increased concentrations of free A-1 (P less than .0001). Correlations between free A-1 and cholesterol and triglycerides in serum were significant (P less than .005 and P less than .001, respectively). Possible roles for free A-1 in lipid metabolism are discussed.

UI	MeSH Term	Description	Entries
D006951	Hyperlipoproteinemias	Conditions with abnormally elevated levels of LIPOPROTEINS in the blood. They may be inherited, acquired, primary, or secondary. Hyperlipoproteinemias are classified according to the pattern of lipoproteins on electrophoresis or ultracentrifugation.	Hyperlipoproteinemia
D006952	Hyperlipoproteinemia Type III	An autosomal recessively inherited disorder characterized by the accumulation of intermediate-density lipoprotein (IDL or broad-beta-lipoprotein). IDL has a CHOLESTEROL to TRIGLYCERIDES ratio greater than that of VERY-LOW-DENSITY LIPOPROTEINS. This disorder is due to mutation of APOLIPOPROTEINS E, a receptor-binding component of VLDL and CHYLOMICRONS, resulting in their reduced clearance and high plasma levels of both cholesterol and triglycerides.	Autosomal Recessive Hypercholesterolemia,Broad Beta Disease,Dysbetalipoproteinemia,Dysbetalipoproteinemia, Familial,Familial Dysbetalipoproteinemia,Familial Hypercholesterolemia with Hyperlipemia,Hypercholesterolemia, Autosomal Recessive,Hyperlipoproteinemia, Broad-beta,Hyperlipoproteinemia, Type III,Autosomal Recessive Hypercholesterolemias,Broad-beta Hyperlipoproteinemia,Hyperlipoproteinemia, Broad beta,Hyperlipoproteinemias, Type III,Recessive Hypercholesterolemia, Autosomal,Type III Hyperlipoproteinemia,Type III Hyperlipoproteinemias
D006953	Hyperlipoproteinemia Type IV	A hypertriglyceridemia disorder, often with autosomal dominant inheritance. It is characterized by the persistent elevations of plasma TRIGLYCERIDES, endogenously synthesized and contained predominantly in VERY-LOW-DENSITY LIPOPROTEINS (pre-beta lipoproteins). In contrast, the plasma CHOLESTEROL and PHOSPHOLIPIDS usually remain within normal limits.	Hyperprebetalipoproteinemia,Hypertriglyceridemia, Familial,Carbohydrate Inducible Hyperlipemia,Carbohydrate-Inducible Hyperlipemia,Familial Hyperlipoproteinemia Type 4,Familial Type IV Hyperlipoproteinemia,Hyper prebeta lipoproteinemia,Hyperlipoproteinemia, Type IV,Carbohydrate Inducible Hyperlipemias,Carbohydrate-Inducible Hyperlipemias,Familial Hypertriglyceridemia,Hyperlipemia, Carbohydrate Inducible,Hyperlipemia, Carbohydrate-Inducible,Hyperlipemias, Carbohydrate Inducible,Hyperlipemias, Carbohydrate-Inducible,Hyperlipoproteinemias, Type IV,Inducible Hyperlipemia, Carbohydrate,Inducible Hyperlipemias, Carbohydrate,Type IV Hyperlipoproteinemia,Type IV Hyperlipoproteinemias,Type IV, Hyperlipoproteinemia
D006954	Hyperlipoproteinemia Type V	A severe type of hyperlipidemia, sometimes familial, that is characterized by the elevation of both plasma CHYLOMICRONS and TRIGLYCERIDES contained in VERY-LOW-DENSITY LIPOPROTEINS. Type V hyperlipoproteinemia is often associated with DIABETES MELLITUS and is not caused by reduced LIPOPROTEIN LIPASE activity as in HYPERLIPOPROTEINEMIA TYPE I .	Hyperchylomicronemia Late Onset,Hyperchylomicronemia With Hyperprebetalipoproteinemia, Familial,Hyperchylomicronemia, Late-Onset,Hyperlipemia, Combined Fat And Carbohydrate-Induced,Hyperlipemia, Mixed,Hyperlipidemia, Type V,Hyperlipoproteinemia Type 5,Hyperlipoproteinemia, Type V,Hyperchylomicronemia Late Onsets,Hyperchylomicronemia, Late Onset,Hyperchylomicronemias, Late-Onset,Hyperlipemia, Combined Fat And Carbohydrate Induced,Hyperlipemias, Mixed,Hyperlipidemias, Type V,Hyperlipoproteinemia Type 5s,Hyperlipoproteinemias, Type V,Late-Onset Hyperchylomicronemia,Late-Onset Hyperchylomicronemias,Mixed Hyperlipemia,Mixed Hyperlipemias,Type V Hyperlipidemia,Type V Hyperlipidemias,Type V Hyperlipoproteinemia,Type V Hyperlipoproteinemias
D007123	Immunoelectrophoresis, Two-Dimensional	Immunoelectrophoresis in which a second electrophoretic transport is performed on the initially separated antigen fragments into an antibody-containing medium in a direction perpendicular to the first electrophoresis.	Immunoelectrophoresis, Crossed,Immunoelectrophoresis, 2-D,Immunoelectrophoresis, 2D,2-D Immunoelectrophoresis,2D Immunoelectrophoresis,Crossed Immunoelectrophoresis,Immunoelectrophoresis, 2 D,Immunoelectrophoresis, Two Dimensional,Two-Dimensional Immunoelectrophoresis
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D011786	Quality Control	A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required. (Random House Unabridged Dictionary, 2d ed)	Control, Quality,Controls, Quality,Quality Controls
D002850	Chromatography, Gel	Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.	Chromatography, Exclusion,Chromatography, Gel Permeation,Chromatography, Molecular Sieve,Gel Filtration,Gel Filtration Chromatography,Chromatography, Size Exclusion,Exclusion Chromatography,Gel Chromatography,Gel Permeation Chromatography,Molecular Sieve Chromatography,Chromatography, Gel Filtration,Exclusion Chromatography, Size,Filtration Chromatography, Gel,Filtration, Gel,Sieve Chromatography, Molecular,Size Exclusion Chromatography
D004355	Drug Stability	The chemical and physical integrity of a pharmaceutical product.	Drug Shelf Life,Drugs Shelf Lives,Shelf Life, Drugs,Drug Stabilities,Drugs Shelf Life,Drugs Shelf Live,Life, Drugs Shelf,Shelf Life, Drug,Shelf Live, Drugs,Shelf Lives, Drugs