Direct determination of lipoprotein(a) XXXX by ultracentrifugation and agarose gel electrophoresis with enzymatic staining for @entity165 .

@entity1 @entity453 @entity165 @entity3452
Lipoprotein(a) [( @entity3452 )], a low-density lipoprotein (LDL)-like particle, contains in addition to LDL a specific protein component, apolipoprotein(a) [apo(a)]. Conventionally, @entity3452 ) has been measured by immunological methods that distinguish between @entity3452 ) and LDL by dealing with apo(a) as an antigen. We describe a new method to determine @entity3452 ) on the basis of its @entity165 content. Very-low-density lipoproteins were removed from serum by preparative ultracentrifugation at a density of 1.006 kg/L. The infranate was subjected to agarose gel electrophoresis to separate @entity3452 ) and LDL. @entity3452 ) @entity165 was then determined by direct enzymatic staining for @entity165 . On electrophoresis of the > 1.006 kg/L (bottom) fraction, @entity3452 ) migrates to the pre-beta position, regardless of the genetic apo(a) isoform. The interassay CVs of @entity3452 ) @entity165 determinations ranged from 6.9% to 11.5%, and the results correlated well with the @entity3452 ) concentrations measured by immunonephelometry (r = 0.937). There was an inverse relation between the molecular mass of the genetically determined apo(a) isoforms and @entity3452 ) @entity165 concentrations. @entity1 with angiographically proven @entity453 ( @entity453 ) had significantly more @entity3452 ) @entity165 than healthy controls did. The ratio of @entity3452 ) @entity165 to immunologically determined @entity3452 ) tended to be lower in @entity453 @entity1 , suggesting that @entity3452 ) particles contained less @entity165 than apo(a). In addition, the new method allows determination of LDL @entity165 without contamination by @entity3452 ).
