High-density lipoproteins definition

A contribution to the understanding of lipoprotein metabolism would be the definition of the metabolic role of the lysolecithin-rich d 1.21 lipoprotein. This protein-phospholipid complex may simply represent a degradation product of the high-density lipoprotein after removal of the other lipid moieties. On the other hand, it could be considered as a newly synthesized product from the liver on its way to further lipidation to form a more complete class of lipoproteins. Its possible identity with the apolipoprotein described by Roheim and Eder (1961 Roheim et al., 1964) remains to be established. 

The lipoproteins present in plasma may be operationally defined according to their density, as low or very low density lipoproteins and high density lipoproteins, but other, more functional definitions may be more appropriate in connection with in vivo metabolism. Examples are the hpoprotein classes chylomicrons and chylomicron remnants. Alaupovic has suggested a classification based on the apolipoprotein composition [1]. As apolipoproteins often determine the metabolic fate of lipoprotein particles this is a logical approach. Lipoprotein particles with specific apolipoprotein compositions exist in all density fractions of human plasma, as well as plasma from a variety of animal species. 

The consumption of foods high in TFA has been shown to raise low-density lipoprotein cholesterol (LDL or bad cholesterol), which increases the risk of developing coronary heart disease (CHD). This prompted the Food and Drug Administration (FDA) to require mandatory labeling of the fran -fat content in foods. Food manufacturers have to comply by January 1, 2006. The FDA s chemical definition of TFA or trans-fats (TF) is unsaturated fatty acids that contain one or more isolated (i.e., nonconjugated) double bonds in the frani-configuration. ... 

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