Researchers plan to study the fat-rich particles, called lipoproteins, which circulate in the blood. This study is designed to improve understanding of normal, as well as abnormal, lipoprotein metabolism and the role it plays in the development of hardening of the arteries (atherosclerosis).

Patients participating in this study will receive an intravenous (directly into the vein) injection of a small amount of specially prepared amino acids. The amino acids being injected are the same amino acids present in a normal diet. The amount of amino acid given will be less than the amount eaten in a protein-rich meal. The amino acids will be labeled with nonradioactive heavy isotopes which are also present in the environment n low amounts.

Patients participating in the study will be required to have blood samples taken, and provide urine samples throughout the course of the study. In addition, patient will be required to follow a specially formulated diet. Patients will be weighed throughout the course of the study.