Word: excessive
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Dates: during 1980-1989
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...receptors reach out and grab cholesterol like a first baseman catching a ball thrown by a shortstop," says Dr. Michael Brown of the University of Texas Southwestern Medical Center, who, with his colleague Dr. Joseph Goldstein, won a Nobel Prize in 1985 for discovering LDL receptors. What happens to excess LDLs that are not taken up by cells? Under normal conditions, these are swept by the bloodstream through the liver, where they are captured by cell receptors. The LDLs are then converted into bile acids, which are ultimately excreted...
...cholesterol. Fred may feel great, but every time he eats, his bloodstream is flooded with fatty particles called chylomicrons, which transport triglycerides and cholesterol out of the intestines to the rest of | his body. Soon Fred's liver is busy mopping up chylomicrons and is unable to cope with excess LDL in the blood. The surfeit of cholesterol particles then begins circulating freely through the body. Unless it is stopped, it can lead to the formation of deadly plaque...
...their triglyceride cargoes into the body's cells, the particles become wrinkled like prunes. In the process, fragments containing proteins, fats and cholesterol break away. It is at this point that the unfilled HDL particles come to the rescue by scooping up the detritus. Researchers believe HDL also removes excess cholesterol from fat-sated cells -- perhaps even those in the artery walls...
...particle is transferred to a VLDL ferryboat circulating in the bloodstream; the VLDL then metamorphoses into an LDL, which is picked up by an LDL receptor in the liver. Others think HDL may in fact be a passive player -- a sort of biological signal light that indicates how efficiently excess cholesterol is being removed, without necessarily taking any direct role...
...possibility that has emerged from other studies as well. At Baylor College of Medicine in Houston, Dr. Antonio Gotto Jr. discovered that his heart-bypass patients "almost without exception" have lower levels of HDL and slightly higher levels of triglycerides than people without heart disease. One theory is that excess triglycerides somehow mark HDL particles for elimination by the liver. When this occurs, says Gotto, "there is this Pac-man in the liver chewing up the HDL that ordinarily would be chewing up the plaque in the artery walls...