11.   The insufficiency can result from damage to the blood vessels or blockage by plaque, the fatty substance that builds up in atherosclerosis.

12.   The problem appears to be that stents, like the arteries they support, can become blocked by blood clots, scar tissue or new deposits of fatty substances.

13.   They are formed of fatty substances and connective tissue debris that begin to build up at points where the inner lining of the blood vessel has been damaged.

14.   Two new studies are adding importance to health concerns about triglycerides, a fatty substance in the blood that can increase the risk of heart disease.

15.   Children with the disease lack an enzyme to break down a fatty substance in brain cells.

16.   Like a cell membrane, the film also consists of fatty substances called lipids bound together in a polymer or chain.

17.   Scientists mix genes with a fatty substance and inject the concoction directly into tumor cells.