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When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.
For about 100 years, scientists thought that peptic ulcers were caused by stress, spicy food, and alcohol. Later, researchers added stomach acid to the list of causes and began treating ulcers with antacids. Now it is known that peptic ulcers are predominantly caused by Helicobacter pylori, a spiral-shaped bacterium that normally exist in the stomach.
Asthma cases in Americans are about 75% higher today than they were in 1980.
Interferon was scarce and expensive until 1980, when the interferon gene was inserted into bacteria using recombinant DNA technology, allowing for mass cultivation and purification from bacterial cultures.
Human kidneys will clean about 1 million gallons of blood in an average lifetime.