21.   G-proteins are natural substances that help cells translate signals emitted by the environment and from within the body into cellular chain reactions that govern fundamental life functions.

22.   Green tea leaves are the least processed of all the teas, preserving the natural active substances of the leaf.

23.   Histamine, a natural substance that constricts airways, makes things worse.

24.   How did the ancient Chinese instinctively know which natural substances contained healing qualities?

25.   Huizenga said a lot of natural substances are sold over the counter.

26.   In April, Thousand Oaks, California-based Amgen surprised observers by becoming the first company to begin human tests of a natural substance for stimulating platelet growth.

27.   In this case, infliximab blocks a natural substance known as tumor necrosis factor-alpha, or TNF-alpha, which promotes inflammation.

28.   Infliximab blocks the action of a natural substance that promotes inflammation.

29.   It is a combination of glucosamine and chondroitin sulfate, natural substances that are centrally involved in the formation of the cartilage that caps the ends of bones.

30.   Moreover, some scientists point out, there are many natural substances in food that breed tumors in rats or mice.