1. III. TECHNOLOGY MILESTONES IN HEALTH AND MEDICINE III.8. Cancer Chemotherapy Evolution of cancer chemotherapy The use of chemicals to treat cancer (cancer chemotherapy) began in 1942 with the clinical use of nitrogen mustards by Louis S. Goodman and Alfred Gilman. Drugs which block folic acid (also called antimetabolites) were also developed. Aminopterin (1947) was effective against leukemia, but its adverse effects on white blood cells quickly led to its replacement by methotrexate. In the 1950s, George Hitchings and Charles Heidelberger developed the antimetabolitic mercaptopurine for leukemia and Fluorouracil for gastrointestinal and breast tumors. Cytotoxic drugs Cytotoxic drugs (or drugs which are poisonous to cells) were isolated from plants and first introduced into cancer chemotherapy in 1963. These anti-cancer drugs work on the principle that rapidly proliferating cells, such as neoplastic (or cancerous) ones, are more susceptible to damage by cytotoxic drugs. Several variations include vinca alkaloids (vincristine and vinblastine) isolated from periwinkle plants and podaphylotoxin isolated from mayapple in 1970. Taxol was isolated from the pacific yew in 1971 and developed to treat advanced breast cancer and lung cancer in the early 1990s. Tamoxifen Tamoxifen, a synthetic molecule developed in 1971, was introduced in 1977 to treat breast cancer by slowing the growth of estrogen-dependent tumors. High estrogen levels promote the cell proliferation in breast tissue, so this type of chemotherapy blocks the natural hormones that can stimulate growth of cancer cells. Megestrol is a synthetic derivative of the naturally occurring steroid hormone, progesterone, which functions in a similar manner and is used in the treatment of recurrent breast tumours. Mammographic image of a breast tumour Personal monitoring of breasts promotes early diagnosis

2. III. TECHNOLOGY MILESTONES IN HEALTH AND MEDICINE III.9. Novel Healthcare Materials Artificial limbs and medical devices Modern artificial limbs and organs, replacement joints, contact lenses and hearing aids, and biomaterials which are crafted from specialized plastics and other high-tech materials have all been produced through chemistry. By manipulating the structures of molecules and creating new ones, chemists and engineers have developed new medical materials that are strong, flexible, and durable. A few such medical devices include the 1945 artificial kidney, the 1950s prosthetic heart valves, and the 1982 surgical implantation of a permanent artificial heart. Plastic contact lenses were introduced in 1956, and soft bifocal contacts were refined in 1985. Medical equipment Chemistry is used to manufacture nearly all of the plastic and vinyl medical devices used in today’s hospitals and health care clinics. Today’s medical equipment must be durable enough for daily use while helping to create a clean, sterile, and germ-free environment. Many routine medical processes utilize state-of-the-art diagnostic equipment, stethoscopes, bandages and other novel fabrics, syringes, surgical instruments, blood bags, and plastic supplies that are produced through chemistry. Even diapers contain hygroscopic polymers that prevent inflammation of the sensitive skin of babies. Disinfectants and bleach Chemistry makes it possible to sanitize your home, breakdown mold and mildew, and remove stains. In the early 1900s, chemists focused on controlling bacteria and cleaning clothes and home surfaces effectively. In 1913, researchers developed a formula for bleach that was affordable and easy to use. Today, bleach is a household commodity and an effective disinfectant which eliminates billions of germs and bacteria. Chlorine is also a powerful weapon against diseases caused by viruses and bacteria in homes, hospitals, and other buildings. Ignatius Semmelweis, the Hungarian gynecologist, was the first to introduce hand washing with chlorine water to his department in 1847. Artificial heart Artificial heart valves