Glossary of Medical Terms

A nutrient that the body needs in small amounts to function and stay healthy. ATRA is made in the body from vitamin A and helps cells to grow and develop, especially in the embryo. A form of ATRA made in the laboratory is put on the skin to treat conditions such as acne and is taken by mouth to treat acute promyelocytic leukemia (a fast-growing cancer in which there are too many immature blood-forming cells in the blood and bone marrow). ATRA is being studied in the prevention and treatment of other types of cancer. Also called all-trans retinoic acid, retinoic acid, tretinoin, and vitamin A acid.

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called endothelin-1 protein receptor antagonists.

An irregular heartbeat that occurs when the electrical signals in the atria (the two upper chambers of the heart) fire rapidly at the same time. This causes the heart to beat faster than normal. Although atrial fibrillation can occur without any signs or symptoms, it may sometimes cause fatigue, chest pain, heart palpitations, trouble breathing, low blood pressure, dizziness or fainting, weakness, and other signs and symptoms. Atrial fibrillation may be caused by certain conditions, such as high blood pressure, heart attack, coronary artery disease, abnormal heart valves, congenital heart disease, lung disease, viral infections, or an overactive thyroid gland. Previous heart surgery, stress, or exposure to caffeine, tobacco, alcohol, or certain medicines may also lead to atrial fibrillation. It may go away on its own or it may last for many years. If not treated, atrial fibrillation can lead to serious problems, such as blood clots, stroke, and heart failure. It is more common in older adults. Also called afib.

A condition in which the tissues lining the inside of the vagina (birth canal) become thin, dry, and inflamed. This is caused by a decrease in the amount of estrogen (a female hormone) made by the body. Symptoms of atrophic vaginitis include vaginal dryness, itching, and burning, and pain during sexual intercourse. Other symptoms include a burning feeling while urinating, feeling a need to urinate often or right away, and being unable to control the flow of urine. Atrophic vaginitis most commonly occurs in women who have gone through menopause naturally or who have early menopause caused by certain types of cancer treatment (such as radiation therapy to the pelvis or chemotherapy) or by having their ovaries removed by surgery. Also called vaginal atrophy.

A drug used to block nerve stimulation of muscles and glands and relax smooth muscles. It is also used to increase heart rate, reduce secretions, and treat the effects of certain poisons. It is a type of antimuscarinic agent and a type of tropane alkaloid.

A test used to help find out if secretion of pancreatic polypeptide (a protein released by the pancreas) is normal or caused by a tumor. A drug called atropine sulfate is injected into the patient’s vein and level of pancreatic polypeptide in the blood is measured. If there is a tumor, the injection will not change the level of pancreatic polypeptide. If there is no tumor, the level of pancreatic polypeptide will drop.

An aggressive cancer of the central nervous system, kidney, or liver that occurs in very young children. Also called AT/RT and atypical teratoid/rhabdoid tumor.

A medical doctor who is responsible for the overall care of a patient in a hospital or clinic setting. An attending physician may also supervise and teach medical students, interns, and residents involved in the patient’s care.

A disorder with a persistent pattern of inattention and/or hyperactivity and impulsivity.

Weakened or thinned. Attenuated strains of disease-causing bacteria and viruses are often used as vaccines. The weakened strains are used as vaccines because they stimulate a protective immune response while causing no disease or only mild disease in the person receiving the vaccine.