progesterone receptor test A lab test that is used to determine whether breast cancer cells have progesterone receptors. If the cells have progesterone receptors, they may depend on progesterone for growth and usually respond to hormone therapy. Breast cancer cells that do not have progesterone receptors do not need the hormone progesterone to grow and…
progesterone A female hormone, the principal hormone that prepares the uterus to receive and sustain fertilized eggs.
progeria One of a group of rare genetic disorders that causes premature aging in children. The classic type of progeria is Hutchinson-Gilford progeria syndrome, which is characterized by dwarfism, baldness, pinched nose, small face and small jaw relative to the head size, delayed tooth formation, aged-looking skin, stiffness of joints, hip dislocations, arteriosclerosis, and heart…
proctosigmoidoscopy An examination of the rectum and the lower part of the colon, using a thin, lighted instrument called a sigmoidoscope.
proctology A medical specialty that deals with disorders of the rectum and anus.
proctitis, ulcerative Ulcerative colitis that is limited to the rectum. See also colitis, ulcerative; proctitis.
proctitis Inflammation of the rectum. Proctitis may be due to a considerable number of causes, including infectious agents and ulcerative colitis. Infectious proctitis is often due to agents such as Chlamydia trachomatis, Neisseria gonorrheae, and herpes simplex virus, all of which can be acquired during anoreceptive intercourse. Proctitis is also a hallmark of ulcerative colitis,…
proclivity An inclination or a predisposition toward something, especially a strong inherent inclination toward something objectionable. For example, a patient might be said to have a proclivity toward alcohol.
process In anatomy, a projection from a structure. For example, the process of the mandible is the part of the lower jaw that projects forward.
probiotic A substance that appears to replenish or support the growth of helpful bacteria in the intestinal tract. The most common probiotic is acidophilus, which is present in yogurt, in acidophilus milk, and in supplements. As the name indicates, probiotics have been developed to counter one unfortunate effect of treatment with antibiotics: the decimation of…
probe 1 In surgery, a slender, flexible rod with a blunt end that is used to explore. 2 In molecular genetics, a labeled bit of DNA or RNA that is used to find its complementary sequence or to locate a particular clone.
proband The family member through whom a family’s medical history comes to attention. For example, a proband might be a baby with Down syndrome. The proband may also be called the index case, propositus (if male), or proposita (if female).