Dictionary

isodisomy A remarkable situation in which both chromosomes in a pair are from one parent only. Isodisomy causes some birth defects and is suspected to play a role in cancer. Also known as uniparental disomy.

isochromosome An abnormal chromosome that has two identical arms due to duplication of one arm and loss of the other. Isochromosomes are found in tumors and in some girls with Turner syndrome.

islet of Langerhans A group of specialized cells in the pancreas that make and secrete hormones, including insulin. These cells sit in groups (islets), with several different types of cells in an islet, including alpha cells that make glucagon, which raises the level of glucose (sugar) in the blood; beta cells that make insulin; and…

islet cell tumor A tumor that arises from the islet cells of the pancreas. The islet cells normally produce insulin and other hormones, and so the tumors frequently, but not always, produce one of these hormones. Islet cell tumors can be benign or malignant and generally cause symptoms related to the hormone produced by the…

islet cell transplantation A treatment for diabetes in which insulin-producing islet cells are taken from a donor’s pancreas and transferred into a person with diabetes. Once transplanted, the donor islets begin to make and release insulin, actively regulating the level of glucose in the blood. As with other transplant procedures, immune suppressant drugs must be…

ischium The bone that makes up the lower-rear part of the pelvis. Also known as ischiopubic bar and ischiopubic bone.

ischiopubic synchondrosis The central point of the ischium, which does not close until after the toddler years. See also ischium.

ischiopubic bar See ischium.

ischial bursitis See weaver’s bottom.

ischemia Inadequate blood supply to a local area due to blockage of blood vessels leading to that area. Treatment is directed toward increasing the circulation to the affected body area.

irritable bowel syndrome A functional intestinal disorder of the bowels and their nerves. Irritable bowel syndrome (IBS) may be caused by either abnormal motility (abnormal contractions) of the intestinal muscles or abnormally sensitive nerves in the intestines (visceral hyper-sensitivity). IBS is characterized by abdominal pain, bloating, mucus in stools, and irregular bowel habits, with alternating…

irrigation of the colon The use of liquid solutions given by enema to remove material from the rectum or colon, ostensibly to eliminate toxins from the bowel. Unless ordered by a physician, irrigation of the colon is rarely advisable. Irrigation of the colon carries a number of risks, including interference with the normal digestive process…