A sex chromosome in certain animals, such as chickens, turkeys, and moths. In humans, males are XY and females XX, but in animals with a Z chromosome, males are ZZ and females are WZ.

Zeta-chain-associated protein kinase 70. A member of the protein tyrosine kinase family, ZAP-70 is normally expressed in T cells and natural killer cells and has a critical role in the initiation of T-cell signaling. ZAP-70 is expressed in T cells and tumors of T-cell lineage. A high level of ZAP-70 expression appears restricted to T-cell […]

‘When you hear hoof beats, think of horses, not zebras.’ For example, when someone develops a mild transient cough, a virus infection is the most logical and likely cause, and tuberculosis is a zebra.

A gene that is lethal (fatal) for the zygote, the cell formed by the union of a sperm (male sex cell) and an ovum (female sex cell). The zygote would normally develop into an embryo, as instructed by the genetic material within the unified cell. However, a zygotic lethal gene scotches prenatal development at its […]

A technique in which a woman’s egg is fertilized outside the body, then implanted in one of her fallopian tubes. This technique is one of the methods used to overcome infertility, the inability of couples to produce offspring on their own. First, the egg and the male sperm needed to fertilize it are harvested. Then […]

Desquamation: The shedding of the outer layers of the skin. For example, when the rash of measles fades, desquamation occurs.

Loss of voluntary movement of the muscles on one side of the face due to abnormal function of the facial nerve (the 7th cranial nerve) which supplies those muscles. Facial nerve paralysis is also called Bell’s palsy. The cause of facial nerve paralysis is often not known, but is thought to be due to a […]

An intervening sequence is the part of a gene that is initially transcribed from the DNA into RNA (specifically, into the primary RNA transcript) but then is excised (removed) from it when the so-called exxon sequences on either side of it are spliced together. Intervening sequences intervene between the exxons. Intervening sequences are also called […]

Atherectomy: A procedure to remove plaque (atheroma) from the inside of a blood vessel. Atherectomy is done most often in major arteries, such as the coronary, carotid, and vertebral arteries, that have experienced the occlusive effects of atherosclerosis. Atherectomy may be accomplished by various means, including angioplasty, laser surgery, conventional surgical incision, or use of […]

Cholesterol lowering with fibrate: The fibrates are cholesterol-lowering drugs that are primarily effective in lowering triglycerides and, to a lesser extent, in increasing HDL-cholesterol levels. Gemfibrozil (brand name: LOPID), the fibrate most widely used in the United States, can be very effective for patients with high triglyceride levels. However, it is not very effective for […]