• Z chromosome

    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.

  • ZAP-70

    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 […]

  • Zebra

    ‘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.

  • Zygotic lethal gene

    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 […]

  • Zygote intrafallopian transfer (ZIFT)

    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 […]

  • Mitochondrial myopathy

    A group of neuromuscular diseases caused by damage to the mitochondria, energy-producing structures in cells that serve as power plants. Nerve and muscle cells require a great deal of energy and are particularly impaired by mitochondrial dysfunction. Some of the more common mitochondrial myopathies include the Kearns-Sayre syndrome, myoclonic epilepsy with ragged-red fibers, and the […]

  • Gingko biloba

    dementia and Alzheimer’s disease, intermittent claudication, glaucoma, memory enhancement, macular degeneration, tinnitus, and Raynaud’s phenomenon. Gingko can cause mild stomach upset and headache and does interact with other non-prescription and prescription medications. Gingko seems also to have blood thinning properties. Therefore, it is not recommended to be taken with aspirin, nonsteroidal anti-inflammatory drugs (such as […]

  • Colitis, mucus

    Colitis, mucus: A common gastrointestinal disorder involving an abnormal condition of gut contractions (motility) and gut sensation (hypersensitivity) characterized by abdominal pain, bloating, mucous in stools, and irregular bowel habits with diarrhea or constipation or alternating diarrhea and constipation, symptoms that tend to be chronic and to wax and wane over the years. Although the […]

  • Y chromatin

    A brilliantly fluorescent body seen under the microscope in cells containing a Y chromosome when the cells are stained with the dye quinacrine. Quinacrine lights up the Y chromosome more than other chromosomes.

  • Resection, video-assisted

    Surgery that is aided by the use of a video camera that projects and enlarges the image on a television screen. Also called video-assisted surgery.