• 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 […]

  • Taenia saginata

    The beef tapeworm. The most common of the big tapeworms that parasitizes people, contracted from infected raw or rare beef. Can grow to be 12-25 feet (3.6-7.5 m) long in the human intestine. Also known as the African tapeworm.

  • Lead-based paint

    Paint or other surface coatings that, by definition, contain lead in excess of 1.0 milligrams per square centimeter (mg/cm2) 0.5 percent by weight. See also lead poisoning.

  • CMV (cytomegalovirus)

    CMV (cytomegalovirus): A virus that infects 50-85% of adults in the US by age 40 and is also the virus most frequently transmitted to a child before birth. Persons with symptoms have a mononucleosis-like syndrome with prolonged fever and mild hepatitis. Once a person becomes infected, the virus remains alive and usually dormant within that […]

  • Nerve, afferent

    A nerve that carries impulses toward the central nervous system.

  • BMT

    BMT: Bone marrow transplantation, a procedure in which doctors replace bone marrow that is diseased (or damaged) with healthy bone marrow. The bone marrow to be replaced may be deliberately destroyed by high doses of chemotherapy and/or radiation therapy. The replacement marrow may come from another person, or it may be the patient’s own marrow […]