• 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 […]

  • Epilepsy, grand mal

    Epilepsy, grand mal: Epilepsy that includes tonic-clonic (grand mal) seizures, which are the most obvious type of seizure. There are two parts to a tonic-clonic seizure. In the tonic phase, the body becomes rigid, and in the clonic phase, there is uncontrolled jerking. A tonic-clonic seizure may or may not be preceded by an aura, […]

  • Lambert-Eaton myasthenic syndrome

    An autoimmune disease characterized by weakness and fatigue of the proximal muscles (those near the trunk), particularly the muscles of the pelvic girdle (the pelvis and hips) and the thighs, with relative sparing of eye and respiratory muscles. Lambert-Eaton myasthenic syndrome (LEMS) is associated in 40% of cases with cancer, most often with small cell […]

  • Environmental Protection Agency

    Environmental Protection Agency: The US government agency founded to “protect human health and to safeguard the natural environment–air, water, and land–upon which life depends.” The Environmental Protection Agency is known as the EPA.

  • Dialysis, peritoneal

    Dialysis, peritoneal: A dialysis technique that uses the patient’s own body tissues inside the belly (abdominal cavity) as a filter. The intestines lie in the abdominal cavity, the space between the abdominal wall and the spine. A plastic tube called a dialysis catheter is placed through the abdominal wall and into the abdominal cavity. A […]

  • Yeast genome

    All of the genetic information contained in yeast (Saccharomyces cerevisiae). The genomes of particular nonhuman organisms such as yeast have been studied for a number of reasons including the need to improve sequencing and analysis techniques. These nonhuman genomes also provide powerful sets of data against which to compare the human genome. For example, a […]