• 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 […]

  • Bias

    Bias: 1. When a point of view prevents impartial judgment on issues relating to the subject of that point of view. In a clinical trial, bias refers to effects that a conclusion that may be incorrect as, for example, when a researcher or patient knows what treatment is being given. To avoid bias, a blinded […]

  • Methemoglobinemia

    MedscapeReference.com. Methemoglobinemia in Emergency Medicine.

  • Cat scratch fever

    Cat scratch fever: An infection caused by the Bartonella henslae bacteria. Almost half of all domestic cats carry these bacteria and can transmit it to humans through a scratch or bite. Cat scratch fever causes swelling of the lymph nodes, sore throat, fatigue, fever, chills, sweats, vomiting, loss of appetite, and weight loss. There is […]

  • Wordprocessor’s cramp

    A form of focal dystonia caused by wordprocessing that affects the muscles of the hand and, sometimes, the forearm. The term “dystonia” refers to a state of abnormal (too much or too little) muscle tone. There are many forms of dystonia. Dystonia disorders cause involuntary movements and prolonged muscle contraction, resulting in twisting body motions, […]

  • Drug, sulfa

    Drug, sulfa: One of the sulfonamides, the sulfa-related antibiotics which are used to treat bacterial and some fungal infections. The first sulfa drug was prontosil. It was discovered by the German physician and chemist Gerhard Domagk in 1935. The sulfa family of drugs includes sulfadiazine, sulfamethizole (brand name: Thiosulfil Forte), sulfamethoxazole (Gantanol), sulfasalazine (Azulfidine), sulfisoxazole […]