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 […]

(1906-93) Pioneering researcher on viruses and viral diseases who developed the oral live-virus vaccine against polio. Sabin’s vaccine came to be preferred over the alternative killed-virus vaccine developed by his bitter rival Dr. Jonas Salk. The Sabin vaccine contains harmless attenuated polio virus. Dr. Sabin first showed that polio virus could grow in human nerve […]

Drugs, teratogenic: A teratogen is an agent that can disturb the development of the embryo or fetus. Teratogens halt the pregnancy or produce a congenital malformation (a birth defect). Classes of teratogens include radiation, maternal infections, chemicals, and drugs. Drugs that are capable of acting as teratogens include: ACE (angiotensin converting enzyme) inhibitors such as: […]

A popular and pejorative, term for nasal mucus (mucus produced in the nose).

Abnormally dry skin. Can be caused by a dry climate, winter weather, severe deficiency of vitamin A, systemic illness, overexposure to sunlight, or medication. The skin loses moisture. It may crack and peel. Or it may become irritated, inflamed, and itch. Bathing frequently, especially with soaps, can contribute to dry skin. With dry skin, it […]

ELA2: The gene encoding the enzyme elastase 2 (neutrophilic elastase). Mutations in ELA2 cause cyclic neutropenia. See: Elastase 2.