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 […]

Oscillating vision. Swinging vision. In oscillopsia, objects seem to swing, move back and forth, jerk, or wiggle. A classical language hybrid derived from the Latin oscillo, to swing, + the Greek opsis, vision.

Pain that results from irritation of the sciatic nerve and typically radiates from the buttock to the back of the thigh. Although sciatica can result from a herniated disc pressing directly on the nerve, any cause of irritation or inflammation of this nerve can reproduce the painful symptoms of sciatica. Diagnosis is made via observation […]

Deer mouse: A deceptively cute rodent capable of carrying the types of hantavirus that cause HPS (hantavirus pulmonary syndrome) in the US. The deer mouse has big eyes and big ears. Its head and body are normally about 2 to 3 inches long, and the tail adds another 2 to 3 inches in length. It […]

Anesthesia: Loss of feeling or awareness, as when an anesthetic is administered before surgery.

A disorder characterized by painless symmetrical diffuse deposits of fat beneath the skin of the neck, upper trunk, arms and legs. The condition is thought to be genetic although its exact mode of inheritance is uncertain. It may be a mitochondrial DNA disease. It frequently appears in association with alcoholic liver disease, macrocytic anemia (“low […]