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 […]

A Chinese herb (also called sweet wormwood) from which is extracted the antimalarial agent artemisinin.

(PAP) An enzyme that is normally present only in small amounts in the blood, but that may be found at higher levels in some patients with prostate cancer, especially if the cancer has spread beyond the prostate. However, blood levels may also be elevated in patients who have certain benign prostate conditions or early stage […]

Acetoacetate: A molecular ion, CH3COCH2COO-, derived from acetoacetic acid.

Fewer sperm than usual. Azospermia, by contrast, means absolutely no sperm at all.

Oversensitivity of exposed roots of teeth to cold, hot, and sour foods because those roots are no longer protected by healthy gum and bone. Chronic gum disease contributes to toothache due to root sensitivities. The roots are the lower 2/3 of the teeth that are normally buried in bone. The bacterial toxins dissolve the bone […]