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 type of white blood cell that is of key importance to the immune system and is at the core of adaptive immunity, the system that tailors the body’s immune response to specific pathogens. The T cells are like soldiers who search out and destroy the targeted invaders. Immature T cells (termed T-stem cells) migrate […]

Balanitis, circinate: A form of skin inflammation around the penis in males with Reiter’s syndrome. The skin around the shaft and tip (glans) penis can become inflamed and scale. This inflammation around the penis can be helped by cortisone creams (such as TOPICORT). Reiter’s syndrome is a systemic rheumatic disease, systemic since it can affect […]

Antimicrobial agent: A general term for drugs, chemicals, or other substances that either kill or slow the growth of microbes. Among the antimicrobial agents are antibacterial drugs, antiviral agents, antifungal agents, and antiparisitic drugs.

Referring to the proliferation of the bone marrow cells that give rise to red blood cells, granulocytes (a type of white blood cells), and/or platelets (crucial to blood clotting). The term myeloproliferative is in contrast to lymphoproliferative which refers to proliferation of lymphoid cells and reticuloendothelial cells such as macrophages. Both terms — myeloproliferative and […]

A form of phosphoric acid. Calcium phosphate makes bones and teeth hard.