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 […]

1. Literally, relating to a maternal aunt. 2. Figuratively, suggestive of an aunt on either side of the family. 3 In medical genetics, pertaining to an aunt. An materteral relationship is the genetic relationship between aunts and their nieces and nephews. Materteral is synonymous with materterine. From the Latin matertera meaning maternal aunt, from mater […]

Zemplar. In 1998 paricalcitol was approved by the FDA for the treatment of secondary hyperparathyroidism due to chronic renal failure. It causes less elevation of calcium than calcitriol, another vitamin D analogue and is associated with a lower mortality rate than calcitriol in patients on long-term dialysis.

Hiatal hernias are categorized as being either para-esophageal or sliding. Para-esophageal hernias are hernias in which the gastro- esophageal junction stays where it belongs (attached at the level of the diaphragm), but part of the stomach passes or bulges into the chest beside the esophagus. The para- esophageal hernias themselves remain in the chest at […]

Chloroprene: A possible carcinogen (cancer-causing agent) primarily used in the production of the elastomer polychloroprene (neoprene). The US government in 2000 classified chloroprene as “reasonably anticipated to be a human carcinogen.” In laboratory animal studies of chloroprene, cancer was observed in multiple organs of multiple species following long-term inhalation exposures.

Choana: An opening at the back of the nasal passage (there is a left and a right side) that empties into the space behind the nose called the nasopharynx, where the adenoids and eustachian tube are. The passage way continues down into the back of the mouth and into the throat.