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 […]

The use of X-rays of known wavelength to learn the structure of any crystalline material. Put otherwise, X-ray crystallography is a technology by which the locations of atoms in any crystal can be precisely mapped by looking at the image of the crystal under an X-ray beam. The crystal is placed in the beam of […]

Analbuminemia: 1. Properly, an absence of albumin from the blood. 2. More loosely, a low level of albumin in the blood. Synonymous in this usage with hypoalbuminemia.

Chemoprophylaxis: The use of a chemical agent to prevent the development of a disease. See: Chemoprevention.

A drug that calms a patient, easing agitation and permitting sleep. Sedatives generally work by modulating signals within the central nervous system. If sedatives are misused or accidentally combined, as in the case of combining prescription sedatives with alcohol, they can dangerously depress important signals that are needed to maintain heart and lung function. Most […]

herpes simplex, herpes zoster, cytomegalovirus, Epstein-Barr virus, enteroviruses (poliomyelitis, Coxsackie virus, echovirus), human T-cell leukemia virus, human immunodeficiency virus (HIV), influenza, measles, and rabies, Mycoplasma pneumoniae, Lyme borreliosis, syphilis, and tuberculosis. There is no specific treatment for transverse myelitis. The prognosis for complete recovery from transverse myelitis is generally not good. Although recovery usually begins […]