A twin detected in early pregnancy that is miscarried, frequently by resorption, without clinical signs or symptoms. The surviving twin continues to grow and develop.
A vaccine against hepatitis A made of killed hepatitis A virus to stimulate the body’s immune system to produce antibodies against the hepatitis A virus.
- Varco, Richard L.
Innovative American surgeon (1912-2004) who helped perform the first successful open heart operation. On Sept. 2, 1952 at the University of Minnesota. Dr. Varco’s team, led by Dr. C. Walton Lillehei and Dr. F. John Lewis, cut off the flow of blood to the heart after lowering the patient’s body temperature to protect her brain. […]
- Variant Creutzfeldt-Jakob disease
Abbreviated vCJD. A human disease thought due to the same infectious agent as bovine spongiform encephalopathy (BSE), or mad cow disease. Both the human and bovine disorders are invariably fatal brain diseases with unusually long incubation periods measured in years, and are caused by an unconventional transmissible agent, a prion, resulting in the deposition of […]
- Variant angina
Chest pain due to coronary artery spasm, a sudden constriction of a coronary artery (one of the vessels that supply the heart muscle with blood rich in oxygen) depriving the heart muscle (myocardium) of blood and oxygen. This is also called Prinzmetal angina. Coronary artery spasm can be triggered by emotional stress, medicines, street drugs […]
- Variation, observer
Failure by the observer to measure accurately, resulting in error. Observer variation may be due to the observer’s missing a measurement, making an incorrect measurement, or misinterpreting data. Inter-observer variation is the amount of variation between the results obtained by two or more observers examining the same material. Intra-observer variation is the amount of variation […]