Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «T»:
Transformation, genetic: A process by which the genetic material carried by an individual cell is altered by the incorporation of foreign (exogenous) DNA into its genome....
Transforming growth factor
Transforming growth factor:
(TGF) One of several proteins secreted by transformed cells that can stimulate the growth of normal cells. Transforming growth factor alpha (TGF alpha or TGF-A) binds the epidermal growth factor receptor (EGFR) and stimulates the growth of endothelial cells (cells that l...
Transforming principle: Name originally given to DNA. In 1944 Avery, MacLeod, and McCarty published their discovery that the transforming principle was DNA.
In the early 1940s Oswald T. Avery and Maclyn McCarty, a colleague at the Rockefeller Institute Hospital, began concentrating on the problem of...
Transfusion: The transfer of blood or blood products
from one person (the donor) into another person (the recipient's)
bloodstream. In most situations, this is done as a lifesaving
maneuver to replace blood cells or blood products lost through severe
bleeding. Transfusion of your own blood (autolo...
Transfusion medicine: Blood transfusion and blood conservation are the complementary activities that constitute the clinical arena of transfusion medicine.
Blood transfusion is the transfer of blood or blood products from one person (the donor) into another person's (the recipient's) bloodstream. In...
Transgenic: Having genetic
material (DNA) from another species. This term can be applied to an organism that has genes from another organism. It is understood that the foreign genes are in the transgenic animal's germ-cell DNA and so can be transmitted from one generation to the next....
Transient global amnesia
Transient global amnesia: A passing episode of short-term memory loss without other signs or symptoms of neurological impairment. In transient global amnesia (TGA) the individual does not lose consciousness but does lose the ability to form new lasting memories. Motor function is not affected. The i...
Transient insomnia: See Insomnia, transient....
Transient ischemic attack (TIA, Mini-Stroke)
Transient ischemic attack (TIA, Mini-Stroke): A neurological event with the signs and symptoms of a stroke, but which go away within a short period of time. Also called a mini-stroke, a TIA is due to a temporary lack of adequate blood and oxygen (ischemia) to the brain. This is often caused by the n...
Transillumination: The passing of a strong beam of light through a part of the body for medical inspection. A method of examination by the passage of light through tissues or a body cavity.
A common use of transillumination is in infancy. The infant's skull should normally not transilluminate (let a...
Transition, menopause: A woman can usually tell if she is approaching menopause because her menstrual periods starts changing. The medical terms used to describe this time are the "menopause transition" and "perimenopause".
The changes of the menopause transition (perimenopause) begin about 6 years...
Transitional cell carcinoma
Transitional cell carcinoma: A type of cancer that develops in the lining of the renal pelvis, ureter or bladder....
Transjugular intrahepatic portosystemic shunt
Transjugular intrahepatic portosystemic shunt: A shunt that allows blood from the portal circulation (that supplies the liver) to flow into the systemic (general) circulation.
Transjugular intrahepatic portosystemic shunt involves catheterization of a hepatic (liver) vein by the transjugular approa...
Translation: To go from RNA to protein, translation is
needed. Translation is the process by which the genetic code carried by messenger RNA
(mRNA) directs the production of proteins from amino acids. ...
Translocation 11 childhood leukemia
Translocation 11 childhood leukemia: A new type of childhood leukemia in which a piece of chromosome 11 has been translocated (broken off and attached itself to another chromosome). Children with this type of leukemia have a particularly poor prognosis (outlook). They do not respond at all well to t...