Webster's New World Medical Dictionary

trophoblastic tumor, gestational
A tumor of
women, which develops in the tissues that are
formed following conception by the joining of
sperm and egg. Gestational trophoblastic tumors
start inside the uterus, the hollow, muscular, pear-
shaped organ where a baby grows. This type of
tumor occurs in women during the years when they
are able to have children. There are two types of
gestational trophoblastic tumors: hydatidiform mole
and choriocarcinoma.
tropical typhus
See 
typhus, scrub.
troponin test
A sensitive and specific blood test
used to determine whether a heart attack or damage
to the heart muscle has occurred. Troponin is a
complex of proteins found in skeletal and cardiac
muscle. Normally, very low levels of troponin are
present in the bloodstream. Heart attack and other
forms of damage to heart muscle release a certain
subtype of troponin into the bloodstream, where it
can be detected in the laboratory as a marker of
damage to the heart muscle.
true rib
See 
rib, true.
trunk bones
See 
bones of the trunk.
Trypanosoma cruzi
The microorganism that
causes Chagas disease. See also 
Chagas disease.
trypanosomiasis, American
See 
Chagas disease.
TSH
Thyroid stimulating hormone.
TSI
Thyroid stimulating immunoglobulin.
T-suppressor cell
A T cell that expresses the
CD8 transmembrane glycoprotein (CD8+ T cells).
T-suppressor cells close down the immune
response after invading organisms are destroyed. T-
suppressor cells are sensitive to high concentrations
of circulating lymphokine hormones, and they
release their own lymphokines after an immune
response has achieved its goal. This signals all other
immune system participants to cease their attack.
Some memory B-cells remain after this signal to
ward off a repeat attack by the invading organism.
Also known as T-8 cell. See also 
CD8; T cell; T lym-
phocyte, cytotoxic.