Webster's New World Medical Dictionary

amenorrhea
See 
menstruation, cessation of.
amenorrhea, physiologic
The cessation of
menstruation for completely normal reasons. The
lack of menstruation during pregnancy and lacta-
tion are forms of physiologic amenorrhea.
amenorrhea, primary
The failure of menstrua-
tion to occur at puberty.
amenorrhea, secondary
The cessation of men-
struation for abnormal reasons. Causes include
anorexia nervosa, disease of the female reproduc-
tive tract, and overexercise. Secondary amenorrhea
can also be caused by certain medications, notably
the birth control medication medroxyprogesterone
(brand name: Depo-Provera); in this case, amenor-
rhea is an expected effect.
American Type Culture Collection
The world’s
premier biological culture repository, and a key
resource for medical research.
AMI
Acute myocardial infarction.
amine
A chemical compound containing nitro-
gen. Amines are derived from ammonia.
amino acid
One of the 20 building blocks from
which proteins are assembled. Isoleucine, leucine,
lysine, phenylalanine, threonine, tryptophan, and
valine are deemed “essential” amino acids because
the human body cannot make them and they must
be obtained in the diet. Amino acids are sometimes
taken orally in supplement form.
amino acid screen
A screening blood or urine
test that returns information about the levels of
amino acids. An amino acid screen is useful in diag-
nosing certain conditions, including the inborn
errors of amino acid metabolisms such as
phenylketonuria (PKU).
aminotransferase
An enzyme that catalyzes the
transfer of an amino group from a donor molecule
to a recipient molecule. The donor molecule is usu-
ally an amino acid and the recipient molecule is
usually an alpha-2 keto acid. Two of the best-known
enzymes in this class are serum glutamic
oxaloacetic transaminase (SGOT) and serum glu-
tamic pyruvic transaminase (SGPT), both of which
are normally found primarily in cells in the liver and
heart.
amitriptyline
A tricyclic antidepressant drug
(brand name: Elavil) prescribed to treat depres-
sion, chronic pain, migraines, eating disorders, and
a wide variety of other conditions. See also 
tricyclic
antidepressant.