Webster's New World Medical Dictionary

proctitis, ulcerative
Ulcerative colitis that is
limited to the rectum. See also 
colitis, ulcerative;
proctitis.
proctology
A medical specialty that deals with
disorders of the rectum and anus.
proctosigmoidoscopy
An examination of the
rectum and the lower part of the colon, using a thin,
lighted instrument called a sigmoidoscope.
product, gene
See 
gene product.
progeria
One of a group of rare genetic disor-
ders that causes premature aging in children. The
classic type of progeria is Hutchinson-Gilford prog-
eria syndrome, which is characterized by dwarfism,
baldness, pinched nose, small face and small jaw
relative to the head size, delayed tooth formation,
aged-looking skin, stiffness of joints, hip disloca-
tions, arteriosclerosis, and heart disease. These
children begin to display signs of accelerated aging
as early as 18 months of age and have a drastically
shortened lifespan. There is no cure or specific
treatment. Progeria is due to a mutation in the gene
for Lamin A protein. Werner syndrome has a later
onset and is sometimes called progeria of the adult.
See also 
Werner syndrome.
progesterone
A female hormone, the principal
hormone that prepares the uterus to receive and
sustain fertilized eggs.
progesterone receptor test
A lab test that is
used to determine whether breast cancer cells have
progesterone receptors. If the cells have proges-
terone receptors, they may depend on progesterone
for growth and usually respond to hormone therapy.
Breast cancer cells that do not have progesterone
receptors do not need the hormone progesterone
to grow and usually do not respond to hormone
therapy.
progestin
Any one of a group of steroid hor-
mones that have the effect of progesterone. See also
progesterone.
prognathism
An overly prominent jaw.
Prognathism may cause no problems or be associ-
ated with dental problems. Prognathism is charac-
teristic of some diseases, such as acromegaly.