Webster's New World Medical Dictionary

U
Uracil, one of the nucleotide bases in RNA.
UA
Urinalysis.
UAL
Ultrasonic-assisted liposuction. See 
liposuc-
tion, ultrasonic-assisted.
UBT
Urea breath test.
UDP-glucuronosyltransferase
A liver enzyme
that is essential to the disposal of bilirubin, the
chemical that results from the normal breakdown of
hemoglobin from red blood cells. An abnormality of
UDP-glucuronosyltransferase results in a condition
called Gilbert syndrome. See also 
Gilbert syndrome.
ulcer
A lesion that is eroding away the skin or
mucous membrane. Ulcers can have various causes,
depending on their location. Ulcers on the skin are
usually due to irritation, as in the case of bedsores,
and may become inflamed and/or infected as they
grow. Ulcers in the gastrointestinal tract were once
attributed to stress, but most are now believed to be
due to infection with the bacterium Helicobacter
pylori. GI ulcers, however, are often made worse by
stress, smoking, and other noninfectious factors.
ulcer, apthous
See 
canker sore.
ulcer, duodenal
An ulcer in the lining of the
duodenum, the first portion of the small intestine.
See also 
ulcer; ulcer, peptic.
ulcer, esophageal
An ulcer in the lining of the
esophagus that is corroded by the acidic digestive
juices secreted by the stomach cells. See also 
ulcer;
ulcer, peptic.
ulcer, gastric
An ulcer in the lining of the stom-
ach that is corroded by the acidic digestive juices
secreted by the stomach cells. See also 
ulcer; ulcer,
peptic.
ulcer, peptic
An ulcer in the lining of the stom-
ach, duodenum, or esophagus. Peptic ulcers affect
millions of people in the US yearly. Ulcer formation
is related to Helicobacter pylori bacteria in the
stomach, use of anti-inflammatory medications, and
cigarette smoking. Peptic ulcer pain may not corre-
late with the presence or severity of ulceration.
Complications of peptic ulcers include bleeding,
perforation, and blockage of the stomach (gastric
obstruction). Diagnosis is made via barium X-ray or
endoscopy. Treatment involves use of antibiotics to
eradicate H. pylori, elimination of risk factors, and
prevention of complications.
ulcer, stasis
A skin ulcer that develops in an area
in which the circulation is sluggish and the return of
venous blood toward the heart is poor. A common
location for stasis ulcers is on the ankles. Stasis
refers to a stoppage or slowdown in the flow of
blood (or other body fluid, such as lymph).