Webster's New World Medical Dictionary

erythroblastosis
See 
hemolytic disease of the
newborn.
erythrocyanosis
Discoloration on the legs that
has a bluish or purple hue.
erythrocyte
See 
red blood cell.
erythrocyte membrane protein band 4.1
See
elliptocytosis.
erythroleukemia
A form of acute myeloid
leukemia (AML) that involves the cells that give rise
to the erythrocytes (red blood cells). In ery-
throleukemia, the body produces large numbers of
abnormal, immature red blood cells.
erythromycin
An antibiotic that is commonly
prescribed to treat bacterial infection. Erythromycin
prevents bacteria from producing proteins and
interferes with bacterial growth and multiplication.
See also 
macrolide antibiotic.
erythroplakia
An abnormal reddened patch
with a velvety surface that is found in the mouth.
Erythroplakia carries an increased risk for becom-
ing a cancer in the oral cavity. Treatment methods
include observation, topical ointments, and surgical
techniques including laser surgery.
erythropoietin
A hormone that is produced by
the kidney and promotes the formation of red blood
cells in the bone marrow. Abbreviated EPO. Human
EPO is a glycoprotein (a protein with an attached
sugar) that has a molecular weight of 34,000. The
kidney cells that make EPO are specialized and are
sensitive to low oxygen levels in the blood that
comes into the kidney. These cells release EPO
when the blood oxygen level is low. EPO stimulates
the bone marrow to produce more red blood cells,
which in turn increases the oxygen-carrying capac-
ity of the blood. EPO is produced not only in the kid-
ney but also, to a lesser extent, in the liver. The
amount of EPO in the blood can indicate bone mar-
row disorders or kidney disease. Normal levels of
EPO are 0 to 19 milliunits per milliliter (mU/ml).
Elevated levels can be seen in polycythemia rubra
vera, a disorder characterized by an excess of red
blood cells. Lower-than-normal values of EPO are
seen in chronic renal failure. Using recombinant
DNA technology, EPO has been synthetically pro-
duced for use in persons with anemia due to kidney
failure and other conditions. It has been misused as
a performance-enhancing drug in endurance ath-
letes, reportedly including cyclists, long-distance
runners, speed skaters, and cross-country skiers. As
such, EPO is thought to be especially dangerous,
perhaps because dehydration can further increase
the thickness of the blood, increasing the risk for
heart attacks and strokes. See also 
EPO test.