Webster's New World Medical Dictionary

particularly with two laterally paired parts, such as
a buttock.
chemical menopause
See 
menopause, chemi-
cal.
chemical reaction
A process in which one sub-
stance is transformed into another.
chemokine
One of a large group of proteins that
act as chemical messengers and were first found
attracting white blood cells to areas of inflamma-
tion. Chemokines are involved in several forms of
acute and chronic inflammation, infectious dis-
eases, and cancer.
chemokine receptor
A molecule that receives a
chemokine and associated proteins (chemokine
docks). Several chemokine receptors are essential
co-receptors for the HIV virus.
chemoprevention
The use of natural or labora-
tory-made substances to prevent cancer.
chemotherapy
Of or pertaining to treatment with
drugs to kill cancer cells. Most anticancer drugs are
injected into a vein, but some are given by mouth.
Chemotherapy is usually systemic treatment, mean-
ing that the drugs flow through the bloodstream to
nearly every part of the body. Chemotherapy is gen-
erally given in cycles: A treatment period is followed
by a recovery period, another treatment period, and
so on. The side effects of chemotherapy depend
mainly on the drugs and doses the patient receives.
Generally, anticancer drugs affect cells that divide
rapidly, including blood cells, which fight infection,
help the blood to clot, and carry oxygen to all parts
of the body. When white blood cells are affected by
anticancer drugs, patients are more likely to
develop infections. When red blood cells are
affected, they may have decreased energy. Cells that
line the digestive tract also divide rapidly, so
chemotherapy can cause loss of appetite, nausea
and vomiting, hair loss or thinning, and mouth
sores. For some patients, medicines can be pre-
scribed to help with side effects, especially with nau-
sea and vomiting. Usually these side effects
gradually go away during the recovery period or
after treatment stops. In some men and women,
chemotherapy drugs may result in temporary or
permanent loss of the ability to have children. For
men, sperm banking before treatment may be con-
sidered; women may choose to have eggs extracted
and stored. Women’s menstrual periods may stop,
and women may have hot flashes and vaginal dry-
ness due to induced menopause. In some cases,
bone marrow transplantation and peripheral stem-
cell support are used to replace bone marrow tissue
that has been destroyed by the effects of chemother-
apy. See also 
adjuvant chemotherapy; cancer.