to measure hormone levels.
sectional images) of the skull may be
carried out to exclude the possibility of
a pituitary tumour and
of the abdomen and pelvis to
exclude a tumour of the adrenal glands
or ovaries. In some cases,
abdomen using a rigid or flexible view-
ing tube) may be required to inspect
Treatment of amenorrhoea, if found
to be necessary, is of the underlying
cause. (See also
A drug used, along with self-help mea-
sures, as an aid to stopping smoking.
Side effects include a dry mouth and
An alternative spelling for amphetamine
). (See also
oride is used in combination with loop
or thiazide diuretics in the treatment of
(high blood pressure) and
the oedema (fluid retention) that results
efficiency of the heart) or liver
A group of chemical compounds that
form the basic structural units of all
Each amino acid molecule consists
of amino and carboxyl groups of atoms
that are linked to a variable chain or
ring of carbon atoms.
Individual amino acid molecules are
bonds) to form short
chains of molecules called
Hundreds of polypeptides are, in turn,
linked together (also by peptide bonds)
to form a protein molecule. What dif-
ferentiates one protein from another is
the sequence of the amino acids.
There are 20 different amino acids
that make up all the proteins in the body.
Of these, 12 can be made by the body;
they are known as nonessential amino
acids because they do not need to be
obtained from the diet. The other eight,
the essential amino acids, cannot be
obtained in the diet.
The 20 amino acids that make up pro-
teins also occur free within cells and in
body fluids. In addition, there are more
than 200 other amino acids that are not
found in proteins but play an important
role in chemical reactions within cells.
used to treat certain
types of breast cancer, prostate cancer,
and some endocrine gland tumours.
Aminoglycosides, a type of
are given by injection and, because their
use can damage the inner ear or kidneys,
are generally reserved for the treatment
of serious infections. Important exam-
ples of these drugs are
which are also used topi-
cally for eye and ear infections.
that is used to treat
efficiency of the heart).
Aminophylline relieves breathing dif-
ficulty by widening the bronchi (the
main air passages to the lungs). It also
dilates (widens) blood vessels, thereby
improving blood flow from the heart,
and increases the production of urine.
Possible side effects of aminophylline
dizziness, and palpitations.
used in the treat-
ment of various types of
(irregular heart rate or rhythm). Long-
term use of amiodarone may result in
inflammation of the liver, thyroid prob-
lems, and damage to the eyes and lungs.
For this reason, amiodarone is usually
failed to be effective.
sedative effect. Amitriptyline is useful in
the treatment of
adverse effects include blurred vision,
dizziness, and drowsiness.
calcium channel blocker
drug that is
used to prevent
and to treat
(high blood pressure). Pos-
sible side effects of amlodipine include
headaches and dizziness.
A colourless, pungent gas that dissolves
in water to form ammonium hydrox-
ide, an alkaline solution (see
Ammonia consists of one nitrogen atom
linked to three hydrogen atoms. Ammo-
nia is produced in the body and helps
to maintain the
In severe liver damage, the capacity of
the liver to convert ammonia to
diminished. This leads to a high con-
centration of ammonia in the blood,
which is thought to be a major cause of
the impaired consciousness that occurs
Loss of the ability to memorize infor-
mation and/or recall information stored
Amnesic conditions affect
mainly long-term memory (where infor-
mation is retained indefinitely) rather
than short-term memory (where it is
only retained for seconds or minutes).
Many people with amnesia have a
memory gap that extends back for some
time before the onset of the disorder.
This condition, known as retrograde
amnesia, is principally a deficit of recall.
In the majority of cases, the memory
gap gradually shrinks over time.
Some people with amnesia are unable
to store new information in the period
following the onset of the illness. The
resultant gap in memory, known as
anterograde amnesia, extends from the
moment of onset of the amnesia to the
resumes (if at all). This memory gap is
Amnesia is the result of damage to, or
disease of, regions in the brain that are
concerned with memory function. Pos-
sible causes of such damage are
degenerative disorders such as
and other forms of
infections such as
thiamine deficiency in problem drink-
ers, which leads to
syndrome; brain tumours; strokes;
Amnesia can also
occur in some forms of psychiatric ill-
ness (in which there is no apparent
physical damage to the brain). Some
deterioration of memory is a common
A diagnostic procedure in which a small
using a syringe guided by