Bma Illustrated Medical Dictionary

drink. If consciousness is impaired, for

example by a head injury or excess

alcohol intake, aspiration of the stom-

ach contents is common.

Aspiration biopsyis the removal of

cells or fluid for examination using a

needle and syringe. The procedure is

commonly used to obtain cells from a

fluid-filled cavity (such as a breast lump

or breast cyst). It is also used to obtain

cells from the bone marrow (see bone

marrow biopsy), or from internal organs,

when a fine needle is guided into the

site of the biopsy by CT scanningor

ultrasound scanning.

aspirinA nonopioid analgesic drug used

to treat disorders such as headache,

menstrual pain, and muscle discomfort.

Aspirin has an anti-inflammatoryaction

and is particularly useful for joint pain

in arthritis. It reduces fever and is inclu-

ded in some cold remedies. In small

doses, it reduces the stickiness of plate-

lets (blood particles involved in clotting).

This has led to its use in preventing

thrombosisin people at risk of develop-

ing strokeor myocardial infarctionand

as initial treatment of chest pain that may

be due to myocardial infarction. Aspirin

may also reduce the risk of colon cancer

and slow the progress of dementia.

Aspirin is not usually given to children

because there is a slight risk of Reye’s

syndrome(a rare brain and liver disorder)

developing. Aspirin may cause irritation

of the stomach lining, resulting in indi-

gestion or nausea. Prolonged use may

cause bleeding from the stomach due

to gastric erosionor peptic ulcer.

assayAnalysis or measurement of a

substance to determine its presence or

effects. Biological assays (bioassays)

measure the responses of an animal or

organ to particular substances. They can

be used to assess the effects of a drug

or to measure hormone levels. (See

also immunoassay; radioimmunoassay.)

assisted conceptionTreatment for in-

fertilityinvolving techniques that assist

the fertilization and implantation of eggs.

association areaOne of a number of

areas in the outer layer (cortex) of the

brainthat are concerned with higher

levels of mental activity. Association

areas interpret information received from

sensory areas and prompt appropriate

responses such as voluntary movement.

astereognosisAn inability to recognize

objects by touch when they are placed

in the hand, even though there is no

defect of sensation in the fingers or

difficulty in holding the object. Aster-

eognosis is either left- or right-sided;

tactile recognition is normal on the

other side. If both sides are affected,

the condition is called tactile agnosia.

Astereognosis and tactile agnosia are

caused by damage to parts of the cere-

brum(main brain mass) involved in

recognition by touch and may occur as

a result of a strokeor head injury.

astheniaAn outdated term for loss of

strength and energy (see weakness).

asthenia, neurocirculatorySee car-

diac neurosis.

asthmaA lung disease in which there is

intermittent narrowing of the bronchi

(airways), causing shortness of breath,

wheezing, and cough. The illness often

starts in childhood but can develop at

any age. At least 1 child in 7 suffers

from asthma, and the number affected

has increased dramatically in recent

years. Childhood asthma may be out-

grown in about half of all cases.

During an asthma attack, the muscle

in the walls of the airways contracts,

causing narrowing. The linings of the

airways also become swollen and in-

flamed, producing excess mucus that

can block the smaller airways.

In some people, an allergic response

triggers the airway changes. This aller-

gic type of asthma tends to occur in

ASPIRIN ASTHMA

A

Breast lump

Needle

Fat layer

ASPIRATION OF A BREAST LUMP

Syringe

draws cells

into needle

ASPIRATION

Normal

breast

tissue