GALLIUM
G
gallium
A metallic element whose radioactive
form is used in
radionuclide scanning
(a
technique using a tiny amount of a
radioactive substance to obtain images
of internal organs). Gallium is injected
into the bloodstream before a scan in
order to reveal areas of inflammation,
such as those that occur in cancers,
abscesses
,
osteomyelitis
,
and
sarcoidosis
.
gallstone ileus
See
ileus, gallstone
.
gallstones
Lumps of solid matter found in the
gallbladder
(the
sac
under
the
liver
where bile is stored) or in the
bile ducts
(which connect the gallbladder and liver
to the duodenum). Most gallstones are
made of
cholesterol
and bile pigments
from the breakdown of red blood cells.
CAUSES AND INCIDENCE
Gallstones develop due to a disturbance
in the chemical composition of
bile
.
They are rare in childhood and become
increasingly common with age. Women
are affected more than men. Risk factors
for developing gallstones include a high-
fat diet and being overweight.
SYMPTOMS
Most gallstones cause no symptoms. Any
symptoms often begin when a stone
lodges in the gallbladder outlet. This
problem causes
biliary colic
(intense pain
in the upper right area of the abdomen
or between the shoulderblades), nausea,
and sometimes indigestion and flatu-
lence.
Possible
complications
include
cholecystitis
(inflammation of the gall-
bladder) and
bile duct obstruction
.
DIAGNOSIS AND TREATMENT
Gallstones
are
usually
diagnosed
by
ultrasound scanning
,
X-ray
oral
chole-
cystography
,
or
cholangiography
.
Stones that are not causing symptoms
are usually left alone. In other cases, the
gallbladder and stones may be surgically
removed by
cholecystectomy
.
Ultrasonic
shock waves (see
lithotripsy
)
are some-
times used to shatter gallstones; the
fragments pass into the intestines and
cause no further problems. Drugs such
as
ursodeoxycholic acid
can dissolve some
gallstones if taken over several months,
but further stones may form once the
treatment is stopped.
gambling, pathological
A chronic inability to resist impulses to
gamble, resulting in personal, social,
and/or financial problems.
gamete
A sex cell. Gametes are found in the
reproductive systems of adults:
sperm
are formed in the
testes
in males, and an
ovum
(egg cell) is released approximate-
ly every month from the
ovaries
in
females. Sperm and ova come together
during
fertilization
to create offspring.
(See also
meiosis.)
gamete intrafallopian
transfer (GIFT)
A technique for assisting
conception
(see
infertility
) in women. It can only be used
if a woman has functioning
fallopian
tubes.
In GIFT, ova (eggs) are removed
from the woman’s
ovary
during
laparo-
scopy
(viewing of the interior of the
abdomen) and mixed with
sperm
in the
laboratory. The mixed eggs and sperm
are introduced into one of the fallopian
tubes, where
fertilization
takes place. A
fertilized egg may then become im -
planted in the
uterus
.
Gamgee tissue
The brand name for a material consist-
ing of a thick layer of highly absorbent
cotton wool enclosed in gauze. Gamgee
tissue may be used for padding and
compression of soft-tissue injuries, but
may also be used on open wounds,
such as
ulcers,
to aid the healing process
by applying compression and soaking
up body fluids.
gamma aminobutyric acid
See
GABA.
gamma camera
A piece of equipment used to generate
diagnostic images in
radionuclide scan-
ning.
A tiny amount of a radioactive
substance is introduced into the body
(usually by injection) and taken up by
the tissues to be examined. The gamma
camera detects radiation emitted by the
material and
displays
its
pattern
of
distribution as an image on a monitor.
gamma-globulin
A
substance
that
contains
antibodies
against a specific infection. Injections of
gamma-globulins
provide
temporary
protection against diseases such as
chick-
enpox
and
tetanus.
(See
immunization;
immunoglobulin injections.)
gamolenic acid
An essential
fatty acid
found in evening
primrose oil and starflower
(borage)
oil. Gamolenic acid may be taken for
premenstrual syndrome
and
eczema.
Very
large doses may cause abdominal pain
and loose stools.
ganciclovir
An
antiviral drug
that is used to treat
severe
cytomegalovirus
infection. Such a
condition occurs in those people whose
immune system
is impaired or suppres-
sed because they have
AIDS,
they are
taking
immunosuppressant drugs,
or have
had an organ
transplantation
.
Ganciclovir is toxic and produces a
range of side effects, including nausea;
diarrhoea; abdominal pain; weakness;
and suppression of blood cell formation
in the bone marrow. For this reason, it
is used only when the benefits are likely
to outweigh the risks.
ganglia
The plural form of
ganglion
.
ganglion
A group of
nerve
cells that have a com-
mon function; for example, the
basal
ganglia
in the brain are concerned with
the control of muscular movements.
The term is also used to describe a
fluid-filled swelling associated with the
sheath of a
tendon.
A ganglion may dis-
appear spontaneously; if necessary, it
may be drained or removed surgically.
gangrene
Death of tissue, usually caused by loss
of the blood supply.
Gangrene
may
affect a small area of skin or a large por-
tion of a limb.
SYMPTOMS AND TYPES
Pain is felt as the tissues are dying, but
once
dead they become
numb. The
affected tissue turns black. There are
two types of gangrene: dry and wet.
In dry gangrene, the tissue dies as it
has no blood supply. The gangrene does
not spread. Dry gangrene may be caused
by
arteriosclerosis,
diabetes
mellitus,
thrombosis,
frostbite, or an
embolism.
Gangrene of the foot
This shows a gangrenous foot, with areas of dead
tissue and blackening of the skin on the big toe.
330
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