GENTAMICIN
alleles
(any of various forms of a
gene
)
at a specific location within a
chromo-
some
;
the genetic information carried
by alleles determines a particular char-
acteristic of that organism.
gentamicin
An
antibacterial drug
given by injection
to treat serious infections such as
menin-
gitis
and
septicaemia
(blood poisoning).
Gentamicin can result in damage to the
kidneys or the inner ear if the dosage is
not carefully controlled.
The drug is also used in various eye
and ear-drops but is unlikely to cause
serious side effects when taken in these
types of preparation.
gentian violet
A purple dye used to make
bacteria
vis-
ible under a microscope. Gentian violet
was also formerly used as an
antiseptic
.
genu valgum
The medical term for
knock-knee
.
genu varum
The medical term for
bowleg
.
geriatric medicine
The medical speciality concerned with
the care of elderly people, also known
as “ care for the elderly” . This group
require specialist medical care because
they respond to illness and treatment in
a different way from younger people.
Physical and mental
decline
due to
aging
can mean that illnesses are more
severe in older people, and people may
have two or more diseases at once. In
addition, the liver and kidneys become
less
efficient at
breaking
down and
excreting drugs, so drug dosages for
elderly people must be carefully con-
trolled to avoid dangerous side effects.
Geriatric medicine relies on an inte-
grated
team
of health-care
workers,
including a doctor (or a specialist called
a geriatrician), nurse, physiotherapist,
and occupational therapist. This team
helps older people to maintain inde-
pendence and health, and to cope after
illness or injury. (See also
rehabilitation
. )
germ
The popular term used to describe any
microorganism that causes disease, such
as
viruses
and
bacteria
.
German measles
The common name for the viral infec-
tion
rubella
.
germ cell
An embryonic
cell
with the potential to
develop into a
spermatozoon
or
ovum
.
The
term
also
describes
a
gamete
(mature sex cell)
or any cell that is
undergoing gametogenesis (the process
by w hich gametes are formed).
germ cell tumour
A growth comprised of immature
sperm
cells in the male
testis
or of immature
egg cells (see
ovum
)
in the female
ovary
.
A
seminoma
is one type of germ cell
tumour (see
testis, cancer of
) .
gerontology
The study of developmental, biological,
medical, psychological, and sociological
aging
.
(See also
geriatric medicine
. )
Gerstmann’s syndrome
A
neurological
disorder
involving
a
w riting
disability
such
as
agraphia
,
together with the inability to under-
stand
mathematical
calculations,
to
distinguish right from left, and to iden-
tify the fingers
(a type of
agnosia
) .
Many sufferers also experience
aphasia
(complete loss of language skills). The
syndrome may occur after a
stroke
or
damage to the left parietal lobe of the
brain
,
but the precise cause is unknown.
Gerstmann-Straussler syndrome
A rare, inherited type of human
spongi-
form encephalopathy
,
the group of de-
generative brain disorders to w hich
Creutzfeldt-Jakob disease belongs. Gerst-
mann-Straussler syndrome is believed
to be caused by infection with a
prion
(slow virus).
The disease is characterized by
ataxia
(loss of balance) and
dementia
and is
not usually evident before early adult-
hood. It progresses more slowly than
Creutzfeldt-Jakob disease, but there is
no cure, and death usually occurs w ith-
in three to five years.
Gestalt theory
A school of
psychology
that emphasizes
the viewing of personal experiences as a
whole rather than breaking them down
into collections of stimuli and respon-
ses. Gestalt therapy aims to increase
self-awareness by looking at all aspects
of a person in his or her environment.
gestation
The period that lasts approximately nine
months
between
conception
and
the
birth of a human baby; it is the time
during w hich the infant develops in the
uterus
.
(See
also
embryo
;
fertilization;
fetus
;
pregnancy
.)
gestational diabetes
Diabetes mellitus
that develops during
pregnancy,
usually
clearing
up
after
delivery (see
diabetic pregnancy
) .
gestodene
A
progestogen drug
that is used with the
oestrogen drug
ethinylestradiol
in low-
strength
combined
oral contraceptives
.
Gestodene is reported to carry a slightly
increased risk of venous
thromboembol-
ism
(the blockage of a blood vessel by a
fragment of a blood clot) in compari-
son with older drugs.
Ghon’s tubercle
An abnormal area in the lung, also
known as a Ghon’s focus, that is pro-
duced by infection with
tuberculosis
in a
person who has not previously been
exposed to the disease. Often, a Ghon’s
tubercle heals without causing symp-
toms, but in some cases it may result in
tuberculosis that spreads via the
lym-
phatic system
,
in the bloodstream, or in
the air sacs of the lungs. A healed tuber-
cle may become calcified, and may be
discovered during a routine
chest X-ray
.
Gianotti-Crosti syndrome
A characteristic, harmless response of
the
skin
to
certain viral
infections,
including
hepatitis B
infection,
Epstein
Barr virus
(see
mononucleosis, infectious
),
and
coxsackievirus
.
In this condition, a
papular (lumpy) rash develops on the
face, buttocks, and limbs and lasts for
several weeks. The
condition mainly
affects children between the ages of six
months and twelve years.
SYMPTOMS AND SIGNS
There may be no noticeable symptoms.
Alternatively, there may be a m ild tem-
perature,
and swelling of the
lymph
nodes
in the armpits and groin that per-
sists for some months. The liver may
become enlarged.
DIAGNOSIS AND TREATMENT
Blood tests
and
liver function tests
are car-
ried out to investigate liver function and
detect possible causative viruses. There
is no specific treatment, but a mild,
topical
corticosteroid
cream may be pre-
scribed for itching. The rash usually
fades in two to eight weeks.
giant cell arteritis
An alternative name for
temporal arteritis
.
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