CLOSTRIDIUM
C
Clostridium
Any of a group of rod-shaped
bacteria
.
Clostridia are found in soil and in the
gastrointestinal tracts of humans and
animals. They produce powerful toxins
and are responsible for potentially life-
threatening diseases such as
botulism
,
tetanus
,
and
gangrene
.
clot
See
blood clotting
.
clotrimazole
An
antifungal drug
that is used to treat
yeast and fungal infections, especially
c
andidiasis.
clotting factor
A circulating protein that is activated
during the
blood clotting
process. There
are a number of clotting factors, w hich
are involved in a complex series of
chemical reactions leading to the for-
mation of a blood clot.
clotting time
The time taken for blood to coagulate,
w hich is
measured in tests by the
observation of a blood sample under
laboratory conditions. (See also
blood-
clotting tests
. )
cloudy urine
An abnormality in the appearance of
urine
,
w hich may be caused by a
urinary
tract infection
or the presence of salts.
(See also
urine, abnormal
. )
clove oil
An oil distilled from the dried flower-
buds of E
ugenia
cartophtllata
that is
used mainly as a flavouring in pharma-
ceuticals. Clove oil is sometimes used
to relieve abdominal pain due to
flatu-
lence
and as a remedy for toothache.
cloxacillin
A penicillin-type antibiotic drug used
to treat infections with staphylococcal
bacteria (see
penicillin drugs
) .
clozapine
A type of
antipsychotic drug
.
Clozapine
is used to treat
schizophrenia
in patients
w ho have not responded well to other
forms of treatment, or in those who
have experienced severe side effects
from more conventional drugs. A per-
son taking clozapine needs to have
regular blood tests because the drug
may cause a serious decrease in the
number of
white blood cells
.
Clozaril
A brand name for
clozapine
.
clubbing
Thickening and broadening of the fin-
gertips and ends of the toes, w hich is
usually
accompanied
by
increased
curving of the nails. Clubbing is associ-
ated w ith certain chronic lung diseases,
such as
lung cancer
,
bronchiectasis
,
and
fibrosing
alveolitis
;
with some
heart
abnormalities;
and,
rarely,
with
the
inflammatory
bowel
diseases
Crohn’s
disease
and
ulcerative colitis
.
club-foot
A deformity of the foot that is present
from birth (see
talipes
) .
clumping
The common name for agglutination, a
process in w hich tiny particles that the
body identifies as foreign (see
antigen
) ,
such as the proteins on the surfaces of
bacteria or foreign red blood cells, stick
together to form visible masses. This
process is an immune system reaction
caused by antibodies (proteins manu-
factured by the immune system; see
antibody
)
called agglutinins. Particles of
a particular antigen w ill only clump
together in the presence of the specific
agglutinin to that antigen.
Looking for clumping can be used as
a means of determining people’s blood
groups. In blood typing, samples of a
person’s blood are m ixed with anti-
bodies against the blood types A and B
to see if clum ping occurs with either
of these antibodies, neither, or both
(see
blood groups
) .
In
cross-matching
,
a
sample of a person’s blood is mixed
w ith a sample of blood from a possible
donor; if the red blood cells clump
together, it shows that the two samples
of blood are of incompatible types. In
addition,
bacteria
can
be
identified
using samples that contain agglutinins
to specific bacteria (as, for example, in
the
latex agglutination test
) .
cluster headaches
Brief but severe headaches that recur up
to several times a day over a period of a
few days or weeks. Cluster headaches
tend to affect one side of the head or
face, often in a characteristic pattern,
and may also cause pain and watering
of the eye. The cause is uncertain, but
they may be due to dilation of blood
vessels in the brain, as in
migraine
.
Beta-
blocker drugs
may be given in order to
lessen the dilation of the blood vessels
and reduce the severity and frequency
of cluster headaches.
CMV
The abbreviation for
cytomegalovirus
,
w hich is a type of
herpes
virus.
CNS
The abbreviation for
central nervous sys-
tem
(the brain and spinal cord).
CNS stimulants
Drugs that increase mental alertness
(see
stimulant drugs
) .
coagulation, blood
The main mechanism by w hich blood
clots are formed. Coagulation involves a
complex
series
of reactions
in
the
blood
plasma
(see
blood clotting
) .
coal tar
A thick, black, sticky substance that is
distilled from coal. Coal tar is a com-
mon ingredient in many
ointments
and m edicinal shampoos that are pre-
scribed
for
certain
skin
and
scalp
disorders, such as
psoriasis
and some
types of
dermatitis
and
eczema
.
co-amilofruse
A combined preparation that contains
the
diuretic
drugs
amiloride
and
furosemide
(frusemide).
co-amoxiclav
A
penicillin drug
containing a mixture of
amoxicillin
and
clavulanic acid
.
It is a
more powerful antibiotic than amoxi-
cillin
alone,
so
it
is
used
to
treat
infections caused by strains of bacteria
that are resistant to am oxicillin.
coarctation of the aorta
A
congenital
heart defect of unknown
cause, in w hich there is narrowing in a
section of the
aorta
that supplies blood
to the lower body and legs. To compen-
sate for this problem the heart has to
work
harder
than
normal,
thereby
causing
hypertension
(high blood pres-
sure) in the upper part of the body.
SYMPTOMS
Symptoms of coarctation of the aorta
usually appear in early childhood. They
include headache, weakness after exer-
cise, cold legs, and, rarely, breathing
difficulty and swelling of the legs due
to
heart failure
.
Associated abnormalities
include a heart
murmur,
weak or absent
pulse in the groin, lack of synchroniza-
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