CYTOTOXIC DRUGS
CYTOLOGY METHODS
Cells for examination are obtained in several ways, depending
on the part ofthe body being investigated. Cells from body
surfaces may be collected by scraping or swabs; those from
internal structures may be obtained by biopsy or aspiration.
Improvements in collection techniques have made it possible
to take cellsfrom previouslyinaccessible sites. Ifa cytologist
can make a diagnosis from cells removed in these ways, the
patient may be spared an exploratory operation.
Cells from the cervix
The vagina is held open with a
speculum. Cells are scraped from the
surface ofthe cervixwith a spatula
(above) or a special brush.
Cells from the respiratory
tract or oesophagus
These cells are usuallyobtained by
using an
endoscope
fitted with a
small brush or suction tube.
Cells from body fluids
These cells are obtained either by
passing the fluid through a filter or
centrifugation (spinning the fluid
rapidly to separate outthe cells).
Aspiration biopsy
In this procedure, a veryfine
needle is passed into a suspected
tumour and a biopsysample of
cells is withdrawn.
C
Cystoscopy is used to inspect the blad-
der for
calculi
(stones),
bladder tumours
,
sites of bleeding and infection, and, in
children,
to
investigate
vesicoureteric
reflux
.
Cystoscopy is also used to take
urine samples from the
ureters
so that
doctors
can
look
for
infection
or
tumour cells.
Radiopaque
dye may be
injected into the
ureters
by
means
of the cystoscope
during the X-ray
procedure of retrograde pyelography
(see
urography
) .
Certain treatments can also be per-
formed through the cystoscope. These
include the removal of bladder tum-
ours or calculi and the insertion of
stents
(narrow tubes) into a ureter to
relieve an obstruction.
cystostomy
The surgical creation of a hole in the
bladder
.
Cystostomy is usually carried
out to drain
urine
in cases where the
introduction
of
a
catheter
(flexible
tube) would be either inadvisable or
simply impossible.
cystourethrography, micturating
An
X-ray
procedure that is used for
studying the
bladder
during the passing
of
urine.
Micturating
cystourethro-
graphy
is
most
commonly
used in
young
children
to
detect
abnormal
reflux
of urine (backflow of urine up
the ureters)
as the bladder empties.
(See
urodynamics
. )
-cyte
A suffix denoting a
cell
.
For example, a
leukocyte is a white blood cell; an
ery-
throcyte
is a red blood cell.
cyto-
A prefix that means “related to a
cell"
,
as in cytology, the study of cells.
cytokine
A protein released by cells in response
to the presence of harmful organisms
such as
viruses
.
Cytokines (such as
inter-
ferons
) bind to other cells, activating the
immune response (see
immune system
) .
cytology
The study of cells. The main use of
cytology is to detect abnormal cells; it
is widely used to screen for cancer (as
in the
cervical smear test
)
or to confirm a
diagnosis of cancer, and is increasingly
used in antenatal screening to detect
certain fetal abnormalities. Examination
of cells from body fluids helps doctors
to determine the cause of conditions
such as
pleural effusion
(fluid in the
pleural cavity around the lungs) and
ascites
(abnormal accumulation of fluid
in the abdominal cavity); for example
the tests can identify whether cancer or
infection is present.
Cells
are
collected by
procedures
such as scraping or fine-needle aspira-
tion
biopsy
.
For antenatal tests, cells
from the fluid that surrounds and cush-
ions the fetus in the uterus are obtained
by means of
amniocentesis
or
chorionic
villus sampling
.
cytomegalovirus
One of the most common
herpes
virus-
es. Cytomegalovirus
(CMV)
infection
causes infected cells to appear enlarged.
The virus may produce an illness that is
sim ilar to glandular fever (see
mono-
nucleosis
,
infectious
) ,
but usually there
are
no
symptoms.
Individuals
with
impaired im m unity are more seriously
infected. CMV in a pregnant woman
can cause birth defects and brain dam-
age in the baby.
cytopathology
The microscopic study of
cells
in health
and disease. (See also
cytology
. )
cytoplasm
The jellylike substance that contains
the internal structures of a
cell
.
Cyto-
plasm is 90 per cent water, but it also
also contains enzymes, amino acids,
and other chemicals that are required
for cell function.
cytotoxic drugs
A group of
anticancer drug
s that kill or
damage abnormal
cells
.
Cytotoxic drugs
may also damage or kill healthy cells,
especially those that multiply rapidly,
such as the cells in hair follicles or
those in the intestinal lining.
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