PLASMA PROTEINS
PLEURODYNIA
also called plasma exchange. Blood is
withdrawn from the body and the plas-
ma portion is removed by machines
called cell separators. The blood cells
are then mixed with a plasma substitute
and returned to the circulation. Plasma-
pheresis is used to remove damaging
antibodies
or antibody-antigen particles
from the circulation in
autoimmune dis-
orders
such as
myasthenia gravis
and
Goodpasture's syndrome.
plasma proteins Proteins present in
blood
plasma
, including
albumin
,
blood
clotting
proteins, and
immunoglobulins
.
plasminogen activator See
tissue plas-
minogen activator
.
plaster cast See
cast
.
plaster of Paris A white powder made
of a calcium compound that, when mixed
with water, produces a paste that can be
shaped before it sets. Plaster of Paris is
used for constructing
casts
and making
dental models (see
impression, dental
).
plastic surgery Any operation carried
out to repair or reconstruct skin and tis-
sue that has been damaged or lost, is
malformed, or has changed with aging.
Plastic surgery is often performed after
severe burns or injuries, cancer, or some
operations, such as
mastectomy
. Congen-
ital conditions that may require plastic
surgery include
cleft lip and palate
,
hypo-
spadias
, and imperforate anus (see
anus,
imperforate
). Techniques include
skin
grafts, skin flaps,
and
Z-plasty;
these may
be combined with
implants
or a
bone
graft
.
Microsurgery
allows transfer of
tissue to other parts of the body. (See
also
cosmetic surgery
.)
-plasty A suffix meaning shaping by
surgery; performing
plastic surgery
on.
platelet The smallest type of
blood cell
,
also called a
thrombocyte
. Platelets play
a major role in
blood clotting
.
platyhelminth A flat or ribbon-shaped
parasitic worm. (See
liver fluke, schisto-
somiasis
,
tapeworm
)
play therapy A method used in the
psychoanalysis
of young children, based
on the principle that all play has some
symbolic significance. Watching a child
at play helps a therapist diagnose the
source of the child's problems; the child
can then be helped to “act out” thoughts
and feelings that are causing anxiety.
plethora A florid, bright-red, flushed
complexion. It may be caused by dila-
tion of blood vessels, or, less commonly,
by
polycythaemia
.
plethysmography A way of estimating
the blood flow in vessels by measuring
changes in the size of a body part.
pleura A thin, 2-layered membrane, 1
layer covering the outside of the lungs
and the other lining the inside of the
chest cavity. Fluid between the layers
provides lubrication, allowing smooth
movement of the lungs during breathing.
PLEURA
Bronchus
Pleura
Trachea
Lung
pleural effusion An accumulation of
fluid between the layers of the
pleura
,
making breathing difficult. Pleural effu-
sion may be caused by
pneumonia
,
tuberculosis
,
heart failure
,
cancer
,
pul-
monary embolism
, or
mesothelioma
.
Diagnosis is confirmed by
chest X-ray
.
Some fluid may be removed with a nee-
dle and syringe and examined to find
the cause. A
biopsy
of the pleura may
also be needed. The underlying cause is
treated and fluid may be drained off to
relieve breathing problems.
pleurisy Inflammation of the
pleura
.
Causes include lung infections, such as
pneumonia
, or, more rarely,
pulmonary
embolism
,
lung cancer
, and
rheumatoid
arthritis
. Pleurisy causes a sharp chest
pain, which is worse when breathing in.
Treatment is of the underlying cause,
along with
analgesic drugs.
pleurodynia Pain in the chest caused
by coxsackievirus B infection. Sometimes
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