INTERVERTEBRAL FORAMEN
HOW INTERFERON FIGHTS VIRAL INFECTIONS
Interferon is part of the body’s immune system, providing a defence against many
different types of virally infected cells or tumour cells. It is produced naturally in
the body during viral infections, but can also be administered as a drug to enhance
its natural actions.
VIRAL MULTIPLICATION
1
A virus can multiply
only by first invading
one of its host’s cells.
2
The genetic material of
the virus takes over the
cell’s chemical machineryto
make copies ofthe virus.
Ö
-
m
3
The copies ofthe virus
escape, killing the host
cell, and invade more cells.
HOW INTERFERON WORKS
1
Interferon attaches to
the membrane of host
cells and primes them
against viral attack.
A n t iv ir a l
e n z y m e s
2
If a virus invades a cell
primed by interferon,
enzymes are produced
that impair viral copying.
3
Being unable to copy itself,
the virus is nullified, and
the infection is either stopped
altogether or shortened.
1
Interferon also causes
natural killer cells to
attack virally infected cells
or tumour cells.
2
A natural killer cell
attaches to the abnormal
host cell and makes the cell
disintegrate.
3
The effect ofthis process
is to help limit a viral
infection or to slow down
the growth of a tumour.
in te rs t itia l p u lm o n a ry f ib ro s is
S c a r r i n g o f l u n g t i s s u e m a i n l y a f f e c t i n g
t h e
a l v e o l i
( t h e
t i n y
a i r
s a c s
i n
t h e
l u n g s ; s e e
a l v e o l u s , p u l m o n a r y
).
I n t e r s t i -
t i a l p u l m o n a r y f i b r o s i s ( I P F ) m a y h a v e
v a r i o u s c a u s e s , i n c l u d i n g o c c u p a t i o n a l
e x p o s u r e
t o
m
i n e r a l
d u s t s ;
f i b r o s i n g
a l v e o l i t i s
( a n
a u t o i m m u n e
d i s o r d e r
i n
w
h i c h t h e i m
m
u n e s y s t e m a t t a c k s t h e
l u n g
t i s s u e ) ;
a n d a n
a l l e r g i c r e a c t i o n
( s e e
a l l e r g y
)
t h a t c a u s e s i n f l a m m
a t i o n
o f t h e a l v e o l i .
SYMPTOMS AND DIAGNOSIS
S y m p t o m s
o f
i n t e r s t i t i a l
p u l m o n a r y
f i b r o s i s i n c l u d e p r o g r e s s i v e s h o r t n e s s o f
b r e a t h , c o u g h i n g , c h e s t p a i n , a n d
c l u b -
b i n g
( a b n o r m a l t h i c k e n i n g a n d b r o a d -
e n i n g ) o f t h e f i n g e r t i p s . T h e r e m a y a l s o
b e a d d i t i o n a l s y m p t o m s c a u s e d b y a n y
u n d e r l y i n g d i s e a s e .
T h e d i a g n o s i s
o f I P F i s b a s e d o n t h e
s y m p t o m s a n d a p h y s i c a l e x a m i n a t i o n ;
i t
i s
c o n f i r m
e d
b y
c h e s t X - r a y
a n d
a
b i o p s y
( r e m o v a l
o f a
s a m p l e
o f l u n g
t i s s u e f o r m
i c r o s c o p i c e x a m i n a t i o n ) .
TREATMENT AND OUTLOOK
T r e a t m e n t
f o r
i n t e r s t i t i a l
p u l m o n a r y
f i b r o s i s
d e p e n d s
o n
t h e
c a u s e . T r e a t -
m
e n t
f o r
f i b r o s i n g
a l v e o l i t i s
o f t e n
i n c l u d e s
u s e
o f
i m m u n o s u p p r e s s a n t
d r u g s
a n d
c o r t i c o s t e r o i d d r u g s
,
w h i c h
s u p p r e s s
t h e
a c t i v i t y
o f t h e
i m
m
u n e
s y s t e m .
H o w e v e r ,
t h e r e
i s
n o
k n o w n
t r e a t m
e n t f o r l o c a l i z e d f i b r o s i s d u e t o
r a d i o t h e r a p y . I n o t h e r c a s e s , t r e a t m e n t
i s d i r e c t e d a t t h e u n d e r l y i n g c a u s e .
F o r p e o p l e w i t h f i b r o s i n g a l v e o l i t i s ,
t h e o u t l o o k i s p o o r : t h e l u n g s b e c o m
e
p r o g r e s s i v e l y
s t i f f e r
a n d
h e a r t f a i l u r e
a n d
b r o n c h o p n e u m o n i a
m a y
d e v e l o p .
T r a n s p l a n t a t i o n
o f a s i n g l e
l u n g
( s e e
t r a n s p l a n t s u r g e r y
)
m a y b e
c o n s i d e r e d .
T h e o u t l o o k o f o c c u p a t i o n a l d u s t d i s -
e a s e
d e p e n d s
o n
t h e
t y p e
o f
d u s t
i n v o l v e d a n d t h e l e v e l o f e x p o s u r e . I f
I P F i s d u e t o a n a l l e r g y , h o w e v e r , t h e
c o n d i t i o n
c a n
m
o r e
e a s i l y
b e
t r e a t e d
a n d t h e o u t l o o k i s b e t t e r .
in t e rs t it ia l ra d io th e ra p y
T r e a t m e n t
o f a
c a n c e r o u s
t u m o u r
b y
i n s e r t i n g r a d i o a c t i v e m a t e r i a l i n t o t h e
c a n c e r o u s g r o w t h
o r i n t o n e i g h b o u r -
i n g t i s s u e . U s i n g t h i s m
e t h o d , w
h i c h i s
a t y p e o f b r a c h y t h e r a p y , r a d i a t i o n c a n
b e t a r g e t e d a t t h e d i s e a s e d a r e a .
R a d i o a c t i v e
m a t e r i a l
( u s u a l l y a r t i f i -
c i a l r a d i o i s o t o p e s ) c o n t a i n e d i n w i r e s ,
s m a l l t u b e s , o r s e e d s i s i m p l a n t e d i n t o
o r
n e a r
t o
t h e
d i s e a s e d
t i s s u e
u n d e r
g e n e r a l
a n a e s t h e s i a
( s e e
a n a e s t h e s i a ,
g e n e r a l
) . T h e
m a t e r i a l i s
l e f t i n p l a c e
f o r v a r i a b l e a m o u n t s o f t i m
e d e p e n d -
i n g
o n
t h e
r a d i o a c t i v e
s u b s t a n c e
a n d
t h e
t u m o u r
t h a t
i s
b e i n g
t r e a t e d .
I n
s o m e c a s e s , s u c h a s i n p r o s t a t e c a n c e r ,
t h e
m a t e r i a l
i s
l e f t
i n
p l a c e
p e r m
-
a n e n t l y a s t h e r a d i a t i o n d e c a y s a f t e r a
r e l a t i v e l y
s h o r t
p e r i o d
o f t i m e .
( S e e
a l s o
r a d i o t h e r a p y
.)
in te rtrig o
I n f l a m
m
a t i o n
o f t h e s k i n d u e t o t w o
s u r f a c e s r u b b i n g t o g e t h e r . I n t e r t r i g o i s
m
o s t
c o m
m
o n
i n
o b e s e
p e o p l e . T h e
a f f e c t e d s k i n i s r e d a n d m
o i s t a n d m a y
h a v e a n u n p l e a s a n t o d o u r , a n d i s o f t e n
a c c o m p a n i e d
b y
a
f u n g a l
i n f e c t i o n
s u c h a s
c a n d i d i a s i s
;
t h e r e m a y a l s o b e
s c a l e s o r b l i s t e r s . T h e c o n d i t i o n w o r s -
e n s w i t h s w e a t i n g .
T r e a t m e n t c o n s i s t s o f w e i g h t r e d u c -
t i o n
a n d
k e e p i n g
t h e
a f f e c t e d
a r e a s
c l e a n
a n d
d r y .
A
c r e a m
c o n t a i n i n g
a n t i f u n g a l
d r u g s ,
w i t h
o r
w i t h o u t
a
c o r t i c o s t e r o i d ,
i s
u s e d
i f c a n d i d i a s i s
i s
f o u n d t o b e p r e s e n t .
in te rv e rte b ra l c a rtila g e
T h e
s t r o n g
t i s s u e ,
a l s o
c a l l e d
f i b r o -
c a r t i l a g e ,
t h a t
m a k e s
u p
t h e
p l a t e l i k e ,
s h o c k - a b s o r b i n g
d i s c s
b e t w e e n
t h e
b o n e s o f t h e s p i n e
( s e e
c a r t i l a g e
;
d i s c ,
i n t e r v e r t e b r a l
) .
in te rv e rte b ra l d is c
S e e
d i s c , i n t e r v e r t e b r a l
.
in te rv e rte b ra l fo ra m e n
A
n a t u r a l
o p e n i n g
b e t w e e n
a d j a c e n t
v e r t e b r a e
( t h e
s p i n a l
b o n e s )
i n
t h e
s p i n e
f o r m
e d
b y
t h e
s p a c e
b e t w e e n
I
431
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