(THEME)
VOICE ONE:
This is Steve Ember.
VOICE TWO:
And this is Sarah Long with Science in the News, a VOA Special
English program about recent developments in Science. Today,
we tell about the disease multiple sclerosis.
VOICE ONE:
Multiple sclerosis is not very easy to say. Those who suffer
from the disease may also have difficulty naming it. One of
the chief signs of multiple sclerosis is losing the ability
to speak clearly. It is estimated that more than one-million
people around the world suffer from multiple sclerosis, which
also is called M-S.
M-S is a disease of the brain and spinal cord. The cause of
the disease is not known. In patients with the disease, the
covering of the nerves is destroyed. This temporarily blocks
signals that pass through the nerves to the muscles of the body
and back to the brain. M-S especially affects the ability to
see, the sense of touch and the use of the arms and legs. Most
forms of the disease are described as progressive. This means
that the disease gets worse as time passes.
VOICE TWO:
Arrow points to early evidence of multiple sclerosis that can
be seen in the brain.
(Images - National Institutes of Health)
The central nervous system of the body includes the brain and
the spinal cord. The system contains millions of nerve cells
joined together by long thin fibers, like wires. Electric signals
start in nerve cells and travel along these fibers to and from
the brain. A fatty substance called myelin covers and protects
the fibers. Myelin works in the same way that protective coverings
work on electric wires.
In patients with M-S, the myelin becomes infected. It swells,
or grows larger, and loses its connection with the nerve fibers.
As time passes, the unconnected myelin is destroyed. Hardened
tissue called scar tissue then forms over the nerve fibers.
The process of hardening is called sclerosis. The word is from
Latin and means scar. The many areas of hardened or scar tissue
give the disease its name.
VOICE ONE:
In people with M-S, when nerve signals reach a damaged area,
some of the signals are blocked or delayed from traveling to
or from the brain. This results in problems in different places
throughout the body. These problems may appear and then disappear,
sometimes resulting in long periods when there are no problems
at all. Or, they may happen more and more often and become worse.
Doctors do not know what causes this process.
Health experts say the disease affects women two times as often
as men. And the experts say the average age of people found
to have the disease is between twenty and forty years old.
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VOICE TWO:
For many years, doctors believed that the cause of multiple
sclerosis was environmental. They believed this because a majority
of those suffering from the disease lived in northern Europe
and the northern half of the United States. In recent years,
however, they have changed their beliefs about the causes of
M-S.
Studies support the theory that there are several causes of
multiple sclerosis, instead of a single gene problem or one
environmental cause. The studies appear to show that genetic
problems are involved in making people likely to get the disease.
The studies also appear to show that environmental causes such
as viruses or bacteria also may be involved. However, researchers
have not identified just what those causes might be. Another
likely cause is a problem within the body¡¯s defense
system, when the defense system misunderstands signals and attacks
the body.
VOICE ONE:
Multiple sclerosis is different from many other diseases. The
signs or symptoms of the disease are not always the same. Sometimes
symptoms of M-S appear and then disappear for a long time. For
example, one of the symptoms is a lack of feeling in one part
of the body or another.
Two other symptoms of the disease are muscle weakness or tiredness.
However, these signs also could be caused by other health problems
that are not M-S. Other signs include a loss of the ability
to move normally, or a loss of balance. A person suffering from
M-S also may have difficulty seeing well or speaking clearly.
VOICE TWO:
Doctors who suspect a patient has M-S must carry out a number
of tests and study the patient¡¯s history of health
problems. Signs of M-S can depend on where the nerve scars are
in the body¡¯s central nervous system. And some of
these signs are not always easy to see.
Magnetic Resonance Imaging is one way to tell if a patient
has multiple sclerosis. The test, also known as M-R-I, involves
studying the magnetic signals from all the cells in the body.
An M-R-I can show if there are scars from M-S along a patient¡¯s
nerves. A doctor can use this test to tell if a patient might
have the disease, as well as by studying the patient¡¯s
medical history.
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VOICE ONE:
There are five main kinds of multiple sclerosis. The first
kind is called Benign. This is the form of M-S that is not progressive.
In ten to fifteen percent of M-S patients, the symptoms are
moderate and not severe. The problems do not grow worse. They
do not lead to a person becoming permanently disabled.
The second kind of M-S is called Relapsing-Remitting. About
eighty-five percent of M-S patients begin with this form of
the disease. More than half of M-S patients have this form at
any one time. These patients have one or two major M-S-related
problems every one to three years. Then they have periods with
no signs of the disease. The symptoms appear suddenly and last
a few weeks or months before slowly disappearing. However, the
signs of the disease may become worse each time they appear.
VOICE TWO:
The third kind of M-S is called Primary Progressive. In this
form of M-S, the signs of the disease appear and begin to grow
worse, with no periods of disappearance. About ten to fifteen
percent of patients begin their struggle with M-S this way.
The fourth kind of M-S is called Secondary Progressive. This
form of the disease affects
about fifty percent of those with the Relapse-Remitting form
of M-S. It begins to affect them several years after they have
had Relapse-Remitting M-S. When the disease changes to Secondary
Progressive, the disease begins to grow worse and worse.
The fifth kind of M-S is called Progressive Relapsing. It is
the worst form of multiple sclerosis. New signs of M-S can appear
while existing ones grow worse. This form of the disease is
rare. It affects only five percent of M-S cases.
VOICE ONE:
Scientists say multiple sclerosis does not appear to be passed
from parents to children. However, it does appear to be found
in families. As many as twenty percent of people with M-S have
at least one affected family member. And, people whose close
family members have the disease have as much as a forty percent
chance of also developing M-S.
It does not appear that one gene is responsible for M-S. Instead,
several genes may increase the possibility that a person will
develop M-S.
Common viruses or bacteria may also increase the chances that
some people will develop the disease.
As with many diseases, early discovery and treatment can make
a major difference in a person¡¯s life.
VOICE TWO:
M-S does not always result in severe disability. Many people
are able to live normal lives. There is no cure for multiple
sclerosis. However, there are new treatments for M-S that ease
the symptoms of the disease. Some new treatments also can slow
the progression of the disease.Several kinds of drugs are used
to treat M-S. Some drugs reduce the swelling in nerve tissue.
Drugs known as beta interferons also are used to treat M-S.
Interferons are genetically engineered copies of proteins found
naturally in the body. These proteins help fight viral infections
and help the body¡¯s defense system against disease.
Some M-S patients inject these beta interferon drugs. However,
this treatment is very costly. And some patients develop side
effects.
Scientists around the world are working to develop new treatments
for M-S. Researchers in the United States are carrying out more
than twelve studies of possible treatments. Doctors are hopeful
that new treatments will help patients with multiple sclerosis
in the future.
(THEME)
VOICE ONE:
This SCIENCE IN THE NEWS program was written by Oliver Chanler.
This is Steve Ember.
VOICE TWO:
And this is Sarah Long. Join us again next week for more news
about science in Special English on the Voice of America.
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This Science Report is published courtesy
of VOAnews.com
