FREE ESSAY ON DISESES

DISESES

Multiple Sclerosis 
Multiple Sclerosis (MS) is a chronic, often disabling disease that randomly attacks the
central nervous system (brain and spinal cord). The progress, severity and specific
symptoms of the disease can not be predicted; symptoms may range from tingling and
numbness to paralysis and blindness. MS is a devastating disease because people live with
its unpredictable physical and emotional effects for the rest of their lives. MS is a
well-known disease, but poorly understood. In the United States there are approximately
200 new cases diagnosed each week; MS is a common disease and not always caused by
genetics. Therefore, I feel we all need to have a better understanding of this disease
that has no cure yet. I hope to make MS more understanding in my paper. In my paper I
will explain what MS is, who gets MS, what MS has to do with the metabolism, some new
techniques being used to pinpoint genetic factors, what some of the symptoms of MS is,
and some treatments for MS. Multiple Sclerosis Multiple sclerosis (MS) is a progressive
disabling illness that affects nerve cells in the brain and spinal cord (Bernard). Under
normal conditions these nerve cells are surrounded by an insulating sheath made of fatty
myelin, which speeds the passage of nerve impulses. In MS, this myelin sheath is inflamed
or damaged, disrupting nerve impulses and leaving areas of scarring (sclerosis). The
disruption of nerve signals within the brain and spinal cord causes a variety of symptoms
that may affect vision, sensation, and body movements. "These symptoms usually wax and
wane through a series of relapses (episodes when symptoms suddenly get worse) alternating
with remissions (periods of recovery, when symptoms improve)." (Brunnscheiler) For many
patients, a long history of MS attacks over several decades leads to slowly progressing
disability, but for others the disability is more rapid and severe. MS is a life-long
chronic disease diagnosed primarily in young adults who have a virtually normal life
expectancy. Consequently, the economic, social, and medical costs associated with the
disease are significant. Estimates place the annual costs of MS in the United States in
excess of $2.5 billion. (Melvin) No one knows exactly how many people have MS. It is
believed that, currently, there are approximately 250,000 to 350,000 people in the United
States with MS diagnosed by a physician. (Boyden) This estimate suggests that
approximately 200 new cases are diagnosed each week. Also, MS is the most common nerve
disease to develop in young persons after birth, and it affects over 1 million young
adults worldwide. "Close relatives of a person with MS are 8 times more likely than
average to develop the disease themselves, and children of a person with MS run 30 to 50
times the average risk." (Waxman) Most people experience their first symptoms of MS
between the ages of 20 and 40, but a diagnosis is often delayed. This is due to both the
transitory nature of the disease and the lack of a specific diagnostic test--specific
symptoms and changes in the brain must develop before the diagnosis is confirmed. (Health
Central) Although scientists have documented cases of MS in young children and elderly
adults, symptoms rarely begin before age 15 or after age 60. Whites are more than twice
as likely as other races to develop MS. In general, women are affected at almost twice
the rate of men; however, among patients who develop the symptoms of MS at a later age,
the gender ratio is more balanced. (Waxman) To understand what is happening when a person
has MS, it is first necessary to know a little about how the healthy immune system works.
The immune system -- a complex network of specialized cells and organs -- defends the
body against attacks by foreign invaders such as bacteria, viruses, fungi, and parasites.
It does this by seeking out and destroying the interlopers as they enter the body.
Substances capable of triggering an immune response are called antigens. (Hofmann) "The
immune system displays both enormous diversity and extraordinary specificity." (Hofmann)
It can recognize millions of distinctive foreign molecules and produce its own molecules
and cells to match up with and counteract each of them. In order to have room for enough
cells to match the millions of possible foreign invaders, the immune system stores just a
few cells for each specific antigen. When an antigen appears, those few specifically
matched cells are stimulated to multiply into a full-scale army. Later, to prevent this
army from overexpanding, powerful mechanisms to suppress the immune response come into
play. T-cells, so named because they are processed in the thymus, appear to play a
particularly important role in MS. They travel widely and continuously throughout the
body patrolling for foreign invaders. In order to recognize and respond to each specific
antigen, each T cell's surface carries special receptor molecules for particular
antigens. T cells contribute to the body's defenses in two major ways. "Regulatory T
cells help orchestrate the elaborate immune system. " ( Kaser) For instance, they assist
other cells to make antibodies, proteins programmed to match one specific antigen much as
a key matches a lock. Antibodies typically interact with circulating antigens, such as
bacteria, but are unable to penetrate living cells. Chief among the regulatory T cells
are those known as helper (or inducer) cells. "Helper T cells are essential for
activating the body's defenses against foreign substances. " (Kaser) Yet another subset
of regulatory T cells acts to turn off, or suppress, various immune system cells when
their job is done. Killer T cells, on the other hand, directly attack diseased or damaged
body cells by binding to them and bombarding them with lethal chemicals called cytokines.
( Kaser) Since T cells can attack cells directly, they must be able to discriminate
between self cells (those of the body) and nonself cells (foreign invaders). To enable
the immune system to distinguish the self, each body cell carries identifying molecules
on its surface. T cells likely to react against the self are usually eliminated before
leaving the thymus; the remaining T cells recognize the molecular markers and coexist
peaceably with body tissues in a state of self-tolerance. "In autoimmune diseases such as
MS, the detente between the immune system and the body is disrupted when the immune
system seems to wrongly identify self as nonself and declares war on the part of the body
(myelin) it no longer recognizes." (Hauser) Through intensive research efforts,
scientists are unraveling the complex secrets of the malfunctioning immune system of
patients with MS. Components of myelin such as myelin basic protein have been the focus
of much research because, when injected into laboratory animals, they can precipitate
experimental allergic encephalomyelitis (EAE), a chronic relapsing brain and spinal cord
disease that resembles MS. The injected myelin probably stimulates the immune system to
produce anti-myelin T cells that attack the animal's own myelin. (Leuven) Investigators
are also looking for abnormalities or malfunctions in the blood/brain barrier, a
protective membrane that controls the passage of substances from the blood into the
central nervous system. It is possible that, in MS, components of the immune system get
through the barrier and cause nervous system damage. "Scientists have studied a number of
infectious agents (such as viruses) that have been suspected of causing MS, but have been
unable to implicate any one particular agent." (Mayo Clinic) Viral infections are usually
accompanied by inflammation and the production of gamma interferon, a naturally occurring
body chemical that has been shown to worsen the clinical course of MS. It is possible
that the immune response to viral infections may themselves precipitate an MS attack.
"The genes a person inherits may help determine whether that person is at increased risk
for developing MS." ( Melvin) While there is evidence from studies that this genetic
component exists, it appears to be only one factor among several. Most likely an
individual's genetic blueprint ultimately determines if that individual will be
susceptible to a triggering factor, which in turn initiates the autoimmune process that
leads to the development of MS. In the past few years, scientists have developed a set of
tools that gives them the ability to pinpoint the genetic factors that make a person
susceptible to MS. "These tools are the methods of molecular genetics-techniques used to
isolate and determine the chemical structure of genes." (Colin) In the 1980s, scientists
began to apply the tools of molecular genetics to human diseases caused by defects in
single genes. This work led to major advances in understanding diseases such as Duchenne
muscular dystrophy and cystic fibrosis. The situation for diseases such as multiple
sclerosis is more complicated. Scientists now believe that a person is susceptible to
multiple sclerosis only if he or she inherits an unlucky combination of several genes.
(Colin) Advances in molecular genetics and the identification of large families in which
several members have MS-multiplex MS families-have made possible research to uncover MS
susceptibility genes. "Since 1991, the National MS Society has supported an international
project searching for these genes." ( National Multiple Sclerosis Society) However, even
though genetic (inherited) factors seem to play a large role in the development of MS, no
single MS gene has been identified so far. Instead, scientists suspect that MS develops
because of the influence of several genes acting together. Many multiplex families from
throughout the world have agreed to participate in these studies. The researchers are
looking for patterns of genetic material that are consistently inherited by people with
MS. These recognizable patterns are called DNA markers. (Melvin) When one of these
markers is identified, scientists focus on that area, seeking additional markers closer
to that gene. Eventually the location of that gene can be identified. This process of
moving closer to the gene until it is identified has to be repeated for each of the
marker regions from the multiplex families. (Melvin) By 1996, as many as 20 locations
that may contain genes contributing to MS were identified, but no single gene was shown
to have a major influence on susceptibility to MS. (Melvin) Research will likely find
that other, as yet unidentified, genes contribute to MS. After the location of each
susceptibility gene is identified, the role that the gene plays in the immune system and
neuralgic aspects of people with MS will have to be determined. Because the immune system
is so involved in MS, many scientists think at least some of the susceptibility genes are
related to the immune system. Already there have been reports linking some immune system
genes to MS. Further indications that more than one gene is involved in MS susceptibility
comes from studies of families in which more than one member has MS. Several research
teams found that people with MS inherit certain regions on individual genes more
frequently than people without MS. Of particular interest is the human leukocyte antigen
(HLA) or major histocompatibility complex region on chromosome 6. HLAs are genetically
determined proteins that influence the immune system. ( Kaser) The HLA patterns of MS
patients tend to be different from those of people without the disease. Investigations in
northern Europe and America have detected three HLAs that are more prevalent in people
with MS than in the general population. Studies of American MS patients have shown that
people with MS also tend to exhibit these HLAs in combination--that is, they have more
than one of the three HLAs--more frequently than the rest of the population. Furthermore,
there is evidence that different combinations of the HLAs may correspond to variations in
disease severity and progression. ( Kaser) Studies of families with multiple cases of MS
and research comparing genetic regions of humans to those of mice with EAE suggest that
another area related to MS susceptibility may be located on chromosome 5. Other regions
on chromosomes 2, 3, 7, 11, 17, 19, and X have also been identified as possibly
containing genes involved in the development of MS. (Hauser) These studies strengthen the
theory that MS is the result of a number of factors rather than a single gene or other
agent. Development of MS is likely to be influenced by the interactions of a number of
genes, each of which (individually) has only a modest effect. Additional studies are
needed to specifically pinpoint which genes are involved, determine their function, and
learn how each gene's interactions with other genes and with the environment make an
individual susceptible to MS. "In addition to leading to better ways to diagnose MS, such
studies should yield clues to the underlying causes of MS and, eventually, to better
treatments or a way to prevent the disease." (Ronthal) Finding the genes responsible for
susceptibility to MS may lead to the development of new and more effective ways to treat
the disease. Such research could also uncover the basic cause of the disease and help
predict the course of the disease in an individual. This would make it easier for
physicians to tailor therapies and provide information to help people make life
decisions. Another possible benefit may be the early diagnosis of people in families
where one or more member already has MS. Many physicians believe that the earlier MS is
diagnosed and treatment begun, the better the outcome will be. Symptoms of MS may be mild
or severe, of long duration or short, and may appear in various combinations, depending
on the area of the nervous system affected. Complete or partial remission of symptoms,
especially in the early stages of the disease, occurs in approximately 70 percent of MS
patients. "The initial symptom of MS is often blurred or double vision, red-green color
distortion, or even blindness in one eye." (Brunnscheiler) Inexplicably, visual problems
tend to clear up in the later stages of MS. Inflammatory problems of the optic nerve may
be diagnosed as retrobulbar or optic neuritis. Fifty-five percent of MS patients will
have an attack of optic neuritis at some time or other and it will be the first symptom
of MS in approximately 15 percent. This has led to general recognition of optic neuritis
as an early sign of MS, especially if tests also reveal abnormalities in the patient's
spinal fluid. (National Multiple Sclerosis Society) Most MS patients experience muscle
weakness in their extremities and difficulty with coordination and balance at some time
during the course of the disease. These symptoms may be severe enough to impair walking
or even standing. In the worst cases, MS can produce partial or complete paralysis.
"Spasticity, the involuntary increased tone of muscles leading to stiffness and
spasms--is common, as is fatigue." (Brunnscheiler) Fatigue may be triggered by physical
exertion and improve with rest, or it may take the form of a constant and persistent
tiredness. Most people with MS also exhibit paresthesias, transitory abnormal sensory
feelings such as numbness, prickling, or pins and needles sensations; uncommonly, some
may also experience pain. Loss of sensation sometimes occurs. Speech impediments,
tremors, and dizziness are other frequent complaints. Occasionally, people with MS have
hearing loss. (Brunnscheiler ; National Multiple Sclerosis Society) Approximately half of
all people with MS experience cognitive impairments such as difficulties with
concentration, attention, memory, and poor judgment, but such symptoms are usually mild
and are frequently overlooked. In fact, they are often detectable only through
comprehensive testing. Patients themselves may be unaware of their cognitive loss; it is
often a family member or friend who first notices a deficit. Such impairments are usually
mild, rarely disabling, and intellectual and language abilities are generally spared.
(Brunnscheiler) "Cognitive symptoms occur when lesions develop in brain areas responsible
for information processing." (Brunnscheiler) These deficits tend to become more apparent
as the information to be processed becomes more complex. Fatigue may also add to
processing difficulties. Scientists do not yet know whether altered cognition in MS
reflects problems with information acquisition, retrieval, or a combination of both.
Types of memory problems may differ depending on the individual's disease course
(relapsing-remitting, primary-progressive, etc.), but there does not appear to be any
direct correlation between duration of illness and severity of cognitive dysfunction.
(National Multiple Sclerosis Society) "Depression, which is unrelated to cognitive
problems, is another common feature of MS. (Brunnscheiler) In addition, about 10 percent
of patients suffer from more severe psychotic disorders such as manic-depression and
paranoia. Five percent may experience episodes of inappropriate euphoria and
despair--unrelated to the patient's actual emotional state known as laughing/weeping
syndrome. This syndrome is thought to be due to demyelination in the brainstem, the area
of the brain that controls facial expression and emotions, and is usually seen only in
severe cases. (National Multiple Sclerosis Society) As the disease progresses, sexual
dysfunction may become a problem. Bowel and bladder control may also be lost. (Health
Central) In about 60 percent of MS patients, heat, whether generated by temperatures
outside the body or by exercise may cause temporary worsening of many MS symptoms. In
these cases, eradicating the heat eliminates the problem. Some temperature-sensitive
patients find that a cold bath may temporarily relieve their symptoms. For the same
reason, "swimming is often a good exercise choice for people with MS." (Wenzel) The
erratic symptoms of MS can affect the entire family as patients may become unable to work
at the same time they are facing high medical bills and additional expenses for
housekeeping assistance and modifications to homes and vehicles. The emotional drain on
both patient and family is immeasurable. Counseling may help MS patients, their families,
and friends find ways to cope with the many problems the disease can cause. (Lambert)
"There is as yet no cure for MS. Many patients do well with no therapy at all, especially
since many medications have serious side effects and some carry significant risks."
(Health Central) Naturally occurring or spontaneous remissions make it difficult to
determine therapeutic effects of experimental treatments; however, the emerging evidence
that MRIs can chart the development of lesions is already helping scientists evaluate new
therapies. Until recently, the principal medications physicians used to treat MS were
steroids possessing anti-inflammatory properties; these include adrenocorticotropic
hormone (better known as ACTH), prednisone, prednisolone, methylprednisolone,
betamethasone, and dexamethasone. Studies suggest that intravenous methylprednisolone may
be superior to the more traditional intravenous ACTH for patients experiencing acute
relapses; no strong evidence exists to support the use of these drugs to treat
progressive forms of MS. Also, there is some indication that steroids may be more
appropriate for people with movement, rather than sensory, symptoms. (Mayo Clinic) While
steroids do not affect the course of MS over time, they can reduce the duration and
severity of attacks in some patients. The mechanism behind this effect is not known; one
study suggests the medications work by restoring the effectiveness of the blood/brain
barrier. "Because steroids can produce numerous adverse side effects (acne, weight gain,
seizures, psychosis), they are not recommended for long-term use." (Bernard) One of the
most promising MS research areas involves naturally occurring antiviral proteins known as
interferons. Two forms of beta interferon (Avonex and Betaseron) have now been approved
by the Food and Drug Administration for treatment of relapsing-remitting MS. A third form
(Rebif) is marketed in Europe. Beta interferon has been shown to reduce the number of
exacerbation's and may slow the progression of physical disability. When attacks do
occur, they tend to be shorter and less severe. In addition, MRI scans suggest that beta
interferon can decrease myelin destruction. (Mayo Clinic) Investigators speculate that
the effects of beta interferon may be due to the drug's ability to correct an MS-related
deficiency of certain white blood cells that suppress the immune system and/or its
ability to inhibit gamma interferon, a substance believed to be involved in MS attacks.
Alpha interferon is also being studied as a possible treatment for MS. (Mayo Clinic)
"Common side effects of interferons include fever, chills, sweating, muscle aches,
fatigue, depression, and injection site reactions." (Health Central) Scientists continue
their extensive efforts to create new and better therapies for MS. Goals of therapy are
threefold: to improve recovery from attacks, to prevent or lessen the number of relapses,
and to halt disease progression. In conclusion, MS is a disease that is well known but
poorly understood by the medical and nursing community as well as the general public. It
has no known cure and the genes that are accountable for it have yet been pin pointed.
The United States is capable of finding a cure for this disease; over the years, medical
researchers have found cures for many diseases that were thought incurable. Not only time
and money are needed to find a cure for this disease, but faith and heart are needed to
realize the importance Glossary antibodies -- proteins made by the immune system that
bind to structures (antigens) they recognize as foreign to the body. antigen -- a
structure foreign to the body, such as a virus. The body usually responds to antigens by
producing antibodies. ataxia -- a condition in which the muscles fail to function in a
coordinated manner. autoimmune disease -- a disease in which the body's defense system
malfunctions and attacks a part of the body itself rather than foreign matter.
blood/brain barrier -- a membrane that controls the passage of substances from the blood
into the central nervous system. cerebrospinal fluid -- the colorless liquid, consisting
partially of substances filtered from blood and partially by secretions released by brain
cells, that circulates around and through the cavities of the brain and spinal cord.
Physicians use a variety of tests--electrophoresis, isoelectric focusing, capillary
isotachophoresis, and radioimmunoassay--to study cerebrospinal fluid for abnormalities
often associated with MS. cytokines -- powerful chemical substances secreted by T cells.
Cytokines are an important factor in the production of inflammation and show promise as
treatments for MS. demyelination -- damage caused to myelin by recurrent attacks of
inflammation. Demyelination ultimately results in nervous system scars, called plaques,
which interrupt communications between the nerves and the rest of the body. experimental
allergic encephalomyelitis (EAE) -- a chronic brain and spinal cord disease similar to MS
which is induced by injecting myelin basic protein into laboratory animals. fatigue --
tiredness that may accompany activity or may persist even without exertion. gadolinium --
a chemical compound given during MRI scans that helps distinguish new lesions from old.
human leukocyte antigens (HLAs) -- antigens, tolerated by the body, that correspond to
genes that govern immune responses. Also known as major histocompatibility complex.
immunoglobulin G (IgG) -- an antibody-containing substance produced by human plasma cells
in diseased central nervous system plaques. Levels of IgG are increased in the
cerebrospinal fluid of most MS patients. immunosuppression -- suppression of immune
system functions. Many medications under investigation for the treatment of MS are
immunosuppressants. interferons -- cytokines belonging to a family of antiviral proteins
that occur naturally in the body. Gamma interferon is produced by immune system cells,
enhances T-cell recognition of antigens, and causes worsening of MS symptoms. Alpha and
beta interferon probably exert a suppressive effect on the immune system and may be
beneficial in the treatment of MS. lesion -- an abnormal change in the structure of an
organ due to disease or injury. magnetic resonance imaging (MRI) -- a non-invasive
scanning technique that enables investigators to see and track MS lesions as they evolve.
myelin -- a fatty covering insulating nerve cell fibers in the brain and spinal cord,
myelin facilitates the smooth, high-speed transmission of electrochemical messages
between these components of the central nervous system and the rest of the body. In MS,
myelin is damaged through a process known as demyelination, which results in distorted or
blocked signals. myelin basic protein (MBP) -- a major component of myelin. When myelin
breakdown occurs (as in MS), MBP can often be found in abnormally high levels in the
patient's cerebrospinal fluid. When injected into laboratory animals, MBP induces
experimental allergic encephalomyelitis, a chronic brain and spinal cord disease similar
to MS. oligodendrocytes -- cells that make and maintain myelin. optic neuritis -- an
inflammatory disorder of the optic nerve that usually occurs in only one eye and causes
visual loss and sometimes blindness. It is generally temporary. paresthesias -- abnormal
sensations such as numbness, prickling, or pins and needles. plaques -- patchy areas of
inflammation and demyelination typical of MS, plaques disrupt or block nerve signals that
would normally pass through the regions affected by the plaques. receptor -- a protein on
a cell's surface that allows the cell to identify antigens. retrobulbar neuritis -- an
inflammatory disorder of the optic nerve that is usually temporary. It causes rapid loss
of vision and may cause pain upon moving the eye. spasticity -- involuntary muscle
contractions leading to spasms and stiffness or rigidity. In MS, this condition primarily
affects the lower limbs. T cells -- immune system cells that develop in the thymus gland.
Findings suggest that T cells are implicated in myelin destruction. transverse myelitis
-- an acute spinal cord disorder causing sudden low back pain and muscle weakness and
abnormal sensory sensations in the lower extremities. Transverse myelitis often remits
spontaneously; however, severe or long-lasting cases may lead to permanent disability.
white matter -- nerve fibers that are the site of MS lesions and underlie the gray matter
of the brain and spinal cord. 
Bibliography 
Bibliography Bernard, Bobby. "Multiple Sclerosis Continues to Puzzle Scientists." The
Vermillion March 1998. Brunnscheiler, H. "Problems Associated with MS" (July 28, 1999)
"Inteli Health" http://www.intelihealth.com/ (28 July 1999). Boyden, Kathleen M.
"Compolmer-1 in the Treatment of Multiple Sclerosis." Journal of Neuroscience Nursing 5
October 1998. Waxman, Stephen. "Demyelinating Diseases -- New Pathological Insights, New
Therapeutic Targets." New England Journal of Medicine 29 Jan. 1998, Vol. 338, No. 5,
323-327. Health Central "General Information about Multiple Sclerosis" (July 16, 1999)
Hofmann, Robert. " Multiple Sclerosis" American Journal of Human Genetics June 1998,
62:492-495 Kaser, Arthur. "Inter