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Parkinson's
Disease
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Causes
Although Parkinson's disease was discovered over a century
ago the exact cause of the disease remains a mystery.
Bodily movements are regulated by a portion of the brain
called the basal ganglia, whose cells require a proper balance of two substances called
dopamine and acetylcholine, both involved in the transmission of nerve impulses. In
Parkinson's, cells that produce dopamine begin to degenerate. Insufficient dopamine
disturbs the balance between dopamine and other transmitters, such as acetylcholine.
Dopamine is a chemical messenger responsible for transmitting signals between the
substantia nigra and the next "relay station" of the brain, the corpus striatum,
to produce smooth, purposeful muscle activity. Loss of dopamine causes the nerve cells of
the striatum to fire out of control, leaving patients unable to direct or control their
movements in a normal manner. Studies have shown that Parkinson's patients have a loss of
80 percent or more of dopamine-producing cells in the substantia nigra.
The exact cause of this cell death or impairment is not
known. Significant findings have been made by research scientists lately that provide
important new clues to the disease. One theory holds that free radicals-unstable and
potentially damaging molecules generated by normal chemical reactions in the body--may
contribute to nerve cell death, thereby leading to Parkinson's disease.
Free Radicals and Anti-Oxidants
Free radicals are the highly unstable
chemicals that attack, infiltrate, and injure vital cell structures. Most stable chemical
compounds in the body possess a pair of electrons. Sometimes, one member of the electron
pair gets stripped away. The resulting compound (less one electron) is called a free
radical.
In chemistry, the term free radical means
that it is now free to combine with another element to form a new stable compound. One way
to think of free radical is the way our social system work. In a family there is husband
and wife. They are joined together. Both are "tied up" or not available for
other partners. Now, for some reason they get separated. Now both mates can look for
another person to join together. The way free radicals work, one of these free spouse go
and break up a stable marriage of another couple, by joining with one of the spouses. This
results in the ouster of a person from that family creating a brand new "free
radical" who goes around prowling to find another "compound" to attack. You
can see that free radicals can do lot of harm by forming a chain reaction.
A similar thing happens with free radicals
in the body. When a free radical is born, it goes around the body looking for another
compound to steal an electron from. This breaks up this"contented" couple, that
results in releasing another free radical, and so on. While on the prowl, these free
radicals (which are really the oxidation products from the body) can do tremendous damage
to the delicate machinery of your cells. The most studied free radical chain reaction in
living things is lipid peroxidation. (The term lipid refers to any fat-soluble substance,
animal or vegetable. Peroxidation means the formation of a peroxide molecule. These are
the molecules with the greatest proportion of oxygen molecules. For example, water
molecule has tow hydrogen atoms and one oxygen atom. Hydrogen peroxide has two Hydrogen
atoms and two oxygen atoms. In other words, there is an excess oxygen atom in hydrogen
peroxide.)
Ninety eight percent of the oxygen we
breathe is used by tiny powerhouses within our cells called mitochondria, that convert
sugar, fats and inorganic phosphate (ADP), oxygen into adenosine triphosphate (ATP), the
universal form of energy we need to live. This energy producing activity of the
mitochondria involves a series of intricate, complex and vital biochemical processes
dependent on vast numbers of enzymes (estimates vary from 500 to 10,000 sets of oxidative
enzymes). These, in turn, are dependent upon dozens of nutrient factors and co-factors. In
this metabolism process a very small amount of left over oxygen loses electrons, creating
free radicals. These free radicals burn holes in our cellular membranes. Calcium penetrate
our cells through these holes. This excess calcium results in cell death. This, in turn,
weakens tissues and organs. As this damage continues, our body become "rusty",
less able to fight other invaders such as cancer, hardening of the arteries, premature
aging, and other bodily disorders.
Because of the amount of oxygen we breathe
every day (our bodies take 630 quadrillion damaging oxygen hits per day. This means each
of our cells takes about 10,000 hits per day and each DNA strand in the cell gets hit
5,000 times per day. This free radical bombardment causes a typical human cell to undergo
thousands of changes or mutations daily.If a DNA strand gets hit and it is not repaired
before its twin gets hit, we will have the onset to a potentially lethal cancer.
In addition to the oxygen we breathe, the
free radicals can also come from such things as environmental pollution, radiation,
cigarette smoke, chemicals, and herbicides.
The key to having a healthy body is to
repair the damages caused by the free radicals before it is too late, and to protect the
body's tissue cells from the free radicals before they cause mutations. Antioxidants are
substances that have free-radical chain-reaction-breaking properties. Like a bouncer, the
antioxidants deactivate potentially dangerous free radicals before they can damage a cells
machinery. Most of these antioxidants come from plants and are called phytochemicals. More
than 60,000 such plant chemicals are identified. Among the most effective and dedicated
antioxidants are Vitamin A, C, and E (known as the ACE trio against cancer.). Out of
these, Vitamin C is the most powerful.
Each cell produces its own antioxidants.
But the ability to produce them decreases as we age. That is why diet rich in anti-oxidant
and phytochemical rich fruits and vegetables supplemented with additional vitamins and
minerals is important. |
Oxidation due
to free radicals is thought to cause damage to tissues, including neurons. Normally, free
radical damage is kept under control by antioxidant chemicals that protect cells from this
damage. Researchers found that patients with Parkinson's disease have increased brain
levels of iron, especially in the substantia nigra, and decreased levels of feritin, which
serves as a protective mechanism by chelating, or forming a ring around the iron, and
isolating it. This led to the conclusion that oxidative mechanisms may cause or contribute
to Parkinson's disease.
Parkinson's disease may occur when either an external or an internal toxin selectively destroys
dopaminergic neurons. An environmental risk factor such as exposure to pesticides or a
toxin in the food supply is an example of the kind of external trigger that could
hypothetically cause Parkinson's disease. The theory is based on the fact that there are a
number of toxins, such as 1-methyl 4-phenyl-1,2,3,6,-tetra- hydropyridine (mptp) and
neuroleptic drugs, that induce parkinsonian symptoms in humans. So far no research has
provided conclusive proof that a toxin is the cause of the disease.
Researchers believe that genetics
sometimes plays a role in the cellular breakdown. Fifteen to twenty percent of Parkinson's
patients have a close relative who has experienced parkinsonian symptoms (such as a
tremor). After studies in animals showed that mptp interferes with the function of
mitochondria within nerve cells, investigators became interested in the possibility that
impairment in mitochondrial DNA may be the cause of Parkinson's disease. Mitochondria is
found in all animal cells that convert the energy in food into fuel for the cells.
In some individuals, the normal, age-related
wearing away of dopamine-producing neurons accelerates. The exact cause for this is not
known; but, if this happens, then it can also result in Parkinson's disease. This theory
is supported by the fact that the loss of antioxidative protective mechanisms is
associated with both Parkinson's disease and increasing age.
In rare instances, Parkinson's disease may be caused by a viral infection.
Many researchers believe that a combination of
oxidative damage, environmental toxins, genetic predisposition, and accelerated aging may
ultimately be shown to cause the disease.
The typical symptoms of Parkinson's also occur in
meningitis and various types of poisoning from alcohol, carbon monoxide and heavy metals.
This group of symptoms is called Parkinsonism. Overdoses of manganese also cause
Parkinson's symptoms, and high levels of stored iron are found in those with Parkinson's
disease. Other causes of parkinsonism include:
 | An adverse reaction to prescription drugs |
 | Use of illegal drugs |
 | Exposure to environmental toxins |
 | Stroke |
 | Thyroid and parathyroid disorders |
 | Repeated head trauma (for example, the trauma associated
with boxing) |
 | Brain tumor |
 | An excess of fluid around the brain (called hydrocephalus) |
 | Brain inflammation (encephalitis) resulting from infection |
Parkinsonism may also be present in persons with other
neurological conditions, including Alzheimer's disease, amyotrophic lateral sclerosis
(ALS), Creutzfeldt-Jakob disease, Wilson's disease and Huntington's disease.
Poor nutrition is an underlying cause of Parkinson's
disease. High consumption of meat, rich in protein, also aggravates symptoms of
Parkinson's and inhibits the body's use of vitamin B-6, which helps treat brain
dysfunction.
Symptoms of Parkinson's should not be confused with milder
problems that are common as people get older, including slower, stiffer movements from
aching joints, and trembling. Problems with poor memory and a lack of facial expression
are often linked to depression.
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