File

advertisement
The Psychology of a Prion
Sarah Themel
This is your brain…
This is Your Brain on Prions
What is a Prion?
•
•
•
•
•
•
Prion diseases are called spongiform encephalopathies. They
impair brain functions, leading to both mental and physical
deterioration over short periods of time.
Though few have heard the term “prion,” almost
everyone has heard of the diseases they cause.
They have been found in MANY species
Their structure is extremely stable, making
them nearly indestructible. That is why there
is no known cure or treatment for any
disease caused by prions; they are ALWAYS
fatal. Most victims remain cognitive and well
aware of their situation up until death.
Diseases caused by prions can be: sporadic,
infectious, and genetic. No other disease
has the ability to infect in all three ways.
Different strains of prions cause specific and very distinct diseases.
PrP and Me
•
•
•
The protein PrP is found throughout our bodies; it’s exact purpose is unknown
A prion is this same exact protein misfolded, or mutated, changing it’s structure. This new structure is called
PrPSC , aka a prion.
The prions link up, joining together to form prion rods. The rods accumulate in the brain, causing:
Tissue damage, cell death, loss of neurons, neuronal swelling, proliferation of astrocytes (these are star shaped
cells that are usually a sign of the brains attempt to repair damage),and gliosis (the proliferation of infection
fighting cells in the brain)
Prions are also responsible for the formation of amyloid plaques that lead to neurodegeneration (also found in
other neurodegenerative diseases like Alzheimer's)
•
•
•
•
•
CJD and Me
Weakness and pain in legs, which leads to stiffness and changes in gait. Eventually
patients lose their ability to walk.
clumsiness or incordination; Muscle twitching and shaking
Disturbances of general motor skills and sensation
Dementia and other psychiatric and behavioral problems. These striking mental
changes include: mood swings, depression, anxiety, memory lapses, social
withdrawal, disorientation, hallucinations, and extreme dementia
Rare cases can also lead to seizures and blindness
•
•
•
•
•
•
•
CJD
Creutzfeldt–Jakob Disease (CJD) is the most common type of transmissible spongiform
encephalopathy found in humans
Severe thalamic and basal ganglia gliosis along with spongiform changes are the most
prominent histological features.
It can be either genetic (with a 50% chance of passing it to offspring) or sporadic (appearing
for no known reason). There are also several variations.
It was first described in 1920 and now affects 1/1,000,000 people a year
80% of cases occur between the ages of 50-70
death usually occurs 4-5 months after the onset of symptoms
It’s a degenerative neurological disorder that is very rare, incurable, and always fatal
•
•
•
•
•
•
•
•
•
Kuru and You
Begins with a headache and pain in the limbs
Glassy eyes/cross eyed
As it progresses, unsteady gait and incordination ; loss of balance and clumsiness
Muscle jerks and trembling spasms occur (kuru means to tremble or shiver)
Muscles spasms make victims appear to chuckle or giggle
Patients lose control of voluntary movements, such as the ability to stand
Emotional instability. Victims often become belligerent or aggressive
Damage to the muscle timing areas of the brain cause the muscles used for swallowing stop working and
speech to slur. (Many victims died of starvation).
Though mute and unable to move, victims remain cognitive and are well aware of what’s going on
•
•
•
•
•
Kuru
Kuru is a prion disease that was found in the Fore tribe of Papua New Guinea
First described in 1950, it is well known today as the disease caused by cannibalism. Kuru
probably began as a sporadic case of CJD and spread as infected brains were consumed.
This disease killed off 1/3 of the women and child population and nearly 15% of the entire
population. Death within 12-18 months after onset in adults, 3-12 months in children.
Kuru stopped spreading with the end of cannibalism, but cases occurring later proved that the
disease could stay in incubation for over 40 years
It causes significant damage to the cerebellum (which controls motor functions)
GSS and Us
•
•
•
•
•
Gradually worsening
inbalance while
walking or standing
and poor cordination
Unable to walk a
straight line without
swaggering
rigid muscle tone
and strange reflexes
Visual disturbances
(sometimes
blindness) and
deafness
involuntary
movements of the
eyes
•
•
•
•
Impaired ability to
swallow
Personality changes
(irritable, intolerant,
yet often
unexplainably
cheerful)
Progressive decrease
in intelligence and
memory loss
Eventually full blown
and progressive
dementia, caused by
deposits of gray
matter in the cerebral
cortex
•
•
•
•
•
•
GSS
Gerstmann–Sträussler–Scheinker syndrome syndrome (GSS) is a genetically inherited prion disease
Occurs 1/15,000,000, with a 50% chance of passing on the gene
This hereditary disease occurs in about 4 dozen families around the world today
GSS was the first disease to prove that the prion could be both infectious and hereditary
Usually occurs around age 50 with death occurring 2-7 years after initial symptoms
This disease causes amayloid plaque deposits, which mostly accumulate in the cerebral cortex and
the basal ganglia
FFI and a Guy
Insomnia (eventually sleep becomes impossible)
• Extreme sweating and a wildly gyrating body temperature

Muscle problems such as twitching, stiffness and spasms.
• Clumsy walking, trembling in the limbs, and involuntary muscle contraction
• Depression, m o o d changes, panic
attacks and phobias.
• Vivid dreams and hallucinations
•
Acting out and gesturing during
stupors of dreamlike states
• Lack of sleep leads to extreme
• fatigue and changes in
hormone levels (not fallowing the
circadian rhythm)
• Victims become unresponsive or
mute as dementia sets in
• Comma, followed by death
•
•
•
•
FFI
Introduced in 1986, Fatal Familial Insomnia occurs 1/33,000,000 people
It is a genetic disease, having a 50% chance of inheritance. There have been 7 reported cases of the
disease appearing sporadically without a genetic mutation.
FFI can present in two forms. In victims that have the early onset form, the symptoms are predominantly
mental. Early onset develops slower, patients can live as long as 36 months. Victims with the form that
occurs later in life, usually around age 50, experience symptoms predominately associated with insomnia.
Victims of late onset usually die within 12 months.
Damage to the anterior and dorsomedial nuclei of the thalamus is the most notable effect of FFI on the
brain. When a victim lives long enough, cerebral cortex spongiform changes also occur.
•
•
•
•
•
•
•
•
•
•
vCJD and an Entire Country
Within 4 months of the onset, poor memory and an unsteady gait develop
Unusual sensory symptoms
Jerky movements, involuntary muscle contractions, and muscle paralysis
visual deterioration and eventual blindness
slurred speech, difficulty swallowing
Incontinence
Increasingly intense hallucinations
depression, withdrawal, anxiety, trouble sleeping, and schizophrenia-like psychosis
Increasing, extreme dementia
Patients become completely immobile and mute, and eventually lapse into a coma which is fallowed by
death
•
•
•
•
•
•
vCJD
Variant Creutzfeldt-Jakob Disease is more commonly known as mad cow disease
vCJD is acquired from eating beef tainted with bovine spongiform encephalopathy (BSE).
In the 1980s BSE was found in cattle throughout Britain. Infected cattle entered the food chain and was passed
on to humans through the consumption of prion infested meat
The age of onset is typically younger than regular CJD, with an average onset at 29 years old. The duration of the
disease is usually longer than CJD, with death around 14 months of onset.
So far, most cases have occurred in the UK. By February 2009, vCJD had killed 164 people in Britain, and 42
elsewhere. This spongiform encephalopathy has also killed zoo animals, other livestock, and even household pets
that were fed infected meat
Area’s of the brain damaged by vCJD tend to be consistent with CJD’s known targets, but there are more extensive
spongiform changes. It effects hippocampus, thalamus, basal ganglia, cerebellum, and lymphatic tissue.
A Bystander Reminder
Patients aren’t the only victims of prion diseases…
CJD victim Jonathan Simms and his father Don.
conclusion
Though rare, prion disease are a force to be reckoned with. The sheer thought of something
eating brains is frightening. Many physical as well as psychological effects are experienced by
their victims, who are aware of their own state up until the end. All cases lead to death.
They leave a path of traumatized onlookers on their trail of death. They are one of the
scariest pathogens known to man, they are also one of the most interesting microbes in
existence.
Works Cited
•
Yam, Philip. The Pathological Protein. New York: Copernicus Books, 2003
•
Max, D.T. The Family That Couldn’t Sleep. Random House, 2006
•
Collins, Kumar. Robbins Pathologic Basis of Disease. Philadelphia: W.B Saunders Company, 1998
•
Rhodes, Richard. Deadly Feasts. New York: Simon & Schuster, 1997
•
“The Brain Eater”. By Joseph McMaster. Dir. Alan Ritsko. NOVA. PBS. February 10, 1998.
•
http://www.cjdfoundation.org/
•
http://www.who.int/en/
PHOTOS:
http://www.belfasttelegraph.co.uk/sunday-life/cjd-survivor-still-defying-the-odds-14121775.html
http://www.time.com/time/europe/photoessays/cjd/
http://www.biologie.uni-duesseldorf.de/Institute/Physikalische_Biologie/Research/Topics/addinformation2
http://medicalworldofmine.blogspot.com/2008/06/choosing-nursing-home-for-alzheimers.html
http://www.best-sleepaid.com/causes-of-insomnia/
Download