Prion Diseases
Abstract
Transmissible spongiform encephalopathies (TSEs) are neurodegenerative diseases that are thought to be caused by the misfolding of prion proteins. Prions are able to replicate in the absence of nucleic acids. TSEs include: scrapie, bovine spongiform encephalopathy, Creutzfeldt-Jakob disease, kuru, Gerstmann-Straussler-Scheinker disease, and Fatal Familial Insomnia. They can affect many different animals, including humans. Currently, there are no ways to diagnose, treat, or cure TSEs, as much more research is needed before these diseases are completely understood.
1. Overview
Prions are a type of protein found naturally in the brain and other regions of the central nervous system. The diseases associated with prions are collectively known as transmissible spongiform encephalopathies (TSEs). “Transmissible” refers to their potentially infectious nature, and “spongiform encephalopathies” indicates the microscopic sponge-like deterioration of the brain caused by the progression of the disorders. While these fatal neurodegenerative diseases exhibit different clinical symptoms, have different incubation periods, and even target different areas of the brain, they do share a number of characteristics. They occur in both animals and humans. During a silent incubation period, there are no detectable signs of the disease, although depending on the specific disease, the length of the incubation period can “vary from a few weeks to up to 40 [years]” (Baker & Ridley, 1996, 1). Due to their unique method of propagation (which will be addressed later), TSEs present a seeming paradox in that “inherited cases give rise to a disease that is transmissible but acquired cases do not produce heritable diseases” (Baker & Rid...
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...(Soto, 2006, 105).
15. Conclusion
On a closing note, prion research is significant not only for possible breakthroughs in understanding TSEs, but because of the vast implications the very concept of prions holds for the entire field of biology. As the first substance discovered that can replicate in the absence of nucleic acids, prions defy one of the most central biological doctrines. The similarities between TSEs and dementia disorders like Alzheimer’s disease and “findings of proteins with a prion-like behavior in yeast and other fungi” (Soto, 2006, 143) suggest that prions and proteins like them may be much more common than ever expected (Soto, 2006, 154).
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Bibliography
Baker, Harry F., & Ridley, Rosalind M. (1996). Prion Diseases. Totowa, New Jersey: Humana
Press.
Soto, Claudio. (2006). Prions: The New Biology of Proteins. Boca Raton, Florida: CRC Press.
Mad Cow Disease, scientifically referred to as (BSE) Bovine Spongiform Encephalopathy, is a disease that affects those humans who eat the meat from infected cows. Mad Cow Disease is one of several fatal brain diseases called (TSE) Transmissible Spongiform Encephalopathy. (USDA) There was evidence of a new illness resembling the sheep disease scrapie. It was technically named BSE but quickly acquired the mad cow tag because of the way infected cattle behave. (CNN) In 1997, there was an award given to Stanley Prusiner, for concluding that a distorted protein called a prion was responsible for Mad Cow Disease, noted the long incubation period made it difficult to distinguish (Bryant). Another name for Mad Cow Disease is the new variant Cruetzfeldt-Jakob Disease (vCJD), similar to the Creutzfeldt-Jakob Disease, which is a deadly brain illness that strikes about one per million per year (USDA) due to genetic or unknown causes while the vCJD is contracted from eating infected cows (USDA). Both CJD and vCJD are so similarly named because of the similar effects from the illness.
Mad cow disease is caused by prions, "weird mutant proteins that are found in brain and spinal tissue"1. Another name for mad cow disease is called bovine spongiform encephalopathy (BSE) and the definition is "a progressive neurological disorder of cattle that results from infection by an unusual transmissible agent called a prion"2. It started from what is called a prion protein then it turned into a pathogenic, and then it starts to damaged the brain of a cattle. There's another name for this disease and it's called Creutzfeldt-Jakob Disease "a form of progressive dementia characterized by loss of nerve cells and degeneration of nerve cell membranes leading to the production of small holes in the brain. It is rare, degenerative, and invariably fatal"3. This disease happen in human causing lapses in the memory, mood swings similar to depression, lack of interest and social withdrawal3. It is said that this disease has no tr...
Creutzfeldt-Jakob is known as a prion disease. Prion is a protein that occurs normally inside the brain, however
Neurodegeneration is used mainly for diseases that are characterised by progressive loss of structure and function of neurons. There are many neurodegenerative diseases including amyotrophic lateral sclerosis that...
The origin of CWD has yet to be determined (Sigurdson & Aguzzi, 2007). The infection was first noted in 1967 at a captive mule deer research facility. In 1978 pathologists recognized the TSE type brain lesions, also that CWD presented as a prion disease by the neuronal perikaryonic vacuoles, the accumulation of aggregated prion protein and prion infectivity in the brain. In the late 1970s and early 1980s the infection w...
TSEs or more commonly prion diseases are a group of invariably fatal neurodegenerative diseases that occur in humans and animals . This disease is caused by a protease –resistant protein (PrPsc) after misfolding of a host-encoded prion protein (PrP). TSEs can exist as genetic, infectious or sporadic forms. The diseases are characterized by dementia, ataxia and neuropathlogically due to loss of specific neurons in the brain. Other clinical features include persistent painful stimuli, dystonia, visual or cerebellar problems and gliosis (1).
Autopsies of affected cattle reveal holes in the brain tissue that give it a spongy, or spongiform, texture. Similar spongiform diseases have been recognized in humans (for example, Creutzfeldt-Jakob disease or CJD) for over a century and in sheep (scrapie) for over 200 years. The cause of BSE is unproven, although there is strong evidence that prions, which may be infective proteins, are the agent. Other hypotheses suggest that prions work with an as yet undetected virus to cause the infection.
The prion diseases that Chronic Wasting Disease is related to are Creutzfeldt-Jakobs disease found in humans, bovine spongiform encephalopathy (BSE) in cattle, and scrapies in sheep (3,4). These diseases are grouped together because they share certain characteristics such as long incubation periods, spongiform changes that are associated with neural loss, and cause failure to induce inflammatory responses (Chronic Wasting Disease Alliance).
Prions are pathogens, and cause infections, like viruses. Prions cause many neurodegenerative diseases, but are made up of harmless proteins found in mammals and birds. The proteins are not in their normal form though, and once they enter the human brain, can cause severe brain infections. One thing that makes them different from viruses, is the lack of nucleic acids, which means they have no genetic code. Once in the brain, they make normal proteins turn into abnormal ones, which then multiply, causing severe infection. Soon, holes appear in the brain that can only be treated by incineration. An example of a disease caused by a prion would be the Mad Cow Disease, or the human equivalent Creutzfeldt–Jakob disease. Prions are very dangerous. While some people can confuse prions and viruses, there are some ways to tell the difference.
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Creutzfeldt-Jakob Disease is an uncommon, deteriorating, consistently fatal brain disorder that is caused by prions. The symptoms of CJD are similar of Alzheimer’s but progress much faster. There are three variations of CJD, sporadic, familial, and acquired. All variations affect the brain the same way and have the same result of death. CJD is an untreatable and incurable disease.
James Parkinson first discovered Parkinson's Disease in 1817. Parkinson's Disease is a common neurologic disorder for the elderly. It is a disorder of the brain characterized by shaking and difficulty with walking, movement, and coordination. This disease is associated with damage to a part of the brain that controls muscle movement. Parkinson's Disease is a chronic illness that is still being extensively studied.
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