Thursday, August 11, 2011
INFECTIOUS PROTEINS
A prion is an abnormal, transmissible agent that is able to induce abnormal folding of normal cellular prion proteins in the brain, leading to brain damage and the characteristics signs and symptoms of the disease. Prions are also called abnormal infectious proteins . All known prion diseases affect the structure of the brain or other neural tissue and all are currently untreatable and universally fatal.
Microscopic "holes" are characteristic in prion-affected tissue sections, causing the tissue to develop a "spongy" architecture.
About Prion Diseases
Prions cause neurodegenerative disease by aggregating extracellularly within the central nervous system to form plaques known as amyloid, which disrupt the normal tissue structure. This disruption is characterized by "holes" in the tissue with resultant spongy architecture due to the vacuole formation in the neurons. Other histological changes include astrogliosis and the absence of an inflammatory reaction.While the incubation period for prion diseases is generally quite long, once symptoms appear the disease progresses rapidly, leading to brain damage and death.Neurodegenerative symptoms can include convulsions, dementia, ataxia (balance and coordination dysfunction), and behavioural or personality changes. A vaccine has been developed in mice, however, that may provide insight into providing a vaccine in humans to resist prion infections. Additionally, in 2006 scientists announced that they had genetically engineered cattle lacking a necessary gene for prion production – thus theoretically making them immune to BSE,building on research indicating that mice lacking normally occurring prion protein are resistant to infection by scrapie prion protein.The human prion disease variant Creutzfeldt-Jakob disease, however, is believed to be caused by a prion which typically infects cattle, causing Bovine spongiform encephalopathy and is transmitted through infected meat.
Prion diseases or transmissible spongiform encephalopathies (TSEs) are a family of rare progressive neurodegenerative disorders that affect both humans and animals. They are distinguished by long incubation periods, characteristic spongiform changes associated with neuronal loss, and a failure to induce inflammatory response.
Antibodies that stick to a brain prion protein called PrP could be the key to treating prion diseases like variant CJD and preventing people accidentally exposed to prions from going on to develop the fatal brain disease. Using a precise visualisation technique, called X-ray crystallography, carried out at the Synchrotron Radiation Source (SRS) at the Science and Technology Facilities Councils (STFC) Daresbury Laboratory in Cheshire, scientists have identified an antibody that has the best ability to bind to PrP in the brain. Experiments using cells in the laboratory and in mice have suggested it could stop prion infection in its tracks.
crystallography image of prion molecule
Human Prion Diseases
Creutzfeldt-Jakob Disease (CJD)
Variant Creutzfeldt-Jakob Disease (vCJD)
Gerstmann-Straussler-Scheinker Syndrome
Fatal Familial Insomnia
Kuru
Animal Prion Diseases
Bovine Spongiform Encephalopathy (BSE)
Chronic Wasting Disease (CWD)
Scrapie
Transmissible mink encephalopathy
Feline spongiform encephalopathy
Ungulate spongiform encephalopathy
Resouorces :
http://en.wikipedia.org/wiki/Prion
http://www.cdc.gov/ncidod/dvrd/prions/
important links :
histological slide of TSE
http://www.cdc.gov/ncidod/dvrd/cjd/index.htm
http://www.cdc.gov/ncidod/dvrd/vcjd/index.htm
About Prion Diseases
Prions cause neurodegenerative disease by aggregating extracellularly within the central nervous system to form plaques known as amyloid, which disrupt the normal tissue structure. This disruption is characterized by "holes" in the tissue with resultant spongy architecture due to the vacuole formation in the neurons. Other histological changes include astrogliosis and the absence of an inflammatory reaction.While the incubation period for prion diseases is generally quite long, once symptoms appear the disease progresses rapidly, leading to brain damage and death.Neurodegenerative symptoms can include convulsions, dementia, ataxia (balance and coordination dysfunction), and behavioural or personality changes. A vaccine has been developed in mice, however, that may provide insight into providing a vaccine in humans to resist prion infections. Additionally, in 2006 scientists announced that they had genetically engineered cattle lacking a necessary gene for prion production – thus theoretically making them immune to BSE,building on research indicating that mice lacking normally occurring prion protein are resistant to infection by scrapie prion protein.The human prion disease variant Creutzfeldt-Jakob disease, however, is believed to be caused by a prion which typically infects cattle, causing Bovine spongiform encephalopathy and is transmitted through infected meat.
Prion diseases or transmissible spongiform encephalopathies (TSEs) are a family of rare progressive neurodegenerative disorders that affect both humans and animals. They are distinguished by long incubation periods, characteristic spongiform changes associated with neuronal loss, and a failure to induce inflammatory response.
Antibodies that stick to a brain prion protein called PrP could be the key to treating prion diseases like variant CJD and preventing people accidentally exposed to prions from going on to develop the fatal brain disease. Using a precise visualisation technique, called X-ray crystallography, carried out at the Synchrotron Radiation Source (SRS) at the Science and Technology Facilities Councils (STFC) Daresbury Laboratory in Cheshire, scientists have identified an antibody that has the best ability to bind to PrP in the brain. Experiments using cells in the laboratory and in mice have suggested it could stop prion infection in its tracks.
Human Prion Diseases
Creutzfeldt-Jakob Disease (CJD)
Variant Creutzfeldt-Jakob Disease (vCJD)
Gerstmann-Straussler-Scheinker Syndrome
Fatal Familial Insomnia
Kuru
Animal Prion Diseases
Bovine Spongiform Encephalopathy (BSE)
Chronic Wasting Disease (CWD)
Scrapie
Transmissible mink encephalopathy
Feline spongiform encephalopathy
Ungulate spongiform encephalopathy
Resouorces :
http://en.wikipedia.org/wiki/Prion
http://www.cdc.gov/ncidod/dvrd/prions/
important links :
histological slide of TSE
http://www.cdc.gov/ncidod/dvrd/cjd/index.htm
http://www.cdc.gov/ncidod/dvrd/vcjd/index.htm
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