• Our experiments have shown that the normal prion proteins found in brain cells reduce the formation of beta-amyloid, a protein that binds with others to build plaques in the brain that are found in Alzheimer's disease,'' explains Professor Hooper. (psychcentral.com)
  • Using cells grown in the lab, the team looked at the effect of high and low levels of normal prion protein on the successful formation of beta amyloid, the source of Alzheimer's plaques. (psychcentral.com)
  • It appears that PrPc, the normal prion protein, exerts its beneficial effect by stopping an enzyme called beta-secretase from cutting up amyloid protein into the smaller beta-amyloid fragments needed to build plaques. (psychcentral.com)
  • Until now, the normal function of prion proteins has remained unclear, but our findings clearly identify a role for normal prion proteins in regulating the production of beta-amyloid and in doing so preventing formation of Alzheimer's plaques.Whether this function is lost as a result of the normal ageing process, or if some people are more susceptible to it than others we don't know yet. (psychcentral.com)
  • The next step for our research will be to look in more detail at how the prion protein controls beta amyloid, knowledge that could be used to design anti-Alzheimer's drugs. (psychcentral.com)
  • Instead, the brains contained large accumulations of prion protein plaques trapped outside blood vessels in a disease process called cerebral amyloid angiopathy. (preventdisease.com)
  • Protein aggregation and amyloid formation are central pathologic events in a wide range of neurodegenerative illnesses, including Alzheimer's, Parkinson's, and prion diseases ( 1 ). (pnas.org)
  • All known prions induce the formation of an amyloid fold, in which the protein polymerises into an aggregate consisting of tightly packed beta sheets. (wikipedia.org)
  • The summary table below, of what the two new anti-prion antibodies immuno-precipitate, is based on the highly compressed text, gel legends, illegible fax images, faulty memory of citation content, and guesswork. (mad-cow.org)
  • So, with respect to anti-prion pills, any prions that happen to become part of the diet can be destroyed before they reach the brain. (halfbakery.com)
  • Keeping cervids out of grazing or growing fields should be considered as a way to manage the risk of prions entering the human food chain. (virology.ws)
  • However, three decades of subsequent investigations, pursued most notably by Stanley Prusiner, who was awarded the Nobel Prize in Physiology or Medicine in 1997 for his work with prions and TSEs, resulted in the wide acceptance of this 'protein-only hypothesis' w2 . (scienceinschool.org)
  • The demonstration of prion secretion in sheep in a variety of matrices including milk (Maddison et al. (nottingham.ac.uk)
  • Excretion/secretion occurs through long asymptomatic periods of disease development and from sheep with a range of PRNP genotypes, including those with limited lymphoreticular involvement in prion replication (Gough et al. (nottingham.ac.uk)
  • The BSE prions concentrate in an animal's brain and spinal cord, but they been detected only in sheep blood at low concentrations. (rense.com)
  • Prions are generally transmitted from animal to animal (cow to cow, sheep to sheep). (rense.com)
  • Technical explanation of sheep and human prion proteins in normal and dimer forms. (dmoztools.net)
  • It has been known for some time that prions play a large role in molecular biology, but the transformation and replication process into rouge prions has been at the forefront of research, so this study is interesting. (metafilter.com)
  • It more accurately points to the curious role that some prions play in building neural networks and genetic replication, which has been known generally. (metafilter.com)
  • Prion structure varies slightly between species, but nonetheless prion replication is subject to epimutation and natural selection just like other forms of replication. (wikipedia.org)
  • Computer graphic showing the replication and spread of prions in cells. (dmoztools.net)
  • Without the genetic information that allows everything from viruses to human cells to replicate, scientists wondered, how could prions multiply and cause disease? (sourcewatch.org)
  • There is still a veil of mystery around prions and exactly how they replicate, cross the blood-brain barrier and cross the species barrier - i.e. infect different species of host. (scienceinschool.org)
  • There is no species barrier to prion disease. (virology.ws)
  • The most worrying prion strain is the one that causes vCJD - a form of mad cow disease that has crossed the species barrier to infect humans (see box below). (scienceinschool.org)
  • This is a list of the genera, species, and sub-species belonging to the prions, which belong to the Procellariiformes. (wikipedia.org)
  • A concern is that prions of chronic wasting disease could be transmitted to cows grazing in pastures contaminated by cervids. (virology.ws)
  • Therefore it is possible that prions excreted by deer could pass on to other animals, such as grazing cows, or even humans consuming contaminated plants (illustrated - image credit ). (virology.ws)
  • Newer regulations that govern the handling and feeding of cows may help prevent the spread of prion diseases. (hopkinsmedicine.org)
  • Stanley B. Prusiner, editor of this volume, was awarded the 1997 Nobel Prize in Physiology and Medicine for his pioneering discovery of prions. (springer.com)
  • Prusiner cited this evidence when he proposed the prion model in 1982. (encyclopedia.com)
  • After several groups determined the genetic sequence of that protein, Prusiner realized that it was a fragment of a normal protein (prion protein or PrP), the function of which is still uncertain, which is found in healthy nerve cells. (encyclopedia.com)
  • Stanley B. Prusiner, " Prion Diseases and the BSE Crisis ," Science magazine, 2003. (sourcewatch.org)
  • citation needed] In 1982, Stanley B. Prusiner of the University of California, San Francisco announced that his team had purified the hypothetical infectious prion, and that the infectious agent consisted mainly of a specific protein - though they did not manage to isolate the protein until two years after Prusiner's announcement. (wikipedia.org)
  • When deer are fed prions they excrete them in the feces before developing clinical signs of infection, and prions can also be detected in deer saliva. (virology.ws)
  • It will be interesting for the authors to follow up their EM studies on PrP to define the ultrastructural site(s) of PrP accumulation with the onset of prion pathology. (alzforum.org)
  • Importantly, their data, which appeared in the August 6 Journal of Neuroscience, show that a pool of prions exists in the neuronal cytosol, supporting a recent hypothesis that minute amounts of misfolded, cytosolic prion may be sufficient to cripple neurons. (alzforum.org)
  • For this reason, a minority of researchers still consider the prion/TSE hypothesis unproven. (wikipedia.org)
  • The study also may help to improve our understanding of such neurodegenerative diseases as Alzheimer s, in which brain cells gradually "silt up" with structures similar to the prion beta-sheet that are connected to brain cell death. (innovations-report.com)
  • Is there anyone out there who can give me a pointer to a good reference book/website/newsgroup where I would be able to get information on the primary, secondary, tertiary, and quaternary structures of any prion protein(s), or information on prions in general? (bio.net)
  • Grass plants can bind, uptake and transport infectious prions, according to researchers at The University of Texas Health Science Center at Houston (UTHealth). (medicalnewstoday.com)
  • The researchers saw signs typical of prion disease, including weight loss, lack of grooming, gait abnormalities and inactivity. (preventdisease.com)
  • Researchers at the Whitehead Institute in Cambridge, Massachusetts, US, have now found that adult stem cells in bone marrow gradually lose their ability to regenerate without their normal complement of membrane-bound prions. (newscientist.com)
  • Because the drug seems to weaken the prions' protective armor, the authors conclude that "tetracyclines are immediate candidates for prion inactivation in potentially contaminated products and prevention strategies relevant to acquired forms of disease. (scientificamerican.com)
  • The plant materials were then washed and amounts of prions were determined by protein misfolding cyclic amplification . (virology.ws)
  • Small amounts of prions were detected in stems from all plants, while 1 in 4 plants contained prions in leaves, at levels that should be able to infect an animal. (virology.ws)
  • The risk of prion transmission to biosolids from animals is low but can increase with the presence of small amounts of neural tissues or placenta coming from slaughter houses. (rense.com)
  • These refolded prions can then go on to convert more proteins themselves, leading to a chain reaction resulting in large amounts of the prion form. (wikipedia.org)
  • The prion theory was controversial at first, since other known infectious agents - bacteria, viruses, parasites and fungi - contain their own genetic information (DNA or RNA). (sourcewatch.org)
  • Nevertheless, there are still those who believe that prion diseases are actually caused by unconventional viruses and that prion proteins are just part of this mysterious virus. (scienceinschool.org)
  • This paper underscores the importance of immuno-EM in determining the subcellular localization of disease-linked peptides, and provides further parallels between prion diseases and AD, two neurodegenerative diseases associated with dementia, neuronal loss, and cerebral plaques. (alzforum.org)
  • Prion diseases should be considered in all people with rapidly progressive dementia. (hopkinsmedicine.org)
  • Since the epidemic of 'mad cow disease' in the 1980s and 90s, and the emergence of its human equivalent, variant Creutzfeld-Jacob disease, there has been a great deal of research into prions, the causative agents. (scienceinschool.org)
  • For example, prions have been found in the urine and blood of human victims of Creutzfeldt Jakob Disease. (rense.com)