Links for Keyword: Prions

Follow us on Facebook or subscribe to our mailing list, to receive news updates. Learn more.


Links 61 - 80 of 238

Old epidemic sheds new light on vCJD XAVIER BOSCH New evidence from an old epidemic could help those trying to estimate how many people may be incubating variant Creutzfeldt–Jakob disease (vCJD) - the human form of mad cow disease. So say scientists in the United States who have studied DNA extracted from victims of the first documented prion disease, kuru1. Like vCJD, kuru is a neurodegenerative disease caused by infection with a rogue 'prion' protein. The disease spread among the Fore people of Papua New Guinea in the 1940s and 1950s as a result of their cannibalistic funerary rituals. 1.Lee, H.-S. et al. Increased susceptibility to kuru of carriers of the PRNP 129 methionine/methionine genotype. Journal of Infectious Diseases 183, 192–196 (2001). © Macmillan Magazines Ltd 2001 - NATURE NEWS SERVICE Nature © Macmillan Publishers Ltd 2001 Reg. No. 785998 England.

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 189 - Posted: 06.24.2010

By Tina Hesman Saey Sea slugs make memories with a twist. Screwing a normal nerve cell protein into a distorted shape helps slugs, and possibly people, lock in memories, new research shows. Notably, the shape change also brings a shift in the protein’s behavior, leading it to form clumps. That kind of behavior is the sort seen in prions, the misshapen, infectious proteins that cause mad cow disease, scrapie and other disorders (SN: 7/31/04, p. 67). But the new study, published February 5 in Cell, shows a possible normal function for the shape-shifting, suggesting that twists and clumps don’t necessarily make prions monsters. In one sense, prions are machines of “molecular memory,” says Yury Chernoff, a biologist at the Georgia Institute of Technology in Atlanta and editor in chief of the journal Prion. The proteins remember what happened to them — changing shapes — and then transmit that change to other proteins. “But the notion of these machines being used for cellular, and therefore organismal, memory is truly amazing,” he says. If further research shows the process works the same way in humans as it does in sea slugs, prionlike proteins might eventually be used in memory-enhancing treatments, Chernoff says. Prions have a bad reputation due to the most famous of the shape-changing proteins, called prion protein or PrP. When PrP switches from its harmless form, which is normally present in nerve cells, into a prion form, it corrupts other PrP molecules that then assemble themselves into nearly indestructible plaques known as amyloids. © Society for Science & the Public 2000 - 2010

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders; Chapter 13: Memory and Learning
Link ID: 13747 - Posted: 06.24.2010

By Carina Storrs When prions are transferred from one species to another—like from sheep and cows to mice in the laboratory or to humans in the case of the fatally neurodegenerative variant Creutzfeldt-Jakob disease—new forms of the infectious proteins can emerge over time that make them deadly to the new host. A new study examines the emergence and persistence of prion mutations, which allow prions to grow in infected cells in the presence of anti-prion compounds. In the classic sense, prions, which are misfolded versions of the brain protein PrP, cannot mutate because they do not contain DNA or RNA. They can, however, give rise to variants with different properties, possibly due to differences in the folding, or shape, of the proteins. In the study, published December 31 in Science Express, researchers estimated the rate at which prion mutants can appear in cultured human nerve cells. In addition, the study suggests that once variants appear, they persist at low levels, giving rise to a heterogeneous prion population. "On the face of it, you have exactly the same process of mutation and adaptive change in prions as you see in viruses," said Dr. Charles Weissmann in a prepared statement. Weissmann, who is the head of the Scripps Florida Department of Infectology in Jupiter, Fla., led the study. To track prion mutation, Weissmann's team mixed one prion-infected human nerve cell with 1,000 uninfected human nerve cells in each petri dish. The infected cell contained a single prion that was susceptible to a drug called swainsonine, or swa. © 1996-2010 Scientific American

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 13621 - Posted: 06.24.2010

A group of German researchers may have figured out why a protein that can turn rogue and cause fatal illnesses such as mad cow disease exists in large quantities inside cows, humans and other animals. The protein — known as the "prion" protein or PrP — appears to help cells communicate with each other when an embryo is developing, said a paper published Monday in the journal PloS Biology by a group of researchers at University of Konstanz in Germany. "What we see PrP doing in the fish embryo … may be analogous to what it does in the mammalian brain, which is what may go wrong during prion diseases," biologist Edward Malaga-Trillo, who led the study, said in an email to CBCNews.ca. Diseases such as mad cow disease in cows and Creutzfeldt-Jakob disease in humans have been traced back to rogue, altered versions of the prion protein. But up until now, researchers have been unsure what normal versions of the protein are supposed to do. Those normal proteins are the "starting ingredient" for prion diseases. When prion proteins fold abnormally, they clump together into groups called plaques that lead to brain damage. The misfolded prions multiply by turning normal prions "bad." In previous studies, mice engineered so they were unable to produce the normal prion protein seemed mostly normal. However, in the recent study led by University of Konstanz biologist Edward Malaga-Trillo, zebrafish embryos that could not make the prion protein didn't develop normally and eventually died. © CBC 2009

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 12634 - Posted: 06.24.2010

By DONALD G. McNEIL Jr. D. Carleton Gajdusek, a virologist who won the 1976 Nobel Prize in medicine for his work on the mysterious epidemics now known as prion diseases, died last week in Tromso, Norway. The cause of death is unknown, but Dr. Gajdusek (pronounced GUY-dah-shek) was 85 and had long had congestive heart failure, said Dr. Robert Klitzman, his biographer, who said he had spoken to him about a week ago. He was found in his Tromso hotel room on Friday morning about 24 hours after a manager saw him at breakfast. In later life, Dr. Gajdusek became notorious when he was charged with molesting the many young boys he had adopted in New Guinea and Micronesia and brought to live with him in Maryland. He pleaded guilty to one charge, served a year in prison and left the United States in 1998, dividing his time between Paris, Amsterdam and Tromso. Dr. Gajdusek won the Nobel for his work on kuru, which was slowly wiping out the Fore tribe of New Guinea. Victims descended into trembling and madness before death and, after an autopsy, were found to have brains shot through with spongy holes. In 1957, Dr. Gajdusek — who had searched the Hindu Kush, the Amazon jungle and finally the mountain valleys of New Guinea hoping to find remote tribes with unique diseases to study — realized that the victims had all participated in “mortuary feasts” in the decades before the custom was suppressed in the 1940s by missionaries and the Australian police. Copyright 2008 The New York Times Company

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 12338 - Posted: 06.24.2010

Prions have traditionally been linked with the development of Creutzfeld-Jakob Disease (CJD), the brain-wasting equivalent of mad cow disease (also known as bovine spongiform encephalopathy). (CBC)Prions — infectious agents that cause diseases like the human variant of mad cow disease — also have protective properties, new research suggests. When functioning normally, prion proteins protect neurons in the brain from becoming overstimulated and dying, indicates the study, published in the May 5 issue of the Journal of Cell Biology. Prions have traditionally been linked with the development of neurodegenerative diseases like Creutzfeld-Jakob Disease (CJD), the brain-wasting equivalent of mad cow disease (also known as bovine spongiform encephalopathy, or BSE). In this role, abnormal prions cause plaques to form on the neurons preventing them from functioning properly. Researchers at Rockefeller University discovered that when they removed prion proteins from the brain cells of mice, their neurons overreacted to electrical and drug-induced stimulation, eventually dying. The authors believe that prion proteins only turn deadly when they are physically altered, as they can no longer regulate the behaviour of the neurons and offer a neuroprotective effect. Researchers aren't sure how this transformation occurs. © CBC 2008

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 11611 - Posted: 06.24.2010

Nathan Seppa Mad cow disease and other brain disorders stemming from prion proteins have long resisted cure. Now, in a test in mice, a prion disease caught early has been reversed. Prions—misfolded versions of a natural protein called PrP—trigger normal PrP to misfold in the same way. Over time, prion infection kills so many neurons that the brain becomes riddled with holes. In the new study, neurologist Giovanna R. Mallucci of the Institute of Neurology in London and her colleagues tested whether shutting off the prions' supply of PrP could alter the course of disease. They worked with genetically engineered mice that make PrP only for the first 9 weeks of life and normal mice that make PrP indefinitely. The researchers infected both groups, shortly after birth, with prions that cause scrapie in sheep. At 8 weeks of age, mice in both groups showed cognitive deficits. For example, mice normally spend more time exploring unfamiliar sets of objects than known ones. But the infected mice spent the same time examining strange or familiar arrangements of blocks, indicating that the animals had forgotten familiar arrangements. The mice also lost some of their natural inclination to gather food pellets. ©2007 Science Service.

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 9918 - Posted: 06.24.2010

Heidi Ledford A man walks around the neighbourhood with his family, and stops to admire a particularly lovely house. He turns to his family and asks who built it. "You did," they reply. It was the first sign that something was wrong, he would later recount to researchers at the University of California, San Francisco. But it was another half a year before he developed the classical erratic behaviour and unsteady gait typical of Creutzfeldt-Jakob disease (CJD) — a neurodegenerative condition caused by an infectious protein called a prion. A diagnosis of CJD is a death sentence, and researchers around the world are looking for a cure. But that cure is unlikely to do much good if doctors can't diagnose the condition in its early stages, before the patient develops severe brain damage. Now, researchers have characterized the early signs of a similar prion disease in mice. In results presented this week in Neuron1, the researchers show that shutting off production of the pathogenic protein during these early stages allowed mice to not only survive, but also recover normal brain function. ©2007 Nature Publishing Group

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 9906 - Posted: 06.24.2010

Paul Elias, Associated Press — Scientists have genetically engineered a dozen cows to be free from the proteins that cause mad cow disease, a breakthrough that may make the animals immune to the brain-wasting disease. An international team of researchers from the U.S. and Japan reported Sunday that they had "knocked out" the gene responsible for making the proteins, called prions. The disease didn't take hold when brain tissue from two of the genetically engineered cows was exposed to bad prions in the laboratory, they said. Experts said the work may offer another layer of security to people concerned about eating infected beef, although though any food derived from genetically engineered animals must first be approved by the Food and Drug Administration. "This research is a huge step forward for the use of animal biotechnology that benefits consumers," said Barbara Glenn of the Biotechnology Industry Organization, a Washington industry group that includes the company that sponsored the research as a member. "This a plus for consumers worldwide." The surviving cows are now being injected directly with mad cow disease, known as bovine spongiform encephalopathy, or BSE, to make certain the cattle are immune to it. © 2006 Discovery Communications Inc.

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 9799 - Posted: 06.24.2010

Lauran Neergaard, Associated Press — Deer probably spread a brain-destroying illness called chronic wasting disease through their saliva, concludes a study that finally pins down a long-suspected culprit. The key was that Colorado researchers tested some special deer. Chronic wasting disease is in the same family of fatal brain illnesses as mad cow disease and its human equivalent. There is no evidence that people have ever caught chronic wasting disease from infected deer or elk. But CWD is unusual because, unlike its very hard-to-spread relatives, it seems to spread fairly easily from animal to animal. Scientists were not sure how, primarily because studying large wild animals is a logistical nightmare. The sheer stress of researchers handling a deer caught in the wild could kill it. Likewise, animals deliberately exposed to infections must be kept indoors so as not to spread disease, another stress for deer used to roaming. So Colorado State University researcher Edward Hoover turned to fawns hand-raised indoors in Georgia, which has not experienced chronic wasting disease. © 2006 Discovery Communications Inc.

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 9442 - Posted: 06.24.2010

By DONALD G. McNEIL Jr. The long lives that some former cannibals enjoy before succumbing to a brain-wasting disease suggest that many more humans will eventually die of mad cow disease, scientists said Thursday. But several experts in such illnesses, called prion diseases — which are blamed for killing New Guinea cannibals and British eaters of infected beef — disagreed with that frightening implication of the study, which is to be published Friday in The Lancet, a British medical journal. These experts praised the rigorous work the authors of the report did to confirm that kuru, a disease that once decimated highland tribes in New Guinea, can incubate for 50 years in a few genetically protected people. But the experts said they thought that the findings did not prove that there would be future waves of deaths among people who ate beef from prion-infected cows in the 1980's. "That's a provocative conclusion, but I'm not sure it's totally plausible," said Dr. David Westaway, a prion expert at the University of Toronto. Thus far, only about 160 people, mostly in Britain, have died of variant Creutzfeldt-Jakob disease, which humans get from cows that had bovine spongiform encephalopathy, or mad cow disease.

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 9045 - Posted: 06.24.2010

Abnormal prion proteins are little understood disease agents involved in causing horrific brain-wasting diseases such as Creutzfeldt-Jacob disease in people, mad cow disease in cattle and chronic wasting disease in deer and elk. Now, new research suggests that a variant form of abnormal prion protein — one lacking an “anchor” into the cell membrane — may be unable to signal cells to start the lethal disease process, according to scientists at the Rocky Mountain Laboratories (RML), part of the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health. “This work provides novel insights into how prion and other neurodegenerative diseases develop and it provides tantalizing clues as to how we might delay or even prevent such diseases by preventing certain cellular interactions,” notes NIAID Director Anthony S. Fauci, M.D. A paper describing the research was released online today by the journal Science. Drawing on experimental concepts first developed at RML a decade ago, the research team exposed two groups of 6-week-old mice to different strains of the agent that causes scrapie, a brain-wasting disease of sheep. Within 150 days of being inoculated with the natural form of scrapie prion protein, all 70 mice in the control group showed visible signs of infection: twitching, emaciation and poor coordination. In contrast, the scientists observed 128 transgenic mice — those engineered to produce prion protein without a glycophosphoinositol (GPI) cell membrane anchor — for 500 to 600 days and saw no signs of scrapie disease. Subsequent electron microscopic examinations at UCSD, however, confirmed that they produced amyloid fibrils, an abnormal form of prion protein, and that they even had brain lesions. More remarkably, according to Dr. Chesebro, the diseased brain tissue resembled that found in Alzheimer’s disease rather than in scrapie.

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 7445 - Posted: 06.24.2010

Nathan Seppa Even as scientist Stanley B. Prusiner was accepting a Nobel prize in 1997 for linking misfolded proteins to certain brain diseases, doubters were pointing out that no one had ever actually shown that these proteins—which Prusiner dubbed prions—could cause infection. Prusiner, a neurologist and biochemist at the University of California, San Francisco (UCSF), and his colleagues now report results that could silence many of his critics. The study, published in the July 30 Science, shows that purified prions can cause disease when injected into the brains of genetically engineered mice. Previous work by Prusiner and others had implicated prions in human-brain ailments that include Creutzfeldt-Jakob disease and kuru, as well as mad cow disease, chronic wasting disease in deer and elk, and scrapie in sheep. Suggesting that proteins, misfolded or not, can be infectious is "a radical notion," says Neil R. Cashman of the University of Toronto. Nevertheless, to Cashman and others, the new research supplies the proof. Copyright ©2004 Science Service.

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 5915 - Posted: 06.24.2010

Paul Brown In December 2003, the U.S. Department of Agriculture discovered a case of bovine spongiform encephalopathy (BSE), often called mad-cow disease, in a dairy cow from Washington state. The news was more than a little disturbing to the American cattle industry. The mad-cow scare had previously devastated the cattle business in the few countries where BSE had been reported, especially Great Britain and Canada. The Canadian cattle industry has yet to recover from the discovery of BSE in a single cow on an Alberta farm in May of last year. A 400-kilogram cow that used to fetch 500 Canadian dollars on the open market now sells for as little as 79 Canadian cents—less than the price of a fast-food burger. The economic fallout is, of course, a consequence of the discovery in 1996 that mad-cow disease could cross the species barrier to inflict human beings with variant Creutzfeldt-Jakob disease (vCJD). This disease is characterized by a progression of psychiatric and neurological symptoms that culminate in death, usually a year or two after the onset of the first indications of illness. As of May 2000, a total of 155 cases of vCJD had been identified: 144 in Great Britain (where the outbreak began), 6 in France, 1 in Ireland, and 1 in Italy. Additional single victims in Hong Kong, Canada and the U.S. were infected in the U.K., where they had been residing during the years of peak risk, in the late 1980s or early 1990s. The extraordinary commercial and public-health consequences of BSE, as well as the near-global distribution of products derived from cattle, have generated a considerable amount of attention from industry, government and the general public. As a result, there is a daunting volume of information—not all of it reliable—surrounding the nature of mad-cow disease. © Sigma Xi, The Scientific Research Society

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 5640 - Posted: 06.24.2010

By THE ASSOCIATED PRESS WASHINGTON, — Canadian officials have traced to two mills the feed that probably caused North America's two cases of mad cow disease, one in Canada last May and the other in the United States in December. The feed from the Canadian mills could have contained infectious protein from imported British cattle, said Dr. George Luterbach, an official of a mad cow working group in the Canadian Food Inspection Agency. Canadian law prohibits disclosing the identity of the mills, Dr. Luterbach said. Canada reported its only case of the disease, also known as bovine spongiform encephalopathy, or B.S.E., in an animal on a farm in Alberta. The United States followed with an announcement that a cow in Mabton, Wash., had the disease. Both animals had been raised on farms in Alberta, and both ate feed containing meat and bone meal while they were calves. Copyright 2004 The New York Times Company

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 5161 - Posted: 06.24.2010

By DONALD G. McNEIL Jr. The government has begun a criminal investigation into whether documents were falsified in the lone case of mad cow disease found in the United States, the Agriculture Department's inspector general said yesterday. The official, Phyllis K. Fong, told a House appropriations subcommittee that the investigation focused on whether the Holstein dairy cow was a "downer" — a cow too sick or injured to walk — when it was slaughtered on Dec. 9 at Vern's Moses Lake Meats in Washington State. The inquiry was "based on allegations that were reported in the media in early February concerning possible alteration of official records," Ms. Fong said. She declined to identify any targets of the investigation. Copyright 2004 The New York Times Company

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 5079 - Posted: 06.24.2010

By DONALD G. McNEIL Jr. A new form of mad cow disease has been found in Italy, according to a study released yesterday, and scientists believe that it may be the cause of some cases of human brain-wasting disease. While the strain has been found in only two Italian cows, both apparently healthy, scientists in Europe and the United States said it should provide new impetus in Washington for the Department of Agriculture to adopt the more sensitive rapid tests used in Europe because it may not show up in those used in the United States. Along with the Italian study, there have been recent reports of unusual types of mad cow disease in France and Japan, and scientists say the discovery of new forms suggests that many cases of "sporadic" human disease — by far the most common kind, responsible for about 300 deaths a year in the United States — are not spontaneous at all, but come from eating animals. Copyright 2004 The New York Times Company

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 4986 - Posted: 06.24.2010

By ALICIA AULT SILVER SPRING, Md., — Joining a growing chorus, federal advisers on Friday urged the government to increase testing for mad cow disease greatly to better gauge if the United States has a problem, and if so, how widespread it is. The panelists said that without that data, there was no way to minimize the risk to humans who might be exposed by eating meat, or through drugs, vaccines, cosmetics and dietary supplements that contain raw materials from cattle. "We have to know what the risk is, and whether we could contain it or whether we could stop it," said Dr. Stephen DeArmond, a member of the Food and Drug Administration panel, which met here on Thursday and Friday. Dr. DeArmond is a mad cow disease expert at the University of California, San Francisco. Copyright 2004 The New York Times Company

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 4970 - Posted: 06.24.2010

By SANDRA BLAKESLEE — If Americans develop a disease like the human form of mad cow that worries millions of Europeans, Dr. Pierluigi Gambetti may be the man to find it. Dr. Gambetti, an Italian neuropathologist whose mild manner and penchant for cardigan sweaters make him look a bit like Mr. Rogers, is director of the National Prion Disease Pathology Surveillance Center at Case Western Reserve University here. For the last five years, he and his staff have been collecting brain tissue from people all over the country who die from mysterious, rapidly progressive neurological disease. Now that the first case of a cow infected with mad cow disease has been discovered in the United States, Dr. Gambetti's work has taken on new urgency. Copyright 2004 The New York Times Company

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 4865 - Posted: 06.24.2010

By MATTHEW L. WALD and ERIC LICHTBLAU WASHINGTON, — A sick cow slaughtered about two weeks ago near Yakima, Wash., has tested positive for mad cow disease in early laboratory results, the first such case in the United States, the secretary of agriculture said on Tuesday. Shortly after the announcement, Japan said it was banning imports of American beef. The South Korean agriculture ministry said in a statement that South Korea was also halting American beef imports and that it was pulling American beef products off supermarket shelves. [On Wednesday morning, Russia, Thailand and Hong Kong also announced that they too were banning imports of American beef products.] Copyright 2003 The New York Times Company

Related chapters from BN: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 4734 - Posted: 06.24.2010