Links for Keyword: Prions

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In 1997 a cloned sheep named Dolly brought the issue of cloning to the public's attention. Then it was quickly proven that other animals, including pigs and cows, could also be cloned. But, it still had to be proven that it was safe to consume products from cloned animals. In a study published in 2005 in Proceedings of the National Academy of Sciences, Xiangzhong "Jerry" Yang, director of the Center for Regenerative Biology at the University of Connecticut, found that meat from two cloned bulls and a thousand samples of milk from cloned Holstein Dairy Cows meet industry standards for beef and milk from naturally produced cattle. The study was more than just curiosity, because as Yang points out, "One of the applications for cloning farmed animals, including cattle, pigs is really for improving agriculture, for better milk production, for better meat production." But, until the FDA approval, no country had allowed consumption or marketing of products from cloned animals. Yang says cloning cattle could improve agricultural efficiency. "If we can clone highly producing top genetic cows in the U.S. or for developing countries, we actually can increase the number of animals for high-level production. Or, if you have enough milk already, you can reduce the number for the same amount of milk production." © ScienCentral, 2000-2007.

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
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Link ID: 9803 - Posted: 06.24.2010

Michael Hopkin A US-led research team has developed a technique to filter potentially deadly prion proteins from blood. They suggest that the method should be used routinely in attempts to remove prions, which can cause variant Creutzfeldt-Jakob disease (vCJD), from blood products used for transfusions. The method could offer better protection than the current practice of removing white blood cells from donated blood, say the researchers, led by Robert Rohwer of the University of Maryland, Baltimore. Previous studies have shown that around a half of the abnormal, infective prion proteins are in white blood cells, so removing these can help reduce the risk of infection. But infective prions are also found in the blood plasma. Of the 200 vCJD cases recorded worldwide, only a few have involved contaminated blood transfusions, but health officials are still worried about this possible transmission route. Several countries have banned blood donations from people who have lived in Britain, where many people have potentially eaten meat containing infective prions. Despite the relatively few cases of this devastating, untreatable disease, researchers worry that many other people might be carriers. According to a survey of samples from tonsil and appendix removals, as many as 4,000 British people may be harbouring the disease, which can remain dormant for decades, without showing symptoms. There is currently no test to detect abnormal prions in humans, meaning that it is impossible to identify these people. ©2006 Nature Publishing Group

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 9780 - Posted: 06.24.2010

By Katherine Unger The proteins that, when mangled, cause "Mad Cow" and similar diseases also help regulate how yeast cells metabolize metals, biochemists report. Exposure to high levels of metals can coax proteins called prions to adopt an abnormal disease-causing conformation, the researchers found. That could explain why outbreaks of prion diseases have popped up in Iceland, Slovakia, and Colorado--regions with soils high in manganese. Mad Cow disease in cattle, scrapie in sheep, and Creutzfeldt-Jakob disease in humans are all deadly and transmissible conditions in which the brain degenerates. All seemed to be caused by prion proteins that have changed shape so that enzymes can no longer break them down. This altered conformation is widely thought to be responsible for the diseases, because the tangled and essentially indestructible proteins collect in brain tissue (ScienceNOW, July 29 2004). Studies have shown that some metals bind to prion proteins, leading some scientists to wonder whether metals are involved in the shape shift. Now, biochemist Gerd Multhaup of the Free University of Berlin and colleagues have shown that prions alter metal metabolism in yeast. As a first step, they took a species of yeast that does not normally make prions and added prions that don't cause disease. Copper levels increased 1.6-fold inside these cells while manganese decreased by half compared to yeast without prion proteins, the researchers report in a paper to be published 13 June in Biochemistry. The researchers then added copper or manganese to the growth medium to form 1 to 5 millimolar concentrations; both additions transformed the prions to the indestructible form. © 2006 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 8995 - Posted: 06.24.2010

The deadly human form of mad cow disease, vCJD, may have infected far more people than previously thought, suggests a new study. The assumption that most people are genetically shielded from the devastating disease could be wrong, said the research published on Friday. But it cautions that the evidence for this remains sketchy. Variant Creutzfelt-Jakob disease (vCJD) is linked to eating meat infected with bovine spongiform encephalopathy (BSE), also known as mad-cow disease. A rogue version of a prion protein proliferates in the brain, leading to distressing mental deterioration, loss of motor control, and eventually death. After vCJD was first identified in March 1996, some experts calculated it could inflict a death toll in the tens of thousands, especially in the UK, where the outbreak began. But these calculations were swiftly revised downwards to a few hundred or even fewer when it was realised that the toll was rising far slower than expected. At present, the UK has recorded 161 definite and probable cases of vCJD, six of whom are still alive. One reason for optimism about the potential extent of the vCJD epidemic has been the assumption that it is genetic. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 8939 - Posted: 06.24.2010

Andreas von Bubnoff The inflamed mammary glands of sheep have been found to contain protein particles that cause scrapie, a sickness similar to mad cow disease. This suggests that the suspect proteins, called prions, may also be present in the milk of infected animals. If prions exist in the milk of cows infected with both an inflammatory illness and mad cow disease, formally known as bovine spongiform encephalopathy (BSE), this raises concerns for human health. Consumption of prion-contaminated meat from cows with BSE is believed to cause the fatal variant Creutzfeldt-Jakob disease (vCJD) in people; so might contaminated milk. Adriano Aguzzi, the lead researcher on the study, has not detected prions in milk itself, because it is difficult to analyse for the abnormal proteins. But he says he expects to find them. "It is unlikely that the prions are not in the milk," says Aguzzi, a pathologist at the University of Zurich Hospital, Switzerland. "And the prospect is not a pleasant one." ©2005 Nature Publishing Group

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 8108 - Posted: 06.24.2010

Andreas von Bubnoff The protein particles that cause illnesses such as mad cow disease can be found in the urine of infected mice, researchers report. Their study may solve the mystery of how such 'prion' diseases spread among animals such as sheep, elk and deer. But it also raises concerns that the urine of humans with new-variant Creutzfeldt-Jakob disease (vCJD) may contain dangerous proteins. Prions are primarily found in the brain, the spinal cord and the immune system. British cows are thought to have developed the prion disease bovine spongiform encephalopathy (BSE) by eating ground-up brains, spleens and similar material. Other body parts were thought to be relatively safe for consumption. Then, in 2003, Adriano Aguzzi's group at the University Hospital of Zurich, Switzerland, found prions in the muscle tissue of people who had died from a brain wasting disease. And this January, the team showed in mice that prions also spread to the pancreas, kidneys and liver if there is inflammation in these organs. Together, these findings suggested that the brain and lymphatic organs might not be the only dangerous ones. ©2005 Nature Publishing Group

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 8031 - Posted: 06.24.2010

CBC News A new and disturbing theory about the possible origin of "mad cow" disease has been published, and a Canadian scientist said it is "plausible." In a report in the British medical journal, The Lancet, Professor Alan Colchester of the University of Kent in England says BSE (bovine spongiform encephalopathy) may have been caused by the tonnes of animal bones and other tissue imported in the '60s and '70s from India for animal feed which also may have contained the remains of humans infected with Creutzfeldt-Jakob disease (CJD). Colchester, and his daughter Nancy, from the college of medicine and veterinary medicine at the University of Edinburgh in Scotland, said the practice may still be taking place elsewhere. They said it is important to discover whether other countries are importing animal byproducts contaminated with human remains that are destined for feed mills. The authors admitted their hypothesis is based on a compilation of circumstantial evidence. They wrote: "We do not claim that our theory is proved, but it unquestionably warrants further investigation." It had previously been thought that the brain-wasting mad cow disease passed to cattle through remains of sheep infected with scrapie -- the sheep equivalent of BSE -- that were added to cattle feed. Copyright © CBC 2005

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 7871 - Posted: 06.24.2010

Roxanne Khamsi When it comes to deadly protein clusters in the brain, size matters. The human equivalent of mad cow disease, variant Creutzfeldt-Jakob disease (vCJD) is thought to be caused by misshapen proteins, known as prions, that infect the brain. Research now shows that the most infectious strings of prions are of a middling length; clumps that are longer or shorter are less problematic. The findings, reported in this week's Nature1, could convince medical experts to rethink how they plan to treat illnesses such as vCJD, as well as Alzheimer's and Parkinson's. Researchers have often debated whether longer or shorter chains of prions are more problematic. The molecules seem to multiply by converting the normal proteins that they touch to an irregular form. Long ones form visible tangles in the brain, but short ones might be more capable of spreading the infection. Jay Silveira and his colleagues at the Rocky Mountain Laboratories in Hamilton, Montana, obtained misshapen prion proteins from hamsters, broke them up using a detergent, and sorted them according to size. They then injected strings of known length into other hamsters. ©2005 Nature Publishing Group |

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 7868 - Posted: 06.24.2010

Roxanne Khamsi Human remains in cattle feed could have caused the first case of mad cow disease, two UK researchers propose. The hypothesis seeks to answer lingering questions about the fatal infection, which has affected 180,000 cows in Britain alone since the mid-1980s, and has gone on to cause more than 100 deaths in humans. Alan Colchester of the University of Kent and his daughter Nancy Colchester, of the University of Edinburgh, point out that during the 1960s and 1970s Britain imported hundreds of thousands of tonnes of whole and crushed bones and animal carcasses. These were used for fertilizer and to feed livestock. Nearly 50% of these imports came from Bangladesh, where peasants gathering animal materials may have also picked up human remains, the researchers say. Other experts in the field view the idea with scepticism, saying that proof remains circumstantial. "The argument isn't very compelling because there's no smoking gun evidence," says Surachai Supattapone, an expert in infectious diseases at Dartmouth Medical School in Hanover, New Hampshire. ©2005 Nature Publishing Group

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 7834 - Posted: 06.24.2010

Roxanne Khamsi For years, experts have feared that thousands of people are unknowingly carrying and transmitting the human form of mad cow disease: new-variant Creutzfeldt-Jakob disease (vCJD). Now a blood test could help to ease their worries, or confirm their worst nightmare. Researchers have succeeded in reliably detecting the malformed proteins that cause vCJD in blood samples taken from hamsters. Their test takes only a few days to complete. If the procedure works as well in humans, it could be used to check stocks in blood banks. At the moment there is no such screening process; two of the people who have died of vCJD in Britain are thought to have picked up the disease from transfusions. If improved, the test might also be used to screen animals for the disease before they enter the food chain. The rare disease is thought to be caused by the formation of abnormal proteins in the brain known as prions. These misshapen proteins apparently multiply by changing the conformation of normal proteins that they come into contact with, eventually leading to a fatal neurodegenerative illness. ©2005 Nature Publishing Group

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 7810 - Posted: 06.24.2010

By Marc Kaufman, Washington Post Staff Writer New tests have confirmed that a Texas animal that federal officials earlier declared to be free of mad cow disease did have the brain-wasting ailment, the U.S. Agriculture Department announced yesterday. The definitive testing, done in England over the past two weeks, showed that the ailing animal, first flagged as suspicious in November, was infected with mad cow disease. The animal was retested after the USDA's inspector general requested the additional check because of continuing concerns about the sample dismissed by the agency. USDA Secretary Mike Johanns said that officials are just now trying to learn more about the origins of the animal, but that there is no indication that it was imported, as was the only other animal to test positive for the disease in the United States. That would make the newly identified animal the first born in this country found to have mad cow disease. Johanns sought yesterday to assure consumers that U.S. beef is safe, and that any suspect beef would have been kept off supermarket shelves. © 2005 The Washington Post Company

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 7551 - Posted: 06.24.2010

Nicola Jones The ongoing threat of prion disease was hashed over by a UK government advisory committee this week. They heard evidence from recent studies of these deformed proteins, which cause mad cow disease and its human version, new-variant Creutzfeldt-Jakob disease (vCJD). The committee will use the information to help formulate advice for UK food agencies and blood banks on whether they should take further measures against prion infections. "We have become more rather than less anxious," says Marc Turner from the Scottish National Blood Transfusion Service, Edinburgh. Two people are thought to have died from vCJD after being infected by blood transfusions. There are no documented cases of anyone getting prion disease through surgery, but there remains a theoretical risk. However, several commercial products are in the pipeline to keep surgical steel free of prions and at least one is expected to be on the market by the end of 2005 (see 'Enzyme washing power cleans up rogue prions' ). British blood banks have already taken action to reduce prion content in blood products by, for example, removing white blood cells. They may also consider prion filtering, although this would be very expensive, and they could exclude donors of certain ages, although this would dramatically reduce blood supplies. "We are in a position of trading risks," says Turner. ©2005 Nature Publishing Group

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 6978 - Posted: 06.24.2010

Roxanne Khamsi One assumption lies at the root of efforts to keep the meat we eat safe from mad cow disease: that tissues beyond an animal's brain, spinal cord and immune system are free of the prions that cause the disease. A disturbing study now shows that assumption to be false. Researchers have found that if an animal falls ill with another infection, its immune response can carry large numbers of prions to organs throughout its body. "The rules no longer apply," warns pathologist Adriano Aguzzi at Zurich University Hospital, Switzerland, who led the research. Mad cow disease, more correctly known as bovine spongiform encephalopathy (BSE), is believed to be caused by rogue proteins called prions. When these prions enter the human food chain, they can cause the equivalent disease in humans, called new-variant Creutzfeldt-Jakob disease (vCJD). ©2005 Nature Publishing Group

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 6728 - Posted: 06.24.2010

Canada has found its third cow infected with BSE - bringing the number of native mad cows detected in North America to four. All of the infected cows detected so far were born in Alberta, Canada, where a clinical case of BSE was found in an imported British cow in 1993. This raises the question of whether the infection might have been limited to the province by chance, or whether other regions of the continent are just not looking hard enough to find infected cattle. In particular, the US surveillance programme has come under criticism. The most recently discovered infected cow was born in March 1998 - seven months after feeding beef remains to cattle was banned. The Canadian Food Inspection Agency (CFIA) says it was probably infected by feed made just before the ban. It was detected as part of Canada's surveillance programme which, like the one in the US, focuses on "high risk" cattle, those found dead or "downers" unable to stand. Experience in Europe has shown that these cattle are much more likely to have BSE than apparently healthy ones. The programme - which discovered the country's first case in May 2003 - found another Alberta-born mad cow in December 2004, this one born just before the 1997 feed ban. The sole case found so far in the US, in December 2003, was a downer born and probably infected in Alberta. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 6690 - Posted: 06.24.2010

By ROB GILLIES, THE ASSOCIATED PRESS TORONTO -- U.S. agriculture officials reaffirmed their support for lifting the ban on Canadian beef despite the discovery of a second case of mad cow disease in Canada, expressing confidence that public health measures will protect American livestock and consumers. Canada's Food Inspection Agency said yesterday that an older dairy cow from the province of Alberta has tested positive for bovine spongiform encephalopathy, or mad cow disease. The results confirmed preliminary tests released last week. Canada suspects the cow became infected through contaminated animal feed. The cow was born in 1996, before a 1997 ban on certain types of feed, the agency said. It did not enter the human food or animal feed supply and posed no risk to the public, the agency said. The disease attacks an animal's nervous system. Food contaminated with the prions that cause it can afflict people with usually fatal variant Creutzfeldt-Jakob disease. ©1996-2004 Seattle Post-Intelligencer

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 6648 - Posted: 06.24.2010

Helen Pearson The infectious proteins called prions that cause the human form of mad cow disease may hitch into the body on the back of another meat protein, US researchers have shown. The finding may help to explain how the rogue prions jump between species. Disease-causing prions are thought to have passed into people when they ate beef from infected cattle, triggering the brain wasting condition called new-variant Creutzfeldt-Jakob disease, or vCJD. But researchers have not been sure exactly how prions enter the body. To find out, Neena Singh and her team at Case Western Reserve University in Cleveland, Ohio, mimicked the process of eating and digesting infected meat. They mashed up brain tissue that contained prions from patients who had a form of Creutzfeldt-Jakob disease. They then exposed it to a range of harsh digestive enzymes from the mouth, stomach and intestine, which normally break proteins into pieces. Prions, which are known to be enormously tough, escape this attack almost unscathed, they showed, as does a second type of protein called ferritin, which stores iron and is abundant in meat. The two proteins seem to stick together, they report in the Journal of Neuroscience1. ©2004 Nature Publishing Group

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 6592 - Posted: 06.24.2010

Jim Giles People with genes thought to protect against variant Creutzfeldt-Jakob disease (vCJD) may still be at risk of developing some strains of the illness, animal studies suggest. All of the 146 British people who have died from vCJD, which is thought to be caused by eating meat infected with the prion protein that causes mad cow disease, have a genetic variation known as MM. This led some researchers to hope that people with different variants, who make up 60% of the population, may be protected from the disease. But mice with such supposedly protective genes still seem to be susceptible to infection with the rogue protein, report John Collinge and colleagues at University College London in a paper published online by Science1. Researchers are cautious about the study's implications for humans, but say that it adds weight to the possibility that tainted beef could have infected more people than was originally thought. "In future we might see different types of CJD," predicts Markus Glatzel, who studies the disease at the University of Zurich in Switzerland. "This is a very important study." ©2004 Nature Publishing Group

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 6406 - Posted: 06.24.2010

Eighteen years after BSE first emerged in the UK, we still have little idea how to treat people who have contracted the human version, variant Creutzfeldt-Jakob Disease (vCJD). An investigation by New Scientist has revealed that the relatives of people with vCJD are frustrated by the slow progress being made to find new treatments. Time and effort are being wasted researching drugs that simply do not work, they say, while other, radical, treatments are not being made readily available. But while researchers privately disagree over which approaches show most promise, they say there is now a united effort to find a drug best able to save lives. Later this month, the UK government's Medical Research Council will officially launch a trial of potential treatments, after four years of argument over which to test. Called the "PRION-1" trial it will focus on quinacrine, an anti-malarial drug that showed early promise in treating various forms of CJD. The National Prion Disease Clinic at St Mary's Hospital in London has already given the drug to around 20 patients, but the results are not yet in. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 5954 - Posted: 06.24.2010

Test-tube 'prions' could advance study of mad cow disease David Perlman, Chronicle Science Editor Scientists at UCSF have created synthetic prions -- tiny protein particles -- and shown they can cause brain disease in laboratory animals and replicate without any genetic material inside them. The achievement could lead to new tools for early detection of the faulty forms of prions that are known to cause mad cow disease in cattle and the rare, apparently spontaneous Creutzfeld-Jakob disease in humans, the researchers say. The work may also advance research into more common degenerative nervous system disorders such as Alzheimer's, Parkinson's and amyotrophic lateral sclerosis, known commonly as Lou Gehrig's disease, according to the UCSF scientists. The new research is being reported today in the journal Science by Dr. Giuseppe Legname, a neurologist in the laboratory of senior author Dr. Stanley Prusiner, who won the Nobel Prize for his discovery of prions nearly 25 years ago and has been working on their puzzles ever since. ©2004 San Francisco Chronicle

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 5914 - Posted: 06.24.2010

Helen Pilcher Researchers have created a synthetic protein that makes mice display symptoms similar to those of mad cow disease. The protein, called a prion, helps to resolve a long-standing debate on the cause of certain degenerative brain conditions, such as Creutzfeldt-Jakob disease (CJD) in humans and bovine spongiform encephalopathy (BSE) in cattle. Being able to manufacture the rogue protein in the lab may also aid the development of new therapies and speedy diagnostic tests. Sporadic CJD, which accounts for 85% of prion diseases in humans, is thought to develop spontaneously. Researchers believe that healthy brain prions somehow become twisted out of shape and go on to trigger the production of more misshapen proteins. As the brain degenerates, patients lose the power of speech and movement. As there is no effective treatment, the disease is invariably fatal. But there is controversy over whether a protein alone can trigger the disease. Many researchers believe that the infectious agent must also contain genetic material, such as DNA or RNA, in order to instruct the healthy proteins to turn bad. ©2004 Nature Publishing Group

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders
Link ID: 5910 - Posted: 06.24.2010