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Kelly Crowe · CBC News · Last fall, a dangerous animal sickness — chronic wasting disease (CWD) — was detected in a Quebec deer farm. It was a disturbing development — the first sign of this highly contagious infection outside of Alberta and Saskatchewan. There were almost 3,000 deer in the herd. Eleven tested positive for CWD. The rest — more than 2,700 animals — tested negative and were released into the food chain. It was a controversial decision, in part, because so little is known about the human health risk from CWD. The Canadian Food Inspection Agency's website cautions that: "A negative test result does not guarantee that an individual animal is not infected with CWD." "There is not currently a food safety test available for any prion disease," CFIA's spokesperson told CBC News in an email. "The tests that are used are the best available. In accordance with Health Canada's precautionary approach, no animals known to be infected were released into the human food chain." CWD is similar to another frightening animal illness — mad cow disease, officially called "bovine spongiform encephalopathy" or BSE. It is a fatal infection in cattle that can be spread to humans through beef consumption. Both CWD and BSE are caused by a strange protein — a prion — which can jump the species barrier, triggering a deadly cascade of neurological damage. Worldwide, BSE has caused about 225 cases of human prion disease called "variant Creutzfeldt Jacob Disease (vCJD)." There is no treatment and no cure. After an epidemic of mad cow disease in the U.K. more than two decades ago, governments developed strict controls to prevent BSE-infected cattle from being processed for human food. But so far there are few official controls in place to keep CWD out of the food chain.

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 26349 - Posted: 06.24.2019

National Institutes of Health scientists have used human skin cells to create what they believe is the first cerebral organoid system, or “mini-brain,” for studying sporadic Creutzfeldt-Jakob disease (CJD). CJD is a fatal neurodegenerative brain disease of humans believed to be caused by infectious prion protein. It affects about 1 in 1 million people. The researchers, from NIH’s National Institute of Allergy and Infectious Diseases (NIAID), hope the human organoid model will enable them to evaluate potential therapeutics for CJD and provide greater detail about human prion disease subtypes than the rodent and nonhuman primate models currently in use. Human cerebral organoids are small balls of human brain cells ranging in size from a poppy seed to a small pea. Their organization, structure, and electrical signaling are similar to brain tissue. Because these cerebral organoids can survive in a controlled environment for months, nervous system diseases can be studied over time. Cerebral organoids have been used as models to study Zika virus infection, Alzheimer’s disease, and Down syndrome. In a new study published in Acta Neuropathologica Communications, scientists at NIAID’s Rocky Mountain Laboratories discovered how to infect five-month-old cerebral organoids with prions using samples from two patients who died of two different CJD subtypes, MV1 and MV2. Infection took about one month to confirm, and the scientists monitored the organoids for changes in health indicators, such as metabolism, for more than six months. By the end of the study, the scientists observed that seeding activity, an indication of infectious prion propagation, was present in all organoids exposed to the CJD samples. However, seeding was greater in organoids infected with the MV2 sample than the MV1 sample. They also reported that the MV1-infected organoids showed more damage than the MV2-infected organoids.

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 13: Memory, Learning, and Development
Link ID: 26331 - Posted: 06.15.2019

National Institutes of Health scientists and their colleagues have found evidence of the infectious agent of sporadic Creutzfeldt-Jakob disease (CJD) in the eyes of deceased CJD patients. The finding suggests that the eye may be a source for early CJD diagnosis and raises questions about the safety of routine eye exams and corneal transplants. Sporadic CJD, a fatal neurodegenerative prion disease of humans, is untreatable and difficult to diagnose. Prion diseases originate when normally harmless prion protein molecules become abnormal and gather in clusters and filaments in the body and brain. Scientists hope that early diagnosis of prion and related diseases—such as Alzheimer’s, Parkinson’s and dementia with Lewy bodies—could lead to effective treatments that slow or prevent these diseases. Scientists from NIH’s National Institute of Allergy and Infectious Diseases (NIAID) collaborated on the research with colleagues from the University of California at San Diego and UC-San Francisco. About 40 percent of sporadic CJD patients develop eye problems that could lead to an eye exam, meaning the potential exists for the contamination of eye exam equipment designed for repeat use. Further, cadaveric corneal transplants from undiagnosed CJD patients have led to two probable and three possible cases of disease transmission, the researchers say. Previous studies have shown that the eyes of CJD patients contain infectious prions, though the distribution of prions among the various components of the eye was not known. To address this question, the scientists recruited 11 CJD patients who agreed to donate their eyes upon death. The researchers found evidence of prion infection throughout the eyes of all 11 deceased patients using real time quaking-induced conversion (RT-QuIC), a highly sensitive test NIAID scientists developed that detects prion seeding activity in a sample as evidence of infection.

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 7: Vision: From Eye to Brain
Link ID: 25706 - Posted: 11.21.2018

By Alex Therrien Health reporter, BBC News Doctors have been given permission to give a British man with CJD a pioneering treatment, in a world first. There is currently no treatment for the rare but lethal brain disease, known as the human version of "mad cow disease". Doctors in London were given permission for the trial use on a human for the first time by the Court of Protection. Scientists say lab testing of the man-made antibody has been encouraging, but they admit they do not know how their patient will respond. The patient in this case, who has not been named, has sporadic CJD, the most common form of the disease in humans. This is different from variant CJD, the version linked to eating beef infected by bovine spongiform encephalopathy, or BSE. Sporadic CJD happens when healthy proteins in the human body - prions - become spontaneously misshapen and build up in the brain. The man-made antibody treatment, called PRN100, aims to prevent abnormal prions from being able to attach themselves to healthy proteins, meaning that they cannot grow and cause devastation throughout the brain. University College London Hospitals NHS Foundation Trust (UCLH) is set to use it in a patient for the first time after a judge from the Court of Protection confirmed on Monday that it was lawful and in the patient's best interests to receive it. © 2018 BBC

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 25554 - Posted: 10.10.2018

Prion diseases are slow degenerative brain diseases that occur in people and various other mammals. No vaccines or treatments are available, and these diseases are almost always fatal. Scientists have found little evidence of a protective immune response to prion infections. Further, microglia — brain cells usually involved in the first level of host defense against infections of the brain — have been thought to worsen these diseases by secreting toxic molecules that can damage nerve cells. Now, scientists have used an experimental drug, PLX5622, to test the role of microglia against scrapie, a prion disease of sheep. PLX5622 rapidly kills most of the microglia in the brain. When researchers gave the drug to mice infected with scrapie, microglia were eliminated and the mice died one month faster than did untreated mice. The results, published in the Journal of Virology by researchers from the National Institute of Allergy and Infectious Diseases at the National Institutes of Health, suggest that microglia can defend against a prion infection and thus slow the course of disease. The scientists hypothesize that microglia trap and destroy the aggregated prion proteins that cause brain damage. The findings suggest that drugs that increase the helpful activity of microglia may have a role in slowing the progression of prion diseases. Researchers are now studying the details of how microglia may be able to destroy prions in the brain. The scientists note that microglia could have a similar beneficial effect on other neurodegenerative diseases associated with protein aggregation, such as Alzheimer’s disease and Parkinson’s disease.

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 24991 - Posted: 05.18.2018

/ By Madeline Bodin This winter was a little quieter than usual for the folks at Silver Creek Specialty Meats in Oshkosh, Wisconsin. For generations, winter was when hunters would make regular visits to the low-rise white brick facility near the shore of Lake Winnebago, carrying the odds and ends of the deer they had killed the previous fall so it could be turned into venison sausages. This year, though, no hunters came. “It’s not quite black and white. What do we do in the meantime?” In August, Silver Creek Specialty Meats sent out a letter notifying customers that it would no longer accept venison for processing. “As you are probably aware,” the letter said, “chronic wasting disease in the wild deer population of the State of Wisconsin has been steadily spreading. The disease has now been found in wild deer in 19 counties throughout the state. Due to the spread of the disease it has become extremely difficult to screen out any venison coming from CWD infected areas.” Deer with chronic wasting disease, or CWD, tremble and drool. They often cannot hold their heads up. Eventually, they lose so much weight that they are little more than hide and bone. The disease arises from a particular prion — single-protein infectious agents linked to various neurodegenerative diseases in mammals. And prion diseases are always fatal. Copyright 2018 Undark

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 24880 - Posted: 04.19.2018

By DENISE GRADY Scientists have found prions — abnormal proteins widely believed to cause a rare, brain-destroying disease — in the skin of 23 patients who had died from it, according to a study published on Wednesday. The discovery suggests that skin samples might be used to improve detection of the disorder, Creutzfeldt-Jakob disease, which now is usually diagnosed with much more difficult procedures, like brain biopsies or autopsies. But the presence of prions in the skin also raises unsettling questions about whether medical instruments could become contaminated even during surgery that does not involve the brain and then spread the disease to other patients. The prions stick to stainless steel and are notoriously hard to destroy. Creutzfeldt-Jakob disease affects one person in a million worldwide, with about 300 cases a year in the United States, according to the National Institutes of Health. People are typically about age 60 when it starts. It is cruel and rapidly fatal: Most patients die within a year of becoming ill. They deteriorate mentally, weaken, move uncontrollably, and may become blind and unable to speak. The disease belongs to the same class of brain disorders as mad-cow disease. The findings do not mean that Creutzfeldt-Jakob disease can be transmitted by touch or casual contact, said the senior author of the study, Dr. Wen-Quan Zou, at Case Western University School of Medicine. Patients are not dangerous, he emphasized. The researchers also said that although the disease had been transmitted decades ago by corneal transplants and certain neurosurgical procedures, there was no definitive evidence that other types of surgery had ever spread it. And the levels found in skin are far lower than those in the brain. Despite the new findings, there is no reason to change the medical care given to patients with the disease or to people known to have genetic mutations that may predispose them to Creutzfeldt-Jakob or related illnesses, the researchers said. © 2017 The New York Times Company

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 24356 - Posted: 11.24.2017

Carl Zimmer Mark D. Zabel wants to set some fires. Dr. Zabel and his colleagues are developing plans to burn plots of National Park Service land in Arkansas and Colorado. If the experiments turn out as the researchers hope, they will spare some elk and deer a gruesome death. Across a growing swath of North America, these animals are dying from a mysterious disorder called chronic wasting disease. It’s caused not by a virus or bacterium, but a deformed protein called a prion. When ingested, prions force normal proteins in the animal’s body to become deformed as well. Over the course of months, prions can gradually wreck the animal’s nervous system, ultimately killing it. This year is the 50th anniversary of the discovery of chronic wasting disease. In the September issue of Microbiology and Molecular Biology Reviews, Dr. Zabel, an immunologist at Colorado State University, and his former graduate student Aimee Ortega survey what scientists have learned about the slow-spreading plague. It makes for ominous reading. “There’s a lot that we still don’t know and don’t understand about the disease,” Dr. Zabel said in an interview. Once chronic wasting disease gets a foothold, it can spread relentlessly. It’s now documented in 24 states, and continues to expand into new ranges. In some herds, as many as half of the animals carry prions. It’s only been in recent years that scientists have gained crucial clues to how the disease spreads. Direct contact, it turns out, isn’t the only way that the prions get from one animal to another. © 2017 The New York Times Company

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 23781 - Posted: 06.27.2017

By Erik Stokstad A year after a deadly and highly contagious wildlife disease surfaced in Norway, the country is taking action. Chronic wasting disease (CWD), caused by misfolded proteins called prions, has already ravaged deer and elk in North America, costing rural economies millions in lost revenue from hunting. Its presence in Norway’s reindeer and moose—the first cases in Europe—is “a very serious situation for the environment and for our culture and traditions,” says Bjørnar Ytrehus, a veterinary researcher at the Norwegian Institute for Nature Research in Trondheim. Last week, Norway’s minister of agriculture and food gave the green light for hunters to kill off the entire herd in which three infected individuals were found, about 2000 reindeer, or nearly 6% of the country’s wild population. “We have to take action now,” says Karen Johanne Baalsrud, director of plant and animal health at the Norwegian Food Safety Authority in Oslo. The deer’s habitat will be quarantined for at least 5 years to prevent reinfection. The odds of a successful eradication, experts say, will depend largely on how long CWD has been present in Norway. CWD, discovered in 1967, has been found in 24 U.S. states and two Canadian provinces, and it has been spread in part by shipments of infected animals. Many species of cervids are susceptible, including elk, moose, and several kinds of deer. Infected animals typically begin showing symptoms such as weight loss, lethargy, and drooling 2 to 3 years after infection and then die within months. In Wyoming, where CWD has been endemic for decades, up to 40% of some herds are infected, and white-tailed deer populations are declining by 10% a year. © 2017 American Association for the Advancement of Science

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 23443 - Posted: 04.04.2017

Rae Ellen Bichell By the time Kay Schwister got her diagnosis last summer, she couldn't talk anymore. But she could still scowl, and scowl she did. After weeks of decline and no clue what was causing it, doctors had told Schwister — a 53-year-old vocational rehab counselor and mother of two from Chicago — that she had an incurable disease called Creutzfeldt-Jakob disease, or CJD. The disease was shrinking Kay's brain, and riddling it with holes. She would likely only live a few more weeks, the doctors said. It was a diagnosis that no one could ever want. But the fact that Schwister was able to get a firm diagnosis while still alive is a relatively new development that represents a step forward in understanding a group of devastating neurological disorders. And, some biochemists say, it could lead to better ways of diagnosing brain diseases that are much more common, including Parkinson's and Alzheimer's. For Kay Schwister it all started in the spring of 2016, when she started getting headaches and feeling dizzy all the time. Aging, she told herself, just didn't feel very good. Over the next few weeks, she got steadily worse. "She got to the point where she was so nauseous and so dizzy that she stopped driving and actually stopped working," says her husband, Tim Schwister. By the time Kay entered the emergency room last June her speech had changed. She was enunciating things in a strange way, and finishing each sentence on a really high note. Doctors drew blood and spinal fluid and tested it for things like multiple sclerosis and mercury poisoning. Those tests came back negative. Soon, Kay couldn't talk or walk. © 2017 npr

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 23191 - Posted: 02.06.2017

Charles Q. Choi Prions, the infectious agents best known for causing degenerative brain disorders such as ‘mad cow’ disease, may have been spotted in bacteria. A section of a protein in Clostridium botulinum, the microbe that causes botulism, can behave like a prion when it is inserted into yeast and Escherichia coli bacteria, researchers report in the 13 January issue of Science1. Prions are formed by proteins that can fold in a number of structurally distinct ways. A prion version of a protein can perpetuate itself in an infectious manner by converting normal forms of that protein into the prion version. Scientists first discovered prions in the 1980s as the agents behind fatal brain disorders known as transmissible spongiform encephalopathies. Since then, researchers have found the misfolded proteins in mammals, insects, worms, plants and fungi2, and learned that not all prions harm their hosts. But until now, prions were only seen in the cells of eukaryotic organisms, a group that includes animals, plants and fungi. In the latest study, researchers analysed roughly 60,000 bacterial genomes using software trained to recognize prion-forming proteins in yeast. They focused on a section of the bacterial protein Rho. In many bacteria, such as C. botulinum and E. coli, Rho is a global regulator of gene expression, meaning that it can control the activity of many genes. © 2017 Macmillan Publishers Limited,

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 23104 - Posted: 01.14.2017

By Kelly Servick The “mad cow disease” epidemic that killed more than 200 people in Europe peaked more than a decade ago, but the threat it poses is still real. Eating meat contaminated with bovine spongiform encephalopathy and its hallmark misshapen proteins, called prions, can cause a fatal and untreatable brain disorder, variant Creutzfeldt-Jakob disease (vCJD). Thousands of Europeans are thought to be asymptomatic carriers, and they can spread prions through blood donations. So for years, researchers have sought a test to safeguard blood supplies. This week, two teams bring that goal closer. They describe methods for detecting prions in blood that proved highly accurate in small numbers of samples from infected people and controls. “There is new technology to go forward, and it looks promising,” says Jonathan Wadsworth, a biochemist who studies prion disease at University College London. “These are definitely very welcome papers.” Analyses of discarded appendix and tonsil samples suggest that as many as one in 2000 people in the United Kingdom carries abnormal prions—misfolded variations of a naturally abundant protein, which prompt surrounding healthy proteins to fold and clump abnormally. No one knows how many of these carriers will ever develop vCJD; incubation periods as long as 50 years have been reported. Once symptoms occur—first depression and hallucinations, and eventually dementia and loss of motor control—patients survive about a year. Four people are known to have contracted vCJD through a blood transfusion from an infected donor. © 2016 American Association for the Advancement of Science.

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 23007 - Posted: 12.22.2016

Urine could potentially be used for a quick and simple way to test for CJD or "human mad cow disease", say scientists in the journal JAMA Neurology. The Medical Research Council team say their prototype test still needs honing before it could be used routinely. Currently there is no easy test available for this rare but fatal brain condition. Instead, doctors have to take a sample of spinal fluid or brain tissue, or wait for a post-mortem after death. What they look for is tell-tale deposits of abnormal proteins called prions, which cause the brain damage. Building on earlier US work, Dr Graham Jackson and colleagues, from University College London, have now found it is also possible to detect prions in urine. This might offer a way to diagnose CJD rapidly and earlier, they say, although there is no cure. Creutzfeldt-Jakob disease (CJD): CJD is a rare, but fatal degenerative brain disorder caused by abnormal proteins called prions that damage brain cells. There are several forms of the disease: sporadic, which occurs naturally in the human population, and accounts for 85% of all CJD cases variant CJD, linked to eating beef infected by bovine spongiform encephalopathy (BSE) iatrogenic infection, caused by contamination during medical or surgical treatment In the 1990s it became clear that a brain disease could be passed from cows to humans. The British government introduced a ban on beef on the bone. Since then, officials have kept a close check on how many people have become sick or died from CJD. © 2016 BBC

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 22724 - Posted: 10.05.2016

By Abby Olena Mammalian prions are notoriously difficult as structural biology subjects, given their insolubility and tendency to aggregate. Researchers have now overcome these challenges to figure out the preliminary structure of a shortened form of infectious prion (PrPSc), which they report today (September 8) in PLOS Pathogens. “For the first time, we have a structure of an infectious mammalian prion,” said Giuseppe Legname of Scuola Internazionale Superiore di Studi Avanzati in Trieste, Italy, who was not involved in this study. “It’s a very important paper,” he added. “What we have done is to obtain a very simple, very preliminary idea of what the structure of these mammalian prions are,” said study coauthor Jesús Requena of the University of Santiago de Compostela in Spain. Requena and colleagues generated a shortened form of PrPSc by injecting a laboratory strain of prions into transgenic mice that express a truncated form of normal cellular prion protein (PrPC), which lacks the attachment of a membrane anchor present in full-length PrPSc. In nature, PrPC transforms into full-length PrPSc, which causes Creutzfeldt-Jakob disease in humans, scrapie in sheep, and mad cow disease. The absence of the membrane anchor in shortened PrPSc from the transgenic mice allowed the researchers to isolate a fairly homogeneous population of PrPSc. They confirmed that this population was infectious by inoculating wild-type mice, which then developed symptoms of prion disease. © 1986-2016 The Scientist

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 22638 - Posted: 09.10.2016

Anna Nowogrodzki Prions, the misfolded proteins that are known for causing degenerative illnesses in animals and humans, may have been spotted for the first time in plants. Researchers led by Susan Lindquist, a biologist at the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, report that they have found a section of protein in thale cress (Arabidopsis) that behaves like a prion when it is inserted into yeast. In plants, the protein is called Luminidependens (LD), and it is normally involved in responding to daylight and controlling flowering time. When a part of the LD gene is inserted into yeast, it produces a protein that does not fold up normally, and which spreads this misfolded state to proteins around it in a domino effect that causes aggregates or clumps. Later generations of yeast cells inherit the effect: their versions of the protein also misfold. This does not mean that plants definitely have prion-like proteins, adds Lindquist — but she thinks that it is likely. “I’d be surprised if they weren’t there,” she says. To prove it, researchers would need to grind up a plant and see whether they could find a protein such as LD in several different folded states, as well as show that any potential prion caused a misfolding cascade when added to a test-tube of protein. Lindquist adds that because she's not a plant scientist — her focus is on using yeast to investigate prions — she hasn't tried these experiments. The study is reported on 25 April in the Proceedings of the National Academy of Sciences1. © 2016 Nature Publishing Group

Related chapters from BN8e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders; Chapter 10: Biological Rhythms and Sleep
Link ID: 22147 - Posted: 04.26.2016

Rachel Becker A highly contagious and deadly animal brain disorder has been detected in Europe for the first time. Scientists are now warning that the single case found in a wild reindeer might represent an unrecognized, widespread infection. Chronic wasting disease (CWD) was thought to be restricted to deer, elk (Cervus canadensis) and moose (Alces alces) in North America and South Korea, but on 4 April researchers announced that the disease had been discovered in a free-ranging reindeer (Rangifer tarandus tarandus) in Norway. This is both the first time that CWD has been found in Europe and the first time that it has been found in this species in the wild anywhere in the world. “It’s worrying — of course, especially for animals. It’s a nasty disease,” says Sylvie Benestad, an animal-disease researcher at the Norwegian Veterinary Institute in Oslo who, along with colleague Turid Vikøren, diagnosed the diseased reindeer. A key question now is whether this is a rare — even unique — case, or if the disease is widespread but so far undetected in Europe. “If it’s similar to our prion disease in the United States and Canada, the disease is subtle and it would be easy to miss,” says Christina Sigurdson, a pathologist at the University of California, San Diego, who has shown that reindeer can contract CWD in a laboratory environment1. © 2016 Nature Publishing Group,

Related chapters from BN8e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 22117 - Posted: 04.19.2016

Tina Hesman Saey Sonia Vallabh knows what will probably kill her. In 2011, the Boston-area law school graduate learned she carries the same genetic mutation that caused her mother’s death from a rare brain-wasting prion disease. Prions are twisted forms of normal brain proteins that clump together and destroy nerves. About 10 to 15 percent of prion diseases are caused by a mutation in the PRNP gene, leading to such deadly diseases as Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syndrome and fatal familial insomnia, the disease that killed Vallabh’s mother. Grief, shared with family and friends, came first. Eventually, Vallabh realized, “We can’t get around this prognosis.… We’ve got to go through it.” So began her and husband Eric Minikel’s odyssey to learn about the disease that had turned their lives upside down. A scientist friend came by with a flash drive loaded with research papers about prion diseases. “We didn’t have the vocabulary” to understand the information, Vallabh says. So she took a sabbatical from her job to take biology and chemistry classes. Minikel kept writing transportation software, but attended night classes with his wife. Vallabh’s first foray into brain research was as a technician in a lab studying Huntington’s disease. During “science nights” at the couple’s home, scientist pals team-taught biology and biochemistry. The couple took the biggest step when Minikel left his consulting job and both enrolled in graduate school to study prion diseases. Prion proteins, some of which clump together or form fibrils, as in this E. coli bacteria, are often used to model how proteins misfold in some neurodegenerative disorders. © Society for Science & the Public 2000 - 2016

Related chapters from BN8e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 21922 - Posted: 02.22.2016

By Diana Kwon | In the human form of mad cow disease, called Creutzfeldt-Jakob, a person's brain deteriorates—literally developing holes that cause rapidly progressing dementia. The condition is fatal within one year in 90 percent of cases. The culprits behind the disease are prions—misfolded proteins that can induce normal proteins around them to also misfold and accumulate. Scientists have known that these self-propagating, pathological proteins cause some rare brain disorders, such as kuru in Papua New Guinea. But growing evidence suggests that prions are at play in many, if not all, neurodegenerative disorders, including Alzheimer's, Huntington's and Parkinson's, also marked by aggregations of malformed proteins. Until recently, there was no evidence that the abnormal proteins found in people who suffer from these well-known diseases could be transmitted directly from person to person. The tenor of that discussion suddenly changed this September when newly published research in the journal Nature provided the first hint such human-to-human transmission may be possible. (Scientific American is part of Springer Nature.) For the study, John Collinge, a neurologist at University College London, and his colleagues conducted autopsies on eight patients who died between the ages of 36 and 51 from Creutzfeldt-Jakob. All the subjects had acquired the disease after treatment with growth hormone later found to be contaminated with prions. The surprise came when the researchers discovered that six of the brains also bore telltale signs of Alzheimer's—in the form of clumps of beta-amyloid proteins, diagnostic for the disease—even though the patients should have been too young to exhibit such symptoms. © 2015 Scientific American,

Related chapters from BN8e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders; Chapter 5: The Sensorimotor System
Link ID: 21580 - Posted: 10.29.2015

By Simon Makin Scientists claim to have discovered the first new human prion in almost 50 years. Prions are misfolded proteins that make copies of themselves by inducing others to misfold. By so doing, they multiply and cause disease. The resulting illness in this case is multiple system atrophy (MSA), a neurodegenerative disease similar to Parkinson's. The study, published August 31 in Proceedings of the National Academy of Sciences, adds weight to the idea that many neurodegenerative diseases are caused by prions. In the 1960s researchers led by Carleton Gajdusek at the National Institutes of Health transmitted kuru, a rare neurodegenerative disease found in Papua New Guinea, and Creutzfeldt–Jakob disease (CJD), a rare human dementia, to chimpanzees by injecting samples from victims' brains directly into those of chimps. It wasn't until 1982, however, that Stanley Prusiner coined the term prion (for “proteinaceous infectious particle”) to describe the self-propagating protein responsible. Prusiner and colleagues at the University of California, San Francisco, showed this process caused a whole class of diseases, called spongiform encephalopathies (for the spongelike appearance of affected brains), including the bovine form known as “mad cow” disease. The same protein, PrP, is also responsible for kuru, which was spread by cannibalism; variant-CJD, which over 200 people developed after eating beef infected with the bovine variety; and others. The idea that a protein could transmit disease was radical at the time but the work eventually earned Prusiner the 1997 Nobel Prize in Physiology or Medicine. He has long argued prions may underlie other neurodegenerative diseases but the idea has been slow to gain acceptance. © 2015 Scientific American

Related chapters from BN8e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders; Chapter 5: The Sensorimotor System
Link ID: 21373 - Posted: 09.02.2015

Boer Deng A genetic variant protected some practitioners of cannibalism from prion disease. Scientists who study a rare brain disease that once devastated entire communities in Papua New Guinea have described a genetic variant that appears to stop misfolded proteins known as prions from propagating in the brain1. Kuru was first observed in the mid-twentieth century among the Fore people of Papua New Guinea. At its peak in the late 1950s, the disease killed up to 2% of the group's population each year. Scientists later traced the illness to ritual cannibalism2, in which tribe members ate the brains and nervous systems of their dead. The outbreak probably began when a Fore person consumed body parts from someone who had sporadic Creutzfeldt-Jakob disease (CJD), a prion disease that spontaneously strikes about one person in a million each year. Scientists have noted previously that some people seem less susceptible to prion diseases if they have an amino-acid substitution in a particular region of the prion protein — codon 1293. And in 2009, a team led by John Collinge — a prion researcher at University College London who is also the lead author of the most recent analysis — found another protective mutation among the Fore, in codon 1274. The group's latest work, reported on 10 June in Nature1, shows that the amino-acid change that occurs at this codon, replacing a glycine with a valine, has a different and more powerful effect than the substitution at codon 129. The codon 129 variant confers some protection against prion disease only when it is present on one of the two copies of the gene that encodes the protein. But transgenic mice with the codon-127 mutation were completely resistant to kuru and CJD regardless of whether they bore one or two copies of it. The researchers say that the mutation in codon 127 appears to confer protection by preventing prion proteins from becoming misshapen. © 2015 Nature Publishing Group,

Related chapters from BN8e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 21043 - Posted: 06.13.2015