Posts Tagged "Brain"

Prion diseases are rare conditions similar to those caused by viruses that are caused by misfolded proteins known as prions. The most well-known of these is the neuro-degenerative Creutzfeldt-Jakob disease, which is commonly known for the way it appears in cows as Mad Cow disease. But according to a recent study, multiple system atrophy (MSA), another neurological disorder, can also be classified as a prion disease. The findings, published in the Proceedings of the National Academy of Sciences, suggest there are unseen ways in which MSA can be transmitted, and may even lead to possible treatment options.

First identified in 1960, MSA is an extremely rare condition that impairs the body’s involuntary functions. Its symptoms are similar to those that characterize Parkinson’s disease, including slowed movement and trouble with balance. These symptoms eventually lead to the patient’s death. While the cause of MSA was never fully understood, Kurt Giles, senior author of the recent study, said his team has now “conclusively shown that a new type of prion causes MSA.”

The findings mark the first time in 50 years that a human disease has been found to be caused by a new prion. For the study, the team exposed human MSA tissue to mice, which then went on to experience neurodegeneration. Exposure to brain tissue from these mice could then cause the disease to spread to other mice. The team observed that the culprit was a misfolded version of a protein called alpha-synuclein, which not only allowed the disease to spread from human tissue to mouse, but also to human cell cultures.

Prion diseases are a group of conditions that affect the nervous system in humans and animals. The most common symptoms of prion diseases in humans are impaired brain function and difficulty coordinating movements. These symptoms usually worsen over time and inevitably lead to the patient’s death.

Source: Medical Daily

Scientists have discovered a molecule that can interrupt an important stage in the development of Alzheimer’s disease. The molecule sticks to faulty proteins and stops them forming toxic clusters in the brain.

The UK and Swedish researchers suggest their finding will help the discovery of drugs that could halt Alzheimer’s disease progression.

They write about their discovery and its implications in the journal Nature Structural & Molecular Biology.

Lead author Dr. Samuel Cohen – a research fellow at St John’s College in Cambridge, UK – says with studies like theirs, we are beginning to reap the rewards of the extensive work that has been done to increase our understanding of the microscopic processes involved in the development of Alzheimer’s. He adds:

“Our study shows, for the first time, one of these critical processes being specifically inhibited, and reveals that by doing so we can prevent the toxic effects of protein aggregation that are associated with this terrible condition.”

Many functions in cells are carried out by carefully folded proteins. Folding is an energy-efficient way of ensuring distant parts of the protein molecule that need to interact are near each other. Some of these structures are complex and need the help of housekeeping molecules called “chaperones.”

A key step in the development of Alzheimer’s and other degenerative diseases is the accumulation or “nucleation” of misfolded proteins – known as amyloid fibrils – that do not disperse or dissolve away but form toxic clusters and help the disease spread in the brain.

The molecule that the international team has discovered is a chaperone called Brichos that sticks to threads of amyloid fibrils and stops them coming into contact with each other, thus breaking the toxic chain reaction.

Source: Medical News Today

Almost a century after the discovery that sleep helps us remember things, scientists are beginning to understand why.

During sleep, the brain produces chemicals that are important to memory and relives events we want to remember, scientists reported this week at the Society for Neuroscience meeting in Washington D.C.

“One of the most profound effects of a night of sleep is the improvement in our ability to remember things,” says Ravi Allada, a sleep researcher at Northwestern University. Yet this connection hasn’t been well-understood, he says.

That’s changing, thanks to recent research from scientists including Jennifer Choi Tudor from the University of Pennsylvania. At the meeting, Tudor presented a study involving a brain chemical (known as 4EBP2) that is produced during sleep and is thought to play a role in remembering new information.

Previous experiments have shown that sleep-deprived mice have memory problems and lower levels of this chemical. So the team tried injecting the chemical into the brains of mice, then deprived them of sleep. “With the injection, their memory is normal,” Tudor says.

Sleep is also a time when old memories can be modified and new memories can be formed, says Karim Benchenane from the National Center for Scientific Research in Paris. Benchenane was part of a team that studied the brains of rats while the rats were awake, as well as during sleep.

When the animals were awake and traveling around their cages, the scientists identified brain cells that became active only when the rats were in a specific location. During sleep, these same cells became active in the same order, indicating that the rats were reliving their travels and presumably strengthening their memories of places they’d been.

Source: NPR

Ever feel like a zombie after just one sleepless night? Your brains certainly do: According to a new study in the journal Sleep, a single night of sleep deprivation results in an uptick of two enzymes usually associated with brain damage.

Researchers from Uppsala Universityin Sweden put 15 young, well-rested and healthy men through a night of total sleep deprivation. When they tested their blood the next morning, they found higher concentrations of the enzyme NSE and S-100B — both biomarkers of cell damage in the brain that could lead to cognitive problems and memory loss.

These findings follow research earlier this year showing that sleep “cleans” your brain of toxins and other substances than can destroy your neurons. “With this finding in mind, once could speculate that the sleep loss-induced rise in circulating levels of NSE and S-100B in our study may be a result of increased neuronal damage,” says study author Christian Benedict, PhD, associate professor of neuroscience at the university. NSE is an enzyme found in all neurons, and S-100B is the “glue of the brain”, Dr. Benedict says. Some research suggests that S100B is important for information processing, and elevated levels make it easy for doctors to detect brain cell damage through a simple blood test.

The researchers havent yet conducted the experiment on women. But findings could apply, since the levels of NSE and S-100B were significantly higher compared to participants’ natural baselines. Still, the levels weren’t higher than those found after a concussion. “A single night of sleep loss is not equally harmful as head injury,” says Dr. Benedict. “However, it does suggest that getting a regular, good night’s sleep may be useful for supporting brain health.”

Read more about the study here.

A study conducted by scientists at the University of Rochester Medical Center shows that, during sleep, the brain flushes out cellular waste. Though the study was conducted on mouse brains, the lead researcher said that the plumbing system also exists in dogs and baboons, and it’s logical to think that the human brain also clears away toxic substances. This study may provide new clues to treat Alzheimer’s disease and other disorders, in which toxic substances build up.

When we sleep, our brains get rid of gunk that builds up while we’re awake. The finding may mean that for people with dementia and other mind disorders, “sleep would perhaps be even more important in slowing the progression of further damage,” Dr. Clete Kushida, medical director of the Stanford Sleep Medicine Center, said in an email. Kushida did not participate in the study, which appeared in the journal Science.

People who don’t get enough shut-eye have trouble learning and making decisions, and are slower to react. But despite decades of research, scientists can’t agree on the basic purpose of sleep. Reasons range from processing memory, saving energy to regulating the body.

The latest work, led by scientists at the University of Rochester Medical Center, adds fresh evidence to a long-standing view: When we close our eyes, our brains go on a cleaning spree. The team previously found a plumbing network in mouse brains that flushes out cellular waste. For the new study, the scientists injected the brains of mice with beta-amyloid, a substance that builds up in Alzheimer’s disease, and followed its movement. They determined that it was removed faster from the brains of sleeping mice than awake mice.

The team also noticed that brain cells tend to shrink during sleep, which widens the space between the cells. This allows waste to pass through that space more easily.Though the work involved mouse brains, lead researcher Dr. Maiken Nedergaard said this plumbing system also exists in dogs and baboons, and it’s logical to think that the human brain also clears away toxic substances. Nedergaard said the next step is to look for the process in human brains.

In an accompanying editorial, neuroscientist Suzana Herculano-Houzel of the Federal University of Rio de Janeiro said scientists have recently taken a heightened interest in the spaces between brain cells, where junk is flushed out.

It’s becoming clearer that “sleep is likely to be a brain state in which several important housekeeping functions take place,” she said in an email.

The study was funded by the National Institute of Neurological Disorders and Stroke. In a statement, program director Jim Koenig said the finding could lead to new approaches for treating a range of brain diseases.

Source: USA Today