(Press-News.org) Alzheimer's disease is thought to be caused by the buildup of abnormal, thread-like protein deposits in the brain, but little is known about the molecular structures of these so-called beta-amyloid fibrils. A study published by Cell Press September 12th in the journal Cell has revealed that distinct molecular structures of beta-amyloid fibrils may predominate in the brains of Alzheimer's patients with different clinical histories and degrees of brain damage. The findings pave the way for new patient-specific strategies to improve diagnosis and treatment of this common and debilitating disease.
"This work represents the first detailed characterization of the molecular structures of beta-amyloid fibrils that develop in the brains of patients with Alzheimer's disease," says senior study author Robert Tycko of the National Institutes of Health. "This detailed structural model may be used to guide the development of chemical compounds that bind to these fibrils with high specificity for purposes of diagnostic imaging, as well as compounds that inhibit fibril formation for purposes of prevention or therapy."
Tycko and his team had previously noticed that beta-amyloid fibrils grown in a dish have different molecular structures, depending on the specific growth conditions. Based on this observation, they suspected that fibrils found in the brains of patients with Alzheimer's disease are also variable and that these structural variations might relate to each patient's clinical history. But it has not been possible to directly study the structures of fibrils found in patients because of their low abundance in the brain.
To overcome this hurdle, Tycko and his collaborators developed a new experimental protocol. They extracted beta-amyloid fibril fragments from the brain tissue of two patients with different clinical histories and degrees of brain damage and then used these fragments to grow a large quantity of fibrils in a dish. They found that a single fibril structure prevailed in the brain tissue of each patient, but the molecular structures were different between the two patients.
"This may mean that fibrils in a given patient appear first at a single site in the brain, then spread to other locations while retaining the identical molecular structure," Tycko says. "Our study also shows that certain fibril structures may be more likely than others to cause Alzheimer's disease, highlighting the importance of developing imaging agents that target specific fibril structures to improve the reliability and specificity of diagnosis."
###
Cell, Lu et al.: "Molecular structure of beta -amyloid fibrils in Alzheimer's disease brain tissue."
Alzheimer's patients show striking individual differences in molecular basis of disease
2013-09-12
ELSE PRESS RELEASES FROM THIS DATE:
Darwin's dilemma resolved: Evolution's 'big bang' explained by 5x faster rates
2013-09-12
The incredible burst of innovation in animals' body plans and habits during the Cambrian explosion, between 540 and 520 million years ago, can be explained by a reasonable uptick in evolutionary rates. The discovery, based on the first rigorous estimates of early evolutionary rates in arthropods, shows that evolution's "big bang" is compatible with natural selection as Darwin envisioned it, say researchers reporting their findings in Current Biology, a Cell Press publication, on September 12.
"This simultaneous burst of life, with few or no precursors, had seemed at ...
Study sheds light on genetics of how and why fish swim in schools
2013-09-12
SEATTLE – How and why fish swim in schools has long fascinated biologists looking for clues to understand the complexities of social behavior. A new study by a team of researchers at Fred Hutchinson Cancer Research Center may help provide some insight.
To be published online in the Sept. 12 issue of Current Biology, the study found that two key components of schooling – the tendency to school and how well fish do it – map to different genomic regions in the threespine stickleback, a small fish native to the Northern Hemisphere.
That's important, said lead author Anna ...
Autism gene stunts neurons, but growth can be restored, in mice
2013-09-12
PROVIDENCE, R.I. [Brown University] — Brown University researchers have traced a genetic deficiency implicated in autism in humans to specific molecular and cellular consequences that cause clear deficits in mice in how well neurons can grow the intricate branches that allow them to connect to brain circuits. The researchers also show in their study (online Sep. 12, 2013, in Neuron) that they could restore proper neuronal growth by compensating for the errant molecular mechanisms they identified.
The study involves the gene that produces a protein called NHE6. Mutation ...
New info on an elusive green cicada
2013-09-12
For nearly 80 years, the North American cicada Okanagana viridis has received little attention in scientific literature, but a new article in the Annals of the Entomological Society of America provides the first notes on the song and ecology of this elusive species, and updates its known range.
O. viridis is unusual in a large genus of 60 otherwise arid- or cold-adapted, mostly western U.S. species, in that it is found in the temperate deciduous southern forests of Arkansas, Louisiana, Mississippi, Tennessee, and Texas. It is almost solid bright green, and it calls from ...
La Jolla Institute scientist identifies helper cells that trigger potent responses to HIV
2013-09-12
SAN DIEGO – (September 12, 2013) A major new finding that will significantly advance efforts to create the world's first antibody-based AIDS vaccine was published today by researchers from the La Jolla Institute for Allergy and Immunology.
La Jolla Institute scientist Shane Crotty, Ph.D., a respected vaccine researcher and member of one of the nation's top AIDS vaccine consortiums, showed that certain helper T cells are important for triggering a strong antibody response against HIV, the virus that causes AIDS. Helper T cells are disease-fighting immune cells key in ...
A microbe's trick for staying young
2013-09-12
Researchers have discovered a microbe that stays forever young by rejuvenating every time it reproduces. The findings, published in Current Biology, provide fundamental insights into the mechanisms of aging.
While aging remains an inevitable fact of life, an international team involving researchers from the University of Bristol and the Max-Planck Institute for Molecular Cell Biology and Genetics in Germany has found that this is not the case for a common species of yeast microbe which has evolved to stay young.
The team has shown that, unlike other species, the ...
Dali gets a health check: Using medical devices to diagnose art
2013-09-12
Scientists and conservators have developed a new method to diagnose painting canvases from the back, without disturbing a single fibre, to see if they can withstand the stress of handling and travel.
Using the method - which is similar to the way doctors measure blood sugar without the need for needles – scientists examined 12 paintings by the surrealist painter Salvador Dalí.
They assessed the 'health' of the canvases, which are known to degrade with time due to acidity and environmental conditions. Once a canvas is brittle, expensive conservation is required.
While ...
Biologists measure evolution's Big Bang
2013-09-12
A new study led by Adelaide researchers has estimated, for the first time, the rates of evolution during the "Cambrian explosion" when most modern animal groups appeared between 540 and 520 million years ago.
The findings, published online today in the journal Current Biology, resolve "Darwin's dilemma": the sudden appearance of a plethora of modern animal groups in the fossil record during the early Cambrian period.
"The abrupt appearance of dozens of animal groups during this time is arguably the most important evolutionary event after the origin of life," says lead ...
The peanut at the heart of our galaxy
2013-09-12
One of the most important and massive parts of the galaxy is the galactic bulge. This huge central cloud of about 10 000 million stars spans thousands of light-years, but its structure and origin were not well understood.
Unfortunately, from our vantage point from within the galactic disc, the view of this central region — at about 27 000 light-years' distance — is heavily obscured by dense clouds of gas and dust. Astronomers can only obtain a good view of the bulge by observing longer wavelength light, such as infrared radiation, which can penetrate the dust clouds.
Earlier ...
Probing methane's secrets: From diamonds to Neptune
2013-09-12
Washington, D.C.—Hydrocarbons from the Earth make up the oil and gas that heat our homes and fuel our cars. The study of the various phases of molecules formed from carbon and hydrogen under high pressures and temperatures, like those found in the Earth's interior, helps scientists understand the chemical processes occurring deep within planets, including Earth.
New research from a team led by Carnegie's Alexander Goncharov hones in on the hydrocarbon methane (CH4), which is one of the most abundant molecules in the universe. Despite its ubiquity, methane's behavior ...