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5 December 2013 11:26 am ,
Vol. 342 ,
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Bleach May Kill Brain Cells in Alzheimer's
15 June 1999 7:30 pm
Scientists have fingered a new suspect in the brain cell deaths that underlie Alzheimer's disease. According to test-tube findings reported in today's issue of Biochemistry, protein plaques that riddle victims' brains appear to produce hydrogen peroxide, or bleach, which is toxic to nerve cells. Shutting off this reaction may be a way to slow the progressive disorder, which is the fourth leading cause of death in Western countries.
Ever since the days of Alois Alzheimer, neuroscientists have known that a protein called amyloid globs together in plaques in the brains of Alzheimer's patients. But debate still rages over whether the plaques themselves kill brain cells, the loss of which leads to dementia.
A few years ago researchers began to find hydrogen peroxide (H2O2), a corrosive compound that can kill neurons, in patients' brains; how it got there was a mystery. Most scientists assumed it was produced by some reaction in the dying cells. Ashley Bush, a psychiatrist at Harvard Medical School in Boston, and colleagues wondered whether the hydrogen peroxide might come from the plaques themselves. In test tubes, the researchers mixed solutions of amyloid protein with solutions of copper and iron ions, which are plentiful in the brain. They discovered that the amyloid protein bound the metal ions and gave off hydrogen peroxide as a byproduct. The researchers also showed that chelators--chemicals that capture metals--are capable of shutting down hydrogen peroxide production almost completely.
The findings are the first evidence "that plaques can generate a neuron-killing chemical," says Vassilis Koliatsos, a neuropathologist at The Johns Hopkins University School of Medicine. Bush's team next plans to see whether the plaques pump out H202 in the body. If so, he says, chelating compounds that specifically tie up copper and iron could be tested as potential Alzheimer's drugs.