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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
- About Us
15 June 2006 (All day)
Hundreds of tons of engineered, microscopic particles enter the environment every year, yet little is known of their biological effects. Now, a study of ultrafine particles of titanium dioxide (TiO2)--used in manufacturing, personal care and food products, and as drug carriers--indicates that even low concentrations can produce harmful "free radicals" in brain cells. The findings underscore the need to learn more about how such tiny particles interact with living tissues, the researchers say.
Previous studies have revealed that many nontoxic materials become harmful at particle sizes of less than 100 nanometers. Specifically, they can trigger the production of biologically reactive, oxygen-containing molecules such as free radicals. In addition, some types of particulate matter can enter the brain once they get into the bloodstream. Little is known about the biological effects of TiO2, but its widespread use and distribution means that humans and other animals could be widely exposed.
To investigate the biological effects of TiO2, Bellina Veronesi, a neurotoxicologist with the U.S. Environmental Protection Agency in Research Triangle Park, North Carolina, and her colleagues exposed mouse microglia--cells that protect the brain from invaders such as viruses and foreign chemicals--to a solution containing minute concentrations of TiO2. The microglia engulfed the particles and released bursts of reactive oxygen molecules for 2 hours. This didn't damage the microglia, but Veronesi says prolonged exposure to these compounds can damage neurons. In fact, a similar mechanism is thought to underlie some cardiovascular and neurodegenerative diseases, including Parkinson's and Alzheimer's, the researchers note in their report, published online 7 June in Environmental Science & Technology.
Environmental toxicologist Günter Oberdörster of the University of Rochester in New York says the research is a "good proof of principle," but without further studies it would be premature to conclude that TiO2 damages the brain. "The general message is that we should take these results seriously and be very careful with nanoparticles," he says.