Study Links Heavy Diesel Exhaust to Lung Cancer

Worldwide - There's new evidence that exposure to exhaust from diesel engines increases the risk of lung cancer.

Diesel exhaust has long been classified as a probable carcinogen. But the 20-year study from the National Cancer Institute took a closer look by tracking more than 12,000 workers in certain kinds of mines — facilities that mined for potash, lime and other nonmetals. They breathed varying levels of exhaust from diesel-powered equipment, levels higher than the general population encounters.

The most heavily exposed miners had three times the risk of death from lung cancer compared to workers with the lowest exposures, said the study released Friday by the Journal of the National Cancer Institute.

But even workers with lower exposures had a 50 percent increased risk, wrote lead author Debra Silverman, an NCI epidemiologist.

"Our findings are important not only for miners but also for the 1.4 million American workers and the 3 million European workers exposed to diesel exhaust, and for urban populations worldwide," Silverman wrote.

She pointed to some highly polluted cities in China, Mexico and Portugal that in past years have reported diesel exposure levels that over long periods could be comparable to those experienced by miners with lower exposures.

Litigation from some mining companies had delayed release of the study findings.

A separate industry group not involved in that litigation said Friday that the study looked back at mines using decades-old equipment, and there's far less pollution from diesel engines today.

"Diesel engine and equipment makers, fuel refiners and emissions control technology manufacturers have invested billions of dollars in research to develop and deploy technologies and strategies that reduce engine emissions, now ultimately to near zero levels to meet increasingly stringent clean air standards here in the United States and around the world," said Allen Schaeffer of the nonprofit Diesel Technology Forum.

Teardrop Protein Shown to Have Jaws

ScienceDaily — A disease-fighting protein in our teardrops has been tethered to a tiny transistor, enabling UC Irvine scientists to discover exactly how it destroys dangerous bacteria. The research could prove critical to long-term work aimed at diagnosing cancers and other illnesses in their very early stages.

Ever since Nobel laureate Alexander Fleming found that human tears contain antiseptic proteins called lysozymes about a century ago, scientists have tried to solve the mystery of how they could relentlessly wipe out far larger bacteria. It turns out that lysozymes have jaws that latch on and chomp through rows of cell walls like someone hungrily devouring an ear of corn, according to findings that will be published Jan. 20 in the journal Science.

"Those jaws chew apart the walls of the bacteria that are trying to get into your eyes and infect them," said molecular biologist and chemistry professor Gregory Weiss, who co-led the project with associate professor of physics & astronomy Philip Collins.

The researchers decoded the protein's behavior by building one of the world's smallest transistors -- 25 times smaller than similar circuitry in laptop computers or smartphones. Individual lysozymes were glued to the live wire, and their eating activities were monitored.

"Our circuits are molecule-sized microphones," Collins said. "It's just like a stethoscope listening to your heart, except we're listening to a single molecule of protein."

It took years for the UCI scientists to assemble the transistor and attach single-molecule teardrop proteins. The scientists hope the same novel technology can be used to detect cancerous molecules. It could take a decade to figure out but would be well worth it, said Weiss, who lost his father to lung cancer.

"If we can detect single molecules associated with cancer, then that means we'd be able to detect it very, very early," Weiss said. "That would be very exciting, because we know that if we treat cancer early, it will be much more successful, patients will be cured much faster, and costs will be much less."

The project was sponsored by the National Cancer Institute and the National Science Foundation. Co-authors of the Science paper are Yongki Choi, Issa Moody, Patrick Sims, Steven Hunt, Brad Corso and Israel Perez.