ScienceDaily (July 26, 2012) Roofers and road construction workers who use hot asphalt are exposed to high levels of polycyclic aromatic hydrocarbons (PAHs). A University of Colorado Cancer Center study published this week in the British Medical Journal Open shows that roofers have higher PAH blood-levels after working a shift and that these high levels of PAHs are linked with increased rates of DNA damage, and potentially with higher cancer risk.

"We've known for some time that roofers and road workers have higher cancer rates than the general population, but we also know roofers have a higher rates of smoking, alcohol use and higher UV exposure than the general population. It's been difficult to pinpoint the cause of higher cancer rates -- is it due to higher PAHs or is it due to lifestyle and other risk factors?" says Berrin Serdar, MD, PhD, investigator at the CU Cancer Center and assistant professor of environmental and occupational health at the Colorado School of Public Health.

Her study, completed with colleagues at the University of Miami, studied 19 roofers from four work sites in Miami-Dade County. Participants' urine samples, provided before and after a 6-hour shift, showed that after acute exposure to hot asphalt, PAH biomarkers were elevated. Overall, biomarkers of PAH exposure and oxidative DNA damage (8-OHdG) were highest among workers who didn't use protective gloves and workers who also reported work related skin burns, pointing to the role of PAH absorption through skin.

"PAHs are a complex mixture of chemicals some of which are known human carcinogens. They are produced by incomplete combustion of organic materials and exist in tobacco smoke, engine exhaust, or can come from environmental sources like forest fires, but the highest exposure is among occupational groups, for example coke oven workers or workers who use hot asphalt," Serdar says.

"We can't say with certainty that exposure to hot asphalt causes roofers' increased cancer rate," Serdar says, "but that possibility is becoming increasingly likely. Hot asphalt leads to PAH exposure, leads to higher PAH biomarkers, leads to increased DNA damage -- we hope to further explore the final link between DNA damage due to PAH exposure and higher cancer rates in this population."

Serdar and colleagues at the CU Cancer Center have initiated a wider study of roofers in the Denver metropolitan area. This study will simultaneously investigate air, blood, and urine levels of PAHs and their link to DNA damage in samples collected over a workweek.

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by University of Colorado Denver. The original article was written by Garth Sundem.

More here:
DNA damage in roofers due to PAH exposure, possible cancer link

26 July 2012 Last updated at 03:59 ET

Police in Mauritius have begun DNA testing of hotel staff working on the day Michaela McAreavey was murdered.

Detectives are at the former Legends hotel to collect samples from 216 employees.

These will be compared with traces left at the scene of the honeymoon suite where the 27-year-old from County Tyrone was killed in January 2011.

A new investigation team was set up after two former hotel workers were acquitted of murder earlier this month.

The BBC's Yasine Mohabuth said detectives were also taking fingerprints "for comparison with those found at the scene of crime".

Hotel director Brice Lunot told independent station Radio Plus: "The hotel management is relieved at the decision to reopen the investigation."

Mauritius foreign affairs minister, Arvin Boolell, has promised that "no stone will be left unturned" until these responsible for Mrs McAreavey's death were found.

Former hotel workers Sandip Moneea and Avinash Treebhoowoon were cleared of Mrs McAreavey's killing by a jury at the Supreme Court in the capital Port Louis.

View post:
DNA tests in new Michaela inquiry

The human family tree just got another mysterious branch, an African sister species to the heavy-browed Neanderthals that once roamed Europe.

While no fossilized bones have been found from these enigmatic people, they did leave a calling card in present-day Africans: snippets of foreign DNA.

Theres only one way that genetic material could have made it into modern human populations.

Geneticists like euphemisms, but were talking about sex, said Joshua Akey of the University of Washington in Seattle, whose lab identified the mystery DNA in three groups of modern Africans.

These genetic leftovers do not resemble DNA from any modern-day humans. The foreign DNA also does not resemble Neanderthal DNA, which shows up in the DNA of some modern-day Europeans, Akey said. That means the newly identified DNA came from an unknown group.

Were calling this a Neanderthal sibling species in Africa, Akey said. He added that the interbreeding probably occurred 20,000 to 50,000 years ago, long after some modern humans had walked out of Africa to colonize Asia and Europe, and around the same time Neanderthals were waning in Europe.

The find offers more evidence that for thousands of years, modern-looking humans shared the Earth with evolutionary cousins who later died out. And whenever the groups met, whether in Africa or Europe, they did what came naturally they bred. In fact, hominid hanky-panky seems to have occurred wherever humans met others who looked kind of like them a controversial idea until recently.

In 2010, researchers from the Max Planck Institute for Evolutionary Anthropology in Germany announced finding Neanderthal DNA in the genomes of modern Europeans.

Barrel-chested people whose thick double brows, broad noses and flat faces set them apart from modern humans, Neanderthals disappeared around 25,000 to 30,000 years ago.

Another mysterious group of extinct people recently identified from a 30,000-year-old finger bone in Siberia known as the Denisovans also left some of their DNA in modern-day Pacific Islanders.

Read more:
Neanderthal-type species once roamed Africa, DNA shows

A federal appeals court will take a second look at a California law that requires police to collect DNA from people who are arrested on suspicion of felonies, regardless of whether they are convicted.

A majority of judges on the U.S. 9th Circuit Court of Appeals voted Wednesday to reconsider a split decision by a three-judge panel that had upheld the program in February.

The court's decision to ask an 11-judge panel to consider the case was a setback for prosecutors, who have defended the DNA collection as a vital crime-fighting tool.

Once a person is swabbed, his or her DNA profile is placed in a criminal database, where it can be compared with DNA profiles obtained from evidence left at crime scenes. Among those challenging the program were three protesters who were arrested but never convicted of a crime. Two of those challengers were released without being charged.

California voters approved collecting DNA from felony arrestees in 2004, passing Proposition 69 by a wide margin. The state began taking DNA from people arrested on suspicion of felonies in 2009 but immediately faced litigation over whether the collection violated the constitutional rights of people to be free of unreasonable searches and seizures.

In his dissent in February, 9th Circuit Judge William A. Fletcher questioned the effectiveness of the program, observing that many DNA "hits" to crime scene evidence involved suspects who were eventually convicted. The state has long obtained DNA from convicted criminals, a practice courts have upheld.

Although people who are not convicted may apply to have their DNA profile removed from the criminal database, "expungement is a lengthy, uncertain, and expensive process," Fletcher wrote.

The California Supreme Court also is examining the legality of collecting genetic evidence from people before conviction, after a lower state court ruled the practice unconstitutional.

Atty. Gen.Kamala D. Harris, whose office is defending the DNA program, has said that the arrestee DNA collection has solved thousands of crimes. Her office said the potential genetic matches to crime scene evidence rose nearly 51% in the year after authorities began compiling arrestee DNA.

Most states take DNA from at least some felony suspects before conviction, but courts have been split over the constitutionality of the practice. TheU.S. Supreme Courtis considering a ruling out of Maryland that struck down that state's collection of DNA from people never convicted of a crime.

The rest is here:
Federal appeals court to reconsider California DNA-collection law