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Science Notes / Archaeology, genetics

Colosseum's labyrinth was a frightening place

German archaeologist Heinz-Juergen Beste has spent the past 14 years figuring out a hidden labyrinth underneath Rome's Colosseum, and Smithsonian magazine explains his findings in its January issue. "Its complexity was downright horrifying," Beste said.

The labyrinth, called the hypogeum, contained human-powered machinery that made animals and scenery appear from beneath a wooden floor as if by magic. While Colosseum spectators enjoyed prizes, pastries and wine, the workers in the hypogeum were subjected to disgusting smells and deafening noise, Beste said.

Plus, they could be sentenced to fight to the death in the vast arena if they botched their duties. Following a $1.4 million renovation, the hypogeum opened to the public in October.

-- Washington Post


Scientists seeking ways to make stem cells safe

People have pinned a lot of hopes on pluripotent stem cells which, because of their amazing capacity to morph into other types of cells, have been touted as a potential source for replacement tissues that might someday help reverse spinal cord injuries, Alzheimer's disease and even the damage caused by heart attacks.

But so far only two companies have been granted permission by the Food and Drug Administration to move ahead with trials in humans -- Geron Corp., which is testing a treatment for spinal cord injury, and Advanced Cell Technology, which is testing a treatment for macular degeneration.

A new study, published in the journal Cell Stem Cell, may illustrate part of the reason why. Scientists still haven't figured out how to make sure most stem cells are safe, and won't develop into cancer once implanted in patients.

Stem cell scientists at the University of California, San Diego and the Scripps Research Institute used a high-resolution molecular technique called single nucleotide polymorphism analysis to study stem cell lines. They found that both embryonic stem cells and induced pluripotent stem cells -- adult cells rewound to an embryonic state -- had more genetic abnormalities than other cell types.

Embryonic stem cells tended to have duplications in the genome, while induced pluripotent stem cells were more likely to have deletions. The scientists located specific regions in the genome where the abnormalities were likeliest to arise.

The danger of such genetic abnormalities? They are often associated with cancers, said senior author Jeanne F. Loring, director of the Center for Regenerative Medicine at the Scripps Research Institute.

-- Los Angeles Times