Bacteria thriving in lightless, low-oxygen, super-salty Antarctic lake may give clues to origins of life -

Bacteria thriving in lightless, low-oxygen, super-salty Antarctic lake may give clues to origins of life - 



A study by polar researchers has revealed an ancient community of bacteria able to thrive in the lightless, oxygen-depleted, salty environment beneath nearly 70 feet (20 metres) of ice in an Antarctic lake, giving insight into the unique ecosystem.

The research, funded by the National Science Foundation and NASA, provides clues about biochemical processes not linked to sunlight, carbon dioxide and oxygen – or photosynthesis.

Emanuele Kuhn/Desert Research InstituteMembers of the 2010 Lake Vida expedition team use a drill inside on the lake’s surface to collect an ice core and brine existing below the lake surface.
The authors of the study say it may explain the potential for life in salty, cryogenic environments beyond Earth, where energy in ecosystems is typically fueled by the sun.

The study, published this week in Proceedings of the National Academy of Science, came out of a collaborative effort of polar researchers from a number of institutions, including the University of Illinois at Chicago, Montana State University and the University of Colorado.

The energy driving bacterial life in Lake Vida, a mostly frozen, brine lake below the Antarctic ice shield, may be derived from chemical reactions between the salt water and the underlying, iron-rich rock, researchers said.

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http://news.nationalpost.com/2012/11/28/bacteria-thriving-in-lightless-low-oxygen-super-salty-antarctic-lake-may-give-clues-to-origins-of-life/

Mammograms Linked With Unnecessary Breast Cancer Treatment

Mammograms Linked With Unnecessary Breast Cancer Treatment



Mammograms have done surprisingly little to catch deadly breast cancers before they spread, a big U.S. study finds. At the same time, more than a million women have been treated for cancers that never would have threatened their lives, researchers estimate.

Up to one-third of breast cancers, or 50,000 to 70,000 cases a year, don't need treatment, the study suggests.

It's the most detailed look yet at overtreatment of breast cancer, and it adds fresh evidence that screening is not as helpful as many women believe. Mammograms are still worthwhile, because they do catch some deadly cancers and save lives, doctors stress. And some of them disagree with conclusions the new study reached.

But it spotlights a reality that is tough for many Americans to accept: Some abnormalities that doctors call "cancer" are not a health threat or truly malignant. There is no good way to tell which ones are, so many women wind up getting treatments like surgery and chemotherapy that they don't really need.

Men have heard a similar message about PSA tests to screen for slow-growing prostate cancer, but it's relatively new to the debate over breast cancer screening.

"We're coming to learn that some cancers – many cancers, depending on the organ – weren't destined to cause death," said Dr. Barnett Kramer, a National Cancer Institute screening expert. However, "once a woman is diagnosed, it's hard to say treatment is not necessary."

He had no role in the study, which was led by Dr. H. Gilbert Welch of Dartmouth Medical School and Dr. Archie Bleyer of St. Charles Health System and Oregon Health & Science University. Results are in Thursday's New England Journal of Medicine.

Breast cancer is the leading type of cancer and cause of cancer deaths in women worldwide. Nearly 1.4 million new cases are diagnosed each year. Other countries screen less aggressively than the U.S. does. In Britain, for example, mammograms are usually offered only every three years and a recent review there found similar signs of overtreatment.

The dogma has been that screening finds cancer early, when it's most curable. But screening is only worthwhile if it finds cancers destined to cause death, and if treating them early improves survival versus treating when or if they cause symptoms.

Mammograms also are an imperfect screening tool – they often give false alarms, spurring biopsies and other tests that ultimately show no cancer was present. The new study looks at a different risk: Overdiagnosis, or finding cancer that is present but does not need treatment.

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http://www.huffingtonpost.com/2012/11/26/mammogram-unnecessary-breast-cancer-treatment-study_n_2192041.html?