Body & Brain

Heart attacks worse in the morning, plus remembering dreams, lung stem cells and more in this week’s news

Surgical-center colonoscopies stack up
Colonoscopies performed at outpatient surgical centers are as safe as those done in hospitals, researchers at Emory University in Atlanta reported May 10 at the Digestive Disease Week meeting in Chicago. More than 174,000 Medicare records from 1992 to 2007 showed a 30-day complication rate of 3.4 percent from hospital colonoscopies and 2.4 percent from those done in outpatient surgical centers. After accounting for differences among patients, these complication rates were similar. The share of colonoscopies done in hospitals fell from 69 percent to 47 percent over that span while surgical centers saw an increase in colonoscopies from 10 percent to 48 percent. A shrinking number of the procedures are still done in doctors’ offices. Nathan Seppa

Morning heart attacks worse
A heart attack that strikes between 6 a.m. and noon does more damage than one that hits at any other time of day, scientists report in an upcoming issue of Heart. A research team in Spain analyzed data on 811 heart attacks and found that 269 had occurred in the morning, 240 between noon and 6 p.m., 161 from 6 p.m. to midnight and 141 during the wee hours. Damage to the heart muscle was about 20 percent greater from morning heart attacks than from those during the other times. The researchers say the findings call for further study into the role played by enzymes in the body that fluctuate with the body clock. —Nathan Seppa

Remembering dreams
If you’re worried about Leonardo DiCaprio planting thoughts into your dreams, certain types of brain activity may predict whether you’ll be able to remember his attempts at inception in the morning. People with just the right kind of brain pulses more frequently remember dreams when they wake up, a team of researchers in Italy reports in the May 4 Journal of Neuroscience. Individuals are better able to recall their dreams if particular brain waves called theta waves are more active in the frontmost regions of the brain before waking from REM sleep. Similar brain patterns may help individuals remember events during the daytime, too. —Daniel Strain

Mice act out dreams
Researchers have created a mouse version of a condition in which people physically act out their dreams. Unlike normal mice, who sleep peacefully curled up, mice with a particular neurological mutation thrash around during REM sleep — running, jerking and chewing, researchers report May 11 in the Journal of Neuroscience. Most people with a similar condition known as REM sleep behavior disorder, or RBD, go on to develop Parkinson’s or another dementia. So studying these mice in the lab might help scientists better understand the strange sleep disorder, study authors Patricia Brooks and John Peever of the University of Toronto write. The mice with the sleep disorder lack a working copy of a protein that detects nerve cell messages. —Laura Sanders

Lung stem cells
Researchers have for the first time spotted tiny pockets of what look to be lung stem cells deep inside human respiratory tracts. These masters of disguise can form a wide variety of lung tissue in live animals, an international team of researchers reports online May 12 in the New England Journal of Medicine. As a test of versatility, the team injected the human stem cells into mice with damaged lungs. In about two weeks, the cells formed complex and seemingly functional respiratory structures in the mice, replacing about 30 percent of lost tissue. —Daniel Strain

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