Archive for May 2011
AN ANCIENT CELLULAR PROGRAM to protect cells when oxygen is low seems crucial for the production of new brain cells.
For more than two billion years on this planet, O2 has been the go-to gas for generating efficient cellular energy. But life on Earth never takes oxygen for granted. “When it runs low, cells swiftly adapt,” says cell biologist Celeste Simon.
This ancient adaptive reaction, known as the low-oxygen, or hypoxia, response, typically involves a cascade of protective changes in cells: protein synthesis drops and cells switch to a less efficient process of energy production that doesn’t require oxygen. But organisms have evolved uses for the hypoxia response that are not merely protective.
Simon, an HHMI investigator at the University of Pennsylvania, recently found evidence that the response is crucial for maintaining the health of stem cells in the hippocampus, a key memory region of the brain. The discovery could alter our understanding of a host of stem cell-related brain conditions.
Researchers create carbon nanotubes that mimic natural tissue and can regenerate heart cells in a dish.
A conductive patch of carbon nanotubes can regenerate heart tissue growing in a dish, according to preliminary research from Brown University. The patch, made of tiny chains of carbon atoms that fold in on themselves, forming a tube, conducts electricity and mimics the rough surface of natural tissue. The more nanotubes the Brown researchers added to the patch, the more cells around it were able to regenerate.
Have a heart: Brown University researchers have created a tiny patch made out of carbon nanotubes that they hope will someday help regenerate heart cells.
Credit: Thomas Webster at Brown University
An inexpensive dietary supplement appears to help prevent the serious pregnancy complication preeclampsia in high-risk women, according to a new study.
But researchers say the effect in lower-risk pregnancies remains to be determined.
In the study from Mexico, women who ate daily food bars containing the amino acid L-arginine and antioxidant vitamins during pregnancy had a much lower incidence of preeclampsia than women who ate bars containing the antioxidant vitamins alone or bars containing neither supplement
The human brain has yet to explain the origin of one its defining features — the deep fissures and convolutions that increase its surface area and allow for rational and abstract thoughts.
An international collaboration of scientists from the Yale School of Medicine and Turkey may have discovered humanity’s beneficiary — a tiny variation within a single gene that determines the formation of brain convolutions — they report online May 15 in the journal Nature Genetics.
On the left, the occipital region of a normal human brain is circled. On the right, the same area of the brain of a subject with mutation of LAMC3 gene is smooth, and lacks normal folds and convolutions. (Credit: courtesy of Yale University) Read the rest of this entry »
Cells that have been reprogrammed to grow into different types of tissue might be rejected by the body — even when they are transplanted into the individual from whom they are made, researchers report in a study published today in Nature1.The study was led by Yang Xu, a molecular biologist at the University of California, San Diego. It will shake up the regenerative-medicine field, because until now, most scientists have assumed that reprogrammed cells made from an individuals own tissue could be safely transplanted back into the same person.
Neural stem cells can do a lot, but not everything. For example, brain and spinal cord cells are not usually generated by neural stem cells of the peripheral nervous system, and it is not possible to produce cells of the peripheral nervous system from the stem cells of the brain. However, researchers from the Max Planck Institute for Brain Research in Frankfurt and the Max Planck Institute of Immunobiology and Epigenetics in Freiburg have now succeeded in producing central nervous system cells from neural stem cells of the peripheral nervous system. They found that if peripheral stem cells are maintained under defined growth conditions, they generate oligodendrocytes, which form the myelin layer that surrounds the neurons found in the brain and spinal cord.
Transplantation of reprogrammed neural stem cells into the brains of genetically modified mice, which cannot form myelin. The stem cells develop oligodendrocytes (green), which form myelin (red). Read the rest of this entry »
Talk between the brain’s decision-making center, or frontal cortex, and other brain regions might distinguish aware individuals from those stripped of conscious thought. Identifying such signaling malfunctions could speed the diagnosis of vegetative states and give scientists insight into such devastating disorders, an international team of researchers reports May 12 in Science.
Today, diagnosing a vegetative brain is an uncertain enterprise, says John Whyte, director of the Moss Rehabilitation Research Institute in Elkins Park, Pa. Patients classified as vegetative can’t act in any purposeful way under any observable circumstances. Patients deemed minimally conscious, however, show some capacity to understand and interact with the world — for instance, by moving a finger on command. Distinguishing between the two can take weeks of behavioral testing, and misdiagnoses are common.
The flow of information in the brain might be a crucial element of why patients in vegetative states can’t move or speak on their own accord
Image credits: University of Liège / © comascience.org