Science Briefs: Duke researchers invent living patch for damaged hearts

News ServicesMay 12, 2013 

Living patch invented for damaged hearts

Duke University biomedical engineers have grown three-dimensional human heart muscle that acts just like natural tissue. This advancement could be important in treating heart attack patients or for testing new heart disease medicines.

The “heart patch” grown in the lab from human cells conducts electricity at about the same speed as natural heart cells, and it “squeezes” appropriately. Earlier attempts to create functional heart patches have largely been unable to overcome those obstacles.

The source cells used by the Duke researchers were human embryonic stem cells. These cells, given the right chemical and physical signals, can be coaxed by scientists to become any kind of cell – in this case, heart muscle cells.

“This is the closest man-made approximation of native human heart tissue to date,” said Nenad Bursac of Duke’s Pratt School of Engineering. The results of his research were published online in the journal Biomaterials. Duke University

Insights on dinosaur predecessors

Newly discovered fossils from after Earth’s largest mass extinction 252 million years ago reveal a lineage of animals thought to have led to dinosaurs in Africa.

The fossils are from 10 million years later – but millions of years before dinosaur relatives were seen in the fossil record elsewhere on Earth.

“After the extinction,” said University of Washington paleontologist Christian Sidor, “animals weren’t as uniformly and widely distributed as before. We had to go looking in some fairly unorthodox places.” Sidor is lead author of a paper on the subject; it appears in the journal Proceedings of the National Academy of Sciences.

The insights come from seven fossil-hunting expeditions in Tanzania, Zambia and Antarctica funded by the National Science Foundation.

Just 7 percent of species were found in two or more regions.

The snapshot of life 10 million years after the extinction reveals that, among other things, archosaurs roamed in Tanzanian and Zambian basins. Archosaurs, whose living relatives are birds and crocodilians, are of interest to scientists because it’s thought that they led to animals such as Nyasasaurus parringtoni, a dog-sized creature with a 5-foot-long tail that could be the earliest dinosaur. National Science Foundation

Protein is key to detecting odors

Researchers at Monell Chemical Senses Center in Philadelphia, with collaborators, have identified a protein that is critical to the ability of mammals to smell. Mice engineered to lack the Ggamma13 protein in their olfactory receptors were functionally unable to smell. The findings may lend insight into the underlying causes of certain smell disorders in humans.

The findings were published in the Journal of Neuroscience.

Odor molecules entering the nose are sensed by a family of olfactory receptors. Inside the receptor cells, a complex cascade of molecular interactions converts information to ultimately generate an electrical signal that tells the brain an odor has been detected.

In behavioral tests, control mice with an intact sense of smell were able to detect and retrieve a piece of buried food in less than 30 seconds. Mice lacking Ggamma13 in their olfactory cells required more than eight minutes to perform the same task.

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