Friday, October 04, 2002

Can Humans Learn to Regrow Missing Limbs?. New York Times: Science -- In a closetlike room at the "Leg Lab" here, salamanders stare blankly out of clear plastic drinking cups. The lab is so named because many of the animals have had, or will have, a leg cut off. But the salamanders recover, with perfect new limbs growing back in weeks. Salamanders are the superstars of regeneration. They can grow back not only limbs but also tails, parts of their hearts and the retinas and lenses in their eyes. Humans cannot do any of that. So scientists here hope that the salamander's tricks may one day be applied to people. "I really do believe it's just a matter of time before you're going to regenerate an arm or at least a finger," said Dr. David M. Gardiner, a biologist who runs the laboratory at the University of California at Irvine with Dr. Susan V. Bryant, the dean of biological sciences and his wife. "I'd like to see that in my lifetime." Regenerative medicine, regrowing or repairing damaged organs, has become a hot topic. Almost all the attention has focused on stem cells. The idea is to grow stem cells outside the body, turn them into particular types of tissue and transplant them into patients. But a few scientists theorize that a better approach is to induce the same regeneration in people that occurs in salamanders and some other animals. Natural regeneration, which might be accomplished with drugs or genes, would be easier than transplanting, they say. And the tissue would be the patient's own, doing away with the problem of rejection. Even if salamanders' feats cannot be reproduced in humans, those scientists say, studying regenerating animals will at least provide clues for stem cell scientists. (09/26/02) [Synergic Earth News] 6:34:18 AM    comment []

Problem/Solution : Fat Embolus Damages Brain/Fat Filter. The New Scientist -- A new ultrasonic device that removes tiny fat droplets from blood should help prevent brain damage after heart surgery. Two thirds of patients undergoing major heart operations suffer some form of mental impairment afterwards, such as a reduced ability to perform mental arithmetic or remember phone numbers. In half of these patients the problems are permanent. The cause is still controversial, but most researchers think that minute fat droplets lodging in the blood vessels of the brain are responsible. It is thought these block the supply of oxygen to tiny clusters of nerve cells. ... The fat comes from tissues damaged when the chest is cut open. It mixes with the patient's blood in the chest cavity. Surgeons recycle this blood by suctioning it from the chest cavity and re-routing it into the circulation. This avoids the risk of infections inherent in using blood bank blood - but the recycled blood also contains the extra fat. "Fat blockages probably form in every organ, but the brain is the most sensitive," says Henrik Jönsson, head of Erysave, a company in Lund, Sweden. Now he and his colleague Thomas Laurell at the Lund Institute of Technology, have developed a device that uses ultrasound to filter the fat from the blood before it is put back into the patient's body. (10/01/02) [Synergic Earth News] 6:27:12 AM    comment []