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[00:01.00]SARAHLONG:This is Sarah Long.
[00:02.30]BOB DOUGHTY:And this is Bob Doughty with Science in the News,a VOA Special English program about recent developments in science.
[00:12.86]Today,we tell about scientists who grew nerve cells from special stem cells.
[00:21.08]We tell about cancer patients who suffer memory loss from chemotherapy treatments.
[00:28.24]And we tell about a rare red panda born in an American zoo.
[00:34.90]SARAH LONG:American scientists have found a way to change bone marrow cells into nerve cells like those found in the brain and the spinal cord.
[00:48.10]The discovery may lead to safe and successful treatments for nerve injuries and brain disorders.
[00:57.24]The work is being done by Ira Black and a team of researchers at the Robert Wood Johnson Medical School in Piscataway,New Jersey.
[01:08.63]Doctor Black said he began the research to study how the body's cells,with the same genetic material,become many different kinds of cells.
[01:20.93]Some become blood cells.Others become liver cells or brain cells.
[01:27.49]Doctor Black wondered how this happened.What caused the cell to change into one kind or another?
[01:36.24]He hoped to learn if scientists could make the same kind of changes in cells.
[01:43.29]BOB DOUGHTY:Special cells called stem cells are produed in bone marrow,the material inside the large bones of the body.
[01:53.51]The stem cells move from the bone marrow to the place where they are needed.
[01:59.78]For example,if the body needs liver cells,stem cells travel to the liver.
[02:06.98]They become liver cells and do all the work that other liver cells do.
[02:13.31]Doctor Black and his team removed stem cells from the bone marrow of rats.
[02:20.36]They put the rat stem cells into laboratory dishes and grew many more of them.
[02:27.91]Then they added a chemical called beta mercaptoethanol.
[02:33.84]Doctor Black had discovered earlier that beta mercaptoethanol had a special effect on cells.
[02:41.81]It seemed to block other chemicals that prevented cells from becoming nerve cells.
[02:49.70]SARAH LONG:Doctor Black said laboratory stem cells treated with beta mercaptoethanol changed within minutes.
[02:58.79]He said they looked exactly like nerve cells
[03:03.17]They began growing long,hair-like parts,just as nerve cells do.
[03:09.73]The researchers found it was possible to change about eighty percent of the stem cells into nerve cells.
[03:18.98]Tests showed that the newly-created nerve cells did all the chemical work that nerve cells usually do.
[03:28.23]Doctor Black transplanted the rat nerve cells he had produced in the laboratory into the brains and spinal cords of living rats.
[03:39.56]The laboratory nerve cells survived for months in the bodies of the rats.
[03:46.28]BOB DOUGHTY:Other scientists praised the discovery.
[03:50.22]One was William Greenough,of the Beckman Institute for Advanced Science and Technology at the University of Illinois.
[04:00.72]Doctor Greenough said the discovery was an important step toward developing new technologies for the repair of a damaged brain.
[04:11.51]He noted that many scientists are working with embryos or animal tissue to try to develop cells to replace damaged human cells.
[04:24.26]But the body's defense system often rejects such foreign cells.
[04:30.14]That would not be a problem with replacement cells grown from a person's own stem cells.
[04:38.02]Scientists say,however,that a huge amount of work must be done before laboratory-produced nerve cells can be used to treat human injury or disease.
[04:51.95]The work done by Doctor Black's team is described in the Journal of Neuroscience Research.
