How pleasant...
Posted: 1/27/2005, 10:12 am
North Korea is believed to have one or two nuclear weapons and possibly more than eight.
Dabekk wrote:I just don't understand the U.S. They attack Iraq because of the posibility that the might have WMDs, and then there's North Korea who's saying 'LOOK AT US WE HAVE WMDs' and the U.S. doesn nothing.
Cass wrote:I used to think that too. But then someone changed my mind. All I'll say is, I think that that's rationalizing. Like, hey I just accidentally rammed into the back of that guys car, I might as well take some stuff out of it too....
U of T team discovers stem cell jackpot
Umbilical jelly loaded with cells
Hope for tissue repair, transplants
JOSEPH HALL
STAFF REPORTER
University of Toronto researchers have discovered a treasure-trove of stem cells that could one day help repair broken limbs and ease bone marrow transplants.
The source: a region of the umbilical cord that holds an abundant supply of connective-tissue stem cells — the basic building blocks for the body's bone, fat and ligament tissues.
The implications include a range of possible new treatments to repair torn ligaments and fractured bones, or to enhance the effectiveness of bone marrow transplants for leukemia patients.
The findings may also spur greater efforts to preserve the umbilical cords of newborns as a source of treatment in later years for the child, or possibly others.
"We're very excited by this, that's for sure," said J.E. Davies, of the UofT's Institute of Biomaterials and Biomedical Engineering.
Davies is lead author of a paper describing the research, to be published this week in the journal Stem Cells.
"You can anticipate using these as a source of cells to help re-grow that bone ... or connective tissue in the knee ... which has been damaged in an accident," he said.
While pre-clinical animal studies are yet to begin, Davies says treatments might be available to humans in the next five years.
Davies says the new stem cell source could also be used for treatment of diseases such as leukemia and lymphoma, which often require bone marrow transplants.
These transplants, which usually involve the injection of bone marrow from a compatible donor, transfer healthy blood-creating stem cells into patients whose own marrow has been compromised or destroyed.
The connective tissue stem cells can interact with their blood-creating cousins to enhance the effectiveness of a marrow transplant, Davies said.
"(They) talk to each other and they depend upon each other for their survival and proliferation," he said.
Also, Davies said, the connective tissue stem cells do not seem to have the cellular markers that would identify them as foreign, which means they should not cause an immune rejection if donated to another person.
"This could be a huge benefit to the increasing number of patients who are having or are needing bone marrow transplants," Davies says.
"To get such a population (of connective tissue stem cells) easily and being able to bank such a population, particularly for other people ... that would be very exciting."
Known as mesenchymal cells, the bone-building brand of stem cells is the progenitor of all the body's connective tissues, which also include cartilage and some muscles.
But the cells have previously been extremely hard to locate, said Davies.
They can be found in concentrations of about one in 10,000 cells in the bone marrow of young children, and one in 100,000 in adult marrow.
But in the umbilical cord jelly now being mined by the UofT team, the concentration is one in 300. Known as Wharton's Jelly, it surrounds the three umbilical cord blood vessels connecting the fetus and mother. The jelly helps prevent the vessels from kinking — much like a garden hose might — as the embryo floats about the womb.
The U of T team used donated cords from full-term pregnancies.
The richest concentration of stem cells is the human embryo, whose basic cells can morph into any of the body's 260 varieties of specialized cells, such as brain, liver, bone and blood.
But ethical concerns about research into embryonic stem cells have pushed researchers to focus on two other sources of these chameleon cells — the adult body, where they are present, but rare, and in the umbilical cord.
Blood from the umbilical cord is already recognized as a source of blood-forming stem cells, and an increasing number of parents choose to have a child's umbilical cord frozen and stored as insurance against future diseases in their child — or other family members.
And the use of bone-building stem cells could help boost the effectiveness of that stored umbilical cord blood, Davies said.
Davies suggested that such a storage program could be available for the umbilical jelly material too.
"This is an opportunity to say, let's not just bank the (umbilical) cord blood, but let's bank these other cells too because they are a very rich population ... which can benefit the survival and function of the (blood stem) cells," he said.
The stored cells could also be used by its owner in case of future accidents where bone or ligament damage occurs, he says.
"If they have a serious road traffic accident, they want some (connective tissue) cells to heal a broken bone, then this could be a source of those cells."
Dr. Allen Eaves, a senior scientist at the B.C. Cancer Institute, called the discovery of the new source for the stem cells exciting.
"The cord is normally discarded after birth and this is a non-controversial source of stem cells, and this makes it particularly attractive," Eaves said from Vancouver.
"More study is really needed to try and optimize the use of these cells," said Eaves.
"There's no question they have some therapeutic use."