( imens obtained for amniocentesis a pro...)Scientists discover new, readily available source of stem cells

Atala said a bank with 100,000 specimens theoretically could supply 99 percent of the U.S. population with perfect genetic matches for transplantation. There are more than 4 million live births each year in the United States.

In addition to being easily obtainable, the AFS cells can be grown in large quantities because they typically double every 36 hours. They also do not require guidance from other cells (termed "feeders") and they do not produce tumors, which can occur with certain other types of stem cells. The scientists noted that specialized cells generated from the AFS cells included all three classes of cells found in the developing embryo - termed ectoderm, mesoderm, and endoderm. In their high degree of flexibility and growth potential, the AFS cells resemble human embryonic stem cells, which are believed capable of generating every type of adult cell.

"The full range of cells that AFS cells can give rise to remains to be determined," said Atala. "So far, we've been successful with every cell type we've attempted to produce from these stem cells. The AFS cells can also produce mature cells that meet tests of function, which suggests their therapeutic value."

The functional tests included implanting neural cells created from AFS cells into mice with a degenerative brain disease. The cells grew and "re-populated" the diseased areas. In addition, bone cells produced from the stem cells were successfully used to grow bony tissue in mice, and liver cells were able to secrete urea, which the liver produces from ammonia.

The potential to generate a broad range of mature cell types is why many scientists believe stem cells have promise to replace damaged cells and
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Source:Wake Forest University Baptist Medical Center