1.   Tumors of the islet cells lead to severe hypoglycemia.

2.   And then the new islet cells would have to be protected from the underlying disease process that caused the diabetes in the first place.

3.   Animals such as pigs are being studied as a source of islet cells, as well as stem cells.

4.   At UMass, Rossini has been working for years on the thorny problem of how to achieve tolerance, or the state in which islet cells would be accepted.

5.   At the National Institutes of Health, scientists have coaxed mouse embryonic stem cells to assemble into hormone-producing clusters of pancreatic islet cells.

6.   Both patients must return later this year for a second transplant of islet cells, which they hope will completely remove their need to inject insulin.

7.   - Attempts to modify the immune system to prevent rejection of transplanted pancreatic islet cells to treat diabetes.

8.   A final challenge is to find an alternate source of islet cells.

9.   A way around the donor shortage is to grow islet cells in the laboratory, but this sounds much easier than it is.

10.   Affected islet cells produce less insulin, thereby worsening the disease.