The technique developed by University of California-San Francisco researchers builds on previous research last year by Dr. Shinya Yamanaka and then confirmed this spring by Yamanaka's team and, in independent studies, by scientists at the Massachusetts Institute of Technology, Harvard and UCLA.

The UCSF team said their new finding should accelerate research aimed at improving the original strategy, as well as increasing its potential use for studying disease development and creating patient-specific stem-cell based therapies.

"The new technique removes a major technical hurdle that has likely discouraged many labs around the world from carrying out studies on the strategy," said the study's senior author Ramalho-Santos.

The work by Ramalho-Santos, Dr. Robert Blelloch of the UCSF Institute for Regeneration Medicine and their colleagues is available on-line as an immediate early publication in the journal Cell Stem Cell.