However, the application of the liver stem cell transplant was restricted by many related clinical problems.

目前仍有许多临床相关问题限制干细胞移植的应用。

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Mr Bush said finance would be restricted to existing stem cell lines from embryos that had already been destroyed.

BBC: Bush backs stem cell research

In the U.S. stem cell research has been restricted to private institutions since the Bush administration banned federally funded research in 2001.

CNN: Cloning success hailed, feared