Frozen heart back to life

Scientists have succeeded in bringing a deep-frozen heart taken from a rat back to life, according to a report in New Scientist today.

The achievement by researchers from the University of Pretoria in South Africa is seen as a significant step towards storing transplant organs in deep freeze. Previous attempts have been frustrated by the fact that water expands when it freezes, rupturing cell membranes. The researchers solved the problem with a "cryoprotectant" liquid which is non-toxic and does not damage cells when it freezes. They plan to transplant a defrosted pig's heart into a live animal by the end of the year.