Chinese doctors report that they have successfully transplanted the cells of pig livers into 12 patients suffering from liver failure since last September, and that "80 percent of the patients" have either recovered completely or have improved.

The operations took place at Gulou Hospital in Nanjing, capital of east China's Jiangsu Provice, and involved researchers from the Life Research Institute of Nanjing University.

The 12 patients were all between 30 and 40 years of age, according to hospital officials.

The hospital provided no further details on the transplant, making it difficult to assess the significance of the Chinese procedure.

U.S. doctors have used pig livers as a "bridge" to keep a patient alive while awaiting a human liver to become available for transplantation on several occasions, and researchers in the U.S. and Europe are seeking to develop genetically altered pig livers that may someday be used in place of human livers.

Other sources: Xinhua, AFP