A group of researchers at Sapporo Medical University has successfully restored a cirrhotic liver to a healthy state in rats by administering a newly developed medicine to them, it announced in an electronic edition of a U.S. science journal Monday. The medicine inhibits the formation of collagen, whose excessive secretion causes fibrosis of hepatic cells, according to Yoshiro Niitsu, a professor at the university. The results of the researchers appear in the electronic edition of Nature Biotechnology. The group plans to launch a clinical trial in the United States by the end of this year at the earliest, Niitsu said.