Creighton University has announced plans to sell its struggling medical center in Omaha to a regional health care network. The university, which sold off a large share of the hospital's ownership to another health care company, Tenet, in 1995, said Wednesday that Alegent Health would buy the entire Creighton University Medical Center, and that Alegent would become the university's primary partner for its medical and other health professions students. The university did not disclose the terms of the deal.