Oklahoma State University Medical Center is terminating its management agreement with St. John Health System, meaning Jan Slater will leave her CEO position at the OSU hospital. The medical center trust approved the decision Thursday at its regular meeting. The decision to end St. John's management of the medical center was mutual but at the request of St. John. Because the two hospitals operate in the same marketplace, there were conflict-of-interest issues, said Jerry Hudson, chairman of the trust. Despite problems in the past, the hospital is now in a more stable position than when the agreement with St. John was necessary, he said.