In North Carolina, there are nearly 4,500 nurse practitioners, who are increasingly on the front lines of the American health care system. They can write prescriptions and make diagnoses under the supervision of doctors. Most are nurses who have earned a master's degree to increase their training in direct patient care. But starting in the fall, those seeking to be advanced nurses will have the option - and eventually, the requirement - to gain more education. Last month, the UNC system's Board of Governors approved the Doctor of Nursing Practice, or DNP degree, for six public campuses: East Carolina, UNC-CH, UNC-Charlotte, UNC-Greensboro, Winston-Salem State University and Western Carolina University. Two private universities, Duke and Gardner-Webb, already offer the more advanced degree.