National Medical Enterprises, Los Angeles, has appointed William S. Banowsky an executive vice president. Banowsky, 52, has served as an outside director of the company since 1977. Banowsky most recently served as president of the Texas Superconducting Super Collider Authority, where he led the effort to qualify Texas as the site for the $5-billion federal, atom-smasher project. The winner will be announced next month. Banowsky previously served as president of Gaylord Broadcasting Co., president of the University of Oklahoma and president of Pepperdine University.