American | American Civil War | American Broadcasting Company | American football | African American | American Idol | American Revolutionary War | American Revolution | Society of Jesus | Royal Society | American Association for the Advancement of Science | American Red Cross | National Geographic Society | Doctor of Medicine | American Library Association | American Museum of Natural History | Internal Revenue Service | American Express | American Academy of Arts and Sciences | American League | American Association | American Heart Association | American comic book | American Institute of Architects | American Airlines | American Hockey League | Spanish-American War | Pan American Games | Medicine | American Cancer Society |
Middleton was a member of several national, state, and local medical associations: the American Medical Association, the National Medical Association, the American College of Cardiology, the American Heart Association, the American College of Physians, the American Thoracic Society, the Indiana State Medical Association, the Aesculapian Society, the Indiana Thoracic Society, and the Marion County Medical Society.
He remains licensed to practice medicine in Illinois, Virginia, and Washington, D.C. He is a member of several medical societies such as the American Medical Association, the American Society of Internal Medicine and the American Academy of Medical Directors.