History
Dr. Christensen colloborated with his fellow medical professionals, Doctors Siegel, Patten, and Mayer, on a research project that was attempting to find a cure for an unspecified medical condition. The group attempted to recruit Doctor Stephen Strange to their cause, Siegel acting as the spokesman while Christensen stood by silently, but they were rebuffed.
Notes
Christensen goes unnamed in Strange Tales #115, his first and only appearance to date; he is named in the novel Doctor Strange: Nightmare. As he does not speak in either the comic or novel, and no description is given in the novel, at this point it is impossible to determine which doctor is Christensen.