Dr. Mammen joined the School of Medicine in 1958 as a Fulbright scholar in the department of physiology and pharmacology. An outstanding scientist, educator, administrator and clinician, Dr. Mammen was internationally recognized for his expertise in the field of hemostasis. He was a leading authority in the use of mini-dose heparin in prophylactic treatment of deep vein thrombosis.

Dr. Mammen served as Wayne State University's dean of the College of Pharmacy from 1974 to 1982 before retiring from clinical practice in 1996. He returned in 2000 to serve as Interim Dean for the School of Pharmacy and Health Sciences. During his time as dean, Dr. Mammen designed the first interdisciplinary pathophysiology course and offered a curriculum in which allied health professionals made hospital rounds with physicians.

A beloved professor, Dr. Mammen mentored and educated many medical students and Ph.D. candidates and earned their deepest respect and gratitude. He was honored by his students five times with the esteemed LAMP award, which is presented each year to the basic science faculty member who provides the most the most valuable and rewarding learning experience.