Dr.Osamura is a US-trained pathologist and histochemist who is a Professor Emeritus at Tokai University and now is a Professor and Director of the Center for Diagnostic pathology at International University of Health and Welfare(IUHW), Mita Hospital, Tokyo.

He started his career in histochemistry when he was at the Department of Pathology, University of Colorado, under his mentor Dr.Paul K.Nakane.

He has published more than 470 English papers in peer reviewed journals.

His scientific contributions emphasize endocrine pathology, particularly pituitary tumors, and diagnostic pathology, breast cancers.