Donald N. Medearis Jr., Wilder distinguished professor of pediatrics at Harvard Medical School (HMS) and retired chief of pediatric services at Massachusetts General Hospital (MGH), died of heart failure on Monday at the age of 70.

Medearis was on the faculty of HMS from 1977 until his retirement in 1995, though he continued working daily until his death.

He specialized in the study of pediatric infectious diseases, according to Linda Dinius, administrative director of pediatric services at MGH.

"His loss was immediately felt," said R. Alan Ezekowitz, the current Wilder professor of pediatrics and Medearis' successor at MGH. "We miss him already."

Medearis was especially interested in children's emergency room care, according to The Boston Globe. In 1993 he published a study indicating that in many cases, care and equipment in emergency rooms are not tailored to children's needs.

Medearis pioneered a combined medical-pediatric residency program at MGH and helped shape the medical school's core curriculum.

"He was an absolutely wonderful man to work for," Dinius said. "The thing closest to his heart was teaching."

Ezekowitz said he believes Medearis will be remembered for "his enormous personal integrity and the loyalty and warmth he engendered."

The medical school has named a research day in Medearis' honor, Ezekowitz said.

In addition, the Butler-Medearis Education Fund will raise money to endow a lectureship in his name, he added.

Originally from Kansas City, Medearis graduated from the University of Kansas and HMS, according to the Globe.

He served on the President's Commission for the Study of Ethical Problems in Medicine under President Jimmy Carter.

Medearis is survived by his wife, Ellen, four children, two brothers, and two grandchildren.

He will be remembered at a memorial service tomorrow at 10 a.m.

The service will be held at Trinity Church in Boston