A Chicago Heights physician I has recently completed a one-year medical internship at St.| Mary of Nazareth hosiptal in Chicago.He is Dr. RONALD C. JES-SEN, son of Mr. and Mrs. MARTIN JESSEN, 180 East Seventhplace. Dr. Jessen will now begin his residency in pathology i at the Illinois Research hospital in Chicago.Dr. Jessen, who married the former ZELMA BURTON of Beaverdam, Ky., graduated from Bloom high school in 1946. He received his bachelor of arts degree from Illinois college in Jacksonville; and his doctor of medicine from the University of Illinois college of! medicine.* * ♦