Dena Dolfi Stura of 5 James St.;Belle Vernon;died suddenly on Thursday;Oct.20;1983;at 10:56 a.m. in Mon Valley Hospital;Inc.    She was 83.   Born May 7;1900;in Pistoria;Italy;she was the daughter of the late Amelio and Irene Valdiserri Dolfi.  In addition to her parents; Mrs.Stura was preceded in death by three brothers;Fred;Amos and William Dolfi;and a sister;Pauline Fornacari.  Surviving are her husband;Alexander Stura;two sons;John Stura and George (Fuzzy) Stura;both of Belle Vernon;two daughters;Mrs.William (Norma) Wolf of Lawton;Okla.;and Mrs.Frank (Nancy) Rizzuto of Monessen;a brother;George Dolfi;and two sisters;Mrs.Mary Stura and Mrs.Brian (Eva) Baso;all of Clairton;seven grandchildren and three great-grandchildren.  Mrs.Stura was a member of St.Sebstian Church of Belle Vernon.  She had been a resident of the Belle Vernon community since 1936.  Mrs.Stura was a member of the Anita Garibaldi;Belle Vernon Lodge and the Defense Club of Belle Vernon.  Friends will be received from 7 to 9 p.m.Saturday and 2 to 4 and 7 to 9 p.m.Sunday at the Leonard J.Parzynski Funeral Home;626 Broad Ave.;Belle Vernon;where the Belle Vernon Knights of Columbus Council 3026 will hold services Saturday at 7:30 p.m.  On Monday;Oct.21;a Prayer service will be held at the funeral home at 9:30 a.m.;followed by a Mass of Christian Burial at 10 a.m.at St.Sebastian Catholic Church of Belle Vernon.  Interment will follow in the Belle Vernon Cemetery Chapel.  The Leonard J.Parzynski Funeral Home is in charge of arrangements.