[1] UNIV PERUGIA,GEN HOSP,INST GERONTOL,I-06100 PERUGIA,ITALY
[2] UNIV PERUGIA,GEN HOSP,INST PATHOL,I-06100 PERUGIA,ITALY
[3] UNIV PERUGIA,GEN HOSP,DEPT BIOCHEM,I-06100 PERUGIA,ITALY
[4] UNIV PERUGIA,GEN HOSP,DEPT BIOMETR BIOSTAT,I-06100 PERUGIA,ITALY
[5] UNIV PERUGIA,GEN HOSP,BIOCHEM MICROBIOL ANAL SERV,I-06100 PERUGIA,ITALY