[1] SAPPORO MED COLL,DEPT MICROBIOL,SAPPORO,HOKKAIDO 060,JAPAN
[2] HOKKAIDO UNIV,SCH MED,DEPT OPHTALMOL,SAPPORO,HOKKAIDO 060,JAPAN
[3] HIGASHI NIPPON GAKUEN UNIV,SCH DENT,DEPT PREVENT DENT,ISHIKARI,HOKKAIDO 06102,JAPAN
[4] YOKOHAMA CITY UNIV,SCH MED,DEPT OPHTHALMOL,YOKOHAMA,KANAGAWA 236,JAPAN
[5] HOKKAIDO UNIV,FAC SCI,DEPT CHEM,SAPPORO,HOKKAIDO 060,JAPAN