Nikkei opened higher Monday as market sentiment was lifted by reports that the International Monetary Fund is planning a bailout for Italy. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average rose 117.79 points, or 1.44 percent, from Friday to 8,277. 80. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was up 8.88 points, or 1.26 percent, at 715. 48.