Tokyo stocks opened mixed Wednesday as buying of high tech-related shares, tracking overnight rises of their U.S. counterparts, was offset by selling to lock in recent gains. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average rose 61.93 points, or 0.16 percent, from Tuesday to 39,235.08. The broader Topix index was down 5.46 points, or 0.20 percent, at 2,781.91. On the top-tier Prime Market, gainers were led by pharmaceutical and bank issues, while transportation equipment and rubber product issues led decliners. At 9 a.m., the U.S. dollar fetched 159.70-71 yen compared wit…