Tokyo stocks opened higher Tuesday on buying spurred by strong gains on Wall Street overnight, including the tech-heavy Nasdaq that finished at a fresh record high. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average rose 348.31 points, or 0.91 percent, from Monday to 38,450.75. The broader Topix index was up 20.63 points, or 0.76 percent, at 2,720.64. On the top-tier Prime Market, gainers were led by oil and coal product, transportation equipment and insurance issues. At 9 a.m., the U.S. dollar fetched 157.68-71 yen compared with 157.67-77 yen in New York and 157.55-56 yen …