Tokyo stocks opened higher Wednesday on buying after overnight gains on Wall Street and the Bank of Japan’s decision the previous day to keep intact its ultraloose monetary policy. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average rose 409.24 points, or 1.23 percent, from Tuesday to 33,628.63. The broader Topix index was up 20.47 points, or 0.88 percent, at 2,354.28. On the top-tier Prime Market, gainers were led by machinery, mining and consumer credit issues. At 9 a.m., the U.S. dollar fetched 143.91-94 yen compared with 143.79-89 yen in New York and 144.16-18 yen in Tok…