Tokyo stocks opened higher Monday on bargain-hunting following sharp losses late last week sparked by fears of escalating conflict in the Middle East. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average rose 435.13 points, or 1.17 percent, from Friday to 37,503.48. The broader Topix index was up 46.58 points, or 1.77 percent, at 2,672.90. On the top-tier Prime Market, gainers were led by electric power and gas, bank and air transportation issues. At 9 a.m., the U.S. dollar fetched 154.61-64 yen compared with 154.57-67 yen in New York and 154.47-49 yen in Tokyo at 5 p.m. Frid…