Tokyo stocks ended slightly higher Monday as a weaker yen against the U.S. dollar helped lift major Japanese automakers, but most of the earlier gains were erased as some investors locked in profits. The 225-issue Nikkei Stock Average ended up 53.12 points, or 0.14 percent, from Friday at 38,700.87. The broader Topix index finished 3.36 points, or 0.12 percent, higher at 2,715.99. On the top-tier Prime Market, the main gainers included transportation equipment, bank and nonferrous metal issues. The dollar was relatively firm in the lower 146 yen level in Tokyo after briefly sliding to the uppe…