Gold prices shifted slightly lower on the Comex division of the New York Mercantile Exchange Wednesday, dropping 60 cents to settle at $1,572.20 per troy ounce. Silver shed 20 cents and closed at $26.90 per troy ounce. Commodities have held steady, almost at a crouch, through the week, with trading subdued in advance of a European Union summit scheduled for Thursday and Friday. There are big ideas on the agenda, including rescue efforts for Spain, Cyprus and for European banks in general. Traders are reluctant to make strong moves in advance of a possible policy announcement. On Wednesday, the dollar index was flat, rising 0.19 percent to 82.55 on the Intentional Exchange, regaining about what was lost in the prior trading session. The euro fell to $1.247 from Tuesday\'s $1.2496. Against the yen, the dollar rose to 79.70 yen from 79.51 yen. The British pound fell to $1.5569 from $1.5643. The dollar rose to 1.0249 Canadian dollars from 1.0238 Canadian.