Companies like Procter & Gamble (PG), McDonald's (MCD) and FedEx (FDX) have been pushing investment in China and other developing nations as growth in Europe, the U.S. and other developed nations became stagnant. But with global economic troubles and growth in China slowing, investing in volatile developing markets has hurt even large companies' bottom lines. P&G on Wednesday lowered its sales and profit guidance on unfavorable foreign exchange