Updated from 4:34 p.m. EDTStocks in New York eked out gains at the end of yet another back-and-forth session for Wall Street on Thursday. The Dow Jones Industrial Average rose 70.49 points, or 0.9%, to 7957.06, while the S&P 500 added 8.37 points, or 1%, to 851.92. The Nasdaq tacked on 6.09 points, or 0.4%, to 1652.21. American Express ( AXP), the strongest component on the Dow, blew past first-quarter profit expectations after the close, even as its earnings fell from a year earlier. Shares rose nearly 8% in the regular session and continued higher in the post-market.