The Dow Jones industrial average rebounded sharply Friday, after losing more than 45 points Thursday. The Dow rose 37.93 to end the day at 4,741.75. The New York Stock Exchange composite index was also up 1.07 to 308.63. On the Big Board, advancers led decliners 1,146 to 1,090, with 798 unchanged. The technology-heavy Nasdaq composite index was up 5.63 to 1,023.20. At the American Stock Exchange, the market value index fell 1.57 to 514.40. In London, gold closed at $382.55, off $0.40.