Dow Jones industrial average fell 7.12 points, closing at 3748.31 . . . N.Y.S.E.'s composite index down 0.55, to 250.89 . . . NASDAQ stock market composite index dropped 3.27, to 719.35 . . . American Stock Exchange rose 1.31, to 433.90 . . . Gold gained $0.90, to $387.10 on the Commodity Exchange in New York . . . The 30-year Treasury bond closed with a yield of 7.46 percent, down from 7.50 late Monday.