9:15 a.m. Update: The major indexes remained mixed in pre-market action Thursday, as investors took in a spate of economic data. Dow, S&P 500 and Nasdaq futures all traded in a narrow range. The Labor Department said first-time requests for unemployment insurance rose by 11,000 to a seasonally adjusted 444,000 — higher than the 437,000 figured pegged by economists. The number of people filing continuing claims fell to 4.6 million in the week ended