Stock index futures pointed to a mixed open on Wall Street on Tuesday, with futures for the S&P 500 down 0.02 percent, Dow Jones futures up 0.11 percent and Nasdaq 100 futures down 0.7 percent at 3:45 a.m. EST.

* Apple shares will be in the spotlight after the company said Chief Executive Steve Jobs was taking medical leave for the third time since 2004, reviving fears over the long-term future of the iPhone- and iPad-maker and sending the company's stock traded in Frankfurt tumbling more than 8 percent.

* On the earnings front, investors were bracing for results from a number of companies including Apple, Citigroup and IBM .

* Goldman Sachs said it will limit its private placement of shares of social networking site Facebook to investors outside the United States, citing intense media coverage.

* Brewing giant SABMiller beat forecasts with a 3 percent rise in beer volumes in the last three months boosted by growth in Africa and Asia offsetting a fall in Colombia, hit by the heaviest rain for 50 years.

* European planemaker Airbus celebrated a surprise win in the annual orders race against Boeing with the 10,000th plane sale in its 40-year history, part of a $5 billion order from Virgin America. Separately, Boeing Co resumed certification tests of its 787 Dreamliner on Monday for the first time since an in-flight electrical fire in November knocked those trials off schedule.

* GlaxoSmithKline will record a legal charge of $3.4 billion for the fourth quarter, effectively wiping out its profit, as it settles further claims related to Avandia and sales practices.

* South African retailer Massmart's shareholders have accepted a takeover by U.S. group Wal-Mart , setting up the world's largest retailer for a potential battle with local unions.

* European stocks were up 0.7 percent in morning trade, led by mining shares after Rio Tinto's output figures pleased investors and as metal prices climbed.

* The S&P 500 ended a seventh straight week of gains with a banks-led rally amid healthy volume after encouraging financial results from JPMorgan.

* The Dow Jones industrial average <.DJI> added 55.48 points, or 0.47 percent, to 11,787.38. The Standard & Poor's 500 <.SPX> rose 9.48 points, or 0.74 percent, to 1,293.24. The Nasdaq Composite <.IXIC> gained 20.01 points, or 0.73 percent, to 2,755.30.

(Reporting by Blaise Robinson; Editing by Jon Loades-Carter)