US STOCKS-Wall St ends up on earnings, rebound in high-growth shares
* Merck quarterly profit tops estimate but revenue misses
* Twitter to report earnings after market close
* More U.S. companies beating earnings expectations
* Indexes up: Dow 0.5 pct, S&P 0.5 pct, Nasdaq 0.7 pct (Updates to close)
By Caroline Valetkevitch
NEW YORK, April 29 (Reuters) - U.S. stocks rose on Tuesday, boosted by upbeat results from companies including Merck & Co and a rebound in Facebook and other high-growth shares.
Merck & Co 's shares climbed 3.6 percent to $58.72, giving the S&P 500 its biggest lift, after it reported stronger-than-expected earnings.
Further deal activity on the healthcare front also lifted the market, with Britain's Reckitt Benckiser Group Plc confirming talks to buy Merck's consumer health business, the latest asset up for grabs in a wave of recent pharmaceutical deals.
"Investors are viewing (that activity) as a signal for positive conditions in which businesses are willing and able to offer substantial sums of cash and/or stocks," said Mark Luschini, chief investment strategist at Janney Montgomery Scott in Philadelphia. Continuación...