US STOCKS-Dow, S&P 500 fall after Morgan Stanley results; oil slips
* Exxon, Chevron biggest drags on S&P 500, Dow
* Weight Watchers soars after Oprah takes stake
* China Q3 GDP data better than expected
* Dow down 0.24 pct, S&P down 0.25 pct, Nasdaq up 0.13 pct (Adds details, changes comment, updates prices)
By Abhiram Nandakumar
Oct 19 (Reuters) - The Dow and S&P 500 indexes were lower on Monday after a slide in oil prices and a swathe of weak quarterly results led by Morgan Stanley but a recovery in healthcare and biotech stocks pushed the Nasdaq Composite up.
The energy index fell 1.7 percent as Brent crude prices slid 2.5 percent to $49.22 per barrel on worries about demand concerns out of China and progress on the nuclear deal with Iran.
Exxon's 1.4 percent fall to $81.30 weighed the most on the S&P 500 while Chevron fell 1.7 percent to $89.71 to be the biggest drag on the Dow Jones industrial average .
Morgan Stanley's shares fell as much as 6.9 percent to $31.60 after the bank's profit fell for the second straight quarter, capping mostly downbeat quarterly results from major U.S. banks. The stock recorded its biggest results-day decline since 2009. Continuación...