By Caroline Valetkevitch NEW YORK, June 27 (Reuters) - Small- and mid-capitalization stocks rose on Wednesday, led by gains in energy companies following a jump in oil prices. The S&P MidCap 400 index ended up 0.88 percent while the S&P SmallCap 600 index were up 1.33 percent. In comparison, the benchmark S&P 500 gained 0.9 percent. The mid-cap index, however, is down 9.5 percent since its March 19 intraday high, and the small-cap index is down 8.5 percent since its March 27 intraday high. Among top percentage gainers were Patriot Coal, up 17.8 percent at $1.26, and QuickSilver Resources, up 16.3 percent at $5.06. Shares of Arch Coal gained 8.6 percent to $6.03. Shares of Gulfport Energy were up 10.8 percent at $18.34. Oil and natural gas futures rose, with U.S. August crude gaining 85 cents, or 1.07 percent, to settle at $80.21 a barrel. Among other top stock advancers, shares of Arena Pharmaceuticals jumped 28.7 percent to $11.39 after U.S. health regulators approved its pill to treat obesity, making it the first weight-loss drug in 13 years.