Dynavax Technologies ( DVAX) felt a pinch following disappointing second-quarter results released after the close of trading Thursday. The company's loss widened to 50 cents a share from 35 cents a share a year ago. Analysts were expecting a loss of 29 cents a share. Revenue for the quarter was $500,000, compared with $1 million last year. Analysts were expecting Dynavax's top line to reach $1.67 million. Shares fell 6% to $3.93. NuVasive's ( NUVA) shares rose 11.3% to $17.66 on better-than-expected quarterly results and a boost to its full-year guidance. While the maker of surgical devices reported a GAAP loss of $18.5 million, or 56 cents a share, the company lost $3.7 million, or 11 cents a share, excluding charges. Analysts were expecting a loss of 24 cents a share. Quarterly revenue also beat estimates, reaching $22.7 million vs. the $21.4 million analysts were expecting. The company raised its full-year revenue guidance to between $90 million and $92 million. In April, NuVasive said it expected annual revenue between $87 million and $91 million. Medical Staffing Network ( MRN) shares were bolstered following a report that its second-quarter earnings reached 4 cents a share compared with 1 cent a share last year. Analysts were expecting earnings to be flat. Shares of the health care staffing company were up 5.6% to $5.88. Neurologic drug developer Renovis ( RNVS) saw its shares jump 16.8% to $12.37 a day after it said its quarterly loss narrowed and revenue improved. The company reported second-quarter revenue of $3.7 million, up from $700,000 a year ago, and a loss of $5.8 million, or 20 cents a share, compared with a loss of $10 million, or 41 cents a share, a year ago. For the year, the company boosted its revenue guidance to between $10.0 million and $10.5 million, up from a previously guided range of $8.8 million to $9.2 million. Other movers included Novadel Pharma ( NVD), up 2.6% to $1.18, and Titan Pharmaceuticals ( TTP), trading 8.1% higher to $1.86. Cigna ( CI) was down 3.8% to $91.78, and Apria Healthcare Group ( AHG) lost 4.1% to $18.