Tanox ( TNOX) rocketed 43.9% when the Houston-based company announced it will sell itself to biotech giant Genentech ( DNA). Shares will sell for $20 apiece for a total of $919 million, a 47% premium over Thursday's closing price. Tanox shares were trading up $5.99 to $19.63. Fuel Systems Solutions ( FSYS) surged when the Santa Ana, Calif.-based company swung to a third-quarter profit and boosted its full-year revenue guidance. The company, which makes systems that enable internal-combustion engines to run on clean fuels, posted income of $3.4 million, or 22 cents a share, compared with a loss of $9.2 million, or 64 cents a share, a year ago. Revenue climbed 13% to $55.4 million. Looking ahead, the company raised its full-year revenue guidance to at least $210 million, up from an earlier forecast of $200 million. Analysts were calling for revenue of $203.1 million. Shares were higher by $2.79, or 18.3%, to $18.02. Midwest Air Group ( MEH) gained on news that the regional carrier's passenger traffic jumped to 335.3 million revenue miles in October, up 17.3% from a year ago. The Oak Creek, Wis., company also reported an 8.6-point spike in its load factor, a measure of traffic, to 76.5%. Shares were up 55 cents, or 6.8%, to $8.65. Cambridge Display Technology ( OLED) took a nosedive after it posted widening third-quarter losses. The U.K.-based developer of flat-panel displays reported a loss of $9.6 million, or 45 cents a share, compared with a loss of $8.6 million, or 44 cents a share, a year ago. Revenue plummeted to $925,000 from $6.6 million a year ago. Shares were down $1.57, or 20.7%, to $6.02. Plato Learning ( TUTR) shares fell when the Bloomington, Minn-based company sharply cut its income and revenue guidance for the fourth quarter. The company, a developer of computer-based educational tools, now forecasts a loss of between $2 million and $3 million excluding asset impairment, restructuring and other charges, whereas it had previously expected a range between a profit of $1.5 million and a loss of $2.5 million. Revenue is now expected to be between $22.5 million and $23.5 million as compared with previous guidance of $24 million to $29 million. Plato attributed the bleaker outlook to declining numbers of large orders, deferred transaction closings and poor product release timing. Shares were down 35 cents, or 6.1%, to $5.40. Rio Narcea Gold Mines ( RNO) dropped on third-quarter results that missed Wall Street projections. The Spain-based company posted income of $15.6 million, or 10 cents a share, compared with a loss of $9.1 million, or 6 cents a share, a year ago. Two analysts polled by Thomson First Call were looking for earnings of 16 cents a share. Revenue increased to $59.1 million from $30.1 million a year ago. Shares were trading down 35 cents, or 11.9%, to $2.60.