Tweeter Home Entertainment ( TWTR) surged more than 32% Thursday on a broad restructuring plan. The electronics retailer said it will close 49 stores that were expected to "contribute negatively" in the near term, as well as two regional facilities, resulting in a 20% reduction of its workforce and a complete pullout from five states. The plan will result in a charge of $50 million to $60 million. The Canton, Mass., company also intends to use its popular "consumer electronics playground" format in all of its remaining stores and any new locations, with plans to revamp any stores that aren't already suited for it. Shares were rising 43 cents to $1.77. Chattem ( CHTT) jumped after waning fiscal first-quarter profits beat Wall Street estimates. The Chattanooga, Tenn., drugmaker earned $13.7 million, or 71 cents a share, compared with 75 cents last year; but analysts were seeking 61 cents, according to Thomson Financial. The company also raised its expected full-year earnings range by a nickel, now forecasting between $2.71 to $2.96 a share (including stock options). Analysts are calling for $2.76 a share. Chattem stock was gaining $4.51, or 8.5%, to $57.87. Arrowhead Research ( ARWR) climbed after its majority-owned unit Unidym agreed to merge with Carbon Nanotechnologies. As a result of the merger, Unidym "will hold the leading portfolio of intellectual property on carbon nanotubes" -- the products in which Carbon specializes. Arrowhead will pay $5.4 million in preferred shares as part of the deal. The transaction should close in early April. Pasadena, Calif.-based Arrowhead was up 57 cents, or 14.9%, to $4.39.