Hot Topic ( HOTT), a mall-based chain that sells pop-culture apparel, plunged 11% in after-hours trading as the company cut its guidance to below Street expectations. The company, based in City of Industry, Calif., now expects to see earnings between 20 cents and 22 cents a share, down from its previously announced forecast of 33 cents to 38 cents a share. Analysts polled by Thomson Financial are seeking earnings of 33 cents a share. The company explained the downturn by citing its dismal holiday-season sales figures: Same-store sales fell 5.1% in December, and total revenue for the month edged down 1% from last year to $131 million. Shares were losing $1.46 to $12.08. AngioDynamics ( ANGO) jumped on impressive earnings for the period ended Dec. 2. The Queensbury, N.Y., medical-devices maker posted income of $2.5 million, or 15 cents a share, compared with $1.7 million, or 13 cents a share, a year ago. Analysts had expected earnings to flat-line with last year. Also, revenue was up 30% to $24.4 million, edging past the $24 million consensus. Shares were gaining $1.23, or 5.6%, to $23.20. Intervoice ( INTV), which sells converged voice-and-data technology, lost $88,000 in the fiscal third quarter, or break-even a share, compared with year-ago profits of $3.6 million, or 9 cents a share. However, the results beat estimates by a nickel, and the Dallas-based company was up 20 cents, or 2.7%, to $7.70.