) -- Bio-tech company

Strategic Diagnostics

( SDIX) was the biggest gainer among small-caps in Wednesday afternoon trading. Shares were skyrocketing 42% to $2.63 after it said that the U.S. Food and Drug Administration approved its RapidCheck Salmonella test for poultry use.

The RapidCheck test helps egg producers identify Salmonella in the environment before it contaminates the egg, reducing the chance of egg recalls.

Earlier in the day, stocks jumped nearly 70% to $3.13, its highest level in over two years.

Jewelry retailer



was up 32% to $5.32 after it reported same-store sales rose 7.5% in November and December, after dropping 12% during the same period a year-ago. Other jewelry retailers have also reported strong sales in the holiday season. According to a

Wall Street Journal

report, the company may consider selling its Piercing Pagoda chain to New York private-equity firm Apollo Global Management.

Video game provider

Majesco Entertainment


saw its stock jump 25% to $1.15. The company announced that it has sold more than 500,000 units of its "Zumba Fitness" interactive video game for Wii, Kinect and PlayStation Move motion controller to retailers nationwide. The video game has become one of Majesco's fastest-selling titles.

Helios & Matheson North America

( HMNA),

ZBB Energy



Radio One


were among the other stocks that were topping the winners list.

Leapfrog Enterprises


, maker of educational toys, said it expects current-year results to fall short of expectations. Net income per share is expected to be between 3 cents and 6 cents, significantly lower than analyst estimates of 28 cents. Demand for toys slowed down after a strong start in the holiday season. The company reports fourth-quarter results on Feb.10.

KV Pharmaceuticals

( KV-A) plunged 23% to $1.76 after it said that it was "evaluating its liquidity outlook," in light of an expected delay in the drug regulator's approval of Gestiva, a drug used in the treatment of preterm birth in women.

Shares of

Constar International

(CNST) - Get Report

were sinking 14% to 68 cents after the company filed its second bankruptcy in two years. The company said it had reached an agreement with 75% of its senior debt holders for a restructuring agreement that included reducing its debt of $220 million by $125 million to $150 million. The company emerged out of bankruptcy only in May 2009.


(THOR) - Get Report


PAB Bankshares



Stealth Gas

(GASS) - Get Report

were other stocks dominating the losers list in afternoon trading.

-- Written by Shanthi Bharatwaj in New York

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Shanthi Bharatwaj


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Disclosure: TheStreet's editorial policy prohibits staff editors and reporters from holding positions in any individual stocks.