24/7 Wall St.

The stock market is up Wednesday, with the Dow Jones Industrial Average up 0.61%, the Nasdaq up 0.54% and the S&P 500 up 0.46%. Today’s winners include a medical diagnostic developer who reported good results on a study and a medical device maker who reported higher than expected sales estimates for 2013. The sole loser is a for-profit educator continuing to struggle with declining enrollment.

These are Wednesday’s market winners and loser.

Biggest Winners

Shares of Rosetta Genomics, Ltd. (NASDAQ: ROSG) are up 22.05% to $5.62 on trading volume of 2.8 million shares. The medical diagnostics developer’s shares rose following positive news of a tumor study. The 52-week high is $23.43.

Shares of NuVasive, Inc. (NASDAQ: NUVA) are up 10.91% to $17.48 on trading volume of 1.5 million shares. The company, which makes devices to treat spinal problems, announced it would likely achieve sales of about $655 million in 2013, better than the $638.2 million analysts polled by Reuters had expected. The 52-week high is $25.99.

Biggest Loser

Shares of Apollo Group Inc. (NASDAQ: APOL) are down 8.98% to $19.06 on trading volume of 4.2 million shares. The for-profit educator, which is the parent company of the University of Phoenix, announced that enrollment in its programs declined by 14% and new students signing up for classes fell 15% for the quarter, the third straight quarter of declines. The 52-week high is $58.29.

Follow Samuel on Twitter: SWeigley