Health stocks sputtered Tuesday, with a few exceptions including buyout target

ViaCell

( VIAC).

The biotech company bounded $2.41, or 50.5%, to $7.18, after announcing Monday that it will be acquired by

PerkinElmer

(PKI) - Get Report

in a transaction worth about $300 million. Waltham, Mass.-based PerkinElmer dropped 95 cents, or 3.2%, to $28.91.

After aggressive pushing by shareholders,

PDL BioPharma

(PDLI) - Get Report

finally caved and said its board will actively seek offers to sell the company. Also, CEO Mark McDade, who had previously resigned effective Jan. 1, is now stepping down immediately. The board's Patrick Gage will be taking over in the interim. The board elected Karen Dawes to serve as chair, replacing Gage.

Last week, Highland Capital Management, which owns a 4.7% stake in PDL BioPharma, followed in fellow shareholder Third Point's footsteps and called for PDL's board to sell the company and Gage and McDade to resign immediately. Investors seemed enthusiastic with the progress, sending the stock up $1.87, or 8.8%, to $23.24. The stock is a component of the Amex Biopharmaceutical Index, which was down 2.20 points, or 0.3%, to 828.89.

Also,

AngioDynamics

(ANGO) - Get Report

rose 59 cents, or 3%, to $20.40. The company reaffirmed its fiscal 2008 outlook after Monday's close and said net income was up 25% year-over-year to $2.38 million in the first quarter of 2008. Sales climbed 85% compared to the year-ago quarter to $3.8 million.

Elsewhere,

TST Recommends

Isis Pharmaceuticals

(ISIS)

received approval from antitrust regulators for a previously announced collaboration with

Johnson & Johnson

(JNJ) - Get Report

unit Ortho-McNeil for joint discovery of new treatments for metabolic diseases. Separately, Isis received a $5 million milestone payment from Johnson & Johnson for initiation of a phase I study on ISIS 325568.

Isis edged up 23 cents, or 1.5%, to $15.49, while J&J was down 9 cents, or 0.1%, to $66.05.

In the other direction,

Onyx Pharmaceuticals

(ONXX)

was downgraded by Bear Stearns to peer perform from outperform Tuesday. The analyst has a price target of $45 for Onyx, which receded $1.20, or 2.7%, to $42.71.

"While we expect solid off-label use of Nexavar in HCC

liver cancer into year-end and a strong launch in HCC in 2008, we believe that near-term upside may be limited for new investors," the analyst writes.

Additionally, Credit Suisse analyst Michael Aberman downgraded

Biogen

(BIIB) - Get Report

to underperform from neutral. Shares were trading down $2.28, or 3.4%, to $65.66 after closing at $67.94 Monday.

Aberman said rumors that have driven up the stock's share price are unlikely to be validated. He also said Biogen's management may be unrealistic about sales expectations. Aberman did raise his price target to $59 from $53.