Shares of Repligen ( RGEN) were among the best-performing health-related stocks Friday, rising 6% after the company said it expanded its development agreement with the Stanley Medical Research Institute.

As part of the expanded agreement, Repligen will receive about $1 million in additional funding for a Phase II clinical trial of uridine for treating bipolar depression. "We are very pleased to receive the additional support for our uridine program from The Stanley Medical Research Institute, a world leader in the support and development of new drugs for bipolar disorder and schizophrenia," the company said. "The study has the potential to provide proof of concept for uridine in bipolar depression." Repligen will begin the Phase II study upon Food and Drug Administration approval. Shares recently traded up 19 cents to $3.50.

Quidel ( QDEL) rose 6% after the company said its diagnostic test for influenza performed well in a recent study. The company's QuickVue influenza A+B test showed 96% sensitivity and 97% specificity in detecting "type A" influenza, the company said. The study was completed in Australia during flu season from July through September 2005. "The high clinical accuracy of the QuickVue test to detect type A influenza is especially significant in that the type A influenza viruses are most commonly associated with epidemics and pandemics, such as the one which occurred in 1918," the company said.

In separate studies during the 2004-05 flu season in Hong Kong and Japan with in vitro cultured virus, the company's test was able to detect the H5N1 virus, which causes avian flu, Quidel said. "Now that we know the QuickVue Influenza A+B test can detect H5N1 and other avian influenzas that have been cultured in vitro, we are committed to working with public health officials worldwide to determine how we can contribute to enhancing both human and avian influenza surveillance," the company said. Shares recently gained 61 cents to $10.81.

Tenet Healthcare ( THC) fell 6% after the company's chief financial officer resigned after just seven months on the job. Robert Shapard is leaving the hospital operator to take a job with his former employer, TXU ( TXU). When Shapard leaves in early November, Timothy Pullen, Tenet's chief accounting officer, will take over as interim CFO until a permanent replacement is found. Shares were trading down 54 cents to $9.24.

Ventana Medical Systems ( VMSI) rose 1% after the company posted third-quarter results that topped forecasts. The company earned $3.6 million, or 10 cents a share, on sales of $50.7 million. On an adjusted basis, which excludes certain items, Ventana earned $6.8 million, or 19 cents a share. Analysts polled by Thomson First Call had forecast earnings of 17 cents a share and sales of $47.8 million. A year ago, the company reported adjusted earnings of $5.5 million, or 15 cents a share, on sales of $39.3 million. Shares were trading up 51 cents to $36.21.

Shares of Manor Care ( HCR) rose 2% after the nursing-home operator posted better-than-expected third-quarter earnings. Manor Care earned $50.2 million, or 60 cents a share, on sales of $840.3 million. Excluding a one-time gain, the company would have earned 52 cents a share. Analysts projected earnings of 50 cents a share and sales of $843.9 million. A year ago, the company earned $39.1 million, or 45 cents a share, on sales of $806.8 million. Shares were up 74 cents to $37.99.

Other health care volume movers included Pfizer ( PFE), down 68 cents to $21.22; Novavax ( NVAX), up 40 cents to $3.59; Amgen ( AMGN), up 25 cents to $73.85; Johnson & Johnson ( JNJ), down 8 cents to $64.09; Merck ( MRK), down 31 cents to $26.61; Bristol-Myers Squibb ( BMY), down 13 cents to $21.54; BioCryst Pharmaceuticals ( BCRX), up 22 cents to $14.37; Guidant ( GDT), down 30 cents to $63.38; Gilead Sciences ( GILD), down 1 cent to $45.20; and Schering-Plough ( SGP), down 23 cents to $21.07.

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