Updated from 3:47 p.m. EST

Shares of

ViaCell

( VIAC) were among the best-performing health-related stocks Friday, rising 24.1% on the biotech firm's first day of trading as a public company.

The stem cell research company sold 7.5 million shares of stock at $7 apiece, raising more than $52 million. The company plans to use proceeds from the offering to fund clinical trials, debt repayment and general corporate purposes. The IPO, which priced at the low end of the company's proposed range of $7 to $9 a share, was led by CS First Boston and UBS Investment Bank, which acted as co-managers on the deal. Shares of ViaCell traded up $1.69 to $8.69.

NBTY

( NTY) rose 3.5% after the nutritional supplements company posted a first-quarter profit that was ahead of expectations. The company earned $30 million, or 43 cents a share, on sales of $420.3 million. Analysts were expecting earnings of 33 cents a share on sales of $411.4 million. A year ago, NBTY earned $24 million, or 34 cents a share, on sales of $385.1 million. Shares traded up 87 cents to $26.11.

Shares of

Amylin Pharmaceuticals

( AMLN) rose 1.8% after the company said it plans to sell 8 million shares of stock for $22 apiece, raising more than $160 million in proceeds. Morgan Stanley led the underwriting syndicate. Shares traded up 40 cents to $22.66.

Other health care movers included

Pfizer

(PFE) - Get Report

, down 50 cents to $24.48;

Aastrom Biosciences

(ASTM)

, up 10 cents to $4;

Bristol-Myers Squibb

(BMY) - Get Report

, down 27 cents to $24.17;

StemCells

(STEM)

, down 26 cents to $5.92;

Merck

(MRK) - Get Report

, down 37 cents to $30.36;

Amgen

(AMGN) - Get Report

, up 1 cent to $62.57; and

Schering-Plough

( SGP), down 7 cents to $19.99.