• Affymetrix Inc., of Santa Clara, Calif., has entered into an agreement to sell $275 million worth of 3.5 percent unsecured senior convertible notes due in 2038. It granted the underwriter, JF Morgan Securities, an over-allotment option to purchase up to $41.25 million aggregate principal amount of additional notes on the same terms and conditions.

• HistoRx Inc., of New Haven, Conn., has secured $6 million in a Series B private equity financing round. Current investor Brook Venture Partners led the round. Other participants included another Series A investor, Navigator Technology Ventures, as well as three new investors: The Roche Venture Fund, Commons Capital and Maven Capital. HistoRx will use the funds to advance its portfolio of proprietary tissue-based diagnostic products developed from its AQUA biomarker analysis platform.

• MicroIslet Inc., of San Diego, has entered into an agreement to sell common stock to a private trust for gross proceeds of $1 million. The company has agreed to sell an aggregate of approximately 2.35 million shares and to issue to the investor warrants to purchase an aggregate of approximately 1.3 million shares. The warrants have an exercise price of $0.60 per share and are exercisable for five years beginning in one year. The company expects to use the proceeds of the financing for working capital purposes.

• Pipex Pharmaceuticals Inc., of Ann Arbor, Mich., has received approximately $7.3 million in gross proceeds through the exercise of warrants to purchase the company's common stock. The company said it now should have enough funds to last into 2008 when it hopes to obtain FDA approval for its anticopper drug candidate Coprexa and/or its serum-free copper diagnostic device, FreeBound. A new drug application is expected to be filed for Coprexa yet this year, and a pre-IDE package was submitted for FreeBound in October.