* Nextel Communications of Reston retained former U.S. attorney general Richard L. Thornburgh to defend its proposal asking the Federal Communications Commission to grant it new cellular airwaves. In a letter yesterday to the FCC, Thornburgh rejected as "diversions" claims made by Nextel's rival, Verizon Wireless, and its parent company that the proposal violates laws prohibiting spending federal funds without a congressional appropriation. Under Nextel's proposal, the company would exchange some of its existing airwaves and pay for the relocation of public safety groups to clearer spectrums. The FCC yesterday issued a notice that it would vote on the Nextel proposal at its July 8 meeting.

* American Systems, a Chantilly systems engineering and technology services company, acquired True North Solutions, a Herndon information security firm. Financial terms of the deal were not disclosed. True North, which has 67 employees, will maintain its office in Herndon and continue to operate as an independent subsidiary. True North's chief executive, Bobby Christian, and its president, Michael Volk, will stay with the company. No layoffs are expected as a result of the acquisition. American Systems has about 1,400 employees.

* Guilford Pharmaceuticals said it had priced its offering of 10 million common shares at $4.50 per share and granted the underwriters an option to purchase up to 1.5 million additional shares to cover any over-allotments. The offering is expected to close July 7. Baltimore-based Guilford expects to receive approximately $42 million of net proceeds from the sale and plans to use the money to fund clinical trials and studies for pre-clinical product candidates, as well as for working capital.

* Advancis Pharmaceutical of Germantown acquired the exclusive U.S. rights to manufacture, market and sell the Keflex brand of cephalexin from Eli Lilly and Co. for $11 million. Cephalexin ranks third among outpatient antibiotics prescribed in the United States, according to Advancis. It said that Lilly's net sales of Keflex in 2003 were about $4 million.

* Cogent Communications Group, a Washington high-speed Internet service provider, named Reed Harrison president and chief operating officer. Harrison was most recently senior vice president of network engineering and operations at AT&T.

* CompuDyne, a Hanover information security company, named Maurice Boukelif to the newly created position of chief operating officer. Boukelif was most recently vice president of operations for the electronic security solutions division of Honeywell International.

Compiled from reports by Washington Post staff writers, PR Newswire and Business Wire.