SAHLEN AND ASSOCIATES <SALNU> COMPLETES PURCHASE Sahlen and Associates Inc said it has completed the purchase of Gleason Securities Service Inc of New York and Gleason Plant Security Inc of Connecticut. Sahlen said the deal's terms were not disclosed, but added that the acquired companies had combined annual revenues of over 18 mln dlrs. Sahlen, a private invetigation company, said the Gleason companies provide security guard services to corporations in the tri-state area.