Exhibit  23.01


                 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


As independent public accountants, we hereby consent to the incorporation of our
reports dated  February 27, 1998 included in this Form 10-K,  into the Company's
previously  filed  Registration  Statements  on Form S-3,  File  Nos.  33-79794,
33-90734,  33-65333,  333-01595,  333-5185,  333-17433 and 333-34705 and on Form
S-8, File nos. 33-89144, 333-15369 and 333-40873.




                                                /s/ARTHUR ANDERSEN LLP


Washington, D.C.,
April 20, 1998