NY -- Standard&Poor's CreditWire 6/19/98 –- Standard&Poor's today assigned its double-'A' rating to North Carolina Medical Care Commission's $386 million revenue bonds series 1998 dated July 1, 1998, issued for Duke University Hospital. The bonds are scheduled to sell July 28, 1998. At the same time, Standard&Poor's affirmed its ratings on Duke University's and North Carolina Medical Care Commission's $242 million in outstanding debt, also issued for the hospital (see list below). The rating reflects high expectations that the rapid changes and acquisitions occurring at Duke will ultimately benefit bondholders despite an interim weakening of financial position. Duke University's board of trustees recently voted to separately incorporate the hospital and Duke University Hospital will