The proposed St. Thomas Ambulatory Surgical Center is the topic for a noon membership luncheon of the St. Thomas-St. John Chamber of Commerce at Wyndham Sugar Bay Resort on St. Thomas. Guest speakers will be Drs. Jeffrey Chase, Cathering Kean, Sonia Taylor-Griffiths and Adam Shapiro and attorney David Bornn. The cost is $22; for reservations, call 776-0100.