U.S.-Russian Commerce: The American-Russian Business Opportunity Congress will convene Thursday and Friday at the Anaheim Marriott in what is billed as the largest-ever gathering of diplomats and business leaders from the two nations. More than 700 participants will exchange information and ideas on trade and development. The keynote speaker Thursday will be Michael Blumenthal, Treasury secretary under President Jimmy Carter and currently chairman of the U.S.-Russian Investment Fund. Also scheduled to attend are Alexander Bolshakov, the vice premier of Russia; Yuly Vorontsov, ambassador of the Russian Federation to the United States, and E.V. Basin, the federation minister of construction. The meetings move to Anaheim after sessions Monday and Tuesday in Las Vegas. For information on attendance, call the Russian American Enterprise Council at (310) 278-8143 or the Protocol Foundation of Orange County at (714) 834-5654.