Yaffe Ruden and Associates is one of the most premiere medical offices in New York City, specializing in Internal Medicine, Endoscopy, and Colonoscopy. Office Hours: Monday-Friday 8am - 7pm Saturday 8:30am - 12:30pm 65th Street Office: 212-879-4700 Fax: 212-249-7580 84th Street Office: 212-717-9470.