1555 Third Ave., 2nd floor, New York, N.Y. 10128owner at Allen M Kaufman MD PLLC Past: Chief, Nephrology and other positions at Beth Israel Medical Center, Chief, Dialysis and... I am a physician specializing in nephrology and hypertension. The former Chief of Nephrology at Beth Israel Medical Canter, I am now in private practice in... I am a physician specializing in nephrology and hypertension. The former Chief of Nephrology at Beth Israel Medical Canter, I am now in private practice in Manhattan.