position
1969 - 1971 Instructor in Medicine and Research Associate in Gastroenterology, Hospital of University of Pennsylvania, Philadelphia, PA, USA  
1972 -1977 Associate Professor of Medicine, University of Ankara School of Medicine, Ankara, Turkey  
1977 - 1982 Professor of Medicine (tenured), Gastroenterology Department, University of Ankara School of Medicine, Ankara, Turkey  
1980 - 1982 Visiting Professor of Medicine, Gastroenterology Section, Department of Medicine, Tulane University School of Medicine, New Orleans, LA  
1982 - 1991 Professor of Medicine (tenured), Gastroenterology Section, Department of Medicine, Tulane University School of Medicine, New Orleans, LA  
1984 - 1991 Adjunct Professor of Physiology, Department of Physiology, Tulane University School of Medicine, New Orleans, LA  
1986 - 1991 Chief of Gastroenterology Section, Tulane University School of Medicine, New Orleans, LA  
1989 - 1990 Interim Chairman, Department of Medicine, Tulane University School of Medicine, New Orleans, LA  
1991 - 2000 Professor of Medicine (tenured) and Associate Chief, Gastroenterology Division, Department of Medicine, Baylor College of Medicine, Houston, TX  
1991 - 2000 Chief of Gastroenterology Section The Methodist Hospital/Baylor College of Medicine Houston, TX  
2000-Present Clinical Professor of Medicine, Department of Medicine, Baylor College of Medicine, Houston, TX
2005-Present Clinical Professor of Medicine, Weill Medical College of Cornell University
2005-Present Founder & co-owner of Texas International Endoscopy Center
2007-Present Co-founder, co-owner & Chief Medical Officer of "Priviledged Care Houston, LLC"