The relationship between cagA positivity and serum gastrin and TNF- alpha levels in patients with chronic active gastritis and duodenal ulcer associated with Helicobacter pylori - YILMAZ, Mustafa; AYDIN, Ahmet; UNGAN, Mehmet; GÜNŞAR, Fulya; ERSÖZ, Galip; ÖZÜTEMİZ, Ömer and AKARCA, Ulus and ÇAVUŞOĞLU, Hanefi (Turkish Journal of Gastroenterology, 1999)