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Background/Aims: In the natural history of gastric cancer, non-invasive neoplasia (NiN) precedes invasive carcinoma. A histological classification of gastric NiN has recently been proposed by a World Health Organisation international panel of experts. Genetic instability is known to be among the molecular pathways involved in gastric oncogenesis. In this retrospective cross sectional study, microsatellite instability (MSI) was analysed in a consecutive series of NiN and NiN related histological alterations from a northern Italian region at high risk for gastric cancer. Patients/Methods: Fifty five consecutive cases (indefinite for NiN, 29 cases; low grade NiN, 17 cases; high grade NiN, nine cases) were analysed by radioactive polymerase chain reaction and electrophoresis for microsatellite alterations at six loci (BAT25, BAT26, D2S123, D5S346, D17S250, and D3S1317). MSI was defined according to the Bethesda criteria distinguishing: (1) no instability in the analysed loci; (2) low frequency MSI (MSI-L); and (3) high frequency MSI (MSI-H). lmmunohistochemical expression of MLH1 and MSH2 proteins was also analysed in all cases. Results: Overall, MSI was found in 11 of 55 cases (indefinite for NiN, five of 29 (MSI-L, four; MSI-H, one); low grade NiN, three of 17 (MSI-L, one; MSI-H, two); high grade NiN, three of nine (MSl-L, one; MSl-H, two). Conclusions: In an Italian high risk area for gastric cancer, MSI is part of the spectrum of genetic alterations in gastric non-invasive neoplasia. In European populations at high risk of gastric cancer, DNA repair system alterations are thought to be among the early molecular events in gastric carcinogenesis. [ABSTRACT FROM AUTHOR]

AIMS--To identify distinguishing and general histological features related to the use of non-steroidal anti-inflammatory drugs (NSAID). METHODS--Slides from gastric antral biopsies of 50 patients with osteoarthritis taking NSAID were compared with slides from antral biopsies of 50 control cases matched for age, sex, and race. Semithin sections stained with toluidine blue were used. RESULTS--Chronic gastritis was seen in 76% of the patients taking NSAID and in 58% of the control cases; active inflammation was detected in 10% of the NSAID treated patients and in 24% of the control cases, and it appeared closely related with Helicobacter pylori infection. Some histological features common to all slides of patients taking NSAID were recognised. These consisted of focal erosions of the gastric epithelium and macroerosions, and they seemed to represent successive steps of a process of "desquamation". CONCLUSIONS--Some distinguishing morphological aspects appeared prominent; it is suggested that these may be related to the pathogenesis of NSAID linked peptic ulceration. On the other hand, epithelial damage due to NSAID appears very different from that due to Helicobacter pylori, another important factor involved in the aetiopathogenesis of peptic disease. [ABSTRACT FROM PUBLISHER]

Ultrastructural morphology of the bacterial bodies was studied in 40 Helicobacter pylori positive cases. Two bacterial patterns were identified, which were associated with different modes of contact with the epithelial cells and possibly with different stages of the natural history of the infection. [ABSTRACT FROM PUBLISHER]