New H. pylori infection and complete healing of infected mucosa may occur in adult life, but this is rare. Duodenal ulcer disease is associated with persistent H. pylori infection and absence of corpus atrophy. The appearance of parietal cell antibodies leads to progression of corpus atrophy and disappearance of H. pylori.
H pylori associated chronic gastritis was the associated disease in 75% of the patients with gastric cancer occurring equally often in both IGCA and DGCA groups. About 25% of cases seem to have a normal stomach or severe corpus limited atrophy, neither of which showed evidence of concomitant H pylori infection.
Tumor necrosis factor‐alpha (TNF) is a multifunctional cytokine which is cytotoxic for some tumor cells and transformed cells. The molecular mechanisms which render transformed and tumor cells sensitive to the cytotoxic action of TNF are unclear. We show here that an increased expression of the c‐Myc oncoprotein strongly increases cellular sensitivity to TNF cytotoxicity. In Rat1A fibroblasts, which are resistant to TNF, the addition of TNF with a concomitant activation of a hormone‐inducible c‐Myc‐estrogen receptor chimera (MycER) resulted in apoptotic cell death. Similarly, c‐Myc overexpression enhanced the sensitivity of NIH3T3 fibroblasts to TNF‐induced death. The c‐Myc and TNF‐induced apoptosis was inhibited by ectopic expression of the Bcl2 oncoprotein and by the free oxygen radical scavenging enzyme Mn superoxide dismutase. Furthermore, in highly TNF‐sensitive fibrosarcoma cells, antisense c‐myc oligodeoxynucleotides caused a specific inhibition of TNF cytotoxicity. Our results suggest that the deregulation of c‐Myc, which is common in human tumors and tumor cell lines is one reason why these cells are TNF sensitive.
Summary Comparative genomic hybridization (CGH) was used to detect copy number changes of DNA sequences in the Ewing family of tumours (ET). We analysed 20 samples from 17 patients. Fifteen tumours (75%) showed copy number changes. Gains of DNA sequences were much more frequent than losses, the majority of the gains affecting whole chromosomes or whole chromosome arms. Recurrent findings included copy number increases for chromosomes 8 (seven out of 20 samples; 35%), 1q (five samples; 25%) and 12 (five samples; 25%). The minimal common regions of these gains were the whole chromosomes 8 and 12, and 1q21-22. High-level amplifications affected 8q13-24, 1q and 1q21-22, each once. Southern blot analysis of the specimen with high-level amplification at 1q21-22 showed an amplification of FLG and SPRR3, both mapped to this region. All cases with a gain of chromosome 12 simultaneously showed a gain of chromosome 8. Comparison of CGH findings with cytogenetic analysis of the same tumours and previous cytogenetic reports of ET showed, in general, concordant results. In conclusion, our findings confirm that secondary changes, which may have prognostic significance in ET, are trisomy 8, trisomy 12 and a gain of DNA sequences in 1 q.
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