[Gastrointestinal stromal tumors: case reports and review of the literature].
The Authors describe four cases of gastrointestinal stromal tumours (GIST) two of them were localized in the stomach, the others in the ileum. GIST are neoplasms of mesenchymal origin which develop inside the wall of the digestive tract. The most frequent site is the stomach, followed by the small bowel; less commonly these tumors can affect the oesophagus, the colon and the rectum. GIST originate from precursors of the interstitial cells of Cajal, which are localized in the gastro-intestinal wall and are involved in the regulation of the peristalsis. The treatment is surgical resection. For advanced disease there is a new interesting treatment based on the imatinib, a tyrosine kinase inhibitor.
A momentum space representation of the Berggren completeness is used in Gamow shell model calculations of the 5-7 He isotopes. A major problem in the newly developed Gamow shell model is the extreme growth of the number of many-body configurations as the number of valence particles increases. This problem is addressed using the Lee-Suzuki similarity transformation method in the construction of an effective two-body interaction. At the convergence the dimensionality is found to be drastically reduced as compared to the full problem. This offers a promising approach to the study of weakly bound nuclei.