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The localization of granular cell tumor to the rectum is rare. We describe a case characterized by areas with spindle cell pattern, pleomorphic cells with acidophilic granular cytoplasm, nuclear variations and absence of mitoses. Diagnosis has been confirmed by immunohistochemical study. After 22-month follow-up the patient does not show evidence of recurrence or metastases.

The authors' previous observation that many of the monoclonal antibodies against Helicobacter pylori cross-react with the cells of the human gastric mucosa prompted them to investigate the possibility that gastric self-antigens cross-reacting with H. pylori could be involved in the immune response against this organism. It was found that three antibodies against H. pylori, CB-4, CB-10, and CB-14, that cross-react with the human gastric mucosa also intensely cross-reacted with murine gastric epithelial cells. A strong reaction against autologous mucosa was also evident in the sera of mice immunized with H. pylori but not with other bacteria. A serological study performed in a group of 82 patients undergoing gastroscopy showed that the presence of seropositivity against H. pylori was strongly correlated with the presence of autoantibodies against human antral gastric mucosa. This activity was neutralized after absorption of the sera with H. pylori but not with other gram-negative bacteria. The antibodies in the mouse and in the human did not react with other segments of the gastrointestinal tract or with most of the other organs. Mice bearing hybridomas secreting a cross-reacting antibody (CB-4) had histopathologic abnormalities in their stomachs. These lesions were absent in the stomachs of mice bearing hybridomas secreting a non-cross-reacting antibody (CB-26). It was concluded that H. pylori infection can stimulate antibodies cross-reacting with gastric autoantigens and that this immunologic mechanism may represent a pathogenic link between H. pylori and gastritis.

The effects of lactose, L-fucose, and D-glucose on differentiation and glycosylation of MCF-7 cells from human mammary cancer were tested. For determination of glycosylation, six lectins with various binding specificity were used. The cells cultivated in the medium with D-glucose alone showed the best growth. The cells growing in the medium with L-fucose displayed, at the beginning growth acceleration which was followed by a rapid onset of necrotization. A decreased content of D-glucose usually resulted in an accelerated differentiation and a more pronounced secretory activity of cells. Expression of binding sites for lectins PNA and WGA was higher in cultures with elevated proliferation and reduced differentiation, DBA bound better the cells cultivated in the presence of lactose, lectins Con A and RCA60 in the presence of L-fucose. The UEA-1 showed only minimal affinity for MCF-7 cells. The majority of lectins showed an increased binding ability to secretory vacuoles and vesicles in the presence of L-fucose. The results obtained support the hypothesis that cell differentiation is associated with various stages of glycosylation and that the type of sugar in the medium can significantly affect glycosylation and differentiation processes.