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Background & Objective: The pathogenesis of appendicitis remains poorly understood. However there is increasing evidence of involvement of the enteric nervous system in immune regulation and in inflammatory responses.This study was setup to characterize the status of the enteric nervous system and mast cells in acute appendicitis with normal and non inflamed appendix with clinical symptoms Materials & Methods: In this descriptive study, staining in surgically resected appendixes from 15 patients with histologically proven acute appendicitis (Histologically appendicitis, HA), 15 histologically normal appendix (Histologically normal, HN) from patients with a clinical diagnosis of appendicitis and normal histology,and15 normal appendixes from patients undergoing elective abdominal surgery were studied in Shaid Mostafa Khomeyni medical center, Iran during 2000-01. S100-Positive schwann cells and synaptophisin-positive nerve fibers were evaluated with immunohistochemical staining and mast cells were evaluated with histochemical staining with Toloiden –blue.The number of nerve fibres, schwann cells and mast cells in each tissue compartment was measured quantitively with light microscope in 20 microscopic high power fields. Then the mean number of cells was calculated in each field (×400). Results: Increased numbers of fibers and schwann cells widely distributed in the Muscularis and submucosa were seen in the all HA appendixes. Increased numbers of mast cells distributed in submucosa were seen in the all HA appendixes. A significantly increased number of individually stained nerve fibers, schwann cells and mast cells were present in HA appendixes compared with control appendixes (P<0.05). Conclusion: In this study showed that significant increase in neural components and mast cells in acute appendicitis indicates the interaction between the nervous system and mast cells in pathogenesis of acute appendicitis.

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Background & Objective: The breast cancer is the most common malignancy in women. MDM2 expression is determined in some carcinomas, sarcomas, leukemias,and breast cancer. The purpose of this study was to determine the expression of MDM2 gene in primary breast cancer and it’s relationship with grade, stage and axillary lymph node involvement. Materials & Methods: the study was the cross-sectional one, that was performed on 75 samples of patients with breast cancer admitted in Mostafa Khomeini hospital Tehran, Iran (2000-05). After preparing the samples, a tissue section from each samples was obtained. One of the tumoral sections and one of the lymph node sections were stained by H&E. We determined the type of the tumor, the number of lymph nodes, the stage and the grade of the tumor. We studied MDM2 with polyclonal antibody by IHC. Results: The meanSD of patients were 5412.5 years old. 69.3% of patients had lymphoid involvement. 32% of samples were positive for MDM2. 58.7% of samples were in stage II and the most of patients (42.7%) were in grade III. In this study, there was not any relationship between MDM2 and tumor grade, but there was a relationship between stage of tumor and lymph node involvement with MDM2 gene (P<0.05). Conclusion: This study showed that MDM2 gene is a prognostic factor in breast cancer.