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Background & Objective: Gastric cancer is the 2nd cause of cancer mortality after lung cancer. Approximately 12% of all cancer death are due to gastric cancer. Tumorgenesis is thought to be a multistep process involving a series of genetic changes in oncogenes and suppressor genes. The most common cancer-related genetic change known in human tumors is P53 mutation, particularly in gastric cancer. This study was done to determine P53 gene mutations in gastric cancer. Materials & Methods: This study was performed on 44 biopsy from patients with gastric cancer during 2002 in 3 hospitals in Tehran. For determination of P53 gene mutations was performed PCR-SSCP methods. Results: The patients group comprised 31 males and 13 females (Average age, 60.8 years Ranging from 34 to 84 years). 36 cases (81.8%) intestinal type, 5 cases (11.4%) were diffuse type and 3 cases no defined. 44 gastric cancers of gastric tissues were screened for the mutations of P53 gene mutations in exons 5-8 using the PCR-SSCP analysis. After polyacrylamide gel electrophoresis, 9 patients (20.5%) showed an apparent electrophoretic mobility shift between the cancer and other normal samples. One mutation in exon 5 (11.1%), 2 were detected in exon 6 (22.2%), 3 were found in exon 7 (33.3%) and 3 were detected in exon 8 (33.3%). The mutation rate was 7 of 36 (21.2%) in intestinal type and 2 of (40%) in diffuse type. No significant correlation between P53 gene mutations and age and genus was found. Conclusion: This investigation showed the rate P53 gene mutation (20.5%) in gastric cancer in our society.

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Background and Objective: Aspartame is a kind of artifical and non-sugar sweetener that is used as a sugar substitute in some foods and beverages. This study was done to determine effect of Aspartam on histomorphometric alterations, kidney function and expression of Bcl2, Bax, Caspase 3, P53 Genes in Mice.
Methods: In this experimental study, 36 adult male NMRI mice were allocated into four groups including control group and three experimental groups. The mice in the control group received 0.3 ml of distilled water by oral gavage for 90 days and the experimental groups received 40, 80 and 160 mg/kg aspartame, respectively orally and daily. One day after treatment, blood and kidney tissue samples were taken to evaluate biochemical, histomorphometric alterations and gene expression.
Results: Renal capsule diameter, glomerulus diameter and height of the epithelial layer of distal and proximal tubules were significantly reduced in treated groups compared to control group with increasing dosage of aspartame (P<0.05). However, the size of the urinary space and the diameter of the lumen of distal and proximal tubules were significantly increased in treated groups in compared to control group (P<0.05). The level of blood nitrogen urea (BUN) and creatinine significantly increased treated groups in compared to the control group with increasing dosage of aspartame (P<0.05). Also, with increasing dosage of aspartame, Bcl2 gene expression significantly reduced in treated groups in compared to the control group (P<0.05) however expression of Bax, Caspase 3 and p53 genes were significantly increased in treated groups compared to the control group (P<0.05).
Conclusion: Aspartame can cause changes in biochemical, histomorphometric indices, expression of Bcl2, Bax, Caspase 3 and P53 genes in mice kidney.