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Simon Bar-Meir

Publications and source records attributed to Simon Bar-Meir.

23 records · Page 2Linked to original sources
PubMed2003

Immunohistochemical analyses of colon cancer in I1307K APC mutation carriers compared with noncarriers.

The I1307K APC germline mutation is associated with an increased risk to colorectal cancer (CRC). Whether and to what extent the somatic features and the molecular pathways of cancer development in mutation carriers differ from colorectal cancer in noncarriers remains unknown. To gain insight into this issue, 52 Israeli patients with CRC, 24 of whom were I1307K APC mutation carriers, were analyzed. The expression pattern of genes known to be involved in the pathogenesis of sporadic CRC was assessed immunohistochemically: E-cadherin, beta-catenin, deleted in colon cancer (DCC), and p53. In addition, tumors were genotyped for somatic activating mutations in Ki-ras oncogene. Mutation carriers and noncarriers were comparable in age at diagnosis (64.3 +/- 10.1 years for carriers and 60.8 +/- 14.1 years for noncarriers), tumor location in the colon, and disease stages. Tumors of I1307K mutation carriers displayed positive p53 immunostaining and loss of beta-catenin, E-cadherin, and DCC expression more often compared with noncarriers, although none of these differences reached statistical significance. Mutation frequencies in the Ki-ras gene were similar in both groups. In conclusion, the molecular pathways in CRC in I1307K APC mutation carriers are seemingly similar to those of sporadic cases, but a larger study is clearly needed.

Case-Control Studies↗
PubMed2003

The optimal dose of 5-aminosalicylic acid in active ulcerative colitis: a dose-finding study with newly developed mesalamine.

BACKGROUND AND AIMS: 5-Aminosalicylate is the gold standard for inducing remission in patients with mildly to moderately active ulcerative colitis. The optimal dose is as yet not defined. Despite some recent developments, the ideal formulation for 5-aminosalicylic acid is still awaited. A new pellet preparation was designed combining slow and delayed release properties. Aims of the study were to find the optimal dose and to test efficacy and safety of a new 5-aminosalicylic acid formulation. METHODS: Three hundred twenty-one patients were included in a double-blind multicenter trial. Inclusion criteria were active ulcerative colitis (Clinical Activity Index [CAI] and Endoscopic Index [EI] according to Rachmilewitz, CAI 6-12; EI >/=4). Three different doses of 5-aminosalicylic acid (0.5 g 3 times a day, 1.0 g 3 times a day, and 1.5 g 3 times a day) were studied for 8 weeks. RESULTS: Clinical remission rate (CAI </=4) was highest in the 1.0 g 3 times a day group (66 %), 50% in the 0.5 g 3 times a day group, and 55% in the 1.5 g 3 times a day group. Hierarchical testing showed no significance, indicating a lack of dose response across the 3 mesalamine doses. In addition, times to first clinical response were similar: 26.5 days (1.0 g 3 times a day), 27.5 days (0.5 g 3 times a day), and 21.5 days (1.5 g 3 times a day). Endoscopic improvement was better with 1.0 g mesalamine 3 times a day than with 0.5 g 3 times a day, but overall endoscopic and histologic improvement was not different between treatment groups. Baseline activity, duration, and localization of ulcerative colitis did have some influence on the therapeutic activity, but there was no significant interaction with the dose of the study drug. Safety, with special focus on kidney function, was excellent in all 3 groups. CONCLUSIONS: There is no significant dose response between mesalamine 1.5 g/day, 3.0 g/day, and 4.5 g/day. The optimal dose to induce remission of ulcerative colitis is 0.5 g 5-aminosalicylic acid 3 times a day. Patients failing with this dose may benefit from an increase of the dose up to 1.0 g 3 times a day, but should also be considered for alternative treatment. A newly developed pellet formulation of 5-aminosalicylic acid has promising efficacy and excellent safety.

Adult↗
PubMed2003

Clinical and demographic characterization of Jewish Crohn's disease patients in Israel.

BACKGROUND: Crohn's disease (CD) is a chronic transmural inflammatory disease of unknown etiology. Genetic background may influence the nature of disease. The Jewish population in Israel is composed of Ashkenazi and Sephardic Jews, who differ in their genetic background. Previous studies have reported that the prevalence of CD in Sephardic Jews is lower than in Ashkenazi Jews; however, no information is available regarding disease characteristics in these patient populations. GOALS: To assess the demographic and clinical characteristics of CD in Israeli Jewish patients. STUDY: We studied 189 CD patients who were observed in our department. Demographic and clinical data were collected and analyzed. RESULTS: Forty-eight percent of the patients had ileum-only disease. Fistulizing disease was more frequently seen in ileocolonic than in ileal ( p= 0.04) or colonic ( p= 0.01) disease, whereas strictures occurred more often in ileal than in colonic disease (22% and 3%, respectively, p= 0.007). No association was found between current smoking and disease severity. Sephardic patients more frequently had extraintestinal disease than did Ashkenazi patients (35% vs. 17%, respectively, = 0.019). CONCLUSION: Jewish Israeli patients show a predilection for ileum-only disease. Disease severity appears not to be influenced by smoking. These differences in disease behavior may be related to genetic factors.

Adolescent↗
PubMed2002

A defined human gastrin sequence stimulates the growth of Helicobacter pylori.

This study describes the interaction between gastrin and Helicobacter pylori. Human gastrin amino acids 4-17 were found to be the minimal growth-stimulating sequence. Gastrin from other mammals did not stimulate bacterial growth. When human serum was used to stimulate bacterial growth in brucella broth, gastrin was shown to be a necessary and sufficient growth-stimulating factor. Competition for the gastrin effect by pentagastrin and cholecystokinin (CCK-8) resulted in inhibition of bacterial growth. This effect was mediated by the four C-terminal amino acids which are shared by gastrin, CCK-8 and pentagastrin. In conclusion, the interaction between gastrin and H. pylori was shown to be specific, essential, and dependent on a defined gastrin sequence.

Amino Acid Sequence↗