[p53 expression in the gastric mucosa of patients infected with Helicobacter pylori]. / p53 expresado en la mucosa gástrica de pacientes infectados por Helicobacter pylori.

BACKGROUND: Helicobacter pylori (Hp) is recognized as a type 1 carcinogen for gastric cancer associated with pre-neoplastic lesions (atrophy and intestinal metaplasia [IM]). Its relation with p53, which intervenes in the cell cycle, has had contradictory results. AIMS: To analyze p53 expression in gastric mucosa and its relation with Hp infection. METHODS: A 3-month prospective, observational, cross-sectional study was conducted. Patients that had no evidence of acute or clinically significant gastric pathology had biopsies taken according to the Sydney system at the Hospital Juárez de México and the histopathologic studies were done at the Hospital Español de México. RESULTS: Hp prevalence was 32.7% in 104 patients. There were no cases of atrophy or dysplasia. A total of 91% of the infected patients were positive for p53. Of the non-infected patients, 14% were positive for p53 and 60% of them had IM. Of the IM patients, 75% presented with positive p53. Of the patients without IM, 31 presented with positive p53, and Hp was positive in 85% of them. There was association between Hp and p53 and between p53 and IM (P<.0001 and P<.0006, respectively). CONCLUSIONS: Significant association was shown between Hp and p53 expression, even in patients with pre-neoplastic lesions that no longer presented with Hp. Given that the identification of pre-neoplastic lesions is important for the prevention of cancer, immunohistochemistry could benefit routine biopsy carried out during endoscopy for the detection of Hp, by identifying patients with expression of the important oncogene regulator, p53.

[Endoscopic inanimate biological simulators for training in endoscopic mucosal dissection]. / Entrenamiento en la disección endoscópica de la submucosa "mediante el uso de simuladores biológicos inanimados.

BACKGROUND: Simulators have been used as a training method; they allow training, skill development, standardization of techniques and the performance of a greater number of risk-free procedures. Endoscopic submucosal dissection (ESD) is the standard treatment for early gastric cancer since it allows en bloc resection of larger lesions however requires longer procedure time and has more complications than endoscopic mucosal resection. OBJECTIVE: To evaluate the use of biological inanimate simulators in endoscopic training for the development of skills required for ESD. METHODS: Experimental design using a biological inanimate simulator to evaluate the development of endoscopic skills. Five trained endoscopists with knowledge of the ESD technique, but without previous experience were selected. Technical success, complication rate and procedure time were evaluated. Each participant performed a self-evaluation. RESULTS: 18 lesions of 10-20 mm in diameter were dissected, with a mean area of 2.64 ± 2 cm2 and a mean procedure time of 21.08 ± 14.01 minutes (5.48 - 48.61). Self-evaluation and instructor's evaluation showed a strong positive correlation. There was no correlation between lesion size and procedure time. There was one perforation (5.8%), which was successfully managed with one endoclip. Complications such as bleeding could not be assed. CONCLUSIONS: The use of inanimate biological simulators allows training in complex endoscopic procedures such as ESD with a wide safety margin. Lesion size did not correlate with procedure time. It is necessary to increase the number of procedures to improve the learning curve. This simulator does not allow evaluation of complications other than perforations.