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Dive into the research topics where Simón Peraza is active.

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Featured researches published by Simón Peraza.


International Journal of Cancer | 2010

Comparison of polymerase chain reaction and histopathology for the detection of Helicobacter pylori in gastric biopsies.

Catherine de Martel; Martyn Plummer; Leen-Jan van Doorn; Jorge Vivas; Gladys Lopez; Elsa Carillo; Simón Peraza; Nubia Muñoz; Silvia Franceschi

Using data from a Venezuelan cohort of 1,948 adults, the gastric detection of Helicobacter pylori (H. pylori) by polymerase chain reaction (PCR) of the vacA gene in 1 antral biopsy was compared to the detection of H. pylori by histopathology (hematoxylin–eosin and Giemsa staining) in 5 biopsies (antrum and corpus). Overall, H. pylori was detected in 85% and 95% of the subjects by PCR and histopathology, respectively. When results were analyzed by severity of precancerous lesions, PCR on 1 biopsy detected the bacteria less often than histopathology on 5 biopsies in subjects with normal gastric mucosa and non‐atrophic gastritis. However, in subjects with the most severe lesions (intestinal metaplasia type III and dysplasia), PCR on 1 biopsy detected H. pylori as often as histopathology on 5 biopsies, and significantly more often than histopathology on a single biopsy. In conclusion, these findings confirm that histopathology on 5 biopsies is an accurate tool for H. pylori detection in most subjects, compared to the PCR method on 1 biopsy. Nevertheless, the elevated sensitivity of PCR for detecting the bacteria in advanced precancerous lesions, and the possibility to use PCR to distinguish between cagA‐positive and cagA‐negative strains, makes the PCR technique especially useful in studies of stomach cancer.


Journal of the National Cancer Institute | 2007

Chemoprevention of Precancerous Gastric Lesions With Antioxidant Vitamin Supplementation: A Randomized Trial in a High-Risk Population

Martyn Plummer; Jorge Vivas; Gladys Lopez; Juan Carlos Bravo; Simón Peraza; Elsa Carillo; Elsa Cano; Denis Castro; Olga Andrade; Víctor Sánchez; Rita García; Eva Buiatti; Claude Aebischer; Silvia Franceschi; Walter Oliver; Nubia Muñoz


Cancer Epidemiology, Biomarkers & Prevention | 2004

Environmental Factors in Helicobacter pylori-Related Gastric Precancerous Lesions in Venezuela

Ikuko Kato; Jorge Vivas; Martyn Plummer; Gladys Lopez; Simón Peraza; Dennis Castro; Víctor Sánchez; Elsa Cano; Olga Andrade; Rita García; Silvia Franceschi; Walter Oliver; Nubia Muñoz


Cancer Causes & Control | 1994

Difficulty in eradicatingHelicobacter pylori in a population at high risk for stomach cancer in Venezuela

Eva Buiatti; Nubia Muñoz; Jorge Vivas; Elsa Cano; Simón Peraza; Elsa Carillo; Denis Castro; Víctor Sánchez; Olga Andrade; Maja Benz; Silvia de Sanjosé; Walter Oliver


International Journal of Cancer | 1995

Determinants of plasma pepsinogen levels in a population at high risk for stomach cancer in venezuela

Ikuko Kato; Kazumasa Miki; Nubia Muñoz; Jorge Vivas; Gladys Lopez; Simón Peraza; Elsa Carillo; Denis Castro; Olga Andrade; Víctor Sánchez; Elsa Cano; Hernan Ramirez; Reto Muggli; Maja Benz; Walter Oliver


American Journal of Tropical Medicine and Hygiene | 2002

Short report: socioeconomic and seasonal variations of Helicobacter pylori infection in patients in Venezuela.

Maria Gloria Dominguez-Bello; Bernardo Beker; Moises Guelrud; Jorge Vivas; Simón Peraza; María Pérez; Luis R. Pericchi


Cancer Epidemiology, Biomarkers & Prevention | 2000

Lewis Antigen Alterations in a Population at High Risk of Stomach Cancer

Julio Torrado; Martyn Plummer; Jorge Vivas; Jone Garay; Gladys Lopez; Simón Peraza; Elsa Carillo; Walter Oliver; Nubia Muñoz


European Journal of Cancer Prevention | 1993

Chemoprevention trial of precancerous lesions of the stomach in Venezuela

Nubia Muñoz; Jorge Vivas; Eva Buiatti; Simón Peraza; S de Sanjosé; Elsa Cano; Denis Castro; Víctor Sánchez; Olga Andrade; Maja Benz; Walter Oliver


GEN | 2005

Evolución a largo plazo de la metaplasia intestinal tipo III y la displasia gástrica en una zona de alto riesgo para cáncer gástrico

Olga Silva; Rita Márquez; Denny Castro; Jorge Vivas; Mayela Miranda; Simón Peraza; Gladys Lopez; Patricia Martín


GEN | 1996

Cáncer avanzado que simula cáncer gástrico precoz: presentación de tres casos

Gladys Lopez; Simón Peraza; Denny Castro; F Romero Ferrero; J Contreras Penuela

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Nubia Muñoz

International Agency for Research on Cancer

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