ABSTRACT
La infección por Helicobacter pylori está asociada con gastritis, úlcera gastroduodenal, linfoma tipo Maltoma, y es considerado un importante factor de riesgo para el desarrollo de cáncer gástrico. El objetivo de este estudio fue caracterizar los genotipos vacA de cepas de H. pylori provenientes de biopsias gástricas de una población venezolana. Se evaluaron 128 pacientes con indicación de endoscopia, por enfermedad de las vías digestivas superiores. Se obtuvieron biopsias gástricas de cada uno de ellos para la amplificación de glm y tipificación de las formas alélicas de vacA, empleando la reacción en cadena de la polimerasa. Los resultados demostraron que 82 (64%) de las muestras fueron positivas para la amplificación de glm. De estos, 51 (62%) de las cepas tenían el genotipo vacA, forma alélica S1 (17 s1a, 29 s1b, 5 s1a+s1b, 10 fueron no tipificables) y 21 (26%) tenían el subtipo S2. El análisis de la región media de vacA reveló que 42 (51%) fueron vac A m1, 26 (32%) m2 y 14 (17%) no tipificaron para m1 o m2. Los resultados de la presente investigación demostraron una alta frecuencia de infección por H pylori genotipo vac A variante alèlica s1/ m1.
Helicobacter pylori infection is associated with gastritis, gastroduodenal ulcer, and Maltoma type lymphoma, and is also considered an important risk factor for the development of gastric cancer. The purpose of this study was to characterize vacA genotypes of H. pylori strains from gastric biopsies from a Venezuelan population. One hundred and twenty eight patients who required endoscopy due to disease of the upper digestive system were evaluated. A gastric biopsy was taken from each of them for glm amplification and typing of the allelic vacA forms, using the polymerase chain reaction assay. Results showed that 82 (64%) of the samples were positive for glm amplification. Of these, 51 (62%) of the strains had the vacA genotype, S1 allelic form (17 sla, 29 slb, 5 sla+slb, 10 were not typable) and 21 (26%) had the S2 subtype. The analysis of the vacA mid region revealed that 42 (51%) were vacA m1, 26 (32%) m2, and 14 did not type for m1 or m2. The results of this investigation showed a high frequency of H. pylori vacA genotype infections, s1/m1 allelic variants.
ABSTRACT
The role of toxins in the pathogenesis of bloody diarrhea caused by Shigella and Salmonella isolated from children with bloody diarhea was studied for production of toxins active on cells in culture and in rat intestinal loops. Humman epithelial cellls from colon carcinoma (HT-29), Chinese hamster ovary cells (CHO) and kidney fibroblast from rhesus monkey (Vero) were used to detect cytotoxins. On HT-29 almost 50 percent of the Shigella and about 20 percent of the Salmonella strain caused rounding of cells; on CHO over 50 percent Salmonella and 20 percent of Shigella strains caused elongation of cells, some strains caused also rounding of these cells whereas on Vero over 60 percent of Salmonella and 40 percent of Shigella strains caused rounding of cells. Cytotoxicity on Vero and CHO cells was strongly inhibited with cholera toxin antiserum, whereas that on HT-29 was inhibited with C. difficile toxin B antiserum. Cytotonic activity on CHO cells and rounding on Vero cells seem to be suitable models to detect toxins cross-reacting with cholera toxin. Both species, Shigella and Salmonella, produce cytotoxins and enterotoxins which could play a role in intestinal disease