Javier Torres-López

Effect of the flavonoid quercetin on inflammation and lipid peroxidation induced by Helicobacter pylori in gastric mucosa of guinea pig

BackgroundHelicobacter pylori infection induces an inflammatory response in the gastric mucosa. Activation of polymorphonuclear leukocytes can produce oxidative damage to gastric tissue through intermediary radicals of oxygen and nitrogen. Vegetable extracts containing polyphenols of the flavonoid family have antibacterial activity, and the flavonoid quercetin possesses anti-H. pylori activity in vitro. The aim of this study was to analyze the effect of oral administration of pure quercetin on inflammation and lipid peroxidation induced by H. pylori in the gastric mucosa of the guinea pig.MethodsSixty days after oral infection with H. pylori guinea pigs received 200 mg/kg of quercetin daily by mouth for 15 days. The infiltration index of inflammatory cells and bacterial density in both the pyloric antrum and corpus were histologically determined by myeloperoxidase histochemistry, hematoxylin-eosin, and modified Giemsa stains. The lipid hydroperoxide content was assessed by the orange xylenol spectrophotometric method.ResultsQuercetin significantly reduced the infiltration index of mononuclear cell and bacterial colonization in the pyloric antrum and corpus. In the antrum of infected quercetin-treated animals, a significant diminution of neutrophil leukocyte infiltration was observed compared with the infected nonquercetin-treated animals. In the antrum, the lipid hydroperoxide concentration was significantly decreased in infected animals treated with quercetin, whereas in the corpus no significant differences were observed.ConclusionsOur results indicate that in vivo oral quercetin administration decreases H. pylori infection in the gastric mucosa and reduces both the inflammatory response and lipid peroxidation.

In vivo expression of helicobacter pylori virulence genes in patients with gastritis, ulcer, and gastric cancer

ABSTRACT The best-studied Helicobacter pylori virulence factor associated with development of peptic ulcer disease or gastric cancer (GC) rather than asymptomatic nonatrophic gastritis (NAG) is the cag pathogenicity island (cagPAI), which encodes a type IV secretion system (T4SS) that injects the CagA oncoprotein into host epithelial cells. Here we used real-time reverse transcription-PCR (RT-PCR) to measure the in vivo expression of genes on the cagPAI and of other virulence genes in patients with NAG, duodenal ulcer (DU), or GC. In vivo expression of H. pylori virulence genes was greater overall in gastric biopsy specimens of patients with GC than in those of patients with NAG or DU. However, since in vitro expression of cagA was not greater in H. pylori strains from patients with GC than in those from patients with NAG or DU, increased expression in GC in vivo is likely a result of environmental conditions in the gastric mucosa, though it may in turn cause more severe pathology. Increased expression of virulence genes in GC may represent a stress response to elevated pH or other environmental conditions in the stomach of patients with GC, which may be less hospitable to H. pylori colonization than the acidic environment in patients with NAG or DU.

Exposición a Estreptococo del grupo B en mujeres mexicanas en edad reproductiva

Objective. To assess the prevalence of IgG antibodies against Group B streptococci (GBS) among women of reproductive age in Mexico. Material and Methods. Serum specimens were drawn from 15 to 40 year-old women, representative of all regions and socioeconomic levels of the country. The sample was randomly selected from Banco Nacional de Sueros (National Sera Bank); serum samples were collected during a national seroepidemiologic survey conducted in 1987-1988. The assays for standardization and for evaluation of seroprevalence were carried out at the Hospital de Pediatria del Centro Medico Nacional Siglo XXI (Childrens Hospital) Instituto Mexicano del Seguro Social (IMSS) (Mexican Institute of Social Security) from January to November 1995. IgG antibodies against group B antigen were studied with an enzyme-linked immunosorbent assay (ELISA) developed in our lab. Group B antigen was produced and purified from the reference strain GBS 110. Results. A total of 2669 serum samples were studied; 2405 were positive to anti-group B antigen IgG antibodies, for a seroprevalence of 90.2%. No differences in prevalence were found among the different age groups or among the different states of the country. Conclusions. The high seroprevalence of antibodies against GBS suggests that young women in Mexico are commonly exposed to GBS infection.

Secretion Antigens of Mycobacterium tuberculosis : A Comparison Between a Reference Strain and Seven Wild Isolates

BACKGROUND This study was carried out with the aim of detecting possible differences between proteins secreted by fresh wild isolates of Mycobacterium tuberculosis and from a reference strain of this microorganism, H37Rv TMCC 102. MATERIALS AND METHODS This reference strain of M. tuberculosis has been in our laboratory for over 10 years, where it has been maintained by serial subcultures in PBY and Lowenstein-Jensen media. Patterns of protein secretion and recognition by sera derived from both tuberculosis patients and normal individuals were analyzed by electrophoresis and Western blotting. RESULTS No major qualitative differences were observed among the several strains studied with respect to protein patterns or recognition of these proteins by test sera. Normal sera were found to react with almost all antigens recognized by tuberculosis sera, but with less intensity. However, a small protein of 14.5 kDa, secreted by both the wild and reference strains of M. tuberculosis, was recognized by 32 of the 40 tuberculous patient sera tested (80%), and was not recognized by any of the 40 serum samples derived from healthy individuals. CONCLUSIONS This small protein seems to be a potentially important antigen for the serological diagnosis of tuberculosis and/or for use in the follow-up of patients who received treatment.