Clinical consequences of Helicobacter pylori infection in children and its relation with the response of the gastric mucosa to the infection

Helicobacter pylori is usually acquired during childhood and remains in the gastric mucosa for years, often lifelong if untreated. It can be concluded that the gastric mucosa of children actively responds to the presence of H. pylori. Current evidences suggest that whereas H. pylori infection rarely causes peptic ulcers or gastric atrophy in children, it seems to be associated with iron deficiency and iron deficiency anemia; the evidence also suggests the infection may cause growth retardation. In contrast, H. pylori infection has been associated with a reduced risk of asthma and allergy in children and adults; also, epidemiological studies suggest that there is an inverse association between H. pylori infection and risk for esophageal adenocarcinoma. The gastric mucosa of children elicits a significant inflammatory response in the site of infection, with increased expression of toll-like receptors (TLRs) and cytokines, and increased epithelial proliferation. This response may partly be responsible for the required "immune training" needed to protect for the development of esophageal cancer, asthma, allergy or even diabetes later in life. The response may as well be associated with growth retardation, iron deficiency and increased risk for enteric infections. It then seems that our co-evolution with H. pylori has rendered benefits for human health making clear that this relationship is complex and the decision to eradicate the infection should be taken with caution.

Infección, inflamación y cáncer gástrico / Infection, inflammation and gastric cancer

Existe una sólida relación entre la infección persistente, la inflamación crónica y el cáncer. Helicobacter pylori es la principal causa del cáncer gástrico, con 900 000 casos nuevos registrados cada año. Este patógeno estimula a las células del epitelio gástrico para secretar IL-8, un quimioatrayente de leucocitos que infiltra el tejido infectado de manera persistente. También se observan concentraciones elevadas de citocinas inflamatorias que promueven la pérdida de la homeostasis local debido a la alteración de la proliferación y apoptosis celular. No es claro el mecanismo por el cual esta reacción inflamatoria lleva al cáncer, pero los radicales libres de O2 y N2 podrían contribuir de modo directo al daño genómico de la mucosa. El virus de Epstein-Barr es otro microorganismo vinculado con el cáncer gástrico. En esta revisión se describen los mecanismos inflamatorios importantes que intervienen en el desarrollo de la tumoración, tal vez compartidos con otros patógenos, lo cual es de gran relevancia ya que alrededor de 25 por ciento de los cánceres se relaciona con infección.

A strong association between persistent infection, chronic inflammation and cancer has been described. Helicobacter pylori is the main cause of gastric cancer, with 900 000 new cases yearly. Helicobacter colonization triggers the gastric epithelial cells to secret IL-8, a chemoattractant of immune cells, which persistently infiltrate the infected tissue. High levels of inflammatory cytokines are found, leading to loss of local homeostasis due to altered cell proliferation and apoptosis. It is not known how this local inflammatory response leads to cancer but the expression of mutagenic O2 and N2 free radicals might directly contribute to the irreversible mucosal genomic damage. Epstein Barr Virus is another pathogen associated with gastric cancer. We review here our current knowledge of inflammatory mechanisms at the site of infection that could be important to the development of cancer and that could be shared by other pathogens. This is of great importance since around 25 percent of cancers are associated with infection.

Antisecretory activity in a lectin fraction of plasma from patients with acute diarrhea

The present study describes the first attempt to detect antisecretory activity in a lectin fraction of plasma from patients with acute diarrhea. The plasma antisecretory protein (ASP) was purified by affinity chromatography in agarose, and its antisecretory activity in rats subjected to intestinal challenge with cholera toxin. During the first 24 h of the diarrheal episode, antisecretory activity in patients (median 0, range 0 -25 percent) was lower than that seen in the asymptomatic group (median 10, range 0 -30 percent); 3 days leter, when diarrhea ceased in most of the patients, the ASP activity increased significantly (median 30, range 0 -70 percent). However, 5 days later the activity decreased again (median 0, range 0 . 55 percent). No differences in ASP levels were found between cases associated with an enteropathogen and those whwew no pathogen was identified. These findings reveal an inverse relationship between the increase in ASP and the patient's intestinal secretion; suggesting that ASP plays a role in the compensatory mechanisms that occur in diarrhea in humans

Frecuencia de vaginitis por G. vaginalis en pacientes que acuden a consulta a un centro de atención primaria en salud / Frequency of vaginitis produced by G. vaginalis in patients seexing attention in a primary health cara center

Se estudiaron248 mujeres a las que se les diagnosticó vaginitis que acudieron a consulta al "Centro de Estudios en Atención Primaria de la Salud". Se les aplicó un cuestionario confidencial para conocer la relación entre la colonización de Gadnerella vaginalis con algunos factores como la edad, estado civil, embarazo, número de relaciones sexuales por semana, utilización o no de métodos de control de natalidad, nunca embarazadas o con uno o más embarazos, cero abortos o uno o más abortos. De las 248 muestras procesadas, se encontraron positivas a G. vaginalis 93(37.5%) de los casos. G. vaginalis fue el microorganismo aislado más frecuente. No se observó asociación entre la presencia de G. vaginalis y los factores de riesgo seleccionados. Se concluyó que G. vaginalis es un microorganismo con alto grado de colonización, que por su potencial patogénico debe vigilarse

Growth retardation in syrian hamsters associated with prolonged colonization with Clostridium difficile

La administración de una dosis única de clindamicina a hamsters dio lugar a la producción de una cepa de C. difficile de baja producción de toxina. La colonización se hizo constante y evidente después de seis meses de administrar el antibiótico. El tratamiento se asoció a un exagerado crecimiento cecal y retraso en el crecimiento en comparación con los animales no tratados. Se infiere que la exposición prolongada a bajos niveles de la toxina de C. difficile puede determinar disfunción del ciego y desnutrición