[Allergy, pollen and the environment]. / Alergia, pólenes y medio ambiente.

Allergic respiratory diseases such asthma and allergic rhinitis are a health problem throughout the world. In Mexico City, pollens are an important cause of allergic respiratory disease. Both, the geographic location- and the vegetation surrounding this City favor the distribution of pollens leading to respiratory disease in susceptible patients. Aerobiological studies have shown that during the mild dry winter there is a large amount of pollens in the environment with tree pollens being the most abundant of all. The most frequent tree pollens found in Mexico City include Fraxinus, Cupressaseae, Alnus, Liquidambar, Callistemon, Pinus, and Casuarina. In contrast, grass- and weed pollens predominate during the summer (rainy season) including Compositae, Cheno-Am, Ambrosia and Gramineae. An additional health problem in Mexico City is the air pollution that exerts a direct effect on individuals. This in turn increases pollen allergenicity by disrupting them leading to the release of their particles which then penetrate the human airways causing disease. Thus, the polluted environment along with global warming which is also known to increase pollen quantities by inducing longer pollen seasons may represent a health risk to Mexico City inhabitants.

Alergia, pólenes y medio ambiente / Allergy, pollen and the environment

Las enfermedades respiratorias como el asma y la rinitis, de origen predominantemente alérgico, constituyen un problema de salud pública para México, ya que son causas importantes de morbilidad hospitalaria y de ingresos a urgencias pediátricas. Los pólenes son transportados por el viento y se impactan en las vías aéreas causando enfermedad respiratoria alérgica en personas susceptibles. Estudios aerobiológicos en México muestran que en la temporada de secas se encuentra una mayor abundancia y diversidad de pólenes, siendo los árboles la fuente principal. Los tipos polínicos de árboles que sobresalen por su abundancia son Pinus, Fraxinus, Cupressaseae, Alnus, Liquidambar, Callistemon y Casuarina. Interesantemente, el polen de malezas y pastos alcanza su pico máximo de producción durante la temporada de lluvias. Los taxa de malezas y pastos que han sido encontrados de manera más numerosa son Compositae, Cheno-Am, Ambrosia y Gramineae, correspondiendo los primeros tres a malezas y el último a pastos. En la ciudad de México, la contaminación es un factor que exacerba la alergenicidad de los pólenes, ya que los contaminantes causan un efecto directo sobre el propio grano al liberar sus antígenos. En el mundo, el calentamiento global ha favorecido el desarrollo de alergias respiratorias debido a que las etapas de floración son más prolongadas. Todo esto en conjunto representa una amenaza para la salud de los pacientes alérgicos.

Allergic respiratory diseases such asthma and allergic rhinitis are a health problem throughout the world. In Mexico City, pollens are an important cause of allergic respiratory disease. Both, the geographic location- and the vegetation surrounding this City favor the distribution of pollens leading to respiratory disease in susceptible patients. Aerobiological studies have shown that during the mild dry winter there is a large amount of pollens in the environment with tree pollens being the most abundant of all. The most frequent tree pollens found in Mexico City include Fraxinus, Cupressaseae, Alnus, Liquidambar, Callistemon, Pinus, and Casuarina. In contrast, grass- and weed pollens predominate during the summer (rainy season) including Compositae, Cheno-Am, Ambrosia and Gramineae. An additional health problem in Mexico City is the air pollution that exerts a direct effect on individuals. This in turn increases pollen allergenicity by disrupting them leading to the release of their particles which then penetrate the human airways causing disease. Thus, the polluted environment along with global warming which is also known to increase pollen quantities by inducing longer pollen seasons may represent a health risk to Mexico City inhabitants.

Topographic expression of MUC5AC and MUC6 in the gastric mucosa infected by Helicobacter pylori and in associated diseases.

We investigated the topographic expression of MUC5AC and MUC6 in relationship with gastric diseases. The immunoexpression of MUC5AC and MUC6 was evaluated in 75 adults presenting Helicobacter pylori gastritis (n = 22; 11 cagA positive), duodenal ulcer (DU, n = 11), gastric ulcer (GU, n = 9), gastric carcinoma (GC, n = 20), and normal mucosa (H. pylori negative, n = 13). Five gastric areas (antral and corporeal lesser and greater curvatures and incisura) were studied. H. pylori was detected by carbolfuchsin, urease, and culture; cagA was determined by PCR. All patients with DU (eight with GU and 13 with GC) were H. pylori-positive. In H. pylori gastritis, MUC5AC expression was higher in the antrum than in the corpus; no difference was observed with respect to cagA status. MUC5AC expression was higher in the antrum of gastritis than in DU, and it was lower in the incisura among GU patients compared to DU. MUC6 expression was higher in the antrum of H. pylori gastritis compared to DU and to uninfected patients. No difference was observed in the topographic pattern of expression of MUC5AC and MUC6 among GC cases. The topographic over- and under-expression of mucins in H. pylori-associated gastritis and peptic disease suggest a role for these mucins in the pathogenesis of H. pylori infection and associated diseases.

Lewis antigen expression in gastric mucosa of children: relationship with Helicobacter pylori infection.

OBJECTIVE: Lewis epithelial antigen expression has a role in Helicobacter pylori adherence, presumably mainly in cagA-positive strains. The authors investigated whether Lewis antigen expression in children's gastric mucosa was associated with H. pylori infection, cagA status, patient age, or presence of duodenal ulcer (DU). METHODS: The expression of Lewis A (Le(a)), B (Le(b)), X (Le(x)), and Y (Le(y)) was detected by immunohistochemistry in the antral and oxyntic mucosae of 70 children. Children were divided in four age groups (<4 years; 4-8 years; 9-12 years; and 13-18 years). RESULTS: Forty-seven of the 70 children had H. pylori and 17 had DU. The cagA status was determined by polymerase chain reaction in 34 patients. Le(a) and Le(b) were expressed in 64% and 44% of the patients, respectively; Le(x) and Le(y) were expressed in the glands in all of the patients and in the superficial epithelium. Le(b) expression was more common among patients without H. pylori (15/23, 65%) than in those with H. pylori (16/47, 34%) (P = 0.03). In noninfected patients, Le(b) and superficial Le(y) expression were associated with increased age. Le(b) expression was more common in patients with chronic gastritis than in those with DU. Le(x) superficial expression was significantly associated with DU in patients with H. pylori. CONCLUSION: In children, the expression of Le(b) and Le(y) in the superficial gastric epithelium depends on age. Other receptors, such as Le(x), may have a role in H. pylori colonization, especially in patients with DU. Studies assessing the expression of Lewis antigens in children may contribute to an understanding of the mechanisms of acquisition of H. pylori infection.

MUC1 polymorphism confers increased risk for intestinal metaplasia in a Colombian population with chronic gastritis.

Gastric cancer (GC) stands as the second most common cause of cancer death for males worldwide, and intestinal metaplasia (IM) is a lesion that precedes GC development. In previous works it was shown that polymorphisms of MUC1 gene are associated with increased risk for GC and IM. The aim of the present study was to evaluate MUC1 gene polymorphism in patients with chronic gastritis from Colombia. A Portuguese population of patients with chronic gastritis was used for comparative purposes. A total of 67 Colombian cases and 52 Portuguese cases were analysed by restriction analysis and Southern blotting. MUC1 allele frequencies were significantly different between the two populations, with an overall prevalence of smaller alleles in Colombian samples. Colombian cases showed a lower prevalence of individuals homozygous for small MUC1 mucins in cases without IM (62.5%) when compared with cases with IM (86.0%). The same trend, although not statistically significant, is observed in the Portuguese population. In conclusion, our study shows that Colombian patients with chronic gastritis have a significantly higher prevalence of small MUC1 alleles than the Portuguese population. Our study also shows that small MUC1 genotypes are associated with increased risk for IM development in Colombian patients.