The immune response to Hymenolepis nana in mice decreases tumorigenesis induced by 7,12 dimethylbenz-anthracene.

BACKGROUND: Cancer is a high-impact disease throughout the world. A negative correlation has been established between the development of cancer and the Th2 immune response. Infection by helminth parasites is characterized by the induction of a strong and long-lasting Th2 response. The aim of this work was to evaluate the effect of the immune response induced by the infection with the helminth Hymenolepis nana, on the tumorigenesis induced by dimethylbenz-anthracene (DMBA) in mice. METHODOLOGY: Four different groups of 14 female BALB/c mice were formed; Group A, dimethyl sulfoxide (DMSO) (vehicle) was administered cutaneously, Group B infected with H. nana, group C, cutaneously DMBA and finally Group D infected with H. nana and cutaneous DMBA. The tumor load was determined in those animals that developed cancerous lesions. In all groups were determined: serum concentration of IgE, IFNγ, IL-10, IL-5 and malondialdehyde (MDA). The inflammatory infiltrate was analyzed from skin samples and the expression of the main eosinophilic protein and myeloperoxidase was determined. RESULTS: The group previously infected with H. nana had a reduced amount of tumors with smaller size, in comparison to the group that received only DMBA; this reduction was associated with lower levels of IFNγ and IL-10, while levels of IgE, IL-5 and MDA were higher. Further, the number of eosinophils and neutrophils was statistically higher in the animals that were previously infected with the helminth and developed less tumors. CONCLUSION: The immune response induced by H. nana infection is associated with the reduction of tumors probably due to the activity of eosinophils and neutrophils.

Sex difference in counts of α4 and α7 nicotinic acetylcholine receptors in the nasal polyps of adults with or without exposure to tobacco smoke.

OBJECTIVE: To assess counts of α4 and α7 nicotinic acetylcholine receptors in nasal polyps of adults with or without long-term exposure to cigarette tobacco smoke. METHODS: Twenty-two patients with and 22 patients without exposure to cigarette tobacco smoke participated in the study. After endoscopic polypectomy, the fragments of the nasal polyps were analysed by immunohistochemistry. RESULTS: Compared to patients with no exposure, patients with exposure showed higher counts of α4 and α7 nicotinic acetylcholine receptors (t-test, p 0.05). CONCLUSION: Exposure to cigarette tobacco smoke may induce increased counts of α4 and α7 nicotinic acetylcholine receptors in nasal polyps of adults, with lower counts in males than females without exposure to tobacco smoke.

Influence of exposure to tobacco cigarette smoke on the eosinophil count in the nasal mucosa of young patients with perennial allergic rhinitis.

BACKGROUND: To assess the influence of exposure to tobacco cigarette smoke on the eosinophil count and the frequency of apoptosis of eosinophils in the nasal mucosa of teenagers with perennial allergic rhinitis. METHODS: Fifty patients were evaluated (aged 10 to 19 years old): 25 patients with and 25 patients with no recent exposure to tobacco cigarette smoke, by means of The Global Youth Tobacco Survey and cotinine/creatinine ratio. After a clinical evaluation, all the patients replied to a validated questionnaire of the severity of nasal symptoms; then, a nasal sample was processed to identify the eosinophil count and the frequency of apoptosis of eosinophils. RESULTS: Patients with active exposure to tobacco cigarette smoke had higher eosinophil counts than patients with no exposure to the smoke. In the two groups, apoptosis of eosinophils in the nasal mucosa was scarce and no significant correlation was observed between the frequency/severity of the nasal symptoms and the eosinophil count. CONCLUSION: Teenagers with perennial allergic rhinitis and active exposure to tobacco cigarette smoke may show increased eosinophil counts in the nasal mucosa, which might not be related to apoptosis of eosinophils or to the frequency/severity of nasal symptoms.

Effect of 1,25(OH)2D3 on BALB/c mice infected with Leishmania mexicana.

The most active metabolite of vitamin D, 1,25(OH)2D3 is a steroid hormone implicated in a wide range of cell functions such as differentiation, proliferation and apoptosis. Leishmania mexicana causes two kinds of cutaneous leishmaniasis: localized or diffuse. In this work we explored the effect of treatment of 1,25(OH)2D3 on a susceptible leishmaniasis mice model. A significant reduction in the lesion size was found in animals treated with 1,25(OH)2D3. Well preserved tissue and presence of large numbers of eosinophils and fibroblasts was found in the group treated with 1,25(OH)2D3. By contrast, destroyed epidermis was observed with large amount of neutrophils and epithelioid macrophages, on infected groups without 1,25(OH)2D3 treatment. The production of pro-inflammatory cytokines in mice infected and treated with 1,25(OH)2D3 was lower than the animals infected without 1,25(OH)2D3 treatment. Interestingly, there were no differences in the number of parasites in both groups. Finally, the amount of collagen was higher in animals with treatment compare with animals without 1,25(OH)2D3 treatment. In summary, mice treated with 1,25 (OH) 2D3 reflect a healing process without elimination of L. mexicana.

Spectrum of RB1 gene mutations and loss of heterozygosity in Mexican patients with retinoblastoma: identification of six novel mutations.

RB1 mutation detection has greatly improved the clinical management of retinoblastoma and provides critical information to predict the risk of inheriting the disease. We screened for RB1 gene sequence alterations in both peripheral blood and tumor specimens from a total of 48 Mexican retinoblastoma patients using an SSCP-based screening approach followed by sequencing. Overall, 21 (43.8%) cases were bilateral and 27 (56.2%) were unilateral. Interestingly, 51.8% of unilateral patients developed the tumor before age 1 year and 10 of which (71.4%) were diagnosed before the age of 6 months. Thirteen different oncogenic mutations were detected in 14/48 (29.2%) patients, 9 of which were germline (64.3%). Six of these mutations are novel (IVS3-1G>T, 125X, 389X, 610X, 750X and -149G>T). The most frequent types of mutation were frameshift and nonsense (30.8% each). Moreover, 5 intronic variants were identified, two of which are novel (g.41908 C/A and g.161976del6T). Loss of heterozygosity of the RB1 gene as assessed by intron1/BamHI and intron17/XbaI intragenic markers was 50.0% (18 of 36 informative cases), being higher in tumors with known mutations (76.9% vs 34.8%). This low mutation detection rate and the earlier age at diagnosis in unilateral retinoblastoma cases suggest that other RB1 inactivating mechanisms could be present in the retinoblastoma development. In this study, mutation analysis was not helpful to distinguish sporadic and hereditary retinoblastoma, so, other approaches are needed to improve the molecular diagnosis of retinoblastoma and supports further investigations of Mexican retinoblastoma patients.