Differential expression of E-cadherin gene in human neuroepithelial tumors

Cadherins are cell-to-cell adhesion molecules that play an important role in the establishment of adherent-type junctions by mediating calcium-dependent cellular interactions. The CDH1 gene encodes the transmembrane glycoprotein E-cadherin which is important in maintaining homophilic cell-cell adhesion in epithelial tissues. E-cadherin interacts with catenin proteins to maintain tissue architecture. Structural defects or loss of expression of E-cadherin have been reported as a common feature in several human cancer types. This study aimed to evaluate the expression of E-cadherin and their correlation with clinical features in microdissected brain tumor samples from 81 patients, divided into 62 astrocytic tumors grades I to IV and 19 medulloblastomas, and from 5 white matter non-neoplasic brain tissue samples. E-cadherin (CDH1) gene expression was analyzed by quantitative real-time polymerase chain reaction. Mann-Whitney, Kruskal-Wallis, Kaplan-Meir, and log-rank tests were performed for statistical analyses. We observed a decrease in expression among pathological grades of neuroepithelial tumors. Non-neoplasic brain tissue showed a higher expression level of CDH1 gene than did neuroepithelial tumors. Expression of E-cadherin gene was higher in astrocytic than embryonal tumors (P = 0.0168). Low-grade malignancy astrocytomas (grades I-II) showed higher CDH1 expression than did high-grade malignancy astrocytomas (grades III-IV) and medulloblastomas (P < 0.0001). Non-neoplasic brain tissue showed a higher expression level of CDH1 gene than grade I malignancy astrocytomas, considered as benign tumors (P = 0.0473). These results suggest that a decrease in E-cadherin gene expression level in high-grade neuroepithelial tumors may be a hallmark of malignancy in dedifferentiated tumors and that it may be possibly correlated with their progression and dissemination.

Health in early adulthood: the contribution of the 1978/79 Ribeirão Preto birth cohort

The increase in non-communicable chronic diseases of adults is due to demographic changes and changes in the risk factors related to physical activity, smoking habits and nutrition. We describe the methodology for the evaluation of persons at 23/25 years of age of a cohort of individuals born in Ribeirão Preto in 1978/79. We present their socioeconomic characteristics and the profile of some risk factors for chronic diseases. A total of 2063 participants were evaluated by means of blood collection, standardized questionnaires, anthropometric and blood pressure measurements, and methacholine bronchoprovocation tests. The sexes were compared by the chi-square test, with alpha = 0.05. Obesity was similar among men and women (12.8 and 11.1 percent); overweight was almost double in men (30.3 vs 17.7 percent). Weight deficit was higher among women than among men (8.6 and 2.6 percent). Women were more sedentary and consumed less alcohol and tobacco. Dietary fat consumption was similar between sexes, with 63 percent consuming large amounts (30 to 39.9 g/day). Metabolic syndrome was twice more frequent among men than women (10.7 vs 4.8 percent), hypertension was six times more frequent (40.9 vs 6.4 percent); altered triglyceride (16.1 vs 9.8 percent) and LDL proportions (5.4 vs 2.7 percent) were also higher in men, while women had a higher percentage of low HDL (44.7 vs 39.5 percent). Asthma and bronchial hyper-responsiveness were 1.7 and 1.5 times more frequent, respectively, among women. The high prevalence of some risk factors for chronic diseases among young adults supports the need for investments in their prevention.

Comparative biology of two populations of Lutzomyia umbratilis (Diptera: Psychodidae) of Central Amazonia, Brazil, under laboratory conditions

Lutzomyia umbratilis é o principal vetor de leishmaniose tegumentar causada por Leishmania guyanensis no norte da América do Sul. Essa espécie tem sido encontrada naturalmente infectada com Leishmania somente ao leste do Rio Negro e norte do Rio Amazonas. Porém, populaçäes dessa espécie de flebotomíneo também estão presentes em áreas do sul do sistema fluvial do Rio Amazonas, o qual pode atuar como uma barreira geográfica no ciclo da Leishmania guyanensis. Com o objetivo de procurar possíveis diferenças biológicas entre populaçäes de L. umbratilis de margens opostas desse sistema fluvial, a biologia de duas populaçäes diferentes foi estudada em laboratório. Progenitores coletados em Manaus e Manacapuru (leste e oeste, respectivamente, do Rio Negro) foram criados separadamente. Resultados de observaçäes do ciclo de vida, fecundidade, fertilidade e longevidade de adultos a 27§C e 92% UR (umidade relativa) foram analisados por estatística descritiva, e testes z, t, U e c2. Embora as colônias de Manaus e Manacapuru tenham apresentado desenvolvimento mais demorado que a maioria das espécies de Lutzomyia, a duração das fases de ovo e de larva de 4§ estágio nas duas populaçäes foi significativamente (p < 0,01) diferente. Fêmeas de Manaus retiveram significativamente (p < 0.001) menos óvulos maduros, e a produtividade geral (% de adultos a partir de um número conhecido de ovos) da colônia foi significativamente (p < 0,01) mais alta do que a de Manacapuru. Estes resultados apontam a população de L. umbratilis de Manaus como a melhor candidata a futuras tentativas de criação em massa em laboratório. As diferenças observadas nas duas populaçäes quanto ao ciclo de vida, fecundidade, fertilidade, longevidade e emergência de adultos podem ser resultantes do isolamento geográfico ocasionado pelos grandes rios.

Association between EcoRI fragment-length polymorphism of the immunoglobulin lambda variable 8 (IGLV8) gene family with rheumatoid arthritis and systemic lupus erythematosus

The human immunoglobulin lambda variable 8 (IGLV8) subgroup is a gene family containing three members, one of them included in a monomorphic 3.7-kb EcoRI genomic fragment located at the major lambda variable locus on chromosome 22q11.1 (gene IGLV8a, EMBL accession No. Z73650) at 100 percent frequency in the normal urban population. The second is a polymorphic RFLP allele included in a 6.0-kb EcoRI fragment at 10 percent frequency, and the third is located in a monomorphic 8.0-kb EcoRI fragment at 100 percent frequency, the last being translocated to chromosome 8q11.2 and considered to be an orphan gene. Our Southern blot-EcoRI-RFLP studies in normal individuals and in patients with rheumatoid arthritis (RA) or with systemic lupus erythematosus (SLE), using a specific probe for the IGLV8 gene family (probe pVL8, EMBL accession No. X75424), have revealed the two monomorphic genomic fragments containing the IGLV8 genes, i.e., the 3.7-kb fragment from chromosome 22q11.1 and the 8.0-kb fragment from 8q11.2, both occurring at 100 percent frequency (103 normal individuals, 48 RA and 28 SLE patients analyzed), but absence of the 6.0-kb IGLV8 polymorphic RFLP allele in all RA or SLE patients. As expected, the frequency of the 6.0-kb allele among the normal individuals was 10 percent. These findings suggest an association between the absence of the 6.0-kb EcoRI fragment and rheumatoid arthritis and systemic lupus erythematosus