IDH1 and IDH2 mutations in different histologic subtypes and WHO grading gliomas in a sample from Northern Brazil.

Glioma is a term used to describe tumors derived from glial cells. These tumors are divided into subgroups based on the histological morphology and similarity of their differentiated glia cells. Traditionally, they are classified according to the World Health Organization and include astrocytomas, oligodendrogliomas, ependymomas, and oligoastrocytomas. Like most cancers, gliomas develop as a result of genetic changes that accumulate with tumor progression. Alterations in isocitrate dehydrogenase 1 (IDH1) and IDH2 were found to be relevant in the classification and prognostic of gliomas. Because of the importance of mutations in these genes, particularly in IDH1, in different proposals of the genesis and progression of gliomas, we analyzed the occurrence of mutations in these genes in samples obtained from patients from Belém (PA, Brazil) using polymerase chain reaction-single-strand conformation polymorphism followed by sequencing. We compared the results obtained from tumors of different malignancy grades, evaluating the significance of the associations between different variables. R132H was the only mutation found in 17.6% (6/34) of cases, including in astrocytomas, anaplastic astrocytomas, oligodendroglioma, and anaplastic oligoastrocytoma. No mutations were found in the IDH2 gene. We found no significant relationship between the identified mutations in IDH1 and the variables. Our data could not confirm that mutations in IDH1/IDH2 are indicative of malignancy and prognosis. However, the results support that the mutation in IDH1 gene was an early event in the development of gliomas, as it was found in tumors of different malignancy grades.

A contribution to the establishment of reference values for total mercury levels in hair and fish in amazonia.

Studies on mercury levels in the Amazonian Region have typically lacked background or reference parameters. A sectional study on Hg concentration in hair and fish was conducted, together with an assessment of the prevalence of signs and symptoms related to Hg poisoning, in four communities in the Amazon Basin not impacted by gold mining, located either by a river course (Santana do Ituqui and Caxiuanã) or by a lake (Aldeia do Lago Grande and Vila do Tabatinga). Mercury determinations in hair and fish were made by flameless atomic absorption spectrophotometry. Mean total Hg in hair was 4.33 microg/g (0.40-11.60 microg/g) in 321 individuals from Santana do Ituqui, 3.98 microg/g (0.40-11.76 microg/g) for 316 persons in Aldeia do Lago Grande, 5.46 microg/g (0.37-49.85 microg/g) for 504 individuals from Vila do Tabatinga and 8.58 microg/g (0.61-45.59 microg/g) for 203 inhabitants from Caxiuanã. Fish consumption was very high in all those communities but no signs or symptoms associated with Hg poisoning were found. Mean Hg concentration in fish varied from 0.006 to 2.529 microg/g for carnivores and from 0.008 to 0.871 microg/g for noncarnivores. These values suggest that further studies including a larger number of communities would eventually lead to values of "normal" Hg concentration in the Amazonian Region quite above the limits suggested by the World Health Organization.

The expression of ABH and Lewis antigens in Brazilian semi-isolated Black communities

The expression of the ABH and Lewis blood groups was determined in blood and saliva samples from two semi-isolated Black communities of Northern Brazil: Cametá and Alcântara. The distributions of ABO blood group phenotypes and the ABH secretor status frequencies showed no significant differences between these populations. In contrast, there was a difference regarding the frequency of the red blood cell Le(a-b-) phenotypes, associated with erythrocyte/saliva discordance, as confirmed by the observation that individuals with Le(a-b-) red cells have the Lewis antigen in their saliva, resulting in a nongenuine Le(a-b-) phenotype, whose frequency was higher in Alcântara