RESUMO
Aquaporin-4 (AQP-4), the most important water channel in the brain, is expressed by astrocyte end feet abutting microvessels. Altered expression levels of AQP-4 and redistribution of the protein throughout the membranes of cells found in glioblastoma multiforme (GBM) lead to development of the edema often found surrounding the tumor mass. Dysregulation of AQP-4 also occurs in hippocampal sclerosis and cortical dysplasia in patients with refractory partial epilepsy. This work reports on analysis of the relationship between AQP-4 expression and the incidence of epileptic seizures in patients with GBM. Immunohistochemical and polymerase chain reaction techniques were used to evaluate AQP-4 in biopsy specimens from 19 patients with GBM, 10 of who had a history of seizures before surgery. AQP-4 mRNA levels were identical in the two groups of patients, but AQP-4 expression was more frequently detected on the GBM membranes from specimens of patients with seizures than from individuals without (10 versus 2, P < 0.001). We conclude that reduced expression of cell surface AQP-4 is characteristic of GBM patients without seizures, likely attributable to a posttranslational mechanism.
Assuntos
Aquaporina 4/genética , Aquaporina 4/metabolismo , Glioblastoma/complicações , Glioblastoma/genética , Convulsões/complicações , Adulto , Idoso , Idoso de 80 Anos ou mais , Edema Encefálico/complicações , Edema Encefálico/genética , Edema Encefálico/patologia , Neoplasias Encefálicas/complicações , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Demografia , Feminino , Regulação Neoplásica da Expressão Gênica , Glioblastoma/patologia , Humanos , Imuno-Histoquímica , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Convulsões/patologiaRESUMO
A patient with neurological symptoms underwent CT scan that showed a sellar and suprasellar mass with bone erosions, involving especially the clivus and the right petrous apex. The first diagnostic hypothesis was chordoma in relation to the mass position. The MRI showed a solid well-enhancing mass; moreover another circumscribed lesion, with similar signal pattern, was found in the left mandibular condyle. the signal and the presence of another lesion did not agree with diagnosis of chordoma. FDG-PET/CT study showed multiple pathological uptakes suggesting a metastatic disease. A trans-sphenoidal excisional biopsy was performed and the histopathological analysis showed a population of cells consistent with a plasmacell tumor, confirmed by the presence of a monoclonal gammopathy on blood analysis. Our case suggests that FDG-PET/CT can modify the diagnostic and therapeutic procedures in myeloma, by evaluating the bone marrow involvement.
