Tobias Alécio Mattei

Edema and malignancy in meningiomas

PURPOSEnIn recent years there have been many attempts to define a subset of aggressive malignant meningiomas based on histopathology and imaging technologies. The purpose of this study was to evaluate the level of peritumoral edema and its volume using the imaging technologies, computer tomography and magnetic resonance imaging, and correlate these results with the histological WHO classification. Reported causes of tumoral edema and its relationships to the histological characteristics were also reviewed.nnnMETHODSnThe cases of 55 patients with meningiomas who underwent surgery at the Hospital das Clinicas (Fac Med Univ Sao Paulo) between September 1993 and September 1997 were reviewed. The level of edema according to the classification of Ide et al. (1995) was compared to the histological WHO classification.nnnRESULTSnClassification of the degree of edema was: level 0 edema--28 cases ; level I edema--19 cases; level II edema--8 cases. Histological classification was: benign meningioma--43 cases; atypical meningiomas--11 cases; malignant meningioma--1 case. There was a significant (P=.0089) correlation between the degree of tumoral edema and the histological characteristics.nnnCONCLUSIONSnThese results suggest that the degree of edema as revealed by computer tomography and magnetic resonance imaging can be an important clinical predictive factor for the histological grade of the meningioma.

Past, present and future perspectives of genetic therapy in gliomas

High-grade gliomas are relatively frequent in adults and consist in the most malignant form of primary brain tumor. They are resistant to standard treatment modalities such as surgery, radiation, and chemotherapy, being fatal within 1 to 2 years of onset of symptoms. Owing to the promising practical clinical benefits that can be expected for the near future, an exposition of the basic issues in genetic therapy of gliomas seems timely. In this article we intend to provide a general review that covers the most important genes already studied as possible agents for genetic therapy in gliomas. In a critical analysis we intend to expose and discuss anti-tumoral mechanisms and therapeutical results of studies with the following class of genes: prodrug activation systems, apoptosis-related genes, anti-angiogenic factors genes, radiosensitization genes, chemosensitization genes, apoptosis-related genes and immunogenes. Finally we discuss the historical importance, actual role and further developments that can be expected from each of these class of agents for the future of genetic therapy of gliomas.

Diagnóstico e conduta cirúrgica nos meningiomas de tubérculo selar

Os meningiomas do tuberculo selar, juntamente com os da goteira olfatoria, estao entre os tumores mais frequentes da fossa craniana anterior. Os sintomas caracteristicos sao deficits visuais, disturbios do comportamento, crises epilepticas, anosmia e deficits motores. Devido a seu crescimento lento, o periodo do inicio dos sintomas ate o diagnostico tende a ser longo, geralmente excedendo dois anos. Quando o tumor atinge mais de 4 cm e comprime as estruturas neurovasculares adjacentes, a possibilidade de remocao cirusrgica total e limitada e a chance de melhora na funcao visual e baixa. O tratamento ideal de meningiomas de tuberculo selar e a resseccao completa do tumor com descompressao dos vasos e parenquima cerebral adjacentes. Em virtude da escassez de grupos experientes especializados em cirurgia da base do crânio, muitos dos pacientes portadores de meningiomas de tuberculo selar sao tratados em alguns centros com procedimentos alternativos, os quais apresentam resultados significativamente piores as series cirurgicas mais recentes publicadas ma literatura. Neste artigo, os autores apresentam um panorama geral acerca dos metodos diagnosticos para deteccao e avaliacao pre-operatoria dos meningiomas de tuberculo selar. Tambem sao enfatizados os beneficios do tratamento cirurgico, o qual, se realizado por uma equipe experiente, pode ser curativo, apresentando menor morbidade que outras modalidades terapeuticas.

Genetic therapy in gliomas: Historical analysis and future perspectives

High-grade gliomas are relatively frequent in adults, and consist of the most malignant kind of primary brain tumor. Being resistant to standard treatment modalities such as surgery, radiation, and chemotherapy, it is fatal within 1 to 2 years of onset of symptoms. Although several gene therapy systems proved to be efficient in controlling or eradicating these tumors in animal models, the clinical studies performed so far were not equally successful. Most clinical studies showed that methodologies that increase tumor infection/transduction and, consequently confer more permanent activity against the tumor, will lead to enhanced therapeutic results. Due to the promising practical clinical benefits that can be expected for the near future, an exposition to the practicing neurosurgeon about the basic issues in genetic therapy of gliomas seems convenient. Among the main topics, we shall discuss anti-tumoral mechanisms of various genes that can be transfected, the advantages and drawbacks of the different vectors utilized, the possibilities of tumor targeting by modifications in the native tropism of virus vectors, as well as the different physical methods for vector delivery to the tumors. Along with the exposition we will also review of the history of the genetic therapy for gliomas, with special focus on the main problems found during the advancement of scientific discoveries in this area. A general analysis is also made of the present state of this promising therapeutic modality, with reference to the problems that still must be solved and the new paradigms for future research in this area.