Correlação entre ressonância magnética, expressão do Ki-67 e p53, e prognóstico em astrocitomas / Correlation between Magnetic Ressonance Image, Expression of Ki-67 and p53, and Prognosis in Astrocytomas

Objetivos Avaliar a correlação entre a expressão do Ki-67 e do p53 em astrocitomas graus II a IV, as características da RM e seu prognóstico. Métodos e Resultados Este é um estudo longitudinal retrospectivo do tipo coorte histórico que avaliou 45 pacientes. O prognóstico foi avaliado mediante revisão dos prontuários. A avaliação imuno-histoquímica foi realizada no Serviço de Patologia do HB. A avaliação das imagens de RMfoi feita no Serviço de Radiologia. A sobrevidamédia dos pacientes foi de 581,4 dias no grau IV; 1.704,8 dias no grau III; e 1.044,8 dias no grau II. Para cada grau, os seguintes percentuais de células positivas de Ki-67 e p53 tiveram respectivamente: 97,8 e 80% de positividade no grau IV; 72,7 e 73,4% de positividade no grau III; e 70 e 80% de positividade no grau II. Observou-se diferença estatística na expressão de Ki-67 entre os graus III e IV (P » 0,014). A RM mostrou especificidade de 64% e sensibilidade de 100% para a presença de necrose tumoral. Conclusão Concluímos que a análise da positividade do Ki-67 e do p53 não permite sua correlação com a sobrevida dos pacientes, apesar de ambos terem sua frequência distribuída de maneira semelhante. A RM tem especificidade moderada em relação ao exame patológico.rada em relação ao exame patológico.

Objectives To evaluate the correlation between the expression of Ki -67 and p53 in astrocytomas grades II to IV, the characteristics of MRI and its prognosis. Methods This was a retrospective longitudinal cohort study of its kind that evaluated 45 patients. Prognosis was assessed by review of medical records. The immunohistochemical evaluation was performed at the Pathology Service of HB. The evaluation of MRI images was taken in the Radiology Department. The median survival of patients was 581.4 days in grade IV; 1704.8 days in grade III; 1044.8 days in grade II. For each grade, the following percentages of cells positive for Ki -67 and p53 , respectively : 97.8% and 80% had a positive grade IV ; 72.7% and 73.4% positivity in grade III ; 70% and 80% in stage II positivity . There was statistical difference in Ki -67 between grades III and IV (P » 0.014).MRI showed 64% specificity and 100% sensitivity for the presence of tumor necrosis Conclusion We conclude that the analysis of the positivity of Ki -67 and p53 expression does not allow correlation with patient survival, although both their frequency distributed similarly. MRI hasmoderate specificity in relation to pathological examination.

A human astrocytoma cell line is highly susceptible to infection with Trypanosoma cruzi

Astrocytes play a vital role in neuronal protection, homeostasis, vascular interchange and the local immune response. Some viruses and parasites can cross the blood-brain barrier and infect glia. Trypanosoma cruzi, the aetiological agent of Chagas disease, can seriously compromise the central nervous system, mainly in immune-suppressed individuals, but also during the acute phase of the infection. In this report, the infective capacity of T. cruzi in a human astrocyte tumour-derived cell line was studied. Astrocytes exposed to trypomastigotes (1:10 ratio) produced intracellular amastigotes and new trypomastigotes emerged by day 4 post-infection (p.i.). At day 6 p.i., 93% of the cells were infected. Using flow cytometry, changes were observed in both the expression of major histocompatibility complex class I and II molecules and the chemokine secretion pattern of astrocytes exposed to the parasite. Blocking the low-density lipoprotein receptor on astrocytes did not reduce parasite intracellular infection. Thus, T. cruzi can infect astrocytes and modulate the immune response during central nervous system infection.