Comparison between qualitative and real-time polymerase chain reaction to evaluate minimal residual disease in children with acute lymphoblastic leukemia

Introduction: Minimal residual disease is an important independent prognostic factor that can identify poor responders among patients with acute lymphoblastic leukemia. Objective: The aim of this study was to analyze minimal residual disease using immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements by conventional polymerase chain reaction followed by homo-heteroduplex analysis and to compare this with real-time polymerase chain reaction at the end of the induction period in children with acute lymphoblastic leukemia. Methods: Seventy-four patients diagnosed with acute lymphoblastic leukemia were enrolled. Minimal residual disease was evaluated by qualitative polymerase chain reaction in 57 and by both tests in 44. The Kaplan-Meier and multivariate Cox methods and the log-rank test were used for statistical analysis. Results: Nine patients (15.8%) were positive for minimal residual disease by qualitative polymerase chain reaction and 11 (25%) by real-time polymerase chain reaction considering a cut-off point of 1 × 10−3 for precursor B-cell acute lymphoblastic leukemia and 1 × 10−2 for T-cell acute lymphoblastic leukemia. Using the qualitative method, the 3.5-year leukemia- free survival was significantly higher in children negative for minimal residual disease compared to those with positive results (84.1% ± 5.6% versus 41.7% ± 17.3%, respectively; p-value = 0.004). There was no significant association between leukemia-free survival and minimal residual disease by real-time polymerase chain reaction. Minimal residual disease by qualitative polymerase chain reaction was the only variable significantly correlated to leukemia-free survival. Conclusion: Given the difficulties in the implementation of minimal residual disease monitoring by real-time polymerase chain reaction in most treatment centers in Brazil, the qualitative polymerase chain reaction strategy may be a cost-effective alternative.

Perspectivas para o desenvolvimento de investigação científica em Educação Médica / Prospects for the development of scientific research in Medical Education

Pretende-se, com este texto, apresentar aos profissionais envolvidos na docência e formação médica potenciais temas de pesquisa científica na área da Educação Médica. É premente a necessidade de promover a competência docente nesta área de forma a compreendê-la como um campo profícuo de investigação e condução de estudos experimentais.

This text intends to present potential themes of scientific research, in the area of medical education, to professionals involved in teaching and medical training. The need to promote teaching competencies in this area is pressing in order to understand it as a fruitful of research, and execute experimental studies.

Revisando a descoberta do sinal de Romaña / Reviewing the discovery of signal Romaña

Revisões históricas aos avanços científicos para o controle da doença, o Simpósio Internacional Comemorativo do Centenário da Descoberta da Doença de Chagas (1909-2009).

Anticorpos antipromastigotas vivas de Leishmania (Viannia) braziliensis, detectados pela citometria de fluxo, para identificaçäo da infecção ativa na leishmaniose tegumentar americana / Anti-live Leishmania (Viannia) braziliensis promastigote antibodies, detected by flow cytometry, to identify active infection in american cutaneous leishmaniasis

Neste estudo, descrevemos etapas iniciais de padronizaçäo de uma nova metodologia para detecçäo de anticorpos antipromastigotas vivas de Leishmania (Viannia) braziliensis, pela citometria de fluxo e a análise de sua aplicabilidade para estudos clínicos. Foram avaliados 39 indivíduos com sorologia convencional (RIFI) positiva para leishmaniose, classificados quanto à ausência/presença de lesäo (L- e L+). Os resultados foram expressos sob a forma de percentual de parasitas fluorescentes positivos (PPFP). A análise dos dados, na diluiçäo 1:1.024, permitiu distinguir 95 por cento dos pacientes L+ como um grupo de alta reatividade (PPFP>50 por cento) e 72 por cento dos indivíduos L- como um grupo de baixa reatividade (PPFP<=50 por cento). A análise dos títulos da reaçäo de imunofluorescência indireta näo demonstrou nenhuma relaçäo com a ausência/presença de lesäo. Em conjunto, nossos dados sugerem a aplicabilidade da citometria de fluxo na identificaçäo dos casos de infecçäo ativa, o que näo tem sido possível através das reaçöes sorológicas convencionais