Clinical and demographic characteristics of Epstein-Barr virus-associated childhood Burkitt's lymphoma in Southeastern Brazil: epidemiological insights from an intermediate risk region.

We studied a group of 54 children with Burkitt's lymphoma from Southeastern Brazil, where epidemiological status of Burkitt's lymphoma is poorly understood. Epstein-Barr virus association showed an intermediate frequency (~60%) between endemic and sporadic subtypes. Median age was five years. Epstein-Barr virus infection was significantly associated to low age (Epstein-Barr virus(+) four years vs. Epstein-Barr virus(-) eight years). Sex ratio (M:F) was 2:1, with a significantly higher number of males in old age classes. Young age at diagnosis and excess of males at older ages, as well as a causal relationship between low age, epstein-barr virus and Burkitt's lymphoma risk, may characterize Burkitt's lymphoma in Brazil.

Burkitt lymphoma/leukaemia transformed from a precursor B cell: clinical and molecular aspects.

Burkitt lymphoma/leukaemia (BL/L) is a heterogeneous disease with respect to epidemiological patterns and cell origin. The occurrence of BL/L with an immature phenotype raises the question whether this phenotype might be a consequence of early B-cell transformation or, alternatively, a secondary feature of transformed, mature B cells. It also poses important clinical questions regarding diagnosis and therapeutic procedures. Here we describe the case of a 4-yr-old child with BL/L and FAB L3 morphology, with phenotypic and genotypic characteristics of a CD10+ precursor B-cell acute lymphoid leukaemia (ALL) associated with t(8;14)(q24;q32). Molecular analysis showed expression of RAG1 and RAG2 and an unmutated VDJCmu immunoglobulin rearrangement coinciding with a lack of AICDA expression, indicating an immature B-cell origin. His clinical response suggested that FAB L3 ALL with MYC rearrangement and an aberrant precursor B-cell phenotype is clinically similar to BL/L. Moreover, short, intensive chemotherapeutic protocols seemed to be beneficial. This case also allowed us to refine the description of cellular and molecular variants of BL/L regarding the cell origin and pathogenesis of this biologically heterogeneous disease.

Influence of the estrous cycle on the behavior of rats in the elevated T-maze.

The elevated T-maze is an animal anxiety model which can discriminate between anxiety-like and fear-like behaviors. The estrous cycle is an important variable of the response in animal anxiety tests and is known to affect other models. The aim of the present study was to investigate the influence of the estrous cycle on behavior displayed in the elevated T-maze test. Seventeen male and 60 female rats were submitted to one session in this test, with the females being screened for the estrous cycle and divided into groups according to the various phases. The elevated T-maze had three arms of equal dimensions ( 50 cm x 10 cm), one enclosed by 40-cm high walls and perpendicular to the others, the apparatus being elevated 50 cm above the floor. Each rat was placed in the end of the enclosed arm and the latency for it to leave this arm was recorded. These measurements were repeated three times separated by 30-s intervals (passive avoidance). After trial 3, each rat was placed at the distal end of the right open arm and the latency to exit this arm was recorded. Whenever latencies were greater than 300 s the trial was finished. The results demonstrated females in diestrus exhibited anxiety-like behaviors while females in metaestrus behaved in a similar way as the males. There were no differences between groups in fear-like behaviors. The results also indicate the elevated T-maze to be a sensitive test to measure anxiety.

Epstein-Barr virus (EBV) detection and typing by PCR: a contribution to diagnostic screening of EBV-positive Burkitt's lymphoma.

BACKGROUND: Epstein-Barr virus (EBV) is associated to the etio-pathogenesis of an increasing number of tumors. Detection of EBV in pathology samples is relevant since its high prevalence in some cancers makes the virus a promising target of specific therapies. RNA in situ hybridization (RISH) is the standard diagnostic procedure, while polymerase chain reaction (PCR)-based methods are used for strain (EBV type-1 or 2) distinction. We performed a systematic comparison between RISH and PCR for EBV detection, in a group of childhood B-cell Non-Hodgkin lymphomas (NHL), aiming to validate PCR as a first, rapid method for the diagnosis of EBV-associated B-cell NHL. METHODS: EBV infection was investigated in formalin fixed paraffin-embedded tumor samples of 41 children with B-cell NHL, including 35 Burkitt's lymphoma (BL), from Rio de Janeiro, Brazil, by in situ hybridization of EBV-encoded small RNA (EBER-RISH) and PCR assays based on EBNA2 amplification. RESULTS: EBV genomes were detected in 68% of all NHL. Type 1 and 2 accounted for 80% and 20% of EBV infection, respectively. PCR and RISH were highly concordant (95%), as well as single- and nested-PCR results, allowing the use of a single PCR round for diagnostic purposes. PCR assays showed a sensitivity and specificity of 96% and 100%, respectively, with a detection level of 1 EBV genome in 5,000-10,000 EBV-negative cells, excluding the possibility of detecting low-number EBV-bearing memory cells. CONCLUSION: We describe adequate PCR conditions with similar sensitivity and reliability to RISH, to be used for EBV diagnostic screening in high grade B-NHL, in "at risk" geographic regions.