53 research outputs found

    Secondary meningioma in a long-term survivor of atypical teratoid/rhabdoid tumour with a germline INI1 mutation

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    OBJECTIVE: We report on a patient who developed a meningioma more than two decades after removal at a young age of an atypical teratoid/rhabdoid tumour (AT/RT), which was due to a germline INI1 mutation, and radio- and chemotherapy. MATERIALS AND METHODS: We present genetic evidence that the meningioma is not a recurrence or metastasis of the AT/RT and not due to the INI1 mutation, but is a radiation-induced tumour. CONCLUSION: This is the first case illustrating that improved survival of young patients with an AT/RT after aggressive treatment may be gained at the cost of an increased risk for the development of radiation-induced, non-INI1-related tumours

    A Fear-Inducing Odor Alters PER2 and c-Fos Expression in Brain Regions Involved in Fear Memory

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    Evidence demonstrates that rodents learn to associate a foot shock with time of day, indicating the formation of a fear related time-stamp memory, even in the absence of a functioning SCN. In addition, mice acquire and retain fear memory better during the early day compared to the early night. This type of memory may be regulated by circadian pacemakers outside of the SCN. As a first step in testing the hypothesis that clock genes are involved in the formation of a time-stamp fear memory, we exposed one group of mice to fox feces derived odor (TMT) at ZT 0 and one group at ZT 12 for 4 successive days. A separate group with no exposure to TMT was also included as a control. Animals were sacrificed one day after the last exposure to TMT, and PER2 and c-Fos protein were quantified in the SCN, amygdala, hippocampus, and piriform cortex. Exposure to TMT had a strong effect at ZT 0, decreasing PER2 expression at this time point in most regions except the SCN, and reversing the normal rhythm of PER2 expression in the amygdala and piriform cortex. These changes were accompanied by increased c-Fos expression at ZT0. In contrast, exposure to TMT at ZT 12 abolished the rhythm of PER2 expression in the amygdala. In addition, increased c-Fos expression at ZT 12 was only detected in the central nucleus of the amygdala in the TMT12 group. TMT exposure at either time point did not affect PER2 or c-Fos in the SCN, indicating that under a light-dark cycle, the SCN rhythm is stable in the presence of repeated exposure to a fear-inducing stimulus. Taken together, these results indicate that entrainment to a fear-inducing stimulus leads to changes in PER2 and c-Fos expression that are detected 24 hours following the last exposure to TMT, indicating entrainment of endogenous oscillators in these regions. The observed effects on PER2 expression and c-Fos were stronger during the early day than during the early night, possibly to prepare appropriate systems at ZT 0 to respond to a fear-inducing stimulus

    The evidence for hippocampal long-term potentiation as a basis of memory for simple tasks

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    Encoding process in delayed recall impairment and rate of forgetting in Alzheimer's disease Comprometimento da codificação na deficiência de memória tardia e taxa de esquecimento na doença de Alzheimer

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    OBJECTIVE: To assess the role of impaired encoding in learning and in delayed recall disturbances, and to evaluate the rate of forgetting in AD. METHOD: Fifteen AD patients with mild or moderate dementia and 15 normal matched controls were assessed with the Buschke Selective Reminding Test. Delayed recall was evaluated after 30 minutes and after 24 hours. RESULTS: AD patients had a poorer performance across the six trials of the learning phase as well as in both delayed recall evaluations, with no difference between recall at 30 minutes and at 24 hours. CONCLUSION: Performance in the learning phase was as specific and almost as sensitive as the performance in delayed recall for AD diagnosis. Encoding impairment was responsible for poorer learning and rapid displacement of previous learned material in the AD group. Finally, we did not find a higher rate of forgetting in AD patients.<br>OBJETIVO: Investigar o papel do distúrbio da codificação nas deficiências de aprendizado e de memória e avaliar a taxa de esquecimento na doença de Alzheimer (DA). MÉTODO: Quinze pacientes com DA leve e moderada e 15 controles normais pareados foram avaliados pelo teste de memória seletiva de Buschke. A memória tardia foi avaliada depois de 30 minutos e depois de 24 horas. RESULTADOS: Os pacientes com DA apresentaram desempenho inferior no aprendizado e na memória tardia. A taxa de esquecimento entre 30 minutos e 24 horas não foi diferente entre pacientes e controles. CONCLUSÃO: O desempenho na fase de aprendizado mostrou-se tão específico e quase tão sensível quanto o desempenho na memória tardia para o diagnóstico da DA. O distúrbio da codificação foi considerado responsável pelo distúrbio de aprendizado na DA. Após a memorização, o esquecimento não foi mais pronunciado na DA, nas primeiras 24 horas
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