376 research outputs found

    Rapid Prototyping of Digital Controls for Power Electronics

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    The process for designing digital controls for power electronics is typically quite convoluted and affords many opportunities for errors to occur. We present here a new and complete, method for rapid prototyping of digital controls that allows rapid realization of new designs. The approach uses a collection of tools that include both software (the virtual test bed (VTB) and Matlab/Simulink) and hardware (dSpace DSP). An example application of the methodology completes the discussion

    Is the adjustable lumbo-peritoneal shunt a valid option for managing symptomatic idiopathic intracranial hypertension? A case report of a multidisciplinary management

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    Background: Idiopathic intracranial hypertension is a rare disorder, characterized by raised intracranial pressure with no recognizable cause. Headache, decreased visual acuity and papilledema are the main clinical manifestations. Case description: A case of a 27-year-old obese woman affected by idiopathic intracranial hypertension is reported. She was initially treated conservatively, but, due to severe headache refractory to medical therapy, an adjustable lumbo-peritoneal shunt was implanted. Conclusion: Gold standard treatment of idiopathic intracranial hypertension is not defined yet, but the lumbo-peritoneal shunt could represent a valid option for managing the disease in properly selected patients. Keywords: Lumbo-peritoneal shunt, Idiopathic intracranial hypertension, Pseudotumor cerebr

    Celecoxib inhibits proliferation and survival of chronic myelogeous leukemia (CML) cells via AMPK-dependent regulation of β-catenin and mTORC1/2.

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    CML is effectively treated with tyrosine kinase inhibitors (TKIs). However, the efficacy of these drugs is confined to the chronic phase of the disease and development of resistance to TKIs remains a pressing issue. The anti-inflammatory COX2 inhibitor celecoxib has been utilized as anti-tumour drug due to its anti-proliferative activity. However, its effects in hematological malignancies, in particular CML, have not been investigated yet. Thus, we tested biological effects and mechanisms of action of celecoxib in Philadelphia-positive (Ph+) CML and ALL cells.We show here that celecoxib suppresses the growth of Ph+ cell lines by increasing G1-phase and apoptotic cells and reducing S- and G2-phase cells. These effects were independent of COX2 inhibition but required the rapid activation of AMP-activated protein kinase (AMPK) and the consequent inhibition mTORC1 and 2. Treatment with celecoxib also restored GSK3β function and led to down-regulation of β-catenin activity through transcriptional and post-translational mechanisms, two effects likely to contribute to Ph+ cell growth suppression by celecoxib.Celecoxib inhibited colony formation of TKI-resistant Ph+ cell lines including those with the T315I BCR-ABL mutation and acted synergistically with imatinib in suppressing colony formation of TKI-sensitive Ph+ cell lines. Finally, it suppressed colony formation of CD34+ cells from CML patients, while sparing most CD34+ progenitors from healthy donors, and induced apoptosis of primary Ph+ ALL cells.Together, these findings indicate that celecoxib may serve as a COX2-independent lead compound to simultaneously target the mTOR and β-catenin pathways, key players in the resistance of CML stem cells to TKIs

    Prolonged abstinence from developmental cocaine exposure dysregulates BDNF and its signaling network in the medial prefrontal cortex of adult rats.

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    Although evidence exists that chronic cocaine exposure during adulthood is associated with changes in BDNF expression, whether and how cocaine exposure during adolescence modulates BDNF is still unknown. To address this issue, we exposed rats to repeated cocaine injections from post-natal day (PD) 28 to PD 42, a period that roughly approximates adolescence in humans, and we carried out a detailed analysis of the BDNF system in the medial prefrontal cortex (mPFC) of rats sacrificed 3 d (PD 45) and 48 d (PD 90) after the last cocaine treatment. We found that developmental exposure to cocaine altered transcriptional and translational mechanisms governing neurotrophin expression. Total BDNF mRNA levels, in fact, were enhanced in the mPFC of PD 90 rats exposed to cocaine in adolescence, an effect sustained by changes in BDNF exon IV through the transcription factors CaRF and NF-kB. While a profound reduction of specific BDNF-related miRNAs (let7d, miR124 and miR132) may contribute to explaining the increased proBDNF levels, the up-regulation of the extracellular proteases tPA is indicative of increased processing leading to higher levels of released mBDNF. These changes were associated with increased activation of the trkB-Akt pathway resulting in enhanced pmTOR and pS6 kinase, which ultimately produced an up-regulation of Arc and a consequent reduction of GluA1 expression in the mPFC of PD 90 cocaine-treated rats. These findings demonstrate that developmental exposure to cocaine dynamically dysregulates BDNF and its signaling network in the mPFC of adult rats, providing novel mechanisms that may contribute to cocaine-induced changes in synaptic plasticity

    Inducible forebrain-specific ablation of the transcription factor Creb during adulthood induces anxiety but no spatial/contextual learning deficits

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    The cyclic AMP (cAMP)-response element binding protein (CREB) is an activity-dependent transcription factor playing a role in synaptic plasticity, learning and memory, and emotional behavior. However, the impact of Creb ablation on rodent behavior is vague as e.g. memory performance of different Creb mutant mice depends on the specific type of mutation per se but additionally on the background and learning protocol differences. Here we present the first targeted ablation of CREB induced during adulthood selectively in principal forebrain neurons in a pure background strain of C57BL/6 mice. All hippocampal principal neurons exhibited lack of CREB expression. Mutant mice showed a severe anxiety phenotype in the openfield and novel object exploration test as well as in the Dark-Light Box Test, but unaltered hippocampus-dependent long-term memory in the Morris water maze and in context dependent fear conditioning. On the molecular level, CREB ablation led to CREM up regulation in the hippocampus and frontal cortex which may at least in part compensate for the loss of CREB. BDNF, a postulated CREB target gene, was down regulated in the frontal lobe but not in the hippocampus; neurogenesis remained unaltered. Our data indicate that in the adult mouse forebrain the late onset of CREB ablation can, in case of memory functionality, be compensated for and is not essential for memory consolidation and retrieval during adulthood. In contrast, the presence of CREB protein during adulthood seems to be pivotal for the regulation of emotional behavior

    Chronic treatment with fluoxetine up-regulates cellular BDNF mRNA expression in rat dopaminergic regions.

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    During the last few years several studies have highlighted the possibility that major depression can be characterized by a general reduction in brain plasticity and an increased vulnerability under challenging situations. Such dysfunction may be the consequence of reduced expression and function of proteins important for neuroplasticity such as brain-derived neurotrophic factor (BDNF). On this basis, by using a sensitive non-radioactive in-situ hybridization, we evaluated the effects of a chronic treatment with fluoxetine on BDNF expression within rat dopaminergic regions. In fact, besides the well-established role of the hippocampus, increasing evidence indicates that other brain regions may be involved in the pathophysiology of depression and consequently be relevant for the therapeutic action of antidepressant drugs. Our results indicate that 3 wk of fluoxetine administration up-regulates BDNF mRNA levels selectively within structures belonging to the meso-cortico-limbic pathway. The expression of the neurotrophin is significantly increased in the ventral tegmental area, prefrontal cortex, and shell region of the nucleus accumbens, whereas no changes were detected in the substantia nigra and striatum. Moreover, in agreement with previous studies, fluoxetine increased BDNF mRNA levels in the hippocampus, an effect that was limited to the cell bodies without any change in its dendritic targeting. These data show that chronic treatment with fluoxetine increases BDNF gene expression not only in limbic areas but also in dopaminergic regions, suggesting that such an effect may contribute to improve the function of the dopaminergic system in depressed subjects

    Depression, obesity and their comorbidity during pregnancy : effects on the offspring's mental and physical health

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    Depression and obesity represent two of the most common complications during pregnancy and are associated with severe health risks for both the mother and the child. Although several studies have analysed the individual effects of depression or obesity on the mothers and their children, the effects associated with the co-occurrence of both disorders have so far been poorly investigated. The relationship between depression and obesity is very complex and it is still unclear whether maternal depression leads to obesity or vice versa. It is well known that the intrauterine environment plays an important role in mediating the effects of both depression and obesity in the mother on the fetal programming, increasing the child's risk to develop negative outcomes.Peer reviewe

    Human proliferating cell nuclear antigen, poly(ADP-ribose) polymerase-1, and p21waf1/cip1. A dynamic exchange of partners.

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    We addressed the analysis of the physical and functional association of proliferating cell nuclear antigen (PCNA), a protein involved in many DNA transactions, with poly(ADP-ribose) polymerase (PARP-1), an enzyme that plays a crucial role in DNA repair and interacts with many DNA replication/repair factors. We demonstrated that PARP-1 and PCNA co-immunoprecipitated both from the soluble and the DNA-bound fraction isolated from S-phase-synchronized HeLa cells. Immunoprecipitation experiments with purified proteins further confirmed a physical association between PARP-1 and PCNA. To investigate the effect of this association on PARP-1 activity, an assay based on the incorporation of radioactive NAD was performed. Conversely, the effect of PARP-1 on PCNA-dependent DNA synthesis was assessed by a DNA polymerase delta assay. A marked inhibition of both reactions was found. Unexpectedly, PARP-1 activity also decreased in the presence of p21waf1/cip1. By pull-down experiments, we provided the first evidence for an association between PARP-1 and p21, which involves the C-terminal part of p21 protein. This association was further demonstrated to occur also in vivo in MNNG (N-methyl-N'-nitro-N-nitrosoguanidine)-treated human fibroblasts. These observations suggest that PARP-1 and p21 could cooperate in regulating the functions of PCNA during DNA replication/repair

    Modulation of BDNF expression by repeated treatment with the novel antipsychotic lurasidone under basal condition and in response to acute stress

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    Abstract It is known that long-term treatment with antipsychotic drugs (APDs) produces neuroadaptive changes through the modulation of different proteins that, by enhancing neuronal plasticity and cellular resiliency, may improve core disease symptoms. The aim of this study was to investigate the ability of chronic treatment with the novel antipsychotic lurasidone to modulate BDNF expression in hippocampus and prefrontal cortex, under basal conditions or in response to an acute stress, a major precipitating element in psychiatric disorders. By means of real-time PCR, we found that (1) chronic lurasidone treatment increases total BDNF mRNA levels in rat prefrontal cortex and, to less extent, in hippocampus ; (2) the modulation of BDNF mRNA levels in response to acute swim stress in lurasidone-treated rats was markedly potentiated in hippocampus, and to less extent in prefrontal cortex, through the selective regulation of different neurotrophin isoforms. The increase of BDNF mRNA levels in prefrontal cortex was paralleled by an enhancement of mature BDNF protein levels. In conclusion, repeated exposure to lurasidone regulates BDNF expression, through a finely tuned modulation of its transcripts. This effect may contribute to the amelioration of functions, such as cognition, closely associated with neuronal plasticity, which are deteriorated in schizophrenia patients
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