390 research outputs found

    Tetrodotoxin-resistant sodium channels in sensory neurons generate slow resurgent currents that are enhanced by inflammatory mediators

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    Resurgent sodium currents contribute to the regeneration of action potentials and enhanced neuronal excitability. Tetrodotoxin-sensitive (TTX-S) resurgent currents have been described in many different neuron populations, including cerebellar and dorsal root ganglia (DRG) neurons. In most cases, sodium channel Nav1.6 is the major contributor to these TTX-S resurgent currents. Here we report a novel TTX-resistant (TTX-R) resurgent current recorded from rat DRG neurons. The TTX-R resurgent currents are similar to classic TTX-S resurgent currents in many respects, but not all. As with TTX-S resurgent currents, they are activated by membrane repolarization, inhibited by lidocaine, and enhanced by a peptide-mimetic of the β4 sodium channel subunit intracellular domain. However, the TTX-R resurgent currents exhibit much slower kinetics, occur at more depolarized voltages, and are sensitive to the Nav1.8 blocker A803467. Moreover, coimmunoprecipitation experiments from rat DRG lysates indicate the endogenous sodium channel β4 subunits associate with Nav1.8 in DRG neurons. These results suggest that slow TTX-R resurgent currents in DRG neurons are mediated by Nav1.8 and are generated by the same mechanism underlying TTX-S resurgent currents. We also show that both TTX-S and TTX-R resurgent currents in DRG neurons are enhanced by inflammatory mediators. Furthermore, the β4 peptide increased excitability of small DRG neurons in the presence of TTX. We propose that these slow TTX-R resurgent currents contribute to the membrane excitability of nociceptive DRG neurons under normal conditions and that enhancement of both types of resurgent currents by inflammatory mediators could contribute to sensory neuronal hyperexcitability associated with inflammatory pain

    Poor maternal nutrition programmes a pro-atherosclerotic phenotype in ApoE-/- mice.

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    Numerous animal studies have consistently shown that early life exposure to LP (low-protein) diet programmes risk factors for CVD (cardiovascular disease) such as dyslipidaemia, high BP (blood pressure) and cardiac dysfunction in the offspring. However, studies on the effect of maternal under-nutrition on offspring development of atherosclerosis are scarce. Applying our LP model to the ApoE(-/-) atherosclerosis-prone mouse model, we investigated the development of atherosclerotic lesions in the aortic root of 6-month-old offspring. In addition, markers of plaque progression including SMA (smooth muscle actin) and Mac3 (macrophage marker 3) were studied. Pregnant dams were fed on a control (20% protein) or on an isocaloric LP diet (8% protein) throughout pregnancy and lactation. After weaning, male offspring were maintained on 20% normal laboratory chow. At 6 months of age, LP offspring showed a significantly greater plaque area (P<0.05) with increased cholesterol clefts and significantly higher indices of DNA damage compared with controls (P<0.05). The expression of HMG-CoA reductase (3-hydroxy-3-methyl-glutaryl-CoA reductase) (P<0.05) and LDL (low-density lipoprotein) receptor in the liver of LP offspring were increased. Furthermore, LP offspring had higher LDL-cholesterol levels (P<0.05) and a trend towards elevated insulin. There were no differences in other lipid measurements and fasting glucose between groups. These observations suggest that early exposure to an LP diet accelerates the development and increases the progression of atherosclerotic lesions in young adult offspring. Future studies are needed to elucidate the specific mechanisms linking in utero exposure to a diet low in protein to the development of atherosclerosis.This work was supported by the British Heart Foundation [grant numbers FS/09/029/27902, FS/09/050], the Biotechnology and Biological Sciences Research Council and the Cambridge Commonwealth Trust

    Romidepsin in peripheral and cutaneous T-cell lymphoma: mechanistic implications from clinical and correlative data

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    Romidepsin is an epigenetic agent approved for the treatment of patients with cutaneous or peripheral T-cell lymphoma (CTCL and PTCL). Here we report data in all patients treated on the National Cancer Institute 1312 trial, demonstrating long-term disease control and the ability to retreat patients relapsing off-therapy. In all, 84 patients with CTCL and 47 with PTCL were enrolled. Responses occurred early, were clinically meaningful and of very long duration in some cases. Notably, patients with PTCL receiving romidepsin as third-line therapy or later had a comparable response rate (32%) of similar duration as the total population (38%). Eight patients had treatment breaks of 35months to 10years; in four of six patients, re-initiation of treatment led to clear benefit. Safety data show slightly greater haematological and constitutional toxicity in PTCL. cDNA microarray studies show unique individual gene expression profiles, minimal overlap between patients, and both induction and repression of gene expression that reversed within 24h. These data argue against cell death occurring as a result of an epigenetics-mediated gene induction programme. Together this work supports the safety and activity of romidepsin in T-cell lymphoma, but suggests a complex mechanism of action

    Can Doubly Strange Dibaryon Resonances be Discovered at RHIC?

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    The baryon-baryon continuum invariant mass spectrum generated from relativistic nucleus + nucleus collision data may reveal the existence of doubly-strange dibaryons not stable against strong decay if they lie within a few MeV of threshold. Furthermore, since the dominant component of these states is a superposition of two color-octet clusters which can be produced intermediately in a color-deconfined quark-gluon plasma (QGP), an enhanced production of dibaryon resonances could be a signal of QGP formation. A total of eight, doubly-strange dibaryon states are considered for experimental search using the STAR detector (Solenoidal Tracker at RHIC) at the new Relativistic Heavy Ion Collider (RHIC). These states may decay to Lambda-Lambda and/or proton-Cascade-minus, depending on the resonance energy. STAR's large acceptance, precision tracking and vertex reconstruction capabilities, and large data volume capacity, make it an ideal instrument to use for such a search. Detector performance and analysis sensitivity are studied as a function of resonance production rate and width for one particular dibaryon which can directly strong decay to proton-Cascade-minus but not Lambda-Lambda. Results indicate that such resonances may be discovered using STAR if the resonance production rates are comparable to coalescence model predictions for dibaryon bound states.Comment: 28 pages, 5 figures, revised versio

    EXPRESSÃO DAS CADERINAS NOS TUMORES MAMÁRIOS EM CADELAS

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    Mammary tumors are among the mostcommon neoplasia of canine females. The occurrenceof metastasis may be detected by proteic markers.Among them, exist the E-cadherin, a member ofcadherin family known for its important role in theregulation of intercellular adhesion in epithelial tissues.Studies suggest that E-cadherin may function as atumor and invasion suppressor molecule. Cadherinactivity is regulated by multiple mechanisms, includinginteraction with other proteins such as catenins. In thisreview, the authors approach the cadherin family andother related adhesion proteins including its function,physiopathology and potential use as marker fordiagnosis and prognosis of canine mammary tumors.Key words: cadherin, immunohistochemistry,As neoplasias mamárias são as que maisacometem as cadelas. O desenvolvimento do câncerpode levar à ocorrência de metástases que podemser detectadas por marcadores protéicos. Um destesmarcadores é a E-caderina, um membro da famíliadas caderinas conhecida por desempenhar um papelimportante na regulação da adesão intercelular emtecidos epiteliais. Estudos apontam que as E-caderinaspodem funcionar como moléculas supressorasde tumor e de invasão. A atividade das caderinas éregulada por múltiplos mecanismos, incluindo a interaçãocom outras proteínas como as cateninas. Nestarevisão os autores abordam a família das caderinas,incluindo sua função, fisiopatologia e potencial usocomo marcadores de diagnóstico e prognóstico nasneoplasias mamárias na cadela

    Calcinose circunscrita em cão

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    Electrically-driven phase transition in magnetite nanostructures

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    Magnetite (Fe3_{3}O4_{4}), an archetypal transition metal oxide, has been used for thousands of years, from lodestones in primitive compasses[1] to a candidate material for magnetoelectronic devices.[2] In 1939 Verwey[3] found that bulk magnetite undergoes a transition at TV_{V} \approx 120 K from a high temperature "bad metal" conducting phase to a low-temperature insulating phase. He suggested[4] that high temperature conduction is via the fluctuating and correlated valences of the octahedral iron atoms, and that the transition is the onset of charge ordering upon cooling. The Verwey transition mechanism and the question of charge ordering remain highly controversial.[5-11] Here we show that magnetite nanocrystals and single-crystal thin films exhibit an electrically driven phase transition below the Verwey temperature. The signature of this transition is the onset of sharp conductance switching in high electric fields, hysteretic in voltage. We demonstrate that this transition is not due to local heating, but instead is due to the breakdown of the correlated insulating state when driven out of equilibrium by electrical bias. We anticipate that further studies of this newly observed transition and its low-temperature conducting phase will shed light on how charge ordering and vibrational degrees of freedom determine the ground state of this important compound.Comment: 17 pages, 4 figure

    Sport events and human rights: positive promotion or negative erosion?

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    © 2015 Taylor & Francis. In this paper, we build upon recent scholarship on sport event legacies to identify, categorise, and describe the key processes underpinning sport event interactions with human rights (HR). It develops a simple, representative model to illustrate the points where sport events bisect with HR and considers what factors can modify these impacts. The development of this model is based on a meta-review of literature and examination of case studies. It is clear from our analysis that sport events are malleable, symbolic, and political occurrences that can be positioned to provide evidence and support of benefice or harm to the cause of HR. The model also provides a nuanced approach to consider how sport event organisers may begin to think about the tactics and strategies that might be employed, and how they might leverage HR through their sport event. The model also indicates that HR, being similarly malleable political tools, are paradoxical in application in the sport event context and consequently cannot be assumed to be taken-for-granted as event outcomes or outputs

    Pseudohermafroditismo em cão da raça Cocker Spaniel Americano

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    Evaluation of different recall periods for the US National Cancer Institute’s Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE)

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    Aims—The U.S. National Cancer Institute recently developed the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE). PRO-CTCAE is a library of questions for clinical trial participants to self-report symptomatic adverse events (e.g., nausea). The objective of this study is to inform evidence-based selection of a recall period when PRO-CTCAE is included in a trial. We evaluated differences between 1-week, 2-week, 3-week, and 4-week recall periods, using daily reporting as the reference. Methods—English-speaking patients with cancer receiving chemotherapy and/or radiotherapy were enrolled at four U.S. cancer centers and affiliated community clinics. Participants completed 27 PRO-CTCAE items electronically daily for 28 days, and then weekly over 4 weeks, using 1-week, 2-week, 3-week, and 4-week recall periods. For each recall period, mean differences, effect sizes, and intraclass correlation coefficients were calculated to evaluate agreement between the maximum of daily ratings and the corresponding ratings obtained using longer recall periods (e.g., maximum of daily scores over 7 days vs. 1-week recall). Analyses were repeated using the average of daily scores within each recall period rather than the maximum of daily scores. Results—127 subjects completed questionnaires (57% male; median age 57). The median of the 27 mean differences in scores on the PRO-CTCAE 5-point response scale comparing the maximum daily versus the longer recall period (and corresponding effect size), was −0.20 (−0.20) for 1-week recall; −0.36 (−0.31) for 2-week recall; −0.45 (−0.39) for 3-week recall; and −0.47 (−0.40) for 4-week recall. The median intraclass correlation across 27 items between the maximum of daily ratings and the corresponding longer recall ratings for 1-week recall was 0.70 (range: 0.54–0.82); 2-week recall: 0.74 (range: 0.58–0.83); 3-week recall: 0.72 (range: 0.61–0.84); and 4-week recall: 0.72 (range: 0.64–0.86). Similar results were observed for all analyses using the average of daily scores rather than the maximum of daily scores. Conclusions—1-week recall corresponds best to daily reporting. Although intraclass correlations remain stable over time, there are small but progressively larger differences between daily and longer recall periods at 2, 3, and 4 weeks, respectively. The preferred recall period for the PRO-CTCAE is the past 7 days, although investigators may opt for recall periods of 2, 3, or 4 weeks with an understanding that there may be some information loss
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