1,244 research outputs found

    Remission of severe restless legs syndrome and periodic limb movements in sleep after bilateral excision of multiple foot neuromas: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Restless legs syndrome is a sensorimotor neurological disorder characterized by an urge to move the legs in response to uncomfortable leg sensations. While asleep, 70 to 90 percent of patients with restless legs syndrome have periodic limb movements in sleep. Frequent periodic limb movements in sleep and related brain arousals as documented by polysomnography are associated with poorer quality of sleep and daytime fatigue. Restless legs syndrome in middle age is sometimes associated with neuropathic foot dysesthesias. The causes of restless legs syndrome and periodic limb movements in sleep are unknown, but the sensorimotor symptoms are hypothesized to originate in the central nervous system. We have previously determined that bilateral forefoot digital nerve impingement masses (neuromas) may be a cause of both neuropathic foot dysesthesias and the leg restlessness of restless legs syndrome. To the best of our knowledge, this case is the first report of bilateral foot neuromas as a cause of periodic limb movements in sleep.</p> <p>Case presentation</p> <p>A 42-year-old Caucasian woman with severe restless legs syndrome and periodic limb movements in sleep and bilateral neuropathic foot dysesthesias was diagnosed as having neuromas in the second, third, and fourth metatarsal head interspaces of both feet. The third interspace neuromas represented regrowth (or 'stump') neuromas that had developed since bilateral third interspace neuroma excision five years earlier. Because intensive conservative treatments including repeated neuroma injections and various restless legs syndrome medications had failed, radical surgery was recommended. All six neuromas were excised. Leg restlessness, foot dysesthesias and subjective sleep quality improved immediately. Assessment after 18 days showed an 84 to 100 percent reduction of visual analog scale scores for specific dysesthesias and marked reductions of pre-operative scores of the Pittsburgh sleep quality index, fatigue severity scale, and the international restless legs syndrome rating scale (36 to 4). Polysomnography six weeks post-operatively showed improved sleep efficiency, a marked increase in rapid eye movement sleep, and marked reductions in hourly rates of both periodic limb movements in sleep with arousal (135.3 to 3.3) and spontaneous arousals (17.3 to 0).</p> <p>Conclusion</p> <p>The immediate and near complete remission of symptoms, the histopathology of the excised tissues, and the marked improvement in polysomnographic parameters documented six weeks after surgery together indicate that this patient's severe restless legs syndrome and periodic limb movements in sleep was of peripheral nerve (foot neuroma) origin. Further study of foot neuromas as a source of periodic limb movements in sleep and as a cause of sleep dysfunction in patients with or without concomitant restless legs syndrome, is warranted.</p

    Evidence for a dissociation between the control of oculomotor capture and disengagement

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    The current study investigated whether capture of the eyes by a salient onset distractor and the disengagement of the eyes from that distractor are driven by the same or by different underlying control modes. A variant of the classic oculomotor capture task was used. Observers had to make a saccade to the only gray circle among red background circles. On some trials, a green (novel color), red (placeholder color) or gray (target color) distractor square was presented with sudden onset. Results showed that when participants reacted fast, oculomotor capture was primarily driven by bottom-up pop-out: both types of distractors (green and gray) that popped out among the red background elements showed more capture than a red distractor that did not pop-out. In contrast to initial capture, disengagement of the eyes from the distractor was driven by top-down target–distractor similarity effects. We also examined the time-course of this effect. The distractor could change from green to either the target or placeholder color. When the color change was early in time (30–40 ms after its onset), dwell times were strongly affected by the change, whereas the effect on oculomotor capture was weak. Importantly, a change occurring as early as 60–80 ms after distractor onset did neither affect capture nor dwell times, corroborating the assumption of parallel programming of saccades

    Recurrent Modification of a Conserved Cis-Regulatory Element Underlies Fruit Fly Pigmentation Diversity

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    The development of morphological traits occurs through the collective action of networks of genes connected at the level of gene expression. As any node in a network may be a target of evolutionary change, the recurrent targeting of the same node would indicate that the path of evolution is biased for the relevant trait and network. Although examples of parallel evolution have implicated recurrent modification of the same gene and cis-regulatory element (CRE), little is known about the mutational and molecular paths of parallel CRE evolution. In Drosophila melanogaster fruit flies, the Bric-à-brac (Bab) transcription factors control the development of a suite of sexually dimorphic traits on the posterior abdomen. Female-specific Bab expression is regulated by the dimorphic element, a CRE that possesses direct inputs from body plan (ABD-B) and sex-determination (DSX) transcription factors. Here, we find that the recurrent evolutionary modification of this CRE underlies both intraspecific and interspecific variation in female pigmentation in the melanogaster species group. By reconstructing the sequence and regulatory activity of the ancestral Drosophila melanogaster dimorphic element, we demonstrate that a handful of mutations were sufficient to create independent CRE alleles with differing activities. Moreover, intraspecific and interspecific dimorphic element evolution proceeded with little to no alterations to the known body plan and sex-determination regulatory linkages. Collectively, our findings represent an example where the paths of evolution appear biased to a specific CRE, and drastic changes in function were accompanied by deep conservation of key regulatory linkages. © 2013 Rogers et al

    Multiple signalling modalities mediated by dendritic exocytosis of oxytocin and vasopressin

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    The mammalian hypothalamic magnocellular neurons of the supraoptic and paraventricular nuclei are among the best understood of all peptidergic neurons. Through their anatomical features, vasopressin- and oxytocin-containing neurons have revealed many important aspects of dendritic functions. Here, we review our understanding of the mechanisms of somato-dendritic peptide release, and the effects of autocrine, paracrine and hormone-like signalling on neuronal networks and behaviour

    Effects of external nutrient sources and extreme weather events on the nutrient budget of a Southern European coastal lagoon

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    The seasonal and annual nitrogen (N), phosphorus (P), and carbon (C) budgets of the mesotidal Ria Formosa lagoon, southern Portugal, were estimated to reveal the main inputs and outputs, the seasonal patterns, and how they may influence the ecological functioning of the system. The effects of extreme weather events such as long-lasting strong winds causing upwelling and strong rainfall were assessed. External nutrient inputs were quantified; ocean exchange was assessed in 24-h sampling campaigns, and final calculations were made using a hydrodynamic model of the lagoon. Rain and stream inputs were the main freshwater sources to the lagoon. However, wastewater treatment plant and groundwater discharges dominated nutrient input, together accounting for 98, 96, and 88 % of total C, N, and P input, respectively. Organic matter and nutrients were continuously exported to the ocean. This pattern was reversed following extreme events, such as strong winds in early summer that caused upwelling and after a period of heavy rainfall in late autumn. A principal component analysis (PCA) revealed that ammonium and organic N and C exchange were positively associated with temperature as opposed to pH and nitrate. These variables reflected mostly the benthic lagoon metabolism, whereas particulate P exchange was correlated to Chl a, indicating that this was more related to phytoplankton dynamics. The increase of stochastic events, as expected in climate change scenarios, may have strong effects on the ecological functioning of coastal lagoons, altering the C and nutrient budgets.Portuguese Science and Technology Foundation (FCT) [POCI/MAR/58427/2004, PPCDT/MAR/58427/2004]; Portuguese Science and Technology Foundation (FCT

    Object Detection Through Exploration With A Foveated Visual Field

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    We present a foveated object detector (FOD) as a biologically-inspired alternative to the sliding window (SW) approach which is the dominant method of search in computer vision object detection. Similar to the human visual system, the FOD has higher resolution at the fovea and lower resolution at the visual periphery. Consequently, more computational resources are allocated at the fovea and relatively fewer at the periphery. The FOD processes the entire scene, uses retino-specific object detection classifiers to guide eye movements, aligns its fovea with regions of interest in the input image and integrates observations across multiple fixations. Our approach combines modern object detectors from computer vision with a recent model of peripheral pooling regions found at the V1 layer of the human visual system. We assessed various eye movement strategies on the PASCAL VOC 2007 dataset and show that the FOD performs on par with the SW detector while bringing significant computational cost savings.Comment: An extended version of this manuscript was published in PLOS Computational Biology (October 2017) at https://doi.org/10.1371/journal.pcbi.100574

    Clinical review: Practical recommendations on the management of perioperative heart failure in cardiac surgery

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    Acute cardiovascular dysfunction occurs perioperatively in more than 20% of cardiosurgical patients, yet current acute heart failure (HF) classification is not applicable to this period. Indicators of major perioperative risk include unstable coronary syndromes, decompensated HF, significant arrhythmias and valvular disease. Clinical risk factors include history of heart disease, compensated HF, cerebrovascular disease, presence of diabetes mellitus, renal insufficiency and high-risk surgery. EuroSCORE reliably predicts perioperative cardiovascular alteration in patients aged less than 80 years. Preoperative B-type natriuretic peptide level is an additional risk stratification factor. Aggressively preserving heart function during cardiosurgery is a major goal. Volatile anaesthetics and levosimendan seem to be promising cardioprotective agents, but large trials are still needed to assess the best cardioprotective agent(s) and optimal protocol(s). The aim of monitoring is early detection and assessment of mechanisms of perioperative cardiovascular dysfunction. Ideally, volume status should be assessed by 'dynamic' measurement of haemodynamic parameters. Assess heart function first by echocardiography, then using a pulmonary artery catheter (especially in right heart dysfunction). If volaemia and heart function are in the normal range, cardiovascular dysfunction is very likely related to vascular dysfunction. In treating myocardial dysfunction, consider the following options, either alone or in combination: low-to-moderate doses of dobutamine and epinephrine, milrinone or levosimendan. In vasoplegia-induced hypotension, use norepinephrine to maintain adequate perfusion pressure. Exclude hypovolaemia in patients under vasopressors, through repeated volume assessments. Optimal perioperative use of inotropes/vasopressors in cardiosurgery remains controversial, and further large multinational studies are needed. Cardiosurgical perioperative classification of cardiac impairment should be based on time of occurrence (precardiotomy, failure to wean, postcardiotomy) and haemodynamic severity of the patient's condition (crash and burn, deteriorating fast, stable but inotrope dependent). In heart dysfunction with suspected coronary hypoperfusion, an intra-aortic balloon pump is highly recommended. A ventricular assist device should be considered before end organ dysfunction becomes evident. Extra-corporeal membrane oxygenation is an elegant solution as a bridge to recovery and/or decision making. This paper offers practical recommendations for management of perioperative HF in cardiosurgery based on European experts' opinion. It also emphasizes the need for large surveys and studies to assess the optimal way to manage perioperative HF in cardiac surgery
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