1,746 research outputs found

    Spinal cord toxoplasmosis as an unusual presentation of AIDS: case report and review of the literature

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    Approximately 10% of patients with AIDS present with some neurological deficit as their initial complaint, and up to 80% will have CNS involvement during the course of their disease. Toxoplasmosis is the most common cause of cerebral mass lesions in patients with AIDS, but appears to be an uncommon cause of spinal cord disease. The incidence of myelopathy may be as high as 20%, with 50% of the cases reported post-mortem. We present a unique case of spinal cord disease as the initial presentation of AIDS. We also present a comprehensive literature review of this topic, its diagnosis and treatment. This is a retrospective chart review case report. After a detailed case presentation, several diagnostic and therapeutic aspects of this unique case are thoroughly discussed. Although spinal cord toxoplasmosis is uncommon, it has been suggested that most patients with AIDS that present with evolving myelopathy, characterized by extremity weakness, sensory involvement, spinal cord enlargement, enhancing lesions in brain or spinal cord CT or MRI, have toxoplasmic myelitis

    Characterization of the Adherence of Clostridium difficile Spores: The Integrity of the Outermost Layer Affects Adherence Properties of Spores of the Epidemic Strain R20291 to Components of the Intestinal Mucosa

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    IndexaciĂłn: Web of Science.Clostridium difficile is the causative agent of the most frequently reported nosocomial diarrhea worldwide. The high incidence of recurrent infection is the main clinical challenge of C. difficile infections (CBI). Formation of C. difficile spores of the epidemic strain R20291 has been shown to be essential for recurrent infection and transmission of the disease in a mouse model. However, the underlying mechanisms of how these spores persist in the colonic environment remains unclear. In this work, we characterized the adherence properties of epidemic R20291 spores to components of the intestinal mucosa, and we assessed the role of the exosporium integrity in the adherence properties by using cdeC mutant spores with a defective exosporium layer. Our results showed that spores and vegetative cells of the epidemic R20291 strain adhered at high levels to monolayers of Caco-2 cells and mucin. Transmission electron micrographs of Caco-2 cells demonstrated that the hair-like projections on the surface of R20291 spores are in close proximity with the plasma membrane and microvilli of undifferentiated and differentiated monolayers of Caco-2 cells. Competitive-binding assay in differentiated Caco-2 cells suggests that spore-adherence is mediated by specific binding sites. By using spores of a cdeC mutant we demonstrated that the integrity of the exosporium layer determines the affinity of adherence of C. difficile spores to Caco-2 cells and mucin. Binding of fibronectin and vitronectin to the spore surface was concentration-dependent, and depending on the concentration, spore-adherence to Caco-2 cells was enhanced. In the presence of an aberrantly-assembled exosporium (cdeC spores), binding of fibronectin, but not vitronectin, was increased. Notably, independent of the exosporium integrity, only a fraction of the spores had fibronectin and vitronectin molecules binding to their surface. Collectively, these results demonstrate that the integrity of the exosporium layer of strain R20291 contributes to selective spore adherence to components of the intestinal mucosa.http://journal.frontiersin.org/article/10.3389/fcimb.2016.00099/ful

    Frontal lobe disfunction in children and adolescents with temporal lobe epilepsy and possible correlation with psychiatric disorders

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    Introduction: There is evidence that individuals with certain types of epilepsy may present cognitive disorders, and that these disorders can be more debilitating than seizures proper. Frontal lobe disorders are reported in adults with temporal lobe epilepsy, carachterized by executive disfunction. Rationale: Literary revision of work concerning the occurence of frontal lobe dysfunction in children and adolescents with temporal lobe epilepsy. Methods: Systematic revision of published literature in PUBMED. Results: Frontal lobe dysfunction has been poorly studied in children with epilepsy, especially in temporal lobe epilepsy. In the only study on the subject, executive deficit was demonstrated. Moreover, children with mesial sclerosis had more deficit in execution/planning than those with frontal or temporal neocortical lesions. Presence of frontal lobe dysfunction, in patients with partial and generalized epilepsy, may corroborate evidence that epilepsy and psychiatric disorders are epiphenomena and not cause effect related phenomena. Conclusion: There are few articles on frontal lobe dysfunction in children with temporal lobe epilepsy. It would be interesting to find out if, and how much this occurs, and if patients with distinct etiologies present different levels of functional disability.Introdução: HĂĄ evidĂȘncias de que pessoas com alguns tipos de epilepsia podem apresentar prejuĂ­zos cognitivos, sendo que para alguns pacientes, tais dĂ©ficits cognitivos podem ser mais debilitantes do que suas crises epilĂ©pticas. A disfunção do lobo frontal Ă© relatada em adultos com epilepsia do lobo temporal, caracte­rizada pela disfunção executiva. Objetivo: Rever a literatura sobre a ocorrĂȘncia de disfunção de lobo frontal em crianças e adolescentes com epilepsia do lobo temporal. MĂ©todos: RevisĂŁo sistemĂĄtica da literatura compulsada no PUBMED. Resultados: A disfunção do lobo frontal tem sido pouco estudada em crianças com epilepsia, em especial com epilepsia do lobo temporal. No Ășnico estudo sobre este assunto, demonstrou­se que hĂĄ um dĂ©ficit executivo, sendo que as crianças com esclerose mesial tĂȘm maiores dĂ©ficits de execução/ planejamento do que aquelas com lesĂ”es neocorticais temporais ou frontais. A presença de uma disfunção do lobo frontal nos pacientes com epilepsia parcial e generalizada pode corroborar as evidĂȘncias de que epilepsia e transtorno psiquiĂĄtrico sĂŁo epifenĂŽmenos e nĂŁo fenĂŽmenos com relação causa efeito. Conclu­sĂ”es: HĂĄ uma escassez de artigos sobre a disfunção do lobo frontal em crianças com epilepsia do lobo tempo­ral, sendo de interesse saber se esta ocorre e se pacientes com etiologias distintas apresentam diferentes graus de comprometimento destas funçÔes.13113

    Controlling photocatalytic activity by self-assembly – Tuning perylene bisimide photocatalysts for the hydrogen evolution reaction

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    Amino acid functionalized perylene bisimides (PBIs) form self-assembled structures in solution, the nature of which depends on the local environment. Using a high-throughput photocatalysis setup, five PBIs are studied for the hydrogen evolution reaction (HER) under a range of conditions (pH and hole scavenger concentration) across 350 experiments to explore the relationship between supramolecular structure and photocatalytic activity. Using small angle X-ray scattering (SAXS), NMR spectroscopy and ultraviolet-visible (UV-vis) absorption spectroscopy, it is shown that photocatalytic activity is determined by the nature of the self-assembled aggregate that is formed, demonstrating the potential of self-assembly to tune activity. There is a clear correlation between the presence of charged flexible cylindrical aggregates and the occurrence of photocatalytic H2 production, with UV–vis spectroscopy indicating that the most active structure type has a distinctive form of π-aggregation which is proposed to enable efficient charge separation across multiple PBI units

    Perspectives on conservation impacts of the global primate trade

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    MFH and DRKN are grateful to Animal Protection Denmark and MFH to the Carlsberg Foundation (grant number CF21-0473). AMM thanks the Whitley Fund for Nature, The Rufford Small Grants, The International Primate Protection League, and Mr. Martin Stanley for their long-term financial support toward night monkey conservation.The global trade in nonhuman primates represents a substantial threat to ecosystem health, human health, and primate conservation worldwide. Most of the primate trade involves trade for pet-keeping, consumption, or biomedical experimentation. We present an overview of international primate trade through five case studies; each describes a different facet of this trade. We draw on published scientific literature, media outlets, and open access datasets, including the CITES Trade Database to build these case studies. Case study 1 describes the role of introduced island populations of Macaca and Chlorocebus in trade for biomedical experimentation; case study 2 covers the global health threats posed by the primate trade, including zoonotic disease transmission once animals enter the trade pipeline; case study 3 addresses the ways that changing patterns of primate trade, from local markets to online, have increased the demand for primates as pets; case study 4 recognizes the role that local environmental activism can play in mitigating trade; and case study 5 shows variation between global regions in their contribution to the primate trade. We recommend greater oversight of primate trade, especially domestic trade within primate range countries, and real-time reporting to CITES to accurately track primate trade. Effective conservation-focused regulations that can minimise the negative effects of primate trade must be tailored to specific regions and species and require transparency, careful regulation, field research, and an understanding of the magnitude of this trade.Peer reviewe

    Differences Between High vs. Low Performance Chess Players in Heart Rate Variability During Chess Problems

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    Background: Heart rate variability (HRV) has been considered as a measure of heart-brain interaction and autonomic modulation, and it is modified by cognitive and attentional tasks. In cognitive tasks, HRV was reduced in participants who achieved worse results. This could indicate the possibility of HRV predicting cognitive performance, but this association is still unclear in a high cognitive load sport such as chess.Objective: To analyze modifications on HRV and subjective perception of stress, difficulty and complexity in different chess problem tasks.Design: HRV was assessed at baseline. During the chess problems, HRV was also monitored, and immediately after chess problems the subjective stress, difficulty and complexity were also registered.Methods: A total of 16 male chess players, age: 35.19 (13.44) and ELO: 1927.69 (167.78) were analyzed while six chess problem solving tasks with different level of difficulty were conducted (two low level, two medium level and two high level chess problems). Participants were classified according to their results into two groups: high performance or low performance.Results: Friedman test showed a significant effect of tasks in HRV indexes and perceived difficulty, stress and complexity in both high and low performance groups. A decrease in HRV was observed in both groups when chess problems difficulty increased. In addition, HRV was significantly higher in the high performance group than in the low performance group during chess problems.Conclusion: An increase in autonomic modulation was observed to meet the cognitive demands of the problems, being higher while the difficulty of the tasks increased. Non-linear HRV indexes seem to be more reactive to tasks difficulty, being an interesting and useful tool in chess training

    Myt1l safeguards neuronal identity by actively repressing many non-neuronal fates

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    Normal differentiation and induced reprogramming require the activation of target cell programs and silencing of donor cell programs(1,2). In reprogramming, the same factors are often used to reprogram many different donor cell types3. As most developmental repressors, such as RE1-silencing transcription factor (REST) and Groucho (also known as TLE), are considered lineage-specific repressors(4,5), it remains unclear how identical combinations of transcription factors can silence so many different donor programs. Distinct lineage repressors would have to be induced in different donor cell types. Here, by studying the reprogramming of mouse fibroblasts to neurons, we found that the pan neuron-specific transcription factor Myt1-like (Myt1l)(6) exerts its pro-neuronal function by direct repression of many different somatic lineage programs except the neuronal program. The repressive function of Myt1l is mediated via recruitment of a complex containing Sin3b by binding to a previously uncharacterized N-terminal domain. In agreement with its repressive function, the genomic binding sites of Myt1l are similar in neurons and fibroblasts and are preferentially in an open chromatin configuration. The Notch signalling pathway is repressed by Myt1l through silencing of several members, including Hes1. Acute knockdown of Myt1l in the developing mouse brain mimicked a Notch gain-of-function phenotype, suggesting that Myt1l allows newborn neurons to escape Notch activation during normal development. Depletion of Myt1l in primary postmitotic neurons de-repressed non-neuronal programs and impaired neuronal gene expression and function, indicating that many somatic lineage programs are actively and persistently repressed by Myt1l to maintain neuronal identity. It is now tempting to speculate that similar 'many-but-one' lineage repressors exist for other cell fates; such repressors, in combination with lineage-specific activators, would be prime candidates for use in reprogramming additional cell types.Non peer reviewe

    Enantiopure 4‐oxazolin‐2‐ones and 4‐methylene‐2‐oxazolidinones as chiral building blocks in a divergent asymmetric synthesis of heterocycles

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    En este trabajo se describe la reactividad de las oxazolidin-2-onas en un ambiente quiral obteniĂ©ndose resultados novedosos, los cuales se describen extensamente.Enantiopure 3‐((R)‐ and 3‐((S)‐1‐phenylethyl)‐4‐oxazoline‐2‐ones were evaluated as chiral building blocks for the divergent construction of heterocycles with stereogenic quaternary centers. The N‐(R)‐ or N‐(S)‐1‐phenylethyl group of these compounds proved to be an efficient chiral auxiliary for the asymmetric induction of the 4‐ and 5‐positions of the 4‐oxazolin‐2‐one ring through thermal and MW‐promoted nucleophilic conjugated addition to Michael acceptors and alkyl halides. The resulting adducts were transformed via a cascade process into fused six‐membered carbo‐ and heterocycles. The structure of the reaction products depended on the electrophiles and reaction conditions used. Alternative isomeric 4‐methylene‐2‐oxazolidinones served as chiral precursors for a versatile and divergent approach to highly substituted cyclic carbamates. DFT quantum calculations showed that the formation of bicyclic pyranyl compounds was generated by a diastereoselective concerted hetero‐Diels‐Alder cycloaddition.Instituto PolitĂ©cnico Nacional, Secretaria de InvestigaciĂłn y Estudios Avanzados de la Universidad AutĂłnoma del Estado de MĂ©xico, Universidad de Guanajuato y CONACYT

    The OECD and phases in the international political economy, 1961–2011

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    In 2011, the OECD turned fifty. To provide a broad foundation for further thinking on this organization, we analyse its evolution over half a century from two perspectives: phases in the international political economy and the literature on IPE. By so doing, we uncover two paradoxes. Firstly, we find that the organization’s evolution closely mirrored major phases in the postwar international political economy until recently. However, the OECD’s long-term dependence on theWest has now become an obstacle to its efforts to adapt to the latest phase, characterised by the rise of non-Western powers. Secondly, we show that, during the OECD’s “golden age”, scholars paid relatively little attention to the organization but, from the 2000s, as the organization faced an unprecedented challenge of its potential economic decline, IPE literature on the organization blossomed
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