596 research outputs found

    Intracellular Sources of ROS/H2O2 in Health and Neurodegeneration: Spotlight on Endoplasmic Reticulum.

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    Reactive oxygen species (ROS) are produced continuously throughout the cell as products of various redox reactions. Yet these products function as important signal messengers, acting through oxidation of specific target factors. Whilst excess ROS production has the potential to induce oxidative stress, physiological roles of ROS are supported by a spatiotemporal equilibrium between ROS producers and scavengers such as antioxidative enzymes. In the endoplasmic reticulum (ER), hydrogen peroxide (H2O2), a non-radical ROS, is produced through the process of oxidative folding. Utilisation and dysregulation of H2O2, in particular that generated in the ER, affects not only cellular homeostasis but also the longevity of organisms. ROS dysregulation has been implicated in various pathologies including dementia and other neurodegenerative diseases, sanctioning a field of research that strives to better understand cell-intrinsic ROS production. Here we review the organelle-specific ROS-generating and consuming pathways, providing evidence that the ER is a major contributing source of potentially pathologic ROS

    Microwave-assisted generation and reactivity of aza- and diazafulvenium methides: heterocycles via pericyclic reactions

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    Azafulvenium methides and diazafulvenium methides have been generated under microwave irradiation from 2,2-dioxo-1H,3H-pyrrolo[1,2-c]thiazoles and 2,2-dioxo-1H,3H-pyrazolo[1,5-c]thiazoles, respectively. Pericyclic reactions of these 1,7-dipole intermediates, namely, sigmatropic [1,8]H shifts, 1,7-electrocyclization or [8[pi]+2[pi]] cycloaddition led to the synthesis of a range of pyrrole and pyrazole derivatives. The first evidence for the azafulvenium methides by intermolecular trapping via [8[pi]+2[pi]] cycloaddition is reported.http://www.sciencedirect.com/science/article/B6THS-4SP3SM3-6/1/d6303d9db78919cfe9cd796c1a17d44

    Novel Asymmetric Wittig Reaction: Synthesis of Chiral Allenic Esters

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    Wittig reactions between 10-(phenylsulfonyl)isobornyl (triphenylphosphoranylidene)acetates (1 and 6) and ketenes resulted in asymmetric induction, with the selective synthesis of allenes with axial chirality. Use of the (1R)-(-)-10-(phenylsulfonyl)isoborneol unit allows the synthesis of allenes with S configuration, whereas use of the (1S)-(+)-10-(phenylsulfonyl)isoborneol unit produces allenes with R configuration. The structure of (1R)-(-)-10-(phenylsulfonyl)isobornyl (S)-5,5-dimethylhexa-2,3-dienoate (2e) was determined by X-ray crystallography. Chirooptical studies of the allenic esters were carried out, confirming that two sets of enantiomeric derivatives were obtained. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004

    Clinical presentation and neural correlates of stroke‐associated spatial delusions

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    © 2022 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.Background and purpose: Incongruent beliefs about self-localization in space markedly disturb patients' behavior. Spatial delusions, or reduplicative paramnesias, are characterized by a firm conviction of place reduplication, transformation, or mislocation. Evidence suggests they are frequent after right hemisphere lesions, but comprehensive information about their clinical features is lacking. Methods: We prospectively screened 504 acute right-hemisphere stroke patients for the presence of spatial delusions. Their behavioral and clinical features were systematically assessed. Then, we analyzed the correlation of their duration with the magnitude of structural disruption of belief-associated functional networks. Finally, we described the syndrome subtypes and evaluated whether the clinical categorization would be predicted by the structural disruption of familiarity-associated functional networks using an unsupervised k-means clustering algorithm. Results: Sixty patients with spatial delusions were identified and fully characterized. Most (93%) localized the misidentified places closer to home than the hospital. The median time duration was 3 days (interquartile range = 1-7 days), and it was moderately correlated with the magnitude of structural-functional decoupling of belief-associated functional networks (r = 0.39, p = 0.02; beta coefficient regressing for lesion volume = 3.18, p = 0.04). Each clinical subtype had characteristic response patterns, which were reported, and representative examples were provided. Clustering based on structural disruption of familiarity- and unfamiliarity-associated functional networks poorly matched the clinical categorization (lesion: Rand index = 0.47; structural disconnection: Rand index = 0.51). Conclusions: The systematic characterization of the peculiar clinical features of stroke-associated spatial delusions may improve the syndrome diagnosis and clinical approaches. The novel evidence about their neural correlates fosters the clarification of the pathophysiology of delusional misidentifications.This work was supported by the following grants: PRÉMIO JOÃO LOBO ANTUNES 2018–SCML and Bolsa de Investigação em Doenças Vasculares Cerebrais 2017–SPAVC.info:eu-repo/semantics/publishedVersio

    Avaliação da afasia: impacto do material no desempenho da nomeação

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    Background: Naming and lexical retrieval difficulties are common symptoms of aphasia. Naming abilities are usually evaluated by means of real objects or pictures or line drawings that are printed. Objective: The aim of this study was to investigate whether the ability to name objects among individuals with aphasia is influenced by the dimensions of the visual stimuli and to understand whether the order of presentation of the stimuli, number of years of education and length of time post-onset are involved in the success of naming. Methods: The naming abilities of healthy controls and patients with acute or chronic aphasia due to stroke were assessed through presentation of two sets of 24 stimuli consisting of real objects and color photographs of the same objects presented on a screen. The results obtained under these two conditions were compared by means of within-subject paired ANOVA, controlling for presentation order. Results: 40 patients (62.4 ± 17.3 years old; 70% females; mean education level of 8.5 ± 5.3 years; and 60% evaluated within the first eight days after stroke) and 50 controls that were age, gender and education-matched were included. Object naming was significantly better than naming color photographs among the patients (p = 0.001), but no differences were observed among the controls. Age, education, length of time postonset and presentation sequence did not have any impact on naming performance. Conclusion: These results suggest that use of digital color photographs for naming objects in assessment of aphasia may be associated with lower naming performance, compared with use of real objects. This needs to be taken into account when different forms of stimuli are presented in sequential aphasia evaluations.info:eu-repo/semantics/publishedVersio

    Eficiência da fosfina no controle da broca da raiz do cajueiro, Marshallius bondari Rosado Neto, 1989 (Col., Curculionidae).

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    Eficiencia da fosfina no controle da broca da raiz do cajueiro.bitstream/CNPAT-2010/1840/1/Pa-015.pd

    Controle químico da broca do tronco do cajueiro, Marshallius anacardii Lima, 1979 (Col., Curculionidae)

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    Controle quimico da broca do tronco do cajueiro.bitstream/CNPAT-2010/1851/1/Pa-013.pd

    New chemistry of diazafulvenium methides: one way to pyrazoles

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    Diazafulvenium methides generated from the solution pyrolysis of pyrazolo[1,5-c][1,3]thiazole-2,2-dioxides participate in [8[pi]+2[pi]] cycloadditions giving pyrazolo[1,5-a]pyridine derivatives. 1-Methyl-diazafulvenium, generated under flash vacuum pyrolysis reaction conditions, undergoes an intramolecular sigmatropic [1,8]H shift giving 1-vinyl-1H-pyrazoles.http://www.sciencedirect.com/science/article/B6THS-4HR7298-7/1/af0dd8d679e7977f53bc0d4af9a5b68
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