University of Coimbra

About: University of Coimbra is a education organization based out in Coimbra, Portugal. It is known for research contribution in the topics: Population & Context (language use). The organization has 14318 authors who have published 43067 publications receiving 994733 citations. The organization is also known as: UC & Universidade dos Estudos Gerais.

Sustained effects of nonallele-specific Huntingtin silencing†

Abstract: Objective: Huntington's disease (HD) is a fatal autosomal dominant neurodegenerative disorder caused by a polyglutamine expansion in the huntingtin (htt) protein. No cure is available to date to alleviate neurodegeneration. Recent studies have demonstrated that RNA interference represents a promising approach for the treatment of autosomal dominant disorders. But whether an allele-specific silencing of mutant htt or a nonallele-specific silencing should be considered has not been addressed.

Validation of the Psychometric Properties of the Self-Compassion Scale. Testing the Factorial Validity and Factorial Invariance of the Measure among Borderline Personality Disorder, Anxiety Disorder, Eating Disorder and General Populations

Abstract: Background During the last years, there has been a growing interest in self-compassion Empirical evidences show that self-compassion is associated with psychological benefits among young adults and it might be considered a buffer factor in several mental disorders Aims The aim of this study was to validate the psychometric properties of the Self-compassion Scale (SCS: Neff, 2003a) after the initial lack of replicating the original six-factor structure Method Data were collected from the overall database of a research centre (56 men and 305 women; mean age = 2519) and comprised four groups: borderline personality disorder, anxiety disorder, eating disorder and general population Results Confirmatory factor analysis supported a two-factor model (self-compassionate attitude versus self-critical attitude) with good internal consistencies, construct-related validity and external validity Configural, weak measurement and structural invariance of the two-factor model of SCS were also shown Conclusions Findings support the generalizability of the two-factor model and show that both properties and interpretations of scores on self-compassion are equivalent across these population groups Copyright © 2015 John Wiley & Sons, Ltd Key Practitioner Message A two-factor structure of SCS with strong psychometric validity was supported in clinical and non-clinical samples Helping individuals with limited experiences of compassion to develop positive internal processing systems seems to be related with better mental health, self-acceptance and self-nurturing abilities The non-probabilistic sampling limits the generalization of our conclusions

Dual Presynaptic Control by ATP of Glutamate Release via Facilitatory P2X1, P2X2/3, and P2X3 and Inhibitory P2Y1, P2Y2, and/or P2Y4 Receptors in the Rat Hippocampus

Abstract: ATP is released in a vesicular manner from nerve terminals mainly at higher stimulation frequencies. There is a robust expression of ATP (P2) receptors in the brain, but their role is primarily unknown. We report that ATP analogs biphasically modulate the evoked release of glutamate from purified nerve terminals of the rat hippocampus, the facilitation being mediated by P2X 1 , P2X 2/3 , and P2X 3 [antagonized by 8-(benzamido)naphthalene-1,3,5-trisulfonate and 2′,3′- O -(2,4,6-trinitrophenyl)-ATP] and the inhibition by P2Y 1, P2Y 2 , and/or P2Y 4 [antagonized by reactive blue 2 and 2′deoxy- N 6 -methyladenosine-3′,5′-bisphosphate and mimicked by P1-(urinine 5′-),P4-(inosine 5′-) tetraphosphate and 2-methylthio-ADP] receptors. The combination of single-cell PCR analysis of rat hippocampal pyramidal neurons, Western blot analysis of purified presynaptic active zone fraction, and immunocytochemical analysis of hippocampal glutamatergic terminals revealed that the P2 receptors expressed in glutamatergic neurons, located in the active zone and in glutamatergic terminals, were precisely P2X 1, P2X 2 , and P2X 3 subunits and P2Y 1, P2Y 2 , and P2Y 4 receptors. This provides coincident functional and molecular evidence that P2 receptors are present and act presynaptically as a modulatory system controlling hippocampal glutamate release.

Modulator effects of interleukin-1beta and tumor necrosis factor-alpha on AMPA-induced excitotoxicity in mouse organotypic hippocampal slice cultures.

Abstract: The inflammatory cytokines interleukin-1β and tumor necrosis factor-α (TNF-α) have been identified as mediators of several forms of neurodegeneration in the brain. However, they can produce either deleterious or beneficial effects on neuronal function. We investigated the effects of these cytokines on neuronal death caused by exposure of mouse organotypic hippocampal slice cultures to toxic concentrations of AMPA. Either potentiation of excitotoxicity or neuroprotection was observed, depending on the concentration of the cytokines and the timing of exposure. A relatively high concentration of mouse recombinant TNF-α (10 ng/ml) enhanced excitotoxicity when the cultures were simultaneously exposed to AMPA and to this cytokine. Decreasing the concentration of TNF-α to 1 ng/ml resulted in neuroprotection against AMPA-induced neuronal death independently on the application protocol. By using TNF-α receptor (TNFR) knock-out mice, we demonstrated that the potentiation of AMPA-induced toxicity by TNF-α involves TNF receptor-1, whereas the neuroprotective effect is mediated by TNF receptor-2. AMPA exposure was associated with activation and proliferation of microglia as assessed by macrophage antigen-1 and bromodeoxyuridine immunohistochemistry, suggesting a functional recruitment of cytokine-producing cells at sites of neurodegeneration. Together, these findings are relevant for understanding the role of proinflammatory cytokines and microglia activation in acute and chronic excitotoxic conditions.

Photoacoustic Measurements of Porphyrin Triplet-State Quantum Yields and Singlet-Oxygen Efficiencies

Abstract: Photoacoustic calorimetry was used to measure the quantum yields of singlet molecular oxygen production by the triplet states of tetraphenylporphyrin (TPP), ZnTPP and CuTPP in toluene, yielding values of 0.67 0.14, 0.68 0.19 and 0.03 0.01, respectively. We show that a novel dichlorophenyl derivative of ZnTPP is capable of singlet-oxygen production with a 0.90 0.07 quantum yield. The synthesis and characterisation of a new photostable chlorin with high absorptivity in the red that is capable of singlet-oxygen production with 0.54 0.06 quantum yield is described. Our results suggest that chlorinated chlorins may be interesting new sensitisers for photodynamic therapy.