Recursos de colección

Estudo Geral - Universidade de Coimbra (19.630 recursos)

ESTUDO GERAL é a designação do repositório digital da produção científica da Universidade de Coimbra, com o objectivo de divulgar conteúdos digitais de natureza científica de autores ligados à Universidade de Coimbra. A sua criação insere-se no movimento de Acesso Livre à Literatura científica (Open Access), ao qual o Conselho de Reitores das Universidades Portuguesas aderiu em 2006 e que a Universidade de Coimbra subscreveu. À semelhança de outras grandes universidades nacionais e internacionais, a UC tem o maior interesse em aumentar a sua presença na rede informática mundial, sendo cada vez mais - e também por essa via - um emissor de conhecimento e cultura.

I&D CNC - Artigos em Revistas Internacionais

Mostrando recursos 1 - 20 de 29

  1. Acute effects of cocaine, morphine and their combination on bioenergetic function and susceptibility to oxidative stress of rat liver mitochondria

    Cunha-Oliveira, Teresa; Silva, Lisbeth; Silva, Ana Maria; Moreno, António J.; Oliveira, Catarina R.; Santos, Maria S.

  2. Mitochondrial complex I dysfunction induced by cocaine and cocaine plus morphine in brain and liver mitochondria

    Cunha-Oliveira, Teresa; Silva, Lisbeth; Silva, Ana Maria; Moreno, António J.; Oliveira, Catarina R.; Santos, Maria S.
    Mitochondrial function and energy metabolism are affected in brains of human cocaine abusers. Cocaine is known to induce mitochondrial dysfunction in cardiac and hepatic tissues, but its effects on brain bioenergetics are less documented. Furthermore, the combination of cocaine and opioids (speedball) was also shown to induce mitochondrial dysfunction. In this work, we compared the effects of cocaine and/or morphine on the bioenergetics of isolated brain and liver mitochondria, to understand their specific effects in each tissue. Upon energization with complex I substrates, cocaine decreased state-3 respiration in brain (but not in liver) mitochondria and decreased uncoupled respiration and mitochondrial...

  3. Dissecting Regulatory Networks of Filopodia Formation in a Drosophila Growth Cone Model

    Gonçalves-Pimentel, Catarina; Gombos, Rita; Mihály, József; Sánchez-Soriano, Natalia; Prokop, Andreas
    F-actin networks are important structural determinants of cell shape and morphogenesis. They are regulated through a number of actin-binding proteins. The function of many of these proteins is well understood, but very little is known about how they cooperate and integrate their activities in cellular contexts. Here, we have focussed on the cellular roles of actin regulators in controlling filopodial dynamics. Filopodia are needle-shaped, actin-driven cell protrusions with characteristic features that are well conserved amongst vertebrates and invertebrates. However, existing models of filopodia formation are still incomplete and controversial, pieced together from a wide range of different organisms and cell...

  4. Cdk5: Multitasking between physiological and pathological conditions

    Lopes, João P.; Agostinho, Paula
    Cyclin-dependent kinase 5 (Cdk5) is a peculiar proline-directed serine/threonine kinase. Unlike the other members of the Cdk family, Cdk5 is not directly involved in cell cycle regulation, being normally associated with neuronal processes such as migration, cortical layering and synaptic plasticity. This kinase is present mainly in post-mitotic neurons and its activity is tightly regulated by the interaction with the specific activators, p35 and p39. Despite its pivotal role in CNS development, Cdk5 dysregulation has been implicated in different pathologies, such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD) and, most recently, prion-related encephalopathies (PRE). In these neurodegenerative...

  5. Expression and function of the insulin receptor in normal and osteoarthritic human chondrocytes: modulation of anabolic gene expression, glucose transport and GLUT-1 content by insulin

    Rosa, S. C.; Rufino, A. T.; Judas, F.; Tenreiro, C.; Lopes, M. C.; Mendes, A. F.
    Objective Chondrocytes respond to insulin, but the presence and role of the specific high affinity insulin receptor (InsR) has never been demonstrated. This study determined whether human chondrocytes express the InsR and compared its abundance and function in normal and osteoarthritis (OA) human chondrocytes. Design Cartilage sections were immunostained for detection of the InsR. Non-proliferating chondrocyte cultures from normal and OA human cartilage were treated with 1 nM or 10 nM insulin for various periods. InsR, insulin-like growth factor receptor (IGFR), aggrecan and collagen II mRNA levels were assessed by real time RT-PCR. InsR, glucose transporter (GLUT)-1, phospho-InsRbeta and phospho-Akt were evaluated by...

  6. Diabetes induces early transient changes in the content of vesicular transporters and no major effects in neurotransmitter release in hippocampus and retina

    Baptista, Filipa I.; Gaspar, Joana M.; Cristóvão, Armando; Santos, Paulo F.; Köfalvi, Attila; Ambrósio, António F.
    Diabetes induces changes in neurotransmitter release in central nervous system, which depend on the type of neurotransmitter and region studied. In this study, we evaluated the effect of diabetes (two and eight weeks duration) on basal and evoked release of [14C]glutamate and [3H]GABA in hippocampal and retinal synaptosomes. We also analyzed the effect of diabetes on the protein content of vesicular glutamate and GABA transporters, VGluT-1, VGluT-2 and VGAT, and on the α1A subunit of P/Q type calcium channels, which are abundant in nerve terminals. The protein content of vesicular glutamate and GABA transporters, and of the α1A subunit, was differently affected by diabetes in hippocampal and retinal...

  7. Towards a siRNA-containing nanoparticle targeted to breast cancer cells and the tumor microenvironment

    Gomes-da-Silva, Lígia C.; Santos, Adriana O.; Bimbo, Luís M.; Moura, Vera; Ramalho, José S.; Lima, Maria C. Pedroso de; Simões, Sérgio; Moreira, João N.
    The present work aimed at designing a lipid-based nanocarrier for siRNA delivery towards two cell sub-populations within breast tumors, the cancer and the endothelial cells from angiogenic tumor blood vessels. To achieve such goal, the F3 peptide, which is specifically internalized by nucleolin overexpressed on both those sub-populations, was used as a targeting moiety. The developed F3-targeted stable nucleic acid lipid particles presented adequate features for systemic administration. In addition, the attachment of the F3 peptide onto the liposomal surface enabled an internalization by both cancer and endothelial cells from angiogenic blood vessels that was significantly higher than the one...

  8. Glutathione redox cycle dysregulation in Huntington’s disease knock-in striatal cells

    Ribeiro, Márcio; Rosenstock, Tatiana; Cunha-Oliveira, Teresa; Ferreira, Ildete; Oliveira, Catarina R.; Rego, Ana Cristina
    Huntington’s disease (HD) is a CAG repeat disorder affecting the HD gene, which encodes for huntingtin (Htt) and is characterized by prominent cell death in the striatum. Oxidative stress was previously implicated in HD neurodegeneration, but the role of the major endogenous antioxidant system, the glutathione redox cycle, has been less studied following expression of full-length mutant Htt (FL-mHtt). Thus, in this work we analyzed the glutathione system in striatal cells derived from HD knock-in mice expressing mutant Htt versus wild-type cells. Mutant cells showed increased intracellular reactive oxygen species (ROS) and caspase-3 activity, which were significantly prevented following treatment...

  9. Revisiting oxidative stress and mitochondrial dysfunction in the pathogenesis of Parkinson disease-resemblance to the effect of amphetamine drugs of abuse

    Perfeito, Rita; Cunha-Oliveira, Teresa; Rego, Ana Cristina
    Parkinson disease (PD) is a chronic and progressive neurological disease associated with a loss of dopaminergic neurons. In most cases the disease is sporadic but genetically inherited cases also exist. One of the major pathological features of PD is the presence of aggregates that localize in neuronal cytoplasm as Lewy bodies, mainly composed of α-synuclein (α-syn) and ubiquitin. The selective degeneration of dopaminergic neurons suggests that dopamine itself may contribute to the neurodegenerative process in PD. Furthermore, mitochondrial dysfunction and oxidative stress constitute key pathogenic events of this disorder. Thus, in this review we give an actual perspective to classical...

  10. Disruption of striatal glutamatergic/GABAergic homeostasis following acute methamphetamine in mice

    Pereira, Frederico; Cunha-Oliveira, Teresa; Viana, Sofia; Travassos, Ana Sofia; Nunes, Sara; Silva, Carlos; Prediger, Rui; Rego, Ana Cristina; Ali, Syed; Fontes Ribeiro, Carlos Alberto
    Methamphetamine leads to functional changes in basal ganglia that are linked to impairment in motor activity. Previous studies from our group and others have shown that a single high-methamphetamine injection induces striatal dopaminergic changes in rodents. However, striatal glutamatergic, GABAergic and serotoninergic changes remain elusive under this methamphetamine regimen. Moreover, nothing is known about the participation of the receptor for advanced glycation end-products (RAGE), which is overexpressed upon synaptic dysfunction and glial response, on methamphetamine-induced striatal dysfunction. The aim of this work was to provide an integrative characterization of the striatal changes in amino acids, monoamines and astroglia, as well...

  11. Human periprostatic adipose tissue promotes prostate cancer aggressiveness in vitro

    Ribeiro, Ricardo; Monteiro, Cátia; Cunha, Virgínia; Oliveira, Maria José; Freitas, Mariana; Fraga, Avelino; Príncipe, Paulo; Lobato, Carlos; Lobo, Francisco; Morais, António; Silva, Vítor; Sanches-Magalhães, José; Oliveira, Jorge; Pina, Francisco; Mota-Pinto, Anabela; Lopes, Carlos; Medeiros, Rui
    Background - Obesity is associated with prostate cancer aggressiveness and mortality. The contribution of periprostatic adipose tissue, which is often infiltrated by malignant cells, to cancer progression is largely unknown. Thus, this study aimed to determine if periprostatic adipose tissue is linked with aggressive tumor biology in prostate cancer. Methods - Supernatants of whole adipose tissue (explants) or stromal vascular fraction (SVF) from paired fat samples of periprostatic (PP) and pre-peritoneal visceral (VIS) anatomic origin from different donors were prepared and analyzed for matrix metalloproteinases (MMPs) 2 and 9 activity. The effects of those conditioned media (CM) on growth and migration...

  12. Genetic screening of Alzheimer's disease genes in Iberian and African samples yields novel mutations in presenilins and APP

    Guerreiro, Rita João; Baquero, Miquel; Blesa, Rafael; Boada, Mercè; Brás, José Miguel; Bullido, Maria. J.; Calado, Ana; Crook, Richard; Ferreira, Carla; Frank, Ana; Gómez-Isla, Teresa; Hernández, Isabel; Lleó, Alberto; Machado, Álvaro; Martínez- Lage, Pablo; Masdeu, José; Molina-Porcel, Laura; Molinuevo, José L.; Pastor, Pau; Pérez-Tur, Jordi; Relvas, Rute; Oliveira, Catarina Resende; Ribeiro, Maria Helena; Rogaeva, Ekaterina; Sá, Alfredo; Samaranch, Lluís; Sánchez-Valle, Raquel; Santana, Isabel; Tàrraga, Lluís; Valdivieso, Fernando; Singleton, Andrew; Hardy, John; Clarimón, Jordi
    Mutations in three genes (PSEN1, PSEN2, and APP) have been identified in patients with early-onset (<65years) Alzheimer’s disease (AD). We performed a screening for mutations in the coding regions of presenilins, as well as exons 16 and 17 of the APP gene in a total of 231 patients from the Iberian peninsular with a clinical diagnosis of early onset AD (mean age at onset of 52.9 years; range 31– 64). We found three novel mutations in PSEN1, one novel mutation in PSEN2, and a novel mutation in the APP gene. Four previously described mutations in PSEN1 were also found. The same analysis was carried in 121...

  13. S4(13)-PV cell-penetrating peptide induces physical and morphological changes in membrane-mimetic lipid systems and cell membranes: Implications for cell internalization

    Cardoso, Ana M. S.; Trabulo, Sara; Cardoso, Ana L.; Lorents, Annely; Morais, Catarina M.; Gomes, Paula; Nunes, Cláudia; Lúcio, Marlene; Reis, Salette; Padari, Kärt; Pooga, Margus; Lima, Maria C. Pedroso de; Jurado, Amália S.
    The present work aims to gain insights into the role of peptide–lipid interactions in the mechanisms of cellular internalization and endosomal escape of the S4(13)-PV cell-penetrating peptide, which has been successfully used in our laboratory as a nucleic acid delivery system. A S4(13)-PV analogue, S4(13)-PVscr, displaying a scrambled amino acid sequence, deficient cell internalization and drug delivery inability, was used in this study for comparative purposes. Differential scanning calorimetry, fluorescence polarization and X-ray diffraction at small and wide angles techniques showed that both peptides interacted with anionic membranes composed of phosphatidylglycerol or a mixture of this lipid with phosphatidylethanolamine, increasing...

  14. BDNF regulates BIM expression levels in 3-nitropropionic acid-treated cortical neurons

    Almeida, S.; Laço, M.; Cunha-Oliveira, T.; Oliveira, C.R.; Rego, A.C.

  15. Mitochondrial dysfunction and caspase activation in rat cortical neurons treated with cocaine or amphetamine

    Cunha-Oliveira, T.; Rego, A.C.; Cardoso, S. M.; Borges, F.; Swerdlow, R.; Macedo, T.; Oliveira, C.R.

  16. Dysregulation of CREB Activation and Histone Acetylation in 3-Nitropropionic Acid-Treated Cortical Neurons: Prevention by BDNF and NGF

    Almeida, Sandra; Cunha-Oliveira, Teresa; Laço, Mário; Oliveira, Catarina R.; Rego, A. Cristina

  17. Expression of NR1/NR2B N-Methyl-d-Aspartate Receptors Enhances Heroin Toxicity in HEK293 Cells

    Domingues, António; Cunha-Oliveira, Teresa; Laço, Mário LN; Macedo, Tice; Oliveira, Catarina R; Rego, A Cristina
    Repeated use of drugs of abuse, namely opiates, has been shown to affect glutamate-releasing neurons. Moreover, blockade of N-methyl-D-aspartate (NMDA) receptors (NMDAR) prevents cell death by apoptosis induced by morphine, a heroin metabolite. Thus, in this article we investigated the involvement of different NMDAR subunits in heroin cytotoxicity. Human embryonic kidney (HEK293)cells, which do not express native NMDAR, were transfected with NR1/NR2A or NR1/NR2B subunits. As a control, cells were transfected with NR1 alone, which does not form functional channels. Incubation with heroin for 24 h induced a dose-dependent decrease in cell viability both in NR1-transfected and nontransfected cells. The...

  18. Toxic Effects of Opioid and Stimulant Drugs on Undifferentiated PC12 Cells

    Oliveira, M Teresa; Rego, A Cristina; Morgadinho, M Teresa; Macedo, Tice R; Oliveira, Catarina R
    Cell death and reactive oxygen species production have been suggested to be involved in neurodegeneration induced by the drugs of abuse. In this study we analyze the toxicity of the following drugs of abuse: heroin, morphine, d-amphetamine, and cocaine in undifferentiated PC12 cells, used as dopaminergic neuronal models. Our data show that opioid drugs (heroin and morphine) are more toxic than stimulant drugs (d-amphetamine and cocaine). Toxic effects induced by heroin are associated with a decrease in intracellular dopamine, an increase in DOPAC levels, and the formation of ROS, whereas toxic effects induced by amphetamine are associated with a decrease...

  19. Drugs of abuse induce apoptotic features in PC12 cells.

    Oliveira, M Teresa; Rego, A Cristina; Macedo, Tice R; Oliveira, Catarina R
    Drugs of abuse induce the release of dopamine in the central nervous system, particularly in the mesolimbic-mesocortical pathway. As dopamine may act as a neurotoxin, in this study, we analyzed the effects of the drugs of abuse, cocaine, heroin, and amphetamine, on the neurodegeneration of PC12 cells, a dopaminergic cell line, by evaluating the activity of caspase-3 and mitochondrial cytochrome c release. All the drugs were shown to induce caspase-3 activation, similarly to staurosporine, a classical inducer of apoptotic cell death. Furthermore, like staurosporine, the drugs of abuse induced a decrease in mitochondrial cytochrome c content, suggesting the involvement of...

  20. Consequences of mitochondrial dysfunction in Huntington's Disease and protection via phosphorylation pathways

    Cunha-Oliveira, Teresa; Ferreira, Ildete L; Rego, A Cristina
    Huntington’s Disease (HD) is an autosomal dominant neurodegenerative disorder clinically characterized by psychiatric disturbances, progressive cognitive impairment and choreiform movements. These symptoms are associated with the selective atrophy and neuronal loss in the striatum, cortex and hypothalamus. The disease is caused by a mutation at the 5’ terminal of the huntingtin (HTT) gene involving the expansion of CAG triplet, which encodes for glutamine. Mutant huntingtin (mHtt) may be cleaved by proteases originating neurotoxic fragments, and also undergoes conformational changes that lead to the formation of protein aggregates (Gil and Rego 2008, for review). Among several mechanisms of neurodegeneration, mHtt is related to mitochondrial dysfunction and relevant changes in energy...

Aviso de cookies: Usamos cookies propias y de terceros para mejorar nuestros servicios, para análisis estadístico y para mostrarle publicidad. Si continua navegando consideramos que acepta su uso en los términos establecidos en la Política de cookies.