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.

FFUC- Artigos em Revistas Internacionais

Mostrando recursos 1 - 20 de 263

  1. 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...

  2. 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...

  3. Naproxen co-crystals with pyridinecarboxamide isomers

    Castro, Ricardo; Ribeiro, João; Maria, Teresa; Ramos Silva, Manuela; Yuste-Vivas, Consuelo; Canotilho, João; Eusébio, Ermelinda
    A screening of naproxen cocrystals with coformers picolinamide, nicotinamide, isonicotinamide, and pyrazinamide is performed by the Kofler contact method and mechanochemistry. The solids obtained by mechanochemistry are characterized by differential scanning calorimetry, DSC, polarized light thermomicroscopy, PLTM, infrared spectroscopy, FTIR, and X-ray powder diffraction, XRPD. No cocrystal could be prepared under the experimental conditions investigated between naproxen and pyrazinamide, which bears two aromatic nitrogen atoms, ortho and meta to the amide group. For the o-, m-, and p-pyridinecarboxamide isomers, regardless of the aromatic nitrogen position, the coformer interacts with naproxen to give rise to new cocrystals: naproxen:picolinamide, naproxen2:nicotinamide, and naproxen:isonicotinamide....

  4. Bismuth(III) Reagents in Steroid and Terpene Chemistry

    Salvador, Jorge A. R.; Silvestre, Samuel M.; Pinto, Rui M. A.
    Steroid and terpene chemistry still have a great impact on medicinal chemistry. Therefore, the development of new reactions or “greener” processes in this field is a contemporaneous issue. In this review, the use of bismuth(III) salts, as “ecofriendly” reagents/catalysts, on new chemical processes involving steroids and terpenes as substrates will be focused. Special attention will be given to some mechanistic considerations concerning selected reactions.

  5. Complexos de inclusão de indometacina com hidroxipropil-β- ciclodextrina. Estudos de dissolução e coeficiente de partição

    Rama, Ana Cristina Ribeiro; Veiga, Francisco; Figueiredo, Isabel Vitória; Sousa, Adriano; Caramona, Margarida
    A indometacina, antiinflamatório não-esteróide, é praticamente insolúvel em água. A hidroxipropil-β-ciclodextrina confere aos fármacos nela incluídos melhores características de solubilidade. A formação de complexos com indometacina protege da hidrólise, aumentando a solubilidade. O objetivo desse trabalho foi estudar a influência da complexação por liofilização e por spray-dried, na dissolução e coeficiente de partição. Os resultados dos estudos de dissolução dos complexos de inclusão obtidos por liofilização quando comparados com os obtidos por spray-dryer, apresentam quer maior velocidade de dissolução quer melhor eficiência de dissolução. Os resultados da análise do coeficiente de partição, com ambos os métodos de complexação, confirmam a teoria de que são várias as forças intervenientes neste processo e não...

  6. Effect of Food on the Pharmacokinetic Profile of Etamicastat (BIA 5-453)

    Vaz-da-Silva, Manuel; Nunes, Teresa; Rocha, José F.; Falcão, Amílcar; Almeida, Luis; Soares-da-Silva, Patricio
    Background Etamicastat is a novel, potent, and reversible peripheral dopamine-β-hydroxylase inhibitor that has been administered orally at doses up to 600 mg once daily for 10 days to male healthy volunteers and appears to be well tolerated. Objective The aim of this study was to investigate the effect of food on the pharmacokinetics of etamicastat. Material and Methods A single-center, open-label, randomized, two-way crossover study in 12 healthy male subjects was performed. Subjects were administered a single dose of etamicastat 200 mg following either a standard high-fat and high-calorie content meal (test) or 10 hours of fasting (reference). The statistical method for testing the...

  7. Recent Developments in Molecular Dynamics Simulations of Fluorescent Membrane Probes

    Loura, Luís M. S.; Ramalho, J. P. Prates
    Due to their sensitivity and versatility, the use of fluorescence techniques in membrane biophysics is widespread. Because membrane lipids are non-fluorescent, extrinsic membrane probes are widely used. However, the behaviour of these probes when inserted in the bilayer is often poorly understood, and it can be hard to distinguish between legitimate membrane properties and perturbation resulting from probe incorporation. Atomistic molecular dynamics simulations present a convenient way to address these issues and have been increasingly used in recent years in this context. This article reviews the application of molecular dynamics to the study of fluorescent membrane probes, focusing on recent work with complex design fluorophores and ordered bilayer...

  8. Protecção Ambiental e Práticas Quotidianas Individuais e Colectivas

    Moreno, Mª José S. M.; Pedrosa, Mª Arminda
    Nesta comunicação, referindo os programas 3E ́s (resíduos sólidos urbanos), apresentam-se as características gerais dos programas SAFra (saúde/ambiente/fitofarmacêuticos – resíduos agrícolas) e ERA (energias renováveis e ambiente), que visam estimular práticas quotidianas, individuais e colectivas, de protecção ambiental. Estes programas de intervenção social diversificada consubstanciam-se em acções protagonizadas por um grupo de estudantes, designado EQOFAR (Estudantes de Química Orgânica de Farmácia: Acção/Reacção), interrelacionam-se com a disciplina de Química Orgânica da licenciatura em Ciências Farmacêuticas, da Universidade de Coimbra. As metodologias adoptadas para fomentar o desenvolvimento de competências científicas dos estudantes EQOFAR, as intervenções comunitárias dos programas desenvolvidos pelo grupo e a introdução deste tipo de práticas de ensino e de...

  9. Bioactivity of Isoflavones: Assessment through a Theoretical Model as a Way to Obtain a “Theoretical Efficacy Related to Estradiol (TERE)”

    Campos, Maria da Graça R.; Matos, Miguel Pires
    The increase of human life span will have profound implications in Public Health in decades to come. By 2030, there will be an estimated 1.2 billion women in post-menopause. Hormone Replacement Therapy with synthetic hormones is still full of risks and according to the latest developments, should be used for the shortest time possible. Searching for alternative drugs is inevitable in this scenario and science must provide physicians with other substances that can be used to treat the same symptoms with less side effects. Systematic research carried out on this field of study is focusing now on isoflavones but the...

  10. 3-Oxoandrosta-4,6-dien-17[beta]-yl 2-methyl-1H-imidazole-1-carboxylate and 3-oxo-5[alpha]-androst-17[beta]-yl 2-methyl-1H-imidazole-1-carboxylate: C-H...[pi] and [pi]-[pi] intermolecular interactions

    Silva, Manuela Ramos; Moreira, Vânia M.; Cardoso, Cláudia; Beja, Ana Matos; Salvador, Jorge A. R.
    The title compounds, C24H30N2O3, (I), and C24H34N2O3, (II), both contain an androstane backbone and a 2-methylimidazole-1-carboxylate moiety at the 17-position. Compound (I) contains two symmetry-independent molecules (denoted 1 and 2), while compound (II) contains just one molecule in the asymmetric unit. The C-C-O-C torsion angle that reflects the twisting of the 2-methylimidazole-1-carboxylate moiety from the mean steroid plane is 143.1 (2)° for molecule 1 of (I), 73.1 (3)° for molecule 2 of (I) and 86.63 (17)° for (II). The significance of this study lies in its observation of significant differences in both molecular conformation and supramolecular aggregation between the molecules...

  11. Conformation of 17-chloro-16-formylandrosta-5,16-dien-3[beta]-yl acetate and 17-chloroandrosta-5,16-dien-3[beta]-yl acetate

    Silva, Manuela Ramos; Moreira, Vânia M.; Cardoso, Cláudia; Beja, Ana Matos; Salvador, Jorge A. R.
    In the title compounds, C22H29ClO3, (I), and C21H29ClO2, (II), respectively, the B rings adopt a half-chair conformation and the D rings adopt an envelope conformation. A twist of the steroid skeleton of both compounds is observed. There is a positional disorder of the acetoxy group of (II), with the terminal atoms disordered over two positions with near equal occupancy. Quantum-mechanical ab initio calculations using a molecular orbital Hartree–Fock method were performed for the isolated molecules, thus allowing the distinction within the structural features of these two androstane derivatives of which characteristics are intrinsic to the molecules and which are due to packing effects. The skeletal twisting was found to be innate to...

  12. 5β,6β-Epoxy-17-oxoandrostan-3β-yl acetate and 5β,6β-epoxy-20-oxopregnan-3β-yl acetate

    Pinto, Rui M. A.; Salvador, Jorge A. R.; Paixão, José A.
    In the title compounds, C21H30O4, (I), and C23H34O4, (II), respectively, which are valuable intermediates in the synthesis of important steroid derivatives, rings A and B are cis-(5β,10β)-fused. The two molecules have similar conformations of rings A, B and C. The presence of the 5β,6β-epoxide group induces a significant twist of the steroid nucleus and a strong flattening of the B ring. The different C17 substituents result in different conformations for ring D. Cohesion of the molecular packing is achieved in both compounds only by weak intermolecular interactions. The geometries of the molecules in the crystalline environment are compared with those...

  13. Intranasal drug delivery: how, why and what for?

    Pires, Anaísa; Fortuna, Ana; Alves, Gilberto; Falcão, Amílcar
    Over the recent decades the interest in intranasal delivery as a non-invasive route for drugs is increased. Since the nasal mucosa offers numerous benefits as a target tissue for drug delivery, a wide variety of therapeutic compounds may be administered intranasally for topic, systemic and central nervous system action. We have, herein, outlined the relevant aspects of nasal anatomy, physiology and histology, and the biological, physicochemical and pharmaceutical factors that must be considered during the process of discovery and development of nasal drugs as well as in their incorporation into appropriate nasal pharmaceutical formulations.

  14. The Sensitizer 2,4-Dinitrofluorobenzene Activates Caspase-3 and Induces Cell Death in a Skin Dendritic Cell Line

    Cruz, Maria Teresa; Duarte, Carlos B.; Gonçalo, Margarida; Figueiredo, Américo; Carvalho, Arsélio P.; Lopes, Maria Celeste
    In this work, a dendritic cell line derived from mouse skin (FSDC) was used, as an in vitro experimental model, to evaluate the cytotoxic effect of two chemical sensitizers, a strong sensitizer (2,4-dinitrofluorobenzene, DNFB) and a weak sensitizer (2,4- dichloronitrobenzene, DCNB). The results indicated that DNFB reduces the cellular metabolism of FSDC, as evaluated by the reduction of the tetrazolium salt, 3-(4,5-Dimethylthiazol-2-yl)-2,5- diphenyl tetrazolium bromide (MTT). All the DNFB concentrations tested, ranging from 5.2 ¹M to 26¹M, significantly inhibited the MTT reduction after 1 hour of cell exposure to the sensitizer. In contrast, incubation of FSDC with the weak sensitizer DCNB had no significant effect on the MTT reduction assay. When...

  15. Pharmacokinetic-pharmacodynamic interaction between Nebicapone and controlled-release levodopa/benserazide:a single-center, fase I, double-blind, randomized, placebo-controlled, four-way crossover study in healthy subjects

    Nunes, Teresa; Rocha, José F.; Fernendes-Lopes, Carlos; Costa, Raquel; Torrão, Leonel; Loureiro, Ana I.; Falcão, Amílcar; Vaz-da-Silva, Manuel; Wright, Lyndon; Almeida, Luís; Soares-da-Silva, Patrício
    Background: Nebicapone is a reversible catechol-O-methyltransferase (COMT) inhibitor. Coadministration of a COMT inhibitor with levodopa and a dopa-decarboxylase inhibitor (carbidopa or benserazide) increases levodopa exposure and its therapeutic effect. Objectives: The primary objective of this study was to investigate the effect of nebicapone (50, 100, and 200 mg), compared with placebo, on levodopa pharmacokinetics when coadministered with a single dose of controlled-release levodopa 100 mg/benserazide 25 mg. The secondary objectives were to investigate the effect of nebicapone on the erythrocyte-soluble COMT (S-COMT) activity and on the plasma levels of the levodopa 3-O-methylated metabolite (3-O-methyldopa [3-OMD]). Nebicapone’s tolerability was also assessed. Methods: This was a single-center, Phase...

  16. The maximal electroshock seizure (MES) model in the preclinical assessment of potential new antiepileptic drugs

    Castel-Branco, M. M.; Alves, G. L.; Figueiredo, I. V.; Falcão, Amílcar; Caramona, M. M.
    The choice of appropriate animal models for the initial in vivo testing of potential anticonvulsant compounds is one of the most important steps in the successful search for new antiepileptic drugs. The purpose of this paper is to describe the most important aspects to take into account when performing the maximal electroshock seizure (MES) test in the routine laboratory screening of new antiepileptics: the conventional and threshold MES test experimental procedures, the factors affecting experimental data (laboratory conditions, administration vehicles and drug formulations, time after drug administration, and stimulus duration and site of stimulation) and the assessment of anticonvulsant activity are discussed.

  17. Dexamethasone prevents granulocyte-macrophage colonystimulating factor-induced nuclear factor-kB activation, inducible nitric oxide synthase expression and nitric oxide production in a skin dendritic cell line

    Vital, Ana Luísa; Gonçalo, Margarida; Cruz, M. Teresa; Figueiredo, Américo; Duarte, Carlos B.; Lopes, M. Celeste
    AIMS: Nitric oxide (NO) has been increasingly implicated in inflammatory skin diseases, namely in allergic contact dermatitis. In this work, we investigated the effect of dexamethasone on NO production induced by the epidermal cytokine granulocyte / macrophage colony-stimulating factor (GM-CSF) in a mouse fetal skin dendritic cell line.Methods: NO production was assessed by the method of Griess. Expression of the inducible isoform of nitric oxide synthase (iNOS) protein was evaluated by western blot analysis and immunofluorescence microscopy. Western blot analysis was also performed to evaluate cytosolic IkappaB-alpha (IkB-a) protein levels. The electrophoretic mobility shift assay was used to evaluate the activation or inhibition of nuclear factor kappa B (NF-kB).Results: GM-CSF induced iNOS expression and NO production,...

  18. Assessment of strategies to increase chondrocyte viability in cryopreserved human osteochondral allografts: evaluation of the glycosylated hydroquinone, arbutin

    Rosa, Susana Carvalho; Gonçalves, Juliana; Judas, Fernando; Lopes, Celeste; Mendes, Alexandrina Ferreira
    Objective: Allogeneic cartilage is used to repair damaged areas of articular cartilage, requiring the presence of living chondrocytes. So far, no preservation method can effectively meet that purpose. Identification of more effective cryoprotective agents (CPAs) can contribute to this goal. The aim of this study was to determine whether the glycosylated hydroquinone, arbutin, alone or in combination with low concentrations of other CPAs, has cryoprotective properties towards human articular cartilage. Material and methods: Human tibial plateaus were procured from multi-organ donors, with the approval of the Ethics Committee of the University Hospital of Coimbra. The tibial plateaus were treated with or without arbutin (50 or...

  19. Contact sensitizer nickel sulfate activates the transcription factors NF-kB and AP-1 and increases the expression of nitric oxide synthase in a skin dendritic cell line

    Cruz, M. Teresa; Gonçalo, Margarida; Figueiredo, Américo; Carvalho, Arsélio P.; Duarte, Carlos B.; Lopes, M. Celeste
    Nuclear factor kappa B (NF-kB) and activating protein-1 (AP-1) transcription factors are ubiquitously expressed signaling molecules known to regulate the transcription of a large number of genes involved in immune responses, namely the inducible isoform of nitric oxide synthase (iNOS). In this study, we demonstrate that a fetal skin-derived dendritic cell line (FSDC) produces nitric oxide (NO) in response to the contact sensitizer nickel sulfate (NiSO4) and increases the expression of the iNOS protein, as determined by immunofluorescence and Western blot analysis. The sensitizer NiSO4 increased cytoplasmic iNOS expression by 31.9+10.3% and nitrite production, as assayed by the Griess reaction, by 27.6+9.5%. Electrophoretic mobility shift assay (EMSA), showed that 30min of...

  20. Screening of Five Essential Oils for Identification of Potential Inhibitors of IL-1-induced Nf-κB Activation and NO Production in Human Chondrocytes: Characterization of the Inhibitory Activity of α-Pinene

    Neves, Ângela; Rosa, Susana; Gonçalves, Juliana; Rufino, Ana; Judas, Fernando; Salgueiro, Lígia; Lopes, Celeste; Cavaleiro, Carlos; Mendes, Alexandrina Ferreira
    Nuclear factor-κB is a key transcription factor activated by pro-inflammatory signals, like interleukin-1β (IL-1), being required for the expression of many inflammatory and catabolic mediators, such as nitric oxide (NO), that play an important role in arthritic diseases. This work aimed at screening and identifying natural inhibitors of IL-induced NF-κB activation and NO production in human articular chondrocytes. Five essential oils obtained from four plants of the Iberian flora, Mentha x piperita L. (Lamiaceae), Origanum virens L. (Lamiaceae), Lavandula luiseri L. (Lamiaceae), and Juniperus oxycedrus L. subsp. oxycedrus (Cupressaceae), were screened for their ability to prevent IL-1-induced NO production. The oil...

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