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GB virus type C infection modulates T-cell activation independently of HIV-1 viral load

MAIDANA-GIRET, Maria Teresa; SILVA, Tania M.; SAUER, Mariana M.; TOMIYAMA, Helena; LEVI, Jose Eduardo; BASSICHETTO, Katia C.; NISHIYA, Anna; DIAZ, Ricardo S.; SABINO, Ester C.; PALACIOS, Ricardo; KALLAS, Esper Georges
Fonte: LIPPINCOTT WILLIAMS & WILKINS Publicador: LIPPINCOTT WILLIAMS & WILKINS
Tipo: Artigo de Revista Científica
ENG
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Background: Many clinical studies have suggested a beneficial effect of GB virus type C (GBV-C) on the course of HIV-1 infection, but the mechanisms involved in such amelioration are not clear. As recent evidence has implicated cellular activation in HIV-1 pathogenesis, we investigated the effect of GBV-C viremia on T-cell activation in early HIV-1 infection. Methods: Forty-eight recently infected HIV-1 patients (23 GBV-C viremic) were evaluated for T-cell counts, expanded immunophenotyping GBV-C RNA detection, and HIV-1 viral load. Nonparametric univariate and multivariate analyses were carried out to identify variables associated with cellular activation, including GBV-C status, HIV-1 viral load, T lymphocyte counts, and CD38 and chemokine (C-C motif) receptor 5 (CCR5) surface expression. Finding: We not only confirmed the positive correlation between HIV-1 viral load and the percentage of T cells positive for CD38(+)CD8(+) but also observed that GBV-C viremic patients had a lower percentage of T cells positive for CD38(+)CD4(+), CD38(+)CD8(+), CCR5(+)CD4(+), and CCR5(+)CD8(+) compared with HIV-1-infected patients who were not GBV-C viremic. In regression models, GBV-C RNA(+) status was associated with a reduction in the CD38 on CD4(+) or CD8(+) T cells and CCR5(+) on CD8(+) T cells...

Mecanismos de ativação mecânica de misturas de Níobio e Alumínio para a síntese por reação do NbAl3; Mechanical activation mechanisms of niobium and aluminium mixtures for the reaction synthesis of NbAl3

Rocha, Claudio Jose da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 28/03/2008 PT
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Neste trabalho, a moagem com alta energia foi utilizada para a ativação mecânica de misturas de pós de alumínio e nióbio, na proporção de 75% atômico de alumínio, para a síntese por reação de combustão do NbAl3. O objetivo foi investigar os mecanismos de ativação atuantes e a eventual preponderância de um deles. A moagem foi realizada tanto nos pós de alumínio e de nióbio separadamente (pré-ativação), como nas misturas. O processo de síntese por reação foi realizado no modo combustão simultânea, em pastilhas compactadas a partir de misturas com e sem ativação mecânica. O comportamento térmico das pastilhas foi registrado durante todo o ciclo térmico de aquecimento e, as principais características térmicas da reação de combustão, foram determinadas. O parâmetro de rede, o tamanho de cristalito e a microdeformação elástica do alumínio e do nióbio foram determinados por difratometria de raios X, mediante análise pelo método de Rietveld. A microscopia eletrônica de varredura foi utilizada para caracterização microestrutural dos pós moídos e da pastilha reagida. Constatou-se que o mecanismo preponderante de ativação mecânica é o aumento da área de interface, que ocorre durante a formação de agregados de partículas de alumínio e nióbio. A eficiência na formação de interfaces diminuiu com a utilização de nióbio pré-ativado (encruado) e com o aumento da quantidade de ácido esteárico (utilizado como agente controlador de processo durante a moagem). O efeito principal da ativação mecânica na síntese por reação de combustão foi a redução da temperatura de ignição com o aumento do tempo de moagem. A alta densidade de defeitos cristalinos...

Activation and early parthenogenesis of bovine oocytes treated with ethanol and strontium

Meo, S. C.; Leal, CLV; Garcia, J. M.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 35-46
ENG
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Efficient artificial activation is indispensable for the success of cloning programs. Strontium has been shown to effectively activate mouse oocytes for nuclear transfer procedures, however, there is limited information on its use for bovine oocytes. The present study had as objectives: (1) to assess the ability of strontium to induce activation and parthenogenetic development in bovine oocytes of different maturational ages in comparison with ethanol; and (2) to verify whether the combination of both treatments improves activation and parthenogenetic development rates. Bovine oocytes were in vitro matured for 24, 26, 28, and 30 h, and treated with ethanol (E, 7% for 5 min) or strontium chloride (S, 10 mM SrCl2 for 5 h) alone or in combination: ethanol + strontium (ES) and strontium + ethanol (SE). Activated oocytes were cultured in vitro in synthetic oviductal fluid (SOF) medium and assessed for pronuclear formation (15-16 h), cleavage (46-48 h) and development to the blastocyst stage (M). Treatment with ethanol and strontium promoted similar results regarding pronuclear formation (E, 20-66.7%; S, 26.7-53.3%; P > 0.05) and cleavage (E, 12.8-40.6%; S, 16.1-41.9%; P > 0.05), regardless of oocyte age. The actions of both strontium and ethanol were influenced by oocyte age: ethanol induced greater activation rates after 28 and 30 h of maturation (48.4 and 66.7% versus 20.0 and 23.3% for 24 and 26 It...

Oocyte activation and preimplantation development of bovine embryos obtained by specific inhibition of cyclin-dependent kinases

Perecin, F.; Méo, S.C.; Leal, C.L.V.; Garcia, J.M.
Fonte: Universidade Federal de Minas Gerais (UFMG), Escola de Veterinária Publicador: Universidade Federal de Minas Gerais (UFMG), Escola de Veterinária
Tipo: Artigo de Revista Científica Formato: 280-287
ENG
Relevância na Pesquisa
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Realizaram-se dois experimentos para avaliar a eficiência da bohemina e roscovitina associadas à ionomicina para ativação partenogenética e desenvolvimento embrionário inicial de bovinos. No primeiro, foram testadas diferentes concentrações (0, 50, 75 ou 100µM) e diferentes tempos de exposição (2, 4 ou 6 horas) à bohemina ou à roscovitina na ativação de oócitos bovinos maturados in vitro (MIV) pré-expostos à ionomicina. Os melhores tratamentos, bohemina 75µM e roscovitina 50µM, ambos por seis horas, foram utilizados no segundo experimento, no qual oócitos bovinos MIV foram expostos à ionomicina seguido ou não pelo tratamento com inibidores específicos das quinases dependentes de ciclina (CDKI), e avaliados quanto à configuração nuclear, taxa de ativação e desenvolvimento até blastocisto. Os tratamentos combinados (ionomicina+CDKI) apresentaram melhor taxa de ativação (77,3%) e desenvolvimento embrionário inicial (35,2%) do que a ionomicina sozinha (69,4% e 21,9%, respectivamente), e também promoveram ativação mais uniforme (aproximadamente 90% de formação de um pronúcleo). Estes resultados demonstram que os CDKIs potencializam o efeito da ionomicina na ativação e desenvolvimento embrionário inicial e podem auxiliar na obtenção de protocolos de ativação mais eficientes...

Artificial activation of bovine and equine oocytes with cycloheximide, roscovitine, strontium, or 6-dimethylaminopurine in low or high calcium concentrations

Fernandes, Claudia Barbosa; Devito, Liani Gasparini; Martins, Lilian Rigatto; Pria Blanco, Ieda Dala; Lima Neto, Joao Ferreria de; Tsuribe, Patricia Myakawa; Pereria Goncalves, Camila Gabriela; Landim-Alvarenga, Fernanda da Cruz
Fonte: Cambridge University Press Publicador: Cambridge University Press
Tipo: Artigo de Revista Científica Formato: 387-394
ENG
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Knowledge on parthenogenetic activation of oocytes is important to improve the efficiency of nuclear transfer (NT) and intracytoplasmic sperm injection (ICSI) because artificial activation of oocyte (AOA) is an essential step to achieve embryo production. Although different procedures for AOA have been established, the efficiency of in vitro production of embryos remains low, especially in equines and Bos taurus bovines. In an attempt to improve the techniques of NT and ICSI in bovine and equine species, we tested different combinations of drugs that had different mechanisms of action for the parthenogenetic activation of oocytes in these animals. The oocytes were collected, in vitro matured for 24 to 30 h and activated artificially, in the presence of low or high concentrations of calcium, with combinations of calcium ionophore (ionomycin) with cycloheximide, roscovitine, strontium, or 6-dimethylaminopurine (6-DMAP). For assessment of activation rates, oocytes were stained with Hoechst 33342 and observed under an inverted microscope. We showed that all combinations of drugs were equally efficient in activating bovine oocytes, with the best results obtained when high concentrations of calcium were adopted. For equine oocytes, high concentrations of calcium were not beneficial for the parthenogenetic activation and the combination of ionomycin with either 6-DMAP or roscovitine was effective in inducing artificial activation of oocytes. We believe that our preliminary findings provide some clues for the development of a better AOA protocol to be used with these species.

Overexpression of Fc receptor-like 1 associated with B-cell activation during hepatitis B virus infection

Wang,Ke; Pei,Hao; Huang,Biao; Yang,Run-Lin; Wu,Hang-Yuan; Zhu,Xue; Zhu,Lan
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2012 EN
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The role of B cells in the pathogenesis of hepatitis B virus (HBV) infection has not been explored in depth. In the present study, the activation status of B cells from peripheral blood of healthy controls (N = 20) and patients with acute hepatitis B (AHB, N = 15) or chronic hepatitis B (CHB, N = 30) was evaluated by measuring the expression levels of B-cell activation markers CD69 and CD86, using quantitative real-time PCR and flow cytometry. Moreover, the potential mechanism underlying B-cell activation during HBV infection was further investigated by analyzing the expression profile of FCRL1, an intrinsic activation molecule of B cells. An elevation in the levels of B-cell activation markers including CD69 and CD86 was observed in the AHB patients (44.31 ± 9.27, 27.64 ± 9.26%) compared to CHB patients (30.35 ± 11.27, 18.41 ± 6.56%, P < 0.05), which was still higher than healthy controls (12.23 ± 7.84, 8.22 ± 3.43%, P < 0.05). Furthermore, the expression of FCRL1 was found to be similar to B-cell activation markers, which was highest in AHB patients (70.15 ± 17.11%), lowest in healthy donors (36.32 ± 9.98%, P < 0.05) and half-way between these levels in patients with CHB (55.17 ± 12.03%, P < 0.05). The results were positively associated with aberrant B-cell activation. These data suggest that B cells can play a role in HBV infection...

Oocyte activation and preimplantation development of bovine embryos obtained by specific inhibition of cyclin-dependent kinases

Perecin,F.; Méo,S.C.; Leal,C.L.V.; Garcia,J.M.
Fonte: Universidade Federal de Minas Gerais, Escola de Veterinária Publicador: Universidade Federal de Minas Gerais, Escola de Veterinária
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2007 EN
Relevância na Pesquisa
333.9293%
The efficiency of bohemine and roscovitine in combination with ionomycin on parthenogenetic activation and initial embryonic development of bovine oocytes was studied. Two experiments were performed: in the first, different concentrations (0, 50, 75 or 100µM) and different exposure periods (2, 4 or 6 hours) to bohemine or roscovitine were tested for activation rates of in vitro matured (IVM) bovine oocytes, which were pre-exposed to ionomycin. The best treatments, 75µM bohemine and 50µM roscovitine, both for 6h, were used in the second experiment, in which IVM bovine oocytes were exposed to ionomycin, followed or not by bohemine or roscovitine treatment, and evaluated for nuclear status, activation rate and blastocyst development were assessed. The combined treatments (ionomycin + cyclin-dependent kinases inhibitors - CDKIs) showed better results for activation rates (77.3%) and initial embryonic development (35.2%) than the single ionomycin treatment (69.4% for activation and 21.9% for development); and also lead to a more uniform activation (nearly 90% single pronucleus development). The results showed that CDKIs improve the effects of ionomycin on parthenogenetic activation and blastocyst development in bovine oocytes and could help to achieve more efficient activation protocols...

Improved relationship between left and right ventricular electrical activation after cardiac resynchronization therapy in heart failure patients can be quantified by body surface potential mapping

Samesima,Nelson; Pastore,Carlos Alberto; Douglas,Roberto Andres; Martinelli Filho,Martino; Pedrosa,Anisio A.
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2013 EN
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OBJECTIVES: Few studies have evaluated cardiac electrical activation dynamics after cardiac resynchronization therapy. Although this procedure reduces morbidity and mortality in heart failure patients, many approaches attempting to identify the responders have shown that 30% of patients do not attain clinical or functional improvement. This study sought to quantify and characterize the effect of resynchronization therapy on the ventricular electrical activation of patients using body surface potential mapping, a noninvasive tool. METHODS: This retrospective study included 91 resynchronization patients with a mean age of 61 years, left ventricle ejection fraction of 28%, mean QRS duration of 182 ms, and functional class III/IV (78%/22%); the patients underwent 87-lead body surface mapping with the resynchronization device on and off. Thirty-six patients were excluded. Body surface isochronal maps produced 87 maximal/mean global ventricular activation times with three regions identified. The regional activation times for right and left ventricles and their inter-regional right-to-left ventricle gradients were calculated from these results and analyzed. The Mann-Whitney U-test and Kruskall-Wallis test were used for comparisons...

Carbon-carbon bond activation of acetylene derivatives via photolysis of platinum complexes

Gunay, Ahmet (1978 - ); Jones, William D.
Fonte: University of Rochester. Publicador: University of Rochester.
Tipo: Tese de Doutorado Formato: Number of Pages:xix, 261 leaves
ENG
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Thesis (Ph. D.)--University of Rochester. Dept. of Chemistry, 2008.; Activation of C-C bonds with the help of transition metal complexes remains one of the most challenging fields in organometallic chemistry because of their inertness which arises from poor kinetic accessibility and thermodynamic stability. Efficient activation of C-C bonds will have potential applications in organic synthesis, petroleum processing, and pharmaceutical research, as it will help convert naturally abundant traditionally unreactive molecules to useful raw materials. In order to provide a driving force for C-C bond activation, relief of ring strain and attainment of aromaticity have been employed, as has forcing the target C-C bond into close proximity to the transition metal center. A new method which does not utilize the above strategies to activate the C-C bonds has been discovered by our group. Development and further examination of this new method are described in this thesis. Carbon-carbon bond activation of diphenylacetylene and several substituted derivatives has been studied via photolysis of platinum compounds. Pt0-acetylene complexes with η2-coordination of the alkyne, along with the corresponding PtII C-C activated photolysis products...

I. Energetics of C–H bond activation of functionalized hydrocarbons. II. C–H and C–CN bond activation of acetonitrile and benzonitrile; Energetics of C–H bond activation of functionalized hydrocarbons. II. C–H and C–CN bond activation of acetonitrile and benzonitrile; C–H and C–CN bond activation of acetonitrile and benzonitrile; II. C–H and C–CN bond activation of acetonitrile and benzonitrile

Evans, Meagan Elizabeth (1981 - ); Jones, William D.
Fonte: University of Rochester Publicador: University of Rochester
Tipo: Tese de Doutorado Formato: Illustrations:ill.; Number of Pages:xvii, 226 leaves
ENG
Relevância na Pesquisa
336.03527%
Thesis (Ph. D.)--University of Rochester. Dept. of Chemistry, 2011.; Several transition-metal systems have been used to establish correlations between metal-carbon and carbon-hydrogen bonds. In the following studies, the [Tp’RhL] fragment where Tp’ = tris(3,5-dimethylpyrazolyl)borate and L = neopentyl isocyanide, is used to investigate C–H bond activation of molecules with strong C–H bonds. The first study (Chapter 2) examines C–H bond activation of fluorinated aromatic hydrocarbons. Photolysis of the precursor, Tp’RhL(carbodiimide) in neat fluoroarene resulted in C–H activation products of the type, Tp’RhL(arylF)H. Both the kinetic and thermodynamic selectivities of rhodium for different C–H bonds on the fluorinated aromatic were examined. A strong thermodynamic preference was observed for C–H activation ortho to two fluorine atoms as opposed to one. Competition experiments along with ΔGre≠ values allow for the determination of relative Rh–Caryl bond strengths and illustrate the large ortho fluorine effect on the strength of the Rh–Caryl bond. This study was the first to quantize experimentally the effect of an ortho fluorine on the strength of the metal–carbon bond. In a similar study...

A biochemical analysis of the activation of the Drosophila caspase DRONC

Dorstyn, L.; Kumar, S.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
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333.9293%
The activation of caspases is the principal event in the execution of apoptosis. Initiator caspases are activated through an autocatalytic mechanism often involving dimerisation or oligomerisation. In Drosophila, the only initiator caspase DRONC, is tightly inhibited by DIAP1 and removal of DIAP1 permits activation of DRONC by the Drosophila Apaf-1-related killer, ARK. ARK is proposed to facilitate DRONC oligomerisation and autoprocessing at residue E352. This study examines whether autoprocessing of DRONC is required for its activation and for DRONC-mediated cell death. Using purified recombinant proteins, we show here that while DRONC autocleaves at residue E352, mutation of this site did not abolish enzyme activation, DRICE-induced cleavage of DRONC or DRONC-mediated activation of DRICE. We performed a detailed mutational analysis of DRONC cleavage sites and show that overexpression of DRONC cleavage mutants in Drosophila cells retain pro-apoptotic activity. Using an in vitro cell-free assay, we found ARK alone did not activate DRONC and demonstrate a requirement for an additional cytosolic factor in ARK-mediated DRONC activation. These results suggest that, similar to mammalian caspase-2 and caspase-9, the initial cleavage of DRONC is not essential for its activation and suggest a mechanism of ARK-mediated DRONC activation different from that proposed previously.; L Dorstyn and S Kumar

An in-vitro evaluation of the effectiveness of endodontic irrigants, with and without sonic and laser activation, in the eradication of Enterococcus faecalis biofilm.

Seet, Aaron Nicholas
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2011
Relevância na Pesquisa
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Introduction: It is well established that the causative agent of endodontic disease is the presence and growth of bacteria (Kakehashi et al., 1965; Möller et al., 1981). Therefore, eradication of bacteria is essential to prevent or eliminate apical periodontitis. Studies have shown that elimination of bacteria prior to obturation has resulted in a more favourable outcome for endodontic therapy (Sjögren et al., 1997). When endodontic treatment fails, bacteria is often isolated from the root canals of these teeth. One of the most commonly isolated bacteria is Enterococcus faecalis (Molander et al., 1998; Sundqvist et al, 1998). As such, endodontic therapy is founded upon three principles: mechanical instrumentation; irrigation with antimicrobial agents and placement of an intracanal medicament (Haapasalo et al., 2005). However, the complex anatomy of the root canal system often prevents the penetration of irrigants and medicaments into recesses that cannot be accessed by mechanical instrumentation. The advent of sonic, ultrasonic and laser instruments has led to many investigations looking at their potential for the activation of irrigants (Lee et al., 2004; de Gregorio et al., 2009; De Moor et al., 2009). However, most of these studies have concentrated on the removal of dentinal debris and smear layer (Lee et al....

New Players in Platelet Activation and Apoptosis; Neue FaKtoren in Thrombozytenaktivierung und Apoptose

Towhid, Syeda Tasneem
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
EN
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333.9293%
The non-nucleated platelets are the key players in thrombosis and haemostasis and versatile mediators of inflammation and immunity. Their life, death and actions define illness and health of men. This dissertation attempted to find what events lead to the apoptotic death in platelets by nutraceutical thymoquinone, pathogen-associated peptidoglycan, the antibiotic vancomycin and finally how platelet activation and death by a recently reported chemokine CXCL16 influence platelet function. Thymoquinone triggers suicidal death of blood platelets in a Phosphoinositide 3Kinase-dependent manner, possibly through a G-protein Coupled Receptor family opioid receptor; an effect paralleled by increase of cytosolic Ca(2+) activity, ceramide formation, mitochondrial depolarization, and caspase-3 activation. HPLC-purified fractions of peptidoglycan from Staphylococcus aureus 113 triggers apoptosis of platelets, characterized by annexin-V binding, increase of [Ca2+]i, mitochondrial depolarization, caspase-3 activation and integrin alphaIIbbeta3 upregulation. The annexin-V binding was significantly blunted by anti-TLR-2 antibodies, in the absence of extracellular Ca2+ and by pancaspase inhibitor zVAD-FMK (1 µM). Vancomycin decreased cell volume, triggered annexin V-binding...

Discrete Emotion and Motivation: Relative activation in Appetitive and Aversive Motivational System as a Function of Anger, Sadness, Fear, and Joy embedded in the Content of Televised Information Campaigns.

Lee, Seungjo
Fonte: [Bloomington, Ind.] : Indiana University Publicador: [Bloomington, Ind.] : Indiana University
Tipo: Doctoral Dissertation
EN
Relevância na Pesquisa
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Thesis (PhD) - Indiana University, Mass Communications/Telecommunications, 2007; The goal of this study was to examine whether predictable motivational activation in the appetitive and aversive systems underlies the production and experience of discrete emotions (anger, sadness, joy, and fear) experienced while viewing televised PSAs. The current study was conducted from the perspective of LC4MP which theorizes that conscious emotional experience is evoked by the activated motivational systems. This study used self-reports and physiological measures in order to index motivational activation and emotional experience. In joy condition, physiological data provide moderate support for strong appetitive activation and no support for aversive inhibition while self-reported data provided good evidence for both. In fear condition, the self-reported data supported the predictions of strong aversive and inhibited appetitive activation during fear. The physiological data provide strong support for a highly activated aversive system but no support for an inhibited appetitive system. In sadness condition, the self-reported and physiological data support the prediction that sadness is a moderately activated aversive condition and that it may involve some low level appetitive activation. In anger condition...

Activation tagging in Solanum tuberosum: Innate immune activation affects potato tuber periderm development

Frank, Daniel
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
333.53016%
Activation-tagging is a functional genomics technique where strong enhancers are inserted randomly into target genomes to over-activate endogenous genes. Phenotypes of interest can be selected for investigation of genetic factors contributing to the mutant phenotype. From initial screens of a population of activation-tagged potato, a mutant with chocolate-coloured tuber skin has been identified. In this thesis, a novel sequence capture method for identifying T-DNA loci in activation tagged potato was used to characterize chocolate’s single T-DNA insertion locus. Transcriptome analysis of tuber periderm tissue was used to identify major processes occurring in the chocolate mutant. Our data suggest activation of a chitin-binding receptor-like kinase located 65 kb from T-DNA insert may cause activation of immune signaling pathways in chocolate. The present work explores a putative model of transcriptional and cellular responses involved in gain-of-function immune receptor activation. Selectively, these findings illustrate the periderm tissue as an important area of defense charged against biotic and abiotic stresses. Periderm development and anatomy are highly important for tuber storage. Further characterization of potato tuber periderm may contribute knowledge to model periderm systems and have implications for molecular breeding strategies to improve tuber storage quality.; Thesis (Master...

THE ROLE OF NEU1 SIALIDASE IN Trk TYROSINE KINASE RECEPTOR ACTIVATION

Jayanth, Preethi
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
334.26305%
The signaling pathways of tyrosine kinase Trk receptors and their downstream biological effects are well known, but the parameters controlling the interactions between the receptors and their natural ligands still remain to be defined. Recent published reports from our laboratory indicate that nerve growth factor (NGF)-induced TrkA receptor activation is dependent on a membrane cellular sialidase. This sialidase activity specifically targets and hydrolyzes sialyl α-2, 3-linked β-galactosyl residues resulting in the desialylation and activation of the receptor. These findings support a novel hypothesis that places mammalian sialidase(s) in a cycle of activation of these receptors by their natural ligand. Taken together, they also predict a prerequisite desialylation of Trk receptors caused by a sialidase on the cell surface enabling the removal of a steric hindrance to receptor dimerization. Until now, the sialidase associated with neurotrophin-treated live Trk-expressing cells has not been identified. The molecular mechanism(s) of sialidase activation by neurotrophin factors binding to their receptors also remains unknown. In this thesis, the novel role of Neu1 sialidase in the activation of ligand-induced TrkA and TrkB receptors has been identified. It has been reported for the first time that Neu1 is already in complex with naïve and ligand-induced Trk receptors. In addition...

Temperature variation in pulp chamber during dental bleaching in presence or absence of light activation

Mollica,Fernanda Brandão; Rocha,Daniel Maranha da; Travassos,Alessandro Caldas; Valera,Marcia Carneiro; Araujo,Maria Amélia Maximo de
Fonte: Pontifícia Universidade Católica do Rio Grande do Sul Publicador: Pontifícia Universidade Católica do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 EN
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PURPOSE: In addition to the chemical damage due to bleaching gels penetration into the pulp during pulp vitality dental bleaching, another possible aggressive factor could be the heat generated by the exothermal oxidation reaction of the bleaching gel, which may also be aggravated by the use of light activation. This study assessed the temperature variation in the pulp chamber in human teeth, using three different bleaching gels with or without LED light activation. METHODS: Thirty human pre-molars were cut longitudinally to obtain buccal and lingual halves. The 60 specimens were divided into 3 groups, and the bleaching gel used varied as follows: 35% hydrogen peroxide (WHP); 37% carbamide peroxide (W) and 38% hydrogen peroxide (OX). Half of the specimens were submitted to bleaching with light activation and, the other half, without light activation. The light source used was the light emitting diode appliance (LED, 3-Light, Clean Line), and the intrapulpal temperatures were measured by using a digital thermometer. Data were analyzed by ANOVA and Tukey's tests (alpha=5%). RESULTS: The intrapulpal temperatures (inºC) were as follows: without light activation (WHP= 0.68b; W= 0.40b; OX= 0.48b); with light activation (WHP= 2.35a; W= 1.60a; OX= 1.80a ). CONCLUSION: LED light activation of bleaching gels increased the temperature in the pulp chamber...

Latent and Active Tuberculosis Infection Increase Immune Activation in Individuals Co-Infected with HIV☆☆☆★

Sullivan, Zuri A.; Wong, Emily B.; Ndung'u, Thumbi; Kasprowicz, Victoria O.; Bishai, William R.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
EN_US
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In recent years, chronic immune activation and systemic inflammation have emerged as hallmarks of HIV disease progression and mortality. Several studies indicate that soluble inflammatory biomarkers (sCD14, IL-6, IL-8, CRP and hyaluronic acid), as well as surface markers of T-cell activation (CD38, HLA-DR) independently predict progression to AIDS and mortality in HIV-infected individuals. While co-infections have been shown to contribute to immune activation, the impact of latent tuberculosis infection (LTBI), which is widely endemic in the areas most affected by the global AIDS epidemic, has not been evaluated. We hypothesized that both active and latent states of Mycobacterium tuberculosis co-infection contribute to elevated immune activation as measured by these markers. In HIV-infected individuals with active, but not latent TB, we found elevated levels of soluble markers associated with monocyte activation. Interestingly, T-cell activation was elevated individuals with both latent and active TB. These results suggest that in the highly TB- and HIV-endemic settings of southern Africa, latent TB-associated T-cell activation may contribute to HIV disease progression and exacerbate the HIV epidemic. In addition, our findings indicate that aggressive campaigns to treat LTBI in HIV-infected individuals in high-burden countries will not only impact TB rates...

Selective activation of the developmentally regulated Ha hsp17.6 G1 promoter by heat stress transcription factors

Rojas, Anabel; Almoguera, Concepción; Carranco, Raúl; Klaus-Dieter, Scharf; Jordano, Juan
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artículo Formato: 276752 bytes; application/pdf
ENG
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333.9293%
Using two well-characterized heat stress transcription factors (Hsfs) from tomato (Lycopersicon peruvianum; LpHsfA1 and LpHsfA2), we analyzed the transcriptional activation of the Ha hsp17.6 G1 promoter in sunflower (Helianthus annuus) embryos. In this system, we observed transient promoter activation only with LpHsfA2. In contrast, both factors were able to activate mutant versions of the promoter with improved consensus Hsf-binding sites. Exclusive activation by LpHsfA2 was also observed in yeast (Saccharomyces cerevisiae) without other Hsfs and with a minimal Cyc1 promoter fused to the Ha hsp17.6 G1 heat stress cis-element. Furthermore, the same promoter mutations reproduced the loss of activation selectivity, as observed in sunflower embryos. The results of in vitro binding experiments rule out differential DNA binding of the two factors as the explanation for the observed differential activation capacity. We conclude that the specific sequence of this heat stress cis-element is crucial for Hsf promoter selectivity, and that this selectivity could involve preferential transcriptional activation following DNA binding. In sunflower embryos, we also observed synergistic transcriptional activation by co-expression of LpHsfA1 and LpHsfA2. Mutational analyses of the Ha hsp17.6 G1 promoter...

Continual low-level activation of the classical complement pathway

Manderson, A; Pickering, Mark; Botto, Marina; Walport, Mark J; Parish, Christopher
Fonte: Rockefeller University Press Publicador: Rockefeller University Press
Tipo: Artigo de Revista Científica
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There is evidence that the classical complement pathway may be activated via a "C1-tickover" mechanism, analogous to the C3-tickover of the alternative pathway. We have quantitated and characterized this pathway of complement activation. Analysis of freshly collected mouse and human plasma revealed that spontaneous C3 activation rapidly occurred with the generation of C3 fragments in the plasma. By the use of complement- and Ig-deficient mice it was found that C1q, C4, C2, and plasma Ig were all required for this spontaneous C3 activation, with the alternative complement pathway further amplifying C3 fragment generation. Study of plasma from a human with C1q deficiency before and after therapeutic C1q infusion confirmed the existence of a similar pathway for complement activation in humans. Elevated levels of plasma C3 were detected in mice deficient in complement components required for activation of either the classical or alternative complement pathways, supporting the hypothesis that there is continuous complement activation and C3 consumption through both these pathways in vivo. Blood stasis was found to stimulate C3 activation by classical pathway tick-over. This antigen-independent mechanism for classical pathway activation may augment activation of the complement system at sites of inflammation and infarction.