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‣ Role of acetylcholine receptors in proliferation and differentiation of P19 embryonal carcinoma cells

RESENDE, R. R.; ALVES, A. S.; BRITTO, L. R. G.; ULRICH, H.
Fonte: ELSEVIER INC Publicador: ELSEVIER INC
Tipo: Artigo de Revista Científica
Português
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Coordinated proliferation and differentiation of progenitor cells is the base for production of appropriate numbers of neurons and glia during neuronal development in order to establish normal brain functions. We have used murine embryonal carcinoma P19 cells as an in vitro model for early differentiation to study participation of nicotinic (nAChR) and muscarinic acetylcholine (mAChR) receptors in the proliferation of neural progenitor cells and their differentiation to neurons. We have previously shown that functional nicotinic acetylcholine receptors (nAChRs) already expressed in embryonic cells mediate elevations in cytosolic free calcium concentration ([Ca2+](i)) via calcium influx through nAChR channels whereas intracellular stores contribute to nAChR- and mAChR-mediated calcium fluxes in differentiated cells [Resende et al., Cell Calcium 43 (2008) 107-121]. In the present study, we have demonstrated that nicotine provoked inhibition of proliferation in embryonic cells as determined by BrdU labeling. However, in neural progenitor cells nicotine stimulated proliferation which was reversed in the presence of inhibitors of calcium mobilization from intracellular stores, indicating that liberation of intracellular calcium contributed to this proliferation induction. Muscarine induced proliferation stimulation in progenitor cells by activation of G alpha(q/11)-coupled M-1...

‣ Caracterização do papel das proteínas quinases C (PKCs) na proliferação e auto-renovação das células tronco embrionárias murinas; Characterization of the role of protein kinases C (PKC) in proliferation and self-renewal of murine embryonic stem cells

Garavello, Nicole Milaré
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/08/2011 Português
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Células tronco embrionárias (CTE) são capazes de proliferar indefinidamente mantendo a sua pluripotência, isto é, a capacidade de se diferenciar em diversos tipos celulares perante estímulos adequados. Esse potencial tem sido intensamente estudado, de modo a permitir a utilização dessas células em terapias de reposição celular. Trabalhos anteriores demonstraram que as proteínas kinases C (PKC) são importantes moduladores moleculares de cascatas de sinalização que levam ao processo de proliferação e auto-renovação das CTE. Porém o papel exato das diferentes isoenzimas das PKCs ainda não foi elucidado. Isso ocorre porque a família das PKCs é composta por pelo menos dez isoenzimas e apenas, recentemente, desenvolveram-se moduladores específicos para as diferentes isoenzimas, o que permitirá estudar o papel específico dessas quinases. No presente trabalho verificamos que a ativação da PKCδ induziu a proliferação de CTE indiferenciadas sem induzir a diferenciação das mesmas. Para tentar elucidar as vias de sinalização mediadas pela PKCδ que levam à proliferação das CTE indiferenciadas realizamos estudos de fosfoproteômica o que possibilitou a identificação de potenciais alvos diretos e indiretos da PKCδ. Dentre os alvos identificados foram encontradas diversas proteínas relacionadas com proliferação...

‣ Sinergia entre os receptores purinérgicos e o fator de crescimento de nervos (NGF) na diferenciação e proliferação de células tronco neurais; Synergy between purinergic receptors and nerve growth factor (NGF) in the differentiation and proliferation of neural stem cells

Oliveira, Rodrigo La Banca de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/07/2013 Português
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Os receptores purinérgicos são divididos em receptores P1 e P2 de acordo com o seu agonista endógeno, os receptores metabotrópicos P1 são ativados por adenosina, enquanto os metabotrópicos P2Y e ionotrópicos P2X são estimulados através do ATP e outros nucleotídeos. Além de sua função bem estabelecida na neurotransmissão, a sinalização purinérgica tem despertado crescente interesse científico devido à sua importância nas funções no metabolismo celular, incluindo os processos de desenvolvimento embrionário e reparação de tecidos. Isso ocorre especialmente no sistema nervoso central, onde eles controlam a proliferação, diferenciação, apoptose e a liberação de fatores neurotróficos. Nesse trabalho nós focamos nas ações sinérgicas entre a sinalização purinérgica e o fator de crescimento de nervos (NGF), tendo em vista três formas conhecidas de interação entre o NGF e os receptores purinérgicos, a potencialização dos efeitos do NGF através de uma ligação cruzada entre as vias, a regulação da expressão dos receptores purinérgicos pelo NGF e regulação da liberação de NGF pela adenosina. Com o objetivo de investigar estes processos sinérgicos na regulação da proliferação, migração e determinação fenotípica...

‣ DETECTION OF CELL-PROLIFERATION IN TISSUE-SECTIONS

Bacchi, C. E.; Gown, A. M.
Fonte: Associação Brasileira de Divulgação Científica (ABRADIC) Publicador: Associação Brasileira de Divulgação Científica (ABRADIC)
Tipo: Artigo de Revista Científica Formato: 677-687
Português
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1. Cell proliferation is of interest since abnormal cell proliferation appears to be a precursor of tumorigenesis and also because the quantitative description of cell proliferation in tumors can be used to predict the biological behavior of a particular neoplasia.2. Them am several reliable methods of studying cell proliferation in tissues. One of the most important is the detection of the Ki67 defined antigen in frozen sections. The number of cells expressing Ki67 correlates with histological grades of tumors and can also be predictive of clinical outcome. The Ki67 can be localized in tissue sections using monoclonal antibodies in association with the immunoperoxidase technique.3. Proliferating cell nuclear antigen (PCNA) is a component of DNA polymerase-delta and is another important cell proliferation marker manifesting a striking increase in concentration during the S phase of the cell cycle. 19A2 and PC10 are two different monoclonal antibodies which can be employed to detect PCNA in paraffin-embedded tissues.4. Molecular biology has also been making a great contribution to the study of cell proliferation. The most recent innovation in tissue identification of proliferating cells is the use of in situ hybridization for the localization of histone H3 and/or H4 mRNA. H3 mRNA-positive cells appear to be present in basal cells of the skin and in crypt cells of the intestine which are sites with high proliferation rate.

‣ O complexo de rutênio doador de óxido nítrico trans-[ru(NO)Cl(cyclam)](PF6)2 inibe a proliferação e migração de células musculares lisas vasculares induzida pelo fator de crescimento derivado de plaquetas; The ruthenium complex nitric oxide donor trans -[ru(NO)Cl(cyclam)](PF6)2 inhibits vascular smooth muscle cell proliferation and migration induced by platelet derived growth factor

Mariana Gonçalves de Oliveira
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 05/08/2013 Português
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O óxido nítrico (NO) é um multifuncional agente biológico que nas últimas décadas tem sido alvo de uma infinidade de estudos e constitui hoje um dos mais importantes mediadores de processos intra e extracelulares. Diversos estudos demonstram sua capacidade de prevenção da ativação e adesão plaquetária ou leucocitária e inibição da proliferação e migração de células musculares lisas vasculares (VSMCs), entretanto, em condições de baixa disponibilidade do NO esses processos são prejudicados. Atualmente há o grande interesse no desenvolvimento de compostos capazes de liberar NO de forma modulada e estável, e, nesse sentido, os complexos nitrosilos de rutênio têm se destacado por suas características excepcionais. É amplamente reconhecido que a modulação fenotípica de VSMCs tem papel crítico na progressão de diversas doenças vasculares proeminentes. Sabe-se que o fator de crescimento derivado de plaquetas (PDGF-BB) é um dos principais estimulantes desse processo. Este estudo se propôs a caracterizar os efeitos inibitórios do complexo de rutênio trans-[Ru(NO)Cl(cyclam)](PF6)2, nomeado Ru(cyclam)NO, na modulação fenotípica, resposta proliferativa e migratória de VSMCs induzidas por PDGF-BB. VSMCs foram obtidas por técnica de cultura primária. A citotoxicidade do complexo...

‣ Estudo imunoistoquímico da angiogênese, proliferação celular e da enzima ácido graxo sintase (FASN) em tumores malignos primários de glândulas salivares maiores e menores = : Immunohistochemical study of angiogenesis, cellular proliferation and fatty acid synthase (FASN) in minor and major primary malignant salivary gland tumors; Immunohistochemical study of angiogenesis, cellular proliferation and fatty acid synthase (FASN) in minor and major primary malignant salivary gland tumors

Katya Pulido Diaz
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/02/2014 Português
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Introdução: Os tumores das glândulas salivares (TGS) são lesões incomuns e correspondem a aproximadamente 3 a 10% das neoplasias que acometem a região de cabeça e pescoço. A angiogênese, proliferação celular e a expressão da enzima ácido graxo sintase (FASN) podem interferir nos mecanismos de progressão tumoral e comportamento clínico dos tumores malignos de glândulas salivares. Objetivos: Avaliar imunoistoquímicamente a angiogênese, índice de proliferação celular e expressão de FASN em tumores malignos de glândulas salivares maiores e menores e correlacionar a expressão destes biomarcadores com os dados clínicos e agressividade histopatológica além de comparar a expressão de FASN e Ki67 entre 12 casos de adenoma pleomorfo e 6 de carcinoma ex-adenoma pleomorfos. Pacientes e Métodos: Foram utilizadas 52 peças cirúrgicas de pacientes portadores de tumores malignos de glândulas salivares maiores e menores e 12 de adenomas pleomorfos como controle do marcador FASN e Ki67. As amostras de tecidos dos TGS malignos foram submetidas a reações imunoistoquímicas para os anticorpos CD31, CD34, CD105, e para ambos tipos de tumores Ki-67 e FASN. Para a quantificação microvascular e determinação da proliferação celular utilizamos os métodos quantitativos Microvessel Analysis Algorithm e Nuclear Image Analysis Algorithm com o software ImageScope (Aperio Scanscope® CS System). Foi utilizado o método semi-quantitativo convencional para a análise do marcador FASN. Resultados: O local anatômico mais acometido foi a parótida (67...

‣ Retinol binding protein 4 promotes hyperinsulinism-induced proliferation of rat aortic smooth muscle cells

LI, FEI; XIA, KE; SHEIKH, MD SAYED ALI; CHENG, JINFANG; LI, CHUANCHANG; YANG, TIANLUN
Fonte: D.A. Spandidos Publicador: D.A. Spandidos
Tipo: Artigo de Revista Científica
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Recent studies have suggested that retinol binding protein 4 (RBP4), an adipocytokine related to insulin resistance (IR), may play an important role in the development of atherosclerosis and cardiovascular diseases (CVD). Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) is one of the most common causes of atherosclerosis. Hyperinsulinism promotes proliferation of VSMCs through the MAPK pathway. However, whether RBP4 is involved in insulin-induced proliferation of VSMCs leading to atherosclerosis remains unclear. In the present study, we evaluated the role of RBP4 and the potential relevance of signaling pathways in this process. Different concentrations of RBP4 (1 and 4 μg/ml) were added to rat aortic smooth muscle cells (RASMCs) during insulin-induced proliferation. The levels of cell growth signaling pathway proteins ERK1/2, p-ERK1/2, JAK2, p-JAK2, STAT3 and p-STAT3 were assessed by western blotting in order to identify the pathway(s) that are activated during insulin-induced proliferation. The specific inhibitors of ERK1/2 (PD98059) and JAK2 (AG490) were used to confirm our findings. Insulin induced proliferation of RASMCs in a concentration- and time-dependent manner, and increased the expression of ERK1/2...

‣ Rôle de GPR40 dans la survie et la prolifération cellulaires induites par l’oléate dans les cellules de cancer du sein MDA-MB-231 et de cancer de la prostate DU145

St-Onge, Geneviève
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
Português
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La relation entre l’obésité et le cancer, bien qu’établie par des études épidémiologiques, est peu connue. Pourtant, environ 25 % des cancers pourraient y être attribuables. Parmi les cancers reliés à l’obésité, les cancers du côlon, du sein chez les femmes ménopausées et de la prostate sont les plus fréquents. Des études sur modèles animaux ont suggéré une association positive entre une diète riche en gras et le développement du cancer mammaire et de la prostate. Nous avons étudié les mécanismes moléculaires par lesquels les acides gras influencent le devenir de lignées de cellules cancéreuses du sein et de la prostate. Ces travaux ont montré que les acides gras insaturés, dont l’oléate, induisent la prolifération cellulaire tandis que les acides gras saturés, dont le palmitate, diminuent la prolifération. Un traitement à l’oléate stimule la formation de gouttelettes lipidiques dans le cytoplasme des cellules de cancer du sein MDA-MB-231 et de la prostate DU145 alors qu’un traitement au palmitate entraîne l’apoptose. Le mécanisme d’action de l’oléate sur la prolifération a été étudié de façon plus approfondie. L’utilisation d’inhibiteurs pharmacologiques nous a permis de déterminer que l’effet prolifératif de l’oléate implique la voie PI3K/Akt...

‣ L’étude du rôle d’ARF1 dans la migration et la prolifération des cellules du cancer du sein

Boulay, Pierre-Luc
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
Português
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Les facteurs d’ADP-ribosylation (ARFs) sont des petites GTPases impliquées dans le transport vésiculaire, la synthèse des lipides membranaires et la réorganisation du cytosquelette d’actine. Les isoformes 1 (ARF1) et 6 (ARF6) sont les plus étudiées. ARF1 est connue pour être distribuée à l’appareil de Golgi, alors qu’ARF6 est confinée principalement à la membrane plasmique. Récemment, il a été démontré qu’ARF6 est hautement exprimée et activée dans plusieurs cellules de cancer du sein invasif et que celle-ci contrôle les processus de migration et d’invasion. Cependant, le rôle d’ARF1 dans ces processus biologiques impliqués dans la formation de métastases du cancer du sein demeure méconnu. Dans la présente étude, nous avons utilisé comme modèle d’étude pour ARF1 les MDA-MB-231, une lignée de cellules invasives du cancer du sein exprimant de haut niveau de récepteurs au facteur de croissance épidermique (EGFR). Afin d’évaluer le rôle d’ARF1 dans la migration, dans la transition épithéliale mésenchymateuse (EMT) et dans la prolifération cellulaire, nous avons procédé à deux types d’approches expérimentales, soit l’inhibition de l’expression endogène d’ARF1 par l’interférence à l’ARN de même que la surexpression de formes mutantes dominante négative (ARF1T31N) et constitutivement active d’ARF1 (ARF1Q71L)...

‣ Clonal proliferation of hepatocytes during chronic hepatitis B virus infection.

Tu, Thomas
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2012 Português
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Chronic hepatitis B virus (HBV) infection causes liver disease that can progress to cirrhosis and hepatocellular carcinoma (HCC). Changes in the hepatocyte population that occur from the early immune-tolerant stage of infection to late-stage disease outcomes remain unclear. We hypothesised that some hepatocytes lose HBV antigen expression and escape the HBVspecific immune response, allowing them to undergo clonal proliferation. Clonal proliferation of altered hepatocytes may be a marker of disease progression and may have a direct role in the development of HCC. Liver tissues from 30 patients were analysed, including patients with early-stage HBV infection, late-stage infection with cirrhosis, or with HCC. Unique virus-cell DNA junctions formed by the integration of HBV DNA into the host cell genome were detected using inverse nested PCR (invPCR). The copy number of unique virus-cell DNA junctions was used as a measure of clonal proliferation of hepatocytes. A computer simulation of a liver undergoing stochastic liver turnover was used to determine if the hepatocyte clones observed by invPCR could have been formed by random chance. Immunohistochemistry for HBV surface antigen (HBsAg) expression and Imaging Mass Spectrometry (IMS) for cellular protein expression were carried out to detect cellular changes that may be associated with clonal proliferation. Significantly (p<0.01) larger clones were observed by invPCR in liver DNA extracts of patients with late-stage HBV-associated disease (≤280000 hepatocytes) compared to patients in early-stage HBV infection (8-1124 hepatocytes). Computer simulations indicated that stochastic turnover could not produce clones of >10000 hepatocytes...

‣ The proliferation of rodent astrocytes – implications for a modulatory role of dopamine and aquaporin 4; Astrozytenproliferation in Ratten und Mäusen – Hinweise für eine regulierende Rolle von Dopamine und Aquaporin 4

Wachter, Britta
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
Português
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Astrocytes of the striatum express both dopamine receptors and transporters, which indicates that dopamine plays a functional role in striatal astrocytes. Dopamine is known to modulate proliferation of precursor cells during development and also in the adult brain. However, it is unknown whether dopamine affects proliferation of astrocytes. In this study we investigated a putative role of dopamine on the proliferation of striatal astrocytes in vitro and in vivo. Using striatal mouse astrocyte cultures we found that dopamine decreased proliferation of astrocytes and the expression of the water channel AQP4, more precisely the isoform M23, both on the mRNA and protein levels. We hypothesized that the decreased expression of the water channel is linked to the observed decrease in proliferation. Under physiological conditions, the striatum represents a target area of dopaminergic projections arising in the midbrain. We hypothesized that dopamine might keep AQP4 expression at a low level and hence prevent proliferation of astrocytes in the striatum in vivo. Consequentially, in vivo depletion of dopamine should result in an increased expression of AQP4 and an increase of proliferation of astrocytes. To investigate this hypothesis we intraventricularily injected 6-hydroxydopamine...

‣ In-vitro-Untersuchungen zur Zellstimulation durch Thrombozytenkonzentrate (PRP); Stimulation of cell proliferation by Platelet Rich Plasma (PRP): In-vitro-experiments

Seher, Gabriela Aida
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
Português
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Die Wirkung von Platelet Rich Plasma (PRP) bezüglich einer Stimulation der Zellproliferation wurde in vitro untersucht. Die Versuche wurden mit Präosteoblasten und Osteoblasten durchgeführt. In verschiedenen Versuchssystemen wurden sowohl komplette PRP-Präparationen als auch einzelne Komponenten von PRP untersucht. Die Wirkung der aus PRP freigesetzten angereicherten Wachstumsfaktor-fraktion (PRP-Überstand) wurde mit der Wirkung der reinen Plasma-Komponenten (Platelet Poor Plasma) und den durch die Gerinnungsaktivatoren Calcium und Thrombin hervorgerufenen Effekten verglichen. Die wichtigsten Erkenntnisse lassen sich wie folgt zusammenfassen: · Höhere Ca-Konzentrationen, wie sie bei der Aktivierung von PRP vorkommen, haben einen eher hemmenden Effekt auf die Zellproliferation, Thrombin kann dagegen, zumindest in geringen Konzentrationen, eine Erhöhung der Zellproliferation bewirken. · PRP erhöht zwar, unter allen hier eingesetzten Versuchsbedingungen, die Zellproliferation, ein gleicher oder vergleichbarer Effekt wurde jedoch auch in der Kontrollgruppe (PPP) und teilweise mit Thrombin erzielt. · Die Förderung der Zellproliferation durch PRP, PPP oder Thrombin überschritt nie die unter optimalen Zellkulturbedingungen (Zellen in voll supplementiertem Medium) erzielten Wachstumsraten. · Insgesamt wurden keine Belege für die von Marx und anderen [Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;85(6):638-646.] für PRP postulierten Wirkungsmechanismen (Stimulation von Zellen durch Freisetzung von Wachstumsfaktoren aus a-Granula der Thrombozyten) gefunden. · Da in PPP keine spezifische Anreicherung von Wachstumsfaktoren stattfindet...

‣ Einfluss des Anthranilsäurederivats Glafeninhydrochlorid auf die Proliferation, klonogene Aktivität, den Zellzyklus und das Migrationsvermögen von humanen aortalen glatten Muskelzellen und Endothelzellen in vitro; Impact of glafenine hydrochloride on human endothelial cells and human vascular smooth muscle cells: a substance reducing proliferation, migration and extracellular matrix synthesis

Tran, Quoc Bao
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
Português
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Das Ziel dieser Studie war es, den Einfluss von Glafeninhydrochlorid (einer nicht-steroidalen, antiinflammatorischen Substanz) auf die Proliferation, die klonogene Aktivität, den Zellzyklus, die Migration, den Zellaufbau und die extrazelluläre Synthese des Matrixproteins Tenascin bei humanen aortalen glatten Muskelzellen (haSMC) und humanen endothelialen Zellen (EC) in vitro zu untersuchen. HaSMC und EC wurden in Zellkulturflaschen ausgesät. Die Zellen wurden 4 Tage lang mit Glafeninhydrochlorid (10mM, 50 mM und 100 mM) behandelt. Die Hälfte der behandelten Gruppen wurde erneut mit Glafeninhydrochlorid inkubiert, die andere Hälfte erhielt Glafeninhydrochlorid-freies Kulturmedium; Wiederholung alle 4 Tage bis Tag 20. Wachstumskinetiken und klonogene Aktivitäten wurden erhoben. Die Zellzyklusverteilung wurde mittels FACS untersucht, das Migrationsvermögen ausgewertet und die Effekte auf die extrazelluläre Matrixsynthese mittels Immunfluoreszenz ausgewertet. Glafeninhydrochlorid inhibierte die Proliferation und klonogene Aktivität von haSMC und EC in einer konzentrationsabhängigen Weise. Ein G2-Phasenblock und eine Verminderung der G1-Phase wurden festgestellt. Das Migrationsvermögen der haSMC wurde dosisabhängig beeinflusst und die extrazelluläre Synthese des Matrixproteins Tenascin vermindert. Da Glafeninhydrochlorid das Potential besitzt...

‣ Kultivierung von Zellen aus Atheromen des Menschen und die Beeinflussung ihres Wachstums; Cultivation of cells from human atherosclerotic lesions : inhibitory and stimulatory effects on cell proliferation

Voisard, Rainer
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Buch (Monographie)
Português
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1. Kultivierung von Plaquezellen des Menschen Die Migration und Proliferation von glatten Muskelzellen aus der Media in den subendothelialen Raum wird als Schlüsselereignis bei der Entstehung der Atherogenese angesehen. Um weitere Informationen über das Wachstumsverhalten dieser Zellen zu erhalten, wurden aus atherosklerotischem Plaquematerial Zellen isoliert und ihre Wachstumscharakteristika in Zellkulturen untersucht. Die Entnahme des Plaquematerials erfolgte perkutan durch einen Atherektomie-Katheter aus der A. femoralis superficialis, der A. poplitea und der A. renalis und im Rahmen von operativen Eingriffen aus der A. coronaria, der A. carotis und der Aorta abdominalis. Die Mehrzahl dieser Zellen konne durch positive Reaktion mit Antikörpern gegen glattmuskuläres alpha-Aktin als glatte Muskelzellen identifiziert werden. Hierbei zeigten Zellen aus re-stenosierendem Plaquematerial ein extrem gesteigertes Wachstum im Vergleich zu Zellen aus primär-stenosierendem Plaquematreial. Diese unterschiedlichen Wachstumsraten wurden unabhängig von der Entnahme-Technik und -Lokalisation registriert. Das gesteigerte Wachstum der glatten Muskelzellen aus restenosierendem Plaquematerial könnte das in vitro-Äquivalent zu dem oftmals rapide verlaufendem Re-stenosierungsprozeß nach Angioplastie in vivo sein. 2. Einflüsse auf das Wachstumsverhalten In unseren Versuchen zeigte sich eine zunehmende proliferative Aktivität der Zellen durch steigende Serumkonzentrationen. Plaquezellen aus Restenosen proliferierten bei geringeren Konzentrationen und in stärkerem Ausmaß als Plaquezellen aus primär-stenosierenden Läsionen. Durch das Kulturmedium von re-stenosierenden glatten Muskelzellen konnte das Wachstum von primär-stenosierenden glatten Muskelzellen um 60% gesteigert werden. Der Wachstumsfaktor PDGF steigert die Proliferation von glatten Muskelzellen um das 2.7-fache...

‣ Cell proliferation and cancer

Lopez-Saez, J.F.; De la Torre, C.; Pincheira, J.; Gimenez-Martin, G.
Fonte: Murcia : F. Hernández Publicador: Murcia : F. Hernández
Tipo: Artigo de Revista Científica Formato: application/pdf
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The discovery that phosphorylation of selected proteins by cyclin-dependent kinases is the engine which makes the cycle run provides a new image of the control of proliferation and of its deregulation. The high conservation of this machinery in the different eukaryotic organisms emphasizes its early origin and its importance for life. It also makes the extrapolation of findings between different species feasible. The control of proliferation relies basically on accelerating and braking mechanisms which act on the engine driving the cycle. This review particularly stresses the importance of checkpoint or tumor suppressor pathways as transduction systems of negative signals which may induce a cycle braking operation. They prevent any important cycle transition, as the initiation of proliferation, that of replication, mitosis, etc., until the DNA and other cellular conditions make such a progression safe. These checkpoint pathways are able to recognize and transduce signals about the adequacy of initiating or continuing proliferation for a cell at a particular time, under a particular set of external and internal conditions. Crucial components of these pathways are proteins encoded by some of the checkpoint genes that evaluate the final balance of mitogenic and antimitogenic pathways reaching them and...

‣ Australia, the 'Saudi Arabia' of uranium? Proliferation and security concerns

Yaxley, Kerrie
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Relatório
Português
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Recently the world has seen a renewed interest in nuclear energy. Australia has large uranium reserves and, according to some commentators, could benefit from this renewed interest. Australia could become the' Saudi Arabia' of uranium exporters. This could include enriching uranium in Australia for export overseas. Nuclear weapons and nuclear energy are inextricably linked. The technology to create reactor grade material can also create weapons grade material. Thus the global security situation and the effectiveness of the international safeguards regime need to be examined before exports are increased and enrichment is considered. During the Cold War, the nuclear threat was a bilateral arms race between the United States (US) and the Soviet Union (USSR). In the post Cold War context the nuclear threat has not dissipated. The new threat is multi-faceted and widespread. It comes in the form of nuclear terrorism, clandestine nuclear weapons programs, illicit trafficking of nuclear materials and regional arms races. These factors all show weaknesses in the Nuclear Non- Proliferation Regime (NPR). The NPR protects Australian Obligated Nuclear Materials (AONM). Australia is a signatory to the Nuclear Non-Proliferation Treaty (NPT). The International Atomic Energy Agency (IAEA)...

‣ The Proliferation Security Initiative: Origins, Operations and the Potential for Future Formalisation

Minns, Angus
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Relatório
Português
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The Proliferation Security Initiative (PSI) marked a distinct change in the manner in which the United States and the rest of the world sought to address the threat posed by the proliferation of nuclear weapons as well as other types of WMD. It was the first of a swathe of counterproliferation initiatives that were to be instigated in the wake of the US's post September 11 preemptive security doctrine. The US and its principal allies asserted that a non-traditional and more proactive approach to combat proliferation was required in such a context. Primarily as a result of non-traditional security threats posed by possibility of a rogue state, or non-state actor obtaining WMDs. The PSI was heralded as a flexible counterproliferation initiative, which would be considerably more effective at addressing these non-traditional threats as opposed to the existing network of formalised non-proliferation treaties. Initially the PSI brought together the US and ten other nations (who came to be known as the Core Group) in a political agreement. The focus of the agreement was on creating a network of nations who would work cooperatively to interdict air and sea shipments of WMD components to and between undesirable states. However, the international legitimacy of the initiative has proved a challenge for the parties. This is due to the PSI's nature as a political agreement...

‣ Le niveau réduit d’AMPc dans la surexpression des protéines G(alpha)i et la prolifération accrue des cellules du muscle lisse vasculaire des rats spontanément hypertendus

Gusan, Svetlana
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
Português
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Nous avons précédemment montré que les cellules musculaires lisses vasculaires(CMLV) des rats spontanément hypertendus (SHR) présentent une expression augmentée des protéines G inhibitrices (Gi) et une prolifération cellulaire accrue par rapport aux CMLV des rats Wystar-Kyoto (WKY). Le niveau d'AMPc s’est également avéré plus faible dans les CMLV de SHR. La présente étude a donc été entreprise afin d'examiner la contribution de la diminution du niveau intracellulaire d'AMPc à l’augmentation de l'expression des protéines Gi et à la prolifération accrue des CMLV de SHR et de continuer à explorer les mécanismes moléculaires sous-jacents responsables de cette réponse. Les CMLV de SHR ont montré par rapport aux CMLV des WKY une expression accrue de Giα-2 et Giα-3 qui a été diminué d'une manière dépendante de concentration par le dbcAMP, un analogue d'AMPc perméable à la membrane cellulaire. En outre, les fonctions augmentées des protéines Gi comme démontrées par l'amplification de l’inhibition de l'adénylate cyclase par les hormones inhibitrices et l'activité forskoline (FSK)-stimulée de l’adénylate cyclase par une faible concentration de GTPγS dans les CMLV de SHR ont également été restaurées aux niveaux de WKY par le dbcAMP. La prolifération accrue des CMLV de SHR a également été atténuée par le dbcAMP et la forskoline...

‣ Proliferation of differentiated glial cells in the brain stem

Barradas,P.C.; Cavalcante,L.A.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/1998 Português
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Classical studies of macroglial proliferation in muride rodents have provided conflicting evidence concerning the proliferating capabilities of oligodendrocytes and microglia. Furthermore, little information has been obtained in other mammalian orders and very little is known about glial cell proliferation and differentiation in the subclass Metatheria although valuable knowledge may be obtained from the protracted period of central nervous system maturation in these forms. Thus, we have studied the proliferative capacity of phenotypically identified brain stem oligodendrocytes by tritiated thymidine radioautography and have compared it with known features of oligodendroglial differentiation as well as with proliferation of microglia in the opossum Didelphis marsupialis. We have detected a previously undescribed ephemeral, regionally heterogeneous proliferation of oligodendrocytes expressing the actin-binding, ensheathment-related protein 2'3'-cyclic nucleotide 3'-phosphodiesterase (CNPase), that is not necessarily related to the known regional and temporal heterogeneity of expression of CNPase in cell bodies. On the other hand, proliferation of microglia tagged by the binding of Griffonia simplicifolia B4 isolectin, which recognizes an alpha-D-galactosyl-bearing glycoprotein of the plasma membrane of macrophages/microglia...

‣ Las señales purinérgicas como reguladores de la proliferación y muerte celular durante la regeneración de la retina de pez cebra; Purinergic signals as regulators of proliferation and cell death during regeneration of the zebrafish retina

Battista, Ariadna Gabriela
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2011 Português
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La retina de los peces óseos, a diferencia de la retina de los mamíferos, posee células progenitoras multipotentes que proliferan a lo largo de toda la vida del animal, originando todos los tipos celulares retinianos, que se agregan al tejido diferenciado a medida que éste crece. Este crecimiento ocurre en una región histológicamente distinguible, ubicada entre la retina neural y el epitelio ciliar, denominada zona ciliar marginal (CMZ), cuyas células poseen capacidad proliferativa. Esta zona representa un anillo de tejido, alrededor de la retina madura, donde existe un gradiente de diferenciación celular, que comprende tanto stem cells (más periféricas) como células progenitoras ya comprometidas con determinados fenotipos retinianos (más centrales). Una característica sorprendente de la retina adulta de pez es que posee la capacidad de regenerarse completamente en respuesta al daño. Por consiguiente, la retina de este vertebrado ofrece características únicas para el estudio de los factores extracelulares e intracelulares que dirigen la proliferación celular y que llevan a la regeneración del tejido adulto. Tanto algunas neuronas como células gliales de la retina, así como también las células del epitelio pigmentario...