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Compartmentalized phosphodiesterase 4D isoforms expression, targeting and localization in vascular myocytesTruong, Tammy 14 March 2014 (has links)
During the development of atherosclerosis, contractile vascular smooth muscle cells (VSMCs) change to cells capable of migrating and proliferating to mediate repair, where the responses may be adaptive or mal-adaptive in effect. Cyclic adenosine monophosphate (cAMP)-elevating agents have been shown to inhibit migration of VSMC. cAMP activity within the cell is known to be ubiquitous and dynamic, requiring control through signal termination mechanisms for cellular homeostasis. Phosphodiesterase (PDE) enzymes are central to this critical regulatory process catalyzing the hydrolysis of cAMP. A great deal of insight into the role of PDEs in defining compartmentalization of cAMP signaling has arisen predominately from recent studies on the cAMP-specific PDE4 family. Compartmentalization of PDE4 is mediated by their unique N-terminal domains, which have been proposed to provide the “postcodes/zipcodes” for cellular localization. PDE4D isoforms vary widely, yet their conservation over evolutionary time suggests important non-redundant roles in distinct cellular processes. To study the potential role of individual PDE4D isoforms we seek to utilize the unique N-terminal targeting domains that are proposed to be responsible for their protein-protein interactions and site-directed localization. Herein, we report on the expression, targeting and localization of five “long” PDE4D isoforms and the impact on cell morphology of certain amino-terminal domains of individual PDE4D constructs expressing green fluorescent protein (NT-PDE4D/GFP) in human aortic smooth muscle cells (HASMCs). Through the development of engineered NT-PDE4D/GFP expression plasmids, we were able to study the cell biological impacts associated with the overexpression of individual PDE4D amino-terminal variants in HASMCs. We show that NT-PDE4D5/GFP and NT-PDE4D7/GFP expressing cells exhibited an elongated cell morphology, where this effect was much more marked in NT-PDE4D7/GFP expressing cells, exhibiting multiple leading edge structures and highly elongated “tails”. We identify a potential role for PDE4D7 targeting in the regulation of cell polarity and migration. Our results suggest the novel idea that PDE4D7, rather than the four other long PDE4D isoforms (PDE4D3, PDE4D5, PDE4D8, or PDE4D9), represents the dominant PDE4D variant involved in controlling cAMP-mediated effects on cell tail retraction dynamics. / Thesis (Master, Pathology & Molecular Medicine) -- Queen's University, 2014-03-13 13:00:31.684 / Video I: Time-lapse video of GFP-expressing cell migration in HASMC. GFP expressing cells did not differ in cell migration or morphology compared to non-injected control cells. HASMCs were microinjected with GFP construct. Representative images of micoinjected GFP cells were taken 24 h post-injection overnight at 30min intervals using a Zeiss Axiovert S100 microscope and processed as described in Materials & Methods. (10X) / Video II: Time-lapse video of NT-PDE4D7/GFP-expressing cell migration in HASMC. NT-PDE4D7/GFP expressing cells exhibit elongated tail and decrease in cell migration compared to non-injected control cells. HASMCs were microinjected with NT-PDE4D7/GFP construct. Particle tracking of NT-PDE4D7 cells showed cleaving and full detachment of elongated tail. Representative images of micoinjected NT-PDE4D7 cells were taken 24 h post-injection overnight at 30min intervals using a Zeiss Axiovert S100 microscope and processed as described in Materials & Methods. (10X)
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Defining a Model of Classical Activation in MicrogliaKena-Cohen, Veronique 24 February 2009 (has links)
Microglia, the resident immune cells of the central nervous system, can become activated following injury, disease, or infection. In vitro, they can be activated by stimuli, which determine the inflammatory phenotype they will develop. In this thesis, stimulating microglia with tumor necrosis factor- and interferon- resulted in classical activation, characterized by proliferation, increased transcription of complement receptor 3 and major histocompatibility class II molecules, and elevated production and transcription of interleukin-1 and nitric oxide. Stimulation with TNF and IFN also changed the intensity of phosphorylated (activated) cyclic adenosine monophosphate response element binding protein immunoreactivity in microglia. Specifically, cells differentiated into populations with high or low pCREB intensity. This was the first example of such a response in microglia and was representative of what occurred in vivo, after ICH. Thus, the characterization of this model will be useful for future studies of this and other intracellular pathways of classically activated microglia.
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Paslaugų kokybės vertinimas stovykloje „Gintaras“ / The evaluation of the service quality in „Gintaras“ campTrečiokaitė, Vytautė 06 September 2013 (has links)
Tyrimo objektas – paslaugų kokybės vertinimas. Tyrimo tikslas: įvertinti paslaugų kokybę stovykloje „Gintaras“. Uždaviniai: 1. Apibrėžti paslaugų kokybę ir jų vertinimą. 2. Apžvelgti stovyklų teikiamas paslaugas; 3. Nustatyti tikėtiną paslaugų kokybę “Gintaro” stovykloje. 1. Paslaugos kokybė, tai objekto savybė, kuri įgalina tenkinti šiandieninius arba tikėtinus vartotojo poreikius. Kokybei tirti taikomi įvairūs kokybės tyrimo modeliai, kurie organizacijoms leidžia nustatyti paslaugų kokybės problemas ir paskatina, bei padeda gerinti jų tikėtiną ar jau įvertintą paslaugų kokybę. 2. Pagrindinės paslaugos be kurių stovyklos organizatoriai negalėtų vykdyti savo veiklos yra apgyvendinimas ir maitinimas. Teikiamos stovyklų paslaugos vyksmas yra neįmanomas be vadovų, kurie atsakingi už stovykloje vykdomas programas, stovyklautojų laisvalaikį bei kitus užsiėmimus vykstančius stovykloje. 3. Norint gerinti paslaugų kokybę „Gintaro“ stovykloje, pirmiausiai dėmesį reikėtų atkreipti į stovykloje vykdomą programą, jos įvairumą, programos tinkamumą, jos pritaikymą skirtingiems vartotojams, bei svarbiausia – jos naudingumą vartotojui, kuris aktualus ir labai svarbus mūsų augančiai jaunajai visuomenei, jos požiūriui į bendravimą, rezultatų siekimą bei bendrą pasaulėžiūrą. / Study object: service quality evaluation. Goal of the work: to assess quality in „Gintaras“ camp. Tasks of the work: 1. Define the service quality conception and quality evaluation. 2. Overview camp services. 3. Evaluate service quality in „Gintaras“ campo of consumer attitudes. Conslusion: 1. Servise quality is an object feature which allows to satisfy today or anticipated consumer needs. To assess servise quality there are various quality testing models that enables organizations to determine the quality of service issues, and encourages helps to improve their expected quality of services. 2. Basic services that childrens camp can not be organized is accommodation and nourishment. Providing camp services, process is not possible without the camp leaders who are responsible for camp programs, the campers leisure and other activities taking place in the camp. 3. In order to improve service quality, in the "Amber" camp, first consideration should be given to the camp running program and its diversity, relevance of programs, and adapt to different users, and most importantly - the utility of the user that is relevant and very important for our growing young society and its approach to communication, achievement of results and overall outlook.
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DISC1 & GSK3β modulate PDE4 activity : functional integration of psychiatric associated signalling pathwaysCarlyle, Becky Catherine January 2010 (has links)
Following the discovery of the DISC1 gene in 2000, subsequent research has led to DISC1 becoming one of the most promising candidate genes for psychiatric disorders. Acting as a scaffold protein, DISC1 has a large number of interacting proteins and is involved in a series of intracellular signalling pathways. Amongst these binding proteins are two enzymes, PDE4 and GSK3β, that were originally implicated in psychiatric disease by virtue of their inhibition by psychoactive drugs. PDE4 enzymes are inhibited by rolipram, which possesses anti-depressant and anti-psychotic activity, while GSK3β is one of the major targets of lithium, a potent mood stabiliser. Both these enzymes are intricately involved in the PI3K/AKT, cAMP, and MAPK signalling pathways, all of which have a number of downstream outcomes with potential relevance to psychiatric disorders. The Millar and Porteous laboratory had established that DISC1 modulates PDE4 activity, but this predated awareness of GSK3 as another DISC1 interactor whose binding site overlapped with that of PDE4. Since cAMP is a key regulator of signalling pathways in the brain, I hypothesised that not only DISC1, but also GSK3β may be involved in the regulation of PDE4 activity to control local cAMP levels and gradients. To investigate this hypothesis, I characterised SHSY5Y cells as a model for measuring PDE4 activity, and performed a series of genetic and pharmacological manipulations on this system. Inhibition of GSK3β resulted in a decrease of basal PDE4 activity that was amplified by DISC1 overexpression. Wild type cells that were treated with forskolin exhibited a significant increase in PDE4 activity, which was suppressed by GSK3β inhibition and both overexpression and knockdown of DISC1. Further experiments confirmed that none of these changes were a result of differences in PDE4 mRNA or protein expression. Thus I have provided evidence that suggests tonic activation of PDE4 by GSK3β and evidence for modulation of PDE4 activity by DISC1. I provide evidence for the localisation of PDE4B & PDE4D with key psychiatric associated receptors in structures resembling developing dendritic spines; furthermore, agonism of NMDA receptors results in a significant increase in PDE4 activity in primary neurons. These results are a simple demonstration of an emerging principle in psychiatric research: that none of the signalling pathways implicated in psychiatric disease are acting in isolation. There are likely to be multiple points of integration between these pathways, with the demonstrated DISC1-GSK3β-PDE4 interaction forming one of these points. My results add an important new element to the understanding of how the DISC1 complex may regulate intracellular signalling in response to extracellular cues.
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Mechanisms of Na+ Homeostasis by Zebrafish (Danio Rerio) in Acidic WaterKumai, Yusuke 30 September 2013 (has links)
Zebrafish, Danio rerio, are able to survive exposure to extreme acidity (pH 4). Because previous studies demonstrated that disruption of ionic balance during exposure to acidic water is the major cause of mortality in acid-sensitive freshwater species, the focus of this thesis was to characterize the molecular mechanisms enabling zebrafish to maintain their Na+ homeostasis following exposure to acidic water. Initial findings (Chapter 2) demonstrated that branchial mRNA expression of selected isoforms of claudins, major components of tight junctions, are altered in an isoform-dependent manner, suggesting the potential regulation of epithelial permeability to minimize ion loss. Concurrently, a marked stimulation of Na+ uptake was observed in adults and larvae following acid-exposure. Because of the uniqueness of this response (increasing Na+ uptake in acidic water) among freshwater teleosts, the mechanisms related to Na+ uptake and its stimulation were investigated further (Chapters 3 - 7). Pharmacological treatments and gene knockdown approaches revealed that a functional metabolon consisting of an apically expressed Na+-H+-exchanger (NHE3b) in association with an apically expressed ammonia-conducting channel (Rhcg1), enables Na+ uptake in acidic water.
During chronic (>1 day) exposure to acidic water, cortisol (via glucocorticoid receptors) and catecholamines (via β-adrenergic receptors) are involved in stimulating Na+ uptake. Although catecholamines may act on both NHE3b and Na+-Cl- co-transporter (NCC), the effects of cortisol on Na+ uptake are mediated primarily by activation of NHE3b. On the other hand, during acute (<3 h) exposure to acidic water, cortisol does not appear to affect Na+ uptake; rather, the stimulation of Na+ uptake appears to be mediated by angiotensin II and catecholamines. Cyclic AMP (cAMP), a signalling molecule synthesized following the activation of β-adrenergic receptors, is critically involved in stimulating Na+ uptake, likely via activation of NHE3b and NCC. In agreement with this idea, ionocytes that express NHE3b also express high levels of β-adrenergic receptor (propranolol binding sites) as well as trans-membrane adenylyl cyclase (forskolin binding sites).
Taken together, the results of this thesis provide fresh insight into the mechanisms of osmoregulation in freshwater (FW) fish. In particular, the data reveal the presence of complex pathways regulating Na+ uptake in zebrafish exposed to acidic water. The relative importance of the various pathways depends in part on the duration of exposure; acute versus chronic.
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Empowering ExclusivityMunk, Julia 24 May 2013 (has links)
The segregation of disabled people is often perceived of as a form of oppression that acts as a means of exclusion from mainstream society. Disability rights activists and theorists have worked to end segregation as a form of oppression using the social model of disability and drawing on feminist theory. Feminist use of disengagement as a tool for empowerment is one component of feminist theory that has been left unexplored as it relates to disability. This work explores the role of segregation within the disability rights movement and within the development of the activist identity for disabled people. Based on the individual and collective experiences of six participants, all of whom are activists who attended segregated summer camps, I use a thematic analysis to reframe segregation as Empowering Exclusivity. This reframing has the potential to shift the strategic goals of the disability rights movement away from binary understandings of integration and segregation and towards a critical analysis of full inclusion and empowerment. / Graduate / 0700 / 0453 / julia.munk@gmail.com
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Die Rolle der Phosphodiesterase 2 im Herzen / The role of phosphodiesterase 2 in the heartLämmle, Simon 14 November 2014 (has links)
Herzinsuffizienz ist ein weltweites Gesundheitsproblem mit hoher Morbidität und Mortalität und immer
noch schlechter Prognose. Ein charakteristisches Merkmal der molekularen und damit verbundenen
strukturellen Veränderungen, die der terminalen Insuffizienz vorangehen ist die durch Desensitivierungsmechanismen
vermittelte Abnahme des beta-adrenergen (β-AR) Signalmoleküls zyklisches Adenosinmonophosphat
(cAMP) auf der einen Seite und der gleichzeitigen Zunahme des von natriuretischen Peptiden
(NP) und Stickstoffmonoxid (NO) generierten zyklischen Guanosinmonophosphat (cGMP) auf der
anderen Seite. Während hohe cAMP-Spiegel im Herzen als schädlich gelten, werden cGMP-abhängige
Signalkaskaden vorwiegend als protektiv verstanden. Amplitude, Lokalisation und Halbwertszeit beider
Signalmoleküle werden durch spezifische Enzyme, den Phosphodiesterasen (PDE) reguliert. Unter der
PDE-Superfamilie wird die Isoform PDE2 als einzige von cGMP aktiviert, um dann verstärkt cAMP abzubauen
und steht damit im Zentrum eines negativen Crosstalks dieser beiden Signalwege. PDE2 ist sowohl
in der humanen als auch der experimentellen Herzinsuffizienz hochreguliert und scheint dort am β-AR
Desensitivierungsprozess beteiligt zu sein. Im Rahmen dieser Arbeit wurde die pathophysiologische Rolle
der PDE2 im Herzen näher charakterisiert.
Es wird gezeigt, dass die PDE2 nicht nur in Kardiomyozyten, sondern auch in kardialen Fibroblasten
exprimiert wird. In Fibroblasten inhibieren cAMP/cGMP-Signalwege die Transformation von kardialen
Fibroblasten (CF) zu Myofibroblasten (MyoCF), einem zellulären Phänotyp, der unter anderem mit der
persistenten Fibrotisierung des erkrankten Herzgewebes in Verbindung gebracht wird. In CF führte eine
Überexpression von PDE2 zu eine starken Abnahme der basalen und β2-AR-vermittelten cAMP-Synthese
und war ausreichend, um in Abwesenheit exogener, pro-fibrotischer Stimuli die Transformation zum
MyoCF zu induzieren. In Übereinstimmung zeigten funktionale Analysen mit künstlich hergestelltem
Bindegewebe aus PDE2-überexprimierenden CF eine deutliche Zunahme der Gewebssteifigkeit. PDE2
übte keinen Einfluss auf basale oder durch das atriale NP generiertes cGMP aus und reduzierte nur partiell
die NO-induzierte cGMP-Akkumulation. Interessanterweise waren beide Stimuli in der Lage, trotz niedriger
cAMP-Spiegel die PDE2-induzierte CF-Transformation zum MyoCF zu verhindern und lassen daher
eine Redundanz dieser beiden sonst so gegensätzlichen Signalwege vermuten.
Zur Untersuchung von PDE2 in Kardiomyozyten wurde ein transgenes (TG) Mausmodell mit spezifischer
kardialer Überexpression herangezogen. Die Basalcharakterisierung zeigte eine erniedrigte Herzfrequenz
(HR) mit kompensatorisch erhöhter, basaler Kontraktionskraft, sowie eine verminderte Maximalantwort
bezüglich der HR nach akuter β-AR Stimulation. Auf molekularer Ebene war dieser Phänotyp mit einer
verminderten Phosphorylierung verschiedener β-AR Zielstrukturen wie Troponin I, Phospholamban und
Ryanodinrezeptor-2 assoziiert. Langzeitstudien belegten, dass eine Überexpression von PDE2 keine pathologischen
Konsequenzen hat, sondern im Gegenteil die durchschnittliche Lebensspanne der Tiere eher
verlängerte. Erste Studien im Herzinsuffizienzmodel der transversalen Aortenkonstriktion (TAC) zeigten
bisher eine beständig erniedrigte HR und verminderte Wanddicken bei allerdings vergleichbarer Abnahme
der kardialen Kontraktionskraft.
Trotz der klaren Befunde und neuen Erkenntnisse über die vielfältige Rolle der PDE2 im Herzen lässt sich
bisher noch nicht klar belegen, ob eine zusätzliche Aktivierung von myokardialen PDE2 tatsächlich im
Sinne einer intrazellulären β-AR-Blockade die Progression zur Herzinsuffizienz verlangsamen oder verhindern
könnte. Weitere darauf aufbauende Untersuchungen, wie z.B. eine akut induzierbare Aktivierung
bzw. Deaktivierung in experimentellen Herzinsuffizienzmodellen könnten den Weg für die Entwicklung
klinisch anwendbarer Ansätze zur therapeutischen Modulation dieser viel versprechenden Zielstruktur
ebnen.
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Defining a Model of Classical Activation in MicrogliaKena-Cohen, Veronique 24 February 2009 (has links)
Microglia, the resident immune cells of the central nervous system, can become activated following injury, disease, or infection. In vitro, they can be activated by stimuli, which determine the inflammatory phenotype they will develop. In this thesis, stimulating microglia with tumor necrosis factor- and interferon- resulted in classical activation, characterized by proliferation, increased transcription of complement receptor 3 and major histocompatibility class II molecules, and elevated production and transcription of interleukin-1 and nitric oxide. Stimulation with TNF and IFN also changed the intensity of phosphorylated (activated) cyclic adenosine monophosphate response element binding protein immunoreactivity in microglia. Specifically, cells differentiated into populations with high or low pCREB intensity. This was the first example of such a response in microglia and was representative of what occurred in vivo, after ICH. Thus, the characterization of this model will be useful for future studies of this and other intracellular pathways of classically activated microglia.
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Emotional and Social Developmental Benefits of Summer Camp for Children: Examining the relationship between social capital and emotional intelligenceCarruthers, Amanda Lee January 2013 (has links)
Camps provide an avenue for examining positive youth development. Camps represent environments where children can develop their social capital and emotional intelligence insofar as camp activities teach children how to build positive relationships and to relate to others emotionally that lead to positive outcomes. Little research has examined children’s social capital and emotional intelligence and the relationship between them. Using a longitudinal dataset, this study examined the change of social capital and emotional intelligence experienced by campers. Findings revealed that increases in social capital caused increases in emotional intelligence. Differences were found based on gender. Furthermore, residential camps were found to have a stronger effect on the relationship between social capital and emotional intelligence than day camps. This study lends itself to furthering the understanding of the development of emotional intelligence and the importance of camp in children’s development.
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Estudio comparado de la conducta nidificadora de los chimpancés ("Pan troglodytes schweinfurthii") de la comunidad de Kanyawara (Parque Nacional de Kibale, Uganda)Llorente Caño, Marina 21 January 2004 (has links)
El objetivo principal es el estudio exhaustivo de la conducta nidificadota de los chimpancés de Kanyawara, teniendo en cuenta una amplia lista de variables (sexo, edad, variaciones estacionales, características del hábitat.) que podrían incidir sobre la mencionada conducta. Se completa el trabajo con la colaboración de mapas de macro-distribución de los sitios de nidificación en el área de estudio y micro-distribución de los nidos en las zonas de descanso, así como con el seguimiento de la dinámica de reutilización.Finalmente, los resultados conseguidos se quieren comparar con otros estudios, sobre este comportamiento en grandes simios salvajes, con el fin de establecer semejanzas y diferencias ecológicas, sociales y/o culturales.La metodología utilizada es la usual en los trabajos etológicos de campo. El trabajo de campo va a suponer el seguimiento de la comunidad de chimpancés estudiada durante un año. El procedimiento empleado implicó el seguimiento diario (desde el amanecer hasta el crepúsculo) y el seguimiento de episodios nidificadores de los subgrupos de estudio, registrando sistemáticamente las conductas y variables relacionadas con la construcción de camas nocturnas y diurnas, además de la toma de medidas acerca de los nidos y de los sitios de anidaje conocidos, en ausencia de chimpancés, para su posterior análisis. Se presenta una amplia muestra, tanto por el número de nidos estudiados como por el número de episodios nidificadores nocturnos y diurnos observados.Entre las aportaciones de esta investigación cabe destacar el extenso y rico conjunto de datos descriptivos sobre la construcción de nidos de los chimpancés de la comunidad de Kanyawara.
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