The shunt from the cyclooxygenase to lipoxygenase pathway in human osteoarthritic subchondral osteoblasts is linked with a variable expression of the 5-lipoxygenase-activating protein

Osteoarthritis (OA) is characterized by articular cartilage degradation and hypertrophic bone changes with osteophyte formation and abnormal bone remodeling. Two groups of OA patients were identified via the production of variable and opposite levels of prostaglandin E(2 )(PGE(2)) or leukotriene B(4 )(LTB(4)) by subchondral osteoblasts, PGE(2 )levels discriminating between low and high subgroups. We studied whether the expression of 5-lipoxygenase (5-LO) or 5-LO-activating protein (FLAP) is responsible for the shunt from prostaglandins to leukotrienes. FLAP mRNA levels varied in low and high OA groups compared with normal, whereas mRNA levels of 5-LO were similar in all osteoblasts. Selective inhibition of cyclooxygenase-2 (COX-2) with NS-398-stimulated FLAP expression in the high OA osteoblasts subgroup, whereas it was without effect in the low OA osteoblasts subgroup. The addition of PGE(2 )to the low OA osteoblasts subgroup decreased FLAP expression but failed to affect it in the high OA osteoblasts subgroup. LTB(4 )levels in OA osteoblasts were stimulated about twofold by 1,25-dihydroxyvitamin D(3 )(1,25(OH)(2)D(3)) plus transforming growth factor-β (TGF-β), a situation corresponding to their effect on FLAP mRNA levels. Treatments with 1,25(OH)(2)D(3 )and TGF-β also modulated PGE(2 )production. TGF-β stimulated PGE(2 )production in both OA osteoblast groups, whereas 1,25(OH)(2)D(3 )alone had a limited effect but decreased the effect of TGF-β in the low OA osteoblasts subgroup. This modulation of PGE(2 )production was mirrored by the synthesis of COX-2. IL-18 levels were only slightly increased in a subgroup of OA osteoblasts compared with normal; however, no relationship was observed overall between IL-18 and PGE(2 )levels in normal and OA osteoblasts. These results suggest that the shunt from the production of PGE(2 )to LTB(4 )is through regulation of the expression of FLAP, not 5-LO, in OA osteoblasts. The expression of FLAP in OA osteoblasts is also modulated differently by 1,25(OH)(2)D(3 )and TGF-β depending on their endogenous low and high PGE(2 )levels

L'étude du "cross-talk" des voies de synthèse des prostaglandines E₂ et des leucotriènes B₄ dans le fonctionnement altéré des ostéoblastes sous-chondraux humains arthrosiques

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Thinking and Doing: Challenge, Agency, and the Eudaimonic Experience in Video Games

The nascent growth of videogames has led to great leaps in technical understanding in how to create a functional and entertaining play experience. However, the complex, mixed-affect, eudaimonic entertainment experience that is possible when playing a video game—how it is formed, how it is experienced and how to design for it, has been investigated far less than hedonistic emotional experiences focusing on fun, challenge and ‘enjoyment.’ Participants volunteered to be interviewed about their mixed-affect emotional experiences of playing avant-garde videogames. New conceptions of agency emerged (Actual, Interpretive, Fictional, Mechanical) from the analysis of transcripts and were used to produce a framework of four categories of agency. This new framework offers designers and researchers the extra nuance in conversations around agency, and contributes to the discussion of how we can design video games that allow for complex, reflective, eudaimonic emotional experiences

Phenomenology of Neutrino Oscillations

This review is focused on neutrino mixing and neutrino oscillations in the light of the recent experimental developments. After discussing possible types of neutrino mixing for Dirac and Majorana neutrinos and considering in detail the phenomenology of neutrino oscillations in vacuum and matter, we review all existing evidence and indications in favour of neutrino oscillations that have been obtained in the atmospheric, solar and LSND experiments. We present the results of the analyses of the neutrino oscillation data in the framework of mixing of three and four massive neutrinos and investigate possibilities to test the different neutrino mass and mixing schemes obtained in this way. We also discuss briefly future neutrino oscillation experiments.Comment: 109 pages. Final version to be published in Progress in Particle and Nuclear Physics, Volume 43. Typos correcte

Social Media as part of Online-Marketing-Mix : Webpresence of one premium brand (Rolex) and non-premium brand (Swatch) in the social network Facebook

Die vorliegende Arbeit beschäftigt sich mit den neuen Nutzungsmöglichkeiten des Web 2.0, die eine menschliche Kommunikation mit Interaktion zulassen. Durch die rasanten Zuwachsraten von Social Media gewinnt das weltweit größte Social Network Facebook auch als Marketingkanal für Unternehmen eine immer größere Bedeutung. In einer vergleichenden Fallstudie der Premiummarke Rolex und Non-Premiummarke Swatch werden die jeweiligen Facebook Fanpages hinsichtlich der Markenaktivitäten und der Resonanz der Kunden untersucht. Die aufgestellte These der Auswirkung auf eine positive Kaufentscheidung einer Facebook Präsenz wird empirisch anhand einer Umfrage mit 136 Swatch Kunden und 45 Rolex Kunden validiert. Die Ergebnisse der Untersuchung werden abschließend in einem Fazit zusammengefasst

L'étude du "cross-talk" des voies de synthèse des prostaglandines E₂ et des leucotriènes B₄ dans le fonctionnement altéré des ostéoblastes sous-chondraux humains arthrosiques

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal