This study explored the role of transient receptor potential melastatin 8 ion channels (TRPM8) in mechanisms of human glioblastoma (DBTRG) cell migration. Menthol stimulated influx of Ca2+, membrane current, and migration of DBTRG cells. Effects on Ca2+ and migration were enhanced by pre-treatment with hepatocyte growth factor/scatter factor (HGF/SF). Effects on Ca2+ also were greater in migrating cells compared with non-migrating cells. 2-Aminoethoxydiphenyl borate (2-APB) inhibited all menthol stimulations. RT-PCR and immunoblot analysis showed that DBTRG cells expressed both mRNA and protein for TRPM8 ion channels. Two proteins were evident: one (130-140 kDa) in a plasma membrane-enriched fraction, and a variant (95-100 kDa) in microsome- and plasma membrane-enriched fractions. Thus, TRPM8 plays a role in mechanisms that increase [Ca2+]i needed for DBTRG cell migration.

No description available.

The aim of this thesis is to determine the feasibility of an injectable delivery system based on 5-ethylene ketal ε-caprolactone for localized delivery of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) for treating critical limb ischemia. HGF and VEGF were chosen because of their ability to simultaneously stimulate the proliferation and migration of endothelial cells, to initiate the formation of blood vessels and the recruitment of pericytes to stabilize the blood vessels. Homopolymer of 5-ethylene ketal ε-caprolactone and its copolymer with D,L-Lactide were synthesized by ring opening polymerization using hydrophobic initiator (octan-1-ol) or an hydrophilic initiator (MPEG), and stannous octanoate as a co-initiator/catalyst. The resulting polymers were amorphous and viscous liquids at room temperature. The viscosity, biodegradation rate, and release rate were varied by copolymerizing with D,L-lactide and/or initiating with MPEG or octan-1-ol. In vitro, the polymers degraded with surface erosion characterized by a nearly linear mass loss with time with no significant change in number average molecular weight and glass transition temperature. The ratio of EKC to DLLA in the copolymer remained the same throughout the degradation studies. A similar degradation mechanism was observed in vivo when the copolymer initiated with octan-1-ol was implanted subcutaneously in rats. In vivo, the polymer exhibited a moderate chronic inflammatory response, characterized by the presence of neutrophils, macrophages, fibroblasts and fibrous capsule formation. The inflammatory response decreased with time but was still on going after 18 weeks of subcutaneous implantation. Protein release from the polymer was transported by convection through the hydrated polymer region, at a rate determined by the osmotic pressure generated and the hydraulic conductivity of the polymer. Highly bioactive VEGF and HGF were released in a sustained manner, without burst effect for over 41 days when delivered simultaneously, using the osmotic release mechanism. VEGF was released at the rate of 36 ± 7 ng/day for 41 days, while HGF was released at the rate of 16 ± 2 ng/day for 70 days. Factors that influenced release of proteins were their solubility in the concentrated trehalose solution and hydraulic permeability of the polymer. This delivery system can serve as a potential vehicle for controlled release of VEGF and HGF for treating critical limb ischemia or the controlled release of other proteins for other clinical applications. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2012-05-23 10:18:48.307

Purpose – The presented research aims to explain, describe and analyze the process of dynamic strategy development in high growth firms. Accordingly the research seeks to investigate how dynamic strategies are used within high growth firms and how strategic learning affects the process. Design/methodology/approach – The authors presents a review of theoretically relevant studies of high growth related to strategy, and two original studies examining the impact of dynamic strategy on high growth. A theoretical framework for the study of dynamic strategy processes is developed. The study comprehends eight interviews divided over five high growth firms, where high growth is defined by the OECD (2008) standard. Findings – In the study, the researchers finds significant evidence for the active and deliberate use of dynamic strategy in the high growth firms of the study. The implication of strategic learning on the dynamic strategies is found to be substantial. The findings shows that dynamic strategy development are used to a large extent and considered vital for achieving growth within in the high growth firms of the study. Research/theoretical implications/limitations – The findings demonstrate that dynamic strategy development is actively used in high growth phases of the firms studied. This has implications on the extension of previous research, as it shows the actual use of dynamic strategy and further emphasizes the importance of strategic learning within this process. With the important limitation that the study is considered too small to generalize over a larger population, which implies that further research on the subject is needed. Managerial implications – The findings provide guidelines for managers of how to handle strategy development in high growth, however due to the previous limitation this is presented as the way the high growth firms within this study handles this development. The guidelines could be used by anyone in managerial positions, thus increasing the understanding of how high growth firms handle strategy.

La thérapie cellulaire constitue une stratégie prometteuse dans le traitement de l'infarctus du myocarde. Afin de mieux contrôler la survie, la différenciation et l'intégration des cellules greffées, nous avons tenté une approche d'ingénierie tissulaire en associant les cellules à un microvecteur comportant une surface biomimétique et pouvant libérer un facteur de croissance (FC), les microcarriers pharmacologiquement actifs (MPA). Parmi les cellules utilisées dans une telle approche, les cellules souches adultes dérivées du tissu adipeux (ADSC) ne soulèvent pas de problèmes d'ordre éthique et permettent de réaliser des greffes autologues. Ces cellules sont largement étudiées pour la régénération de nombreux tissus en vertu de leurs propriétés immuno-modulatrices, de leur capacité à sécréter des FC et chémokines, mais également de leur large potentiel de différenciation. Dans une première étape, nous avons étudié l'effet des molécules de la matrice extracellulaire et des MPA sur la différentiation en cardiomyocytes des ADSC en présence d'un cocktail de FC. Nous avons ainsi pu observer que l'apport du cocktail de FC permettait aux cellules de s'engager dans la voie de différentiation cardiaque après 2 semaines. En comparant l'effet de la laminine (LM) et de la fibronectine sur cette différentiation, nous avons pu observer que la LM permettait d'induire une différentiation dans une cellule plus mature et que ceci était potentialisée par un enrichissement du milieu en TGF!1. Finalement, l'apport de MPA recouverts de LM favorisait une différentiation plus rapide des cellules en présence du cocktail. Les MPA peuvent également libérer un facteur de croissance de manière prolongée au cours du temps. Par conséquent, nous avons encapsulé 3 protéines, le VEGF, le HGF et l'IGF-1, et d'étudier leur effet sur les comportement des ADSC. Nous avons ainsi pu observer que des MPA libérant du HGF et de l'IGF-1 induisaient une différenciation de ADSC dans la voie cardiaque et que cette différentiation était également observée lorsque les complexes ADSCMPA étaient intégrés dans un hydrogel thermosensible. Cependant, nous avons aussi observé que la quantité de protéines libérées à partir des MPA était plus faible dans le gel. Nous avons donc cherché dans une dernière partie à améliorer le profile de libération des protéines à partir des MPA en changeant la composition du polymère. Nous avons ainsi utilisé différents copolymères triblock PLGA-PEG-PLGA pour formuler des microsphères et évaluer leur rôle sur la libération de la protéine mais aussi sur la stabilité de celle-ci durant la dégradation du polymère.

L’HGF/SF (Hepatocyte Growth Factor/Scatter Factor) est le ligand du Récepteur Tyrosine Kinase (RTK) MET. Ce couple ligand-récepteur joue un rôle essentiel dans de nombreux processus biologiques tels que l’embryogenèse, la régénération tissulaire et l’angiogenèse. Comme pour de nombreux RTK, la dérégulation de l’activité de MET est associée à la progression et l’invasion tumorales. Bien que le récepteur MET ait été intensivement étudié au cours de ces dernières décennies, les processus moléculaires conduisant à son activation par l’HGF/SF restent encore mal connus et controversés.NK1, un variant naturel de l’HGF/SF, comprenant la partie N-terminale (N) et le premier domaine kringle (K1) de l’HGF/SF, possède une activité agoniste. En effet, NK1 dimérise spontanément en position « tête-bêche » et est considéré aujourd’hui comme la structure minimale permettant la dimérisation de MET et son activation. Afin de déterminer leur contribution respective, les domaines N et K1 isolés ont été produits par voie recombinante et ne montrent aucune ou qu’une très faible activité agoniste respectivement. Une présentation monovalente de ces domaines au récepteur MET ne semble donc pas pertinente pour déterminer leur fonction.Par conséquent, nous avons souhaité générer des complexes multivalents mimant le positionnement des domaines N et K1 au sein du dimère naturel. En tirant partie de la « One-Pot SEA ligation » développée au laboratoire, ces domaines ont été synthétisés par voie chimique et fonctionnalisés avec une extrémité C-terminale biotinylée (NB et K1B). En utilisant la streptavidine (S) comme plateforme de multimérisation, nous avons généré des complexes semi-synthétiques NB/S et K1B/S et déterminé les propriétés biologiques de ces nouvelles constructions multivalentes.L’ensemble des analyses de signalisations cellulaires et phénotypiques démontre sans équivoque que le complexe K1B/S est capable de mimer les réponses biologiques induites par l’HGF/SF et son variant NK1. De plus, le complexe K1B/S, injecté dans la circulation systémique, déclenche la signalisation de MET dans le foie. L’utilisation de ce complexe K1B/S nous a permis de démontrer que deux domaines K1, correctement assemblés et orientés, constituent l'interface minimale et suffisante requise pour déclencher une pleine activation de MET. A l’inverse, les premières données fonctionnelles ont démontré que le complexe NB/S ne lie pas directement MET mais utilise les héparanes sulfates comme pont moléculaire.Ces études utilisant de nouvelles configurations structurales pourraient donc servir de modèle de base au développement de nouveaux agonistes de MET dans le cadre de thérapies régénératives ou préservatrices, mais aussi d’antagonistes dans le cadre de thérapies anticancéreuses ciblées. / Hepatocyte Growth Factor/Scatter Factor (HGF/SF) and its receptor tyrosine kinase (RTK) MET play an essential role in embryogenesis, tissue regeneration and angiogenesis. As observed for many others RTK, MET is also strongly involved in tumor progression and invasion mechanisms. Although numerous biological and structural approaches have been focused on the molecular processes leading to MET activation by HGF/SF, the HGF/SF-MET interaction framework remains only partially understood due to the complexity of the multivalent ligand-receptor binding events.NK1, a naturally occurring splice variant of HGF/SF, comprising the N-terminal part and the first kringle domain (K1) of HGF/SF, exhibits a partial agonistic activity toward MET. Indeed, in presence of heparan sulfates, NK1 self-associates into a “head-to-tail” dimer and is considered as the minimal structural module able to trigger MET dimerization and activation. Nevertheless, the individual role of N and K1 domains in the dimerization/activation of MET remain elusive.Stimulated by the conviction that monomeric N and K1 domains are not suitable for studying the functioning of HGF/SF-MET, we produced, by total chemical synthesis, biotinylated analogs of the N and K1 domains (NB and K1B). By combining with streptavidin (S), we engineered the semisynthetic constructs NB/S and K1B/S in order to determine the biological properties of these new multivalent architectures of N and K1 domains.In vitro, as observed with HGF/SF or NK1, we show that the K1B/S complex is able to fully activate MET signaling cascades to promote scattering, morphogenesis and survival phenotypes in various cell types. Even more, the K1B/S complex stimulates angiogenesis in vivo and, when injected systemically, triggers MET signaling in the liver. The use of this K1B/S complex allows us to demonstrate that two K1 domains, correctly assembled and oriented, constitute the minimal unit for sufficient MET activation. In contrast, first in vitro data have demonstrated that NB/S complex does not bind directly MET as previously thought, but rather, uses heparan sulfates as a molecular bridge.We envision these new structural configurations serving as a template for both the rational design of potent MET agonists (e.g. using K1B/S for regenerative therapies) and antagonists (e.g. using NB/S for targeted cancer therapies).

Flash is the unwanted or excessrubber material that presents on the outersurface of themolded rubber product. This will affect the surface finish; it is a cosmetic defect andit can be removed. It forms because of the leak or the excess molded rubber materialbetween the surface of the mold, typically on the parting line, (Jordan Anderson,2014). The presence of flash will reduce customer satisfaction. There are manymethods to remove the flash. The method is selected according to the degree of flashextension and the location where it occurs.The project aims to design a semi/full automated machine, which helps for having asmooth and fine surface finish of the weight plates. These plates are made up of rubberfor the ELEIKO group. The weight plates have different weights from 10 to 20 kg,but the diameter of each plate stays the same, but the thickness will be different foreach plate. The machine should be designed that removes all the excess rubber andshould smoothen the outer surface of the weight. The purpose of this work is to gainknowledge about different product development methods, respective tools, andtechniques that are used. The machine should be user- friendly, should not becomplicated, should not damage the workpiece (marks or trace of the blade), shouldnot put the employer in danger, and economically feasible.This report presents the progress of designing of the product, product development,methods, and literature study. The designed model can construct in the industry fortheir problem they are faced by the flash. The model is very simple and unique so thateveryone can perform the task without any previous experience. Material alternativeswere evaluated as well as manufacturing possibilities. The designed machine was theoffered for free as means for further research and development. Keywords: flashing, additive manufacturing, Ullman method, Pugh matrix, rubberweight plates, lever arm, smoothening tool.

The aim of this study is to investigate the relation between venture capital and the number of high growth firms. Previous research has covered the relation at the firmlevel where the positive effect of venture capital on innovation, firm growth and economic growth has been established. However, the research field have been lacking a more aggregated approach. With a fixed effects panel regression with the number of high growth firms as the dependent variable and the amount of venture capital as the key independent variable, this study is conducted at the country-level with a panel of 20 countries. The study yield no significant results except the positive effect of GDP per capita. The conclusion is that the data available today is not ready for this level of aggregation as it captures to much noise with regards to other factors affecting firm growth in a country. Growth in employment might also be an outdated proxy to measure firm growth as today's modern firms are not as dependent on a large number of employees to scale as in the past. / Målet med denna studie är att undersöka relationen mellan riskkapital och snabbväxande företag. Tidigare studier har undersökt relationen på företagsnivå där riskkapitalets positiva effekt på innovation, firmatillväxt och ekonomisk tillväxt har påvisats. Dock har forskningsfältet saknat ett tillvägagångssätt på en mer aggregerad nivå. Med en fixed effects-modell applicerad på paneldata med en beroende variabel bestående av antalet snabbväxande företag och en oberoende variabel bestående av mängden riskkapital, undersöks relationen på landnivå med ett urval av 20 länder. Studien visar inga signifikanta resultat bortsätt från kontrollvariabeln BNP per capita som är positiv och signifikant. Slutsatsen i arbetet är att den data som finns tillgänglig idag inte är mogen för studier på en aggregerad landnivå då brus i form av andra faktorer som påverkar snabbväxande företag i ett land fångas upp. Företagstillväxt mätt i tillväxt i antalet anställda i ett företag kan även vara en föråldrad metod. Dagens moderna företag präglade av affärsmodeller som inte kväver arbetskraft för att skala upp verksamheten på samma sätt som företag traditionellt gjort historiskt.

Objectifs: Hepatocyte Growth Factor (HGF) améliore la régénération axonale et la survie des motoneurones lors du développement embryonnaire. Son rôle dans la régénération des nerfs périphériques lésés chez l’adulte n’a pas encore été étudié. Notre objectif est de déterminer l’expression de HGF dans la moelle épinière murine suite à une axotomie, avec ou sans stimulation électrique, directe ou transcutanée. Méthodes: Soixante souris C57BL/6 adultes ont été divisées en 5 groupes : Contrôle (n=12), Placebo (n=12), Axotomie (n=12, lacération et réparation immédiate du nerf sciatique), Directe (n=12, lacération, réparation immédiate et stimulation électrique directe proximale du nerf sciatique, 1h, 20 Hz) et Transcutanée (n=12, lacération, réparation immédiate et stimulation électrique transcutanée proximale du nerf sciatique, 1h, 20 Hz). Les moelles épinières ont été recueillies 1, 3, 7 et 14 jours suivant l’intervention. L’expression de HGF a été évaluée par technique d’hybridation in situ. Résultats: Nos résultats démontrent une augmentation de l’expression de HGF dans les moelles épinières murines suite à l’axotomie. Cette augmentation est plus rapide suite à la stimulation électrique, autant directe que transcutanée. L’expression de HGF devient localisée aux zones motrices de la moelle épinière murine dans les groupes Axotomie, Directe et Transcutanée. Conclusions: HGF, facteur neurotrophique impliqué de le développement et la survie des motoneurones, a une expression altérée suite à la lacération du nerf sciatique. Ceci suggère fortement qu’il participe aussi à la régénération des nerfs moteurs. De plus, l’expression plus rapide de HGF suite à la stimulation électrique suggère son implication dans l’augmentation de la régénération nerveuse. / Purpose: Hepatocyte Growth Factor (HGF) plays a role in promoting axonal growth and survival of motoneurons during embryonic development. This factor might also be important in directing the regeneration of adult motoneurons following laceration. We aim to identify the expression patterns of HGF following axotomy, with or without direct or transcutaneous electrical nerve stimulation in a mouse model. Methods: Sixty adult C57BL/6 mice were divided into 5 groups: Control (n=12), Sham (n=12), Axotomy (n=12, sciatic nerve laceration and immediate repair), Direct (n=12, sciatic nerve laceration, immediate repair and application of direct electrical stimulation on the proximal nerve end, 1h, 20 Hz) and Transcutaneous (n=12, nerve laceration and immediate repair followed by proximal transcutaneous electrical stimulation, 1h, 20 Hz). Spinal cords were harvested at 1, 3, 7 and 14 days post-surgery. The expression patterns of HGF were measured using in situ hybridization. Results: Our results showed an upregulation of HGF expression in mouse spinal cords following sciatic nerve axotomy. This occurred more quickly following electrical stimulation in both Direct and Transcutaneous groups. The expression pattern of HGF became localized to the motor neuron pools in the Axotomy, Direct and Transcutaneous groups. Conclusions: HGF, a growth factor involved in directing the outgrowth of motor axons in development, has an altered expression pattern following sciatic nerve laceration, suggesting it may also play a role in directing motoneuron regeneration. Furthermore, rapid change in the expression pattern of HGF following electrical stimulation suggests it may also be involved in the upregulation of nerve regeneration following electrical stimulation.

Since its beginning, graft rejection remains the key problem of solid organ transplantation. This reaction of the recipient's immune system against mismatched antigens of the transplanted organ causes graft damage and consequently loss of its function. Rejection involves cellular (lymphocyte mediated) and humoral (antibody mediated) mechanisms. Among the genetic factors which may have a prognostic value in rejection risk evaluation are the Human Leukocyte Antigens (HLA) genotype, the Killer Immunoglobuline-like Receptor (KIR) gene repertoir, cytokine and other gene polymorphisms. These factors could be screened for before transplantation to find the best possible combination of genetic characteristics of the donor and recipient and to reveal patients with "risky" genotypes, who may need more intensive immunosuppression and more careful post-transplant follow-up. Molecular factors, such as HLA and non-HLA antibodies, soluble CD30 molecule (sCD30), Hepatocyte Growth Factor (HGF) and other cytokines, measured before and/or after transplantation in the recipient's blood may be helpful for rejection risk estimation and may also be used as post-transplant rejection onset markers. In our study, we focused on some of the above mentioned factors. We found that ethnicity plays a significant role in the...