Thesis (doctoral)--University of Jyväskylä, 1994. / Thesis is based on six separately published papers which are reprinted at end. Includes bibliographical references.

Thesis (doctoral)--University of Jyväskylä, 1994. / Thesis is based on six separately published papers which are reprinted at end. Includes bibliographical references.

A musculatura estriada de cães Golden Retriever, jovens e adultos, provenientes do Canil GRMD-Brasil, foram analisadas sob microscopia de luz. Para tanto, foram coletadas amostras do músculo bíceps femoral de um cão adulto não-acometido e um acometido por distrofia muscular, e dos músculos bíceps femoral, semitendinoso, diafragma e miocárdio ventricular esquerdo de dois cães jovens acometidos, as quais foram coradas pelas técnicas de hematoxilina-eosina, tricrômico de Masson e sirius red F3BA. Todos os músculos examinados do cão adulto e dos jovens portadores de distrofia apresentaram lesões musculares. As lesões observadas na musculatura esquelética de todos os cães acometidos incluíram: perda de organização das fibras musculares, variação no diâmetro das fibras, aumento do tecido conjuntivo perimisial e endomisial, este no animal adulto. As lesões eram mais evidentes no animal adulto. O diafragma apresentou fibras hipercidófilas, com contorno mais definido; necrose envolvendo grupos de fibras musculares; espessamento do conjuntivo perimisial e edema endomisial. A musculatura da língua mostrou variação do diâmetro das fibras; fibrose perimisial e infiltração de tecido adiposo no epimísio. No miocárdio identificou-se leve a moderada fibrose e aumento do espaço endomisial. Nossos achados demonstram as lesões produzidas por essa patologia na musculatura esquelética, comparativamente com a musculatura de animais não-acometidos e corroboram o descrito para cães acometidos por distrofia muscular, GRMD, de outros criatórios / The striated muscle of young and adults Golden Retriever dogs, from the GRMD-Brazil Kennel, had been analyzed under light microscopy. Samples of biceps femoral muscle of a healthy control adult dog and of an adult Golden Retriever muscular dystrophy (GRMD), and of the femoral, semitendinosus, biceps femoral, diaphragm, and left ventricular myocardium muscles of two young GRMD had been collected to be stained with HE, Masson trichrome and sirius red F3BA stain. All the examined muscles of the adult and young GRMD had presented muscular injuries. The injuries observed in the skeletal musculature included: dearrangement of muscular fibers, variation in the fiber diameter, increase of the perimisial and endomisial connective tissue, the latter in the adult dog. The lesions were more evident in the adult GRMD. The diaphragm presented hyperacidophyly fibers, with more defined contour; necrosis involving groups of muscular fibers; increase of perimisial connective tissue and endomisial edema. The tongue musculature showed variation of the fibers diameter; perimisial fibrosis and fat infiltration in the epimysial space. In the myocardium it was identified moderate fibrosis and increase of the endomysial space. Our findings demonstrate the injuries produced for this pathology in the skeletal musculature, comparatively with the healthy control dog, and corroborate that described for GRMD of other GRMD-kennels

Nous avons généré des souris déficientes pour les gènes codant pour les échangeurs Na/Ca de type I (NCX1) et de type III (NCX3) afin d'étudier, in vivo, le rôle de ces deux protéines.<p>L‘analyse phénotypique des souris adultes totalement déficientes pour le gène Ncx1 (Ncx1-/-) n'a pu être menée étant donné que ces souris décèdent au cours du développement embryonnaire.<p>Les souris déficientes pour le gène Ncx3 (Ncx3-/-) sont viables et fertiles. Nous avons analysé l'effet de l'inactivation du gène Ncx3 dans le muscle squelettique et plus particulièrement au niveau de la jonction neuromusculaire.<p>L'analyse histologique des muscles squelettiques de souris Ncx3-/- a révélé des altérations des fibres musculaires caractérisées par la présence de foyers de fibres nécrotiques et d'infiltrats de cellules mononuclées.<p>L'analyse électromyographique classique a montré un électromyogramme anormal du muscle gastrocnémien de souris Ncx3-/-, révélant une affection neuromusculaire pré- et post-synaptique caractérisée par (i) la petitesse de l'amplitude de la réponse M au repos, (ii) le décrément après stimulation répétitive à basse fréquence, (iii) l'incrément après stimulation répétitive à haute fréquence et (iv) la facilitation post-exercice. L'électromyographie à fibre unique a révélé une MCD élevée et des blocages anormaux de la transmission neuromusculaire, reflétant une atteinte post-synaptique de la jonction neuromusculaire chez les souris Ncx3-/-. L'ensemble de ces anomalies électromyographiques sont les caractéristiques du syndrome myasthénique de Lambert-Eaton.<p>Finalement, pour déterminer les conséquences de l'inactivation du gène Ncx3 sur l'activité physique des souris Ncx3-/-, nous avons réalisé des tests comportementaux sur ces souris. Ces tests ont permis de détecter un épuisement et une faiblesse musculaire accrus à l'effort chez ces souris.<p>En conclusion, nos observations montrent que les souris Ncx3-/- présentent des anomalies électromyographiques similaires à celles du syndrome myasthénique de Lambert-Eaton. Ces résultats suggèrent que l'échangeur NCX3 est peut-être impliqué dans la pathogenèse de certaines formes de cette maladie.<p>Des études supplémentaires afin de confirmer notre hypothèse devront donc être réalisées.<p>/<p>We produced and analyzed mice deficient for Na/Ca exchanger 3 (NCX3), a protein which mediates cellular Ca2+ efflux (forward mode) or Ca2+ influx (reverse mode) and thus controls intracellular Ca2+ concentration. NCX3-deficient mice (Ncx3-/-) present a skeletal muscle fiber necrosis and a defective neuromuscular transmission, reflecting the absence of NCX3 in the sarcolemma of the muscle fibers and at the neuromuscular junction. The defective neuromuscular transmission is characterized by the presence of electromyographic abnormalities including low compound muscle action potential amplitude, a decremental response at low frequency nerve stimulation, an incremental response and a prominent post-exercise facilitation at high frequency nerve stimulation as well as neuromuscular blocks. The analysis of quantal transmitter release in Ncx3-/- neuromuscular junctions revealed an important facilitation superimposed on the depression of synaptic responses and an elevated delayed release during high frequency nerve stimulation. It is suggested that Ca2+ entering nerve terminals is cleared relatively slowly in the absence of NCX3, thereby enhancing residual Ca2+ and evoked and delayed quantal transmitter release during repetitive nerve stimulation. Our findings indicate that NCX3 plays an important role in vivo in the control of Ca2+ concentrations in the skeletal muscle fibers and at the neuromuscular junction.<p> / Doctorat en sciences biomédicales / info:eu-repo/semantics/nonPublished

Les ions Ca2+ responsables de la contraction musculaire sont extrudés du réticulum sarcoplasmique (RS) via le récepteur de la ryanodine de type 1 (RyR1). Des mutations du gène de RyR1 sont responsables chez l’homme de l’hyperthermie maligne (HM) et de la myopathie à cores centraux (MCC). Nous avons caractérisé les altérations de l’efflux calcique du RS dues à de telles mutations dans la fibre musculaire de souris par électrophysiologie et imagerie confocale. L’expression des formes Y523S, R615C et R2163H de RyR1, associées à l’HM, provoque une hypersensibilité de l’efflux vis-à-vis du potentiel membranaire alors que les formes I4897T et G4896V associées à la MCC provoquent une réduction chronique de l’efflux sans modification de densité des RyR1 s ainsi que des protéines Cav1.1 et SERCA1. L’expression de la forme R4892W associée à la MCC ne modifie pas l’efflux calcique suggérant une plus faible pénétrance fonctionnelle de cette forme. Dans tous les cas, aucune indication de changement du contenu en calcium RS n’a été observée. Les résultats suggèrent que les modifications pathologiques de l’efflux calcique sont la conséquence directe de l’altération de fonction des canaux. Le deuxième objectif du travail s’est intéressé au rôle de certains phosphoinositides (PtdInsPs) dans la régulation de l’efflux calcique du RS. La surexpression de la PtdInsPs-phosphatase Mtm 1 n’a aucun effet sur l’efflux calcique alors que l’application intracellulaire de ses deux principaux substrats inhibe l’efflux, suggérant que leur accumulation dans les fibres musculaires déficientes en Mtm1 pourrait contribuer aux altérations pathologiques associées du couplage excitation-contraction / Ca2+ ions that trigger muscle contraction are released from the sarcoplasmic reticulum (SR) through the type 1 ryanodine receptor (RyR1) channel. Mutations of the gene encoding RyR1 are responsible for malignant hyperthermia (MH) and central core disease (CCD) in human. We characterized the alterations of SR Ca2+ release due to such mutations in mouse fibers using electrophysiology and confocal imaging. Expression of each of the MH-associated Y523S, R615C and R2163H mutant forms of RyR1 increases the sensitivity of Ca2+ release to membrane potential whereas forms I4897T and G4896V that are associated to CCD provoke a chronic depression of Ca2+ release with no concurrent alteration of RyR1, Cav1.1 and SERCA1 density. Expression of the CDD-associated R4892W form of RyR1 has no effect on Ca2+ release suggesting a weaker functional penetrance of this mutant form. In all cases we found no indication for a change in SR calcium content. Results suggest that pathological changes in Ca2+ release are the direct consequence of the functional alteration of the channels. The second goal of this work focused on the role of certain phosphoinositides (PtdInsPs) in the control of SR Ca2+ release. Over-expression of the PtdInsPs-phosphatase Mtm 1 does not affect Ca2+ release whereas intracellular application of its two main substrates inhibits Ca2+ release, suggesting that accumulation of these molecules in Mtm 1-deficient fibers could contribute to the associated alterations of excitation-contraction coupling

No description available.

No description available.

Abstract not available

路易士‧卡洛爾的《愛麗絲夢遊記》(Alice in Wonderland, 1865) 及《穿越明鏡》(Through the Looking-Glass, 1871) 是十九世紀極為出名的兒童文學。兩本書中都描述一位名為愛麗絲的女孩如何進入一個奇幻的國度而展開旅程，以及當中她所遇見的各種角色。這兩本書不只豐富有趣，更充滿了諧擬以及邏輯和文字遊戲，使其成為現今許多學者研究的對象。但是，兩本書的相似性使得一般讀者或是學者在閱讀時，都將其視為同一則故事。然而，在仔細探索後，會發現卡洛爾在寫作過程中，很明顯地把兩本書做了區分。本論文因此試圖將兩本書進行比較分析，來重新檢視兩個奇幻世界以及兩個愛麗絲的差異性。 本文第一章為概論，簡單介紹卡洛爾及其兩本作品。第二章運用德勒茲和加達利的概念，針對仙境與鏡中世界的空間的進行比較。從文本例證中可看出，第一本書中的仙境近似一個「平滑空間」(smooth space)，而第二本中的鏡中世界則如同一個「褶縐空間」(striated space)。此差異性更凸顯了這兩段故事的不同。第三章主要應用透納的理論來探討主角愛麗絲與兩個空間的關係。透納利用范‧杰內普的「儀式理論」(rites of passage)發展出「閾限」(liminality)的觀念，並用此觀念來解讀正在進行生命儀式的個體以及其所屬的階段。許多學者認為兩段故事是在描述愛麗絲長大的過程，因此她的旅程可被視為她經歷生命儀式─成年禮的歷程。然而，雖然兩本書中的兩個空間均可被視為一種「閾限空間」(liminal space)，但只有鏡中世界塑造了一個成功的生命儀式，使愛麗絲在最後得以達到象徵性的成年。另一方面，由於仙境中缺乏線性進展，無法構成一個有效的生命儀式，導致第一本書中的愛麗絲到最後還是以小孩之姿結束在此空間的旅程。第四章援引兩位學者的文章來探討愛麗絲在兩個空間中身體呈現的差異以及和愛麗絲自我發展的相關性。由於愛麗絲在仙境中維持一個小孩的身分，她的身體與行為不會造成社會的威脅，在空間中也就不會受任何拘束。反之，在愛麗絲即將長大的鏡中世界中，其女性的身體卻必須受到限制。因此，在鏡中世界的愛麗絲不僅身體未出現任何變化，她的任何身體的慾望也必須受到克制。這與在第一本書中的身體再現是全然迥異的。第五章則是本文的結論；總結這兩本書的差異性，而身為讀者的我們也應正視其中的區別，進而能夠更加了解卡洛爾筆下的兩個奇幻世界以及兩位均名為愛麗絲的主角。 / Lewis Carroll’s Alice in Wonderland and Through the Looking-Glass have brought laughter to children as they journey with Alice through the fantasy worlds ever since their first publication in the 19th century. Filled with Carroll’s witty parodies and plays of logic, the books quickly become two of the most widely studied children fantasies. Both books are about a little girl named Alice who crosses a barrier and enters a fantastical dream world, in which she meets a variety of strange creatures. With the similarity of structures, the two books are often regarded as one single work in modern days. However, upon close examination, it is quite evident that the two works are of entirely different entities, and should be read accordingly. In my thesis, I explore the possibility of reading the books separately by comparing and contrasting Carroll’s creation of the two worlds, as well as the two different developments of Alice within the books. In chapter one, I give an overall summary of the author and a brief introduction of the background of the Alices. Chapter two focuses on the two spaces of Wonderland and Looking-Glass World. Using Gilles Deleuze and Félix Guattari’s notion of smooth and striated space, this chapter delineates how Wonderland is more like a smooth space with its rhizomatic routes and a lack of center, whereas the linearity of Looking-Glass World appears to be closer to a striated space. This critical difference highlights the individualization between the two worlds. Chapter three investigates the relationship between Alice and the two spaces by adopting Victor Turner’s concept. Drawing on Arnold van Gennep’s notion of the rites of passage, Turner proposes the concept of liminality, which is the state of an individual when he or she is undergoing a rite of passage. Most scholars suggest that both Alice books depict Alice’s development to adulthood, which makes Alice’s journeys through the two worlds rites of passage. However, while both spaces can be said to be liminal spaces for Alice, only Looking-Glass World constitutes a completed rite of passage for her, in which she reaches a symbolic maturity at the end. With no linear progression, Wonderland fails to be a rite of passage, and hence Alice comes out still as the child she is going in. Chapter four concentrates on the bodily manifestation of Alice, and how they relate to the difference in Alice’s self development in the two books. Drawing on Donald Rackin’s and Anna Krugovoy Silver’s articles, I find that Alice’s exuberant bodily manifestation and vigorous expression of bodily desires in Wonderland is due to the fact that Alice remains a young child, and that her immature body does not cause a threat to the Victorian society. Hence, Carroll allows her to be the fully embodied girl in the first book. In Looking-Glass World, in which Alice is on the verge of growing up, her body must be restrained. Thus, her body stays static and her bodily desires are contained, very different from the bodily representation in the first book. In Wonderland and Looking-Glass, Carroll has created two very enchanting stories, with two distinctive fantasy worlds and two separate developments of Alice. Conclusively, I believe that Carroll meant for them to be treated as two separate books, with two different spaces of the dream worlds and two protagonists by the name of Alice.

Im Mittelpunkt dieser Arbeit standen Signaltransduktionsprozesse in den Strukturen der Kraftübertragung quergestreifter Muskelzellen, d. h. in den Costameren (Zell-Matrix-Kontakten) und den Glanzstreifen (Zell-Zell-Kontakten der Kardiomyozyten).<br><br>Es ließ sich zeigen, dass sich die Morphologie der Zell-Matrix-Kontakte während der Differenzierung von Skelettmuskelzellen dramatisch ändert, was mit einer veränderten Proteinzusammensetzung einhergeht. Immunfluoreszenz-Analysen von Skelettmuskelzellen verschiedener Differenzierungsstadien implizieren, dass die Signalwege, welche die Dynamik der Fokalkontakte in Nichtmuskelzellen bestimmen, nur für frühe Stadien der Muskeldifferenzierung Relevanz haben können. Ausgehend von diesem Befund wurde begonnen, noch unbekannte Signalwege zu identifizieren, welche die Ausbildung von Costameren kontrollieren: In den Vorläuferstrukturen der Costamere gelang es, eine transiente Interaktion der Proteine Paxillin und Ponsin zu identifizieren. Biochemische Untersuchungen legen nahe, dass Ponsin über eine Skelettmuskel-spezifische Insertion im Carboxyterminus das Adapterprotein Nck2 in diesen Komplex rekrutiert. Es wird vorgeschlagen, dass die drei Proteine einen ternären Signalkomplex bilden, der die Umbauvorgänge der Zell-Matrix-Kontakte kontrolliert und dessen Aktivität von mitogen activated protein kinases (MAPK) reguliert wird.<br><br>Die Anpassungsvorgänge der Strukturen der Kraftübertragung an pathologische Situtation (Kardiomyopathien) in der adulten quergestreiften Muskulatur wurden ausgehend von einem zweiten Protein, dem muscle LIM protein (MLP), untersucht. Es konnte gezeigt werden, dass ein mutiertes MLP-Protein, das im Menschen eine hypertrophe Kardiomyopathie (HCM) auslöst, strukturelle Defekte aufweist und weniger stabil ist. Weiterhin zeigte dieses mutierte Protein eine verringerte Bindungsfähigkeit an die beiden Liganden N-RAP und alpha-Actinin. Die molekulare Grundlage der HCM-verursachenden Mutationen im MLP-Gen könnte folglich eine Veränderung der Homöostase im ternären Komplex MLP &ndash; N-RAP &ndash; alpha-Actinin sein. Die Expressionsdaten eines neu generierten monoklonalen MLP-Antikörpers deuten darauf hin, dass die Funktionen des MLP nicht nur für die Integrität des Myokards, sondern auch für die der Skelettmuskulatur notwendig sind. / The cell-matrix-contacts (costameres) and cell-cell-contacts (intercalated discs of cardiomyocytes) of cross-striated muscle cells transmit mechanical forces to the exterior. On top of this mechanical function, both structures have been implied to be involved in signal transduction processes.<br><br>Dramatic morphological changes in the overall structure of cell-matrix-contacts of skeletal muscle cells were revealed during differentiation. Moreover, this reorganisation was accompanied by alterations in protein composition. Immunofluorescence microscopy indicated that signalling pathways which control the dynamics of focal contacts in non-muscle cells seem to be important only for early differentiation stages of skeletal muscle cells. To explore novel signalling pathways involved in regulating the formation of costameres, signalling molecules engaged were identified. Thus, paxillin and ponsin transiently interact at the precursors of costameres during muscle development. In addition, biochemical data indicate that a skeletal muscle specific module in the carboxyterminal part of ponsin can recruit the adapter protein Nck2 to this complex. Hence, the three proteins might form a ternary signalling complex involved in controlling the reorganisation of cell-matrix-contacts. Apparently, the activity of this signalling complex is regulated by mitogen activated protein kinases (MAPK).<br><br>A second approach has focussed on adaptational processes of the same structures observed in pathological situations. In particular, the role of muscle LIM protein (MLP) in hypertrophic cardiomyopathy (HCM) was investigated. It was shown that a HCM-causing mutant MLP protein fails to fold properly and that the consequent loss of stability is reflected in altered binding properties: the mutant MLP protein shows decreased binding to both N-RAP and alpha-actinin. Hence, the molecular basis for HCM-causing mutations in the MLP gene might be an altered homeostasis of the ternary complex MLP &ndash; N-RAP &ndash; alpha-actinin. Increasing evidence indicates that the functions of MLP are required not only for the integrity of the myocardium. In addition, MLP seems to have regulatory functions in skeletal muscle tissues.