Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Collagenose.
Thèses sur le sujet « Collagenose »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleures thèses pour votre recherche sur le sujet « Collagenose ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les thèses sur diverses disciplines et organisez correctement votre bibliographie.
1
LAFON, BENOIT. "Collagenoses de l'adulte associees a des cancers : association fortuite ou syndrome paraneoplasique ?" Amiens, 1993. http://www.theses.fr/1993AMIEM046.
Texte intégral
2
Manka, Szymon W. "Interaction between triple-helical collagens and human collagenases." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6817.
Texte intégralRésumé :
Collagens are the major structural proteins in animal tissues. Their degradation is essential in embryogenesis and development, while unbalanced collagen breakdown is seen in diseases such as arthritis, atherosclerosis and cancer. Fibril-forming collagens I, II and III consist of three polypeptide chains forming a triple helix, which is resistant to cleavage by most proteases. Collagenases of the matrix metalloproteinase family (MMP-1, MMP-8, and MMP-13) degrade fibrillar collagens by locally unwinding the helix, followed by cleavage into ¼ and ¾ fragments. They comprise two domains, the catalytic (Cat) domain and the hemopexin (Hpx) domain, which are connected via a flexible linker. Both domains are essential for collagenolysis, but the exact sites of collagenase-collagen interactions and how they unwind collagen remain elusive. This thesis addresses the roles of individual collagenase domains, and the sites in both the enzyme and the substrate that are involved in collagen binding and unwinding, focusing on the fibril-forming collagens and human MMP-1 as a prototype. MMP-1 bound to immobilised collagen I with markedly higher affinity than its Hpx domain alone. The Cat domain alone failed to bind to collagen, but in the full-length enzyme it participated in collagen binding. Above 25°C the two- domain binding involved the catalytic site cleft. Triple-helical peptide (THP) Toolkits of collagens II and III were screened for MMP-1 binding, and the collagenase binding motif has been established. It contains two hydrophobic residues within a 9 residue distance. Finally, hydrogen/deuterium exchange mass spectrometry (H/DXMS) experiments indicated two potential collagen binding sites: 285-316 and 349-365 in the Hpx domain, and suggested a possibility of a dynamic interaction of the collagenase N-terminus with collagen. These results imply that the two domains of collagenase bind to collagen in a cooperative manner. Based on the THP binding and H/DXMS data a 3D model of collagenase-collagen interaction has been proposed. It assumes that collagenase utilises hydrophobic interactions to unwind the collagen helix via perturbation of the hydrogen-bond network which stabilises the helix.
3
MERIGEAU, BENATAR KARINE. "Etude structure/fonction d'un fragment de collagene et de la collagenase d'hypoderma lineatum." Paris 6, 1996. http://www.theses.fr/1996PA066623.
Texte intégralRésumé :
Le collagene represente 25% des proteines chez les mammiferes et seules les collagenases, qu'elles appartiennent a la famille des metalloproteases ou des proteases a serine, sont capables de le couper dans les conditions physiologiques. Parmi les 19 types de collagenes caracterises a ce jour, le collagene de type vi, compose de trois chaines polypeptidiques 1, 2 et 3, est le seul a former des filaments dits perles par un processus d'autoassociation remarquable. Nous avons etudie par cristallographie le fragment c5 du domaine globulaire c terminal de la chaine polypeptidique 3 du collagene de type vi qui presente 40% d'identite l'appi (amyloid- protein precursor inhibitor). La structure cristallographique de ce fragment c5 a ete resolue par remplacement moleculaire a la resolution de 1,6a puis affinee en utilisant des facteurs de temperature anistropes (shelxl-93) a 1,2a de resolution. Le facteur d'accord final est de 13,6% pour 10762 reflexions superieure a 4. La structure tridimensionnelle montre un repliement appartenant a la famille des inhibiteurs de proteases a serine de type kunitz. Des tests biochimiques ont montre que le fragment c5 ne possede pas d'activite inhibitrice envers les proteases a serine. Sur la base de la structure tridimensionnelle, nous avons propose quelques mutations permettant de restaurer l'activite inhibitrice. Des travaux recents de mutagenese dirigee realises sur un triple mutant asp, thr, phe ont confirme la validite de nos hypotheses. La deuxieme partie de cette these a ete consacree a l'etude de la collagenase (pm 25000 da) d'hypoderma lineatum. Elle est extraite du varon parasite du betail responsable de l'hypodermose. Lorsque nous avons aborde ce travail, aucun substrat ni inhibiteur synthetique n'etait connu. Nous avons caracterise deux substrats synthetiques, ce qui nous a permis de mettre en evidence trois inhibiteurs synthetiques. Par ailleurs, nous avons demontre les proprietes auto-inhibitrice de la collagenase due a la presence d'un coude (31-44) qui peut penetrer dans le site actif. Le dodecapeptide synthetique correspondant a cette structure secondaire a ete synthetise et son activite inhibitrice demontree. Par ailleurs, des anticorps polyclonaux produits contre ce peptide reconnaissent la collagenase. Nous avons clone la collagenase d'hypoderma lineatum dans e. Coli permettant ainsi une etude de mutagenese dirigee.
4
Abreu, Sara Priscila Lopes de. "Collagenase for biotechnology applications." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15507.
Texte intégralRésumé :
Mestrado em Biologia Molecular e Celular<br>Collagen is an abundant protein in all animals and is the main component of numerous tissues, having also structural and regulatory roles. Collagen can be found in various numerous locations presenting specific functions, such as the establishment of the cellular shape, its strength and structural integrity, and is also involved in tissue maintenance. Moreover, collagen has an important role in the formation of the extracellular matrix of the connective tissue, by contributing to its physical properties. Collagenases are enzymes, more specifically metalloproteinases, with a zincbinding domain. These enzymes are able to digest the triple helical region of native collagen, cleaving its peptide bonds. In recent years, bacterial collagenases have been gaining interest for industry proposes, by offering a variety of applications. In the clinical area, collagenases are used as therapy for diseases associated with excessive deposition of collagen, as for example, in patients suffering from Dupuytren’s disease. The enzymes can also be used to help the debridement of wounds and burns, and also for cancer gene therapy applications. The objective of this work is the comparison and optimization of two methods of recombinant collagenase purification, evaluating which method provides the most cost-effective purification. For that purpose, a simple and high resolution method for purification of histidine-tagged recombinant protein was used. Immobilized metal ion affinity chromatography (IMAC) with a Ni Sepharose 6 Fast Flow, through a column HisTrap FF 1ml or in batch were used. Results obtained through protein quantification by densitometry technique, showed that the purification using a column has higher yield. By zimography was possible determine the gelagenolytic activity of ColAh, and was also possible quantify the collagenolytic activity of ColAh, using a synthetic peptide N-(3-[2-Furyl]acryloyl)-Leu-Gly-Pro-Ala (FALGA). Obtained results also showed that the obtained recombinant protein is stable to storage over time and when submitted to different temperatures (room temperature; 4°C; -20°C).<br>O colagénio é uma proteína abundante em todos os animais, exercendo funções estruturais e reguladoras. Está presente em diversos locais e executa funções específicas, nomeadamente na manutenção dos tecidos e na conservação da sua estrutura celular, da sua força e integridade estrutural. Possui uma elevada importância na formação da matriz extracelular do tecido conjuntivo ao contribuir para as suas propriedades físicas. Colagenases são enzimas, mais especificamente metaloproteinases, com um característico domínio de ligação a zinco característico Atualmente, as colagenases bacterianas possuem diversas aplicações industriais. Por exemplo, na clínica são utilizadas no tratamento de doenças associadas a acumulação excessiva de colagénio, como a Doença de Dupuytren, no desbridamento de queimaduras e feridas e também em terapia génica oncológica. O objetivo deste trabalho é a comparação e a otimização de dois métodos de purificação, para avaliar qual dos processos será mais rentável. Para tal, foi utilizado um método de purificação de proteínas recombinantes, que foram marcadas com histidinas, utilizando um método de cromatografia de afinidade com ião metálico imobilizado (IMAC). Para comparação, a purificação foi estabelecida utilizando um método em coluna, HisTrap FF e um método em batch. Os resultados obtidos através da quantificação de proteína, usando técnica de quantificação por densitometria demonstraram que a purificação quando realizada por coluna, apresenta maior rendimento. Através de ensaios realizados posteriormente foi possível demonstrar a atividade da ColAh por zimografia de gelatina, e quantificar a atividade colagenolitica contra o péptido sintético N-(3-[2-Furyl]acryloyl)-Leu-Gly-Pro-Ala (FALGPA). Os resultados também demonstram que a proteína recombinante apresentou estabilidade, quando armazenada ao longo do tempo, a diferentes temperaturas (temperatura ambiente; 4°C; -20°C).
5
Romanelli, Raquel G. "Activation of neutrophil collagenase in periodontitis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0022/MQ40756.pdf.
Texte intégral
6
Brüning, Adrian Rudolf Nicolaus Ernst. "A polarimetric method for collagenase activity measurement." Thesis, Rhodes University, 1992. http://hdl.handle.net/10962/d1004113.
Texte intégralRésumé :
A polarimetric method for monitoring the rate of soluble collagen breakdown by collagenase enzyme action has been developed. The method represents an extension of previous physicochemical techniques based on viscometry, but is simpler and easier to carry out, particularly in the case of reaction rate studies. The method was developed arising from reports of collagenase activity measurement on inappropriate substrates such as gelatin, modified collagens and synthetic polypeptides. The optical method depends on measurement of the loss in optical rotation in solutions of soluble calfskin collagen resulting from initial enzymic cleavage of the collagen trip1e-helix, followed by spontaneous unwinding of the resultant unstable helical fragments. Specific assay conditions were chosen to ensure that the loss in optical rotation following enzymic cleavage was rapid and complete. The method is specific since in the absence of collagenase, non-specific proteinases produce only a limited decrease in solution optical activity. The method has also been compared with established physicochemical assay techniques and compares favourably with both viscometric and titrimetric collagenase assays. The availability of a rapid, sensitive and quantitative procedure for measurement of collagenase activity provides a convenient means for detecting the presence of collagenase in solution and examination of hide bacterial cultures for collagenase production. In addition, a study of biocidal compounds of potential interest in hide preservation for possible inhibitory effects on collagenase is conveniently carried out with the method. Fundamental research into synergistic action in enzymic hydrolysis of collagen is now possible, providing valuable insight into the mechanism of raw hide biodeterioration.
7
CARBONNEL, LUC. "Association d'une colite collagene et d'une sprue collagene : a propos d'un cas." Aix-Marseille 2, 1990. http://www.theses.fr/1990AIX20302.
Texte intégral
8
Mansell, Jason Peter. "The collagenous matrix in osteoporosis." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282570.
Texte intégral
9
Mehta, Bhavya Chandrakant. "Optimization of enzyme dissociation process based on reaction diffusion model to predict time of tissue digestion." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1142575553.
Texte intégral
10
TROTTE, NICOLE. "Le collagenome eruptif : a propos d'un cas avec etude ultrastructurale." Angers, 1988. http://www.theses.fr/1988ANGE1009.
Texte intégral
11
Patterson, Margaret Lucy. "The collagenolytic mechanism of the collagenases." Thesis, University of East Anglia, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390640.
Texte intégral
12
Lai, Jim Yuan. "MT1-MMP in neutrophils, potential mechanism for collagenase activation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0020/MQ53414.pdf.
Texte intégral
13
Macdonald, Christopher David. "Synergistic transcriptional regulation of collagenase gene expression in chondrocytes." Thesis, University of Newcastle upon Tyne, 2013. http://hdl.handle.net/10443/1941.
Texte intégralRésumé :
The proteolytic degradation of articular cartilage in load-bearing joints is a key pathological step in the progression of arthritis, a process mediated by enzymes called collagenases (specifically MMP-1 and MMP-13). My research has focused on the transcriptional regulation of these enzymes in cartilage cells (chondrocytes) in response to a pro-catabolic stimulus which mimics the complex milieu of elevated cytokines found within the arthritic joint. Activating Protein (AP)-1 transcription factors, specifically the c-Fos/c-Jun heterodimer, have previously been shown to be crucial in collagenase gene regulation. c-Fos/c-Jun gene expression, protein production and collagenase promoter enrichment studies identified a temporal deficit between transient c-Fos/c-Jun peak following 1 hour stimulation and the initiation of collagenase gene transcription following 6 hours stimulation. Protein synthesis inhibitor studies indicated that although c-Fos/c-Jun are indeed important, they are not the sole regulators of collagenase gene expression. DNA microarray studies highlighted a number of genes that contributed to transcriptional regulation early within this temporal deficit. Collagenase gene expression was assessed following the siRNA-mediated silencing of these factors. This confirmed that new factors, not previously associated with collagenase gene regulation, were demonstrated to have a significant role in initiating their transcription. This included factors such as activating transcription factor (ATF)3 and early growth response (EGR)2 which demonstrated differential regulation of the collagenase genes, with their silencing affecting MMP13 expression alone. Having identified a number of contributing factors, I then assessed their temporal gene expression and protein production. Comparisons to c-Fos/c-Jun induction confirmed that a number of these factors were transient, similar to AP-1, yet they peaked following longer durations of stimulation. Subsequent siRNA gene silencing of c-Fos and c-Jun led to decreased expression of some of these factors. This demonstrated that these factors may be regulating collagenase expression indirectly by controlling the expression of other transcription factors that, themselves contribute to the regulation of collagenase gene. The present study improves our understanding of how collagenases are regulated in chondrocytes in response to pro-catabolic stimuli. With an improved knowledge of regulation it may be possible to specifically abrogate aberrant collagenases expression in disease. Moreover, by exploiting the differential regulation of collagenases exhibited by some of these factors, there is the potential to mitigate the side effects associated with broad-spectrum collagenase inhibition, thereby removing the barrier to successful treatment.
14
RACLOT, GILLES. "Prostanoides, colites collagene et lymphocytaire." Besançon, 1992. http://www.theses.fr/1992BESA3036.
Texte intégral
15
MONNET, EMMANUEL. "Interactions plaquettes-collagene. Mise en evidence d'une nouveau recepteur specifique du collagene de type iii." Paris 7, 2000. http://www.theses.fr/2000PA077260.
Texte intégralRésumé :
De nombreuses etudes ont montre que les plaquettes interagissaient avec le collagene du sous endothelium de la paroi vasculaire lesee, via des recepteurs membranaires : gpia/iia, gpiv, gpvi, p65. Cependant leurs roles exacts sont mal definis. Dans la premiere partie de ce travail, nous comparons le role de gpia/iia dans les differentes phases de l'activation plaquettaire induites par le collagene de type i et de type iii. Nous montrons que ce recepteur est plus specifiquement implique dans l'etalement et l'agregation plaquettaire induites par le collagene de type i. De plus, nous mettons en evidence son role secondaire dans l'activation plaquettaire induite par le collagene de type iii. Notre travail se tourne ensuite plus specifiquement vers ce dernier collagene. Une sequence octapeptidique situee dans le fragment cb4 de la chaine 1(iii) a ete prealablement decrite comme inducteur de l'adhesion et inhibiteur de l'agregation plaquettaire induite par le collagene de type iii. Ici, nous identifions le recepteur de cette sequence. C'est une proteine de 68/72 kda, appelee tiiicbp, qui est differente des autres recepteurs du collagene deja decrits. Les anticorps monoclonaux developpes contre cette proteine, tout comme l'octapeptide, inhibent le contact, l'adhesion en conditions statiques et dynamiques et l'agregation plaquettaire induits par le collagene de type iii. Ils sont sans effets sur l'activation plaquettaire induite par le collagene de type i. D'un autre cote, nous montrons que les anticorps anti-tiiicbp reconnaissent la surface des plaquettes, des monocytes, des lymphocytes, des granulocytes et des erythrocytes. Ce recepteur est egalement exprime par les fibroblastes et les cellules endotheliales mais pas par les cellules musculaires lisses. Cette these presente un nouveau recepteur, tiiicbp, implique dans l'activation des plaquettes par le collagene de type iii lors de la formation du thrombus. De plus, sa presence a la surface des cellules de l'inflammation suggere un role pour tiiicbp dans ce processus.
16
Chen, Yizhu. "Characterization of semi-purified collagenase fraction from lobster (Homarus americanus)." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60654.
Texte intégralRésumé :
A collagenolytic enzyme fraction was isolated from the hepatopancreas of the lobster (Homarus americanus) and semi-purified by the successive steps of acetone precipitation, ammonium sulfate fractionation, ion exchange chromatography on Mono Q column, followed by gel filtration on a Superdex 75 column or by preparative isoelectric focusing using a Rotofor cell.<br>Semi-purified collagenase fractions from the lobster hepatopancreas was electrophoresed in polyacrylamide gels both in the presence or absence of SDS, and shown to have molecular weights ranging from 15,000-66,000. The enzymatically active peak 1 fraction from the isoelectric focusing step in the Rotofor cell migrated as a single band in 12% polyacrylamide gel with few light protein bands.<br>The pH-activity data indicated that the collagenase fraction had two pH optima for the hydrolysis of native collagen, one at pH 4 and the other between pH 7-8.<br>The temperature-activity data for the hydrolysis of native collagen indicated the lobster enzyme exhibited two temperature optima--a minor one at 25$ sp circ$C and a more pronounced one between 40$ sp circ$C and 50$ sp circ$C.
17
Knupp, Carlo. "Molecular packing in network forming collagens." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251361.
Texte intégral
18
Chapuis, Jean-François. "Les lattices de collagene : etude biomecanique." Besançon, 1992. http://www.theses.fr/1992BESA3716.
Texte intégral
19
Noreen, Razia. "FTIR imaging of collagens in gliomas." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14316/document.
Texte intégralRésumé :
Le gliome est le type le plus agressif et mortel de tumeur cérébrale. Ces tumeurs se caractérisent par la présence conjointe de phénotypes solides (de bas grade, moins invasif, hautement vascularisé) et diffus (haut grade, très envahissant et diffus) des glioblastomes multiformes. Les collagènes sont des composants majeurs de la MEC des cellules tumorales des gliomes, et sont également présents dans la membrane basale des vaisseaux sanguins, mais avec une composition différente entre vasculatures saine et tumorale. L'abondance et la typologie des collagènes dans la MEC des cellules tumorales et la vasculature représentent donc un marqueur potentiel de diagnostic pour la gradation des tumeurs gliales. Nous avons développé la spectro-imagerie infrarouge à transformée de Fourier pour déterminer les modifications morphologiques et moléculaires apparaissant dans les formes solides et diffuses de gliomes, ainsi que dans les vasculatures saine et tumorale. Nous avons d'abord mis en évidence les vasculatures saine et tumorale en utilisant des nanoparticules injectées dans le système sanguin. Ensuite, nous avons appliqué des méthodes de reconstruction spectrale pour distinguer les tissus sains vs. ceux des formes solide et diffuse de tumeurs sur la base de leurs contenus en collagène de la MEC. Enfin, nous avons déterminé les changements de types du collagène au cours de la progression tumorale, validant ainsi la notion que l’analyse de ces contenus est potentiellement un marqueur diagnostic pour la gradation des gliomes<br>The glioma is the most aggressive and lethal type of brain tumor. Such tumor is characterized both by solid (low grade, less invasive, highly vascularized) and diffuse (high grade, very invasive and diffuse) phenotypes in high-grades. Collagens are major components of ECM in glioma tumor cells, and are also present in basement membrane of blood vessels in vasculature, but with different composition between healthy and tumor capillaries. The abundance and typology of collagens in tumor cell ECM and vasculature is thus a potential diagnostic marker for grading glioma tumors. We developed Fourier transform infrared (FTIR) spectro-imaging as a functional technique to determine the morphological and molecular changes occurring in solid and diffuse form of tumor tissues as well as in healthy and tumor vasculatures. We first highlighted healthy and tumor vasculatures using nanoparticles injected in blood system. Then, we applied curve-fitting methods to distinguish between healthy tissue vs. solid and diffuse tumor tissues on the basis of the collagen contents found in ECM. Finally, we determined collagen typology changes during tumor progression, thus validating that collagen contents analysis is potentially a diagnostic marker for glioma grading
20
Cox, Jennifer H. "Neutrophil collagenase (matrix metalloproteinase-8) : regulatory roles in inflammation and autoimmunity." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/5247.
Texte intégralRésumé :
Inflammation is an essential process in wound healing and for the elimination of invading
pathogens. However, unregulated inflammation can lead to numerous pathologies including
autoimmunities, tumorigenesis, and atherosclerosis. Matrix metalloproteinases (MMPs),
once thought to be only extracellular matrix degrading enzymes, are now known to be key
regulators of inflammatory and immune responses through proteolysis of bioactive
molecules. MMP-8, a neutrophil-specific MMP, is protective in skin cancer models where
MMP-8 knockout mice have an initial delay in neutrophil infiltration followed by a massive
accumulation at the site of treatment. We investigated this delay in a murine air pouch
model of acute inflammation, where MMP-8 deficiency caused decreased neutrophil
migration in response to LPS. This was attributed to MMP-8 processing and activation of
LPS-inducible CXC chemokine (LIX), a murine neutrophil chemoattractant. Indeed, MMP-8
knockout mice had normal neutrophil infiltration in response to synthetic analogs of cleaved
LIX. Furthermore, homologous pathways with human chemokines CXCL5 and CXCL8 were
described. In vivo, an indirect interaction between MMP-8 and LIX also occurs, whereby
MMP-8 processes and inactivates cLl-proteinase inhibitor causing increased neutrophil
elastase activity, which then efficiently cleaves and activates LIX. MMP-8 was protective in a
model of rheumatoid arthritis where synovial tissues from MMP-8 deficient mice had an
abundance of neutrophils. This prolonged neutrophil accumulation correlated with a loss of
caspase-1 1 expression, consequent decreased caspase-3 activity and reduced apoptosis.
MMP-8 shedding of TNF-a was also decreased in MMP-8 deficient leukocytes, potentially
dampening a key apoptotic pathway in neutrophils. The role of MMPs in processing the Thi
cell CXCR3-binding chemokines CXCL9, CXCL1O, and CXCL11 was investigated. The
leukocytic MMPs -7, -8, -9, and -12 cleaved CXCL11 at both the amino and carboxy
terminus. N-terminal cleavage resulted in the conversion of a receptor agonist to antagonist
whereas C-terminal cleavage by MMP-8 caused a significant loss in glycosaminoglycan
binding, demonstrating for the first time that direct chemokine proteolysis can regulate the
formation of haptotactic gradients. Therefore, MMP-8 is a pivotal regulator in the onset and
termination of inflammation, and has multifaceted roles in innate and acquired immunity as
well as the autoimmune disorder rheumatoid arthritis.
21
Meisenzahl, Christina. "Regulation der Metalloproteinasen Stromelysin und Collagenase durch Interferon in retinalen Pigmentepithelzellen." Doctoral thesis, [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963923110.
Texte intégral
22
Pickering, K. "Histochemical study of collagenous structures present in food." Thesis, University of Leeds, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376366.
Texte intégral
23
Smerling, Christiane. "Integrin α2β1-mediated cellular interactions with collagenous ligands". Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612315.
Texte intégral
24
Chen, Ling. "Characterization of Non-collagenous Proteins in Vertebrate Mineralization." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1405950378.
Texte intégral
25
Molloy, Kevin John. "The role of collagenases in atherosclerotic plaque instability." Thesis, University of Leicester, 2004. http://hdl.handle.net/2381/29472.
Texte intégralRésumé :
The primary aim of this thesis was to quantify the collagenase concentrations in carotid plaques and to relate them to markers to plaque instability.;Recent studies have shown that strain therapy decreases cardiovascular risk, even in patients with normal cholesterol levels. A further aim of this thesis was to observe the effects of statins on clinical and biochemical indicators of plaque instability.;Atherosclerotic plaques were collected from 159 patients undergoing carotid endarterectomy. The presence and timing of carotid territory symptoms was ascertained. Pre-operative embolisation was recorded by transcranial Doppler. Each plaque was assessed for histological features of instability. Plaque MMP and cytokine concentrations was quantified using ELISA.;Significantly higher concentrations of active MMP-8 were observed in the plaques of symptomatic patients (p=0.0002), emboli-positive patients (p=0.0037) and in those plaques demonstrating histological evidence of rupture (p=0.0036). No differences were seen in the levels of MMP-1 and MMP-13. Immunohistochemistry, in situ by hybridisation and colocalisation studies confirmed the presence of MMP-8 protein and mRNA within the plaque, which colocalised with macrophages. These data suggest that the active form of MMP-8 may be partly responsible for degradation of the collagen cap of atherosclerotic plaques. This enzyme represents an attractive target for drug therapy aimed at stabilising vulnerable plaques.;Patients on statins were less likely to have suffered symptoms in the month prior to surgery (p=0.0049) and less likely to have cerebral embolisation detected (p=0.0459). Carotid plaques retrieved from statin-taking patients, revealed significantly lower concentrations of MMP-9 (p=0.0018) and IL-6 (p=0.0005). These data suggest that statins may stabilise plaques by lowering MMP and cytokine levels, resulting in decreased embolisation and symptoms.
26
Delmond, Christine Liquière. "La colite collagène et les pathologies associées." Montpellier 1, 1988. http://www.theses.fr/1988MON11225.
Texte intégral
27
DUTEL, FRANCOIS. "La sprue collagene : etude d'une observation personnelle." Amiens, 1988. http://www.theses.fr/1988AMIEM114.
Texte intégral
28
Iredale, John Peter. "Tissue inhibitor of metalloproteinase-1 expression by human hepatic lipocytes and its role in liver disease." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295679.
Texte intégral
29
Wong, Kayleigh. "Identification and Targeting of Collagen in the Capsule of Rat Knees with Immobilization-Induced Flexion Contractures." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32269.
Texte intégralRésumé :
Immobility causes joint contractures, loss in range of motion (ROM), notably in elderly and bed-ridden patients. In a rat knee immobilization flexion contracture (FC) model, the posterior capsule contributes to irreversible limitation of ROM. Through microarray, extracellular matrix and collagen pathways were identified as differentially expressed in the posterior capsule of knees with FC. We hypothesized that intra-articular injection of collagenases in rats with knee FC will interfere with collagen in the capsule and allow increased ROM. After four weeks of hind-limb immobilization, rats develop knee FC; two weeks of remobilization with collagenase treatment showed increased ROM compared to buffer injected knees of 8.043° (p-value=0.046). Histological analysis of knee sections revealed changes in collagen content of the extracellular matrix in posterior capsule. In vitro incubation of rat capsules with collagenases confirmed changes in collagen. Along with current rehabilitation methods, treatment with collagenase may augment ROM recovery from knee joint contractures.
30
Pinchback, Jane Sherwood. "Investigation Of Collagenase Production And Aspects Of Vascular Pathology In Advanced Periodontitis." University of Sydney, 1995. http://hdl.handle.net/2123/5082.
Texte intégralRésumé :
Master of Science in Dentistry<br>This work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au
31
Baker, Alison Dawn. "Role of ceramide in induction of Fos, Jun, and collagenase in chondrocytes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29308.pdf.
Texte intégral
32
Beaton, Nigel Alexander. "Inhibition of collagenase by the angiotensin-converting enzyme inhibitors captopril & enalapril." Thesis, University of Strathclyde, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502348.
Texte intégralRésumé :
Collagen scaffolds provide a biocompatible matrix within tissue engineering and have already found many clinical uses. Two key requirements are that they are biologically Stable and mechanically strong. However, once seeded with cells or implanted in vivo collagen scaffolds are constantly being degraded and rebuilt. The balance of these two processes determines the matrix integrity. Studies have found that excessive degradation leads to mechanically weak matrices. The collagenases, members of the matrix metalloproteinase (MMP) family, play a vital role in matrix degradation. Collagenase inhibition should allow collagen scaffolds to retain their desirable qualities of mechanical strength and biological compatibility. Previous research has discovered that angiotensin converting enzyme (ACE) inhibitors, common hypertension drugs, inhibit MMP activity, MMP-9 specifically. The collagenases (MMP-1, MMP-8 and MMP-13) are members of the same family and are structurally similar to MMP-9 so these drugs may also inhibit collagenases.
33
Trigiante, Giuseppe. "Kinetics of collagenase in two dimensions. A new antiviral drug delivery formulation /." May be available electronically:, 1999. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Texte intégralRésumé :
Thesis (Ph. D.)--Stanford University, 1999.<br>Submitted to the Department of Chemistry. Copyright by the author. No collective title. Part 1 Kinetics of collagenase in two dimensions. Chapters "1-3". Part 2 A new antiviral drug delivery formulation. Chapters "4-8".
34
Yi, Eunice Sunyoung. "Mechanical forces accelerate collagen digestion by bacterial collagenase in lung tissue strips." Thesis, Boston University, 2012. https://hdl.handle.net/2144/12690.
Texte intégralRésumé :
Thesis (M.S.)--Boston University
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.<br>Most tissues in the body are under mechanical tension, and while enzymes mediate many cellular and extracellular processes, the effects of mechanical forces on enzyme reactions in native extracellular matrix (ECM) are not well known. Previous studies have shown that elastin remodeling in the lung occurs during the progression of emphysema, a disease that involves enzymatic cleavage of various ECM proteins of the parenchyma. Here we hypothesize that physiological levels of mechanical forces are also capable of modifying the activity of collagenase, a key remodeling enzyme of the ECM, leading to increased collagen deterioration, which results in decreased ECM stiffness. To test this, we measured the changes in mechanical properties of lung tissue strips under various conditions of stretch and digestion. Specifically, we analyzed the stiffness and nonlinearity index of tissue strips tested under uniaxial static stretch (amplitudes of 0, 20, 40, and 80% strain), as well as cyclic mechanical loading (amplitudes of ±10% and ±20% superimposed on 40% static stretch, and frequencies of 0.1 and 1Hz). We also used confocal and electron microscopy to determine and quantify changes in ECM structure. In particular, we observed qualitatively the effect of mechanical loading on enzyme activity through the increased destruction seen in our confocal and electron images. We also analyzed the changes in equivalent diameter and distortion index measurements of the alveolar structures through analysis of the confocal images. The decline in stiffness during digestion positively correlated with the increase in equivalent diameters and negatively correlated with the distortion index. These results suggest that the decline in stiffness results from collagen rupture within and of the alveolar wall, and changes in shape of the airspaces subsequent to local tissue failure.
In general, from these studies, we found that mechanical forces accelerated collagen digestion and lead to increased destruction of ECM structure of the alveoli. This research may provide new understanding of the role of collagen degradation in general tissue remodeling and disease progression.
35
Knott, Lynda. "The collagenous matrix of normal and osteoporotic avian bone." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296700.
Texte intégral
36
Rotenberg, Maurice. "L'utilisation du collagene en rehabilitation glottique et vocale." Nancy 1, 1988. http://www.theses.fr/1988NAN11261.
Texte intégral
37
Bakillah, Ahmed. "Production de collagene de type quatre et de collagenase quatre par les cellules endotheliales humaines cultivees en presence de differentes concentrations de glucose, et d'hormone de croissance : effets d'un inhibiteur de l'aldose reductase et d'un inhibiteur de proteine kinase c." Paris 5, 1994. http://www.theses.fr/1994PA05S001.
Texte intégralRésumé :
L'epaississement des membranes basales capillaires caracterise la microangiopathie diabetique. Il est associe a une accumulation de collagene de type iv qui peut etre due a une augmentation de sa biosynthese et/ou a une diminution de sa degradation. Nous avons montre dans la premiere partie de notre etude que les cellules endotheliales provenant de la veine du cordon ombilical humain, cultivees en presence de forte concentration de glucose, diminuent en nombre et augmentent leur production de collagene de type iv dose par elisa, aussi bien dans le surnageant des cultures que dans la matrice extracellulaire et les cellules. Ceci s'accompagne d'une augmentation significative de l'incorporation de #1#4c-proline dans les proteines totales et collageniques dans le surnageant de culture, dans la matrice extracellulaire et les cellules. L'etude de l'activite collagenase de type iv libre et totale apres activation par l'apma a montre une baisse significative dans le surnageant de culture. Dans une deuxieme partie nous avons etudie l'effet d'un inhibiteur de l'aldose reductase, le sorbinil, qui s'est avere capable de prevenir cette augmentation de collagene iv et de corriger la diminution du nombre de cellules observee en presence de forte concentration de glucose. Le glucose est le principal facteur, mais apparemment pas le seul, qui soit responsable de l'epaississement des membranes basales au cours du diabete. Chez les diabetiques insulinodependants ayant une bonne equilibration glycemique, il existe en effet une inegalite individuelle dans la rapidite d'apparition et la gravite des lesions de retinopathie diabetique. Cette inegalite suggere qu'un ou plusieurs facteurs aggravants, autres que l'hyperglycemie, existent chez certains diabetiques. C'est dans cette perspective que nous avons etudie dans la troisieme partie de notre travail les effets de l'hormone de croissance (hgh) susceptible d'etre l'un de ces facteurs. Nous avons etudie l'effet hgh en traitement de 72h en l'absence de serum et en presence de differentes concentrations de glucose. Hgh augmente le nombre de cellules de facon dose-dependante uniquement en presence de glucose 5,5mm : l'augmentation est de 15% a la concentration de 100ng/ml de hgh. Hgh stimule la production de collagene de type iv aussi bien dans le surnageant de culture que dans la matrice extracellulaire et les cellules aux differentes concentrations de glucose. Hgh augmente l'incorporation de #1#4c-proline dans les proteines collageniques du surnageant, de la matrice extracellulaire et des cellules, a forte concentration de glucose seulement. Nous avons observe une augmentation significative de l'activite collagenase libre apres activation par l'apma en presence de 100ng/ml de hgh et de glucose 5,5mm. Nos resultats peuvent s'expliquer en partie par l'activation d'une ou plusieurs isoformes de proteine-kinase c (pkc) par la gh et le glucose. Cette hypothese est etayee par l'utilisation, dans la derniere partie de notre etude, d'un inhibiteur des pkc (gf109203x) qui a prevenu d'une facon significative la stimulation de la production de collagene iv sous forte concentration de glucose ou de hgh. Il a ete sans effet sur l'activite de la collagenase iv. Nos resultats suggerent que le glucose et la gh peuvent favoriser l'accumulation de collagene iv dans les membranes basales, observee dans la microangiopathie diabetique, par activation d'une ou plusieurs isoformes de pkc.
38
Halaka, A. N. A. M. "Collagenolytic activities of intercranial tumours : In-vitro biochemical and immunolocalization studies." Thesis, University of Leeds, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378902.
Texte intégral
39
Wells, Paul B. "Thermal alteration of collagenous tissue subjected to biaxial isometric constraints." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2468.
Texte intégralRésumé :
Clinical thermal therapies are widespread and gaining in appeal due to
improved technology of heating devices and promising results. Outcomes of
thermal treatment are often unpredictable and suboptimal, however, due in part
to a lack of appreciation of the underlying biothermomechanics. There is a
pressing need, therefore, to understand better the role of clinically-controllable
parameters on the thermal damage processes of tissue. Heretofore,
researchers have primarily sought to understand this process through various
uniaxial experiments on tissues containing collagen as their primary constituent.
Most biological tissues experience multiaxial loading, however, with complex
boundary constraints inclusive of both isotonic and isometric conditions. The
primary focus of this work is on the isothermal denaturation of fibrillar collagen
subjected to a biaxial isometric constraint.
Results from our tests reveal a complicated process, the kinetics of which
are not easily measured. Evolving isometric contraction forces during heating
do not correlate with resultant mechanical behaviors, as thermal shrinkage does
in biaxial isotonic tests. Furthermore, resultant mechanical behaviors at variousdurations of heating reveal a two phase process with a rate dependent on the
amount of isometric stretch. For tissues heated at 75oC for 15 minutes, at which
point the first phase of mechanical alteration dominates for all constraints herein,
resultant mechanical behaviors correlate well with the amount of isometric
stretch. The correlation is similar to that between isotonic loads and resultant
mechanical behaviors from previous studies. In light of the need for a better
measure of thermal damage in isometric tests, we performed a histological
analysis of tissues heated under varying constraints. Results show a good
correlation between the level of isometric constraint and thermally-induced
histological aberrations. Finally, we demonstrate that our seemingly limited and
qualitative knowledge can be applied well to a specific clinical application:
namely, the use of glycerol as a clearing agent for laser therapies. Our results
suggest that glycerol is safe to use for such therapies because it increases the
thermal stability of fibrillar collagen, and its hyperosmotic effects on mechanical
behavior are fully reversed upon rehydration.
40
Somogyi-Ganss, Eszter. "Novel non-collagenous modulators of biomineralization in bone and dentin /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7140-101-6/.
Texte intégral
41
Walters, Valerie Irene. "Design and Analysis of a Collagenous Anterior Cruciate Ligament Replacement." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/32458.
Texte intégralRésumé :
The anterior cruciate ligament (ACL) contributes to normal knee function, but it is commonly injured and has poor healing capabilities. Of the current treatments available for ACL reconstruction, none replicate the long-term mechanical properties of the ACL. It was hypothesized that tissue-engineered scaffolds comprised of reconstituted type I collagen fibers would have the potential to yield a more suitable treatment for ACL reconstruction. Ultra-violet (UV) radiation and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) were investigated as possible crosslinking methods for the scaffolds, and EDC crosslinking was deemed more appropriate given the gains in strength and stiffness afforded to individual collagen fibers. Scaffolds were composed of 54 collagen fibers, which were made using an extrusion process, organized in accordance with a braid-twist design; the addition of a hydrogel (gelatin) to this scaffold was also investigated. The scaffolds were tested mechanically to determine ultimate tensile strength (UTS), Youngâ s modulus, and viscoelastic properties. Scaffolds were also evaluated for the cellular activity of primary rat lateral collateral ligament (LCL) and medial collateral ligament (MCL) fibroblast cells after 7, 14, and 21 days. The crosslinked scaffolds without gelatin exhibited mechanical and viscoelastic properties that were more similar to the human ACL. Cellular activity on the crosslinked scaffolds without gelatin was observed after 7 and 21 days, but no significant increase was observed with time. Although more studies are needed, these results indicate that a braid- twist scaffold (composed of collagen fibers) has the potential to serve as a scaffold for ACL replacement.<br>Master of Science
42
Brady, Jeffrey Darren. "Studies of the synthesis and metabolism of lysine derived collagen crosslinks." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386301.
Texte intégral
43
Truy, Éric. "Collagene et membrane tympanique, tissus conjonctifs et tympanoplasties : etude experimentale chez le chien de l'utilisation d'un film collagene iv humain placentaire reticule pour la myringoplastie." Lyon 1, 1988. http://www.theses.fr/1988LYO1M366.
Texte intégral
44
LE-LEPESCHEUX, LE LIEN. "Le collagene cuticulaire des annelides : organisation tridimensionnelle et autoassemblage." Paris 6, 1989. http://www.theses.fr/1989PA066692.
Texte intégralRésumé :
La cuticule des annelides est une matrice extracellulaire constituee d'un reseau fibrillaire en contreplaque quasi-orthogonal. Le constituant proteique majeur est le collagene qui se presente sous la forme de longues fibrilles helicoidales non striees, constituees de faisceaux de microfibrilles egalment helicoidaux. L'etude ultrastructurale et geometrique de la cuticule montre la presence d'un twist cholesterique cylindrique entre microfibrilles au sein de chaque fibrille. L'organisation tridimensionnelle du collagene cuticulaire est comparable a celle des molecules dans les phases bleues (etat intermediaire entre la phase isotrope et la phrase cholesterique). La cuticule des annelides est donc un analogue biologique non fluide des cristaux liquides. Le reseau cuticulaire, a symetrie cristalline, presente des defauts ou dislocations, qui sont impliques dans la croissance en diametre et en longueur de l'animal. Les cellules, par l'intermediaire des microvillosites, auraient un role ordonnateur dans le developpement et la croissance de l'animal. Toutefois, nous soulignons la pluralite des processus morphogenetiques susceptibles d'uvrer en synergie, notamment les microvillosites et leur cytosquelette, les contraintes biomecaniques et les autoassemblages de type cristallin liquide des polymeres. Le comportement cristallin liquide du collagene cuticulaire, suggere apres les observations faites in situ, se confirme in vitro grace a des experimentations dans des conditions d'autoassemblage a partir de solutions acides de molecules de collagene cuticulaire de nereis diversicolor extraites biochimiquement. En effet, les architectures fibrillaires obtenues dans les gels ainsi que la formation spontanee de phases cholesteriques a partir de solutions concentrees de molecules, montrent que le collagene cuticulaire a un comportement authentiquement cristallin liquide. Son autoassemblage serait l'un des principes phys
45
Clement, Bruno. "Modulation de la synthese de collagene par les hepatocytes." Rennes 1, 1986. http://www.theses.fr/1986REN10057.
Texte intégralRésumé :
La modulation de l'expression du collagene a ete appreciee au cours de la formation de la fibrose alcoolique chez l'homme. Tous les types de collagene peuvent etre detectes dans les hepatocytes, ce qui suggere qu'ils sont impliques dans la formation de la fibrose. Examen de la production de collagene dans les cultures primaires d'hepatocytes de rat: synthese de quantites croissantes de collagene
46
Lim, Young-tae. "Functional changes in rat achilles tendon following collagenase injury and manual soft tissue mobilization." Virtual Press, 1994. http://liblink.bsu.edu/uhtbin/catkey/917034.
Texte intégralRésumé :
The purpose of this study was to determine the functional changes due to the Graston Therapeutic Technique (GTT) in an animal model. This study attempted to verify the biomechanical changes associated with the Graston Therapeutic Technique (GTT) in order to possibly apply it to humans as a major physical therapy modality. Eighteen adult, male Sprague-Dawley rats were assigned randomly to three groups. The groups were classified as follows: (a) no injured plus GTT treatment, (b) injured minus GTT treatment, (c) injured plus GTT treatment. The GTT therapy began after one week following injury to allow for optimum inflammation and scar formation. The animals receiving GTT had six treatments over the course of two weeks. Running tests were performed on a treadmill at a velocity of 22 cm/s prior to induction of injury, one week following injury, two weeks following injury, and three weeksfollowing injury in the experimental groups. Variables analyzed were knee and ankle range of motion (ROM), stride length (SL), and stride frequency (SF). Significance of effect between experimental groups were determined by repeated measures one-way ANOVA, Scheffe's post hoc test, and Newman-Keuls post hoc test. The stride length and stride frequency results of the present study appeared to indicate that the Graston Therapeutic Technique (GTT) had an effect on changes in the stride length and stride frequency after injury. Statistical analysis between observations for the GTT plus groups indicated a significant difference in the swing phase of knee ROM. The results of this study also indicated that the Graston Therapeutic Technique may have had an influence on knee joint range of motion.<br>School of Physical Education
47
DUMAS, JACQUES. "Purification, caracterisation biochimique et immunologique de la collagenase des tissus mineralises de dent humaine." Paris 6, 1988. http://www.theses.fr/1988PA066219.
Texte intégralRésumé :
Existence d'une collogenase active dans les tissus mineralises de dent humaine, l'enzyme est purifiee a homogeneite par disomatographie. Elle est constituee d'une seule chaine peptidique, de masse moleculaire 67 kdaltoris et a point isoelectrique de 5,7. C'est une zinc-metalloproteine. Existence d'un inhibiteur endogene specifique de cette collagenase, ainsi que deux formes latentes de collagenase issues respectivement de la pulpe et des tissus mineralises, et presentant des modes d'activation differents. La production d'anticorps anticollagenase a permis de montrer l'existence de communautes immunologiques avec la collagenase pulpaire, celle de fibroblastes humains et avec une collagenase bacterienne. Une etude immunohistochimique sur des coupes dentaires montre que la presence de collagenase dans la pulpe dentaire au niveau des fibroblastes et des fibres conjonctives au niveau des odontoblastes et de leurs prolongements au front de mineralisation
48
Broutin, Isabelle. "Affinement de la structure de la collagenase d'hypoderma lineatum a 1,8 a de resolution." Paris 11, 1993. http://www.theses.fr/1993PA112318.
Texte intégralRésumé :
Les collagenases, seuls enzymes degradant le collagene dans les conditions physiologiques de ph et de temperature, jouent un role essentiel pour l'equilibre dynamique du collagene dans le tissu conjonctif. Elles appartiennent a deux familles, les metallo-proteases et les proteases a serine. La collagenase que nous avons etudiee appartient a cette derniere. Elle est extraite des parasites du betail hypoderma lineatum, responsables de l'hypodermose qui affecte certains mammiferes et provoque une baisse des rendements zootechniques. La collagenase d'hypoderma lineatum a un poids moleculaire de 25200 daltons pour 230 acides amines. Elle cristallise dans le groupe d'espace i422, en presence de sulfate d'ammonium a ph neutre, en absence d'inhibiteur. Les parametres de maille sont a=111,7 a et c=165,8 a avec deux molecules par unite asymetrique. Elle est inhibee par le dipf mais aucun inhibiteur peptidique n'est connu a ce jour. Au debut de cette these ont ete commercialises des detecteurs bidimensionnels. Nous avons utilise la collagenase comme outil de calibration pour tester le fast (enraf nonius), le xentronics (siemens), et enfin, lorsqu'il fut disponible, le prototype mark ii (detecteur realise a lure par r. Kahn et col. En collaboration avec le groupe de g. Charpak au cern). Nous avons effectue une etude comparative qui montre que la qualite des jeux de donnees obtenus a l'aide de detecteurs commerciaux et de sources conventionnelles s'est nettement amelioree durant ces dernieres annees tout comme les programmes de traitement du signal. Pour obtenir des donnees a haute resolution, l'utilisation conjointe du rayonnement synchrotron et du detecteur prototype mark ii reste la reference. La resolution de la structure de la collagenase a ete initiee lors de la these de doctorat de b. Arnoux (1985) mais n'avait pu etre menee a bien. La position des deux molecules de l'unite asymetrique avait ete determinee a 3 a de resolution, mais la structure necessitait une reconstruction importante au niveau des boucles. Nous avons du utiliser des methodes nouvelles et classiques pour amorcer la convergence de l'affinement. Plusieurs reconstructions manuelles sur ecran graphique furent ensuite necessaires avant de pouvoir reinterpreter la carte de densite electronique. Le facteur d'accord r final est de 18,3% sur la totalite des reflexions a 1,8 a de resolution et 295 molecules d'eau ont ete placees dans la densite electronique. Les nombreuses difficultes pour resoudre cette structure ont ete interpretees a posteriori par la mauvaise qualite des phases mir (76) et un modele de depart errone (rms=3 a) qui ont bloque pendant longtemps le processus d'affinement. La courbe de luzzati montre que l'erreur sur les positions atomiques de la structure finale est comprise entre 0,15 et 0,25 a. La collagenase d'hypoderma lineatum est constituee de deux domaines de feuillets anti-paralleles replies en tonneau. Elle possede trois ponts disulfure qui stabilisent la structure. Les deux molecules de l'unite asymetrique sont reliees entre elles par un pseudo axe de symetrie non cristallographique d'ordre 2. L'ecart moyen sur la chaine principale est de 0,27 a. La collagenase presente la meme structure secondaire que les autres proteases a serine. Elle coupe des substrats de la thrombine et de la kallikreine, bien que l'encombrement de sa poche specifique soit similaire a celle de l'elastase (val-216, val-226, ser-189). La collagenase ayant ete clonee recemment, rendant possible une etude structure/fonction pour determiner sa specificite vis-a-vis du collagene
49
Nguyen, Elise B. "Electrical Stimulation of Human Dermal Fibroblasts and the Quantification of Collagen, Collagenase, and Elastin." Thesis, California State University, Long Beach, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10263522.
Texte intégralRésumé :
<p> Electrical stimulation of tissues has been found to have many uses in pain management, antibacterial treatment, and wound healing. <i> In vivo,</i> it is known to stimulate epidermal migration and increase fibroblast cell proliferation. Here the effects of electrical field (EF) stimulation on collagen, elastin, and collagenase expression in human dermal fibroblasts are studied. The cells are stimulated in bioreactor using square wave voltage pulses controlled by potentiostat for up to 24 h period. The pulse voltage (0–10V), pulse bias (0, +,−), pulse time (10–1000 ms), rest time (0.1–10 s) was varied. The effects of EF stimulation is evaluated in terms of protein expression level and changes in cell morphology. The results show that the expressions of these proteins are correlated and are doubled when EF stimulation larger than 3V and positive bias is applied. The shorter pulse time stimulates the cells more effectively, while the rest time between pulses has smaller effect.</p>
50
Messent, Anthea Jane. "Novel roles for matix metalloproteinases in cell-matrix interactions." Thesis, Open University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242514.
Texte intégral