Dissertations / Theses on the topic 'Scar healing'

Introduction Cutaneous scars represent a common surgical complication, yet no effective drug therapy for scar treatment currently exists despite huge patient and physician demand. A connexin 43 (Cx43) carboxyl terminus (CT) mimetic peptide, alpha Connexin Carboxy-Terminus 1 (αCT1), has demonstrated efficacy in improving long-term scar appearance in pre-clinical and clinical trials. However, current understanding of the mechanism-of-action by which αCT1 improves long-term scar appearance with early intervention treatment is not well understood. Methods In vivo: Scar biopsies from 1) human, 2) Sprague-Dawley rat, and 3) IAF Hairless guinea pig trials of αCT1 were examined for collagen matrix structure at 4 weeks (all models), and 2 and 6 weeks (rat and guinea pig models only). Collagen matrix variables examined included local disorganization of the fibers, a variable that is higher in unwounded skin compared to scar tissue, and density of the fibers, which is higher in scar tissue but can also be used as an early temporal marker of the rate of healing. In vitro: Primary murine dermal fibroblasts were isolated from the whole dermis of 3-4 week old transgenic mice expressing collagen 1(α2) GFP-tpz. Cells were sorted for expression via FACS and plated on prealigned collagen substrate for 7 days under conditions favorable to generating extracellular matrix. Results All in vivo scar biopsies demonstrated some level of altered collagen matrix structure with αCT1 treatment. Treated scars had higher local disorganization of the collagen fibers within the wound, and an increase in collagen matrix density compared to control at certain earlier timepoints that tended to decrease or disappear at later timepoints. The IAF Hairless guinea pig, a novel splinted wound healing model presented herein, was found to closely replicate the human dermal collagen profile and changes in collagen profile spurred by αCT1, significantly outperforming the traditional rat model. Primary dermal murine fibroblasts treated in vitro with αCT1 significantly increased synthesis of procollagen 1, the precursor of collagen 1 necessary for constructing the extracellular matrix, suggesting that at least part of the reason for higher collagen density at early in vivo timepoints is due to increased collagen synthesis by fibroblasts. Conclusion αCT1 treatment in the early stages of wound healing prompts individual fibroblasts to increase their output of collagen and create a more disorganized early collagen matrix. These early changes potentially spur the long-term scar appearance improvements seen in clinical trials, and provide a basis for future work to discover the cellular pathways to alter in order to improve wound healing and cutaneous scarring outcomes.
Doctor of Philosophy
Skin wounds frequently result in scars that can range from barely visible to enormous eyesores. Almost everyone will experience at least one skin wound in their lifetime leading to a scar that they wish were less visible, feeding the multi-billion dollar market for anti-scarring agents. However, many of the products on store shelves that claim to reduce scar appearance have not proven those claims. Most of the therapies that do have some degree of scientific evidence to support their claims are difficult to use properly, such as silicone sheeting, and often result in only minor improvements to scar appearance. Alpha Connexin Carboxy-Terminus 1 (αCT1), marketed in clinical trials as Granexin® gel, is a protein-based therapy that works on the cellular level to fundamentally alter the skin's initial reaction to wounding and improving long-term scar appearance. This dissertation explores the link between cellular processes altered by αCT1 and long-term clinical improvements in scar appearance by studying both the extracellular matrix present in the scar in human and animal models and the creation of that extracellular matrix by dermal fibroblasts. In both human and animal models, topical application of αCT1 had no effect on skin surface appearance at early timepoints of 2-6 weeks, correlating with previous research that found scar appearance only improved at 3+ months post-injury. However, deep within the newly constructed tissue of the scar, these studies show the collagen organizational structure of αCT1-treated scars is more similar to unwounded skin and slightly more dense at early timepoints, suggesting αCT1 marginally improved the speed of healing. These findings in humans and animals were also verified in part in cell culture experiments that found dermal fibroblasts increased collagen output in response to αCT1 treatment. A novel wound healing model in the hairless guinea pig, superior at replicating human skin than established models like the rat, is also presented and shown to have effects strongly similar to the human with αCT1 treatment. These results provide a fundamental insight into the mode-of-action by which αCT1 may improve long term scar appearance and identifies early collagen structure as a target for future therapeutics to modify, as well as a new animal model in which to test them.

Using in vitro models that mimic various aspects/stages of wound healing, this thesis attempted to define the events that lead to the culmination of the fibro-proliferative phase of wound healing, i.e. apoptosis and any potential defects exhibited by keloid scars. Normal scar-derived fibroblasts were found to undergo apoptosis in contractile collagen gels, whereas keloid fibroblasts did not. Investigation of the mechanisms involved indicated that this form of apoptosis required both the three-dimensional and collagenous nature of the gel and was not simply caused by removal of tension, but required biochemical cues. Collagen-contraction-induced apoptosis was found to require matrix metalloproteinase (MMP) and autocrine transforming growth factor-P (TGF-p) activity. Indeed contraction was accompanied by significantly increased expression and activation of MMPs along with indications of increased matrix breakdown. Furthermore, pure products of matrix breakdown significantly induced apoptosis of normal scar cell monolayers. The defect exhibited by keloid fibroblasts was found to be specific to that induced during collagen contraction since they were equivalent to normal scar cells in their sensitivity to other forms of apoptosis induction and demonstrated normotrophic p53 stabilisation and activation of PARP (Poly(ADP-ribose)polymerase) and caspase-3. During collagen contraction, keloid fibroblasts failed to produce biochemical cues of apoptosis and although they exhibited normal levels of MMP gene expression and activation, they failed to breakdown collagen gels. However, these cells did undergo apoptosis in response to the biochemical cues produced on normal scar cell contraction of collagen gels, but surprisingly could not respond to pure forms of matrix breakdown products. Unlike normal scar cells, keloid fibroblasts failed to differentiate into myofibroblasts in collagen gels. The addition of exogenous TGF-pl was found to restore differentiation and furthermore allowed the cells to undergo apoptosis in collagen gels. Surprisingly, TGF-pl also restored the ability of keloid cells to undergo apoptosis in response to matrix breakdown products.

Final publication is available at http://onlinelibrary.wiley.com/doi/10.1002/term.2060/abstract;jsessionid=F0849D98381EEF9E83401A02B9042F4D.f04t02
Kyoto University (京都大学)
0048
新制・課程博士
博士(医学)
甲第19602号
医博第4109号
新制||医||1014(附属図書館)
32638
京都大学大学院医学研究科医学専攻
(主査)教授 別所 和久, 教授 伊佐 正, 教授 川口 義弥
学位規則第4条第1項該当

Die Narbenbildung des Hautorgans stellt für die gegenwärtige Medizin weiterhin eine schwierige Aufgabe dar. Die frühzeitige Beeinflussung des Wundheilungspro- zesses hin zu einer verminderten oder narbenlosen Heilung scheint von entschei- dender Bedeutung. Ein vielversprechender Ansatz ist die präoperative Laserthe- rapie und dadurch erzeugte Hitzeschockantwort. Auf molekulare Ebene kommt es u.a. zur Expression von Hitzeschockproteine. Die vorliegende in-vitro Studie beschäftigte sich mit der laserinduzierten Hochregulation des Hitzeschockproteins 70 in den epidermalen Schichten. Hierfür wurden drei nicht ablative Lasersysteme mit insgesamt 12 verschiedenen Parametereinstellungen verwendet (1.540-nm Er:Glass- , 755-nm Alexandrit-, 1.064-nm Nd:YAG-Laser). Mithilfe eines humanen Hautexplantatmodells sollte unter gleichbleibenden Bedingungen Zeitpunkt und Konzentration der maximal induzierten Hsp70-Expression sowie epidermale Schä- digungen dargestellt werden. In der verfügbaren Literatur waren hierzu nur begrenzt Daten vorhanden. Alle drei Lasersysteme zeigten signifikante Hsp70-Expressionen. Der Zeitpunkt der maximalen Hsp70-Expression konnte zwischen Tag 1 und 3 festgehalten werden. Dabei zeigten die Lasersysteme unterschiedliche Hsp70- Maxima und unterschiedliche Epidermisschädigungen. Die Ergebnisse ließen schlussfolgern, dass eine potenzielle präoperative Narbenprävention tendeziell ein Tag vor dem chirurgischen Eingriff und mit den stärkeren Parametereinstellungen des 1.064-nm Nd:YAG Lasers durchgeführt werden sollte.

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The skin is a coating tissue which undergoes permanent environmental action, often in aggressive forms, causing damage to this tissue. Generally, in the repair process structural changes occur which progress to the development of a scar. In this case the tissue may present morphological changes that interfere with its mechanical properties and this repair process produces a tissue with different properties than of the original tissue. Therefore, the use of therapies that favor this repair is important to seek a better scar quality. Low-level laser therapy appears as a resource used in the modulation of the inflammatory process helping the skin repair process. The objective of this study was evaluate the effect of low level laser (830nm) with 100 mW of potency us ing 1J or 3J of energy comparing to the effect of the topical sodium diclofenac on the repair process of the rat´s skin after induction of injury, analyzing the biomechanical behavior and histological changes of skin, 28 days after the harmful process. Male Wistar rats between 150g to 200g, 3 months old were used. The animals were anesthetized with association of xylazine hydrochloride and ketamine (90mg / kg and 10mg / kg, respectively, intraperitoneal injection). Once anesthetizd, 2 lesions were performed using a surgical scalpel at the dorsal area of the animal. The animals were divided into 5 groups of 7 animals: control (CTL), untreated scar (NT), scar + anti-inflammatory (DIC), scar + 1J laser (L1J) and scar + 3J laser (L3J). The pharmacological treatment and laser therapy were performed immediately after lesion induction and maintained daily irradiation until day 7. After 28 days, the animals were euthanized with an overdose of the same anesthetic and the tissue was immediately removed for histological analysis and traction trials. Results: Both the NT and group DIC showed a reduction of mechanical properties and alterations in histology analysis. L1J group showed significant improvement in mechanical properties and histological organization. We conclude that laser therapy improves certain mechanical properties of skin in this lesion model. However, more studies should be conducted to understand the proportion and organization of collagen fibers I and III biochemicaly. Either the study can be longer and evaluate the scars after the remodeling process.
A pele é um tecido de revestimento que sofre permanente ação do ambiente, muitas vezes de forma agressiva, levando a lesão deste tecido. Geralmente em seu processo de reparo ocorrem alterações estruturais que evoluem para o desenvolvimento de uma cicatriz. Neste caso o tecido pode apresentar alterações morfológicas que interferem em suas propriedades mecânicas e este processo de reparo produz um tecido com propriedades diferentes do tecido original. Dessa forma, a utilização de terapias que favoreçam esta reparação é importante para buscar uma qualidade melhor da cicatriz. A terapia com laser de baixa potência aparece como um recurso utilizado na modulação do processo inflamatório auxiliando no processo de reparo da pele. O Objetivo deste trabalho foi avaliar o efeito da terapia com laser de baixa potência de 830nm, com 100mW de potência nas energias de um 1J e 3J comparativamente ao efeito do diclofenaco de sódio tópico no processo de reparo da pele de ratos, após a indução de uma lesão controlada, observando aspectos histológicos e biomecânicos. Foram utilizados ratos wistar, entre 150g à 200g, com 3 meses de idade. Os animais foram anestesiados com associação de cloridrato de quetamina e xilazina (90mg/Kg e 10mg/Kg respectivamente, injeção intraperitoneal). Depois de anestesiados, foram realizadas 2 lesões cortantes utilizando um bisturi cirúrgico, no dorso do animal. Os animais foram divididos em 5 grupos de 5 animais: Controle (CTL), Cicatriz sem tratamento (NT), Cicatriz + Diclofenaco de sódio tópico (DIC), cicatriz + laser 1J (L1J) e cicatriz + laser 3J (L3J). O tratamento farmacológico e a terapia laser foram realizados imediatamente após a indução da lesão e mantida a irradiação diária até o sétimo dia. Após 28 dias, os animais foram eutanasiados com hiperdosagem do mesmo anestésico e o tecido foi imediatamente retirado para análises histológicas e de ensaios de tração. Resultados: Tanto o grupo NT quanto o grupo DIC apresentaram redução das propriedades mecânicas e alterações nas análises histológicas. O grupo tratado L1J e o grupo L3J apresentaram significativa melhora das propriedades mecânicas e na organização histológica. O grupo L1J apresentou resultados histológicos e biomecânicos próximos ao tecido saudável do grupo CTL. Conclusão: Concluímos que a utilização do diclofenaco de sódio tópico não conseguiu melhorar as características histológicas e biomecânicas da pele após a indução da lesão. A terapia com laser de baixa potência foi eficaz na melhora destas propriedades, sugerindo um melhor reparo tecidual. Porém, mais estudos devem ser realizados visando entender a proporção e organização das fibras de colágeno ou mesmo o estudo de tempos de reparo superiores ao utilizados neste estudo.

Orientador: Aristides Augusto Palhares Neto
Resumo: Introdução: A cicatriz desempenha um importante papel no resultado final de uma cirurgia. Muitos fatores são implicados no processo de cicatrização patológica, e diversos produtos e curativos foram desenvolvidos para prevenção de cicatriz hipertrófica e quelóide, porém poucos tem evidências que o suportem. Objetivos: Comparar o resultado da cicatriz cirúrgica após utilização da fita de silicone e da fita microporosa. Métodos: Realizamos um ensaio clínico controlado, cego e randomizado, onde um lado da incisão foi randomizado para receber a fita de silicone e o outro lado recebeu o tratamento controle (fita adesiva microporosa). Foram selecionadas pacientes submetidas a abdominoplastia ou mastoplastia de aumento com implantes de silicone no período de maio a outubro de 2016. A Escala de Cicatrização de Vancouver foi utilizada para avaliar as cicatrizes. Resultados: Foram selecionadas para o estudo 17 pacientes. A idade média das pacientes foi de 31,4 ± 6,7, sendo a mínima de 20 e a máxima de 45 anos. Vemos na comparação dos tipos de curativo que os valores de p foram próximos a 5%, sugerindo uma associação do uso da fita de silicone com melhores resultados estéticos e funcionais da cicatriz em relação à fita microporosa. Notamos também que os dois tipos de curativo tiveram uma redução significativa em seus escores do primeiro para o terceiro mês (traduzindo uma melhora no aspecto da cicatriz), porém a fita de silicone teve uma redução superior à fita microporosa (45,6% e 39,2%... (Resumo completo, clicar acesso eletrônico abaixo)
Mestre

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Introdução: A cicatriz desempenha um importante papel no resultado final de uma cirurgia. Muitos fatores são implicados no processo de cicatrização patológica, e diversos produtos e curativos foram desenvolvidos para prevenção de cicatriz hipertrófica e quelóide, porém poucos tem evidências que o suportem. Objetivos: Comparar o resultado da cicatriz cirúrgica após utilização da fita de silicone e da fita microporosa. Métodos: Realizamos um ensaio clínico controlado, cego e randomizado, onde um lado da incisão foi randomizado para receber a fita de silicone e o outro lado recebeu o tratamento controle (fita adesiva microporosa). Foram selecionadas pacientes submetidas a abdominoplastia ou mastoplastia de aumento com implantes de silicone no período de maio a outubro de 2016. A Escala de Cicatrização de Vancouver foi utilizada para avaliar as cicatrizes. Resultados: Foram selecionadas para o estudo 17 pacientes. A idade média das pacientes foi de 31,4 ± 6,7, sendo a mínima de 20 e a máxima de 45 anos. Vemos na comparação dos tipos de curativo que os valores de p foram próximos a 5%, sugerindo uma associação do uso da fita de silicone com melhores resultados estéticos e funcionais da cicatriz em relação à fita microporosa. Notamos também que os dois tipos de curativo tiveram uma redução significativa em seus escores do primeiro para o terceiro mês (traduzindo uma melhora no aspecto da cicatriz), porém a fita de silicone teve uma redução superior à fita microporosa (45,6% e 39,2% respectivamente). Conclusão: A fita de silicone parece ser discretamente mais efetiva em promover melhoria da cicatriz cirúrgica a médio prazo, com base na Escala de Cicatrização de Vancouver, em relação à fita microporosa. Ambas as fitas apresentaram melhora no escore do terceiro mês de pós-operatório quando comparados ao primeiro mês, porém a fita de silicone apresentou uma redução superior. Os pontos de maior diferença constaram na pliabilidade, altura e vascularização. Quanto aos efeitos adversos, ambos os curativos apresentaram como intercorrência o surgimento de rash cutâneo, sendo que o surgimento foi maior com o uso da fita de silicone (RR=2).
Introduction: The scar plays an important role on result of any surgery. Many factors are implied in the pathologic scar healing process. Lots of dressings and products have been developed to prevent formation of hypertrophic scar and keloids, but few have been supported by evidence. Objective: To compare the surgical scar result after using silicone-gel sheeting and microporous tape. Methods: We’ve performed a blind and randomized clinical trial, using the silicone-gel sheeting on one side of the surgical incision and the control-treatment on the opposite site (microporous tape). Selected patients underwent abdominoplasty or augmentation mastoplasty with silicone implants from May to October of 2016. The Vancouver Scar Scale (VSS) was assessed to evaluate the scars. Results: Seventeen patients were selected for the study. The mean age was 31,4 ± 6,7, with the youngest at 20 and the oldest with 45 years-old. Comparing the two dressing types, we found that p values were close to 5%, suggesting that the siliconegel sheeting promotes better aesthetic and functional results over the microporous tape. We also noticed that both dressings had a significant reduction on the VSS score from the first to the third month of post-operative, although the silicone-gel sheeting had a superior reduction (45,6% and 39,2%). Conclusion: Silicone-gel sheeting appears to be slightly more effective in promoting mid-term improvement of surgical scar, related to the VSS, and compared to microporous tape. Both dressings provided an upgrade on VSS score from the first to the third post-operative month evaluation, but the silicone-gel sheeting was superior. Most of the difference relied on pliability, height and vascularization. As to the side effects, both dressings presented with skin rash, but the silicone-gel sheeting had a higher occurrence (RR=2).

Stable single-unit recordings from the nervous system using microelectrode arrays can have significant implications for the treatment of a wide variety of sensory and movement disorders. However, the long-term performance of the implanted neural electrodes is compromised by the formation of glial scar around these devices, which is a typical consequence of the inflammatory tissue reaction to implantation-induced injury in the CNS. The glial scar is inhibitory to neurons and forms a barrier between the electrode and neurons in the surrounding brain tissue. Therefore, to maintain long-term recording stability, reactive gliosis and other inflammatory processes around the electrode need to be minimized. This work has succeeded in the development of neural electrode coatings that are capable of sustained release of anti-inflammatory agents while not adversely affecting the electrical performance of the electrodes. The effects of coating methods, initial drug loadings on release kinetics were investigated to optimize the coatings. The physical properties of the coatings and the bioactivity of released anti-inflammatory agents were characterized. The effect of the coatings on the electrical property of the electrodes was tested. Two candidate anti-inflammatory agents were screened by evaluating their anti-inflammatory potency in vitro. Finally, neural electrodes coated with the anti-inflammatory coatings were implanted into rat brains to assess the anti-inflammatory potential of the coatings in vivo. This work represents a promising approach to attenuate astroglial scar around the implanted silicon neural electrodes, and may provide a promising strategy to improve the long-term recording stability of silicon neural electrodes.

The skin acts as a protective barrier, is crucial for thermoregulation and also forms part of the sensory, immunological and endocrine system. Therefore skin preservation is paramount to preserving life. The loss of skin homeostasis, through injury, initiates the wound healing process where the final outcome is the formation of a scar. Scar treatment remains a challenge, despite a plethora of treatments, resulting in a poor outcome and sub-optimal response to existing therapies. Photodynamic therapy (PDT) has been used to treat oncologic conditions affecting the skin. Its action depends on a photosensitiser and a specific light source. Aminolevolinic acid (5ALA) and its methyl ester (MALA) are commonly used pro-drugs of the photosensitiser protoporphyrin IX (PpIX), which in combination with red light produces reactive oxygen species (ROS). ROS will cause different responses such as cell death and tissue destruction. There is limited clinical evidence emerging for the use of PDT in treating wound healing and pathological skin scarring. For this reason, further investigations are required to better understand the role of PDT in adult human skin wound healing and skin scarring. The aim of this investigation was to evaluate the accumulation of PpIX after exposure to 5ALA or MALA, phototoxicity of red light arrengment, citotoxicity, cell death inducction, ROS generation and a gene related analysis post-PDT in keloid fibroblasts compared to normal skin fibroblasts. Optimization of a wound healing organ culture (WHOC) model and evaluation of re-epithelialization, cell death, proliferation, extracellular matrix arreangment (ECM) and a related gene analysis after 5ALA-PDT ex vivo. General histology, cell death, proliferation, ECM rearrengment and a gene related analysis after PDT in skin scarring ex vivo. This investigation found PpIX accumulation higher with MALA compared to 5ALA. Phototoxicity and cytotoxicity was site specific within the lesion and increased proportionately to fluence rates. ROS generation leads to the decrease of cytoproliferation and increased apoptosis and necrotic cell death, COLI, COLIII an HSP70 were found down-regualted. Ex vivo wound geometry, system of support and growth media were optimized in a human wound healing organ culture (WHOC). WHOCs treated with 5ALA-PDT (20 J/cm2), showed an advancing re-epithelialization tongue 3.5 folds longer, which were highly proliferative, showing increased CK14 and p16 levels. The neo-epidermis was fully differentiated and neo-collagen was present. PCNA, p16, COLI, COLIII, MMP3, MMP19 and alpha-SMA were significantly more expressed in the dermis. MALA/5ALA-PDT (40 J/cm2) applied to striae alba, fine line, hypertrophic and keloid scars ex vivo coused an increased of apoptosis while proliferation decreased, matrix components were found to be re-organised, both according to the severity of the scar. COLI and COLIII genetic expression decreased while MMP3 and tropoelastin increased significantly. However, no statistically significant difference was observed between 5ALA and MALA-PDT treatments. In conclusion, this thesis shows that cytotoxicity post-PDT in KD fibroblasts is dependent on the lesional site within the scar, a precursor of intracellular photosensitiser and fluence. PDT in wound healing ex vivo shows increased re-epithelialization and ECM reconstruction and remodelling. Finally, in dermal fibrosis morphological and cellular effects of the application of PDT correlate with the degree and severity of dermal fibrosis. In view of this, PDT may be ideal for treating abnormal skin scarring and improving human cutaneous wound healing.

Il s’agit, dans ce travail, de trouver le geste qui renouvelle l’identité cicatrisée que le «guerrier » en nous recherche, à travers la pratique martiale définie comme habitation holiste d’un corps-soit, ce que Varela appelle « l’inscription corporelle de l’esprit ».Un être, par l’effet d’un art et par la compréhension de « l’expérience de l’expérience » que constitue la performativité du geste en général, peut-il jamais faire Un avec les choses qui l’entourent et qui l’enveloppent ? Il y a à parier que s’il y arrivait, il lui serait donné de saisir à la fois le caractère mythique des choses en tant qu’il est immanent à leur présence et cette présence en tant qu’oeuvre existentielle. L’art martial ninja constitue une telle réussite. Cette thèse en interroge les effets …
This work consists in finding the gesture that renovates the healed identity, a “worrior” withinus is looking for, through a martial practice defined as a holistic dwelling of a body-being.This is what Varela calls “the corporeal inscription of the spirit”.Is a being able to make one with the things surrounding and covering it, through the effect ofart and the comprehension of “the experience of the experience”, that the performativity of thegesture generally constitutes? It would bet, if possible, that it would be able of creating, at thesame time, the mythic aspect of things, having been inherent to their presence, and creatingthis presence as an existential art-workNinja martial art builds such a success, the effects of which are questioned by this thesis

Scar-free wound healing and regeneration are uncommon phenomena permitting the near complete restoration of damaged tissues, organs and structures. Although rare in mammals, many lizards are able to undergo scarless healing and regeneration following loss of the tail. This study investigated the spontaneous and intrinsic capacity of the leopard gecko (Eublepharis macularius) tail to undergo scar-free wound healing and regeneration following two different forms of tail loss: autotomy, a voluntary and evolved mechanism of tail shedding at fracture planes; and surgical amputation, involuntary loss of the tail outside the fracture planes. Furthermore, I investigated the ability of the regenerate tail to regenerate by amputating a regenerate tail (previously lost by autotomy). To investigate these phenomena I imaged wound healing and regenereating tails daily (following autotomy and amputation) to document gross morphological changes. I used histochemistry to document tissue structure and immunohistochemistry to determine the tissue/cellular location of my five proteins of interest (PCNA, MMP-9, WE6, α-sma, TGF-β3). Each of these proteins of interest has been previously documented during wound healing and/or regeneration in other wound healing/regeneration model organisms (e.g. mice, urodeles, lizards, zebrafish). Scar-free wound healing and regeneration occurred following autotomy, amputation of the original tail and amputation of the regenerate tail, indicating that the leopard gecko tail has an instrinsic scar-free wound healing and regenerative capacity that is independent of the mode of tail loss (autotomy or amputation). Furthermore immunohistochemistry revealed a conserved sequence and location of the expression of the five proteins of interest following both forms of tail loss. These results provide the basis for further studies investigating scar-free wound healing and regeneration in a novel amniote model, the leopard gecko.
NSERC

碩士
靜宜大學
台灣文學系
100
Seba is a writer who is very popular on internet. A lot of readers give their responses to the topics on her blog. The special literary phenomenon has not been discussed. Characters in the novel grow up through different trips, this is the most special narrative of her novels. Readers get some ideas through characters treat themselves. So, the readers consider that there are curative functions in her novels. 　　We also analyze the readers how to get the "healing" though the narrative modes and reader’s effects on her blog. The results show that readers get seven emotional effects to the reading process "praise", "identification", "appeasement", "catharsis", "unique outcome", "insight" and "reflection". Readers express negative emotion and establish the meaning of their lives after reading the novels. We will use the responses of readers and the narrative pattern of her novels, proving that there are healing effects in her novels, and also approving that the novels can give the readers some positive emotions. 　　We study the special phenomenon between the internet novels and readers, and also study how to make the reader feel the healing. We show the "scars" and "comprehension" of her novel from four parts of study. The first, we observe that the reader effects; secondly, we study the narrative modes; thirdly, we analyze the reader effects; fourthly, we have observed how these novels affect reader’s emotions. Basing on the above, we define the new value of internet novel.

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Following traumatic injury, skin has the capacity to repair itself through a complex cascade of biochemical change. The dermis, which contains a load-bearing collagenous network structure, is remodelled over a long period of time, affecting its mechanical behaviour. This study examines the nanomechanical and viscoelastic properties of the upper dermis from human skin that includes both healthy intact and scarred tissue. Extensive nanoindentation analysis shows that the dermal scar tissue exhibits stiffer behaviour than the healthy intact skin. The scar skin also shows weaker viscoelastic creep and capability to dissipate energy at physiologically relevant frequencies than the adjacent intact skin. These results are discussed in conjunction with a visual change in the orientation of collagenous fibrils in the scarred dermis compared with normal dermis, as shown by atomic force microscopy imaging.

The transforming growth factor beta (TGFβ)/activin signaling pathway has a number of documented roles during wound healing and is becoming increasingly appreciated as a vital component of multi-tissue regeneration. The leopard gecko (Eublepharis macularius) is able to spontaneously, and repeatedly, regenerate its tail following tail loss. We thus examined the expression and localization of several key components of the TGFβ/activin signaling pathway during tail regeneration of the leopard gecko. We observed a marked increase in phosphorylated-Smad2 expression among regenerating tissues corresponding to the location of the regenerate blastema. Interestingly, we observe that during early regeneration there appears to be an absence of TGFβ family member TGFβ1 and instead a strong upregulation of activin-βA. We also observe the expression of EMT transcription factors Snail1 and Snail2 in blastemal tissue. These observations combined with other data provide strong support for the importance of unique and non-overlapping expression patterns of different TGFβ ligands during multi-tissue regeneration

abstract: Traumatic injury to the central nervous or musculoskeletal system in traditional amniote models, such as mouse and chicken, is permanent with long-term physiological and functional effects. However, among amniotes, the ability to regrow complex, multi-tissue structures is unique to non-avian reptiles. Structural regeneration is extensively studied in lizards, with most species able to regrow a functional tail. The lizard regenerated tail includes the spinal cord, cartilage, de novo muscle, vasculature, and skin, and unlike mammals, these tissues can be replaced in lizards as adults. These studies focus on the events that occur before and after the tail regrowth phase, identifying conserved mechanisms that enable functional tail regeneration in the green anole lizard, Anolis carolinensis. An examination of coordinated interactions between peripheral nerves, Schwann cells, and skeletal muscle reveal that reformation of the lizard neuromuscular system is dependent upon developmental programs as well as those unique to the adult during late stages of regeneration. On the other hand, transcriptomic analysis of the early injury response identified many immunoregulatory genes that may be essential for inhibiting fibrosis and initiating regenerative programs. Lastly, an anatomical and histological study of regrown alligator tails reveal that regenerative capacity varies between different reptile groups, providing comparative opportunities within amniotes and across vertebrates. In order to identify mechanisms that limit regeneration, these cross-species analyses will be critical. Taken together, these studies serve as a foundation for future experimental work that will reveal the interplay between reparative and regenerative mechanisms in adult amniotes with translational implications for medical therapies.
Dissertation/Thesis
Differentially Expressed Genes in the Early Regenerating Lizard Tail
Gene Ontology of Differentially Expressed Genes in the Early Regenerating Lizard Tail
KEGG and Reactome Pathway Analysis of Differentially Expressed Genes in the Early Regenerating Lizard Tail
3D Reconstruction of an Alligator Regenerated Endoskeleton
Lateral 2D Serial Sections of a Regenerated Alligator Tail
Doctoral Dissertation Biology 2020

Introduction Keloids are formed by the excessive production of scar tissue, which extends beyond the margins of the original injury, often resulting in lesions of grotesque dimensions. Keloids present a major dilemma to surgeons because of the high recurrence rate with recurrent growth often larger than the original keloid. The high recurrence rate and the poor response of keloids to therapy present a great challenge to surgeons. The numerous therapeutic regimens demonstrate that to date there is no single therapy that is absolutely successful. Therefore, it is necessary to comprehensively establish the pathology of keloids and to determine the aetiopathogenesis of the lesion in order to eventually provide unfailing specific effective treatment and to better understand the mechanisms regulating fibrosis in various fibroproliferative diseases. Aim To evaluate the pathology and aetiopathogenesis of keloid formation. Methods The research protocol for the study was approved by the Nelson R Mandela Faculty of Medicine Ethics Committee. Informed consent was obtained before the biopsies were taken. Keloid and non-lesional skin biopsies were obtained from thirty two patients who had multiple lesions in various locations, bringing the total number of keloids and apparently normal skin biopsies processed and examined to fifty eight. The biopsied specimens were processed for paraffin wax embedment and routine haematoxylin and eosin, differential and immunocytochemical staining. Sections were scrupulously examined using the Olympus BH-2 microscope; features pertinent to the study were photographed with the Olympus DP 10 microscope digital camera system. The stored images were studied, using the Camedia graphics processing programme. Results The results of the study showed that keloids comprise many distinct regions categorized as: the zone of hyalinising collagen bundles, fine fibrous areas, areas of inflammation, zone of dense regular connective tissue, nodular fibrous area and area of angiogenesis. Fibroblastic phenotypes present ranged from spindle, fibrohistiocytic, epitheloid, elongated flattened condensed fibroblastic cells to few wavy, fuzzy, polygonal and atrophic cell types. Immunocytochemically these cells were vimentin-positive and actin- and desmin-negative. Few myofibroblastic phenotypes were also identified and these were vimentin- and alpha smooth muscle actin-positive and desmin-negative. The fibroblastic and myofibroblastic phenotypes were in proliferative or degenerative stages and pathological features exhibited were the presence of vesicular, degenerate or calcified nuclei; nuclear and plasma membrane damage; cytoplasmic and nucleoplasmic clearing; atrophy, pyknosis and swelling. Severe, moderate to mild paravascular inflammation was observed around the microvessels of the sub-papillary plexus and within the keloid. There was compression and occlusion of small blood vessels, coagulation necrosis and dissolution of mural cells of small blood vessels and small peripheral nerves. Also present in keloids were oedematous areas, disorganised and hyalinised connective tissue fibres and increased numbers of degranulated and degranulating mast cells. Elastic fibres in keloids were minimal or absent whereas at the border of keloids there was an increase.Discussion Degenerate, occluded and compressed microvessels were a widespread pathological feature in keloids. This resulted in impaired vascular supply to each of the keloid regions which impacted directly on the pathology of keloids where degeneration and necrosis, manifesting the lack of nutrients and oxygen to tissue, were found throughout the keloid. The vascular supply was impaired because of the chronic inflammatory destruction of the microvessels and the elevated stress within keloids. Factors contributing to increased intrinsic stress were: 1) the lack of elastic fibres in keloids which decreased the elastic limit, leading to effects of excessive deformational force which were compression and stiffening of tissue; 2) the high tension skin covering keloid prone areas had low stretch and a low elastic modulus; 3). protruding hard connective tissue such as bony prominences or cartilage into the dermis of keloid prone skin; 4) contractile forces exerted by wound healing fibroblastic cells; and 5) external forces. Compression and occlusion of blood vessels induced ischaemic and reperfusion tissue injury. During the reperfusion phase blood rich in growth factors returned to tissue stimulating tissue growth. Tissue growth was also promoted by elevated internal stress which stimulated increasing levels of gene expression, collagen synthesis and mitotic activity. All these growth promoting effects resulted in keloid formation.
Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2013.