Würzburg, Univ., Diss., 2002.

Made available in DSpace on 2014-10-09T12:35:54Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:26Z (GMT). No. of bitstreams: 0 / Observações feitas pelo próprio autor sugerem potencial ação do Líquido da Castanha de Caju (LCC) na pigmentação da pele, ação esta semelhante a da hidroquinona. O LCC é um líquido contido na casca da castanha de caju, possui característica de resina líquida, bastante viscosa e de odor forte, sua coloração varia de marrom claro, escuro a preto, dependendo do método de extração utilizado, podendo ser denominado de Natural ou Técnico. Este estudo propôs cultivar melanócitos e queratinócitos em cocultura e posteriormente tratálos com LCC. A L-DOPA, agente estimulador da melanogênese, via da produção de melanina, responsável pela pigmentação da pele, foi utilizada na cocultura para avaliar a ação do LCC. A hidroquinona, conhecido inibidor desta via, foi utilizada na cocultura como controle positivo para o LCC, visto que este poderia apresentar ação semelhante a da hidroquinona. Para a utilização do LCC na cocultura, testes de solubilidade do mesmo para posterior dispersão no meio de cultura, foram necessários, bem como a identificação de seu potencial cito e fototóxico in vitro. Para a realização do teste de fototoxicidade foi construída uma câmara específica, atendendo as normas exigidas pelos guias ©ECVAM DB-ALM: INVITTOX protocol e OECD TG-432, sendo esta qualificada por método validado. Os testes realizados com o LCC (natural e técnico) indicaram potencial ação destes na pigmentação da pele, estimulando a proliferação de melanócitos em cocultura. Este perfil apresentado, pelos extratos de LCC, é contrário ao da hidroquinona, e ao esperado inicialmente, sendo necessário aprofundar estes estudos. No entanto, estes resultados são promissores, sugerindo a descoberta de um novo tratamento para hipocromias. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Orientador: Maria Beatriz Puzzi, Maria Helena Stangler Kraemer / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-04T03:54:34Z (GMT). No. of bitstreams: 1 Souto_LuisRicardoMartinhao_M.pdf: 2402921 bytes, checksum: a79b6ae181ce1b24d01ec608815d8bf7 (MD5) Previous issue date: 2005 / Resumo: A obtenção de uma pele humana que apresente derme e epiderme, reconstruída a partir de células isoladas de pacientes, possibilita a realização de enxertos autólogos de pele reconstruída em laboratório (in vitro) em pacientes com áreas doadoras escassas além de permitir ensaios com substâncias químicas e drogas in vitro e não mais in vivo. A partir da cultura de fibroblastos humanos, é possível obter um número suficiente de células que podem ser injetadas em uma matriz de colágeno bovino tipo I que, mantida imersa em meio de cultura, específico para fibroblastos, permite a formação de uma derme humana reconstruída in vitro. Sobre essa derme, através de cultura de queratinócitos e melanócitos humanos, forma-se uma epiderme diferenciada levando à formação de uma pele humana reconstruída in vitro, constituída de derme e epiderme associadas. Essa pele humana formada é, histologicamente, semelhante à pele humana in vivo. Na derme, identifica-se o tecido colágeno, com suas células, e a matriz extracelular organizados paralelamente à epiderme. Esta se desenvolve em várias camadas. Não há distinção entre derme e epiderme no experimento controle, onde não foi utilizado o colágeno bovino tipo I / Abstract: The technique to obtain human skin presenting dermis and epidermis reconstructed from cells isolated from patients allows the performance of autologous grafts of skin reconstructed in laboratory (in vitro) on patients with scarce donor sites, in addition to permitting trials with chemical substances and drugs no more in vivo, but in vitro. It is possible to obtain a sufficient number of cells from human fibroblast culture that can be injected in bovine collagen type I matrix and kept submerged in a specific culture medium for fibroblasts. This will permit the formation of human dermis reconstructed in vitro. On this dermis, through culture of human keratinocytes and melanocytes, a differentiated epidermis is formed, leading to the creation of human skin reconstructed in vitro, composed of associated dermis and epidermis. This human skin is histologically formed in the same way as human skin in vivo. Collagen tissue can be identified in the dermis, with its cells and extracellular matrix organized in parallel to the epidermis, which is developed in several layers / Mestrado / Patologia Clinica / Mestre em Ciências Médicas

L’interaction épithélium/mésenchyme est cruciale pour de nombreux processus physiopathologiques. Lors de ma thèse, je me suis intéressée aux signaux mésenchymateux régulant les cellules épithéliales en utilisant comme modèle la peau, qui est composée de 2 compartiments : l’épiderme (épithélium) et le derme (mésenchyme). Les intégrines sont impliquées ces interactions. CD98hc est une protéine transmembranaire à double fonction qui chaperonne des transporteurs d’acides aminés et régule la signalisation des ß intégrines. Elle est exprimée dans les cellules prolifératives telle les cellules épithéliales. Dans la peau, CD98hc est exprimée l’épiderme mais également dans les fibroblastes, cellules post-mitotiques. Mon hypothèse a été que CD98hc participe aux régulations des interactions derme/épiderme. Grâce à un modèle de KO conditionnel de CD98hc dans les fibroblastes dermiques, j’ai mis en évidence que CD98hc permet le maintient des propriétés mécaniques et biologiques du derme, et, de ce fait, régule l’épiderme en conditions d’homéostasie, de perturbation de la barrière et lors de la formation de cancer. De plus, le rôle de CD98hc dans cette interaction apparait comme étant lié à l’âge. En conclusion, mes travaux de thèse montrent le rôle central de l’expression dermique de CD98hc dans le maintien de l’homéostasie cutanée au cours du vieillissement ainsi que lors de la tumorigenèse. / The epithelial/mesenchymal interaction is crucial for many physiopathological processes. During my PhD, I focused on mesenchymal signals that regulate epithelial cells behavior using the skin as model. The skin is composed of 2 main compartments: the epidermis (epithelium) and the dermis (mesenchyme). While this crosstalk involves integrins, its regulations are poorly understood. The transmembrane protein CD98hc interacts with amino acid transporter and regulates integrin signaling. CD98hc which is expressed at the cell membrane of proliferative cells, specifically epithelial cells, is required for tissue homeostasis. We found that besides its expression in keratinocytes, CD98hc is also expressed in post-mitotic dermal fibroblast. Hence, I hypothesized that CD98hc is involved in epidermis/dermis crosstalk. Using a conditional KO mouse model that harbor a CD98hc deletion in dermal fibroblast, I have shown that dermal CD98hc is required to maintain mechanical and biochemical properties of the dermis. Moreover, I have shown that those CD98hc-dependent dermal properties are implicated in the regulation of the epidermal cell behavior during homeostasis, cutaneous barrier disruption and tumorigenesis. Moreover, the role of CD98hc in those processes seems to be age-related. To conclude, during my PhD, I have revealed a major role of CD98hc in the maintenance of skin homeostasis during aging and tumorigenesis.

Characters of scale surface microstructure are combined with 'traditional' morphological characters in a phylogenetic analysis of the Tropidurini. Tropidurid lizards show variation in types of coarse and fine scale surface microstructure, in the anatomical distribution of different scale surface features, and in scale organ morphology and distribution. The morphology of the inner surface zone of scales is here described for the first time using scanning electron microscopy. Our phylogeny differs considerably from those proposed in earlier studies. New characters and frequency coding of polymorphic characters help resolve the problematic relationships of several species. Statistical confidence supports recognition ot one large cis-Andean and one large trans-Andean clade of species. Based on our results, we synonymize Plesiomicrolophus with Microlophus and Uranoscodon with Tropidurus. The phylogenetic relationships of newly discovered Tropidurus are resolved: T. callathelys is the sister species of T. melanopleurus; T. xanthochilus is the sister species of T. spinulosus. Tropidurus spinulosus is found to be more closely related to T. strobilurus and a clade of Amazonian species than to T. melanopleurus. The species previously placed in Uracentron are more closely related to species previously placed in Plica than to T. strobilurus as previously thought.

No / The human epidermis holds the full machinery for cholinergic signal transduction. However, the presence of the vesicular transporter (vesicular acetylcholine (ACh) transporter (VAChT)) for both choline and ACh has never been shown in this compartment. The results of this study confirm the presence of VAChT in cutaneous nerves and in both epidermal melanocytes and keratinocytes as well as in their nuclei using immunofluorescence labelling in situ and in vitro, Western blot analysis of cellular and nuclear extracts and reverse transcription-PCR. These results underline that ACh/choline transport in the non-neuronal epidermis is no different from the neuronal pathway. However, the function of VAChT in the nucleus remains to be shown.

No / The human epidermis holds an autocrine acetylcholine production and degradation including functioning membrane integrated and cytosolic butyrylcholinesterase (BuchE). Here we show that BuchE activities increase 9-fold in the presence of calcium (0.5 × 10-3 M) via a specific EF-hand calcium binding site, whereas acetylcholinesterase (AchE) is not affected. 45Calcium labelling and computer simulation confirmed the presence of one EF-hand binding site per subunit which is disrupted by H2O2-mediated oxidation. Moreover, we confirmed the faster hydrolysis by calcium-activated BuchE using the neurotoxic organophosphate O-ethyl-O-(4-nitrophenyl)-phenylphosphonothioate (EPN). Considering the large size of the human skin with 1.8 m2 surface area with its calcium gradient in the 10¿3 M range, our results implicate calcium-activated BuchE as a major protective mechanism against suicide inhibition of AchE by organophosphates in this non-neuronal tissue

Yes / Melanin is the predominant pigment responsible for skin colour, and is synthesized by the melanocyte in the basal layer of the epidermis and then transferred to surrounding keratinocytes. Despite its optical properties, melanin is barely detectable in unstained sections of human skin. However, identification and localization of melanin is of importance for the study of skin pigmentation in health and disease. Current methods for the histologic quantification of melanin are suboptimal, and are associated with significant risk of misinterpretation. The aim of this study was to re-assess the existing literature, and to develop a more effective histological method of melanin quantification in human skin. Moreover, we confirm that Warthin-Starry (WS) stain provides a much more sensitive and more specific melanin detection method than the common-place Fontana-Masson (FM) stain. For example, WS staining sensitivity allowed the visualization of melanin even in very pale Caucasian skin that was missed by FM or Von Kossa (VK) stains. From our re-assessment of the histologyrelated literature we conclude that so-called ‘melanin dust’ is most likely an artefact of discoloration due to non-specific silver deposition in the stratum corneum. Unlike FM and VK, WS was not associated with this non-specific stratum corneum darkening, misinterpreted previously as ‘degraded’ or so-called ‘dust’ melanin. Finally, WS melanin particle counts were largely similar to manual counts by transmission electron microscopy, in contrast to both FM and VK. Together these findings allow us to propose a new histology/Image J-informed method for the accurate and precise quantification of epidermal melanin in skin.

Yes / Background: Melanin is synthesized by melanocytes in the basal layer of the epidermis. When transferred to surrounding keratinocytes it is the key UVR-protective biopolymer responsible for skin pigmentation. Most melanin is observable in the proliferative basal layer of the epidermis, and only sparsely distributed in the stratifying/differentiating epidermis. The latter has been explained, despite formal evidence, to ‘melanin degradation’ in supra-basal layers. Objectives: Our aim was to re-evaluate this currently-accepted basis for melanin distribution in the human skin epidermis, and whether this pattern is altered after a regenerative stimulus. Methods: Normal epidermis of adult human skin, at rest and after tape-stripping, was analysed by a range of (immuno)histochemical and high-resolution microscopy techniques. In vitro models of melanin granule uptake by human keratinocytes were attempted. Results: We propose a wholly different fate for melanin in the human epidermis. Our evidence indicates that the bulk of melanin is inherited only by the non-differentiating daughter cell post mitosis in progenitor keratinocytes, via asymmetric organelle inheritance. Moreover, this preferred pattern of melanin distribution can switch to a symmetric or equal daughter cell inheritance mode under conditions of stress including regeneration. Conclusions: We provide in this preliminary report a plausible and histologically-supportable explanation for how human skin pigmentation is efficiently organized in the epidermis. Steady state epidermis pigmentation may involve much less redox-sensitive melanogenesis than previously thought, and at least some pre-made melanin may be available for re-use. The epidermal-melanin unit may be an excellent example to study organelle distribution via asymmetric or symmetric inheritance in response to micro-environment and tissue demands. / Walgreens Boots Alliance

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