Dissertations / Theses on the topic 'Skin – Histology'

There are 5 distinct aspects to this study. (i) Two histological stains for collagen were compared against each other for the first time, namely Herovici's technique and picrosirius-polarization. (ii) Skin samples from embalmed cadaveric tissue from human cadavers were compared against samples taken from surgical patients. (iii) Skin samples were studied from different regions of the body to assess if dermal structure correlates with scarring potential. (iv) Skin samples were sectioned in a plane parallel to the epidermis to gain further insight into dermal structure. (v) A novel basement membrane stain was produced. Type I and type III collagen are important structural constituents of dermis and play a crucial role in wound healing. Only two traditional histological methods are thought to differentiate between them, so avoiding the need for antibodies. These were compared against each other for the first time in order to establish differences in image quality and discrimination between Type I and type III collagen. Neither technique requires antibodies, however picrosirius requires polarisation microscopy. to result in a clearer, consistently reproducible collagen staining pattern than the picrosirius method and more importantly did not require elaborate apparatus to analyze. Additionally other cellular elements were visible. Skin samples for research are often obtained from surgical excision. This clearly limits which tissues are available for comparative study to those areas operated on. Studying samples from embalmed medical school cadavers has the great advantage of studying areas of the body not routinely available from common surgical procedures. It was therefore desirable to assess whether embalmed cadaveric tissues exhibited different properties by virtue of their age and the embalming process compared to fresh surgical specimens, in order to give confidence that studies utilising the former would be equally valid. To test this, 58 skin samples from embalmed medical school cadavers were compared to skin samples from 38 fresh operative specimens. The levels of tissue preservation and processing artefacts were similar in both groups. Embalmed medical school cadavers clearly offer an opportunity to study tissue areas not routinely available during surgery. This is the first time such a comparison has been made. Many things will affect the final appearance of the scar, but the single most important determinant is the body region affected. The most common areas for unfavourable scarring, specifically keloid or hypertrophic scarring have been shown to be the ear, deltoid and sternal areas. To test the hypothesis that there is no difference in histological structure of skin that correlates to body region, comparative histology was undertaken exploring the regional variations of skin characteristics in 58 cadaveric samples. Closely comparable samples were taken from the deltoid (9), abdomen (13), sternum (10), post-auricular (5), earlobe (12) and eyelid (9). Epidermal thickness, epidermal appendage density and collagen fibre orientation were examined and qualitative structural differences were assessed for each region Skin samples were then grouped by both topographical location of the body and scarring potential. Skin samples exhibited qualitative and quantifiable regional variations in the characteristics studied. Epidermal thickness and appendage counts did not correlate with scarring potential. Both however were statistically significantly higher in skin sampled from the head compared to the trunk. Bundles of collagen fibres in the reticular dermis were grouped according to their orientation in relation to the coronal plane; either parallel, oblique or perpendicular. The ratio of oblique to parallel fibres was statistically significantly higher in body areas with poorer scarring prognosis. This corresponds to a more disorganised arrangement of collagen fibres in these areas. Further qualitative understanding of dermal collagen fibres came from perpendicular to conventional histological samples. This new method stained basement membranes purple, cytoplasm was stained greenish-brown and nuclei dark brown. Collagen fibres were either thin and blue or thick and green. This method was compared to PAS staining and although required more preparative steps allows greater identification of other cellular structures.

Made available in DSpace on 2014-06-11T19:27:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-10Bitstream added on 2014-06-13T19:57:01Z : No. of bitstreams: 1 faria_naa_me_jabo.pdf: 988884 bytes, checksum: e245203de1795a549f7fa9d970a31585 (MD5)<br>Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>Com o objetivo de fornecer subsídios para futuras pesquisas sobre aclimatação de equinos criados em clima tropical, um estudo sobre os aspectos histológicos e morfométricos da pele e anexos cutâneos de equinos de duas raças distintas foi realizado. Foram retiradas amostras do tegumento de 20 equinos (10 Árabes e 10 Quartos de Milha), em três regiões corporais distintas (cervical, flanco e glútea). As amostras foram submetidas ao processamento histológico de rotina. Utilizando um sistema de análise de imagens, foram quantificados e ou mensurados ductos sudoríparos, glândulas sebáceas, folículos pilosos e epiderme. Quanto aos aspectos morfométricos, foram encontradas diferenças (p≤0,05) nos parâmetros raça e região corporal. O tegumento de equinos Árabe e Quarto de Milha apresentou constituição histológica semelhante, nas três regiões analisadas<br>Aiming to provide subsidies for future research on acclimation of horses raised in tropical climate, we studied out this work on the histological and morphometric aspects of the skin and skin appendages of two distinct horses races. Skin samples were taken from 20 horses (10 Arabian and 10 Quarter Horses), in three different body regions (neck, flank and gluteus). Samples were analysed using a routine histological process. Through a system of image analysis, we quantified and measured or sweat ducts, sebaceous glands, hair follicles and epidermis. Morphometric differences were found (p ≤ 0.05) in race and body region parameters. Arab horses and Quarter Horses skin presented similar histological composition in the three analyzed regions

This project examined the role of the cytoskeleton in regulatory mechanisms of the amiloride-sensitive Na⁺ channels in isolated frog skin epithelium. The epithelium from ventral frog skin is a model tissue which has proved significant in our understanding of the basic principles involved in water and Na⁺ homeostasis. In particular, this project examines ways in which local (non-hormonal) and hormonal regulatory mechanisms adjust the Na⁺ permeability of apical membranes of frog skin epithelium. Both mechanisms contain factors that are known to increase the apical membrane Na⁺ permeability mainly by increases in the number of open channels. The origin of these new open channels is unknown but, it is postulated that they could arise either by activation of quiescent channels already present in the apical membrane, or by recruitment of channels from cytoplasmic stores. Regarding the latter hypothesis, we also examined the idea that the cytoskeleton might somehow be involved in the insertion of Na⁺ channels within vesicles, into the apical membrane. This is based on the fact that the cytoskeleton is involved in a similar mechanism whereby, in the toad urinary bladder, anti-diuretic hormone (ADH) causes the insertion of aggregates with water channels. Much current interest focuses on the role of the cytoskeleton in the regulation of epithelial Na⁺ channels. To test this hypothesis, we used noise analysis to examine the effects of disrupting the cytoskeleton, on two different mechanisms which bring about changes in open channel densities. The mechanisms are: (1) lowering mucosal Na⁺ concentration (non-hormonal), and (2) addition of arginine-vasopressin (A VP) (hormonal). Non-hormonal, autoregulatory changes in apical membrane Na⁺ conductance were examined by investigating the effects of reducing the mucosal Na⁺ concentration. Our results showed that lowering the mucosal Na⁺ concentration induced large increases in the open channel density in order to stabilise the transport rate. In addition, we observed an average 55-60% increase in the open channel probability, which implies that in epithelium from Rana fuscigula, changes of channel open probability are also an important mechanism in the autoregulation of channel densities in response to a reduction in mucosal Na⁺. The hormonal control of Na⁺ channels by A VP has been intensively studied by noise analysis and the patch clamp. Our results confirmed previous reports that A VP increases the Na⁺ transport rate by increasing the number of open Na⁺ channels, primarily through large changes in the total number of channels, without a significant change in open probability. Regarding the role of the cytoskeleton in regulation of Na⁺ channels and/or its possible role in control of inserting putative vesicles with Na⁺ channels, we studied the effects of disrupting the cytoskeleton on the two regulatory mechanisms. Disrupting microtubules with colchicine had no, or very little effect on either of the regulatory mechanisms. On the other hand, the integrity of the microfilaments was very important for the autoregulatory changes in the number of open channels. After cytochalasin B treatment, lowering the mucosal Na⁺ concentration did not result in the usual compensatory changes in channel densities. There was no prior evidence that cytochalasin B had any actual effect on the F-actin network in the frog skin epithelium. Accordingly, modified cytochemical techniques were designed to demonstrate and localise F-actin in the epithelial granular cells. The direct immunofluorescent method proved useful, but did not allow sufficient resolution to examine the changes to different populations of actin in the cells. We then modified an immunogold method to suit our conditions, and the results demonstrated the localisation of different pools of F-actin and showed the effects of the cytochalasin B and vasopressin.

Thesis (MSc)--University of Stellenbosch, 2002.<br>ENGLISH ABSTRACT: Specialized skin scales (generation glands) and undifferentiated skin scales were compared in three species of cordylid lizard, viz. Cordy/us cordy/us, Pseudocordy/us micro/epidotus and P. capensis. These skin derivatives were histologically examined and compared, using data existing in literature (Maderson, 1966; 1967; 1968a) with similar structures in gekkonids. Histological descriptions of cordylid skin structure were the same as those shown for gekkonids. Three types of generation glands were identified in cordylids (Van Wyk & Mouton, 1992), and these proved to be different to those existing in gekkonid species. These three types of generation glands were further compared regarding their ecdysis histology, which proved to be identical, thus, these glands differ only on gross morphological structure. Skin of all three species was also compared with regard to ecdysis, and while the histology of all three was identical, shedding activity was shown to differ in all three species. P. micro/epidotus displayed dormancy in the germinative layer for much longer periods of the year than either of the other two species, while P. capensis displayed very little dormancy. C. cordy/us displayed an intermediate pattern of ecdysis activity and dormancy. Autoradiography was performed on all species in both ecdysis activity and dormancy periods, to compare mitotic activity patterns in these periods. Generation gland activity appeared to correlate well with known testosterone peaks in the testicular cycle in all three species. Asynchrony between generation glands and skin scales was shown in all three species.<br>AFRIKAANSE OPSOMMING: GENERASIEKLIERE EN VERVELLINGSIKLUSSE IN GORDELAKKEDISSE (SAURIA: CORDYLIDAE) Drie spesies gordelakkedisse, Gordy/us cordy/us, Pseudocordy/us micro/epidofus en P. capensis, se gespesialiseerde velskubbe (generasiekliere) en gewone velskubbe word vergelyk. Hierdie velskubbe word deur histologiese metodes geëksamineer en vergelyk, met gebruik van data wat reeds in die literatuur bestaan (Maderson, 1966; 1967; 1968a), met soortgelyke strukture in Gekkonidae. Histologiese beskrywing van Cordylidae veistruktuur was identies met dié van Gekkonidae. Drie tipes generasiekliere was geïdentifiseer in gordelakkedisse (van Wyk & Mouton, 1992), en hulle verskil gedeeltlik van naverwante strukture in Gekkonidae. Hierdie drie tipes generasiekliere was verder vergelyk met betrekking tot hulle vervellingsiklus histologie, wat identies was. Dus verskil hulle net met betrekking tot hulle vorm. Vel is ook vergelyk met dieselfde metodes. Alhoewel daar geen verskille was met betrekking tot hulle histology nie, was die tye van aktiwiteit van kiem-sellae beduidend verskillend in alle spesies. In P. micro/epidofus het die kiem-sellaag russtadium baie langer geduur as in die ander twee spesies, terwyl P. cepensis amper geen russtadium getoon het nie. G. cordy/us het 'n intermediêre gedragspatroon vertoon tussen aktiewe en rustende fase met betrekking tot sy vervellingsiklus. Outoradiografie is gebruik op elke spesie, in beide aktiewe en rustende vervellingsfases, om verskille in mitotiese aktiwiteit te wys. Generasieklier aktiwiteit blyk te korreleer met pieke van testosteroonvlakke van die testikulêre siklus in al drie spesies. Asinkronie is aangetoon tussen generasiekliere en velskubbe in al drie spesies.

Orientador: Marcos Lania de Araujo<br>Banca: Marcia Rita Fernandes Machado<br>Banca: Joffre Guazzelli Filho<br>Resumo: Com o objetivo de fornecer subsídios para futuras pesquisas sobre aclimatação de equinos criados em clima tropical, um estudo sobre os aspectos histológicos e morfométricos da pele e anexos cutâneos de equinos de duas raças distintas foi realizado. Foram retiradas amostras do tegumento de 20 equinos (10 Árabes e 10 Quartos de Milha), em três regiões corporais distintas (cervical, flanco e glútea). As amostras foram submetidas ao processamento histológico de rotina. Utilizando um sistema de análise de imagens, foram quantificados e ou mensurados ductos sudoríparos, glândulas sebáceas, folículos pilosos e epiderme. Quanto aos aspectos morfométricos, foram encontradas diferenças (p≤0,05) nos parâmetros raça e região corporal. O tegumento de equinos Árabe e Quarto de Milha apresentou constituição histológica semelhante, nas três regiões analisadas<br>Abstract: Aiming to provide subsidies for future research on acclimation of horses raised in tropical climate, we studied out this work on the histological and morphometric aspects of the skin and skin appendages of two distinct horses races. Skin samples were taken from 20 horses (10 Arabian and 10 Quarter Horses), in three different body regions (neck, flank and gluteus). Samples were analysed using a routine histological process. Through a system of image analysis, we quantified and measured or sweat ducts, sebaceous glands, hair follicles and epidermis. Morphometric differences were found (p ≤ 0.05) in race and body region parameters. Arab horses and Quarter Horses skin presented similar histological composition in the three analyzed regions<br>Mestre

The skin is the largest organ of the body and provides many functions. Among tetrapod vertebrates, amphibian skin is semi-permeable and responsible for a greater proportion of water absorption and gas exchange. Myriad factors affect the physiological performance of amphibian skin. Morphological traits linked with amphibian skin physiology or ecology have remained difficult to discern because of a lack of quantitative comparative research and the discovery of sources of intraspecific variation that are mostly ignored in study designs. This thesis aims to address the effects of these sources of variation using a trait that is known to vary between sexes, among seasons, and among body regions and thought to be linked with physiology or ecology, skin thickness. The first source of variation addressed is sexual dimorphism. Specimens of the white-lipped treefrog, Litoria infrafrenata, that display sexual dimorphism in body size and skin thickness were used to test if body size was the main determinate of sexually dimorphic skin thickness. Size corrected values did not significantly differ between males and females, although the sample size was small. Seasonal variation in skin thickness has also been documented in some species, so the American bullfrog (Lithobates catesbeianus), the Northern leopard frog (L. pipiens), and the spring peeper (Pseudacris crucifer) from multiple months of the year were sampled to determine if skin thickness increased in the autumn or winter months. Seasonal skin thickening was only detected in L. catesbeianus, and skin from autumn and winter was significantly thicker than from earlier in the year. This pattern was also detectable in museum specimens collected 80 years ago, although the signal was damped, possibly due to preservation. Using a dataset of 10 species and published data, a general pattern was uncovered whereby the dorsal skin is the thickest region and the ventral thigh region is the thinnest. However, this pattern is not always true for every individual of every species (L. pipiens and P. crucifer) and in some species the dorsal skin is thinnest (Bokermannohyla alvarengai and Litoria infrafrenata). The same dataset found that skin thickness is significantly related to body size, as was found in the chapter on Litoria infrafrenata. Summer specimens of Lithobates catesbeianus were outliers below the interspecific regression line and winter specimens fell within the range of variation of other species, hinting that seasonal skin thickening could be renamed seasonal skin thinning in this species. Finally, a link between ecology and skin thickness was tested using the 10 species from previous analyses and data from the literature. At a phylogenetially broad scale, body size explained a greater amount of the variation in environmental parameters than skin thickness. At smaller taxonomic scales, skin thickness appears more closely linked with ecology. It is concluded that amphibians generally follow an allometric trend for skin thickness and when faced with suboptimal conditions over long periods of time, evolve integumentary structures like iridiophores to compensate for any physiological disadvantage of an ‘ideal’ skin thickness. In the interim, however, skin thickness may change, thus sacrificing e.g. mechanical support.

Made available in DSpace on 2014-10-09T12:35:35Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:04:00Z (GMT). No. of bitstreams: 0<br>Tese (Doutoramento)<br>IPEN/T<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Tissue regeneration in salamanders is a robust process that is not easily interrupted or altered. Therefore, inhibiting regeneration provides a means to interrogate the underlying cellular and molecular mechanisms regulating this complex event. Here we show that application of a relatively low concentration of beryllium nitrate solution (100mM) causes a delay in skin regeneration and severely alters normal limb regeneration. We provide evidence showing a beryllium-induced reduction in dermal fibroblast migration in vivo and in vitro. We link this phenomenon to delayed regeneration of the skin and abnormal blastema formation resulting in limb patterning defects during regeneration. Though our results show a slight reduction in fibroblast proliferation during the early stages of limb regeneration, we attribute this to an overall reduction in fibroblast presence at the site of injury. Keratinocytes appeared unresponsive to beryllium treatment with the rates of re-epithelialization and proliferation not significantly different between treatment and control groups. Taken together, these data reinforce a necessary role for fibroblasts during tissue regeneration and show that beryllium nitrate inhibits normal fibroblast behavior.

Made available in DSpace on 2014-10-09T12:52:32Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:02:37Z (GMT). No. of bitstreams: 0<br>Dissertação (Mestrado)<br>IPEN/D<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-06-11T19:23:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-19Bitstream added on 2014-06-13T19:30:09Z : No. of bitstreams: 1 isola_jgmp_me_jabo.pdf: 3165720 bytes, checksum: f8e7a45bb499548ba3c06fc07e342764 (MD5)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>Considerando-se a falta de informações detalhadas sobre a morfologia da paca e dada a importância do tegumento comum, descreveu-se a morfologia, morfometria e a ultraestrutura da pele de oito pacas (Cuniculus paca) machos e fêmeas, mediante a análise comparativa de segmentos cutâneos das regiões cervical, dorsal, medial do carpo e coxins palmares e plantares. Observaram-se macroscopicamente as características da pelagem. Parte dos segmentos das regiões cutâneas foi analisado à microscopia de luz e parte, à microscopia eletrônica de varredura. Mensuraram-se as espessuras da derme, epiderme, camada córnea, fibras de colágeno da derme reticular; área das células das glândulas sebáceas repletas, exceto nos coxins, onde se verificaram as espessuras da derme, epiderme e camada córnea. Analisaram-se os resultados pela estatística descritiva e teste “T” (p=0,00). A coloração da pelagem da paca é castanho avermelhado e os pelos organizados em grupos. A epiderme apresenta as camadas basal, espinhosa, granular e córnea, bem delimitadas; os coxins apresentam ainda, a camada lúcida. A derme constituía-se pelas camadas: papilar e reticular, com pelos e glândulas. Com exceção da área das células das glândulas sebáceas repletas, a espessura de todas as estruturas avaliadas apresentou-se maior nos machos, quando comparados com as fêmeas. A espessura da derme, da camada córnea da epiderme, das fibras colágenas da camada reticular da derme, além da área das células das glândulas sebáceas repletas foram maiores na região cervical. A região medial do carpo apresentou maior espessura total da epiderme. Em relação aos coxins verificou-se que a espessura da derme do coxim plantar era significativamente maior do que a do coxim palmar...<br>Considering the lack of detailed information on the morphology of Paca and the importance of the common integument, this study described the morphology, morphometry and ultrastructure of the skin of eight Pacas (Cuniculus paca) four male and four female, through comparative analysis of the following segments skin regions: cervical, dorsal, medial carpal and footpads. The characteristics of the coat were observed macroscopic. Some of the segments of skin regions were analyzed by light microscopy and the other part by the scanning electron microscopy. Were measured thickness of the dermis, epidermis, stratum corneum, collagen fibers of the reticular dermis and the area of cells of the sebaceous glands filled, except in the footpads, which were analyzed the thickness of the dermis, epidermis and stratum corneum also. We analyzed the results using descriptive statistics and t test (p < 0,001). The color of the paca’s coat is reddish brown and the hair arranged in groups. The epidermis have the basal, spinous, granular and horny stratum, well-defined, the footpads have in addiction the lucid stratum. The dermis is constituted by layers: papillary and reticular, hairs and glands. Aside from the area of the cells of the sebaceous glands filled, the thickness of all the structures evaluated were higher in males when compared with females. The thickness of the dermis, stratum corneum of the epidermis, the collagen fibers of the reticular dermis, and the area of the cells of the sebaceous glands are more crowded in the neck. The medial carpal region showed greater total thickness of the epidermis. For the cushions was found that the thickness of the dermis of the hind footpad was significantly greater than that of the fore... (Complete abstract click electronic access below)

Resumo: Considerando-se a falta de informações detalhadas sobre a morfologia da paca e dada a importância do tegumento comum, descreveu-se a morfologia, morfometria e a ultraestrutura da pele de oito pacas (Cuniculus paca) machos e fêmeas, mediante a análise comparativa de segmentos cutâneos das regiões cervical, dorsal, medial do carpo e coxins palmares e plantares. Observaram-se macroscopicamente as características da pelagem. Parte dos segmentos das regiões cutâneas foi analisado à microscopia de luz e parte, à microscopia eletrônica de varredura. Mensuraram-se as espessuras da derme, epiderme, camada córnea, fibras de colágeno da derme reticular; área das células das glândulas sebáceas repletas, exceto nos coxins, onde se verificaram as espessuras da derme, epiderme e camada córnea. Analisaram-se os resultados pela estatística descritiva e teste "T" (p=0,00). A coloração da pelagem da paca é castanho avermelhado e os pelos organizados em grupos. A epiderme apresenta as camadas basal, espinhosa, granular e córnea, bem delimitadas; os coxins apresentam ainda, a camada lúcida. A derme constituía-se pelas camadas: papilar e reticular, com pelos e glândulas. Com exceção da área das células das glândulas sebáceas repletas, a espessura de todas as estruturas avaliadas apresentou-se maior nos machos, quando comparados com as fêmeas. A espessura da derme, da camada córnea da epiderme, das fibras colágenas da camada reticular da derme, além da área das células das glândulas sebáceas repletas foram maiores na região cervical. A região medial do carpo apresentou maior espessura total da epiderme. Em relação aos coxins verificou-se que a espessura da derme do coxim plantar era significativamente maior do que a do coxim palmar... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Considering the lack of detailed information on the morphology of Paca and the importance of the common integument, this study described the morphology, morphometry and ultrastructure of the skin of eight Pacas (Cuniculus paca) four male and four female, through comparative analysis of the following segments skin regions: cervical, dorsal, medial carpal and footpads. The characteristics of the coat were observed macroscopic. Some of the segments of skin regions were analyzed by light microscopy and the other part by the scanning electron microscopy. Were measured thickness of the dermis, epidermis, stratum corneum, collagen fibers of the reticular dermis and the area of cells of the sebaceous glands filled, except in the footpads, which were analyzed the thickness of the dermis, epidermis and stratum corneum also. We analyzed the results using descriptive statistics and t test (p < 0,001). The color of the paca's coat is reddish brown and the hair arranged in groups. The epidermis have the basal, spinous, granular and horny stratum, well-defined, the footpads have in addiction the lucid stratum. The dermis is constituted by layers: papillary and reticular, hairs and glands. Aside from the area of the cells of the sebaceous glands filled, the thickness of all the structures evaluated were higher in males when compared with females. The thickness of the dermis, stratum corneum of the epidermis, the collagen fibers of the reticular dermis, and the area of the cells of the sebaceous glands are more crowded in the neck. The medial carpal region showed greater total thickness of the epidermis. For the cushions was found that the thickness of the dermis of the hind footpad was significantly greater than that of the fore... (Complete abstract click electronic access below)<br>Orientadora: Márcia Rita Fernandes Machado<br>Coorientadora: Paola Castro Moraes<br>Banca: Gilson Hélio Toniollo<br>Banca: Sheila Canevese Rahal<br>Mestre

O presente estudo teve como objetivo caracterizar as alterações histológicas de pele, linfonodo e baço, determinar a densidade de parasitas e de células iNOS+, assim como correlacionar o parasitismo com a expressão de iNOS em pele, baço e linfonodo de cães naturalmente acometidos por leishmaniose visceral. Foram selecionados aleatoriamente, 28 cães infectados com Leishmania (Leishmania) infantum chagasi, oriundos do Centro de Controle de Zoonoses do município de Araçatuba, os quais foram distribuídos em dois grupos, de acordo com sinais clínicos e exames laboratoriais, em sintomáticos (n=18) e assintomáticos (n=10). Um grupo de 6 animais oriundos de área não endêmica para leishmaniose visceral foram empregados como controle negativo. As alterações histológicas de pele foram similares em ambos os grupos clínicos, sintomáticos e assintomáticos, e se caracterizaram por um infiltrado inflamatório na derme, formado por células mononucleares (macrófagos, linfócitos e plasmócitos), que variou de discreto a intenso. No linfonodo, as alterações histológicas foram também semelhantes entre os grupos clínicos, e se caracterizaram por hiperplasia e hipertrofia da área cortical e para-cortical, que variou de discreta a intensa; e por hiperplasia e hipertrofia de macrófagos na região medular, caracterizando em muitos casos uma linfadenite granulomatosa. No baço, alterações histológicas da polpa branca e polpa vermelha foram similares entre os grupos sintomáticos e assintomáticos, com hipoplasia e atrofia de polpa branca e, hipertorfia e hiperplasia de macrófagos na polpa vermelha, variando de moderado a intenso. Quanto ao número de formas amastigotas/mm2 tanto na pele, como no linfonodo e baço, não houve diferença estatisticamente significativa entre os grupos clínicos (p=0,2104), (p=0,2401) e (p=0,8869), respectivamente. Em relação à densidade de células iNOS+(células/mm2), observamos que a infecção por Leishmania levou ao aumento do número destas células na pele, no baço e no linfonodo em relação ao controle (p < 0,05). Porém, quando analisamos a densidade de células iNOS+ entre os grupos clínicos, sintomáticos e assintomáticos, não observamos diferença significativa tanto na pele (p=0,3026), como em linfonodo (p=0,3257) e baço (p=0,5940). Observou-se correlação fraca e não significativa entre a densidade de parasitas e a densidade de células expressando iNOS+ no tegumento; porém no linfonodo, verificou-se correlação negativa moderada e significante (p=0,0034) entre o parasitismo e a expressão de células iNOS+, assim como no baço (p=0,0329), sugerindo que o óxido nítrico deve exercer um papel importante no controle do parasitismo em vísceras<br>The present study aimed the characterization the histological features in skin, lymph nodes and spleen; determination of the parasitism density and the cells expressing iNOS; and correlation between the parasitism and the expression of iNOS in the skin, lymph nodes and spleen of dogs naturally committed by visceral leishmaniasis. Twenty-eight naturally infected dogs by Leishmania (Leishmania) infantum chagasi were selected randomly from the Zoonosis Control Center of Araçatuba municipality and distributed in two groups according to the clinical signs and laboratory exams, symptomatic (n=18) and asymptomatic (n=10) animals. A group of six animals from non-endemic region for visceral leishmaniais was used as negative control. Histological changes in skin were similar in both clinical groups, symptomatic and asymptomatic, and were characterized by a focal and diffuse inflammatory infiltrate in the dermis of mononuclear cells (macrophages, lymphocytes, plasmocytes), that varied from discrete to intense. In lymph nodes, the histological changes were also similar in both clinical groups, and were characterized by hyperplasia and hypertrophy of the cortical and para-cortical area, that varied from discrete to intense; and hyperplasia and hypertrophy of macrophages in the medullar region characterizing in many cases a granulomatous lymphadenitis. In spleen, the histological alterations in the white pulp and red pulp were similar in both clinical groups, with hypoplasia and hypotrophy of the white pulp and hypertrophy and hyperplasia of macrophages in red pulp varying from moderate to intense. Regarding the results of parasitism density (amastigotes/mm2), we did not observe any significant difference between the clinical groups in skin (p=0.2104), lymph nodes (p=0.2401) and spleen (p=0.8869). Concerning to the density of iNOS+ cells, we observed that the infection by Leishmania caused an increase in the number of these cells in the skin, in spleen and lymph nodes in relation to the control group (p < 0.05). However, when we analyzed the density (cells /mm2) of iNOS+ expressing cells in clinical groups, symptomatic and asymptomatic, we did not observe any significant difference in the skin (p=0.3026), in lymph nodes (p=0.3257) and spleen (p=0.5940). A weak and non-significant correlation was observed between the parasite density and the density of iNOS+ cells in the skin. However, in the lymph node a significant and moderate correlation (p=0.0034) was observed between the parasitism and iNOS+ cells, as well as in the spleen (p=0.0329), suggesting that nitric oxide plays an important role in the control of the parasitism in the viscera

Pacientes submetidos ao tratamento cirúrgico da obesidade mórbida apresentam perda ponderal acentuada e dismorfismo corporal e, com frequência, solicitam cirurgias plásticas visando um contorno corporal mais adequado. Os resultados dessas cirurgias plásticas são, em parte, limitados pela qualidade da pele resultante do grande emagrecimento. O presente estudo observacional teve como objetivo comparar fragmentos de pele da região epigástrica de 20 pacientes após perda ponderal acentuada consequente à cirurgia bariátrica com 20 pacientes portadores de obesidade mórbida, no sentido de analisar as alterações estruturais da pele como consequência do emagrecimento. A análise histomorfométrica foi realizada sobre o sistema colagênico através da metodologia Picrossírius/luz polarizada, e sobre o sistema elástico através da metodologia resorcinafucsina de Weigert. Foram observados, a redução das fibras colagênicas grossas (p=0,048); o aumento das fibras colagênicas finas (p=0,0085); e o aumento da densidade das fibras elásticas (p=0,0000009033) no grupo de pacientes emagrecidas. Não houve diferença entre os grupos quanto à média de idades (p=0,917) e quantidade total de fibras colágenas (p=0,3619). Os resultados evidenciaram as alterações estruturais da derme decorrentes do emagrecimento acentuado, demonstradas por meio do remodelamento colagênico, com a consequente redução das fibras espessas, organizadas, estruturadas e direcionadas em prol do aumento de fibras finas, desalinhadas e frouxamente dispostas, isso em associação ao aumento da elasticidade da pele. Isto explica cientificamente a já estabelecida percepção clínica das alterações cutâneas dos pacientes emagrecidos após cirurgias bariátricas, apresentando menor resistência e maior flacidez, quando comparadas ao período anterior ao emagrecimento<br>Post-bariatric patients develop body contour deformities and need plastic surgery procedures for reduction of excess skin and subcutaneous tissue. The results of these contouring procedures are typically limited by the poor quality of the skin. This observational study compared the epigastric skin of 20 post-bariatric with massive weight loss women with 20 women with morbid obesity through histomorphometric analysis of collagen fibers (picrosiriuspolarization) and elastic fibers (Weigert\'s resorcin-fuchsin). A reduction of thick collagen fibers (p=0.048), increase of thin collagen fibers (p=0.0085) and increase of the density of elastic fibers (p=0.0000009) were observed in the group of post-bariatric patients. There was no difference between the groups for mean age (p=0.917) and the total amount of collagen fibers (p=0.3619). These results represent structural changes in the dermis due to the massive weight loss once it demonstrates collagen modifications with reduction of thickness, organized and structured fibers, increase of thin, misaligned and disarranged fibers, and augmentation of the density of elastic fibers. This brings the scientific explanation for the established clinical perception that the skins of post-bariatric patients are less resistant and with more laxity when compared with what they were before the bariatric surgery

O aumento da prevalência da obesidade mórbida constitui um problema de saúde pública global. A obesidade mórbida pode ser definida por um índice de massa corpórea ( IMC ) superior a 35 Kg/ m²; vem acompanhada por diversas comorbidades e determina custos sócio-econômicos elevados. O único método efetivo a longo prazo no tratamento da obesidade mórbida, na atualidade, é a cirurgia bariátrica. Os procedimentos cirúrgicos para tratar a obesidade foram estimulados sobretudo pelo advento de técnicas videolaparoscópicas com menor morbidade pós-operatória e recuperação precoce. O sucesso operatório da cirurgia bariátrica representa perda de até 50% do excesso de peso dos pacientes em prazos variáveis de aproximadamente 24 meses. Após tal período, o processo de emagrecimento será refletido como excesso e flacidez cutânea generalizados e inicia-se a busca pela melhora da imagem corporal. A realização das cirurgias plásticas de contorno corporal exige ampla compreensão das peculiaridades clínicas desse paciente, e dos riscos de complicações, além de expectativas viáveis quanto aos resultados estéticos. Após as cirurgias de contorno corporal, passado o período pós-operatório recente, constata-se a manutenção de flacidez cutânea residual em graus variados. A obesidade interfere na qualidade dos componentes da pele humana. Entretanto, não há estudos específicos em relação à pele do paciente após perda ponderal maciça. Nesse estudo observacional histomorfométrico realizado entre 2006 e 2008, o autor avalia em biópsias de pele humana da região abdominal epigástrica e hipogástrica, o teor de colágeno e elastina em pacientes após perda ponderal maciça comparativamente a pacientes sem antecedentes de obesidade. Analisando a pele abdominal de mulheres não obesas ( controles epigástricos=15 e controles hipogástricos=25 ) e mulheres após tratamento dessa morbidade ( casos=40), verificou-se neste estudo com significância estatística aceita como p<0,05 que: a) na região epigástrica, o teor de colágeno foi superior no grupo controle em comparação ao grupo de casos; b) na região epigástrica, o teor de fibras elásticas foi superior nos casos; c) na região hipogástrica, não houve diferença estatisticamente significante no teor de colágeno entre os grupos estudados; d) na região hipogástrica, o teor de fibras elásticas foi superior no grupo controle<br>Morbid obesity is an increasing health problem and it is defined as a body mass index greater than 35 kg/m² with severe obesity related comorbidity or a body mass index greater than 40 kg/m² without comorbidity. The combined direct and indirect cost of obesity has been elevated. Bariatric surgery remains the only durable option for weight loss in the morbidly obese.Advanced laparoscopy procedures, as less invasive therapy, have contributed to fast recovery and acceptable perioperative morbidity. Results of bariatric surgery can reach about 50% of excess weight loss with a 2 year follow-up. As patients lose weight, they get laxity skin and their interest in body contouring surgery begins.Plastic surgery in massive weight loss patient demands attention to reduce risks and viable expectations concern to aesthetic results. However, after body contouring surgery, patients can keep up some laxity or folds of excess skin. Obesity changes the components of skin, but there arent definitive studies about skin in massive weight loss patients. In this histomorphometric comparative study, biopsies of human female abdominal skin were analysed in quantity of collagen and elastic fibers in controls (non obese patients, epigastric topography n=15 and hypogastric topography n=25 ) in comparison to massive weight loss patients (n=40). After statistical analyses with p<0,05 was demonstrated that: a)in epigastric topography, the quantity of collagen was higher in control group; b) in epigastric topography, the quantity of elastic fibers was higher in case group; c) in hypogastric topography, there werent diferences in the quantity of collagen between cases and controls; d) in hypogastric topography, the quantity of elastic fibers was higher in control group

Made available in DSpace on 2014-10-09T12:45:41Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:07:18Z (GMT). No. of bitstreams: 1 07609.pdf: 2103835 bytes, checksum: daf8a4e12257ed226478079afb3ed0d5 (MD5)<br>Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia)<br>IPEN/D-MPLO<br>Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

Made available in DSpace on 2014-07-29T15:07:56Z (GMT). No. of bitstreams: 1 Dissertacao Caroline Rocha de Oliveira Lima.pdf: 444731 bytes, checksum: f7805c76dff945571aca16f931a7c2a8 (MD5) Previous issue date: 2010-02-25<br>In veterinary medicine, skin injuries represent a significant casuistry and require expensive therapies, considerable recovery time and often lead to unfavorable resolution. To establish an effective therapeutic protocol it is essential that the professional has a solid knowledge of the healing dynamic, as its phases, triggered events, features, as well as about the biological potential of the healing process coadjutants. Regarding these ones, it is known that phytotherapy has a wide range of botanical specimens with healing potential, and, among them, the barbatiman, native species of the Brazilian cerrado, by its antiseptic and astringent activities, becomes an attractive option for skin injures therapies. The chitosan biomaterial also has potential as coadjutant of the process, once it accelerates the triggering of the healing stages by its immunomodulatory property. To clarify the mechanism proposed by these agents, numerous tests are developed using laboratory animals, in order to give reliability to the therapy modality established. To follow clinical evolution in vivo, the clinical examination becomes essential, while morphometric analysis provide accurate data regarding the percentage of centripetal contraction of the lesions. Finally, the microscopic analysis is used to analyze the ultrastructure of the injured site, predominant kinds of cells in each stage and microscopic events triggered on the search for the morphofunctional restoration of the affected tissue. Considering it, with the development of this study it was aimed to evaluate the activity of 5% barbatiman cream (CB) and 5% chitosan cream (CQ) based therapeutic formulations, on the healing process of incisional skin wounds undergone healing by secondary intention, with rabbit as experimental model. In the first chapter it was performed a wide and detailed literature review about the topic of the study, which involved description of the target tissue, skin, hysiopathology of the healing process, barbatiman phytotherapic and chitosan biomaterial activities as healing coadjutants, use of laboratory animals in scientific research and evaluation methods of skin therapies. In the second chapter, it was tested the therapeutic activity of CB and CQ on healing of incisional cutaneous wounds with rabbit as experimental model, by daily clinical evaluation and morphometric analysis performed on days three, seven, 14 and 21 post-injury. There were performed four wounds on each animal, totaling 40 rabbits. Daily, all lesions of each animal received a specific topical therapy, which lasted for 21 consecutive days. First, we performed the antiseptic with 0.9% sodium chloride solution e and further applied treatment protocols themselves. In one of the protocols employed in cream barbatiman (CQ) in another cream chitosan (QC), and these were formulations tests. In the third protocol was the use of allantoin cream (positive control) and finally the cream neutral vehicle (negative control I). In other injury effected only without topical antiseptic and associated 0.9% sodium chloride solution (negative control II). The results showed that the CB and CQ contributed to the satisfactory progress of the healing process. Although there has been no statistical differences in the contraction percentage between the two treatments (CB and CQ), it was clinically observed that the wounds treated with CB showed better clinical responses than CQ. In the third chapter it was comparatively performed, by clinical and microscopic evaluations, the analysis of the action of CQ and CB in the wounds of the same animals that received the treatments from chapter two. For histological analysis, there were considered the predetermined period for morphometry and the samples were evaluated regarding the prevalence of polymorphic and mononuclear infiltrate, presence of necrosis, crust, granulation tissue, fibroplasia, angiogenesis, collagenization and skin reepithelialization. From the results obtained it can be affirmed that the activities attributed to barbatiman and chitosan contributed similarly to the satisfactory progress of the healing process, once both treatments did not differ significantly for any parameter considered in this study. It is suggested that therapeutic protocols chitosan and barbatiman based provided acute inflammation reduction, as much as promoted fibroblast activation, early development of connective tissue, neovascularization and tissue reepithelialization, providing proved effective and economically viable alternatives in the healing process.<br>Na clínica médica veterinária as injúrias cutâneas representam casuística significativa e cursam com terapias dispendiosas, tempo de recuperação considerável e resolução muitas vezes desfavorável. Para instituir um protocolo terapêutico eficaz é imprescindível que o profissional tenha conhecimento sólido da dinâmica cicatricial, como suas fases, eventos desencadeados, particularidades, bem como acerca do potencial biológico dos coadjuvantes do processo cicatricial. Quanto a estes últimos, sabe-se que a fitoterapia possui um leque variado de espécimes botânicos com potencial na cicatrização e dentre estes o barbatimão, espécie nativa do cerrado brasileiro, por suas atividades, antiséptica e adstringente, torna-se opção atraente quanto às terapias das injúrias cutâneas. O biomaterial quitosana também possui potencial como coadjuvante do processo, visto que por sua propriedade imunomoduladora acelera o desencadeamento das fases da cicatrização. Para esclarecer o mecanismo proposto por estes agentes, inúmeros ensaios são desenvolvidos, utilizando animais de laboratório, a fim de conferirem confiabilidade à modalidade terapêutica instituída. Para acompanhar a evolução clínica in vivo, o exame clínico torna-se essencial, enquanto que as análises morfométricas conferem dados precisos quanto ao percentual de contração centrípeta das lesões. Por último as análises microscópicas são empregadas para analisar a ultra-estrutura do sítio lesionado, tipos celulares predominantes em cada fase e eventos microscópicos desencadeados na busca do restabelecimento morfofuncional do tecido acometido. Diante do exposto, com o desenvolvimento desse estudo objetivou-se avaliar a atividade de formulações terapêuticas a base de creme de barbatimão a 5% (CB) e creme e quitosana a 5% (CQ) frente ao processo de cicatrização de feridas cutâneas incisionais submetidas à cicatrização por segunda intenção, tendo o coelho com o modelo experimental. No primeiro capítulo efetuou-se revisão de literatura ampla e detalhada do tema do estudo que envolveu descrição do tecido alvo, pele, fisiopatologia do processo cicatricial, atividade do fitoterápico barbatimão e do biomaterial quitosana como coadjuvantes da cicatrização, emprego de animais de laboratório em pesquisas científicas e métodos de avaliação das terapias cutâneas. No segundo capítulo, testou-se a atividade terapêutica dos CB e CQ na cicatrização de feridas cutâneas incisionais, por meio da avaliação clínica efetuada diariamente e morfométrica nos dias três, sete, 14 e 21 pós-lesão. Foram realizadas quatro feridas em cada animal, totalizando 40 coelhos. Diariamente, todas as lesões de cada animal receberam uma terapia tópica específica, que se estendeu durante 21 dias consecutivos. Primeiramente, realizava-se a antissepsia com solução de cloreto de sódio a 0,9% e na sequência aplicavam-se os protocolos terapêuticos propriamente ditos. Em um dos protocolos empregou-se creme de barbatimão (CQ), em outro creme de quitosana (CQ), sendo estas as formulações testes. No terceiro protocolo fez uso do creme de alantoína (controle positivo) e por ultimo o creme base (controle negativo I). Em outra lesão efetuou-se apenas antissepsia sem terapia tópica associada com solução de cloreto de sódio a 0,9% (controle negativo II). Os resultados apontaram que os CB e o CQ contribuíram para que o processo de cicatrização evoluísse satisfatoriamente. Embora não tenham ocorrido diferenças estatísticas no percentual de contração entre os dois tratamentos (CB e CQ), clinicamente, notouse que as feridas tratadas com CB apresentaram respostas clínicas superiores ao CQ. No terceiro capítulo efetuou-se comparativamente, por meio da avaliação clínica e microscópica, a ação dos CQ e CB nas feridas dos mesmos animais submetidas aos tratamentos do capítulo dois. Para as análises histológicas foram considerados os períodos pré-definidos para morfometria e as amostras foram avaliadas quanto à predominância de infiltrado polimorfo e mononuclear, presença de crosta-necrose, tecido de granulação, fibroplasia, angiogênese, colagenização e reepitelização cutânea. A partir dos resultados obtidos pode-se afirmar que as atividades implicadas ao barbatimão e a quitosana contribuíram de forma semelhante para que o processo de cicatrização evoluísse satisfatoriamente, visto que os dois tratamentos não diferiram significativamente para nenhum parâmetro considerado neste estudo. Sugere-se que os protocolos terapêuticos à base de barbatimão e quitosana proporcionaram redução da inflamação aguda, bem como promoveram ativação fibroblástica, desenvolvimento precoce de tecido conjuntivo, neovascularização e reepitelização tecidual, conferindo alternativas comprovadamente eficazes e economicamente viáveis em relação ao processo de cicatrização.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Receptores adrenérgicos são amplamente expressos em diferentes tecidos, incluindo na pele. Recentemente foi descoberto que bloqueadores dos receptores &#946;-adrenérgicos são capazes de modular o processo de reparo tecidual. O propranolol é um &#946;-bloqueador não seletivo largamente utilizado na prática clínica para o tratamento de doenças cardiovasculares, parecendo apresentar propriedades antioxidantes. O objetivo desse estudo foi avaliar a resposta de diferentes doses de propranolol durante a lesão isquêmica cutânea em roedores. Ratos Wistar foram tratados com propranolol nas concentrações de 3 e 6 mg/kg. O grupo controle recebeu apenas o veículo e o grupo controle positivo recebeu vitamina E (50 mg/kg/dia). A administração do propranolol iniciou-se no dia da lesão, sendo realizada diariamente até o sacrifício. Incisões bilaterais foram feitas no dorso de cada animal. O flap foi suturado e foram realizadas lesões excisionais totais entre as lesões incisionais. A contração das lesões foi avaliada e os cortes histológicos foram corados com hematoxilina e eosina e vermelho de picrosirius. Foram utilizadas também as seguintes técnicas: Dopplerfluxometria, análises bioquímicas, análise estereológica e expressão de PECAM-1. O grupo tratado com 3 mg de propranolol apresentou uma maior redução na área total da lesão quando comparado ao grupo controle. Da mesma forma, este grupo apresentou um aumento na densidade de vasos sanguíneos, uma maior expressão de PECAM-1 e aumento na perfusão sanguínea na pele isquêmica e no sítio da lesão quando comparado ao grupo controle. Não observamos efeito antioxidante do propranolol neste modelo. Em resumo, nós sugerimos que o propranolol quando administrado na dose de 3 mg/kg/dia foi capaz de modular a angiogênese e melhorar o fechamento da lesão em modelo de roedores<br>Adrenoceptors are highly expressed in a wide variety of tissues, including skin. Recently, it was discovered that &#946;-blockers agents are able to modulate the wound healing process. Propranolol is a nonselective &#946;1 and &#946;2-blocker widely used in clinical practice for treating diseases of cardiovascular system. Moreover, this drug has been shown to have antioxidant properties. The aim of this study was to evaluate the response of different propranolol doses during cutaneous ischemic wound in rodents. Wistar rats were treated with propranolol at concentrations of 3 and 6 mg/kg/day, control group received only vehicle and positive control group received vitamin E (50 mg/kg/day). Propranolol administration began on the day of injury, and was administered daily until euthanasia. Bilateral incisions were performed the dorsum of each animal. The flap was sutured and a full-thickness wound was made between the incisional lesions. Wound contraction was evaluated and sections were stained with H&E and Sirius red. Laser Doppler flowmetry, biochemical analysis, stereological analysis, and protein expression of PECAM-1 were also measured. Propranolol treated with 3 mg group showed a reduction in total wound area when compared to control group. Also, propranolol treated with 3 mg group showed an increased of density of blood vessels, highest PECAM-1 expression and highest blood perfusion in ischemic skin and in the wound bed when compared to control group. In summary, we suggest that propranolol administered at 3 mg/day was able to modulate angiogenesis and improved closure of the lesion in this rodent model

La peau et son vieillissement sont un enjeu de santé publique. Les modèles expérimentaux disponibles pour l'étude du vieillissement cutané restent perfectibles. Dans ce contexte, nos objectifs étaient simultanément d'utiliser les modèles de peaux reconstruites (PR) développés dans notre laboratoire afin i) de mieux comprendre les mécanismes du vieillissement cutané, ii) de démontrer l'efficacité et le mécanisme d'action du sélénium comme « anti âge » et enfin iii) de les faire évoluer en utilisant le support poreux ou auto-assemblé avec des fibroblastes du même donneur prélevés à des âges différents. Ainsi, le modèle de PR cultivé sur une longue période a montré une surexpression du microARN miR30-a par RT qPCR dans les PR « âgées » avec une altération de la fonction barrière mesurée par la perte insensible en eau et une perturbation de la différenciation terminale (baisse d'expression de la loricrine et de l'involucrine). Avec le même modèle in vitro, nos résultats démontrent que la supplementation en sélénium retarde la sénescence des kératinocytes souches. Cette efficacité passe non pas par un effet antioxydant comme attendu mais par l'activation de leur adhésion à la lame basale, qui participe à les conserver souche et donc à préserver le renouvellement épidermique. Enfin, nous avons eu la chance exceptionnelle de préparer des PR avec des fibroblastes provenant d'un donneur unique prélevé à 36 et 72 ans. Les résultats immunohistologiques montrent que l'âge induit une augmentation de l'expression de l'élastine et de la fibrilline ainsi que leur co-expression. L'augmentation de LTBP1 et aSMA suggère que cette augmentation inattendue est due à une dérégulation de la voie TGF-ß et une différenciation des fibroblastes en myofibroblastes. En conclusion l'utilisation de différents modèles de PR a permis d'explorer les mécanismes conduisant au vieillissement cutané et de démontrer l'efficacité du sélénium comme anti âge<br>Skin and its aging is a public health issue. In vitro skin models available for the study aging remain perfectible. In this context, our objectives were simultaneously to use skin equivalent (SE) developed in our laboratory i) to better understand mechanisms of skin aging, ii) to demonstrate the effectiveness of selenium as “anti-aging” and finally iii) to improve SE using the porous or scaffold free model with fibroblasts from the same donor at different ages. Thus, the model of SE mimicking senescence showed an overexpression of microRNA miR30-a by RT qPCR in old SE with an alteration of the barrier function measured by the transepidermal water loss and a deficiency of epidermal terminal differentiation (decreased expression of loricrin and involucrin). With the same SE model, our results demonstrate that selenium supplementation delays the senescence of keratinocytes stem cells. This effectiveness does not involve antioxidant effect as expected but the activation of their adhesion to the basement membrane, which participates in preserving stemness and epidermal renewal. Finally, we had the opportunity to prepare SE with fibroblasts from a single donor at 36 and 72 years old. The histological results show that age induces an increase in the expression of elastin and fibrillin as well as their co-expression. The increase of LTBP1 and aSMA suggests that this unexpected increase is due to deregulation of the TGF-ß pathway and fibroblasts differentiation into myofibroblasts. In conclusion, the use of different models of SE helps us to explore some mechanisms leading to skin aging and to demonstrate the efficacy of selenium as “anti-aging”

La connaissance des propriétés mécaniques de la peau humaine in vivo est d’une importance capitale dans de nombreux domaines (médical, cosmétique…). L’objectif de cette thèse est de développer de nouveaux outils pour permettre d’une part au clinicien de caractériser de manière objective les propriétés mécaniques de la peau, et d’autre part d’améliorer la compréhension générale du comportement de cet organe avec le vieillissement. Le premier chapitre est une revue bibliographique de la physiologie et des propriétés physiques de la peau ainsi que des différents moyens d’investigations actuels de ses propriétés. A partir de cette revue, deux axes de recherche sont définis, un axe de sollicitation tangentielle et un axe de sollicitation normale au tissu. Le second chapitre s’intéresse au premier axe de recherche, avec le développement d’une méthode d’indentation dynamique et d’une méthode d’indentation sans contact. Une baisse du module d’Young est trouvée avec l’âge. Le troisième chapitre s’intéresse à l’axe de sollicitation tangentielle, avec une méthode d’extension compression couplant mesures d’efforts et mesures des champs de déplacements de la zone sollicitée. Une approche inverse par un modèle Éléments Finis avec une loi de comportement orthotrope montre à partir des essais réalisés une baisse globale des propriétés mécaniques de la peau avec l’âge. Le quatrième et dernier chapitre relie les deux approches (normale et tangentielle) en comparant les résultats obtenus et tire les perspectives de ces travaux<br>The knowledge of the mechanical properties of human skin in vivo is essential for many domains (medical, clinical…). The aim of this thesis is to develop new devices for the clinician in order to perform objective assessment of the mechanical properties of human skin, and also to improve the understanding of the whole mechanical behaviour of this organ with ageing.The first chapter is a bibliography concerning the physiology and the physical properties of the skin and also an overview of the actual devices used for the assessment of these properties. Based on this review, two different ways of stress have been chosen, a normal stress axis and a tangential stress axis to the skin.The second chapter concerns the first way of stress, with the development of a dynamic indentation method and a non contact method. A decrease of the Young modulus is found with ageing.The third chapter concerns a tangential axis of stress, with an extension-compression test using force measurement combined to displacement field measurement of the stressed area. An inverse method using a Finite Element model with an orthotropic law shows that results obtained give a decrease of the mechanical properties of the skin with ageing.The fourth and last chapter links the two different way of stress used with a comparison of results obtained and gives some perspectives of this work

La peau est l’organe le plus grand du corps humain et représente ~10% de la masse corporelle. La bonne qualité de son état et de ses fonctionnalités est primordiale pour la santé d’un individu. La sécheresse cutanée constitue un phénomène commun dans différents dysfonctionnements physiopathologiques. Grâce à ses propriétés de protection de l’organisme vis-à-vis de son environnement, le stratum corneum (SC) est considéré comme le principal élément contrôlant l’hydratation. Ce travail de thèse, associant des développements techniques et méthodologiques, a conduit à la mise en évidence par microspectroscopie Raman confocale, des mécanismes moléculaires impliqués dans les phénomènes de sécheresse cutanée. Le lien moléculaire entre hydratation et stress mécanique du SC ex vivo est décrit de manière approfondie impliquant lipides et protéines tissulaires. Ces travaux ont également porté sur la caractérisation des modifications supramoléculaires responsables des déformations du SC sous stress mécanique. En parallèle, ce travail illustre l’intérêt des spectroscopies vibrationnelles comme outil d’évaluation des mécanismes d’action des produits hydratants.Le caractère non-invasif de la spectroscopie Raman a permis d’exploiter les fortes potentialités de cette technique en transposant in vivo l’utilisation des descripteurs spectraux obtenus ex vivo. Ainsi, nous avons développé une approche in vivo couplant la spectroscopie Raman et la méthode des moindres carrés partiels (PLS) pour la quantification indirecte de différents paramètres physico-chimiques et fonctionnels du SC y compris les lipides et l’eau conduisant à une caractérisation globale du statut physiopathologique du SC<br>The skin is the largest organ of the human body, accounting for ~10% of the body weight. The quality of its state and functionality is essential for the human health. Dry skin is a common phenomenon in various physiopathological dysfunctions. The uppermost layer of the skin, the stratum corneum assumes the first barrier between organism and environment, it is thus considered as the main element controlling skin hydration. This work, combining technical and methodological developments, led to highlight the molecular mechanisms involved in skin dryness phenomena by confocal Raman microspectroscopy. The molecular link between hydration and mechanical stress of SC ex vivo is described in detail involving lipids and proteins. This work has also focused on the characterization of supramolecular changes related to the deformations of the SC under mechanical stress. In parallel, this work illustrates the effectiveness of vibrational spectroscopy for evaluation of moisturizers mechanisms of action. The non-invasive nature of Raman spectroscopy allowed exploiting the high potential of this technique by transposing spectral descriptors obtained ex vivo to in vivo. Thus, we developed an in vivo approach coupling Raman spectroscopy and partial least squares method (PLS) for indirect quantification of different physico-chemical and functional parameters including the SC lipids and water leading to an overall characterization of the SC physiopathological status

Depuis plus d’une cinquantaine d’années, de formidables avancées ont été initiées dans le domaine de l’ingénierie tissulaire cutanée menant à la reconstruction in vitro de substituts de peau. La plupart sont des substituts dermiques destinés à être utilisés comme aide à la cicatrisation des plaies aigües et chroniques en complément des traitements de greffes conventionnels ainsi que pour l’augmentation des tissus mous. Bien qu’un nombre croissant de patients aient pu bénéficier de ces matrices dermiques, leur application clinique reste encore restreinte, en raison de leur coût élevé mais également à cause de résultats cicatriciels parfois peu satisfaisants. Par conséquent, il reste un défi de taille, celui de développer des substituts dermiques stimulant activement la cicatrisation, présentant un faible coût de production, sans propriétés antigéniques et possédant des propriétés mécaniques adaptées. Dans ce cadre, les hydrogels à base de fibrine constituent des candidats prometteurs, en particulier en raison du rôle central de cette protéine dans la cicatrisation. Le principal inconvénient est qu’à concentration physiologique, ces hydrogels sont faibles mécaniquement, ce qui les rend difficilement manipulables. L’objectif de cette thèse a été la mise au point ainsi que la caractérisation de différents hydrogels destinés à être utilisés comme substituts dermiques. Ces derniers présentent l’avantage d’associer les propriétés biologiques de la fibrine avec les propriétés mécaniques d’un polymère synthétique, le polyéthylène glycol dans une architecture de réseaux interpénétrés de polymères (RIP). Les résultats obtenus ont permis : - de confirmer les propriétés physico-chimiques des RIP développés initialement par nos collaborateurs de l’université de Cergy-Pontoise, - de valider en trois étapes (in vitro, ex vivo puis in vivo) la biocompatibilité de ces nouvelles matrices, destinées à être utilisées comme supports de culture 2D et pour l’augmentation des tissus mous, - d’élaborer et de caractériser des matrices macroporeuses, optimisées pour la culture 3D de fibroblastes de dermes humains<br>Over the past five decades, we assisted in extraordinary advances in the field of skin tissue engineering which led to the in vitro reconstruction of a wide range of skin substitutes. Most of them are dermal substitutes: Their clinical application ranges from treating acute and chronic wounds to soft tissue augmentation. Although increasing numbers of patients have been treated with dermal substitutes, their clinical application has been limited by their substantial cost and some poor healing outcomes. Hence, there is still a challenge to produce a dermal substitute which enhance sufficiently wound healing. To this end, the substitute should exhibit suitable properties for enabling the repair process. Other requirements such as excellent biocompatibility, minimal antigenicity, ease to handle and cost-effective production are also essential. In this context, fibrin hydrogels constitute promising candidates for skin tissue engineering since fibrin fibers form a physiological and provisional backbone during wound healing. However, the poor mechanical properties of fibrin-based hydrogels at physiological concentration are an obstacle to their use. In this study, our aim was to design and characterize mechanically reinforced fibrin-based hydrogels by combining the intrinsic properties of a fibrin network with the mechanical features of a polyethylene glycol network using an interpenetrating polymer network (IPN) architecture. They are intended to be used as dermal scaffolds. The results obtained in this thesis: - Confirmed the suitable physico-chemical properties of IPN, first developed by our partner of the University of Cergy-Pontoise. - Validated their biocompatibility using a three-step approach (in vitro, ex vivo and in vivo assays). - Led to the synthesis and characterization of a new type of fibrin-based macroporous matrices, optimized for 3D dermal fibroblast culture

Purpose: To highlight the histopathological characteristics of the skin in congenital clubfoot and correlate the clinical findings in clubfoot with the changes in the dermal layers. Materials and methods: One hundred skin specimens, from 77 infants (6 to 12 months), were studied between 2004 and 2008. Using the Pirani scoring system, the clinical severity was recorded. The mobility of the skin and the correctability of the medial ray were assessed clinically. A skin specimen (1cm x 1mm) was taken from the medial side of the foot at surgery following failed plaster treatment. The layers were studied under light microscopy. The thickness of the dermis and the histopathological features of clubfoot skin were compared with 10 normal skin specimens. Results: The dermis of clubfoot skin showed significant fibrosis with thick bundles of collagen fibres (P = .001) on Haematoxylin and Eosin staining (H&E). The dermal thickness ranged between 1.0mm and 5.2mm in clubfoot skin, compared with controls (0.64-1.28mm). Fibrosis extended into the subcutis in a septolobular fashion in 95% of the cases. Significant atrophy of eccrine glands was seen in 98% (P = .001). Hair follicles were absent in 78%. The elastic fibres of clubfoot skin, stained with Elastic van Gieson staining (EVG), showed hypertrophy in varying degrees in all skin specimens. They were fragmented, with loss of their parallel arrangement. There was no significant inflammatory reaction in the dermis. The Pirani score was significantly increased (mean 7.8). Discussion: Fibrosis and thickening of the dermis were the most significant histopathological features of the clubfoot skin. The elastic fibres were also abnormal. There was atrophy of the skin appendages due to the fibrosis. There was a strong correlation between the Pirani score and the severity of the deformity(P 0.016). The cases with poor outcome had a higher score than those with a satisfactory outcome.Lack of a significant inflammatory reaction suggests that neither the serial manipulations of the foot, nor the repeated plaster cast changes, were responsible for the dermal fibrosis, which is probably present from birth and contributes to the deformity.<br>Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.

No<br>Contradictions and misconceptions regarding the effect of lime on the decay of human remains have demonstrated the need for more research into the effect of different types of lime on cadaver decomposition. This study follows previous research by the authors who have investigated the effect of lime on the decomposition of human remains in burial environments. A further three pig carcasses (Sus scrofa), used as human body analogues, were observed and monitored for 78 days without lime, with hydrated lime (Ca(OH)2) and with quicklime (CaO) in the taphonomy laboratory at the University of Bradford. The results showed that in the early stages of decay, the unlimed and hydrated lime cadavers follow a similar pattern of changes. In contrast, the application of quicklime instigated an initial acceleration of decay. Microbial investigation demonstrated that the presence of lime does not eliminate all aerobic bacteria. The experiment also suggested that lime functions as a sink, buffering the carbon dioxide evolution. This study complements the field observations. It has implications for the investigation of time since death of limed remains. Knowledge of the effects of lime on decomposition processes is of interest to forensic pathologists, archaeologists, humanitarian organisations and those concerned with disposal of animal carcasses or human remains in mass disasters.