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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Protein instability associated with PLGA delivery systems and UV-induced protein oxidation /

Estey, Tia Brie. January 2006 (has links)
Thesis (Ph.D. in Pharmaceutical Sciences) -- University of Colorado, 2006. / Typescript. Includes bibliographical references (leaves 144-161). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;
42

Fotocatálise heterogênea em instrumental odontológico recoberto com nanopartículas TiO2 e Ag

Porto, Cecília Helena Soares [UNESP] 23 September 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-09-23Bitstream added on 2014-06-13T20:47:33Z : No. of bitstreams: 1 porto_chs_me_arafo.pdf: 448656 bytes, checksum: 96388ac863c85fd0bce5d9b342562359 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A nova fronteira científica - a nanotecnologia - permite a fabricação de produtos com características diferenciadas pela modificação das propriedades dos materiais no nível atômico, manipulando átomos e moléculas com aplicação no processo de esterilização de instrumentos odontológicos. O objetivo deste estudo foi realizar uma avaliação da ação autolimpante e esterilizante do recobrimento de instrumentos odontológicos com nanopartículas de dióxido de titânio (TiO2) e prata Ag desencadeada pelo processo de fotocatálise heterogênea por ação da luz ultravioleta e da luz branca. Testes bacteriológicos foram realizados com espátulas de manipulação de cimento odontológico contaminadas com 10 mcrl para cada microrganismo, Enterococcus faecalis e Pseudomona aeruginosa, e após expostas a luz branca e a luz ultravioleta. A Pseudomona aeruginosa foi inativada após exposição de 120 minutos à luz UV, indicando a ocorrência do processo de fotocatálise heterogênea no recobrimento com nanopartículas de TiO2 e Ag, e não foi inativada pela exposição à luz branca, com a ocorrência de crescimento bacteriano. O Enterococcus faecalis não foi inativado pela exposição à luz UV e à branca. Os testes realizados com Staphylococus aureus, Bacilo Subtilis e com Escherichia coli foram positivos para o crescimento das bactérias, independente do tempo de exposição à luz UV (15, 30 e 60 minutos). Os testes realizados com Micrococcus luteus foram negativos para o crescimento das bactérias independente do tempo de exposição à luz UV (15, 30 e 60 minutos). O processo de fotocatálise é uma tecnologia alternativa que envolve a geração de radicais hidroxilas altamente oxidantes, que podem reagir com grandes variedades de compostos orgânicos, constituindo uma tecnologia limpa e promissora. / This novel scientific development – nanotchenology – has contributed to the creation of products with unique features through the modification on the properties of the materials in relation to their atomic level by manipulating atoms and molecules to be used in the process of dental instruments sterilization. . The objective of this study is to evaluate the self-cleaning action of TiO2 and Ag nanoparticles coating by the photocatalysis process under UV and visible light irradiation. Microbiologic tests were done using dental cement spatulas contaminated with 10 mcrl Pseudomonas aeruginosa and Enterococcus faecalis and exposed to UV and visible light irradiation for 120 min, respectively. Pseudomonas aeruginosa proved inactive under 120 min UV light irradiation time, thus confirming the photocatalytic activity of TiO2 and Ag, which was not confirmed under visible light irradiation. Enterococcus faecalis did not confirm the photocatalytic activity of TiO2 and Ag under UV and visible light irradiation. Tests done with Stafilococcus aureus, Bacillus subtilis and Escherichia coli did not confirm the photocatalytic activity regardless the UV light irradiation time (15, 30 and 60 minutes); however, tests done with Micrococcus luteus confirmed the photocatalytic activity regardless the light irradiation time (15, 30 and 60 minutes). The photocatalysis process is an alternative technology which generates highly oxidizing hydroxyl radicals that react with a wide variety of organic compounds, thus developing a clean and promising technology.
43

Estudo clinicopatologico e imunoistoquimico de prurigo actinico de labio / Clinicopathological and imunohistochemical study af actinic prurigo of lip

Toral Rizo, Victor Hugo, 1977- 14 August 2018 (has links)
Orientador: Oslei Paes de Almeida / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-14T03:19:43Z (GMT). No. of bitstreams: 1 ToralRizo_VictorHugo_M.pdf: 5977803 bytes, checksum: e23d73a627c912289b1e0630bf6ccfff (MD5) Previous issue date: 2009 / Resumo: O prurigo actínico (PA) é uma fotodermatose familiar específica que afeta principalmente os mestiços, fruto da miscigenação entre índios e europeus, que habitam vários países da América do Norte, Central e do Sul. Pode manifestar-se em qualquer idade, no entanto a doença inicia-se freqüentemente na infância, entre os seis e oito anos de idade. É mais freqüente em mulheres, e atinge principalmente pessoas que vivem em regiões acima de mil metros de altitude. O PA afeta principalmente áreas da pele expostas ao sol. Clinicamente se apresenta de forma polimórfica. O objetivo deste estudo foi analisar as características clínicas, histopatológicas e a expressão de marcadores imunoistoquímicos de 43 casos de PA de lábio. Dezesseis casos envolviam pacientes do gênero masculino e 27 casos (62,80%) do gênero feminino, com idade média de 28,6 anos. Todos os casos envolviam o lábio inferior e outras áreas da face e do corpo, e 17 casos (39,54%) somente apresentavam manifestação em lábio inferior. As principais alterações clínicas eram: crosta, pápulas eritematosas, hiperpigmentação, descamação, placas, úlceras e edema. Microscopicamente observou-se no epitélio superficial principalmente hiperqueratose, ulceração, vacuolização das células da camada basal e exocitose. No conjuntivo subjacente observou-se quadro inflamatório crônico, em muitos casos predominando a presença de folículos linfóides em diversos graus de organização. Nenhum dos casos apresento elastose solar. Os marcadores imunoistoquímicos mostraram que os folículos linfóides apresentavam organização semelhante ao normal. Syndecan-1 marcou as células da camada espinhosa de forma homogênea, mas estava ausente nas células basais e suprabasais. D2-40 com marcação positiva e forte nas células dendríticas do centro folicular e camada basal do epitélio superficial. Mastócitos, eosinófilos e macrófagos estavam distribuídos entre as células linfoplasmocitárias. / Abstract: Actinic prurigo (AP) is a specific familial photodermatosis that affects mainly mestizos, who live in many parts of North, Central and South America. AP can be clinically evident at any age, but it starts in infancy, between 6 and 8 years of age. It is more frequent in women. AP affects mainly persons living in regions above one thousand meters sea level. The disease affects mainly sun exposed skin, andclinically it is polymorphic. The objective of this study was to evaluate the clinical, histological and immunohistochemistry characteristics of 43 cases of AP of the lower lip. Sixteen cases were in males and 24 females (62.8%), with mean age of 28.6%. All cases involved the lower lip and other skin sites, but in 17 cases the lesions occurred only in the lower lip (39.54%). Hyperpigmentation, descamation, plaques, ulcers and edema were the main clinical alterations in our series. Microscopically on the superficial epithelial it was found mainly hyperqueratosis, ulceration, vacuolization of the basal and supra basal layer cells and exocytosis. In the subjacent connective tissue predominated a chronic inflammatory process, in many cases rich in lymphoid follicles in various degrees of organization. In none of the cases it was observed elastosis in the connective tissue. Immunohistochemistry markers confirmed that the follicles showed an organization similar to normal follicles. Syndecan-1 was expressed homogenously in the spinous layers of the superficial epithelium, but it was negative in the basal and suprabasal layers. D2-40 was positive in the dendritic cells of the follicular centers and basal cells of the superficial epithelium. Mast cell, eosinophils, and macrophages were found among the plasmatic cells. / Mestrado / Patologia / Mestre em Estomatopatologia
44

Ultrastructural characterization of ultraviolet induced corneal disease : an animal model

Schultes, Klaus January 1994 (has links)
The majority of ancient people worshipped the sun and viewed it as a health - bringing deity. During the eighteenth and nineteenth century therapeutic benefits of sunlight exposure were beginning to be understood and by the end of the nineteenth century the importance of ultraviolet radiation was being realized. Danish physician Niels Finsen, whom many regard as the father of ultraviolet phototherapy, also stressed that it was ultraviolet radiation in the solar spectrum which cause sunburn. We now recognize that the small portion of ultraviolet radiation which reaches the earth's surface is not necessarily therapeutic, but in fact could be harmful to humans. There are numerous accounts of the harmful effects of UV radiation to the skin and the eye as a whole. These effects may be caused by either acute or chronic exposure to UV radiation. For example, some acute effects of UV-B radiation include conjunctivitis and photokeratitis. "Snow blindness" and "arc welders eye" are further examples of acute ultraviolet damage specifically to the surface of the cornea. On the other hand, chronic exposure to ultraviolet radiation is thought to be responsible for pterygia, climatic droplet keratopathy Hill and Maske (1989), cancers of the external eye, cataracts and various types of retinal diseases. The present study is an extension of ongoing studies on ultraviolet radiation damage to the cornea in the Department of Ophthalmology, University of Cape Town and Groote Schuur Hospital. Their specific interest lies in the causes and treatment of climatic droplet keratopathy. The aims of the present study are: 1) Establish a possible role of ultraviolet B radiation in human corneal diseases such as climatic droplet keratopathy and pterygium using the rabbit as an animal model. 2) Determine by means of SEM the initial effects and subsequent recovery of the epithelium after a 3-hour dose of ultraviolet B radiation. We refer to this study as "acute" response to ultraviolet B radiation. 3) To try and confirm the effects observed by SEM with ultrastructural studies using TEM. 4) In addition, we are also looking at the possible effects after exposing rabbit cornea to a daily dose of low level ultraviolet B radiation, over a long period of time. We refer to this as chronic exposure to ultraviolet B radiation. It is hoped that by exposing rabbits to ultraviolet light, principally ultraviolet B radiation, diseases similar to those found in humans could be simulated and disease progression studied. People are generally exposed to substantial amounts of UV radiation for a very long time. Since people generally live longer they will be exposed to an ever-increasing amount of solar UV radiation and subsequently, there is an increasing risk of developing corneal diseases. The possible threat to the ozone is also a real possibility and could lead to increased levels of ultraviolet radiation reaching the earth's surface. This will require a greater understanding of the very nature of corneal damage due to acute and chronic exposure. This study focusses mainly on the acute response to UV-B radiation since most studies have investigated effects of prolonged exposure to UV light. Accordingly, much less is known about acute exposure. Many people suffering from acute UV B radiation effects probably never visit the ophthalmologist or wait for a couple of days. This could also contribute to the fact that effects of short-term damage is not well documented.
45

DNA degradation and repair in Escherichia coli following UV irradiation/

Fong, Kenneth Shui-yuen January 1977 (has links)
This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).
46

Efeitos da radiação ultravioleta b na expressão imunoistoquímica das metaloproteinases –2 e –9 em nevos melanocíticos / Acute effects of ultraviolet radiation B in immunohistochemical expression of matrix metalloproteinases –2 and –9 in melanocytic nevi

Bakos, Renato Marchiori January 2005 (has links)
Introdução: a incidência dos melanomas permanece em ascensão em diversos países. Os nevos melanocíticos podem ser seus precursores ou marcadores de risco. A radiação ultravioleta é o principal fator de risco ambiental para o seu desenvolvimento. Estudos com nevos irradiados mostram que a radiação ultravioleta B (UVB) pode causar alterações morfológicas e bioquímicas semelhantes às de um melanoma in situ. As metaloproteinases da matriz (MMP) são enzimas proteolíticas e, particularmente, as MMP-2 e –9 (gelatinases A e B) parecem estar associadas à invasão tumoral, à formação de metástases e de neoangiogênese em melanomas. O objetivo do presente estudo é avaliar os efeitos da UVB nas expressões imunoistoquímicas de MMP-2 e –9 nas diferentes linhagens celulares de nevos melanocíticos. Métodos: quarenta e dois nevos melanocíticos tiveram suas metades irradiadas com dose de 2 DEM (dose eritematosa mínima) de UVB e foram excisados uma semana após. As expressões imunoistoquímicas das MMP-2 e -9 foram comparadas, quanto à sua intensidade, por três avaliadores diferentes entre os lados irradiados e não irradiados em queratinócitos, melanócitos de epiderme e derme superior, células endoteliais e fibroblastos. Os dados foram analisados pelo teste t pareado para as diferenças de expressão e pelo ICC para avaliação da homogeneidade entre as respostas dos observadores. Resultados: com relação à expressão imunoistoquímica de MMP-2, todas as linhagens celulares mostraram aumento no lado irradiado, especialmente os melanócitos epidérmicos. Quanto à MMP-9, somente nos queratinócitos, não se observou aumento de expressão do lado irradiado, ficando essa evidente nas demais linhagens celulares avaliadas. Conclusões: A UVB na dose de 2 DEM aumenta a expressão imunoistoquímica das MMP-2 e –9 em quase todas as linhagens celulares dos nevos melanocíticos avaliados até uma semana após a irradiação, com exceção feita queratinócitos, com a MMP-9. / Background: the incidence of melanoma continues to increase in several countries. Melanocytic nevi may represent precursors or risk indicators of cutaneous melanoma. Ultraviolet radiation is the main environmental risk factor in their development. Studies with irradiated nevi show that ultraviolet B (UVB) radiation can cause morphological and biological alterations similar to those of a melanoma in situ. Matrix metalloproteinases (MMP) are proteolytic enzymes, and MMP-2 and -9 (gelatinase A and B) in particular, appear to be involved with tumour invasion, the formation of metastases and neoangiogenesis in melanomas. This study aims to evaluate the effects of UVB radiation on the immunohistochemical expression of MMP–2 and –9 in different cell lines from melanocytic nevi. Methods: one half of each of the forty-two melanocytic nevi used in the study was irradiated with 2 MEDs (Minimal Erythema Dosis) of UVB radiation and excised one week later. Three different observers were given the task of comparing the intensity of the immunohistochemical expression of the MMP –2 and –9 on the irradiated and nonirradiated sides of keratinocytes, melanocytes from the epidermis and upper dermis, endothelial cells and fibroblasts. The collected data were analysed using the paired t test for differences in expression and ICC in order to assess the homogeneity of the evaluations made by the observers. Results: in relation to the expression of MMP–2, all the cell lines showed an increase on the irradiated sides, especially the epidermal melanocytes. Regarding MMP-9, while no significant increase in its expression in keratinocytes was noted on the irradiated side, significant increases were observed in the remaining lines. Conclusions: UVB radiation at 2 MEDs increases the immunohistochemical expression of MMP –2 and –9 in almost all evaluated cell lines up to one week after irradiation, with the exception of MMP-9 in keratinocytes.
47

Efeitos da radiação ultravioleta b na expressão imunoistoquímica das metaloproteinases –2 e –9 em nevos melanocíticos / Acute effects of ultraviolet radiation B in immunohistochemical expression of matrix metalloproteinases –2 and –9 in melanocytic nevi

Bakos, Renato Marchiori January 2005 (has links)
Introdução: a incidência dos melanomas permanece em ascensão em diversos países. Os nevos melanocíticos podem ser seus precursores ou marcadores de risco. A radiação ultravioleta é o principal fator de risco ambiental para o seu desenvolvimento. Estudos com nevos irradiados mostram que a radiação ultravioleta B (UVB) pode causar alterações morfológicas e bioquímicas semelhantes às de um melanoma in situ. As metaloproteinases da matriz (MMP) são enzimas proteolíticas e, particularmente, as MMP-2 e –9 (gelatinases A e B) parecem estar associadas à invasão tumoral, à formação de metástases e de neoangiogênese em melanomas. O objetivo do presente estudo é avaliar os efeitos da UVB nas expressões imunoistoquímicas de MMP-2 e –9 nas diferentes linhagens celulares de nevos melanocíticos. Métodos: quarenta e dois nevos melanocíticos tiveram suas metades irradiadas com dose de 2 DEM (dose eritematosa mínima) de UVB e foram excisados uma semana após. As expressões imunoistoquímicas das MMP-2 e -9 foram comparadas, quanto à sua intensidade, por três avaliadores diferentes entre os lados irradiados e não irradiados em queratinócitos, melanócitos de epiderme e derme superior, células endoteliais e fibroblastos. Os dados foram analisados pelo teste t pareado para as diferenças de expressão e pelo ICC para avaliação da homogeneidade entre as respostas dos observadores. Resultados: com relação à expressão imunoistoquímica de MMP-2, todas as linhagens celulares mostraram aumento no lado irradiado, especialmente os melanócitos epidérmicos. Quanto à MMP-9, somente nos queratinócitos, não se observou aumento de expressão do lado irradiado, ficando essa evidente nas demais linhagens celulares avaliadas. Conclusões: A UVB na dose de 2 DEM aumenta a expressão imunoistoquímica das MMP-2 e –9 em quase todas as linhagens celulares dos nevos melanocíticos avaliados até uma semana após a irradiação, com exceção feita queratinócitos, com a MMP-9. / Background: the incidence of melanoma continues to increase in several countries. Melanocytic nevi may represent precursors or risk indicators of cutaneous melanoma. Ultraviolet radiation is the main environmental risk factor in their development. Studies with irradiated nevi show that ultraviolet B (UVB) radiation can cause morphological and biological alterations similar to those of a melanoma in situ. Matrix metalloproteinases (MMP) are proteolytic enzymes, and MMP-2 and -9 (gelatinase A and B) in particular, appear to be involved with tumour invasion, the formation of metastases and neoangiogenesis in melanomas. This study aims to evaluate the effects of UVB radiation on the immunohistochemical expression of MMP–2 and –9 in different cell lines from melanocytic nevi. Methods: one half of each of the forty-two melanocytic nevi used in the study was irradiated with 2 MEDs (Minimal Erythema Dosis) of UVB radiation and excised one week later. Three different observers were given the task of comparing the intensity of the immunohistochemical expression of the MMP –2 and –9 on the irradiated and nonirradiated sides of keratinocytes, melanocytes from the epidermis and upper dermis, endothelial cells and fibroblasts. The collected data were analysed using the paired t test for differences in expression and ICC in order to assess the homogeneity of the evaluations made by the observers. Results: in relation to the expression of MMP–2, all the cell lines showed an increase on the irradiated sides, especially the epidermal melanocytes. Regarding MMP-9, while no significant increase in its expression in keratinocytes was noted on the irradiated side, significant increases were observed in the remaining lines. Conclusions: UVB radiation at 2 MEDs increases the immunohistochemical expression of MMP –2 and –9 in almost all evaluated cell lines up to one week after irradiation, with the exception of MMP-9 in keratinocytes.
48

Efeitos da radiação ultravioleta b na expressão imunoistoquímica das metaloproteinases –2 e –9 em nevos melanocíticos / Acute effects of ultraviolet radiation B in immunohistochemical expression of matrix metalloproteinases –2 and –9 in melanocytic nevi

Bakos, Renato Marchiori January 2005 (has links)
Introdução: a incidência dos melanomas permanece em ascensão em diversos países. Os nevos melanocíticos podem ser seus precursores ou marcadores de risco. A radiação ultravioleta é o principal fator de risco ambiental para o seu desenvolvimento. Estudos com nevos irradiados mostram que a radiação ultravioleta B (UVB) pode causar alterações morfológicas e bioquímicas semelhantes às de um melanoma in situ. As metaloproteinases da matriz (MMP) são enzimas proteolíticas e, particularmente, as MMP-2 e –9 (gelatinases A e B) parecem estar associadas à invasão tumoral, à formação de metástases e de neoangiogênese em melanomas. O objetivo do presente estudo é avaliar os efeitos da UVB nas expressões imunoistoquímicas de MMP-2 e –9 nas diferentes linhagens celulares de nevos melanocíticos. Métodos: quarenta e dois nevos melanocíticos tiveram suas metades irradiadas com dose de 2 DEM (dose eritematosa mínima) de UVB e foram excisados uma semana após. As expressões imunoistoquímicas das MMP-2 e -9 foram comparadas, quanto à sua intensidade, por três avaliadores diferentes entre os lados irradiados e não irradiados em queratinócitos, melanócitos de epiderme e derme superior, células endoteliais e fibroblastos. Os dados foram analisados pelo teste t pareado para as diferenças de expressão e pelo ICC para avaliação da homogeneidade entre as respostas dos observadores. Resultados: com relação à expressão imunoistoquímica de MMP-2, todas as linhagens celulares mostraram aumento no lado irradiado, especialmente os melanócitos epidérmicos. Quanto à MMP-9, somente nos queratinócitos, não se observou aumento de expressão do lado irradiado, ficando essa evidente nas demais linhagens celulares avaliadas. Conclusões: A UVB na dose de 2 DEM aumenta a expressão imunoistoquímica das MMP-2 e –9 em quase todas as linhagens celulares dos nevos melanocíticos avaliados até uma semana após a irradiação, com exceção feita queratinócitos, com a MMP-9. / Background: the incidence of melanoma continues to increase in several countries. Melanocytic nevi may represent precursors or risk indicators of cutaneous melanoma. Ultraviolet radiation is the main environmental risk factor in their development. Studies with irradiated nevi show that ultraviolet B (UVB) radiation can cause morphological and biological alterations similar to those of a melanoma in situ. Matrix metalloproteinases (MMP) are proteolytic enzymes, and MMP-2 and -9 (gelatinase A and B) in particular, appear to be involved with tumour invasion, the formation of metastases and neoangiogenesis in melanomas. This study aims to evaluate the effects of UVB radiation on the immunohistochemical expression of MMP–2 and –9 in different cell lines from melanocytic nevi. Methods: one half of each of the forty-two melanocytic nevi used in the study was irradiated with 2 MEDs (Minimal Erythema Dosis) of UVB radiation and excised one week later. Three different observers were given the task of comparing the intensity of the immunohistochemical expression of the MMP –2 and –9 on the irradiated and nonirradiated sides of keratinocytes, melanocytes from the epidermis and upper dermis, endothelial cells and fibroblasts. The collected data were analysed using the paired t test for differences in expression and ICC in order to assess the homogeneity of the evaluations made by the observers. Results: in relation to the expression of MMP–2, all the cell lines showed an increase on the irradiated sides, especially the epidermal melanocytes. Regarding MMP-9, while no significant increase in its expression in keratinocytes was noted on the irradiated side, significant increases were observed in the remaining lines. Conclusions: UVB radiation at 2 MEDs increases the immunohistochemical expression of MMP –2 and –9 in almost all evaluated cell lines up to one week after irradiation, with the exception of MMP-9 in keratinocytes.
49

Estudo da fotoestabilidade de filtros solares comerciais quando expostos a radiação ultra-violeta artificial e lâmpadas fluorescentes comerciais / Phostostability assessment of commercial sunscreens upon artificial ultraviolet and fluorescent lamp exposures

Romanhole, Rodrigo Collina, 1979- 10 July 2014 (has links)
Orientadores: Priscila Gava Mazzola, Patrícia Moriel / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T05:30:45Z (GMT). No. of bitstreams: 1 Romanhole_RodrigoCollina_M.pdf: 2407995 bytes, checksum: a3fd76e8329a74f761c010fad33c4377 (MD5) Previous issue date: 2014 / Resumo: Filtros solares são moléculas com capacidade de absorver e/ou refletir a radiação UVA e UVB, evitando assim que esta radiação alcance a epiderme ou até mesmo a derme, porém alguns filtros podem apresentar instabilidade quando absorvem a radiação, com consequente perda desta função. A fotoinstabilidade após a exposição à radiação UV é bem conhecida e descrita, porém não existem muitos dados relacionando a estabilidade destes filtros após a irradiação de luz fluorescente emitida pelas lâmpadas comerciais presentes em lares e escritórios. O presente estudo propõe avaliar a fotoestabilidade de produtos comerciais com FPS 30, após irradiação UV e também após a irradiação fluorescente, correlacionando o comportamento de cada produto frente aos diferentes tipos de radiação. A metodologia aplicada é in vitro, sendo que os produtos testados foram aplicados em duas diferentes placas de polimetilmetacrilato Polimetil metacrilato (PMMA) e irradiados por um simulador solar com filtros específicos para UVA/B e por uma fonte de luz fluorescente comercial. De acordo com os resultados obtidos, foi observado que a placa de PMMA utilizada pode influenciar nos resultados e todas as amostras testadas apresentaram um comportamento fotoestável quando expostos à radiação ultravioleta ou fluorescente, ou seja, não apresentaram redução na sua capacidade de absorção da radiação UVA/B mesmo após doses de radiação bem elevadas. Estes resultados demonstram que as amostras testadas apresentaram um comportamento bastante estável em diversas situações em que a população está exposta no dia a dia / Abstract: Sunscreens are molecules with ability to absorb and/or reflect the UVA and UVB radiation, thereby preventing radiation that reaches the epidermis or dermis even though some filters can be unstable when they absorb radiation, with consequent loss of its function. The photostability after exposure to UV radiation is well known and described, but there are not many data correlating the stability of these filters after fluorescent light irradiation, emitted by commercial lamps present in homes and offices. This study proposes to assess the photostability of commercial products SPF 30 after artificial UV irradiation and also after the fluorescent radiation, correlating the behavior of each product against different types of radiation. The methodology applied was in vitro, and the products tested were applied on two different plates of polymethyl methacrylate (PMMA) and irradiated by a solar simulator with specific filters for UVA/B and a fluorescent light source commercial. According to the results, the plate can play an important role in the photostability data and all samples tested presented a similar photostable behavior when exposed to UV or fluorescent light, or showed no reduction in its capacity for absorption of UVA/B even after higher doses of radiation. These results demonstrate that the samples tested presented a very stable behavior in various situations in which the population is exposed on a daily basis / Mestrado / Ciencias Biomedicas / Mestre em Ciências Médicas
50

Učestalost, vrsta i lokalizacija premalignih i malignih lezija kože kod bolesnika nakon transplantacije bubrega / Frequency, type and localization of premalignant and malignant skin lesions in renal transplant recipients

Roš Tatjana 27 September 2016 (has links)
<p>Osobe kojima su transplantirani organi imaju povećan rizik pojave malignih oboljenja, među kojima dominiraju maligni tumori kože. Smatra se da je osnovni razlog primena imunosupresivne terapije, ali jo&scaron; nije sasvim jasan mehanizam i nivo dejstva različitih imunosupresiva. Važan uticaj na nastanak većine malignih tumora kože ima ultraljubičasto (UV) zračenje koje izaziva pojačano starenje kože u vidu histolo&scaron;ki prepoznatljivog fotoo&scaron;tećenja, sa odlikama razvoja elastoze i limfocitne infiltracije. U na&scaron;oj zemlji do sada nisu sprovođena istraživanja rizika pojave maligniteta kože kod transplantiranih pacijenata, ne postoje podaci o njihovoj incidenci, uticaju imunosupresivne terapije i drugim potencijalnim faktorima rizika. U dostupnoj literaturi nema objavljenih radova iz oblasti analize histolo&scaron;kog fotoo&scaron;tećenja kože kod osoba na imunosupresivnoj terapiji. Ciljevi ove studije preseka bili su utvrđivanje učestalosti, vrste i lokalizacije premalignih i malignih lezija kože kod pacijenata nakon transplantacije bubrega, povezanosti njihove pojave sa dužinom, vrstom i režimom primene imunosupresivne terapije i sa histolo&scaron;ki verifikovanim fotoo&scaron;tećenjem perilezionalne kože. U studiju je uključeno 66 pacijenata kojima je transplantiran bubreg (primaoci organskog transplantata &ndash; POT). Relevantni podaci su prikupljeni putem upitnika i iz medicinske dokumentacije, kliničko-dermoskopskim pregledom kože uočene suspektne lezije su bioptirane u cilju postavljanja dijagnoze i utvrđivanja histolo&scaron;kih parametara fotoo&scaron;tećenja, a u studiju su uključeni i maligni tumori kože POT ispitanika uklonjeni u periodu od prethodnih 5 godina ali nakon transplantacije. Radi komparacije prisutnih faktora rizika i stepena fotoo&scaron;tećenja kože sa op&scaron;tom populacijom formirana je kontrolna grupa (KG) ispitanika kojima je prethodno bioptirana koža, bez oboljenja bubrega i bez imunosupresije, slična po polu i životnoj dobi sa onim POT ispitanicima kojima je urađena biopsija. Za svaku leziju iz POT grupe obezbeđene su po 2 lezije iz KG, tako da je pojedinim ispitanicima POT grupe analizirano vi&scaron;e lezija, dok je u KG 1 ispitanik &ndash; 1 lezija. Osnovno oboljenje bubrega do započinjanja dijalize kod ispitanika POT grupe prosečno je trajalo 7,67 godina, u strukturi oboljenja bubrega dominirao je hronični glomerulonefritis sa 31,8%, a ispitanici su na dijalizi bili prosečno 4,54 godine. Prosečna životna dob ispitanika u momentu transplantacije iznosila je 42,5 godina, 60,6% imalo je isključivo kadaveričnu transplantaciju, a prosečno trajanje jatrogene imunosupresije iznosilo je 4,89 god. U POT grupi bioptirane su 33 lezije, među kojima su od značaja za studiju bile 2 (6,1%) aktinične keratoze (AK), 3 (9,1%) displastična nevusa (DN), 1 (3,0%) melanom (MM), 3 (9,1%) skvamocelularna karcinoma (SCK) i 6 (18,2%) bazocelularnih karcinoma (BCK). U POT grupi učestalost MM bila je 1,5%, učestalost SCK 4,5%, učestalost BCK 9,1%, dok je utvrđeni relativan rizik pojave MM u POT populaciji 227 puta veći, BCK 316 puta veći, a SCK 805 puta veći nego u op&scaron;toj populaciji. Relativan rizik nastanka AK i DN nije određen zbog izostanka zvanične registracije u op&scaron;toj populaciji. POT grupa i KG nisu se statistički značajno razlikovale po Ficpatrikovom fototipu kože, profesionalnoj izloženosti UV zračenju, upotrebi solarijuma, broju solarnih opekotina, ličnoj anamnezi malignih tumora kože i konzumiranju cigareta. Pripadnici KG su se značajno vi&scaron;e rekreativno izlagali UV zračenju, če&scaron;će koristili sredstva za za&scaron;titu od sunčevog zračenja, če&scaron;će imali bliske srodnike sa malignim tumorima kože, če&scaron;će konzumirali alkohol, značajno veći broj ispitanika KG imao je pregled kompletne kože i informaciju o merama prevencije od strane lekara, dok 50% ispitanika POT grupe nije znalo da su pod povećanim rizikom pojave maligniteta kože. U stepenu elastoze među grupama nije postojala statistički značajna razlika, dok je limfocitna infiltracija bila marginalno izrazitija u POT grupi bez obzira na vrstu lezije. U POT grupi utvrđena je statistički značajna povezanost prisustva malignog tumora sa većim stepenom perilezionalne limfocitne infiltracije i elastoze. U KG utvrđena je statistički značajna povezanost prisustva malignog tumora sa većim stepenom limfocitne infiltracije, dok nije bilo statistički značajne razlike u stepenu perilezionalne elastoze. U studiji je utvrđeno da osobe nakon transplantacije bubrega imaju statistički značajno veći rizik nastanka BCK, SCK i MM kože u odnosu na op&scaron;tu populaciju, sa najče&scaron;ćom lokalizacijom ovih tumora u predelu glave. Dužina primene imunosupresivne terapije uop&scaron;teno nije statistički značajno uticala na pojavu premalignih i malignih tumora kože, ali je kumulativna doza pojedinih imunosupresiva poput ciklosporina i azatioprina imala statistički značajan uticaj na pojavu premalignih i malignih lezija kože. Dužina imunosupresije je statistički značajno uticala na stepen elastoze, ali je imala marginalan uticaj na stepen perilezionalne limfocitne infiltracije.</p> / <p>Organ transplant recipients are at an increased risk of developing malignancies, with the predominance of malignant skin tumors. The main cause is considered to be the administration of immunosuppressive therapy, but the mechanism and effect levels of different immunosuppressive agents are still not completely clear. Ultraviolet (UV) rays also influence the development of malignant skin tumors, causing increased skin aging with histologically recognisable photo damage, with its hallmark being development of elastosis and lymphocytic infiltration. No research on the topic of risks of malignant skin tumors in transplant patients has been done in our country, there is no data on their incidence, or on the effects of immunosuppressive agents and other potential risk factors. There are also no published studies in the field of hystological photo damage analysis in patients on immunosuppressive therapy. The aims of this study were to establish the rates of occurance, types and localisation of premalignant and malignant skin lesions in kidney transplant recipients (KTR) and to associate their advent with the length, type and regimen of immunosuppressive therapy. A total of 66 KTR patients were enrolled in the study. Relevant information was gathered through a specially constructed questionnaire and from the medical records, followed by combined clinical and dermoscopic skin examination to detect suspicious lesions which were biopsied in order to determine the histopathologic diagnosis of the lesion and perilesional degree of photo damage. The study also encompassed malignant skin tumors of KTR patients that have been removed in the last 5 years, but after the transplantation. For the sake of comparison of the risk factors and the levels of photo damage with the general population, an age and sex - matched control group (CG) of patients with previous skin biopsy but without kidney disease and immunosuppression was formed. For each lesion from KTR group, 2 lesions from CG were provided, meaning that some KTR patients had several lesions analysed, whereas in the CG only 1 lesion per patient was analyzed. The average duration of underlying kidney diseases in KTR was 7,67 years, the most frequent being chronic glomerulonephritis (31,8%), and an average duration of dialysis was 4,54 years. The mean age at transplantation was 42,5 years, with 60,6% of the KTR having exclusively cadaveric graft. The mean duration of the iatrogenic immunosuppression was 4,89 years. In the KTR group a total of 33 lesions were biopsied, 2 of which were actinic keratoses (AK) (6,1%), 3 were dysplastic nevi (DN) (9,1%), 1 melanoma (MM) (3,0%), 3 squamous cell carcinomas (SCC) (9,1%) and 6 basal cell carcinomas (BCC) (18,2%). The estimated frequency of MM was 1,5%, SCC 4,5%, BCC 9,1%, and the estimated relative risk of MM in KTR being 227, BCC 316, and SCC 805 times higher compared to the general population. The relative risk of AK and DN development could not have been estimated as there are no official records in the general population. The KTR and CG were not significantly different judging by the Fitzpatrick skin phototype, occupational UV exposure, sunbed usage, personal history of skin cancers, or smoking. The controls were recreationally more exposed to UV rays, used sun protective measures more frequently, had more relatives with skin cancers and consumed alcohol more frequently. A significantly greater number of controls had had complete skin examination and protective measures counceling by the doctor, while 50% of KTR patients did not even know that they were at an increased risk of malignant skin tumor development. There was no significant difference in elastosis levels among the groups, whereas the lymphocitic infiltration was only marginally greater in the KTR group. A significant association between the level of perilesional photodamage and developement of malignant tumors was estimated for the KTR group, whereas in the CG only the perilesional lymphocitic infiltration was strongly associated to malignant lesions. The study results suggest that KTR patients have a significantly higher risk of BCC, SCC and MM development in comparison with the general population, the most common localisation being in the head region. The duration of the immunosuppressive therapy had no significant effect on the premalignant and malignant tumors development, whereas the cummulative dose of certain immunosuppressives (such as cyclosporine and azathioprine) affected the development notably. The duration of immunosuppression statistically influenced the elastosis levels, but had only a marginal influence on the perilesional lymphocitic infiltration levels.</p>

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