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Quercetin inhibits UV irradiation-induced inflammatory cytokine production in primary human keratinocytes by suppressing NF-kappa B pathway

VICENTINI, Fabiana T. M. C.; HE, Tianyuan; SHAO, Yuan; FONSECA, Maria J. V.; VERRI JR., Waldiceu A.; FISHER, Gary J.; XU, Yiru
Fonte: ELSEVIER IRELAND LTD Publicador: ELSEVIER IRELAND LTD
Tipo: Artigo de Revista Científica
ENG
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45.75%
Background: Topical flavonoids, such as quercetin, have been shown to reduce ultraviolet (UV) irradiation-mediated skin damage. However, the mechanisms and signaling pathways involved in this protective effect are not clear. UV irradiation leads to activation of two major signaling pathways, namely nuclear factor kappa B (NF-kappa B) and activator protein-1 (AP-1) pathways. Activation of NF-kappa B pathway by UV irradiation stimulates inflammatory cytokine expression, whereas activation of AP-1 pathway by UV irradiation promotes matrix metalloproteinase (MMP) production. Both pathways contribute to UV irradiation-induced skin damage, such as photoaging and skin tumor formation. Objective: To elucidate the underlying mechanism, we examined the effect of quercetin on UV irradiation induced activation of NF-kappa B and AP-1 pathways. Methods: Primary human keratinocytes, the major skin cell type subjected to physiological solar UV irradiation, were used to study the effects of quercetin on UV irradiation-induced signal transduction pathways. Results: Quercetin decreased UV irradiation-induced NF-kappa B DNA-binding by 80%. Consequently, quercetin suppressed UV irradiation-induced expression of inflammatory cytokines IL-1 beta (similar to 60%)...

Compostos de terras raras, com alta absortividade no ultravioleta, como agentes de proteção de radiações solares UV-A e UV-B; Rare earth compounds with high absorptivity in uv as protection agents against UVA and UVB solar radiation

Peverari, Cinara
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 07/03/2007 PT
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A luz do sol possui radiação ultravioleta (UV) que pode ser dividida em luz UVA, com comprimentos de onda na região de 400 a 320 nm; luz UV-B, na região de 320 a 290 nm e luz UV-C para radiações com comprimento de onda menor do que 290 nm, sendo esta última absorvida na atmosfera pelo ozônio. O ser humano dispõe de mecanismos protetores naturais contra as radiações solares, tal como a melanogênese. Entretanto, estes são insuficientes e, por isso, torna-se necessário proteger adequadamente a pele utilizando protetores solares, a fim de minimizar as lesões cutâneas causadas pela radiação solar. Quimicamente, a função dos protetores solares é a absorção da radiação UV, protegendo a pele dos efeitos da exposição à luz solar. Este trabalho visa a preparação de compostos de cério, via método Pechini, com a finalidade de utilizá-los como um componente inorgânico de protetores solares de elevado FPS, juntamente ou substituindo substâncias tais como ZnO e TiO2. A caracterização dos compostos deverá ser realizada por difratometria de raios X, microscopias de eletrônicas de varredura e transmissão, espectroscopia eletrônica de reflectância difusa (ERD) e testes de atividade catalítica e fotocatalítica...

Sistemas de emissão UV-A homogêneo para uso clínico de irradiação de córneas; Homogeneous UV-A emission system for clinical use for corneas irradiation

Pereira, Fernando Ramon Ayres
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 15/10/2010 PT
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Este trabalho é parte de um projeto destinado a criar um equipamento médico, para ser aplicado com o protocolo de crosslinking de colágeno corneano, para o tratamento do ceratocone, do qual resultou o desenvolvimento de um sistema de irradiação UV-A de córneas para a aplicação clínica oftalmológica. O sistema desenvolvido neste trabalho consiste de um circuito de malha fechada, que estabiliza a potência luminosa emitida (com erro global, após a calibração, menor que 20% durante a emissão), possibilita seu ajuste até 5 mW (6,366 mW/'CM POT. 2') e permite selecionar a duração da emissão entre 10 s - 30 min. O sistema irradia com pico em 365 nm '+ OU -' 15 nm sendo que o design óptico proporciona spots homogêneos para três diâmetros selecionáveis: 10 mm; 8 mm; e 6 mm. O software desenvolvido tem a função de controlar todo o procedimento médico do crosslinking corneano, além de detectar falhas no sistema. Os resultados obtidos neste trabalho possibilitaram a criação de um equipamento robusto, flexível e estável, capaz de competir diretamente com os produtos internacionais comercializados mundialmente. Até a presente data tem-se conhecimento de apenas dois produtos, para mesma finalidade, comercializados em todo mundo...

Efeitos da radiação ultravioleta solar em algas de importância econômica da região subantártica do Chile durante a primavera; Effects of ultraviolet solar radiation on economically important algae from Chilean Sub-Antartic region during spring

Martínez, Nelso Patricio Navarro
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 02/12/2011 PT
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45.72%
Este trabalho analisou os efeitos da radiação solar UV (UV-A e UV-B) em duas espécies de importância comercial do Chile, Mazzaella laminarioides e Porphyra columbina durante a primavera, período no qual freqüentemente tem sido verificado um aumento de radiação UV-B decorrente da diminuição da camada de ozônio. A interação entre a radiação UV e o suprimento de N foi também investigada. Essa interação estimulou a síntese de aminoácidos tipo micosporinas (MAAs) nas duas espécies, durante a exposição a altas irradiâncias de UV em curtos períodos. Esses resultados sugerem um ciclo diário na síntese desses compostos. A longo prazo (18 dias de cultivo), a adição de diferentes concentrações de NO3 não promoveu diferenças no conteúdo de MAAs e no crescimento de M. laminarioides, sugerindo uma adequação do metabolismo da espécie às condições experimentais. Discute-se a mobilização do N intra-celular para a manutenção da capacidade de fotoproteção das algas. Em geral, a UV-B não promoveu efeitos deletérios no crescimento e na produção de carragenanas em tetrasporófitos e gametófitos de M. laminarioides, o que seria esperado para uma espécie do médiolitoral que está exposta a variações na quantidade e qualidade de radiação solar. Entretanto...

Efeitos da luz UV-A e visível em células da pele e no cabelo; Effects UV-A and visible light on skin cells and hair

Chiarelli Neto, Orlando
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 22/09/2014 PT
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65.72%
A luz solar apresenta ondas eletromagnéticas em ampla faixa espectral, incluindo as regiões do ultravioleta (UV-C, UV-B, UV-A), visível e infravermelho. Cada região interage com a pele de forma dependente da fotofísica e da fotoquímica dos seus respectivos compostos absorvedores. A luz UV-A causa a geração de espécies reativas de oxigênio e de nitrogênio (EROs e ERNs) através da fotossensibilização de moléculas endógenas (co-enzimas de flavina, porfirinas, melaninas). Quando fotossensibilizadores produzem quantidades de EROs e ERNs maiores do que a capacidade celular de supressão destas espécies, caracteriza-se um quadro de desbalanço redox, que causa lesão em biomoléculas como os ácidos nucleicos, lipídeos e as proteínas. Essas lesões podem levar à morte celular ou a outras transformações fenotípicas e genotípicas e também estimulam a liberação de citocinas pró-inflamatórias. Com a finalidade de melhor compreender a dinâmica dos mecanismos de resposta celular após exposição ao UV-A e ao visível, nós caracterizamos inicialmente as propriedades fotofísicas da melanina e detectamos a produção de oxigênio singlete (1O2) pela fotossensibilização no visível e a supressão desta espécie excitada pela reação do oxigênio singlete com a dupla ligação reativa dos grupos indóis presentes na melanina. Estes processos também foram observados no cabelo e levaram-nos a propor um modelo que explica o efeito da luz visível na estrutura e cor dos cabelos. Demonstramos também que a feomelanina produz mais (30%) 1O2 do que a eumelanina...

The influence of light spectra, UV-A, and growth regulators on the in vitro seed germination of Senecio cineraria DC.

Victório,Cristiane Pimentel; Silva,Nina Cláudia Barbosa da; Esquibel,Maria Apparecida; Sato,Alice
Fonte: Universidade Federal de Viçosa Publicador: Universidade Federal de Viçosa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2010 EN
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55.54%
This study was carried out to investigate the effects of light spectra, additional UV-A, and different growth regulators on the in vitro germination of Senecio cineraria DC. Seeds were surface-sterilized and inoculated in MS medium to evaluate the following light spectra: white, white plus UV-A, blue, green, red or darkness. The maximum germinability was obtained using MS0 medium under white light (30%) and MS + 0.3 mg L-1 GA3 in the absence of light (30.5%). S. cineraria seeds were indifferent to light. Blue and green lights inhibited germination. Different concentrations of gibberellic acid (GA3) (0.1; 0.4; 0.6; 0.8; 1.0 and 2.0 mg L-1) and indole-3-acetic acid IAA (0.1; 0.3 and 1.0 mg L-1) were evaluated under white light and darkness. No concentration of GA3 enhanced seed germination percentage under white light. However, when the seeds were maintained in darkness, GA3 improved germination responses in all tested concentrations, except at 1.0 mg L-1. Under white light, these concentrations also increased the germination time and reduced germination rate. Germination rate, under light or darkness, was lower using IAA compared with GA3.

Effects of UV-B radiation on Lecanicillium spp., biological control agents of the coffee leaf rust pathogen

Galvão,José A. H.; Bettiol,Wagner
Fonte: Sociedade Brasileira de Fitopatologia Publicador: Sociedade Brasileira de Fitopatologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2014 EN
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45.72%
Coffee leaf rust is the main disease of coffee and its causal agent is naturally hyperparasited by Lecanicillium lecanii, indicating its potential for biocontrol. Ultraviolet-B (UV-B) radiation is an important factor that interferes on application of biocontrol agents, and Lecanicillium can be affected by UV-B. The objective of this work was to evaluate the effects of UV-B on Lecanicillium isolates and on its capacity to colonize rust lesions. There were variations among Lecanicillium strains in sensitivity to UV-B radiation, causing inactivation and delayed spore germination. The most tolerant strain (CCMA-1143) had LD50=1.63 kJ/m² of UV-B. The incidence and colonization of Lecanicillium on coffee leaf rust lesions were influenced by the dose of UV-B radiation, and were increased when the isolate CCMA-1143 was sprayed on rust lesions. The effects of UV-B should be considered on efficacy studies for the development of biopesticides.

Expression of an Arabidopsis cryptochrome gene in transgenic tobacco results in hypersensitivity to blue, UV-A, and green light.

Lin, C; Ahmad, M; Gordon, D; Cashmore, A R
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 29/08/1995 EN
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55.53%
The Arabidopsis HY4 gene, required for blue-light-induced inhibition of hypocotyl elongation, encodes a 75-kDa flavoprotein (CRY1) with characteristics of a blue-light photoreceptor. To investigate the mechanism by which this photoreceptor mediates blue-light responses in vivo, we have expressed the Arabidopsis HY4 gene in transgenic tobacco. The transgenic plants exhibited a short-hypocotyl phenotype under blue, UV-A, and green light, whereas they showed no difference from the wild-type plant under red/far-red light or in the dark. This phenotype was found to cosegregate with overexpression of the HY4 transgene and to be fluence dependent. We concluded that the short-hypocotyl phenotype of transgenic tobacco plants was due to hypersensitivity to blue, UV-A, and green light, resulting from over-expression of the photoreceptor. These observations are consistent with the broad action spectrum for responses mediated by this cryptochrome in Arabidopsis and indicate that the machinery for signal, transduction required by the CRY1 protein is conserved among different plant species. Furthermore, the level of these photoresponses is seen to be determined by the cellular concentration of this photoreceptor.

Phytochrome A Mediates Blue Light and UV-A-Dependent Chloroplast Gene Transcription in Green Leaves1

Chun, Louis; Kawakami, Alana; Christopher, David A.
Fonte: American Society of Plant Physiologists Publicador: American Society of Plant Physiologists
Tipo: Artigo de Revista Científica
Publicado em /04/2001 EN
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55.65%
We characterized the photobiology of light-activated chloroplast transcription and transcript abundance in mature primary leaves by using the following two systems: transplastomic promoter-reporter gene fusions in tobacco (Nicotiana tabacum), and phytochrome (phyA, phyB, and hy2) and cryptochrome (cry1) mutants of Arabidopsis. In both dicots, blue light and UV-A radiation were the major signals that activated total chloroplast and psbA, rbcL, and 16S rrn transcription. In contrast, transcription activities in plants exposed to red and far-red light were 30% to 85% less than in blue light/UV-A, depending on the gene and plant species. Total chloroplast, psbA, and 16S rrn transcription were 60% to 80% less in the Arabidopsis phyA mutant exposed to blue light/UV-A relative to wild type, thus definitively linking phyA signaling to these photoresponses. To our knowledge, the major role of phyA in mediating the blue light/UV-A photoresponses is a new function for phyA in chloroplast biogenesis at this stage of leaf development. Although rbcL expression in plants exposed to UV-A was 50% less in the phyA mutant relative to wild type, blue light-induced rbcL expression was not significantly affected in the phyA, phyB, and cry1 mutants. However...

Characterization of Pseudomonas aeruginosa Bacteriophage UNL-1, a Bacterial Virus with a Novel UV-A-Inducible DNA Damage Reactivation Phenotype

Shaffer, Julie J.; Jacobsen, Lisa M.; Schrader, John O.; Lee, Kit W.; Martin, Eugene L.; Kokjohn, Tyler A.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /06/1999 EN
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UNL-1, a lytic virus of Pseudomonas aeruginosa, was observed to express a novel inducible DNA damage reactivation activity in UV-A-irradiated P. aeruginosa host cells. The expression of bacteriophage reactivation was quantified in hosts exposed to either UV-C or UV-A radiation. While reactivation of UV-C-damaged UNL-1 was not inducible in UV-C-irradiated host cells, an approximately 13-fold induction was observed in UV-A-irradiated host cells. When host cells were exposed to sunlight, reactivation of damaged UNL-1 virus increased eightfold. The UV-A induction of UNL-1 DNA damage reactivation was supported in hosts lacking recA gene function. This report is the first description of a recA-independent, UV-inducible virus DNA damage repair system. Our findings suggest that a combination of both host and virus DNA repair processes contribute to the persistence and sustained replication of some bacterial viruses in aquatic environments.

Effects of UV-A (320 to 399 Nanometers) on Grazing Pressure of a Marine Heterotrophic Nanoflagellate on Strains of the Unicellular Cyanobacteria Synechococcus spp.

Ochs, Clifford A.; Eddy, Laura P.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /01/1998 EN
Relevância na Pesquisa
55.7%
In the open ocean, where turbidity is very low, UV radiation may be an important factor regulating interactions among planktonic microorganisms. The effect of exposure to UV radiation on grazing by a commonly isolated marine heterotrophic nanoflagellate, Paraphysomonas bandaiensis, on two strains of the cyanobacteria Synechococcus spp. was investigated. Laboratory cultures were exposed to a range of irradiances of artificially produced UV-B (290 to 319 nm) and UV-A (320 to 399 nm) for up to 10 h. At a UV-B irradiance of 0.19 W m−2, but not 0.12 W m−2, grazing mortality of Synechococcus spp. and nanoflagellate-specific grazing rates were reduced compared to mortality and grazing rates with UV-A treatment. Within 6 h of exposure, UV-A alone suppressed grazing mortality at irradiances as low as 3.02 W m−2. The extent to which grazing mortality and nanoflagellate-specific grazing rates were suppressed by UV-A increased with both irradiance and duration of exposure. Over a 6-h exposure period, differences in grazing mortality were largely attributable to differential survival of nanoflagellates. Over a longer period of exposure, there was impairment by UV-A alone of nanoflagellate-specific grazing rates. Rates of primary productivity of Synechococcus spp. were also reduced by UV-A. The extent to which Synechococcus productivity was reduced...

UV-B, UV-A, and blue light signal transduction pathways interact synergistically to regulate chalcone synthase gene expression in Arabidopsis.

Fuglevand, G; Jackson, J A; Jenkins, G I
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1996 EN
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55.7%
UV and blue light stimulate transcription of key flavonoid biosynthesis genes in a range of higher plants. Here, we provide evidence that several distinct "inductive" and "synergistic" UV/blue phototransduction pathways regulate chalcone synthase (CHS) gene transcription and transcript accumulation in Arabidopsis leaf tissue. Experiments with the long-hypocotyl hy4-2.23N mutant showed that separate inductive pathways mediate responses to UV-B and UV-A/blue light. Only the UV-A/blue light induction of CHS expression involved the CRY1 photoreceptor. In addition, UV-A and blue light each act synergistically with UV-B to stimulate CHS transcript accumulation and beta-glucuronidase activity driven by a CHS promoter in transgenic leaf tissue. The UV-A and blue phototransduction pathways responsible for synergism are distinct because they produce transient and relatively stable signals, respectively, and can function additively to stimulate CHS promoter function. The hy4-2.23N mutant retains the synergistic interactions between UV-B and both UV-A and blue light, indicating that neither synergism pathway involves the CRY1 photoreceptor. Our findings reveal considerable complexity in both photoreception and signal transduction in regulating CHS gene expression by UV and blue light.

Hyperbaric oxygen preconditioning protects skin from UV-A damage

Fuller, Ashley M.; Giardina, Charles; Hightower, Lawrence E.; Perdrizet, George A.; Tierney, Cassandra A.
Fonte: Springer Netherlands Publicador: Springer Netherlands
Tipo: Artigo de Revista Científica
EN
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Hyperbaric oxygen therapy (HBOT) is used for a number of applications, including the treatment of diabetic foot ulcers and CO poisoning. However, we and others have shown that HBOT can mobilize cellular antioxidant defenses, suggesting that it may also be useful under circumstances in which tissue protection from oxidative damage is desired. To test the protective properties of hyperbaric oxygen (HBO) on a tissue level, we evaluated the ability of a preconditioning treatment regimen to protect cutaneous tissue from UV-A-induced oxidative damage. Three groups of hairless SKH1-E mice were exposed to UV-A 3 days per week for 22 weeks, with two of these groups receiving an HBO pretreatment either two or four times per week. UV-A exposure increased apoptosis and proliferation of the skin tissue, indicating elevated levels of epithelial damage and repair. Pretreatment with HBO significantly reduced UV-A-induced apoptosis and proliferation. A morphometric analysis of microscopic tissue folds also showed a significant increase in skin creasing following UV-A exposure, which was prevented by HBO pretreatment. Likewise, skin elasticity was found to be greatest in the group treated with HBO four times per week. The effects of HBO were also apparent systemically as reductions in caspase-3 activity and expression were observed in the liver. Our findings support a protective function of HBO pretreatment from a direct oxidative challenge of UV-A to skin tissue. Similar protection of other tissues may likewise be achievable.

Antioxidant Defenses and DNA Damage Induced by UV-A and UV-B Radiation in the Crab Chasmagnathus granulata (Decapoda, Brachyura)

Gouveia, Glauce Ribeiro; Marques, Daiane; Cruz, Bruno Pinto; Monserrat, Laura Alicia Geracitano; Nery, Luiz Eduardo Maia; Trindade, Gilma Santos
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
65.7%
The photoprotector role of pigment dispersion in the melanophores of the crab, Chasmagnathus granulata, against DNA and oxidative damages caused by UV-A and UV-B was investigated.Intact and eyestalkless crabs were used. In eyestalkless crabs,the dorsal epidermis of the cephalothorax (dispersed melanophores)and the epidermis of pereiopods aggregated melanophores)were analyzed. Intact crabs showed only dispersed melanophores in the two epidermis. Antioxidant enzymes activity and lipoperoxidation content were analyzed after UV-A (2.5 J/cm2) or UV-B (8.6 J/cm2) irradiation. DNA damage was analyzed by single cell electrophoresis (comet) assay, after exposure to UV-B (8.6 J/cm2). UV-A radiation increased the glutatione-S-transferase activity in the pereiopods epidermis of eyestalkless crabs (P < 0.05). UV-B radiation induced DNA damage in the dorsal epidermis of eyestalkless crabs (P < 0.05). In pereiopod epidermis of eyestalkless crabs, there was no significant difference between control and UV-B???exposed crabs. In the pereiopods epidermis of eyestalkless, the control group showed higher scores of DNA damage and ~50% of cellular viability. Because in eyestalkless and irradiated crabs the cellular viability was ~5%...

Effect of ultraviolet (UV) radiation on the abundance and respiration rates of probiotic bacteria

Garrido-Pereira, Maria Ang??lica dos Reis; Braga, Andr?? Luiz; Rocha, Andr??a Ferretto da; Sampaio, Lu??s Andr??; Abreu, Paulo C??sar
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
45.74%
Effects of ultraviolet radiation (UV) on probiotic bacteria (Bacillus subtilis and B. licheniformis) were tested in two experiments, with the following treatments: (i) UV treatment ??? using fluorescent and UV-lamps and (ii) Control ??? CTRL, using fluorescent lamps. Bacterial abundance and respiration were evaluated every 24 h for 3 days for Experiment 1, and at 0, 6 and 24 h for Experiment 2. In the Experiment 1, total UV dose was 4 336.41 mW cm _2. UV treatment presented small respiration rates only on day 3, while in the CTRL oxygen consumption was always high. On all days, the abundance of the Bacilli exposed to UV was significantly smaller than that of the CTRL. The second experiment, with total UV dose of 1 445.47 mW cm _2, presented oxygen consumption in the UV treatment only during the first 6 h. In the CTRL, oxygen consumption increased from the beginning due to the bigger abundance Bacilli cells. Small coccus-shaped bacteria occurred in the UV treatment of both experiments. It may be concluded that exposure to UV, normally used for water disinfection, can inactivate probiotic bacteria.

Auswirkung des Crosslinking der Kornea mittels UV-A-Strahlung und Riboflavin auf den intraokularen Druck und die Ultrastruktur am Vorderkammermodell des Schweins

Ottmann, Oliver
Fonte: Universität Tübingen Publicador: Universität Tübingen
Tipo: Dissertação
DE
Relevância na Pesquisa
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Hintergrund: Der Keratokonus ist eine meist bilaterale, nicht-entzündliche Ektasie der Kornea, die im meist progredienten Verlauf eine starke Einschränkung der Sehleistung verursacht. Meist sind jüngere Patienten betroffen, die Erkrankungsgipfel liegen zwischen dem 17. und 49. Lebensjahr. Bisherige Therapien waren rein symptomatisch wie die Anpassung ausgleichender Sehhilfen oder letztlich eine Keratoplastik mit entsprechenden Risiken. Seit mehreren Jahren nun wird mittels Crosslinking (Cxl) ein vielversprechender Ansatz verfolgt der das Fortschreiten des Keratokonus kausal aufhalten kann. Da es sich um meist sehr junge Patienten mit entsprechendem Langzeitverlauf handelt ist das Verständnis der möglichen Komplikationen und Nebenwirkungen sehr wichtig. Mehrere Studien haben sich bereits mit diesen beschäftigt; unter anderem mit der Problematik des IOP (intraokulärer Druck) und dessen Messung. Hier lagen bisher sehr unterschiedliche Ergebnisse vor. Ziel dieser Arbeit war es zu klären ob es im Modell intraokular zu einer Druckerhöhung nach Cxl kommt. Methoden: Es wurden insgesamt 35 Schweineaugen bzw. die Vorderkammer im Perfusionsmodell nach Johnsen und Tschumper untersucht. 20 Augen wurden mittels Cxl behandelt, 15 Augen dienten als Methodenkontrolle. Die Auswertung erfolgte in Kohorten zu je 5 Augen. Die Dauer der Nachbeobachtung betrug 48 h. Darüber hinaus wurden 8 Vorderkammern...

Etude du rôle de la réponse UV sur le contrôle de la réparation par excision de nucléotides (NER) des dommages à l’ADN : rôle des voies MAPK et de l’ADN polymérase eta

Rouget, Raphael
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
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45.73%
La réponse cellulaire aux ultra-violets (UV), ou réponse UV, est une réponse complexe et spécialisée dans l’adaptation et la tolérance des dommages aux UV. Celle-ci est initiée par un grand nombre d’évènements moléculaires et de signalisation nucléaire mais aussi au niveau de la membrane plasmique ou du cytoplasme. L’importance et l’influence exactes de ces évènements sur la réparation par excision de nucléotides (NER) des dommages UV à l’ADN sont encore mal comprises et doivent encore être méthodiquement démontrées. Dans cette thèse, grâce à l’utilisation d’une méthode sensible d’analyse de la réparation NER basée sur la cytométrie en flux, il est montré, dans un premier temps, que l’activité des voies MAPK (Mitogen-Activated Protein Kinases), qui sont des voies de signalisation de stress UV d’origine cytoplsamique, ne participent pas à l’efficacité de réparation NER des dommages UV dans les cellules humaines. En effet, l’abrogation de la signalisation MAPK, par inhibition pharmacologique, par utilisation de mutants dominant-négatifs ou par inhibition de leur expression endogène, ne révèlent aucun changement de la cinétique de réparation des dommages UV par excision de nucléotides. Cependant...

Treatment of T. cruzi infected human platelet concentrates with aminomethyltrimethyl psoralen (AMT) and ultravioleta (UV-A) light: preliminary results

Moraes-Souza,Hélio; Bordin,José Orlando; Bardossy,Leslie; Blajchman,Morris A.
Fonte: Sociedade Brasileira de Medicina Tropical - SBMT Publicador: Sociedade Brasileira de Medicina Tropical - SBMT
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/1996 EN
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75.68%
The present measures adopted to prevent transfusion-associated Chagas' disease include screening of blood donors. and/or the inactivation of T. cruzi in collected blood using gentian violet (GV) as a trypanocidal agent. In this study, we investigated the efficacy of the combined use of AMT and UV-A in inactirating T. cruzi in infected human platelet cuncentrates. Human platelet concentrates were infected with T. cruzi (2x10/ml) of the Y strain transfered to PL 269 (Fenwal Laboratories) containers and treated with GV (250řg,/ml). and ascorbic acid (1 mg/ml); GV. ascorbic acid and UV-A; GV and UV-A; AMT (40/tG/ml) and ascorbic acid; AMT, ascorbic acid and UV-A; AMT and UV-A; UV-A alone; and untreated (control). All UV-A treated platelet concentrates were exposed to UV-A doses of 24, 92, 184, 276, 368 and 644 kj/m². and the microscopical research of active T. cruzi was performed, using the microhematocrit technique, 1, 6 and 24 hours after each treatment. A high number of active forms of T. cruzi was observed in all condictions, except when GV was used as the trypanocidal agent, providing evidence of the failure of AMT and UV-A in inactivating T cruzi in infected human platelet concentrates.

In vivo activation of human immunodeficiency virus type 1 long terminal repeat by UV type A (UV-A) light plus psoralen and UV-B light in the skin of transgenic mice.

Morrey, J D; Bourn, S M; Bunch, T D; Jackson, M K; Sidwell, R W; Barrows, L R; Daynes, R A; Rosen, C A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1991 EN
Relevância na Pesquisa
55.7%
UV irradiation has been shown to activate the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) in cell culture; however, only limited studies have been described in vivo. UV light has been categorized as UV-A (400 to 315 nm), -B (315 to 280 nm), or -C (less than 280 nm); the longer wavelengths are less harmful but more penetrative. Highly penetrative UV-A radiation constitutes the vast majority of UV sunlight reaching the earth's surface but is normally harmless. UV-B irradiation is more harmful but less prevalent than UV-A. In this report, the HIV-1 LTR-luciferase gene in the skin of transgenic mice was markedly activated when exposed to UV-B irradiation. The LTR in the skin of transgenic mice pretreated topically with a photosensitizing agent (psoralen) was also activated to similar levels when exposed to UV-A light. A 2-h exposure to sunlight activated the LTR in skin treated with psoralen, whereas the LTR in skin not treated with psoralen was activated after 7 h of sunlight exposure. The HIV-1 LTR-beta-galactosidase reporter gene was preferentially activated by UV-B irradiation in a small population of epidermal cells. The transgenic mouse models carrying HIV-1 LTR-luciferase and LTR-beta-galactosidase reporter genes have been used to demonstrate the in vivo UV-induced activation of the LTR and might be used to evaluate other environmental factors or pharmacologic substances that might potentially activate the HIV-1 LTR in vivo.

Fotocontrol de la productividad y elongación detallos de tres cultivares de Rosa x hybrida L. bajocubiertas de polietileno fotoselectivas

Mascarini,Libertad; Lorenzo,Gabriel A; Burgos,Marcelo L
Fonte: Revista de la Facultad de Ciencias Agrarias. Universidad Nacional de Cuyo Publicador: Revista de la Facultad de Ciencias Agrarias. Universidad Nacional de Cuyo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2013 ES
Relevância na Pesquisa
55.45%
Se evaluaron los cambios en la radiación transmitida a través de films fotoselectivos (FS) fluorescentes y el impacto de estos cambios sobre la producción de tres cultivares de rosa para corte Fuego Negro, Maroussia y Anna. Se observó que los FS nuevos o expuestos a la radiación solar vs. noFS disminuyen la transmisión de radiación azul (A) (-28,4 a -32,9%, respectivamente), incrementan el R produciendo una relación R:RL mayor (+3,6%), si bien transmiten algo menos de radiación fotosintéticamente activa que los noFS nuevos. El número de rosas producidas fue significativamente mayor bajo el FS vs. noFS en los tres cv (+24, +32 y +36% en Anna, Fuego Negro y Maroussia, respectivamente), con un peso fresco y seco (PF y PS) significativamente mayor y tallos florales más largos en Anna y Maroussia (50,69 y 43,91 cm vs. 38,91 y 40,04 cm en invierno y primavera, respectivamente), y pimpollos significativamente más largos y de mayor PF y PS en los tres cv. Mayor relación R:RL y menor UV-A y A en la radiación transmitida por films FS aumentaron la cantidad y calidad de determinados cultivares de rosas mostrando una alternativa a los reguladores químicos de crecimiento.