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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.
51

Determination and analysis of multi photon excitation e missive species.

Turner, Joseph B. McGee, January 2005 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2005. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (May 23, 2006) Vita. Includes bibliographical references.
52

Tratamento de periodontite crônica com múltiplos episódios de terapia fotodinâmica antimicrobiana (aPDT) ou com uso sistêmico de amoxicilina e metronidazol : estudo clínico randomizado /

Lopes, Alessandra Barreto. January 2016 (has links)
Orientador: Letícia Helena Theodoro / Coorientadora: Cristiane Duque / Banca: Juliano Milanezi de Almeida / Cristina Cunha Villar / Resumo:Objetivo: Este estudo comparou por meio de a nálise clínica os efeitos da Amoxicilina associado ao Metronidazol (MTZ+AMX ) e de múltiplas aplicações da terapia fotodinâmica antimicrobiana (aPDT) como coadjuvantes ao t ratamento da periodontite crônica . Métodos: Um estudo clín ico controlado, randomizado foi conduzido em 34 pacientes que receberam: Grupo MTZ+AMX (n=17) - raspagem e al isamento radicular (RAR) e uso sistêmico de Metronidazol (400 mg 3 X por dia, 7 dias) e Amoxicili na (500 mg 3 X por dia, 7 dias) e; Grupo aPDT (n=17) - raspagem e alisamento radicular (RAR) e 3 aplicações de aPDT em todos os sítios com profundidade de son dagem maior que 4 mm imediatamente, 48 e 96 ho ras após a RAR e placebo durante 7 dias. Os exames clínicos foram realizados no início, aos 90 e 180 dias após o tratamento. Os parâmetros clínicos de índice de placa visível (IPV), san gramento à sondagem (SS), profundidad e de sondagem (PS) e nível de inserção clínico (NIC) foram avaliados. A aPDT foi realizada, utilizando o azul de metileno (10 mg/mL ) e o laser de diodo de Arsênio - Galio - Alumínio (AsGaAl) em baixa int ensidade após 1 minuto (660 nm, 100 mW, 48 segundos, 160 J/cm 2 ) imediatamente, 48 e 96 hs após o trata mento, em t odos os sítios com profundidade de sondagem maior que 4 mm . Os dados c línicos foram estatisticamente analisados (α=5%). Resultados: Na análise intragrupo da PS, não foram encontradas di ferenças estatisticamente significativas entre as médias de boca toda entre os três períodos do estudo em ambos os grupos. Não houve diferenças estatisticamente significativas na PS entre os grupos ava liados em cada período (P>0,05). Com relação ao NIC em ambos os grupos houve ganho de inserção estatisticamente significante aos 90 dia s quando comparado ao baseline (P<0,05). Houve redução de SS ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Aim: This study compared, through clinical analysis, the effects of Amoxicilli n associated with metronidazole (MTZ+AMX), and multiple applications of antimicrobial photodynamic therapy (aPD T), as adjuncts therapy in the treatment of chronic periodontitis. Methods: A controlled randomized clinical trial was conducted in 34 patients, divided into two groups: the MTZ+AMX Group (n=17), subjected to scaling and root planing (SRP) with systemic use of Metronidazole (400 mg 3 X per day 7 days) and Amoxicillin (500 mg 3 X per day 7 days); and the aPDT Group (n=17), submitted to SRP and three aPDT applications in a ll sites with a probing depth larger than 4 mm, immediately 48 and 96 hours after scaling, and placebo during 7 days. Clinical examinations were performed at the baseline, 3 and 6 months post - therapy. The clinical parameters visible plaque index (VPI), ble eding on probing (BOP), probing depth (PD), and clinical attachment level (CAL) were measured. The aPDT was carried out using methylene blue (10 mg/mL ) and the Gallium - Aluminum - Arsenide (GaAlAs) laser at 1 minute (660 nm, 100 mW, 48 seconds, 160 J/cm²) 48 and 96 hours immediately after treatment, in all si tes with a probing deeper than 4 mm. Subsequently, statistical analysis was performed (α=5%). Results: Intra group analysis did not reveal statistically significant differences between mean mouth in PD in all three stages o f the study in either group s . In additio n, there were no statistically significant differences in PD between the groups in each period (P> 0.05) . With regard to the CAL both groups there was a sta tistically significant gain at 90 days compared to the baseline (P <0.05). In both groups there was a reduction in BOP and the percentage of residual pockets after 90 and 180 days compared to the baseline (P<0.05). Conclusion: Both adjunct therapies ...(Complete abstract electronic access below) / Mestre
53

Efeito da terapia fotodinâmica antimicrobiana sobre culturas planctônicas e biofilmes de bactérias e fungos utilizando curcumina e cloro-alumínio ftalocianina veiculada por nanoemulsões

Ribeiro, Ana Paula Dias [UNESP] 30 March 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:35:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-03-30Bitstream added on 2014-06-13T20:25:45Z : No. of bitstreams: 1 ribeiro_apd_dr_arafo.pdf: 832813 bytes, checksum: 759c5af5e6cd507196080c8dc6e34faa (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Esta investigação teve os seguintes objetivos: 1. avaliar in vitro o efeito da Terapia Fotodinâmica (PDT) utilizando diferentes concentrações de curcumina e doses de luz LED na inativação de suspensões planctônicas de S. aureus resistente (MRSA) e susceptível à meticilina (MSSA) e a citotoxicidade dos parâmetros antimicrobianos dessa terapia em cultura celular de fibroblastos; 2. o efeito fotodinâmico da cloro-alumínio ftalocianina (ClAlFt) veiculada em nano-emulsão catiônica e aniônica e comparar com ClAlFt diluída em solvente orgânico na inativação da C. albicans quando em suspensão planctônica e organizados em biofilmes; 3. o efeito antimicrobiano da terapia fotodinâmica utilizando a cloroalumínio ftalocianina em sistema de nanoemulsão em culturas planctônicas e biofilmes de bactérias gram-positivas (MSSA e MRSA). No primeiro estudo, suspensões de MSSA e MRSA foram tratadas com diferentes concentrações de curcumina (entre 0,1 a 20,0 μM) e expostas a diferentes fluências de LED azul (18; 25 e 37,5 J/cm2). Em seguida, diluições seriadas foram obtidas e alíquotas de 25 μl de cada diluição foram plaqueadas em meio de cultura Mannitol Salt Agar. Após o período de incubação de 48 horas a 37°C, as unidades formadoras de colônias foram determinadas (UFC/mL). Para as células L929, essas foram incubadas por 20 minutos com curcumina e irradiadas em seguida com LED (37,5 J/cm2). A viabilidade celular após a PDT foi avaliada utilizando o teste de MTT e as alterações morfológicas foram avaliadas pela microscopia eletrônica de varredura (MEV). Os resultados foram submetidos à análise descritiva, Análise de Variância (ANOVA) e post hoc de Tukey (α= 5%). As concentrações de 5, 10 e 20 μM resultaram em completa inativação do MSSA quando associadas a qualquer fluência de energia... / The aim of this investigation was to evaluate: 1. the Photodynamic Therapy (PDT) mediated by curcumin for in vitro inactivation of methicillin-resistant S. aureus (MRSA) and susceptible S. aureus (MSSA) and its citotoxic effects against L929 fibroblasts; 2. the photodynamic potential of aluminum-chloride-phthalocyanine (ClAlPc) entrapped in cationic and anionic nanoemulsions (NE) to inactivate C. albicans planktonic and biofilm cultures compared with free ClAlPc; 3. the photodynamic effect of ClAlPc encapsulated in NE on methicillin susceptible and resistant S. aureus suspensions and biofilms. In the first study, suspensions of MSSA and MRSA were treated with different concentrations of curcumin and exposed to LED. Serial dilutions were obtained from each sample, and colony counts were quantified. For fibroblasts, the cell viability subsequent to the curcumin-mediated photodynamic therapy was evaluated using the MTT assay and morphological changes were assessed by SEM analysis. Curcumin concentrations ranging from 5.0 to 20.0 μM in combination with any tested LED fluences resulted in photokilling of MSSA. However, only the 20.0 μM concentration in combination with highest fluence resulted in photokilling of MRSA. This combination also promoted an 80% reduction in fibroblast cell metabolism and morphological changes were present, indicating that cell membrane was the main target of this phototherapy. In the second study, fungal suspensions were treated with different types of delivery systems containing ClAlPc. After 30 minutes, the drug was washed-out and samples were illuminated with LED source (660 ± 3 nm). Negative control samples were not exposed to ClAlPc or light. For planktonic suspensions, colonies were counted (CFU/ml) and cell metabolism was evaluated by XTT assay. (Kruskal-Wallis and... (Complete abstract click electronic access below)
54

Efeito da terapia fotodinâmica antimicrobiana sobre culturas planctônicas e biofilmes de bactérias e fungos utilizando curcumina e cloro-alumínio ftalocianina veiculada por nanoemulsões /

Ribeiro, Ana Paula Dias. January 2012 (has links)
Orientador: Ana Claudia Pavarina / Banca: Ana Lúcia Machado / Banca: Francisco de Assis Nollo Junior / Banca: Helena de Freitas Oliveira Paranhos / Banca: Soraya Coelho Leal / Resumo: Esta investigação teve os seguintes objetivos: 1. avaliar in vitro o efeito da Terapia Fotodinâmica (PDT) utilizando diferentes concentrações de curcumina e doses de luz LED na inativação de suspensões planctônicas de S. aureus resistente (MRSA) e susceptível à meticilina (MSSA) e a citotoxicidade dos parâmetros antimicrobianos dessa terapia em cultura celular de fibroblastos; 2. o efeito fotodinâmico da cloro-alumínio ftalocianina (ClAlFt) veiculada em nano-emulsão catiônica e aniônica e comparar com ClAlFt diluída em solvente orgânico na inativação da C. albicans quando em suspensão planctônica e organizados em biofilmes; 3. o efeito antimicrobiano da terapia fotodinâmica utilizando a cloroalumínio ftalocianina em sistema de nanoemulsão em culturas planctônicas e biofilmes de bactérias gram-positivas (MSSA e MRSA). No primeiro estudo, suspensões de MSSA e MRSA foram tratadas com diferentes concentrações de curcumina (entre 0,1 a 20,0 μM) e expostas a diferentes fluências de LED azul (18; 25 e 37,5 J/cm2). Em seguida, diluições seriadas foram obtidas e alíquotas de 25 μl de cada diluição foram plaqueadas em meio de cultura Mannitol Salt Agar. Após o período de incubação de 48 horas a 37°C, as unidades formadoras de colônias foram determinadas (UFC/mL). Para as células L929, essas foram incubadas por 20 minutos com curcumina e irradiadas em seguida com LED (37,5 J/cm2). A viabilidade celular após a PDT foi avaliada utilizando o teste de MTT e as alterações morfológicas foram avaliadas pela microscopia eletrônica de varredura (MEV). Os resultados foram submetidos à análise descritiva, Análise de Variância (ANOVA) e post hoc de Tukey (α= 5%). As concentrações de 5, 10 e 20 μM resultaram em completa inativação do MSSA quando associadas a qualquer fluência de energia... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this investigation was to evaluate: 1. the Photodynamic Therapy (PDT) mediated by curcumin for in vitro inactivation of methicillin-resistant S. aureus (MRSA) and susceptible S. aureus (MSSA) and its citotoxic effects against L929 fibroblasts; 2. the photodynamic potential of aluminum-chloride-phthalocyanine (ClAlPc) entrapped in cationic and anionic nanoemulsions (NE) to inactivate C. albicans planktonic and biofilm cultures compared with free ClAlPc; 3. the photodynamic effect of ClAlPc encapsulated in NE on methicillin susceptible and resistant S. aureus suspensions and biofilms. In the first study, suspensions of MSSA and MRSA were treated with different concentrations of curcumin and exposed to LED. Serial dilutions were obtained from each sample, and colony counts were quantified. For fibroblasts, the cell viability subsequent to the curcumin-mediated photodynamic therapy was evaluated using the MTT assay and morphological changes were assessed by SEM analysis. Curcumin concentrations ranging from 5.0 to 20.0 μM in combination with any tested LED fluences resulted in photokilling of MSSA. However, only the 20.0 μM concentration in combination with highest fluence resulted in photokilling of MRSA. This combination also promoted an 80% reduction in fibroblast cell metabolism and morphological changes were present, indicating that cell membrane was the main target of this phototherapy. In the second study, fungal suspensions were treated with different types of delivery systems containing ClAlPc. After 30 minutes, the drug was washed-out and samples were illuminated with LED source (660 ± 3 nm). Negative control samples were not exposed to ClAlPc or light. For planktonic suspensions, colonies were counted (CFU/ml) and cell metabolism was evaluated by XTT assay. (Kruskal-Wallis and... (Complete abstract click electronic access below) / Doutor
55

Multi-functional upconversion nanoparticles for in vivo imaging, in vivo tumor suppression and photodynamic therapy

Chan, Chi Fai 11 February 2016 (has links)
Upconversion nanoparticles (UCNPs) have been utilized for biological applications. Unlike conventional linear excitation molecules, UCNPs are excited by 980nm and emit photon in visible and near infrared region. The unique photophysical property offers superior penetration depth and lower photo-cytotoxicity. With the aid of various vectors such as target-specific peptides and photosensitizers, the UCNPs can precisely interact selectively with designated proteins (Cyclin D1 and Polo-like Kinase 1) and cancer cells so as to achieve theranostic effect. This thesis illustrated the upconversion mechanism and anti-cancer effect by UCNPs conjugated with peptides. Two research studies focus on Cyclin D1 or Polo-like kinase 1 (Plk1) specific peptides coated UCNPs function as key cell cycle inhibitors, in vitro imaging agent and in vivo tumor suppressor. Apart from inorganic nanomaterials, graphitic phase carbon nitride (g-C3N4) nanoparticles coupled with porphyrin moieties act as cancer directional photodynamic therapy agents was also described in the aspects of detailed photophysical measurements and in vitro theranostic studies.
56

Efeito sinérgico entre a terapia fotodinâmica e a cisplatina : uma nova abordagem para o câncer de colo uterino /

Freitas, Laura Marise de. January 2015 (has links)
Orientador: Carla Raquel Fontana / Coorientador: Christiane Pienna Soares / Banca: Alexandra Ivo de Medeiros / Banca: Kleber Thiago de Oliveira / Resumo: O câncer de colo uterino (ou câncer cervical) é uma neoplasia maligna que tem a infecção pelo HPV como o principal fator de risco para o seu surgimento. As terapias atuais para o tratamento do câncer cervical têm como maior desvantagem a excisão substancial do estroma cervical e muitos efeitos adversos associados aos quimioterápicos, principalmente a cisplatina. Nesse cenário, a terapia fotodinâmica (TFD) vem se mostrando uma alternativa promissora, especialmente se combinada a tratamentos convencionais. A técnica é baseada na administração de um agente fotossensibilizador não tóxico ao paciente com posterior exposição a uma fonte de luz de comprimento de onda específico, resultando em resposta citotóxica via dano oxidativo. Diante disso, o presente estudo teve como objetivo avaliar, in vitro, a citotoxicidade, o tipo de morte induzido e os efeitos genotóxicos e mutagênicos da TFD em monoterapia e associada à cisplatina sobre as linhagens SiHa, C-33 A e HaCaT, utilizando os fotossensibilizadores Photogem e azul de metileno. Observou-se que tanto a terapia fotodinâmica mediada por azul de metileno (AMTFD) quanto a terapia mediada pelo Photogem (PGTFD) foram eficazes em reduzir o número de células viáveis, com a citotoxicidade sendo dependente da dose de luz. A cisplatina teve menor eficácia sobre as três linhagens quando comparada à TFD. Porém, a combinação cisplatina + TFD apresentou efeito sinérgico intenso e provocou maior morte celular em todas as condições testadas. A sequência de aplicação dos tratamentos (cisplatina + TFD ou TFD + cisplatina) demonstrou-se importante e dependente do fotossensibilizador. Com relação ao tipo de morte celular provocado, tanto a AMTFD quanto a PGTFD induziram morte independente de caspases, mas a AMTFD induziu morfologia típica de necrose, enquanto a PGTFD induziu morfologia mais similar à apoptose. A cisplatina induziu predominantemente apoptose e as terapias... / Abstract: Cervical cancer is a malignant tumor that has HPV infection as the main risk factor for its emergence. Current therapies for the treatment of cervical cancer have as major disadvantage substantial excision of cervical stroma and many adverse effects associated with chemotherapy, especially cisplatin. In this scenario, photodynamic therapy (PDT) has proven to be a promising alternative, specially if combined with conventional treatments. The technique is based on the administration of a non-toxic photosensitizing agent to the patient with subsequent exposure to a light source of a specific wavelength, resulting in cytotoxic response by oxidative damage. Thus, the present study intended to evaluate in vitro cytotoxicity, the type of induced death and the genotoxic and mutagenic effects of PDT alone and associated with cisplatin on the cell lines SiHa, C-33 A and HaCaT, using the photosensitizers Photogem and methylene blue. It was observed that both the photodynamic therapy mediated by methylene blue (MBPDT) and Photogem mediated therapy (PGPDT) were effective in reducing cell viability with cytotoxicity being dependent on the light dose. Cisplatin was less effective over the three lines compared to PDT. However, the combination cisplatin + PDT had a greater synergistic effect and caused greater cell death in all conditions tested. The sequence of treatment application (PDT + cisplatin or cisplatin + PDT) was important and depended on the photosensitizer. Regarding the type of induced cell death, both AMPDT and PGPDT induced caspase-independent death, but AMPDT induced the typical morphology of necrosis, while PGPDT induced morphology was most similar to apoptosis. Cisplatin predominantly induced apoptosis; and combination therapy induced greater apoptosis- or necrosis-like rate according to the cell line, but always with a higher percentage of dead cells than monotherapies. MBPDT, either as monotherapy or in combination with cisplatin was ... / Mestre
57

estudo in situ do efeito antimicrobiano da terapia fotodinÃmica em lesÃes de cÃrie dentinÃria / In situ study of the antimicrobial effect of photodynamic therapy in dentine caries lesions

Juliana Paiva Marques Lima 04 March 2009 (has links)
Terapia fotodinÃmica à um conceito de tratamento, sugerido pela literatura como uma potencial terapia capaz de proporcionar inativaÃÃo microbiana. Desta forma, este estudo avaliou a aÃÃo da terapia fotodinÃmica sobre lesÃes de cÃrie dentinÃria, mediante um delineamento in situ de Ãnica fase. Durante 14 dias, 20 voluntÃrios utilizaram dispositivos intra-orais palatinos, contendo, cada um, seis blocos de dentina humana. Todos os voluntÃrios foram instruÃdos a gotejar sobre os blocos uma soluÃÃo de sacarose a 40% dez vezes ao dia, simulando um desafio cariogÃnico e a utilizar dentifrÃcio fluoretado trÃs vezes ao dia. No final deste perÃodo clÃnico, os blocos foram randomicamente alocados em um dos seguintes grupos: sem fotossensibilizador e luz (F-L-); com fotossensibilizador e sem luz (F+L-); sem fotossensibilizador e com luz com densidade de energia de 47J/cm2(F-L+47); sem fotossensibilizador e com luz com densidade de energia de 94J/cm2 (F-L+94); com fotossensibilizador e irradiados com densidade de energia de 47J/cm2(F+L+47); com fotossensibilizador e irradiados com densidade de energia de 94J/cm2(F+L+94). O fotossensibilizador de escolha foi azul de orto-toluidina na concentraÃÃo de 100 &#61549;g/mL e a irradiaÃÃo originada de um diodo emissor de luz (LED) com comprimento de onda predominante em 638,8nm. Amostras de dentina cariada de cada bloco foram coletadas antes e apÃs os tratamentos e analisadas para contagem de microorganismos totais, estreptococos totais, estreptococos grupo mutans e lactobacilos. Os dados das contagens foram transformados em log10, os valores de log reduÃÃo foram obtidos e as diferenÃas estatÃsticas identificadas atravÃs dos testes ANOVA One way e Tukey Kramer (p<0,05). Em ambas as anÃlises, foram observadas diferenÃas estatisticamente significativas entre as contagens microbiolÃgicas antes e depois dos tratamentos nos grupos (F-L+94), (F+L+47), (F+L+94) para todos os microrganismos testados. Concluiu-se que a terapia fotodinÃmica foi efetiva na morte microbiana nos parÃmetros testados e que o tempo de exposiÃÃo da dentina à luz de 10 minutos, tambÃm, promoveu inativaÃÃo microbiana. / Photodynamic therapy is a concept of treatment, suggested by the literature as a potential therapy capable of inactivating microbial. Thus, this study assessed the efficacy of photodynamic therapy on injuries of dentine caries by a in situ design of single phase. During 14 days, 20 volunteers wore intra-oral palatal devices containing six human dental dentine slabs. The volunteers wore asked to drop a 40% sucrose solution onto the slabs ten times per day, in order to simulate a cariogenic challenge and to use fluoride dentifrice three times per day. At the end of the experimental period the slabs were randomly allocated into one of the following groups: without sensitizer and light (S-L-); with sensitizer and without light (S+L-); without sensitizer and irradiated with 47J/cm2 energy density (S-L+47); without sensitizer and irradiated with 94J/cm2 energy density (S-L+94); with sensitizer and irradiated with 47J/cm2 energy density (S+L+47); and with sensitizer and irradiated with 94J/cm2 energy density (S+L+94). The sensitizer of choice was the toluidine blue O at 100 &#61549;g/mL concentration and radiation originated from a light-emitting diode (LED) with a 638,8 nm predominant wavelength. Before and after the treatments, dentine samples were collected and analyzed to figure out the total microorganisms, total streptococci, mutans streptococci and lactobacilli. The data of the counts were transformed into log10.The values of log reduction was achieved and the statistical differences identified by ANOVA One way and Tukey Kramer tests (p<0,05). In both analyses statistically significant difference between the microbial counts before and after treatment in groups (S-L+47), (S+L+94), (S+L+94) for all microorganisms tested are founded. It was concluded that PACT in the tested parameters was effective in promoting microbial death and that the exposure time of dentine to 10 minutes of light was also effective in microbial inactivation.
58

Effectiveness of zinc-phthalocyanine and hypericin in inducing cell death in human breast cancer cells (mcf-7) using low intensity laser irradiation (lili)

Mfouo-Tynga, Ivan Sosthene 09 December 2013 (has links)
M.Tech. (Biomedical Technology) / The uncontrolled growth of cells in the body is often associated with cancer. It constitutes a major health problem and is one of the leading causes of death in the world. Cancers of the lung, breast, colon/rectum and prostate are no longer only associated with developed countries but are the most common occurring cancers worldwide. Breast cancer is the leading cancer faced by women in South Africa as well as in the world. Conventional cancer therapies often result in uncertain outcomes with numerous side effects and may be associated with limited therapeutic advantage. This has led to the development of safer and better treatment regimes with improved therapeutic outcomes. Photodynamic therapy (PDT) is a treatment used for a wide range of conditions, including cancer. This treatment utilises a photosensitiser (PS), a light activated chemotherapeutic agent, and light of a specific wavelength and power density. It is based on the selective tumour localisation of the PS and the ability to generate high levels of reactive oxygen species (ROS) in the presence of light. The generation of ROS causes permanent damage to the tumour cells resulting in cancer cell death. The distinctive criteria when comparing different PDT modalities is the choice of PS as the treatment outcomes are greatly influenced by the light dependent properties of the chemotherapeutic agent. Phthalocyanines are second generation PSs used in PDT. Effects of members of this PS family have been studied and they exhibited good photosensitising properties including lack of cytotoxicity in the absence of light, extended retention times in the tumour and high triplet lifetime of singlet oxygen species.
59

Role of p38 mitogen-activated protein kinases in hypericin photodynamic therapy-induced apoptosis of nasopharyngeal carcinoma HK-1 cells

Chan Pui Shan, 01 January 2008 (has links)
No description available.
60

Theranostic porphyrin-cyclen gadolinium complex for photodynamic therapy and magnetic resonance imaging

Fok, Wanyiu 30 August 2019 (has links)
Photodynamic therapy (PDT) and Magnetic resonance imaging (MRI) are two techniques used in therapeutic and diagnostic purpose respectively. PDT can selectively kill the cancer cells by utilizing light and photosensitizer, while MRI provides invasive imaging on our interior bodies. If these two techniques combine, the probe can act as both PDT and MRI agent at the same time. This theranostic agents can bring great efficiency in the cancer treatment. In this project, a porphyrin-cyclen gadolinium based dual functions bio-probe, PZnGdL, is designed for diagnostic and photodynamic therapeutic functions. PZnGdL demonstrated a great T1 signal enhancement for MRI, in which its T1 relaxivity is 15.06 mM-1s-1 (at 1.4T, 37oC). The T1 relaxivity is five-fold higher than the clinically approved MRI contrasting agent Gd-DOTA, (2.92 at 1.4T, 37oC). Furthermore, PZnGdL exhibits low dark toxicity and high photocytotoxicity. Therefore, its photodynamic therapeutic index (PDI) in HeLa cells is as high as 1348 upon 1 J/cm2 light irradiation. Results from the present study show that PZnGdL is an effective photodynamic therapy agent as well as a safe and promising MRI contrasting agent.

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