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Photodynamic antimicrobial chemotherapy (PACT) for the treatment of malaria, leishmaniasis and trypanosomiasis

BAPTISTA, M.S.; WAINWRIGHT, M.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica
ENG
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A photodynamic effect occurs when photosensitiser molecules absorb light and dissipate the absorbed energy by transferring it to biological acceptors (usually oxygen), generating an excess of reactive species that are able to force cells into death pathways. Several tropical diseases present physiopathological aspects that are accessible to the application of a photosensitiser and local illumination. In addition, disease may be transmitted through infected blood donations, and many of the aetiological agents associated with tropical diseases have been shown to be susceptible to the photodynamic approach. However, there has been no systematic investigation of the application of photoantimicrobial agents in the various presentations, whether to human disease or to the disinfection of blood products or even as photo-insecticides. We aim in this review to report the advances in the photoantimicrobial approach that are beneficial to the field of anti-parasite therapy and also have the potential to facilitate the development of low-cost/high-efficiency protocols for underserved populations.

In vivo study of laser irradiation of fractionated drug administration based mechanism for effective photodynamic therapy in rat liver

Khurshid, A.; Firdous, S.; Ahmat, L.; Ferraria, J.; Vollet-Filho, J. D.; Kurachi, Cristina; Bagnato, Vanderlei Salvador; Nawaz, M.; Ikram, M.; Ahmad, M.
Fonte: MAIK NAUKA/INTERPERIODICA/SPRINGER; NEW YORK Publicador: MAIK NAUKA/INTERPERIODICA/SPRINGER; NEW YORK
Tipo: Artigo de Revista Científica
ENG
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Up-regulation of stress-activated proteins in cancer cells plays a protective role against photodynamic induced apoptosis. Post photodynamic therapy extracted normal rat liver tissue usually shows a fraction of surviving cells, the photodynamic resistant cells, residing in the necrotic region. To treat these photo-dynamic resistant cells a technique has been proposed based on fractionated drug administration of diluted photosensitizer, keeping the net concentration (5 mg/kg) constant, and subsequently varying drug light interval (DLI). Flourescence measurements were made for the presence of photosensitizer in a tissue. For qualitative analysis both histological and morphological studies were made. Although preliminary aim of this approach was not achieved but there were some interesting observation made i.e. for higher dilution of photosensitizer there was a sharp boundary between necrotic and normal portion of tissue. An increase in the absorption coefficient (alpha) from 2.7 -> 2.9 was observed as photosensitizer was diluted while the corresponding threshold dose (D (th)) persistently decreases from (0.10 -> 0.02) J/cm(2) when irradiated with a 635 nm laser fluence of 150 J/cm(2).; higher education commission HEC Pakistan; higher education commission HEC Pakistan

"Correlação entre bioquímica celular e necrose tecidual em regimes de fracionamento de dose de luz em terapia fotodinâmica"; Correlation between cellular biochemistry and tecidual necrosis in light fractionation on photodynamic tehrapy

Bonini, Daniel
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 30/06/2006 PT
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Terapia fotodinâmica (TFD) é uma modalidade terapêutica pouco invasiva e sem efeitos térmicos aprovada para o tratamento de doenças neoplásicas e vasculares proliferativas, capaz de produzir necrose tecidual seletiva através de administração de um fármaco fotossensibilizador seguido da aplicação de luz em comprimento de onda adequado. Na presença de luz o fotossensibilizador passa à forma ativada, e na presença de oxigênio molecular presente nas células, produz espécies reativas de oxigênio e oxigênio singleto que induzem as células alteradas à morte. O melhor entendimento dos mecanismos e da resposta celular à TFD, a disponibilidade de fontes de luz mais baratas, confiáveis e de fácil manuseio, bem como bons resultados em pesquisa clínica, dão credibilidade à técnica e a sua difusão na prática clínica. Estudos recentes em dosimetria têm mostrado melhores resultados terapêuticos com o fracionamento da dose de luz uma vez que permite a reoxigenação dos tecidos durante o período em que esse não está sendo iluminado. Neste estudo, investigou-se o dano tecidual (profundidade de necrose) e os danos celulares, especificamente na mitocôndria (estado 3, estado 4, taxa do controle respiratório, relação de ADP/O...

Avaliação da viabilidade da quimiluminescência como fonte de luz em terapia fotodinâmica para controle microbiano.; Evaluation of the viability of the chemiluminescence as a PDT light source for microbial control

Ferraz, Ruy Carvalho Mattosinho de Castro
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 04/02/2010 PT
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A terapia fotodinâmica é a combinação do agente fotossensibilizador, da fonte de luz e do oxigênio que pode resultar na oxidação de biomoléculas e gerar danos celulares. Esta técnica é aplicada em diversas situações, desde o controle microbiológico até o tratamento de câncer. A maioria dos estudos utiliza as fontes de luz tradicionais, ou seja, lasers, sistemas à LED e lâmpadas. No entanto, poucos são os estudos que se concentram em propostas de fonte de luz alternativas. Iluminação portátil, flexível e independente de energia elétrica são características de grande interesse, principalmente, aos países em desenvolvimento no qual há uma grande parcela da população não assistida por hospitais de referência, além de cidades que não possuem o fornecimento de energia elétrica. Neste estudo, foi avaliada a viabilidade do uso, in vitro, da quimiluminescência como uma fonte de luz para a terapia fotodinâmica, induzindo a redução microbiana de Staphylococcus aureus. A quimiluminescência é uma reação química onde por meio da mistura de reagentes líquidos ocorre a emissão de luz sem a necessidade de qualquer ativação externa. Previamente aos estudos da aplicação terapia fotodinâmica in vitro, foram avaliadas diversas reações de quimiluminescência no intuito de estabelecer as características mais viáveis ao efeito fotodinâmico. Através de um modelo similar a teoria de Förster...

Estudo da distribuição de doses limiares em TFD para um modelo de cultura tridimensional de células obtido pelo método de levitação magnética; Study of the threshold doses distribution in PDT using the three-dimensional cell cultures obtained by the method of magnetic levitation

Sabino, Luis Gustavo
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 21/10/2014 PT
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Um conceito central na dosimetria da terapia fotodinâmica (TFD) é o limiar de dose (Dth do inglês threshold dose). O Dth é definido como a quantidade mínima de luz que deve ser absorvida pelas moléculas de fotossensibilizador (FS) dentro das células malignas a serem tratadas para que ocorra a morte celular por necrose ou apoptose. Os resultados do estudo da captação de FS por células Hep G2 demonstraram que uma população celular de linhagem, cultivada em monocamada, apresenta captação de Photogem (PG) heterogênea, ou seja, algumas células têm maior capacidade de captar moléculas de PG, outras células captam o PG em menor quantidade. A captação heterogênea de PG pode ser a causa para fenômenos de seleção de células mais resistentes à TFD. É razoável supor que as subpopulações celulares de uma mesma massa de células malignas possam apresentar diferentes valores de Dth. Definiu-se uma função de distribuição das doses limiares (g()) como uma função de distribuição gaussiana, e para a sua parametrização desenvolveu-se um método para o cultivo in vitro de culturas tridimensionais (culturas 3D), mais fidedignas ao tecido neoplásico maligno que as culturas tradicionais. Utilizando-se o método de levitação magnética (MLM) e o método de impressão magnética (MIM) para a dosimetria da TFD...

Photodynamic antimicrobial chemotherapy (PACT) for the treatment of malaria, leishmaniasis and trypanosomiasis

Baptista,M.S.; Wainwright,M.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 EN
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A photodynamic effect occurs when photosensitiser molecules absorb light and dissipate the absorbed energy by transferring it to biological acceptors (usually oxygen), generating an excess of reactive species that are able to force cells into death pathways. Several tropical diseases present physiopathological aspects that are accessible to the application of a photosensitiser and local illumination. In addition, disease may be transmitted through infected blood donations, and many of the aetiological agents associated with tropical diseases have been shown to be susceptible to the photodynamic approach. However, there has been no systematic investigation of the application of photoantimicrobial agents in the various presentations, whether to human disease or to the disinfection of blood products or even as photo-insecticides. We aim in this review to report the advances in the photoantimicrobial approach that are beneficial to the field of anti-parasite therapy and also have the potential to facilitate the development of low-cost/high-efficiency protocols for underserved populations.

Photodynamic therapy of the normal rat stomach: a comparative study between di-sulphonated aluminium phthalocyanine and 5-aminolaevulinic acid.

Loh, C. S.; Bedwell, J.; MacRobert, A. J.; Krasner, N.; Phillips, D.; Bown, S. G.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1992 EN
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Dysplasia in the upper gastrointestinal tract carries a risk of invasive malignant change. Surgical excision of the affected organ is the only treatment available. Photodynamic therapy has been shown to be promising in the treatment of early and superficial tumours and may be useful for the ablation of dysplastic mucosa. Because of the diffuse nature of the disease, such treatment would necessarily involve destruction of large areas of mucosa and it is desirable to confine its effect to the mucosa in order that safe healing can take place. By means of photometric fluorescence microscopy, we have studied the pattern of photosensitisation in the normal rat stomach using di-sulphonated aluminium phthalocyanine (AlS2Pc) and 5-aminolaevulinic acid (ALA) as photosensitisizers. AlS2Pc resulted in a panmural photosensitisation of the gastric wall with the highest level encountered in the submucosa. The mucosa and muscularis propria were sensitised to equal extent. Following light exposure, a full thickness damage resulted. ALA is a natural porphyrin precursor and exogenous administration gave rise to accumulation of protoporphyrin IX (PPIX) in the cells. The resultant pattern of photosensitisation was predominantly mucosal and its photodynamic effect was essentially confined to the mucosa. ALA produced a selective photosensitisation of the gastric mucosa for its photodynamic ablation with sparing the underlying tissue layers.

Efficient Photodynamic Therapy against Gram-Positive and Gram-Negative Bacteria Using THPTS, a Cationic Photosensitizer Excited by Infrared Wavelength

Schastak, Stanislaw; Ziganshyna, Svitlana; Gitter, Burkhard; Wiedemann, Peter; Claudepierre, Thomas
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 20/07/2010 EN
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The worldwide rise in the rates of antibiotic resistance of bacteria underlines the need for alternative antibacterial agents. A promising approach to kill antibiotic-resistant bacteria uses light in combination with a photosensitizer to induce a phototoxic reaction. Concentrations of 1, 10 and 100µM of tetrahydroporphyrin-tetratosylat (THPTS) and different incubation times (30, 90 and 180min) were used to measure photodynamic efficiency against two Gram-positive strains of S.aureus (MSSA and MRSA), and two Gram-negative strains of E.coli and P.aeruginosa. We found that phototoxicity of the drug is independent of the antibiotic resistance pattern when incubated in PBS for the investigated strains. Also, an incubation with 100µM THPTS followed by illumination, yielded a 6lg (≥99.999%) decrease in the viable numbers of all bacteria strains tested, indicating that the THPTS drug has a high degree of photodynamic inactivation. We then modulated incubation time, photosensitizer concentration and monitored the effect of serum on the THPTS activity. In doing so, we established the conditions to obtain the strongest bactericidal effect. Our results suggest that this new and highly pure synthetic compound should improve the efficiency of photodynamic therapy against multiresistant bacteria and has a significant potential for clinical applications in the treatment of nosocomial infections.

Nanoscintillator Conjugates as Photodynamic Therapy-Based Radiosensitizers: Calculation of Required Physical Parameters

Morgan, Nicole Y.; Kramer-Marek, Gabriela; Smith, Paul D.; Camphausen, Kevin; Capala, Jacek
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/2009 EN
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The recent demonstration of nanoscale scintillators has led to interest in the combination of radiation and photodynamic therapy. In this model, scintillating nanoparticles conjugated to photosensitizers and molecular targeting agents would enhance the targeting and improve the efficacy of radiotherapy and extend the application of photodynamic therapy to deeply seated tumors. In this study, we calculated the physical parameters required for these nanoparticle conjugates to deliver cytotoxic levels of singlet oxygen at therapeutic radiation doses, drawing on the published literature from several disparate fields. Although uncertainties remain, it appears that the light yield of the nanoscintillators, the efficiency of energy transfer to the photosensitizers, and the cellular uptake of the nano-particles all need to be fairly well optimized to observe a cytotoxic effect. Even so, the efficacy of the combination therapy will likely be restricted to X-ray energies below 300 keV, which limits the application to brachytherapy.

Solitary giant neurofibroma of the neck subjected to photodynamic therapy: case study

Hamdoon, Zaid; Jerjes, Waseem; Al-Delayme, Raed; Hopper, Colin
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 06/06/2012 EN
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Photodynamic therapy (PDT) - the fourth modality - has been successfully used in the management of early and advanced pathologies of the head and neck. We studied the effect of this modality on a giant solitary neurofibroma of the neck. A 70-year-old Caucasian female presented with left neck pain and disfigurement associated with slight shortness of breath and dysphagia. Examination revealed a large mass in the neck with no neurovascular compromise. Magnetic resonance imaging (MRI) reported a heterogeneously enhancing mass extending from the left angle of the mandible to the base of the neck. A core biopsy was performed and histopathological examination revealed a disorganised array of peripheral nerve fascicles. The patient elected to receive photodynamic therapy as the primary intervention. The multi-disciplinary meeting approved the treatment plan. The photosensitizing agent was mTHPC (0.15 mg/kg), which was systemically administered 96-hours prior to ultrasound (US)-guided light delivery to the mass, which was undertaken under general anaesthesia. Recovery was uneventful.Post-PDT follow-up showed that the patient’s pain, dysphagia and shortness of breath issues had improved. The disfigurement of the neck caused by the mass was no longer a problem. Three months post-PDT...

Nanoparticle-mediated combination chemotherapy and photodynamic therapy overcomes tumor drug resistance

Khdair, Ayman; Chen, Di; Patil, Yogesh; Ma, Linan; Dou, Q. Ping; Shekhar, Malathy P.V.; Panyam, Jayanth
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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Tumor drug resistance significantly limits the success of chemotherapy in the clinic. Tumor cells utilize multiple mechanisms to prevent the accumulation of anticancer drugs at their intracellular site of action. In this study, we investigated the anticancer efficacy of doxorubicin in combination with photodynamic therapy using methylene blue in a drug-resistant mouse tumor model. Surfactant-polymer hybrid nanoparticles formulated using an anionic surfactant, Aerosol-OT™ (AOT), and a naturally occurring polysaccharide polymer, sodium alginate, were used for synchronized delivery of the two drugs. Balb/c mice bearing syngeneic JC tumors (mammary adenocarcinoma) were used as a drug-resistant tumor model. Nanoparticle-mediated combination therapy significantly inhibited tumor growth and improved animal survival. Nanoparticle-mediated combination treatment resulted in enhanced tumor accumulation of both doxorubicin and methylene blue, significant inhibition of tumor cell proliferation, and increased induction of apoptosis. These data suggest that nanoparticle-mediated combination chemotherapy and photodynamic therapy using doxorubicin and methylene blue has significant therapeutic potential against drug-resistant tumors.

Mechanisms in photodynamic therapy: part two—cellular signaling, cell metabolism and modes of cell death

Castano, Ana P.; Demidova, Tatiana N.; Hamblin, Michael R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/2005 EN
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Photodynamic therapy (PDT) has been known for over a hundred years, but is only now becoming widely used. Originally developed as a tumor therapy, some of its most successful applications are for non-malignant disease. In the second of a series of three reviews, we will discuss the mechanisms that operate in PDT on a cellular level. In Part I [Castano AP, Demidova TN, Hamblin MR. Mechanism in photodynamic therapy: part one—photosensitizers, photochemistry and cellular localization. Photodiagn Photodyn Ther 2004;1:279–93] it was shown that one of the most important factors governing the outcome of PDT, is how the photosensitizer (PS) interacts with cells in the target tissue or tumor, and the key aspect of this interaction is the subcellular localization of the PS. PS can localize in mitochondria, lysosomes, endoplasmic reticulum, Golgi apparatus and plasma membranes. An explosion of investigation and explorations in the field of cell biology have elucidated many of the pathways that mammalian cells undergo when PS are delivered in tissue culture and subsequently illuminated. There is an acute stress response leading to changes in calcium and lipid metabolism and production of cytokines and stress proteins. Enzymes particularly...

Calreticulin as Cancer Treatment Adjuvant: Combination with Photodynamic Therapy and Photodynamic Therapy-Generated Vaccines

Korbelik, Mladen; Banáth, Judit; Saw, Kyi Min; Zhang, Wei; Čiplys, Evaldas
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 03/02/2015 EN
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Calreticulin is recognized as one of the pivotal damage-associated molecular pattern molecules alerting the host of the presence of distressed cells. In this role, calreticulin becomes exposed on the surface of tumor cells treated by several types of cancer therapy including photodynamic therapy (PDT). The goal of the present study was to examine the potential of externally added calreticulin for augmenting antitumor effect mediated by PDT. Recombinant calreticulin was found to bind to mouse SCCVII tumor cells treated by PDT. Compared to the outcome with PDT alone, cure rates of SCCVII tumors grown in immunocompetent C3H/HeN mice were elevated when calreticulin (0.4 mg/mouse) was injected peritumorally immediately after PDT. Such therapeutic gain with PDT plus calreticulin combination was not obtained with SCCVII tumors growing in immunodeficient NOD-scid mice. In PDT-vaccine protocol, where PDT-treated SCCVII cells are used for vaccination of SCCVII tumor-bearing mice, adding recombinant calreticulin to cells before their injection produced improved therapeutic effect. The expression of calreticulin gene was reduced in PDT-treated cells, while no changes were observed with the expression of this gene in tumor, liver, and spleen tissues in PDT-vaccine-treated mice. These findings reveal that externally added recombinant calreticulin can boost antitumor response elicited by PDT or PDT-generated vaccines...

Dual imaging-guided photothermal/photodynamic therapy using micelles

Guo, Miao; Mao, Huajian; Li, Yanli; Zhu, Aijun; He, Hui; Yang, Hong; Wang, Yangyun; Tian, Xin; Ge, Cuicui; Peng, Qiaoli; Wang, Xiaoyong; Yang, Xiangliang; Chen, Xiaoyuan; Liu, Gang; Chen, Huabing
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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We report a type of photosensitizer (PS)-loaded micelles integrating cyanine dye as potential theranostic micelles for precise anatomical tumor localization via dual photoacoustic (PA)/near-infrared fluorescent (NIRF) imaging modalities, and simultaneously superior cancer therapy via sequential synergistic photothermal therapy (PTT)/photodynamic therapy (PDT). The micelles exhibit enhanced photostability, cell internalization and tumor accumulation. The dual NIRF/PA imaging modalities of the micelles cause the high imaging contrast and spatial resolution of tumors, which provide precise anatomical localization of the tumor and its inner vasculature for guiding PTT/PDT treatments. Moreover, the micelles can generate severe photothermal damage on cancer cells and destabilization of the lysosomes upon PTT photo-irradiation, which subsequently facilitate synergistic photodynamic injury via PS under PDT treatment. The sequential treatments of PTT/PDT trigger the enhanced cytoplasmic delivery of PS, which contributes to the synergistic anticancer efficacy of PS. Our strategy provides a dual-modal cancer imaging with high imaging contrast and spatial resolution, and subsequent therapeutic synergy of PTT/PDT for potential multimodal theranostic application.

Effect of gold nanoparticles in the local heating of skin tumors induced by phototherapy

Salas García, Irene; Fanjul Vélez, Félix; Ortega Quijano, Noé; Lavín Castanedo, Ángela; Mingo Ortega, Patricia; López Escobar, María; Arce Diego, José Luis
Fonte: SPIE Society of Photo-Optical Instrumentation Engineers-; The Optical Society (OSA) Publicador: SPIE Society of Photo-Optical Instrumentation Engineers-; The Optical Society (OSA)
Tipo: info:eu-repo/semantics/conferenceObject; publishedVersion
ENG
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During optical therapies, several types of interaction between the optical radiation and the target tissue can occur. The application of different power densities and the variation of the exposure time can cause from photochemical reactions to photodisruption. Photothermal therapy (PTT) is based in the thermal interactions, where the biological injury is provoked by a given increase of their temperature during the exposition to the optical source. Another treatment option very extended in several clinical fields due to its promising results is Photodynamic Therapy. This treatment modality is based in photochemical reactions where it is also required oxygen and the administration of a photosensitive substance known as photosensitizer. The use of nanotechnology in optical therapeutic techniques, constitutes a novel promising treatment strategy. Specifically, gold nanoparticles can improve different issues related to the transport of photosensitizers or the light energy absorption and the subsequent heat generation. This work focuses in the effects that can produce the use of gold nanoparticles in Photothermal and Photodynamic Therapies applied to skin diseases commonly treated by means of these techniques. We present a thermal model that permits to calculate the temperature distribution in different kinds of pathological dermatological tissues depending on the optical power provided by the optical source. The results obtained permit to compare the thermal injury produced depending on not only the provided power but also the type of pathology and the incorporation or not of gold nanoparticles in the target tissue.

The association of fractional CO2 laser 10.600nm and photodynamic therapy in the treatment of onychomycosis

Oliveira,Guilherme Bueno de; Antonio,João Roberto; Antonio,Carlos Roberto; Tomé,Fernanda Alves
Fonte: Sociedade Brasileira de Dermatologia Publicador: Sociedade Brasileira de Dermatologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2015 EN
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AbstractBACKGROUND:Onychomycosis is a fungal infection of the nails caused in most cases by dermatophytes Trichophyton rubrum and Trichophyton mentagrophytes. Despite numerous available antifungal drugs for therapy of this infection, the cure rate is low, with high rates of relapse after treatment and side effects.OBJECTIVES:To present a new option for the treatment of onychomycosis, in search of a more effective and rapid method than conventional ones.METHODS:Patients underwent two sessions of CO2 fractional laser 10.600nm associated with photodynamic therapy. Mycological and digital photography were performed before and after the treatment.RESULTS:McNemar test with continuity correction and degrees of freedom = 1: for clinical cure rate, 13.06, with p=0.00005; for mycological cure, 17.05, with p=0.00005; 72% felt fully satisfied with the procedure.CONCLUSIONS:The use of fractional CO2 laser 10.600nm associated with photodynamic therapy can be effective in the treatment of onychomycosis, decreasing the risk of systemic lesions that may be triggered with prolonged use of oral antifungals.

Local clinical phototreatment of herpes infection in Sao Paulo

Tardivo, Joao Paulo; Wainwright, Mark; Baptista, Mauricio da Silva
Fonte: ELSEVIER SCIENCE BV; AMSTERDAM Publicador: ELSEVIER SCIENCE BV; AMSTERDAM
Tipo: Artigo de Revista Científica
ENG
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The clinical use of topical photodynamic therapy in herpes simplex lesions in Sao Paulo is presented and discussed. Although previous attempts utilising this type of approach in the USA were discontinued in the early 1970s due to several presentations of post-treatment Bowen's disease, none of the cases from the clinic presented here have displayed any complications on follow-up. In addition, lesion recrudescence periods are generally much longer than with conventional approaches. This is thought to be due to improvements in the treatment protocol, viz, use of the non-toxic photosensitisers methylene blue and Hypericum perforatum extract in place of proflavine and neutral red in the original trials, differences in photosensitisation pathway and illumination of the treatment site with red rather than fluorescent/UV light. Post-treatment cosmesis is also excellent. (C) 2012 Elsevier B.V. All rights reserved.

Stratum corneum lipids liposomes for the topical delivery of 5-aminolevulinic acid in photodynamic therapy of skin cancer: preparation and in vitro permeation study

Pierre, Maria ; Tedesco, Antônio C; Marchetti, Juliana M; Bentley, M Vitória LB
Fonte: Biblioteca Digital da Produção Intelectual da USP Publicador: Biblioteca Digital da Produção Intelectual da USP
Tipo: Artigo de Revista Científica
ENG
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Abstract Background Photodynamic therapy (PDT) using 5-aminolevulinic acid (5-ALA) is a skin cancer therapy that still has limitations due to the low penetration of this drug into the skin. We have proposed in this work a delivery system for 5-ALA based on liposomes having lipid composition similar to the mammalian stratum corneum (SCLLs) in order to optimize its skin delivery in Photodynamic Therapy (PDT) of skin cancers. Methods SCLLs were obtained by reverse phase evaporation technique and size distribution of the vesicles was determinated by photon correlation spectroscopy. In vitro permeation profile was characterized using hairless mouse skin mounted in modified Franz diffusion cell. Results Size exclusion chromatography on gel filtration confirmed vesicle formation. SCLLs obtained by presented a degree of encapsulation of 5-ALA around 5.7%. A distribution of vesicle size centering at around 500 nm and 400 nm respectively for SCLLs and SCLLs containing 5-ALA was found. In vitro 5-ALA permeation study showed that SCLLs preparations presented higher skin retention significantly (p < 0.05) on the epidermis without SC + dermis...

Clinical assessment of the efficacy of photodynamic therapy in the treatment of oral lichen planus

Sobaniec, Stefan; Bernaczyk, Piotr; Pietruski, Jan; Cholewa, Magdalena; Skurska, Anna; Dolińska, Ewa; Duraj, Ewa; Tokajuk, Grażyna; Paniczko, Agnieszka; Olszewska, Ewa; Pietruska, Małgorzata
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
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The study objective was clinical assessment of the efficacy of photodynamic therapy (PDT) in the treatment of oral lichen planus (OLP). There were 23 patients aged 31–82 included in the study with oral lichen planus diagnosed clinically and histopathologically. In all patients photodynamic therapy was performed with the use of chlorin e6 (Photolon®), containing 20 % chlorin e6 and 10 % dimethyl sulfoxide as a photosensitizer. PDT was performed using a semiconductor laser, with power up to 300 mW and a wavelength of 660 nm. A series of illumination sessions was conducted with the use of superficial light energy density of 90 J/cm2. Changes of lesion size were monitored at one, two, five, and ten PDT appointments from the series of ten according to the authors' own method. The sizes of clinical OLP lesions exposed to PDT were reduced significantly (on average by 55 %). The best effects were observed for the lesions on the lining mucosa (57.6 %). The therapy was statistically significantly less effective when masticatory mucosa was affected (reduction, 30.0 %). Due to substantial efficacy and noninvasiveness, PDT can be useful in the treatment of OLP lesions.

Synthesis and Characterization of Chitosan-Coated Near-Infrared (NIR) Layered Double Hydroxide-Indocyanine Green Nanocomposites for Potential Applications in Photodynamic Therapy

Wei, Pei-Ru; Kuthati, Yaswanth; Kankala, Ranjith Kumar; Lee, Chia-Hung
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 01/09/2015 EN
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We designed a study for photodynamic therapy (PDT) using chitosan coated Mg–Al layered double hydroxide (LDH) nanoparticles as the delivery system. A Food and Drug Administration (FDA) approved near-infrared (NIR) fluorescent dye, indocyanine green (ICG) with photoactive properties was intercalated into amine modified LDH interlayers by ion-exchange. The efficient positively charged polymer (chitosan (CS)) coating was achieved by the cross linkage using surface amine groups modified on the LDH nanoparticle surface with glutaraldehyde as a spacer. The unique hybridization of organic-inorganic nanocomposites rendered more effective and successful photodynamic therapy due to the photosensitizer stabilization in the interlayer of LDH, which prevents the leaching and metabolization of the photosensitizer in the physiological conditions. The results indicated that the polymer coating and the number of polymer coats have a significant impact on the photo-toxicity of the nano-composites. The double layer chitosan coated LDH–NH2–ICG nanoparticles exhibited enhanced photo therapeutic effect compared with uncoated LDH–NH2–ICG and single layer chitosan-coated LDH–NH2–ICG due to the enhanced protection to photosensitizers against photo and thermal degradations. This new class of organic-inorganic hybrid nanocomposites can potentially serve as a platform for future non-invasive cancer diagnosis and therapy.