RESUMO
OBJECTIVE: Photodynamic therapy (PDT) is an effective method for Candida spp. inactivation in vitro and in vivo, but as yet, no clinical trial has been conducted. This report describes 5 cases of denture stomatitis (DS) treated with PDT. STUDY DESIGN: Five subjects with clinical and microbiologic diagnosis of DS were submitted to 6 sessions of PDT 3 times a week for 15 days. In each session, patients' dentures and palates were sprayed with 500 mg/L Photogem, and, after 30 minutes of incubation, irradiated by light-emitting diode light source at 455 nm (37.5 and 122 J/cm(2), respectively). Cultures of Candida spp. from dentures and palates and standard photographs of the palates were taken at baseline (day 0), at the end of the treatment (day 15), and at follow-up time intervals (days 30 and 60). RESULTS: Four patients showed clinical resolution of DS (no inflammation) after PDT sessions, and only 1 subject demonstrated reduction in palatal inflammation. Recurrence of DS was observed in 2 patients during the follow-up period. CONCLUSIONS: PDT appears to be an alternative treatment for DS.
Assuntos
Candida/efeitos da radiação , Prótese Total Superior/efeitos adversos , Fotorradiação com Hematoporfirina/métodos , Estomatite sob Prótese/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Prótese Total Superior/microbiologia , Feminino , Seguimentos , Hematoporfirinas/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade , Palato/microbiologia , Palato/efeitos da radiação , Fármacos Fotossensibilizantes/uso terapêutico , Estomatite sob Prótese/microbiologia , Resultado do TratamentoRESUMO
Photodynamic therapy (PDT) using a haematoporphyrin derivative (Photogem, General Physics Institute and clustes Ltda) as photosensitizer and light emitting diodes (LEDs) as the light source was evaluated in 12 cats with cutaneous squamous cell carcinoma. Lesions were illuminated with LEDs, (300 J/cm for 30 min) 24 h after the administration of the photosensitizer. Clinical responses were classified as complete disappearance of the tumour with total re-epithelialization; partial response (a reduction greater than 50%); and no response (less than 50% reduction). Tumours localized to the pinna treated with one (n = 3) or two (n = 4) applications of PDT yielded no response. Highly invasive tumours of the nose and nasal planum also showed no response, after two treatments (n = 2). A combination of PDT and surgery was performed in three cases. Two cats showed partial response and one complete response with one application of therapy 30 days after nasal surgery. Small and noninfiltrative lesions (n = 3) of the nasal planum showed a PR with one application (n = 2) and a CR with two applications (n = 1). This study shows that PDT using Photogem and LEDs can provide local control of low-grade feline squamous cell carcinoma. The addition of PDT to surgery in more invasive cases may help prevent recurrence.
Assuntos
Carcinoma de Células Escamosas/veterinária , Doenças do Gato/tratamento farmacológico , Fotorradiação com Hematoporfirina/veterinária , Neoplasias Cutâneas/veterinária , Animais , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/cirurgia , Doenças do Gato/cirurgia , Gatos , Terapia Combinada/veterinária , Feminino , Fotorradiação com Hematoporfirina/métodos , Masculino , Recidiva Local de Neoplasia/prevenção & controle , Recidiva Local de Neoplasia/veterinária , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/cirurgia , Resultado do TratamentoRESUMO
OBJECTIVE: The aim of this study was the evaluation of two different photosensitizers activated by red light emitted by light-emitting diodes (LEDs) in the decontamination of carious bovine dentin. MATERIALS AND METHODS: Fifteen bovine incisors were used to obtain dentin samples which were immersed in brain-heart infusion culture medium supplemented with 1% glucose, 2% sucrose, and 1% young primary culture of Lactobacillus acidophilus 10(8) CFU/mL and Streptococcus mutans 10(8) CFU/mL for caries induction. Three different concentrations of the Photogem solution, a hematoporphyrin derivative (1, 2, and 3 mg/mL) and two different concentrations of toluidine blue O (TBO), a basic dye (0.025 and 0.1 mg/mL) were used. To activate the photosensitizers two different light exposure times were used: 60 sec and 120 sec, corresponding respectively to the doses of 24 J/cm(2) and 48 J/cm(2). RESULTS: After counting the numbers of CFU per milligram of carious dentin, we observed that the use of LED energy in association with Photogem or TBO was effective for bacterial reduction in carious dentin, and that the greatest effect on S. mutans and L. acidophilus was obtained with TBO at 0.1 mg/mL and a dose of 48 J/cm(2). It was also observed that the overall toxicity of TBO was higher than that of Photogem, and that the phototoxicity of TBO was higher than that of Photogem. CONCLUSION: Based on our data we propose a mathematical model for the photodynamic effect when different photosensitizer concentrations and light doses are used.
Assuntos
Cárie Dentária/tratamento farmacológico , Dentina/efeitos dos fármacos , Dentina/microbiologia , Derivado da Hematoporfirina/administração & dosagem , Fármacos Fotossensibilizantes/administração & dosagem , Cloreto de Tolônio/administração & dosagem , Animais , Bovinos , Fotorradiação com Hematoporfirina , Lactobacillus acidophilus/efeitos dos fármacos , Modelos Biológicos , Fotoquimioterapia , Streptococcus mutans/efeitos dos fármacosRESUMO
In this study we investigated the pharmacokinetics of a hematoporphyrin derivative (Photogem) in Wistar rats using the fluorescence spectroscopy to evaluate the drug distribution in liver, kidney and skin tissues. The detection system is composed of a 532 nm exciting laser, a Y-type catheter for light delivery and collection, a monochromator and a computer for data acquisition. The analysis of the fluorescence spectra was based on the intensity of porphyrin emission bands from specific tissues of the investigated organ. A simple transport model is proposed to determine the accumulation and elimination times for each type of investigated tissue. The obtained results show the viability of the fluorescence spectroscopic technique for the drug concentration monitoring in different target tissues and related pharmacokinetics. These effects should be considered before any in vivo study of Photodynamic Therapy using Photogem.
Assuntos
Fotorradiação com Hematoporfirina/métodos , Hematoporfirinas/administração & dosagem , Hematoporfirinas/farmacocinética , Rim/metabolismo , Fígado/metabolismo , Pele/metabolismo , Espectrometria de Fluorescência/métodos , Animais , Injeções Intravenosas , Masculino , Taxa de Depuração Metabólica , Especificidade de Órgãos , Ratos , Ratos Wistar , Espectrometria de Fluorescência/instrumentação , Distribuição TecidualRESUMO
The major drawback of cancer chemotherapy is the development of multidrug-resistant (MDR) tumor cells, which are cross-resistant to a broad range of structurally and functionally unrelated agents, making it difficult to treat these tumors. In the last decade, a number of authors have studied the effects of photodynamic therapy (PDT), a combination of visible light with photosensitizing agents, on MDR cells. The results, although still inconclusive, have raised the possibility of treating MDR tumors by PDT. This review examines the growing literature concerning the responses of MDR cells to PDT, while stressing the need for the development of new photosensitizers that possess the necessary characteristics for the photodynamic treatment of this class of tumor.
Assuntos
Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Fotorradiação com Hematoporfirina , Neoplasias/tratamento farmacológico , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Animais , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Humanos , Fármacos Fotossensibilizantes/metabolismo , Fármacos Fotossensibilizantes/uso terapêutico , Porfirinas/metabolismo , Porfirinas/farmacologia , Porfirinas/uso terapêutico , Células Tumorais CultivadasRESUMO
A Terapia Fotodinâmica do Câncer (PDT) é baseada no envolvimento de três fatores, a saber: retençäo pelo tecido canceroso de um fotossensibilizador específico; iluminaçäo localizada da lesäo e ocorrência de oxigênio inicialmente no estado fundamental triplete. Na literatura científica sobre o assunto, encontravam-se vários trabalhos sobre a dosagem de fotossensibilizadores diversos e sobre a dosometria da radiaçäo visível capaz de provocar a terapia. O nível de oxigênio, por depender intrinsicamente do organismo tratado, tem sido tomado como um parâmetro constante na terapia e raramente estudado. No presente trabalho apresentamos pela primeira vez um desenvolvimento teórico que relaciona matematicamente o dano celular resultante do tratamento, com a variaçäo do aporte de oxigênio nas células cancerosas.
Assuntos
Animais , Ratos , Fotorradiação com Hematoporfirina/métodos , Fotoquimioterapia , OncologiaRESUMO
Revisou-se a literatura acerca da utilizaçäo da hematoporfirina associada à luz, no tratamento de tumores malignos. Foram apresentadas as hipóteses formuladas sobre o mecanismo de açäo desta associaçäo, assim como resumidos os diferentes métodos utilizados, seja em animais de experimentaçäo, seja no homem. Foram também expostos os resultados obtidos da literatura, efetuando-se os comentários sobre esta opçäo para o tratamento de neoplasias malignas