Search results for "Photosensitizing agent"
showing 10 items of 67 documents
Albumin-Folate Conjugates for Drug-targeting in Photodynamic Therapy.
2016
Photodynamic therapy (PDT) is based on the cytotoxicity of photosensitizers in the presence of light. Increased selectivity and effectivity of the treatment is expected if a specific uptake of the photosensitizers into the target cells, often tumor cells, can be achieved. An attractive transporter for that purpose is the folic acid receptor α (FRα), which is overexpressed on the surface of many tumor cells and mediates an endocytotic uptake. Here, we describe the synthesis and photobiological characterization of polar β-carboline derivatives as photosensitizers covalently linked to folate-tagged albumin as the carrier system. The particles were taken up by KB (human carcinoma) cells within …
Photosensitization of DNA by β-carbolines: Kinetic analysis and photoproduct characterization
2012
β-Carbolines (βCs) are a group of alkaloids present in many plants and animals. It has been suggested that these alkaloids participate in a variety of significant photosensitized processes. Despite their well-established natural occurrence, the main biological role of these alkaloids and the mechanisms involved are, to date, poorly understood. In the present work, we examined the capability of three important βCs (norharmane, harmane and harmine) and two of its derivatives (N-methyl-norharmane and N-methyl-harmane) to induce DNA damage upon UV-A excitation, correlating the type and extent of the damage with the photophysical characteristics and DNA binding properties of the compounds. The r…
A randomized, intraindividual, non-inferiority, Phase III study comparing daylight photodynamic therapy with BF-200 ALA gel and MAL cream for the tre…
2018
Abstract Background The most effective treatment modality for actinic keratosis (AK) is photodynamic therapy (PDT). Major obstacles of PDT are the need of a special illumination device and pain accompanying the illumination. These issues may be overcome by replacing an artificial high‐power light source with natural daylight for more extended illumination at lower light doses. Objective To determine whether BF‐200 ALA (a nanoemulsion gel containing 7.8% 5‐aminolaevulinic acid) is non‐inferior to MAL (a cream containing 16% methyl‐aminolaevulinate) in the treatment of mild‐to‐moderate AK with daylight PDT (dPDT). Non‐inferiority of the primary efficacy variable (total lesion clearance rate p…
Simulations of a Graphene Nanoflake as a Nanovector To Improve ZnPc Phototherapy Toxicity: From Vacuum to Cell Membrane
2017
International audience; We propose a new approach to improving photodynamic therapy (PDT) by transporting zinc phthalocyanine (ZnPc) in biological systems via a graphene nanoflake, to increase its targeting. Indeed, by means of time-dependent density functional theory simulations, we show that the ZnPc molecule in interaction with a graphene nanoflake preserves its optical properties not only in a vacuum but also in water. Moreover, molecular dynamic simulations demonstrate that the graphene nanoflake/ZnPc association, as a carrier, permits one to stabilize the ZnPc/graphene nanoflake system on the cellular membrane, which was not possible when using ZnPc alone. We finally conclude that the…
Photodynamic therapy of nodular basal cell carcinoma with multifiber contact light delivery.
2006
To overcome the limited treatment depth of superficial photodynamic therapy we investigate interstitial light delivery. In the present work the treatment light was delivered using a system in which three or six clear-cut fibers were placed in direct contact with the tumor area. This placement was thought to represent a step toward general purpose interstitial PDT. Twelve nodular basal cell carcinomas were treated employing delta-aminolevulinic acid and 635 nm laser irradiation. Fluorescence measurements were performed monitoring the buildup and subsequent bleaching of the produced sensitizer protoporphyrin IX. The treatment efficacy, judged at a 28-month follow-up, showed a 100% complete re…
Porphyrin and phthalocyanine photosensitizers designed for targeted photodynamic therapy of colorectal cancer
2020
Colorectal cancer is of particular concern due to its high mortality rate count. Recent investigations on targeted phototherapy involving novel photosensitizers and drug-delivery systems have provided promising results and realistic prospects for a successful medical treatment. New research trends have been focused particularly on development of advanced molecular systems offering effective photoactive species which could be selectively delivered directly into the affected cells. Porphyrins and phthalocyanines have been considered extremely attractive for this purpose due to their molecular versatility, excellent photochemical properties and multifunctional nature. In this review it has bee…
Intensified oxidative and nitrosative stress following combined ALA-based photodynamic therapy and local hyperthermia in rat tumors.
2003
Oxidative stress-related changes in tumors upon localized hyperthermia (HT), 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) and their combination (ALA+HT) were examined after the observation that the antitumor effects of ALA-PDT could be significantly enhanced upon simultaneous application of HT. Rats bearing s.c. DS-sarcomas (0.6–1.0 ml) on the hind foot dorsum were anesthetized and underwent one of the following treatments: (i) ALA-PDT (375 mg/kg 5-ALA i.v.); (ii) localized HT, 43°C for 60 min; (iii) combined ALA-PDT and HT [=ALA+HT]. Appropriate control experiments were also performed. After treatment, tumors were excised and rapidly frozen for later analysis of nitrosative s…
Modification of Structural and Luminescence Properties of Graphene Quantum Dots by Gamma Irradiation and Their Application in a Photodynamic Therapy
2015
Herein, the ability of gamma irradiation to enhance the photoluminescence properties of graphene quantum dots (GQDs) was investigated. Different doses of gamma-irradiation were used on GQDs to examine the way in which their structure and optical properties can be affected. The photoluminescence quantum yield was increased six times for the GQDs irradiated with high doses compared to the nonirradiated material. Both photoluminescence lifetime and values of optical band gap were increased with the dose of applied gamma irradiation. In addition, the exploitation of the gamma-irradiated GQDs as photosensitizers was examined by monitoring the production of singlet oxygen under UV illumination. T…
Long-Segment Early Squamous Cell Carcinoma of the Proximal Esophagus: Curative Treatment and Long-Term Follow-Up after 5-Aminolevulinic Acid (5-ALA)-…
2006
Photodynamic therapy (PDT) is an established treatment for the ablation of dysplastic Barrett's epithelium and early esophageal carcinoma, but no data have been published on curative 5-aminolevulinic acid (5-ALA)-PDT for long-segment early esophageal cancer with infiltration of the upper sphincter. We describe successful curative treatment of an unusual early long-segment squamous cell carcinoma (uT1a,N0) of the proximal esophagus (18 - 28 cm aborally), with three sessions of 5-ALA-PDT. Endoscopic and endosonographic follow-up macroscopically showed a complete remission of the tumor, proven by biopsy showing total histological ablation. After a follow-up period of 23 months, there has been …
Photodynamic therapy with verteporfin for juxtafoveal choroidal neovascularization in pathologic myopia: a long-term follow-up study.
2007
Purpose To assess the effect of verteporfin photodynamic therapy (PDT) in juxtafoveal choroidal neovascularization (CNV) secondary to pathologic myopia (PM). Design Prospective, open-label, consecutive, interventional case series. Methods We prospectively followed a series of 48 consecutive patients (49 eyes) with pathologic myopia (≥ 6 diopters) who received verteporfin PDT for juxtafoveal CNV. This population was divided into two groups based on age (group A ≤ 55 years old, group B >55 years old), in three subgroups based on CNV lesion size, and in three categories based on refractive error at baseline. Results The median follow-up was 32 months (range, 12 to 56 months). Visual acuity (VA…