Search results for "Photodynamic therapy"
showing 10 items of 94 documents
Interactions of amino acids with aluminum octacarboxyphthalocyanine hydroxide. Experimental and DFT studies
2017
The influence of albumin and amino acids (l-serine, glycine, l-histidine, l-tryptophan, l-cysteine) on the properties of aluminum octacarboxyphthalocyanine hydroxide (Al(OH)PcOC) was investigated in a phosphate buffer (pH 8.0). Particular attention was paid to the spectroscopic properties and photostability of Al(OH)PcOC. The effect of albumin or amino acids on the photodegradation of Al(OH)PcOC was examined in water using red light: 685 nm and daylight irradiation. Analysis of kinetic curves indicated that interaction with those molecules increases the photostability of Al(OH)PcOC. The molecular structure of Al(OH)PcOC complexes (in vacuum and in water) with axially or equatorially coordin…
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…
Photodynamic therapy with verteporfin for subfoveal choroidal neovascularization secondary to pathologic myopia: long-term study.
2006
Purpose: To assess the safety and effectiveness of photodynamic therapy (PDT) with verteporfin for subfoveal choroidal neovascularization (CNV) secondary to pathologic myopia (PM). Methods: Sixty-two patients (62 eyes) with PM underwent PDT according to the guidelines of the Verteporfin in Photodynamic Therapy Study. Clinical evaluations performed at all study visits included measurement of best-corrected Snellen visual acuity, slit-lamp biomicroscopy, and fundus fluorescein angiography. Patients were followed up at 1 month and 3 months after treatment and thereafter at 3-month intervals. Results: The final visual acuity of the study patients, after a median follow-up of 31 months, improved…
Invisible gastric carcinoma detected by random biopsy: long-term results after photodynamic therapy
2008
Background and study aims Gastric cancer diagnosed from routine gastric biopsies without any evidence of a visible lesion and negative repeated biopsies is an infrequent but serious clinical problem for which gastrectomy has usually been recommended, even if operative specimens do not show cancer either. We report on a series of 22 such patients undergoing long-term follow-up after attempted treatment with photodynamic therapy (PDT). Patients and methods 22 patients with invisible gastric cancer (IGC) who presented during a 10-year period (10 men, mean age 56 +/- 15 years) were prospectively included. Initial histopathological findings confirmed by second opinion included 10 well-differenti…
Halogen-containing BODIPY derivatives for photodynamic therapy
2019
Abstract Two iodinated (1 and 2) and two brominated (3 and 4) BODIPY-based photosensitizers are prepared and characterized using slightly modified synthetic procedures previously described. 1–4 present intense absorption bands in the 510–540 nm interval and very weak emissions due to the presence of halogen atoms in their structure. Irradiation of aqueous solutions of 1–4 with visible light (wavelength > 475 nm) induce the generation of singlet oxygen with quantum yields of ca. 0.62–0.66 for the photosensitizers containing iodine atoms (1 and 2) and of ca. 0.16–0.21 for the brominated counterparts (3 and 4). In vitro studies carried out with HeLa, SCC-13 and HaCaT cell lines and the four ph…
Direct subphthalocyanine conjugation to bombesin vs. indirect conjugation to its lipidic nanocarrier
2016
International audience; Bombesin (BBN) was covalently bound to graftable subphthalocyanine (SubPc) or to a cholesterol derivative, a component of a liposome that encapsulates non-graftable SubPc. The latter bioconjugation approach was suitable to address the stability of SubPc and was achieved by copper-free click-chemistry on the outer-face of the liposome. Liposomes were purified (FPLC) and then analyzed in size (outer diameter about 60 nm measured by DLS). In vitro binding studies allowed to determine the IC50 13.9 nM for one component of the liposome, cholesterol, conjugated to BBN. Hence, azido- (or alkynyl-) liposomes give fluorophores with no reactive functional group available on th…
Synthesis and In Vitro Evaluation of a Photosensitizer-BODIPY Derivative for Potential Photodynamic Therapy Applications
2015
A new photosensitizer (1) based on the 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) scaffold has been synthesized. 1 is water soluble and showed an intense absorption band at 490 nm (e=77600 cm-1M-1) and an emission at 514 nm. In vitro toxicity of 1 in the presence of light and in darkness has been studied with HeLa, HaCaT, MCF-7, and SCC-13 cell lines. Moreover, internalization studies of 1 in these cell lines were also performed. These results suggested that 1 is more toxic for SCC-13 and HeLa carcinoma cells than for the HaCaT noncancerous immortal human keratinocytes. Toxicity upon light irradiation was due to the formation of singlet oxygen and reactive oxygen species (ROS). Cel…
Tumor Hypoxia: Causative Factors, Compensatory Mechanisms, and Cellular Response
2004
Abstract Learning Objectives After completing this course, the reader will be able to: Explain the effect of hypoxia on resistance to treatment. Describe the causes of tumor hypoxia. Characterize cellular response to hypoxia. Access and take the CME test online and receive 1 hour of AMA PRA category 1 credit at CME.TheOncologist.com Hypoxia is a characteristic feature of locally advanced solid tumors resulting from an imbalance between oxygen (O2) supply and consumption. Major causative factors of tumor hypoxia are abnormal structure and function of the microvessels supplying the tumor, increased diffusion distances between the nutritive blood vessels and the tumor cells, and reduced O2 tra…
Site-Specific Dual-Labeling of a VHH with a Chelator and a Photosensitizer for Nuclear Imaging and Targeted Photodynamic Therapy of EGFR-Positive Tum…
2021
Simple Summary Variable domains of heavy chain only antibodies are small proteins that can be used for tumor imaging and therapy upon conjugation of functional groups. As frequently used random conjugation techniques can decrease binding to the target of interest, site-specific conjugation of these functional groups is preferred. Here, we optimized site-specific conjugation of both a chelator for binding of a radiometal and a photosensitizer to epidermal growth factor receptor (EGFR) binding VHH 7D12. We characterized this dual-labeled VHH for nuclear imaging and targeted photodynamic therapy of EGFR-expressing tumors. Abstract Variable domains of heavy chain only antibodies (VHHs) are valu…
Relation of early Photofrin uptake to photodynamically induced phototoxicity and changes of cell volume in different cell lines.
1994
For efficacy of photodynamic therapy, selective uptake and retention of photoactive substances has been postulated. Therefore, measurements were performed to find out whether the photosensitiser Photofrin® is taken up differently in malignant and non-malignant cells in vitro . In addition, the sensitivity of malignant cells and nonmalignant cells to photodynamic exposure was investigated, by quantifying viability and volume alterations of the cells. Bovine aortic endothelial cells, mouse fibroblasts and amelanotic hamster melanoma cells were suspended in a specially designed incubation chamber under controlled conditions (e.g. pH, p O 2 , p CO 2 and temperature). After establishing constant…