Photodynamic Therapy Procedure Research Articles

Photodynamic Therapy with Two Different Photosensitizers as a Supplement to Instrumentation/Irrigation Procedures in Promoting Intracanal Reduction of Enterococcus faecalis

Introduction This in vitro study aimed to investigate the antibacterial effects of photodynamic therapy (PDT) with methylene blue (MB) or toluidine blue (TB) (both at 15 μg/mL) as a supplement to instrumentation/irrigation of root canals experimentally contaminated with Enterococcus faecalis. Methods Seventy extracted teeth had their root canals contaminated with an endodontic strain of E. faecalis for 7 days, instrumented with nickel-titanium instruments and irrigated either with 2.5% NaOCl or with 0.85% NaCl, and then randomly distributed into four experimental groups: MB/NaOCl (PDT with MB and NaOCl as the irrigant), TB/NaOCl (PDT with TB and NaOCl as the irrigant), MB/NaCl (PDT with MB and NaCl as the irrigant), and TB/NaCl (PDT with TB and NaCl as the irrigant). For PDT, the photosensitizer remained in the canal for 2 minutes before exposed to red light emitted from a diode laser for 4 minutes. Samples were taken before and after instrumentation/irrigation and following the specific PDT procedure for each group, plated onto Mitis-salivarius agar and the colony forming units counted. Results Regardless of the irrigant used (NaOCl or NaCl), instrumentation significantly reduced bacterial counts in comparison to the baseline (p < 0.001). NaOCl as the irrigant was significantly more effective than NaCl, and this difference persisted after PDT, irrespective of the photosensitizer used (p < 0.05). PDT with either MB or TB did not significantly enhance disinfection after chemomechanical preparation using NaOCl as irrigant (p > 0.05). No significant differences were observed between the two photosensitizers (p > 0.05). Conclusion These in vitro results suggest that PDT with either MB or TB may not exert a significant supplemental effect to instrumentation/irrigation procedures with regard to intracanal disinfection. Further adjustments in the PDT protocol may be required to enhance predictability in bacterial elimination before clinical use is recommended.

Photodynamic activity of metalloporphyrins on human neuroblastoma cell line

Tetraphenyl and tetranitrophenyl base porphyrins were synthesized usingmicrowave irradiation technique. Their metallic complexes with copper, zinc, tin and lead were also synthesized by conventional methods. The lipophilicity of the well-characterized compounds was evaluated at 25 OC and in vitro photodynamic activity was analyzed with human neuroblastoma cell lines. The photosensitizing efficiency of the metalloporphyrins in photodynamic therapy (PDT) increases in the order of Cu>Pb>Zn>Sn. Among the well characterized porphyrins and their metallic derivatives, copper and lead complexes were found to show better photodynamic activity than zinc and tin porphyrins and this methodology can beused to demonstrate the PDT procedure in a laboratory experiment.

Photodynamic Therapy of Human Colorectal Carcinoma Cell Line

Colorectal cancer is one of the most common cancers in Europe and North America and it is the most common gastrointestinal carcinoma. The population in the Czech Republic has a higher incidence of colorectal carcinoma compared to other countries. Efforts are underway to develop better screening strategies and novel therapies to improve patient survival rates. Despite all efforts, colorectal cancer remains one of the leading causes of death from cancer. Photodynamic therapy (PDT) is an established modality for the treatment of various diseases. The PDT procedure involves the administration of a photosensitizer followed by illumination. The anti-tumor effects result from direct killing of malignant cells, shutting down of the tumor's vasculature, and the promotion of an immune response. In our experiment, we examined the effects of phototherapy with disulfonated hydroxyaluminum phthalocyanine (Al(OH)S2Pc) on the growth of colorectal carcinoma cells, in an effort to offer a new treatment modality for patients with this disease.

Multiple Components of Photodynamic Therapy Can Phosphorylate Akt†

A growing number of clinically relevant molecular and cellular responses are observed following photodynamic therapy (PDT). PDT-mediated oxidative stress and PDT-induced tissue hypoxia can elicit the transcriptional and/or translational expression of genes associated with cellular stress, inflammation, angiogenesis, immuno-modulation, apoptosis and signal transduction. One of the signaling molecules activated by oxidative stress is Akt/protein kinase B. Phosphorylation of Akt/protein kinase B activates this signaling molecule and induces a survival response in effected cells and tissue. We hypothesized that PDT using Photofrin (PH) as the photosensitizer could also induce increased levels of Akt phosphorylation. Results from our initial set of experiments demonstrated that in vitro and in vivo PDT treatments induced Akt phosphorylation. Interestingly, incubation of mouse and human breast cancer cells with the porphyrin-based photosensitizer, PH, increased the expression of Akt phosphorylation in the absence of light. Exposure of the corresponding mouse and human-derived breast cancer tumors growing in mice to 630 nm light in the absence of PH administration also induced Akt phosphorylation. These results demonstrate that individual components of the PDT process, photosensitizer alone and light alone, as well as the complete PDT procedure can activate the Akt signaling pathway.

413 Intérêt d’une injection intravitréenne de triamcinolone versus intra vitréenne de Bevacizumab combinée à la photothérapie dynamique dans le cas des décollements séreux de l’épithélium pigmentaire compliquant une DMLA exsudative

But To compare the short term effectiveness and safety of Intravitreal Triamcinolone Acetonide (IVTA) versus Intravitreal Bevacizumab in the treatment of Pigment Epithelial Detachment (PED) associated with Choroidal Neovascularization secondary to Age Related Macular Degeneration, in patients whom Photodynamic therapy (PDT) with verteporfine had been estimated to increase high risk of pigment epithelial tears. Materials and Methods We prospectively included 29 eyes of 29 patients divided in 2 groups. After appropriate informed consent, patients of group I had an intravitreal injection of 1.25mg/0.05ml of Bevacizumab. Patients of group II received 4mg/0.1ml of triamcinolone acetonide. For the follow up, ETDRS, stereo fundus examination and OCT imaging were performed at week 2 in all cases. Local and systemic adverses effects were evaluated. Patients who had at least 20/200 VA and a partial or completed PED regression were treated with PDT. Results At week 2, group I showed greater mean gain in VA. OCT imaging revealed regression of macula edema and SNRD in all cases as in group II, but less significative regression of the size of the PED. In group I, 5 cases (45.5 %) had no change of the PED. We postponed the PDT procedure in these cases. Three months after PDT, no case of retinal tear was reported. In group I, No endophthalmitis, cataract or elevated IOP were reported, neither systemic adverses effects. In group II, 2 cases of transient IOP elevation (11%) and 3 cataracts in phakic patients were reported. Conclusion The short term anatomical changes observed in our study suggest that intravitreal triamcinolone acetonide is a better effective method to reduce PED in ARMD than intravitreal Bevacizumab in spite of local adverses effects. Which consecutively allows PDT However, further studies are needed to confirm these findings.

Comparative benefit of two thermal spring waters after photodynamic therapy procedure

Photodynamic therapy (PDT) is commonly used to treat actinic keratoses, superficial cutaneous carcinoma, photodamage, and/or acne. The aim of this study was to compare the usefulness of Avène thermal spring water (ATSW), a low mineral content spring water, to a high mineral content spring water. We evaluated post-PDT clinical symptoms and findings when used as an adjunctive therapy in postprocedure skin care. A double-blind monocentric comparative study was conducted on 25 patients suffering from either vulgaris acne or photodamage with or without actinic keratoses. The patients were treated with 5-aminolevulinic acid (5-ALA) activated with an intense pulsed light and/or blue light source. Patients were randomized so that 12 patients treated their faces with ATSW and 13 were treated with a comparative water spray. Clinical signs were evaluated by the investigator at day 0, before and 15 min after the first spraying, at days 2, 4, and 7, and each day from day 0 to day 6 by patients. Clinical signs (erythema, stinging, pruritus, pain, and tightening) were evaluated by the use of a 4-point grading scale. The intragroup analysis showed that pain was significantly reduced by ATSW spraying at days 2, 4, and 7. The evaluation by patients showed that only ATSW alleviates pain from day 3 to day 6. The between-group analysis revealed that pruritus was significantly reduced by ATSW at day 7. Erythema, stinging, and tightening were not significantly reduced by both waters. Patients wished to continue using ATSW in 83% of cases. This comparative clinical trial demonstrates that ATSW, a low mineral content spring water, can be useful after ALA-PDT in reducing postprocedure cutaneous inflammation and patient discomfort better than a high mineral content spring water.

Fluorescence Monitoring of a Topically Applied Liposomal Temoporfin Formulation and Photodynamic Therapy of Nonpigmented Skin Malignancies

Meso-tetra(hydroxyphenyl)chlorin (mTHPC) (INN: Temoporfin) is a potent photodynamically active substance in clinical use today. Usually, the substance is given systemically and a known drawback with this administration route is a prolonged skin light sensitization. For the first time to our knowledge, a liposomal Temoporfin gel formulation for topical application was studied in connection with photodynamic therapy (PDT) of nonpigmented skin malignancies in humans. Intervals of 4 hr between drug administration and light irradiation were used. Sensitizer distribution within tumor and surrounding normal skin was investigated by means of point monitoring and imaging fluorescence spectroscopy before, during, and after PDT, showing high tumor selectivity. Furthermore, the bleaching of Temoporfin was studied during the PDT procedure by monitoring the fluorescence following excitation by using a therapeutic light. A 30-35% light-induced photometabolization was shown. No pain occurred during or after treatment. It was also observed that the treated area did not show any swollen tissue or reddening, as is often seen in PDT using topical delta-aminolevulinic acid. On controlling the patients one week after treatment, healing progress was observed in several patients and no complications were registered.

Synthetic porphyrins in experimental photodynamic therapy induce a different antitumoral effect

The aim of the study was to investigate the influence of discrete structural differences in synthetic porphyrins on the antineoplastic effect induced in myelocitic cell line K562 after experimental photodynamic therapy procedure. For this study, we used 5,10,15,20-tetra(1-naphthyl)porphyrin, 5,10,15,20-tetra(4-sulfonatophenyl)porphyrin and their Zn complexes. For all these compounds, the following photodynamic therapy parameters were optimized: cell concentration, dye loading concentration, loading time and irradiation procedure. The non-toxic doses of porphyrins were different according to their structure: for 5,10,15,20-tetra(1-naphthyl)porphyrin compounds, the dose was of 10 μg.mL-1, and for 5,10,15,20-tetra(4-sulfonatophenyl)porphyrin compounds, the dose was 20 μg.mL-1. Cell functionality was assessed as membrane integrity, viability, and number of metabolically active cells. Photodynamic cell degradation kinetics showed that during irradiation tumor cells are actively destroyed, in contrast to unloaded cells. K562 cells loaded with the above-mentioned compounds and subjected to irradiation, displayed lower proliferative capacity compared to the control, for a period of 72 h after irradiation. The proliferative capacity of K562 cell line was more strongly inhibited by the 5,10,15,20-tetra(1-naphthyl)porphyrin family of compounds than by the 5,10,15,20-tetra(4-sulfonatophenyl)porphyrin family. The tested synthetic porphyrins showed effective antineoplastic activity against K562 leukemia cells in our in vitro photodynamic therapy experimental model.

Efficacy of Photodynamic Therapy on Inflammatory Signs and Two Selected Periodontopathogenic Species in a Beagle Dog Model

Current research aims to find alternatives to conventional methods for suppressing periodontopathogenic bacteria. Photodynamic therapy (PDT) could be a suitable treatment procedure of periodontal infections. In the present study, the PDT method was tested with two photosensitizers, chlorine e6 and BLC1010, in an experiment on beagle dogs. The animals were infected with Porphyromonas gingivalis (Pg) and Fusobacterium nucleatum (Fn) in all subgingival areas. After infection, we observed clinical signs of gingival inflammation, including an increase of redness and bleeding on probing. Microbiological monitoring before and after treatment was performed using polymerase chain reaction (PCR). PDT was conducted with a diode laser with a wavelength of 662 nm using a power of 0.5 W and the photosensitizers. The PDT procedure carried out with either of the photosensitizers caused a significant reduction in the clinical inflammation signs of redness and BOP, compared to the controls (laser only and no treatment). Furthermore, PDT with chlorine e6 caused a significant reduction in P. gingivalis-infected sites, whereas there was a lack in suppression after PDT with BLC1010. F. nucleatum could hardly be reduced with chlorine e6, and only to a certain extent with BLC 1010 and laser only. In the control groups, the Pg-infected test sites did not change. This study demonstrated that the photodynamic therapy using photosensitizer and a 662 nm laser light source is distinctly advantageous in reducing the periodontal signs of redness and bleeding on probing. The procedure also appears to significantly suppress P. gingivalis.

Metvix PDT (Photodynamic Therapy) Procedure Protocol

Australasian Journal of DermatologyVolume 46, Issue s3 p. S15-S15 Metvix PDT (Photodynamic Therapy) Procedure Protocol First published: 15 March 2005 https://doi.org/10.1111/j.1440-0960.2005.ajd_metvix_p1.pdf.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume46, Issues3February 2005Pages S15-S15 RelatedInformation

Light irradiation increases embryotoxicity of photodynamic therapy sensitizers (5-aminolevulinic acid and protoporphyrin IX) in chick embryos

Photodynamic therapy (PDT) of malignant processes is based on the ability of a photosensitizer to first, accumulate in malignant (immature) tissue and second, to be destroyed following light irradiation. Because of the similarity between malignant and embryonic immature tissues, we investigated the deleterious effect of the PDT procedure on day 4 chick embryos in ovo. We compared experimentally the photodynamic effect (light-toxic) and the side effect (dark-toxic) of the clinically attractive photosensitizers 5-aminolevulinic acid (ALA) and protoporphyrin IX (PP IX). The dark and light embryotoxicity (i.e. lethality plus teratogenicity) was determined after intra-amniotic injection of one of a range of dose of each compound. Under dark conditions, PP IX exhibited embryotoxicity at a dose of 10 μg/embryo; however ALA did not exhibit embryotoxicity even at the highest dose (300 μg/embryo). Light irradiation of embryos following injection induced strong embryotoxic effects of both substances even at dark-ineffective doses.

Light Sources and Delivery Devices for Photodynamic Therapy in the Gastrointestinal Tract

This article provides discussion on different light sources and light delivery devices used for photodynamic therapy of a variety of gastrointestinal malignancies. Different laser and nonlaser sources are discussed with emphasis on most commonly used clinical units. The discussion of light delivery devices is divided into several sections, each reviewing the evolution of fiberoptic delivery devices for different gastrointestinal malignancy. A discussion is provided on power meters and wavelength calibration devices used to assure proper light dosimetry. Finally, a short discussion is provided on a technique used to improve endoscopic monitoring of photodynamic therapy procedure during the treatment.

The treatment of malignant endobronchial obstruction with laser ablation

We compared a new endoscopic treatment for malignant endobronchial obstruction known as photodynamic therapy (PDT) with the more established therapy of neodymium: yttrium-aluminum garnet laser (Nd:YAG) therapy. A retrospective review was conducted of the medical records at our institution from 1988 to 1999 of patients treated for bronchial obstruction by thermal laser vaporization (Nd:YAG) or by PDT using the tunable dye laser in combination with a light-sensitive dye (PDT). The Nd:YAG procedure vaporized the obstructing neoplasm, whereas the PDT procedure photoablated the obstruction. Thirty-day mortality and morbidity rates were analyzed for both treatment groups using chi-square analysis. Of the 102 patients who were suitable for review, 83 received treatment with the Nd:YAG laser and 19 patients received treatment with PDT. Morbidity rates were comparable in both groups (22% for Nd:YAG vs 31% for PDT; P > .05). Equally common complications in both groups were respiratory failure and hypoxemia. Five Nd:YAG patients (6%) died within 30 days after treatment (3 of respiratory failure, 2 of massive hemoptysis), whereas 2 patients (10%) in the PDT group (1 of massive hemoptysis, 1 of acute myocardial infarction) died (P > . 05). PDT and Nd:YAG have similar mortality and morbidity rates. In our experience, PDT is a better choice for the treatment of malignant bronchial obstruction because it is technically easier, potentially safer, and does not require general anesthesia.

The treatment of malignant endobronchial obstruction with laser ablation

<h2>Abstract</h2> <b>Background:</b> We compared a new endoscopic treatment for malignant endobronchial obstruction known as photodynamic therapy (PDT) with the more established therapy of neodymium: yttrium-aluminum garnet laser (Nd:YAG) therapy. <b>Methods:</b> A retrospective review was conducted of the medical records at our institution from 1988 to 1999 of patients treated for bronchial obstruction by thermal laser vaporization (Nd:YAG) or by PDT using the tunable dye laser in combination with a light-sensitive dye (PDT). The Nd:YAG procedure vaporized the obstructing neoplasm, whereas the PDT procedure photoablated the obstruction. Thirty-day mortality and morbidity rates were analyzed for both treatment groups using chi-square analysis. <b>Results:</b> Of the 102 patients who were suitable for review, 83 received treatment with the Nd:YAG laser and 19 patients received treatment with PDT. Morbidity rates were comparable in both groups (22% for Nd:YAG vs 31% for PDT; <i>P</i> > .05). Equally common complications in both groups were respiratory failure and hypoxemia. Five Nd:YAG patients (6%) died within 30 days after treatment (3 of respiratory failure, 2 of massive hemoptysis), whereas 2 patients (10%) in the PDT group (1 of massive hemoptysis, 1 of acute myocardial infarction) died (<i>P</i> > .05). <b>Conclusions:</b> PDT and Nd:YAG have similar mortality and morbidity rates. In our experience, PDT is a better choice for the treatment of malignant bronchial obstruction because it is technically easier, potentially safer, and does not require general anesthesia. (Surgery 1999;126:730-5.)

NPe6と半導体レーザー併用PDTによるマウス接触性過敏症の抑制効果

The purpose of this study was to determine that photodynamic therapy (PDT) using mono-L-aspartyl chlorin e6 (NPe6) and a diode laser radiation can induce a state of systemic immunosuppression. The effect of treatment on immunological responses were evaluated by examining the capacity of transcutaneous PDT with NPe6 and light to inhibit hypersensitivity to trinitrochlorobenzene (TNCB) in Balb/c mice.The reduction in TNCB-induced ear swelling in PDT treated mice were compared to untreated mice. Pretreatment of mice with PDT resulted in 65% suppression of contact hypersensitivity to TNCB. Inhibition of the response could be produced even when sensitization with TNCB was attempted 2 weeks after PDT procedure. Prior sensitization or challenge with TNCB followed by PDT also decreased at 50% suppression of their response to TNCB. Thes decreased reactivity exhibited not only the induction but also the elicitation phase of the reaction. In adoptive transfer studies, it was shown that the immunosuppression was associated with the adherence to plastic dishes in spleen cells.

Temperature monitoring during photodynamic therapy of skin tumors with topical 5-aminolevulinic acid application.

Temperature monitoring during photodynamic therapy (PDT) with topical 5-aminolevulinic acid (ALA) cream application was performed on 22 patients with solar keratoses (SK) and basal cell carcinoma (BCC). The lesions were located on the forehead, nose, ear and cheek. Temperature measurements during photoirradiation, with a power density of 100 mW/cm2 from an incoherent light source (light delivery system for PDT), were carried out by noncontact (infrared thermal imaging radiometer) and contact (thermocouple) methods. Thermal imaging analysis revealed nonuniform temperature distribution in the irradiated areas. The temperature gradually increased from the peripheral to the central zone of the area. The results showed that photoirradiation induced heating of the skin tumors to 39.5-42.5 degrees C during the PDT procedure. The temperature of normal skin areas disposed symmetrically to the lesions on the contralateral side at the same conditions of irradiation (without prior ALA application) was about 42-43.5 degrees C. The surface temperature differences (delta T) between the normal and tumor tissues after 10 min of irradiation were 3.3 +/- 0.5 degrees C in the forehead areas, 2.5 +/- 0.4 degrees C in the nose areas and 0.8 +/- 0.3 degrees C in the ear areas.