• Journal of the korean academy of Pediatric Dentistry
• /
• v.49 no.2
• /
• pp.149-157
• /
• 2022

The aim of this study was to evaluate the effects of erythrosine-mediated photodynamic therapy (PDT) on Streptococcus mutans biofilm recovery by counting its colony-forming units (CFUs) and via confocal laser scanning microscopy analysis at different time points following PDT. In PDT, photosensitizer was an erythrosine. S. mutans ATCC25175 biofilms were irradiated using an LED curing light. Chlorhexidine (CHX) was used as positive control. After each antimicrobial treatment, samples were cultured to allow biofilm recovery. Viability was measured by calculating the CFU counts after treatment and after every 3 hours for up to 24 hours. Immediately after treatment, the PDT and CHX groups showed equally significant decreases in S. mutans CFU counts compared to the negative control. After 12 hours of reculture, the PDT group showed no significant difference in the decrease in CFU count compared to the negative control, whereas the CHX group showed significantly lower CFU counts throughout the 24-hour period. Erythrosine-mediated PDT can effectively inhibit S. mutans biofilm formation. However, biofilm recovery occurred earlier in the CHX group after PDT. This study provides insights into the clinical effectiveness of PDT in preventing dental caries.

• Proceedings of the KIEE Conference
• /
• 2005.05a
• /
• pp.36-38
• /
• 2005

Photodynamic diagnosis is a modern method for the fluorescence imaging of cancer. 5-ALA induced protoporphyrin IX fluorescence benefits the tumour selective accumulation of protoporphyrin ; therefore, tumours can be differentiated from healthy tissue. This paper develops Photodynamic diagnosis (PDD) system about ALA that apply tissue absorption coefficient. About other photosensitizer, application capacitate. In this paper, we will expect effective result by working PDD with PDT (photodynamic therapy) system that is a therapy device of cancer.

• Journal of the Korean Applied Science and Technology
• /
• v.28 no.1
• /
• pp.102-108
• /
• 2011

The study of wave propagation and scattering in biological media has become increasingly important in recent years. The propagation of light within tissues is an important problem that confronts the dosimetry of therapeutic laser delivery and the development of diagnostic spectroscopy. In the clinical application of photodynamic therapy(PDT) and in photobiology, the photon deposition within a tissue determines the spatial distribution of photochemical reactions. Scattered light is measured as a function of the distance (r) between the axis of the incident beam and the detection spot. Consequently, knowledge of the photosensitizer(Chlorophyll-a) function that characterizes a phantom is measured. To obtain the results of scattering coefficients(${\mu}s$) of a turbid material from diffusion described by experimental approach. It was measured the energy fluency of photon radiation at the position of penetration depth. From fluorescence experimental method obtained the analytical expression for the scattered light as the values of $(I/I_o)_{wavelength}$ vs the distance between the center of the incident beam and optical fiber in terms of the condition of "in situ spectroscopy(optically thick)" and real time by fluorometric measurements. The result was compromised with transport of intensities though a random distribution of scatters.

• Journal of the Korean Applied Science and Technology
• /
• v.22 no.2
• /
• pp.182-190
• /
• 2005

The propagation of light radiation within tissues is an important problem that confronts the dosimetry of therapeutic laser delivery and the development of diagnostic spectroscopy. In the clinical application of photodynamic therapy(PDT) and in photobiology, the photon deposition within a tissue determines the spatial distribution of photochemical reactions. Scattered light is measured as a function of the distance (r) between the axis of the incident beam and the detection spot. Consequently, knowledge of the photosensitizer(Chlorophyll-a) function that characterizes a phantom is important. To obtain the results of scattering coefficients(${\mu}s$) of a turbid material from diffusion described by experimental approach. It was measured the energy fluency of photon radiation at the position of penetration depth. From fluorescence experimental method obtained the analytical expression for the scattered light as the values of $(I\;/I_o)_{wavelength}$ vs the distance between the center of the incident beam and optical fiber in terms of the condition of "in situ spectroscopy(optically thick)" and real time by fluorometric measurements.

• Biomedical Science Letters
• /
• v.17 no.1
• /
• pp.79-84
• /
• 2011

Photodynamic therapy consists of a photosensitizer, suitable light source and oxygen. The excitation of the photosensitizer at a cancer mass results in oxidation which would ultimately reduce the mass via apoptosis. Millimeter wave (MMW) therapy has also been known to be effective on cancer cell mass reduction, human cell regeneration and immunity enhancement among the Russian clinicians and scientists. In the present study, the two modalities were combined to achieve synergistic effects while reducing the administration dosage of the photosensitizer, photogem, thus minimizing the side effects. The CT-26 adenocarcinoma cell mass was implanted on mice and the tumors were exposed to a simple MMW irradiation or a combined treatment of MMW and PDT. The treatments continued for 4 weeks and the size of the tumor was measured continuously. The significant therapeutic result of MMW was not found during 4 weeks, preferably more cancer recurrence possibility after MMW irradiation was observed. The results of this study suggest that the combination of MMW irradiation and photodynamic treatment should not be recommended. The result of the MMW treatment alone, however, displayed suppressive effect on cancer cell proliferation for both in vitro and in vivo. The results of the present study suggest that the millimeter wave therapy deserves a further study.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.5
• /
• pp.3351-3355
• /
• 2013

Photodynamic therapy (PDT) is a promising cancer treatment modality that uses dye-sensitized photooxidation of biologic matter in target tissue. This study explored effects of the photosensitizer BCPD-17 during PDT for osteosarcoma. LM-8 osteosarcoma cells were treated with BCPD-17 and cell viability after laser irradiation was assessed in vitro with the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. The effects of BCPD-17 during PDT recurrence were then examined on tumor-bearing mice in vivo. BCPD-17 had dosedependent cytotoxic effects on LM-8 osteosarcoma cells after laser irradiation which also had energy-dependent effects on the cells. The rate of local recurrence was reduced when marginal resection of mice tumors was followed by BCPD-17-mediated PDT. Our results indicated BCPD-17-mediated PDT in combination with marginal resection of tumors is a potentially new effective treatment for osteosarcoma.

• Journal of Veterinary Clinics
• /
• v.37 no.1
• /
• pp.1-8
• /
• 2020

Canine otitis externa is a common disorder in small animal practice with prevalence up to 20%. In a large percentage of cases, canine otitis externa is a chronic and recurrent disease also associated with drug-resistant bacteria that is difficult to treat with traditional antibiotics. Photodynamic therapy (PDT) is a new strategy to exterminate pathogenic microorganisms such as bacteria and fungi. The purpose of this study was to investigate the effectiveness of photodynamic therapy against canine otitis externa using three photosensitizer (PS); 5-Aminolevulinic acid (5-ALA) and Methyl aminolevulinic acid (MAL) with semiconductor laser diode (SLD, 635nm of wave length), Chlorophyll-lipoid complex (CLC) with light-emitting diode (LED, 660nm of wave length). After PDT, dogs showed improved Otitis Index Score (OTIS) in swelling, exudate, odor, and pain. A result of the cytology test revealed decrease of bacteria and malassezia count in the oil immersion field and colony forming units count. PDT was effective as a bacteriocide of methicillin-resistant Staphylococcus pseudintermedius (MRSP) and a fungicide of Malassezia pachydermatis. MAL and 5-ALA were more effective PS against canine otitis externa than CLC. These results suggest that PDT is a new strategy to exterminate pathogenic microorganisms such as bacteria and fungi. PDT can be considered as a new therapeutic approach for canine recurrent otitis externa and a countermeasure to drug resistance that is a disadvantage of traditional antibiotic and antifungal therapy.

• Tuberculosis and Respiratory Diseases
• /
• v.71 no.4
• /
• pp.266-270
• /
• 2011

Background: Photodynamic therapy (PDT) is effective in managing small superficial early lung cancer patients who were deemed nonsurgical candidates. However, we do not have any previous report on the usefulness of PDT in early lung cancer in South Korea. Thus we report here our experience of PDT in early lung cancer patients. Methods: 10 patients who underwent PDT for managing early lung cancer between June 2006 and July 2010 were analyzed. PDT was carried out 48 hours after photosensitizer injection. Re-bronchoscopy was carried out 48 hours after PDT in order to remove a necrotic tissue from the PDT site. For evaluation of PDT response, bronchoscopy and chest computed tomography (CT) were performed after 3 months. Results: The median age of patients was 69 (49~77) and all patients were male. The smoking history of patients was 48 (20~75) pack-year and the median follow up of patients was 25 (11~52) months. Complete remission was observed in 10 patients and the recurrence of lung cancer was observed in 3 patients. Out of 10 patients, 3 patients died (one case of lung cancer progression and two cases of pneumonia). Conclusion: The PDT is a safe and effective treatment in early lung cancer patients who are not suitable for surgical resection. The PDT in clinical practice is an attractive option in the treatment of early lung cancer.

• Progress in Medical Physics
• /
• v.16 no.2
• /
• pp.104-109
• /
• 2005

Photodynamic therapy (PDT) is one of the expectable current cure operation methods. Tumor tissue is treated by abundant oxygen in a body and generated singlet or free radical from exterior laser diode and photosensitizer. Current problem of PDT is the low penetration power of the light beam in a deep seated large tumor and solid tumor thus results in low treatment outcome. In the study, we tried to develop interstitial photodynamics therapy treatment to solve this problem. As the accurate determination of light dosimetry in biological tissue is one of the most important factors affecting the effectiveness of PDT, parameters used in this study are the optical property of biological tissue. Since biological tissues have large scattering coefficient to visible light the penetration depth of a biological tissue in visible light region is only $15\~20$ mm. We showed that it is possible to measure fluence rate and penetration depth within the biological tissues by Monte Carlo simulation very well. Based on the MC simulation study, the effectiveness of interstitial photodynamic therapy on tumor control in solid tumor was proved through in vivo animal experiment.

• Biomaterials Research
• /
• v.22 no.4
• /
• pp.303-310
• /
• 2018

Background: Photodynamic therapy (PDT) is photo-treatment of malignant or benign diseases using photosensitizing agents, light, and oxygen which generates cytotoxic reactive oxygens and induces tumour regressions. Several photodynamic treatments have been extensively studied and the photosensitizers (PS) are key to their biological efficacy, while laser and oxygen allow to appropriate and flexible delivery for treatment of diseases. Introduction: In presence of oxygen and the specific light triggering, PS is activated from its ground state into an excited singlet state, generates reactive oxygen species (ROS) and induces apoptosis of cancer tissues. Those PS can be divided by its specific efficiency of ROS generation, absorption wavelength and chemical structure. Main body: Up to dates, several PS were approved for clinical applications or under clinical trials. $Photofrin^{(R)}$ is the first clinically approved photosensitizer for the treatment of cancer. The second generation of PS, Porfimer sodium ($Photofrin^{(R)}$), Temoporfin ($Foscan^{(R)}$), Motexafin lutetium, Palladium bacteriopheophorbide, $Purlytin^{(R)}$, Verteporfin ($Visudyne{(R)}$), Talaporfin ($Laserphyrin^{(R)}$) are clinically approved or under-clinical trials. Now, third generation of PS, which can dramatically improve cancer-targeting efficiency by chemical modification, nano-delivery system or antibody conjugation, are extensively studied for clinical development. Conclusion: Here, we discuss up-to-date information on FDA-approved photodynamic agents, the clinical benefits of these agents. However, PDT is still dearth for the treatment of diseases in specifically deep tissue cancer. Next generation PS will be addressed in the future for PDT. We also provide clinical unmet need for the design of new photosensitizers.