• 대한소아치과학회지
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• 제47권2호
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• pp.120-127
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• 2020

이 연구의 목적은 치면착색제인 10 - 20 mM erythrosine을 광감각제로 사용한 광역동 치료의 항균 효과를 평가하는 것이다. Streptococcus mutans, Lactobacillus casei, Candida albicans를 포함하는 다종 우식원성 세균막을 hydroxyapatite disc에 형성하였다. 광감각제로 20 μM, 10 mM, 20 mM erythrosine을 3분간 적용 후 24초 동안 광조사를 시행하였다. 각 실험군의 Colony-forming unit (CFU)을 측정하고 세균막을 Confocal laser scanning microscopy (CLSM)을 이용하여 관찰하였다. 10 - 20 mM erythrosine을 광감각제로 사용한 광역동 치료 실험군에서 CFU의 현저한 감소가 관찰되었고, 그 결과는 CLSM 관찰에서도 확인되었다. 이번 연구를 통해 치과 임상에서 사용되는 치면착색제를 광감각제로 이용한 광역동 치료의 높은 항균효과를 확인할 수 있었다.

• 대한의생명과학회지
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• 제15권1호
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• pp.87-91
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• 2009

In photodynamic therapy (PDT), oxygen plays important role. Because of singlet oxygen which is produced by activated photosensitizer after laser irradiation of specific wavelength. The aim of this study is to find how oxygen concentration affects anticancer effect in PDT. Groups were divided into PDT with oxygen applied group and only PDT applied group. PDT with oxygen applied group supplied oxygen for 15 minute before laser irradiation. In vitro, CT-26 cell was incubated with various concentration of photofrin $(50.0{\sim}0.05{\mu}g/ml)$ and was irradiated with 632nm diode laser 6hr after application of photofrin. The cell viability of two groups was assessed by MTT assay. In vivo, CT-26 cell line was transplanted into the subcutaneous tissue of BALB/c mouse. The anticancer effect of two groups was measured by tumor volume change. In vitro study, the cell viability was significantly decreased at $1.56{\sim}3.13{\mu}g/ml$ in PDT with oxygen applied group. In vivo study, the PDT with oxygen applied group significantly higher reduction rate of tumor volume 7 days after PDT compared to PDT only group. The high oxygen concentration might enhance the anticancer effect of the photodynamic therapy.

• Journal of Photoscience
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• 제9권2호
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• pp.509-511
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• 2002

In this study, we investigated apoptotic cell death induced by photodynamic therapy using 5-aminolaevulinic acid (ALA-PDT) in human promyelocytic leukemia cells (HL-60). ALA-PDT induced apoptosis in HL-60 cells as confirmed by DNA agarose gel electrophoresis and nuclear staining with Hoechst 33342. The apoptotic cell death was inhibited by addition of broad-spectrum caspase inhibitor Z-Asp-CH$_2$-DCB, indicating that the apoptotic cell death was induced in a caspase-dependent manner. Actually, western blotting analysis revealed that caspase-3 was processed as early as 1.5 h after ALA-PDT. Cytoplasmic cytochrome c released from mitochondria was detected by western blotting. However, inhibitor of caspase-9, a cysteine protease located in the downstream of cytochrome c release, was not able to reduce the apoptotic cell death. Therefore, the mitochondrial apoptotic pathway was not involved in the ALA-PDT-induced apoptosis. On the other hand, it was found that ALA-PDT-induced apoptosis was clearly inhibited by pretreatment of caspase-8 inhibitor. These data suggest that caspase-8-mediated apoptotic pathway is important in ALA-PDT-induced cell death.

• 대한의생명과학회지
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• 제17권4호
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• pp.363-366
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• 2011

Eradication of $H.$ $pylori$, usually carried out by using antimicrobial agents, is essential for preventing gastric ulcers and cancers. The $H.$ $pylori$ isolates, however, have continuously grown antimicrobial resistance, which have caused difficulty in treating the bacteria and in turn, photodynamic therapy (PDT) has been found to be effective in inducing deaths of variety of bacteria. After PDT treatment, the number of colony forming units (CFU), the morphologic changes, and flow cytometry were observed. In the PDT group containing 100 and 200 ${\mu}g$/ml photogem, no live $H.$ $pylori$ was observed, while 10 and 50 ${\mu}g$/ml photogem were only partially effective. $H.$ $pylori$ of the PDT group also displayed distortion and shrinkage in morphology. This study demonstrated that photogem-mediated PDT effectively induces deaths of $H.$ $pylori$.

• 대한의생명과학회지
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• 제14권4호
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• pp.263-267
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• 2008

Photodynamic therapy (PDT) is a treatment utilizing the generation of singlet oxygen and other reactive oxygen species (ROS), which selectively accumulate in target cells. Peroxiredoxin (prx) plays an important role in eliminating peroxides generated during metabolism. Prx exert protective antioxidant role in cells though peroxidase activity. The aim of present work is to investigate the cytotoxicity of photofrin-mediated PDT in prx IV-transfectant AMC-HN3 cell lines. We confirmed that PDT has an effect on ROS generation in prx IV-induced cell lines. Treatment of PDT in prx IV-HN3 cell lines inhibits cytotoxic effects. Prx IV-induced HN3 cell lines resists in cell death during PDT. Also, prx IV-HN3 cell lines treated PDT inhibited ROS generation in contrast with vector control. We indicated that prx IV-induced AMC-HN3 cell lines have a function as inhibitors during PDT.

• 대한의용생체공학회:의공학회지
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• 제25권1호
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• pp.49-55
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• 2004

본 논문은 쥐의 악성종양에 대한 광역학적 치료효과를 조사한 연구이다. 실험방법으로서는 쥐를 대조군과 대상군의 두 그룹으로 나누어 HepG2 and Hela cell line을 주입하여 암조직을 배양하였다. 쥐의 악성종양에 포토포린을 30시간 전에 주입하고 630nm와 650nm의 레이저를 적용하였다. 광역학적 치료후에 쥐의 두 그룹에 대한 악성종양크기, 괴사율, 악성종양 성장률, 악성종양조직의 병리학적 변화를 분석하였다. 실험결과 조직에서 악성종야세포의 괴사를 보였으며, 광조사 시간과 광량에 따라 악성종양 크기가 줄어들고 악성종양의 괴사변화를 나타냈다. 그러나 630nm와 650nm의 파장차이에 대한 악성종양의 변화의 차이는 발견할 수 없었으며 다른 정상조직에서의 손상도 발견되지 않았다.

• Molecular & Cellular Toxicology
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• 제2권1호
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• pp.1-6
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• 2006

Photodynamic therapy (PDT), a newly established treatment for solid tumors, involves the systemic administration of a tumor localizing photosensitizer that is only activated when exposed to light of appropriate wavelength. Photoactivation of photosensitizer in the presence of oxygen results in the formation of highly cytotoxic molecular species, which precipitates necrosis. PDT has now become a promising means for the treatment of cancer due to its specificity, relatively minimal side effects, and inexpensive. However, the application of PDT has been restricted to the treatment of superficial lesions or the use of interstitial light delivery. A single photon generally activates the photochemical reaction in traditional PDT. However the use of multi photon excitation, where two or more photons simultaneously excite a photosensitizer, allows for the use of wavelengths twice as long. Such wavelengths exhibit better transmittance through tissue and thereby deeper penetration is achieved. This paper will review theoretical principles of multi photon excitation, challenges associated with multi photon PDT and update the current and future role of multi photon PDT in cancer.

• 대한방사성의약품학회지
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• 제9권1호
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• pp.35-41
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• 2023

Photodynamic therapy (PDT), in which a photosensitizer (PS), light, and molecular oxygen are essential components, is a non-invasive and highly effective cancer therapeutic method. However, PDT suffers from the penetration limit of light caused by attenuation and scattering of light through tissues constraining its use to skin and endoscopically accessible cancers. Cerenkov luminescence (CL) is defined as the light illuminated when charged particles move in a dielectric medium at a velocity greater than the phase velocity of light. It is known that medical radioisotopes in preclinical and clinical settings have enough energy to generate CL, and lately, CL has been exploited as an excitation source for PDT without external light illumination. This review introduces state of the art studies of radioisotope-based PDT for cancer, in which radioisotopes are utilized as a light source.

• 대한소아치과학회지
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• 제51권1호
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• pp.32-39
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• 2024

This study evaluated the additive impact of ethylenediamine tetraacetic acid (EDTA) on erythrosine-mediated photodynamic therapy (PDT) against Streptococcus mutans (S. mutans) biofilm by measuring colony-forming units and applying confocal laser scanning microscopy. Fifty-six bovine incisors, free from dental caries or structural defects, were utilized in this study. Dentin specimens were created by cutting with a low-speed diamond disk under a continuous flow of water, resulting in dimensions of 6.0 mm × 3.0 mm × 2.0 mm. The specimens were categorized into 4 groups: Control, EDTA, PDT, and EDTA + PDT. S. mutans ATCC 25175 was employed to establish biofilm on the dentin specimens. A 17% EDTA solution was applied for 1 min. For PDT, erythrosine served as the photosensitizer. Finally, a light-emitting diode source (385 - 515 nm) was employed in this study. The PDT group exhibited a significantly lower bacterial count than both the control and EDTA groups (p < 0.001). The EDTA + PDT group demonstrated a significantly reduced bacterial count compared to the other 3 groups (p < 0.001). This study demonstrated that EDTA enhances the antimicrobial efficacy of PDT on S. mutans biofilm. Even at a low concentration of photosensitizer, the combination of EDTA and PDT yields a significant antibacterial effect.

• 한국고분자학회지:고분자과학과기술
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• 제19권2호
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• pp.138-145
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• 2008