제목 [12/01] [colloquium] Treatment of gastrointestinal infectious diseases by phototherapy
작성자 물리학과홈피 등록일 2015-11-27 오후 1:41:34 조회수 213
추천 0 비추천 0
날 짜 : 2015년 12월 1일 화요일
시 간 : PM 4:30
장 소 : R404
연 사 : 채현석 교수님 (가톨릭의대)
제목:  Treatment of gastrointestinal infectious diseases by phototherapy

Photodynamic therapy (PDT) is a method using photosensitizer (PS) and light sources of specific wavelength to treat malignant tumors or localized infectious diseases. Reactive oxygen species (ROS) generated by the photodynamic reaction induce damage to multiple cellular structures including the cell membrane, cell wall and nucleic acid, which leads to bactericidal and anti-cancer effects. The Gram-negative Helicobacter pylori (H. pylori) chronically infects the human gastric mucosa resulting in gastritis, peptic ulcer, and gastric cancer. Until now, its treatment is based on antibiotic therapy in spite of gradual increase of resistance. So, PDT might be another method to treat H. pylori because it has only one repairing gene (uvrA) about phototoxicity-induced DNA damage. With treatment of 0.02mg/ml methylene blue and white light of endoscopy, bacteria decreased approximately a hundredfold. Its effect increased proportionally to the PS concentration and duration of irradiation. Clostridium difficile (C. difficile) causes a severe colitis with high recurrence and mortality. Treatment of C. difficile infection is also based on antibiotics in spite of the increase of resistance. There has been no investigation about PDT against C. difficile. For the first time, in vitro PDT was performed with UVA, tetracycline (TC) as a photosensitizer (PS) and chitosan (booster agent). At 1 mg/mL of TC, chitosan treatment combined with PDT, increased the bactericidal effect by >10,000-fold of the effect of PDT alone.  

Conclusion: PDT against pathologic GI infection with antibiotic resistance, might be an useful, effective and alternative method with development of medical device to deliver PS and oxygen to targeting site. 

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