Photodynamic therapy (PDT) is a light based therapy used to ablate tumors. As practiced in oncology a photosensitizing agent is applied and then activated by a specific wavelength and energy of light. This light energy in the presence of oxygen will lead to the creation of the photodynamic reaction which is cyto and vasculo toxic. This paper will review the mechanisms of action of PDT and how they may be manipulated to improve clinical outcome in cancer patients.
Humans ; Light ; Oxygen ; Photochemotherapy ; Photosensitizing Agents ; Triazenes

Authors studied how Claude Bernard, the first founder of experimental medicine, contributed significantly to establishment of modernism and influenced European modern culture. Authors first studied his views on modernity, comparing with Descartes and Magendie, and on the similarity between "Experimental medicine" and the European literature in the 19th century. Bernard was not exclusively against vitalism, but the dogmatic misuse of vitalism. His objective thinking could be a useful model for the authors, who considered science to be an origin of modernity in literature of naturalism. Especially, Emile Zola was strongly influenced by Bernard's "An introduction to the study of Experimental medicine" and published "Experimental novel," a manifesto of naturalism. Although Bernard's experimental methodology and determinism deeply influenced modern European culture, the relationship between his Experimental medicine and modernism have not been fully investigated yet. His experimental medicine also needs to be discussed from the ecological viewpoints. His anthropo-centrism was unique since he emphasized any human theory could not surpass the principle of nature. Conventional anthropo-centrism claims that human beings are superior enough to own and govern the nature. And Bernard's the necessary determinism contains the ecological principle that all life forms and inanimate objects are organically related and intertwined to each other, irrespectively of their usefulness for the human beings. Although there were some ethical debates related to his medical experiments on living bodies of animal, his strict principle to perform experiments only after animal or human body died was worth considering as an effort to sustain ecological viewpoints. He was also unique in terms of being realistic and candid about his situation which was limited by the 19th century's scientific and medical development. In conclusion, the significance of convergence of literature and medical science in Experimental medicine and the importance of Bernard's ecological viewpoints, need to be further studied in the field of medical history.
Animals ; Ecology ; Human Body ; Humans ; Photosensitizing Agents ; Silanes ; Thinking ; Vitalism

Photodynamic action, due to the rather limited lifetime (1 μs) and effective reactive distance of singlet oxygen (< 10 nm), could subcellular-specifically regulate different cellular functions. Photodynamic action could activate permanently cholecystokinin (CCK) 1 receptors, and sensitize or desensitize other G protein-coupled receptors. The emergence in recent years of genetically- encoded protein photosensitisers has enabled more precisely-targeted photodynamic modulation of subcellular organelles and functional proteins. Protein photosensitisers (such as KillerRed, miniSOG or SOPP) expressed on the plasma membrane, mitochondria, lysosomes or endoplasmic reticulum can modulate photodynamically subcellular functions and fine-tune protein activity by targeted photooxidation. With the newly emerged active illumination technique, simultaneous photodynamic action localized at multiple sites is now possible, and the contribution of subcellular regions to the whole cell or individual cells to a cell cluster could be quantitated. Photodynamic action with protein photosensitiser will be a powerful tool for nano-manipulation in cell physiology research.
Endoplasmic Reticulum ; Light ; Mitochondria ; Photosensitizing Agents ; Receptors, Cholecystokinin

Photodynamic therapy (PDT), because of its good targeting, minimal invasion, and safety, is becoming a very active area in cancer prevention and treatment, in which the photosensitizers have proved to be the core element for PDT. We developed a new HPLC method for analyzing porphyrin photosensitizers using Shiseido Capcell PAK C18 (150 mm x 4.6 mm, 5 µm) as the column at 30 °C, methanol-1% aqueous solution of acetic acid as the mobile phase in a flow rate of 1.0 mL · min(-1) in a gradient elution mode, and the detection wavelength at 380 nm. This method, showing good specificity, precision, accuracy and robusty via methodology validations, can be applied to the purity test and assay of porphyrin photosensitizers, and has played a key guide role in the R&D of the new porphyrin photosensitizer--sinoporphyrin sodium.
Chromatography, High Pressure Liquid ; Photochemotherapy ; Photosensitizing Agents ; chemistry ; Porphyrins ; chemistry

Despite its more than 100-year history in experimental and clinical use, photodynamic therapy (PDT) is only starting to be appreciated for its full potential. PDT combines a photosensitizer and light in the presence of oxygen to treat cancer and other disorders. This paper reviews the molecular mechanism of PDT at the cellular level as well as in therapeutic settings in vivo. The availability of multiple photosensitizers with different structures and functional properties makes PDT an extremely versatile and, conversely, a challenging approach to cancer therapy. The advancing understanding of molecular pathways helps to design improved regimens. As most cancers are being treated with combined therapies, PDT is being integrated into rationally designed regimens that exploit molecular responses to PDT for improved efficacy.
Humans ; Neoplasms ; drug therapy ; Photochemotherapy ; Photosensitizing Agents ; therapeutic use

To investigate the effect of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) on () biofilm. biofilms were constructed on a cell slide and treated with ALA-PDT.According to different light doses,the biofilms were divided into six groups:ALA-PDT group [ALA-PDT1 (50 J/cm),ALA-PDT2 group (100 J/cm),ALA-PDT3 group (200 J/cm)],ALA-only group (ALA group),light-only group (LED),and a negative control group (ALA-PDT-group).The biofilm structure and the ratio of the dead bacteria/live bacteria were observed using a laser confocal microscope (CLSM).Biofilm viability was measured using the XTT assay. CLSM showed that the biofilm structures of ALA group and LED group were not significantly different from that of ALA-PDT-group,whereas the biofilm structure was more seriously damaged in ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group than in the ALA-PDT-group.The ratios of the dead/live bacteria in ALA-PDT-group,ALA group,LED group,ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group were 0.350±0.033, 0.305±0.046, 0.330±0.032, 1.525±0.439, 2.293±0.148 and 3.092±0.189,respectively.ALA group(=0.003, =1.000)and LED group(=-0.025, =1.000)did not significantly differ from the ALA-PDT-group.However,the ratio of dead/live bacteria in ALA-PDT-group was significantly lower than those in ALA-PDT1 group (=-0.162, <0.001),ALA-PDT2 group (=-0.254, <0.001),and ALA-PDT3 group (=-0.352, <0.001).The values of the XTT assay were were 0.462±0.028,0.465±0.044,0.437±0.047,0.301±0.040,0.207±0.001,and 0.110±0.007,respectively,in ALA-PDT-group,ALA group,LED group,ALA-PDT1 group,ALA-PDT2 group,and ALA-PDT3 group.Although the values of XTT assay in ALA(=-0.044, =1.000)and LED groups (=-0.020, =1.000)did not significantly differ from that in ALA-PDT-group,it was significantly higher in ALA-PDT-group than in ALA-PDT1 group (=1.175, <0.001),ALA-PDT2 group (=1.942, <0.001),and ALA-PDT3 group (=-0.352, =2.742, <0.001). ALA-PDT has an inhibitory effect on biofilm.ALA-PDT destroys biofilm structure and inhibits biofilm viability.
Aminolevulinic Acid ; Biofilms ; Photochemotherapy ; Photosensitizing Agents ; Propionibacterium acnes

BACKGROUND: Recently, narrow-band UVB phototherapy is introduced for vitiligo treatment. It is easier to be applicable because of no need for topical and/or systemic photosensitizers, and comparably or more effective than PUVA without systemic side effects. Moreover, it is more safely applicable to children and pregnant women. However, to date, there is not so large series of clinical reports about its use in vitiligo treatment as to evaluate therapeutic effects. OBJECTIVE: This study was to evaluate the effects of narrow-band UVB phototherapy for vitiligo in various aspects of clinical parameters. METHODS: Treatment of patients in this study with narrow-band UVB was started between November 2001 and November 2002. Narrow-band UVB phototherapy was given as monotherapy once or twice a week. The starting dose was 280-300mJ/cm2, with dose increments at each subsequent treatment. RESULTS: 78 patients were able to be evaluated in this study. Their ages ranged from 3 to 67 years (mean, 33.7 years). 69 patients had Fitzpatrick skin type IV, 5 had skin type III and 4 had skin type V. 36 of the 78 patients (46.2%) achieved more than 75% repigmentation (grade 4). The better repigmentation grade, the shorter vitiligo duration (p=0.0464). Compared with other sites, lesions on the hands and feet showed poorer improvement(grade 1: 10/13 and 4/4 respectively, p= 0.0015). Adverse effects were limited and transient. CONCLUSION: Narrow-band UVB therapy is an effective and safe therapy for vitiligo. Long-term adverse and therapeutic effects compared to other treatment modalities remain to be determined.
Child ; Female ; Foot ; Hand ; Humans ; Photosensitizing Agents ; Phototherapy* ; Pregnant Women ; Skin ; Vitiligo*

It is believed that the photopatch test is a valuable screening procedure for the determination of responsible antigenic substances in photoallergic contact dermatitis. But the technigues used for this procedure are cumbersome and require expensive equipment. In the present study, we adapted an easy and inexpensive photopatch test met- hod to our need. We report the results of this test method which was performed. in 21 patients with photodermatitis and 9 patients with polymorphic light eruption. 1. The UVB sensitivity determined by minimal erytherna dose (mean+-standard deviation) was I1618mW sec/cm in photodermatitis group, 108+ROmW sec/cm in polymorphic light eruption group and 126-+32mW-sec/cm in control group. But there was no significant difference among them (p>0. 05). 2. The reaction to UVA were negative in all groups. R. The photopatch test using IO potential photosensitizers revealed 12 positive responses in 9 patients; including 7 patients in photodermatitis group and 2 patients in polymorphic light eruption group. And the number of positive photopatch responses obtaied with each photosensitizer in RO patients with photodermatoses was 5 in chlorhexidine, 2 in paraaminobenzoic acid, musk ambrette and bithionol and 1 in chlorpromazine, respectively.
Bithionol ; Chlorhexidine ; Chlorpromazine ; Dermatitis, Photoallergic ; Humans ; Mass Screening ; Photosensitivity Disorders ; Photosensitizing Agents

Clinical photodynamic therapy was introduced in the 1970s and has been shown to be an effective treatment modality in a variety of fields in oncology. Photodynamic therapy (PDT) is a local therapy such as radiation and surgery, which involves the photosensitization of neoplastic cells and tissues with porphyrins or related structures that catalyze, upon irradiation by laser, formation of reactive oxygen species. A photosensitizing agent is administered to the patient and after a period of 24-72 h when the concentration of the photosensitizer is maximized in tumor tissue compared with normal tissue, and then the neoplastic mass is exposed to the laser light, which initiates the necrotic process. Despite the ability of PDT to destroy the tumor selectively, it has not been applied widely due to the lack of understanding of its therapeutic mechanism and clinical experiences as well as some limitations of currently available photosensitizers. Nowadays, the number of scientific articles on PDT, regarding clinical applications as well as basic science, made its application increasing. In one of the most suitable indications, lung cancer, PDT is a minimally invasive therapeutic option for the treatment of early cancer in airway and palliation for the endobronchial obstruction from central lung cancer. In esophageal cancer, PDT can also be applied to treat in early stage without muscle invasion or remnant cancer after endoscopic mucosal resection. Besides, PDT can be applied as a part of combined modality such as a neoadjuvant or adjuvant PDT. With the advances of new sensitizers and energy delivery system, clinical application of PDT will expand in near future. This review article will focus on the basic mechanism and the clinical investigations of PDT for the clinicians.
Esophageal Neoplasms ; Humans ; Lung Neoplasms ; Photochemotherapy* ; Photosensitivity Disorders ; Photosensitizing Agents ; Porphyrins ; Reactive Oxygen Species

This paper reviews the use of photodynamic therapy (PDT) in patients with Barrett's esophagus and esophageal carcinoma. We describe the history of PDT, mechanics, photosensitizers for PDT in patients with esophageal disease. Finally, we discuss its utility and limitations in this setting.
Aminolevulinic Acid ; Barrett Esophagus ; Dihematoporphyrin Ether ; Esophageal Diseases ; Esophageal Neoplasms ; Humans ; Mechanics ; Photochemotherapy ; Photosensitizing Agents ; Triazenes