We studied the distribution and the photocytotoxicity of photosensitizers in the cultured tumor cells. A cultured Colon 26 cell line derived from BALB/c was used. The hydrophilic photosensitizers, ATX-S10Na (II), PAD-S31 and the amphipathic photosensitizer, Photofrin^® were used. The cellular localization and the cell-damage mechanisms of the photosensitizers were analyzed under a video-microscope.
The localization of ATX-S10Na (II) and PAD-S31 was mainly in lysosomes of the cultured cells, that was relocalized in the cytoplasm within a second of illumination. The localization of Photofrin^® was in the cytoplasm of the cultured cells. The cells containing each photosensitizer were swollen and shrunken and died by exposure of the light.

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It is known that low power laser irradiation causes many biological effects including improvement of topical blood perfusion. For chemotherapies of malignant diseases, if a low power laser irradiation is able to increase a blood flow within a tumor, it may lead to better concentration of chemotherapeutic agents in objective sites, enhancing antitumor effect. We have conducted a clinical examination to confirm this phenomenon for the lung cancer patients using He-Ne laser as a light source. Nineteen patients who had inoperable lung cancer evaluable bronchofiberscopically were offered this therapeutic modality. Histologically, they consisted of 5 lesions of adenocarcinoma, 2 lesions of small cell carcinoma, 11 lesions of squamous cell carcinoma and 2 of other histologic types. Undertopical anesthesia, He-Ne laser (MERA COLD LASER Senkou Ika, Tokyo, Japan, WL; 632.8nm, 8.5mW) was irradiated to the whole visible site of the tumor using quartz fiber through the channel of a fiberoptic bronchoscope. Fluence of irradiations were 6J/cm2 Simultaneously, conventional chemotherapeutic agent was administered intravenously. To evaluate the therapeutic effect, bronchofiberscopy was performed 1, 2, 5, 7 and 10 days after therapy and assessed cytologically or histologically. Complete remission (CR) was obtained in 3 cases. Partial remission and no changes were found in 8 cases for eac h. Response time of CR cases was within 5 days. Basic study also must be necessary to elucidate the biological or cytological mechanisms.

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Immortalized cloned human chondrocytes isolated from normal (Ch-4, 8, N) and osteoarthritis specimen (Ch-8-OA) were established by introducing of recombinant SV40-adenovirus vector containing SV40 early gene. These cells were exhibited continuous proliferative capacity in monolayer culture and showed chondrocytic characteristics in that they were positive for alkaline phosphatase and collagen type II. When cells were treated with IL-1α, the growth of these cells were inhibited. The growth of Ch-8-OA was significantly inhibited by treatment with TNFα Introduction of TGFβ into the culture stimulated the growth of all four cloned chondrocytes, though GM-CSF only stimulated the growth of Ch-8-OA. Enhanced ⁴⁵Ca accumulation into the chondrocytes was observed by treatment with TGFβ and GM-CSF. Interestingly, AlGaInP diode laser irradiation stimulated the growth of all four cloned chondrocytes and enhanced ⁴⁵Ca accumulation was also observed. The fact that AlGaInP diode laser irradiation stimulated the growth of both chondrocytes originated from normal and osteoarthritis specimen as well as TGFβ treatment, may provede a basis for the clinical use of laser irradiation in osteoarthritis patients.

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It is important to detect the near infrared emission of 1.27 IA in wavelength from the singlet oxygen, ¹O₂, to investigate and understand the mechanism of PDT. We detected this emission by means of a photon-counting system comprised with a high sensitive photomultiplier tube. For the efficient detection by this system, delayed detection time of 5μs from the onset of the laser irradiation and detection time duration of 5μs were necessary for the aqueous solution of photosensitizer PHE, and 8μs and 50μs were necessary for HeLa-tumor bearing mice injected with PHE (25mg/kg). The life time of the ¹O₂, was 5.3μs for the aqueous solution of PHE and 114μs for the HeLa-tumor bearing mice injected with PHE.

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