Ichiro Yamada

Analysis of photosensitivity in Japanese cancer-bearing patients receiving photodynamic therapy with porfimer sodium (PhotofrinTM)

A major disadvantage of a new cancer treatment, porfimer sodium (PhotofrinTM)‐mediated photodynamic therapy (PF‐PDT), is photosensitivity for several weeks after cessation of the treatment. To characterize persistent sensitivity to visible light following PF‐PDT, phototestings were performed in 59 Japanese cancer‐bearing patients with a slide projector lamp 3 weeks or more after the treatment. The duration of photosensitivity was analyzed in relation to the patients’ sex, skin phototype (SPT), site of tumor and liver function. There was no correlation of the photosensitivity persistency with the site of cancers and the function of liver. However, female subjects needed significantly longer recovery periods than male subjects from potential photosensitivity after PF‐PDT. Patients with SPT2 were significantly more sensitive than patients with SPT3 and 4. These results suggest that the prolonged photosensitivity occurs after PF‐PDT especially in female patients and in cases with a lighter SPT. Such patients should be carefully followed up for post‐PDT photosensitivity.

5-Aminolaevulinic acid-mediated photodynamic therapy in multidrug resistant leukemia cells.

To verify if photodynamic therapy (PDT) could overcome multidrug resistance (MDR) when it it applied to eradicate minimal residual disease in patients with leukemia, we investigated the fluorescence kinetics of 5-aminolaevulinic acid (ALA)-induced protoporphyrin IX (PpIX) and the effect of subsequent photodynamic therapy on MDR leukemia cells, which express P-glycoprotein (P-gp), as well as on their parent cells. Evaluation of PpIX accumulation by flow cytometry showed that PpIX accumulated at higher levels in mdr-1 gene-transduced MDR cells (NB4/MDR) and at lower levels in doxorubicin-induced MDR cells (NOMO-1/ADR) than in their parent cells. A P-gp inhibitor could not increase PpIX accumulation. Measurement of extracellular PpIX concentration by fluorescence spectrometry showed that P-gp did not mediate the fluorescence kinetics of ALA-induced PpIX production. Assessment of ferrochelatase activity using high-performance liquid chromatography indicated that PpIX accumulation in drug-induced MDR cells was probably regulated by this enzyme. Assessment of phototoxicity of PDT using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that PDT was effective in NB4, NB4/MDR, NOMO-1 and NOMO-1/ADR cells, which accumulated high levels of PpIX, but not effective in K562 and K562/ADR cell lines, which accumulated relatively low levels of PpIX. These findings demonstrate that P-gp does not mediate the ALA-fluorescence kinetics, and multidrug resistant leukemia cells do not have cross-resistance to ALA-PDT.

Interstitial photodynamic therapy with rotating and reciprocating optical fibers

Photodynamic therapy (PDT) is an effective treatment modality that allows selective destruction of malignant tumor cells. However, because of the difficulty in exposing deeper areas of tumors, the modality has strictly limited indications. In this study, the authors introduce a new method for delivering laser light to a three‐dimensional, wide area with the purpose of improving the therapeutic value of PDT.

Tissue distribution of a new photosensitizer ATX-S10Na(II) and effect of a diode laser (670 nm) in photodynamic therapy

The aims of the present study were to analyse the quantitative tissue distribution of ATX-S10Na(II) and to investigate the maximal effect of a diode laser and the irradiation conditions required to obtain this effect in photodynamic therapy (PDT) with ATX-S10Na(II). Spectrofluorometry was used to obtain quantitative tissue distribution of ATX-S10Na(II) in Colon 26 carcinoma-bearing mice as a function of time following administration. Next, transplanted tumours of mice with or without ATX-S10Na(II) were treated with the diode laser under conditions in which power density and irradiation time were varied. Tumour tissue concentrations of ATX-S10Na(II) were higher than in all tissues at all intervals following administration. The uptake of ATX-S10Na(II) by most tissues was rapid, with maximal concentrations occurring 1 h after i.v. injection, and ATX-S10Na(II) was almost excreted within 24 h after administration. The maximal depth of necrosis induced by PDT in the treated tumour was 7.9 mm under conditions in which power density was 160 mW/cm2 and total dose was above 100 J/cm2. PDT with ATX-S10Na(II) and the diode laser is useful for the treatment of superficial cancers.

Photodynamic therapy with intradermal administration of 5-aminolevulinic acid for port-wine stains.

Objective: To investigate whether intradermal administration of 5-aminolevulinic acid (5-ALA) could achieve a sufficient amount of protoporphyrin IX (PpIX) to induce photochemical reaction in chicken comb, the animal model of port wine stains (PWSs). Methods: PpIX accumulation after 5-ALA administration through intradermal or intravenous injection was monitored for 24 hours. Localization of PpIX was observed under a confocal microscope. The comb was exposed to red light after intradermal 5-ALA injection, and the subsequent changes were observed grossly and microscopically. Results: In the comb, PpIX accumulation achieved the peak level at 5 and 4 hours after intravenous or intradermal injection of 5-ALA, respectively, and was almost completely eliminated within 24 hours. A similar amount of PpIX was observed in both groups. While in the body skin, a lower level of PpIX was observed after intradermal injection. A confocal microscope showed that PpIX distributed evenly in comb dermis without significant difference between the two groups. The vascular structure in comb was disrupted after laser irradiation based on intradermal administration of 5-ALA. Conclusions: Intradermal injection of 5-ALA is a safer administration route that could achieve the equivalent of PpIX accumulation and destroy vasculature after PDT. It might be applicable to the clinical treatment of PWSs.

Autofluorescence Diagnosis for Oral Squamous Cell Carcinoma

We made spectral analysis in patients with oral SCC using a UVexcited autofluorescence photographic apparatus and found that there were a bimodal peak at 630 and 680nm at the excitation wavelength of 410nm we found a clear difference from the autofluorescence of the oral cavity of normal human subjects and oral benign diseases. We considered that fluorescence diagnosis of oral SCC would be possible by means of this method. (平 成10年12月3日 受 理,Received December 3rd 1998) 40 日 レ医 誌(JJSしSM)第20巻 第1号(1999)

The development of lesion imaging fluorescence diagnostic apparatus

We have developed the fluorescence diagnostic apparatus of oral lesion. In this study, we analyzed autofluorescence of SCC and leukoplakia. Both cases of SCC and leuk oplakia, we found two fluorescence peaks. In case of SCC, a major peak was at 628 nm and a smaller peak was at 668 nm. As regard to intensity, the maximal intensity of SCC was 18 times stronger than that of normal oral mucosa. In case of leukoplakia, a major peak was at 658 nm and smaller peak was at 627 nm. The maximal intensity of leukoplakia was five times stronger than that of normal oral mucosa. The results suggested that the autofluorescence diagnosis of oral lesion would be possible by new fluorescence diagnostic apparatus.

The short-term Biolgical Effects of KrF

The purpose of this study was to investigate the short-term biological effects of Excimer Laser. The surface of the skin in the rat was irradiated with KrF Excimer Laser at wave length of 248nm for 30 seconds at pulse repetition rate of 10Hz and pulse width of 15nsec.Energy density was 3.1mJ/cm2, 47.6mJ/cm2, 160.0mJ/cm2, 576.9mJ/cm2 or 1714.2mJ/cm2.The irradiated skin tissue was removed of various times between 1 hour and seven days after rradiation and with H-E stain for pathological examination. Necrosis was observed in epidermis irradiated at 47.6mJ/cm2 and in dermis irradiated at 576.9mJ/cm2, and defect of the muscular tunic was observed in tissue irradiated at 1714. 2mJ/cm2. These results indicate that depth of skin defect is related to energy density and that necrosis occurs at energy density ranging from 3.1mJ/cm2 to 47.6mJ/cm2. Satisfactory wound was observed after irradiation at each energy density.

[Clinical cytogenetic studies in patients with cleft lip and/or cleft palate. 1. G-banding technique].

Judging from the studies on twins with cleft lip and/or palate, it seems to be a fact that the disease is hereditary. According to previous studies, they reported that patients with cleft lip and/or palate showed almost the same pattern of inheritance as the multifactorial inheritance. However, as shown in the report (Tanaka et al., 1973) in which it assumed that it was the multifactorial inheritance, with regard to the morbidity rate there is a great difference between the observed value and the expected value. This does not always satisfy the assumption of multifactorial inheritance. We considered this point and tried the chromosome analysis using the G-band technique on three groups of cleft lip, cleft palate, and cleft lip and palate on included twelve subjects (two males and two females in each group) . That is, in this study approximately 550 bands were analyzed in detail and the results that they had no chromosome aberration were obtained. We think that the results do not mean that patients with clefts have no chromosome aberration, the problem being the chromosome banding technique we used. In order to investigate this point, we will make a study using the high-resolution banding technique to in the families which have sibs with cleft lip and/or palate and cases of twins with clefts.