Mutsuhiko Murai

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.

MDM2 overexpression with alteration of the p53 protein and gene status in oral carcinogenesis.

In this study, to better understand the mechanism of oral squamous cell carcinoma (SCC) carcinogenesis, alterations of the p53 gene and overexpression of MDM2 and p53 were analyzed in 38 oral SCC samples. Twelve of the 38 specimens revealed mutant‐type p53. Moreover, coexpression of MDM2 and p53 was found most frequently in dysplastic lesions (P< 0.05). Expression of MDM2 and p53 was significantly increased in accordance with the histological progression of multistep carcinogenesis (P< 0.05). No significant correlation was found between the expression of MDM2 and the alteration of p53 protein or p53 gene status. MDM2 overexpression with mutant p53 was significantly associated with poorly differentiated SCCs (P< 0.05) and tumor stages III and IV of oral SCCs (P< 0.05). These results suggest that MDM2 overexpression is an early event in oral carcinogenesis through the functional inactivation of the wild‐type p53, and corresponding alterations of MDM2 and p53 contribute to the oral carcinogenesis. We propose that it would be clinically more instructive to evaluate MDM2 overexpression combined with p53 gene status, compared to the evaluation of either MDM2 or p53 alteration alone.

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.