インドシアニングリーンの血漿消失率測定にっき, モンテカルロ法と光子拡散理論による近似解法を用いて評価した. 消失率の評価は光学的に均一に混濁な組織モデルに対して実施した. シミュレーション結果により, 本モデルに対しては, 拡散近似による方法がモンテカルロ法より安定であった. 拡散近似により求めた混濁組織モデルでの血漿消失率は, 混濁度を考慮しない場合に比して低い値を示した. 本結果は, よく臨床結果を反映していると考えられた.

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マウスのSMT-F乳癌を用いてPDTの基礎的な研究を行った. Photofrin II(DHE, 5mg/kg)とアルゴンダイレーザー(630nm)によるPDTを行いpower densityと energy density の条件によるが, 腫瘍に深さ5mmから10mmの壊死を起こすことが判明した. これをもとに, 1996年2月73歳の女性で以前に各種の治療(1988年に根治的乳房切断術施行)を受けた局所再発乳癌の患者にPDTを応用した. PDTは, DHEを2mg/kg静注し, 48時閤後にエキシマダイレーザー(630nm)を8mJ/pulse, 40Hz, 134J/cm2の条件で照射した. レーザーの照射外にPDT施行3ヵ月半後に新しく腫瘍結節を認めた. しかし, 患者が1997年10月に乳癌で死亡するまで1年10ヶ月の間PDTで治療したところには腫瘍の再増殖は認めなかった. 再発乳癌の患者に PDT を用いる場合, いくつかの問題点が挙げられた. 1) レーザーの照射条件が確立していないこと, 2) 体表の腫瘍の正確な厚さ診断ができないこと, 3) 表在腫瘍のPDTに保険の適応がないこと, 4) Photofrin-PDT には光制限が長期間必要であること, そして 5) 臨床においてPDT効果を早期に評価できるよい手法がないことである.

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A photodynamic therapy (PDT)-resistant variant of the P388 murine leukemia cell line was isolated by repeated PDT with mono-L-aspartyl chlorin e6 (NPe 6) in vitro to the 0.1% survival level, followed by twelve regrowth cycles. The resistant variant was 1.38-fold more resistant to PDT with NPe 6 (10-15 μg/ml). However, more than 20 μg/ml, there was no difference between cells. The PDT-12 cells had less uptake of NPe 6 after 2h incubation than P388. We examined cross-resistance to adriamycin and the partitioning behavior determinant of the aqueous biphasic system. There was no difference in cytotoxicity and the uptake of adriamycin (ADM) between parental and PDT-12 cells. Partitioning behavior of parental cells and PDT-12 cells was compared. The latter has an inherently higher degree of membrane hydrophobicity. NPe 6 is comparatively hydrophilic, but the P388/ADR cells had reduced accumulation of the drug by extrusion by P-glycoprotein rather than membrane hydrophobicity. Furthermore, NPe 6-PDT cytotoxicity depended on accumulation into cells. Therefore, the PDT-12 cells acquired a hydrophobic membrane by repeating NPe 6-PDT twelve times. The PDT-12 cells were not cross-resistant to adriamycin. NPe 6 penetration into PDT-12cells was prevented by membrane hydrophobicity.

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レーザー光の医学・医療応用では, レーザー光を自在に操るために, そのレーザー光伝送路である光ファイバー技術はなくてはならないものである. では, 光ファイバーとはどんなもので, どのようにして, 光 (レーザー光) を閉じこめて伝送することができるのか? 本講座では, この質問に対して, 予備知識のない方々にも理解して頂けるように, できるだけ数式を少なくして, 写真とイラストで平易に解説する.

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Optical coherence tomography (OCT) is a new technology for performing high resolution cross sectional imaging. OCT is analogous to ultrasound imaging, except that it uses light instead of sound. OCT can provide cross sectional images of tissue structure on the micron scale in situ and in real time. Using OCT in combination with catheters and endoscopes enables high resolution intraluminal imaging of organs. OCT functions as a type of optical biopsy and is a powerful imaging technology for medical diagnostics because unlike conventional histopathology which requires removal of a tissue specimen and processing for microscopic examination, OCT can provide images of tissue in situ and in real time. OCT can be used where standard excisional biopsy is hazardous or impossible, to reduce sampling errors associated with excisional biopsy, and to guide interventional procedures. In this paper, we review OCT technology and describe its potential medical applications.

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Objective: To introduce an office or bedside method of evaluating both the motor and sensory components of swallowing called Flexible Endoscopic Evaluation of Swallowing with Sensory Testing (FEESST). FEESST combines the established endoscopic evaluation of swallowing with a technique that determines laryngopharyngeal sensory discrimination thresholds by endoscopically delivering air pulse stimuli to the mucosa innervated by the superior laryngeal nerve.
Methods: Endoscopic assessment of laryngopharyngeal sensory capacity followed by endoscopic visualization of deglutition was prospectively performed 148 times on 133 patients with dysphagia over an 8 month period. The patients had a variety of underlying diagnoses, with stroke and chronic neurological disease predominating (n=94). Subsequent to sensory testing, a complete dysphagia evaluation was conducted. Various food and liquid consistencies were dyed green and attention was paid to their management throughout the pharyngeal stage of swallowing. Evidence of latent swallow initiation, pharyngeal pooling and/or residue, laryngeal penetration, laryngeal aspiration and / or reflux was noted. Recommendations for therapeutic intervention were based upon information obtained during the FEESST and involved dietary and behavioral modifications, prevention of oral alimentation and/or referral to other related specialists.
Results: All patients successfully completed the examination. In 111 of the evaluations (75%), severe (>6.0mm Hg air pulse pressure) unilateral or bilateral LP sensory deficits were found. With puree consistencies, 47% of evaluations with severe deficits compared to 11% of evaluations with either normal sensitivity or moderate (4.0-6.0mm Hg air pulse pressure) sensory deficits displayed aspiration (p<.001, chi-squared test). With puree consistencies, 69% of evaluations with severe deficits compared to 24% with normal or moderate deficits displayed laryngeal penetration (p<.001, chi-squared test).
Conclusion: FEESST allows the clinician to obtain a comprehensive sensorimotor assessment of swallowing that is performed as the initial swallowing evaluation for the patient with dysphagia.

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