Nakagawa Kouichi, Minakawa Satoko, Sawamura Daisuke
Division of Regional Innovation, Graduate School of Health Sciences, Hirosaki University.
Department of Dermatology, Graduate School of Medicine, Hirosaki University.
Anal Sci. 2018;34(7):837-840. doi: 10.2116/analsci.18P055.
We investigated melanin radicals in paraffin-embedded malignant melanoma (MM) using a surface-type dielectric resonator for X-band electron paramagnetic resonance (EPR) and analyzed the radical species. The surface-type resonator's performance was examined using 5 - 10 μL of 0.1 mM 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) aqueous solution in a 1.0-mm (i.d.) glass capillary as well as 1,1-diphenyl-2-picrylhydrazyl (DPPH) powder. The surface-type detection has approximately two times poorer S/N ratio than commercial insertion-type detection. A sample of the paraffin-embedded MM specimen was used for the radical detection. We obtained an EPR spectrum of melanin radicals in the paraffin-embedded melanoma sample (size ∼3 × 4 × 3 mm). A single line (∼0.64 mT peak-to-peak line-width) with a small shoulder was observed and was identified as a pheomelanin-related radical. The pheomelanin radical can be directly related to the MM. Thus, the present results were a good indication for noninvasive measurement, as well as for detailed analyses of melanin radicals in human MM.
我们使用用于X波段电子顺磁共振（EPR）的表面型介质谐振器研究了石蜡包埋恶性黑色素瘤（MM）中的黑色素自由基，并分析了自由基种类。使用1.0毫米（内径）玻璃毛细管中5 - 10微升0.1毫摩尔/升的4-羟基-2,2,6,6-四甲基哌啶-1-氧基（TEMPOL）水溶液以及1,1-二苯基-2-苦基肼（DPPH）粉末来检测表面型谐振器的性能。表面型检测的信噪比大约比商用插入型检测低两倍。石蜡包埋的MM标本样本用于自由基检测。我们获得了石蜡包埋黑色素瘤样本（尺寸约为3×4×3毫米）中黑色素自由基的EPR谱。观察到一条带有小肩峰的单线（峰-峰线宽约为0.64毫特斯拉），并将其鉴定为与褐黑素相关的自由基。褐黑素自由基可能与MM直接相关。因此，本研究结果对于非侵入性测量以及对人类MM中黑色素自由基的详细分析是一个很好的指示。
