The electric discharge experiment, known as the Miller-Urey experiment, is one of the experiments to understand the origin of life on Earth. The experiment involved simulating the Earth’s early atmosphere by introducing methane(CH4), ammonia(NH3), and nitrogen(N2) gases, and applying energy through electric discharge. Resulting solution was found to contain amino acids such as glycine(C2H5NO2), alanine( C3H7NO2), histidine(C6H9N3O2), proline(C5H9NO2), and valine(C5H11NO2). These amino acids were compared with the results of the recent experiment (Parker et al. 2014). Interestingly, the electric discharge produced C2 swan band and CN emission and it was newly found in gas phase. These two emission bands are commonly observed in comets.

A 72 years old male complained of gingival ulceration and whitish discoloration on the marginal and attached gingival epithelium of left mandibular premolar and molar area, where a porcelain-fused metal (PFM) crown and an ill-fitting gold crown were applied for 10 years, respectively. Recently he had a cancer phobia due to this whitish lesion unhealed even after intensive anti-inflammatory and antibiotic treatment. In the pathological examination the epithelium was hyperkeratotic and acanthomatous with severe inflammatory reaction, and subsequently its basement membrane was distorted and the intercellular spaces between keratinocytes were widened. Particularly, the nuclei of keratinocytes were elongated in the same direction towards the electric current between the dissimilar metallic crowns of PFM gold. In the immunohistochemistry KL1, β-catenin, and S-100 were strongly positive in the epithelium, but consistently weak for TNFα, HSP-70, and β-defensin-1, -2, -3. On the other hand, PCNA, p53, E-cadherin, and pAKT were rarely positive for the epithelium. Interestingly, the hyperkeratinized and inflamed epithelium was strongly positive for a calcium binding protein (S-100), while it showed almost reduced expression of protective molecules (HSP-70, β-defensin-1, -2, -3, and pAKT). Therefore, it was presumed that this localized lichenoid gingivitis was caused by the galvanic current phenomenon with lower cellular and immunological responses contrary to the ordinary oral lichen planus and leukoplakia