. . "IntroductionIt is known that damage or deficit of skin and mucosa, such as injury, wound, morsus, scald, burn, congelation, radiation injury, ultraviolet irradiation, electric injury, traumatic injury, skin ulcer, bedsore, and bullous skin diseases, causes degenerative exfoliation, necrosis, apoptosis, or apoptosis-like cell death of skin tissue-composing cells or mucosal tissue-composing cells." . .