カナマイシンによる聴力障害に関する臨床例と実験的検索

　I．緒言

　カナマイシン（以下KM）は1955年梅沢により長野県の土壤中より分離した放線菌の1新種Streptmyces Kanamyceticusの培養液中に産生された新抗生物質でありグラム陽性菌，陰性菌，更に抗酸性菌に対して強力な阻止作用を有する。

　又他の抗生物質に耐性を示した葡萄球菌，大腸菌，赤痢菌にも効力を示すと云われている。

Cases of hard of hearing caused by kana-mycin therapy are observed. In many cases kanamycin may be used without any hearing disturbances but, in some, if has been noted that a small amount of the drug had caused a high degree of deafness.

Comparing the effects of kanamycin that caused deafnees to that of streptomycin by using cat's cochlear microphonic response as indicator, it was found that the former was greater than the latter. Kanamycin pantote-nate was found to be less toxic than the str-aight kanamycin. The decomposition products of kanamycin, dioxystreptamin and kanoramin failed to produce any toxic effects on the ear.

Toxic effects on the vestibular labyrinth appear to be less with kanamycin that strep-tomycin but, by microscopic examination cellular changes were noted in the corti or-gan, cerebellar cortex and cell neucleus of the cells of the vestibule