アミノ配糖体系抗生物質のモルモット聴覚器におよぼす影響
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概要
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Study was carried out on the ototoxic effects of some aminoglycoside antibiotics, such as Vistamycin (VSM), Kanamycin (KM), and Gentamycin (GM), on experimental animals including adult, single nephrectomized, and newborn guinea pigs. A comparison of the ototoxic effects of each antibiotic was made by performing Preyer's pinna reflex test after consecutive intramuscular injections of these antibiotics, using an audiometer with the frequency range of 8000 to 10000 Hz and histopathological examination. The results are as follows:<BR>A) Adult guinea pig<BR>All guinea pigs receiving 400 mg/kg of VSM for 35 days showed the normal threshold of pinna reflex, and there was no histopathological change in their ears. All guinea pigs receiving 400 mg/kg of KM for 35 days caused complete disappearance of pinna reflex, and the loss of outer hair cells in Corti's organ was found throughout their entire turns. In guinea pigs receiving 80 mg/kg of GM for 35 days, one of them was normal in threshold but the rest caused disappearance of pinna reflex. According to the histopathological examination, one animal was in normal state but the rest caused complete loss in the outer hair cells turning over twice until the latter half.<BR>B) Single nephrectomized guinea pig<BR>By giving the same dosage as described above, guinea pigs showed the normal states not only in the reflex test but also in the histopathological examination of their inner ears. Animals receiving 400 mg/kg of KM for 35 days caused disappearance of inner reflex. According to the histopathological examination, outer hair cells in Corti's organ were deficient throughout their entire turns. Animals receiving 80 mg/kg of GM for 35 days caused complete disappearance of pinna reflex, but five of them were a partial or complete loss of outer hair cells throughout their entire turns.<BR>C) Newborn guinea pig<BR>Newborn guinea pigs, whose mothers were under administration of 400 mg/kg of VSM, showed a slight increase in threshold of pinna reflex, but there was no change in their microscopic examination. In newborn guinea pigs, whose mothers were under administration of 200 mg/kg of KM, most of them led to an increase in threshold of the reflex test but a few were normal. By the histopathological examination, the loss of marginal cells in the stria vascularis was observed in all animals, a few of which showed the loss of outer hair cells within the limits of the basal end turning over once. Two mothers died during this experi-ment but three delivered nine newborn animals. Six newborn animals led to an increase in threshold of the reflex test but the rest was normal. The loss of marginal cells in the stria vascularis was observed in all newborn animals, in some of which the loss of outer hair cells was localized in the basal end turning over once.
- 昭和大学・昭和医学会の論文