Pregnant guinea pigs were treated with Kanamycin at three different stages of gestation (dating by method of post-partum ovulation). Twenty-nine newborn guinea pigs were tested electrophysiologically by recording the cochlear microphonic potential and the compound action potential from the round window in response to clicks and filtered clicks at 8,000 Hz. Six of the test animals showed the same electrophysiological changes as those found in adult mammals after Kanamycin intoxication. The results suggest a relationship between the ototoxicity of Kanamycin and the onset of auditory function. Cochlear potential and compound action potential were mostly affected when intoxication was performed during the last 15 days of gestation. This study confirms the results previously published by Uziel 1979.

Action Potentials↗

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Results of an ultrastructural study comparing stria vascularis with organ of Corti in guinea pigs treated with kanamycin.

Ultrastructural study of ototoxicity is well documented with two points of interest: organ of Corti for aminoglycosides and stria vascularis for loop diuretics. As a previous study suggested initial lesions of stria vascularis, an attempt of comparison and of chronological study was made between the organ of Corti and stria vascularis lesions by kanamycin intoxication. The method was devised by J. M. ARAN, with electrophysiological control. We failed to find in the stria vascularis a radial or longitudinal pattern of lesions. We could not discern a chronological injury between the organ of Corti and stria vascularis because both were damaged even in the less deafened animals. Nevertheless, two facts were clarified: hair cell lesions are lysosomial as for the kidney lesions, while stria vascularis lesions are mitochondrial, melanine granulations play a part in drug metabolism (increased number, secretory aspect) and deserve further study.

Animals↗

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Melanine value in the stria vascularis of pigmented guinea-pigs treated by kanamycin.

In a previous report, kanamycin (400 mg/kg/d) seemed to increase the number of melanine granulations in intermediate cells of the stria vascularis, especially in the second and third turns. To precise these data, melanine was studied in those turns by ultrastructural morphometry in a control group with 12 animals. We observed a large intra-individual and inter-individual variation before intoxication. Thus, the meaning of melanine modifications by kanamycin must be carefully evaluated.

Animals↗

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[Surgical treatment of traumatic facial paralysis].

Facial paralysis caused by cranial traumatism often needs surgical treatment / 28 operations were carried out on a group of 47 paralysed patients. Direct lesion of the facial nerve was in fact common / 10 compressions or contusions, 4 sections. Associated kophosis was frequent (15 cases). Conductive deafness was not uncommon (11 cases). Transverse fractures (5 cases) and complicated fractures (4 cases), true to their reputation for seriousness, all needed surgery and span the four nerve sections observed. Surgery is often delayed due to extensive cranio-cerebral lesions requiring prolonged neuro-surgical nursing care / 16 patients were operated on between the 4th and 8th weeks, 9 patients after the 8th week. The operation was usually carried out through the mastoid. Posteiror lympanotomy enabled the bend and the second portion to be reached and later enabled the ossicular chain to be reconstructed. In two cases involving kophosis, the three portions of the nerve were tackled through the labyrinth. The choice depends on the audiometric, radiological and operative findings. Surgical indications depend on clinical, elecromyographic, audiometric and radiological results. A check was carried out by means of muscular tests in 23 out of 28 cases: --20 decompressions / 15 recuperations of more than 50 p. 100 of which 7 were above 75 p. 100; --3 grafts or sutures / 3 recuperations of 30 p. 100.

Adolescent↗

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