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The influence of different fixation methods and of various primary fixatives on the ultrastructural preservation of guinea pig cochlear tissues was investigated. No differences in fixation quality were observed between cochleas fixed by intravascular perfusion and cochleas fixed by intralabyrinthine perfusion. Tri-aldehyde primary fixation resulted, in contrast to other formulae investigated, in an excellent, uniform preservation of all cochlear tissues without obvious fixation artefacts. The influence of OSO4/K4Ru(CN)6- and OSO4/K4Fe(CN)6 postfixation was also tested. Cochlear tissues postfixed with OSO4/K4Ru(CN)6 or OSO4/K4Fe(CN)6 exhibited more cellular detail (e.g., membrane- and glycogen contrast) as compared to tissues postfixed with OSO4 alone. Tri-aldehyde primary fixation followed by OSO4/K4Ru(CN)6- or OSO4/K4Fe(CN)6 postfixation therefore is recommended as a multipurpose procedure for optimal preservation of labyrinthine tissues.

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The early identification of hearing impairment allows for an intervention still in the "critical" and ideal period of hearing and language stimulation. Pediatric ototoxicity is a very controversial topic. There have been variable percentages of ototoxicity cases in children with different aminoglycosides antibiotics. The main pediatric groups whom receive aminoglycosides are newborns with severe infections on the neonatal ICU. Aim: to check the functional aspect of the cochlear external hair cells and treatment regimens used to treat infections during the neonatal period. Study design: Experimental. Materials and Methods: we studied 26 albino guinea pigs, through distortion product otoacoustic emissions, before and after the use of gentamicin. Results: in all the assessments, the external hair cells functional status, studied by means of the distortion product otoacoustic emissions, proved preserved. Conclusion: In the present study, we did not notice changes in outer hair cell function in the albino guinea pigs treated with gentamicin in the doses of 4 mg/Kg/ day and 2.5 mg/Kg/day every 12 hours for 10 and 14 days.

The clinical, audiovestibular and histopathological findings in a patient who suffered from a long-standing gentamicin-induced deafness are reported. In both temporal bones, the organ of Corti was completely absent, with only a few nerve fibres remaining in the apical part of the cochlea. Regenerative ingrowth of nerve fibers into the area of the degenerative organ of Corti was present apically in both ears. The stria vascularis exhibited considerable degeneration in all turns and loss of microvasculature was found in the basilar membrane. The spiral ganglion cells, the cochlear nerve and the central auditory pathways and nuclei appeared to be unaffected.