The repair process of neomycin induced cochlear damage in the postnatal developing rat was investigated in the present study. The results showed that electron dense atypical cells with a cluster of microvilli on their apical surface, resembling early stage of embryonic hair cell, were observed in the former hair cell region. The striking finding was that microglia-like cells appeared and replaced OHCs in the injured auditory sensory epithelium. Using Brdu immunohistry, cell prolifera-tion was found in the area of inner and outer spiral sulcus but not in the hair cells and supporting cells. It is proposed that microglia-like cells play a role in eliminating waste products from the organ of Corti and may participate in direct structural repair. NeuroReport 11: 1389-1393

The apoplosls occurring in the postnatal developing spiral ganglion cells (SGCs) and Ihe concomitant change in Bax-prolein immunmeuctlvity were investigated in rats at postnatal days (P) I, 3, 5, 7, l0 and 14, and also in adull rats In P5 and P7 rals, some neurons showed structural features of poptosis, includlng cell shrinkage, condensed chromatin around the margin of the nucleus and phagocytosis of apoptotic bodies by satellite coils. The percentage of Bax-protein- positive neurons ill the spiral ganglion was significantly higher in PI, P3, PS, lind P7 rat5 compared with adult rats Our resulls conflm the oecurrace of neuronad cell apoptosis in the splmal ganglion at the end of the first ostllatal week, and demonstrate the trallsJent chalge in Bax-plotein immunorcactlvity prior Io neuronal cell apoplosJs Thus, we speculate that the Iransient change in Bax protein could be involved in neuronal cell apoptosis of the postnatal developing SGCs of rats.

To investigate regeneration of the distal facial nerve following nerve grafting within the tympanic segment with geniculate ganglion preservation of dissection.

Fr the efficacy and saftey of the surgical manipulation in stapedotomy for otosclerosis, the author did such surgery using CO2 lair in 44 cases. postperative follow up (3-12 months) reveals that hearing mean gain is 31+75:8.2 dB and air-bone conduction gap is within 11, 25:6.6 dB. There is no significant change at 4000 Hz. The advantages of CO2 laser tenlque are summarized as follows: convenience for cutting posterior crus, less lime eonuming for penetration on thick footpkate or removal of occlusive slerotic plaque within the oval window niche, avoidance of footptate flatlng with slight fixation of fooplate, and rapid coagulation of residual stzpedia artery as well as no instrumental difficulties at some narrow spaces. Our results state that CO2 lair creates essntial improvement in the development of the stapedotomy in otosclerosis.

Objective To investigate into the option to surgical procedures in different stages of Meniere's disease. Methods One hundred and nineteen cases (119 ears) of Meniere's disease operated on were reevaluated with the National Criteria (Chenese ENT Association, 1996). Forty-eight cases in second state underwent endolymphatic sac shunt (ESS); 32 cases in third stage underwent Scarpa gangliectomy (SGN) and 12 in the same stage Ess; 16 in fourth stage vestibulocchlear neurectomy (VCN) and others ESS (7 cases) and SGN (4 cases). Results (1) ESS successfully relieved vertigo in 79.2 per cent of the paticnts in second stage , and their hearing tended to stabilize (35.4%); (2) SGN was successful in controlling the vertigo of those patients in third stage who might retain. some usable hearing; (3) paticnts underwent VCN in stage 4 expericnced a rapid elimination of tinnitus. Conclusions The postoperative results were highly de-pendent on careful staging and selection of the surgical method.

Twenty-one cats have been subjected to stredch injunics to extratemporal nerve segment. Histologically the stretch injury of the facial nerve induced a retrograde spread of degeneration reaching its meatal scgmcnt. The centripetal degeneration is most likely due to the direct elongation of the nerve fibcrs within the intact intratemporal cpincurium. The massive fibrosis occumingin the extratemporal as well as in the mastoid segment followin stretching . impairs regencration inducing a longer delay and a reduction in the number of axons reaching the peniphery. The obtaincd results indicate that resection of the mastoid segment hould be considered when a grafing procedure has to be performed in human following stretch injury to the facial nerve in the parotid region.