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It is known that aminoglycoside antibiotics can damage the vestibular and auditory sensory epithelia, and the loop diuretics can enhance the ototoxic effect of aminoglycosides. Previous studies on the synergistic effect of these two types of drugs have used mice, guinea pigs and cats, but not rats. The aim of this study was to determine this synergistic effects in rat cochleae. Rats received intravenous injections of different doses of furosemide and/or intramuscular injections of kanamycin sulfate. Auditory brainstem response (ABR), scanning electron microscopy (SEM) and immunocytochemistry were used to determine the effects of drug administration. In the group receiving combined administration of furosemide and kanamycin, the ABR threshold showed significant elevation 3 days after drug administration, greater than single drug administration. The hair cells showed various degrees of injury from the apical turn to the basal turn of the cochlea and from the outer hair cells to the inner hair cells. Neuron fibers of the hair cells showed significant loss 7 days after the drug administration, but the number of spiral ganglia did not decrease and supporting cells showed no signs of injury. Our study suggest that combined administration of furosemide and kanamycin has an synergistic ototoxic effect, and can result in hair cell loss and hearing loss in rats.

Objectives To establish a method for high yield mesenchymal stem cells collection, as well as a culture method for identifying mesenchymal stem cells from the swine adipose-derived mesenchymal stem cell (ADMSC). Methods Swine ADMSCs were isolated from fat tissue with collagenase, followed by induction of differentiation to osteogenic, adipogenic and chondrogrnic cells. The survival curve of the ADMSC at the 37°C and 38°C were measured using WST-1Cell Proliferation Assay Reagent. Result ADMSCs isolated with collagenase from swine neck fat tissue generated a stable uniform appearance after the second generation. The passage period was five days. ADMSC could differentiate into osteogenic, adipogenic or chondrogrnic cells under different culture conditions. The highest growth rate was achieved at 38°C in this study. Conclusion Swine ADMSCs have the potential to differentiate into osteogenic, adipogenic or chondrogrnic cells, and they may be appropriate for transplantation for both research and clinical purpose.

Objective To investigate the suitability of miniature pigs as an animal model for otological research. Methods Microdissection of the temporal bone was performed on 10 miniature pigs and recorded on photographs. Results The morphology and measurement of the external, middle and inner ear and the lateral recess of the miniature pigs were obtained by microdissection. Conclusion Compared to traditional animal models, the miniature pig may be a better model for biomedical research because of its many similarities in physiological functions with humans. Similarities of the temporal bone structures, including the external, middle and inner ear and the lateral recess, between the miniature pig and human make the animal a potentially useful model for otological research.

Objective To report use of the Vibrant Soundbridge (VSB) in patients with congenital deformation of the middle and outer ears and investigate its utility in this patient population. Method Four patients with congenital deformation of middle and outer ears underwent VSB implantation. All were male (aged 3-18 years, average 13.5 years) and operated on the left side. Malformation was bilateral in 3 patients and unilateral in 1 patient. Surgical techniques were modified to accommodate each patient's unique conditions and needs. The implant site was approached via the facial recess in 3 patients and through a retro-facial nerve route in 1 patient. The VSB implant was connected to either the stapes (2 cases) or the round window (2 cases). Pure tone and speech audiometry results and daily communication capabilities before and after VSB activation were compared. Results The operations were successful in all patients, with no complications. The patient communication level improved significantly after VSB activation. Average air conduction pure tone threshold or conditioned reflex audiometry threshold improved by 35 dB in the 0.25-4 kHz range, from 69 dB HL before VSB activation to 34 dB HL after. The sentence recognition rate in quiet at 65 dB SPL went up to 86% from 0% without VSB for patients with bilateral deformation and remained at 100% for the patient with unilateral deformity. However, for the latter patient, the rate improved to 20% from 0% without VSB in noise (-8 dB SNR). Conclusion VSB is an excellent solution for improving hearing in patients with congenital deformation of middle and outer ears. Operation can be completed and good results can be achieved even in patients with unique conditions and needs.

Objective To report experiences with use of otoendoscopy in cerebellopontine angle (CPA) surgeries. Methods Twenty five cases of CPA surgeries performed between November 2002 and December 2008 in which microscope enabled otoendoscopy was used were reviewed.The 25 cases included 19 cases of acoustic neuroma, 3 cases of CPA facial nerve tumors, 1 case of trigeminal neurinoma, a case of glossopharyngeal neuralgia and 1 case of hemifacial spasm. Endoscopy was used in all cases together with monitoring of brainstem auditory responses and facial electromyography. Postoperative hearing and facial nerve function were evaluated and compared to pre-operative levels. Results Endoscopy provided improved visualization of local anatomy, revealed hidden lesions and reduced unnecessary anatomical distortions. Total resection was achieved in 18 of the 19 acoustic neuroma cases, Facial nerve anatomical integrity was preserved in all 19 cases. One week postoperative House-Brackmann grading was I in 3 cases, II in 10 cases and III in 6 cases. Facial nerve function continued to improve in some cases at 3 months. Total tumor resection was achieved in all 3 patients with facial neurinoma. The facial nerve was sacrificed in 2 of the 3 cases with primary faciohypoglossal nerve anastomosis. Facial nerve function was Grade II and Grade III one year after surgery, respectively. In the case with anatomically preserved facial nerve, postoperative facial nerve function was initially Grade III and improved to II at 3 months. The tumor was completely resected in the trigeminal neurinoma patient with a Grade III postoperative facial nerve function which improved Grade II three months later. Seventeen of the 19 patients with acoustic neuroma retained hearing postoperatively, of these 12 maintained preoperative levels of hearing. Preoperative hearing capacity was preserved in 2 of the 3 patients with facial nerve tumors, but lost in patients with other tumor types. Glossopharyngeal neurotomy (n=1) and microvascular decompression (n=1) resulted in satisfactory symptom relief and no recurrence at 5- and 3-year follow up, respectively Conclusions Otoendos aope-aided technique greatly helps surgical management of CPA and internal auditory canal lesions and other disorders. This minimally invasive technique overcomes many shortcomings inherent to the traditional retrosigmoid approach.

ObjectiveTo report tympanoplasty cases completed with Sheehy Partial Ossicular Replacement Prostheses (PORP).MethodsSeventy eight(83 ears) of 89 cases who received Sheehy PORP for ossicular chain reconstructionwere reviewed. These cases were followed for more than 6 months(mean: 21.3 months). The pre- and post-operative average air conduction thresholds and Air-Bone Gap(ABG) at 0.5, 1 and 2kHz were compared.ResultsAll 83 ears showed uneventful healing at 1 month postoperatively. PORPs in 2 ears without cartilage reinforcement were found dislocated at 3 months. Preoperative hearing thresholds were from 35.75 to 68.5 dB HL (mean: 59.13 ± 15.23 dB HL). Postoperative mean hearing threshold improved to 32.23± 13.21 dB HL (P

Objective To report the authors’ experiences in hearing preservation during acoustic neuroma (AN) resection procedures. Methods Two cases of AN removal via retrosigmoid approach were reviewed. Hearing preservation was attempted in the aid of endoscopic technique along with continuous monitoring of the compound action potential (CAP) and auditory brainstem response(ABR) during the surgery. Results The tumor in Case 1 was 1.5 cm in diameter. The average pure-tone hearing threshold was 30 dB HL and ABR was normal. Waves I, III and V of ABR were present following tumor removal. At 7th month follow-up, audiometric thresholds and ABR inter-peak intervals had recovered to pre-operative levels, with normal facial nerve function. The patient in Case 2 had bilateral AN. The tumors measured 4.0 cm(left) and 5.0 cm (right) on MRI scans. The AN on the right side was removed first, followed by removal of the left AN four months later. Intraoperative CAP monitoring was employed during removal of the left AN. While efforts to preserve the cochlear nerve were not successful, CAPs were still present after tumor removal. Conclusions Intraoperatively recorded CAPs are not reliable in predicting postoperative hearing outcomes. In contrast, ABRs are an indicator of function of the peripheral auditory pathway. Presence of waves I, III and V following tumor removal may represent preservation of useful hearing.

Objectives To study clinical, imaging features and treatment outcomes of congenital cholesteatoma of middle ear (CCME). Methods This is a retrospective review of 10 CCME cases selected from 952 cholesteatoma cases treated between January 1995 and December 2005 at the Department of Otolaryngology-Head and Neck Surgery, Chinese PLA General Hospital. The main outcome measures were the site of origin, clinical features, surgical findings, imaging characteristics and hearing results. Results The mean age of the 10 patients was 16 years(ranged from 10 to 24 years), with 6 being older than 18 years. There were 7 males and 3 females. The average delay to diagnosis was longer than 2 years. The mean preoperative PTA was 55 dB HL, with a mean ABG of 45 dB. Typical cholesteatomas were seen behind the tympanic membrane in the superoposterior quadrant on otoscopy only in 2 patients. High resolution CT was completed in all patients. Most of the patients(8/10) were diagnosed with otosclerosis or ossicular abnormality before operation. All patients underwent a one-stage tympanoplasty following transmeatal explorative tympanotomy and complete cholesteatoma removal, except one, who underwent a CWU mastoidectomy due to extensive cholesteatoma involvement. The choleasteatoma lesion was confined to the superoposterior mesotympanum in all patients. The mean postoperative PTA was 20 dB HL. All patients were followed-up for at least 1.5 years postoperatively. Revision procedures were performed in 2 patients for hearing deterioration. No residual or recurrence of cholesteatoma was found. Conclusion CCME is a rare disease that often gets delayed diagnosis. Residual lesions and the prognosis mainly depend on the extent of the lesion.

ObjectiveTo investigate the early change of cochlear ribbon synapses on inner hair cells in response to aminoglycoside ototoxicity.MethodsC57BL/6J mice received intraperitoneal injection of gentamicin (100 mg/kg/day), and the apical coil organ of Corti was examined on the 4th, 7th and 10th day (n=10). Littermates without gentamicin treatment served as controls (n=10). RIBEYE on the presynaptic membrane and AMPA receptors on the postsynaptic membrane were labeled with CtBP2 or GluR2/3 respectively. Three dimension reconstruction was conducted using the 3DS MAX 8.0 software.ResultsThere were no disruptions of outer or inner hair cells in all groups. However, the number of ribbon synapses on cochlear inner hair cells increased significantly within 7 days after gentamicin exposure (P

Objective: To establish an animal model of like-auditory neuropathy in neonatal rat. Methods The animals were injected with phenylhydrazine hydrochloride or saline at 7-day of age. ABR and DPOAE were performed to assess the auditory function. The cochlea basilar membrane stretched preparation and cochlear frozen sections were prepared for immunohistochemical staining to examine the morphological change of hair cells and spiral ganglion cells (SGNs). Results At 7-day age the ABR waveI, III, V, latencies andI- III,I-V IWIs in the experimental group were significantly prolonged compared with those in the control group. The ABR thresholds were also elevated in the experimental group. We found there is no significant difference in DPOAE in phenylhydrazine hydrochloride exposure group compare to control group. The cochlear hair cells showed no signs of loss in both group, but the total number of neurofilaments positive cells in SGNs were significantly reduced in the phenylhydrazine treated animals. Conclusion Our study suggests that phenylhydrazine hydrochloride can change the auditory function and induce peripheral nerve pathology by targeted mainly the SGNs in neonatal rat.

Objective To study presynaptic alternations of cochlear ribbons arising from aminoglycoside ototoxic stimuli in C57BL/6J mice. Methods Animals were injected with low dose gentamicin (100 mg/kg/day) for 14 days, From the 14th to 28th days, the mice were maintained free of gentamicin treatment. Immunohistochemistry labeling was employed to trace RIBEYE, a major presynaptic componment of ribbon synapses. RIBEYE/CtBP2 expression levels were assessed and compared with hearing threshold shifts. Auditory function was assessed by auditory brainstem responses. The stereocilia of outer hair cells (OHCs) and IHCs was examined by scanning electron microscopy (SEM). Results Hearing thresholds were elevated with peak hearing loss observed on the 7th day after gentamicin exposure, followed by improvement after the 7th day. RIBEYE/CtBP2 expression directly correlated with observed hearing threshold shifts. Strikingly, we did not see any obvious changes in stereocilia in both OHCs and IHCs until the 28th day. Mild changes in stereocilia were only observed in OHCs on the 28th day. Conclusions These findings indicate that presynapse cochlear ribbons, rather than stereocilia, may be sensitive to aminoglycoside ototoxic exposure in mice cochleae. A pattern of RIBEYE/CtBP2 expression changes seems to parallel hearing threshold shifts and suggests presynaptic response properties to lower dosage of aminoglycoside ototoxic stimuli.

Objective To evaluate the current status of clinical studies on diagnosis and treatment of sudden deafness (SD) in China by retrospective reviewing articles on SD published in Chinese journals in the past 5 years. Special attention is given to whether the diagnosis and treatment standards established in 1996 by the otolaryngology branch of Chinese Medical Association (the"1996 standard") were followed. Methods The terms of “Sudden deafness” and “treatment” were used as the keywords in searching articles published between 2000 and 2004 in the Chinese biomedicine literature database and Chinese journal network. Principles of evidence-based medicine were applied in reviewing the articles. Results Two hundreds and thirty- four articles were identified, including 176 between 2000 and 2002 and 58 between 2003 and 2004. Among the 176 articles published between 2000 and 2002, effects of medications were studies in 126 articles, of which only 26 (20.6%) followed the"1996 standards". Eighty-nine (70.6%) were reported based on controlled clinical trials (CCT) and 36 (28.5%) met the criteria of randomized controlled trails (RCT). Of the 58 articles published between 2003 and 2004, drug effects were evaluated in 25 articles, which were all based on the “1996 standards". However, there lacked placebo control, follow-up data or statistical analysis in these papers. Only 6 articles reported side-effects from pharmacological treatment. Conclusions While a significant number of articles on SD were published in the past 5 years, the “1996 standards” were followed only in a small number of them. The standards may not be appropriate in guiding research and need to be modified for improved guidance to SD management. Multi-center, RCTs should be a crucial part in studies on SD.