The diagnostic value of measurement of cochlear length and height in temporal bone CT multiplanar reconstruction of inner ear malformation.

CONCLUSION: The cochlear length (CL) and cochlear height (CH) measured through MPR will provide for more accurate quantitative diagnosis of inner ear malformation, and are subsequently convenient for calculating cochlear duct length (CDL) before cochear implant. OBJECTIVES: Qualitative and quantitative diagnosis of inner ear malformation in deaf patients through multiplanar reconstruction (MPR) was performed to provide a reference for cochlear implants. METHODS: One hundred and two cases without sensorineural deafness and 560 patients with sensorineural deafness had MPR of temporal bone computed tomography performed to obtain the standardized cochlear-view and oblique coronal-view images. The inner ear radial lines were measured to formulate normal values for inner ear malformation diagnosing, and the CDL was estimated based on CL. RESULTS: The normal range values of inner ear radial lines were measured and formulated, of which CL was 8.1-9.59 mm and CH was 3.28-3.90 mm. According to inner ear morphology and the normal values measured above, 61 cases of incomplete partition-type II (IP-II) and a high percentage (27/110, 24.5%) of hypoplasia of cochlea (HC) were diagnosed. The HC group was further divided into 1-turn, 1.5-turn, and 2-turn sub-groups, which had CDL of 15.98 ± 1.48 mm, 21.36 ± 0.96 mm, and 26.56 ± 0.60 mm, respectively.

Electrophysiological change in the tensor veli palatini muscle after radiotherapy.

CONCLUSION: Electromyography of the tensor veli palatine (TVP) was abnormal and showed mainly myogenic impairment in patients with nasopharyngeal carcinoma (NPC) with secretory otitis media (SOM) after radiotherapy. The diseased ears showed impairment in opening functions of the eustachian tubes (ETs). OBJECTIVES: To characterize electrophysiology of the TVP muscle using electromyography (EMG) in patients with SOM after radiotherapy of NPC. METHODS: Twenty healthy volunteers and 20 patients with NPC and SOM after radiotherapy were chosen for assessment of EMG of the TVP during swallowing. RESULTS: The measurements of average duration and amplitude of action potential, swallowing contraction duration, and peak voltage in NPC patients with both SOM (n = 25) and healthy ears (n = 6) were significantly lower than those of ears (n = 38) in healthy controls (p < 0.01). In patients with NPC, the average action potential duration and swallowing contraction duration in ears with SOM were lower than those of subjects with healthy ears (p < 0.05), whereas no significant difference was found in average amplitude of action potential and peak voltage between them.

[Protective effects of N-acetylcysteine on cochlear damage occur in guinea pigs exposed to irradiation].

OBJECTIVE: To explore the protective effects of N-acetylcysteine (NAC) on cochlear damage occurring in irradiated guinea pigs. METHODS: Seventy-two guinea pigs were randomly divided into 4 groups (n = 18 each). Control group received neither NAC nor irradiation, irradiation group received total cranium irradiation of 70 Gy, irradiation & saline group cranium irradiation of 70 Gy and saline solution through a round window and NAC group cranium irradiation of 70 Gy and NAC through a round window. The right ear received radiation. The animals were sacrificed at Day 14 post-irradiation. The specimens were dehydrated, embeded in paraffin and serially cut into 5-µm slices. Sections were stained with immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL). The cochlear basal membranes were observed for malondialdehyde (MDA) and superoxide dismutase (SOD) with scanning electron microscope. RESULTS: The cilium of hair cells had no clear loss and apoptotic number of spiral ganglion cells decreased in NAC group. The average optical density value of Caspase 3 in spiral ganglion in NAC group significantly decreased versus the irradiation group (0.08 ± 0.02 vs 0.10 ± 0.01, P < 0.01). The level of MDA of NAC group also decreased versus the irradiation group (0.33 ± 0.05 vs 0.84 ± 0.13, P < 0.05). The level of SOD in the NAC group increased versus the irradiation group (10.7 ± 3.0 vs 8.7 ± 1.3, P < 0.05). The ratio of apoptotic cell in SGC in the NAC group at Day 14 (7.8% ± 1.8%) decreased versus the irradiation group (32.0% ± 8.7%) at Day 14. CONCLUSION: MDA and SOD may be involved in the pathogenesis of cochlear cell damage. And NAC protects the irradiated cochlear cell.

[Analysis of sniffing test in otitis media with effusion].

OBJECTIVE: To explore the roles of the closure disorder of Eustachian tube in occurrence and development of otitis media with effusion (OME). METHODS: Fifty-six adults with OME, 16 children with OME, 66 health adults and 20 health children were selected according to diagnosis criteria. Sniffing test was measured by Tubo-tymanoaerodynamic graphy and the self-designed questionnaires were surveyed in all cases. RESULTS: The positive levels in sniffing test were regarded as external auditory canal press 10dapa lower than baseline of the pressure. The positive rate was 64.86% in adults with OME, which was higher than health adults (P < 0.01). The positive rate was 70.83% in children with OME which was higher than health children (P < 0.05). CONCLUSIONS: The higher positive rate of sniff test in OME patients suggests that closure disorder in Eustachian tube playing an important role in the occurrence and development of OME.

Salicylate initiates apoptosis in the spiral ganglion neuron of guinea pig cochlea by activating caspase-3.

Salicylate-induced ototoxicity leading to sensorineural hearing loss (SNHL) and tinnitus is well documented. However, the exact mechanisms are poorly defined. Caspase-3 is a member of the class of effector caspases and has been activated in nearly every model of apoptosis. To examine its role in salicylate-induced injury, we subjected guinea pigs to treatment with a specific inhibitor zDEVD-FMK via the round window niche (RWN) followed by a systemic injection of salicylate at a dose of 200 mg · kg(-1) · d(-1) i.p. for 10 consecutive days. For those animals administered with salicylate, immunohistochemical studies revealed that caspase-3 was activated in the spiral ganglion neurons (SGNs) and method of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) to identify neuronal apoptosis showed that fragmented nuclei were distributed in Rosenthal's canal. Topical administration of the zDEVD-FMK at a concentration of 500 mM blocked caspase-3 activation and had an effect in reducing the number of TUNEL-positive auditory neurons. In contrast, the inhibitor at a concentration of 125 or 250 mM caused no variation in the expression of activated caspase-3, or in the ratio of TUNEL-positive neurons. These results indicate that caspase-3 is a crucial mediator of apoptosis induced by salicylate in the primary auditory neuron in vivo, and suggest that the specific inhibitor at a relatively high concentration may be therapeutically beneficial in salicylate-induced apoptosis.

Caspase-3 activation in the guinea pig cochlea exposed to salicylate.

In the current study, we explored whether chronic salicylate exposure could induce apoptosis in outer hair cells (OHCs) and spiral ganglion neurons (SGNs) of the cochlea. Guinea pig received sodium salicylate (400 mg/kg/d) or saline vehicle for 10 consecutive days. Programmed cell death (PCD) executioner was evaluated with immunohistochemistry detection of activated caspase-3. Apoptosis was examined with a terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method. Repeated salicylate administration activated caspase-3 and caused apoptosis in OHCs and SGNs (p<0.01 vs. saline control for both measures and in both cell types). Cell counting showed a significant loss in OHCs (p<0.01 vs. saline control), but not in inner hair cells (IHCs). Transmission electron microscopy (TEM) revealed chromatin condensation and nucleus margination in salicylate-treated cochlea. Scanning electron microscopy (SEM) demonstrated stereociliary bundles breakdown and fusion at the apical of OHCs, villous matter was discovered to attach on the surface of SGNs. These findings suggest that long-term administration of high-dose salicylate can activate caspase-3 pathway to induce OHC and SGN apoptosis.

[Effect of sodium salicylate on the auditory brain stem response threshold and expression of glutamic acid decarboxylase in spiral ganglion of juvenile and adult guinea pigs].

OBJECTIVE: To study the differences of regulation of sodium salicylate on the auditory brain stem response (ABR) threshold and expression of glutamic acid decarboxylase (GAD) protein in spiral ganglion of juvenile and adult guinea pigs. METHODS: Fourty juvenile guinea pigs which were born just four days and fourty adult guinea pigs which were born thirty days were selected. They were divided four groups (group A; group B; group C; group D). ABR threshold was detected before administration, after administration for 15 days and after administration stopped for 30 days. The protein expression of GAD were measured after administration for 15 days and after administration stopped for 30 days by the method of immunohistochemistry. RESULTS: ABR threshold of juvenile sodium salicylate groups (group C) was increased remarkably than that of before administration and the control after administration for 15 days (P < 0.001). ABR threshold of group C was returned to the level of that of before administration and after administration stopped for 30 days. ABR threshold of adult sodium salicylate groups (group D) was increased remarkably than that of before administration and the control after administration for 15 days (P < 0.001). ABR threshold of group D was kept the high level after administration stopped for 30 days. The protein expression of GAD of sodium salicylate groups (group C and D) was decreased than that of the control after administration for 15 days. The protein expression of group C was more visible regression than that of group D (t = 4.7, P < 0.001). The protein expression of group C was returned the level of before administration after administration stopped for 30 days, but the protein expression of group D was kept the high level. CONCLUSIONS: The results suggest that sodium salicylate can regulate differently ABR threshold and expression of GAD protein in spiral ganglion of juvenile and adult guinea pigs. The effects of sodium salicylate on ABR threshold and expression of GAD protein in spiral ganglion of juvenile pigs are more noticeable than that of adult guinea pigs, but these changes are easier to return the normal than that of adult guinea pigs.

[Effects of sodium salicylate on the expressions of gamma-aminobutyricacid and glutamate and auditory response properties of the inferior colliculus neurons].

The effects of sodium salicylate (NaSA) on the expressions of gamma-aminobutyricacid (GABA) and glutamate (Glu), and auditory response properties of the inferior colliculus neurons in mice were studied. Thirty-six Kunming mice were divided into three groups: control group (saline injection); NaSA group (NaSA 450 mg/kg, i.p., each day for 15 d); NaSA + lidocaine group (NaSA 450 mg/kg + lidocaine 10 mg/kg, i.p., each day for 15 d). The expressions of GABA and Glu were examined with immunohistochemical method. The intensity-rate function, intensity-latency function and frequency-tuning curve were determined with extracellular electrophysiological recording. Results are as follows: (1) The expression of GABA in the NaSA and NaSA + lidocaine groups decreased remarkably compared with that in the control group; there was no noticeable difference between the NaSA and NaSA + lidocaine groups. The expression of Glu in the NaSA group increased significantly compared with that in the control and NaSA + lidocaine groups. No difference in the expression of Glu was found between the control and NaSA + lidocaine groups. (2) In NaSA group, the intensity-rate function displayed a non-monotonic pattern, rising at low intensity and descending at high intensity; the tip of frequency-tuning curves became broad after administration of NaSA. (3) The changes in intensity-rate function and intensity-latency function were not evident and the tips of the frequency-tuning curves sharpened in the NaSA + lidocaine group. These results suggest that administration of NaSA increases the expression of Glu-positive neurons and reduces that of GABA-positive neurons in the inferior colliculus. NaSA changes the auditory response properties of the inferior colliculus and lidocaine can reverse these changes.

[Clinical application of incomplete tympanectomy for secretory otitis media in nasopharyngeal carcinoma after radiotherapy].

BACKGROUND & OBJECTIVE: Efficacy of previous treatments on secretory otitis media ears with severely damaged eustachian tube function after radiotherapy is limited. Tympan perforation can avoid relapse of secretory otitis media. This study was to explore clinical value of incomplete tympanectomy for secretory otitis media in patients with nasopharyngeal carcinoma (NPC) after radiotherapy. METHODS: After confirmed severely damaged eustachian tube function through comprehensive examinations, 16 NPC patients (18 ears) with secretory otitis media after radiotherapy received incomplete tympanectomy. All patients were followed up for more than 6 months. RESULTS: After operation, 11 of 18 (61%) ears remained tympan perforation, audition was improved at large in these ears, the average air-bone conduction difference decreased from 30.1 dB to 16.0 dB, other symptoms, such as aural fullness, tinnitus, and headache, basically disappeared. After operation, tympans closed up in 7 (39%) ears,the average air-bone conduction difference decreased from 33.0 dB to 32.1 dB. CONCLUSION: Incomplete tympanectomy may have a long and definite effect on secretory otitis media without any injury on audition after healing of tympan.