Increased inner ear susceptibility to noise injury in mice with streptozotocin-induced diabetes.

We aimed to investigate the pathophysiology of diabetes-associated hearing impairment in type 1 diabetes using mice with streptozotocin-induced diabetes (C57BL/6J; male). Hearing function was evaluated 1, 3, and 5 months after induction of diabetes (five diabetic and five control animals per time point) using auditory-evoked brain stem responses (ABRs). Mice (four diabetic and four control) were exposed to loud noise (105 dB) 5 months after induction of diabetes. ABRs were measured before and after noise exposure. Cochlear blood flows were measured by laser-Doppler flowmeter. Spiral ganglion cells (SGCs) were counted. Vessel endothelial cells were observed by CD31 immunostaining. Chronologic changes in the ABR threshold shift were not significantly different between the diabetic and control groups. However, vessel walls in the modiolus of the cochleae were significantly thicker in the diabetic group than the control group. Additionally, recovery from noise-induced injury was significantly impaired in diabetic mice. Reduced cochlea blood flows and SGC loss were observed in diabetic mice cochleae after noise exposure. Our data suggest that diabetic cochleae are more susceptible than controls to loud noise exposure, and decreased cochlear blood flow due to sclerosis of the vessels and consequent loss of SGCs are possible mechanisms of hearing impairment in diabetic patients.

Vestibular dysfunction and compensation after removal of acoustic neuroma.

OBJECTIVE: To evaluate vestibular function after unilateral acoustic neuroma surgery via a retrosigmoid approach. METHODS: Thirty-eight patients were tested using caloric irrigation, static posturography, and the Dizziness Handicap Inventory (DHI) before, and one week to nine months after surgery. RESULTS: Twenty-six patients were categorized as a response group and 12 as a no-response group on the basis of preoperative caloric irrigation findings. The posturographic parameters and DHI scores at one week after surgery showed significant deterioration in the response group, but not in the no-response group. However, they recovered to the preoperative baseline at 3 months after surgery. The posturographic parameters and DHI scores for older patients tended to be worse than those for younger patients at 6 and 9 months after surgery. CONCLUSION: Patients in whom caloric responses are retained preoperatively show a temporary disturbance of balance after removal of acoustic neuroma. Disequilibrium after surgery ameliorates to the preoperative baseline within three months due to vestibular compensation, regardless of preoperative vestibular function. It is possible that poorer vestibular compensation may facilitate incomplete recovery in older patients after surgery.

Near-infrared spectroscopy of orbitofrontal cortex during odorant stimulation.

BACKGROUND: For olfaction, several studies have reported near-infrared spectroscopy (NIRS) signal changes in the orbitofrontal cortex (OFC) during odor stimulation. However, the roles of human OFC in olfactory cognition are less well understood. This study was designed to better understand the roles of OFC for olfaction. METHODS: Hemodynamic responses for phenyl ethyl alcohol or citral in the OFCs were measured with NIRS. After the experiment, participants were asked to describe the characteristics of the odor and to rate odor intensity and hedonic valence. RESULTS: Statistical analysis of all participants' data showed significant changes in the concentration of total hemoglobin in the left OFC during the trial (p = 0.04). The total hemoglobin signal increased significantly in the right OFC (p = 0.0008) of the participants who successfully identified the odorant stimulus. CONCLUSION: Our findings showed that NIRS combined with a questionnaire is a useful method for studying the functional neuroanatomy of OFC in terms of olfaction.

Blowing ratio as an evaluation tool for velopharyngeal function after oral and oropharyngeal cancer resection.

BACKGROUND: Our objective was to evaluate the value of the blowing test to measure the speech and swallowing function after resection of oral or oropharyngeal cancer. METHODS: Speech and swallowing functions of the patients after surgical resection of oral or oropharyngeal cancer were assessed by a speech intelligibility test, blowing time, questionnaires, and oropharyngeal pressures. Blowing time (pressure) ratio was determined by dividing blowing time (pressure) with open nose by blowing time (pressure) with closed nose. RESULTS: Blowing time ratio had significant correlation with blowing pressure ratio (p = .014), score of speech intelligibility test (p = .0014), questionnaire for aspiration (p = .029), nasopharyngeal backflow (CC = 0.676, p = .032), amount of food to swallow (p = .037), and oropharyngeal pressure during swallowing (p = .024). CONCLUSION: The present results demonstrated the value of blowing time ratio as a simple objective tool for speech and swallowing ability related to velopharyngeal function after resection of oral and oropharyngeal cancers.

Risk factors for recurrence of benign paroxysmal positional vertigo.

OBJECTIVE: To assess the results of treatment for a first episode of benign paroxysmal positional vertigo (BPPV) and risk factors for recurrence. STUDY DESIGN: Retrospective chart review of 148 BPPV patients at a tertiary care referral centre. MATERIALS AND METHODS: The canalith repositioning procedure (CRP) was performed until vertigo and nystagmus were resolved. Using multivariate logistic regression, we estimated the relationship between the rate of BPPV recurrence within 1 year and various risk factors for BPPV. RESULTS: Among the 145 patients after successful manoeuvre or spontaneous resolution, BPPV recurred in 31 patients (21%) within 1 year. Patients with recurrent BPPV in the posterior semicircular canal required more CRP sessions and a longer period. The rate of BPPV recurrence in patients with endolymphatic hydrops (75%) was significantly higher than in those without (odds ratio 17; 95% confidence interval 2.9-101). Both the first episode of BPPV and recurrent BPPV affected the same ear associated with endolymphatic hydrops in all patients with this complication. CONCLUSIONS: Our data suggest that endolymphatic hydrops is a risk factor for recurrence of BPPV and that prevention of recurrent BPPV is important for control of endolymphatic hydrops.

A paranasal tumor associated with tumor-induced osteomalacia.

BACKGROUND: Tumor-induced osteomalacia (TIO) is an extremely rare paraneoplastic syndrome associated with mesenchymal tumors in the craniofacial region. METHODS: We treated a 24-year-old Japanese woman with paranasal sinus tumor and a low serum phosphate level who presented with nasal obstruction and systemic bone fractures. Serum fibroblast growth factor 23 (FGF-23) was measured before and after surgery. RESULTS: After surgery, her symptoms were resolved and the serum phosphate and FGF-23 levels became normalized. CONCLUSION: FGF-23 is thought to be a useful diagnostic marker in patients with craniofacial tumors associated with multiple systemic fractures.

Microscopic polyangiitis histologically confirmed by biopsy from nasal cavity and paranasal sinuses: a case report.

Microscopic polyangiitis (MPA) is a systemic necrotizing vasculitis affecting small vessels without necrotizing granulomatous inflammation and is commonly associated with necrotizing glomerulonephritis. Diagnosis is based on typical clinical features, the presence of antimyeloperoxidase-antineutrophil cytoplasmic antibodies (MPO-ANCA), and histopathologic findings. Cases of pathologically proven small-vessel vasculitis in nasal biopsy specimens are sparse. Here we report a patient with MPA that was histopathologically confirmed by nasal and paranasal biopsy. A 67-year-old man presented with fever and general fatigue. Laboratory examinations showed severe inflammation and acute progressive renal failure. The serum MPO-ANCA level was elevated. The patient also had nasal polyps that seemed to be nonspecific chronic sinusitis. To obtain a pathologic diagnosis, bilateral ethmoidectomy and nasal polypectomy were performed. Pathological findings revealed vasculitis of small vessels in the mucosal surface. MPA was diagnosed on the basis of clinical symptoms, elevated MPO-ANCA and the pathological findings of the nasal and paranasal surgical specimen.

A novel mitochondrial mutation, 1556C --> T, in a Japanese patient with streptomycin-induced tinnitus.

OBJECTIVE: Aminoglycoside antibiotics are associated with ototoxicity. The 1555A --> G mutation in the 12S ribosomal RNA gene of mitochondrial DNA has been considered to be associated with susceptibility to aminoglycoside antibiotics. In this study we examined a 79-year-old Japanese patient with a 45-year history of streptomycin-induced tinnitus in an attempt to find a mitochondrial mutation. MATERIALS AND METHODS: DNA was extracted from the patient's leukocytes. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) screening for the 1555A --> G mutation was done in order to detect a mitochondrial mutation and then nucleotide sequencing analysis was performed to identify the mutation. RESULTS: PCR-RFLP screening detected the presence of a mitochondrial mutation in the patient. However, the nucleotide sequencing analysis showed that the mutation was not the 1555A --> G mutation but a novel mutation, 1556C --> T. The mutation was not found in 112 unrelated Japanese control subjects, suggesting that the mutation was specific to our patient. CONCLUSIONS: The 1556C --> T mutation may be a genetic risk factor for aminoglycoside-induced hearing impairment. Our result also suggests that patients with the 1556C --> T mutation exist among those expected to have the 1555A --> G mutation as a result of PCR-RFLP analysis.

Synovial sarcoma of the neck.

BACKGROUND: Synovial sarcoma is a soft tissue sarcoma rarely seen in the head and neck. Due to its rarity and morphologic variations, diagnosis is difficult in most cases. METHOD: A case of synovial sarcoma arising in the upper neck is presented. The detection of the specific chromosomal translocation t(X;18)(p11.2;q11.2) is also described. RESULT: A specific chimeric gene, the SSX-SYT fusion gene, was identified in the formalin-fixed paraffin-embedded surgical specimen using the reverse-transcription polymerase chain reaction (RT-PCR) technique. CONCLUSION: Synovial sarcoma contains a characteristic chromosomal translocation, which serves as a useful diagnostic tool. RT-PCR technique has enabled to detect this specific translocation not only in fresh tissues but also in archival paraffin-embedded specimens.

Multiple primary pleomorphic adenomas in a single parotid gland: report of a new case.

The development of multiple primary pleomorphic adenomas in a single parotid gland is extremely rare in previously untreated patients, as only nine cases have been previously reported. In this article, we report the tenth such case, which occurred in an 87-year-old Japanese women. We also report the results of our 7-plus-year review of the types of parotid tumors seen at our institution. We identified 98 tumors in 89 patients; pleomorphic adenomas were the most common tumors, accounting for 45.9% of the total.