Caloric restriction reduces basal cell proliferation and results in the deterioration of neuroepithelial regeneration following olfactotoxic mucosal damage in mouse olfactory mucosa.

The effects of caloric restriction (CR) on cell dynamics and gene expression in the mouse olfactory neuroepithelium are evaluated. Eight-week-old male C57BL/6 mice were fed either control pellets (104 kcal/week) or CR pellets (67 kcal/week). The cytoarchitecture of the olfactory neuroepithelium in the uninjured condition and its regeneration after injury by an olfactotoxic chemical, methimazole, were compared between mice fed with the control and CR diets. In the uninjured condition, there were significantly fewer olfactory marker protein (OMP)-positive olfactory receptor neurons and Ki67-positive proliferating basal cells at 3 months in the CR group than in the control group. The number of Ki67-positive basal cells increased after methimazole-induced mucosal injury in both the control and the CR groups, but the increase was less robust in the CR group. The recovery of the neuroepithelium at 2 months after methimazole administration was less complete in the CR group than in the control group. These histological changes were region-specific. The decrease in the OMP-positive neurons was prominent in the anterior region of the olfactory mucosa. Gene expression analysis using a DNA microarray and quantitative real-time polymerase chain reaction demonstrated that the expression levels of two inflammatory cytokines, interleukin-6 and chemokine ligand 1, were elevated in the olfactory mucosa of the CR group compared with the control group. These findings suggest that CR may be disadvantageous to the maintenance of the olfactory neuroepithelium, especially when it is injured.

Facial nerve paralysis associated with temporal bone masses.

OBJECTIVE: To investigate the clinical and electrophysiological features of facial nerve paralysis (FNP) due to benign temporal bone masses (TBMs) and elucidate its differences as compared with Bell's palsy. METHODS: FNP assessed by the House-Brackmann (HB) grading system and by electroneurography (ENoG) were compared retrospectively. RESULTS: We reviewed 914 patient records and identified 31 patients with FNP due to benign TBMs. Moderate FNP (HB Grades II-IV) was dominant for facial nerve schwannoma (FNS) (n=15), whereas severe FNP (Grades V and VI) was dominant for cholesteatomas (n=8) and hemangiomas (n=3). The average ENoG value was 19.8% for FNS, 15.6% for cholesteatoma, and 0% for hemangioma. Analysis of the correlation between HB grade and ENoG value for FNP due to TBMs and Bell's palsy revealed that given the same ENoG value, the corresponding HB grade was better for FNS, followed by cholesteatoma, and worst in Bell's palsy. CONCLUSIONS: Facial nerve damage caused by benign TBMs could depend on the underlying pathology. Facial movement and ENoG values did not correlate when comparing TBMs and Bell's palsy. When the HB grade is found to be unexpectedly better than the ENoG value, TBMs should be included in the differential diagnosis.

Amblyopia Associated with Congenital Facial Nerve Paralysis.

The association between congenital facial paralysis and visual development has not been thoroughly studied. Of 27 pediatric cases of congenital facial paralysis, we identified 3 patients who developed amblyopia, a visual acuity decrease caused by abnormal visual development, as comorbidity. These 3 patients had facial paralysis in the periocular region and developed amblyopia on the paralyzed side. They started treatment by wearing an eye patch immediately after diagnosis and before the critical visual developmental period; all patients responded to the treatment. Our findings suggest that the incidence of amblyopia in the cases of congenital facial paralysis, particularly the paralysis in the periocular region, is higher than that in the general pediatric population. Interestingly, 2 of the 3 patients developed anisometropic amblyopia due to the hyperopia of the affected eye, implying that the periocular facial paralysis may have affected the refraction of the eye through yet unspecified mechanisms. Therefore, the physicians who manage facial paralysis should keep this pathology in mind, and when they see pediatric patients with congenital facial paralysis involving the periocular region, they should consult an ophthalmologist as soon as possible.

Short-term functional and morphological changes in guinea pig cochlea following intratympanic application of Burow's solution.

OBJECTIVES: Burow's solution, comprising aluminum sulfate and acetic acid, is an otic drug formulation applied to the tympanic cavity. We characterized the relationship between the auditory brain stem response (ABR) thresholds and the area of the capillary basement membrane anionic sites in the stria vascularis after the application of Burow's solution. METHODS: We used cationic polyethylenimine (PEI) to observe changes in the capillary basement membrane anionic sites in the stria vascularis. Burow's solution was dropped directly onto the round window membrane and retained for 2 hours. The ABRs were recorded at 4, 8, and 20 kHz immediately before surgery and before decapitation. The cochlea was extirpated immediately or 2 days after the surgery and immersed in cationic PEI solution. The PEI distribution associated with the capillary basement membrane anionic sites was measured in the basal and third turns. RESULTS: The ABR threshold shifts at 4, 8, and 20 kHz were significantly increased immediately after the surgery, whereas those at 4 and 8 kHz, but not at 20 kHz, had recovered 2 days after the surgery. Further, the PEI distribution was significantly decreased immediately after the surgery and had recovered 2 days after the surgery. CONCLUSIONS: Although Burow's solution may cause an acetic low pH in the stria vascularis and a temporary ABR threshold shift at 4 and 8 kHz, the permanent ABR threshold shift at 20 kHz cannot be attributed to the acetic low pH.

A spontaneous true aneurysm of the superficial temporal artery treated by surgical resection.

An aneurysm of the superficial temporary artery (STA) has a rarer occurrence than intracranial aneurysm. However, traumatic aneurysms of the STA are not unusual and have been reported about more than 400 cases. Most of these were pseudoaneurysms caused by blunt trauma because of the anatomical location of STA. In contrast, spontaneous or non-traumatic aneurysms of the STA are quite rare and only 8 cases of spontaneous true aneurysms in the STA have been reported. Herein, we report a case of a 77-year-old woman, who presented with a preauricular mass showing subacute enlargement over the previous two months. She had no history of head injury. Imaging studies demonstrated that the mass was a saccular type aneurysm accompanied by afferent and efferent vessels. The mass was resected under general anesthesia and there were no symptoms or signs of local circulatory deficiency, nor was there any interference with nerve function after the surgery. Pathological examination showed that the mass was a true aneurysm. The literature is reviewed and the management of the STA aneurysm is discussed.

Comparison of hearing improvement and complications after stapes surgery with and without potassium titanyl phosphate laser for manipulation of the foot plate.

OBJECTIVE: The purpose of the current study was to evaluate the differences in hearing results and complications between the conventional technique (CT) and potassium titanyl phosphate laser (KTP) laser-assisted stapes surgery that does not involve the manipulation of the foot plate. METHODS: Ninety-eight ears with conductive or mixed hearing loss due to otosclerosis were operated on by using the CT or KTP laser-assisted manipulation. The results of pure-tone audiometry, the duration of postoperative vestibular symptoms, and the presence of damage to the foot plate were reviewed retrospectively. RESULTS: The extent of hearing improvement and the duration of vestibular symptoms were not significantly different between the two groups. The damage to the foot plate was significantly less frequent in the KTP group compared to the CT group. Profound sensorineural hearing loss occurred in one case in the CT group, whereas no significant sensorineural hearing loss was detected in the KTP group. CONCLUSIONS: According to our present findings, KTP laser-assisted surgery was safer than CT in terms of the damage to the foot plate even when the KTP laser was not used for opening the foot plate. However, both techniques showed similar results in hearing improvement and vestibular symptoms.

Effect of vitamin C depletion on age-related hearing loss in SMP30/GNL knockout mice.

Using senescence marker protein 30 (SMP30)/gluconolactonase (GNL) knockout (KO) mice, which cannot synthesize vitamin C (VC), we examined whether modulating VC level affects age-related hearing loss (AHL). KO and wild-type (WT) C57BL/6 mice were given water containing 1.5 g/L VC [VC(+)] or 37.5mg/L VC [VC(-)]. At 10 months of age, KO VC(-) mice showed significant reduction in VC level in the inner ear, plasma, and liver, increase in auditory brainstem response (ABR) thresholds, and decrease in the number of spiral ganglion cells compared to WT VC(-), WT VC(+), and KO VC(+) mice. There were no differences in VC level in the inner ear, ABR thresholds, or the number of spiral ganglion cells among WT VC(-), WT VC(+), and KO VC(+) mice. These findings suggest that VC depletion can accelerate AHL but that supplementing VC may not increase VC level in the inner ear or slow AHL in mice.