Ayako Inoshita

Postnatal development of the organ of Corti in dominant-negative Gjb2 transgenic mice.

Hereditary hearing loss is one of the most prevalent inherited human birth defects, affecting one in 2000. A strikingly high proportion (50%) of congenital bilateral nonsyndromic sensorineural deafness cases have been linked to mutations in the GJB2 coding for the connexin26. It has been hypothesized that gap junctions in the cochlea, especially connexin26, provide an intercellular passage by which K(+) are transported to maintain high levels of the endocochlear potential essential for sensory hair cell excitation. We previously reported the generation of a mouse model carrying human connexin26 with R75W mutation (R75W+ mice). The present study attempted to evaluate postnatal development of the organ of Corti in the R75W+ mice. R75W+ mice have never shown auditory brainstem response waveforms throughout postnatal development, indicating the disturbance of auditory organ development. Histological observations at postnatal days (P) 5-14 were characterized by i) absence of tunnel of Corti, Nuels space, or spaces surrounding the outer hair cells, ii) significantly small numbers of microtubules in inner pillar cells, iii) shortening of height of the organ of Corti, and iv) increase of the cross-sectional area of the cells of the organ of Corti. Thus, morphological observations confirmed that a dominant-negative Gjb2 mutation showed incomplete development of the cochlear supporting cells. On the other hand, the development of the sensory hair cells, at least from P5 to P12, was not affected. The present study suggests that Gjb2 is indispensable in the postnatal development of the organ of Corti and normal hearing.

Noninvasive in vivo delivery of transgene via adeno-associated virus into supporting cells of the neonatal mouse cochlea.

There are a number of genetic diseases that affect the cochlea early in life, which require normal gene transfer in the early developmental stage to prevent deafness. The delivery of adenovirus (AdV) and adeno-associated virus (AAV) was investigated to elucidate the efficiency and cellular specificity of transgene expression in the neonatal mouse cochlea. The extent of AdV transfection is comparable to that obtained with adult mice. AAV-directed gene transfer after injection into the scala media through a cochleostomy showed transgene expression in the supporting cells, inner hair cells (IHCs), and lateral wall with resulting hearing loss. On the other hand, gene expression was observed in Deiters cells, IHCs, and lateral wall without hearing loss after the application of AAV into the scala tympani through the round window. These findings indicate that injection of AAV into the scala tympani of the neonatal mouse cochlea therefore has the potential to efficiently and noninvasively introduce transgenes to the cochlear supporting cells, and this modality is thus considered to be a promising strategy to prevent hereditary prelingual deafness.

Cochlear outer hair cells in a dominant-negative connexin26 mutant mouse preserve non-linear capacitance in spite of impaired distortion product otoacoustic emission

Mutations in the connexin26 gene (GJB2) are the most common genetic cause of congenital bilateral non-syndromic sensorineural hearing loss. Transgenic mice were established carrying human Cx26 with the R75W mutation that was identified in a deaf family with autosomal dominant negative inheritance [Kudo T et al. (2003) Hum Mol Genet 12:995-1004]. A dominant-negative Gjb2 R75W transgenic mouse model shows incomplete development of the cochlear supporting cells, resulting in profound deafness from birth [Inoshita A et al. (2008) Neuroscience 156:1039-1047]. The Cx26 defect in the Gjb2 R75W transgenic mouse is restricted to the supporting cells; it is unclear why the auditory response is severely disturbed in spite of the presence of outer hair cells (OHCs). The present study was designed to evaluate developmental changes in the in vivo and in vitro function of the OHC, and the fine structure of the OHC and adjacent supporting cells in the R75W transgenic mouse. No detectable distortion product otoacoustic emissions were observed at any frequencies in R75W transgenic mice throughout development. A characteristic phenotype observed in these mice was the absence of the tunnel of Corti, Nuels space, and spaces surrounding the OHC; the OHC were compressed and squeezed by the surrounding supporting cells. On the other hand, the OHC developed normally. Structural features of the lateral wall, such as the membrane-bound subsurface cisterna beneath the plasma membrane, were intact. Prestin, the voltage-dependent motor protein, was observed by immunohistochemistry in the OHC basolateral membranes of both transgenic and non-transgenic mice. No significant differences in electromotility of isolated OHCs during development was observed between transgenic and control mice. The present study indicates that normal development of the supporting cells is indispensable for proper cellular function of the OHC.

Vestibular function of patients with profound deafness related to GJB2 mutation

Abstract Conclusion: GJB2 mutations are responsible not only for deafness but also for the occurrence of vestibular dysfunction. However, vestibular dysfunction tends to be unilateral and less severe in comparison with that of bilateral deafness. Objectives: The correlation between the cochlear and vestibular end-organs suggests that some children with congenital deafness may have vestibular impairments. On the other hand, GJB2 gene mutations are the most common cause of nonsyndromic deafness. The vestibular function of patients with congenital deafness (CD), which is related to GJB2 gene mutation, remains to be elucidated. The purpose of this study was to analyze the relationship between GJB2 gene mutation and vestibular dysfunction in adults with CD. Methods: A total of 31 subjects, including 10 healthy volunteers and 21 patients with CD, were enrolled in the study. A hearing test and genetic analysis were performed. The vestibular evoked myogenic potentials (VEMPs) were measured and a caloric test was performed to assess the vestibular function. The percentage of vestibular dysfunction was then statistically analyzed. Results: The hearing level of all CD patients demonstrated a severe to profound impairment. In seven CD patients, their hearing impairment was related to GJB2 mutation. Five of the seven patients with CD related to GJB2 mutation demonstrated abnormalities in one or both of the two tests. The percentage of vestibular dysfunction of the patients with CD related to GJB2 mutation was statistically higher than in patients with CD unrelated to GJB2 mutation and in healthy controls.

Bacteriology of recurrent exacerbation of postoperative course in chronic rhinosinusitis in relation to asthma.

OBJECTIVES Co-mobidity of asthma is known to result in a poor prognosis of post-endoscopic sinus surgery (post-ESS). Bacterial infection may play a key role in recurrent pathophysiology of sinusitis in post-ESS. METHODS Forty-two patients with CRS associated with asthma undergoing ESS were enrolled. Bacterial culture was performed from the sinus cavity at the time of acute infectious episodes. Recurrence of sinonasal disease was analyzed in terms of steroid responsiveness and peak expiratory flow (PEF). RESULTS Totally 75 aspirates were obtained during post-ESS; 2 repeat aspirates from 10 patients, 3 from 5 patients, and 4 from 2 patients. Only 6 specimens (8.0%) obtained from 5 patients (11.9%) showed no growth whereas 83 isolates were recovered from 69 specimens. Sixteen patients had at least one episode of a significant decline of PEF. All except one patient complained of symptoms and signs of upper respiratory infections prior to a depression of PEF. Positive culture was obtained in 10 out of 11 patients examined at the time of acute exacerbation of CRS. CONCLUSION Bacterial infection may play a critical role of recurrent polyps and refractory symptoms during post-ESS follow-up. Moreover, worsening of sinusitis accompanies asthma exacerbation.

Gene transfer targeting mouse vestibule using adenovirus and adeno-associated virus vectors.

Hypothesis The present study assessed how to inject a gene into the mouse vestibule and which is the optimum gene to the mouse vestibule adenovirus (AdV) vector or adeno-associated virus (AAV) vector. Background Loss of vestibular hair cell is seen in various balance disorder diseases. There have been some reports concerning gene delivery to the mouse vestibule in recent years. To effectively induce transgene expression at the vestibule, we assessed the efficiency of inoculating the mouse inner ear using various methods. Methods We employed an AdV- and AAV-carrying green fluorescent protein using a semicircular canal approach (via a canalostomy) and round window approach. Results AAV injection via canalostomy induced gene expression at the hair cells, supporting cells, and fibrocytes at the vestibular organs without auditory or balance dysfunction, suggesting it was the most suitable transfection method. This method is thus considered to be a promising strategy to prevent balance dysfunction. Conclusion AAV injection via canalostomy to the vestibule is the noninvasive and highly efficient transfection method, and this study may have the potential to repair balance disorders in human in the future.

An immunohistochemical study of sinonasal hemangiopericytoma

We present herein the imaging and pathological features of a 28-year-old male with a sinonasal hemangiopericytoma-like tumor occupying the left nasal meatus. At the initial visit, a nasal polyp was suspected, but, as the patient was bleeding readily, an angiomatoid lesion was also regarded as a possible diagnosis. Based on a thorough histopathological analysis, a sinonasal hemangiopericytoma-like tumor was diagnosed. Hematoxylin and eosin staining also showed a mild degree of nuclear pleomorphism and a slight increase in mitotic activity, and immunohistochemical studies using anti-CD34, MIB-1, and Vimentin antibodies were useful for distinguishing the hemangiopericytoma-like tumor from true hemangiopericytoma and a solitary fibrous tumor.

Effects of olmesartan on blood pressure and insulin resistance in hypertensive patients with sleep-disordered breathing.

The increased risk of cardiovascular morbidity and mortality among patients with sleep-disordered breathing (SDB) has been linked to arterial hypertension and insulin resistance. However, an effective antihypertensive agent for patients with SDB has not been identified. We investigated the effect of the angiotensin II subtype 1 receptor blocker olmesartan in hypertensive patients with SDB. This prospective, one-arm pilot study included 25 male patients with untreated SDB (mean age, 52.7 ± 11.4 years). We measured blood pressure, oxygen desaturation index (ODI), cardiac function using echocardiography, and insulin resistance using the homeostasis model assessment (HOMA) before and after 12 weeks of olmesartan therapy (mean dose, 17.6 ± 4.4 mg/day). Olmesartan significantly decreased systolic blood pressure (151.4 ± 8.0 vs 134.0 ± 7.4 mmHg; P < 0.001), diastolic blood pressure (93.4 ± 7.1 vs 83.9 ± 6.3 mmHg; P < 0.001), and HOMA index (3.7 ± 2.9 vs 2.8 ± 1.9; P = 0.012). Furthermore, left ventricular ejection fraction significantly increased at 12 weeks (68.1 ± 5.1 vs 71.6 ± 5.4%; P = 0.009). However, body mass index (BMI) and degree of SDB did not change (BMI, 26.6 ± 4.0 vs 26.6 ± 4.2 kg/m2, P = 0.129; 3% ODI, 29.5 ± 23.1 vs 28.2 ± 21.0 events/h, P = 0.394). Olmesartan significantly reduced blood pressure and insulin resistance in hypertensive patients with SDB without changing BMI or SDB severity.

Novel use of a Weerda laryngoscope for transoral excision of a cervical ganglioneuroma: a case report

IntroductionA ganglioneuroma is a benign neoplasm arising from neural crest cells of the sympathetic nerve fibers and is most commonly seen in the posterior mediastinum or retroperitoneum. Although very uncommon, ganglioneuromas must be included in the differential diagnosis of neck masses. In young adult women, neck incisions made for excision of these benign tumors should be avoided whenever possible.Case presentationWe herein describe the case of a 19-year-old Japanese woman with a ganglioneuroma. The tumor was found in the parapharyngeal space, an unusual location. A fine-needle aspiration biopsy was performed but was considered inadequate to make a definitive diagnosis, so the asymptomatic lesion was surgically excised using a Weerda laryngoscope. The lesion measured 4 × 3 cm in size and was encapsulated. A pathological analysis showed the presence of two distinct cell types, ganglion cells and Schwann cells, embedded in a loose myxoid stroma. The final diagnosis was a ganglioneuroma.ConclusionA complete excision was made possible by using a transoral approach with a novel use of the Weerda laryngoscope. Although its applicability to specific cases depends on the location, size and nature of the tumor, we believe that the Weerda laryngoscope will continue to be useful for performing transoral surgery for cervical tumors.

A randomized prospective study of oral levofloxacin vs intravenous flomoxef prophylaxis in postoperative infection after endoscopic sinus surgery

OBJECTIVE The clinical efficacy and cost effectiveness of oral antimicrobial prophylaxis with levofloxacin (LVFX) on endoscopic sinus surgery (ESS) was evaluated. MATERIALS AND METHODS Ninety-three patients undergoing ESS were prospectively enrolled in the present study. The patients were randomly divided into 2 groups, LVFX and flomoxef (FMOX). Two hundred milligrams of LVFX was orally given 2 hours before the start of surgery and 6 hours after the end of surgery, which was followed by the administration of 200 mg every 12 hours for 2 days. One gram of FMOX was dissolved in 100 ml of physiological saline and given intravenously at the induction of anesthesia and 6 hours after the end of surgery, followed by infusion twice daily for 2 days. RESULTS There were no statistically significant differences between 2 groups in terms of age, sex, systemic complications, surgical procedures, the duration of the operation, the length of hospitalization, the amount of blood loss, body temperature, or the number of white blood cells or C-reactive protein. Although no statistical significance was observed in the bacterial resistance between the two antibiotics, LVFX seems to show a low rate of resistance pattern change as compared to FMOX. The present study demonstrated that no patients treated with LVFX or FMOX were afflicted with postsurgical infection. CONCLUSION Oral administration of LVFX is a simple, cost-effective and safe alternative to intravenous prophylaxis in ESS based on clinical efficacy and bacteriological study.