[Successful treatment of dysphagia due to Wallenberg syndrome using intermittent air stretching method with balloon catheter: a case report].

A 69-year-old woman presented with dysphagia due to Wallenberg syndrome. Videofluorography revealed unilateral dysfunction of the cricopharyngeal muscle, which caused stenosis of the esophageal entrance on the affected side. Pharyngeal fiberscopy indicated that glottal function and the cough reflex were preserved and that the pharyngeal reflex was lost. The stenosis of the esophageal entrance due to dysfunction of the cricopharyngeal muscle on the affected side and the loss of the pharyngeal reflex were considered to cause the patient's dysphagia. Based on above mentioned findings, the intermittent air stretching method with balloon catheter(IASM)was performed. As a result, dysphagia showed rapid improvement without any complications such as aspiration or bleeding. Thus, the IASM may be effective in some cases of dysphagia due to Wallenberg syndrome.

[A case of metastatic salivary duct carcinoma successfully treated with trastuzumab-based targeted therapy].

Salivary duct carcinoma is a malignant salivary neoplasm with a poor prognosis. Effective treatment for remote metastases has not been recognized. We report herein on a case of this tumor overexpressing HER2 successfully treated with trastuzumab-based molecular targeted therapy. The patient was a 69-year-old man, who developed remote metastases into the liver and the thoracic vertebra six months after surgery and postoperative irradiation for the primary and nodal lesions. After targeted therapy including paclitaxel and trastuzumab, these metastatic lesions showed rapid and continued regression. After paclitaxel was discontinued due to peripheral neuropathy in the extremities, trastuzumab monotherapy followed without resulting in cardiotoxicity. After three years since development of remote metastases, the patient is doing well without re-progression of the disease.

Efficient Bone Conduction Hearing Device With a Novel Piezoelectric Transducer Using Skin as an Electrode.

OBJECTIVE: Bone conduction hearing aids are the only non-surgical devices used for conductive hearing loss. However, they are impractical for lifelong use since they require close contact of the transducer with the head skin, causing skin erosion and discomfort. Bone conduction hearing implants and active middle ear implants do not present these issues; however, they require surgery and can sometimes cause issues in the skin surrounding the devices. This study aimed to develop a new bone conduction hearing device that does not exert pressure on the skin or require surgery. METHODS: Our device modified a piezoelectric element by using the skin of a pinna as one of the two electrodes of a conventional piezoelectric device. We compared the sound transmission of a speaker, a conventional piezoelectric device, or the new device to the Guinea pig cochlea, a physiological sound transducer to the auditory nerve, in normal and air-conductive hearing loss conditions. RESULTS: The novel device transmitted sound to the cochlea even after causing air-conductive hearing loss. Its bone conduction was more efficient than the speaker and the conventional piezoelectric device. CONCLUSION: We developed a novel type of bone conduction device that efficiently transmits sound to the cochlea by skipping the external auditory canal, tympanic membrane, and middle ear ossicles. This device does not exert pressure on the skin that can result in skin damage, an adverse effect of a conventional bone conduction hearing aid. SIGNIFICANCE: Our novel hearing device can be used as a substitute for current bone-conduction hearing devices.

Afferent deprivation elicits a transcriptional response associated with neuronal survival after a critical period in the mouse cochlear nucleus.

The mechanisms underlying enhanced plasticity of synaptic connections and susceptibilities to manipulations of afferent activity in developing sensory systems are not well understood. One example is the rapid and dramatic neuron death that occurs after removal of afferent input to the cochlear nucleus (CN) of young mammals and birds. The molecular basis of this critical period of neuronal vulnerability and the transition to survival independent of afferent input remains to be defined. Here we used microarray analyses, real-time reverse transcription PCR, and immunohistochemistry of the mouse CN to show that deafferentation results in strikingly different sets of regulated genes in vulnerable [postnatal day (P)7] and invulnerable (P21) CN. An unexpectedly large set of immune-related genes was induced by afferent deprivation after the critical period, which corresponded with glial proliferation over the same time frame. Apoptotic gene expression was not highly regulated in the vulnerable CN after afferent deprivation but, surprisingly, did increase after deafferentation at P21, when all neurons ultimately survive. Pharmacological activity blockade in the eighth nerve mimicked afferent deprivation for only a subset of the afferent deprivation regulated genes, indicating the presence of an additional factor not dependent on action potential-mediated signaling that is also responsible for transcriptional changes. Overall, our results suggest that the cell death machinery during this critical period is mainly constitutive, whereas after the critical period neuronal survival could be actively promoted by both constitutive and induced gene expression.

Elevation of superoxide dismutase increases acoustic trauma from noise exposure.

The generation of superoxide has been implicated as a cause of cochlear damage from excessive noise. Cu/Zn superoxide dismutase (SOD1) generally will protect against superoxide-mediated tissue injury but protection by this enzyme against noise trauma is controversial. This study assessed auditory function in C57BL/6 mice overexpressing SOD1 or treated with lecithinized SOD1 (PC-SOD1). Noise exposure caused significantly higher threshold shifts in PC-SOD1-treated animals than physiological saline-treated animals. Cochlear tissues of PC-SOD1-treated animals exhibited significant elevation of the levels in the SOD activity, not in the catalase activity, in comparison with those of saline-treated animals. Likewise, transgenic mice overexpressing SOD1 tended to suffer higher threshold shifts than nontransgenic littermates from noise exposure. The findings indicate that increasing SOD1 enhances auditory dysfunction following noise exposure.

Engraftment of embryonic stem cell-derived neurons into the cochlear modiolus.

This study aimed to evaluate the potential of embryonic stem cell-derived neural progenitors for use as transplants for the replacement of the auditory primary neurons, spiral ganglion neurons. Mouse embryonic stem cell-derived neural progenitors were implanted into the base of the cochlear modiolus of normal or deafened guinea pigs, which contains spiral ganglion neurons and cochlear nerve fibers. Histological analysis demonstrated the survival and neural differentiation of transplants in the cochlear modiolus and active neurite outgrowth of transplants toward host peripheral or central auditory systems. Functional assessments indicated the potential of transplanted embryonic stem cell-derived neural progenitors to elicit the functional recovery of damaged cochleae. These findings support the hypothesis that transplantation of embryonic stem cell-derived neural progenitors can contribute to the functional restoration of spiral ganglion neurons.

Nuclear translocation of beta-catenin in developing auditory epithelia of mice.

Beta-catenin, a protein component of adherens junctions, plays a role in the signalling pathway for cell proliferation. In this study, we examined the cellular distribution of beta-catenin in developing auditory epithelia of mice. Immunohistochemistry for Ki67 and cyclin D indicated active cell proliferation in premature auditory epithelia. In this period, the nuclear localization of beta-catenin in epithelial cells was observed together with expression of the lymphoid enhancer factor, a transcription factor in beta-catenin signalling. Epithelial cells showing nuclear localization of beta-catenin disappeared at the same time, as there was a decrease of cell proliferation. These findings indicate that nuclear translocation of beta-catenin plays a role in cell proliferation in developing auditory epithelia.

Disruption and restoration of cell-cell junctions in mouse vestibular epithelia following aminoglycoside treatment.

The intracellular junction complexes, which consist of tight junctions (TJ), adherens junctions (AJ), and desmosomes, mediate cell-cell adhesion in epithelial cells. E-cadherin, which is a major component of AJ, plays a role not only in the maintenance of cell-cell junctions, but also in repressing cell proliferation. In this study, we examined changes of E-cadherin expression in mouse vestibular epithelia following local application of neomycin using immunohistochemistry and western blotting, and morphology of cell-cell junctions by transmission electron microscopy (TEM). Immunohistochemistry and western blotting revealed down-expression of E-cadherin and its consecutive recovery. TEM demonstrated temporal disruption of cell-cell junctions. Morphology of cell-cell junctions was more rapidly restored than recovery of E-cadherin expression. Transient disruption of cell-cell junctions and down-expression of E-cadherin is a rational response for the deletion of dying hair cells, and may be associated with a limited capacity for cell proliferations in mammalian vestibular epithelia following their rapid restoration.

Novel strategy for treatment of inner ears using a biodegradable gel.

OBJECTIVE: The present study aimed to evaluate the efficacy of a biodegradable hydrogel as a drug-delivery medium for the inner ear. Brain-derived neurotrophic factor (BDNF) was chosen as the agent to be administered. METHOD: First, we used an enzyme-linked immunosorbent assay to measure BDNF concentrations in the cochlear fluid after placing a hydrogel containing this agent onto the round-window membrane of the ear. Second, the functional and histologic protection of the auditory primary neurons (spiral ganglion neurons [SGNs]) by BDNF applied through the hydrogel was examined using an animal model of SGN degeneration. RESULTS: The results revealed sustained delivery of BDNF into the cochlear fluid by way of the hydrogel. Second, the functional and histologic protection of the auditory primary neurons (SGNs) by BDNF applied through the hydrogel was examined using an animal model of SGN degeneration. The measurement of electrically evoked auditory-brainstem responses demonstrated that BDNF delivered by way of the hydrogel significantly reduced the threshold elevation. Immunohistochemistry for neurofilament 200 kD demonstrated increased survival of SGNs because of BDNF application through the hydrogel. CONCLUSION: These findings indicate that biodegradable hydrogels can be used for drug delivery to the inner ear.

Destiny of autologous bone marrow-derived stromal cells implanted in the vocal fold.

OBJECTIVES: The aim of this study was to investigate the destiny of implanted autologous bone marrow-derived stromal cells (BSCs) containing mesenchymal stem cells. We previously reported the successful regeneration of an injured vocal fold through implantation of BSCs in a canine model. However, the fate of the implanted BSCs was not examined. In this study, implanted BSCs were traced in order to determine the type of tissues resulting at the injected site of the vocal fold. METHODS: After harvest of bone marrow from the femurs of green fluorescent transgenic mice, adherent cells were cultured and selectively amplified. By means of a fluorescence-activated cell sorter, it was confirmed that some cells were strongly positive for mesenchymal stem cell markers, including CD29, CD44, CD49e, and Sca-1. These cells were then injected into the injured vocal fold of a nude rat. Immunohistologic examination of the resected vocal folds was performed 8 weeks after treatment. RESULTS: The implanted cells were alive in the host tissues and showed positive expression for keratin and desmin, markers for epithelial tissue and muscle, respectively. The implanted BSCs differentiated into more than one tissue type in vivo. CONCLUSIONS: Cell-based tissue engineering using BSCs may improve the quality of the healing process in vocal fold injuries.

Neck and superior mediastinal granular cell tumor excised via a combined approach.

Granular cell tumor (GCT) is an uncommon tumor of Schwann cell origin. GCT occurs in various sites throughout the body, but mediastinal GCT is very rare. We present an extremely rare case of GCT of the neck and superior mediastinum. A 36-year-old man with a 3-month history of cough was investigated at our hospital. CT and MRI revealed a spindle-shaped mass in the left neck and superior mediastinum, with features suggesting a neurogenic tumor. The tumor was successfully excised via combined neck incision and video-assisted thoracoscopic surgery. Histopathological examination showed proliferation of polygonal and spindled cells with eosinophilic granule-rich cytoplasm. These cells were S-100 protein positive, and the cytoplasmic granules were periodic acid-Schiff positive. Based on these histopathological and immunohistochemical findings, a diagnosis of GCT was established. The patient developed hoarseness immediately after the operation, and laryngoscopy revealed the left vocal cord palsy in the paramedian position, which resolved after about 3 months. The tumor did not recur during the following 10 months.

Trophic support of mouse inner ear by neural stem cell transplantation.

In the auditory system, efforts to reduce degeneration of spiral ganglion neurons have the immediate objective of improving clinical benefits of cochlear implants, which are small devices designed to stimulate spiral ganglion neurons electronically. Recent studies have indicated several neurotrophins can enhance survival of spiral ganglion neurons. However, the strategy for application of neurotrophins in inner ear is still a matter of debate. In this study, we examined the potential of cell therapy as a strategy for application of neurotrophins in the inner ear. Neural stem cells obtained from green fluorescent protein-transgenic mice were used as donor cells. Medium containing neural stem cells was injected into mouse inner ear. Histological analysis 4 weeks later revealed that transplant-derived cells survived in inner ear and that most transplant-derived cells in the cochlea had differentiated into glial cells. Moreover, expression of glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor was observed in transplant-derived cells. These findings indicate that transplantation of neural stem cells can be a useful strategy for application of neurotrophins in inner ear.

Role of the F-box protein Skp2 in cell proliferation in the developing auditory system in mice.

The F-box protein, Skp2 positively regulates the G1-S transition by controlling the stability of several G1 regulators, including p27. To evaluate the role of Skp2 in the mammalian developing auditory systems, the expression of Skp2 was examined together with the expression of p27 in auditory systems. Our data show expression of Skp2 in auditory epithelia and neurons at an early stage of development. During differentiation processes, the onset of p27 expression was observed together with the down-regulation of Skp2 expression, in auditory epithelia. In contrast, an alteration of expression of p27 and Skp2 in the greater epithelial ridge and spiral ganglion appeared after differentiation of hair cells. These findings suggest that Skp2 plays a crucial role in development of mammalian auditory systems.

Fate of neural stem cells grafted into injured inner ears of mice.

Loss of sensory hair cells in the inner ear is a major cause of permanent hearing loss, since regeneration of hair cells rarely occurs in mammals. The aim of this study was to examine the potential of neural stem cell transplantation to restore inner ear hair cells in mice. Fetal neural stem cells were transplanted into the mouse inner ear after drug-induced injury. Histological analysis demonstrates that the majority of grafted cells differentiated into glial or neural cells in the inner ear. Strikingly, however, we show that grafted cells integrate in vestibular sensory epithelia and express specific markers for hair cells. This finding suggests that transplanted neural stem cells have the potential to differentiate and restore inner ear hair cells.

Transplantation of bone marrow stromal cells into the cochlea of chinchillas.

This study aimed to evaluate the potential of bone marrow stromal cells for treatment of inner ear diseases. Autologous marrow cells labeled with Dil were implanted into the inner ear of five gentamicin-treated chinchillas. Histological analysis 3 weeks later revealed robust survival of grafted marrow cells in multiple regions within the cochlea. Marrow cells implanted in the basal turn of the cochlea migrated as far as the apical end or into the spiral ligament of the cochlea. Some grafted cells expressed a neuronal or glial cell marker, indicating their ability to differentiate into neuronal or glial cells. Survival, migrational mobility and differentiation of autologous marrow cells in damaged cochlea suggest their potential as transplants for treatment of various degenerative inner ear diseases.

Alteration of E-cadherin and beta-catenin in mouse vestibular epithelia during induction of apoptosis.

The aim of this study was to examine if adhesion molecules had relation with degeneration and regeneration processes of mammalian vestibular epithelia. The distribution of E-cadherin and beta-catenin was immunohistochemically examined in normal and aminoglycoside-treated utricles of mice. E-cadherin and beta-catenin linearly expressed between epithelial cells in normal specimens. Aminoglycoside injury resulted in temporal alteration in distribution of these molecules with induction of apoptosis in hair cells. Degradation of both molecules was widely observed in vestibular epithelia, while some supporting cells exhibited accumulation of beta-catenin. After completion of induction of apoptosis, expression of these adhesion molecules was normal in distribution. These findings suggest that the E-cadherin-beta-catenin complex plays roles in degeneration and subsequent repair processes in vestibular epithelia affected by aminoglycosides.

Alteration in expression of p27 in auditory epithelia and neurons of mice during degeneration.

The aim of this study was to examine roles of p27, a cyclin-dependent kinase inhibitor, in cochleae of adult mice. Expression of p27 was found in cochlear supporting cells and spiral ganglion neurons of normal mice. Cisplatin treatment caused progressive degeneration of cochlear supporting cells and spiral ganglion neurons, and numbers of p27-positive cells in these cells decreased. This indicates a close relationship between p27 and cell death in cochleae. However, the relationships between decrease in number of p27-positive cells and that of survival cells differed according to type of cell. For Deiters' cells, there was apparent decrease in number of p27-positive cells, although no decrease in cell numbers. The present findings indicate that p27 plays roles in degeneration of cochleae according to cell type.

A novel technique for inducing local inner ear damage.

With significant development of mouse genomics and the availability of transgenic and knockout mice, the mouse will be the preferred animal model for inner ear research. However, few studies have used mice as experimental animals for examination of hair cell degeneration, because of their relative resistance to ototoxic agents and difficulties in surgical treatment. This study presents a model for induction of apoptotic cell death in sensory epithelia of the mouse inner ear using injection of neomycin into the posterior semicircular canal. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay revealed that local application of neomycin produced sufficient induction of apoptotic cell death in both auditory and vestibular epithelia over a definite time course. Supplementation of the general caspase-inhibitor significantly reduced induction of TUNEL-positive cells, indicating caspase-dependency of apoptotic cell death observed in the present model. In addition, the approach to the posterior semicircular canal was an easy technique, and sham-operation induced no significant induction of TUNEL-positive cells. This model, hence, enables the use of various genetic tools in studies for mechanisms of hair cell apoptosis.

A novel model for rapid induction of apoptosis in spiral ganglions of mice.

OBJECTIVES/HYPOTHESIS: The survival of the spiral ganglion (SG) is a critical issue in preservation of hearing. Research on topics related to this issue requires a mouse experimental model because such a model has advantages including use of genetic information and knockout or "knockin" mice. Thus, the aim of the study was to establish a mouse model for induction of apoptosis of SG neurons with a definite time course. STUDY DESIGN: Laboratory study using experimental animals. METHODS: C57BL/6 mice were used as experimental animals and were subjected to direct application of cisplatin into the inner ear. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay and immunostaining for Neurofilament 200-kD (NF) and peripherin were used for analysis of SG degeneration. In addition, generation of peroxynitrite in affected spiral ganglions was examined by immunostaining for nitrotyrosine. Cellular location of activated caspase-9 and cytochrome-c in dying SG neurons were examined for analysis of cell death pathway. RESULTS: The TUNEL assay and immunohistochemical analysis for NF and peripherin indicated that type I neurons in spiral ganglions were deleted through the apoptotic pathway over time. Spiral ganglion neurons treated with cisplatin exhibited expression of nitrotyrosine, indicating induction of peroxynitrite by cisplatin. In dying SG neurons, expression of activated caspase-9 and translocation of cytochrome-c from mitochondria to cytoplasm were observed, indicating the mitochondrial pathway of apoptosis. CONCLUSION: The predictable fashion of induction of apoptosis in SG neurons over a well-defined time course in the model in the study will aid studies of the molecular mechanism of cell death and elucidation of a strategy for prevention of SG degeneration.

Role of reactive radicals in degeneration of the auditory system of mice following cisplatin treatment.

OBJECTIVE: It has been suggested that reactive radical species are involved in the mechanism of cisplatin-induced hearing loss. However, the nature of the free radicals involved is not fully understood. We examined the effects of two highly reactive species, hydroxyl radicals and peroxynitrite, on the auditory system of mice following cisplatin treatment. MATERIAL AND METHODS: Expression of 4-hydroxynonenal (HNE), a marker of lipid peroxidation by the hydroxyl radical, and nitrotyrosine (NT), a marker for protein peroxidation by peroxynitrite, was examined immunohistochemically in mouse cochleae injured by means of local application of cisplatin. RESULTS: Loss of outer hair cells (OHCs) and spiral ganglia was found in cochleae affected by cisplatin. Both HNE and NT were detected in auditory epithelia and neurons damaged by cisplatin. Interestingly, auditory hair cells produced HNE, but not NT. Our findings indicate contributions by both HNE and NT to the degeneration of the auditory system due to cisplatin, and a crucial role of the hydroxyl radical in degeneration of OHCs. CONCLUSION: The hydroxyl radical may be a critical target for a strategy aimed at protecting auditory function from cisplatin toxicity.