Heterozygous mutation of Ush1g/Sans in mice causes early-onset progressive hearing loss, which is recovered by reconstituting the strain-specific mutation in Cdh23.

Most clinical reports have suggested that patients with congenital profound hearing loss have recessive mutations in deafness genes, whereas dominant alleles are associated with progressive hearing loss (PHL). Jackson shaker (Ush1gjs) is a mouse model of recessive deafness that exhibits congenital profound deafness caused by the homozygous mutation of Ush1g/Sans on chromosome 11. We found that C57BL/6J-Ush1gjs/+ heterozygous mice exhibited early-onset PHL (ePHL) accompanied by progressive degeneration of stereocilia in the cochlear outer hair cells. Interestingly, ePHL did not develop in mutant mice with the C3H/HeN background, thus suggesting that other genetic factors are required for ePHL development. Therefore, we performed classical genetic analyses and found that the occurrence of ePHL in Ush1gjs/+ mice was associated with an interval in chromosome 10 that contains the cadherin 23 gene (Cdh23), which is also responsible for human deafness. To confirm this mutation effect, we generated C57BL/6J-Ush1gjs/+, Cdh23c.753A/G double-heterozygous mice by using the CRISPR/Cas9-mediated Cdh23c.753A>G knock-in method. The Cdh23c.753A/G mice harbored a one-base substitution (A for G), and the homozygous A allele caused moderate hearing loss with aging. Analyses revealed the complete recovery of ePHL and stereocilia degeneration in C57BL/6J-Ush1gjs/+ mice. These results clearly show that the development of ePHL requires at least two mutant alleles of the Ush1g and Cdh23 genes. Our results also suggest that because the SANS and CDH23 proteins form a complex in the stereocilia, the interaction between these proteins may play key roles in the maintenance of stereocilia and the prevention of ePHL.

Generating mouse models of degenerative diseases using Cre/lox-mediated in vivo mosaic cell ablation.

Most degenerative diseases begin with a gradual loss of specific cell types before reaching a threshold for symptomatic onset. However, the endogenous regenerative capacities of different tissues are difficult to study, because of the limitations of models for early stages of cell loss. Therefore, we generated a transgenic mouse line (Mos-iCsp3) in which a lox-mismatched Cre/lox cassette can be activated to produce a drug-regulated dimerizable caspase-3. Tissue-restricted Cre expression yielded stochastic Casp3 expression, randomly ablating a subset of specific cell types in a defined domain. The limited and mosaic cell loss led to distinct responses in 3 different tissues targeted using respective Cre mice: reversible, impaired glucose tolerance with normoglycemia in pancreatic ß cells; wound healing and irreversible hair loss in the skin; and permanent moderate deafness due to the loss of auditory hair cells in the inner ear. These mice will be important for assessing the repair capacities of tissues and the potential effectiveness of new regenerative therapies.

A 24-month-follow-up study of argon plasma coagulation of the inferior turbinate in patients with perennial nasal allergy.

We report a 24-month-follow-up study of argon plasma coagulation of the inferior turbinate (APC) in patients with perennial nasal allergy. This was a retrospective study, in which 41 patients with perennial allergic rhinitis were treated by inferior turbinate reduction using APC. The grades of nasal stuffiness, rhinorrhea, sneezing and the daily activity impairment caused by these nasal symptoms were evaluated before and then 6, 9, 12, 15, 18, 21, and 24 months after APC, using a questionnaire graded on a four-point scale according to the Severity Criteria of Symptoms of Nasal Allergy issued by the Japanese Society of Allergology. Both nasal stuffiness and any daily activity impairment significantly improved 6 months after APC. Twenty four months after APC, 8/10 (80%) of the patients reported mild or no stuffiness and 9/10 (90%) of the patients reported mild or no daily activity impairement. Neither rhinorrhea nor sneezing were significantly improved during this study. Of the 41 patients 18 (43.9%) received no additional treatment. A second APC treatment was administered to 10/41 (24.4%) patients during follow-up period. Additional conservative medications were needed in 15/41 (36.6%) patients. Among the patients uncontrolled by conservative medical treatment, inferior turbinate reduction using APC provides significant relief in a 24-month-follow-up from nasal stuffiness and daily activity impairment.

Phenotypic and expression analysis of a novel spontaneous myosin VI null mutant mouse.

In humans, hearing is a major factor in quality of life. Mouse models are important tools for the discovery of genes responsible for genetic hearing loss, often enabling analysis of the processes that regulate the onset of deafness in humans. Thus far, at least 400 deafness mutants have been discovered in laboratory mouse populations and used in the study of deafness. Here we report the discovery of a new spontaneous recessive Rinshoken shaker/waltzer (rsv) mutant derived from our in-house C57BL/6J stock, which exhibits circling and/or head-tossing behaviour and complete lack of auditory brain response to any sound pressure. The hearing and balance phenotypes are associated with structural defects, in particular, disorganisation and fusion of stereocilia in the inner ear hair cells. Two sets of intersubspecific N(2) mice were generated for the positional cloning of the rsv mutation. The mutant locus was mapped to a 4.8-Mb region of chromosome 9, which contains myosin VI (Myo6), a gene responsible for deafness in humans and Snell's waltzer mutation in mice. The rsv mutant showed reduced expressions of Myo6 mRNA and MYO6 protein in the inner ear. Moreover, no immunoreactivity was observed in the cochlear and vestibular hair cells in the rsv mutant mice. We sequenced the genomic region (30,154 bp) of Myo6, including all coding exons, a non-coding exon, UTRs and the Myo6 promoter; however, no mutation was discovered in these regions. We therefore speculate that loss of MYO6 expression might cause shaker/waltzer behaviour and deafness in the rsv mutant; also, loss of MYO6 expression might be the result of mutations in an unidentified regulatory region(s) of the gene.

A Case of Descending Necrotizing MediastinitisPenetrating to the Esophagus.

Here, we present the case of a 78-year-old man with a deep neck infection that caused descending necrotizing mediastinitis that extended from the pharynx to the stomach and was accompanied by two large esophageal fistulas and multiple gastric ulcers. We believe that the series of lesions were the signs of a hidden carcinoma.

Vlgr1 is required for proper stereocilia maturation of cochlear hair cells.

Very large G-protein coupled receptor (Vlgr1b) is the largest known G-protein coupled receptor. Its function is unknown, although mice with deletion of Vlgr1 (Vlgr1b together with other splicing variants, Vlgr1c, Vlgr1d and Vlgr1e) are known to exhibit audiogenic seizure susceptibility and VLGR1 is reported to be the gene responsible for Usher type 2C syndrome. We demonstrated here that Vlgr1-mutated mice suffered from a hearing defect because of inner ear dysfunction, as indicated by auditory brainstem response (ABR) and distortion product oto-acoustic emissions (DPOAE). The expression of Vlgr1 was identified in the developing hair cells perinatally, and the translated products were seen to be localized in the base of stereocilia on hair cells using confocal microscopy. This Vlgr1 localization was limited to the base of stereocilia within approximately 200-400 nm from the apical surface of hair cells, as shown by immunoelectron microscopy. The Vlgr1-mutated mice exhibited malformation of the stereocilia; the cochlear hair bundles were apparently normal at birth but then became disarranged at postnatal day 8. Furthermore, the stereocilia in the mutant mice became slanted and disarranged thereafter. These results indicate that loss of Vlgr1 resulted in abnormal development of stereocilia formation.

Short-term effect of argon plasma coagulation of the inferior turbinate in patients with perennial nasal allergy.

The aim of this study was to clarify the short-term effects of argon plasma coagulation (APC) of the inferior turbinate in patients with perennial nasal allergy. In a retrospective study, 32 patients with perennial allergic rhinitis were treated by inferior turbinate reduction using APC. Grades of nasal stuffiness, rhinorrhea, sneezing, nasal airflow resistance (NAR) and overall seriousness were evaluated before and then 1-4 and 8 weeks after APC. Subjective symptoms were assessed using a questionnaire in which nasal stuffiness, rhinorrhea and sneezing were graded on a four-point scale (severe, moderate, mild and none) using the Severity Criteria of Symptoms of Nasal Allergy issued by the Japanese Society of Allergology. NAR was measured using active anterior rhinomanometry (AAR) at the 100 Pa point; this was deemed to be an objective measurement of nasal obstruction. The numbers of patients examined before and 1-4 and 8 weeks after APC were 32, 31, 25, 17, 18 and 14, respectively. Both nasal stuffiness and NAR were significantly improved 2 weeks after APC, overall seriousness was significantly improved after 3 weeks and rhinorrhea was improved after 4 weeks. Sneezing did not significantly improve during this study. There was no significant change in the grades of the examined parameters during the period between 4 and 8 weeks after APC. The beneficial effects of APC begin to appear within 2 weeks after APC and no further improvement after about 4 weeks.

[Investigation of automated infant auditory screening using the Natus-ALGO Portable device].

The aim of this study was to compare the Natus-ALGO Portable (Portable) device with the Natus-ALGO 2e and to evaluate its usefulness. Portable, an automated ABR screener (Natus Medical, Foster City, CA, USA) was used to screen 826 neonates in our hospital between February 2002 and March 2003. The referral rate for the first automated ABR screening was 0.85% while that for the second was 0.48%. Hearing impairment was detected in 0.24% of all newborns. The mean duration of the automated ABR test was 2 minutes, 45 seconds. The referral rate and mean test duration of the Portable device was equivalent to that of the Natus-ALGO 2e. We concluded that the Portable device is a useful tool in view of its low cost and portability. Among those who passed the Portable screening, the number of sweeps in the neonatal intensive care unit was significantly greater than that in the maternity ward. Careful estimation of REFER in neonatal intensive care units is important because the incidence of positive fails in the neonatal intensive care unit was much higher than that in the maternity ward. The number of sweeps performed in neonates between the ages of 2 to 6 days was not significantly different.

[Peritonsillar abscess associated with infectious mononucleosis: retrospective study of three cases].

Three cases with infectious mononuculeosis associated with peritonsillar abscess were reviewed. The initial diagnoses in these three cases were tonsillitis or peritonsillitis. However, infectious mononucleosis was suspected because of an elevation in aminotransferases and was later confirmed by elevations in the titers of antibodies for Epstein-Barr virus. Peritonsillar abscesses developed and surgical drainage was performed in all three cases. The present study suggests a higher incidence of peritonsillar abscess in patients with infectious mononucleosis than previously expected.

Comparison of acute low-tone sensorineural hearing loss versus Meniere's disease by electrocochleography.

To clarify the pathogenesis of acute low-tone sensorineural hearing loss (ALHL), we retrospectively compared the electrocochleographic findings from 20 patients with ALHL with those from 58 patients with Meniere's disease (MD) classified into 4 groups (MD1 through MD4) according to their pure tone average. The mean summating potential-action potential ratio in the ALHL group was 0.35 +/- 0.13, which was significantly higher than the control ratio but similar to the ratio seen in the MD1 group (pure tone average < 25 dB hearing level). The mean detection threshold of the cochlear microphonics in the ALHL group was 32.0 +/- 9.4 dB normal hearing level, which was again similar to that seen in the MDI group. Moreover, more than 50% of patients with ALHL had normal cochlear microphonics input-output curves. We therefore conclude that the pathogenesis of ALHL arises from an endolymphatic hydrops with little or no impairment of hair cells that resembles early-stage MD.

Six1 controls patterning of the mouse otic vesicle.

Six1 is a member of the Six family homeobox genes, which function as components of the Pax-Six-Eya-Dach gene network to control organ development. Six1 is expressed in otic vesicles, nasal epithelia, branchial arches/pouches, nephrogenic cords, somites and a limited set of ganglia. In this study, we established Six1-deficient mice and found that development of the inner ear, nose, thymus, kidney and skeletal muscle was severely affected. Six1-deficient embryos were devoid of inner ear structures, including cochlea and vestibule, while their endolymphatic sac was enlarged. The inner ear anomaly began at around E10.5 and Six1 was expressed in the ventral region of the otic vesicle in the wild-type embryos at this stage. In the otic vesicle of Six1-deficient embryos, expressions of Otx1, Otx2, Lfng and Fgf3, which were expressed ventrally in the wild-type otic vesicles, were abolished, while the expression domains of Dlx5, Hmx3, Dach1 and Dach2, which were expressed dorsally in the wild-type otic vesicles, expanded ventrally. Our results indicate that Six1 functions as a key regulator of otic vesicle patterning at early embryogenesis and controls the expression domains of downstream otic genes responsible for respective inner ear structures. In addition, cell proliferation was reduced and apoptotic cell death was enhanced in the ventral region of the otic vesicle, suggesting the involvement of Six1 in cell proliferation and survival. In spite of the similarity of otic phenotypes of Six1- and Shh-deficient mice, expressions of Six1 and Shh were mutually independent.

[Bone-anchored hearing aid (BAHA): report of 2 cases].

In this first case report in Japan, we described 2 patients treated using a bone conductive hearing aid with skin-penetrating implant, or bone-anchored hearing aid (BAHA). Both suffered from chronic otitis media and had received bilateral canal down tympanomastoidectomy. Case 1 was a 61-year-old woman with a conventional air conductive hearing aid in her right ear. There was no aural discharge in either ear. A pure-tone average showed 82.5 dBHL (air), 44.3 dBHL (bone) in the right ear and 93.8 dBHL (air), 48.8 dBHL (bone) in the left ear. Case 2 was a 38-year-old woman with a conventional hearing aid in her left ear, from which there was persistent aural discharge. A pure-tone average showed 48.8 dBHL(air), 15.0 dBHL (bone) in the right ear, and 60.0 dBHL(air), 20.0 dBHL(bone) in the left ear. Both underwent BAHA implant in the right ear without adverse reaction during 9 months of postoperative follow-up after surgery. No difference was seen in the aided hearing level or speech discrimination score between BAHA and air conduction hearing aids but both patients preferred to BAHA because of its greater comfort and audibility.

Mutations in a new scaffold protein Sans cause deafness in Jackson shaker mice.

The Jackson shaker (js) mouse carries a recessive mutation causing phenotypes such as deafness, abnormal behavior (circling and/or head-tossing) and degeneration of inner ear neuroepithelia. Two alleles have been identified so far, the original js and js(seal). A contig of three BAC clones was isolated by positional cloning. Two of the clones rescue the js phenotype by BAC transgenesis. Analysis of transcripts in an overlapping region of the two clones revealed a gene encoding a new scaffold-like protein, Sans, that showed mutations in the two js mutants. One was a guanine nucleotide insertion in the original js allele and the other a 7-base insertion in the js(seal) allele. Both insertions are predicted to inactivate the Sans protein by frameshift mutations resulting in a truncated protein lacking the C-terminal SAM domain. Cochlear hair cells in the js mutants show disorganized stereocilia bundles, and Sans were highly expressed in inner and outer hair cells of cochlea. The existence of major motifs, ankyrin repeats and a SAM domain suggests that Sans may have an important role in the development and maintenance of the stereocilia bundles through protein-protein interaction.