Quantitative analysis and correlative evaluation of video-oculography, micro-computed tomography, and histopathology in Pendrin-null mice.

Patients with SLC26A4 mutations exhibit highly variable hearing loss and vestibular dysfunction. Although Slc26a4 mutant mice similarly exhibit vestibular deficits, including circling behavior, head tilting, and torticollis, the underlying pathogenesis of the vestibular symptoms remains unclear, hindering its effective management for patients with SLC26A4 mutations. In this study, we evaluated the equilibrium function using the inspection equipment, which can record eye movements against rotational, gravitational, and thermal stimulations. Moreover, we correlated the degree of functional impairment with the morphological alterations observed in Slc26a4Δ/Δ mice. The rotational stimulus and ice water caloric tests revealed considerable impairment of the semicircular canal, while the tilted gravitational stimulus test showed a severe functional decline of the otolithic system in Slc26a4Δ/Δ mice. Generally, the degree of impairment was more severe in circling Slc26a4Δ/Δ mice than in non-circling Slc26a4Δ/Δ mice. In non-circling Slc26a4Δ/Δ mice, the semicircular canal function was normal. Micro-computed tomography results showed enlargement of the vestibular aqueduct and bony semicircular canals but no correlative relationship between the severity of the caloric response and the size of bony labyrinths. Giant otoconia and a significant decrease in total otolith volume in the saccule and utricle were observed in Slc26a4Δ/Δ mice. However, the giant otoconia were not overly dislocated in the bony otolithic system and ectopic otoconia were absent in the semicircular canal. The number and morphology of the utricular hair cells in Slc26a4Δ/Δ mice were not significantly reduced compared to those in Slc26a4Δ/+ mice. Collectively, we can conclude that vestibular impairments are mainly associated with otoconia formation and morphology rather than hair cell degeneration. In addition, severe disturbances of semicircular canals cause circling behavior in Slc26a4Δ/Δ mice. Our comprehensive morphological and functional assessments apply to mouse models of other genetic diseases with vestibular impairment.

Prediction of postoperative visual acuity after vitrectomy for macular hole using deep learning-based artificial intelligence.

PURPOSE: To create a model for prediction of postoperative visual acuity (VA) after vitrectomy for macular hole (MH) treatment using preoperative optical coherence tomography (OCT) images, using deep learning (DL)-based artificial intelligence. METHODS: This was a retrospective single-center study. We evaluated 259 eyes that underwent vitrectomy for MHs. We divided the eyes into four groups, based on their 6-month postoperative Snellen VA values: (A) ≥ 20/20; (B) 20/25-20/32; (C) 20/32-20/63; and (D) ≤ 20/100. Training data were randomly selected, comprising 20 eyes in each group. Test data were also randomly selected, comprising 52 total eyes in the same proportions as those of each group in the total database. Preoperative OCT images with corresponding postoperative VA values were used to train the original DL network. The final prediction of postoperative VA was subjected to regression analysis based on inferences made with DL network output. We created a model for predicting postoperative VA from preoperative VA, MH size, and age using multivariate linear regression. Precision values were determined, and correlation coefficients between predicted and actual postoperative VA values were calculated in two models. RESULTS: The DL and multivariate models had precision values of 46% and 40%, respectively. The predicted postoperative VA values on the basis of DL and on preoperative VA and MH size were correlated with actual postoperative VA at 6 months postoperatively (P < .0001 and P < .0001, r = .62 and r = .55, respectively). CONCLUSION: Postoperative VA after MH treatment could be predicted via DL using preoperative OCT images with greater accuracy than multivariate linear regression using preoperative VA, MH size, and age.

Cyclotron production of 225Ac from an electroplated 226Ra target.

PURPOSE: We demonstrate cyclotron production of high-quality 225Ac using an electroplated 226Ra target. METHODS: 226Ra was extracted from legacy Ra sources using a chelating resin. Subsequent ion-exchange purification gave pure 226Ra with a certain amount of carrier Ba. The radium target was prepared by electroplating. We successfully deposited about 37 MBq of 226Ra on a target box. Maximum activation was achieved using 15.6 MeV protons on the target at 20 µA for 5 h. Two functional resins with various concentrations of nitric acid purified 225Ac and recovered 226Ra. Cooling the intermediate 225Ac for 2-3 weeks decayed the major byproduct of 226Ac and increased the radionuclidic purity of 225Ac. Repeating the same separation protocol provided high-quality 225Ac. RESULTS: We obtained 225Ac at a yield of about 2.4 MBq at the end of bombardment (EOB), and the subsequent initial purification gave 1.7 MBq of 225Ac with 226Ac/225Ac ratio of < 3% at 4 days from EOB. Additional cooling time coupled with the separation procedure (secondary purification) effectively increased the 225Ac (4n + 1 series) radionuclidic purity up to 99 + %. The recovered 225Ac had a similar identification to commercially available 225Ac originating from a 229Th/225Ac generator. CONCLUSION: This procedure, which involves the 226Ra(p,2n)225Ac reaction and the appropriate purification, has the potential to be a major alternative pathway for 225Ac production because it can be performed in any facility with a compact cyclotron to address the increasing demand for 225Ac.

[Factors associated with behaviors to prevent COVID-19 infection during the declaration of emergency: A study among Tokyo residents].

Objectives　The COVID-19 pandemic spread rapidly across the globe during the first half of 2020. In Japan, a state of emergency was declared on April 7, 2020, which had a significant impact on the life of citizens. This study focused on behaviors like avoiding going out or coming in contact with others and frequent hand-washing to prevent the infection and the spread of COVID-19 among people living in Tokyo. We also examined the factors associated with these behaviors during the declaration of emergency.Methods　An online survey was conducted from April 26 to 29, 2020, approximately 20 days after the declaration of the emergency, among men and women aged 20-69 years living in Tokyo. The study framework was based on the protection motivation theory, which explains the risk-reducing behaviors, and focus theory of normative conduct, which explains the effect of others' behavior on one's own behavior. The frequency of behaviors like avoiding going out or coming in contact with others and frequent hand-washing, as well as the perception of the risk of COVID-19 during the week preceding the survey, were assessed. Each preventive action was evaluated based on the following factors: perceived effectiveness (response efficacy), perceived practicability (self-efficacy), necessary cost (response cost), and perceptions of how much should be done (injunctive norm) and how well others are doing it (descriptive norm). Hierarchical multiple regression analysis with these behaviors as outcomes were performed.Results　This study included 1,034 participants (50.3% male, mean age 44.82 years, standard deviation 14.00 years). The analyses of the frequency of avoiding going out or coming in contact with others showed that the injunctive norm was positively associated with the behavior (standardized partial regression coefficient (ß)=0.343, P<0.001), while the descriptive norm was negatively associated with the behavior (ß=-0.074, P=0.010). Furthermore, the two-way interaction between risk perception, response efficacy, and self-efficacy was significant (ß=0.129, P<0.001), indicating that risk perception was positively associated with the behavior only when either response efficacy or self-efficacy was low. A similar analysis conducted for hand-washing behavior revealed that injunctive norm (ß=0.256, P<0.001) and response efficacy (ß=0.132, P<0.001) were positively associated with the behavior, while the response cost (ß=-0.193, P<0.001) was negatively associated with the behavior.Conclusion　Some variables in the protection motivation theory and the focus theory of normative conduct were related to the behavior for the prevention of COVID-19. The results suggest that the application of these theories is useful in future studies.

Predicting anxiety state using smartphone-based passive sensing.

This study predicts the change of stress levels using real-world and online behavioral features extracted from smartphone log information. Previous studies of stress detection using smartphone data focused on a single feature and did not consider all features simultaneously. We propose a method to extract a co-occurring combination of a user's real-world and online behavioral features by converting raw sensor data into categorical features. We conducted an experiment in which the State Trait Anxiety Inventory (STAI) was used to assess the anxiety-related stress levels of 20 healthy participants. The participants installed a log-collecting application on their smartphones and answered the STAI questions once a day for one month. The proposed method showed an F-score of 74.2%, which is 4.0% higher than the F-score of previous studies (70.2%) that used single non-combined features. The results demonstrate that anxiety-related stress levels can be predicted using combined features extracted from smartphone log data.

Mutations in TBC1D24, a gene associated with epilepsy, also cause nonsyndromic deafness DFNB86.

Inherited deafness is clinically and genetically heterogeneous. We recently mapped DFNB86, a locus associated with nonsyndromic deafness, to chromosome 16p. In this study, whole-exome sequencing was performed with genomic DNA from affected individuals from three large consanguineous families in which markers linked to DFNB86 segregate with profound deafness. Analyses of these data revealed homozygous mutation c.208G>T (p.Asp70Tyr) or c.878G>C (p.Arg293Pro) in TBC1D24 as the underlying cause of deafness in the three families. Sanger sequence analysis of TBC1D24 in an additional large family in which deafness segregates with DFNB86 identified the c.208G>T (p.Asp70Tyr) substitution. These mutations affect TBC1D24 amino acid residues that are conserved in orthologs ranging from fruit fly to human. Neither variant was observed in databases of single-nucleotide variants or in 634 chromosomes from ethnically matched control subjects. TBC1D24 in the mouse inner ear was immunolocalized predominantly to spiral ganglion neurons, indicating that DFNB86 deafness might be an auditory neuropathy spectrum disorder. Previously, six recessive mutations in TBC1D24 were reported to cause seizures (hearing loss was not reported) ranging in severity from epilepsy with otherwise normal development to epileptic encephalopathy resulting in childhood death. Two of our four families in which deafness segregates with mutant alleles of TBC1D24 were available for neurological examination. Cosegregation of epilepsy and deafness was not observed in these two families. Although the causal relationship between genotype and phenotype is not presently understood, our findings, combined with published data, indicate that recessive alleles of TBC1D24 can cause either epilepsy or nonsyndromic deafness.

SLC26A4 targeted to the endolymphatic sac rescues hearing and balance in Slc26a4 mutant mice.

Mutations of SLC26A4 are a common cause of human hearing loss associated with enlargement of the vestibular aqueduct. SLC26A4 encodes pendrin, an anion exchanger expressed in a variety of epithelial cells in the cochlea, the vestibular labyrinth and the endolymphatic sac. Slc26a4 (Δ/Δ) mice are devoid of pendrin and develop a severe enlargement of the membranous labyrinth, fail to acquire hearing and balance, and thereby provide a model for the human phenotype. Here, we generated a transgenic mouse line that expresses human SLC26A4 controlled by the promoter of ATP6V1B1. Crossing this transgene into the Slc26a4 (Δ/Δ) line restored protein expression of pendrin in the endolymphatic sac without inducing detectable expression in the cochlea or the vestibular sensory organs. The transgene prevented abnormal enlargement of the membranous labyrinth, restored a normal endocochlear potential, normal pH gradients between endolymph and perilymph in the cochlea, normal otoconia formation in the vestibular labyrinth and normal sensory functions of hearing and balance. Our study demonstrates that restoration of pendrin to the endolymphatic sac is sufficient to restore normal inner ear function. This finding in conjunction with our previous report that pendrin expression is required for embryonic development but not for the maintenance of hearing opens the prospect that a spatially and temporally limited therapy will restore normal hearing in human patients carrying a variety of mutations of SLC26A4.

[Otologic Manifestations in Patients with ANCA Associated Vasculitis-Comparative Analysis among Microscopic Polyangiitis, Granulomatosis with Polyangiitis and Eosinophilic Granulomatosis with Polyangiitis].

Anti-neutrophil cytoplasmic antibody (ANCA) -associated vasculitides (AAVs) include microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA) and eosinophilic granulomatosis with polyangiitis (EGPA), the incidences of which are reported to be increasing in Japan. We reviewed the clinical records of 20 cases with systemic AAVs (five cases with MPA, nine cases with GPA, and six cases with EGPA), who visited our otolaryngology department with otological symptoms from 2004 to 2014, and compared the otological characteristics among the diseases. Otologic symptoms appeared as an initial symptom(s) in 40% of MPA cases, 56% of GPA cases, and 83% of EGPA cases. GPA and EGPA cases showed a variety of symptoms such as otalgia, otorrhea, hearing loss, ear fullness, tinnitus and dizziness, while MPA cases showed only hearing loss and ear fullness, but otalgia or otorrhea. AAVs and otitis media associated with ANCA vasculitis (OMAAV) are usually diagnosed shortly after the appearance of otological symptoms in GPA cases, while the final diagnosis is delayed in EGPA cases. Furthermore, the diagnosis of OMAAV was made after the diagnosis of AAV in most cases of EGPA. More than half of MPA cases did not meet the diagnostic. criteria for OMAAV. It is noteworthy that in a significant number of AAV patients with ear disease, otological symptoms are supposed to appear as an initial symptom(s). Therefore, otolaryngologists have a major role to achieve early diagnosis of AAV. The patients with adult-onset inflammation of the middle ear, inner ear or both should undergo careful examinations, and they should be closely followed even if the diagnosis is uncertain.

Clinical Characteristics of Pediatric Deep Neck Abscesses.

Pediatric deep neck abscesses are a relatively rare and can lead to critical or life-threatening situations. However, the clinical characteristics of pediatric deep neck abscesses are not fully understood in Japan. We conducted a retrospective study of the clinical characteristics of children presenting with pediatric deep neck abscesses at our hospital. All pediatric patients were diagnosed with deep neck abscesses on the basis of the clinical findings and computed tomography (CT) scanning of the neck between April 2009 and March 2014. The incidence, initial examining department, sex, age, presenting signs and symptoms, physical findings, duration between onset and admission, timing of CT scanning, abscess location, causative organism, and method of treatment were determined from the medical records. 　We identified a total of 20 pediatric patients with deep neck abscesses, with a mean incidence of 4.0±1.9 cases per year. Pediatric deep neck abscesses were more common during winter and spring. Most patients initially presented to the pediatric department before consulting an otolaryngologist. Fourteen (70%) patients were male and six (30%) were female, with no obvious peak age of onset. The mean duration between onset and admission was 7.2±3.9 days. The mean timing of CT scanning was 8.1±3.6 days after onset. The most commonly involved area was the retropharyngeal space in nine (45%) and the retro-cervical space in eight (40%) patients. The most frequent causative organism was Staphylococcus aureus (20%), with no cases of antibiotic-resistant bacteria infection observed. Majority of the children were initially managed with conservative treatment. Five patients who failed to improve within 48 h of treatment subsequently underwent surgical drainage. No significant complications such as descending mediastinitis and septic shock were observed in any of the patients.

Slc26a4-insufficiency causes fluctuating hearing loss and stria vascularis dysfunction.

SLC26A4 mutations can cause a distinctive hearing loss phenotype with sudden drops and fluctuation in patients. Existing Slc26a4 mutant mouse lines have a profound loss of hearing and vestibular function, with severe inner ear malformations that do not model this human phenotype. In this study, we generated Slc26a4-insufficient mice by manipulation of doxycycline administration to a transgenic mouse line in which all Slc26a4 expression was under the control of doxycycline. Doxycycline was administered from conception to embryonic day 17.5, and then it was discontinued. Auditory brainstem response thresholds showed significant fluctuation of hearing loss from 1 through 3months of age. The endocochlear potential, which is required for inner ear sensory cell function, correlated with auditory brainstem response thresholds. We observed degeneration of stria vascularis intermediate cells, the cells that generate the endocochlear potential, but no other abnormalities within the cochlea. We conclude that fluctuations of hearing result from fluctuations of the endocochlear potential and stria vascularis dysfunction in Slc26a4-insufficient mouse ears. This model can now be used to test potential interventions to reduce or prevent sudden hearing loss or fluctuation in human patients. Our strategy to generate a hypomorphic mouse model utilizing the tet-on system will be applicable to other diseases in which a hypomorphic allele is needed to model the human phenotype.

A noncoding point mutation of Zeb1 causes multiple developmental malformations and obesity in Twirler mice.

Heterozygous Twirler (Tw) mice develop obesity and circling behavior associated with malformations of the inner ear, whereas homozygous Tw mice have cleft palate and die shortly after birth. Zeb1 is a zinc finger protein that contributes to mesenchymal cell fate by repression of genes whose expression defines epithelial cell identity. This developmental pathway is disrupted in inner ears of Tw/Tw mice. The purpose of our study was to comprehensively characterize the Twirler phenotype and to identify the causative mutation. The Tw/+ inner ear phenotype includes irregularities of the semicircular canals, abnormal utricular otoconia, a shortened cochlear duct, and hearing loss, whereas Tw/Tw ears are severely malformed with barely recognizable anatomy. Tw/+ mice have obesity associated with insulin-resistance and have lymphoid organ hypoplasia. We identified a noncoding nucleotide substitution, c.58+181G>A, in the first intron of the Tw allele of Zeb1 (Zeb1(Tw)). A knockin mouse model of c.58+181G>A recapitulated the Tw phenotype, whereas a wild-type knockin control did not, confirming the mutation as pathogenic. c.58+181G>A does not affect splicing but disrupts a predicted site for Myb protein binding, which we confirmed in vitro. In comparison, homozygosity for a targeted deletion of exon 1 of mouse Zeb1, Zeb1(ΔEx1), is associated with a subtle abnormality of the lateral semicircular canal that is different than those in Tw mice. Expression analyses of E13.5 Twirler and Zeb1(ΔEx1) ears confirm that Zeb1(ΔEx1) is a null allele, whereas Zeb1(Tw) RNA is expressed at increased levels in comparison to wild-type Zeb1. We conclude that a noncoding point mutation of Zeb1 acts via a gain-of-function to disrupt regulation of Zeb1(Tw) expression, epithelial-mesenchymal cell fate or interactions, and structural development of the inner ear in Twirler mice. This is a novel mechanism underlying disorders of hearing or balance.

The role of SLC26A4 in bony labyrinth development and otoconial mineralization in mouse models.

Inner ear malformations are predominantly attributed to developmental arrest during the embryonic stage of membranous labyrinth development. Due to the inherent difficulty in clinically assessing the status of the membranous labyrinth, these malformations are diagnosed with radiographic imaging, based on the morphological characteristics of the bony labyrinth. While extensive research has elucidated the intricacies of membranous labyrinth development in mouse models, comprehensive investigations into the developmental trajectory of the bony labyrinth, especially about its calcification process, have been notably lacking. One of the most prominent types of inner ear malformations is known as incomplete partition (IP), characterized by nearly normal external cochlear appearance but pronounced irregularities in the morphology of the modiolus and inter-scalar septa. IP type II (IP-II), also known as Mondini dysplasia, is generally accompanied by an enlargement of the vestibular aqueduct and is primarily attributed to mutations in the SLC26A4 gene. In the case of IP-II, the modiolus and inter-scalar septa of the cochlear apex are underdeveloped or missing, resulting in the manifestation of a cystic structure on radiographic imaging. In this overview, we not only explore the normal development of the bony labyrinth in mice but also present our observations on otolith mineralization. Furthermore, we investigated the specifics of bony labyrinth and otolith mineralization in Slc26a4-deficient mice, which served as an animal model for IP-II. We ensured that these findings promise to provide valuable insights for the establishment of therapeutic interventions, optimal timing, targeted sites, and preventive measures when considering the management of this condition.

Combined genetic polymorphisms of the GSTT1 and NRF2 genes increase susceptibility to cisplatin-induced ototoxicity: A preliminary study.

OBJECTIVE: The genotype-phenotype relationship in cisplatin-induced ototoxicity remains unclear. By assessing early shifts in distortion product otoacoustic emission (DPOAE) levels after initial cisplatin administration, we aimed to discriminate patients' susceptibility to cisplatin-induced ototoxicity and elucidate their genetic background. STUDY DESIGN: A prospective cross-sectional study. SETTING: Tertiary referral hospital in Japan. PATIENTS: Twenty-six patients with head and neck cancer were undergoing chemoradiotherapy with three cycles of 100 mg/m2 cisplatin. INTERVENTIONS: Repetitive pure-tone audiometry and DPOAE measurements, and blood sampling for DNA extraction were performed. Patients were grouped into early ototoxicity presence or absence based on whether DPOAE level shifts exceeded the corresponding reference limits of the 21-day test interval. MAIN OUTCOME MEASURES: Hearing thresholds after each cisplatin cycle, severity of other adverse events, and polymorphisms in cisplatin-induced ototoxicity-associated genes were compared. RESULTS: Early ototoxicity was present in 14 and absent in 12 patients. Ototoxicity presence on DPOAEs was associated with greater progression of hearing loss in frequencies ≥2 kHz throughout therapy and with higher ototoxicity grades compared with ototoxicity absence. Ototoxicity was further associated with grade ≥2 nausea. Ototoxicity presence was genetically associated with the GSTT1 null genotype and G-allele of NFE2L2 rs6721961, whereas ototoxicity absence was associated with the GSTM1 null genotype. Dose-dependent progression of hearing loss was the greatest in the combined genotype pattern of GSTT1 null and the T/G or G/G variants of rs6721961. CONCLUSION: Early DPOAE changes reflected genetic vulnerability to cisplatin-induced ototoxicity. Hereditary insufficiency of the antioxidant defense system causes severe cisplatin-induced hearing loss and nausea.

High fluence in laser stapedotomy aggravates transient subjective dizziness.

BACKGROUND: Laser fenestration in stapedotomy has thermal effect to the vestibule. AIMS/OBJECTIVES: To evaluate the role of energy density (fluence) in the severity of postoperative vestibular symptoms. MATERIALS AND METHODS: The retrospective chart-review study included 84 patients with otosclerosis that underwent primary laser stapedotomy. Surgical outcomes, including nystagmus, and subjective vestibular symptoms during one-month follow-up, were compared between potassium titanyl phosphate (KTP) and CO2 laser. According to this study and literature, we assessed the relationship between laser parameters and the incidence of persistent vestibular symptoms lasting more than one week after surgery. RESULTS: The KTP and CO2 laser group included 48 and 36 patients, respectively. Fluence was different between the KTP (637 J/cm2) and CO2 (141 J/cm2) laser (p < .001). The KTP group showed gradual decrease in dizziness during one-month observation period, while the CO2 group exhibited a steep recovery curve in the first postoperative week (9 and 4 d of duration, respectively). The incidence of persistent vestibular symptoms was correlated with both fluence (r = 0.80, p = .01) and spot size (r = -0.74, p = .01). CONCLUSIONS AND SIGNIFICANCE: Appropriate setting of parameters with lower fluence is desirable for the efficiency and safety of laser stapedotomy.Abbreviations: ABG: air-bone gap; SD: standard deviation.

Detailed Clinical Features of PTPRQ-Associated Hearing Loss Identified in a Large Japanese Hearing Loss Cohort.

The PTPRQ gene has been identified as one of the genes responsible for non-syndromic sensorineural hearing loss (SNHL), and assigned as DFNA73 and DFNB84. To date, about 30 causative PTPRQ variants have been reported to cause SNHL. However, the detailed clinical features of PTPRQ-associated hearing loss (HL) remain unclear. In this study, 15,684 patients with SNHL were enrolled and genetic analysis was performed using massively parallel DNA sequencing (MPS) for 63 target deafness genes. We identified 17 possibly disease-causing PTPRQ variants in 13 Japanese patients, with 15 of the 17 variants regarded as novel. The majority of variants identified in this study were loss of function. Patients with PTPRQ-associated HL mostly showed congenital or childhood onset. Their hearing levels at high frequency deteriorated earlier than that at low frequency. The severity of HL progressed from moderate to severe or profound HL. Five patients with profound or severe HL received cochlear implantation, and the postoperative sound field threshold levels and discrimination scores were favorable. These findings will contribute to a greater understanding of the clinical features of PTPRQ-associated HL and may be relevant in clinical practice.

Three-dimensionally visualized ossification and mineralization process of the otic capsule in a postnatal developmental mouse.

Objective: We aimed to elucidate the ossification process of the otic capsule in postnatal C57BL/6 mice and depict the three-dimensional (3D) process of otoconial mineralization in vivo. Methods: The otic capsules of C57BL/6 mice were stained with alizarin red and imaged/compared using micro-computed tomography on postnatal day (P) between P0 and P8, P10, P15, and P30 and 3-4 months old (P3-4Mo). We reconstructed 3D images of the otic capsule and otoconia and measured the bone mineral density using x-ray absorptiometry on each age. Results: The 3D reconstructed otic capsule images revealed two ossification centers of the otic capsule at P0. One was observed around the ampulla of the superior semicircular canal and utricle, and the other was observed around the ampulla of the posterior semicircular canal. The cross-sectional views demonstrated that modiolar ossification developed from the base to the apex from P4 to P8. The inter-scalar septum ossified bidirectionally from the modiolus and bony otic capsule from P8 to P15. The mineralized otoconia were first detected in the utricle at P3 and saccular otoconia at P6. The density of the utricle and saccular otoconia showed different growth trends. Conclusion: To the best of our knowledge, this is the first study to demonstrate the 3D appearance of the otic capsule and otoconia in different developmental stages of mice. We also revealed that modiolar and inter-scalar septal calcification is the final event in the cochlea and that it can be susceptible to pathological conditions (cochlear congenital malformations and hereditary vestibular diseases). The unique features of the ossification process and duration may explain these pathological conditions observed in humans. Level of Evidence: 3.

Advanced Magnetic Resonance Imaging Sheds Light on the Distinct Pathophysiology of Various Types of Acute Sensorineural Hearing Loss.

OBJECTIVE: To compare the findings of magnetic resonance imaging (MRI) with advanced protocols in patients with various types of acute sensorineural hearing loss (ASNHL). STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Two hundred eighty-seven patients with ASNHL. INTERVENTIONS: All patients underwent MRI scanning, including heavily T2-weighted three-dimensional fluid-attenuated inversion recovery before and 4 hours after the intravenous administration of gadolinium contrast medium (delayed 3D-FLAIR). A hybrid of the reversed image of the positive endolymph signal and the native image of the perilymph signal image was constructed to visualize the endolymphatic space. RESULTS: The detection rates of abnormal MRI findings vary significantly among different types of ASNHL. A hyperintense signal on delayed 3D-FLAIR was observed in all patients with intralabyrinthine schwannoma or vestibular schwannoma and 20.5% of patients with idiopathic sudden sensorineural hearing loss (ISSNHL) but was rarely observed in definite Ménière's disease (MD, 2.6%). In contrast, endolymphatic hydrops (EH) was frequently observed in patients with definite MD (79.5%) but was observed much less frequently in patients with ISSNHL (11.0%). In patients with cochlear MD and ALHL, detection rates of cochlear EH were similar to those with definite MD, whereas detection rates of vestibular EH were significantly lower than in patients with definite MD. CONCLUSIONS: The significantly different detection rates of abnormal MRI findings among various types of ASNHL shed light on the distinct pathophysiology of each disorder. A diagnosis based on MRI findings with advanced protocols may help select treatment strategies and provide prognostic information for patients.

Extended screening for major mitochondrial DNA point mutations in patients with hereditary hearing loss.

Hearing loss (HL) is the most common sensory disorder in humans. Many patients with mitochondrial diseases have sensorineural HL (SNHL). The HL of these patients manifests as a consequence of either syndromic or nonsyndromic mitochondrial diseases. Furthermore, the phenotypes vary among patients even if they are carrying the same mutation. Therefore, these features make it necessary to analyze every presumed mutation in patients with hereditary HL, but the extensive analysis of various mutations is laborious. We analyzed 373 patients with suspected hereditary HL by using an extended suspension-array screening system for major mitochondrial DNA (mtDNA) mutations, which can detect 32 other mtDNA mutations in addition to the previously analyzed 29 mutations. In the present study, we detected 2 different mtDNA mutations among these 373 patients; m.7444G>A in the MT-CO1 gene and m.7472insC in the MT-TS1 gene in 1 patient (0.3%) for each. As these two patients had no clinical features other than HL, they had not been suspected of having mtDNA mutations. This extended screening system together with the previous one is useful for the genetic diagnosis and epidemiological study of both syndromic and nonsyndromic HL.

Epstein-Barr virus nuclear protein EBNA3C residues critical for maintaining lymphoblastoid cell growth.

Epstein-Barr virus (EBV) nuclear antigen 3C (EBNA3C) is essential for efficient conversion of primary human B lymphocytes to lymphoblastoid cell lines (LCLs) and for continued LCL growth. We used a transcomplementation assay in the context of LCLs transformed by an EBV with a conditional EBNA3C to identify the EBNA3C amino acids (aa) necessary for maintaining LCL growth. Surprisingly, we found that most EBNA3C aa were essential for continued LCL growth. Only EBNA3C mutants deleted for residues within aa 507-515, 516-620, 637-675, or 676-727 maintained full LCL growth, and EBNA3C mutants deleted for residues within aa 728-732 or 910-992 maintained slow LCL growth. In contrast, EBNA3C lacking aa 180-231, which mediate RBP-Jkappa association and are necessary for EBNA3C abrogation of EBNA2-induced transcription through RBP-Jkappa, could not support LCL growth. Furthermore, 2 EBNA3C alanine substitution mutants within aa 180-231, which were wild-type (wt) in abrogating EBNA2-mediated transcription through RBP-Jkappa, maintained LCL growth, and 2 alanine substitution mutants within aa 180-231, which were null in abrogating EBNA2-mediated transcription through RBP-Jkappa, did not maintain LCL growth. This indicates that EBNA3C regulation of transcription through RBP-Jkappa is critical to maintaining LCL growth. Several other EBNA3C functions also are critical for LCL growth, because EBNA3C mutants deleted for residues within aa 130-159, 251-506, or 733-909 were wt in abrogating transcription through RBP-Jkappa and expression level, but did not maintain LCL growth.

Tissue-Resident Macrophages in the Stria Vascularis.

Tissue-resident macrophages play an important role in clearance, development, and regulation of metabolism. They also function as sentinel immune cells, initiating inflammatory responses, clearing inflammatory debris, and maintaining homeostatic tissue environment. In the cochlea, the roles of tissue-resident macrophages include maintaining steady-state tissues, immunological defense, and repairing pathological conditions associated with noise, ototoxic drugs, aging, and various pathogens. Perivascular macrophages (PVMs) are a unique subset of tissue-resident macrophages that are closely associated with blood vessels and have unique expression markers in certain tissues. PVMs are found in the inner ear, brain, skin, liver, and retina. The origin of PVMs in the inner ear is unclear, but they are already present during embryonic development. PVMs are members of the blood labyrinth barrier and regulate blood vessel permeability in the stria vascularis, which lies on the lateral wall of the cochlear duct and is crucial for endocochlear potential formation. The cytoplasm of strial PVMs can contain pigment granules that increase in number with age. Strial PVMs are activated by the loss of Slc26a4 in the cochleae, and they subsequently phagocytose aggregated pigment granules and possibly degenerated intermediate cells. This review summarizes the current knowledge of characteristic features and proposed roles of PVMs in the stria vascularis. We also address macrophage activation and involvement of pigment granules with the loss of Slc26a4 in the cochleae.