Geographical differences in the composition of tetrodotoxin and 5,6,11-trideoxytetrodotoxin in Japanese pufferfishes and their origins.

Tetrodotoxin (TTX)-bearing fish are thought to accumulate TTXs in their bodies through a food chain that begins with marine bacteria. However, the mechanism of TTXs transfer between prey and predators in the food chain remains unclear and the reasons for regional differences in pufferfish toxicity are also unknown. To investigate these matters, we collected juveniles of four species of pufferfish, Takifugu alboplumbeus, Takifugu flavipterus, Takifugu stictonotus, and Chelonodon patoca, from various locations in the Japanese Islands, and subjected them to liquid chromatography-tandem mass spectrometry analysis for TTX and its analog 5,6,11-trideoxyTTX (TDT).

Feasibility and limitations of head MRI in patients with cochlear implants.

Objective: Cochlear implants (CIs) were noncompatible with magnetic resonance imaging (MRI) initially; however, recently, implants have become available that are compatible with MRI without the need for magnet removal or bandage fixation. The images produced by MRI scans are sometimes deteriorated by artifacts and are not clinically useful. In this study, we discussed the size differences of such artifacts with respect to the imaging modality and sequences with their clinical validity.

Tetrodotoxin Detection in Japanese Bivalves: Toxification Status of Scallops.

Tetrodotoxin (TTX), or pufferfish toxin, has been frequently detected in edible bivalves around the world during the last decade and is problematic in food hygiene and safety. It was reported recently that highly concentrated TTX was detected in the midgut gland of the akazara scallop Chlamys (Azumapecten) farreri subsp. akazara collected in coastal areas of the northern Japanese archipelago.

Reading comprehension skill in English as a second language of Japanese middle school students with cochlear implants.

Objectives: To assess the English reading comprehension skill of Japanese middle school students with cochlear implants (CIs).

Materials And Methods: The subjects were pre- or perilingually deafened CI recipients between seventh and ninth grades (age 12-15 years). English reading comprehension skill was evaluated using the Norm Referenced Test developed for Japanese students.

The actual state of and factors for speech perception ability in adult cochlear implant wearers.

Purpose: To elucidate the status of speech perception ability in cochlear implant wearers with unknown deafness causes.

Materials And Methods: We extracted 1095 patients between January 1, 1986, and December 31, 2019; among them, there were 418 first-surgery adults who wore implants made by Cochlear. Finally, we included 204 patients (69 males and 135 women) without cochlear morphological abnormalities.

Modeling gap junction beta 2 gene-related deafness with human iPSC.

There are >120 forms of non-syndromic deafness associated with identified genetic loci. In particular, mutation of the gap junction beta 2 gene (GJB2), which encodes connexin (CX)26 protein, is the most frequent cause of hereditary deafness worldwide. We previously described an induction method to develop functional CX26 gap junction-forming cells from mouse-induced pluripotent stem cells (iPSCs) and generated in vitro models for GJB2-related deafness.

Generation of two induced pluripotent stem cell lines from PBMCs of siblings carrying c.235delC mutation in the GJB2 gene associated with sensorineural hearing loss.

The gap junction beta-2 (GJB2) gene is the most common genetic cause of hereditary deafness worldwide. Especially, the 235delC mutation in GJB2 is most prevalent in East Asia. In this study, we generated two iPSC lines from PBMCs of siblings carrying homozygous 235delC mutation which exhibits an audiometric phenotype of profound hearing loss.

The Prevalence and Clinical Characteristics of -Associated Autosomal Dominant Hearing Loss.

is well known as a causative gene for autosomal dominant mid-frequency hearing loss observed in various populations. In this study, we performed next-generation sequencing analysis of a large Japanese hearing loss cohort, including eight hundred and twelve (812) subjects from unrelated autosomal dominant hearing loss families, to estimate the prevalence and phenotype-genotype correlations in patients with mutations. The prevalence of mutations in Japanese autosomal dominant sensorineural hearing loss families was found to be 3.

Bilateral Versus Unilateral Cochlear Implantation in Adult Listeners: Speech-On-Speech Masking and Multitalker Localization.

Binaural hearing helps normal-hearing listeners localize sound sources and understand speech in noise. However, it is not fully understood how far this is the case for bilateral cochlear implant (CI) users. To determine the potential benefits of bilateral over unilateral CIs, speech comprehension thresholds (SCTs) were measured in seven Japanese bilateral CI recipients using Helen test sentences (translated into Japanese) in a two-talker speech interferer presented from the front (co-located with the target speech), ipsilateral to the first-implanted ear (at +90° or -90°), and spatially symmetric at ±90°.

Speech recognition in bilaterally cochlear implanted adults in Tokyo, Japan.

Introduction: The clinical effects of bilateral cochlear implantation (BCI) include binaural summation and better hearing under noise conditions. This study retrospectively examined the utility of BCI compared to unilateral cochlear implantation (CI) in adults.

Patients And Methods: We investigated 34 adults who underwent BCI, comparing speech recognition between BCI and first CI under silent and noise conditions.

[Subjective evaluation of cochlear implants through a questionnaire survey in 100 long term adult cochlear implant users].

The satisfaction level is one of the important parameters to evaluate the effectiveness of cochlear implant (CI) in adult CI users. The purpose of this study is to investigate what factor improves the satisfaction level in adult CI users. Questionnaires were used to evaluate the items concerning the satisfaction level.

Volume of the epitympanum and blockage of the tympanic isthmus in chronic otitis media: a human temporal bone study.

Hypothesis: To compare the differences in the epitympanic bony volume and the area of the tympanic isthmus (TI) in human temporal bones (HTBs) with chronic otitis media (COM) having epitympanic involvement and those without COM.

Background: TI is crucial for mastoid and epitympanic ventilation. Previous studies demonstrated that the area of TI was related to the degree of HTBs pneumatization and that COM caused suppressed pneumatization of the middle ear, decreasing volume.

Changes in the subcellular distribution of microtubule-associated protein 1B during synaptogenesis of cultured rat cortical neurons.

Microtubule-associated protein 1B (MAP1B) is expressed mainly in the brain during early development and plays important roles in the regulation of microtubule dynamics which is essential to neurite outgrowth and elongation. Recent studies report, however, that MAP1B persists in some areas of mature brain where it may serve functions other than microtubule-binding, in some cases possibly as a transmembrane protein. To understand the entire aspect of MAP1B function, we investigated the expression and subcellular localization of MAP1B during the course of synaptogenesis in cultured rat cortical neurons.