Hiroko Koda

Facial dismasking flap for removal of tumors in the craniofacial region.

Objective: This study was aimed at estimating the usefulness of the facial dismasking flap for craniofacial surgery.

Bilateral sudden deafness caused by diffuse metastatic leptomeningeal carcinomatosis.

*Department of Otolaryngology, Tokyo Metropolitan Health and Medical Treatment Corporation Okubo Hospital; ÞDepartment of Otolaryngology, Tokyo Metropolitan Geriatric Hospital, Tokyo; þDepartment of Otolaryngology, Jichi Medical School Omiya Medical Center, Saitama; §Department of Pathology, Tokyo Medical and Dental University, Tokyo; kDepartment of Otolaryngology, Yamanashi University, Yamanashi; and ¶Department of Otolaryngology, Tokyo Medical and Dental University, Tokyo, Japan

Quantitative cellular level analysis of mitochondrial DNA 3243A > G mutations in individual tissues from the archival temporal bones of a MELAS patient

CONCLUSION We could represent the first quantitative analysis of the mutation rate at the cellular level in human inner ear of a patient with MELAS (mitochondrial encephalopathy, lactic acidosis and stroke-like episodes) by combining laser capture microdissection (LCM) and quantitative real time PCR. OBJECTIVES We previously reported combining LCM and PCR to isolate mtDNA from the cells of specific tissues within a human archival celloidin-embedded temporal bone section without known otological history. Using this method, we quantitatively analyzed the rate of mtDNA 3243A > G mutation in the inner ear of a MELAS patient, and examined the correlation of the mutation rate at the cellular level and their histopathological condition. METHODS We extracted each inner ear organs using LCM from temporal bone sections of a MELAS patient, and studied the mutation rate, which was calculated as the ratio of the amount of mutant mtDNA to the total mtDNA. RESULTS We found that the mtDNA mutation rate was high in spiral ganglion cells and the saccular macula, but was comparatively low in hair cells of the organ of Corti, the stria vascularis and the facial nerve. With the exception of the stria vascularis, there was a good correlation between the mutation rate and the histological findings.

Quantitative analysis of mRNA in human temporal bones.

Conclusion. Well-preserved mRNA could be extracted from frozen human inner ears. Therefore, this study demonstrates that analysis of mRNA could be performed to study the molecular mechanisms of inner ear disorders using human specimens. Objectives. Analysis of RNA as well DNA is requisite to study the molecular mechanisms of inner ear disorders. Methods of isolating RNA from experimental animals have been established, while isolation of RNA from human inner ears is much more challenging. In the present study, we demonstrate a method by which messenger RNA (mRNA) was extracted from human inner ears and quantitatively analyzed. Materials and methods. COCH mRNA as well as GAPDH mRNA was extracted from membranous labyrinths dissected from three formalin-fixed and three frozen human temporal bones, removed at autopsy. The length of COCH mRNA and quantity of GAPDH mRNA was compared between the two groups by quantitative RT-PCR. Results: COCH mRNA could be amplified as much as 976 bp in all three frozen specimens. By contrast, it was amplified to 249 bp in two of the three formalin-fixed specimens, with no amplification observed in the remaining. The quantity of amplifiable GAPDH mRNA in the formalin specimens was only 1% of that of the frozen specimens.

RNA analysis of inner ear cells from formalin fixed paraffin embedded (FFPE) archival human temporal bone section using laser microdissection--a technical report.

OBJECTIVE Molecular analysis using archival human inner ear specimens is challenging because of the anatomical complexity, long-term fixation, and decalcification. However, this method may provide great benefit for elucidation of otological diseases. Here, we extracted mRNA for RT-PCR from tissues dissected from archival FFPE human inner ears by laser microdissection. METHODS Three human temporal bones obtained at autopsy were fixed in formalin, decalcified by EDTA, and embedded in paraffin. The samples were isolated into spiral ligaments, outer hair cells, spiral ganglion cells, and stria vascularis by laser microdissection. RNA was extracted and heat-treated in 10 mM citrate buffer to remove the formalin-derived modification. To identify the sites where COCH and SLC26A5 mRNA were expressed, semi-nested RT-PCR was performed. We also examined how long COCH mRNA could be amplified by semi-nested RT-PCR in archival temporal bone. RESULTS COCH was expressed in the spiral ligament and stria vascularis. However, SLC26A5 was expressed only in outer hair cells. The maximum base length of COCH mRNA amplified by RT-PCR was 98 bp in 1 case and 123 bp in 2 cases. CONCLUSION We detected COCH and SLC26A5 mRNA in specific structures and cells of the inner ear from archival human temporal bone. Our innovative method using laser microdissection and semi-nested RT-PCR should advance future RNA study of human inner ear diseases.

Long-term result of meatoplasty using inferiorly based retroauricular island pedicle flap for external auditory canal stenosis

OBJECTIVE To characterize the long-term outcomes of meatoplasty using our new technique, inferiorly based retroauricular island pedicle flap for external auditory canal (EAC) stenosis. METHODS A long-term clinical analysis of meatoplasty for nine patients (mean age, 33 years; age range, 8-64 years) with stenotic EAC was performed. The follow-up period after meatoplasty ranged from 5 years to 14 years, with a mean duration of 8.4 years. We compared preoperative and postoperative otoscopic findings, high-resolution computed tomographic (CT) images of the EAC, and hearing levels. RESULTS Otoscopic examinations demonstrated widened EAC in eight of the nine patients. There was a significant increase in the size of the EAC on postoperative CT examinations when compared with the preoperative state. The hearing outcome in all patients was variable. The postoperative air-bone gap (ABG) was closed to 10dB or less in two cases, while the other seven cases showed ABG ranging from 15.0dB to 57.5dB. CONCLUSIONS We performed meatoplasty using inferiorly based retroauricular island pedicle flap for nine patients with EAC stenosis and eight of the nine patients demonstrated satisfactory patent EAC during a mean follow-up of 8.4 years.

Clinical Characteristics of Audio-vestibular Impairment in Ménière's Disease: Does Vestibular Function Deteriorate in Accordance with Cochlear Function?

The clinical course of Ménières disease and the outcomes of functional examinations were found to be correlated, and a difference was found between the progressions of vestibular and cochlear dysfunction. Neither the total number of definitive vertiginous spells nor the duration of illness correlated significantly with the degree of audio-vestibular dysfunction. In contrast, frequent vertiginous spells were clearly associated with preservation of audio-vestibular function. Moreover, the clinical characteristics of those patients who experienced less than one definitive vertiginous spell per year were distinct from those of other patients, although both groups showed the typical symptoms of Ménières disease.