内耳病理学研究技术的进展

内耳病理学是一门从组织形态学角度研究内耳疾病的发生原因和发展过程及其损害机制的边缘医学基础学科。内耳病理学的样品制备观察技术包括颞骨切片技术、膜迷路切片技术、耳蜗和前庭膜迷路取材铺片技术、内耳组织学和组织化学技术、内耳扫描电镜和透射电镜样品制备技术、以及电镜下的超微细胞化学技术等。通过分析各项内耳病理研究技术的发生、发展和现状，并结合实践经验和技术革新经验，深入讨论上述各项技术的优缺点和技术细节     

PCR技术对大鼠内耳膜迷路线粒体DNA的检测

目的：建立灵敏、可靠的大鼠内耳膜迷路线粒体ＤＮＡ提取和检测方法。方法：结合ＰＣＲ技术扩增ｍｔＤＮＡ编码ＮＤ１－１６ＳｒＲＮＡ基因的６０１ｂｐ片段，检测大听泡内耳膜迷路线粒体ＤＮＡ方法，并对两种ｍｔＤＮＡ获取方法进行比较。结果：采用Ｓｅｉｄｍａｎ的方法，将１只大鼠的以侧听泡内耳膜迷路作为一个样品，检测１０个样品均成功扩增出编码ＮＤ１－１６ＳｒＲＮＡ基因的６０１ｂｐ片段；而采用ＥｄｒｉｓｍｔＤＮＡ提取     

Anatomic study of maximum intensity projection of the membranous labyrinth and the internal auditory meatus - MRI scan in 16 Chinese adults

CONCLUSION: Three-dimensional reconstruction of maximum intensity projection (MIP) might document objectively, stereoscopically and directly the minute structures of the membranous labyrinth and internal auditory meatus. In this study, we establish magnetic resonance imaging (MRI) measurement criteria of the inner ear in Chinese adults. OBJECTIVE: The goal of this study was to provide an anatomic basis for otolosurgery and neurosurgery in Chinese adults. MATERIALS AND METHODS: Sixteen healthy volunteer subjects were scanned by a GE-signa 1.5T MRI scanner. All original images were transferred to an MRI workstation and all the structures of the inner ear were reconstructed, rotated at various angles and measured with an MIP program. RESULTS: Anatomic structures of the membranous labyrinth and internal auditory meatus were well demonstrated in MIP images in all volunteers. All inner ear structures including utricle, saccule, cochlear duct, internal auditory meatus and three semicircular ducts produced high intensity signals.     

Anatomic study of maximum intensity projection of the membranous labyrinth and the internal auditory meatus – MRI scan in 16 Chinese adults

Conclusion. Three-dimensional reconstruction of maximum intensity projection (MIP) might document objectively, stereoscopically and directly the minute structures of the membranous labyrinth and internal auditory meatus. In this study, we establish magnetic resonance imaging (MRI) measurement criteria of the inner ear in Chinese adults. Objective. The goal of this study was to provide an anatomic basis for otolosurgery and neurosurgery in Chinese adults. Materials and methods. Sixteen healthy volunteer subjects were scanned by a GE-signa 1.5T MRI scanner. All original images were transferred to an MRI workstation and all the structures of the inner ear were reconstructed, rotated at various angles and measured with an MIP program. Results. Anatomic structures of the membranous labyrinth and internal auditory meatus were well demonstrated in MIP images in all volunteers. All inner ear structures including utricle, saccule, cochlear duct, internal auditory meatus and three semicircular ducts produced high intensity signals.     

自身免疫性内耳病动物模型的抗内耳特异性抗体谱系分析

目的 为明确哪几种膜迷路蛋白成分参与了实验性自身免疫性内耳病（ａｕｔｏｍｍｕｎｅｉｎｎｅｒ－ｅａｒ ｄｉｓｅａｓｅ，ＡＩＥＤ）的形成。方法 以同种内耳组织抗原免疫豚鼠，建立自身免疫性内耳病动物模型。用免疫转印迹技术（Ｗｅｓｔ－ｅｒｎ ｂｌｏｔ）检测动物血液中抗膜迷路蛋白抗体。结果 豚鼠膜迷路蛋白成分复杂，ＳＤＳ－ＡＰＧＥ电泳至少可分出５种，但免疫后大多数动物（１５／２０）体内仅产生了抗６８ｋＤ和１     

迷路炎的影像学

目的 探讨迷路炎的影像学检查方法及其诊断价值.方法 观察27例31耳临床提示为迷路炎同时存在异常影像学表现的病例的高分辨率CT(high resolution CT, HRCT)及MRI图像,总结其内耳在HRCT及MRI图像上的不同改变.结果 进行了HRCT扫描的22耳中,内耳1个或多个结构表现为密度增高者6耳,密度增高且发生变形者8耳,单纯变形者1耳,内耳迷路内腔局部或完全硬化消失者7耳.在22耳中除上述改变外亦有内耳骨质缺损者4耳.进行了HRCT及MRI检查的9耳中,7耳在HRCT上可见内耳不同程度的异常改变,2耳内耳未见异常改变.MRI图像上9耳均可见内耳迷路内腔1个或多个结构T2WI信号减低或消失.行增强扫描的6耳中,4耳可见明显强化,2耳未见强化.31耳中,耳蜗受累30耳,其中仅基底周受累5耳,中顶周受累2耳,耳蜗各周均受累23耳;半规管受累26耳;前庭受累20耳;前庭窗受累18耳;蜗窗受累19耳.结论 HRCT可以较好显示骨迷路迷路炎的异常改变,MRI对于显示迷路内腔有重要价值,二者在迷路炎的影像检查与诊断中的作用是互补的,对迷路炎的临床诊断起着重要的辅助作用.     

Normal anatomy of the inner ear.

The three parts of the inner ear have been reviewed: the membranous (endolymph containing) labyrinth surrounded by the osseous (perilymph containing) labyrinth, and the otic capsule of bone that encases the osseous labyrinth. This is a brief survey of the normal anatomy, but one must always remember that the hallmark of the temporal bone is variation.     

Intermediate filaments in the newborn inner ear of the mouse

The presence of intermediate filaments in the inner ear of the newborn mouse was analyzed with immunofluorescence techniques using antibodies against the five classes of intermediate filaments: cytokeratins, vimentin, desmin, neurofilaments and glial fibrillary acid protein (GFA). Neurofilaments were found in all nerve fibers from the ganglion cell to the hair cell. In the vestibular ganglion two subpopulations of ganglion cells were identified: a minor part staining intensively with neurofilament and the major part of cells lacking this immunofluorescence. Vimentin occurred in a number of supporting structures in the membranous labyrinth, but not in vestibular or cochlear ganglion cells. Cytokeratins, desmin or GFA were not identified in the inner ear.     

Whole-body autoradiography of [3H]dihydrostreptomycin in guinea pigs and rats: the labelling of the inner ear in relation to other tissues

[3H]Dihydrostreptomycin was given intramuscularly to young pigmented guinea pigs and rats. Whole-body autoradiography, combined with densitometric measurement of the blackening of the autoradiograms, and liquid scintillation counting were used to determine the levels of radioactivity in the inner ear in relation to blood and other tissues. It was found that there was an accumulation of radioactivity in the perilymph of both the cochlear and vestibular parts of the labyrinth. The labelling of the endolymph was weak. The levels of radioactivity in the membranous linings of the labyrinth including the areas covered with the neuroepithelial structures, were about the same as in the perilymph. The general distribution pictures were characterized by a localization of radioactivity in extracellular tissues, such as cartilages and connective tissues and by strong labelling of the kidney cortex. The preferential uptake in the perilymph indicates a route by which the inner ear hair cells can be exposed to high levels of aminoglycoside antibiotics.     

Cisplatin: evaluation of its ototoxic potential

The ototoxic potential of cisplatin was analyzed in an organ culture model exposing the hair cells and other inner ear structures to cisplatin doses from 0.1 to 10 micrograms/ml. Selective hair cell degeneration was obvious at concentrations of 0.1 microgram/ml. Incubation with 1 microgram/ml caused morphologic damage in the supporting cells in both the cochlear and vestibular parts of the labyrinth. Exposure to 10 micrograms/ml during five days caused a total collapse of the membranous labyrinth. The morphologic degeneration pattern at the ultrastructural level is nonspecific, except that nuclear chromatin was either swollen and disintegrated or considerably condensed. Based on inner ear concentrations equivalent to aminoglycoside antibiotics in the range of 0.1 to 10 micrograms/ml, cisplatin is, in the in vitro model used in this study, the most ototoxic drug known. However, because of its single dose administration and long intervals between administration, clinical ototoxicity is less pronounced than that from aminoglycoside antibiotics.     

Temporal bone pathology in a case of cogan's syndrome

Cogan's syndrome (CS) presents typical and atypical types. Typically, there are episodes of non-syphilitic keratitis and audiovestibular dysfunction. Atypically, there are inflammatory changes in other eye structures and other organ systems, particularly the cardiovascular system. The temporal bone pathology in a case of CS shows changes that are similar to those observed in other autoimmune disorders associated with audiovestibular dysfunction. The following pathologic features characterize autoimmune inner ear disease: 1. acute labyrinthitis resulting in atrophy of inner ear tissues including the sense organs and their supporting structures; 2. endolymphatic hydrops; 3. focal and diffuse proliferation of fibrous tissue and bone; and 4. retrograde neuronal degeneration. These pathologic findings are consistent with an inflammatory (and possibly ischemic) attack on the membranous labyrinth.     

A new approach to visualizing the membranous structures of the inner ear - high resolution X-ray micro-tomography

CONCLUSION: Through the application of high resolution X-ray micro-tomography and a method of contrast enhancement based on en bloc staining in osmium tetroxide (OsO4), we report an approach that facilitates accurate three-dimensional (3D) reconstruction to reveal the fine structure of the inner ear. OBJECTIVES: To overcome the problems of artefacts, including tissue distortion and loss of 3D context that are inherent in existing methods that rely on manual dissection and/or histological sectioning. MATERIALS AND METHODS: A staining protocol was developed that involved the en bloc application of the OsO4 solution (2% w/v) for an extended period of time. The samples were then scanned using an X-ray micro-tomography platform and subsequent 3D visualizations were constructed. RESULTS: The digital nature of the data allowed a complete 3D contextual visualization to be constructed whereby the individual sensory structures could be seen in relation to other inner ear structures. This included a detailed anatomy of the membranous labyrinth and nerve supply including the spatial configuration of the utricular and saccular maculae. This is a new way of undertaking temporal bone histology.     

Computer-aided three-dimensional reconstruction of the osseous and membranous labyrinths

Summary In order to obtain an adequate knowledge of the stereoscopic anatomy of the temporal bone, it is very useful to make three-dimensional reconstructions of the bone. By using the histological sections of a human temporal bone processed for routine evaluation, we have undertaken computer-aided reconstruction of the osseous and the membranous labyrinths, as well as the inner ear sensory organs. Reconstructions were done either separately or simultaneously. Owing to the semitransparent display function of the computer system, it was possible to observe the reconstructed membranous labyrinth through the simultaneously reconstructed osseous labyrinth, and the sensory organs through the membranous labyrinth. The results were satisfactory for understanding the spatial relationships among these structures. We also attempted computer-aided measurements of the reconstructed sensory organs and calculated the length of the organ of Corti and the angle between the saccular and the utricular maculae.     

3 Tesla delayed contrast magnetic resonance imaging evaluation of Ménière's disease

OBJECTIVE: To determine whether 3 Tesla (T) magnetic resonance imaging (MRI) with delayed contrast imaging has sufficient anatomic resolution to image the intracochlear fluid spaces (i.e., the scala tympani, scala media, and scala vestibuli) of the inner ear and identify endolymphatic hydrops in vivo. STUDY DESIGN: Four normal subjects underwent 3T MRI scanning after the administration of gadodiamide intravenous (IV) contrast. MRI region of interest signal intensity was used to determine the diffusion of gadodiamide into the perilymphatic fluid spaces over time. Seven subjects with unilateral Ménière's disease underwent 3T MRI 4 hours after administration of gadodiamide IV contrast agent. RESULTS: All four normal subjects demonstrated perilymphatic enhancement by 4 hours postinjection. Loss of definition of the membranous cochlea was noted in five of the seven subjects with Ménière's disease. Precise definition of the scala media could not be achieved with this imaging protocol. CONCLUSION: Delayed contrast imaging of the inner ear with 3T MRI revealed in vivo changes of the membranous labyrinth consistent with unilateral Ménière's disease.     

Identification of previously "undetectable" abnormalities of the bony labyrinth with computed tomography measurement

BACKGROUND: In patients with congenital sensorineural hearing loss (SNHL), a computed tomography (CT) scan of the temporal bone identifies inner ear malformations in approximately 25%, whereas the inner ear is grossly normal to visual inspection in the remaining 75% of the patients. In the latter group, the hearing loss is often attributed to radiologically undetectable abnormalities of the membranous labyrinth. However, subtle bony malformations may be missed because visual inspection alone is insensitive for detection. OBJECTIVE: To test the hypothesis that there are subtle bony abnormalities of the inner ear in patients with SNHL who are radiologically deemed to have normal otic bone, using standardized measurements of the inner ear. STUDY DESIGN: Retrospective review. METHODS: Measurements of the cochlea, vestibule, and semicircular canals (SCCs) were made on axial and coronal temporal bone CT scans on 15 patients with normal hearing and 15 patients with congenital SNHL and grossly normal temporal bone CT scans. Student's t-test was performed to compare the measurements of the two groups.RESULTS All studies from the SNHL group were deemed normal by visual inspection and standardized measurements (+/-2 SD from normal). Surprisingly, there were significant differences in the measurements of the cochlea and of the SCCs between patients with and without SHNL (P <.05). CONCLUSIONS: As a group, patients with SNHL and a "normal CT scan" have significant differences in the dimensions of the inner ear. This suggests that these patients have disturbed morphogenesis of both membranous and bony labyrinth. This novel observation has important implications for understanding the etiology of SNHL.     

The effects of vascular occlusion on the human inner ear

Occlusion of the anterior vestibular artery has resulted in severe degeneration and new bone formation limited to the utricle, saccule, and superior and lateral semicircular canals. Depriving the inner ear of its main blood supply, i.e. the internal auditory artery, has resulted in severe degeneration and ossification of the entire membranous labyrinth, except the endolymphatic duct and sac. A more severe cochlear sclerosis was seen when both arterial and venous blood supplies to the cochlea were occluded. The implications of these findings on the etiology and management of inner ear disorders are emphasized.     

Magnetic resonance appearance of the inner ear after hearing-preservation surgery.

OBJECTIVE: To determine whether the appearance of the inner ear on T2-weighted follow-up magnetic resonance imaging correlates with hearing status after hearing-preservation surgery for vestibular schwannoma. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral medical center. PATIENTS: The study includes patients undergoing hearing-preservation surgery for vestibular schwannoma from 1998 to 2003. INTERVENTION: Diagnostic evaluation with magnetic resonance imaging and audiometric evaluation. MAIN OUTCOME MEASURES: Hearing results as reported in charts was correlated with appearance of membranous labyrinth on T2-weighted magnetic resonance images obtained at least 1 year after surgery. RESULTS: Twenty-nine patients were identified, 16 of whom satisfied the inclusion criteria. All 16 of the patients underwent middle fossa removal of vestibular schwannoma. Serviceable hearing according to American Academy of Otolaryngology-Head and Neck Surgery criteria was preserved in eight patients (50%). Of the eight patients without serviceable hearing, six had the cochlear nerve sacrificed at the time of surgery. All patients with serviceable hearing had normal appearing cochleovestibular signal on T2-weighted images, whereas six of eight patients (75%) with no hearing or poor hearing had abnormal low signal in the inner ear, suggesting inner ear ossification. The positive predictive value of a normal labyrinth for preserved hearing was 90%, whereas the negative predictive value of an abnormal labyrinth for no hearing was 100%. All but one patient who had the cochlear nerve sacrificed showed abnormal morphology of the labyrinth on T2-weighted magnetic resonance imaging. CONCLUSION: We describe the T2-weighted magnetic resonance findings after hearing-preservation surgery for acoustic tumor removal. Loss of inner ear signal on T2-weighted images correlates with loss of hearing postoperatively, whereas preserved inner ear signal correlates with hearing preservation after middle fossa surgery for vestibular schwannoma removal.     

Expression of aquaporins in inner ear disease

The inner ear is responsible for hearing and balance and consists of a membranous labyrinth within a bony labyrinth. The balance structure is divided into the otolith organ that recognizes linear acceleration and the semicircular canal that is responsible for rotational movement. The cochlea is the hearing organ. The external and middle ear are covered with skin and mucosa, respectively, and the space is filled with air, whereas the inner ear is composed of endolymph and perilymph. The inner ear is a fluid-filled sensory organ composed of hair cells with cilia on the upper part of the cells that convert changes in sound energy and balance into electric energy through the hair cells to transmit signals to the auditory nerve through synapses. Aquaporins (AQPs) are a family of transmembrane proteins present in all species that can be roughly divided into three subfamilies according to structure and function: 1) classical AQP, 2) aquaglyceroporin, and 3) superaquaporin. Currently, the subfamily of mammalian species is known to include 13 AQP members (AQP0–AQP12). AQPs have a variety of functions depending on their structure and are related to inner ear diseases such as Meniere's disease, sensorineural hearing loss, and presbycusis. Additional studies on the relationship between the inner ear and AQPs may be helpful in the diagnosis and treatment of inner ear disease. Laryngoscope, 130:1532–1539, 2020     

CT of the temporal bone in the study of the inner ear structures in detection of the causes of neurosensory hypoacusis

Computed tomograms of the inner ear structures (n=175) of 150 patients (age 0-75 years) with unaffected temporal bones were studied in detail. It is shown that polyposition CT of the temporal bone is a non-invasive method of visualization of the osseous labyrinth structures: cochlea, vestibule, semicircular canals, aqueducts of the labyrinth and internal acoustic meatus which are reflected on tomograms in 100% cases irrespective of the patient age. Their age-related features are analysed. CT imaging was made in 65 patients with neurosensory hypoacusis of inherited and acquired genesis. The following causes of neurosensory hypoacusis and deafness were revealed: congenital malformation of the labyrinth of Mondini type, common cavity of the labyrinth, cochlear hypoplasia, dysplasia of the vestibule and semicircular canals, a wide aqueduct of the vestibule, stenosis of the internal acoustic meatus, bulboform enlargement of the inner acoustic meatus, neurinoma (schwannoma) of the hearing nerve, Langerhans-cell histiocytosis with affection of the labyrinth capsule, atypical cholesteatoma. The detected changes in the inner ear structures determine further treatment policy.     

Inner ear changes in the ferret model for Reye's syndrome

The acute effects of influenza B, aspirin, and hyperammonemia on the inner ear were examined using the ferret model for Reye's syndrome. Histopathologic examination revealed varying degrees of vacuolization in both the sensory and nonsensory endolymphatic tissues of the cochlear and vestibular membranous labyrinth. The secretory epithelial cells of the stria vascularis and the vestibular dark cells appeared to be more severely affected, as demonstrated by the presence of an extensive number of intracytoplasmic vacuoles. The cells of the perilymphatic tissues appeared to be unaltered. Although all neuroepithelial regions of the inner ear appeared to be altered, an unexpected observation was that only the inner hair cells of the organ of Corti were pathologically affected. These results suggest that metabolic and virus-induced derangements may alter inner ear microhomeostasis in patients with Reye's syndrome and may potentially result in loss of hearing in such patients.