Scanning electron microscopy of the human cochlea — the stria vascularis

Summary The endolymphatic surface of the stria vascularis from normally hearing human ears has been studied with the scanning electron microscope. The cells in contact with the endolymph usually have a hexagonal-shaped surface and possess many microvilli, whilst depressions or pits are rarely seen. There is marked heterogeneity of these cells with variations in the size of the cells and the number of microvilli present on each cell.A transitional zone occurs between the stria vascularis and the spiral prominence. The surface of the cells of the transitional zone are larger and elongated whilst the cells of the spiral prominence have a smaller and more regular appearance.This work has been supported by grants from the Medical Research Council of Great Britain and from the Merseyside Regional Health Authority     

豚鼠耳蜗盖膜的扫描电镜观察

目的为了更好地理解耳蜗盖膜在听觉产生过程中的作用.方法用扫描电子显微镜观察豚鼠耳蜗盖膜的超微结构.结果在盖膜上表面观察到许多纤维网,相应与内毛细胞静纤毛顶部接触的部位有一条带状结构,在耳蜗的基底圈盖膜的下面观察到外毛细胞静纤毛的压迹,外毛细胞静纤毛的W型印在盖膜下面也形成W型的压迹.结论根据扫描电镜观察的结果讨论了盖膜与内、外毛细胞之间的接触在听力形成的作用.     

The three-dimensional fibrillar arrangement of the basilar membrane in the mouse cochlea

The three-dimensional fibrillar arrangement of the basilar membrane in the mouse cochlea was studied using scanning electron microscopy. Fibrils of the basilar membrane were exposed by removing cellular elements of the cochlea using a sodium hydroxide maceration technique. The arrangement of fibrils in the basilar membrane was different between the pars arcuata and pars pectinata. In the pars arcuata, fibrils were arranged in radial and spiral direction, showing a woven pattern. In the pars pectinata, most of the fibrils ran in the radial direction. These findings suggest that the vibration pattern of the pars arcuata and pars pectinata is different when the basilar membrane vibrates.     

Scanning electron microscopy of the human cochlea — Postmortem autolysis artefacts

Summary Changes in the ultrastructure of the cochlea due to postmortem autolysis make the assessment of the normal or damaged anatomy difficult. Three methods of preserving the human cochlea were compared on the basis of the state of preservation of the sensory cell hairs of the organ of Corti as seen in the scanning electron microscope. Perfusion of the perilymphatic space with a glutaraldehydeformaldehyde fixative within 40 min of death gave preservation as good as that seen in animal studies. Injecting formalin into the middle ear within 40 min of death allowed artefacts to develop when compared with the control ear which had been perfused with fixative. Refrigeration and early removal of the temporal bone gave poor preservation of surface structures.This work has been supported by grants from the Medical Research Council of Great Britain and by the Merseyside Regional Health Authority     

Tracheal Transplantation: Cytological Changes Studied by Scanning and Transmission Electron Microscopy in the Rabbit

Objectives Our goal was to offer a comprehensive cytological study of the changes in the trachea after experimental transplantation of the organ. Study Design Autografting of four tracheal rings was done in rabbits and tracheal samples were observed by electron microscopy from 1 week to 6 months after the surgery was performed. Methods Transmission and scanning electron microscopy were used to investigate the fine structure of tracheal samples of rabbits submitted to autotransplantation, and quantitative methods were used to compare several cytological parameters of the different groups of animals. Results We found that tracheal autografting was associated with acute injury of ciliated cells expressed by loss of more than 90% of cilia density on the tracheal epithelium 1 week after the transplantation was performed. The loss of cilia was balanced by an increase in mucous cells present on the tracheal lumen. Recovery of ciliated cells was observed 1 month after the tracheal autografting was performed. In contrast, only mild cytological modifications were seen in the cartilage tissue of the autografted trachea during the first weeks of transplantation; the structural alterations of the cartilage progressed up to the third month after transplantation, resulting in a moderate tracheal stenosis. Conclusions The data indicate that 1) autotransplantation of four tracheal rings is a viable surgical procedure; 2) tracheal grafting causes severe acute changes of the epithelium that are, however, reversible in nature; whereas 3) the initial mild alterations induced by the autografting in the cartilage may evolve into tracheal stenosis.

1 * Although the authors carried out the study they planned, it appears that their experiment was not well thought out from the onset. The clinical goal is to be able to transplant segments of trachea of two or more tracheal rings. In this procedure, as in most true transplants, one must expect some element of ischemia time, temperature changes (usually hypothermia), alterations in the dynamics of blood flow resulting from the inevitable sympathectomy, and the significant effects of lymphatic disruption. Virtually none of these effects were simulated in the “autotransplantation” carried out in this study. Thus, the study provides us with little practical clinical information and is useful primarily as a preliminary step in studying the effects of true transplantation.—Reviewer's Commentary

     

The cochlea of the spontaneously diabetic mouse

Summary We used transmission electron microscopy to examine the cochleae of non-obese diabetic mice as animal models for human type I or non-insulin-dependent diabetes mellitus. Pathological changes were observed in the organ of Corti of the basal turn and in the stria vascularis of each turn. Major findings in the stria vascularis were protrusion or condensation of marginal cells, swelling of intermediate cells, and widening of the intercellular spaces. Principal findings in the organ of Corti involved degenerative changes of the outer and inner hair cells and replacement of hair cells by supporting cells. No prominent pathological changes were observed in the capillaries. The possible mechanism of diabetic involvement in cochlear pathology is discussed.     

Scanning electron microscopy of the human cochlea — The organ of Corti

Summary The surface of the organ of Corti from normally hearing adult humans has been examined with the scanning electron microscope. It is possible to construct cytocochleograms and to derive a regression line with confidence limits to represent the distribution of the sensory hair cells. Examining individual hair cells more closely, the number of cilia on each hair cell, decreased linearly with distance, from the base of the cochlea. However, the length of the longest cilia on each outer hair cell increased linearly with distance.This work has been supported by grants from the Medical Research Council of Great Britain and by the Mersey Regional Health Authority     

Scanning electron microscopy of the human submandibular gland

Summary We examined human submandibular gland parenchyma by scanning electron microscopy after removal of connective tissue components by HCl hydrolysis. Stellate-shaped myoepithelial cells and basal infoldings were clearly seen, indicating active function of the gland.     

Electron microscopic atlas of the simian cochlea

An electron microscopic atlas of simian cochlear duct structures is presented with the hope that it may help to clarify certain questions of structural-functional relationships. Emphasis is placed on structures directly involved in sensory transduction and in synaptic transmission, at afferent and efferent nerve fiber terminals. A brief discussion is included as an introduction to the possibilities of interpretation of electron microscopic data. Orientation of electron micrographs is assisted by means of numerical coding on light microscopic photographs, and by means of a diagram which combines electron microscopic and light microscopic data.     

高压氧联合金纳多治疗突发性聋

目的：探讨金纳多联合高压氧治疗突发性聋的效果。 方法: 将50例突发性聋患者随机分为治疗组和对照组, 比较两组治疗前后平均听阈、血气分析及眼底循环监测结果。结果:两组治疗前后有效率、平均听阈、动脉氧分压有统计学差异,眼底微循环监测无明显改变。 结论: 金纳多联合高压氧治疗突发性聋疗效肯定,值得推广。     

突发性聋高压氧治疗的剂量探讨

观察３３例突发性聋患者在高压氧治疗不同时期，体内自由基代谢物质含量的变化。每天用０．２ＭＰａ高压氧稳压治疗４０ｍｉｎ，连续治疗２０ｄ。结果显示，经高压氧连续治疗１０ｄ，患者血浆过氧化脂质含量的增加，红细胞超氧化物歧化酶、谷胱甘肽过氧化物酶活性的下降都不明显（Ｐ〉０．０５），仅红细胞谷胱甘肽含量明显降低（Ｐ〈０．０５）；连续治疗２０ｄ后，患者血浆ＬＰＯ含量明显增高，红细胞ＳＯＤ和ＧＳＨＰｘ活性及ＧＳ     

Scanning electron microscopic study of the cat papilla neglecta

Summary The papilla neglecta in the cat vestibule was studied under a scanning electron microscope. This papilla appears as a small mound of cells on the utricle near the posterior semicircular canal crista. The number of sensory hair bundles on the papilla ranged from 11–64 in 7 ears examined (average, 37). Although this crista-like endorgan was regularly found in the cat, its function may not be important in that the number of sensory hair cells is only 1/150 of those counted on guinea pig posterior semicircular canal crista.This study was partly supported by U.S.P.H.S. Research Grant No. NS 10412-03The authors are deeply indebted to Professor Jun-Ichi Suzuki (Teikyo University) for his encouragement in this study. Mr. Dominic W. Hughes kindly helped in English compilation.     

Scanning and transmission electron microscopic findings in cilia from human nasal turbinate and sinus mucosa following respiratory infection

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to study the ultrastructure of human respiratory cilia in 34 patients with chronic or recurrent respiratory infections and 11 control patients. Specimens of pathological mucosa were taken from 12 maxillary sinuses and 22 middle turbinates. Control tissues were taken from middle turbinates or from sphenoid sinuses during transsphenoidal pituitary surgery. Findings in control tissues or specimens with minimal amounts of pathological findings showed that TEM and SEM findings correlated well. TEM revealed axoneme structure better, while much larger populations of cilia could be studied three-dimensionally with SEM. SEM also was the better study when cilia orientations or lengths were evaluated. Optimal examination of ciliary ultrastructure required both TEM and SEM studies.     

Scanning electron microscopic studies of the nasal blood vessels

Summary Current histological and transmission electron microscopic techniques are insufficient for studying all different aspects of vascular morphology. As a result, we have used scanning electron microscopy (SEM) to examine nasal blood vessels. In our present studies the nasal septa of 15 rabbits were fixed by vascular perfusion, dried by the critical point method and coated with gold for SEM studies. Lower magnifications of specimens using this method show the tissue arrangement in the nasal septum. In higher magnifications the different vessels can be distinguished by their morphological features. The course of the vascular structures can be obverved as well as the junctions between the different vessels. Our results indicate that different morphological techniques must be combined to understand the endonasal vasculature.     

Ultrastructural localization of gentamicin in the cochlea

The ultrastructural distribution of gentamicin in the cochlea was investigated immunocytochemically. Specific labeling was restricted to the organ of Corti, in particular to the outer and inner hair cells, the Deiters' cells, Hensen's cells and the tympanic layer cells of the basilar membrane. Other cochlear tissues did not demonstrate any labeling. At the subcellular level, gentamicin was found in lysosomes, multivesicular bodies and small tubules and vesicles.

A model is proposed in which it is hypothesized that gentamicin is internalized by endocytotic vesicles and is transferred to the lysosomal compartment as well as to the endoplasmic reticulum and Golgi complex.     

Contact between the tectorial membrane and the cochlear sensory hairs in the human and the monkey

European Archives of Oto-Rhino-Laryngology - The surface structure of the organ of Corti and the overlying tectorial membrane were studied in human and monkey cochleas under a scanning electron...     

Scanning electron microscopy of human ossicles

Summary Human middle ear ossicles removed from cadavers and during surgical procedures have been examined with scanning electron microscope (SEM).Two kinds of bone tissue compose ossicles: periosteal and endochondral bone. Periosteal bone occurs in the form of external covering on the ossicles. In the middle of the ossicles there is endochondral bone which shows various spatial arrangement of collagen bundles. Lamellar bone occurs also in this bone around vascular channels but rarely in the form of typical osteons. Surface appearance of periosteal, coarse-fibred bone and lamellar, fine-fibred bone is almost the same.Lamellar bone is composed of coarse collagen bundles arranged tightly in the rows. The space between the rows is filled by fine fibres which link the coarse bundles.     

Scanning electron microscopy of cochlear blood vessels in the mouse

Summary Resin replicas of the microvasculature of the cochlear lateral wall of the mice were studied by scanning electron microscopy. The vascular system of the mouse cochlea showed a similar architecture to that of the guinea pig, cat, and rat. Several thin connecting branches were found between the vessels of the osseous spiral lamina and the cochlear lateral wall at the apical end. The apical turn and the basal part of the lower basal turn were innervated by several radiating arterioles originating from a single stem arteriole. The hook portion and the apical end had a particular vascular meshwork different from other parts of the cochlea.     

强噪声暴露后大鼠听觉电生理及形态学改变

目的:观察强噪声暴露后大鼠听觉电生理及形态学的改变,为探讨噪声性聋的发病机制提供实验依据.方法:大鼠随机分为对照组和实验组,实验组暴露于中心频率为4 kHz的窄带噪声中,给声强度为120 dBSPL,暴露时间为4 h.观察2组听觉脑干诱发电位(ABR)及耳蜗形态学的变化.结果:实验组出现ABR反应阈上升,与对照组比较差异有统计学意义(P<0.01);暴露后第1天,基底膜铺片经DNA荧光染料碘化丙锭染色后示;实验组3排外耳毛细胞(OHC)中可出现不同的毛细胞细胞核形态变化(正常、凋亡、坏死和缺失),而第21天未见明显的细胞凋亡;OHC的缺失2组差异有统计学意义(P<0.01),螺旋神经节细胞计数2组差异无统计学意义(P>0.05).扫描电镜示;实验组OHC纤毛异常(散乱、倒伏)及OHC的缺失,以第3排OHC最严重.结论;所应用的强噪声能引起大鼠听觉系统的损害,产生永久性阈移(PTS).该噪声条件下,耳蜗毛细胞的死亡模式在暴露后早期包括凋亡和坏死,而晚期则主要是坏死;PTS的产生可能和OHC纤毛异常及OHC的缺失有关.     

Scanning electron microscopy of the normal human cochlea

Preservation of the fine structures of the human cochlea has been achieved by perfusing the cochlea with fixative shortly after death. Following the dissection of the temporal bone the surface of the organ of Corti and stria vascularis has been examined in the scanning electron microscope. The surfaces of the inner and outer hair cells can be seen and the stereocilia projecting from their surfaces closely examined. The number and length of the stereocilia of the outer hair cells changes linearly with distance along the cochlear duct. The surface of the stria vascularis is similar to that seen in other animals.