Anatomy of the chinchilla bulla and eustachian tube: I. Gross and microscopic study

The middle ear mucosa and eustachian tube of the normal chinchilla were studied quantitatively and under light microscopy to determine the distribution of each cell type of the lining epithelium and subepithelial gland. The middle ear mucosa consisted of columnar epithelium, cuboidal epithelium, and squamous epithelium. The lining epithelium of the eustachian tube was ciliated pseudostratified columnar epithelium. These epithelia were composed of ciliated, secretory, nonciliated (nonsecretory), and basal cells. The density of the ciliated cells was highest in the columnar epithelium area of the transitional zone of the middle ear mucosa. However, the density of the secretory cells was highest in the pharyngeal orifice of the eustachian tube. The nonciliated cell density was highest in the squamous epithelium area of the middle ear mucosa and decreased progressively toward the tympanic orifice of the eustachian tube. In the eustachian tube, the nonciliated cell density was highest in the pharyngeal portion of the eustachian tube, especially in the upper portion of the lateral wall. The subepithelial glands were tubuloacinar mixed glands composed of serous demilunes and mucous acini. The glands were localized primarily in the pharyngeal orifice and pharyngeal portion of the eustachian tube, and their ductal openings were present primarily in the inferior portion of the eustachian tube.     

Tissue culture of middle ear epithelium of the guinea pig--differences of the cellular growth activity in the middle ear cavity using collagen gel culture method

Primary tissue culture system from the middle ear and the tracheal epithelium of the guinea pig was established using collagen gel method. The cultured epithelium was studied by phase-contrast microscopy, light and scanning electron microscopy. The outgrowth area of the epithelium was quantitatively measured for period of up to ten days. In the middle ear cavity, the mucosal explants were sampled from various sites in order to compare their differential and proliferative activities. The mucosal explants attached on collagen substrates were composed of ciliated, non-ciliated, goblet and basal cells. This basic structure was similar to the natural middle ear epithelium. The ciliated cells showed well organized cilia. Most of the outgrowth cells devoid of fibroblastic cells in the monolayer were polygonal shaped with numerous microvilli. The morphology of the outgrowth cells changed from columnar or cuboidal to squamous shapes in the area away from the explants. There was a correlation between the distribution of the ciliated cells in the outgrowths and these in the explants. The explants with columnar or cuboidal ciliated epithelia sampled from the opening of the eustachian tube or its neighborhood formed more than eightfold outgrowth sheets in vitro. This is comparable to tracheal epithelia. On the other hand, the explants with simple squamous epithelia sampled from the area distal to the eustachian tube showed about fourfold proliferative activity. We concluded that this culture system would be useful for the study of cellular multiplication and differentiation mechanisms of the respiratory tract epithelium.     

Experimental induction of middle ear cholesteatoma in rats

We induced cholesteatoma in two groups of rats by instilling different concentrations of propylene glycol into the middle ear cavity. Fifteen rats were exposed to 50% propylene glycol (group I), while pure propylene glycol was applied to six others (group II). The group I rats were killed 1 month after instillation. Seven of the 15 showed cholesteatoma in the middle ear with accumulation of keratin debris. The group II rats were killed 3 months after instillation. All six animals showed inflammation in the experimental ears, and five of the six experimental ears showed cholesteatoma in the middle ear cavity. Six experimental ears in group I and five in group II revealed retraction of the tympanic membrane, possibly due to eustachian tube obstruction. Bone resorption was seen along with cholesteatoma and inflammatory cells and osteoclasts in the middle ear of all 11 of these rats. The seventh cholesteatoma of group I can be classified as a microcholesteatoma, a pearl-like cyst within the tympanic membrane. The microcholesteatoma was formed by an invasion of basal cells from the tympanic epidermis and the proliferation of these cells in the fibrous layer of the tympanic membrane. Our findings suggest that cholesteatoma in the middle ear cavity is a response to the inflammation produced by high concentrations of propyleme glycol.     

Developmental anatomy of the eustachian tube and middle ear in mice.

PURPOSE: It is generally accepted that the development of the tubotympanum has significant bearing on the susceptibility to ear infection. A detailed study of the differentiation of ciliated cells in secretory elements will be useful in understanding both the normal physiology and the pathology of the tubotympanum. METHOD: Serially sectioned temporal bones of 76 mice ranging from gestational age day 11 to postnatal day 21 were examined microscopically. RESULTS: During the period of gestation, the tubotympanic recess was formed at the 12th day and began to extend to form the middle ear between the 13th and 14th days. A rapid increase in the volume of the tubotympanic recess was observed between the 15th and 16th days when a definitive division of the tubotympanic recess into the eustachian tube and middle ear cavity was observed. Postnatally the tubotympanum attained an adult form around day 9, and the maximum change of middle ear volume was noted on day 11, when the mesenchymal tissue in the middle ear cavity disappeared completely. Development of the ciliated cells was observed concurrently in both the eustachian tube and middle ear on the 16th gestational day, one day earlier than the appearance of the epithelial secretory cells in both the eustachian tube and middle ear. The number of ciliated cells and secretory cells increased rapidly after birth. Tubal glands were well developed with evidence of secretory activity around the time of birth. CONCLUSIONS: Based on these findings, one can conclude that the mucociliary defense system starts to develop during the fetal stage and is well established immediately after birth.     

The role of middle ear effusions and epidermal growth factor in cholesteatoma formation in the gerbilline temporal bone

To study the process of aural cholesteatoma formation, we used gerbilline temporal bones to examine histologically the early stages of spontaneous cholesteatomas associated with experimentally induced otitis media with effusion (OME) following electric cauterizations of the eustachian tube. Epidermal growth factor (EGF) was then localized immunohistochemically in the pars flaccida of normal ears and the forming spontaneous cholesteatomas. Findings in the ears with the early spontaneous cholesteatomas were effusion inside the pars flaccida and hypertrophy and hyperkeratosis of the pars flaccida. Findings in the ears with experimental OME involved an effusion in the whole middle ear cavity as well as hypertrophy and hyperkeratosis in both the pars flaccida and pars tensa. The incidence of ear drum changes was higher in the experimental OME group than in control animals without cauterization. EGF was localized in the mucous layer of normal drums, the mucous layer and lamina propria of drums with hypertrophy alone, and all lalers in drums with hypertrophy and hyperkeratosis. EGF was especially positive in the cytoplasms of transformed cuboidal cells. These findings suggest that EGF within the transformed mucous layer may play an important role as a biochemical factor in developing cholesteatomas.     

Direct measurement of middle ear pressure through the eustachian tube

We report a method for measuring middle ear pressure through the eustachian tube. We used a 1-mm-diameter micro-tip catheter pressure transducer (Mikro-tip) and inserted this into the tympanic cavity through the eustachian tube. In preliminary studies, we measured four normal ears, two ears with tubal dysfunction, one ear with a dry perforation and 13 ears with otitis media with effusion (OME). Among those ears with OME, three showed negative middle ear pressure, three slight positive pressure and one normal pressure. These findings suggest that our transtubal method is reliable and useful for measuring middle ear pressure.     

Direct measurement of middle ear pressure through the eustachian tube

Summary We report a method for measuring middle ear pressure through the eustachian tube. We used a 1-mm-diameter micro-tip catheter pressure transducer (Mikro-tip) and inserted this into the tympanic cavity through the eustachian tube. In preliminary studies, we measured four normal ears, two ears with tubal dysfunction, one ear with a dry perforation and 13 ears with otitis media with effusion (OME). Among those ears with OME, three showed negative middle ear pressure, three slight positive pressure and one normal pressure. These findings suggest that our transtubal method is reliable and useful for measuring middle ear pressure.     

Experimental otitis media with effusion induced by middle ear effusion.

Experimental otitis media with effusion was induced in chinchillas by middle ear effusion, which was induced by an injection of immune complex into the tympanic cavity. To elucidate the pathogenesis of otitis media with effusion, cytologic and biochemical findings of the effusion and histopathology of the middle ear mucosa of effusion-induced chinchillas were compared with those of experimental otitis media with effusion induced by different procedures; eustachian tube obstruction, intratympanic inoculation of endotoxin, and immune reaction. No significant differences were seen in cytology, biochemistry, and histopathology among OMEs induced by these procedures. However, middle ear effusions, when compared with the corresponding sera, were proven to contain higher amounts of histamine and prostaglandin E2. These findings seem to demonstrate that middle ear effusion containing a large number of inflammatory mediators is essential for induction and prolongation of inflammatory reaction in the middle ear.     

咽鼓管咽口黏膜上皮的超微结构

目的观察咽鼓管咽口黏膜上皮的超微结构。方法取4例健康人咽鼓管咽口的组织做透射电镜标本，观察黏膜上皮的超微结构。结果咽鼓管咽口黏膜上皮为假复层纤毛柱状上皮，由纤毛柱状细胞、无纤毛柱状细胞、分泌细胞、中间细胞和基底细胞等组成，这些细胞的基部均贴附在基底膜上。可见亮颗粒分泌细胞。各类细胞可见表面活性物质板层体。黏膜下见弹性纤维和胶原纤维构成弹性纤维带。结论咽鼓管咽口黏膜上皮为假复层纤毛柱状上皮，可见亮颗粒分泌细胞，各类细胞可见板层体存在，分泌表面活性物质，弹性纤维带维持和形成咽鼓管咽口。     

Alterations of the eustachian tube, middle ear, and nose in rhinovirus infection

This study measured the changes in 64 ears of 32 adult volunteers in eustachian tube function by the nine-step test, middle ear pressure by tympanometry, and nasal patency by active posterior rhinomanometry for 18 days following type 39 or Hanks rhinovirus infection. Abnormal measures were limited to the 75% of subjects (24) with clinical illness (colds) defined by symptom scores. Two days after infection, tubal function was present in only 50% of ears (48) and 20% of persons (5), middle ear underpressures of less than -50 mm H2O were measured in 50% of volunteers (12), and decreased nasal patency was observed in 54% of those with colds (13). These changes resolved 6 to 10 days after challenge. These results support a causal relationship between viral upper respiratory tract infection eustachian tube obstruction and abnormal middle ear pressure.     

The tympano-frontal shunt: A procedure for the treatment of chronic eustachian tube insufficiency.

Eight ears with complications due to chronic eustachian tube insufficiency had insertion of a silicone rubber tympano-frontal shunt tube between the mastoid antrum and the ipsilateral frontal sinus. A one-way valve designed to open at-10 mm H₂O was placed on the tympanic end of the tube to minimize tube obstruction by ear secretions. Follow-up an average of 20 months post insertion showed six of the eight ears to have an aerated middle ear without fluid or tympanic membrane retraction or perforation.     

Different structural changes in membrana Shrapnelli in serous and purulent otitis media. An experimental study in the rat

In an animal model, production of serous and purulent effusion material was induced by blocking the Eustachian tube and cleaving the soft palate, respectively. Two and 6 weeks after the different surgical procedures, animals were sacrificed and the membrana Shrapnelli was analysed by light- and electronmicroscopy. The two types of middle ear effusion were associated with various structural changes of the membrana Shrapnelli. In serous otitis media the pars flaccida appeared fibrotic, with large dilated vessels. Sometimes its inner layer, facing the attic space, was contiguous with the investing layer of the ossicles. In purulent otitis media the pars flaccida was thickened and the inner epithelial lining was replaced by a pseudostratified squamous epithelium containing ciliated and secretory cells. Ciliated cells lining the pars flaccida appeared pathognomonic for a longstanding middle ear infection. It is inferred that the structure of membrana Shrapnelli changes under the influence of inflammatory conditions in the middle ear cavity, changes which specifically reflect the different types of otitis media.     

Antigenic as well as nonantigenic stimuli induce similar middle ear responses in the rat

OBJECTIVES/HYPOTHESIS: The observation that during otitis media many different types of micro-organisms have been cultured from effusions indicate that, once present in the middle ear cavity, most types of micro-organisms are able to trigger an inflammatory reaction leading to otitis media. The present study was designed to determine the middle ear response after injection of different substances into the middle ear cavity. STUDY DESIGN: To determine whether and to what extent an inflammatory response of the middle ear depends on the entering agent, the response in the tympanic cavity was studied by otomicroscopy and histological examination after inoculation of various substances. METHODS: Lewis rats were inoculated in transtympanic fashion either with live or heat-killed bacteria (pathogenic and nonpathogenic), Keyhole limpet hemocyanin, active charcoal, or saline. The mucosal response of the challenged middle ears was studied histologically. RESULTS: Irrespective of the inoculated substance, no essential differences in the mucosal response were found. The intensity of the inflammatory response was greater when live bacteria were inoculated. CONCLUSIONS: The present study demonstrates that any substance reaching the middle ear cavity is likely to induce otitis media. These observations emphasize the role of the eustachian tube as "porte d'entrée" in the pathogenesis of this disorder. Determination of specific aspects of the eustachian tube involved in protection or in facilitating bacterial translocation will be important for the understanding of the pathogenesis of otitis media and the subsequent development of new therapeutic strategies. In addition, elucidation of bacterial factors involved in the process of colonization and translocation will be of equal importance.     

鼻咽癌放疗后咽鼓管功能障碍的几种类型

目的：了解鼻咽癌放疗后咽鼓管功能障碍的类型及其影响。方法：对32例(50耳)鼻咽癌放疗后有咽鼓管功能障碍的患者进行常规检查、听力计检查、鼓室导抗图法检查、咽鼓管一鼓室气流动态法(TTAG)检查、咽鼓管音响法检查和内镜检查咽鼓管咽口。结果：咽鼓管异常开放2例(4耳)，患者症状较轻。咽鼓管粘连5例(7耳)，咽鼓管完全阻塞17例(27耳)，咽鼓管不全阻塞8例(12耳)，后三者症状相似，主要导致分泌性中耳炎。结论：鼻咽癌放疗后可导致不同类型的咽鼓管功能障碍，对耳功能产生损害，对其了解将有助于针对性治疗方法的确定。     

The mucosal lining of the Eustachian tube of the rat

This report deals with a microscopical study on the Eustachian tube of the rat. The tube consists of a small membranous part and a larger part which is supported by cartilage to a varying extent. The epithelial lining is composed of pseudostratified ciliated epithelium and squamous epithelium, both arranged in coherent fields, extending from nasopharynx to the middle ear cavity. The ciliated epithelium, which is continuous with the tracts of ciliated epithelium in the middle ear, provides morphological evidence for the existence of a mucociliary transport system. The part of the tube, that is lined by squamous epithelium is suggested to be involved in facilitating the passage of air. The observations made on the secretory elements refer to a different function of goblet cells and the subepithelial compound glands in Eustachian tube physiology.     

表面活性物质在分泌性中耳炎咽鼓管开放功能中的作用

目的　探讨外源性的表面活性物质在分泌性中耳炎咽鼓管开放功能中的作用。方法　通过鼓室内注入灭活的肺炎链球菌悬液 ,建立分泌性中耳炎动物模型 ,测试咽鼓管的被动开放压。结果　测试了中耳有渗液者 2 7耳和正常者 2 1耳的咽鼓管被动开放压 ,有渗液耳的被动开放压高于正常耳的被动开放压 ,分别注入外源性的表面活性剂后 ,被动开放压均降低 (P <0 .0 1)。结论　外源性的表面活性剂可以降低咽鼓管的表面张力 ,有利于咽鼓管的开放     

Ciliary activity in the in vitro tubotympanum

We have introduced a tissue culture technique in which the ciliary activity of the cultured tubotympanum can be studied. We have found that ciliated cells of the eustachian tube and middle ear lining continued a beating activity during 168 h of observation. The mean loss of activity of the ciliated cells from the eustachian tube or mucosal sites proximal to the tube was 20% or less, while that of mucosal sites distal to the tube was about 40% even after 168 h of cultivation in our culture medium of RPMI 1640. Our technique of tissue culture is available for studying the long-term effects of various therapeutic agents or adverse factors on the ciliary activity in the tubotympanum.     

Cytokine expression in experimental chronic otitis media with effusion in mice

OBJECTIVES: Although otitis media with effusion (OME) is still a common disease in children and adults, the pathogenesis is not yet fully understood. We studied the effects of intratympanic injection with endotoxin purified from nontypeable Haemophilus influenzae on the characteristics of middle ear effusion (MEE). METHODS: Murine model of OME was developed by eustachian tube (ET) blockage followed by intratympanic inoculation with endotoxin (endotoxin group) or saline (control group). The mice were decapitated and histological changes and the production of inflammatory cytokines in MEEs were examined 3 days, 2 weeks, and 2 months after injection. RESULTS: All mice showed OME until 2 months after ET blockage. Most MEEs in the control group were serous, and mucoid or pultaceous MEEs were found only in the endotoxin group. Subepithelial space of middle ear mucosa was severely thickened with the infiltration of a large number of mononuclear cells in the endotoxin group. The levels of tumor necrosis factor-alpha (TNF-alpha) in MEEs were significantly higher in the endotoxin group than in the control group at all time points. Further, in situ hybridization showed that TNF-alpha messenger RNA was expressed not only by leukocytes and macrophages in MEEs but mononuclear cells present in the subepithelial space of middle ear mucosa. CONCLUSIONS: These results indicate that ET blockage is essential for the induction of serous MEE and additional administration of endotoxin is associated with the production of mucoid MEE accompanied by histological changes with inflammatory cell infiltration and cytokine production in the tympanic cavity.     

Ciliary activity in the in vitro tubotympanum

Summary We have introduced a tissue culture technique in which the ciliary activity of the cultured tubotympanum can be studied. We have found that ciliated cells of the eustachian tube and middle ear lining continued a beating activity during 168 h of observation. The mean loss of activity of the ciliated cells from the eustachian tube or mucosal sites proximal to the tube was 20% or less, while that of mucosal sites distal to the tube was about 40% even after 168 h of cultivation in our culture medium of RPMI 1640. Our technique of tissue culture is available for studying the long-term effects of various therapeutic agents or adverse factors on the ciliary activity in the tubotympanum.     

鼓膜置管治疗鼻咽癌放疗后分泌性中耳炎疗效观察

目的:探讨鼓膜置管对鼻咽癌(NPC)放疗后的分泌性中耳炎(SOM)的疗效。方法:对32例(51耳) NPC放疗后经鼓膜切开抽液冲洗治疗无效的SOM患者进行鼓膜置管和随访,对治疗耳的咽鼓管功能、听力及其 他症状的改变进行评估。结果:随访6个月～5年,治愈8耳,治愈率为15.7%,有效41耳,总有效率为96.1%。 7耳(13.7%)咽鼓管功能好转,所有重复置管耳的耳功能均得到不同程度的改善。置管后耳漏发生率为25.5%, 鼓膜穿孔发生率为9.8%。结论:鼓膜置管治疗SOM有利于咽鼓管功能的恢复,对于咽鼓管功能已经严重损害 的患耳,重复鼓膜置管是维持耳功能的可靠手段;鼓膜置管的并发症利大于弊。