Development Of Middle Ear Research Articles

Plasmin and Fibronectin Degradation in Chronic Secretory Otitis Media

Mucoid effusions from 39 children with secretory otitis media, altogether 42 specimens, were analyzed for proteolytic activity using radial caseinolysis procedures, for fibronectin using a solid-phase enzyme immunoassay, and for fibronectin fragmentation using immunoblotting. All samples contained proteolytic activity, tentatively identified as plasmin on the basis of comigration with purified human plasmin in zymographic analysis. In 19 specimens the plasmin level exceeded 1 microgram/mg of protein; the highest value recorded was 18.7 micrograms/mg. Low levels of net plasminogen activator activity were found in 12 specimens and identified as urokinase according to comigration with the urokinase standard in zymography. Fibronectin was detected in all but one of the 42 specimens; in seven specimens the levels exceeded those in normal plasma, calculated per milligram of total protein. Extensive fragmentation of fibronectin was found in 19 specimens, correlating with high plasmin levels. The results are indicative of an ongoing proteolytic process in secretory otitis media and suggest that plasmin-caused degradation of the fibronectin-containing basement membrane and subsequent formation of granulation tissue may be involved in the development of adhesive middle ears.

Major congenital ear malformations: surgical management and results.

Fifteen patients with major congenital aural atresia underwent operations using an anterior (trans-atretic bone) approach. Facial nerve monitoring was used in all cases and there were no instances of facial nerve injury. Postoperatively, two thirds of the patients had speech reception thresholds of 30 dB or better; the air conduction threshold (averaged for 500, 1,000, and 2,000 Hz) improved at least 25 dB in 80% of the patients and at least 30 dB in 60% of the patients (follow-up, 10 to 29 months). Minor revision surgery was necessary in three patients. On the basis of this series, several conclusions were made. First, one of the most important factors in proper patient selection is the degree of middle ear development on computed tomography, both in terms of size and ossicular formation. Second, every attempt should be made to keep the ossicular chain intact (versus use of a prosthesis), as this appears to optimize hearing results. Third, embryologic considerations and surgical experience predict a mobile stapes in the majority of major atresias. Lastly, facial nerve abnormalities are to be expected, especially in patients with significant microtia, but facial nerve monitoring will help minimize the risk of facial nerve injury.

The use of a SQUID magnetometer in the study and development of normal and artificial middle ear.

(1986). The Use of a SQUID Magnetometer in the Study and Development of Normal and Artificial Middle Ear. Acta Oto-Laryngologica: Vol. 102, No. sup432, pp. 11-14.

Otitis Media with Effusion During the First Three Years of Life and Development of Speech and Language

To determine the association between time spent with middle ear effusion and development of speech and language, 205 three-year-old children were studied. Each child had been followed prospectively from birth to record the number of episodes of middle ear disease and to document time spent with middle ear effusion. Standardized tests of speech and language were administered at age 3 years to children who had spent much time with middle ear effusion and to children who had spent little or no time with middle ear effusion. Children who had spent prolonged periods of time with middle ear effusion had significantly lower scores when compared with those who had spent little time with middle ear disease. The correlation was strongest in children from higher socioeconomic strata. Time spent with middle ear effusion in the first 6 to 12 months of life was most strongly associated with poor scores.

Evolution of the tetrapod ear: an analysis and reinterpretation

The dominant view of tetrapod otic evolution–the “standard view”–holds that the tympanum developed very early in tetrapod history and is homologous in all tetrapods and that the opercular process of the rhipidistian hyomandibula is homologous to the tympanic process of the stapes in lower tetrapods. Under that view, the labyrinthodont amphibians of the Paleozoic are usually considered ancestral to reptiles, and thus the “otic notch” of labyrinthodonts and the tympanum it presumably contained form the starting-point for middle ear evolution in reptiles. Four problems have classically been identified with the standard view: the differing relationships of the internal mandibular branch of N. VII (chorda tympani) to the processes of the stapes in amniotes and anurans; the differing orientations of the stapes in key fossil and living groups; the location of the tympanum in early fossil reptiles; and the transferral of the tympanum, during the origin of mammals, from the stapes to the articular bone of the lower jaw. An examination of these problems and of the solutions proposed under the standard view reveals the ad hoc, and therefore unsatisfactory, nature of the proposed solutions. To organize and review alternative hypotheses of otic evolution an analytical table is constructed, using three characters (tympanic process, Nerve VII, tympanum), each with two possible states. A total of eight hypotheses about middle ear evolution are possible under this system, one of which is the standard view. The seven “non-standard” hypotheses, only five of which have been argued in the literature, are briefly examined. Six of the “non-standard” hypotheses appear unattractive for various reasons, including reliance on ad hoc arguments. The seventh was first proposed by Gaupp in 1898. It is today almost universally ignored but apparently largely for historical rather than scientific reasons. This hypothesis, her called the “alternative view”, appears to rest on assumptions equally as plausible as those of the standard view. Moreover, it offers a solution of the problems associated with the standard view without, apparently, raising any similarly serious problems. This paper compares the standard and alternative views of middle ear evolution in detail. Comparison proceeds on two levels. On one level, they are compared in terms of the hypotheses of phyletic tetrapod relationships each promotes and how strongly each supports its hypothesis. Both views promote the same hypothesis of tetrapod relationships. The alternative view is the more parsimonious, but the difference is not considered sufficient to provide a choice. On another level, the two views are compared in terms of their implications for: (1) the evolution of relative and absolute auditory perceptive ability; (2) the origin of reptiles; (3) the evolution of the suspensorium and cranial kinesis; and (4) the origin and evolution of recent amphibians. The nature of the data required for a test of the implications of the two views is specified in each case. Where data are available. the alternative view is consistent and the standard view is inconsistent with these data. We conclude that the alternative view is the preferable hypothesis of middle-ear evolution. This conclusion implies the following: the tympanic membranes and the tympanic processes of the stapes in recent mammals, reptiles + birds. and frogs. are not homologous; the evolution of “special periotic systems” in the ancestors of amphibians and amniotes were independent events and preceded the evolution of tympanic membranes; the amphibian tympanic membrane. probably including that of labyrinthodonts. is not ancestral to that of amniotes. and that labyiinthodonts with an otic notch are not suitable as amniote ancestors; the stapes of early reptiles functioned primarily as part of the jaw suspension rather than in hearing; the mechanisms and abilities of sound perception in recent tetrapods are likely to be diverse rather than forming parts of a cline; and the lack of a tympanum in Gymnophiona and Caudata may be a retention of a primitive condition.

Lymphocyte Subpopulations in Otitis Media with Effusion

Summary: The distribution of B and T lymphocytes and macrophages in the middle ear fluid (MEF) was studied in groups of children with otitis media associated with serous, seromucinous, or mucoid effusions in the middle ear. The subpopulations of T and B lymphocytes and macrophages were identified in the MEF by employing the techniques of spontaneous erythrocyte rosetting (E), membrane immunofluorescence, erythrocyte-amboceptor-complement (EAC) and erythrocyte-amboceptor (EA) rosette formation, respectively. A significant number of B and T lymphocytes or macrophages were detected in all specimens; however, certain differences were observed in their relative distribution in different types of effusions. Serous MEF was characterized by a cellular response associated predominantly with macrophages, although T lymphocytes were also seen frequently. No B lymphocytes were seen in such exudates. The seromucinous MEF contained B and T lymphocytes and macrophages in approximately similar proportions. Significantly, however, the mucoid effusion consisted mainly of B lymphocytes. Only macrophages and no T cells were observed in these effusions. The cytologic findings reported here may be helpful in a more definitive classification of middle ear effusions. These data may suggest a possible role of the different components of cellular immunity in the development of middle ear effusions.Speculation: E rosette-forming cells predominate in the serous and seromucinous effusions of otitis media. EAC rosette-forming cells appeared as a predominant cell type in mucoid effusions. The different types of effusions in otitis media may represent the various stages of the same inflammatory process. The differences in the types of immunocompetent cells observed may reflect the nature of the underlying immune response in serous, seromucinous, or mucoid forms of otitis media.

A histological study of the development of the avian middle ear and tympanum.

The development of the middle ear and tympanum of Gallus gallus has been studied in embryos Hamilton-Hamburger stages 20-46. Particular attention was paid to the pattern of expansion of the pharyngeal pouch forming the tympanic cavity, and the histogenesis of the tissues of the region of the vestibular window. It is concluded that pouch expansion is brought about by simple epithelial growth into regions devoid of mesenchyme. The mesenchyme does not show significant cell death, but differentiates as connective tissue, macrophages, and sinus vascular spaces. The epithelium of the mature cavity is of endodermal origin, and there is no indication of celomic contributions. We provide a detailed morphological analysis of the development of the footplate from cells of both the second visceral arch and the otic capsule. These detailed observations on the patterns of chondrification of columella and capsular tissues permit the presentation of a model for cellular interactions leading to the differentiation of the annular ligament.

The pneumatization of the tympanum and the relationship to the facial canal

In development of middle ear, the pneumatization of the mastoid cellulae is well known.While the pneumatization of the tympanum is rarely discussed, tympanum itself has to pneum- atize. The author studied the relationship between the pneumatization of the temporal bone and thal of the tympanum, in vertical parallel section to pyramis in 50 cars of 50 cases.Dimensions of the tympanum was measured by the planimeter, and compared with the rate of the radiographical pneumatization of the temporal bone.Furthermore, the author observed the influence of the pneumatization of the tympanum to the facial canal wall. The results are as follows:1) High correlation between dimensions of the tympanum and pneumatization of the temporal bone was seen.Namely, the better the pneumatization of the temporal bones, the wider their dimensions, howe- ver the degree of repression, did not show more narpowing.2) The development of tympanal cellulae had a high correlation with the radiographical appearance of the temporal bone.3) Themore developed the tympanum, the thinner was the facial canal wall.This consequence is due to the absorbtion of bony tissue in pneumatization mechanism.In 24 cases out of 41, the facial canal wall defect was recognized in the portion of sinus tympani.From the result of(3), the cause of the facial paresis in tympanoplastic procedure was discussed.The author notes that when the tympanoplasty is employed in caseof a well developed pneumatization of the temporal bone extreme care must be taken.