Healthy Middle Ear Research Articles

Keratinization of middle ear cholesteatomas

A histochemical study was performed to clarify further the role played by epidermal transglutaminase (ETgase) in the keratinization of aural cholesteatoma. Weakly and strongly keratinized epidermal tissues and healthy middle ear mucosa were included as references. A first assay revealed the distribution of non-specified acyl donor substrates. In a second assay, the topography of involucrin was assessed immunohistochemically. In both epidermal and cholesteatoma matrix tissues, the presence of acyl donors was not restricted to the sites of (E)Tgase activity, but was almost uniformly extended throughout living layers. In reference tissues, residual acyl donors were poorly detected in horny layers, while they were more abundant in the stratum corneum of the cholesteatomas studied. The presence of involucrin along the cell membrane was observed at varying distances throughout the spinous and granular layers, depending upon the epidermal and matrix configurations. In thick epithelia, involucrin rapidly became concentrated at the cell periphery (in spinous keratinocytes), while in thin epithelia it was usually associated with cell flattening. This latter staining profile was observed more frequently in cholesteatomatous tissues. In addition, we regularly noticed an immediately suprabasal accumulation of involucrin, suggesting a locally hyperproliferative state of the matrix. An insufficient availability of acyl donors, especially involucrin, could not be used to explain the defective ETgase-mediated cross-linking of cholesteatoma cell membranes during terminal stages of differentiation. The present investigation may be the first to demonstrate the presence of involucrin in middle ear mucosa.

Bioactive Glass‐Ceramics in Middle Ear Surgery An 8‐Year Reviewa

An 8-year follow-up of Ceravital middle ear prostheses showed there was extremely good tolerance in the middle ear space. Incompatibility phenomena were not observed, and inflammatory reactions were neither caused nor supported by the implants. The tympanoplasties were always performed without interposition of cartilage between the tympanic membrane or the tympanic membrane graft and the disk-shaped portion of the implant, and extrusions were never observed. Long-lasting inflammatory processes appeared to destroy implants the same way they destroy ossicles. Transient inflammatory periods (such as episodes of purulent otitis media, which occurred soon after the prostheses were implanted) did not lead to any remarkable changes of the surface of the implant. In healthy middle ears, the hearing results were stable.

An overlooked site of tissue mast cells--the human tympanic membrane. Implications for middle ear affections.

The tympanic membranes of 14 deceased, with no record of ear disease in their medical files, were investigated with respect to the presence of mast cells. The Shrapnell membrane (pars flaccida) had a rich content of mast cells, whereas the pars tensa had none except for a few located close to blood vessels along the handle of the malleus. The volume density of the pars flaccida mast cells was calculated as 3.9% and the number of mast cells/mm2 as 299 +/- 35 (mean +/- SE; n = 14). The possible role of these mast cells under both healthy and diseased middle ear conditions is discussed.

A tympanometric pressure swallow test for assessment of eustachian tube function.

Normal Eustachian tube function is necessary for maintaining healthy middle ear conditions. A tympanometric pressure swallow test is proposed which can be used to assess Eustachian tube function behind an intact tympanic membrane. In general, after recording a baseline tympanogram, mechanically created positive and negative air pressures are created in a hermetically sealed ear canal causing increased pressure on the middle ear air cushion. The patient is then asked to swallow. Preliminary clinical findings in ears with apparent normal Eustachian tube function show that a shift in the peak pressure point of the tympanogram occurs when the tympanogram is recorded again, implying that the Eustachian tube opens and equalizes middle ear air pressure. Positive canal pressure swallow maneuvers show a peak pressure shift to a negative value, whereas negative pressure swallow maneuvers show a peak pressure shift to a positive value.

Tympanoplasty today. Large and small cavities, closed eustachian tube, combined skin grafts.

Ten years have passed since tympanoplasty became known. Looking back, we can state that the theory of the audiological principles has proved to be right. And we must add, the surgical results very frequently, as far as this is possible, have met the theoretical requirements. The<i>mean result</i>, naturally, is less than the theoretical one because it is difficult to restore the ideal status of the middle-ear tissue, a point which would be essential for a normal threshold of hearing. In this paper I would like to discuss a few problems concerning the surgical procedure. When performing a tympanoplasty we wish to reestablish (1) a completely healthy middle ear; (2) the functional reconstruction of the tympanum; and (3) a definitely dry external auditory canal or cavity, respectively. To be as careful as possible with the function structures—epitympanum and ossicular chain—and also not to form a large mastoid cavity instead of

EXPERIMENTAL STUDIES ON ALLERGIC OTITIS MEDIA

Experimental acute otitis media was produced by injecting various agents into the middle ear cavity of the guinea-pig and the animal was sacrificed for histological studies after 7 days of careful observation. The results are summarized as follows: 1) The introduction of bacteria suspension, egg albumin or milk into the healthy middle ear cavity produced the proliferation of the connective tissue and the infiltation of neutrophilic leucocytes in the mucosa, The secretion in the middle ear mostly consisted of the neutrophilic leucocytes. The introduction of egg albumin and milk produced a milder inflammation as compared with that of bacteria. No eosinophilic leucocytes were found in the lesion of these series. 2) In the guinea-pigs sensitized with egg albumin or milk, the introduction of the antigen agents into the middle ear cavity led to the allergic changes characterized by the edema, hemornhage, vascular dilatation, production of fibrin and the infiltration of eosinophilic leuco-cytes in the tympanic membrane or mucosa of fhe tympanic cavity. The secretion was also characterized by fibrin clots, blood, and eosinophilic cells. 3) When the egg albumin was employed as the antigen, the pathologic process was chara-cterized by high degree of edema, while with milk it is characterized by hemorrhage and fibrinous exudation. It is evident that different antigen gives rise to different histopathologic manifestations. 4) The injection of bacteria suspension into the tympanic cavity of the sensitized guinea-pig resulted in the edema, vascular dilatation, eosinophilic infiltration and hemorrhage, which are similar to the allergic response of the tympanic membrane or the mucosa of the cavity. However, these changes are much milder as compared with those produced by true antigen-antibody reaction. The edema, in some instances, was absent. Neutrophilic leucocytes are the chief constituent of the middle ear secretion, but in many instances, fibrin clots and eosinophilic cells were demonstrated. It is clear that the sensitized mucous membrane differs entirely in the reaction to bacteria from the intact membrane. 5) In non-allergic reaction, eosinophilic cells are scarcely detected in the tissue or secretion, but in allergic response, eosinophilic leucocytes are demonstrable in all instances. It is, therfore, considered that the presence of eosinophilic cells in case of acute otitis media is characteristic to the allergic nature of the inflammation.