Masanori Shiwa

Expression and Localization of mRNA for Epidermal Growth Factor and Epidermal Growth Factor Receptor in Human Cholesteatoma

The roles of epidermal growth factor (EGF) and epidermal growth factor receptor (EGF-R) in the proliferation and progression of the epithelium of middle ear cholesteatoma were studied. An attempt was made to elucidate the site and degree of localization of the EGF mRNA and EGF-R mRNA in the epithelium of the cholesteatoma by means of the non-radioactive in situ hybridization method. Ten cholesteatoma specimens excised during operations and six normal skin specimens (control) collected from the external ear canal were used in this study. The signal of the EGF mRNA was slightly expressed in part of the basal cells in only one of the six control specimens, while the signal was strongly expressed along the basal cells of the cholesteatoma epithelium in five of the ten specimens. The signal of the EGF-R mRNA was observed along the basal cell layer in five of the six control specimens, while the signal was strongly expressed in all layers of the cholesteatoma epithelium in all ten specimens. The expression was especially marked in the basal cell layer. These findings suggest the possibilities that abnormal expression of the EGF-R mRNA in nearly entire epithelial layers of cholesteatoma is due to overexpression of EGF-R gene, and that there is a mechanism of epithelial basal cell proliferation through an autocrine regulatory system via EGF and EGF-R.

Molecular biological diagnosis of congenital and acquired cholesteatoma on the basis of differences in telomere length.

Objective To establish a molecular biological basis for differentiation of congenital and acquired cholesteatoma.

A Study on Epidermal Proliferation Ability in Cholesteatoma

With the objective of estimating proliferation ability of epidermis of middle ear cholesteatoma, the difference in proliferating cell nuclear antigen (PCNA) staining between the skin of the bone region of the external ear canal (control skin) and cholesteatoma epidermis and the effects on PCNA staining of subepidermal inflammatory cell infiltration of cholesteatoma were immunohistochemically studied using an antibody against PCNA. Transforming growth factor‐α (TGF‐α) is known to promote epidermal proliferation based on autocrine mechanism. But it is not clear that cholesteatoma epidermis is actually in the state of hyperproliferation under the effect of this growth factor. To estimate the effect of TGF‐α on epidermal proliferation ability, the authors compared the location of PCNA and TGF‐α in the same specimen. Unlike the control skin, not only epidermal basal cell layer and suprabasal cell layer, but also more superior layers were found to have high levels of PCNA staining in the epidermis of cholesteatoma. However, in the same cholesteatoma epidermal tissue, the PCNA staining was varied and the difference was ascribable to subepidermal cell inflammation. It appeared that the proliferation ability was high in regions where subepidermal inflammatory cell infiltration was severe. These differences in microenvironment are inferred to greatly affect proliferation ability of cholesteatoma epidermis.

Expression of transforming growth factor-α (TGF-α) in cholesteatoma

This study aims at elucidating the role of cytokines in the mechanism of proliferation of cholesteatoma epithelium by investigating the mode of expression of epidermal growth factors, such as TGF-alpha. The subjects of this study were patients who had undergone operation for middle ear cholesteatoma. Skins of the bone region of the external ear canal (normal skin) of the same patients were used as the negative control. The mode of expression of TGF-alpha was studied by immunohistochemistry and in situ hybridization. In the immunohistochemical study, there were no conspicuous differences observed between cholesteatoma tissues and normal skin. After in situ hybridization, expression of TGF-alpha mRNA was mainly observed in the epidermal basal cell layer in the normal skin, while in the cholesteatoma epidermis with severe inflammatory cell infiltration, expression of TGF-alpha mRNA was observed up to layers superior to the basal cell layer. The expression of TGF-alpha mRNA is greatly affected by subepithelial connective tissue, strongly suggesting involvement of paracrine regulation in proliferation of cholesteatoma epithelium.

Terminal Differentiation of Epithelial Cells in Middle Ear Cholesteatoma: Investigation of Patterns of Expression of Protein Kinase C-δ and Protein Kinase C-η

Objectives: The objective of this study was to elucidate the differentiation mechanism of keratinocytes in cholesteatoma.

The hearing status in 12 female and 15 male Japanese Fabry patients

OBJECTIVE Fabry disease (FD) is an x-linked inherited disease that causes a lack of a lysosomal enzyme, alpha-galactosidaseA, leading to cellular accumulation of glycosphingolipids of the whole body. This accumulation in the inner ear causes hearing loss also. However, FD is rare, and the frequency is lower in females than in males. Thus, there have been few comparative studies between women and men for hearing loss in FD. Accordingly, we examined the hearing status of both male and female FD patients and elucidated the similarities and differences. We also analyzed for correlations between the hearing status and renal and heart disorders. METHODS 12 women and 15 men were studied by means of pure tone audiometry, the relationships between the hearing status and the renal and cardiac functions. RESULTS The audiogram type was the flat type in a majority of both women and men, followed by the high type and low type, while the U-shaped type was rare. Examination of the thresholds average showed abnormality in one woman and four men. Comparison to threshold for each age bracket of normal subjects showed abnormality in three women and nine men. No correlations were found between the hearing loss and either the renal or cardiac function. All the patients with renal dysfunction had abnormal hearing. CONCLUSIONS The frequency of hearing loss in FD was higher in men than in women. Also, there may be some relationship between renal function and hearing loss in FD.