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Background and Objective: The 4-META/MMA-TBB [4-(2-methacryloxyethyl)trimellitic anhydride/methyl methacrylate-tributylborane] resin is widely used as a dental adhesive. It has also been applied in the dressing of gingival wound surfaces following periodontal surgery. However, its effect on the regeneration and/or cell attachment of the oral epithelium remains to be clarified. To evaluate the effect of the resin applied as a wound dressing, we investigated expression of laminin 5, integrin β4 and cytokeratin 14 in regenerating oral epithelium treated with this resin following gingivectomy from the viewpoint of cell attachment and differentiation. Material and Methods: The resin was applied to the entire wound surface in rats after gingival surgery, and regenerating epithelium was examined immediately and at 1, 3, 5, 7 and 14 days later. The resin was removed 2 weeks after application in some animals and tissue further examined at 1, 3, 5 and 7 days later. Results: Regenerating epithelium under the resin was not keratinized, but became keratinized immediately after removal of the resin. Laminin 5 and integrin β4 were immunolocalized in the basal lamina, the internal basal lamina, in marginal cells of the regenerating epithelium and at the resin–regenerating epithelium interface. Cytokeratin 14 localized in the regenerating epithelium underneath the resin, as well as in healthy and regenerated junctional epithelial cells. Conclusion: These results suggest that this resin covers the wound surface and that the regenerating epithelium biologically adheres to the resin during the initial process of its regeneration. [ABSTRACT FROM AUTHOR]

This review describes culture techniques for the epithelial system as well as trends in the clinical application of cultured keratinocytes in our department and the possibility of applying the techniques to other organs. Cultured epithelium and cultured dermis in particular have considerably preceded regeneration of other organs in the field of regenerative medicine. Since 1988 we have grafted cultured keratinocytes by the Rheinwald-Green modified method in at least 500 patients with large skin defects. As a result of the establishment of a culture technique for individual patients, it is now possible to prepare enough regenerated epithelium to cover the body surface area of as many as 10 adult patients in approximately three weeks after collecting 1 cm2 of skin, and then remaining cultured keratinocytes can be cryo-preserved for two-stage dermatoplasty at another site. This procedure makes it possible to avoid frequent skin collection from the same patient and thereby improves patients’ quality of life and activities of daily living. On the other hand, to solve the problem of regenerated epithelium shrinking and problems with graft efficiency on dermis defect lesion, we have developed a proteinase-resistant regenerated dermis by mixing a certain protein with a fibrin scaffold. Recently we also took the initiative in grafting hybrid-type regenerated trachea in an animal experiment by using the epithelial and dermal cell culture technique, and some results of the graft were obtained. [ABSTRACT FROM AUTHOR]

Using suppressive subtractive hybridization, we have identified a novel gene, which we named early epithelial differentiation associated (EEDA), which is uniquely associated with an early stage of stratified epithelial differentiation. In epidermis, esophageal epithelium, and tongue epithelium, EEDA mRNA, and antigen was abundant in suprabasal cells, but was barely detectable in more differentiated cells. Consistent with the limbal location of corneal epithelial stem cells, EEDA was expressed in basal corneal epithelial cells that are out of the stem cell compartment, as well as the suprabasal corneal epithelial cells. The strongest EEDA expression occurred in suprabasal precortical cells of mouse, bovine, and human anagen follicles. Developmental studies showed that the appearance of EEDA in embryonic mouse epidermis (E 15.5) coincided with morphological keratinization. Interestingly, EEDA expression is turned off when epithelia were perturbed by wounding and by cultivation under both low and high Ca2+ conditions. Our results indicate that EEDA is involved in the early stages of normal epithelial differentiation, and that EEDA is important for the “normal” differentiation pathway in a wide range of stratified epithelia. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The article focuses on melanocytic nevi. The term nevus can be used to imply - congenital or acquired lesions consisting of pigmented or nonpigmented melanocytes, with or without participation by nerve elements. Congenital malformations formed by excessive vascular, fibrous, epithelial or any other tissue of skin. The article confines itself to the latter view. In normal skin, melanocytes are present as isolated cells in the basal layer of epidermis. They are derived from neural crest. The ratio of basal keratinocyte to melanocyte varies.

A study of cutaneous melanocytes and dermal changes around non-melanoma lesions and malignant melanomas in Queensland patients has been undertaken. The findings from the non-melanoma group are reported in this paper. The aim of the study was to see if a melanoma affected the melanocytes in the surrounding epidermis. To do this, a base-line for changes in the melanocytes in Queensland patients with non-melanoma tumours was sought. The features studied were : number, morphology and activity of melanocytes, epidermal pigmentation and solar-induced dermal changes. [ABSTRACT FROM AUTHOR]

This article focuses on mechanobullous diseases, traditionally called epidermolysis bullosa (EB). Early in this century, the classification of EB subtypes was based on their clinical features and mode of inheritance, since light microscopy could not disclose the hallmarks clearly enough for any specific typing of these noninflammatory diseases. The wide use of the electron microscope in the 1970s, nevertheless, opened up fresh opportunities for the new typing, which came into existence because of the practical need for a systematic ordering of a number of these diseases. The etiologic pathogenesis of the EB subtypes is not well known, and the challenge of the future is solving these problems on the biochemical level. A significant step forward has been the clarification of the complicated network of the hemidesmosomes and the fibers that bind epidermis and dermis.'' Tonofilaments, the intercellular filaments of basal keratinocytes, converge into attachment plaques that are visible thickenings of the basal cell plasma membranes.

Morphological studies performed with the light microscope determined that keratohyalin is limited to a particular layer of the epidermis, the stratum granulosum. The most important objective in understanding the biochemistry of keratohyalin would be to isolate it and subject it to direct chemical analysis. Although most species human, bovine have keratohyalin granules are limited to the cytoplasm, certain species have intranuclear deposits which are electron dense and may represent intranuclear keratohyalin. Keratohyalin granules seem to gradually lose their identity as the stratum granulosum blends into the stratum corneum.

Based on the evidence produced in this investigation it is apparent that what has been termed "Epithelial Rests of Malassez" are groups of epithelial cells surrounded by an outer argyrophilic limiting membrane. Further it is evident that the cells bear a strong resemblance to the epithelial cells seen in the basal layers of epidermis and the oral mucous membranes and have little or nothing in common with secretory cells. Based on the ultrastructural morphology and histochemical evidence, "resting epithelial cells" seem to be an appropriate description of these cell groups. Presumably, however, the cells contain all the necessary components to meet whatever functional demands may be placed upon them through environmental alterations. [ABSTRACT FROM AUTHOR]

Epithelia are found at the interfaces between body compartments where they act as selective permeability barriers that maintain the unique composition of the compartments on either side. Epithelial barrier function is dependent on tight junctions (TJs), which seal the intercellular or paracellular spaces but may permit selective permeability. In simple epithelia (one cell thick), the function of TJs is relatively well understood. By contrast, our understanding of TJ structure and function in stratified epithelia (e.g. the epidermis) is limited. This article briefly discusses what is known about TJs and their components in simple epithelia and speculates about their roles in the epidermis. [ABSTRACT FROM AUTHOR]

In recent years, cutaneous epithelial stem cells have attained a genuine celebrity status. They are considered the key resource for epidermal and skin appendage regeneration, and are proposed as a preferential target of cutaneous gene therapy. Follicular epithelial stem cells may also give rise to a large variety of epithelial tumors, and cutaneous epithelial stem cells likely are crucial targets for physical or chemical agents (including carcinogens) that damage the skin and its appendages. However, as this Controversies feature illustrates, few experts can agree on how exactly to define and identify these elusive cells, or on where precisely in the skin they are localized. Given their potential importance in skin biology, pathology and future dermatological therapy, it is, therefore, timely to carefully reconsider the basic questions: What exactly is a stem cell, and how can we reliably identify epithelial stem cells? How many different kinds are there, and how do they differ functionally? Where exactly in the skin epithelium is each of the putative stem cell subpopulations located, and can we selectively manipulate any of them? [ABSTRACT FROM AUTHOR]

An unusual case of ameloblastoma which depicts cystic follicles containing orthokeratin, parakeratin, desquamated epithelium and necrotic material with dystrophic calcification is presented. The presence of ameloblast-like cells confirms the diagnosis of an ameloblastoma. However, certain features resembled those of the keratoameloblastoma and others, less convincively, the papilliferous keratoameloblastoma. The extensive keratinisation in this tumour and in the aforementioned neoplasms raises the question whether they represent variants of the acanthomatous ameloblastoma. [ABSTRACT FROM AUTHOR]