The present study was concerned with oral reparative and inflammatory reactions, benign epithelial proliferations and malignant lesions including their prestages. Following investigations of normal oral mucosa, biopsy and surgical specimens of diseased human oral mucosa were studied with light and electron microscopical methods. In addition, experimental models of oral wound healing and carcinogenesis were developed. Combining morphological (immunofluorescence, immunocytochemistry, electron microscopy) and biochemical (SDS polyacrylamide gel electrophoresis) techniques differentiation and function of epithelial and non-epithelial cells of the oral mucosa were investigated. Clinical pathology. 725 oral lesions were collected from the files of the Dermatological Clinic of the University of Hamburg. Among these lesions epithelial hyperplasias and neoplasias represented the most frequent alterations of the oral mucosa. The incidence of premalignant lesions (3.7%) was consistent with the percentages reported in the literature. On frozen or glutaraldehyde-fixed tissue samples the value of immunohistological and ultrastructural methods was examined with particular respect to the distinction of reactive inflammatory processes from true premalignant and malignant lesions and with special reference to the differential diagnosis of epithelial and non-epithelial tumours. Examples were given for immunological characterization of inflammatory lesions and for histogenetical typing of neoplasias. Normal oral mucosa. Biochemical and morphological investigations of keratin filaments showed that basal and suprabasal epithelia contain different keratin polypeptides related to the degree of cell differentiation. These cytoskeletal modifications were seen to be associated with cell membrane differentiations which was demonstrated by different lectin affinities to basal and suprabasal compartments of epithelium. At the epithelial-mesenchymal interfaces macromolecular substances appeared (e.g. fibronectin) which are produced by basal epithelia (e.g. laminin) and connective tissue cells leading to the formation of the basement membrane zone. Immune competent cells were seen to be regular components of normal oral mucosa. Within the epithelium Langerhans cells and T lymphocytes of the suppressor/cytotoxic phenotype were shown to be the predominant inflammatory cells. B lymphocytes, T lymphocytes of the suppressor/cytotoxic and helper/inducer phenotypes and typical macrophages represented cellular elements of the connective tissue. All these non-epithelial cells were found to contain vimentin filaments.(ABSTRACT TRUNCATED AT 400 WORDS)
