Biomedical subjects
Publications and source records attributed to A W Barrett.
Adenomatoid hyperplasia of palatal minor mucous glands is rare but significant because the clinical appearance mimics malignant disease. The typical history of a painless, indolent palatal swelling, together with the histological picture of benign glandular hyperplasia and hypertrophy, are illustrated in this report.
Langerhans' cells (LC) are dendritic, antigen-presenting cells present within the epithelium of skin and mucosa, including that of the oral cavity. This article reviews the literature on the phenotypic and functional features of oral mucosal Langerhans' cells, and speculates on other aspects by extrapolating from data on their epidermal counterparts.
Nine cases of primary oral mucosal melanoma in Caucasian patients were reviewed and the tumours analysed for expression of S100, HMB45, NKI/C3, HLA-DR, PCNA, cytokeratin and von Willebrand factor. The clinical, histopathological and immunohistochemical features were quite distinctive and our findings support previous suggestions that oral melanoma should be classified as a separate entity rather than as a sub-type of cutaneous melanoma.
Adenomatoid hyperplasia is a rare cause of swelling of the oral minor salivary glands, but is of significance because of its clinical resemblance to salivary gland tumors. The histologic appearance is one of benign hyperplasia and hypertrophy of the minor mucous glands. The clinical and histologic features of 20 new cases are reported, 19 of which occurred in the hard or soft palate. The cause of adenomatoid hyperplasia has hitherto been unclear, but the observation that 14 subjects were tobacco smokers or denture wearers, or both, suggests chronic, local trauma may be an important factor in the development of the condition.
Suspensions of human oral epithelial cells were stained with antibodies to CD1a and HLADR conjugated with fluorochromes and analysed by flow cytometry with the aim of purifying double-labelled Langerhans cells, a population comprising approximately 2% of the cell total. Whole suspensions had high levels of autofluorescence and a wide range of forward and right angle scatter properties. The mean percentage of CD1a/HLADR+ cells was 2.1%, though the double-labelled cells did not form a discrete group and the percentages of positive cells using control antibodies were similar. Density gradient centrifugation prior to flow cytometry did not facilitate Langerhans cell identification within the suspension. The results indicate flow cytometric analysis of minority cell populations (such as Langerhans cells) within oral epithelium is limited by the autofluorescence of physically heterogeneous keratinocytes, and emphasize the importance of controls in studies of oral epithelium which use this method.
An immunoperoxidase technique was used to compare wax-embedded tissue with frozen tissue for quantitative immunohistochemistry of oral mucosal Langerhans cells. Initial experiments using anti-CD1a, -HLADR and -S100 antisera showed that phenotype, fixative, antibody dilution and trypsinisation of the tissue section significantly affected Langerhans cell counts. Only the anti-HLADR antibody detected Langerhans cells in both frozen and wax-embedded sections. Some 38% of S100-positive dendritic cells were situated in the stratum basale, and 41-84% of these contained melanin as determined by double-labelling. Sections from 39 volunteers were then reacted with the anti-CD1a and -HLADR antibodies. The morphology of Langerhans cells was more dendritic in frozen sections, and the mean HLADR-positive Langerhans cells count in frozen sections was significantly higher than that in wax-embedded sections from the same individual. The intra-individual ratio of counts between frozen and wax-embedded sections was variable; hence, the apparent loss of HLADR antigenicity as a result of tissue processing was unpredictable. Counts of CD1a-positive Langerhans cells were consistently higher. We conclude that the use of anti-CD1a antibody on frozen tissue is the optimum method for quantitative studies of oral mucosal Langerhans cells, and that such studies performed on wax-embedded tissue may be unreliable.
External beam radiotherapy treatment of malignant conditions in the head and neck can give rise to several adverse oral effects if the oral or salivary tissues are within the field of beam. We report on a patient with widespread oral melanotic hyperpigmentation that developed after a course of radiotherapy for metastatic carcinoma in the cervical lymph nodes. As no other local or systemic cause was evident it is possible this abnormal hyperpigmentation was a result of the radiotherapy. The development of oral melanotic macules as a consequence of radiotherapy has not been previously described.
This report describes a case of oncocytoma, a rare, benign tumour which is particularly uncommon in the submandibular gland. The neoplasm was a chance finding in a gland which presented with recurrent swelling, assumed to be due to chronic sialadenitis.
The demonstration of S100 protein is used extensively for both research and diagnostic purposes in oral biology and pathology. This article reviews the structure and putative function of S100, technicalities of S100 immunohistochemistry, the cells of the oral and perioral tissues which express S100 and the possible significance of S100 expression in disease.
Despite the complex role of melanocytes in skin physiology, the function of oral mucosal melanocytes has attracted little research interest and remains largely unclear. This article reviews what is known about oral mucosal melanocytes and identifies areas of research that may shed further light on their role in oral biology.
Temporomandibular joint osteoarthrosis is common but typically asymptomatic. This article describes a patient with symptomatic left temporomandibular joint osteoarthrosis in whom pain in the right side of the tongue and ear, and dysphagia, subsequently developed simulating Eagle's syndrome. The concept of Eagle's syndrome is reviewed.
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A patient with de Lange syndrome who also had a variant of von Willebrand's disease is reported. The problems with dental surgery, particularly with respect to difficulty of extraction and bleeding tendency, are discussed.
Oral mucosal Langerhans cells (OMLC) may have an important role in the induction of immune responses to oral pathogens. In this study, anti-HLA-DR antibody-coated immunomagnetic beads were used to purify OMLC from suspensions of normal human buccal epithelium and the capacity of the purified cells to function as accessory cells (AC) was investigated. Electron microscopy was used to show that the purified cells possessed all recognized ultrastructural features previously described in epidermal Langerhans cells. Using T lymphocyte proliferation assays in hanging drop microcultures, it was found that purified OMLC could function as AC for responses to concanavalin A by autologous T cells. Purification of OMLC from small biopsies of oral mucosa has enabled us to show that OMLC, like epidermal Langerhans cells, can function as AC in vitro.
Erythema multiforme is a vesiculobullous condition that may affect skin and/or mucosa. Oral lesions are characterized by hemorrhagic crusting of the lips and ulceration mainly of the non-keratinized mucosa. This paper describes a patient who presented with gingival lesions as well as the more typical oral signs of erythema multiforme.
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Oral mucosa from six sites in 95 autopsies was tested for melanin using the Masson-Fontana silver reduction method. Melanin was detected in 51.6% of labial, 46.3% of palatal, 45.3% of buccal, 28.4% of mandibular gingival, 25.3% of lingual and 21.1% of maxillary gingival samples. 93.7% of epidermal samples from the same population were positive. In 24.2% of the subjects there was no detectable melanin at any intraoral site and 4.2% showed activity in all six sites. The mean number of positive oral sites per individual was 2.2. There are thus regional differences in oral epithelial melanocyte activity, but no parallel with the known regional incidence of primary oral melanoma.
Tobacco and alcohol consumption are known predisposing factors to the development of oral cancer, though the mechanism by which they act is unclear. The density of Langerhans cells (LC) has been shown to decrease in the uterine cervix of smokers, possibly indicating reduced immune surveillance and increased risk of malignant change. This study examined biopsies of normal human lateral border of tongue taken from 41 necropsies whose histories of tobacco and alcohol consumption were known. LC were identified in fixed, wax-embedded sections using a monoclonal antibody to HLADR and an immunoperoxidase technique. The mean density of LC in smokers of the equivalent of 11 or more cigarettes daily was significantly higher than moderate and non-smokers when counts were expressed per mm epithelial surface and basement membrane length. There were no significant differences in LC numbers in relation to alcohol consumption, age or sex, but there was a significant interaction between tobacco and alcohol. The results suggest that either human oral LC respond to external toxins, or that physical changes in the epithelial barrier induced by such toxins necessitate the presence of more LC to maintain the integrity of the epithelium.