The structure of bovine periodontal ligament with special reference to the epithelial cell rests

The aim of this study was to determine the structure of the bovine periodontal ligament, with special reference to epithelial cell rests (ECR) and their cytokeratin content. Periodontal ligament was obtained from bovine molar teeth and studied at both the light microscopic and electron microscopic levels. Cytokeratin content was determined using immunohistochemistry against a number of cytokeratin antibodies and specificity tested against bovine and human oral mucosa. Collagen fibril diameters and the area of a fiber bundle occupied by collagen were determined using a digital planimeter with a digitizing tablet. The majority of periodontal fibroblasts possessed considerable quantities of roughened endoplasmic reticulum, indicating rapid synthesis and secretion of collagen, but no intracellular collagen profiles were present. Endothelial cells showed Weibel-Palade bodies. Collagen fibril diameters showed a unimodal distribution with a mean collagen fibril diameter of 55.3 nm. The mean percentage area of the extracellular matrix occupied by collagen was 42%. Structurally, ECR were unusual in exhibiting large numbers of microvilli and conspicuous amounts of cytokeratin filaments. Bovine ECR showed a positive reaction to the pancytokeratin MNF116 (which reacts with the cytokeratins 5, 6, 8, 17, and probably 19), to PCK-26 (which reacts with the type II cytokeratins 1, 5, 6, and 8) and to cytokeratin 13. There was no reaction for cytokeratins 1, 4, 10, 11 and 18. Structurally, bovine periodontal ligament showed features common to other species. However, ECR in terms of both structure and cytokeratin content showed features indicative of important species differences which may have relevance when considering the etiology of radicular cysts.

Bilateral internal mammary artery atherosclerosis: a late complication of delayed repair of coarctation of the aorta

A 58-year old patient who had undergone repair of aortic coarctation at 19 years of age, subsequently developed coronary artery disease requiring coronary artery bypass surgery. At operation both internal mammary arteries were found to be totally occluded with calcific atherosclerosis. We therefore advise that the internal mammary arteries should be assessed carefully in patients with similar past histories.

Hybrid central giant cell granuloma and central odontogenic fibroma-like lesions of the jaws

Ten lesions from eight cases are presented of a rare intra-osseous jaw lesion with the combined histological features of giant cell granuloma and central odontogenic fibroma. Lesions arose over a wide age range and presented as monolocular or multilocular radiolucencies with cortical expansion and, in one case, perforation. Two lesions recurred after curettage, one being eradicated by a second curettage and one by conservative excision. Histologically, zones of typical giant cell granuloma lay in a fibrous stroma containing islands, strands and clusters of epithelial cells. Islands often contained duct-like spaces or hyaline basement membrane globules. Trabeculae of osteoid were present in five lesions. Recurrent lesions showed features identical to the initial lesion, including recurrence of the prominent epithelial component. These features cannot be conclusively ascribed to a variant of either giant cell granuloma, central odontogenic fibroma or aneurysmal bone cyst, but the clinical features are slightly more suggestive of giant cell granuloma. Attention is drawn to the characteristic and potentially confusing histological appearances. The presence of giant cell granuloma-like areas in central odontogenic fibroma-like lesions is associated with an increased risk of recurrence following curettage.

The immunohistochemical identification of human oral mucosal melanocytes

With the aim of identifying melanocytes, 60 samples of wax-embedded palatal and buccal mucosa front 30 autopsies were analysed for expression of S100, HMB-45 and NKI/C3 in combination with a Masson Fontana stain. The counts of positive cells were compared with those derived from 3,4 dihydroxyphenylalanine (DOPA) staining in fresh samples of gingiva. Polyclonal antisera to S100 stained dendritic cells throughout the epithelium, but monoclonal antibodies to S100, HMB-45 and NKI/C3 labelled cells that were restricted to the basal layer, often in clusters with some sections negative. The mean counts of positive basal dendritic cells per millimetre basement-membrane length were 4.3 (polyclonal S100+. range 0-19). 0.8 (monoclonal S100+. range 0-7.3), 2.0 (HMB-45, range 0-17.8) and 0.9 (NKI/C3, range 0-14.9). Of the last three, HMB-45 produced the clearest and most specific staining. Counts of basal dendritic cells were significantly higher (p < 0.0005) with polyclonal antisera to S100 than with all other markers except DOPA but HLA-DR staining showed that Langerhans cells may also be located in the basal layer. The highest values were always in buccal mucosa, but statistically significantly so (p < 0.0005) only with polyclonal anti-S100. Basally located DOPA+ cells had a mean density of 4.6 per millimetre basement-membrane length, but in five cases DOPA also labelled suprabasal dendritic cells, presumably Langerhans cells. The mean basal DOPA+ values were significantly higher than those with monoclonal antibodies to S100. HMB-45 and NKI/C3 (p < 0.001). The variable cell counts suggest that S100, HMB-45 and NKI/C3 are markers of melanocytes in normal oral mucosa, but are not constitutively expressed and may be induced during function.

Differential expression of bcl-2 and bax in squamous cell carcinomas of the oral cavity

The bcl-2 oncogene is a member of a family of genes encoding for proteins which regulate apoptosis (programmed cell death). Recent evidence suggests that the bcl-2 protein is regulated by a homologous protein bax which counteracts its effects and promotes apoptosis. Overexpression of bcl-2 has been reported in a number of human cancers, although correlations with tumour differentiation and clinical outcome are conflicting and depend on tumour type and site. We studied bcl-2 and bax protein expression in adjacent serial sections of 30 squamous cell carcinomas of the oral cavity and correlated this with tumour differentiation. Examination of normal epithelium showed bcl-2 expression confined to basal keratinocytes and dendritic cells. The bax immunostaining was seen throughout the thickness of the epithelium but was most intense in the suprabasal cells. Overall, moderate or marked immunostaining for bcl-2 was identified in 18/30 (60%) carcinomas and for bax in 19/30 (63%) tumours. The bcl-2 immunoreactivity was strongest in the poorly differentiated carcinomas where 6/7 (86%) showed strong staining. By contrast, bax immunoreactivity was strongest in the well-differentiated carcinomas with 8/11 (72%) staining strongly. In the well-differentiated tumour islands, there was inverse topographic distribution of bcl-2 and bax, with both proteins showing a pattern that recapitulated normal epithelium. Upregulation of bcl-2 protein was identified in dysplastic epithelium adjacent to invasive tumour and in many cases there was reduced bax immunostaining. These results suggest that alterations of bcl-2 and bax may play a role in the development of squamous cell carcinoma. Furthermore, disturbances of protein expression in dysplastic epithelium suggest a role in the early stages of epithelial carcinogenesis.

Oral presentation of secondary chondrosarcoma arising in osteochondroma of the nasal septum

A case is described in which a midline palatal swelling, on incisional biopsy, showed an ossifying, chondroid lesion with the histologic features of a low-grade chondrosarcoma. Complete excision revealed that the tumour had originated in a benign osteochondroma of the nasal septum.

Adenomatoid hyperplasia of palatal minor salivary glands

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.

Oral mucosal Langerhans' cells

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.

Adenomatoid hyperplasia of oral minor salivary glands

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.

Limitations of flow cytometry in the analysis of CD1a/HLADR+ human oral mucosal Langerhans cells

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.

A clinicopathological and immunohistochemical analysis of primary oral mucosal melanoma

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.

S100 protein in oral biology and pathology

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.

Oncocytoma of the submandibular gland

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.

Oral melanotic macules that develop after radiation therapy

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.

Human oral mucosal melanocytes: a review

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.

A comparative study on tissue processing procedures for the immunohistochemical investigation of oral mucosal Langerhans cells

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.

Erythema multiforme involving gingiva

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.

The de Lange syndrome in association with a bleeding tendency: oral surgical implications

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.

Purified human oral mucosal Langerhans cells function as accessory cells in vitro

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.

Osteoarthrosis, the temporomandibular joint, and Eagle's syndrome

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.

Effect of tobacco and alcohol consumption on the Langerhans cell population of human lingual epithelium determined using a monoclonal antibody against HLADR

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.

A histochemical study on the distribution of melanin in human oral epithelium at six regional sites

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.

Flurbiprofen in human crevicular fluid analyzed by high-performance liquid chromatography

The aim of this study was to determine whether the non-steroidal anti-inflammatory drug, flurbiprofen, which has been shown to be an inhibitor of alveolar bone loss in human periodontal disease, is present in human crevicular fluid (CF) following oral dosing. A method is described whereby routine high-performance liquid chromatography is used to detect the drug in only 20 microliters of CF. 5 volunteers abstained from toothbrushing for 21 days to induce experimental gingivitis and increase the resting flow of CF. 100 mg of flurbiprofen was taken by each volunteer on d 21-28. On d 21 and 28, serum and CF samples were taken prior to dosing and afterwards at 1, 2, 4 and 6 hours. On d 21 the mean peak concentration of the drug in serum was about 11 micrograms/ml and was found between 1-2 h after dosing. The respective values for CF (d 21) were 0.32 micrograms/ml and 4 h. On d 28 flurbiprofen was detected in both fluids prior to dosing. The mean peak concentrations after dosing had increased to 13.13 micrograms/ml (serum) and 0.46 micrograms/ml (CF) although the levels of the drug in CF remained relatively constant throughout the observation period on d 28. The results indicate that flurbiprofen may be detected in human CF after oral administration and that the levels are in excess of the plasma level, which in beagles has been shown to inhibit alveolar bone loss in periodontal disease.