Luminal epithelium of Warthin's tumours: a scanning electron microscopic study.

Three cases of papillary cystadenoma lymphomatosum were examined by light and scanning electron microscope to declare the morphology of the luminal epithelial surface. It was found that ciliated cells were present in one case. This finding explains the origin of ciliated cells as a development included in the neighbouring lymph node with a tendency of metaplastic change and exfoliation.

Variations in nucleolar organizer regions during 9-10 dimethyl1-2 benzanthracene induced tongue carcinogenesis in rats.

The quantitative and qualitative changes of transcriptionally active nucleolar organizer regions (NORs) identified by silver staining (AgNORs) were observed in rat tongue lesions induced by 9-10 dimethyl 1-2 benzanthracene (DMBA). Epithelial hyperplasia, mild, moderate dysplasia and severe dysplasia (with or without invasive squamous cell carcinoma) were induced 4,6,8 & 10 weeks respectively after implantation of 5 mg DMBA in the submucosa of rat's tongues. A general trend towards an increase in the mean AgNOR counts with longer time and resultant histopathological findings was observed, where the lowest value (2.44 +/- 1.00) was found in specimens showing epithelial hyperplasia (4 weeks after DMBA implantation) and the highest value in those showing severe dysplasia with invasive squamous cell carcinoma (10 weeks after DMBA implantation). Clumping and irregularity of AgNOR dots were demonstrated in DMBA treated specimens and were found to increase with higher degrees of epithelia dysplasia. The dispersal of the AgNOR dots in the nucleoplasm indicating high cellular activity was characteristically evident in specimens showing severe dysplasia with invasive squamous cell carcinoma. Our results suggest that although AgNORs can be useful as a qualitative marker of cellular activity at the early stages of DMBA tongue carcinogenesis, counting the AgNOR dots cannot be relied upon in discriminating the different degrees of induced cellular changes.

A clinical and histological comparative study of the effect of nifedipine and phenytion on human gingiva.

Ten patients manifesting gingival enlargement were chosen for this study. Five patients had been treated with 4 mg nifedipine per day as a treatment for angina pectoris, while the other five patients treated with phenytion as an anticonvulsant drug. Clinical and histological data showed that nefidipine induced gingival hyperplasia which is of close similarity to that induced by phenytion despite the differences in target tissue.

Scanning electron microscopic study of argon laser-induced morphologic changes on human dental enamel and dentin.

Thirty-two human posterior teeth were used in this study to investigate the effect of pulsed argon laser of different densities (40, 50 and 60 J/Cm2) on the surface topography of human enamel and dentin. The S.E.M. results showed apparent alterations on the surface topography of both tissues. Increasing the energy density from 40 to 60 J/Cm2 showed a worse, destructive changes. Moreover, the effect of argon laser on dentin was more pronounced when compared with that of enamel irrespective of the energy density used.

Induction of mesenchymal neoplasms by DMBA implantation in deep lingual submucosa of male albino rats.

45 male albino rats were used to study the effect of deep submucosal implantation of DMBA on lingual carcinogenesis. The results showed development of different mesenchymal neoplasms (fibroma, fibrosarcoma and leiomyosarcoma). So, this method of implantation could not be used as an ideal animal model for production of single known neoplasm as had been investigated by many investigators before.

A scanning electron microscopic study of exfoliated malignant oral epithelial cells.

Investigators disagree regarding the value of exfoliative cytology in the diagnosis of oral cancer. The objective of the present study was to examine exfoliated oral epithelial cells from malignant lesions of the oral mucosa by means of Scanning electron microscope (S. E. M.) in order to determine whether SEM surface characteristics might be useful and specific to predict more accurately the nature of these lesions. Twenty cases of squamous cell carcinomas of non keratinized sites of the oral mucosa (Cheek and floor of the mouth) were selected for this study. Exfoliated cells were collected by scraping by means of modified Ayre's spatula and spread over a standard glass microscope slide for light microscope examination, while those for SEM were spread evenly on a plastic square (1 cm2) cut from a polyester sheet of Melinex "O" (Firket 1966). Altered tissue architectures and cell surface architectures were demonstrated in malignant oral lesions. Bizarre cell forms often showing an absence of close cell-cell contact relationships were seen. The observed cell surface patterns were apparently not related to the degree of keratinization when compared to normal surface patterns of corresponding areas of oral mucosa studied in a previous work. These changes appeared to some extent to be related to the clinical diagnosis and to the degree of epithelial atypia observed by the lesions. In conclusion the observations made in this study demonstrate that surface structural differences exist between exfoliated cells from malignant lesions of the oral mucosa and those from corresponding normal non keratinized sites and that the SEM might be of a diagnostic value.