p53 expression in dyskeratosis congenita: a marker for oral premalignancy?

As p53 expression has been associated with malignant disease its presence was assessed in biopsy specimens from dorsal lingual hyperkeratosis, taken over a five year period. p53 expression, using CM1, was assessed using a standard immunoperoxidase technique. p53 was not identified in the first biopsy specimen in 1986 but was identified in all subsequent ones. Only in the latest biopsy specimen was there evidence for dysplasia in haematoxylin and eosin stained sections. It is suggested that p53 expression may be a reliable marker for predicting premalignant change in keratoses occurring in dyskeratosis congenita.

p53 protein in odontogenic cysts: increased expression in some odontogenic keratocysts

AIMS

To assess p53 protein expression in a range of odontogenic cysts arising in the mouth, including those of developmental and inflammatory origin.

METHODS

p53 protein was identified using the polyclonal antibody CM-1, together with a standard immunoperoxidase technique. A total of 36 cystic lesions were examined, all of which were histologically benign.

RESULTS

Expression of p53 protein was identified within the lining of five of 12 odontogenic keratocysts but was not detected in the other cystic lesions in the series.

CONCLUSIONS

This is believed to be the first report that identifies increased expression of p53 protein in benign cystic epithelium. The increased expression of p53 protein in the nucleus is usually associated with malignant disease. These findings are relevant to the management of odontogenic keratocysts which have a tendency to recur, and also to Gorlin Goltz syndrome in which keratocysts and multiple basal cell carcinomas are features.

Cytokeratin profiles in dyskeratosis congenita: an immunocytochemical investigation of lingual hyperkeratosis

In dyskeratosis congenita, the hyperkeratotic lesions affecting the mucous membranes have a propensity to undergo malignant change. Unfortunately there is presently no reliable method for predicting such an outcome. Oral mucosal biopsies were obtained from a case of dyskeratosis congenita and keratin expression identified using a panel of antikeratin antibodies. Marked changes were found from keratin profiles established for normal oral mucosa. In particular coexpression of three separate type 1 keratins (K16, K10 and K13) were observed in the ventral tongue lesion. The keratin pattern found in the tissue biopsies examined is suggestive of an unusually immature or disturbed state of tissue differentiation, and as such may be indicative of future malignant change.

Cytokeratin expression in oral exfoliative cytology: effect of temperature and fixation

The identification of keratin expression within oral cytology may be useful in the diagnosis of clinically suspicious oral mucosal lesions. There may be wide variation in the temperature at which such smears are stored, prior to processing. Conventionally, rapid fixation or storage at low temperatures is recommended to preserve kertin expression within tissue biopsies. No previous study has assessed whether this is true for oral cytology. Smears were taken from clinically normal buccal mucosa. For each temperature assessed (-70, -40, -22, +5, +20 and +26 degrees C), one smear was spray-fixed (Vale Smear Fix) and one air-dried, prior to storage for 4 days, and then staining with the pan-epithelial antikeratin antibody, LP34. Preservation of keratin expression was assessed as either weak (zero to few positive cells) or strong (most cells positive). The results were analysed using logistic regression with the statistical modelling package, GLIM. Over the range of temperatures studied, spray fixation did not appear to improve the identification of keratin expression. Although the best preservation was obtained at lower temperatures, keratin expression was still adequate after 4 days at 20 degrees C. Hence, a delay in processing of 4 days would still allow detectable expression in oral exfoliative cytology even at room temperature.

Preservation of keratin expression in oral mucosa using a novel transport medium

Cellular expression of keratins (intermediate filaments) can be demonstrated by immunocytochemistry using unfixed tissue. However, for practical reasons, provision of fresh tissue to the laboratory is often difficult. Recently a fresh tissue transport medium (Patent applied for) has been developed which allows keratin immunocytochemistry to be performed up to 4 days after biopsy. In this study oral mucosal biopsies from 10 patients were hemisected, half placed in the new transport medium at 4 degrees C and the other half immediately frozen in liquid nitrogen. After 4 days frozen sections of both halves of the biopsies were stained by immunocytochemistry using various antikeratin antibodies. The morphology and staining characteristics of the two halves of the biopsies were then assessed. No significant difference could be found in either morphology or preservation of keratin expression in specimens stored in transport medium, as compared to those in liquid nitrogen. This new transport medium may offer considerable advantage for the provision of a histologic and immunocytochemical diagnostic service.

Lingual hyperkeratosis in dyskeratosis congenita: ultrastructural findings

The first ultrastructural description of the mucosal lesions of lingual hyperkeratosis in dyskeratosis congenita is reported. The histology described may help explain the high incidence, later in life, of cancerous change in these leukoplakic patches.

An analysis of mandibular fractures in Dundee, Scotland (1977 to 1985)

A retrospective study was undertaken to assess mandibular fractures presenting over the period 1977-1985 in Dundee, Scotland. The data collected included age, sex, aetiology, month in which injury occurred, anatomical site of fracture, associated maxillofacial trauma and treatment modalities. The majority of fractures were sustained by males in the age group 20 to 29 years. Assault was the major cause of trauma followed by falls and road traffic accidents. The posterior body region was found to be the most common fracture site in the mandible. The level of such trauma has more than doubled, since a similar study was undertaken between the years 1961 to 1970.

Langerhans cells in human chronic gingivitis and phenytoin-induced gingival hyperplasia

Langerhans cell numbers in oral epithelium increase as dental plaque accumulates. The anti-convulsant drug phenytoin predisposes to gingival hyperplasia in certain patients who take this medication for epilepsy and who also have poor oral hygiene. In this study 7 patients with phenytoin-induced gingival hyperplasia were compared with 5 subjects with chronic marginal gingivitis. On initial examination and on completion of the hygiene phase of periodontal therapy (a period ranging from 3.0 to 4.25 months), clinical indices of plaque and gingivitis were recorded and biopsies were taken from the lower anterior labial gingiva. Frozen sections were stained by an immunoperoxidase technique using the monoclonal antibody OKT6, and the number of Langerhans cells in a defined cross-sectional area was counted. In phenytoin-induced gingival hyperplasia there was a marked increase in Langerhans cells (13.8 +/- 0.45) when compared with chronic gingivitis (7.7 +/- 0.31; p less than 0.05). Both groups showed marked reductions in their plaque and gingival indices and numbers of Langerhans cells once treatment had been completed. However, levels of Langerhans cells in the drug-induced hyperplasia remained significantly higher (3.5 +/- 0.26) than in chronic gingivitis (1.5 +/- 0.22; p less than 0.05).

Dyskeratosis congenita: report of a case and review of the literature

A case of dyskeratosis congenita in a 10-year-old white boy is reported. The triad of oral leukoplakia, nail dystrophy, and skin pigmentation was present. Other associated anomalies included dysphagia and varied immunoglobulin levels, although there was no evidence of anemia, pancytopenia, and ocular involvement. Since it may be associated with future malignant change, dyskeratosis congenita should be considered in all cases in which an obscure white lesion exists in the mouth.

Models of protein lateral arrangements in lipid bilayer membranes. Application to electron spin resonance studies of cytochrome c oxidase

We consider the situation of integral membrane proteins in a lipid bilayer matrix where the size of the polar group of the protein is important in determining the lateral packing of the proteins. We represent the cross-section of the protein hydrophobic core as a hexagon moving on a lattice, and represent the projection of the polar group onto the plane of the bilayer as a shape, parts of which overlap the hexagon. Lattice sites represent lipid molecules. We calculate the fraction of lipid molecules which are adjacent to the hydrophobic core of at least one protein. We use this data to consider the "motion restricted" spectrum observed in electron spin resonance (ESR) probe studies, and compute the dependence of the "motion restricted" fraction upon protein concentration. The resulting curves can be used to analyse ESR data in order to deduce the size and shape of the proteins' polar segment. We have used the range of models examined to study the dependence upon protein concentration of the particular case of the "motion restricted" spectrum of a spin-labelled lipid freely diffusing or, alternatively, covalently bound to cytochrome c oxidase. We find that our calculations are in accord with a model where approximately 60 lipid molecules can fit around an isolated such protein in both halves of the bilayer, and where the polar segment is substantially anisotropic and extends laterally beyond the limits of the hydrophobic core. The latter is in accord with what is known about the structure of cytochrome c oxidase. We indicate further measurements that should be performed in order to establish more definitively the dependence of the "motion restricted" component upon protein concentration, giving the lipid protein ratios at which they should be performed, and we make predictions concerning the results. Finally we argue for a particular unified way of plotting experimental data.

The relationship between localization of Na+, K+-ATPase and cellular fine structure in the rat parotid gland

A method for the ultrastructural localization of the Na+-pump enzyme, Na+, K+-ATPase has been applied to the rat parotid gland. A ouabain-sensitive final reaction product, dependent on the presence of K+ and Mg2+, was found to be evenly distributed along the basal and basolateral plasma membranes of acinar and striated duct cells. In both cases, it was localized predominantly in the cytoplasm of the extensive foldings of these membranes. It is concluded that the reaction product meets the criteria for valid localization of this enzyme and that potential Na+-pump sites have been demonstrated. This study supports previous findings in salivary glands and contributes to an increasing body of evidence that contraluminal Na+-pumps are common to both reabsorbing and secreting epithelial cells.

A qualitative and quantitative study of the ageing human labial salivary glands

A series of 36 post-mortem labial salivary glands from both male and female subjects with ages ranging from 25 to 80 yr were examined histologically. Features such as acinar atrophy, fibrous replacement and ductal aberrations were noted in the aged glands. By the stereological method of point counting, the volume proportions of various defined gland constituents were calculated for individual glands in the series. An age-related decrease in acinar volume proportion and an increase in ductal and connective tissue volume proportion is recorded. These changes should be considered when diseased glands are studied.

Blood lymphocytes surface markers and clinical findings in chronic lympoproliferative disorders

Surface receptors on peripheral blood lymphocytes have been studied in 43 cases with chronic lymphocytic leukaemia (CLL), and five cases with lymphoma and overspill. One quarter of the cases with CLL had lymphocytes with no detectable surface immunoglobulin (SIg) by direct fluorescent antibody staining. The remainder had SIgM, which was associated with SIgD in one third of the cases. 70% of the SIg negative group had extensive extramedullary involvement (EMI) compared with 35% of the SIg positive group at presentation; correspondingly more of the SIg negative group were treated. 46% of the SIg negative group were CLL patients of more than 3 years standing compared with 9% of the SIgM+D group and 32% of the SIgM group. Some explanations for this pattern are discussed.

Sarcoidosis with salivary gland involvement: biochemical studies on parotid saliva

Parotid saliva from a patient suffering from sarcoidosis with salivary gland involvement has been shown to have a decreased level of alpha-amylase but increased levels of albumin and lysozyme. These observations suggest that in addition to impaired gland function, gland damage as a result of inflammation had occurred which permitted increased passage of constituents from serum into the gland secretion.

A qualitative and quantitative electronmicroscopic study of the structure of the adenoid cystic carcinoma of human minor salivary glands

The fine structural characteristics of five adenoid cystic carcinomas of human minor salivary galnds and a quantitative assessment of the relative volumes occupied by morphologically defined cell types in these tumors are reported. We observed that the cyst-like spaces which give the characteristic cribriform pattern to the adenoid cystic carcinoma contain replicated basement membrane-like materail. Material comprisimg aggregates of fine tubules having a median diameter of 270 A, and rounded, electron dense bodies were noted within duct-like lumena of one tumor. In addition, dilatation of the intercellular spaces and squamous metaplasia were noted. From 500 electronmicrographs obtained by standardized techniques and used for the morphological part of the study, 175 were selected by a random sampling method and analyzed by the stereological technique of point counting. This method demonstrated that duct type cells occupied 75% by volume of the tumor in these glands; myoepithelial cells occupied 3%, acinar cells occupied 2%, and other tissues occupied 22% of the tumors. These proportions differ significantly (P less than 0.001) from our previously published figures for normal specimens of these glands.