Nucleolar organizer regions (AgNORs) in odontogenic cysts and ameloblastomas

A comparison of proliferative capacity of reticular and erosive variants of oral lichen planus by argyrophilic nucleolar organizer regions method

Background

Oral lichen planus (OLP), an immune mediated disorder, has been recognized since 1869 and is presented as any one of the six variants. Reticular and erosive are the most frequently encountered. Its proliferative capacity can give some information regarding its progression. We adopted the argyrophilic nucleolar organizer regions (AgNORs) method because of its simplicity to use and dependable results. We evaluated AgNORs in basal, suprabasal, and squamous cell layers. We also compared these three layers within two variants, reticular, and erosive.

Materials and Methods

Thirty clinically diagnosed patients of OLP were included in the study. Reticular and erosive variants were included in our study. This was followed by hematoxylin and eosin staining and later by the AgNOR method. The mean number of AgNORs per nucleus was calculated.

Results

Thirteen males and 17 females were the gender distribution. Twenty-three (76.67%) had reticular pattern and seven (23.33%) had erosive pattern. The basal cell layer had the highest mean AgNOR compared to suprabasal and squamous layers. Even among, erosive and reticular variants, the former had higher mean AgNOR counts.

Discussion

Our results suggest that the inflammatory infiltrate close to the epithelial cells can alter the proliferation index for the pattern of protein synthesis of these cells. Moreover, the high proliferative index in OLP can be related to a specific immunologic response.

Conclusion

We conclude that AgNOR can be used as a proliferative marker in earlier lesions to detect the severity.

AgNOR as an effective diagnostic tool for determining the proliferative nature of different types of odontogenic cysts

Objective:

To determine the proliferative nature of different types of odontogenic cysts using silver-stained nucleolar organizer region (AgNOR) staining.

Materials and Methods:

Forty histopathological sections of each of odontogenic keratocyst, dentigerous, and radicular growth were taken into study. Two sections were produced using the paraffin block of separate cases, one was stained with hematoxylin and eosin and another segment was stained with silver nitrate method.

Results:

AgNOR staining shows black dots and other parts of nuclei show yellow-brown dots.

Conclusion:

AgNOR, which stain for NOR-related proteins, corresponds to cell multiplication. Their amount regarding the number of AgNORs per cyst can be a good marker of the proliferative action of the cell in aggressive cystic lesion having malignant potential.

Quantitative analysis of Argyrophilic Nucleolar organizer regions in odontogenic cysts and tumor - A comparative study

Background

The nucleolar organizer region (NOR) is by definition part of a chromosome, and nucleolus is a structure containing this chromosomal part and in addition the material which accumulate around the NOR, mostly rRNAs and their precursors as well as specific ribosomal proteins. Argyrophilic Nucleolar organizing region (AgNOR) are silver binding NORs often used to study cell proliferation in various types of tumors.

Aim

Quantitative assessment of Argyrophilic Nucleolar organizing region count and its comparison among dentigerous cyst, keratocystic odontogenic tumor and ameloblastoma.

Material and method

Forty-five histologically confirmed cases, 15 cases each of keratocystic odontogenic tumor, dentigerous cysts and ameloblastomas were examined for Argyrophilic Nucleolar organizing region. The sections were obtained and Argyrophilic Nucleolar organizer regions staining was done for comparing the proliferative capacity among these lesions.

Result

Post hoc analysis for inter-group comparison and one way ANOVA were done in all three groups in this study. P < 0.001 was considered significant. The results of AgNOR counts were higher in KCOTs as compared to ameloblastoma and least in dentigerous cysts. The mean AgNOR counts between the study groups were compared using one way ANOVA test and the differences were found to be significant (P < 0.001).

Conclusion

AgNOR counts were significantly higher in KCOT and ameloblastoma as compared to dentigerous cyst suggesting that these lesions have a higher proliferative capacity than dentigerous cyst. The finding of a significantly higher AgNOR counts in KCOT as compared to ameloblastoma represent a difference in proliferative activity and greater growth potential between these two lesions.

Quantitative assessment of silver-stained nucleolar organizer region in odontogenic cysts to correlate the growth and malignant potentiality

Context:

The most common and important odontogenic cyst involving jaws is the odontogenic keratocyst (OKC) or primordial cyst, the dentigerous cyst and the radicular cyst. These cysts all though do not show similar behavior, they all have the potentiality to recur. Silver nitrate staining of the nucleolar organizer regions (AgNORs) of the benign and malignant lesions is becoming very useful as a diagnostic indicator. Thus, the aim of this study is to assess the diagnostic potential of AgNORs in the cystic epithelium of common odontogenic cysts.

Materials and Methods:

Archived specimens of odontogenic cysts were stained with hematoxylin and eosin stain and AgNOR stain.

Results:

The comparative evaluation of the AgNOR counts was done among the three varieties of odontogenic cysts, i.e., radicular cysts, dentigerous cysts and OKC and were observed that the mean for OKC was significantly higher than that of radicular cyst.

Conclusion:

Therefore, AgNor could be used as an efficient tool for comparative evaluation of microscopic features such as epithelial thickness, surface keratinization and mural proliferation in dentigerous cyst to that of the AgNOR count.

Identification of AgNORs and cytopathological changes in oral lichen planus lesions

OBJECTIVE

To evaluate cytopathological changes in epithelial cells of the oral mucosa of patients with oral lichen planus (OLP) compared with patients without OLP.

SUBJECTS AND METHODS

Swabs were collected from the oral mucosa of 20 patients with OLP (case group) and 20 patients without OLP (control group) using liquid-based cytology. After Papanicolaou staining, the smears were characterized based on Papanicolaou classification and degree of maturation. Nuclear area (NA) measurements, cytoplasmic area (CA) measurements, and the NA/CA ratio were determined from 50 epithelial cells per slide. For quantification of argyrophilic nucleolar organizer regions (AgNORs), the smears were stained with silver nitrate, and the number of AgNORs was counted in 100 cells.

RESULTS

In both groups, there was a predominance of Papanicolaou Class I nucleated cells in the superficial layer. The average values of NA (p>0.05) and CA (p=0.000) were greater in the case group (NA=521.6, CA=22,750.3) compared with the control group (NA=518.9, CA=18,348.0). The NA/CA ratio was 0.025 for the case group and 0.031 for the control group (p=0.004). There was no significant difference between the mean AgNORs values of both groups (p>0.05).

CONCLUSION

The oral mucosa of patients with OLP exhibited significant cytomorphometric changes. However, there was no evidence of malignancy.

Quantitative and qualitative assessment of argyrophilic nucleolar organizer regions in normal, premalignant and malignant oral lesions

Aim

The aim of the study was to assess the cell proliferation and biologic aggressiveness of the lesions by evaluating the significance of number and dispersal pattern of Argyrophillic Nucleolar organizing Regions (AgNORs) using silver colloid technique in normal mucosa, premalignant and malignant lesions.

Settings and Design

In-vitro study, lab setting.

Methods and Material

The study sample consisted of five groups each with a sample size of 10 and a control group. Group I (Control), Group II (Oral Submucous Fibrosis - Mild dysplasia), Group III (Oral Submucous Fibrosis - Moderate dysplasia), Group IV (Leukoplakia - Mild dysplasia), Group V (Leukoplakia - Moderate dysplasia) and Group VI (Squamous cell carcinoma). Two sections were cut, of which one was stained with H/E stain for histopathological analysis and the second one with Silver nitrate for AgNOR counting and grading. The data obtained were analyzed both qualitatively and qualititavely.

Statistical Analysis Used

Student's Unpaired T test and One- way ANOVA.

Results

The Mean AgNOR count increased in the following ascending order: i.e OSMF with mild dysplasia, leukoplakia with mild dysplasia, OSMF with moderate dysplasia, leukoplakia with moderate dysplasia and squamous cell carcinoma. Qualititatively, Type II AgNOR pattern was found to be the predominant one in all the samples. Type III AgNOR pattern was found to be increasing with the increase in the grade of dysplasia.

Conclusions

AgNOR quantity is proportional to the proliferative activity of the cell and does not necessarily always indicate malignancy. It is the qualitative characteristics of AgNOR that help to differentiate the premalignant and malignant lesions.

Odontogenic epithelial proliferation is correlated with COX-2 expression in dentigerous cyst and ameloblastoma

Investigation of cyclooxygenase (COX)-2 in dentigerous cyst and ameloblastoma may help to improve understanding of the nature and behavior of odontogenic cysts and tumors, and in addition may eventually represent a definitive target for a pharmacological approach in the management of these lesions. The aim of this study was to evaluate COX-2 expression and its correlation with the proliferation of odontogenic epithelium in these lesions. Dentigerous cysts (n=16) and ameloblastomas (n=17) were evaluated. Detection of Ki-67 and COX-2 protein expression was conducted by immunohistochemistry. Data were statistically analyzed using Mann-Whitney U test and Spearman's rank correlation coefficient. No significant differences were found in the expression of Ki-67 and COX-2 between dentigerous cysts and ameloblastomas (P>0.05). A significant positive correlation (P=0.018) and highly significant positive correlation (P=0.004) were found between Ki-67 and COX-2 expression in the odontogenic epithelium of dentigerous cyst and ameloblastoma, respectively. COX-2 was expressed in the odontogenic epithelium of dentigerous cyst and ameloblastoma. It may contribute to local extension of these lesions by increasing the proliferation of their odontogenic epithelial cells.

Analysis of silver stained nucleolar organizing regions in odontogenic cysts and tumors

Objective:

The present study aimed to investigate the probable differences in cell proliferation index of odontogenic cysts and tumors by means of a comparative silver stained nucleolar organizing region (AgNOR) quantification.

Study Design:

This descriptive cross-sectional study was done on archival paraffin blocks (n = 62), consisting of 10 odontogenic keratocysts, 10 dentigerous cysts, 10 radicular cysts, 10 conventional ameloblastomas, 10 adenomatoid odontogenic tumors, 10 calcifying epithelial odontogenic tumors and 2 ameloblasic carcinomas.

Results:

The mean AgNOR count of odontogenic cysts was 1.709 and the benign odontogenic tumors was 1.862. Highest AgNOR count was recorded in odontogenic keratocyst and lowest was seen in radicular cyst. Statistically significant difference in AgNOR counts of ameloblastoma and adenomatoid odontogenic tumor, amelobalastoma and calcifying epithelial odontogenic tumor, benign odontogenic tumors and ameloblastic carcinoma were seen. AgNORs in ameloblastic carcinoma were more in number and more widely spread.

Conclusion:

AgNOR technique may be considered a good indicator of cell proliferation in odontogenic cysts and tumors.

Analysis of the proliferative potential of odontogenic epithelial cells of pericoronal follicles

AIM

To evaluate the proliferative potential and the cell proliferation rate of odontogenic epithelial cells.

MATERIALS AND METHODS

Forty-two cases of pericoronal follicles of impacted third molars were submitted to silver impregnation technique for quantification of argyrophilic nucleolar organizer regions (AgNOR) and immunohistochemical staining for EGFR and Ki-67. For AgNOR quantification, the mean number of active nucleolar organizer regions per nucleus (mAgNOR) and the percentage of cells with 1, 2, 3 and 4 or more AgNORs per nucleus (pAgNOR) were quantified. Ki-67 immunolabeling was quantified, whereas for EGFR, a descriptive analysis of staining patterns (membrane, cytoplasm or membrane + cytoplasm positivity) was performed. We evaluated the reduced epithelium of the enamel organ and/or islands of odontogenic epithelium present in the entire connective tissue.

RESULTS

mAgNOR were 1.43 (1.0-2.42) and were significantly different among pericoronary follicles from upper and lower teeth (p = 0.041). Immunostaining of Ki-67 was negative in all cases. EGFR immunolabeling was found mainly in the cytoplasm and was more intense in islands and cords when compared to reduced epithelium of the enamel organ.

CONCLUSION

Odontogenic epithelial cells of some pericoronal follicles have proliferative potential, suggesting their association with the development of odontogenic lesions.

CLINICAL SIGNIFICANCE

The authors suggest that nonerupted, especially of the lower teeth, should be monitored and if necessary removed.

A qualitative and quantitative analysis of AgNORs in keratocystic odontogenic tumor, unicystic ameloblastoma and multicystic ameloblastoma

AIMS

A comparative evaluation of proliferation activity in unicystic ameloblastoma (UA), multicystic ameloblastoma (MA) and keratocystic odontogenic tumor (KCOT) using silver staining technique.

SETTINGS AND DESIGN

In the present study 21 histopathologically confirmed paraffin blocks,7 each of UA, MA and KCOT were selected and stained with silver nitrate.

MATERIALS AND METHODS

For quantitative analysis, 100 cells were counted at 1000x magnification for AgNORs and the mean value was calculated. Qualitative analysis of AgNORs included normal (oval shaped) and abnormal groups (bean shaped) in the lesion.

STATISTICAL ANALYSIS

The statistical analysis of data was done by a specialist statistician using two way ANOVA and multiple comparisons with Tukey's test in advanced excel.

RESULTS

The AgNOR count was more in KCOT when compared to MA and UA with the pattern of distribution of AgNORs more in basal than in the parabasal layer in KCOT. The qualitative analysis showed small to large oval AgNOR's in KCOT and few clusters in MA whereas in UA irregular clusters were seen.

CONCLUSION

This concludes the expediency of AgNOR staining in reflecting the high proliferation rate and a more aggressive behavior of KCOT in comparison to MA and UA which signifies requirement of a more hostile surgical approach in KCOT to avoid recurrences following different treatment modalities.

Avaliação do metabolismo epitelial em cistos radiculares pela técnica de AgNORS

Introdução: A formação do Cisto Radicular (CR) está associada à proliferação dos restos epiteliais de Malassez por estímulos inflamatórios, provenientes da proliferação bacteriana do canal radicular de um dente não vital. Quando o dente é removido, esse cisto passa a ser denominado Cisto Residual (CRe). O tratamento de escolha para o CR é endodôntico, com o objetivo de eliminar a inflamação presente no periápice. No entanto, em alguns casos, o cisto pode continuar a crescer, necessitando de tratamento cirúrgico, o que ocorre na maioria dos casos de CRe. Objetivo: Avaliar o metabolismo do epitélio de revestimento de CR e CRe, utilizando a quantificação das AgNORs, e verificar a influência da presença de inflamação sobre o crescimento desses cistos. Material e método: Vinte casos de CR e dez de CRe foram submetidos à técnica de AgNOR. A análise quantitativa das NORs foi realizada utilizando-se o software 'Contando células'. O teste estatístico pós-hock de Newman-keuls foi realizado para a comparação do número médio de AgNORs entre CR e CRe, e entre áreas inflamadas e não inflamadas. Resultado: Diferença estatisticamente significante (p=0,0094) foi observada entre áreas inflamadas (1,86±0,26) e não inflamadas (1,65±0,20). Na comparação entre CR (1,81±0,28) e CRe (1,73±0,16), não houve diferença estatisticamente significante (p=0,37). Conclusão: A inflamação interfere no metabolismo epitelial de CR e CRe, o que reflete a ação de fatores de crescimento na proliferação do epitélio, contribuindo para o crescimento do cisto, independentemente da presença do fator etiológico associado com a origem da lesão.

Diagnostic dilemma of unicystic ameloblastoma: novel parameters to differentiate unicystic ameloblastoma from common odontogenic cysts

AIM

Diagnostic criteria that have been specified for unicystic ameloblastomas (UAs) are not always helpful to differentiate these cystic tumors from common odontogenic cysts. The aim of this study therefore was to identify additional histopathological features (other than the features considered for the diagnosis of UA at present) that would be helpful to differentiate UA from odontogenic cysts.

METHODS

One hundred histopathologically confirmed unicystic ameloblastomas and 20 cases each of radicular, inflamed dentigerous and non-inflamed dentigerous cysts were selected. Histopathological features of the UAs that are not used as diagnostic criteria at present were identified.

RESULTS

Hyperplastic arcading epithelial proliferations with stellate-reticulum-like and vacuolated cells were always seen associated with inflammation in odontogenic cysts, while in UA plexiform-like areas were also seen without inflammation (P < 0.001). In addition, a spiky rete pattern was observed in non-inflamed UA while this pattern was observed only in inflamed odontogenic cysts. Furthermore, spiky retes together with subepithelial hyalinization were usually observed in UAs while only subepithelial hyalinization was observed in non-inflamed dentigerous cysts.

CONCLUSIONS

Combinations of histopathological features were identified to differentiate non-inflamed UA from common odontogenic cysts. However, presence of inflammatory changes in UA precludes the use of features identified in the present study for diagnostic purposes.

Molecular biomarkers of cell proliferation in ameloblastomas

Cell proliferation is a vital biological process that is important for all living organisms because of its role in growth and the maintenance of tissue homeostasis. The control of this important process differs greatly among benign and malignant neoplasms, and the evaluation of cell proliferation in neoplasms has become a common tool used by pathologists to provide useful information pertaining to diagnosis, clinical behavior, and treatment. The usefulness of information regarding cell proliferation has led to numerous studies on the value of these methods for diagnosing different types of tumors and for clinical decision making. Ameloblastomas are no exception. This review discusses the use of several classical molecular proliferation markers, including Ki-67, proliferating cell nuclear antigen, cyclin D1 and DNA topoisomerase II alpha, to characterize ameloblastomas and proposes the use of new proliferation markers used previously to characterize other neoplasms. The use of these biomarkers offers valuable opportunities to evaluate the biological behavior of this type of odontogenic tumor.

Keratocystic odontogenic tumors: predictive factors of recurrence by Ki-67 and AgNOR labelling

PURPOSE

The purpose of the present study was to investigate the possible role of Ki-67 and argyrophilic nucleolar organizing regions (AgNOR) between the recurrent and nonrecurrent keratocystic odontogenic tumors (KCOTs). Another aim was to compare the correlation between these two markers.

MATERIALS AND METHODS

22 KCOTs were evaluated retrospectively. The actual proliferative activity of the KCOT was measured by Ki-67 labelling index and argyrophilic nucleolar organizing regions AgNOR count per nucleus.

RESULTS

Recurrence occurred in 3 patients (13.6%) during the follow-up period (mean follow-up, 37.8 months) The Ki-67 and AgNOR counts were significantly higher in the recurrent lesions comparing to the non-recurrent lesions. (p=0,045; p=0,049) The correlation between Ki-67 and AgNOR counts was found to be positive (r=0,853 p=0,0001).

CONCLUSION

Within the limit of the present study, it is thought that Ki-67 and AgNOR might be helpful as a prognostic marker for the recurrences of KCOTs. These markers reinforced the meaning of the new classification of the lesion as an odontogenic tumor. Enucleation with curettage or decompression following enucleation with curettage is a simple and appropriate surgical model for the treatment of KCOT despite the relative high recurrence rate. On the other hand, the conservative treatment can be chosen only if there is no coronoid invasion, no interruptive cortical lysis and no tissular invasion.

Nucleolar organizing regions and alpha-smooth muscle actin expression in a case of ameloblastic carcinoma

Ameloblastic carcinoma is a rare lesion of odontogenic origin. It is defined as a malignant epithelial odontogenic tumor that histologically has retained the features of ameloblastic differentiation and also exhibits cytologic features of malignancy, like atypia and mitotic activity. Although this lesion represents a separate entity, differentiating it from ameloblastoma has been often challenging to pathologists. In this case study reporting a case of ameloblastic carcinoma, we have attempted to verify the previous findings on the use of Argyrophilic nucleolar organizing regions (AgNORs) and immunohistochemical staining for the alpha-smooth muscle actin (alpha-SMA) in differentiating ameloblastic carcinoma from ameloblastoma. It was observed that AgNORs was found to be almost twice in ameloblastic carcinoma as it was in ameloblastoma. A difference between the two lesions in the pattern of expression of alpha-SMA was also observed, with alpha-SMA being expressed in the odontogenic epithelium and the stroma of ameloblastic carcinoma whereas, in the case of ameloblastoma, it was found only in the stromal part. These findings suggest that AgNORs and alpha-SMA expression may be used as adjuncts to the routine histopathologic examination to differentiate ameloblastic carcinoma and ameloblastoma.

Actual Proliferating Index and p53 protein expression as prognostic marker in odontogenic cysts

BACKGROUND

The purpose of this study was to evaluate the biological aggressiveness of odontogenic keratocyst/keratocystic odontogenic tumour (KCOT), radicular cyst (RC) and dentigerous cyst (DC) by observing the actual proliferative activity of epithelium, and p53 protein expression.

METHODS

The actual proliferative activity was measured by Ki-67 Labelling Index and argyrophilic nucleolar organizing regions (AgNOR) count per nucleus. The p53 protein expression was also evaluated.

RESULTS

Ki-67 positive cells were observed higher in suprabasal cell layers of KCOT with uniform distribution, a few of them were predominantly observed in basal cell layer in RC and DC. The AgNOR count was significantly higher in suprabasal cell layers of KCOT. The actual proliferative activity was noted to be higher in suprabasal cell layers of KCOT. The p53 immunolabelling was dense and scattered in basal and suprabasal cell layers in KCOT. The weakly stained p53 positive cells were observed diffusely distributed in KCOT, whereas they were mainly seen in basal cell layer of RC and DC.

CONCLUSION

The quantitative and qualitative differences of the proliferative activity and the p53 protein expression in sporadic KCOT may be associated with intrinsic growth potential that could play a role in its development and explain locally aggressive biological behaviour. AgNOR count and p53 protein detection in odontogenic lesions can be of great consequence to predict the biological behaviour and prognosis.

Quantitative analysis of argyrophilic nucleolar organizer regions and epidermal growth factor receptor in ameloblastomas

OBJECTIVE

The aim of this study was to evaluate the proliferation activity by means of the quantification of the argyrophilic nucleolar organizer regions (AgNORs) and the patterns of expression of the epidermal growth factor receptor (EGFR) in ameloblastomas.

METHOD

The methods of evaluation included the H/E stain for the morphologic analysis, the silver impregnation technique for quantification of the AgNORs and the immunohistochemical stain with anti-EGFR antibody in 11 cases of ameloblastoma.

RESULTS

The results did not show a significant statistical difference as per quantification of the AgNORs. The expression of the EGFR on the epithelial islands of ameloblastoma was not uniform, and the location of the expression was also variable. The predominant expression was that of cytoplasm and the islands with an expression of membrane only were rare and generally smaller in size.

CONCLUSION

The tumor presents an irregular growth. Smaller islands are associated with a higher proliferation activity and therefore could be responsible for tumor infiltration.

Histopathologic comparison of normal and hyperplastic condyles

OBJECTIVE

The aim of this study was to compare normal and hyperplastic mandibular condyles using two different histopathologic staining techniques.

STUDY DESIGN

Nine cases of condylar hyperplasia and 13 normal cases were studied after hematoxylin and eosin and silver staining.

RESULTS

There was a significant difference between the two groups in the thickness of the hyperplastic cartilage layer of condylar soft tissue (P = 0.017). Also, the number of argyrophilic nucleolar organizer regions was significantly higher in the condylar hyperplasia case group (P = 0.0001). No significant differences could be demonstrated in cartilage island frequency, penetration depth, and distribution in the cancellous bone of condyles.

CONCLUSION

The thickness of the hyperplastic cartilage layer appears significantly increased in condylar hyperplasia. In addition, argyrophilic nucleolar organizer region count may be useful in histopathological identification of condylar hyperplasia.

Nucleolar organizer regions in selected odontogenic lesions

OBJECTIVE

The present study aimed to assess the usefulness of argyrophilic nucleolar organizer regions (AgNORs) as quantitative criteria in the diagnosis of odontogenic cysts and tumors.

STUDY DESIGN

This descriptive cross-sectional study was done on archival paraffin blocks (n = 37), consisting of 10 conventional ameloblastomas, 7 cases of unicystic ameloblastoma, 10 odontogenic keratocysts, and 10 dentigerous cysts, all accessioned between 1994 and 2000.

RESULTS

The findings showed a significant statistical difference among the 4 lesions (P <.001). Conventional and unicystic ameloblastomas had a significantly higher (P <.05) number of AgNORs than odontogenic keratocysts and dentigerous cysts. No significant differences were observed within each group of tumors or cysts. The number of AgNORs was also significantly higher (P <.005) in the nuclei of basal layer cells of the epithelial lining of keratocysts than in the nuclei of parabasal layer cells. AgNORs in conventional and unicystic ameloblastomas were smaller but more broadly distributed, which may indicate higher proliferative activity.

CONCLUSION

AgNORs can be useful in the histopathologic differentiation of ameloblastomas from odontogenic cysts.

Nucleolar organizer regions (NORs) evaluation of lingual salivary glands of chronic alcoholics

BACKGROUND

Chronic alcoholism has been associated with structural and physiological changes in salivary glands. Studies on a variety of pathologies have suggested that variation in number of nucleolar organizer regions (NORs) reveals conditions of cellular activity. The aim of this work was to examine, through the AgNOR technique, changes in number and size of NORs in lingual salivary glands of chronic alcoholics.

METHODS

Samples of mucous and serous lingual salivary glands were obtained from tongues from autopsies of individuals whose cause of death was hepatic alcoholic cirrhosis. Lingual organs from individuals whose cause of death was accidental were used as controls. Number and size of the AgNORs and nuclear area, in ductal and acinar cells, were evaluated through a digital image analyzer.

RESULTS

Statistical analysis revealed differences (P < or = 0.05) in number of AgNORs in mucous acini and ductal cells. Also, we observed changes in the area of the NORs.

CONCLUSION

These results suggest that in alcoholics the activity of glandular cells, mainly in ductal epithelium, could be affected, modifying synthesis, transport and salivary secretions.

The aggressive nature of the odontogenic keratocyst: is it a benign cystic neoplasm? Part 1. Clinical and early experimental evidence of aggressive behaviour

In this, the first of three articles on the aggressive nature of the odontogenic keratocyst (OKC), there is a review of clinical and histological observations which indicated that this was an aggressive lesion with a predilection for recurrence unlike the majority of other jaw cysts. This led to the tentative suggestion that the OKC might be a benign neoplasm. Subsequently there were early laboratory investigations that compared proliferation rates of the OKC epithelium with other jaw cysts, comparative enzyme histochemistry to assess aspects of its metabolism and markers that would enable accurate presurgical diagnosis of this cyst. Comparative studies were also pursued on the walls of the OKC and other jaw cysts to identify factors that might influence the capacity of the OKC to resorb the bone surrounding it. The clinical and laboratory studies reviewed in this section provided cogent presumptive evidence of the distinctively aggressive nature of the OKC that led numbers of investigators to pursue immunocytochemical and genetic studies on this cyst. Parts 2 and 3 of this series review this work.

Identification of the AgNORs, PCNA and ck16 proteins in oral lichen planus lesions

The expression of proliferating cell nuclear antigen (PCNA), cytokeratin 16 (ck16) and Ag nucleolar organizer regions (AgNORs) were assessed in 20 cases of lichen planus, 20 cases of keratosis and 20 cases of normal oral mucosa in order to evaluate the rate of keratinocyte proliferation in these tissues. Three hundred cells were counted in each sample: 100 basal cells, 100 suprabasal cells and 100 squamous cells. The mean number of AgNORs and the percentage of PCNA positive cells were calculated. Except from similar staining of suprabasal cells of lichen planus and keratosis, PCNA and AgNORs values were higher in all layers of lichen planus than in both keratosis and normal oral mucosa. The three groups showed similar ck16 immunostaining: all of the cells were positive, except those of the basal layer. The results suggest that the keratinocyte proliferation index is higher in lichen planus than in keratosis and normal mucosa. Besides, ck16 should not be used to differentiate the entities studied.

Use of calretinin in the differential diagnosis of unicystic ameloblastomas

AIMS

Calretinin, a 29-kDa calcium-binding protein is expressed widely in normal human tissues and tumours including both unicystic and solid and multicystic ameloblastomas. The histological distinction between unicystic ameloblastomas and certain non-neoplastic odontogenic cysts can be problematic. The objective of this study was to determine whether calretinin was expressed in the lining epithelium of odontogenic keratocysts, residual and dentigerous cysts and to determine whether this calcium-binding protein could be used to distinguish these cysts from the unicystic ameloblastoma.

METHODS AND RESULTS

The lining epithelium in 22 cases of odontogenic keratocyst, 26 cases of residual cyst and 20 cases of dentigerous cyst were examined for the expression of calretinin. No positive epithelial staining was observed in any of these cystic lesions. In comparison, however, 81.5% of cases of unicystic ameloblastoma showed a coarse dark brown staining of the more superficial epithelial cell layers. Scattered positive stromal and epithelial cells were present; these were interpreted as mast cells.

CONCLUSIONS

Calretinin appears to be a specific immunohistochemical marker for neoplastic ameloblastic epithelium and we suggest that it may be an important diagnostic aid in the differential diagnosis of cystic odontogenic lesions and ameloblastic tumours.

Argyrophilic nucleolar organizer regions (AgNORs) in ameloblastomas and adenomatoid odontogenic tumours (AOTs)

Twenty-two cases of ameloblastoma and ten cases of adenomatoid odontogenic tumour (AOT) were analyzed comparatively by the AgNOR technique. Ameloblastomas were distributed into three groups according to their clinical behaviour: primary lesions without recurrences (PLWTR), 5 cases; primary lesions with recurrences (PLWR), 4 cases; and recurrences, 13 cases. The cases were also regrouped according to their histological pattern: follicular (9 cases), plexiform (7 cases), acanthomatous (4 cases) and unicystic (2 cases). Considering histological patterns, there was a significant statistical difference only between follicular and plexiform types. There were no significant differences between the group of ameloblastomas and the group of AOTs or between the three groups of ameloblastomas with different clinical behaviour. Our results strongly suggest that the distinct clinical behaviour of ameloblastomas and AOT is not correlated with their cellular proliferation ratio. Thus, the infiltrative ability of the ameloblastomas is probably not related to the cellular proliferation index of these tumours.