Accuracy assessment of the axial images obtained from cone beam computed tomography.

OBJECTIVE: The aim of this study was to evaluate accuracy of linear measurements assessed from axial tomograms and the influence of the use of different protocols in two cone beam CT (CBCT) units. METHODS: A cylinder object consisting of Nylon® (Day Brazil, Sao Paulo, Brazil) with radiopaque markers was radiographically examined applying different protocols from NewTom 3G(TM) (Quantitative Radiology s.r.l, Verona, Veneto, Italy) and i-CAT(TM) (Imaging Sciences International, Hatfield, PA) units. Horizontal (A-B) and vertical (C-D) distances were assessed from axial tomograms and measured using a digital calliper that provided the gold standard for actual values. RESULTS: There were differences when considering acquisition protocols to each CBCT unit. Concerning all analysed protocols from i-CAT(TM) and Newtom 3G(TM), both A-B and C-D distances presented underestimated values. Measurements of the axial images obtained from NewTom 3G(TM) (6 inch 0.16 mm and 9 inch 0.25 mm) were similar to the ones obtained from i-CAT(TM) (13 cm 20 s 0.3 mm, 13 cm 20 s 0.4 mm and 13 cm 40 s 0.25 mm). CONCLUSION: The use of different protocols from CBCT machines influences linear measurements assessed from axial images. Linear distances were underestimated in both equipments. Our findings suggest that the best protocol for the i-CAT(TM) is 13 cm 20 s 0.3 mm and for the NewTom 3G(TM), the use of 6 inch or 9 inch is recommended.

Substance P regulates the expression of matrix metalloproteinases and tissue inhibitors of metalloproteinase in cultured human gingival fibroblasts.

BACKGROUND AND OBJECTIVE: Substance P may play a role in the pathogenesis of periodontal disease; however, its mechanisms of modulation are not clear. This study evaluated the effect of two concentrations of Substance P on the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in cultured human gingival fibroblasts. MATERIAL AND METHODS: Fibroblasts were stimulated for 48 h with 10(-4) or 10(-9) m Substance P; untreated fibroblasts served as controls. The expression of MMP-1, -2, -3, -7 and -11 and of TIMP-1 and -2 was evaluated using real-time polymerase chain reaction and western blotting. RESULTS: There was a significant, concentration-dependent stimulatory effect of Substance P on MMP-1, -2, -3 and -7 and TIMP-2 gene expression (p < 0.05), and a probable effect on MMP-11 (p = 0.06). At the higher concentration (10(-4) m Substance P), MMP-1, -2, -3, -7 and -11 and TIMP-2 showed the greatest up-regulation; at the lower concentration (10(-9) m Substance P), MMP-1, -3 and -7 and TIMP-2 exhibited diminished up-regulation, with MMP-2 and -11 showing down-regulation (p < 0.05). Expression of TIMP-1 was not affected by Substance P (p > 0.05). Western blotting confirmed that Substance P up-regulated MMP-1, -2, -3 and -11 and TIMP-2. MMP-1, -3 and -11 and TIMP-2 showed greater up-regulation at the higher Substance P concentration and diminished up-regulation at the lower concentration. MMP-2 was up-regulated to a similar degree at both Substance P concentrations. CONCLUSION: In gingival fibroblast cells, Substance P at the higher concentration (10(-4) m) induced greater up-regulation of MMP-1, -3 and -11 and TIMP-2 expression, but at the lower concentration (10(-9) m) induced diminished up-regulation, which may represent a mechanism for modulating periodontal breakdown.

Cytokeratins in epithelia of odontogenic neoplasms.

Neoplasms and tumours related to the odontogenic apparatus may be composed only of epithelial tissue or epithelial tissue associated with odontogenic ectomesenchyme. The immunohistochemical detection of different cytokeratins (CKs) polypeptides and vimentin has made it easier to explain the histogenesis of many epithelial diseases. The present study aimed to describe the immunohistochemical expression of cytokeratins 7, 8, 10, 13, 14, 18, 19 and vimentin in the epithelial components of the dental germ and of five types of odontogenic tumours. The results were compared and histogenesis discussed. All cells of the dental germ were positive for CK14, except for the preameloblasts and secreting ameloblasts, in which CK14 was gradually replaced by CK19. CK7 was especially expressed in the cells of the Hertwig root sheath and the stellate reticulum. The dental lamina was the only structure to express CK13. The reduced epithelium of the enamel organ contained CK14 and occasionally CK13. Cells similar to the stellate reticulum, present in the ameloblastoma and in the ameloblastic fibroma, were positive for CK13, which indicates a nature other than that of the stellate reticulum of the normal dental germ. The expression of CK14 and the ultrastructural aspects of the adenomatoid odontogenic tumour probably indicated its origin in the reduced dental epithelium. Calcifying odontogenic epithelial tumour is thought to be composed of primordial cells due to the expression of vimentin. Odontomas exhibited an immunohistochemical profile similar to that of the dental germ. In conclusion, the typical IF of odontogenic epithelium was CK14, while CK8, 10 and 18 were absent. Cytokeratins 13 and 19 labelled squamous differentiation or epithelial cells near the surface epithelium, and CK7 had variable expression.

Salivary duct carcinoma: cytokeratin 14 as a marker of in-situ intraductal growth.

AIMS: The aim of this study was to determine the immunoprofile of salivary duct carcinoma and to differentiate intraductal growth from invasive growth. METHODS AND RESULTS: We applied a panel of antibodies (cytokeratins 7, 8, 13, 14, 19, vimentin and alpha-smooth muscle actin) in five cases of salivary duct carcinoma. This panel is currently used for identification of different components of salivary gland tumours in our laboratory. All tumour cells were positive for cytokeratins 7 and 8. Few neoplastic structures expressed cytokeratin 14 in cells surrounding tumour islands. CONCLUSION: The finding of cytokeratin 14 was important to confirm the in-situ intraductal growth, which probably characterizes this low-grade neoplasm.

Application of immunohistochemistry to the diagnosis of salivary gland tumors.

A panel of antibodies composed of the cytokeratins (CKs), vimentin, and actin was applied to 114 minor salivary gland tumors to evaluate its diagnostic value. The results revealed that luminal cells of intercalated duct-like structures, such as those seen in pleomorphic adenoma, basal cell adenoma, adenoid cystic carcinoma, and epithelial-myoepithelial carcinoma, expressed CKs 7, 8, 14, and 19. The outer cells of these structures exhibited vimentin or vimentin plus muscle-specific actin, but rarely CK14, which is seen particularly in pleomorphic adenoma, in the tubular type of basal cell adenoma, and seldom in the tubular type of adenoid cystic carcinoma. Modified myoepithelial cells of pleomorphic adenoma and myoepithelioma exhibited a variable immunoprofile. CKs 7 and 8 were also observed in acinar cell adenocarcinoma and polymorphous low-grade adenocarcinoma with vimentin in the latter. CK13 was expressed only by canalicular adenoma and mucoepidermoid carcinoma cells. This study showed that the panel of antibodies employed is effective in distinguishing among salivary gland tumors.

Immunohistochemical Mdm2 expression in minor salivary gland tumours and its relationship to p53 gene status.

Mdm2 protein is a cellular regulator of p53 protein activity. Minor salivary gland tumours were investigated for immunohistochemical expression of Mdm2 protein and for p53 gene status. Formalin-fixed sections were submitted to monoclonal antibody anti-Mdm2 through use of the streptavidin-biotin method. Nuclear immunoreactivity was scored 1 (0-25% nuclei positive), 2 (26-50%), 3 (51-75%) and 4 (> 75%). The scores found were: PLGA = 1-4; ACC = 3 and 4; ACA = 2 and 4; PA = 3. Genomic DNA of p53 gene exons 5-8 was examined by polymerase chain reaction and no alterations were detected. The strong immunohistochemical Mdm2 expression may represent an alternative mechanism to the development of salivary gland tumours.

Basal cell adenocarcinoma of the palate with squamous metaplasia.

Basal cell adenocarcinoma is a rare salivary gland tumour, especially in minor glands. The clinical, histological, and immunohistochemical features of a case involving the palate are described. Formalin fixed, paraffin embedded sections of the tumour were examined in haematoxylin and eosin (H&E) sections and also using immunostaining for cytokeratins 7, 8, 13, 14, 18, 19, vimentin, muscle specific actin (HHF35), and laminin. H&E sections showed that the tumour was composed mainly of basaloid cells and a striking feature was the presence of squamous metaplasia. Neural invasion was also conspicuous. Immunohistochemical reactions indicated that cytokeratin 14 was expressed by all tumour cells and vimentin by all cells except those in the areas of squamous metaplasia. The remaining cytokeratins and actin were present in some of the tumour cells, while laminin showed discreet positivity around cell arrangements. The foci of squamous metaplasia and the immunohistochemical findings are helpful in distinguishing basal cell adenocarcinoma from other salivary gland tumours which show basaloid cells.

Diagnosis of HIV infection using saliva samples: comparative study between adults and children.

The use of saliva samples to detect the anti-HIV antibody has been described recently as an interesting alternative in relation to blood samples. We have analyzed 172 saliva samples from HIV positive and negative patients assisted at CASP, 108 of them adults and 64 children, in order to assess the specificity and sensitivity of the GACELISA test. A specificity was found of 85% and 80% respectively for the adult and children groups and sensitivity of 97.7% and 100% respectively for the adult and children groups. The statistical analysis revealed no differences in specificity and in sensitivity between these groups. We concluded that GACELISA test is useful for children.

PCNA/AgNOR and Ki-67/AgNOR double staining in oral squamous cell carcinoma.

This study was performed on oral squamous cell carcinomas (OSCC) in order to investigate the relation between the number of interphase silver-stained nucleolar organizer regions (AgNORs) and the immunolabeling of proliferation-associated markers, using antibodies to Ki-67 and proliferating cell nuclear antigen (PCNA). Fifteen consecutive cases of oral squamous cell carcinoma were used and a double staining technique was performed in order to quantify the number of NORs in PCNA-positive and -negative cells as well as in Ki-67-positive and -negative cells. Our results showed a higher mean number of AgNORs in PCNA- and Ki-67-positive cells than in PCNA- and Ki-67-negative cells. We concluded that there is an association between cell proliferation and AgNOR score in OSCC.

Proliferative activity in peripheral ossifying fibroma and ossifying fibroma.

A proliferative activity study analysing morphometric and quantitative aspects of nucleolar organizer regions (NORs) and proliferating cell nuclear antigen (PCNA) expression was conducted in 10 cases of peripheral ossifying fibroma (POF) and 10 cases of ossifying fibroma (OF). For NOR identification, the silver staining technique (AgNOR technique) was used. PCNA expression was determined by immunohistochemical staining using the PC10 antibody. The AgNOR analysis for the two lesions showed a profile characteristic of benign lesions. OF showed higher AgNOR number and PCNA expression than POF. Our results suggest increased proliferative activity in OF compared with POF.

p53 In biopsies of oral squamous cell carcinoma. A comparative study with a malignancy grading system.

The relationship between the histological grading of malignancy and p53 protein expression was studied in 40 biopsies of oral squamous cell carcinomas. An immunohistochemical analysis was carried out using the streptavidin method preceded by a treatment with citric acid in a microwave oven. All cases were classified according to the histological malignancy grading system proposed by Anneroth et al. (Scandinavian Journal of Dental Research 1987, 95, 229-249). The expression of p53 was found in 62.5% of the carcinomas studied. Positivity of p53 staining showed a correlation with the histological grade of malignancy and with the degree of keratinisation, nuclear polymorphism and number of mitoses.

Immunohistochemical study of linear gingival erythema from HIV-positive patients.

Severe forms of periodontal disease are frequent in patients with acquired immunodeficiency syndrome (AIDS). Linear gingival erythema (LGE) is a progressive disease described in HIV-positive patients and is considered to be an early stage of necrotizing periodontitis. Although clinical and microbiological differences are reported in LGE and non-specific gingivitis (NSG), a comparative immunopathological approach of both has not been performed yet. The purpose of this study was to compare relative populations of T-lymphocytes, B-lymphocytes, neutrophils, macrophages and IgG bearing plasma cells in gingival biopsies from sites exhibiting LGE and from sites exhibiting NSG. A biotin-streptavidin amplified system was used for identification of the following antigens: CD3 (T-lymphocytes), CD20 (B-lymphocytes), elastase (neutrophils), CD68 (macrophages) and IgG (plasma cell's secretors of IgG). The results have demonstrated decrease proportions of T-lymphocytes, macrophages and high percentage of neutrophils and IgG bearing plasma cells in LGE. In contrast with NSG, many neutrophils cells in LGE were found inside oral gingival epithelium. Our results highlight the idea that progressive periodontal disease is not only characterized by increased tissue inflammation, but, in addition, by significant changes in the proportion of specific inflammatory cells. The high number of neutrophils along the gingival epithelium is probably associated with the severe gingival necrosis reported in AIDS patients.

Minor salivary gland tumours. A retrospective study of 164 cases in a Brazilian population.

One hundred and sixty-four cases of intraoral salivary gland tumours retrieved from the files of the Surgical Oral Pathology laboratory of the University of São Paulo (Brazil), between 1970 and 1993, were studied. Of these, 164 tumours, 62% were classified as benign and 38% malignant. The palate was the main site of occurrence of the tumours followed by the buccal mucosa and upper lip. There was a slight predominance for female patients, with a female to male ratio of 1.3:1. The mean age for benign tumours was 39.9 years (40.8 for females, and 39.7 for males). For malignant tumours the mean age was 43.5 years (42.6 for females and 44.7 for males). Pleomorphic adenoma was the most common of the benign tumours, whereas mucoepidermoid carcinoma and adenoid cystic carcinoma were the most common malignant tumours. In general, benign tumours presented as an asymptomatic nodule. On the other hand, pain, ulceration and radiographic changes were more frequently associated with malignant lesions.

Inverted ductal papilloma of minor salivary gland origin: morphological aspects and cytokeratin expression.

Ultrastructural features and cytokeratin expression of inverted ductal papillomas of minor salivary gland origin were studied. Under the electron microscope, an increased number of desmosomes and mucus-like granules in some cells were the most striking features. Immunohistochemical study revealed that tumor cells displayed strongly positive reactions with cytokeratins 13 and 14, and less strong reactions with cytokeratins 7, 8, 18 and 5D3. These results support the hypothesis that an inverted ductal papilloma can be derived from the proximal portion of a salivary gland excretory duct.

Actin versus vimentin in myoepithelial cells of salivary gland tumors. A comparative study.

Vimentin versus actin expression was immunohistochemically studied in myoepithelial cells of 24 salivary gland tumors in which the participation of myoepithelial cells as a tumoral component has been postulated: two basal cell adenomas, seven pleomorphic adenomas, two myoepitheliomas, seven adenoid cystic carcinomas (two tubular, four cribriform, one solid), six polymorphous low-grade adenocarcinomas. Immunostaining was carried out in formalin-fixed tissue serial sections (3 microns) by the avidin-biotin method, using the antibody vimentin (Dako Corp., Carpenteria, Calif.) and the antibody HHF35 anti-muscle actin (Enzo Biochemical, N.Y.). Our results have confirmed positive staining for vimentin in all salivary tumors studied, although in some tumors it was only in focal areas. The staining for the HHF35 antibody to muscle actin was only consistently found in the adenoid cystic carcinomas of the tubular and cribriform patterns. This study suggests that actin is at least somewhat replaced by vimentin in neoplastic tumoral cells. Therefore vimentin can be used to define the participation and distribution of myoepithelial cells in these tumors.

Vimentin in oral squamous cell carcinoma.

The relationship between the histological grading of malignancy and the expression of vimentin and cytokeratin was studied in 43 cases of oral squamous cell carcinoma. Immunohistochemical analysis was carried out with the avidin-biotin method using monoclonal antibody anti-vimentin, and the peroxidase anti-peroxidase method using the polyclonal antibody anti-cytokeratin. All cases were classified according to the histological malignancy grading system proposed by Anneroth. All of the carcinomas were found to express cytokeratin, while 60.4% expressed vimentin. Vimentin was particularly noted in all tumors scored to have highly malignant cells.

Vimentin as a marker of myoepithelial cells in salivary gland tumors.

Thirty-six salivary gland tumors from the Surgical Oral Pathology Service of the University of São Paulo, School of Dentistry, have been examined by immunostaining, using commercially available antibody to vimentin. The samples analyzed included tumors in which the participation of myoepithelial cells as a tumoral component has been postulated, i.e., pleomorphic adenoma, myoepithelioma, epithelial-myoepithelial adenoma, monomorphic adenoma, adenoid cystic carcinoma, epithelial-myoepithelial carcinoma, and polymorphous low-grade adenocarcinoma. Our results strongly support the view that vimentin is one of the earliest indicators of neoplastic myoepithelial differentiation.