Nelly Molina-Frechero

Comparison of the value of PCNA and Ki-67 as markers of cell proliferation in ameloblastic tumors

Objectives: The aim of this study was to compare among PCNAand Ki-67 as the most reliable immunohistochemical marker for evaluating cell proliferation in ameloblastic tumors. Study Design: Observational, retrospective, and descriptive study of a large series of ameloblastic tumors, composed of 161 ameloblastomas and four ameloblastic carcinomas, to determine and compare PCNA and Ki-67 expression using immunohistochemistry techniques. Results: When analyzing Ki-67 positivity, the desmoplastic ameloblastoma demonstrated a significantly lower proliferation rate (1.9%) compared with the solid/multicystic and unicystic ameloblastomas and ameloblastic carcinomas (p<0.05), whereas the ameloblastic carcinomas displayed a significantly higher rate compared with all of the other ameloblastomas (48.7%) (p<0.05). When analyzing cell proliferation with PCNA, we found significant differences only between the ameloblastic carcinomas (93.3%) and the desmoplastic ameloblastomas (p<0.05). When differences between the immunopositivity for PCNA and Ki-67 were compared, the percentages were higher for PCNA in all types of ameloblastomas and ameloblastic carcinomas. In all cases, the percentages were greater than 80%, whereas the immunopositivity for Ki-67 was significantly lower; for example, the ameloblastic carcinoma expressed the highest positivity and only reached 48.7%, compared to 93.3% when we used PCNA. Conclusions: In the present study, when we used the proliferation cell marker Ki-67, the percentages of positivity were more specific and varied among the different types of ameloblastomas, suggesting that Ki-67 is a more specific marker for the proliferation of ameloblastic tumor cells. Key words:Ameloblastomas, ameloblastic carcinoma, PCNA, Ki-67, cell proliferation markers.

Comparative expression of syndecan-1 and Ki-67 in peripheral and desmoplastic ameloblastomas and ameloblastic carcinoma

The aims of the present study were to examine whether the pattern of syndecan‐1 expression correlates with cellular proliferation index in desmoplastic ameloblastomas (DA), peripheral ameloblastomas (PA) and ameloblastic carcinomas (AC), and to compare with that previously reported for solid (SA) and unicystic (UA) variants of ameloblastoma. Immunohistochemistry was performed for syndecan‐1 and Ki‐67 in seven ameloblastomas (four DA and three PA) and three AC. Expression of syndecan‐1 was related to the histological subtype of tumors and, in the case of malignancy, to lower expression levels observed in AC (22.5%) than in PA (47.5%) or DA (77.5%) (P < 0.05). Syndecan‐1 expression correlated inversely with Ki‐67 proliferative index: the expression was lower in both types of ameloblastomas (1.5% in DA and 6.4% in PA) than in AC (41.2%; P < 0.05). The present results suggest that the decrease in syndecan‐1 expression and increase in the Ki‐67 index observed in AC is in accordance with its higher aggressiveness as compared to the rare DA and PA. Interestingly, DA had a lower proliferation index as well as the highest levels of syndecan‐1 expression. These data suggest that DA differ from the other types of intraosseous ameloblastomas but more studies are necessary to better understand the role of this protein as a marker in the biological behavior of the epithelial odontogenic neoplasms.

An easy cell counting method for immunohistochemistry that does not use an image analysis program

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Papillary Thyroid Carcinoma: Differential Diagnosis and Prognostic Values of Its Different Variants: Review of the Literature

Papillary thyroid carcinoma is the most common thyroid malignancy, and has an excellent prognosis, even with cervical lymph node metastasis; however, histological variants are considered relevant, which may be associated with familial adenomatous polyposis and tumor aggressiveness. Histological features, such as vascular and/or lymphatic invasion, angiogenesis, multifocality, high cellular proliferation rate, neoplastic cell dissemination, and the histological varieties, are indicative of poor prognosis, together with associated clinical factors: age, sex, and tumor size.

Malocclusion and TMJ disorders in teenagers from private and public schools in Mexico City

Objective: To identify, among Mexican teenagers from public and private schools, the frequency, severity of malocclusion and orthodontic treatment needs, and their possible association with temporomandibular joint disorders. Material and Methods: Fifteen-year-old students were recruited from public and private schools. Clinical findings were registered as follows: oral hygiene status with the Oral Hygiene Index-Simplified, malocclusion using the Dental Aesthetic Index (DAI), and TMJ disorders following WHO criteria. Negative binomial and logistic regression models were constructed for data analysis. Results: A total of 249 fifteen-year old students were included in the study (118 female 47.4%). 68% had a DAI score ≤ 25 (minor or no occlusal anomalies), 18% scored 26-30 (mild anomalies), 7% scored 31-35 (evident anomalies), and 6% scored ≥ 36 (major malocclusion). The most frequent anomalies were dental crowding in 50%, maxillary dental irregularity in 44.6%, mandible irregularity in 41.2% and excessive maxillary overjet in 37.8%. Among the students, 26.1% had clicking/muscle or TMJ pain, of these 12.3% showed pain during palpation. OHI-S > 1 was found in 34% of the participants. The negative binomial model showed an association between DAI score and TMJ disorders (P=0.041). Also the logistic regression model showed an association between malocclusion (DAI>25) and TMJ disorders (OR=2.58, p=0.002). Malocclusion was associated also with poor oral hygiene (OR=1.65, p=0.007), and with attendance to public schools (OR=1.97, p=0.039). Conclusions: TMJ disorders and DAI scores were significantly associated. Screening/Diagnostic programs for ortho-dontic and TMJ-disorders are needed, to identify and offer treatment to teenagers with major malocclusion and TMJ/muscle pain. Key words:Dental Aesthetic Index, DAI, crowding, Temporo Mandibular Joint disorders (TMJ disorders), Temporo Mandibular Disorders (TMD), occlusal anomalies, OHI-S.

The relationship between body mass index and body fat percentage and periodontal status in Mexican adolescents.

Abstract Objective. To assess the association between obesity indicators and the periodontal status of high school students. Materials and methods. High school students (15-year-olds) in Mexico City participated in the survey (n = 257). International Obesity Task Force cut-off values (ISO-BMI) were applied to identify overweight and obesity. Also, bioelectrical impedance analysis was performed to estimate body fat percentage (BF%). The simplified detritus index (DI-S) was used to evaluate oral hygiene. The periodontal community index (CPI) was obtained to assess the periodontal status of the participants. Results. Overweight/obesity was identified in 30.0% of the students. BF% was 37.5% in women and 21.2% in men and 16.7% of the participants smoked and 33.5% of the students presented DI-S >1. Based on CPI, 59.5% of the participants showed good periodontal status (CPI = 0); bleeding on probing without further periodontal involvement was found in 13.6% of the participants (CPI = 1), 23.8% showed a CPI = 2 (dental calculus) and a CPI = 3 (shallow periodontal pockets) was detected in 3.1% of the participants. The results of the multinomial logistical regression model fitting CPI ≥2 identified an association BF% (OR = 1.06), having poor oral hygiene (OR = 20.09) and smoking (OR = 2.49). Similarly, overweight/obesity was associated with CPI ≥2 (OR = 1.78) adjusting for school attended (public school OR = 0.35), oral hygiene (DI-S >1, OR = 23.92) and tobacco consumption (smoker OR = 1.81). Conclusions. Excess body fat indicators were associated with bleeding on probing and dental calculus in adolescents. The relationship between overweight/obesity and periodontal status in adolescents should be considered in oral health preventive programs.

Total lower-eyelid reconstruction: Modified Fricke's cheek flap

The present work reviews a total lower-eyelid reconstruction technique that is currently not widely in use but which, in some cases, has proven to be of great utility in the field of reconstructive plastic surgery of the palpebral area. We performed an observational, longitudinal, descriptive and retrospective follow-up study. A total of 34 cases of non-melanoma skin cancer in which the lower eyelid was completely reconstructed using one flap taken from the cheek (modified Frickes cheek flap) were reviewed. The follow-up time for the patients ranged from several months to 5 years. Analysis was performed using the Pearsons chi-square statistical test in an effort to examine the association between the techniques range of functionality and aesthetic variables. Results were considered significant with a p<0.05. The functional result was regular for 91.2%, poor for 8.8% and excellent for 0% (p<0.05). The aesthetic result was regular for 88.2%, poor for 11.8% and excellent for 0% (p<0.05). The main complications were scleral exposure and temporary ocular chemosis. Frickes lower cheek flap is an easy-to-perform, important and often-necessary technique that, in some cases, has yielded positive functional and aesthetic results. This procedure is performed on an outpatient basis and is optimal for aged patients who present with skin cancer and who require total lower-eyelid reconstruction. The use of this technique is associated with a low complication rate and low morbidity.

Intravascular Papillary Endothelial Hyperplasia (Masson’s Tumor) of the Mouth – A Case Report

We report a rare case of intravascular papillary endothelial hyperplasia (IPEH) of the oral mucosa. This neoplasm, known as Masson’s tumor, is an unusual vascular lesion of proliferating endothelial cells. It is usually confined to the lumen of preexisting vessels or vascular malformations. The principal significance of IPEH is its microscopic resemblance to angiosarcoma and possible misdiagnosis as such. Achieving a correct diagnosis is essential to avoid subjecting a patient to unnecessarily aggressive therapy. For this reason, awareness of this lesion is very important for dermatologists and dentists. In this article, we discuss the clinical features, histopathological characteristics, and management of IPEH and review the pertinent literature.

Prognostic factors and treatment strategies for adult head and neck soft tissue sarcoma

Adult head and neck soft tissue sarcomas are rare and display a variety of histological types and clinical characteristics; they are also associated with a variety of mortality risks. The purpose of this study was to examine all patients treated at the Instituto Nacional de Cancerologia for head and neck sarcoma during a 5-year period. Fifty-one adult patients were examined and treated for head and neck sarcomas from 2004 to 2009. The 51 tumours were histologically re-evaluated by expert pathologists and classified as low, intermediate or high grade sarcomas. A multivariate analysis was performed to evaluate the surgical margins, histological grades, and clinical stages as prognostic factors for the disease. Adult head and neck soft tissue tumours are rare, and they are associated with poor prognosis for patients, especially at clinical stages III and IV. The average survival rate after 2 years is 45%, and most of these patients die because of disease progression and metastases.

Molecular markers of cell adhesion in ameloblastomas. An update.

Ameloblastoma is the most common odontogenic tumor of epithelial origin, and though it is of a benign nature, it frequently infiltrates the bone, has a high rate of recurrence and could potentially become malignant. Cellular adhesion potentially plays an important role in the manifestation of these characteristics and in the tumor biology of ameloblastomas. Losses of cell-cell and extracellular matrix adhesion and cohesion are among the first events that occur in the invasion and growth of tumors of epithelial origin. The present review includes a description of the molecules that are involved in cell adhesion as reported for various types of ameloblastomas and discusses the possible roles of these molecules in the biological behaviors of this odontogenic tumor. Knowledge of the complex mechanisms in which these molecules play a role is critical for the research and discovery of future therapeutic targets. Key words:Ameloblastoma, cellular adhesion, molecular markers, cell-cell adhesion, extracellular matrix-cell adhesion.