HPV-related oropharyngeal carcinoma remains infrequent over 25 years in a Brazilian Oral Pathology Center: A cross-sectional study with literature review.

BACKGROUND: The aim was to evaluate the frequency, clinicopathological features, and HPV status of oropharyngeal squamous cell carcinoma (OP-SCC) and benign HPV-related epithelial lesions of the oropharynx over the last 25 years. Moreover, a literature review was performed to investigate HPV frequency in OP-SCC samples diagnosed in Brazilian Centers. MATERIAL AND METHODS: A cross-sectional study analyzed OP-SCC, squamous papilloma, verruca vulgaris, and condyloma accuminatum, diagnosed from 1997 to 2021. HPV status of OP-SCC was determined by immunohistochemistry and "in situ" hybridization. Bivariate statistics were performed (p≤0.05). For the literature review, MEDLINE/PubMed, Web of Science, EMBASE, and Scopus were searched. Two independent reviewers assessed the studies for eligibility. RESULTS: Cross-sectional: 211 OP-SCC (63.0%) and 124 benign lesions (37.0%) were included. OP-SCC frequency increased gradually over time, whereas benign lesions had steady trends. OP-SCC affected more males (n= 171; 81.0%), though the relative frequency in females rose over time. Smoking (n= 127; 60.2%) was common in OP-SCC. Nineteen OP-SCC (13.0%) were positive for HPV. HPV-positive and HPV-negative tumors had similar clinicopathological features (p>0.05). Benign lesions predominated in middle-aged (n= 32; 26.7%) women (n= 71; 57.3%), in the soft palate (n=101; 81.5%). LITERATURE REVIEW: 32 studies were included, and in 60% of them, HPV frequency in OP-SCC was less than 25%. CONCLUSIONS: OP-SCC prevalence has been increasing, and it was mostly associated with smoking and alcohol rather than with HPV infection in Brazil. Benign lesions had a stationary frequency over the evaluated period.

ALDH1 immunoexpression in epithelial and stromal cells of oral lichen planus and lesions with lichenoid inflammatory infiltrate.

BACKGROUND: Oral Lichen Planus is a potential malignant disorder and shares clinical and histopathological features with other similar lesions. ALDH1 is a specific biomarker for stem cells identification, however its role in stromal cells of immune inflammatory infiltrate has not been explored. The aim of this study was to investigate the ALDH1 immunoexpression in epithelial and stromal cells of Oral Lichen Planus and other lesions with lichenoid inflammatory infiltrate. MATERIAL AND METHODS: 64 samples of Oral Lichen Planus, Oral Lichenoid Lesions, Oral Leukoplakia and Unspecific Chronic Inflammation were included. ALDH1 was evaluated in both epithelium and stromal cells. ALDH1+ cells ≥ 5% were considered positive in epithelium. Stromal cells were evaluated semi quantitatively. Fields were ranked in scores, according to criteria: 1 (0 to 10%); 2 (11 to 50%) and 3 (>50%). The mean value of the sum of the fields was the final score. Statistical differences among groups were investigated, considering p < 0.05. RESULTS: ALDH1 expression in epithelium was low in all groups without difference among them. ALDH1+ cells in the lamina propria were higher for Lichen Planus [2.0], followed by Leukoplakia [1.3], Lichenoid lesions [1.2] and control [1.1] (p<0.05). CONCLUSIONS: ALDH1 immunoexpression in epithelium of lichenoid potential malignant disorders did not show a contributory tool, however ALDH1 in stromal cells of lichen planus might be involved in the complex process of immune regulation associated with the pathogenesis of this disease.

Evaluation of remote teaching in master programs in the Oral Pathology and Oral Medicine during the COVID-19 pandemic. Brazilian multicentric study.

BACKGROUND: With the COVID-19 pandemic, there was a need to adopt online teaching methods in a generalized and sudden way, a situation that led to unprecedented changes in the routine of post-graduate students and research development. This study aimed to analyze the evaluation of remote teaching by graduates of master's degrees and advisors in master's programs in the Oral Pathology and Oral Medicine who needed to adapt to a remote teaching methodology in the pandemic. MATERIAL AND METHODS: This quantitative study evaluated the remote teaching in the perception of master's graduates and advisors from postgraduate programs in Oral Pathology and Oral Medicine. Data were collected through an online Google forms® questionnaire. RESULTS: Participated in the study 14 master graduates and 14 master's advisors. Master graduates evaluated that the professors had a good performance (p=0.001), that the duration of the classes was adequate (p=0.015), that the interaction with professors was satisfactory (p=0.007), that they had good interaction with the advisor (p=0.001), that they were satisfied with the remote guidance process (p=0.038) and that face-to-face practical activities were missed (p=0.002). Master's advisors reported satisfaction with remote teaching, good adaptation (p=0.018) and motivation for remote teaching (p=0.016), they evaluated that students were cooperative in activities (p=0.019) and that face-to-face practical activities were missed (p=0.002). CONCLUSIONS: Despite the difficulties, remote teaching proved to be an effective alternative to face-to-face teaching.

Correlation-Driven Lifshitz Transition at the Emergence of the Pseudogap Phase in the Two-Dimensional Hubbard Model.

We study the relationship between the pseudogap and Fermi-surface topology in the two-dimensional Hubbard model by means of the cellular dynamical mean-field theory. We find two possible mean-field metallic solutions on a broad range of interactions, doping, and frustration: a conventional renormalized metal and an unconventional pseudogap metal. At half filling, the conventional metal is more stable and displays an interaction-driven Mott metal-insulator transition. However, for large interactions and small doping, a region that is relevant for cuprates, the pseudogap phase becomes the ground state. By increasing doping, we show that a first-order transition from the pseudogap to the conventional metal is tied to a change of the Fermi surface from hole- to electronlike, unveiling a correlation-driven mechanism for a Lifshitz transition. This explains the puzzling link between the pseudogap phase and Fermi surface topology that has been pointed out in recent experiments.

Metal-Insulator Transition in VO_{2}: A DFT+DMFT Perspective.

We present a theoretical investigation of the electronic structure of rutile (metallic) and M_{1} and M_{2} monoclinic (insulating) phases of VO_{2} employing a fully self-consistent combination of density functional theory and embedded dynamical mean field theory calculations. We describe the electronic structure of the metallic and both insulating phases of VO_{2}, and propose a distinct mechanism for the gap opening. We show that Mott physics plays an essential role in all phases of VO_{2}: undimerized vanadium atoms undergo classical Mott transition through local moment formation (in the M_{2} phase), while strong superexchange within V dimers adds significant dynamic intersite correlations, which remove the singularity of self-energy for dimerized V atoms. The resulting transition from rutile to dimerized M_{1} phase is adiabatically connected to the Peierls-like transition, but is better characterized as the Mott transition in the presence of strong intersite exchange. As a consequence of Mott physics, the gap in the dimerized M_{1} phase is temperature dependent. The sole increase of electronic temperature collapses the gap, reminiscent of recent experiments.

Universal quantum criticality at the Mott-Anderson transition.

We present a large N solution of a microscopic model describing the Mott-Anderson transition on a finite-coordination Bethe lattice. Our results demonstrate that strong spatial fluctuations, due to Anderson localization effects, dramatically modify the quantum critical behavior near disordered Mott transitions. The leading critical behavior of quasiparticle wave functions is shown to assume a universal form in the full range from weak to strong disorder, in contrast to disorder-driven non-Fermi liquid ("electronic Griffiths phase") behavior, which is found only in the strongly correlated regime.

Anaplastic Wilms' tumour, a subtype displaying poor prognosis, harbours p53 gene mutations.

The genetics of Wilms' tumour (WT), a paediatric malignancy of the kidney, is complex. Inactivation of the tumour suppressor gene, WT1, is associated with tumour aetiology in approximately 10-15% of WTs. Chromosome 17p changes have been noted in cytogenetic studies of WTs, prompting us to screen 140 WTs for p53 mutations. When histopathology reports were available, p53 mutations were present in eight of eleven anaplastic WTs, a tumour subtype associated with poor prognosis. Amplification of MDM2, a gene whose product binds and sequesters p53, was excluded. Our results indicate that p53 alterations provide a molecular marker for anaplastic WTs.

Energy current manipulation and reversal of rectification in graded XXZ spin chains.

This work is devoted to the investigation of nontrivial transport properties in many-body quantum systems. Precisely, we study transport in the steady state of spin-1/2 Heisenberg XXZ chains, driven out of equilibrium by two magnetic baths at their end points. We take graded versions of the model, i.e. asymmetric chains in which some structure gradually changes in space. We investigate how we can manipulate and control the energy and spin currents of such chains by tuning external and/or inner parameters. In particular, we describe the occurrence of energy current rectification and its reversal due to the application of external magnetic fields. We show that, after carefully chosen inner parameters for the system, by turning on an external magnetic field we can find spin and energy currents propagating in different directions. More interestingly, we may find cases in which rectifications of energy and spin currents occur in opposite directions, i.e. if the energy current is larger when flowing from left to right side, then the spin current is larger if it flows from right to left side. We still describe situations with inversion of the energy current direction as we increase the system asymmetry. We stress that our work aims the development of theoretical knowledge as well as the stimulation of future experimental applications.

Successful conservative treatment of osteoradionecrosis of the mandible associated with pathological fracture.

RESULTS: Treatment of patients with osteoradionecrosis (ORN) of the mandible associated with pathologic fractures usually consists of a continuity resection of the mandible, leading to severe impairment of the patient's health and quality of life. Conservative treatment may be alternatively attempted; however, it is not usually employed. Here, we report a successful conservative treatment of ORN associated with pathologic fracture. A 48-year-old black man who had undergone radiotherapy for a squamous cell carcinoma in the tongue 6 years previously sought care complaining of facial swelling and draining episodes. Since the patient was fiercely resistant to any kind of hospital-based therapy, a conservative approach was proposed. Daily irrigations with 2% potassium iodate, followed by 3% oxygenated water, were performed by the patient at his house. In addition, local cleaning and debridement were weekly performed at our dental clinic. Systemic antibiotics were also administered. Throughout the therapy course, bone fragments were spontaneously exfoliated. Resolution of the ulcer and fracture was observed after 6 weeks of treatment. This report shows that ORN may be conservatively managed in specific situations, with good cosmetic and functional

A rare case of sclerosing mucoepidermoid carcinoma arising in minor salivary glands with immunohistochemical evaluation.

Mucoepidermoid carcinomas (MECs) are the most common malignancy of the salivary glands demonstrating a wide range of histologic variants and behavior. However, the sclerosing mucoepidermoid carcinoma (SMEC), a morphologic variant of this tumor is extremely rare and has been described almost exclusively in the major glands. The prominent sclerosis observed may obscure its typical morphological feature resulting in a diagnostic challenge. We describe herein a case of SMEC in a 43-year-old-woman, occurring in the minor salivary glands of palate. To our knowledge only 13 cases have been reported until this moment, being only 2 in minor salivary glands. We also performed the immunohistochemical evaluation of c-erbB-2 and Ki-67, searching for an association with the histopathological findings and behavior.

Inflammatory myofibroblastic tumor of the alveolar mucosa of the mandible.

Inflammatory myofibroblastic tumor is a rare lesion composed of myofibroblastic spindle cells accompanied by inflammatory infiltrate. The objective of this paper is to report an uncommon case of inflammatory myofibroblastic tumor located in the alveolar mucosa of the mandible. A 33-year-old male presented an asymptomatic tumoral lesion, firm, pedunculated, pink-colored, covered by smooth mucosa, with focal ulceration, measuring 30x20x20 mm, located in the left posterior alveolar mucosa. Clinical diagnosis was soft tissue tumor. An excisional biopsy was made. Microscopic examination showed compact fascicular spindle cells proliferation with a diffuse inflammatory infiltrate of plasma cells, lymphocytes, and eosinophils. Large ganglion-like cells were observed. The lesional cells were immunopos-itive to vimentin, a-smooth muscle actin, muscle specific actin, and CD68. Negative immunostain was observed to S-100, Bcl-2, Ki-67, desmin, CD34, and cytokeratin. A diagnosis of inflammatory myofibroblastic tumor was performed. After 28 months of follow-up there was no recurrence. Although no evidence of oral inflammatory myofibroblastic tumor recurrence or malignant transformation has been reported, it has been observed that in inflammatory myofibroblastic tumor of other regions a prolonged follow-up is necessary after surgical excision.

Retrospective analysis of peripheral odontogenic fibroma (WHO-type) in Brazilians.

AIM: The purpose of this study is to present data on a series of peripheral odontogenic fibroma, WHO (World Health Organization)-type (POF), in Brazilians and to compare the results with previously reported studies. METHODS: The study sample was made from the number of POF cases and its synonymies diagnosed from 1950 to 2004 at the Oral Pathology Service of the Federal University of Minas Gerais. The cases were reviewed in hematoxylin-eosin stain and the histological features were evaluated in accordance with the classification WHO. Patient's data about gender, age and race and the lesion's clinical data were obtained from the biopsy request forms, after the definite diagnosis of POF. RESULTS: Seventeen diagnoses of POF were found. Data showed that POF has a higher prevalence in females (88.2%), occurring in the second and fourth decades of life (29.4% each), and in Caucasians (64.7%). The most common location was the posterior region of the mandible (41.1%). It was an asymptomatic lesion (23.5%) with an average size of 1.1 to 2.0 cm (35.2%). The histological findings were: 1) fibroblastic tissue high cellularity (58.8%); 2) scarce odontogenic epithelium (64.7%); 3) inflammation (94.1%) and 4) absence of calcification (58.8%). CONCLUSIONS: Clinical and histological data of POF in Brazilians showed important characteristcs for its diagnosis. This epidemiological data will generate a substantial contribution to the clinical, histological diagnosis and behavior of this lesion.

Nrf2-peroxiredoxin I axis in polymorphous adenocarcinoma is associated with low matrix metalloproteinase 2 level.

Polymorphous adenocarcinoma (PAC) is a malignant epithelial neoplasm that affects almost exclusively the minor salivary glands, generally described as having a relatively good prognosis. Aberrant nuclear factor erythroid 2 (NF-E2)-related factor (Nrf2) activation in tumor cells has been associated with induction of antioxidant enzymes, such as peroxiredoxin I (Prx I) and increased matrix metalloproteinase (MMP) expression. In this context, the aim of the present study was to evaluate the expression of Nrf2 and correlate it with Prx I and MMP-2 secretion in PAC. Thirty-one cases of PAC from oral biopsies were selected and immunohistochemically analyzed for Nrf2 and Prx I. MMP-2 quantification was performed on primary cell cultures derived from PAC. Oral squamous cell carcinoma (OSCC) cell cultures were used as control. A high immunoexpression of Nrf2 was observed in both the cytoplasm and the nucleus of neoplastic cells from PAC. Nuclear staining for Nrf2 suggested its activation in the majority of the PAC cells, which was confirmed by the high expression of its target gene, Prx I. Quantification of MMP-2 secretion showed lower levels in PAC cell cultures when compared to OSCC cell cultures (p < 0.05). In conclusion, although Nrf2 overexpression has been frequently associated with high-grade malignancies, such relationship is not infallible and, in fact, the opposite may occur in low-grade tumors, such as PAC of minor salivary glands.

Nonequilibrium localization and the interplay between disorder and interactions.

We study the nonequilibrium interplay between disorder and interactions in a closed quantum system. We base our analysis on the notion of dynamical state-space localization, calculated via the Loschmidt echo. Although real-space and state-space localization are independent concepts in general, we show that both perspectives may be directly connected through a specific choice of initial states, namely, maximally localized states (ML-states). We show numerically that in the noninteracting case the average echo is found to be monotonically increasing with increasing disorder; these results are in agreement with an analytical evaluation in the single particle case in which the echo is found to be inversely proportional to the localization length. We also show that for interacting systems, the length scale under which equilibration may occur is upper bounded and such bound is smaller the greater the average echo of ML-states. When disorder and interactions, both being localization mechanisms, are simultaneously at play the echo features a non-monotonic behaviour indicating a non-trivial interplay of the two processes. This interplay induces delocalization of the dynamics which is accompanied by delocalization in real-space. This non-monotonic behaviour is also present in the effective integrability which we show by evaluating the gap statistics.

Body stature as a risk factor for diabetic sensory neuropathy.

Risk factors for vibratory perception threshold abnormalities were studied in 200 diabetic patients between the ages of 21 and 70 years and 62 control subjects of similar age. Vibratory perception (measured with the Biothesiometer) was absent over one or both halluces in 18 percent of the patients. In a stepwise multiple logistic regression analysis, height was the variable most strongly associated with absent vibratory perception (coefficient +/- SE, 0.501 +/- 0.097/inch; p less than 0.0001). Duration of diabetes (p less than 0.001), age (p less than 0.05), and ethanol use (p less than 0.05) were also associated. The prevalence of absent vibratory perception in the lower, middle, and upper thirds of the height distribution was 0.05, 0.08, and 0.40, respectively. Among the control subjects, there was no association of vibratory perception with either height or ethanol use. These data strongly suggest that body stature is a major risk factor for diabetic sensory neuropathy.

Clear-cell ameloblastoma (clear-cell odontogenic carcinoma): report of a case.

Clear-cell ameloblastoma (clear-cell odontogenic carcinoma) is an uncommon odontogenic epithelial neoplasm. We report a case of a well-circumscribed 2 cm radiolucent lesion of the anterior mandible in a 30-year-old woman; this tumor was curetted. The first recurrence (at 5-year follow-up) was treated by aggressive curettage, and in the second recurrence a block resection was performed. However, 2 years after the resection was performed, the tumor recurred for a third time as an extraosseous gingival tumor, and 6 months later a recurrence was noted involving only alveolar mucosa.

Peripheral dentinogenic ghost-cell tumor: a case report.

The dentinogenic ghost-cell tumor is a rare solid variant of the calcifying odontogenic cyst. Few peripheral cases of this tumor with clinical and radiographic documentation have been reported. A case of peripheral dentinogenic ghost-cell tumor is presented and the literature is reviewed.

Tuberculosis of the oral cavity: a case report.

Tuberculosis of the oral mucosa was associated with pulmonary tuberculosis in a 38-year-old white man. The patient presented with multiple oral ulcerations with an irregular periphery and a granular vegetative fundus. The oral lesions antedated the findings of primary pulmonary tuberculosis, and the diagnosis was initially established histologically. Through the differential diagnosis of oral ulcerations, the dentist can play a role in the early detection of tuberculosis.

Oral squamous cell carcinoma: a retrospective study of 740 cases in a Brazilian population.

The purpose of this study was to evaluate, retrospectively, the profile of patients with oral squamous cell carcinoma. They were referred to two hospitals of Belo Horizonte (MG, Brazil) between 1986 and 1996. The medical records of 740 patients presenting oral squamous cell carcinoma were reviewed in detail. The TNM classification and staging, age, gender, race, occupation, and site of the primary tumor were recorded. The male-to-female ratio was 4.8:1. The mean age was 58.6 years. Most of the patients were in their sixties and were farm workers. The tumors were found principally on the tongue. There was a close relationship between some habits (tobacco and alcohol consumption) and the development of oral squamous cell carcinoma. Most of the patients sought medical care in the first year, even though almost half of them had lesions in stage T4. The identification of the characteristics of this specific population might reflect either accomplishments or problems in oral cancer control and can enable the development of a primary prevention program for oral squamous cell carcinoma.