Examinando por Autor "Niklander, Sven"
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Ítem Alveolar soft-part sarcoma of the masseter and mandibular ramus: Report of a case and review of the literature(Association for Dental Sciences of the Republic of China, 2018-03) Martínez, René; Niklander, Sven; Deichler, Javiera; Leissner, Oliver; Seguel, Heraldo; Esguep, AlfredoAlveolar soft-part sarcomas are clinically and morphologically distinct soft-tissue sarcomas, with an unknown histogenesis. When the tumors affect the region of the head and neck, they are often located in the orbit and tongue. We report a case of an alveolar soft-part sarcoma in the left masseter of a 28-year-old female. The patient had chronic pain and paresthesia of her left lower lip. Panoramic radiography and computed tomography showed a well-delimited radiolucent mass in the left ramus. An incisional biopsy was performed, and the sample submitted for histopathological study. The tumor showed positive periodic acid-Schiff diastase-resistant granules. Immunohistochemically, the tumor cells were diffusely positive for myoglobin, and focally positive for actin and desmin. © 2018Ítem Hypoxia-inducible factor-1α at the invasive tumor front in oral squamous cell carcinoma(Baishideng Publishing Group Inc, 0025) Silveira, Felipe Martins; Schuch, Lauren Frenzel; Pereira-Prado, Vanesa; Molina-Frechero, Nelly; Lopez-Verdin, Sandra; Gómez Palacio-Gastélum, Marcelo; Arocena, Miguel; Niklander, Sven; Sicco, Estefania; Bologna-Molina, RonellBACKGROUND Hypoxia in oral cancer promotes tumoral invasion by inducing epithelial-mesenchymal transition, leading to aggressive tumor progression. AIM To characterize the expression of hypoxia-inducible factor 1-alpha (HIF-1α) at the invasive tumor front (ITF) in comparison to tumor islands (TI) in oral squamous cell carcinoma (OSCC) and to explore its relationship with E-cadherin and Vimentin expression. METHODS Thirty-eight cases of OSCC and five cases of normal oral mucosa (NOM) were included in this study. The ITF was identified based on the region and immune expression of AE1/AE3. Immunohistochemistry was performed to assess the expression of HIF-1α, Vimentin, and E-cadherin. The immunostaining was analyzed using an immunoreactive score, and the results were illustrated using immunofluorescence. RESULTS HIF-1α expression was significantly higher in the TI region compared to the ITF region (P = 0.0134). Additionally, a significant difference was observed between TI and NOM (P = 0.0115). In the ITF regions, HIF-1α expression showed a significant correlation with Vimentin expression, with higher levels of HIF-1α associated with increased Vimentin expression (P = 0.017). CONCLUSION Based on the results of this study, HIF-1α appears to play a distinct role in OSCC tumor progression, underscoring the importance of exploring hypoxia-driven changes in cellular phenotype at the ITF of OSCC. Further research is needed to better understand their impact on OSCC prognosis. ©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.Ítem Pitfalls in odontogenic lesions and tumours: a practical guide(Elsevier Ltd, 2020-12) Hunter, Keith D; Niklander, SvenLesions arising from odontogenic tissues of the jaws vary from very common to very rare. Some, such as radicular cysts, form a routine part of the diagnostic workload for histopathologists who report specimens from the head and neck, but many other lesions are rarely seen and can cause significant diagnostic difficulty for the non-specialist. These issues are compounded by the vagaries of dental disease (and terminology used by dentists and oral surgeons) and issues in the interpretation of radiographic images, which can be crucial to making a correct diagnosis. In this review article, we will discuss a number of areas of diagnostic difficulty, largely based on the authors experience in receiving tertiary referrals. This will focus on practical advice to help avoid the pitfalls in the diagnosis of odontogenic lesions.Ítem Relationship Between the Maxillary Sinus and Apices of Posterior-Superior Teeth Using Cone Beam Computed Tomography(Universidad de la Frontera, 2023-04) Rodríguez, Macarena; Richa, Roxana; Valenzuela, Juan Jose; Niklander, SvenKnowledge of the relationship between the maxillary sinus and the apices of the upper posterior teeth is crucial to avoid complications when considering different treatments. A descriptive cross-sectional study was carried out, with a convenience sample of 383 images of upper posterior teeth roots, obtained by means of cone beam computed tomography (CBCT) from a radiological center in Viña del Mar, Chile. Each root was classified according to its vertical relationship with the sinus into 4 categories (0: apex is not in contact with the lower contour of the sinus; 1: apex is in contact with the sinus; 2: apex laterally to the sinus; 3: apex protrudes in sinus). In addition, its distance was measured in mm. The data were analyzed with descriptive statistics. The tooth farthest from the maxillary sinus was the maxillary first premolar (4.2 mm), followed by the maxillary second premolar (1 mm). In the upper first molar, the most distant root was the mesiobuccal (MV) 1mm, followed by the distobuccal root (DV) 0.6mm and the palatal root (P)-1mm. In the upper second molar, the furthest root was P 0.4mm, then DV 0.3mm, and MV-0.11mm. In reference to the categories, it was observed that most of the roots are far from the sinus, with the P root of the first upper molar and the MV root of the second upper molar being the most protruding (42 % and 26 % respectively). The first premolar is the posterior maxillary tooth that is furthest from the maxillary sinus and as one advances posteriorly there is a tendency to decrease the distance between the apices and the maxillary sinus. © 2023, Universidad de la Frontera. All rights reserved.Ítem Vascular endothelial growth factor: A translational view in oral non-communicable diseases(Biomolecules, 2021-01) Niklander, Sven; Bordagaray, María José; Fernández, Alejandra; Hernández, MarcelaVascular endothelial growth factors (VEGFs) are vital regulators of angiogenesis that are expressed in response to soluble mediators, such as cytokines and growth factors. Their physio-logic functions include blood vessel formation, regulation of vascular permeability, stem cell and monocyte/macrophage recruitment and maintenance of bone homeostasis and repair. In addition, angiogenesis plays a pivotal role in chronic pathologic conditions, such as tumorigenesis, inflammatory immune diseases and bone loss. According to their prevalence, morbidity and mortality, inflammatory diseases affecting periodontal tissues and oral cancer are relevant non-communicable diseases. Whereas oral squamous cell carcinoma (OSCC) is considered one of the most common cancers worldwide, destructive inflammatory periodontal diseases, on the other hand, are amongst the most prevalent chronic inflammatory conditions affecting humans and also represent the main cause of tooth loss in adults. In the recent years, while knowledge regarding the role of VEGF signaling in common oral diseases is expanding, new potential translational applications emerge. In the present narrative review we aim to explore the role of VEGF signaling in oral cancer and destructive periodontal inflammatory diseases, with emphasis in its translational applications as potential biomarkers and therapeutic targets. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.