Examinando por Autor "Niklander, Sven E."

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    Analysis of the Anatomical and Dimensional Variations of the Nasopalatine Canal by Cone Beam Computed Tomography
    (Universidad de la Frontera, 2023-06) Godoy, Iván E.; Valenzuela, Kimberly A.; Arce, Cecilia P.; Arqueros, Marcelo R.; Rodríguez, Macarena C.; Niklander, Sven E.; Meléndez, Patricio A.
    Anatomical knowledge of the nasopalatine canal (PNC) is essential for performing surgeries in the anterior sector of the maxilla and thus anticipating possible complications. The objective of this work is to evaluate and determine the anatomical and dimensional variations of the CNP according to sex, age and dental status. This cross-sectional study analyzed a total of 251 CBCT images obtained from the database of the Oral and Maxillofacial Imaging Service of the Faculty of Dentistry of the Andrés Bello University, Viña del Mar, Chile. To evaluate the statistical association between CNP variations with sex, age and dental status, the Student's T test, chi-square and ANOVA (p<0.5) were performed. The CNP showed variability in terms of morphology and dimensions. The most predominant shape of the PNC was cylindrical (65.33 %) and the most frequent shape of the canal curvature in the sagittal plane was straight inclined (54.98 %). The mean length was 10.92 ± 2.82 mm, being greater in men (p<0.01). The most frequent anatomical variation in the coronal plane was the single channel type (57.76 %). The effect of sex on the distance between the anterior wall of the PNC and the buccal crest of the maxilla was not significant (p>0.05). In addition, a significant difference was detected between the dental state and the dimension of the vestibular table in relation to the CNP (p<0.01). CNP variations should be considered to avoid potential complications during surgical procedures. © 2023, Universidad de la Frontera. All rights reserved.
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    The role of icIL-1RA in keratinocyte senescence and development of the senescence-associated secretory phenotype
    (Company of Biologists Ltd, 2021-02) Niklander, Sven E.; Crane, Hannah L.; Darda, Lav; Lambert, Daniel W.; Hunter, Keith D.
    There is compelling evidence that senescent cells, through the senescence-associated secretory phenotype (SASP), can promote malignant transformation and invasion. Interleukin-1 (IL-1) is a key mediator of this cytokine network, but the control of its activity in the senescence programme has not been elucidated. IL-1 signalling is regulated by IL-1RA, which has four variants. Here, we show that expression of intracellular IL-1RA type 1 (icIL-1RA1), which competitively inhibits binding of IL-1 to its receptor, is progressively lost during oral carcinogenesis ex vivo and that the pattern of expression is associated with keratinocyte replicative fate in vitro. We demonstrate that icIL-1RA1 is an important regulator of the SASP in mortal cells, as CRISPR/Cas9-mediated icIL-1RA1 knockdown in normal and mortal dysplastic oral keratinocytes is followed by increased IL-6 and IL-8 secretion, and rapid senescence following release from RhoA-activated kinase inhibition. Thus, we suggest that downregulation of icIL-1RA1 in early stages of the carcinogenesis process can enable the development of a premature and deregulated SASP, creating a pro-inflammatory state in which cancer is more likely to arise.