40 research outputs found

    Bacterial adherence to mucosal epithelium in the upper airways has less significance than believed

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    BACKGROUND: Bacterial adherence to the upper airway epithelium is considered to be an important phenomenon in the pathogenesis of infections. However, the evidence for the hypothesis that bacterial adherence to mucosal epithelial cells has significance for pathogenesis of mucosal infections is based on studies using indirect techniques. We could find no biopsy studies with direct ocular observations of significant numbers of bacteria adhering to upper airway mucosal epithelial cells either in health or during disease. RESULTS: We studied specimens from healthy and infected tonsillar epithelium and specimens from the soft palate epithelium obtained by surgery. The specimens were examined by TEM. In the vast majority of specimens, we found no bacteria adhering to the epithelial cells in the mucosal line regardless of whether the patient was infected or not. Bacteria adhering to shed epithelial cells were seen in higher numbers. Furthermore, as bacteria are small compared to epithelial cells, we calculated the risk of overlooking every adhered bacteria in a section if bacterial adherence was such a significant phenomenon as earlier suggested. We found this risk to be very small. CONCLUSION: We conclude that bacterial adherence to mucosal surface epithelial cells is not a significant phenomenon, either in healthy mucosa in the upper airways or during infection. This is also in line with our earlier results, where we have shown that the site for the infectious process in pharyngotonsillitis is in the secretion on the tonsillar mucosal surface

    Laplacian Growth, Elliptic Growth, and Singularities of the Schwarz Potential

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    The Schwarz function has played an elegant role in understanding and in generating new examples of exact solutions to the Laplacian growth (or "Hele- Shaw") problem in the plane. The guiding principle in this connection is the fact that "non-physical" singularities in the "oil domain" of the Schwarz function are stationary, and the "physical" singularities obey simple dynamics. We give an elementary proof that the same holds in any number of dimensions for the Schwarz potential, introduced by D. Khavinson and H. S. Shapiro [17] (1989). A generalization is also given for the so-called "elliptic growth" problem by defining a generalized Schwarz potential. New exact solutions are constructed, and we solve inverse problems of describing the driving singularities of a given flow. We demonstrate, by example, how \mathbb{C}^n - techniques can be used to locate the singularity set of the Schwarz potential. One of our methods is to prolong available local extension theorems by constructing "globalizing families". We make three conjectures in potential theory relating to our investigation

    IRAK4 gene polymorphism and odontogenic maxillary sinusitis

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    Objectives This study aimed to evaluate whether a specific interleukin-1 receptor-associated kinase-4 (IRAK4) gene polymorphism had any influence on the development of changes in maxillary sinus, particularly in the presence of etiological factors of dental origin.Materials and methods The study population included 153 Portuguese Caucasians that were selected from a database of 504 retrospectively analysed computed tomography (CT) scans. A genetic test was performed, and a model was created through logistic analysis and regression coefficients. The statistical methodologies included were the independent Chi test, Fisher's exact test, binary logistic regression and the receiver operating characteristic (ROC) curve.Results The estimated prevalence of IRAK4 gene polymorphism found in a Portuguese Caucasian population was 26.8 % (CI 95 %) [20.1, 34.7 %]. A model to predict the inflammatory response in the maxillary sinus in the presence etiological factors of dental origin was constructed. This model had the following as variables: previously diagnosed sinusitis, sinus pressure symptoms, cortical bone loss observed on CT, positive genetic test result and radiographic examination that revealed the roots of the teeth communication with the maxillary sinus, which are interpreted as risk factors.Conclusions The constructed model should be considered an initial clinical tool. The area under the ROC curve found, AUC=0.91, revealed that the model correctly predicts the outcome in 91.1 % of cases.info:eu-repo/semantics/publishedVersio

    Random Matrices in 2D, Laplacian Growth and Operator Theory

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    Since it was first applied to the study of nuclear interactions by Wigner and Dyson, almost 60 years ago, Random Matrix Theory (RMT) has developed into a field of its own within applied mathematics, and is now essential to many parts of theoretical physics, from condensed matter to high energy. The fundamental results obtained so far rely mostly on the theory of random matrices in one dimension (the dimensionality of the spectrum, or equilibrium probability density). In the last few years, this theory has been extended to the case where the spectrum is two-dimensional, or even fractal, with dimensions between 1 and 2. In this article, we review these recent developments and indicate some physical problems where the theory can be applied.Comment: 88 pages, 8 figure

    Neutrophils in mucosal secretion are functionally active

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    The leucocytes in the secretion on the tonsillar surface have been regarded as inactivated and dying cells with no essential function in the defence of the underlying mucosa. In recent studies, we showed that in acute tonsillitis there are very few, if any, bacteria in the parenchyma, whereas in the secretion on the tonsillar surface there are huge numbers of bacteria and neutrophils, and furthermore, extensive phagocytosis. The present study was performed to elucidate the functional capacity of the neutrophils in the secretion on the tonsillar surface. Secretion samples were taken from the tonsillar surface of healthy volunteers with an imprint technique which allows transfer of secretion from the mucosa to a glass slide with maintained topographic position of the cells. The capacity of the neutrophils to respond to chemotactic stimuli and to phagocytize and further process labelled yeast particles was studied in this in vitro system. The results show that the neutrophils in the secretion have the same properties as in tissue, and also when having arrived in the secretion they can identify and attack new prey
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