133,842 research outputs found
Interleukin-21 controls inflammatory pathways in IBD
No full textIn both Crohn’s disease (CD) and ulcerative colitis (UC), the major forms of inflammatory bowel diseases (IBD) in humans, the pathologic process consists of an aberrant local immune response to components of the bacterial microflora, due to abnormally strong effector cell activity that is poorly controlled by counter-regulatory mechanisms. There is also evidence that mucosal immune cells actively interact with non-immune cells to promote tissue damage, and that cytokines are essential mediators of this cross-talk. Interleukin-21 (IL-21), the latest member of the common gamma-chain-dependent cytokine family, is a product of activated CD4+ T cells and natural killer T cells. IL-21 is produced in excess in CD tissue, where it helps sustain the ongoing Th1 inflammation. High IL-21 production occurs also in the inflamed colon of most patients with UC, a disease that is not associated with a marked Th1 cell response. This suggests that, in the gut, IL-21 can modulate additional inflammatory pathways other than enhancing Th1 cell immunity. Indeed, IL-21 enhances the secretion of extracellular matrix degrading enzymes by fibroblasts, and of the T cell chemoattractant, MIP-3alpha, by epithelial cells. These data collectively indicate that IL-21 is a mediator of the chronic inflammatory response in CD and UC, and suggest that IL-21 may be an emerging therapeutic target in IBD
Fatores associados ao diagnóstico citológico de malignidade em punção aspirativa por agulha fina nos nódulos de mama.
No full textTrabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Departamento de Tocoginecologia
Novel poly(l-lactide)/poly(d-lactide)/poly(tetrahydrofuran) multiblock copolymers with a controlled architecture: Synthesis and characterization
No full textNovel poly(L-lactide) (PLLA)/poly(D-lactide) (PDLA)/poly(tetrahydrofuran) (PTHF) multiblock copolymers with designed molecular structure were synthesized by a two-stage procedure. Well-defined PDLA-PLLA-PTHF-PLLA-PDLA pentablock copolymers were prepared by sequential ring opening polymerization of L- and D-lactides starting from PTHF glycol, with the length of the (equimolar) PLLA and PDLA blocks being varied. Then, these dihydroxyl-terminated pentamers were transformed into multiblock copolymers by melt chain-extension with hexamethylene diisocyanate-being the first time that the coupling of pentablock units is reported. The successful formation of macromolecular chains with a multiblock and well-defined architecture was demonstrated by 1H NMR spectroscopy. The thermal properties and structuring of the resulting materials were investigated by means of DSC and WAXD measurements and DMA analysis. Stereocomplexation was found to be promoted during solution and melt crystallization. This approach affords materials combining the high rigidity and strength (other than improved thermal resistance) of the hard stereocomplex crystallites with the flexibility imparted by the soft block, whereby their properties can be finely tailored through the composition of the basic pentablock units without limitations on the final molecular weight. The adopted reaction conditions make this process highly appealing in view of the possibility to perform it in extruder
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
NANOSTRUCTURE SURFACE INTERACTION WITH POLYMERS: The key factor in nanocomposite preparation
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