Search Results (5)

Phagocytosis (and endocytosis) is an unusual cellular process that results in the formation of a novel subcellular organelle, the phagosome. This phagosome contains not only the internalised target of phagocytosis but also the external medium, creating a new border between extracellular and intracellular environments. The boundary at the plasma membrane is, of course, tightly controlled and exploited in ionic cell signalling events. Although there has been much work on the control of phagocytosis by ions, notably, Ca²⁺ ions influxing across the plasma membrane, increasing our understanding of the mechanism enormously, very little work has been done exploring the phagosome/cytosol boundary. In this paper, we explored the changes in the intra-phagosomal Ca²⁺ ion content that occur during phagocytosis and phagosome formation in human neutrophils. Measuring Ca²⁺ ion concentration in the phagosome is potentially prone to artefacts as the intra-phagosomal environment experiences changes in pH and oxidation. However, by excluding such artefacts, we conclude that there are open Ca²⁺ channels on the phagosome that allow Ca²⁺ ions to “drain” into the surrounding cytosol. This conclusion was confirmed by monitoring the translocation of the intracellularly expressed YFP-tagged C2 domain of PKC-γ. This approach marked regions of membrane at which Ca²⁺ influx occurred, the earliest being the phagocytic cup, and then the whole cell. This paper therefore presents data that have novel implications for understanding phagocytic Ca²⁺ signalling events, such as peri-phagosomal Ca²⁺ hotspots, and other phenomena. Full article

This article argues that the transformations of the popular, which began in Europe around 1800 and introduced the powerful distinction between low culture and high culture, have established a competitive distinction between the popular and the non-popular that has become dominant over the course of the 20th century. As a result, the popular is no longer either the culture of the ‘lower classes’ or the inclusion of the ‘people’ in the service of higher goals. The popular today is hardly the object of desired transgressions (Leslie Fiedler’s “cross the border, close the gap”) or an expression of felt or feared “massification” or “flattening”. Rather, being popular now means getting noticed by many. Popularity is measured as well as staged, as rankings and charts provide information on what is popular while vying for popularity themselves. These quantifying formats do not speak to the quality or originality of the popular, only to its evident success across different scales of evaluation. People do not buy good products, they buy popular ones; they do not listen to the best music, but to popular music; they do not share, like, or retweet important, but popular news. Even the ‘unpopular’ can be popular: a despised politician, a hated jingle, an unpopular measure. The popular modifies whatever it affords with attention. Its quantitatively and hierarchically comparative terms (‘bestseller,’ ‘outperformer,’ ‘high score,’ ‘viral’) generate valences that do not inhere in the objects themselves. Conversely, the non-popular, which does not find any measurable resonance in these terms, risks being dismissed as irrelevant or worthless simply because it does not appear in any rankings or ratings. This can be observed particularly with artefacts whose relevance as part of high culture may be taken for granted even when they do not achieve mass resonance. The purpose of this article is to outline a theory of the popular that does justice to these developments by identifying two decisive transformations: 1. the popularization of quantifying methods to measure attention in popular culture around 1950; 2. the popularization of the internet around 2000, whereby the question of what can and cannot become popular is partially removed from the gatekeepers of the established mass media, educational institutions, and cultural elites and is increasingly decided via social media. Full article

Rheumatoid arthritis is a chronic inflammatory disease characterized by the development of osseous and cartilaginous damage. The correct differentiation between a true erosion and other entities—then often called “pseudoerosions”—is essential to avoid misdiagnosing rheumatoid arthritis and to correctly interpret the progress of the disease. The aims of this systematic review were as follows: to create a definition and delineation of the term “pseudoerosion”, to point out morphological pitfalls in the interpretation of images, and to report on difficulties arising from choosing different imaging modalities. A systematic review on bone erosions in rheumatoid arthritis was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The following search terms were applied in PubMed and Scopus: “rheumatoid arthritis”, “bone erosion”, “ultrasonography”, “radiography”, “computed tomography” and “magnetic resonance imaging”. Appropriate exclusion criteria were defined. The systematic review registration number is 138826. The search resulted ultimately in a final number of 25 papers. All indications for morphological pitfalls and difficulties utilizing imaging modalities were recorded and summarized. A pseudoerosion is more than just a negative definition of an erosion; it can be anatomic (e.g., a normal osseous concavity) or artefact-related (i.e., an artificial interruption of the calcified zones). It can be classified according to their configuration, shape, content, and can be described specifically with an anatomical term. “Calcified zone” is a term to describe the deep components of the subchondral, subligamentous and subtendinous bone, and may be applied for all non-cancellous borders of a bone, thus representing a third type of the bone matrix beside the cortical and the trabecular bone. Full article

Background and Objectives: There are only a few studies regarding gut subepithelial telocytes (TCs). The telopodes, namely peculiar TCs’ prolongations described on two-dimensional cuts, are not enough to differentiate this specific cell type. Subepithelial TCs were associated with the intestinal stem niche but a proper differential diagnosis with lymphatic endothelial cells (LECs) was not performed. In this study, we will also critically review studies suggesting that distinctive TCs could be positioned within the lamina propria. Materials and Methods: We performed an immunohistochemical study of human gastric mucosa to test the expression of D2-40, the lymphatic marker, as well as that of CD31, CD34, CD44, CD117/c-kit, α-smooth muscle actin (α-SMA) and vimentin in the gastric subepithelial niche. Results: The results support the poorly investigated anatomy of intramural gastric lymphatics, with circumferential collectors located on both sides of the muscularis mucosae (mucosal and then submucosal) and myenteric collectors in the muscularis propria. We also found superficial epithelial prelymphatic channels bordered by D2-40+ but CD31–TC-like cells. Deep epithelial lymphatic collectors drain in collectors within the lamina propria. Blood endothelial cells expressed CD31, CD34, CD44, and vimentin. Conclusions: Therefore, the positive diagnosis of TC for subepithelial CD34+ cells should be regarded with caution, as they could also be artefacts, resulting from the two-dimensional examination of three dimensional structures, or as LECs. Lymphatic markers should be routinely used to discriminate TCs from LECs. Full article

The JPEG-XR encoding process utilizes two types of transform operations: Photo Overlap Transform (POT) and Photo Core Transform (PCT). Using the Device Porting Kit (DPK) provided by Microsoft, we performed encoding and decoding processes on JPEG XR images. It was discovered that when the quantization parameter is >1-lossy compression conditions, the resulting image displays chequerboard block artefacts, border artefacts and corner artefacts. These artefacts are due to the nonlinearity of transforms used by JPEG-XR. Typically, it is not so visible; however, it can cause problems while copying and scanning applications, as it shows nonlinear transforms when the source and the target of the image have different configurations. Hence, it is important for document image processing pipelines to take such artefacts into account. Additionally, these artefacts are most problematic for high-quality settings and appear more visible at high compression ratios. In this paper, we analyse the cause of the above artefacts. It was found that the main problem lies in the step of POT and quantization. To solve this problem, the use of a “uniform matrix” is proposed. After POT (encoding) and before inverse POT (decoding), an extra step is added to multiply this uniform matrix. Results suggest that it is an easy and effective way to decrease chequerboard, border and corner artefacts, thereby improving the image quality of lossy encoding JPEG XR than the original DPK program with no increased calculation complexity or file size. Full article