Browsing by Subject "Cellular distribution"

Now showing 1 - 4 of 4

Open Access
Attributed relational graphs for cell nucleus segmentation in fluorescence microscopy images
(IEEE, 2013) Arslan, S.; Ersahin, T.; Cetin-Atalay, R.; Gunduz-Demir, C.
More rapid and accurate high-throughput screening in molecular cellular biology research has become possible with the development of automated microscopy imaging, for which cell nucleus segmentation commonly constitutes the core step. Although several promising methods exist for segmenting the nuclei of monolayer isolated and less-confluent cells, it still remains an open problem to segment the nuclei of more-confluent cells, which tend to grow in overlayers. To address this problem, we propose a new model-based nucleus segmentation algorithm. This algorithm models how a human locates a nucleus by identifying the nucleus boundaries and piecing them together. In this algorithm, we define four types of primitives to represent nucleus boundaries at different orientations and construct an attributed relational graph on the primitives to represent their spatial relations. Then, we reduce the nucleus identification problem to finding predefined structural patterns in the constructed graph and also use the primitives in region growing to delineate the nucleus borders. Working with fluorescence microscopy images, our experiments demonstrate that the proposed algorithm identifies nuclei better than previous nucleus segmentation algorithms. © 2012 IEEE.
Open Access
Biological properties of extracellular vesicles and their physiological functions
(Taylor & Francis, 2015) Yáñez-Mó, M.; Siljander, P. R. M.; Andreu, Z.; Zavec, A. B.; Borràs, F. E.; Buzas, E. I.; Buzas, K.; Casal, E.; Cappello, F.; Carvalho, J.; Colás, E.; Cordeiro-Da, S. A.; Fais, S.; Falcon-Perez, J. M.; Ghobrial, I. M.; Giebel, B.; Gimona, M.; Graner, M.; Gursel, I.; Gursel, M.; Heegaard, N. H. H.; Hendrix, A.; Kierulf, P.; Kokubun, K.; Kosanovic, M.; Kralj-Iglic, V.; Krämer-Albers, E. M.; Laitinen, S.; Lässer, C.; Lener, T.; Ligeti, E.; Line, A.; Lipps, G.; Llorente, A.; Lötvall, J.; Manček-Keber, M.; Marcilla, A.; Mittelbrunn, M.; Nazarenko, I.; Nolte-'t Hoen, E. N. M.; Nyman, T. A.; O'Driscoll, L.; Olivan, M.; Oliveira, C.; Pállinger, E.; Del Portillo, H. A.; Reventós, J.; Rigau, M.; Rohde, E.; Sammar, M.; Sánchez-Madrid, F.; Santarém, N.; Schallmoser, K.; Ostenfeld, M. S.; Stoorvogel, W.; Stukelj, R.; Grein V. D. S.G.; Helena,ü V. M.; Wauben, M. H. M.; De Wever, O.
In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells.While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system.
Open Access
Chemical and topographical modification of PHBV surface to promote osteoblast alignment and confinement
(John Wiley & Sons, Inc., 2008) Kenar, H.; Kocabas, A.; Aydınlı, Atilla; Hasirci, V.
Proper cell attachment and distribution, and thus stronger association in vivo between a bone implant and native tissue will improve the success of the implant. In this study, the aim was to achieve promotion of attachment and uniform distribution of rat mesenchymal stem cell-derived osteoblasts by introducing chemical and topographical cues on poly(3-hydroxybutyrate-co-3- hydroxyvalerate) (PHBV) film surfaces. As the chemical cues, either alkaline phosphatase was covalently immobilized on the film surface to induce deposition of calcium phosphate minerals or fibrinogen was adsorbed to improve cell adhesion. Microgrooves and micropits were introduced on the film surface by negative replication of micropatterned Si wafers. Both chemical cues improved cell attachment and even distribution on the PHBV films, but Fb was more effective especially when combined with the micropatterns. Cell alignment (<10° deviation angle) parallel to chemically modified microgrooves (1, 3, or 8 μm groove width) and on 10 μm-thick Fb lines printed on the unpatterned films was achieved. The cells on unpatterned and 5 μm-deep micropitted films were distributed and oriented randomly. Results of this study proved that microtopographies on PHBV can improve osseointegration when combined with chemical cues, and that microgrooves and cell adhesive protein lines on PHBV can guide selective osteoblast adhesion and alignment.
Open Access
Nuclear exclusion of p33ING1b tumor suppressor protein: explored in HCC cells using a new highly specific antibody
(Mary Ann Liebert, Inc, 2009) Sayan, B.; Emre, N. C. T.; Irmak, M. B.; Ozturk, M.; Cetin Atalay, R.
Mouse monoclonal antibodies (MAb) were generated against p33ING1b tumor suppressor protein. 15B9 MAb was highly specific in recognizing a single protein band of ∼33 kDa endogenous p33ING1b protein from HCC cell lines and normal liver tissue by Western blot analysis and by immunoprecipitation. Although p33ING1b mutations are rarely observed in cancer, differential subcellular distribution and nuclear exclusion of p33ING1b were reported in different cancer types. Therefore we analyzed the expression and subcellular localization of p33ING1b in HCC cell lines using 15B9 MAb. So far, p33ING1b mutations or differential subcellular localization are not reported in HCC. In this study, by indirect immunofluorescence using MAb 15B9, we demonstrate that nuclear localization of p33ING1b was highly correlated with well-differentiated HCC cell lines whereas poorly differentiated HCC cells have nuclear exclusion of the protein. Moreover no association was observed between differential subcellular localization of p33ING1b and p53 mutation status of HCC cell lines. Hence our newly produced MAb 15B9 can be used for studying cellular activities of p33ING1b under normal and cancerous conditions. © Copyright 2009, Mary Ann Liebert, Inc.