1,721,002 research outputs found
EFFECT OF EXPERIMENTAL FEBRILE SEIZURES ON DENDRITOGENESIS OF NEWBORN HIPPOCAMPAL DENTATE GRANULE CELLS
No full textEFFECT OF EXPERIMENTAL FEBRILE SEIZURES ON DENDRITOGENESIS OF NEWBORN HIPPOCAMPAL DENTATE GRANULE CELLS
No full textUnsupervised Machine Learning‐Based Clustering of Nanosized Fluorescent Extracellular Vesicles
No full textExtracellular vesicles (EV) are biological nanoparticles that play an important role in cell-to-cell communication. The phenotypic profile of EV populations is a promising reporter of disease, with direct clinical diagnostic relevance. Yet, robust methods for quantifying the biomarker content of EV have been critically lacking, and require a single-particle approach due to their inherent heterogeneous nature. Here, multicolor single-molecule burst analysis microscopy is used to detect multiple biomarkers present on single EV. The authors classify the recorded signals and apply the machine learning-based t-distributed stochastic neighbor embedding algorithm to cluster the resulting multidimensional data. As a proof of principle, the authors use the method to assess both the purity and the inflammatory status of EV, and compare cell culture and plasma-derived EV isolated via different purification methods. This methodology is then applied to identify intercellular adhesion molecule-1 specific EV subgroups released by inflamed endothelial cells, and to prove that apolipoprotein-a1 is an excellent marker to identify the typical lipoprotein contamination in plasma. This methodology can be widely applied on standard confocal microscopes, thereby allowing both standardized quality assessment of patient plasma EV preparations, and diagnostic profiling of multiple EV biomarkers in health and disease.The authors thank Veronique Vastmans and Iris Reniers for the technical assistance. S.K. was funded by Hasselt University. J.H. acknowledges funding by UH-BOF (BOF20TT06). The FWO-Hercules Foundation of Flanders (grant number R-7087), the Research Foundation Flanders (FWO, Herculesstichting) (Grant number G0H3716N) and the province of Limburg (Belgium) (tUL Impuls II) are acknowledged for funding the microscopy hardware. L.M. and B.H. acknowledge the funding by the EU/EFRO through the Interreg V Flanders-the Netherlands project Trans Tech Diagnostics (TTD) and grant number 2015N017047 of the province of Limburg.Hendrix, J; Hosseinkhani, B (corresponding author), Hasselt Univ, Biomed Res Inst BIOMED, Martelarenlaan 42, B-3500 Hasselt, Belgium ;
Hasselt Univ, Adv Opt Microscopy Ctr, Dynam Bioimaging Lab, B-3500 Hasselt, Belgium.
[email protected]; [email protected]
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The dynamic behavior of the glycine receptor in the plasma membrane. An exploratory study by ensemble averaging microfluorimetric methods
No full textDe glycinereceptor (GlyR) vervult een belangrijke rol in de snelle, inhibitorische neuronale signaaloverdracht in het centrale zenuwstelsel van vertebraten. De GlyR is een pentameer dat kan bestaan uit verschillende subeenheden (α1, α2, α3, α4, β). Clustering van de heteropentamere GlyR α1β ter hoogte van het postsynaptisch membraan is essentieel om de signaaloverdracht efficiënt uit te voeren. De regulatie van deze clustering werd lange tijd beschouwd als een statisch gegeven waarbij voornamelijk de endo- en exocytose van aggregaten van GlyRs bepalend werd geacht. Fluorescentiemicroscopie van de receptor in levende cellen heeft deze visie grondig veranderd
Ensemble and single particle fluorimetric techniques in concerted action to study the diffusion and aggregation of the glycine receptor α3 isoforms in the cell plasma membrane
No full textAbstractThe spatio-temporal membrane behavior of glycine receptors (GlyRs) is known to be of influence on receptor homeostasis and functionality. In this work, an elaborate fluorimetric strategy was applied to study the GlyR α3K and L isoforms. Previously established differential clustering, desensitization and synaptic localization of these isoforms imply that membrane behavior is crucial in determining GlyR α3 physiology. Therefore diffusion and aggregation of homomeric α3 isoform-containing GlyRs were studied in HEK 293 cells. A unique combination of multiple diffraction-limited ensemble average methods and subdiffraction single particle techniques was used in order to achieve an integrated view of receptor properties. Static measurements of aggregation were performed with image correlation spectroscopy (ICS) and, single particle based, direct stochastic optical reconstruction microscopy (dSTORM). Receptor diffusion was measured by means of raster image correlation spectroscopy (RICS), temporal image correlation spectroscopy (TICS), fluorescence recovery after photobleaching (FRAP) and single particle tracking (SPT). The results show a significant difference in diffusion coefficient and cluster size between the isoforms. This reveals a positive correlation between desensitization and diffusion and disproves the notion that receptor aggregation is a universal mechanism for accelerated desensitization. The difference in diffusion coefficient between the clustering GlyR α3L and the non-clustering GlyR α3K cannot be explained by normal diffusion. SPT measurements indicate that the α3L receptors undergo transient trapping and directed motion, while the GlyR α3K displays mild hindered diffusion. These findings are suggestive of differential molecular interaction of the isoforms after incorporation in the membrane
Cell viability on functionalized diamond surfaces : towards non-invasive monitoring of cell characteristics
No full textIn this report both qualitative and quantitative results on cell viability of Chinese hamster ovary (CHO) cells cultured on bare, well-characterized nano- and microcrystalline diamond surfaces, either hydrogen or oxygen terminated, are presented and discussed. CHO cells stably transfected with homomeric embryonic a2 glycine receptors are chosen since they offer a simplified cellular model. A systematic investigation of the viability is justified since earlier published reports are limited to more elaborate coated, single-crystal diamond surfaces.
Qualitative information was derived from visual inspection of the CHO cells on the microwave plasma-enhanced chemical vapor deposited (MPE-CVD) thin diamond films - deposited on silicon - using both scanning electron microscopy and optical reflection microscopy. Compared with control glass substrates, no apparent difference existed either in cell morphology or in cell density on all substrates tested.
In order to quantify these observations, other methods were applied. These consisted of different biochemical assays: the MTT cell proliferation assay (testing for proliferation and
metabolic activity), the Bradford assay (total protein content), the [3H]-thymidine cell
proliferation assay (proliferation) and flow cytometry (living/necrotic/apoptotic cells).
Consistent with the results obtained from visual inspection, no significant differences were found using one-way ANOVA. Yet, after 7 days post seeding, the MTT result did indicate significant differences between the tested substrates. However, this is not yet reproduced.
Based on these results, it can reasonably be conclude that, at least for the CHO cells used,
bare nano- and microcrystalline diamond surfaces poorly affect, if at all, the growth and the viability of cultured cells.
As a result, the diamond surfaces which are easiest to grow and to modify, with the best characteristics and the best shelf life, can be applied as substrate to develop non-invasive interfaces between biological cells on the one hand, and microelectronics on the other
Cell viability on functionalized diamond surfaces : towards non-invasive monitoring of cell characteristics
No full textIn this report both qualitative and quantitative results on cell viability of Chinese hamster ovary (CHO) cells cultured on bare, well-characterized nano- and microcrystalline diamond surfaces, either hydrogen or oxygen terminated, are presented and discussed. CHO cells stably transfected with homomeric embryonic a2 glycine receptors are chosen since they offer a simplified cellular model. A systematic investigation of the viability is justified since earlier published reports are limited to more elaborate coated, single-crystal diamond surfaces.
Qualitative information was derived from visual inspection of the CHO cells on the microwave plasma-enhanced chemical vapor deposited (MPE-CVD) thin diamond films - deposited on silicon - using both scanning electron microscopy and optical reflection microscopy. Compared with control glass substrates, no apparent difference existed either in cell morphology or in cell density on all substrates tested.
In order to quantify these observations, other methods were applied. These consisted of different biochemical assays: the MTT cell proliferation assay (testing for proliferation and
metabolic activity), the Bradford assay (total protein content), the [3H]-thymidine cell
proliferation assay (proliferation) and flow cytometry (living/necrotic/apoptotic cells).
Consistent with the results obtained from visual inspection, no significant differences were found using one-way ANOVA. Yet, after 7 days post seeding, the MTT result did indicate significant differences between the tested substrates. However, this is not yet reproduced.
Based on these results, it can reasonably be conclude that, at least for the CHO cells used,
bare nano- and microcrystalline diamond surfaces poorly affect, if at all, the growth and the viability of cultured cells.
As a result, the diamond surfaces which are easiest to grow and to modify, with the best characteristics and the best shelf life, can be applied as substrate to develop non-invasive interfaces between biological cells on the one hand, and microelectronics on the other
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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