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Fluorescence Patterns (fluorescence + pattern)
Selected AbstractsSpecific dynamic and noninvasive labeling of pancreatic , cells in reporter miceGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 4 2005Ahmi Ben-Yehudah Abstract Noninvasive detection of differentiated cells is increasingly demanded for accurate and reliable assessments of both in vitro and in vivo experimental systems. Here we present an efficient, innovative approach for imaging the , cells of the pancreatic islets of Langerhans. The main physiologic function of , cells is glucose-stimulated insulin secretion. This function is facilitated through the synthesis and storage of insulin in secretory vesicles of , cells, which then release their contents when , cells are exposed to hyperglycemic conditions. To visualize , cells in vivo in the mouse, we used targeted mutagenesis techniques to construct a modified insulin II (InsII) gene allele, InsIIEGFP, that expresses a proinsulin-EGFP (enhanced green fluorescent protein) fusion peptide. The EGFP portion of this fusion is entirely within the C-peptide portion of the proinsulin peptide. This fusion protein is processed in , cells to insulin and EGFP-tagged C peptide, which are stored together in cytoplasmic secretory vesicles. The large amount of vesicular EGFP-tagged C peptide is evident as a characteristic robust and specific fluorescence pattern in the , cells of InsIIEGFP mice. This innovative method of visualizing , cells will be a useful tool in the study of both , cell physiology and the development of the endocrine cells of the pancreas.genesis 43:166,174, 2005. © 2005 Wiley-Liss, Inc. [source] Effect of freezing-thawing on the expression of mannose-ligand receptors on human spermatozoa: the impact on sperm capacitation and acrosome reactionANDROLOGIA, Issue 5 2001H. Yavetz Summary The aim of this study was to evaluate the change in the expression of mannose-ligand receptors following a freezing-thawing procedure, in order to assess its impact on sperm capacitation and acrosome reaction. Twenty semen samples were obtained from fertile donors. Sperm samples were divided into two equal volumes. One aliquot was cryopreserved and the other aliquot was incubated at 32°C. After 2 h the frozen sample was thawed and both samples were further incubated at 32°C to allow capacitation. Mannose receptors were examined following 4 and 22 h of incubation using a mannosylated-BSA-FITC probe. The expression of mannose-ligand receptors on the sperm plasma membrane was determined according to the fluorescence pattern: pattern I represents pre-capacitation, pattern II represents capacitated spermatozoa and pattern III represents acrosome-reacted spermatozoa. After 4 h incubation in capacitating medium, the percentages of patterns I, II and III were 90, 7 and 3% for fresh spermatozoa and 89, 8 and 3% for frozen-thawed spermatozoa, respectively (P>0.05). Following 22 h of incubation, the percentages of patterns I, II and III were 84, 11 and 5 for fresh spermatozoa and 83, 11 and 6% for frozen-thawed spermatozoa, respectively (not significant at P>0.05). The percentages of patterns II and III in fresh and frozen-thawed spermatozoa were increased by the same magnitude with longer incubation in the capacitating conditions. It was concluded that the freezing-thawing procedure for human spermatozoa does not affect the expression of mannose-ligand receptors and the dynamics of sperm pre-fertilization processes. [source] Effect of freezing,thawing on the expression of mannose-ligand receptors on human spermatozoa: the impact on sperm capacitation and acrosome reactionANDROLOGIA, Issue 5 2001H. Yavetz Summary., The aim of this study was to evaluate the change in the expression of mannose-ligand receptors following a freezing,thawing procedure, in order to assess its impact on sperm capacitation and acrosome reaction. Twenty semen samples were obtained from fertile donors. Sperm samples were divided into two equal volumes. One aliquot was cryopreserved and the other aliquot was incubated at 32 °C. After 2 h the frozen sample was thawed and both samples were further incubated at 32 °C to allow capacitation. Mannose receptors were examined following 4 and 22 h of incubation using a mannosylated-BSA-FITC probe. The expression of mannose-ligand receptors on the sperm plasma membrane was determined according to the fluorescence pattern: pattern I represents pre-capacitation, pattern II represents capacitated spermatozoa and pattern III represents acrosome-reacted spermatozoa. After 4 h incubation in capacitating medium, the percentages of patterns I, II and III were 90, 7 and 3% for fresh spermatozoa and 89, 8 and 3% for frozen,thawed spermatozoa, respectively (P > 0.05). Following 22 h of incubation, the percentages of patterns I, II and III were 84, 11 and 5 for fresh spermatozoa and 83, 11 and 6% for frozen,thawed spermatozoa, respectively (not significant at P > 0.05). The percentages of patterns II and III in fresh and frozen,thawed spermatozoa were increased by the same magnitude with longer incubation in the capacitating conditions. It was concluded that the freezing,thawing procedure for human spermatozoa does not affect the expression of mannose-ligand receptors and the dynamics of sperm pre-fertilization processes. [source] Fifty years of antineutrophil cytoplasmic antibodies (ANCA) testing: do we need to revise the international consensus statement on testing and reporting on ANCA?APMIS, Issue 2009JAN WILLEM COHEN TERVAERT During the first international workshop on antineutrophil cytoplasmic antibodies (ANCA), Copenhagen 25 and 26 January 1988, ANCA, as detected by the indirect immunofluorescence (IIF) technique, was extensively discussed. Cytoplasmic fluorescence pattern was found in patients with vasculitis. In contrast, perinuclear fluorescence pattern was found in vasculitis but also in many other inflammatory disorders. At the workshop, it was stated that IIF should be combined with an antigen-specific technique and capture and direct enzyme-linked immunosorbent assay techniques were discussed. In 1999/2003, an international consensus statement on testing and reporting on ANCA was published. For vasculitis, IIF was advocated as a screening assay, followed by an antigen-specific assay. In other non-vasculitic inflammatory diseases, only IIF on ethanol-fixed granulocytes was advocated. Recently, it was demonstrated that antigen-specific tests could be used as screening tests. Furthermore, it became clear that antigen-specific tests, in which antigens are directly coated to the solid phase, demonstrate highly variable sensitivities and specificities, whereas when capture or anchor technologies are used, more reproducible results are obtained. Based on these studies, we propose that the international consensus statement on ANCA should be revised. [source] Functionalized Siloles: Versatile Synthesis, Aggregation-Induced Emission, and Sensory and Device ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 6 2009Zhen Li Abstract The synthesis of functionalized siloles has been a challenge because of the incompatibility of polar functional groups with the reactive intermediates in the conventional protocols for silole synthesis. In this work, a synthetic route for silole functionalization is elaborated, through which a series of functionalized siloles are successfully prepared. Whereas light emissions of traditional luminophores are often quenched by aggregation, most of the functionalized siloles show an exactly opposite phenomenon of aggregation-induced emission (AIE). The siloles are nonemissive when dissolved in their good solvents but become highly luminescent when aggregated in their poor solvents or in the solid state. Manipulation of the aggregation,deaggregation processes of the siloles enables them to play two seemly antagonistic roles and work as both excellent quenchers and efficient emitters. The AIE effect endows the siloles with multifaceted functionalities, including fluorescence quenching, pH sensing, explosive detection, and biological probing. The sensing processes are very sensitive (with detection limit down to 0.1,ppm) and highly selective (with capability of discriminating among different kinds of ions, explosives, proteins, DNAs, and RNAs). The siloles also serve as active layers in the fabrication of electroluminescent devices and as photosensitive films in the generation of fluorescence patterns. [source] Confined displacement algorithm determines true and random colocalization in fluorescence microscopyJOURNAL OF MICROSCOPY, Issue 3 2010O. RAMÍREZ Summary The quantification of colocalizing signals in multichannel fluorescence microscopy images depends on the reliable segmentation of corresponding regions of interest, on the selection of appropriate colocalization coefficients, and on a robust statistical criterion to discriminate true from random colocalization. Here, we introduce a confined displacement algorithm based on image correlation spectroscopy in combination with Manders colocalization coefficients M1ROI and M2ROI to quantify true and random colocalization of a given florescence pattern. We show that existing algorithms based on block scrambling exaggerate the randomization of fluorescent patterns with resulting inappropriately narrow probability density functions and false significance of true colocalization in terms of p values. We further confine our approach to subcellular compartments and show that true and random colocalization can be analysed for model dendrites and for GABAB receptor subunits GABABR1/2 in cultured hippocampal neurons. Together, we demonstrate that the confined displacement algorithm detects true colocalization of specific fluorescence patterns down to subcellular levels. [source] Fabrication of Patterned Polydiacetylene Composite Films Using a Replica-Molding (REM) TechniqueMACROMOLECULAR RAPID COMMUNICATIONS, Issue 3 2010Oktay Yarimaga Abstract Functional three-dimensional (3D) micropatterns of diacetylene supramolecules embedded in a host polymer have been successfully fabricated by a replica-molding (REM) technique. Dimensional reduction as a result of liquid evaporation during the curing process does not affect the conformational features of the transferred patterns. Polymerization of the diacetylene vesicles using 254,nm UV-light irradiation from the back-side of the transparent substrate induces blue colored polydiacetylene (PDA) micro-images. Interestingly, the polymerization selectively occurs in the molded areas because of the sub-300,nm light blocking property of SU-8. 3D fluorescence patterns are readily obtained by heat treatment of the blue images on the film. [source] Several distinct localization patterns for penicillin-binding proteins in Bacillus subtilisMOLECULAR MICROBIOLOGY, Issue 3 2004Dirk-Jan Scheffers Summary Bacterial cell shape is determined by a rigid external cell wall. In most non-coccoid bacteria, this shape is also determined by an internal cytoskeleton formed by the actin homologues MreB and/or Mbl. To gain further insights into the topological control of cell wall synthesis in bacteria, we have constructed green fluorescent protein (GFP) fusions to all 11 penicillin-binding proteins (PBPs) expressed during vegetative growth of Bacillus subtilis. The localization of these fusions was studied in a wild-type background as well as in strains deficient in FtsZ, MreB or Mbl. PBP3 and PBP4a localized specifically to the lateral wall, in distinct foci, whereas PBP1 and PBP2b localized specifically to the septum. All other PBPs localized to both the septum and the lateral cell wall, sometimes with irregular distribution along the lateral wall or a preference for the septum. This suggests that cell wall synthesis is not dispersed but occurs at specific places along the lateral cell wall. The results implicate PBP3, PBP5 and PBP4a, and possibly PBP4, in lateral wall growth. Localization of PBPs to the septum was found to be dependent on FtsZ, but the GFP,PBP fluorescence patterns were not detectably altered in the absence of MreB or Mbl. [source] U-serrated immunodeposition pattern differentiates type VII collagen targeting bullous diseases from other subepidermal bullous autoimmune diseasesBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2004R.M. Vodegel Summary Background, Epidermolysis bullosa acquisita (EBA) can be differentiated from other subepidermal bullous diseases by sophisticated techniques such as immunoelectron microscopy, salt-split skin antigen mapping, fluorescence overlay antigen mapping, immunoblot and enzyme-linked immunosorbent assay. Objectives, To determine whether the diagnosis can also be made by routine direct immunofluorescence microscopy. Methods, We studied frozen skin biopsies from 157 patients with various subepidermal immunobullous diseases. Results, We found three distinct ,linear' fluorescence patterns at the basement membrane zone: true linear, n-serrated and u-serrated. The true linear pattern, often seen in conjunction with either the n- or the u-serrated pattern, was found in any subepidermal immunobullous disease with nongranular depositions. In bullous pemphigoid, mucous membrane pemphigoid, antiepiligrin cicatricial pemphigoid, p200 pemphigoid and linear IgA disease the n-serrated pattern was found, corresponding with depositions located in hemidesmosomes, lamina lucida or lamina densa. However, in EBA and bullous systemic lupus erythematosus the u-serrated staining pattern was seen, corresponding with the ultralocalization of type VII collagen in the sublamina densa zone. The diagnosis of EBA with IgG or IgA autoantibodies directed against type VII collagen was confirmed by immunoelectron microscopy, salt-split skin antigen mapping, fluorescence overlay antigen mapping or immunoblotting. Conclusions, Using this pattern recognition by direct immunofluorescence microscopy we discovered several cases of EBA which would otherwise have been erroneously diagnosed as a form of pemphigoid or linear IgA disease. [source] | ||||||||||||||||