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Sample records for apical f-actin network

  1. Microstructural model for cyclic hardening in F-actin networks crosslinked by α-actinin

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    López-Menéndez, Horacio; Rodríguez, José Félix

    2016-06-01

    The rheology of F-actin networks has attracted a great attention during the last years. In order to gain a complete understanding of the rheological properties of these novel materials, it is necessary the study in a large deformations regime to alter their internal structure. In this sense, Schmoller et al. (2010) showed that the reconstituted networks of F-actin crosslinked with α-actinin unexpectedly harden when they are subjected to a cyclical shear. This observation contradicts the expected Mullins effect observed in most soft materials, such as rubber and living tissues, where a pronounced softening is observed when they are cyclically deformed. We think that the key to understand this stunning effect is the gelation process. To define it, the most relevant constituents are the chemical crosslinks - α-actinin -, the physical crosslinks - introduced by the entanglement of the semiflexible network - and the interaction between them. As a consequence of this interaction, a pre-stressed network emerges and introduces a feedback effect, where the pre-stress also regulates the adhesion energy of the α-actinin, setting the structure in a metastable reference configuration. Therefore, the external loads and the evolvement of the trapped stress drive the microstructural changes during the cyclic loading protocol. In this work, we propose a micromechanical model into the framework of nonlinear continuum mechanics. The mechanics of the F-actin filaments is modelled using the wormlike chain model for semiflexible filaments and the gelation process is modelled as mesoscale dynamics for the α-actinin and physical crosslink. The model has been validated with reported experimental results.

  2. Self-organized gels in DNA/F-actin mixtures without crosslinkers: networks of induced nematic domains with tunable density.

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    Lai, Ghee Hwee; Butler, John C; Zribi, Olena V; Smalyukh, Ivan I; Angelini, Thomas E; Purdy, Kirstin R; Golestanian, Ramin; Wong, Gerard C L

    2008-11-21

    We examine mixtures of DNA and filamentous actin (F-actin) as a model system of like-charged rigid rods and flexible chains. Confocal microscopy reveals the formation of elongated nematic F-actin domains reticulated via defect-free vertices into a network embedded in a mesh of random DNA. Synchrotron x-ray scattering results indicate that the DNA mesh squeezes the F-actin domains into a nematic state with an interactin spacing that decreases with increasing DNA concentration as d(actin) proportional, variantrho(DNA)(-1/2). Interestingly, the system changes from a counterion-controlled regime to a depletion-controlled regime with added salt, with drastic consequences for the osmotic pressure induced phase behavior.

  3. Ena/VASP Enabled is a highly processive actin polymerase tailored to self-assemble parallel-bundled F-actin networks with Fascin.

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    Winkelman, Jonathan D; Bilancia, Colleen G; Peifer, Mark; Kovar, David R

    2014-03-18

    Filopodia are exploratory finger-like projections composed of multiple long, straight, parallel-bundled actin filaments that protrude from the leading edge of migrating cells. Drosophila melanogaster Enabled (Ena) is a member of the Ena/vasodilator-stimulated phosphoprotein protein family, which facilitates the assembly of filopodial actin filaments that are bundled by Fascin. However, the mechanism by which Ena and Fascin promote the assembly of uniformly thick F-actin bundles that are capable of producing coordinated protrusive forces without buckling is not well understood. We used multicolor evanescent wave fluorescence microscopy imaging to follow individual Ena molecules on both single and Fascin-bundled F-actin in vitro. Individual Ena tetramers increase the elongation rate approximately two- to threefold and inhibit capping protein by remaining processively associated with the barbed end for an average of ∼10 s in solution, for ∼60 s when immobilized on a surface, and for ∼110 s when multiple Ena tetramers are clustered on a surface. Ena also can gather and simultaneously elongate multiple barbed ends. Collectively, these properties could facilitate the recruitment of Fascin and initiate filopodia formation. Remarkably, we found that Ena's actin-assembly properties are tunable on Fascin-bundled filaments, facilitating the formation of filopodia-like F-actin networks without tapered barbed ends. Ena-associated trailing barbed ends in Fascin-bundled actin filaments have approximately twofold more frequent and approximately fivefold longer processive runs, allowing them to catch up with leading barbed ends efficiently. Therefore, Fascin and Ena cooperate to extend and maintain robust filopodia of uniform thickness with aligned barbed ends by a unique mechanistic cycle.

  4. Lifeact-mEGFP reveals a dynamic apical F-actin network in tip growing plant cells.

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    Luis Vidali

    Full Text Available BACKGROUND: Actin is essential for tip growth in plants. However, imaging actin in live plant cells has heretofore presented challenges. In previous studies, fluorescent probes derived from actin-binding proteins often alter growth, cause actin bundling and fail to resolve actin microfilaments. METHODOLOGY/PRINCIPAL FINDINGS: In this report we use Lifeact-mEGFP, an actin probe that does not affect the dynamics of actin, to visualize actin in the moss Physcomitrella patens and pollen tubes from Lilium formosanum and Nicotiana tobaccum. Lifeact-mEGFP robustly labels actin microfilaments, particularly in the apex, in both moss protonemata and pollen tubes. Lifeact-mEGFP also labels filamentous actin structures in other moss cell types, including cells of the gametophore. CONCLUSIONS/SIGNIFICANCE: Lifeact-mEGFP, when expressed at optimal levels does not alter moss protonemal or pollen tube growth. We suggest that Lifeact-mEGFP represents an exciting new versatile probe for further studies of actin's role in tip growing plant cells.

  5. F-actin distribution at nodes of Ranvier and Schmidt-Lanterman incisures in mammalian sciatic nerves.

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    Kun, Alejandra; Canclini, Lucía; Rosso, Gonzalo; Bresque, Mariana; Romeo, Carlos; Hanusz, Alicia; Cal, Karina; Calliari, Aldo; Sotelo Silveira, José; Sotelo, José R

    2012-07-01

    Very little is known about the function of the F-actin cytoskeleton in the regeneration and pathology of peripheral nerve fibers. The actin cytoskeleton has been associated with maintenance of tissue structure, transmission of traction and contraction forces, and an involvement in cell motility. Therefore, the state of the actin cytoskeleton strongly influences the mechanical properties of cells and intracellular transport therein. In this work, we analyze the distribution of F-actin at Schmidt-Lanterman Incisures (SLI) and nodes of Ranvier (NR) domains in normal, regenerating and pathologic Trembler J (TrJ/+) sciatic nerve fibers, of rats and mice. F-actin was quantified and it was found increased in TrJ/+, both in SLI and NR. However, SLI and NR of regenerating rat sciatic nerve did not show significant differences in F-actin, as compared with normal nerves. Cytochalasin-D and Latrunculin-A were used to disrupt the F-actin network in normal and regenerating rat sciatic nerve fibers. Both drugs disrupt F-actin, but in different ways. Cytochalasin-D did not disrupt Schwann cell (SC) F-actin at the NR. Latrunculin-A did not disrupt F-actin at the boundary region between SC and axon at the NR domain. We surmise that the rearrangement of F-actin in neurological disorders, as presented here, is an important feature of TrJ/+ pathology as a Charcot-Marie-Tooth (CMT) model.

  6. Piracy of decay-accelerating factor (CD55) signal transduction by the diffusely adhering strain Escherichia coli C1845 promotes cytoskeletal F-actin rearrangements in cultured human intestinal INT407 cells.

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    Peiffer, I; Servin, A L; Bernet-Camard, M F

    1998-09-01

    Diffusely adhering Escherichia coli (DAEC) C1845 (clinical isolate) harboring the fimbrial adhesin F1845 can infect cultured human differentiated intestinal epithelial cells; this process is followed by the disassembly of the actin network in the apical domain. The aim of this study was to examine the mechanism by which DAEC C1845 promotes F-actin rearrangements. For this purpose, we used a human embryonic intestinal cell line (INT407) expressing the membrane-associated glycosylphosphatidylinositol (GPI) protein-anchored decay-accelerating factor (DAF), the receptor of the F1845 adhesin. We show here that infection of INT407 cells by DAEC C1845 can provoke dramatic F-actin rearrangements without cell entry. Clustering of phosphotyrosines was observed, revealing that the DAEC C1845-DAF interaction involves the recruitment of signal transduction molecules. A pharmacological approach with a subset of inhibitors of signal transduction molecules was used to identify the cascade of signal transduction molecules that are coupled to the DAF, that are activated upon infection, and that promote the F-actin rearrangements. DAEC C1845-induced F-actin rearrangements can be blocked dose dependently by protein tyrosine kinase, phospholipase Cgamma, phosphatidylinositol 3-kinase, protein kinase C, and Ca2+ inhibitors. F-actin rearrangements and blocking by inhibitors were observed after infection of the cells with two E. coli recombinants carrying the plasmids containing the fimbrial adhesin F1845 or the fimbrial hemagglutinin Dr, belonging to the same family of adhesins. These findings show that the DAEC Dr family of pathogens promotes alterations in the intestinal cell cytoskeleton by piracy of the DAF-GPI signal cascade without bacterial cell entry.

  7. F-actin cytoskeleton and the fate of organelles in chromaffin cells.

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    Villanueva, José; Gimenez-Molina, Yolanda; Viniegra, Salvador; Gutiérrez, Luis M

    2016-06-01

    In addition to playing a fundamental structural role, the F-actin cytoskeleton in neuroendocrine chromaffin cells has a prominent influence on governing the molecular mechanism and regulating the secretory process. Performing such roles, the F-actin network might be essential to first transport, and later locate the cellular organelles participating in the secretory cycle. Chromaffin granules are transported from the internal cytosolic regions to the cell periphery along microtubular and F-actin structures. Once in the cortical region, they are embedded in the F-actin network where these vesicles experience restrictions in motility. Similarly, mitochondria transport is affected by both microtubule and F-actin inhibitors and suffers increasing motion restrictions when they are located in the cortical region. Therefore, the F-actin cortex is a key factor in defining the existence of two populations of cortical and perinuclear granules and mitochondria which could be distinguished by their different location and mobility. Interestingly, other important organelles for controlling intracellular calcium levels, such as the endoplasmic reticulum network, present clear differences in distribution and much lower mobility than chromaffin vesicles and mitochondria. Nevertheless, both mitochondria and the endoplasmic reticulum appear to distribute in the proximity of secretory sites to fulfill a pivotal role, forming triads with calcium channels ensuring the fine tuning of the secretory response. This review presents the contributions that provide the basis for our current view regarding the influence that F-actin has on the distribution of organelles participating in the release of catecholamines in chromaffin cells, and summarizes this knowledge in simple models. In chromaffin cells, organelles such as granules and mitochondria distribute forming cortical and perinuclear populations whereas others like the ER present homogenous distributions. In the present review we discuss

  8. Enterocyte loss of polarity and gut wound healing rely upon the F-actin-severing function of villin.

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    Ubelmann, Florent; Chamaillard, Mathias; El-Marjou, Fatima; Simon, Anthony; Netter, Jeanne; Vignjevic, Danijela; Nichols, Buford L; Quezada-Calvillo, Roberto; Grandjean, Teddy; Louvard, Daniel; Revenu, Céline; Robine, Sylvie

    2013-04-09

    Efficient wound healing is required to maintain the integrity of the intestinal epithelial barrier because of its constant exposure to a large variety of environmental stresses. This process implies a partial cell depolarization and the acquisition of a motile phenotype that involves rearrangements of the actin cytoskeleton. Here we address how polarized enterocytes harboring actin-rich apical microvilli undergo extensive cell remodeling to drive injury repair. Using live imaging technologies, we demonstrate that enterocytes in vitro and in vivo rapidly depolarize their microvilli at the wound edge. Through its F-actin-severing activity, the microvillar actin-binding protein villin drives both apical microvilli disassembly in vitro and in vivo and promotes lamellipodial extension. Photoactivation experiments indicate that microvillar actin is mobilized at the lamellipodium, allowing optimal migration. Finally, efficient repair of colonic mechanical injuries requires villin severing of F-actin, emphasizing the importance of villin function in intestinal homeostasis. Thus, villin severs F-actin to ensure microvillus depolarization and enterocyte remodeling upon injury. This work highlights the importance of specialized apical pole disassembly for the repolarization of epithelial cells initiating migration.

  9. The circular F-actin bundles provide a track for turnaround and bidirectional movement of mitochondria in Arabidopsis root hair.

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    Yu Zhang

    Full Text Available The movement of organelles in root hairs primarily occurs along the actin cytoskeleton. Circulation and "reverse fountain" cytoplasmic streaming constitute the typical forms by which most organelles (such as mitochondria and the Golgi apparatus in plant root hair cells engage in bidirectional movement. However, there remains a lack of in-depth research regarding the relationship between the distribution of the actin cytoskeleton and turnaround organelle movement in plant root hair cells.In this paper, Arabidopsis seedlings that had been stably transformed with a GFP-ABD2-GFP (green fluorescent protein-actin-binding domain 2-green fluorescent protein construct were utilized to study the distribution of bundles of filamentous (F-actin and the directed motion of mitochondria along these bundles in root hairs. Observations with a confocal laser scanning microscope revealed that there were widespread circular F-actin bundles in the epidermal cells and root hairs of Arabidopsis roots. In root hairs, these circular bundles primarily start at the sub-apical region, which is the location where the turnaround movement of organelles occurs. MitoTracker probes were used to label mitochondria, and the dynamic observation of root hair cells with a confocal laser scanning microscope indicated that turnaround mitochondrial movement occurred along circular F-actin bundles.Relevant experimental results demonstrated that the circular F-actin bundles provide a track for the turnaround and bidirectional movement of mitochondria.

  10. Actin-Capping Protein and the Hippo pathway regulate F-actin and tissue growth in Drosophila.

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    Fernández, Beatriz García; Gaspar, Pedro; Brás-Pereira, Catarina; Jezowska, Barbara; Rebelo, Sofia Raquel; Janody, Florence

    2011-06-01

    The conserved Hippo tumor suppressor pathway is a key kinase cascade that controls tissue growth by regulating the nuclear import and activity of the transcription co-activator Yorkie. Here, we report that the actin-Capping Protein αβ heterodimer, which regulates actin polymerization, also functions to suppress inappropriate tissue growth by inhibiting Yorkie activity. Loss of Capping Protein activity results in abnormal accumulation of apical F-actin, reduced Hippo pathway activity and the ectopic expression of several Yorkie target genes that promote cell survival and proliferation. Reduction of two other actin-regulatory proteins, Cofilin and the cyclase-associated protein Capulet, cause abnormal F-actin accumulation, but only the loss of Capulet, like that of Capping Protein, induces ectopic Yorkie activity. Interestingly, F-actin also accumulates abnormally when Hippo pathway activity is reduced or abolished, independently of Yorkie activity, whereas overexpression of the Hippo pathway component expanded can partially reverse the abnormal accumulation of F-actin in cells depleted for Capping Protein. Taken together, these findings indicate a novel interplay between Hippo pathway activity and actin filament dynamics that is essential for normal growth control.

  11. Control of nuclear organization by F-actin binding proteins.

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    Pfisterer, Karin; Jayo, Asier; Parsons, Maddy

    2017-01-06

    The regulation of nuclear shape and deformability is a key factor in controlling diverse events from embryonic development to cancer cell metastasis, but the mechanisms governing this process are still unclear. Our recent study demonstrated an unexpected role for the F-actin bundling protein fascin in controlling nuclear plasticity through a direct interaction with Nesprin-2. Nesprin-2 is a component of the LINC complex that is known to couple the F-actin cytoskeleton to the nuclear envelope. We demonstrated that fascin, which is predominantly associated with peripheral F-actin rich filopodia, binds directly to Nesprin-2 at the nuclear envelope in a range of cell types. Depleting fascin or specifically blocking the fascin-Nesprin-2 complex leads to defects in nuclear polarization, movement and cell invasion. These studies reveal a novel role for an F-actin bundling protein in control of nuclear plasticity and underline the importance of defining nuclear-associated roles for F-actin binding proteins in future.

  12. Adhesive F-actin waves: a novel integrin-mediated adhesion complex coupled to ventral actin polymerization.

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    Lindsay B Case

    Full Text Available At the leading lamellipodium of migrating cells, protrusion of an Arp2/3-nucleated actin network is coupled to formation of integrin-based adhesions, suggesting that Arp2/3-mediated actin polymerization and integrin-dependent adhesion may be mechanistically linked. Arp2/3 also mediates actin polymerization in structures distinct from the lamellipodium, in "ventral F-actin waves" that propagate as spots and wavefronts along the ventral plasma membrane. Here we show that integrins engage the extracellular matrix downstream of ventral F-actin waves in several mammalian cell lines as well as in primary mouse embryonic fibroblasts. These "adhesive F-actin waves" require a cycle of integrin engagement and disengagement to the extracellular matrix for their formation and propagation, and exhibit morphometry and a hierarchical assembly and disassembly mechanism distinct from other integrin-containing structures. After Arp2/3-mediated actin polymerization, zyxin and VASP are co-recruited to adhesive F-actin waves, followed by paxillin and vinculin, and finally talin and integrin. Adhesive F-actin waves thus represent a previously uncharacterized integrin-based adhesion complex associated with Arp2/3-mediated actin polymerization.

  13. Cell shape change and invagination of the cephalic furrow involves reorganization of F-actin.

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    Spencer, Allison K; Siddiqui, Bilal A; Thomas, Jeffrey H

    2015-06-15

    Invagination of epithelial sheets to form furrows is a fundamental morphogenetic movement and is found in a variety of developmental events including gastrulation and vertebrate neural tube formation. The cephalic furrow is a deep epithelial invagination that forms during Drosophila gastrulation. In the first phase of cephalic furrow formation, the initiator cells that will lead invagination undergo apicobasal shortening and apical constriction in the absence of epithelial invagination. In the second phase of cephalic furrow formation, the epithelium starts to invaginate, accompanied by both basal expansion and continued apicobasal shortening of the initiator cells. The cells adjacent to the initiator cells also adopt wedge shapes, but only after invagination is well underway. Myosin II does not appear to drive apical constriction in cephalic furrow formation. However, cortical F-actin is increased in the apices of the initiator cells and in invaginating cells during both phases of cephalic furrow formation. These findings suggest that a novel mechanism for epithelial invagination is involved in cephalic furrow formation.

  14. Cell stress promotes the association of phosphorylated HspB1 with F-actin.

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    Joseph P Clarke

    Full Text Available Previous studies have suggested that the small heat shock protein, HspB1, has a direct influence on the dynamics of cytoskeletal elements, in particular, filamentous actin (F-actin polymerization. In this study we have assessed the influence of HspB1 phosphorylation on its interaction(s with F-actin. We first determined the distribution of endogenous non-phosphorylated HspB1, phosphorylated HspB1 and F-actin in neuroendocrine PC12 cells by immunocytochemistry and confocal microscopy. We then investigated a potential direct interaction between HspB1 with F-actin by precipitating F-actin directly with biotinylated phalloidin followed by Western analyses; the reverse immunoprecipitation of HspB1 was also carried out. The phosphorylation influence of HspB1 in this interaction was investigated by using pharmacologic inhibition of p38 MAPK. In control cells, HspB1 interacts with F-actin as a predominantly non-phosphorylated protein, but subsequent to stress there is a redistribution of HspB1 to the cytoskeletal fraction and a significantly increased association of pHspB1 with F-actin. Our data demonstrate HspB1 is found in a complex with F-actin both in phosphorylated and non-phosphorylated forms, with an increased association of pHspB1 with F-actin after heat stress. Overall, our study combines both cellular and biochemical approaches to show cellular localization and direct demonstration of an interaction between endogenous HspB1 and F-actin using methodolgy that specifically isolates F-actin.

  15. Three-dimensional Organization of Layered Apical Cytoskeletal Networks Associated with Mouse Airway Tissue Development

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    Tateishi, Kazuhiro; Nishida, Tomoki; Inoue, Kanako; Tsukita, Sachiko

    2017-03-01

    The cytoskeleton is an essential cellular component that enables various sophisticated functions of epithelial cells by forming specialized subcellular compartments. However, the functional and structural roles of cytoskeletons in subcellular compartmentalization are still not fully understood. Here we identified a novel network structure consisting of actin filaments, intermediate filaments, and microtubules directly beneath the apical membrane in mouse airway multiciliated cells and in cultured epithelial cells. Three-dimensional imaging by ultra-high voltage electron microscopy and immunofluorescence revealed that the morphological features of each network depended on the cell type and were spatiotemporally integrated in association with tissue development. Detailed analyses using Odf2 mutant mice, which lack ciliary basal feet and apical microtubules, suggested a novel contribution of the intermediate filaments to coordinated ciliary beating. These findings provide a new perspective for viewing epithelial cell differentiation and tissue morphogenesis through the structure and function of apical cytoskeletal networks.

  16. F-actin distribution and function during sexual differentiation in Schizosaccharomyces pombe

    DEFF Research Database (Denmark)

    Petersen, J; Nielsen, O; Egel, R;

    1998-01-01

    Sexual differentiation in Schizosaccharomyces pombe is induced from the G1 phase of the cell cycle by nitrogen starvation and the presence of mating pheromones. We describe the distribution of F-actin during sexual differentiation. Cortical F-actin dots have previously been shown to be restricted...

  17. F-actin distribution and function during sexual differentiation in Schizosaccharomyces pombe

    DEFF Research Database (Denmark)

    Petersen, J; Nielsen, O; Egel, R

    1998-01-01

    towards the projection tip at one end of the cell. Following cell fusion, F-actin dots were randomly scattered during the horsetail movement that precedes meiosis I and remained scattered until prometaphase or metaphase of meiosis II, when they concentrated around the nucleus. F-actin was seen...... on the lagging face of the nuclei which faced the partner nucleus during anaphase B of meiosis II. Early on in this anaphase F-actin was also seen on the opposite side of the nucleus, near the spindle pole body. F-actin accumulated within the spores in the mature ascus. Treatment with the actin depolymerising...... drug Latrunculin A showed that F-actin is required for cell fusion and spore formation. Latrunculin A treatment extended all stages from karyogamy to meiosis I. The S. pombe homologue of the actin binding protein profilin, Cdc3, was shown to be required for conjugation. Cdc3 co...

  18. 5DFRXXL region of long myosin light chain kinase causes F-actin bundle formation

    Institute of Scientific and Technical Information of China (English)

    YANG Chunxiang; WEI Dongmei; CHEN Chen; YU Weiping; ZHU Minsheng

    2005-01-01

    Long myosin light chain kinase (L-MLCK) contains five DFRXXL motifs with ability to bind F-actin. Binding stoichiometry data indicated that each DFRXXL motif might bind each G-actin, but its biological significance remained unknown. We hypothesized that L-MLCK might act as an F-actin bundle peptides by its multiple binding sites of 5DFRXXL motifs to actin. In order to characterize F-actin-bundle formation properties of 5DFRXXL region of long myosin light chain kinase, we expressed and purified 5DFRXXL peptides tagged with HA in vitro. The properties of 5DFRXXL peptides binding to myofilaments or F-actin were analyzed by binding stoichiometries assays. The results indicated that 5DFRXXL peptides bound to myofilaments or F-actin with high affinity. KD values of 5DFRXXL binding to myofilaments and F-actin were 0.45 and 0.41 μmol/L, re- spectively. Cross-linking assay demonstrated that 5DFRXXL peptides could bundle F-actin efficiently. Typical F-actin bundles were observed morphologically through determina- tion of confocal and electron microscopy after adding 5DFRXXL peptides. After transfection of pEGFP-5DFRXXL plasmid into eukaryocyte, spike structure was observed around cell membrane edge. We guess that such structure formation may be attributable to F-actin over-bundle forma- tion caused by 5DFRXXL peptides. Therefore, we suppose that L-MLCK may be a new bundling protein and somehow play a certain role in organization of cell skeleton besides mediating cell contraction by it kinase activity.

  19. Dendritic cell podosome dynamics does not depend on the F-actin regulator SWAP-70.

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    Anne Götz

    Full Text Available In addition to classical adhesion structures like filopodia or focal adhesions, dendritic cells similar to macrophages and osteoclasts assemble highly dynamic F-actin structures called podosomes. They are involved in cellular processes such as extracellular matrix degradation, bone resorption by osteoclasts, and trans-cellular diapedesis of lymphocytes. Besides adhesion and migration, podosomes enable dendritic cells to degrade connective tissue by matrix metalloproteinases. SWAP-70 interacts with RhoGTPases and F-actin and regulates migration of dendritic cells. SWAP-70 deficient osteoclasts are impaired in F-actin-ring formation and bone resorption. In the present study, we demonstrate that SWAP-70 is not required for podosome formation and F-actin turnover in dendritic cells. Furthermore, we found that toll-like receptor 4 ligand induced podosome disassembly and podosome-mediated matrix degradation is not affected by SWAP-70 in dendritic cells. Thus, podosome formation and function in dendritic cells is independent of SWAP-70.

  20. Modulating F-actin organization induces organ growth by affecting the Hippo pathway

    OpenAIRE

    Sansores-Garcia, Leticia; Bossuyt, Wouter; Wada, Ken-Ichi; Yonemura, Shigenobu; Tao, Chunyao; Sasaki, Hiroshi; Halder, Georg

    2011-01-01

    This study identifies actin organization as an upstream regulator of the Hippo pathway: F-actin accumulation promotes Yorkie-dependent transcriptional activation. This modulation of Hippo signalling by actin regulators controls organ growth in Drosophila.

  1. Spectrin-dependent and -independent association of F-actin with the erythrocyte membrane.

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    Cohen, C M; Foley, S F

    1980-08-01

    Binding of F-actin to spectrin-actin-depleted erythrocyte membrane inside-out vesicles was measured using [3H]F-actin. F-actin binding to vesicles at 25 degrees C was stimulated 5-10 fold by addition of spectrin dimers or tetramers to vesicles. Spectrin tetramer was twice as effective as dimer in stimulating actin binding, but neither tetramer nor dimer stimulated binding at 4 degrees C. The addition of purified erythrocyte membrane protein band 4.1 to spectrin-reconstituted vesicles doubled their actin-binding capacity. Trypsinization of unreconstituted vesicles that contain ghosts, decreased their F-actin-binding capacity by 70%. Whereas little or none of the residual spectrin was affected by trypsinization, band 4.1 was significantly degraded. Our results show that spectrin can anchor actin filaments to the cytoplasmic surface of erythrocyte membranes and suggest that band 4.1 may be importantly involved in the association.

  2. Hormonal networks involved in apical hook development in darkness and their response to light

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    Maria Agustina Mazzella

    2014-02-01

    Full Text Available In darkness, the dicot seedlings produces an apical hook as result of differential cell division and extension at opposite sides of the hypocotyl. This hook protects the apical meristem from mechanical damage during seedling emergence from the soil. In darkness, gibberellins act via the DELLA-PIF (PHYTOCHROME INTERACTING FACTORs pathway, and ethylene acts via the EIN3/EIL1 (ETHYLENE INSENSITIE 3/EIN3 like 1-HLS1 (HOOKLESS 1 pathway to control the asymmetric accumulation of auxin required for apical hook formation and maintenance. These core pathways form a network with multiple points of connection. Light perception by phytochromes and cryptochromes reduces the activity of PIFs and CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1 --both required for hook formation in darkness--, lowers the levels of gibberellins, and triggers hook opening as a component of the switch between heterotrophic and photoautotrophic development. Apical hook opening is thus a suitable model to study the convergence of endogenous and exogenous signals on the control of cell division and cell growth.

  3. Peroxynitrite induces F-actin depolymerization and blockade of myosin ATPase stimulation.

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    Tiago, Teresa; Ramos, Susana; Aureliano, Manuel; Gutiérrez-Merino, Carlos

    2006-03-31

    Treatment of F-actin with the peroxynitrite-releasing agent 3-morpholinosydnonimine (SIN-1) produced a dose-dependent F-actin depolymerization. This is due to released peroxynitrite because it is not produced by 'decomposed SIN-1', and it is prevented by superoxide dismutase concentrations efficiently preventing peroxynitrite formation. F-actin depolymerization has been found to be very sensitive to peroxynitrite, as exposure to fluxes as low as 50-100nM peroxynitrite leads to nearly 50% depolymerization in about 1h. G-actin polymerization is also impaired by peroxynitrite although with nearly 2-fold lower sensitivity. Exposure of F-actin to submicromolar fluxes of peroxynitrite produced cysteine oxidation and also a blockade of the ability of actin to stimulate myosin ATPase activity. Our results suggest that an imbalance of the F-actin/G-actin equilibrium can account for the observed structural and functional impairment of myofibrils under the peroxynitrite-mediated oxidative stress reported for some pathophysiological conditions.

  4. Regulation of bone mass and osteoclast function depend on the F-actin modulator SWAP-70.

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    Garbe, Annette I; Roscher, Anne; Schüler, Christiane; Lutter, Anne-Helen; Glösmann, Martin; Bernhardt, Ricardo; Chopin, Michael; Hempel, Ute; Hofbauer, Lorenz C; Rammelt, Stefan; Egerbacher, Monika; Erben, Reinhold G; Jessberger, Rolf

    2012-10-01

    Bone remodeling involves tightly regulated bone-resorbing osteoclasts and bone-forming osteoblasts. Determining osteoclast function is central to understanding bone diseases such as osteoporosis and osteopetrosis. Here, we report a novel function of the F-actin binding and regulatory protein SWAP-70 in osteoclast biology. F-actin ring formation, cell morphology, and bone resorption are impaired in Swap-70(-/-) osteoclasts, whereas the expression of osteoclast differentiation markers induced in vitro by macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-κB ligand (RANKL) remains unaffected. Swap-70(-/-) mice develop osteopetrosis with increased bone mass, abnormally dense bone, and impaired osteoclast function. Ectopic expression of SWAP-70 in Swap-70(-/-) osteoclasts in vitro rescues their deficiencies in bone resorption and F-actin ring formation. Rescue requires a functional pleckstrin homology (PH) domain, known to support membrane localization of SWAP-70, and the F-actin binding domain. Transplantation of SWAP-70-proficient bone marrow into Swap-70(-/-) mice restores osteoclast resorption capacity in vivo. The identification of the role of SWAP-70 in promoting osteoclast function through modulating membrane-proximal F-actin rearrangements reveals a new pathway to control osteoclasts and bone homeostasis.

  5. Dendrite architecture organized by transcriptional control of the F-actin nucleator Spire.

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    Ferreira, Tiago; Ou, Yimiao; Li, Sally; Giniger, Edward; van Meyel, Donald J

    2014-02-01

    The architectures of dendritic trees are crucial for the wiring and function of neuronal circuits because they determine coverage of receptive territories, as well as the nature and strength of sensory or synaptic inputs. Here, we describe a cell-intrinsic pathway sculpting dendritic arborization (da) neurons in Drosophila that requires Longitudinals Lacking (Lola), a BTB/POZ transcription factor, and its control of the F-actin cytoskeleton through Spire (Spir), an actin nucleation protein. Loss of Lola from da neurons reduced the overall length of dendritic arbors, increased the expression of Spir, and produced inappropriate F-actin-rich dendrites at positions too near the cell soma. Selective removal of Lola from only class IV da neurons decreased the evasive responses of larvae to nociception. The increased Spir expression contributed to the abnormal F-actin-rich dendrites and the decreased nocifensive responses because both were suppressed by reduced dose of Spir. Thus, an important role of Lola is to limit expression of Spir to appropriate levels within da neurons. We found Spir to be expressed in dendritic arbors and to be important for their development. Removal of Spir from class IV da neurons reduced F-actin levels and total branch number, shifted the position of greatest branch density away from the cell soma, and compromised nocifensive behavior. We conclude that the Lola-Spir pathway is crucial for the spatial arrangement of branches within dendritic trees and for neural circuit function because it provides balanced control of the F-actin cytoskeleton.

  6. Quantification of Filamentous Actin (F-actin) Puncta in Rat Cortical Neurons.

    Science.gov (United States)

    Li, Hailong; Aksenova, Marina; Bertrand, Sarah J; Mactutus, Charles F; Booze, Rosemarie

    2016-02-10

    Filamentous actin protein (F-actin) plays a major role in spinogenesis, synaptic plasticity, and synaptic stability. Changes in dendritic F-actin rich structures suggest alterations in synaptic integrity and connectivity. Here we provide a detailed protocol for culturing primary rat cortical neurons, Phalloidin staining for F-actin puncta, and subsequent quantification techniques. First, the frontal cortex of E18 rat embryos are dissociated into low-density cell culture, then the neurons grown in vitro for at least 12-14 days. Following experimental treatment, the cortical neurons are stained with AlexaFluor 488 Phalloidin (to label the dendritic F-actin puncta) and microtubule-associated protein 2 (MAP2; to validate the neuronal cells and dendritic integrity). Finally, specialized software is used to analyze and quantify randomly selected neuronal dendrites. F-actin rich structures are identified on second order dendritic branches (length range 25-75 µm) with continuous MAP2 immunofluorescence. The protocol presented here will be a useful method for investigating changes in dendritic synapse structures subsequent to experimental treatments.

  7. Technical advance: identification of plant actin-binding proteins by F-actin affinity chromatography

    Science.gov (United States)

    Hu, S.; Brady, S. R.; Kovar, D. R.; Staiger, C. J.; Clark, G. B.; Roux, S. J.; Muday, G. K.

    2000-01-01

    Proteins that interact with the actin cytoskeleton often modulate the dynamics or organization of the cytoskeleton or use the cytoskeleton to control their localization. In plants, very few actin-binding proteins have been identified and most are thought to modulate cytoskeleton function. To identify actin-binding proteins that are unique to plants, the development of new biochemical procedures will be critical. Affinity columns using actin monomers (globular actin, G-actin) or actin filaments (filamentous actin, F-actin) have been used to identify actin-binding proteins from a wide variety of organisms. Monomeric actin from zucchini (Cucurbita pepo L.) hypocotyl tissue was purified to electrophoretic homogeneity and shown to be native and competent for polymerization to actin filaments. G-actin, F-actin and bovine serum albumin affinity columns were prepared and used to separate samples enriched in either soluble or membrane-associated actin-binding proteins. Extracts of soluble actin-binding proteins yield distinct patterns when eluted from the G-actin and F-actin columns, respectively, leading to the identification of a putative F-actin-binding protein of approximately 40 kDa. When plasma membrane-associated proteins were applied to these columns, two abundant polypeptides eluted selectively from the F-actin column and cross-reacted with antiserum against pea annexins. Additionally, a protein that binds auxin transport inhibitors, the naphthylphthalamic acid binding protein, which has been previously suggested to associate with the actin cytoskeleton, was eluted in a single peak from the F-actin column. These experiments provide a new approach that may help to identify novel actin-binding proteins from plants.

  8. Vacuole formation in mast cells responding to osmotic stress and to F-actin disassembly

    DEFF Research Database (Denmark)

    Koffer, Anna; Williams, Mark; Johansen, Torben

    2002-01-01

    Fluorescent probes were used to visualize the morphology of membranes and of F-actin in rat peritoneal mast cells, exposed to hyperosmotic medium and consequently reversed to isotonicity. Hypertonicity induced cell shrinkage followed by a regulatory volume increase, and cell alkalinization...

  9. F-actin distribution and function during sexual development in Eimeria maxima.

    Science.gov (United States)

    Frölich, Sonja; Wallach, Michael

    2015-06-01

    To determine the involvement of the actin cytoskeleton in macrogametocyte growth and oocyst wall formation, freshly purified macrogametocytes and oocysts were stained with Oregon Green 514 conjugated phalloidin to visualize F-actin microfilaments, while Evans blue staining was used to detect type 1 wall forming bodies (WFB1s) and the outer oocyst wall. The double-labelled parasites were then analysed at various stages of sexual development using three-dimensional confocal microscopy. The results showed F-actin filaments were distributed throughout the entire cytoplasm of mature Eimeria maxima macrogametocytes forming a web-like meshwork of actin filaments linking the type 1 WFBs together into structures resembling 'beads on a string'. At the early stages of oocyst wall formation, F-actin localization changed in alignment with the egg-shaped morphology of the forming oocysts with F-actin microfilaments making direct contact with the WFB1s. In tissue oocysts, the labelled actin cytoskeleton was situated underneath the forming outer layer of the oocyst wall. Treatment of macrogametocytes in vitro with the actin depolymerizing agents, Cytochalasin D and Latrunculin, led to a reduction in the numbers of mature WFB1s in the cytoplasm of the developing macrogametocytes, indicating that the actin plays an important role in WFB1 transport and oocyst wall formation in E. maxima.

  10. Quantitation of liquid-crystalline ordering in F-actin solutions.

    Science.gov (United States)

    Coppin, C M; Leavis, P C

    1992-09-01

    Actin filaments (F-actin) are important determinants of cellular shape and motility. These functions depend on the collective organization of numerous filaments with respect to both position and orientation in the cytoplasm. Much of the orientational organization arises spontaneously through liquid crystal formation in concentrated F-actin solutions. In studying this phenomenon, we found that solutions of purified F-actin undergo a continuous phase transition, from the isotropic state to a liquid crystalline state, when either the mean filament length or the actin concentration is increased above its respective threshold value. The phase diagram representing the threshold filament lengths and concentrations at which the phase transition occurs is consistent with that predicted by Flory's theory on solutions of noninteracting, rigid cylinders (Flory, 1956b). However, in contrast to other predictions based on this model, we found no evidence for the coexistence of isotropic and anisotropic phases. Furthermore, the phase transition proved to be temperature dependent, which suggests the existence of orientation-dependent interfilament interactions or of a temperature-dependent filament flexibility. We developed a simple method for growing undistorted fluorescent acrylodan-labeled F-actin liquid crystals; and we derived a simple theoretical treatment by which polarization-of-fluorescence measurements could be used to quantitate, for the first time, the degree of spontaneous filament ordering (nematic order parameter) in these F-actin liquid crystals. This order parameter was found to increase monotonically with both filament length and concentration. Actin liquid crystals can readily become distorted by a process known as "texturing." Zigzaging and helicoidal liquid crystalline textures which persisted in the absence of ATP were observed through the polarizing microscope. Possible texturing mechanisms are discussed.

  11. AKAP220 manages apical actin networks that coordinate aquaporin-2 location and renal water reabsorption.

    Science.gov (United States)

    Whiting, Jennifer L; Ogier, Leah; Forbush, Katherine A; Bucko, Paula; Gopalan, Janani; Seternes, Ole-Morten; Langeberg, Lorene K; Scott, John D

    2016-07-26

    Filtration through the kidney eliminates toxins, manages electrolyte balance, and controls water homeostasis. Reabsorption of water from the luminal fluid of the nephron occurs through aquaporin-2 (AQP2) water pores in principal cells that line the kidney-collecting duct. This vital process is impeded by formation of an "actin barrier" that obstructs the passive transit of AQP2 to the plasma membrane. Bidirectional control of AQP2 trafficking is managed by hormones and signaling enzymes. We have discovered that vasopressin-independent facets of this homeostatic mechanism are under the control of A-Kinase Anchoring Protein 220 (AKAP220; product of the Akap11 gene). CRISPR/Cas9 gene editing and imaging approaches show that loss of AKAP220 disrupts apical actin networks in organoid cultures. Similar defects are evident in tissue sections from AKAP220-KO mice. Biochemical analysis of AKAP220-null kidney extracts detected reduced levels of active RhoA GTPase, a well-known modulator of the actin cytoskeleton. Fluorescent imaging of kidney sections from these genetically modified mice revealed that RhoA and AQP2 accumulate at the apical surface of the collecting duct. Consequently, these animals are unable to appropriately dilute urine in response to overhydration. We propose that membrane-proximal signaling complexes constrained by AKAP220 impact the actin barrier dynamics and AQP2 trafficking to ensure water homeostasis.

  12. Drosophila Imp iCLIP identifies an RNA assemblage coordinating F-actin formation

    DEFF Research Database (Denmark)

    Hansen, Heidi Theil; Rasmussen, Simon Horskjær; Adolph, Sidsel Kramshøj;

    2015-01-01

    CLIP) technologies in Drosophila cells to identify transcripts associated with cytoplasmic ribonucleoproteins (RNPs) containing the RNA-binding protein Imp. RESULTS: We find extensive binding of Imp to 3'UTRs of transcripts that are involved in F-actin formation. A common denominator of the RNA-protein interface....... This demonstrates a physiological significance of the defined RNA regulon. CONCLUSIONS: Our data imply that Drosophila Imp RNPs may function as cytoplasmic mRNA assemblages that encode proteins which participate in actin cytoskeletal remodeling. Thus, they may facilitate co-ordinated protein expression in sub...... is the presence of multiple motifs with a central UA-rich element flanked by CA-rich elements. Experiments in single cells and intact flies reveal compromised actin cytoskeletal dynamics associated with low Imp levels. The former shows reduced F-actin formation and the latter exhibits abnormal neuronal patterning...

  13. Direct observation of motion of single F-actin filaments in the presence of myosin

    Science.gov (United States)

    Yanagida, Toshio; Nakase, Michiyuki; Nishiyama, Katsumi; Oosawa, Fumio

    1984-01-01

    Actin is found in almost all kinds of non-muscle cells where it is thought to have an important role in cell motility. A proper understanding of that role will only be possible when reliable in vitro systems are available for investigating the interaction of cellular actin and myosin. A start has been made on several systems1-4, most recently by Sheetz and Spudich who demonstrated unidirectional movement of HMM-coated beads along F-actin cables on arrays of chloroplasts exposed by dissection of a Nitella cell5. As an alternative approach, we report here the direct observation by fluorescence microscopy of the movements of single F-actin filaments interacting with soluble myosin fragments energized by Mg2+-ATP.

  14. Treatment of ras-induced cancers by the F-actin-bundling drug MKT-077.

    Science.gov (United States)

    Tikoo, A; Shakri, R; Connolly, L; Hirokawa, Y; Shishido, T; Bowers, B; Ye, L H; Kohama, K; Simpson, R J; Maruta, H

    2000-01-01

    A rhodacyanine dye called MKT-077 has shown a highly selective toxicity toward several distinct human malignant cell lines, including bladder carcinoma EJ, and has been subjected to clinical trials for cancer therapy. In the pancreatic carcinoma cell line CRL-1420, but not in normal African green monkey kidney cell line CV-1, it is selectively accumulated in mitochondria. However, both the specific oncogenes responsible for its selective toxicity toward cancer cells, and its target proteins in these cancer cells, still remain to be determined. This study was conducted using normal and ras-transformed NIH 3T3 fibroblasts to determine whether oncogenic ras mutants such as v-Ha-ras are responsible for the selective toxicity of MKT-077 and also to identify its targets, using its derivative called "compound 1" as a specific ligand. We have found that v-Ha-ras is responsible for the selective toxicity of MKT-077 in both in vitro and in vivo. Furthermore, we have identified and affinity purified at least two distinct proteins of 45 kD (p45) and 75 kD (p75), which bind MKT-077 in v-Ha-ras-transformed cells but not in parental normal cells. Microsequencing analysis has revealed that the p45 is a mixture of beta- and gamma-actin, whereas the p75 is HSC70, a constitutive member of the Hsp70 heat shock adenosine triphosphatase family, which inactivates the tumor suppressor p53. MKT-077 binds actin directly, bundles actin filaments by cross-linking, and blocks membrane ruffling. Like a few F-actin-bundling proteins such as HS1, alpha-actinin, and vinculin as well as F-actin cappers such as tensin and chaetoglobosin K (CK), the F-actin-bundling drug MKT-077 suppresses ras transformation by blocking membrane ruffling. These findings suggest that other selective F-actin-bundling/capping compounds are also potentially useful for the chemotherapy of ras-associated cancers.

  15. Comparative in vitro phagocytosis and F-actin polymerization of bovine neonatal neutrophils.

    Science.gov (United States)

    Moiola, F; Spycher, M; Wyder-Walther, M; Zwahlen, R D

    1994-04-01

    Analysis of neonatal neutrophil (PMN) functions should help to reveal factors which could contribute to the impaired host defense system of neonates. We analysed functional parameters of PMN from newborn calves (N-PMN) and adult bovines (A-PMN): cellular volume and F-actin content upon stimulation with complement factors, by cytofluorometry and phagocytosis of E. coli 78:80B with a colorimetric assay. Polymerization of F-actin was rapid in both N- and A-PMN, but reached higher levels in N-PMN. N-PMN are significantly smaller than A-PMN throughout the whole activation time. Percentage of phagocytosing PMN, the rate of phagocytosis, and the rate of killing are similar between A- and N-PMN after opsonization of bacteria with adult serum (AS). Opsonization with newborn serum (NS) reduced all three examined parameters: in A-PMN more (P dexamethasone) and non-steroidal (phenylbutazone) anti-inflammatory drugs inhibited phagocytosis by N-PMN less than by A-PMN. Higher relative F-actin content of N-PMN can be correlated with the documented functional hyperactivity of bovine N-PMN. However, the exaggerated impairment of phagocytosis in calves observed after age-matched opsonization of bacteria could potentially indicate a specific host defence defect.

  16. Dual chemotaxis signalling regulates Dictyostelium development: intercellular cyclic AMP pulses and intracellular F-actin disassembly waves induce each other.

    Science.gov (United States)

    Vicker, Michael G; Grutsch, James F

    2008-10-01

    Aggregating Dictyostelium discoideum amoebae periodically emit and relay cAMP, which regulates their chemotaxis and morphogenesis into a multicellular, differentiated organism. Cyclic AMP also stimulates F-actin assembly and chemotactic pseudopodium extension. We used actin-GFP expression to visualise for the first time intracellular F-actin assembly as a spatio-temporal indicator of cell reactions to cAMP, and thus the kinematics of cell communication, in aggregating streams. Every natural cAMP signal pulse induces an autowave of F-actin disassembly, which propagates from each cell's leading end to its trailing end at a linear rate, much slower than the calculated and measured velocities of cAMP diffusion in aggregating Dictyostelium. A sequence of transient reactions follows behind the wave, including anterior F-actin assembly, chemotactic pseudopodium extension and cell advance at the cell front and, at the back, F-actin assembly, extension of a small retrograde pseudopodium (forcing a brief cell retreat) and chemotactic stimulation of the following cell, yielding a 20s cAMP relay delay. These dynamics indicate that stream cell behaviour is mediated by a dual signalling system: a short-range cAMP pulse directed from one cell tail to an immediately following cell front and a slower, long-range wave of intracellular F-actin disassembly, each inducing the other.

  17. Cyclase-associated protein (CAP) acts directly on F-actin to accelerate cofilin-mediated actin severing across the range of physiological pH.

    Science.gov (United States)

    Normoyle, Kieran P M; Brieher, William M

    2012-10-12

    Fast actin depolymerization is necessary for cells to rapidly reorganize actin filament networks. Utilizing a Listeria fluorescent actin comet tail assay to monitor actin disassembly rates, we observed that although a mixture of actin disassembly factors (cofilin, coronin, and actin-interacting protein 1 is sufficient to disassemble actin comet tails in the presence of physiological G-actin concentrations this mixture was insufficient to disassemble actin comet tails in the presence of physiological F-actin concentrations. Using biochemical complementation, we purified cyclase-associated protein (CAP) from thymus extracts as a factor that protects against the inhibition of excess F-actin. CAP has been shown to participate in actin dynamics but has been thought to act by liberating cofilin from ADP·G-actin monomers to restore cofilin activity. However, we found that CAP augments cofilin-mediated disassembly by accelerating the rate of cofilin-mediated severing. We also demonstrated that CAP acts directly on F-actin and severs actin filaments at acidic, but not neutral, pH. At the neutral pH characteristic of cytosol in most mammalian cells, we demonstrated that neither CAP nor cofilin are capable of severing actin filaments. However, the combination of CAP and cofilin rapidly severed actin at all pH values across the physiological range. Therefore, our results reveal a new function for CAP in accelerating cofilin-mediated actin filament severing and provide a mechanism through which cells can maintain high actin turnover rates without having to alkalinize cytosol, which would affect many biochemical reactions beyond actin depolymerization.

  18. An atomic model of the tropomyosin cable on F-actin.

    Science.gov (United States)

    Orzechowski, Marek; Li, Xiaochuan Edward; Fischer, Stefan; Lehman, William

    2014-08-05

    Tropomyosin regulates a wide variety of actin filament functions and is best known for the role that it plays together with troponin in controlling muscle activity. For effective performance on actin filaments, adjacent 42-nm-long tropomyosin molecules are joined together by a 9- to 10-residue head-to-tail overlapping domain to form a continuous cable that wraps around the F-actin helix. Yet, despite the apparent simplicity of tropomyosin's coiled-coil structure and its well-known periodic association with successive actin subunits along F-actin, the structure of the tropomyosin cable on actin is uncertain. This is because the conformation of the overlap region that joins neighboring molecules is poorly understood, thus leaving a significant gap in our understanding of thin-filament structure and regulation. However, recent molecular-dynamics simulations of overlap segments defined their overall shape and provided unique and sufficient cues to model the whole actin-tropomyosin filament assembly in atomic detail. In this study, we show that these MD structures merge seamlessly onto the ends of tropomyosin coiled-coils. Adjacent tropomyosin molecules can then be joined together to provide a comprehensive model of the tropomyosin cable running continuously on F-actin. The resulting complete model presented here describes for the first time (to our knowledge) an atomic-level structure of αα-striated muscle tropomyosin bound to an actin filament that includes the critical overlap domain. Thus, the model provides a structural correlate to evaluate thin-filament mechanics, self-assembly mechanisms, and the effect of disease-causing mutations.

  19. F-actin-like filaments formed by plasmid segregation protein ParM

    DEFF Research Database (Denmark)

    van den Ent, Fusinita; Møller-Jensen, Jakob; Amos, Linda A.;

    2002-01-01

    It was the general belief that DNA partitioning in prokaryotes is independent of a cytoskeletal structure, which in eukaryotic cells is indispensable for DNA segregation. Recently, however, immunofluorescence microscopy revealed highly dynamic, filamentous structures along the longitudinal axis...... of Escherichia coli formed by ParM, a plasmid-encoded protein required for accurate segregation of low-copy-number plasmid R1. We show here that ParM polymerizes into double helical protofilaments with a longitudinal repeat similar to filamentous actin (F-actin) and MreB filaments that maintain the cell shape...

  20. Fluorescence studies of the carboxyl-terminal domain of smooth muscle calponin effects of F-actin and salts.

    Science.gov (United States)

    Bartegi, A; Roustan, C; Kassab, R; Fattoum, A

    1999-06-01

    The fluorescence parameters of the environment-sensitive acrylodan, selectively attached to Cys273 in the C-terminal domain of smooth muscle calponin, were studied in the presence of F-actin and using varying salt concentrations. The formation of the F-actin acrylodan labeled calponin complex at 75 mm NaCl resulted in a 21-nm blue shift of the maximum emission wavelength from 496 nm to 474 nm and a twofold increase of the fluorescent quantum yield at 460 nm. These spectral changes were observed at the low ionic strengths ( 110 mm) where the binding stoichiometry is a 1 : 2 ratio of calponin : actin monomers. On the basis of previous three-dimensional reconstruction and chemical crosslinking of the F-actin-calponin complex, the actin effect is shown to derive from the low ionic strength interaction of calponin with the bottom of subdomain-1 of an upper actin monomer in F-actin and not from its further association with the subdomain-1 of the adjacent lower monomer which occurs at the high ionic strength. Remarkably, the F-actin-dependent fluorescence change of acrylodan is qualitatively but not quantitatively similar to that earlier reported for the complexes of calponin and Ca2+-calmodulin or Ca2+-caltropin. As the three calponin ligands bind to the same segment of the protein, encompassing residues 145-182, the acrylodan can be considered as a sensitive probe of the functioning of this critical region. A distance of 29 A was measured by fluorescence resonance energy transfer between Cys273 of calponin and Cys374 of actin in the 1 : 1 F-actin-calponin complex suggesting that the F-actin effect was allosteric reflecting a global conformational change in the C-terminal domain of calponin.

  1. Purification from Acanthamoeba castellanii of proteins that induce gelation and syneresis of F-actin.

    Science.gov (United States)

    Maruta, H; Korn, E D

    1977-01-10

    From Acanthamoeba castellanii, we have purified four proteins each of which alone causes a solution of F-actin to gel. The four active proteins have subunit molecular weights of about 23,000, 28,000, 32,000 and 38,000, respectively; the last three may be dimers in their native proteins. Together, these four proteins account for about 97% of the gelation activity of the whole extract; not more than about 3% of the total activity of the unfractionated extract can be due to a 250,000-dalton polypeptide. Another protein fraction, purified by agarose chromatography, induces shrinking (syneresis) of gels formed from F-actin and any of the gelation factors. That fraction contains a high Ca2+-, low (K+,EDTA)-ATPase and a major polypeptide of 170,000 daltons both of which bind to actin in the shrunken gel pellet. The active fraction does not contain the previously described Acanthamoeba myosin (Pollard, T. D., and Korn, E. D. (1973) J. Biol. Chem. 248, 4682-4690).

  2. Mechanosensitive channel activity and F-actin organization in cholesterol-depleted human leukaemia cells.

    Science.gov (United States)

    Morachevskaya, Elena; Sudarikova, Anastasiya; Negulyaev, Yuri

    2007-04-01

    This study focuses on the functional role of cellular cholesterol in the regulation of mechanosensitive cation channels activated by stretch in human leukaemia K562 cells. The patch-clamp method was employed to examine the effect of methyl-beta-cyclodextrin (MbetaCD), a synthetic cholesterol-sequestering agent, on stretch-activated single currents. We found that cholesterol-depleting treatment with MbetaCD resulted in a suppression of the activity of mechanosensitive channels without a change in the unitary conductance. The probability that the channel was open significantly decreased after treatment with MbetaCD. Fluorescent microscopy revealed F-actin reorganization, possibly involving actin assembly, after incubation of the cells with MbetaCD. We suggest that suppression of mechanosensitive channel activation in cholesterol-depleted leukaemia cells is due to F-actin rearrangement, presumably induced by lipid raft destruction. Our observations are consistent with the notion that stretch-activated cation channels in eukaryotic cells are regulated by the membrane-cytoskeleton complex rather than by tension developed purely in the lipid bilayer.

  3. F-actin-binding protein drebrin regulates CXCR4 recruitment to the immune synapse.

    Science.gov (United States)

    Pérez-Martínez, Manuel; Gordón-Alonso, Mónica; Cabrero, José Román; Barrero-Villar, Marta; Rey, Mercedes; Mittelbrunn, María; Lamana, Amalia; Morlino, Giulia; Calabia, Carmen; Yamazaki, Hiroyuki; Shirao, Tomoaki; Vázquez, Jesús; González-Amaro, Roberto; Veiga, Esteban; Sánchez-Madrid, Francisco

    2010-04-01

    The adaptive immune response depends on the interaction of T cells and antigen-presenting cells at the immune synapse. Formation of the immune synapse and the subsequent T-cell activation are highly dependent on the actin cytoskeleton. In this work, we describe that T cells express drebrin, a neuronal actin-binding protein. Drebrin colocalizes with the chemokine receptor CXCR4 and F-actin at the peripheral supramolecular activation cluster in the immune synapse. Drebrin interacts with the cytoplasmic tail of CXCR4 and both proteins redistribute to the immune synapse with similar kinetics. Drebrin knockdown in T cells impairs the redistribution of CXCR4 and inhibits actin polymerization at the immune synapse as well as IL-2 production. Our data indicate that drebrin exerts an unexpected and relevant functional role in T cells during the generation of the immune response.

  4. Control of electrostatic interactions between F-actin and genetically modified lysozyme in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Lori K.; Xian, Wujing; Guaqueta, Camilo; Strohman, Michael J.; Vrasich, Chuck R.; Luijten, Erik; Wong, Gerard C.L. (UIUC)

    2008-07-11

    The aim for deterministic control of the interactions between macroions in aqueous media has motivated widespread experimental and theoretical work. Although it has been well established that like-charged macromolecules can aggregate under the influence of oppositely charged condensing agents, the specific conditions for the stability of such aggregates can only be determined empirically. We examine these conditions, which involve an interplay of electrostatic and osmotic effects, by using a well defined model system composed of F-actin, an anionic rod-like polyelectrolyte, and lysozyme, a cationic globular protein with a charge that can be genetically modified. The structure and stability of actin-lysozyme complexes for different lysozyme charge mutants and salt concentrations are examined by using synchrotron x-ray scattering and molecular dynamics simulations. We provide evidence that supports a structural transition from columnar arrangements of F-actin held together by arrays of lysozyme at the threefold interstitial sites of the actin sublattice to marginally stable complexes in which lysozyme resides at twofold bridging sites between actin. The reduced stability arises from strongly reduced partitioning of salt between the complex and the surrounding solution. Changes in the stability of actin-lysozyme complexes are of biomedical interest because their formation has been reported to contribute to the persistence of airway infections in cystic fibrosis by sequestering antimicrobials such as lysozyme. We present x-ray microscopy results that argue for the existence of actin-lysozyme complexes in cystic fibrosis sputum and demonstrate that, for a wide range of salt conditions, charge-reduced lysozyme is not sequestered in ordered complexes while retaining its bacterial killing activity.

  5. Control of Electrostatic Interactions Between F-Actin And Genetically Modified Lysozyme in Aqueous Media

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, L.K.; Xian, W.; Guaqueta, C.; Strohman, M.; Vrasich, C.R.; Luijten, E.; Wong, G.C.L.

    2009-06-04

    The aim for deterministic control of the interactions between macroions in aqueous media has motivated widespread experimental and theoretical work. Although it has been well established that like-charged macromolecules can aggregate under the influence of oppositely charged condensing agents, the specific conditions for the stability of such aggregates can only be determined empirically. We examine these conditions, which involve an interplay of electrostatic and osmotic effects, by using a well defined model system composed of F-actin, an anionic rod-like polyelectrolyte, and lysozyme, a cationic globular protein with a charge that can be genetically modified. The structure and stability of actin-lysozyme complexes for different lysozyme charge mutants and salt concentrations are examined by using synchrotron x-ray scattering and molecular dynamics simulations. We provide evidence that supports a structural transition from columnar arrangements of F-actin held together by arrays of lysozyme at the threefold interstitial sites of the actin sublattice to marginally stable complexes in which lysozyme resides at twofold bridging sites between actin. The reduced stability arises from strongly reduced partitioning of salt between the complex and the surrounding solution. Changes in the stability of actin-lysozyme complexes are of biomedical interest because their formation has been reported to contribute to the persistence of airway infections in cystic fibrosis by sequestering antimicrobials such as lysozyme. We present x-ray microscopy results that argue for the existence of actin-lysozyme complexes in cystic fibrosis sputum and demonstrate that, for a wide range of salt conditions, charge-reduced lysozyme is not sequestered in ordered complexes while retaining its bacterial killing activity.

  6. Regulation of retinoschisin secretion in Weri-Rb1 cells by the F-actin and microtubule cytoskeleton.

    Directory of Open Access Journals (Sweden)

    Eiko Kitamura

    Full Text Available Retinoschisin is encoded by the gene responsible for X-linked retinoschisis (XLRS, an early onset macular degeneration that results in a splitting of the inner layers of the retina and severe loss in vision. Retinoschisin is predominantly expressed and secreted from photoreceptor cells as a homo-oligomer protein; it then associates with the surface of retinal cells and maintains the retina cellular architecture. Many missense mutations in the XLRS1 gene are known to cause intracellular retention of retinoschisin, indicating that the secretion process of the protein is a critical step for its normal function in the retina. However, the molecular mechanisms underlying retinoschisin's secretion remain to be fully elucidated. In this study, we investigated the role of the F-actin cytoskeleton in the secretion of retinoschisin by treating Weri-Rb1 cells, which are known to secrete retinoschisin, with cytochalasin D, jasplakinolide, Y-27632, and dibutyryl cGMP. Our results show that cytochalasin D and jasplakinolide inhibit retinoschisin secretion, whereas Y-27632 and dibutyryl cGMP enhance secretion causing F-actin alterations. We also demonstrate that high concentrations of taxol, which hyperpolymerizes microtubules, inhibit retinoschisin secretion. Our data suggest that retinoschisin secretion is regulated by the F-actin cytoskeleton, that cGMP or inhibition of ROCK alters F-actin structure enhancing the secretion, and that the microtubule cytoskeleton is also involved in this process.

  7. Clinical and biologic importance of F-actin autoantibodies in HCV monoinfected and HCV-HIV coinfected patients.

    Science.gov (United States)

    Hudacko, Rachel M; Alvarez, Gustavo A; Talal, Andrew H; Jacobson, Ira; Wan, David W; Zhou, Xi K; Yantiss, Rhonda K

    2010-08-01

    The purpose of this study was to evaluate the relationship between serum filamentous (F)-actin antibody titers and severity of hepatitis present in hepatitis C virus (HCV)-infected patients. Liver biopsy samples from 18 HCV monoinfected and 20 HCV-HIV coinfected patients were graded with respect to the degree of hepatitis activity and intensity of plasma cell infiltration using MUM-1 and CD138 immunostains. Of the 38 HCV-infected patients, 6 (16%) had F-actin antibody titers in excess of 30 enzyme-linked immunosorbent assay units. We found a positive trend between serum F-actin antibody levels and the mean number of plasma cells present in the portal tracts of patients with HCV infection (r = 0.31; P = .06) and a significant association between these factors in HCV-HIV coinfected patients (r = 0.64; P = .002). Our data suggest that elevated serum F-actin antibody titers are commonly encountered in HCV-infected patients and may reflect more active inflammation in liver biopsy samples, similar to autoimmune hepatitis.

  8. Comparative genome analysis of cortactin and HSI : the significance of the F-actin binding repeat domain

    NARCIS (Netherlands)

    van Rossum, AGSH; Schuuring-Scholtes, E; Seggelen, VV; Kluin, PM; Schuuring, E

    2005-01-01

    Background: In human carcinomas, overexpression of cortactin correlates with poor prognosis. Cortactin is an F-actin-binding protein involved in cytoskeletal rearrangements and cell migration by promoting actin-related protein (Arp)2/3 mediated actin polymerization. It shares a high amino acid seque

  9. The F-actin modifier villin regulates insulin granule dynamics and exocytosis downstream of islet cell autoantigen 512

    Directory of Open Access Journals (Sweden)

    Hassan Mziaut

    2016-08-01

    Conclusion: Our findings show that villin controls the size of the F-actin cages restricting SGs and, thus, regulates their dynamics and availability for exocytosis. Evidence that villin acts downstream of Ica512 also indicates that SGs directly influence the remodeling properties of the cortical actin cytoskeleton for tight control of insulin secretion.

  10. Prickle/spiny-legs isoforms control the polarity of the apical microtubule network in planar cell polarity.

    Science.gov (United States)

    Olofsson, Jessica; Sharp, Katherine A; Matis, Maja; Cho, Bomsoo; Axelrod, Jeffrey D

    2014-07-01

    Microtubules (MTs) are substrates upon which plus- and minus-end directed motors control the directional movement of cargos that are essential for generating cell polarity. Although centrosomal MTs are organized with plus-ends away from the MT organizing center, the regulation of non-centrosomal MT polarity is poorly understood. Increasing evidence supports the model that directional information for planar polarization is derived from the alignment of a parallel apical network of MTs and the directional MT-dependent trafficking of downstream signaling components. The Fat/Dachsous/Four-jointed (Ft/Ds/Fj) signaling system contributes to orienting those MTs. In addition to previously defined functions in promoting asymmetric subcellular localization of 'core' planar cell polarity (PCP) proteins, we find that alternative Prickle (Pk-Sple) protein isoforms control the polarity of this MT network. This function allows the isoforms of Pk-Sple to differentially determine the direction in which asymmetry is established and therefore, ultimately, the direction of tissue polarity. Oppositely oriented signals that are encoded by oppositely oriented Fj and Ds gradients produce the same polarity outcome in different tissues or compartments, and the tissue-specific activity of alternative Pk-Sple protein isoforms has been observed to rectify the interpretation of opposite upstream directional signals. The control of MT polarity, and thus the directionality of apical vesicle traffic, by Pk-Sple provides a mechanism for this rectification.

  11. Apical cap

    Energy Technology Data Exchange (ETDEWEB)

    McLoud, T.C.; Isler, R.J.; Novelline, R.A.; Putman, C.E.; Simeone, J.; Stark, P.

    1981-08-01

    Apical caps, either unilateral or bilateral, are a common feature of advancing age and are usually the result of subpleural scarring unassociated with other diseases. Pancoast (superior sulcus) tumors are a well recognized cause of unilateral asymmetric apical density. Other lesions arising in the lung, pleura, or extrapleural space may produce unilateral or bilateral apical caps. These include: (1) inflammatory: tuberculosis and extrapleural abscesses extending from the neck; (2) post radiation fibrosis after mantle therapy for Hodgkin disease or supraclavicular radiation in the treatment of breast carcinoma; (3) neoplasm: lymphoma extending from the neck or mediastinum, superior sulcus bronchogenic carcinoma, and metastases; (4) traumatic: extrapleural dissection of blood from a ruptured aorta, fractures of the ribs or spine, or hemorrhage due to subclavian line placement; (5) vascular: coarctation of the aorta with dilated collaterals over the apex, fistula between the subclavian artery and vein; and (6) miscellaneous: mediastinal lipomatosis with subcostal fat extending over the apices.

  12. A gene regulatory network for apical organ neurogenesis and its spatial control in sea star embryos.

    Science.gov (United States)

    Cheatle Jarvela, Alys M; Yankura, Kristen A; Hinman, Veronica F

    2016-11-15

    How neural stem cells generate the correct number and type of differentiated neurons in appropriate places remains an important question. Although nervous systems are diverse across phyla, in many taxa the larva forms an anterior concentration of serotonergic neurons, or apical organ. The sea star embryo initially has a pan-neurogenic ectoderm, but the genetic mechanism that directs a subset of these cells to generate serotonergic neurons in a particular location is unresolved. We show that neurogenesis in sea star larvae begins with soxc-expressing multipotent progenitors. These give rise to restricted progenitors that express lhx2/9 soxc- and lhx2/9-expressing cells can undergo both asymmetric divisions, allowing for progression towards a particular neural fate, and symmetric proliferative divisions. We show that nested concentric domains of gene expression along the anterior-posterior (AP) axis, which are observed in a great diversity of metazoans, control neurogenesis in the sea star larva by promoting particular division modes and progression towards becoming a neuron. This work explains how spatial patterning in the ectoderm controls progression of neurogenesis in addition to providing spatial cues for neuron location. Modification to the sizes of these AP territories provides a simple mechanism to explain the diversity of neuron number among apical organs.

  13. Rheological characterization of the bundling transition in F-actin solutions induced by methylcellulose.

    Directory of Open Access Journals (Sweden)

    Simone Köhler

    Full Text Available In many in vitro experiments Brownian motion hampers quantitative data analysis. Therefore, additives are widely used to increase the solvent viscosity. For this purpose, methylcellulose (MC has been proven highly effective as already small concentrations can significantly slow down diffusive processes. Beside this advantage, it has already been reported that high MC concentrations can alter the microstructure of polymer solutions such as filamentous actin. However, it remains to be shown to what extent the mechanical properties of a composite actin/MC gel depend on the MC concentration. In particular, significant alterations might occur even if the microstructure seems unaffected. Indeed, we find that the viscoelastic response of entangled F-actin solutions depends sensitively on the amount of MC added. At concentrations higher than 0.2% (w/v MC, actin filaments are reorganized into bundles which drastically changes the viscoelastic response. At small MC concentrations the impact of MC is more subtle: the two constituents, actin and MC, contribute in an additive way to the mechanical response of the composite material. As a consequence, the effect of methylcellulose on actin solutions has to be considered very carefully when MC is used in biochemical experiments.

  14. Comparative genome analysis of cortactin and HS1: the significance of the F-actin binding repeat domain

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    Seggelen Vera

    2005-02-01

    Full Text Available Abstract Background In human carcinomas, overexpression of cortactin correlates with poor prognosis. Cortactin is an F-actin-binding protein involved in cytoskeletal rearrangements and cell migration by promoting actin-related protein (Arp2/3 mediated actin polymerization. It shares a high amino acid sequence and structural similarity to hematopoietic lineage cell-specific protein 1 (HS1 although their functions differ considerable. In this manuscript we describe the genomic organization of these two genes in a variety of species by a combination of cloning and database searches. Based on our analysis, we predict the genesis of the actin-binding repeat domain during evolution. Results Cortactin homologues exist in sponges, worms, shrimps, insects, urochordates, fishes, amphibians, birds and mammalians, whereas HS1 exists in vertebrates only, suggesting that both genes have been derived from an ancestor cortactin gene by duplication. In agreement with this, comparative genome analysis revealed very similar exon-intron structures and sequence homologies, especially over the regions that encode the characteristic highly conserved F-actin-binding repeat domain. Cortactin splice variants affecting this F-actin-binding domain were identified not only in mammalians, but also in amphibians, fishes and birds. In mammalians, cortactin is ubiquitously expressed except in hematopoietic cells, whereas HS1 is mainly expressed in hematopoietic cells. In accordance with their distinct tissue specificity, the putative promoter region of cortactin is different from HS1. Conclusions Comparative analysis of the genomic organization and amino acid sequences of cortactin and HS1 provides inside into their origin and evolution. Our analysis shows that both genes originated from a gene duplication event and subsequently HS1 lost two repeats, whereas cortactin gained one repeat. Our analysis genetically underscores the significance of the F-actin binding domain in

  15. A human β-III-spectrin spinocerebellar ataxia type 5 mutation causes high-affinity F-actin binding

    Science.gov (United States)

    Avery, Adam W.; Crain, Jonathan; Thomas, David D.; Hays, Thomas S.

    2016-01-01

    Spinocerebellar ataxia type 5 (SCA5) is a human neurodegenerative disease that stems from mutations in the SPTBN2 gene encoding the protein β-III-spectrin. Here we investigated the molecular consequence of a SCA5 missense mutation that results in a L253P substitution in the actin-binding domain (ABD) of β-III-spectrin. We report that the L253P substitution in the isolated β-III-spectrin ABD causes strikingly high F-actin binding affinity (Kd = 75.5 nM) compared to the weak F-actin binding affinity of the wild-type ABD (Kd = 75.8 μM). The mutation also causes decreased thermal stability (Tm = 44.6 °C vs 59.5 °C). Structural analyses indicate that leucine 253 is in a loop at the interface of the tandem calponin homology (CH) domains comprising the ABD. Leucine 253 is predicted to form hydrophobic contacts that bridge the CH domains. The decreased stability of the mutant indicates that these bridging interactions are probably disrupted, suggesting that the high F-actin binding affinity of the mutant is due to opening of the CH domain interface. These results support a fundamental role for leucine 253 in regulating opening of the CH domain interface and binding of the ABD to F-actin. This study indicates that high-affinity actin binding of L253P β-III-spectrin is a likely driver of neurodegeneration. PMID:26883385

  16. Effect of Leflunomide on the Abnormal Expression of Lipid Rafts and F-Actin in B Lymphocytes from Patients with Systemic Lupus Erythematosus

    Directory of Open Access Journals (Sweden)

    Guang Fu Dong

    2015-01-01

    Full Text Available Purposes. To investigate the possible changes in B cell subsets and in B cell expression patterns of lipid rafts (LRs and F-actin in patients with SLE and whether leflunomide treatment may have effect on these changes. Methods. The B cell subsets and LRs expression were determined by flow cytometry and confocal microscopy, and F-actin expression was examined by confocal microscopy. Results. CD27+IgD+ B cell subsets were significantly decreased while CD38+CD95+ B cell subsets increased in SLE patients. The LRs levels of B cells were remarkably increased and positively correlated with SLEDAI and anti-dsDNA titer in SLE patients. The expression level of LRs was significantly higher in CD38+ B cells than CD38− B cells and negatively correlated with C3 levels. The increased expression of LRs was associated with reduced expression of F-actin in the B cells from active SLE patients. Furthermore, in vitro treatment of the cells with A771726 reduced the expression level of LRs, attenuated the overaggregation of LRs, and normalized the distribution of F-actin. Conclusions. There were abnormalities in B cell subsets and LRs and F-actin expression of B cell from SLE patients. Modulation of B cell expression of LRs and F-actin by LEF could be a potential therapeutic target for SLE.

  17. Nuclear F-actin enhances the transcriptional activity of β-catenin by increasing its nuclear localization and binding to chromatin.

    Science.gov (United States)

    Yamazaki, Shota; Yamamoto, Koji; de Lanerolle, Primal; Harata, Masahiko

    2016-04-01

    Actin plays multiple roles both in the cytoplasm and in the nucleus. Cytoplasmic actin, in addition to its structural role in the cytoskeleton, also contributes to the subcellular localization of transcription factors by interacting with them or their partners. The transcriptional cofactor β-catenin, which acts as an intracellular transducer of canonical Wnt signaling, indirectly associates with the cytoplasmic filamentous actin (F-actin). Recently, it has been observed that F-actin is transiently formed within the nucleus in response to serum stimulation and integrin signaling, and also during gene reprogramming. Despite these earlier observations, information about the function of nuclear F-actin is poorly defined. Here, by facilitating the accumulation of nuclear actin artificially, we demonstrate that polymerizing nuclear actin enhanced the nuclear accumulation and transcriptional function of β-catenin. Our results also show that the nuclear F-actin colocalizes with β-catenin and enhances the binding of β-catenin to the downstream target genes of the Wnt/β-catenin signaling pathway, including the genes for the cell cycle regulators c-myc and cyclin D, and the OCT4 gene. Nuclear F-actin itself also associated with these genes. Since Wnt/β-catenin signaling has important roles in cell differentiation and pluripotency, our observations suggest that nuclear F-actin formed during these biological processes is involved in regulating Wnt/β-catenin signaling.

  18. Live imaging provides new insights on dynamic F-actin filopodia and differential endocytosis during myoblast fusion in Drosophila.

    Directory of Open Access Journals (Sweden)

    Shruti Haralalka

    Full Text Available The process of myogenesis includes the recognition, adhesion, and fusion of committed myoblasts into multinucleate syncytia. In the larval body wall muscles of Drosophila, this elaborate process is initiated by Founder Cells and Fusion-Competent Myoblasts (FCMs, and cell adhesion molecules Kin-of-IrreC (Kirre and Sticks-and-stones (Sns on their respective surfaces. The FCMs appear to provide the driving force for fusion, via the assembly of protrusions associated with branched F-actin and the WASp, SCAR and Arp2/3 pathways. In the present study, we utilize the dorsal pharyngeal musculature that forms in the Drosophila embryo as a model to explore myoblast fusion and visualize the fusion process in live embryos. These muscles rely on the same cell types and genes as the body wall muscles, but are amenable to live imaging since they do not undergo extensive morphogenetic movement during formation. Time-lapse imaging with F-actin and membrane markers revealed dynamic FCM-associated actin-enriched protrusions that rapidly extend and retract into the myotube from different sites within the actin focus. Ultrastructural analysis of this actin-enriched area showed that they have two morphologically distinct structures: wider invasions and/or narrow filopodia that contain long linear filaments. Consistent with this, formin Diaphanous (Dia and branched actin nucleator, Arp3, are found decorating the filopodia or enriched at the actin focus, respectively, indicating that linear actin is present along with branched actin at sites of fusion in the FCM. Gain-of-function Dia and loss-of-function Arp3 both lead to fusion defects, a decrease of F-actin foci and prominent filopodia from the FCMs. We also observed differential endocytosis of cell surface components at sites of fusion, with actin reorganizing factors, WASp and SCAR, and Kirre remaining on the myotube surface and Sns preferentially taken up with other membrane proteins into early endosomes and

  19. Live imaging provides new insights on dynamic F-actin filopodia and differential endocytosis during myoblast fusion in Drosophila.

    Science.gov (United States)

    Haralalka, Shruti; Shelton, Claude; Cartwright, Heather N; Guo, Fengli; Trimble, Rhonda; Kumar, Ram P; Abmayr, Susan M

    2014-01-01

    The process of myogenesis includes the recognition, adhesion, and fusion of committed myoblasts into multinucleate syncytia. In the larval body wall muscles of Drosophila, this elaborate process is initiated by Founder Cells and Fusion-Competent Myoblasts (FCMs), and cell adhesion molecules Kin-of-IrreC (Kirre) and Sticks-and-stones (Sns) on their respective surfaces. The FCMs appear to provide the driving force for fusion, via the assembly of protrusions associated with branched F-actin and the WASp, SCAR and Arp2/3 pathways. In the present study, we utilize the dorsal pharyngeal musculature that forms in the Drosophila embryo as a model to explore myoblast fusion and visualize the fusion process in live embryos. These muscles rely on the same cell types and genes as the body wall muscles, but are amenable to live imaging since they do not undergo extensive morphogenetic movement during formation. Time-lapse imaging with F-actin and membrane markers revealed dynamic FCM-associated actin-enriched protrusions that rapidly extend and retract into the myotube from different sites within the actin focus. Ultrastructural analysis of this actin-enriched area showed that they have two morphologically distinct structures: wider invasions and/or narrow filopodia that contain long linear filaments. Consistent with this, formin Diaphanous (Dia) and branched actin nucleator, Arp3, are found decorating the filopodia or enriched at the actin focus, respectively, indicating that linear actin is present along with branched actin at sites of fusion in the FCM. Gain-of-function Dia and loss-of-function Arp3 both lead to fusion defects, a decrease of F-actin foci and prominent filopodia from the FCMs. We also observed differential endocytosis of cell surface components at sites of fusion, with actin reorganizing factors, WASp and SCAR, and Kirre remaining on the myotube surface and Sns preferentially taken up with other membrane proteins into early endosomes and lysosomes in the

  20. G protein-coupled receptors engage the mammalian Hippo pathway through F-actin: F-Actin, assembled in response to Galpha12/13 induced RhoA-GTP, promotes dephosphorylation and activation of the YAP oncogene.

    Science.gov (United States)

    Regué, Laura; Mou, Fan; Avruch, Joseph

    2013-05-01

    The Hippo pathway, a cascade of protein kinases that inhibits the oncogenic transcriptional coactivators YAP and TAZ, was discovered in Drosophila as a major determinant of organ size in development. Known modes of regulation involve surface proteins that mediate cell-cell contact or determine epithelial cell polarity which, in a tissue-specific manner, use intracellular complexes containing FERM domain and actin-binding proteins to modulate the kinase activities or directly sequester YAP. Unexpectedly, recent work demonstrates that GPCRs, especially those signaling through Galpha12/13 such as the protease activated receptor PAR1, cause potent YAP dephosphorylation and activation. This response requires active RhoA GTPase and increased assembly of filamentous (F-)actin. Morever, cell architectures that promote F-actin assembly per se also activate YAP by kinase-dependent and independent mechanisms. These findings unveil the ability of GPCRs to activate the YAP oncogene through a newly recognized signaling function of the actin cytoskeleton, likely to be especially important for normal and cancerous stem cells.

  1. Binding of the N-terminal fragment C0-C2 of cardiac MyBP-C to cardiac F-actin.

    Science.gov (United States)

    Kensler, Robert W; Shaffer, Justin F; Harris, Samantha P

    2011-04-01

    Cardiac myosin-binding protein C (cMyBP-C), a major accessory protein of cardiac thick filaments, is thought to play a key role in the regulation of myocardial contraction. Although current models for the function of the protein focus on its binding to myosin S2, other evidence suggests that it may also bind to F-actin. We have previously shown that the N-terminal fragment C0-C2 of cardiac myosin-binding protein-C (cMyBP-C) bundles actin, providing evidence for interaction of cMyBP-C and actin. In this paper we directly examined the interaction between C0-C2 and F-actin at physiological ionic strength and pH by negative staining and electron microscopy. We incubated C0-C2 (5-30μM, in a buffer containing in mM: 180 KCl, 1 MgCl(2), 1 EDTA, 1 DTT, 20 imidazole, at pH 7.4) with F-actin (5μM) for 30min and examined negatively-stained samples of the solution by electron microscopy (EM). Examination of EM images revealed that C0-C2 bound to F-actin to form long helically-ordered complexes. Fourier transforms indicated that C0-C2 binds with the helical periodicity of actin with strong 1st and 6th layer lines. The results provide direct evidence that the N-terminus of cMyBP-C can bind to F-actin in a periodic complex. This interaction of cMyBP-C with F-actin supports the possibility that binding of cMyBP-C to F-actin may play a role in the regulation of cardiac contraction.

  2. F-actin-rich contractile endothelial pores prevent vascular leakage during leukocyte diapedesis through local RhoA signalling.

    Science.gov (United States)

    Heemskerk, Niels; Schimmel, Lilian; Oort, Chantal; van Rijssel, Jos; Yin, Taofei; Ma, Bin; van Unen, Jakobus; Pitter, Bettina; Huveneers, Stephan; Goedhart, Joachim; Wu, Yi; Montanez, Eloi; Woodfin, Abigail; van Buul, Jaap D

    2016-01-27

    During immune surveillance and inflammation, leukocytes exit the vasculature through transient openings in the endothelium without causing plasma leakage. However, the exact mechanisms behind this intriguing phenomenon are still unknown. Here we report that maintenance of endothelial barrier integrity during leukocyte diapedesis requires local endothelial RhoA cycling. Endothelial RhoA depletion in vitro or Rho inhibition in vivo provokes neutrophil-induced vascular leakage that manifests during the physical movement of neutrophils through the endothelial layer. Local RhoA activation initiates the formation of contractile F-actin structures that surround emigrating neutrophils. These structures that surround neutrophil-induced endothelial pores prevent plasma leakage through actomyosin-based pore confinement. Mechanistically, we found that the initiation of RhoA activity involves ICAM-1 and the Rho GEFs Ect2 and LARG. In addition, regulation of actomyosin-based endothelial pore confinement involves ROCK2b, but not ROCK1. Thus, endothelial cells assemble RhoA-controlled contractile F-actin structures around endothelial pores that prevent vascular leakage during leukocyte extravasation.

  3. Cytotoxic effects of incense particles in relation to oxidative stress, the cell cycle and F-actin assembly.

    Science.gov (United States)

    Chuang, Hsiao-Chi; Jones, Tim; Chen, Tzu-Tao; BéruBé, Kelly

    2013-07-18

    Epidemiological studies have suggested that combustion-derived smoke, such as that produced during incense burning, is a deleterious air pollutant. It is capable of initiating oxidative stress and mutation; however, the related apoptotic processes remain unclear. In order to elucidate the biological mechanisms of reactive oxygen species (ROS)-induced respiratory toxicology, alveolar epithelial A549 cells were exposed to incense particulate matter (PM), with and without antioxidant N-acetyl-l-cysteine (NAC). The cross-linking associations between oxidative capacity, cell cycle events, actin cytoskeletal dynamics and intracellular calcium signals were investigated. An incense PM suspension caused significant oxidative stress in A549 cells, as shown by inhibition of the cell cycle at G1 and G2/M check-points, and the induction of apoptosis at Sub-G1. At the same time, alterations in the F-actin filamentous assemblies were observed. The levels of intracellular Ca(2+) were increased after incense PM exposure. Antioxidant NAC treatment revealed that oxidative stress and F-actin remodelling was significantly mitigated. This suggests that ROS accumulation could alter cell cycle regulation and anomalous remodelling of the cortical cytoskeleton that allowed impaired cells to enter into apoptosis. This study has elucidated the integral patho-physiological interactions of incense PM and the potential mechanisms for the development of ROS-driven respiratory impairment.

  4. Functional characterization of skeletal F-actin labeled on the NH2-terminal segment of residues 1-28.

    Science.gov (United States)

    Bertrand, R; Chaussepied, P; Audemard, E; Kassab, R

    1989-05-15

    Rabbit skeletal alpha-actin was covalently labeled in the filamentous state by the fluorescent nucleophile, N-(5-sulfo-1-naphthyl)ethylenediamine (EDANS) in the presence of the carboxyl group activator 1-(3-dimethyl-aminopropyl)-3-ethylcarbodiimide (EDC). The coupling reaction was continued until the incorporation of nearly 1 mol EDANS/mol actin. After limited proteolytic digestion of the labeled protein and chromatographic identification of the EDANS-peptides, about 80% of the attached fluorophore was found on the actin segment of residues 1-28, most probably within the N-terminal acidic region of residues 1-7. A minor labeling site was located on the segment that consists of residues 40-113. No label was incorporated into the COOH-terminal moiety consisting of residues 113-375. The isolated EDANS-G-actin undergoes polymerization in the presence of salts but at a rate significantly greater than unlabeled actin. The EDANS-F-actin could be complexed to skeletal chymotryptic myosin subfragment 1 (S-1) and to tropomyosin. The complex formed between EDANS-F-actin and S-1 could not be further crosslinked by EDC but the two proteins were readily joined by glutaraldehyde as observed for native actin-S-1, suggesting that the EDANS-substituted carboxyl site is also involved in the EDC crosslinking of native actin to S-1. Moreover, the EDANS labeling of F-actin resulted in a 20-fold increase in the Km of the actin-activated Mg2+.ATPase of S-1. Thus, this labeling, while it did not much affect the rigor actin-S-1 interaction, changes the actin binding to the S-1-nucleotide complexes significantly. The selective introduction of a variety of spectral probes, like EDANS, or other classes of fluorophores, on the N-terminal region of actin, through the reported carbodiimide coupling reaction, would provide several different derivatives valuable for assessing the functional role of the negatively charged N-terminus of actin during its interaction with myosin and other actin

  5. Cholesterol modulates the volume-regulated anion current in Ehrlich-Lettre ascites cells via effects on Rho and F-actin

    DEFF Research Database (Denmark)

    Klausen, Thomas Kjaer; Hougaard, Charlotte; Hoffmann, Else K

    2006-01-01

    )] in this process. In Ehrlich-Lettre ascites (ELA) cells, a current with biophysical and pharmacological properties characteristic of VRAC was activated by hypotonic swelling. A 44% increase in cellular cholesterol content had no detectable effects on F-actin organization or VRAC activity. A 47% reduction......) analogue or a PtdIns(4,5)P(2)-blocking antibody in the pipette, or neomycin treatment to sequester PtdIns(4,5)P(2). It is suggested that in ELA cells, F-actin and Rho-Rho kinase modulate VRAC magnitude and activation rate, respectively, and that cholesterol depletion potentiates VRAC at least in part...

  6. The effect of Cytochalasin D on F-Actin behavior of single-cell electroendocytosis using multi-chamber micro cell chip

    KAUST Repository

    Lin, Ran

    2012-03-01

    Electroendocytosis (EED) is a pulsed-electric-field (PEF) induced endocytosis, facilitating cells uptake molecules through nanometer-sized EED vesicles. We herein investigate the effect of a chemical inhibitor, Cytochalasin D (CD) on the actin-filaments (F-Actin) behavior of single-cell EED. The CD concentration (C CD) can control the depolymerization of F-actin. A multi-chamber micro cell chip was fabricated to study the EED under different conditions. Large-scale single-cell data demonstrated EED highly depends on both electric field and C CD. © 2012 IEEE.

  7. Cell swelling activates cloned Ca(2+)-activated K(+) channels: a role for the F-actin cytoskeleton

    DEFF Research Database (Denmark)

    Jorgensen, Nanna K; Pedersen, Stine F; Rasmussen, Hanne B;

    2003-01-01

    Cloned Ca(2+)-activated K(+) channels of intermediate (hIK) or small (rSK3) conductance were expressed in HEK 293 cells, and channel activity was monitored using whole-cell patch clamp. hIK and rSK3 currents already activated by intracellular calcium were further increased by 95% and 125......%, respectively, upon exposure of the cells to a 33% decrease in extracellular osmolarity. hIK and rSK3 currents were inhibited by 46% and 32%, respectively, by a 50% increase in extracellular osmolarity. Cell swelling and channel activation were not associated with detectable increases in [Ca(2+)](i), evidenced...... by population and single-cell measurements. In addition, inhibitors of IK and SK channels significantly reduced the rate of regulatory volume decrease (RVD) in cells expressing these channels. Cell swelling induced a decrease, and cell shrinkage an increase, in net cellular F-actin content. The swelling...

  8. Aggregatibacter actinomycetemcomitans Omp29 is associated with bacterial entry to gingival epithelial cells by F-actin rearrangement.

    Directory of Open Access Journals (Sweden)

    Mikihito Kajiya

    Full Text Available The onset and progressive pathogenesis of periodontal disease is thought to be initiated by the entry of Aggregatibacter actinomycetemcomitans (Aa into periodontal tissue, especially gingival epithelium. Nonetheless, the mechanism underlying such bacterial entry remains to be clarified. Therefore, this study aimed to investigate the possible role of Aa outer membrane protein 29 kD (Omp29, a homologue of E. coli OmpA, in promoting bacterial entry into gingival epithelial cells. To accomplish this, Omp29 expression vector was incorporated in an OmpA-deficient mutant of E. coli. Omp29(+/OmpA(- E. coli demonstrated 22-fold higher entry into human gingival epithelial line cells (OBA9 than Omp29(-/OmpA(- E. coli. While the entry of Aa and Omp29(+/OmpA(- E. coli into OBA9 cells were inhibited by anti-Omp29 antibody, their adherence to OBA9 cells was not inhibited. Stimulation of OBA9 cells with purified Omp29 increased the phosphorylation of focal adhesion kinase (FAK, a pivotal cell-signaling molecule that can up-regulate actin rearrangement. Furthermore, Omp29 increased the formation of F-actin in OBA9 cells. The internalization of Omp29-coated beads and the entry of Aa into OBA9 were partially inhibited by treatment with PI3-kinase inhibitor (Wortmannin and Rho GTPases inhibitor (EDIN, both known to convey FAK-signaling to actin-rearrangement. These results suggest that Omp29 is associated with the entry of Aa into gingival epithelial cells by up-regulating F-actin rearrangement via the FAK signaling pathway.

  9. Mitochondrial Dysfunction, Disruption of F-Actin Polymerization, and Transcriptomic Alterations in Zebrafish Larvae Exposed to Trichloroethylene.

    Science.gov (United States)

    Wirbisky, Sara E; Damayanti, Nur P; Mahapatra, Cecon T; Sepúlveda, Maria S; Irudayaraj, Joseph; Freeman, Jennifer L

    2016-02-15

    Trichloroethylene (TCE) is primarily used as an industrial degreasing agent and has been in use since the 1940s. TCE is released into the soil, surface, and groundwater. From an environmental and regulatory standpoint, more than half of Superfund hazardous waste sites on the National Priority List are contaminated with TCE. Occupational exposure to TCE occurs primarily via inhalation, while environmental TCE exposure also occurs through ingestion of contaminated drinking water. Current literature links TCE exposure to various adverse health effects including cardiovascular toxicity. Current studies aiming to address developmental cardiovascular toxicity utilized rodent and avian models, with the majority of studies using relatively higher parts per million (mg/L) doses. In this study, to further investigate developmental cardiotoxicity of TCE, zebrafish embryos were treated with 0, 10, 100, or 500 parts per billion (ppb; μg/L) TCE during embryogenesis and/or through early larval stages. After the appropriate exposure period, angiogenesis, F-actin, and mitochondrial function were assessed. A significant dose-response decrease in angiogenesis, F-actin, and mitochondrial function was observed. To further complement this data, a transcriptomic profile of zebrafish larvae was completed to identify gene alterations associated with the 10 ppb TCE exposure. Results from the transcriptomic data revealed that embryonic TCE exposure caused significant changes in genes associated with cardiovascular disease, cancer, and organismal injury and abnormalities with a number of targets in the FAK signaling pathway. Overall, results from our study support TCE as a developmental cardiovascular toxicant, provide molecular targets and pathways for investigation in future studies, and indicate a need for continued priority for environmental regulation.

  10. Hyperosmotic stress induces Rho/Rho kinase/LIM kinase-mediated cofilin phosphorylation in tubular cells: key role in the osmotically triggered F-actin response

    DEFF Research Database (Denmark)

    Thirone, Ana C P; Speight, Pam; Zulys, Matthew;

    2009-01-01

    we investigated whether hyperosmolarity regulates cofilin, a key actin-severing protein, whose activity is inhibited by phosphorylation. Since the small GTPases Rho and Rac are sensitive to cell volume changes, and can regulate cofilin phosphorylation, we also asked if they might link osmostress...... in the hyperosmotic stress-induced F-actin increase. Key words: cytoskeleton, hypertonicity, cell volume, small GTPases....

  11. Moesin is required for HIV-1-induced CD4-CXCR4 interaction, F-actin redistribution, membrane fusion and viral infection in lymphocytes.

    Science.gov (United States)

    Barrero-Villar, Marta; Cabrero, José Román; Gordón-Alonso, Mónica; Barroso-González, Jonathan; Alvarez-Losada, Susana; Muñoz-Fernández, M Angeles; Sánchez-Madrid, Francisco; Valenzuela-Fernández, Agustín

    2009-01-01

    The human immunodeficiency virus 1 (HIV-1) envelope regulates the initial attachment of viral particles to target cells through its association with CD4 and either CXCR4 or CCR5. Although F-actin is required for CD4 and CXCR4 redistribution, little is known about the molecular mechanisms underlying this fundamental process in HIV infection. Using CD4(+) CXCR4(+) permissive human leukemic CEM T cells and primary lymphocytes, we have investigated whether HIV-1 Env might promote viral entry and infection by activating ERM (ezrin-radixin-moesin) proteins to regulate F-actin reorganization and CD4/CXCR4 co-clustering. The interaction of the X4-tropic protein HIV-1 gp120 with CD4 augments ezrin and moesin phosphorylation in human permissive T cells, thereby regulating ezrin-moesin activation. Moreover, the association and clustering of CD4-CXCR4 induced by HIV-1 gp120 requires moesin-mediated anchoring of actin in the plasma membrane. Suppression of moesin expression with dominant-negative N-moesin or specific moesin silencing impedes reorganization of F-actin and HIV-1 entry and infection mediated by the HIV-1 envelope protein complex. Therefore, we propose that activated moesin promotes F-actin redistribution and CD4-CXCR4 clustering and is also required for efficient X4-tropic HIV-1 infection in permissive lymphocytes.

  12. The NAV2 homolog Sickie regulates F-actin-mediated axonal growth in Drosophila mushroom body neurons via the non-canonical Rac-Cofilin pathway.

    Science.gov (United States)

    Abe, Takashi; Yamazaki, Daisuke; Murakami, Satoshi; Hiroi, Makoto; Nitta, Yohei; Maeyama, Yuko; Tabata, Tetsuya

    2014-12-01

    The Rac-Cofilin pathway is essential for cytoskeletal remodeling to control axonal development. Rac signals through the canonical Rac-Pak-LIMK pathway to suppress Cofilin-dependent axonal growth and through a Pak-independent non-canonical pathway to promote outgrowth. Whether this non-canonical pathway converges to promote Cofilin-dependent F-actin reorganization in axonal growth remains elusive. We demonstrate that Sickie, a homolog of the human microtubule-associated protein neuron navigator 2, cell-autonomously regulates axonal growth of Drosophila mushroom body (MB) neurons via the non-canonical pathway. Sickie was prominently expressed in the newborn F-actin-rich axons of MB neurons. A sickie mutant exhibited axonal growth defects, and its phenotypes were rescued by exogenous expression of Sickie. We observed phenotypic similarities and genetic interactions among sickie and Rac-Cofilin signaling components. Using the MARCM technique, distinct F-actin and phospho-Cofilin patterns were detected in developing axons mutant for sickie and Rac-Cofilin signaling regulators. The upregulation of Cofilin function alleviated the axonal defect of the sickie mutant. Epistasis analyses revealed that Sickie suppresses the LIMK overexpression phenotype and is required for Pak-independent Rac1 and Slingshot phosphatase to counteract LIMK. We propose that Sickie regulates F-actin-mediated axonal growth via the non-canonical Rac-Cofilin pathway in a Slingshot-dependent manner.

  13. Bulkiness or aromatic nature of tyrosine-143 of actin is important for the weak binding between F-actin and myosin-ADP-phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Gomibuchi, Yuki [Graduate School of Science and Engineering, Teikyo University, Toyosatodai 1-1, Utsunomiya 320-8551 (Japan); Uyeda, Taro Q.P. [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Wakabayashi, Takeyuki, E-mail: tw007@nasu.bio.teikyo-u.ac.jp [Graduate School of Science and Engineering, Teikyo University, Toyosatodai 1-1, Utsunomiya 320-8551 (Japan); Department of Judo Therapy, Faculty of Medical Technology, Teikyo University, Toyosatodai 1-1, Utsunomiya 320-8551 (Japan)

    2013-11-29

    Highlights: •The effect of mutation of Tyr143 that becomes more exposed on assembly was examined. •Mutation of tyrosine-143 of Dictyostelium actin changed actin polymerizability. •The bulkiness or aromatic nature of Tyr143 is important for the weak binding. •The weak interaction between myosin and actin strengthened by Tyr143Trp mutation. -- Abstract: Actin filaments (F-actin) interact with myosin and activate its ATPase to support force generation. By comparing crystal structures of G-actin and the quasi-atomic model of F-actin based on high-resolution cryo-electron microscopy, the tyrosine-143 was found to be exposed more than 60 Å{sup 2} to the solvent in F-actin. Because tyrosine-143 flanks the hydrophobic cleft near the hydrophobic helix that binds to myosin, the mutant actins, of which the tyrosine-143 was replaced with tryptophan, phenylalanine, or isoleucine, were generated using the Dictyostelium expression system. It polymerized significantly poorly when induced by NaCl, but almost normally by KCl. In the presence of phalloidin and KCl, the extents of the polymerization of all the mutant actins were comparable to that of the wild-type actin so that the actin-activated myosin ATPase activity could be reliably compared. The affinity of skeletal heavy meromyosin to F-actin and the maximum ATPase activity (V{sub max}) were estimated by a double reciprocal plot. The Tyr143Trp-actin showed the higher affinity (smaller K{sub app}) than that of the wild-type actin, with the V{sub max} being almost unchanged. The K{sub app} and V{sub max} of the Tyr143Phe-actin were similar to those of the wild-type actin. However, the activation by Tyr143Ile-actin was much smaller than the wild-type actin and the accurate determination of K{sub app} was difficult. Comparison of the myosin ATPase activated by the various mutant actins at the same concentration of F-actin showed that the extent of activation correlates well with the solvent-accessible surface areas (ASA

  14. Cholesterol modulates the volume-regulated anion current in Ehrlich-Lettre ascites cells via effects on Rho and F-actin.

    Science.gov (United States)

    Klausen, Thomas Kjaer; Hougaard, Charlotte; Hoffmann, Else K; Pedersen, Stine F

    2006-10-01

    The mechanisms controlling the volume-regulated anion current (VRAC) are incompletely elucidated. Here, we investigate the modulation of VRAC by cellular cholesterol and the potential involvement of F-actin, Rho, Rho kinase, and phosphatidylinositol-(4,5)-bisphosphate [PtdIns(4,5)P(2)] in this process. In Ehrlich-Lettre ascites (ELA) cells, a current with biophysical and pharmacological properties characteristic of VRAC was activated by hypotonic swelling. A 44% increase in cellular cholesterol content had no detectable effects on F-actin organization or VRAC activity. A 47% reduction in cellular cholesterol content increased cortical and stress fiber-associated F-actin content in swollen cells. Cholesterol depletion increased VRAC activation rate and maximal current after a modest (15%), but not after a severe (36%) reduction in extracellular osmolarity. The cholesterol depletion-induced increase in maximal VRAC current was prevented by F-actin disruption using latrunculin B (LB), while the current activation rate was unaffected by LB, but dependent on Rho kinase. Rho activity was decreased by approximately 20% in modestly, and approximately 50% in severely swollen cells. In modestly swollen cells, this reduction was prevented by cholesterol depletion, which also increased isotonic Rho activity. Thrombin, which stimulates Rho and causes actin polymerization, potentiated VRAC in modestly swollen cells. VRAC activity was unaffected by inclusion of a water-soluble PtdIns(4,5)P(2) analogue or a PtdIns(4,5)P(2)-blocking antibody in the pipette, or neomycin treatment to sequester PtdIns(4,5)P(2). It is suggested that in ELA cells, F-actin and Rho-Rho kinase modulate VRAC magnitude and activation rate, respectively, and that cholesterol depletion potentiates VRAC at least in part by preventing the hypotonicity-induced decrease in Rho activity and eliciting actin polymerization.

  15. Decavanadate binding to a high affinity site near the myosin catalytic centre inhibits F-actin-stimulated myosin ATPase activity.

    Science.gov (United States)

    Tiago, Teresa; Aureliano, Manuel; Gutiérrez-Merino, Carlos

    2004-05-11

    Decameric vanadate (V(10)) inhibits the actin-stimulated myosin ATPase activity, noncompetitively with actin or with ATP upon interaction with a high-affinity binding site (K(i) = 0.27 +/- 0.05 microM) in myosin subfragment-1 (S1). The binding of V(10) to S1 can be monitored from titration with V(10) of the fluorescence of S1 labeled at Cys-707 and Cys-697 with N-iodo-acetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine (IAEDANS) or 5-(iodoacetamido) fluorescein, which showed the presence of only one V(10) binding site per monomer with a dissociation constant of 0.16-0.7 microM, indicating that S1 labeling with these dyes produced only a small distortion of the V(10) binding site. The large quenching of AEDANS-labeled S1 fluorescence produced by V(10) indicated that the V(10) binding site is close to Cys-697 and 707. Fluorescence studies demonstrated the following: (i) the binding of V(10) to S1 is not competitive either with actin or with ADP.V(1) or ADP.AlF(4); (ii) the affinity of V(10) for the complex S1/ADP.V(1) and S1/ADP.AlF(4) is 2- and 3-fold lower than for S1; and (iii) it is competitive with the S1 "back door" ligand P(1)P(5)-diadenosine pentaphosphate. A local conformational change in S1 upon binding of V(10) is supported by (i) a decrease of the efficiency of fluorescence energy transfer between eosin-labeled F-actin and fluorescein-labeled S1, and (ii) slower reassociation between S1 and F-actin after ATP hydrolysis. The results are consistent with binding of V(10) to the Walker A motif of ABC ATPases, which in S1 corresponds to conserved regions of the P-loop which form part of the phosphate tube.

  16. Septins promote F-actin ring formation by crosslinking actin filaments into curved bundles.

    Science.gov (United States)

    Mavrakis, Manos; Azou-Gros, Yannick; Tsai, Feng-Ching; Alvarado, José; Bertin, Aurélie; Iv, Francois; Kress, Alla; Brasselet, Sophie; Koenderink, Gijsje H; Lecuit, Thomas

    2014-04-01

    Animal cell cytokinesis requires a contractile ring of crosslinked actin filaments and myosin motors. How contractile rings form and are stabilized in dividing cells remains unclear. We address this problem by focusing on septins, highly conserved proteins in eukaryotes whose precise contribution to cytokinesis remains elusive. We use the cleavage of the Drosophila melanogaster embryo as a model system, where contractile actin rings drive constriction of invaginating membranes to produce an epithelium in a manner akin to cell division. In vivo functional studies show that septins are required for generating curved and tightly packed actin filament networks. In vitro reconstitution assays show that septins alone bundle actin filaments into rings, accounting for the defects in actin ring formation in septin mutants. The bundling and bending activities are conserved for human septins, and highlight unique functions of septins in the organization of contractile actomyosin rings.

  17. Ablation of EYS in zebrafish causes mislocalisation of outer segment proteins, F-actin disruption and cone-rod dystrophy

    Science.gov (United States)

    Lu, Zhaojing; Hu, Xuebin; Liu, Fei; Soares, Dinesh C.; Liu, Xiliang; Yu, Shanshan; Gao, Meng; Han, Shanshan; Qin, Yayun; Li, Chang; Jiang, Tao; Luo, Daji; Guo, An-Yuan; Tang, Zhaohui; Liu, Mugen

    2017-01-01

    Mutations in EYS are associated with autosomal recessive retinitis pigmentosa (arRP) and autosomal recessive cone-rod dystrophy (arCRD) however, the function of EYS and the molecular mechanisms of how these mutations cause retinal degeneration are still unclear. Because EYS is absent in mouse and rat, and the structure of the retina differs substantially between humans and Drosophila, we utilised zebrafish as a model organism to study the function of EYS in the retina. We constructed an EYS-knockout zebrafish-line by TALEN technology which showed visual impairment at an early age, while the histological and immunofluorescence assays indicated the presence of progressive retinal degeneration with a cone predominately affected pattern. These phenotypes recapitulate the clinical manifestations of arCRD patients. Furthermore, the EYS−/− zebrafish also showed mislocalisation of certain outer segment proteins (rhodopsin, opn1lw, opn1sw1, GNB3 and PRPH2), and disruption of actin filaments in photoreceptors. Protein mislocalisation may, therefore, disrupt the function of cones and rods in these zebrafish and cause photoreceptor death. Collectively, these results point to a novel role for EYS in maintaining the morphological structure of F-actin and in protein transport, loss of this function might be the trigger for the resultant cellular events that ultimately lead to photoreceptor death. PMID:28378834

  18. Regulation of SGLT expression and localization through Epac/PKA-dependent caveolin-1 and F-actin activation in renal proximal tubule cells.

    Science.gov (United States)

    Lee, Yu Jin; Kim, Mi Ok; Ryu, Jung Min; Han, Ho Jae

    2012-04-01

    This study demonstrated that exchange proteins directly activated by cAMP (Epac) and protein kinase A (PKA) by 8-bromo (8-Br)-adenosine 3',5'-cyclic monophosphate (cAMP) stimulated [(14)C]-α-methyl-D-glucopyranoside (α-MG) uptake through increased sodium-glucose cotransporters (SGLTs) expression and translocation to lipid rafts in renal proximal tubule cells (PTCs). In PTCs, SGLTs were colocalized with lipid raft caveolin-1 (cav-1), disrupted by methyl-β-cyclodextrin (MβCD). Selective activators of Epac or PKA, 8-Br-cAMP, and forskolin stimulated expressions of SGLTs and α-MG uptake in PTCs. In addition, 8-Br-cAMP-induced PKA and Epac activation increased phosphorylation of extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), and nuclear factor kappa B (NF-κB), which were involved in expressions of SGLTs. Furthermore, 8-Br-cAMP stimulated SGLTs translocation to lipid rafts via filamentous actin (F-actin) organization, which was blocked by cytochalasin D. In addition, cav-1 and SGLTs stimulated by 8-Br-cAMP were detected in lipid rafts, which were blocked by cytochalasin D. Furthermore, 8-Br-cAMP-induced SGLTs translocation and α-MG uptake were attenuated by inhibition of cav-1 activation with cav-1 small interfering RNA (siRNA) and inhibition of F-actin organization with TRIO and F-actin binding protein (TRIOBP). In conclusion, 8-Br-cAMP stimulated α-MG uptake via Epac and PKA-dependent SGLTs expression and trafficking through cav-1 and F-actin in PTCs.

  19. Parvin overexpression uncovers tissue-specific genetic pathways and disrupts F-actin to induce apoptosis in the developing epithelia in Drosophila.

    Directory of Open Access Journals (Sweden)

    Maria Chountala

    Full Text Available Parvin is a putative F-actin binding protein important for integrin-mediated cell adhesion. Here we used overexpression of Drosophila Parvin to uncover its functions in different tissues in vivo. Parvin overexpression caused major defects reminiscent of metastatic cancer cells in developing epithelia, including apoptosis, alterations in cell shape, basal extrusion and invasion. These defects were closely correlated with abnormalities in the organization of F-actin at the basal epithelial surface and of integrin-matrix adhesion sites. In wing epithelium, overexpressed Parvin triggered increased Rho1 protein levels, predominantly at the basal side, whereas in the developing eye it caused a rough eye phenotype and severely disrupted F-actin filaments at the retina floor of pigment cells. We identified genes that suppressed these Parvin-induced dominant effects, depending on the cell type. Co-expression of both ILK and the apoptosis inhibitor DIAP1 blocked Parvin-induced lethality and apoptosis and partially ameliorated cell delamination in epithelia, but did not rescue the elevated Rho1 levels, the abnormal organization of F-actin in the wing and the assembly of integrin-matrix adhesion sites. The rough eye phenotype was suppressed by coexpression of either PTEN or Wech, or by knock-down of Xrp1. Two main conclusions can be drawn from our studies: (1, high levels of cytoplasmic Parvin are toxic in epithelial cells; (2 Parvin in a dose dependent manner affects the organization of actin cytoskeleton in both wing and eye epithelia, independently of its role as a structural component of the ILK-PINCH-Parvin complex that mediates the integrin-actin link. Thus, distinct genetic interactions of Parvin occur in different cell types and second site modifier screens are required to uncover such genetic circuits.

  20. Platelet rich plasma promotes skeletal muscle cell migration in association with up-regulation of FAK, paxillin, and F-Actin formation.

    Science.gov (United States)

    Tsai, Wen-Chung; Yu, Tung-Yang; Lin, Li-Ping; Lin, Mioa-Sui; Tsai, Ting-Ta; Pang, Jong-Hwei S

    2017-02-24

    Platelet rich plasma (PRP) contains various cytokines and growth factors which may be beneficial to the healing process of injured muscle. The aim of this study was to investigate the effect and molecular mechanism of PRP on migration of skeletal muscle cells. Skeletal muscle cells intrinsic to Sprague-Dawley rats were treated with PRP. The cell migration was evaluated by transwell filter migration assay and electric cell-substrate impedance sensing. The spreading of cells was evaluated microscopically. The formation of filamentous actin (F-actin) cytoskeleton was assessed by immunofluorescence staining. The protein expressions of paxillin and focal adhesion kinase (FAK) were assessed by Western blot analysis. Transfection of paxillin small-interfering RNA (siRNAs) to muscle cells was performed to validate the role of paxillin in PRP-mediated promotion of cell migration. Dose-dependently PRP promotes migration of and spreading and muscle cells. Protein expressions of paxillin and FAK were up-regulated dose-dependently. F-actin formation was also enhanced by PRP treatment. Furthermore, the knockdown of paxillin expression impaired the effect of PRP to promote cell migration. It was concluded that PRP promoting migration of muscle cells is associated with up-regulation of proteins expression of paxillin and FAK as well as increasing F-actin formation. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

  1. Excess F-actin mechanically impedes mitosis leading to cytokinesis failure in X-linked neutropenia by exceeding Aurora B kinase error correction capacity.

    Science.gov (United States)

    Moulding, Dale A; Moeendarbary, Emad; Valon, Leo; Record, Julien; Charras, Guillaume T; Thrasher, Adrian J

    2012-11-01

    The constitutively active mutant of the Wiskott-Aldrich Syndrome protein (CA-WASp) is the cause of X-linked neutropenia and is linked with genomic instability and myelodysplasia. CA-WASp generates abnormally high levels of cytoplasmic F-actin through dysregulated activation of the Arp2/3 complex leading to defects in cell division. As WASp has no reported role in cell division, we hypothesized that alteration of cell mechanics because of increased F-actin may indirectly disrupt dynamic events during mitosis. Inhibition of the Arp2/3 complex revealed that excess cytoplasmic F-actin caused increased cellular viscosity, slowed all phases of mitosis, and perturbed mitotic mechanics. Comparison of chromosome velocity to the cytoplasmic viscosity revealed that cells compensated for increased viscosity by up-regulating force applied to chromosomes and increased the density of microtubules at kinetochores. Mitotic abnormalities were because of overload of the aurora signaling pathway as subcritical inhibition of Aurora in CA-WASp cells caused increased cytokinesis failure, while overexpression reduced defects. These findings demonstrate that changes in cell mechanics can cause significant mitotic abnormalities leading to genomic instability, and highlight the importance of mechanical sensors such as Aurora B in maintaining the fidelity of hematopoietic cell division.

  2. Re-evaluating the roles of myosin 18Aα and F-actin in determining Golgi morphology.

    Science.gov (United States)

    Bruun, Kyle; Beach, Jordan R; Heissler, Sarah M; Remmert, Kirsten; Sellers, James R; Hammer, John A

    2017-03-22

    The peri-centrosomal localization and morphology of the Golgi apparatus depends largely on the microtubule cytoskeleton and the microtubule motor protein dynein. Recent studies proposed that myosin 18Aα (M18Aα) also contributes to Golgi morphology by binding the Golgi protein GOLPH3 and walking along adjacent actin filaments to stretch the Golgi into its classic ribbon structure. Biochemical analyses have shown, however, that M18A is not an actin-activated ATPase and lacks motor activity. Our goal, therefore, was to define the precise molecular mechanism by which M18Aα determines Golgi morphology. We show that purified M18Aα remains inactive in the presence of GOLPH3, arguing against the Golgi-specific activation of the myosin. Using M18A-specific antibodies and expression of GFP-tagged M18Aα, we find no evidence that it localizes to the Golgi. Moreover, several cell lines with reduced or eliminated M18Aα expression exhibited normal Golgi morphology. Interestingly, actin filament disassembly resulted in a marked reduction in lateral stretching of the Golgi in both control and M18Aα-deficient cells. Importantly, this reduction was accompanied by an expansion of the Golgi in the vertical direction, vertical movement of the centrosome, and increases in the height of both the nucleus and the cell. Collectively, our data indicate that M18Aα does not localize to the Golgi or play a significant role in determining its morphology, and suggest that global F-actin disassembly alters Golgi morphology indirectly by altering cell shape. This article is protected by copyright. All rights reserved.

  3. Competition for actin between two distinct F-actin networks defines a bistable switch for cell polarization.

    Science.gov (United States)

    Lomakin, Alexis J; Lee, Kun-Chun; Han, Sangyoon J; Bui, Duyen A; Davidson, Michael; Mogilner, Alex; Danuser, Gaudenz

    2015-11-01

    Symmetry-breaking polarization enables functional plasticity of cells and tissues and is yet not well understood. Here we show that epithelial cells, hard-wired to maintain a static morphology and to preserve tissue organization, can spontaneously switch to a migratory polarized phenotype after relaxation of the actomyosin cytoskeleton. We find that myosin II engages actin in the formation of cortical actomyosin bundles and thus makes it unavailable for deployment in the process of dendritic growth normally driving cell motility. Under low-contractility regimes, epithelial cells polarize in a front-back manner owing to the emergence of actin retrograde flows powered by dendritic polymerization of actin. Coupled to cell movement, the flows transport myosin II from the front to the back of the cell, where the motor locally 'locks' actin in contractile bundles. This polarization mechanism could be employed by embryonic and cancer epithelial cells in microenvironments where high-contractility-driven cell motion is inefficient.

  4. The structural dynamics of α-tropomyosin on F-actin shape the overlap complex between adjacent tropomyosin molecules

    Science.gov (United States)

    Lehman, William; Li, Xiaochuan (Edward); Orzechowski, Marek; Fischer, Stefan

    2013-01-01

    Coiled-coil tropomyosin, localized on actin filaments in virtually all eukaryotic cells, serves as a gatekeeper regulating access of the motor protein myosin and other actin-binding proteins onto the thin filament surface. Tropomyosin's modular pseudo-repeating pattern of approximately 39 amino acid residues is designed to allow binding of the coiled-coil to successive actin subunits along thin filaments. Even though different tropomyosin isoforms contain varying numbers of repeat modules, the pseudo-repeat length, in all cases, matches that of a single actin subunit. Thus, the seven pseudo-repeats of 42 nm long muscle tropomyosin bind to seven successive actin subunits along thin filaments, while simultaneously bending into a super-helical conformation that is preshaped to the actin filament helix. In order to form a continuous cable on thin filaments that is free of gaps, adjacent tropomyosin molecules polymerize head-to-tail by means of a short (∼9 residue) overlap. Several laboratories have engineered peptides to mimic the N- and C-terminal tropomyosin association and to characterize the overlap structure. All overlapping domains examined show a compact N-terminal coiled-coil inserting into a partially opened C-terminal partner, where the opposing coiled-coils at the overlap junction face each other at up to ∼90° twist angles. Here, Molecular Dynamics (MD) simulations were carried out to determine constraints on the formation of the tropomyosin overlap complex and to assess the amount of twisting exhibited by full-length tropomyosin when bound to actin. With the exception of the last 20 to 40 C- and N-terminal residues, we find that the average tropomyosin structure closely resembles a “canonical” model proposed in the classic work of McLachlan and Stewart, displaying perfectly symmetrical supercoil geometry matching the F-actin helix with an integral number of coiled-coil turns, a coiled-coil helical pitch of 137 Å, a superhelical pitch of 770

  5. Noise-induced cochlear F-actin depolymerization is mediated via ROCK2/p-ERM signaling.

    Science.gov (United States)

    Han, Yu; Wang, Xianren; Chen, Jun; Sha, Su-Hua

    2015-06-01

    Our previous work has suggested that traumatic noise activates Rho-GTPase pathways in cochlear outer hair cells (OHCs), resulting in cell death and noise-induced hearing loss (NIHL). In this study, we investigated Rho effectors, Rho-associated kinases (ROCKs), and the targets of ROCKs, the ezrin-radixin-moesin (ERM) proteins, in the regulation of the cochlear actin cytoskeleton using adult CBA/J mice under conditions of noise-induced temporary threshold shift (TTS) and permanent threshold shift (PTS) hearing loss, which result in changes to the F/G-actin ratio. The levels of cochlear ROCK2 and p-ERM decreased 1 h after either TTS- or PTS-noise exposure. In contrast, ROCK2 and p-ERM in OHCs decreased only after PTS-, not after TTS-noise exposure. Treatment with lysophosphatidic acid, an activator of the Rho pathway, resulted in significant reversal of the F/G-actin ratio changes caused by noise exposure and attenuated OHC death and NIHL. Conversely, the down-regulation of ROCK2 by pretreatment with ROCK2 siRNA reduced the expression of ROCK2 and p-ERM in OHCs, exacerbated TTS to PTS, and worsened OHC loss. Additionally, pretreatment with siRNA against radixin, an ERM protein, aggravated TTS to PTS. Our results indicate that a ROCK2-mediated ERM-phosphorylation signaling cascade modulates noise-induced hair cell loss and NIHL by targeting the cytoskeleton. We propose the following cascade following noise trauma leading to alteration of the F-actin arrangement in the outer hair cell cytoskeleton: Noise exposure reduces the levels of GTP-RhoA and subsequently diminishes levels of RhoA effector ROCK2 (Rho-associated kinase 2). Phosphorylation of ezrin-radixin-moesin (ERM) by ROCK2 normally allows ERM to cross-link actin filaments with the plasma membrane. Noise-decreased levels of ROCK results in reduction of phosphorylation of ERM that leads to depolymerization of actin filaments. Lysophosphatidic acid (LPA), an agonist of RhoA, binds to the G-protein-coupled receptor

  6. Apical domain polarization localizes actin-myosin activity to drive ratchet-like apical constriction.

    Science.gov (United States)

    Mason, Frank M; Tworoger, Michael; Martin, Adam C

    2013-08-01

    Apical constriction promotes epithelia folding, which changes tissue architecture. During Drosophila gastrulation, mesoderm cells exhibit repeated contractile pulses that are stabilized such that cells apically constrict like a ratchet. The transcription factor Twist is required to stabilize cell shape. However, it is unknown how Twist spatially coordinates downstream signals to prevent cell relaxation. We find that during constriction, Rho-associated kinase (Rok) is polarized to the middle of the apical domain (medioapical cortex), separate from adherens junctions. Rok recruits or stabilizes medioapical myosin II (Myo-II), which contracts dynamic medioapical actin cables. The formin Diaphanous mediates apical actin assembly to suppress medioapical E-cadherin localization and form stable connections between the medioapical contractile network and adherens junctions. Twist is not required for apical Rok recruitment, but instead polarizes Rok medioapically. Therefore, Twist establishes radial cell polarity of Rok/Myo-II and E-cadherin and promotes medioapical actin assembly in mesoderm cells to stabilize cell shape fluctuations.

  7. Cochlear outer hair cells undergo an apical circumference remodeling constrained by the hair bundle shape.

    Science.gov (United States)

    Etournay, Raphaël; Lepelletier, Léa; Boutet de Monvel, Jacques; Michel, Vincent; Cayet, Nadège; Leibovici, Michel; Weil, Dominique; Foucher, Isabelle; Hardelin, Jean-Pierre; Petit, Christine

    2010-04-01

    Epithelial cells acquire diverse shapes relating to their different functions. This is particularly relevant for the cochlear outer hair cells (OHCs), whose apical and basolateral shapes accommodate the functioning of these cells as mechano-electrical and electromechanical transducers, respectively. We uncovered a circumferential shape transition of the apical junctional complex (AJC) of OHCs, which occurs during the early postnatal period in the mouse, prior to hearing onset. Geometric analysis of the OHC apical circumference using immunostaining of the AJC protein ZO1 and Fourier-interpolated contour detection characterizes this transition as a switch from a rounded-hexagon to a non-convex circumference delineating two lateral lobes at the neural side of the cell, with a negative curvature in between. This shape tightly correlates with the 'V'-configuration of the OHC hair bundle, the apical mechanosensitive organelle that converts sound-evoked vibrations into variations in cell membrane potential. The OHC apical circumference remodeling failed or was incomplete in all the mouse mutants affected in hair bundle morphogenesis that we tested. During the normal shape transition, myosin VIIa and myosin II (A and B isoforms) displayed polarized redistributions into and out of the developing lobes, respectively, while Shroom2 and F-actin transiently accumulated in the lobes. Defects in these redistributions were observed in the mutants, paralleling their apical circumference abnormalities. Our results point to a pivotal role for actomyosin cytoskeleton tensions in the reshaping of the OHC apical circumference. We propose that this remodeling contributes to optimize the mechanical coupling between the basal and apical poles of mature OHCs.

  8. Myosin II ATPase activity mediates the long-term potentiation-induced exodus of stable F-actin bound by drebrin A from dendritic spines.

    Directory of Open Access Journals (Sweden)

    Toshiyuki Mizui

    Full Text Available The neuronal actin-binding protein drebrin A forms a stable structure with F-actin in dendritic spines. NMDA receptor activation causes an exodus of F-actin bound by drebrin A (DA-actin from dendritic spines, suggesting a pivotal role for DA-actin exodus in synaptic plasticity. We quantitatively assessed the extent of DA-actin localization to spines using the spine-dendrite ratio of drebrin A in cultured hippocampal neurons, and found that (1 chemical long-term potentiation (LTP stimulation induces rapid DA-actin exodus and subsequent DA-actin re-entry in dendritic spines, (2 Ca(2+ influx through NMDA receptors regulates the exodus and the basal accumulation of DA-actin, and (3 the DA-actin exodus is blocked by myosin II ATPase inhibitor, but is not blocked by myosin light chain kinase (MLCK or Rho-associated kinase (ROCK inhibitors. These results indicate that myosin II mediates the interaction between NMDA receptor activation and DA-actin exodus in LTP induction. Furthermore, myosin II seems to be activated by a rapid actin-linked mechanism rather than slow MLC phosphorylation. Thus the myosin-II mediated DA-actin exodus might be an initial event in LTP induction, triggering actin polymerization and spine enlargement.

  9. Myosin II ATPase activity mediates the long-term potentiation-induced exodus of stable F-actin bound by drebrin A from dendritic spines.

    Science.gov (United States)

    Mizui, Toshiyuki; Sekino, Yuko; Yamazaki, Hiroyuki; Ishizuka, Yuta; Takahashi, Hideto; Kojima, Nobuhiko; Kojima, Masami; Shirao, Tomoaki

    2014-01-01

    The neuronal actin-binding protein drebrin A forms a stable structure with F-actin in dendritic spines. NMDA receptor activation causes an exodus of F-actin bound by drebrin A (DA-actin) from dendritic spines, suggesting a pivotal role for DA-actin exodus in synaptic plasticity. We quantitatively assessed the extent of DA-actin localization to spines using the spine-dendrite ratio of drebrin A in cultured hippocampal neurons, and found that (1) chemical long-term potentiation (LTP) stimulation induces rapid DA-actin exodus and subsequent DA-actin re-entry in dendritic spines, (2) Ca(2+) influx through NMDA receptors regulates the exodus and the basal accumulation of DA-actin, and (3) the DA-actin exodus is blocked by myosin II ATPase inhibitor, but is not blocked by myosin light chain kinase (MLCK) or Rho-associated kinase (ROCK) inhibitors. These results indicate that myosin II mediates the interaction between NMDA receptor activation and DA-actin exodus in LTP induction. Furthermore, myosin II seems to be activated by a rapid actin-linked mechanism rather than slow MLC phosphorylation. Thus the myosin-II mediated DA-actin exodus might be an initial event in LTP induction, triggering actin polymerization and spine enlargement.

  10. Difference in F-Actin Depolymerization Induced by Toxin B from the Clostridium difficile Strain VPI 10463 and Toxin B from the Variant Clostridium difficile Serotype F Strain 1470

    Directory of Open Access Journals (Sweden)

    Harald Genth

    2013-01-01

    Full Text Available Clostridium difficile toxin A (TcdA and toxin B (TcdB are the causative agent of the C. difficile-associated diarrhea (CDAD and its severe form, the pseudomembranous colitis (PMC. TcdB from the C. difficile strain VPI10463 mono-glucosylates (thereby inactivates the small GTPases Rho, Rac, and Cdc42, while Toxin B from the variant C. difficile strain serotype F 1470 (TcdBF specifically mono-glucosylates Rac but not Rho(A/B/C. TcdBF is related to lethal toxin from C. sordellii (TcsL that glucosylates Rac1 but not Rho(A/B/C. In this study, the effects of Rho-inactivating toxins on the concentrations of cellular F-actin were investigated using the rhodamine-phalloidin-based F-actin ELISA. TcdB induces F-actin depolymerization comparable to the RhoA-inactivating exoenzyme C3 from C. limosum (C3-lim. In contrast, the Rac-glucosylating toxins TcdBF and TcsL did not cause F-actin depolymerization. These observations led to the conclusion that F-actin depolymerization depends on the toxin’s capability of glucosylating RhoA. Furthermore, the integrity of focal adhesions (FAs was analyzed using paxillin and p21-activated kinase (PAK as FA marker proteins. Paxillin dephosphorylation was observed upon treatment of cells with TcdB, TcdBF, or C3-lim. In conclusion, the Rho-inactivating toxins induce loss of cell shape by either F-actin depolymerization (upon RhoA inactivation or the disassembly of FAs (upon Rac1 inactivation.

  11. Left ventricular apical diseases.

    Science.gov (United States)

    Cisneros, Silvia; Duarte, Ricardo; Fernandez-Perez, Gabriel C; Castellon, Daniel; Calatayud, Julia; Lecumberri, Iñigo; Larrazabal, Eneritz; Ruiz, Berta Irene

    2011-08-01

    There are many disorders that may involve the left ventricular (LV) apex; however, they are sometimes difficult to differentiate. In this setting cardiac imaging methods can provide the clue to obtaining the diagnosis. The purpose of this review is to illustrate the spectrum of diseases that most frequently affect the apex of the LV including Tako-Tsubo cardiomyopathy, LV aneurysms and pseudoaneurysms, apical diverticula, apical ventricular remodelling, apical hypertrophic cardiomyopathy, LV non-compaction, arrhythmogenic right ventricular dysplasia with LV involvement and LV false tendons, with an emphasis on the diagnostic criteria and imaging features. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13244-011-0091-6) contains supplementary material, which is available to authorized users.

  12. A self-organized biomechanical network drives shape changes during tissue morphogenesis.

    Science.gov (United States)

    Munjal, Akankshi; Philippe, Jean-Marc; Munro, Edwin; Lecuit, Thomas

    2015-08-20

    Tissue morphogenesis is orchestrated by cell shape changes. Forces required to power these changes are generated by non-muscle myosin II (MyoII) motor proteins pulling filamentous actin (F-actin). Actomyosin networks undergo cycles of assembly and disassembly (pulses) to cause cell deformations alternating with steps of stabilization to result in irreversible shape changes. Although this ratchet-like behaviour operates in a variety of contexts, the underlying mechanisms remain unclear. Here we investigate the role of MyoII regulation through the conserved Rho1-Rok pathway during Drosophila melanogaster germband extension. This morphogenetic process is powered by cell intercalation, which involves the shrinkage of junctions in the dorsal-ventral axis (vertical junctions) followed by junction extension in the anterior-posterior axis. While polarized flows of medial-apical MyoII pulses deform vertical junctions, MyoII enrichment on these junctions (planar polarity) stabilizes them. We identify two critical properties of MyoII dynamics that underlie stability and pulsatility: exchange kinetics governed by phosphorylation-dephosphorylation cycles of the MyoII regulatory light chain; and advection due to contraction of the motors on F-actin networks. Spatial control over MyoII exchange kinetics establishes two stable regimes of high and low dissociation rates, resulting in MyoII planar polarity. Pulsatility emerges at intermediate dissociation rates, enabling convergent advection of MyoII and its upstream regulators Rho1 GTP, Rok and MyoII phosphatase. Notably, pulsatility is not an outcome of an upstream Rho1 pacemaker. Rather, it is a self-organized system that involves positive and negative biomechanical feedback between MyoII advection and dissociation rates.

  13. Pak3 regulates apical-basal polarity in migrating border cells during Drosophila oogenesis.

    Science.gov (United States)

    Felix, Martina; Chayengia, Mrinal; Ghosh, Ritabrata; Sharma, Aditi; Prasad, Mohit

    2015-11-01

    Group cell migration is a highly coordinated process that is involved in a number of physiological events such as morphogenesis, wound healing and tumor metastasis. Unlike single cells, collectively moving cells are physically attached to each other and retain some degree of apical-basal polarity during the migratory phase. Although much is known about direction sensing, how polarity is regulated in multicellular movement remains unclear. Here we report the role of the protein kinase Pak3 in maintaining apical-basal polarity in migrating border cell clusters during Drosophila oogenesis. Pak3 is enriched in border cells and downregulation of its function impedes border cell movement. Time-lapse imaging suggests that Pak3 affects protrusive behavior of the border cell cluster, specifically regulating the stability and directionality of protrusions. Pak3 functions downstream of guidance receptor signaling to regulate the level and distribution of F-actin in migrating border cells. We also provide evidence that Pak3 genetically interacts with the lateral polarity marker Scribble and that it regulates JNK signaling in the moving border cells. Since Pak3 depletion results in mislocalization of several apical-basal polarity markers and overexpression of Jra rescues the polarity of the Pak3-depleted cluster, we propose that Pak3 functions through JNK signaling to modulate apical-basal polarity of the migrating border cell cluster. We also observe loss of apical-basal polarity in Rac1-depleted border cell clusters, suggesting that guidance receptor signaling functions through Rac GTPase and Pak3 to regulate the overall polarity of the cluster and mediate efficient collective movement of the border cells to the oocyte boundary.

  14. ARF6 promotes the formation of Rac1 and WAVE-dependent ventral F-actin rosettes in breast cancer cells in response to epidermal growth factor.

    Directory of Open Access Journals (Sweden)

    Valentina Marchesin

    Full Text Available Coordination between actin cytoskeleton assembly and localized polarization of intracellular trafficking routes is crucial for cancer cell migration. ARF6 has been implicated in the endocytic recycling of surface receptors and membrane components and in actin cytoskeleton remodeling. Here we show that overexpression of an ARF6 fast-cycling mutant in MDA-MB-231 breast cancer-derived cells to mimick ARF6 hyperactivation observed in invasive breast tumors induced a striking rearrangement of the actin cytoskeleton at the ventral cell surface. This phenotype consisted in the formation of dynamic actin-based podosome rosette-like structures expanding outward as wave positive for F-actin and actin cytoskeleton regulatory components including cortactin, Arp2/3 and SCAR/WAVE complexes and upstream Rac1 regulator. Ventral rosette-like structures were similarly induced in MDA-MB-231 cells in response to epidermal growth factor (EGF stimulation and to Rac1 hyperactivation. In addition, interference with ARF6 expression attenuated activation and plasma membrane targeting of Rac1 in response to EGF treatment. Our data suggest a role for ARF6 in linking EGF-receptor signaling to Rac1 recruitment and activation at the plasma membrane to promote breast cancer cell directed migration.

  15. Abceso apical agudo

    OpenAIRE

    Jara Ortiz, M.; López, M.; Gómez Viglino, L.; Maydana, N.; Hervit, M.; Bertola, N.

    2015-01-01

    En casos de urgencia, muchas veces debemos poner a prueba distintos elementos de diagnóstico para encontrar la mejor respuesta posible. En este caso se reporta un absceso apical agudo en la zona palatina del sector 1, que, de acuerdo al test de vitalidad pulpar y correcta interpretación radiográfica se localiza la pieza causal N° 1.8.Asistió a la consulta un paciente masculino 30 años de edad, dolor a la masticación, edema y tumefacción, en zona palatina comprendida en piezas 1.5; 1.6; 1.7 y ...

  16. Two cases of apical ballooning syndrome masking apical hypertrophic cardiomyopathy.

    Science.gov (United States)

    Roy, Ranjini Raina; Hakim, Fayaz A; Hurst, R Todd; Simper, David; Appleton, Christopher P

    2014-04-01

    Apical akinesis and dilation in the absence of obstructive coronary artery disease is a typical feature of stress-induced (takotsubo) cardiomyopathy, whereas apical hypertrophy is seen in apical-variant hypertrophic cardiomyopathy. We report the cases of 2 patients who presented with takotsubo cardiomyopathy and were subsequently found to have apical-variant hypertrophic cardiomyopathy, after the apical ballooning from the takotsubo cardiomyopathy had resolved. The first patient, a 43-year-old woman with a history of alcohol abuse, presented with shortness of breath, electrocardiographic and echocardiographic features consistent with takotsubo cardiomyopathy, and no significant coronary artery disease. An echocardiogram 2 weeks later revealed a normal left ventricular ejection fraction and newly apparent apical hypertrophy. The 2nd patient, a 70-year-old woman with pancreatitis, presented with chest pain, apical akinesis, and a left ventricular ejection fraction of 0.39, consistent with takotsubo cardiomyopathy. One month later, her left ventricular ejection fraction was normal; however, hypertrophy of the left ventricular apex was newly noted. To our knowledge, these are the first reported cases in which apical-variant hypertrophic cardiomyopathy was masked by apical ballooning from stress-induced cardiomyopathy.

  17. F-actin-based extensions of the head cyst cell adhere to the maturing spermatids to maintain them in a tight bundle and prevent their premature release in Drosophila testis

    Directory of Open Access Journals (Sweden)

    Ray Krishanu

    2009-05-01

    Full Text Available Abstract Background In Drosophila, all the 64 clonally derived spermatocytes differentiate in syncytium inside two somatic-origin cyst cells. They elongate to form slender spermatids, which are individualized and then released into the seminal vesicle. During individualization, differentiating spermatids are organized in a tight bundle inside the cyst, which is expected to play an important role in sperm selection. However, actual significance of this process and its underlying mechanism are unclear. Results We show that dynamic F-actin-based processes extend from the head cyst cell at the start of individualization, filling the interstitial space at the rostral ends of the maturing spermatid bundle. In addition to actin, these structures contained lamin, beta-catenin, dynamin, myosin VI and several other filopodial components. Further, pharmacological and genetic analyses showed that cytoskeletal stability and dynamin function are essential for their maintenance. Disruption of these F-actin based processes was associated with spermatid bundle disassembly and premature sperm release inside the testis. Conclusion Altogether, our data suggests that the head cyst cell adheres to the maturing spermatid heads through F-actin-based extensions, thus maintaining them in a tight bundle. This is likely to regulate mature sperm release into the seminal vesicle. Overall, this process bears resemblance to mammalian spermiation.

  18. Dynamin2 organizes lamellipodial actin networks to orchestrate lamellar actomyosin.

    Directory of Open Access Journals (Sweden)

    Manisha Menon

    Full Text Available Actin networks in migrating cells exist as several interdependent structures: sheet-like networks of branched actin filaments in lamellipodia; arrays of bundled actin filaments co-assembled with myosin II in lamellae; and actin filaments that engage focal adhesions. How these dynamic networks are integrated and coordinated to maintain a coherent actin cytoskeleton in migrating cells is not known. We show that the large GTPase dynamin2 is enriched in the distal lamellipod where it regulates lamellipodial actin networks as they form and flow in U2-OS cells. Within lamellipodia, dynamin2 regulated the spatiotemporal distributions of α-actinin and cortactin, two actin-binding proteins that specify actin network architecture. Dynamin2's action on lamellipodial F-actin influenced the formation and retrograde flow of lamellar actomyosin via direct and indirect interactions with actin filaments and a finely tuned GTP hydrolysis activity. Expression in dynamin2-depleted cells of a mutant dynamin2 protein that restores endocytic activity, but not activities that remodel actin filaments, demonstrated that actin filament remodeling by dynamin2 did not depend of its functions in endocytosis. Thus, dynamin2 acts within lamellipodia to organize actin filaments and regulate assembly and flow of lamellar actomyosin. We hypothesize that through its actions on lamellipodial F-actin, dynamin2 generates F-actin structures that give rise to lamellar actomyosin and for efficient coupling of F-actin at focal adhesions. In this way, dynamin2 orchestrates the global actin cytoskeleton.

  19. Actin-interacting protein 1 controls assembly and permeability of intestinal epithelial apical junctions.

    Science.gov (United States)

    Lechuga, Susana; Baranwal, Somesh; Ivanov, Andrei I

    2015-05-01

    Adherens junctions (AJs) and tight junctions (TJs) are crucial regulators of the integrity and restitution of the intestinal epithelial barrier. The structure and function of epithelial junctions depend on their association with the cortical actin cytoskeleton that, in polarized epithelial cells, is represented by a prominent perijunctional actomyosin belt. The assembly and stability of the perijunctional cytoskeleton is controlled by constant turnover (disassembly and reassembly) of actin filaments. Actin-interacting protein (Aip) 1 is an emerging regulator of the actin cytoskeleton, playing a critical role in filament disassembly. In this study, we examined the roles of Aip1 in regulating the structure and remodeling of AJs and TJs in human intestinal epithelium. Aip1 was enriched at apical junctions in polarized human intestinal epithelial cells and normal mouse colonic mucosa. Knockdown of Aip1 by RNA interference increased the paracellular permeability of epithelial cell monolayers, decreased recruitment of AJ/TJ proteins to steady-state intercellular contacts, and attenuated junctional reassembly in a calcium-switch model. The observed defects of AJ/TJ structure and functions were accompanied by abnormal organization and dynamics of the perijunctional F-actin cytoskeleton. Moreover, loss of Aip1 impaired the apico-basal polarity of intestinal epithelial cell monolayers and inhibited formation of polarized epithelial cysts in 3-D Matrigel. Our findings demonstrate a previously unanticipated role of Aip1 in regulating the structure and remodeling of intestinal epithelial junctions and early steps of epithelial morphogenesis.

  20. Multiple actin binding domains of Ena/VASP proteins determine actin network stiffening.

    Science.gov (United States)

    Gentry, Brian S; van der Meulen, Stef; Noguera, Philippe; Alonso-Latorre, Baldomero; Plastino, Julie; Koenderink, Gijsje H

    2012-11-01

    Vasodilator-stimulated phosphoprotein (Ena/VASP) is an actin binding protein, important for actin dynamics in motile cells and developing organisms. Though VASP's main activity is the promotion of barbed end growth, it has an F-actin binding site and can form tetramers, and so could additionally play a role in actin crosslinking and bundling in the cell. To test this activity, we performed rheology of reconstituted actin networks in the presence of wild-type VASP or mutants lacking the ability to tetramerize or to bind G-actin and/or F-actin. We show that increasing amounts of wild-type VASP increase network stiffness up to a certain point, beyond which stiffness actually decreases with increasing VASP concentration. The maximum stiffness is 10-fold higher than for pure actin networks. Confocal microscopy shows that VASP forms clustered actin filament bundles, explaining the reduction in network elasticity at high VASP concentration. Removal of the tetramerization site results in significantly reduced bundling and bundle clustering, indicating that VASP's flexible tetrameric structure causes clustering. Removing either the F-actin or the G-actin binding site diminishes VASP's effect on elasticity, but does not eliminate it. Mutating the F-actin and G-actin binding site together, or mutating the F-actin binding site and saturating the G-actin binding site with monomeric actin, eliminates VASP's ability to increase network stiffness. We propose that, in the cell, VASP crosslinking confers only moderate increases in linear network elasticity, and unlike other crosslinkers, VASP's network stiffening activity may be tuned by the local concentration of monomeric actin.

  1. 宿主细胞F-actin聚集在顶复门原虫入侵过程中的作用研究%A Role for Host Cell F-actin Polymerization during the Protozoan Parasite Infection

    Institute of Scientific and Technical Information of China (English)

    吴彩艳; 王祯; 李娟; 林栩慧; 廖申权; 戚南山; 吕敏娜; 孙铭飞

    2016-01-01

    病原入侵宿主细胞,由宿主细胞肌动蛋白(F actin)聚集引起的细胞骨架重排起着极其重要的作用,本文主要就宿主细胞整合素介导的宿主细胞F-actin聚集重排在顶复门原虫入侵过程中的作用进行系统的阐述,对解析顶复门原虫的入侵机制及以此研制新型寄生虫病药物和疫苗具有非常重要的意义.

  2. 阿魏酸对兔受损窦房结细胞骨架F-actin、Vinculin的影响%Impacts of Ferulic Acid in F-actin and Vinculin of Cytoskeleton in Dam-aged Atrionector of Rabbits

    Institute of Scientific and Technical Information of China (English)

    刘如秀; 彭杰; 刘宇; 刘金凤; 汪艳丽

    2015-01-01

    目的:观察阿魏酸对模拟缺血再灌注损伤兔窦房结细胞骨架蛋白F-actin和Vinculin的影响,探讨其保护窦房结细胞的机制。方法取新生乳兔窦房结细胞,以缺氧缺糖模拟缺血,以恢复氧和糖的供应模拟再灌注造成窦房结细胞损伤模型。正常对照组与模型组给予等体积培养基,阿魏酸高、中、低剂量组分别给予相应浓度药物(终浓度分别为100μmol/ml、20μmol/ml、10μmol/ml),运用酶标仪、激光共聚焦显微镜观察各组窦房结细胞活性、细胞骨架蛋白F-actin和Vinculin形态的变化。结果模型组活细胞量较正常对照组明显减少(P<0.01);细胞骨架蛋白F-actin和Vinculin裂解明显。阿魏酸高、中、低剂量组活细胞量明显高于模型组(P<0.01),F-actin和Vinculin结构较模型组明显完整,平均荧光强度明显高于模型组( P<0.01)。结论阿魏酸可抑制模拟缺血再灌注引起的窦房结细胞损伤;阿魏酸保护窦房结细胞的机制可能与保护细胞骨架蛋白F-actin和Vinculin从而维持细胞电生理稳定有关。%Objective To observe the impact of ferulic acid in F-actin and Vinculin of cytoskele-ton in the rabbits with damaged atrionector of ischemic reperfusion and explore its protective mechanism on atrionector cells. Methods The atrionector cells of newly born rabbits were collected. The ischemia was sim-ulated with deprivation of oxygen and glucose. The reperfusion was simulated with recovery of oxygen and glu-cose. The same volume medium was used in the normal control group and the model group. The medicine of corresponding concentrations was used in ferulic acid high dose group,middle dose group and low dose group ( the final concentration was 100 μmol/ml,20 μmol/ml or 10 μmol/ml). ELIASA and laser scanning confo-cal microscope were used to observe the changes of atrionector cell activity and F-actin and Vinculin of cy-toskeleton. Results The

  3. A synthetic mechano-growth factor E peptide promotes rat tenocyte migration by lessening cell stiffness and increasing F-actin formation via the FAK-ERK1/2 signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bingyu [Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Luo, Qing, E-mail: qing.luo@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Mao, Xinjian [Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Xu, Baiyao [Department of Mechanical Science and Engineering, Nagoya University, Nagoya 464-8603 (Japan); Yang, Li [Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Ju, Yang [Department of Mechanical Science and Engineering, Nagoya University, Nagoya 464-8603 (Japan); Song, Guanbin, E-mail: song@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China)

    2014-03-10

    Tendon injuries are common in sports and are frequent reasons for orthopedic consultations. The management of damaged tendons is one of the most challenging problems in orthopedics. Mechano-growth factor (MGF), a recently discovered growth repair factor, plays positive roles in tissue repair through the improvement of cell proliferation and migration and the protection of cells against injury-induced apoptosis. However, it remains unclear whether MGF has the potential to accelerate tendon repair. We used a scratch wound assay in this study to demonstrate that MGF-C25E (a synthetic mechano-growth factor E peptide) promotes the migration of rat tenocytes and that this promotion is accompanied by an elevation in the expression of the following signaling molecules: focal adhesion kinase (FAK) and extracellular signal regulated kinase1/2 (ERK1/2). Inhibitors of the FAK and ERK1/2 pathways inhibited the MGF-C25E-induced tenocyte migration, indicating that MGF-C25E promotes tenocyte migration through the FAK-ERK1/2 signaling pathway. The analysis of the mechanical properties showed that the Young's modulus of tenocytes was decreased through treatment of MGF-C25E, and an obvious formation of pseudopodia and F-actin was observed in MGF-C25E-treated tenocytes. The inhibition of the FAK or ERK1/2 signals restored the decrease in Young's modulus and inhibited the formation of pseudopodia and F-actin. Overall, our study demonstrated that MGF-C25E promotes rat tenocyte migration by lessening cell stiffness and increasing pseudopodia formation via the FAK-ERK1/2 signaling pathway. - Highlights: • Mechano-growth factor E peptide (MGF-C25E) promotes migration of rat tenocytes. • MGF-C25E activates the FAK-ERK1/2 pathway in rat tenocytes. • MGF-C25E induces the actin remodeling and the formation of pseudopodia, and decreases the stiffness in rat tenocytes. • MGF-C25E promotes tenocyte migration via altering stiffness and forming pseudopodia by the activation of the

  4. Apical constriction: themes and variations on a cellular mechanism driving morphogenesis.

    Science.gov (United States)

    Martin, Adam C; Goldstein, Bob

    2014-05-01

    Apical constriction is a cell shape change that promotes tissue remodeling in a variety of homeostatic and developmental contexts, including gastrulation in many organisms and neural tube formation in vertebrates. In recent years, progress has been made towards understanding how the distinct cell biological processes that together drive apical constriction are coordinated. These processes include the contraction of actin-myosin networks, which generates force, and the attachment of actin networks to cell-cell junctions, which allows forces to be transmitted between cells. Different cell types regulate contractility and adhesion in unique ways, resulting in apical constriction with varying dynamics and subcellular organizations, as well as a variety of resulting tissue shape changes. Understanding both the common themes and the variations in apical constriction mechanisms promises to provide insight into the mechanics that underlie tissue morphogenesis.

  5. Effects of oridonin on cytoskeletal protein F-actin in human pancreatic carcinoma cells%冬凌草甲素对胰腺癌细胞骨架蛋白F-actin的影响

    Institute of Scientific and Technical Information of China (English)

    刘军楼; 沈洪; 徐力; 杨继兵; 于希忠; 孙志岭

    2015-01-01

    Background and purpose:Traditional Chinese medicine with notable effect and little adverse reaction is increasingly concerned about the medical profession because of its great potential and advantage in treating pancreatic carcinoma. In this experiment, we studied the effects of oridonin on apoptosis and cytoskeletal protein F-actin in human pancreatic carcinoma SW1990 cells. Methods:SW1990 cells in culture medium were treated with different concentrations of oridonin. The inhibitory rate of the cells was measured by MTT assay. Morphology of cell apoptosis was observed by DAPI stain and cell apoptotic rate was detected by lfow cytometry (FCM). The morphological changes of F-actin were observed by laser confocal microscopy. Results:The growth of human pancreatic carcinoma SW1990 cells was signiifcantly inhibited by oridonin. Apoptosis morphological changes including condensation of chromatin and nuclear fragmentation were observed clearly by DAPI stain. The early apoptotic rate of SW1990 cells treated with 25, 50μmol/L oridonin was signiifcantly higher than that of the control group (3.78±0.46, 9.51±0.63 vs 0.73±0.06, P<0.05), and the late apoptotic rate and cell necrosis rate were also signiifcantly higher than that of the control group (14.40±1.78, 20.53±2.54 vs 4.16±0.31, P<0.05). F-actin was showed from polymerization to depolymerization after oridonin treatment. Conclusion:Oridonin can obviously inhibit the proliferation and induce apoptosis of SW1990 cells. The mechanisms may involve the depolymerization of F-actin after treatment with oridonin.%背景与目的:中医药治疗肿瘤不良反应低且疗效显著,在防治胰腺癌方面有较大的潜力与优势,日益受到国内、外医学界的关注。本研究观察中草药冬凌草的有效成分冬凌草甲素对人胰腺癌SW1990凋亡及细胞骨架蛋白F-actin的影响。方法:以不同浓度的冬凌草甲素作用于体外培养的SW1990细胞,采用MTT法检测细胞生长

  6. A semi-flexible model prediction for the polymerization force exerted by a living F-actin filament on a fixed wall

    CERN Document Server

    Pierleoni, Carlo; Ryckaert, Jean-Paul

    2015-01-01

    We consider a single living semi-flexible filament with persistence length l_p in chemical equilibrium with an ideal solution of free monomers at fixed monomer chemical potential mu_1 and fixed temperature T. While one end of the filament is chemically active with single monomer (de)polymerization steps, the other end is grafted normally to a rigid wall to mimick a rigid network from which the filament under consideration emerges. A second rigid wall, parallel to the grafting wall, is fixed at distance L<

  7. Mechanics of composite cytoskeletal and extracellular networks

    Science.gov (United States)

    Das, Moumita

    2014-03-01

    Living cells sense and respond to mechanical forces in their surroundings. This mechanical response is mainly due to the cell cytoskeleton, and its interaction with the extracellular matrix (ECM). The cell cytoskeleton is a composite polymeric scaffold made of many different types of protein filaments and crosslinking proteins. Two major filament systems in the cytoskeleton are actin filaments (F-actin) and microtubules (MTs). Actin filaments are semiflexible, while the much stiffer MTs behave as rigid rods. I shall discuss theories that help understand how the direct coupling to the surrounding F-actin matrix allows intracellular MTs to bear large compressive forces and controls the range of force transmission along the MTs, and how the MTs not only enhance the stiffness of the cell cytoskeleton, but can also dramatically endow an initially nearly incompressible F-actin matrix with enhanced compressibility relative to its shear compliance. A second source of compositeness in the cytoskeleton is the presences of different types of crosslinkers that can interact cooperatively leading to enhanced mechanical rigidity and tunable response. Like the cytoskeleton, the ECM is also a polymeric composite. It is primarily composed of a mesh of fibrous proteins, mainly stiff collagen filaments, and a comparatively flexible gel of proteoglycans and hyaluronan. I shall discuss a model that shows how the interplay between the collagen network and the background elastic gel leads to a mechanically robust ECM.

  8. A Comparative Study of Apical Healing of Open Apices Using MTA and Ca(OH2 Apical Plugs in Cats

    Directory of Open Access Journals (Sweden)

    M. H. Zarrabi

    2005-06-01

    Full Text Available Statement of problem: Endodontic treatment of necrotic teeth with open apices is a challenge. After ruling out surgery as a treatment scheme and introduction of the multivisit apexification which in turn had its disadvantages, apical plug seems to be a suitable substitute treatment plan for such cases. Apical plug makes the treatment through formation of a barrier against the obturating material in a single visit.Purpose: The purpose of this study was to compare histologically the periapical healing using MTA and calcium hydroxide apical plugs after intervals of 4 and 12 weeks in cats.Materials and Methods: In this clinical trial study 64 canines of 16 healthy and mature cats were divided into 3 groups after a periapical lesion formation by over instrumentation in the apical area with files up to no.120. The first group included 24 teeth on which MTA apical plug was applied. The second group included 24 teeth on which Ca (OH 2 apical plug was applied. In both groups the canals were filled with gutta percha and sealer. The third group included 16 control teeth whose canals were left empty after instrumentation and debridement. The access cavities of all teeth were sealed with varnish and amalgam and the vital perfusion of cats was performed in 4 and 12 week intervals. Statistical analysis was established by χ2 and independence test.Results: After 4 weeks, periapical healing in the first group was 90%, in the second group 80% and in the third group, it was only 12.5 %. After 12 weeks, periapical healing occurred in 100% of the MTA group, while it was 57.1% in the second and 40%in the third group .Generally, in the study of histological parameters of healing, no statistical significant difference was observed between the 2 experimental groups,although the MTA group results were much better than the Ca (OH 2 group especially at 12 weeks.Conclusion: The use of MTA apical plug is more effective than Ca (OH 2 in treatment of necrotic teeth with open

  9. Apical root resorption in orthodontically treated adults.

    Science.gov (United States)

    Baumrind, S; Korn, E L; Boyd, R L

    1996-09-01

    This study analyzed the relationship in orthodontically treated adults between upper central incisor displacement measured on lateral cephalograms and apical root resorption measured on anterior periapical x-ray films. A multiple linear regression examined incisor displacements in four directions (retraction, advancement, intrusion, and extrusion) as independent variables, attempting to account for observed differences in the dependent variable, resorption. Mean apical resorption was 1.36 mm (sd +/- 1.46, n = 73). Mean horizontal displacement of the apex was -0.83 mm (sd +/- 1.74, n = 67); mean vertical displacement was 0.19 mm (sd +/- 1.48, n = 67). The regression coefficients for the intercept and for retraction were highly significant; those for extrusion, intrusion, and advancement were not. At the 95% confidence level, an average of 0.99 mm (se = +/- 0.34) of resorption was implied in the absence of root displacement and an average of 0.49 mm (se = +/- 0.14) of resorption was implied per millimeter of retraction. R2 for all four directional displacement variables (DDVs) taken together was only 0.20, which implied that only a relatively small portion of the observed apical resorption could be accounted for by tooth displacement alone. In a secondary set of univariate analyses, the associations between apical resorption and each of 14 additional treatment-related variables were examined. Only Gender, Elapsed Time, and Total Apical Displacement displayed statistically significant associations with apical resorption. Additional multiple regressions were then performed in which the data for each of these three statistically significant variables were considered separately, with the data for the four directional displacement variables. The addition of information on Elapsed Time or Total Apical Displacement did not explain a significant additional portion of the variability in apical resorption. On the other hand, the addition of information on Gender to the

  10. Disordered actomyosin networks are sufficient to produce cooperative and telescopic contractility

    Science.gov (United States)

    Linsmeier, Ian; Banerjee, Shiladitya; Oakes, Patrick W.; Jung, Wonyeong; Kim, Taeyoon; Murrell, Michael P.

    2016-08-01

    While the molecular interactions between individual myosin motors and F-actin are well established, the relationship between F-actin organization and actomyosin forces remains poorly understood. Here we explore the accumulation of myosin-induced stresses within a two-dimensional biomimetic model of the disordered actomyosin cytoskeleton, where myosin activity is controlled spatiotemporally using light. By controlling the geometry and the duration of myosin activation, we show that contraction of disordered actin networks is highly cooperative, telescopic with the activation size, and capable of generating non-uniform patterns of mechanical stress. We quantitatively reproduce these collective biomimetic properties using an isotropic active gel model of the actomyosin cytoskeleton, and explore the physical origins of telescopic contractility in disordered networks using agent-based simulations.

  11. Cell division activity during apical hook development

    NARCIS (Netherlands)

    Raz, V.; Koornneef, M.

    2001-01-01

    Growth during plant development is predominantly governed by the combined activities of cell division and cell elongation. The relative contribution of both activities controls the growth of a tissue. A fast change in growth is exhibited at the apical hypocotyl of etiolated seedlings where cells gro

  12. Nuclear factor of activated T cells c1 mediates p21-activated kinase 1 activation in the modulation of chemokine-induced human aortic smooth muscle cell F-actin stress fiber formation, migration, and proliferation and injury-induced vascular wall remodeling.

    Science.gov (United States)

    Kundumani-Sridharan, Venkatesh; Singh, Nikhlesh K; Kumar, Sanjay; Gadepalli, Ravisekhar; Rao, Gadiparthi N

    2013-07-26

    Recent literature suggests that cyclin-dependent kinases (CDKs) mediate cell migration. However, the mechanisms were not known. Therefore, the objective of this study is to test whether cyclin/CDKs activate Pak1, an effector of Rac1, whose involvement in the modulation of cell migration and proliferation is well established. Monocyte chemotactic protein 1 (MCP1) induced Pak1 phosphorylation/activation in human aortic smooth muscle cells (HASMCs) in a delayed time-dependent manner. MCP1 also stimulated F-actin stress fiber formation in a delayed manner in HASMCs, as well as the migration and proliferation of these cells. Inhibition of Pak1 suppressed MCP1-induced HASMC F-actin stress fiber formation, migration, and proliferation. MCP1 induced cyclin D1 expression as well as CDK6 and CDK4 activities, and these effects were dependent on activation of NFATc1. Depletion of NFATc1, cyclin D1, CDK6, or CDK4 levels attenuated MCP1-induced Pak1 phosphorylation/activation and resulted in decreased HASMC F-actin stress fiber formation, migration, and proliferation. CDK4, which appeared to be activated downstream of CDK6, formed a complex with Pak1 in response to MCP1. MCP1 also activated Rac1 in a time-dependent manner, and depletion/inhibition of its levels/activation abrogated MCP1-induced NFATc1-cyclin D1-CDK6-CDK4-Pak1 signaling and, thereby, decreased HASMC F-actin stress fiber formation, migration, and proliferation. In addition, smooth muscle-specific deletion of NFATc1 led to decreased cyclin D1 expression and CDK6, CDK4, and Pak1 activities, resulting in reduced neointima formation in response to injury. Thus, these observations reveal that Pak1 is a downstream effector of CDK4 and Rac1-dependent, NFATc1-mediated cyclin D1 expression and CDK6 activity mediate this effect. In addition, smooth muscle-specific deletion of NFATc1 prevented the capacity of vascular smooth muscle cells for MCP-1-induced activation of the cyclin D1-CDK6-CDK4-Pak1 signaling axis, affecting

  13. Apical domain polarization localizes actin-myosin activity to drive ratchet-like apical constriction

    OpenAIRE

    Mason, Frank M.; Tworoger, Michael; Martin, Adam C.

    2013-01-01

    Apical constriction promotes epithelia folding, which changes tissue architecture. During Drosophila gastrulation, mesoderm cells exhibit repeated contractile pulses that are stabilized such that cells apically constrict like a ratchet. The transcription factor Twist is required to stabilize cell shape, however it is unknown how Twist spatially coordinates downstream signals to prevent cell relaxation. We find that during constriction, Rho-associated kinase (Rok) is polarized to the middle of...

  14. Microbiome in the Apical Root Canal System of Teeth with Post-Treatment Apical Periodontitis

    Science.gov (United States)

    Siqueira, José F.; Antunes, Henrique S.; Rôças, Isabela N.; Rachid, Caio T. C. C.

    2016-01-01

    Introduction Bacteria present in the apical root canal system are directly involved with the pathogenesis of post-treatment apical periodontitis. This study used a next-generation sequencing approach to identify the bacterial taxa occurring in cryopulverized apical root samples from root canal-treated teeth with post-treatment disease. Methods Apical root specimens obtained during periradicular surgery of ten adequately treated teeth with persistent apical periodontitis were cryogenically ground. DNA was extracted from the powder and the microbiome was characterized on the basis of the V4 hypervariable region of the 16S rRNA gene by using paired-end sequencing on Illumina MiSeq device. Results All samples were positive for the presence of bacterial DNA. Bacterial taxa were mapped to 11 phyla and 103 genera composed by 538 distinct operational taxonomic units (OTUs) at 3% of dissimilarity. Over 85% of the sequences belonged to 4 phyla: Proteobacteria, Firmicutes, Fusobacteria and Actinobacteria. In general, these 4 phyla accounted for approximately 80% of the distinct OTUs found in the apical root samples. Proteobacteria was the most abundant phylum in 6/10 samples. Fourteen genera had representatives identified in all cases. Overall, the genera Fusobacterium and Pseudomonas were the most dominant. Enterococcus was found in 4 cases, always in relatively low abundance. Conclusions This study showed a highly complex bacterial community in the apical root canal system of adequately treated teeth with persistent apical periodontitis. This suggests that this disease is characterized by multispecies bacterial communities and has a heterogeneous etiology, because the community composition largely varied from case to case. PMID:27689802

  15. The nucleocytoplasmic microfilament network in protoplasts from cultured soybean cells is a plastic entity that pervades the cytoplasm except the central vacuole.

    Science.gov (United States)

    Villanueva, Marco A; Schindler, Melvin; Wang, John L

    2005-11-01

    The microfilament network of cultured Glycine max cells (SB-1 line), and protoplasts was visualized with rhodamine-phalloidin under conditions that lysed the protoplast and changed the cell shape. The whole cell had the typical microfilament distribution of a "cage" around the nucleus, from which the large subcortical cables and transvacuolar strands radiated towards the cortex until it reached the cortical microfilament network. Upon cell wall removal, the network conserved its compartmentalization. Thus, the redistribution of the shape where the vacuole becomes a central entity, made the cytoplasm displace peripherally, but the network distribution was conserved. When protoplasts were lysed in a low osmotic medium, the vacuoles were gradually released intact. Under these conditions, the F-actin staining remained within the ghost of the cell, but none was detected in either emerging or almost completely released vacuoles. Most of the released F-actin was found in debris from the cell lysate in the form of microfilaments. When the ghosts were constrained in a coverslip with an air bubble, the shape of the ghost changed accordingly, but the microfilament network distribution remained constant. These results provide further evidence that the vacuole of plant cells does not have detectable associated F-actin. In addition, we demonstrate that the actin microfilament network is a moldable entity that can change its shape but keeps its distribution under constant conditions, in these cultured cells.

  16. Type III apical transportation of root canal

    Directory of Open Access Journals (Sweden)

    Shiv P Mantri

    2012-01-01

    Full Text Available Procedural accidents leading to complications such as canal transportation have been ascribed to inapt cleaning and shaping concepts. Canal transportation is an undesirable deviation from the natural canal path. Herewith a case of apical transportation of root canal resulting in endodontic retreatment failure and its management is presented. A healthy 21-year-old young male presented discomfort and swelling associated with painful endodontically retreated maxillary incisor. Radiograph revealed periradicular radiolucency involving underfilled 11 and overfilled 12. Insufficiently obturated 11 exhibited apical transportation of canal. This type III transportation was treated by periradicular surgery and repair using white mineral trioxide aggregate (MTA. Comfortable asymptomatic patient presented uneventful healing at third and fourth month recall visits. A decrease in the size of radiolucency in radiograph supported the clinical finding. In the present case, MTA is useful in repairing the transportation defect. The result of these procedures is predictable and successful.

  17. Evaluation of three instrumentation techniques at the precision of apical stop and apical sealing of obturation

    Science.gov (United States)

    GENÇ, Özgür; ALAÇAM, Tayfun; KAYAOGLU, Guven

    2011-01-01

    Objective The aim of this study was to investigate the ability of two NiTi rotary apical preparation techniques used with an electronic apex locator-integrated endodontic motor and a manual technique to create an apical stop at a predetermined level (0.5 mm short of the apical foramen) in teeth with disrupted apical constriction, and to evaluate microleakage following obturation in such prepared teeth. Material and Methods: 85 intact human mandibular permanent incisors with single root canal were accessed and the apical constriction was disrupted using a #25 K-file. The teeth were embedded in alginate and instrumented to #40 using rotary Lightspeed or S-Apex techniques or stainless-steel K-files. Distance between the apical foramen and the created apical stop was measured to an accuracy of 0.01 mm. In another set of instrumented teeth, root canals were obturated using gutta-percha and sealer, and leakage was tested at 1 week and 3 months using a fluid filtration device. Results All techniques performed slightly short of the predetermined level. Closest preparation to the predetermined level was with the manual technique and the farthest was with S-Apex. A significant difference was found between the performances of these two techniques (p<0.05). Lightspeed ranked in between. Leakage was similar for all techniques at either period. However, all groups leaked significantly more at 3 months compared to 1 week (p<0.05). Conclusions Despite statistically significant differences found among the techniques, deviations from the predetermined level were small and clinically acceptable for all techniques. Leakage following obturation was comparable in all groups. PMID:21655774

  18. Evaluation of three instrumentation techniques at the precision of apical stop and apical sealing of obturation

    Directory of Open Access Journals (Sweden)

    Özgür Genç

    2011-08-01

    Full Text Available OBJECTIVE: The aim of this study was to investigate the ability of two NiTi rotary apical preparation techniques used with an electronic apex locator-integrated endodontic motor and a manual technique to create an apical stop at a predetermined level (0.5 mm short of the apical foramen in teeth with disrupted apical constriction, and to evaluate microleakage following obturation in such prepared teeth. MATERIAL AND METHODS: 85 intact human mandibular permanent incisors with single root canal were accessed and the apical constriction was disrupted using a #25 K-file. The teeth were embedded in alginate and instrumented to #40 using rotary Lightspeed or S-Apex techniques or stainless-steel K-files. Distance between the apical foramen and the created apical stop was measured to an accuracy of 0.01 mm. In another set of instrumented teeth, root canals were obturated using gutta-percha and sealer, and leakage was tested at 1 week and 3 months using a fluid filtration device. RESULTS: All techniques performed slightly short of the predetermined level. Closest preparation to the predetermined level was with the manual technique and the farthest was with S-Apex. A significant difference was found between the performances of these two techniques (p<0.05. Lightspeed ranked in between. Leakage was similar for all techniques at either period. However, all groups leaked significantly more at 3 months compared to 1 week (p<0.05. CONCLUSIONS: Despite statistically significant differences found among the techniques, deviations from the predetermined level were small and clinically acceptable for all techniques. Leakage following obturation was comparable in all groups.

  19. Pathogenesis of Apical Periodontitis: a Literature Review

    OpenAIRE

    2012-01-01

    ABSTRACT Objectives This review article discusses the host response in apical periodontitis with the main focus on cytokines, produced under this pathological condition and contributing to the degradation of periradicular tissues. The pace of research in this field has greatly accelerated in the last decade. Here we provide an analysis of studies published in this area during this period. Material and methods Literature was selected through a search of PubMed electronic database. The keywords...

  20. Growth and development of the root apical meristem.

    Science.gov (United States)

    Perilli, Serena; Di Mambro, Riccardo; Sabatini, Sabrina

    2012-02-01

    A key question in plant developmental biology is how cell division and cell differentiation are balanced to modulate organ growth and shape organ size. In recent years, several advances have been made in understanding how this balance is achieved during root development. In the Arabidopsis root meristem, stem cells in the apical region of the meristem self-renew and produce daughter cells that differentiate in the distal meristem transition zone. Several factors have been implicated in controlling the different functional zones of the root meristem to modulate root growth; among these, plant hormones have been shown to play a main role. In this review, we summarize recent findings regarding the role of hormone signaling and transcriptional networks in regulating root development.

  1. Architecture of apical dendrites in the murine neocortex: dual apical dendritic systems.

    Science.gov (United States)

    Escobar, M I; Pimienta, H; Caviness, V S; Jacobson, M; Crandall, J E; Kosik, K S

    1986-04-01

    A monoclonal antibody (5F9) against microtubule-associated protein 2 is a selective and sensitive marker for neocortical dendrites in the mouse. The marker stains all dendrites. It affords a particularly comprehensive picture of the patterns of arrangements of apical dendrites which are most intensely stained with this antibody. Dual systems of apical dendrites arise from the polymorphic neurons of layer VI, on the one hand, and the pyramidal neurons of layers II-V, on the other. Terminal arborization of the former is concentrated principally at the interface of layers V and IV, while that of the latter is in the molecular layer. Apical dendrites of both systems are grouped into fascicles. In supragranular layers and in upper layer VI-lower layer V, where apical dendrites are most abundant, the fascicles coalesce into septa. These generate a honeycomb-like pattern, subdividing these cortical levels into columnar spaces of approximately 20-40 micron diameter. At the level of layer IV, where the number of apical dendrites is greatly reduced, the fascicles are isolated bundles. These bundles have the form of circular, elliptical or rectangular columns in the primary somatosensory, temporal and frontal regions, respectively. Those in the barrel field are preferentially concentrated in the sides of barrels and the interbarrel septa. The configurations of the dendritic fascicles, particularly the midcortical bundles, may conform to the spatial configuration of investing axons of interneurons.

  2. 系统性红斑狼疮患者外周血B细胞脂筏及细胞骨架蛋白的表达初探%Study on the expression of lipid rafts and F-actin in peripheral blood B lymphocytes from patients with systemic lupus erythematosus

    Institute of Scientific and Technical Information of China (English)

    何德宁; 董光富; 张晓; 张光锋; 谢悦胜; 李玲; 雷云霞

    2012-01-01

    Objective To investigate the expression of lipid rafts (LRs) and actin cytoskeleton (F-actin) in the peripheral blood B lymphocytes of patients with systemic lupus erythematosus (SLE).Methods Peripheral blood mononuclear cells (PBMCs) were separated by Ficoll-Hypaque.B lymphocytes were isolated by positive selection from PBMCs.Membrane staining for LRs was achieved with FITC-conjugated cholera toxin B (CTB).The level and distribution of LRs were studied by flow cytometry and confocal microscopy.Staining for F-actin was carried out with Rhodamine phalloidin.The expression of F-actin was analyzed by confocal microscopy.In an in vitro examination,the effect of Leflunomide on lipid rafts in B lymphocytes from SLE was analyzed.Disease carried out was measured using the SLE disease activity index (SLEDAI).Analysis of the enumerical data was performed using ANOVA or paired-samples t test.Correlation was examined by Pearson's rank correlation test.Results The number of CTB-binding lipid rafts in B cell from active SLE patients or from SLE patients in disease remission.who were treated with immunosuppressive drugs was higher than B cells from healthy controls [(59+4)%,(51±5)%,(33±4)%,F=9.21,P=0.001].Confocal microscopy revealed that in B cell from healthy controls,lipid raft was found to be small and uniformly distributed on the plasma membrane.F-actin was found mainly in the cortical region of the cells.This pattern was different from the pattern seen in B cells from patients with SLE,which presented with stronger staining and irregular large clustering of LRs,with a decrease in F-actin levels.In addition,the number of CTB-binding LRs in B cells from the active SLE patients was correlated significantly with the SLEDAI score (r=0.632,P=0.028).Furthermore,thein vitro results showed that leflunomide treatment reduced the number of CTB-binding LRs in B cell from SLE patients [(48±5)% vs (39±5)%,t=2.29,P=0.048].Conclusion The altered expression of Lipid raft and F-actin

  3. Multimodality imaging in apical hypertrophic cardiomyopathy

    Institute of Scientific and Technical Information of China (English)

    Rosario; Parisi; Francesca; Mirabella; Gioel; Gabrio; Secco; Rossella; Fattori

    2014-01-01

    Apical hypertrophic cardiomyopathy(AHCM) is a relatively rare morphologic variant of HCM in which the hypertrophy of myocardium is localized to the left ventricular apex. Symptoms of AHCM might vary from none to others mimic coronary artery disease including acute coronary syndrome, thus resulting in inappropriate hospitalization. Transthoracic echocardiography is the firstline imaging technique for the diagnosis of hypertrophic cardiomyopathies. However, when the hypertrophy of the myocardium is localized in the ventricular apex might results in missed diagnosis. Aim of this paper is to review the different imaging techniques used for the diagnosis of AHCM and their role in the detection and comprehension of this uncommon disease.

  4. Apical-dominant particle swarm optimization

    Institute of Scientific and Technical Information of China (English)

    Zhihua Cui; Xingjuan Cai; Jianchao Zeng; Guoji Sun

    2008-01-01

    Particle swarm optimization (PSO) is a new stochastic population-based search methodology by simulating the animal social behaviors such as birds flocking and fish schooling.Many improvements have been proposed within the framework of this biological assumption.However,in this paper,the search pattern of PSO is used to model the branch growth process of natural plants.It provides a different poten-tial manner from artificial plant.To illustrate the effectiveness of this new model,apical dominance phenomenon is introduced to construct a novel variant by emphasizing the influence of the phototaxis.In this improvement,the population is divided into three different kinds of buds associated with their performances.Furthermore,a mutation strategy is applied to enhance the ability escaping from a local optimum.Sim-ulation results demonstrate good performance of the new method when solving high-dimensional multi-modal problems.

  5. Reversible transient apical ballooning syndrome with coronary lesions

    Institute of Scientific and Technical Information of China (English)

    Yunshan Cao; Min Zhang; Xiang Li; Ping Xie; Lynn Cronin

    2009-01-01

    Transient apical ballooning syndrome(Tako-Tsubo syndrome or ampulla cardiomyopathy) occurs predominantly in women over 60 years of age with a history of recent physical or psychological stress. We present a case of a male patient with reversible transient apical ballooning syndrome with significant coronary lesions and other ECG changes that did not explain the clinical symptoms.

  6. Apical Hypertrophic Cardiomyopathy in Association with PulmonaryArtery Hypertension

    Directory of Open Access Journals (Sweden)

    Mehdi Peighambari

    2012-09-01

    Full Text Available Apical Hypertrophic Cardiomyopathy is an uncommon condition constituting 1% -2% of the cases with Hypertrophic Cardiomyopathy (HCM diagnosis. We interestingly report two patients with apical hypertrophic cardiomyopathy in association with significant pulmonary artery hypertension without any other underlying reason for pulmonary hypertension. The patients were assessed by echocardiography, cardiac catheterization and pulmonary function parameters study.

  7. Virus interaction with the apical junctional complex.

    Science.gov (United States)

    Gonzalez-Mariscal, Lorenza; Garay, Erika; Lechuga, Susana

    2009-01-01

    In order to infect pathogens must breach the epithelial barriers that separate the organism from the external environment or that cover the internal cavities and ducts of the body. Epithelia seal the passage through the paracellular pathway with the apical junctional complex integrated by tight and adherens junctions. In this review we describe how viruses like coxsackie, swine vesicular disease virus, adenovirus, reovirus, feline calcivirus, herpes viruses 1 and 2, pseudorabies, bovine herpes virus 1, poliovirus and hepatitis C use as cellular receptors integral proteins present at the AJC of epithelial cells. Interaction with these proteins contributes in a significant manner in defining the particular tropism of each virus. Besides these proteins, viruses exhibit a wide range of cellular co-receptors among which proteins present in the basolateral cell surface like integrins are often found. Therefore targeting proteins of the AJC constitutes a strategy that might allow viruses to bypass the physical barrier that blocks their access to receptors expressed on the basolateral surface of epithelial cells.

  8. Maxillary first premolars: I. Morphology of the apical constriction

    Institute of Scientific and Technical Information of China (English)

    Daming Wu; Younong Wu; Ming Hu

    2009-01-01

    Objective: To investigated the apical constriction morphology of maxillary first premolars in the Chinese population. Methods: Eighty recently extracted human maxillary first premolars from a native Chinese population were used. The number and shape of apical constrictions were recorded under a dental operating microscope (DOM) at 12.5X2.5 magnification. After access preparation, a new K-file was inserted into the canal until the tip of the file was just seen at the apical constriction under the DOM. The teeth with files in the canals were X-rayed from a mesiodistal direction using a direct digital radiography (DDR) system, and the distance between the file tip and the center of radiographic apex was directly measured from the computer screen using DDR measurement software. Results: The percentage of teeth with an apical constriction was 78.5% (102/130). The most common apical constriction shapes were oval (55.9%) and round (35.3%). The mean distance between the apical constriction and the anatomical tip of the root was 0.61 mm, and 84.3% (86/102) were within 1 mm. Conclusion: The most common shape of an apical constriction was oval or round, and the distance to the apex was mostly within 1 mm, indicating that root canal therapy should stop 1 mm from the radiographic apex.

  9. Disrupted dynamics of F-actin and insulin granule fusion in INS-1 832/13 beta-cells exposed to glucotoxicity: partial restoration by glucagon-like peptide 1.

    Science.gov (United States)

    Quinault, Aurore; Gausseres, Blandine; Bailbe, Danielle; Chebbah, Nella; Portha, Bernard; Movassat, Jamileh; Tourrel-Cuzin, Cecile

    2016-08-01

    Actin dynamics in pancreatic β-cells is involved in insulin exocytosis but the molecular mechanisms of this dynamics and its role in biphasic insulin secretion in pancreatic β-cells is largely unknown. Moreover, the impact of a glucotoxic environment on the sub-cortical actin network dynamics is poorly studied. In this study, we investigate the behavior of insulin granules and the subcortical actin network dynamics in INS-1 832/13 β-cells submitted to a normal or glucotoxic environment. Our results show that glucose stimulation leads to a reorganization of the subcortical actin network with a rupture of its interactions with t-SNARE proteins (Syntaxin 1A and SNAP-25), promoting insulin secretion in INS-1 832/13 β-cells. Prolonged exposure of INS-1 832/13 β-cells to high-glucose levels (glucotoxicity) leads to the densification of the cortical actin network, which prevents its reorganization under acute glucose, and diminishes the glucose-stimulated insulin secretion, as shown by the decreased number of fusion events. The most interesting in our results is the partial restoration by GLP-1 of the insulin secretion ability from high-glucose treated INS-1 832/13 cells. This improved insulin exocytosis is associated with partial restored actin dynamics and fusion events during the two phases of the secretion, with a preferential involvement of Epac2 signaling in the first phase and a rather involvement of PKA signaling in the second phase of insulin exocytosis. All these data provide some new insights into the mechanism by which current therapeutics may be improving insulin secretion.

  10. Bony change of apical lesion healing process using fractal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Min; Park, Hyok; Jeong, Ho Gul; Kim, Kee Deog; Park, Chang Seo [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2005-06-15

    To investigate the change of bone healing process after endodontic treatment of the tooth with an apical lesion by fractal analysis. Radiographic images of 35 teeth from 33 patients taken on first diagnosis, 6 months, and 1 year after endodontic treatment were selected. Radiographic images were taken by JUPITER computerized Dental X-ray System. Fractal dimensions were calculated three times at each area by Scion Image PC program. Rectangular region of interest (30 x 30) were selected at apical lesion and normal apex of each image. The fractal dimension at apical lesion of first diagnosis (L{sub 0}) is 0.940 {+-} 0.361 and that of normal area (N{sub 0}) is 1.186 {+-} 0.727 (p<0.05). Fractal dimension at apical lesion of 6 months after endodontic treatment (L{sub 1}) is 1.076 {+-} 0.069 and that of normal area (N{sub 1}) is 1.192 {+-} 0.055 (p<0.05). Fractal dimension at apical lesion of 1 year after endodontic treatment (L{sub 2}) is 1.163 {+-} 0.074 and that of normal area (N{sub 2}) is 1.225 {+-} 0.079 (p<0.05). After endodontic treatment, the fractal dimensions at each apical lesions depending on time showed statistically significant difference. And there are statistically significant different between normal area and apical lesion on first diagnosis, 6 months after, 1 year after. But the differences were grow smaller as time flows. The evaluation of the prognosis after the endodontic treatment of the apical lesion was estimated by bone regeneration in apical region. Fractal analysis was attempted to overcome the limit of subjective reading, and as a result the change of the bone during the healing process was able to be detected objectively and quantitatively.

  11. 葡萄糖转运蛋白4及其下游信号分子在高糖刺激下肾小球系膜细胞中的作用%Effects of high glucose and insulin on expression of glucose transporter 4, Cbl-associated protein and cytoskeleton protein F-actin in rat glomerular mesangial cells in vitro

    Institute of Scientific and Technical Information of China (English)

    杜新; 黄颂敏; 唐万欣; 柳飞; 赖学莉

    2009-01-01

    )GLUT4、CAP和F-actin是糖尿病肾病发生发展的重要影响因子之一.%Objective To investigate the effects of high glucose and insulin on the expression of glucose transporter 4 (GLUT4), Cbl-associated protein (CAP) and cytoskeleton protein F-actin of glomerular mesangial cells (GMCs), in order to explore the function of GLUT4, Cbl-associated protein and F-actin in the pathogenesis and development of diabetic nephropathy (DN). Methods Cultured 1097 rat glomerular mesangial cells were divided into 8 groups: control, 10-9 mol/L insulin, 10-8 mol/L insulin, 10-6 mol/L insulin, high glucose (30 mmol/L), mannitol (25 mmol/L mannitol+5 mmol/L glucose), high glucose plus 10-6 mol/L insulin, high glucose plus 10-9 mol/L insulin. Expression of CAP mRNA and GLUT4 was measured by RT-PCR and immunohistochemistry method. F-actin was stained by rhodamine-pholloidin and the fluorescent intensity was calculated by image analysis system. Results The expression of GLUT4 mRNA and protein, CAP mRNA was found in normal giomerular mesangial cells (control), and there was no significant difference in 10-9 mol/L insulin group. The expression of GLUT4 mRNA (P<0.05) and protein (P<0.01), CAP mRNA (P<0.01) level was decreased in high glucose group compared with that of control group, but there was no significant difference in mannitol group. The expression of GLUT4 and CAP mRNA up-regulated with the increase of concentration of insulin. The expressions of GLUT4 mRNA in 10-8 mol/L insulin and 10-6 mol/L insulin groups were 2.06-fold and 2.66-fold of 10-9 mol/L insulin group, of GLUT4 protein were 1.93-fold and 2.83-fold of control, and of CAP mRNA were 1.91-fold and 2.15-fold of control, respectively. The expressions of GLUT4 mRNA, GLUT4 protein, CAP mRNA in high glucose plus insulin group were 2.15-fold, 2.08-fold, 2.14-fold of high glucose group respectively. High glucose decreased the fluorescent intensity of F-actin to 44.5% (P<0.01). 10-8 mol/L insulin and 10-6 mol/L insulin groups

  12. Dynein regulates epithelial polarity and the apical localization of stardust A mRNA.

    Science.gov (United States)

    Horne-Badovinac, Sally; Bilder, David

    2008-01-01

    Intense investigation has identified an elaborate protein network controlling epithelial polarity. Although precise subcellular targeting of apical and basolateral determinants is required for epithelial architecture, little is known about how the individual determinant proteins become localized within the cell. Through a genetic screen for epithelial defects in the Drosophila follicle cells, we have found that the cytoplasmic Dynein motor is an essential regulator of apico-basal polarity. Our data suggest that Dynein acts through the cytoplasmic scaffolding protein Stardust (Sdt) to localize the transmembrane protein Crumbs, in part through the apical targeting of specific sdt mRNA isoforms. We have mapped the sdt mRNA localization signal to an alternatively spliced coding exon. Intriguingly, the presence or absence of this exon corresponds to a developmental switch in sdt mRNA localization in which apical transcripts are only found during early stages of epithelial development, while unlocalized transcripts predominate in mature epithelia. This work represents the first demonstration that Dynein is required for epithelial polarity and suggests that mRNA localization may have a functional role in the regulation of apico-basal organization. Moreover, we introduce a unique mechanism in which alternative splicing of a coding exon is used to control mRNA localization during development.

  13. Dynein regulates epithelial polarity and the apical localization of stardust A mRNA.

    Directory of Open Access Journals (Sweden)

    Sally Horne-Badovinac

    2008-01-01

    Full Text Available Intense investigation has identified an elaborate protein network controlling epithelial polarity. Although precise subcellular targeting of apical and basolateral determinants is required for epithelial architecture, little is known about how the individual determinant proteins become localized within the cell. Through a genetic screen for epithelial defects in the Drosophila follicle cells, we have found that the cytoplasmic Dynein motor is an essential regulator of apico-basal polarity. Our data suggest that Dynein acts through the cytoplasmic scaffolding protein Stardust (Sdt to localize the transmembrane protein Crumbs, in part through the apical targeting of specific sdt mRNA isoforms. We have mapped the sdt mRNA localization signal to an alternatively spliced coding exon. Intriguingly, the presence or absence of this exon corresponds to a developmental switch in sdt mRNA localization in which apical transcripts are only found during early stages of epithelial development, while unlocalized transcripts predominate in mature epithelia. This work represents the first demonstration that Dynein is required for epithelial polarity and suggests that mRNA localization may have a functional role in the regulation of apico-basal organization. Moreover, we introduce a unique mechanism in which alternative splicing of a coding exon is used to control mRNA localization during development.

  14. Development of apical blebbing in the boar epididymis.

    Directory of Open Access Journals (Sweden)

    Jennifer Hughes

    Full Text Available Microvesicles are of increasing interest in biology as part of normal function of numerous systems; from the immune system (T cell activation to implantation of the embryo (invasion of the trophoblasts and sperm maturation (protein transfer in the epididymis. Yet, the mechanisms involved in the appearance of apical blebbing from healthy cells as part of their normal function remain understudied. Microvesicles are produced via one of two pathways: exocytosis or apical blebbing also termed ectocytosis. This work quantifies the histological appearance of apical blebbing in the porcine epididymis during development and examines the role of endogenous estrogens in regulating this blebbing. Apical blebbing appears at puberty and increases in a linear manner into sexual maturity suggesting that this blebbing is a mature phenotype. Endogenous estrogen levels were reduced with an aromatase inhibitor but such a reduction did not affect apical blebbing in treated animals compared with their vehicle-treated littermates. Epididymal production of apical blebs is a secretion mechanism of functionally mature principal cells regulated by factors other than estradiol.

  15. Haemostatic agents in apical surgery. A systematic review

    Science.gov (United States)

    Clé-Ovejero, Adrià

    2016-01-01

    Background Blood presence in apical surgery can prevent the correct vision of the surgical field, change the physical properties of filling materials and reduce their sealing ability. Objetive To describe which are the most effective and safest haemostatic agents to control bleeding in patients undergoing apical surgery. Material and Methods TWe carried out a systematic review, using Medline and Cochrane Library databases, of human clinical studies published in the last 10 years. Results The agents that proved more effective in bleeding control were calcium sulphate (100%) and collagen plus epinephrine (92.9%) followed by ferric sulphate (60%), gauze packing (30%) and collagen (16.7%). When using aluminium chloride (Expasyl®), over 90% of the apical lesions improved, but this agent seemed to increase swelling. Epinephrine with collagen did not significantly raise either blood pressure or heart rate. Conclusions Despite the use of several haemostatic materials in apical surgery, there is little evidence on their effectiveness and safety. The most effective haemostatic agents were calcium sulphate and epinephrine plus collagen. Epinephrine plus collagen did not seem to significantly raise blood pressure or heart rate during surgery. Aluminium chloride did not increase postoperative pain but could slightly increase postoperative swelling. Randomized clinical trials are needed to assess the haemostatic effectiveness and adverse effects of haemostatic materials in apical surgery. Key words:Haemostasis, apical surgery. PMID:27475689

  16. Changes of the Unique Odontogenic Properties of Rat Apical Bud Cells under the Developing Apical Complex Microenvironment

    Institute of Scientific and Technical Information of China (English)

    Jun Fang; Liang Tang; Xiao-hui Liu; Ling-ying Wen; Yan Jin

    2009-01-01

    Aim To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells (ABCs) in different microenvironment. Methodology Incisor apical bud tissues from neonatal SD rat were dissected and transplanted into the renal capsules to determine their odontogenic capability. Meanwhile ABCs were cultured and purified by repeated differential trypsinization. Then ABCs were cultured with conditioned medium from developing apical complex cells (DAC-CM). Immunocytochemistry, reverse transcriptase polymerase chain reaction (RT-PCR) and scanning electron microscope (SEM) were performed to compare the biological change of ABC treated with or without DAC-CM. Results First we confirmed the ability of apical bud to form crown-like structure ectopically. Equally important, by using the developing apical complex (DAC) conditioned medium, we found the microenvironment created by root could abrogate the "crown" features of ABCs and promote their proliferation and differentiation. Conclusion ABCs possess odontogenic capability to form crown-like tissues and this property can be affected by root-produced microenvironment.

  17. Differentiation of Apical Bud Cells in a Newly Developed Apical Bud Transplantation Model Using GFP Transgenic Mice as Donor

    Science.gov (United States)

    Sakagami, Ryuji; Yoshinaga, Yasunori; Okamura, Kazuhiko

    2016-01-01

    Rodent mandibular incisors have a unique anatomical structure that allows teeth to grow throughout the lifetime of the rodent. This report presents a novel transplantation technique for studying the apical bud differentiation of rodent mandibular incisors. Incisal apical end tissue with green fluorescent protein from transgenic mouse was transplanted to wild type mice, and the development of the transplanted cells were immunohistologically observed for 12 weeks after the transplantation. Results indicate that the green fluorescent apical end tissue replaced the original tissue, and cells from the apical bud differentiated and extended toward the incisal edge direction. The immunostaining with podoplanin also showed that the characteristics of the green fluorescent tissue were identical to those of the original. The green fluorescent cells were only found in the labial side of the incisor up to 4 weeks. After 12 weeks, however, they were also found in the lingual side. Here the green fluorescent cementocyte-like cells were only present in the cementum close to the dentin surface. This study suggests that some of the cells that form the cellular cementum come from the apical tissue including the apical bud in rodent incisors. PMID:26978064

  18. Differentiation of Apical Bud Cells in a Newly Developed Apical Bud Transplantation Model Using GFP Transgenic Mice as Donor.

    Directory of Open Access Journals (Sweden)

    Naoki Maruo

    Full Text Available Rodent mandibular incisors have a unique anatomical structure that allows teeth to grow throughout the lifetime of the rodent. This report presents a novel transplantation technique for studying the apical bud differentiation of rodent mandibular incisors. Incisal apical end tissue with green fluorescent protein from transgenic mouse was transplanted to wild type mice, and the development of the transplanted cells were immunohistologically observed for 12 weeks after the transplantation. Results indicate that the green fluorescent apical end tissue replaced the original tissue, and cells from the apical bud differentiated and extended toward the incisal edge direction. The immunostaining with podoplanin also showed that the characteristics of the green fluorescent tissue were identical to those of the original. The green fluorescent cells were only found in the labial side of the incisor up to 4 weeks. After 12 weeks, however, they were also found in the lingual side. Here the green fluorescent cementocyte-like cells were only present in the cementum close to the dentin surface. This study suggests that some of the cells that form the cellular cementum come from the apical tissue including the apical bud in rodent incisors.

  19. Effect of apical clearing technique on the treatment outcome of teeth with asymptomatic apical periodontitis: A randomized clinical trial

    Science.gov (United States)

    Mittal, Priya; Logani, Ajay; Shah, Naseem; Pandey, R. M.

    2016-01-01

    Aim: This study aims to compare the periapical healing of teeth with asymptomatic apical periodontitis treated either by conventional apical preparation (CAP) or apical clearing technique (ACT). Materials and Methods: Twenty subjects with bilateral nonvital similar teeth exhibiting comparable periapical index (PAI) score were enrolled and randomly allocated. Group I (CAP, n = 20): Apical preparation three sizes greater (master apical file [MAF]) than the first binding file at the established working length. Group II (ACT, n = 20): Apical preparation three sizes greater than the MAF that was followed by dry reaming. Root canal therapy was accomplished in single-visit for all the teeth. They were pursued radiographically at 3, 6, 9 and 12 months. Pre- and post-treatment PAI scores were compared. To ascertain the proportion of healed teeth between the two groups, McNemar Chi-square test was applied. Results: At 3, 6, and 9 months’ time interval the proportion of healed teeth for Group II (ACT) was greater in comparison to Group I (CAP) (P < 0.05). However, at 12 months follow-up period this difference was not significant (P = 0.08). Conclusion: ACT enhanced the healing kinetics. However, the long-term (12 months) radiographic outcome was similar for either technique. PMID:27656054

  20. Five-year longitudinal assessment of the prognosis of apical microsurgery

    DEFF Research Database (Denmark)

    von Arx, Thomas; Jensen, Simon S; Hänni, Stefan

    2012-01-01

    Apical surgery is an important treatment option for teeth with post-treatment apical periodontitis. Knowledge of the long-term prognosis is necessary when weighing apical surgery against alternative treatments. This study assessed the 5-year outcome of apical surgery and its predictors in a cohor...

  1. Apical Revascularization after Delayed Tooth Replantation: An Unusual Case

    Science.gov (United States)

    Nelson-Filho, Paulo; Silva, Lea Assed Bezerra; Silva, Raquel Assed Bezerra; de Carvalho, Fabricio Kitazono; de Queiroz, Alexandra Mussolino

    2016-01-01

    The aim of this paper is to present the clinical and radiological outcome of the treatment involving a delayed tooth replantation after an avulsed immature permanent incisor, with a follow-up of 1 year and 6 months. An 8-year-old boy was referred after dental trauma that occurred on the previous day. The permanent maxillary right central incisor (tooth 11) had been avulsed. The tooth was hand-held during endodontic therapy and an intracanal medication application with calcium hydroxide-based paste was performed. An apical plug with mineral trioxide aggregate (MTA) was introduced into the apical portion of the canal. When the avulsed tooth was replanted with digital pressure, a blood clot had formed within the socket, which moved the MTA apical plug about 2 mm inside of the root canal. These procedures developed apical revascularization, which promoted a successful endodontic outcome, evidenced by apical closure, slight increase in root length, and absence of signs of external root resorption, during a follow-up of 1 year and 6 months. PMID:27882250

  2. [Mineral trioxide aggregate (MTA) a success story in apical surgery].

    Science.gov (United States)

    von Arx, Thomas

    2016-01-01

    The objective of apical surgery is to retain teeth with persistent apical pathosis following orthograde root canal treatment if endodontic non-surgical revision is difficult or associated with risks, or is even declined by the patient. Since the most frequent cause of recurrent apical disease is bacterial reinfection from the (remaining) root canal system, the bacteria-tight root-end filling is the most important step in apical surgery. In the early 1990s, mineral trioxide aggregate (MTA) was developed at the Loma Linda University in California/USA. Preclinical studies clearly showed that MTA has a high sealing capability, a good material stability and an excellent biocompatbility. Multiple experimental studies in animals highlighted the mild tissue reactions observed adjacent to this material. Furthermore, histological analysis of the periapical regions demonstrated a frequent deposition of new cementum not only onto the resection plane (cut dentinal surface), but also directly onto MTA. For these reasons, MTA is considered a bioactive material. In 1997 MTA was cleared for clinical use in patients. Multiple prospective clinical and randomized studies have documented high and constant success rates of MTA-treated teeth in apical surgery. A recently published longitudinal study showed that MTA-treated teeth remained stable over five years; hence the high healed rates documented after one year are maintained during long-term observation.

  3. Apical Revascularization after Delayed Tooth Replantation: An Unusual Case

    Directory of Open Access Journals (Sweden)

    Marília Pacífico Lucisano

    2016-01-01

    Full Text Available The aim of this paper is to present the clinical and radiological outcome of the treatment involving a delayed tooth replantation after an avulsed immature permanent incisor, with a follow-up of 1 year and 6 months. An 8-year-old boy was referred after dental trauma that occurred on the previous day. The permanent maxillary right central incisor (tooth 11 had been avulsed. The tooth was hand-held during endodontic therapy and an intracanal medication application with calcium hydroxide-based paste was performed. An apical plug with mineral trioxide aggregate (MTA was introduced into the apical portion of the canal. When the avulsed tooth was replanted with digital pressure, a blood clot had formed within the socket, which moved the MTA apical plug about 2 mm inside of the root canal. These procedures developed apical revascularization, which promoted a successful endodontic outcome, evidenced by apical closure, slight increase in root length, and absence of signs of external root resorption, during a follow-up of 1 year and 6 months.

  4. Cryopreservation of Pelargonium apices by droplet-vitrification.

    Science.gov (United States)

    Gallard, Anthony; Panis, Bart; Dorion, Nöelle; Swennen, Rony; Grapin, Agnès

    2008-01-01

    The droplet-vitrification method was adapted to Pelargonium apices by optimizing the duration of the loading solution (LS) as well as the plant vitrification solution 2 (PVS2). The excised apices were dehydrated in two steps (20 min in LS and 15 min in PVS2) and then immersed directly in liquid nitrogen (LN). After thawing and unloading in the recovery solution at room temperature for 15 min, apices were plated onto semi-solid Murashige and Skoog medium. This simple protocol without any pretreatment was successfully applied to eight cultivars with a survival level ranging between 55.6 - 96.2 percent and a regrowth level between 9.1 and 70.6 percent. These results prove the feasibility of the long-term storage of Pelargonium germplasm through cryopreservation.

  5. Helical twist controls the thickness of F-actin bundles

    NARCIS (Netherlands)

    Claessens, M.M.A.E.; Semmrich, C.; Ramos, L.; Bausch, A.R.

    2008-01-01

    In the presence of condensing agents such as nonadsorbing polymer, multivalent counter ions, and specific bundling proteins, chiral biopolymers typically form bundles with a finite thickness, rather than phase-separating into a polymer-rich phase. Although short-range repulsive interactions or geome

  6. Mical links semaphorins to F-actin disassembly

    NARCIS (Netherlands)

    Hung, R.J.; Yazdani, U.; Yoon, J.; Wu, H.; Yang, T.; Gupta, N.; Huang, Z.; Berkel, van W.J.H.; Terman, J.R.

    2010-01-01

    How instructive cues present on the cell surface have their precise effects on the actin cytoskeleton is poorly understood. Semaphorins are one of the largest families of these instructive cues and are widely studied for their effects on cell movement, navigation, angiogenesis, immunology and cancer

  7. [Nonsurgical retreatment in a case of a radiolucent apical lesion].

    Science.gov (United States)

    Vicente Gómez, A; Rodríguez Ponce, A

    1989-01-01

    We present a case of failure that was helpful solved without surgical endodontic treatment. We don't achieve clinical success besides endodontic treatment was twice remade. Finally we decided to put a temporary filling with calcium hydroxide and wait until apical radiolucency disappear and complete our treatment with gutta-percha, sealer and lateral condensation.

  8. Apical vault repair, the cornerstone or pelvic vault reconstruction.

    Science.gov (United States)

    Ross, J W

    1997-01-01

    Pelvic organ prolapse remains a difficult problem for pelvic reconstructive surgery. Before new surgical procedures can be developed a good understanding of pelvic anatomy is necessary. It is widely held that the etiology of pelvic organ prolapse is secondary to stretch neuropathy following childbirth and chronic cough or constipation. Several transvaginal and transabdominal procedures have been developed over the years. With the increasing use of laparoscopy, a new variation on existing culdeplasty techniques has been developed. Following anatomical principles, the apical vault repair reestablishes the pericervical ring at the vaginal apex. The incorporation of pubocervical fascia, uterosacral-cardinal ligament and the rectovaginal fascia provides a strong anchor for the vaginal apex. In addition, the repair should help prevent future transverse cystocele, rectocele, enterocele and apical vault prolapse. Early outcome studies suggest that the apical vault repair should be used routinely with laparoscopic urethropexy, laparoscopic hysterectomy and the repair of pelvic organ prolapse. Good apical vault support is considered the cornerstone of pelvic reconstruction.

  9. The apical plasma membrane of chitin-synthesizing epithelia

    Institute of Scientific and Technical Information of China (English)

    Bernard Moussian

    2013-01-01

    Chitin is the second most abundant polysaccharide on earth.It is produced at the apical side of epidermal,tracheal,fore-,and hindgut epithelial cells in insects as a central component of the protective and supporting extracellular cuticle.Chitin is also an important constituent of the midgut peritrophic matrix that encases the food supporting its digestion and protects the epithelium against invasion by possibly ingested pathogens.The enzyme producing chitin is a glycosyltransferase that resides in the apical plasma membrane forming a pore to extrude the chains of chitin into the extracellular space.The apical plasma membrane is not only a platform for chitin synthases but,probably through its shape and equipment with distinct factors,also plays an important role in orienting and organizing chitin fibers.Here,I review findings on the cellular and molecular constitution of the apical plasma membrane of chitin-producing epithelia mainly focusing on work done in the fruit fly Drosophila melanogaster.

  10. Apical root resorption after orthodontic treatment -- a retrospective study.

    Science.gov (United States)

    Apajalahti, Satu; Peltola, Jaakko Sakari

    2007-08-01

    The purpose of the study was to compare the incidence and severity of apical root resorption in patients treated with different orthodontic appliances and to evaluate the effect of treatment duration on the degree of apical root resorption. A further aim was to analyse the degree of apical root resorption in different tooth groups in patients presenting with root resorption. The sample consisted of 625 patients (269 males, 356 females) aged 8-16 years at the beginning of treatment. Active removable plates and fixed appliances were used most frequently. Following exclusion of poor quality radiographs, the final sample included 601 patients (348 females, 253 males). Root resorption in all tooth groups, except third molars, was evaluated from pre- and post-treatment panoramic radiographs. The correlation of root resorption with treatment modality and duration was studied using multinomial logistic regression analysis. Of the tooth groups, maxillary incisors showed apical root resorption most frequently, followed by the mandibular incisors. Root resorption was significantly correlated with fixed appliance treatment (P resorption. The mean duration of treatment in patients without root resorption was 1.5 years, whereas in those with severe resorption was 2.3 years. The most severe resorption was seen in the maxillary incisors and premolars. It is concluded that with a long duration of fixed appliance treatment, the risk of severe resorption increases. In patients where treatment is prolonged, a 6-month radiographic follow-up is recommended.

  11. Assessment of apical periodontitis by MRI. A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Geibel, M.A. [Ulm Univ. (Germany). Oral and Maxillofacial Surgery; Schreiber, E.S.; Bracher, A.K.; Rasche, V. [Ulm Univ. (Germany). Internal Medicine II; Hell, E.; Ulrici, J. [Sirona Dental Systems GmbH, Bensheim (Germany). Dental Imaging; Sailer, L.K. [DOC Praxisklinik im Wiley, Neu-Ulm (Germany). MKG; Ozpeynirci, Y. [Ulm Univ. (Germany). Diagnostic and Interventional Radiology

    2015-04-15

    The purpose of this clinical feasibility study was to evaluate the applicability of magnetic resonance imaging (MRI) for the assessment of apical periodontitis in direct comparison with cone beam CT (CBCT). 19 consecutive patients (average age 43 ± 13 years) with 34 lesions in total (13 molars, 14 premolars and 7 front teeth) were enrolled in this feasibility study. Periapical lesions were defined as periapical radiolucencies (CBCT) or structural changes in the spongy bone signal (MRI), which were connected with the apical part of a root and with at least twice the width of the periodontal ligament space. The location and dimension of the lesions were compared between MRI and CBCT. While mainly mineralized tissue components such as teeth and bone were visible with CBCT, complimentary information of the soft tissue components was assessable with MRI. The MRI images provided sufficient diagnostic detail for the assessment of the main structures of interest. Heterogeneous contrast was observed within the lesion, with often a clear enhancement close to the apical foramen and the periodontal gap. No difference for lesion visibility was observed between MRI and CBCT. The lesion dimensions corresponded well, but were slightly but significantly overestimated with MRI. A heterogeneous lesion appearance was observed in several patients. Four patients presented with a well circumscribed hyperintense signal in the vicinity of the apical foramen. The MRI capability of soft tissue characterization may facilitate detailed analysis of periapical lesions. This clinical study confirms the applicability of multi-contrast MRI for the identification of periapical lesions.

  12. Hypertrophic cardiomyopathy with apical left ventricular aneurysm: a case report

    Institute of Scientific and Technical Information of China (English)

    江腾勇; 韩智红; 王京; 吕强; 吴学思

    2002-01-01

    @@ Morphological diversity is one characteristic of hypertrophic cardi omyopathy (HCM), but it is not common that HCM is associated with apical left ve ntricular aneurysm (LVA) without evidence of a coronary artery lesion. We repor t on such a case and review the pathogenesis, manifestations and diagnostic meth ods by collecting the few available papers published on this topic.

  13. A survey of small RNA population during FR-induced apical hook opening

    Directory of Open Access Journals (Sweden)

    Ying eLi

    2014-04-01

    Full Text Available Photomorphogenesis is a mechanism employed by plants to regulate their architecture and developmental program in response to light conditions. As they emerge into light for the first time, dark-grown seedlings employ a rapid and finely-controlled photomorphogenic signaling network. Small RNAs have increasingly been revealed to play an important role in regulating multiple aspects of plant development, by modulating the stability of mRNAs. The rapid alteration of the mRNA transcriptome is a known hallmark of the de-etiolation response, thus we investigated the small RNA transcriptome during this process in specific seedling tissues. Here we describe a survey of the small RNA expression profile in four tissues of etiolated soybean seedlings, the cotyledons, hypocotyl and the convex and concave sides of the apical hook. We also investigate how this profile responds to a one-hour far-red light treatment. Our data suggests that miRNAs show a different global profile between these tissues and treatments, suggesting a possible role for tissue- and treatment-specific expression in the differential morphology of the seedling on de-etiolation. Further evidence for the role of miRNA in light-regulated development is given by the de-etiolation responses of a hypomorphic ago1 mutant, which displays reduced and delayed photomorphogenic responses in apical hook and cotyledon angle to far-red light.

  14. Competing dynamic phases of active polymer networks

    Science.gov (United States)

    Freedman, Simon; Banerjee, Shiladitya; Dinner, Aaron R.

    Recent experiments on in-vitro reconstituted assemblies of F-actin, myosin-II motors, and cross-linking proteins show that tuning local network properties can changes the fundamental biomechanical behavior of the system. For example, by varying cross-linker density and actin bundle rigidity, one can switch between contractile networks useful for reshaping cells, polarity sorted networks ideal for directed molecular transport, and frustrated networks with robust structural properties. To efficiently investigate the dynamic phases of actomyosin networks, we developed a coarse grained non-equilibrium molecular dynamics simulation of model semiflexible filaments, molecular motors, and cross-linkers with phenomenologically defined interactions. The simulation's accuracy was verified by benchmarking the mechanical properties of its individual components and collective behavior against experimental results at the molecular and network scales. By adjusting the model's parameters, we can reproduce the qualitative phases observed in experiment and predict the protein characteristics where phase crossovers could occur in collective network dynamics. Our model provides a framework for understanding cells' multiple uses of actomyosin networks and their applicability in materials research. Supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

  15. Implantation of a left ventricular assist device in patients with a complex apical anatomy.

    Science.gov (United States)

    Palmen, Meindert; Verwey, Harriette F; Haeck, Marlieke L A; Holman, Eduard R; Schalij, Martin J; Klautz, Robert J M

    2012-12-01

    Implantation of a left ventricular assist device can be challenging in patients with an altered apical anatomy after cardiac surgery or as the result of the presence of a calcified apical aneurysm. In this paper we present 2 cases with a challenging apical anatomy and introduce a new surgical technique facilitating left ventricular assist device implantation in these patients.

  16. Through-flow of water in leaves of a submerged plant is influenced by the apical opening

    DEFF Research Database (Denmark)

    Pedersen, Ole; Jørgensen, Lise Bolt; Sand-Jensen, Kaj

    1997-01-01

    Submerged plant, apical opening, hydathode, Sparganium, hydraulic architecture, leaf specific conductivity......Submerged plant, apical opening, hydathode, Sparganium, hydraulic architecture, leaf specific conductivity...

  17. Apical ballooning-like syndrome: Hypocalcemia? What else!

    Directory of Open Access Journals (Sweden)

    Maria Accadia

    2016-01-01

    Full Text Available Apical ballooning syndrome (ABS, also known as Takotsubo or stress cardiomyopathy, is characterised by acute, transient and severe LV dysfunction, mimicking myocardial infarction; it occurs, in most cases, in the absence of obstructive coronary disease and is precipitated by severe emotional or physical stress, but many other potential triggers has been identi ed in the last years. Although the pathogenesis of ABS remains unclear, the most common mechanisms suggested are coronary vasospam and an exaggerated sympathetic activation associated to high levels of plasma cathecolamine leading to cardiotoxicity.We describe two cases of Apical Ballooning like Syndrome that were triggered by severe, acute hypocalcemia, without evidence of coronary vasospasm and with normal hematic level of cathecolamines.

  18. Aseptic multiplication of banana from excised floral apices.

    Science.gov (United States)

    Cronauer, S S; Krikorian, A D

    1985-08-01

    Most economically important bananas and plantains are large triploid seedless herbs that must be propagated vegetatively by removing small side shoots or "suckers" from the parent plant or by planting seed pieces of larger corms. Consequently, multiplication of stock material is time consuming, Recently, the rapid production of young banana plantlets suitable for use as "seed" material has been described. Vegetative shoot apices were isolated and multiplied using aseptic tissue culture techniques. Although these multiplication systems, once established, can produce thousands of plants in a relatively short period of time, their establishment necessitates the initial sacrifice of an individual specimen, which may not always be desirable or prudent should a limited parent stock be available. We describe here the production and multiplication of rooted banana plantlets from the isolation and culture of terminal floral apices.

  19. The Effect of Canal Contamination with Saliva on Apical Sealing

    Directory of Open Access Journals (Sweden)

    S Sabaghi

    2014-08-01

    Methods: In this laboratory study, 58 human uni-root teeth were cleaned and shaped for obturation with gutta percha and sealer AH26. In the case group, specimens were contaminated with human saliva immediately before obturation, whereas the teeth in the control group were kept dry. All canals were filled by lateral condensation technique. Moreover, the teeth were placed in methylene blue dye for 3 days. Dye penetration was measured using a stereomicrosope. As a matter of fact, the study data were analyzed via utilizing t-test. Results: A significant difference was found between the two groups in regard with the apical leakage(P<0.001. The microleakage mean of dye in the dry group was 3/48mm, whereas it was 6/36mm in the saliva contaminated group. Conclusion: The study findings revealed that complete drying of canal can improve apical sealing.

  20. Transient apical dyskinesia with a pacemaker: Electrocardiographic features.

    Science.gov (United States)

    Núñez-Gil, Iván J; Feltes, Gisela I; Mejía-Rentería, Hernán D; Biagioni, Corina; De Agustín, J Alberto; Vivas, David; Fernández-Ortiz, Antonio

    2015-04-01

    Transient apical dyskinesia syndromes present features similar to acute coronary syndromes, but with normal coronary arteries and rapid complete resolution of wall motion alterations. We report the case of a 73-year-old woman who was admitted to hospital because of typical chest pain at rest after her brother's death. She had had a pacemaker implanted in 2001. Troponin levels were elevated and apical hypokinesia was shown by ventriculography and echocardiography, with normal coronary arteries. Evolving ECG alterations were observed in spite of the continued pacing rhythm. All these alterations were fully resolved after discharge. This case shows that, even in the presence of a pacemaker, evolving ECG alterations can be observed in Takotsubo syndrome.

  1. Apical versus Basal Neurogenesis Directs Cortical Interneuron Subclass Fate

    Directory of Open Access Journals (Sweden)

    Timothy J. Petros

    2015-11-01

    Full Text Available Fate determination in the mammalian telencephalon, with its diversity of neuronal subtypes and relevance to neuropsychiatric disease, remains a critical area of study in neuroscience. Most studies investigating this topic focus on the diversity of neural progenitors within spatial and temporal domains along the lateral ventricles. Often overlooked is whether the location of neurogenesis within a fate-restricted domain is associated with, or instructive for, distinct neuronal fates. Here, we use in vivo fate mapping and the manipulation of neurogenic location to demonstrate that apical versus basal neurogenesis influences the fate determination of major subgroups of cortical interneurons derived from the subcortical telencephalon. Somatostatin-expressing interneurons arise mainly from apical divisions along the ventricular surface, whereas parvalbumin-expressing interneurons originate predominantly from basal divisions in the subventricular zone. As manipulations that shift neurogenic location alter interneuron subclass fate, these results add an additional dimension to the spatial-temporal determinants of neuronal fate determination.

  2. Apical ballooning-like syndrome: Hypocalcemia? What else!

    OpenAIRE

    Maria Accadia; Marianna Abitabile; Salvatore Rumolo; Scotto di Uccio Fortunato; Luigi Irace; Andrea Tuccillo; Giuseppe Mercogliano; Bernardino Tuccillo

    2016-01-01

    Apical ballooning syndrome (ABS), also known as Takotsubo or stress cardiomyopathy, is characterised by acute, transient and severe LV dysfunction, mimicking myocardial infarction; it occurs, in most cases, in the absence of obstructive coronary disease and is precipitated by severe emotional or physical stress, but many other potential triggers has been identi ed in the last years. Although the pathogenesis of ABS remains unclear, the most common mechanisms suggested are coronary vasospam an...

  3. The Effect of Canal Contamination with Saliva on Apical Sealing

    Directory of Open Access Journals (Sweden)

    S Sabaghi

    2014-08-01

    Full Text Available Introduction: Root canal obturation aims at sealing the root canal system to prevent re-contamination of canal and periapical space. Presence of moisture in canal before obturation may posit a negative effect on the quality of canal sealing. Therefore, this study was conducted to investigate the effect of canal contamination with saliva on apical microleakage. Methods: In this laboratory study, 58 human uni-root teeth were cleaned and shaped for obturation with gutta percha and sealer AH26. In the case group, specimens were contaminated with human saliva immediately before obturation, whereas the teeth in the control group were kept dry. All canals were filled by lateral condensation technique. Moreover, the teeth were placed in methylene blue dye for 3 days. Dye penetration was measured using a stereomicrosope. As a matter of fact, the study data were analyzed via utilizing t-test. Results: A significant difference was found between the two groups in regard with the apical leakage(P<0.001. The microleakage mean of dye in the dry group was 3/48mm, whereas it was 6/36mm in the saliva contaminated group. Conclusion: The study findings revealed that complete drying of canal can improve apical sealing.

  4. Apical Periodontitis - Is It Accountable for Cardiovascular Diseases?

    Science.gov (United States)

    Garg, Paridhi; Chaman, Chandrakar

    2016-08-01

    The aim of this review was to assess the relationship between apical periodontitis and cardiovascular diseases and the predictive factors regarding this association. Cross sectional and observational studies have been included, which are mostly retrospective. A comprehensive search was performed in the Systematic Electronic Databases, PUBMED and MEDLINE from 1919 till September 2014. Articles were also hand searched. From 86 studies identified, all were read and 58 articles which were relevant were included in the text. Some articles were excluded because they were pertaining to periodontology and other systemic disorders. Some were solely animal studies and were thus excluded. Our results suggest an independent association between cardiovascular diseases and apical periodontitis. A causal relationship could not be established since weak parameters of risk have been assessed in the studies, population taken is difficult to compare and other confounding factors have not been ruled out. Only a more focused and better instituted scientific research can determine this association. Establishing a cause and effect relationship between apical periodontitis and cardiovascular diseases can affect the course of treatment of cardiovascular diseases. It is not only of interest from the scientific point of view but also from public health perspective.

  5. Visualization of the network of primo vessels and primo nodes above the pia mater of the brain and spine of rats by using Alcian blue.

    Science.gov (United States)

    Lee, Ho-Sung; Lee, Byung-Cheon

    2012-10-01

    By spraying and injecting Alcian blue into the lateral ventricle, we were able to visualize the network of the nerve primo vascular system above the pia mater of the brain and spine of rats. Staining these novel structures above the pia mater with 4',6-diamidino-2-phenylindole demonstrated that they coexisted in cellular and extracellular DNA forms. The cellular primo node consisted of many cells surrounded by rod-shaped nuclei while the extracellular primo node had a different morphology from that of a general cell in terms of DNA signals, showing granular DNA in a threadlike network of extracellular DNA. Also, differently from F-actin in general cells, the F-actin in the primo vessel was short and rod-shaped. Light and transmission electron microscopic images of the PN showed that the nerve primo vascular system above the pia mater of the brain and spine was a novel dynamic network, suggesting the coexistence of DNA and extracellular DNA. Based on these data, we suggest that a novel dynamic system with a certain function exists above the pia mater of the central nerve system. We also discuss the potential of this novel network system in the brain and spine as related to acupuncture meridians and neural regeneration.

  6. Occurrence of the Transition of Apical Architecture and Expression Patterns of Related Genes during Conversion of Apical Meristem Identity in G2 Pea

    Institute of Scientific and Technical Information of China (English)

    Da-Yong Wang; Qing Li; Ke-Ming Cui; Yu-Xian Zhu

    2009-01-01

    G2 pea exhibits an apical senescence delaying phenotype under short-day (SD) conditions; however, the structural basis for its apical development is still largely unknown. In the present study, the apical meristem of SD-grown G2 pea plants underwent a transition from vegetative to indeterminate inflorescence meristem, but the apical meristem of long-day (LD)-grown G2 pea plants would be further converted to determinate floral meristem. Both SD signal and GA3 treatment enhanced expression of the putative calcium transporter PPF1, and pea homologs of TFL1 (LF and DET), whereas LD signal suppressed their expression at 60 d post-flowering compared with those at 40 d post-flowering. Both PPF1 and LF expressed at the vegetative and reproductive phases in SD-grown apical buds, but floral initiation obviously increased the expression level of PPF1 compared with the unchanged expression level of LF from 40 to 60 d post-flowering. In addition, although the floral initiation significantly enhanced the expression levels of PPF1 and DET, DET was mainly expressed after floral initiation in SD-grown apical buds. Therefore, the main structural difference between LD- and SD-grown apical meristem in G2 pea lies in whether their apical indeterminate inflorescence medstem could be converted to the determinate structure.

  7. SEM investigation of Er:YAG laser apical preparation

    Science.gov (United States)

    Bǎlǎbuc, Cosmin; Todea, Carmen; Locovei, Cosmin; RǎduÅ£ǎ, Aurel

    2016-03-01

    Endodontic surgery involves the incision and flap elevation, the access to the root tip, its resection, the cavity retrograde preparation and filling it with biocompatible material that provides a good seal of the apex[1]. Apicoectomy is compulsory in endodontic surgery. The final stage involves the root retropreparation and the carrying out of the retrograde obturation. In order to perform the retrograde preparation the endodontist can use various tools such as lowspeed conventional handpieces, sonic and ultrasonic equipment. The ideal depth of the preparation should be 3 mm, exceeding this value may affect the long-term success of the obturation [2]. Resection at the depth of 3 mm reduces apical ramifications by 98% and lateral root canals by 93%. The ultrasonic retropreparation has numerous advantages compared to the dental drill. Firstly, the cavity will be in the axis of the tooth which implies a minimum destruction of the root canal morphology. The preparations are precise, and the cutting pattern is perpendicular to the long axis of the root, the advantage being the reduction in the number of dentinal tubules exposed at the resected area [3]. Therefore, the retrograde filling is the procedure when an inert and non-toxic material is compacted in the apically created cavity.[4,5]. The Er:YAG laser is the most common wavelength indicated for dental hard tissue preparation. Its natural selectivity offers a significant advantage compared to the conventional hard tissue preparation [6-9].The purpose of this in vitro study was to investigate the quality of Er:YAG laser apical third preparation using Scanning Electron Microscopy (SEM), in comparison with the conventional ultrasonic method.

  8. Bacterial communities associated with apical periodontitis and dental implant failure

    Directory of Open Access Journals (Sweden)

    Simon Dingsdag

    2016-11-01

    Full Text Available Background: Previously, we demonstrated that bacteria reside in apparently healed alveolar bone, using culture and Sanger sequencing techniques. Bacteria in apparently healed alveolar bone may have a role in peri-implantitis and dental implant failure. Objective: To compare bacterial communities associated with apical periodontitis, those colonising a failed implant and alveolar bone with reference biofilm samples from healthy teeth. Methods and results: The study consisted of 196 samples collected from 40 patients undergoing routine dental implant insertion or rehabilitation. The bacterial 16S ribosomal DNA sequences were amplified. Samples yielding sufficient polymerase chain reaction product for further molecular analyses were subjected to terminal restriction fragment length polymorphism (T-RFLP; 31 samples and next generation DNA sequencing (454 GS FLX Titanium; 8 samples. T-RFLP analysis revealed that the bacterial communities in diseased tissues were more similar to each other (p<0.049 than those from the healthy reference samples. Next generation sequencing detected 13 bacterial phyla and 373 putative bacterial species, revealing an increased abundance of Gram-negative [Prevotella, Fusobacterium (p<0.004, Treponema, Veillonellaceae, TG5 (Synergistetes] bacteria and a decreased abundance of Gram-positive [(Actinomyces, Corynebacterium (p<0.008] bacteria in the diseased tissue samples (n=5 relative to reference supragingival healthy samples (n=3. Conclusion: Increased abundances of Prevotella, Fusobacterium and TG5 (Synergistetes were associated with apical periodontitis and a failed implant. A larger sample set is needed to confirm these trends and to better define the processes of bacterial pathogenesis in implant failure and apical periodontitis. The application of combined culture-based, microscopic and molecular technique-based approaches is suggested for future studies.

  9. Apical Na+ permeability of frog skin during serosal Cl- replacement.

    Science.gov (United States)

    Leibowich, S; DeLong, J; Civan, M M

    1988-05-01

    Gluconate substitution for serosal Cl- reduces the transepithelial short-circuit current (Isc) and depolarizes short-circuited frog skins. These effects could result either from inhibition of basolateral K+ conductance, or from two actions to inhibit both apical Na+ permeability (PapNa) and basolateral pump activity. We have addressed this question by studying whole-and split-thickness frog skins. Intracellular Na+ concentration (CcNa) and PapNa have been monitored by measuring the current-voltage relationship for apical Na+ entry. This analysis was conducted by applying trains of voltage pulses, with pulse durations of 16 to 32 msec. Estimates of PapNa and CcNa were not detectably dependent on pulse duration over the range 16 to 80 msec. Serosal Cl- replacement uniformly depolarized short-circuited tissues. The depolarization was associated with inhibition of Isc across each split skin, but only occasionally across the whole-thickness preparations. This difference may reflect the better ionic exchange between the bulk medium and the extracellular fluid in contact with the basolateral membranes, following removal of the underlying dermis in the split-skin preparations. PapNa was either unchanged or increased, and CcNa either unchanged or reduced after the anionic replacement. These data are incompatible with the concept that serosal Cl- replacement inhibits PapNa and Na,K-pump activity. Gluconate substitution likely reduces cell volume, triggering inhibition of the basolateral K+ channels, consistent with the data and conclusions of S.A. Lewis, A.G. Butt, M.J. Bowler, J.P. Leader and A.D.C. Macknight (J. Membrane Biol. 83:119-137, 1985) for toad bladder. The resulting depolarization reduces the electrical force favoring apical Na+ entry. The volume-conductance coupling serves to conserve volume by reducing K+ solute loss. Its molecular basis remains to be identified.

  10. Reparación apical y periapical post tratamiento endodontico.

    OpenAIRE

    Altare, Lia

    2010-01-01

    El propósito de este trabajo es describir el proceso reparativo apical y periapical post tratamiento endodóntico , los mecanismos y sistemas celulares involucrados ,dentro del campo de la Endodoncia Biomolecular.Una nueva era de conocimientos invaden a la Endodoncia Moderna dado por la Ingeniería Tisular Endodóntica desde donde se plantean alternativas terapéuticas .El análisis de la capacidad biológica reparativa de cada paciente demuestra una variabilidad en la respuesta frente a un tratami...

  11. Pulp revascularization of immature dog teeth with apical periodontitis.

    Science.gov (United States)

    Thibodeau, Blayne; Teixeira, Fabricio; Yamauchi, Mitsuo; Caplan, Daniel J; Trope, Martin

    2007-06-01

    This study examined the ability of a collagen solution to aid revascularization of necrotic-infected root canals in immature dog teeth. Sixty immature teeth from 6 dogs were infected, disinfected, and randomized into experimental groups: 1: no further treatment; 2: blood in canal; 3: collagen solution in canal, 4: collagen solution + blood, and 5: negative controls (left for natural development). Uncorrected chi-square analysis of radiographic results showed no statistical differences (p >or= 0.05) between experimental groups regarding healing of radiolucencies but a borderline statistical difference (p = 0.058) for group 1 versus group 4 for radicular thickening. Group 2 showed significantly more apical closure than group 1 (p = 0.03) and a borderline statistical difference (p = 0.051) for group 3 versus group 1. Uncorrected chi-square analysis revealed that there were no statistical differences between experimental groups for histological results. However, some roots in each of groups 1 to 4 (previously infected) showed positive histologic outcomes (thickened walls in 43.9%, apical closure in 54.9%, and new luminal tissue in 29.3%). Revascularization of disinfected immature dog root canal systems is possible.

  12. Fat1 interacts with Fat4 to regulate neural tube closure, neural progenitor proliferation and apical constriction during mouse brain development.

    Science.gov (United States)

    Badouel, Caroline; Zander, Mark A; Liscio, Nicole; Bagherie-Lachidan, Mazdak; Sopko, Richelle; Coyaud, Etienne; Raught, Brian; Miller, Freda D; McNeill, Helen

    2015-08-15

    Mammalian brain development requires coordination between neural precursor proliferation, differentiation and cellular organization to create the intricate neuronal networks of the adult brain. Here, we examined the role of the atypical cadherins Fat1 and Fat4 in this process. We show that mutation of Fat1 in mouse embryos causes defects in cranial neural tube closure, accompanied by an increase in the proliferation of cortical precursors and altered apical junctions, with perturbations in apical constriction and actin accumulation. Similarly, knockdown of Fat1 in cortical precursors by in utero electroporation leads to overproliferation of radial glial precursors. Fat1 interacts genetically with the related cadherin Fat4 to regulate these processes. Proteomic analysis reveals that Fat1 and Fat4 bind different sets of actin-regulating and junctional proteins. In vitro data suggest that Fat1 and Fat4 form cis-heterodimers, providing a mechanism for bringing together their diverse interactors. We propose a model in which Fat1 and Fat4 binding coordinates distinct pathways at apical junctions to regulate neural progenitor proliferation, neural tube closure and apical constriction.

  13. Apical localization of PMCA2w/b is enhanced in terminally polarized MDCK cells

    OpenAIRE

    Antalffy, Géza; Caride, Ariel J.; Pászty, Katalin; Hegedus, Luca; Padanyi, Rita; STREHLER, EMANUEL E.; Enyedi, Ágnes

    2011-01-01

    The “w” splice forms of PMCA2 localize to distinct membrane compartments such as the apical membrane of the lactating mammary epithelium, the stereocilia of inner ear hair cells or the post-synaptic density of hippocampal neurons. Previous studies indicated that PMCA2w/b was not fully targeted to the apical domain of MDCK cells but distributed more evenly to the lateral and apical membrane compartments. Overexpression of the apical scaffold protein NHERF2, however, greatly increased the amoun...

  14. Characterization of Lgr5+ progenitor cell transcriptomes in the apical and basal turns of the mouse cochlea

    Science.gov (United States)

    Zhang, Shasha; Chen, Yan; Zhang, Xiaoli; Wang, Lei; Tang, Mingliang; Shi, Haibo; Bird, Phillip I.; Li, Huawei; Chai, Renjie

    2016-01-01

    Lgr5+ supporting cells (SCs) are enriched hair cell (HC) progenitors in the cochlea, and several studies have shown a difference in the proliferation and HC regeneration ability of SCs between the apical and basal turns. However, the detailed differences between the transcriptomes of the apical and basal Lgr5+ SCs have not yet been investigated. We found that when isolated by FACS, Lgr5+ cells from the apex generated significantly more HCs and had significantly higher proliferation and mitotic HC regeneration ability compared to those from the base. Next, we used microarray analysis to determine the transcriptome expression profiles of Lgr5+ progenitors from the apex and the base. We first analyzed the genes that were enriched and differentially expressed in Lgr5+ progenitors from the apex and the base. Then we analyzed the cell cycle genes and the transcription factors that might regulate the proliferation and differentiation of Lgr5+ progenitors. Lastly, to further analyze the role of differentially expressed genes and to gain an overall view of the gene network in cochlear HC regeneration, we created a protein-protein interaction network. Our datasets suggest the possible genes that might regulate the proliferation and HC regeneration ability of Lgr5+ progenitors, and these genes might provide new therapeutic targets for HC regeneration in the future. PMID:27070092

  15. Myocardial edema in Takotsubo syndrome mimicking apical hypertrophic cardiomyopathy: An insight into diagnosis by cardiovascular magnetic resonance.

    Science.gov (United States)

    Izgi, Cemil; Ray, Sanjoy; Nyktari, Evangelia; Alpendurada, Francisco; Lyon, Alexander R; Rathore, Sudhir; Baksi, Arun John

    2015-01-01

    Myocardial edema is one of the characteristic features in the pathogenesis of Takotsubo syndrome. We report a middle aged man who presented with typical clinical and echocardiographic features of apical variant of Takotsubo syndrome. However, a cardiovascular magnetic resonance study performed 10 days after presentation did not show any apical 'ballooning' but revealed features of an apical hypertrophic cardiomyopathy on cine images. Tissue characterization with T2 weighted images proved severe edema as the cause of significantly increased apical wall thickness. A follow-up cardiovascular magnetic resonance study was performed 5 months later which showed that edema, wall thickening and the appearance of apical hypertrophic cardiomyopathy all resolved, confirming Takotsubo syndrome as the cause of the initial appearance. As the affected myocardium most commonly involves the apical segments, an edema induced increase in apical wall thickness may lead to appearances of an apical hypertrophic cardiomyopathy rather than apical ballooning in the acute to subacute phase of Takotsubo syndrome.

  16. Radial left ventricular dyssynchrony by speckle tracking in apical versus non apical right ventricular pacing- evidence of dyssynchrony on medium term follow up

    Directory of Open Access Journals (Sweden)

    Dinesh Choudhary

    2016-03-01

    Conclusion: Pacing in non apical location (RV mid septum or low RVOT is associated with less dyssynchrony by specific measures like 2D radial strain and correlates with better ventricular function in long term.

  17. Risk variables of external apical root resorption during orthodontic treatment

    Directory of Open Access Journals (Sweden)

    Maria Carolina Feio Barroso

    2012-04-01

    Full Text Available INTRODUCTION: External apical root resorption (EARR is an adverse outcome of the orthodontic treatment. So far, no single or associated factor has been identified as responsible for EARR due to tooth movement. OBJECTIVE: This study investigated the association of risk variables (age, gender, extraction for orthodontic treatment and Angle classification with EARR and orthodontic treatment. METHOD: The sample (n=72 was divided into two groups according to presence (n=32 or absence (n=40 of EARR in maxillary central and lateral incisors after orthodontic treatment. RESULTS: There were no statistically significant differences in EARR according to age, gender, extraction or type of malocclusion (p>0.05. CONCLUSION: The risk variables examined were not associated with EARR in the study population.

  18. Shoot apical meristem maintenance: the art of a dynamic balance.

    Science.gov (United States)

    Carles, Cristel C; Fletcher, Jennifer C

    2003-08-01

    The aerial structure of higher plants derives from cells at the tip of the stem, in the shoot apical meristem (SAM). Throughout the life of a plant, the SAM produces stem tissues and lateral organs, and also regenerates itself. For correct growth, the plant must maintain a constant flow of cells through the meristem, where the input of dividing pluripotent stem cells offsets the output of differentiating cells. This flow depends on extracellular signaling within the SAM, governed by a spatial regulatory feedback loop that maintains a reservoir of stem cells, and on factors that prevent meristem cells from differentiating prematurely. The terminating floral meristem incorporates the spatial regulation scheme into a temporal regulation pathway involving flower patterning factors.

  19. Geometry of shoot apical dome and distribution of growth rates

    Directory of Open Access Journals (Sweden)

    Jerzy Nakielski

    2014-01-01

    Full Text Available The distribution of the relative elementary rate of growth (RERG in apical domes of various shapes and patterns of displacement lines can be analytically examined. The geometry of these domes may be described by parabolas of n-th order, the variant of the distribution of linear growth rate should be established along any displacement line (e.g. along the axis and then the RERG can be studied as the function depending on the position coordinates and the parameter n. Such investigations of several aplical domes of various shapes have been performed. The results confirm the occurrence of the minimum of relative, elementary growth rate (in volume in the subapical region of the dome independently of the type of geometry (n parabola order.

  20. Cryopreservation of Galanthus elwesii Hook. apical meristems by droplet vitrification.

    Science.gov (United States)

    Maslanka, M; Panis, B; Bach, A

    2013-01-01

    The aim of this study was to develop an efficient cryopreservation protocol for the geophyte giant snowdrop (Galanthus elwesii Hook.) that guarantees a high rate of survival and plant regeneration after cryopreservation. The excised apical meristems were obtained from cultures of in vitro grown bulb scales. Using a vitrification procedure and optimizing the duration of the exposure to the loading solution (LS), meristem post-rewarm survival rates higher than 90 percent were achieved. Also regrowth percentages were very high, ranging from 87 to 91 percent. After optimizing the time of exposure to the plant vitrification solution (PVS2), the survival rate was between 83 and 97 percent. During post-rewarm regeneration, good growth recovery was as high as 76 percent; however, hyperhydration and callusing were also observed. The results demonstrate that cryopreservation of Galanthus elwesii germplasm seems to be feasible.

  1. Serious arrhythmias in patients with apical hypertrophic cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Okishige, Kaoru; Sasano, Tetsuo; Yano, Kei; Azegami, Kouji; Suzuki, Kou; Itoh, Kuniyasu [Yokohama Red Cross Hospital (Japan)

    2001-05-01

    We report cases of serious arrhythmias associated with apical hypertrophic cardiomyopathy (AHCM). Thirty-one patients were referred to our institute to undergo further assessment of their AHCM from 1988 to 1999. Three patients with nonsustained ventricular tachycardia demonstrated an {sup 123}I-MIBG regional reduction in the tracer uptake. In two patients with ventricular fibrillation (VF), the findings from {sup 123}I-MIBG imaging revealed regional sympathetic denervation in the inferior and lateral regions. Electrophysiologic study demonstrated reproducible induction of VF in aborted sudden death and presyncopal patients, resulting in the need for an implantable defibrillator device and amiodarone in each patient. Patients with refractory atrial fibrillation with a rapid ventricular response suffered from serious congestive heart failure. A prudent assessment and strategy in patients with this disease would be indispensable in avoiding a disastrous outcome. (author)

  2. Oral microbiota species in acute apical endodontic abscesses

    Directory of Open Access Journals (Sweden)

    Noelle George

    2016-03-01

    Full Text Available Background and objectives: Acute apical abscesses are serious endodontic diseases resulting from pulpal infection with opportunistic oral microorganisms. The objective of this study was to identify and compare the oral microbiota in patients (N=18 exhibiting acute apical abscesses, originating from the demographic region in Portland, Oregon. The study hypothesis is that abscesses obtained from this demographic region may contain unique microorganisms not identified in specimens from other regions. Design: Endodontic abscesses were sampled from patients at the Oregon Health & Science University (OHSU School of Dentistry. DNA from abscess specimens was subjected to polymerase chain reaction amplification using 16S rRNA gene-specific primers and Cy3-dCTP labeling. Labeled DNA was then applied to microbial microarrays (280 species generated by the Human Oral Microbial Identification Microarray Laboratory (Forsyth Institute, Cambridge, MA. Results: The most prevalent microorganisms, found across multiple abscess specimens, include Fusobacterium nucleatum, Parvimonas micra, Megasphaera species clone CS025, Prevotella multisaccharivorax, Atopobium rimae, and Porphyromonas endodontalis. The most abundant microorganisms, found in highest numbers within individual abscesses, include F. nucleatum, P. micra, Streptococcus Cluster III, Solobacterium moorei, Streptococcus constellatus, and Porphyromonas endodontalis. Strong bacterial associations were identified between Prevotella multisaccharivorax, Acidaminococcaceae species clone DM071, Megasphaera species clone CS025, Actinomyces species clone EP053, and Streptococcus cristatus (all with Spearman coefficients >0.9. Conclusions: Cultivable and uncultivable bacterial species have been identified in endodontic abscesses obtained from the Portland, Oregon demographic region, and taxa identifications correlated well with other published studies, with the exception of Treponema and Streptococcus cristae, which

  3. c-Yes regulates cell adhesion at the blood-testis barrier and the apical ectoplasmic specialization in the seminiferous epithelium of rat testes.

    Science.gov (United States)

    Xiao, Xiang; Mruk, Dolores D; Lee, Will M; Cheng, C Yan

    2011-04-01

    During spermatogenesis, extensive junction restructuring takes place at the blood-testis barrier (BTB) and the Sertoli cell-spermatid interface known as the apical ectoplasmic specialization (apical ES, a testis-specific adherens junction) in the seminiferous epithelium. However, the mechanism(s) that regulates these critical events in the testis remains unknown. Based on the current concept in the field, changes in the phosphorylation status of integral membrane proteins at these sites can induce alterations in protein endocytosis and recycling, causing junction restructuring. Herein, c-Yes, a non-receptor protein tyrosine kinase, was found to express abundantly at the BTB and apical ES stage-specifically, coinciding with junction restructuring events at these sites during the seminiferous epithelial cycle of spermatogenesis. c-Yes also structurally associated with adhesion proteins at the BTB (e.g., occludin and N-cadherin) and the apical ES (e.g., β1-integrin, laminins β3 and γ3), possibly to regulate phosphorylation status of proteins at these sites. SU6656, a selective c-Yes inhibitor, was shown to perturb the Sertoli cell tight junction-permeability barrier in vitro, which is mediated by changes in the distribution of occludin and N-cadherin at the cell-cell interface, moving from cell surface to cytosol, thereby destabilizing the tight junction-barrier. However, this disruptive effect of SU6656 on the barrier was blocked by testosterone. Furthermore, c-Yes is crucial to maintain the actin filament network in Sertoli cells since a blockade of c-Yes by SU6656 induced actin filament disorganization. In summary, c-Yes regulates BTB and apical ES integrity by maintaining proper distribution of integral membrane proteins and actin filament organization at these sites.

  4. Immunolocalization of FGF8/10 in the Apical Epidermal Peg and Blastema of the regenerating tail in lizard marks this apical growing area.

    Science.gov (United States)

    Alibardi, Lorenzo

    2016-07-01

    Previous studies have shown that Fibroblast Growth Factors are present in the regenerating tail tissues of lizards where they may stimulate the process of regeneration. The present study is focused on the immunolocalization of FGF8 and FGF10 in the regenerating lizard tail, two signaling proteins of the apical epidermal cup/ridge and mesenchymal blastema sustaining tail and limb regeneration in amphibians and the development of the tail and limbs in vertebrate embryos. Main immunoreactive protein bands at 15-18kDa for FGF8/10 are detected in the regenerating epidermis and only a band at 30 or 35kDa in the underlying connective tissues. FGF8 appears particularly localized in cells and nuclei of the apical epidermal peg and of the ependymal ampulla present at the tip of the regenerating tail. FGF10 is also immuno-localized in the apical epidermis but is particularly intensely localized in the mesenchyme of the apical blastema. In accordance with previous studies, the present observations supports the hypothesis that the apical epidermal peg and the ependymal tube with the few regenerated neurons present within it, release FGF8/10 that may contribute to maintenance of cell proliferation in the apical front of the mesenchyme for the growth of the regenerating tail.

  5. Alterations in Expression of F-actin and DNA of Fluid Shear Stress Treated-mesenchymal Stem Cells Affected by Titaninum Particles Loading%钛颗粒负荷对切应力作用下骨髓间质干细胞F-actin表达和DNA含量的影响

    Institute of Scientific and Technical Information of China (English)

    吴江; 陈槐卿; 曹慧; 周江; 张立; K-L Paul Sung

    2004-01-01

    假体磨损碎屑颗粒是引起假体-骨界面无菌性炎症和骨溶解而致全关节置换术失败的主要原因之一.磨屑颗粒所诱发的骨溶解须有周围骨组织中成骨细胞分泌足够的骨基质以弥补丢失的骨量,而成骨细胞正常的数量和质量有赖于其来源骨髓祖细胞-骨髓间质干细胞的正常增殖分化能力的维持.为了探讨磨屑钛颗粒对大鼠骨髓间质干细胞(Rat MSCs,rMSCs)产生细胞毒性的可能细胞分子机制, 选用健康3月龄SD雄性大鼠,采用Percoll等密度梯度离心法分离获取rMSCs,经体外传代纯化培养后,与不同直径、不同负荷浓度、不同负荷作用时间的钛颗粒悬液共孵育,再采用精准的流室系统对钛颗粒负荷的rMSCs施加一定的流体剪切应力(Fluid shear stress, FSS)后立刻固定细胞,经免疫荧光抗体染色,结合激光共聚焦显微镜技术和图像分析软件定性定量分析rMSCs F-actin表达和DNA含量的变化情况.同时设置相应的未经钛颗粒孵育的rMSCs细胞为对照组细胞.结果显示,切应力作用可上调rMSCs 胞内F-actin 的表达.亚微(Submicron)直径(0.9μm)的钛颗粒负荷对rMSCs F-actin表达和DNA含量的抑制作用最为显著,并伴有凋亡小体出现;直径为2.7μm的钛颗粒负荷产生的抑制作用略为减弱,而较大直径(6.9μm)的抑制效应最弱.相同条件下,钛颗粒负荷对F-actin的抑制效应有一定的时间和浓度依赖性:以0.1wt%浓度对F-actin表达和DNA含量的抑制效应最为明显,亦有凋亡小体的出现;随着浓度的降低,抑制作用亦减弱,以0.01wt%浓度最弱;随着作用时间的延长,F-actin表达和DNA含量逐渐降低,至实验中的32 h达到最低值.提示:磨屑颗粒对rMSCs活力的抑制作用是假体无菌性松动的可能分子机制,对其具体细胞分子机制进行深入研究,必将有助于有效防治假体松动药物的研发应用以及人工关节材料的优化设计,从而

  6. Prognostic factors in apical surgery with root-end filling: a meta-analysis

    DEFF Research Database (Denmark)

    von Arx, Thomas; Peñarrocha, Miguel; Jensen, Storgård

    2010-01-01

    Apical surgery has seen continuous development with regard to equipment and surgical technique. However, there is still a shortage of evidence-based information regarding healing determinants. The objective of this meta-analysis was to review clinical articles on apical surgery with root-end fill...

  7. Changes of Root Length and Root-to-Crown Ratio after Apical Surgery

    DEFF Research Database (Denmark)

    von Arx, Thomas; Jensen, Simon S; Bornstein, Michael M

    2015-01-01

    INTRODUCTION: Apical surgery is an important treatment option for teeth with post-treatment periodontitis. Although apical surgery involves root-end resection, no morphometric data are yet available about root-end resection and its impact on the root-to-crown ratio (RCR). The present study assess...

  8. Micro‐CT analyses of apical enlargement and molar root canal complexity

    DEFF Research Database (Denmark)

    Markvart, M.; Darvann, Tron Andre; Larsen, P.

    2012-01-01

    Markvart M, Darvann TA, Larsen P, Dalstra M, Kreiborg S, Bjørndal L. Micro‐CT analyses of apical enlargement and molar root canal complexity. International Endodontic Journal, 45, 273–281, 2012. Aim To compare the effectiveness of two rotary hybrid instrumentation techniques with focus on apical...

  9. Neisseria gonorrhoeae breaches the apical junction of polarized epithelial cells for transmigration by activating EGFR.

    Science.gov (United States)

    Edwards, Vonetta L; Wang, Liang-Chun; Dawson, Valerie; Stein, Daniel C; Song, Wenxia

    2013-06-01

    Neisseria gonorrhoeae initiates infection at the apical surface of columnar endocervical epithelial cells in the female reproductive tract. These cells provide a physical barrier against pathogens by forming continuous apical junctional complexes between neighbouring cells. This study examines the interaction of gonococci (GC) with polarized epithelial cells. We show that viable GC preferentially localize at the apical side of the cell-cell junction in polarized endometrial and colonic epithelial cells, HEC-1-B and T84. In GC-infected cells, continuous apical junctional complexes are disrupted, and the junction-associated protein β-catenin is redistributed from the apical junction to the cytoplasm and to GC adherent sites; however, overall cellular levels remain unchanged. This redistribution of junctional proteins is associated with a decrease in the 'fence' function of the apical junction but not its 'gate' function. Disruption of the apical junction by removing calcium increases GC transmigration across the epithelial monolayer. GC inoculation induces the phosphorylation of both epidermal growth factor receptor (EGFR) and β-catenin, while inhibition of EGFR kinase activity significantly reduces both GC-induced β-catenin redistribution and GC transmigration. Therefore, the gonococcus is capable of weakening the apical junction and polarity of epithelial cells by activating EGFR, which facilitates GC transmigration across the epithelium.

  10. Aquaporin-2: COOH terminus is necessary but not sufficient for routing to the apical membrane.

    NARCIS (Netherlands)

    Deen, P.M.T.; Balkom, B.W.M. van; Savelkoul, P.J.M.; Kamsteeg, E.J.; Raak, M.M.J.P. van; Jennings, M.L.; Muth, T.R.; Rajendran, V.; Caplan, M.J.

    2002-01-01

    Renal regulation of mammalian water homeostasis is mediated by the aquaporin-1 (AQP1) water channel, which is expressed in the apical and basolateral membranes of proximal tubules and descending limbs of Henle, and aquaporin-2 (AQP2), which is redistributed from intracellular vesicles to the apical

  11. Determination of working length for teeth with wide or immature apices: a review.

    Science.gov (United States)

    Kim, Y J A; Chandler, N P

    2013-06-01

    Practitioners face several challenges during the root canal treatment of teeth with wide or immature apices, one of which is working length determination. There is relatively little data regarding the value of radiography and electronic apex locator (EAL) use when root formation is incomplete, and supplementary measurement techniques may be helpful. This review considers length determination for canals with wide or completely open apices in permanent and primary teeth. The Ovid Medline, Web of Science and Scopus databases were searched individually and in combinations to August 2012 using the subject headings 'working length determination' and 'open apex' and revealed only one article. Further headings, 'tooth apex', 'apical constriction', 'resorption', 'foramen size', 'mature root apex', 'immature root apex', 'working length determination', 'apexification', 'open apices', 'open apex', 'open apical foramina', 'canal length determination', 'immature teeth', 'apical diameters', 'electronic apex locators', 'primary teeth', 'treatment outcome' and 'clinical outcome' were entered. Potentially useful articles were chosen for a manual search of bibliography as well as a forward search of citations. Other investigations revealed case reports and some research related to open apices and laboratory studies evaluating EALs, radiography and tactile methods. Some involved permanent teeth of various apical diameters and primary teeth with and without resorption. There is a need to define the term 'open apex'. Clinicians should be aware of the benefits and limitations of all canal measuring techniques involved in managing this problem.

  12. Discerning apical and basolateral properties of HT-29/B6 and IPEC-J2 cell layers by impedance spectroscopy, mathematical modeling and machine learning.

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    Thomas Schmid

    Full Text Available Quantifying changes in partial resistances of epithelial barriers in vitro is a challenging and time-consuming task in physiology and pathophysiology. Here, we demonstrate that electrical properties of epithelial barriers can be estimated reliably by combining impedance spectroscopy measurements, mathematical modeling and machine learning algorithms. Conventional impedance spectroscopy is often used to estimate epithelial capacitance as well as epithelial and subepithelial resistance. Based on this, the more refined two-path impedance spectroscopy makes it possible to further distinguish transcellular and paracellular resistances. In a next step, transcellular properties may be further divided into their apical and basolateral components. The accuracy of these derived values, however, strongly depends on the accuracy of the initial estimates. To obtain adequate accuracy in estimating subepithelial and epithelial resistance, artificial neural networks were trained to estimate these parameters from model impedance spectra. Spectra that reflect behavior of either HT-29/B6 or IPEC-J2 cells as well as the data scatter intrinsic to the used experimental setup were created computationally. To prove the proposed approach, reliability of the estimations was assessed with both modeled and measured impedance spectra. Transcellular and paracellular resistances obtained by such neural network-enhanced two-path impedance spectroscopy are shown to be sufficiently reliable to derive the underlying apical and basolateral resistances and capacitances. As an exemplary perturbation of pathophysiological importance, the effect of forskolin on the apical resistance of HT-29/B6 cells was quantified.

  13. Apical Ca2+-activated potassium channels in mouse parotid acinar cells.

    Science.gov (United States)

    Almassy, Janos; Won, Jong Hak; Begenisich, Ted B; Yule, David I

    2012-02-01

    Ca(2+) activation of Cl and K channels is a key event underlying stimulated fluid secretion from parotid salivary glands. Cl channels are exclusively present on the apical plasma membrane (PM), whereas the localization of K channels has not been established. Mathematical models have suggested that localization of some K channels to the apical PM is optimum for fluid secretion. A combination of whole cell electrophysiology and temporally resolved digital imaging with local manipulation of intracellular [Ca(2+)] was used to investigate if Ca(2+)-activated K channels are present in the apical PM of parotid acinar cells. Initial experiments established Ca(2+)-buffering conditions that produced brief, localized increases in [Ca(2+)] after focal laser photolysis of caged Ca(2+). Conditions were used to isolate K(+) and Cl(-) conductances. Photolysis at the apical PM resulted in a robust increase in K(+) and Cl(-) currents. A localized reduction in [Ca(2+)] at the apical PM after photolysis of Diazo-2, a caged Ca(2+) chelator, resulted in a decrease in both K(+) and Cl(-) currents. The K(+) currents evoked by apical photolysis were partially blocked by both paxilline and TRAM-34, specific blockers of large-conductance "maxi-K" (BK) and intermediate K (IK), respectively, and almost abolished by incubation with both antagonists. Apical TRAM-34-sensitive K(+) currents were also observed in BK-null parotid acini. In contrast, when the [Ca(2+)] was increased at the basal or lateral PM, no increase in either K(+) or Cl(-) currents was evoked. These data provide strong evidence that K and Cl channels are similarly distributed in the apical PM. Furthermore, both IK and BK channels are present in this domain, and the density of these channels appears higher in the apical versus basolateral PM. Collectively, this study provides support for a model in which fluid secretion is optimized after expression of K channels specifically in the apical PM.

  14. Evaluation of apical subtype of hypertrophic cardiomyopathy using cardiac magnetic resonance imaging with gadolinium enhancement.

    Science.gov (United States)

    Kebed, Kalie Y; Al Adham, Raed I; Bishu, Kalkidan; Askew, J Wells; Klarich, Kyle W; Araoz, Philip A; Foley, Thomas A; Glockner, James F; Nishimura, Rick A; Anavekar, Nandan S

    2014-09-01

    Apical hypertrophic cardiomyopathy (HC) is an uncommon variant of HC. We sought to characterize cardiac magnetic resonance imaging (MRI) findings among apical HC patients. This was a retrospective review of consecutive patients with a diagnosis of apical HC who underwent cardiac MRI examinations at the Mayo Clinic (Rochester, MN) from August 1999 to October 2011. Clinical and demographic data at the time of cardiac MRI study were abstracted. Cardiac MRI study and 2-dimensional echocardiograms performed within 6 months of the cardiac MRI were reviewed; 96 patients with apical HC underwent cardiac MRI examinations. LV end-diastolic and end-systolic volumes were 130.7 ± 39.1 ml and 44.2 ± 20.9 ml, respectively. Maximum LV thickness was 19 ± 5 mm. Hypertrophy extended beyond the apex into other segments in 57 (59.4%) patients. Obstructive physiology was seen in 12 (12.5%) and was more common in the mixed apical phenotype than the pure apical (19.3 vs 2.6%, p = 0.02). Apical pouches were noted in 39 (40.6%) patients. Late gadolinium enhancement (LGE) was present in 70 (74.5%) patients. LGE was associated with severe symptoms and increased maximal LV wall thickness. In conclusion, cardiac MRI is well suited for studying the apical form of HC because of difficulty imaging the cardiac apex with standard echocardiography. Cardiac MRI is uniquely suited to delineate the presence or absence of an apical pouch and abnormal myocardial LGE that may have implications in the natural history of apical HM. In particular, the presence of abnormal LGE is associated with clinical symptoms and increased wall thickness.

  15. Pro-oxidant status and matrix metalloproteinases in apical lesions and gingival crevicular fluid as potential biomarkers for asymptomatic apical periodontitis and endodontic treatment response

    Directory of Open Access Journals (Sweden)

    Dezerega Andrea

    2012-03-01

    Full Text Available Abstract Background Oxidative stress and matrix metalloproteinases -9 and -2 are involved in periodontal breakdown, whereas gingival crevicular fluid has been reported to reflect apical status. The aim of this study was to characterize oxidant balance and activity levels of MMP -2 and -9 in apical lesions and healthy periodontal ligament; and second, to determine whether potential changes in oxidant balance were reflected in gingival crevicular fluid from asymptomatic apical periodontitis (AAP-affected teeth at baseline and after endodontic treatment. Methods Patients with clinical diagnosis of AAP and healthy volunteers having indication of tooth extraction were recruited. Apical lesions and healthy periodontal ligaments, respectively, were homogenized or processed to obtain histological tissue sections. Matrix metalloproteinase -9 and -2 levels and/or activity were analyzed by Immunowestern blot, zymography and consecutive densitometric analysis, and their tissue localization was confirmed by immunohistochemistry. A second group of patients with AAP and indication of endodontic treatment was recruited. Gingival crevicular fluid was extracted from AAP-affected teeth at baseline, after endodontic treatment and healthy contralateral teeth. Total oxidant and antioxidant status were determined in homogenized tissue and GCF samples. Statistical analysis was performed using STATA v10 software with unpaired t test, Mann-Whitney test and Spearman's correlation. Results Activity of MMP-2 and MMP-9 along with oxidant status were higher in apical lesions (p Conclusions Apical lesions display an oxidant imbalance along with increased activity of matrix metalloproteinase-2 and -9 and might contribute to AAP progression. Oxidant imbalance can also be reflected in GCF from AAP-affected teeth and was restored to normal levels after conservative endodontic treatment. These mediators might be useful as potential biomarkers for chair-side complementary diagnostic

  16. Comparison of apical sealing and periapical extrusion of the ThermaFil obturation technique with and without MTA as an apical barrier: An in vitro study

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    Satish Kumar

    2011-01-01

    Full Text Available Aim: The aim of the study was to compare the conventional ThermaFil obturation technique and ThermaFil obturation with mineral trioxide aggregate (MTA as an apical barrier, with regard to apical sealing and extrusion. Materials and Methods: Twenty extracted human canines were instrumented using a crown-down technique and divided into two groups. The experimental group was obturated using ThermaFil obturation with MTA as an apical barrier and the control group was obturated using the conventional ThermaFil obturation technique. AH Plus sealer was used in both the groups. Apical extrusion was recorded. Teeth of both the groups were coated with nail polish, except for the apical 3 mm. After 24 h, they were suspended in black India ink for 48 h. Canines were decalcified, rendered transparent, and linear dye penetration was measured under ×40 stereomicroscope. Results: There was a significant extrusion noticed in conventional ThermaFil obturation technique. Frequency of extrusion of sealer and/or gutta-percha was supposed to be evaluated using χ² test, but since the values of the samples of ThermaFil plus MTA group were zero, statistical analysis could not be conducted, whereas linear dye leakage was calculated with Mann-Whitney U test because the distribution was abnormal. Conclusion: Although ThermaFil plus MTA group showed microleakage, extrusion of sealer and the core material was prevented in comparison with conventional ThermaFil obturation technique. It is advantageous to use MTA as an apical plug as there is no fear of apical extrusion and the root canal system can then be packed three dimensionally against this barrier using any thermoplasticized gutta-percha obturation technique.

  17. Connective Auxin Transport in the Shoot Facilitates Communication between Shoot Apices.

    Science.gov (United States)

    Bennett, Tom; Hines, Geneviève; van Rongen, Martin; Waldie, Tanya; Sawchuk, Megan G; Scarpella, Enrico; Ljung, Karin; Leyser, Ottoline

    2016-04-01

    The bulk polar movement of the plant signaling molecule auxin through the stem is a long-recognized but poorly understood phenomenon. Here we show that the highly polar, high conductance polar auxin transport stream (PATS) is only part of a multimodal auxin transport network in the stem. The dynamics of auxin movement through stems are inconsistent with a single polar transport regime and instead suggest widespread low conductance, less polar auxin transport in the stem, which we term connective auxin transport (CAT). The bidirectional movement of auxin between the PATS and the surrounding tissues, mediated by CAT, can explain the complex auxin transport kinetics we observe. We show that the auxin efflux carriers PIN3, PIN4, and PIN7 are major contributors to this auxin transport connectivity and that their activity is important for communication between shoot apices in the regulation of shoot branching. We propose that the PATS provides a long-range, consolidated stream of information throughout the plant, while CAT acts locally, allowing tissues to modulate and be modulated by information in the PATS.

  18. HANABA TARANU regulates the shoot apical meristem and leaf development in cucumber (Cucumis sativus L.).

    Science.gov (United States)

    Ding, Lian; Yan, Shuangshuang; Jiang, Li; Liu, Meiling; Zhang, Juan; Zhao, Jianyu; Zhao, Wensheng; Han, Ying-Yan; Wang, Qian; Zhang, Xiaolan

    2015-12-01

    The shoot apical meristem (SAM) is essential for continuous organogenesis in higher plants, while the leaf is the primary source organ and the leaf shape directly affects the efficiency of photosynthesis. HANABA TARANU (HAN) encodes a GATA3-type transcription factor that functions in floral organ development, SAM organization, and embryo development in Arabidopsis, but is involved in suppressing bract outgrowth and promoting branching in grass species. Here the function of the HAN homologue CsHAN1 was characterized in cucumber, an important vegetable with great agricultural and economic value. CsHAN1 is predominantly expressed at the junction of the SAM and the stem, and can partially rescue the han-2 floral organ phenotype in Arabidopsis. Overexpression and RNAi of CsHAN1 transgenic cucumber resulted in retarded growth early after embryogenesis and produced highly lobed leaves. Further, it was found that CsHAN1 may regulate SAM development through regulating the WUSCHEL (WUS) and SHOOT MERISTEMLESS (STM) pathways, and mediate leaf development through a complicated gene regulatory network in cucumber.

  19. Structural development and energy dissipation in simulated silicon apices

    Directory of Open Access Journals (Sweden)

    Samuel Paul Jarvis

    2013-12-01

    Full Text Available In this paper we examine the stability of silicon tip apices by using density functional theory (DFT calculations. We find that some tip structures - modelled as small, simple clusters - show variations in stability during manipulation dependent on their orientation with respect to the sample surface. Moreover, we observe that unstable structures can be revealed by a characteristic hysteretic behaviour present in the F(z curves that were calculated with DFT, which corresponds to a tip-induced dissipation of hundreds of millielectronvolts resulting from reversible structural deformations. Additionally, in order to model the structural evolution of the tip apex within a low temperature NC-AFM experiment, we simulated a repeated tip–surface indentation until the tip structure converged to a stable termination and the characteristic hysteretic behaviour was no longer observed. Our calculations suggest that varying just a single rotational degree of freedom can have as measurable an impact on the tip–surface interaction as a completely different tip structure.

  20. Poda apical para uniformizar a colheita de flores de ?tango?

    Directory of Open Access Journals (Sweden)

    Francine Lorena Cuquel

    1999-01-01

    Full Text Available Este trabalho testou a poda apical das hastes de tango 4 e 6 semanas após a roçada, para homogeneizar a colheita que, comercialmente, necessita ser feita por um período de aproximadamente 5 dias numa mesma área. Foram avaliados altura média das plantas no primeiro dia de colheita, número médio de hastes colhidas/planta e a média do peso de matéria seca colhida/haste. Só foi verificada diferença significativa para altura média das plantas no primeiro dia de colheita, não se conseguindo reduzir o número de colheitas necessárias por planta. Existem indicações de que há necessidade de reduzir a variabilidade genética da população para homogeneizar a colheita de inflorescências de tango.

  1. Radiographic evaluation of apical root resorption following fixed orthodontic treatment

    Directory of Open Access Journals (Sweden)

    Sina Haghanifar

    2012-01-01

    Full Text Available Background and Aims: Apical root resorption is an adverse side effect of fixed orthodontic treatment which cannot be repaired. The aim of this study was to use panoramic radiographs to compare the root resorption before and after the orthodontic treatment with standard edgewise .018 appliance.Materials and Methods: The before and after treatment panoramic views of sixty-three patients needed fixed orthodontic treatment included 1520 teeth were categorized into 3 Grades (G0: without resorption, G1: mild resorption with blunt roots or ≤ 1/4 of root length, G2: moderate to severe resorption or > 1/4 to 1/2 of root length. Relationship between root resorption and sex and treatment duration was analyzed with Mann-whitney and Spearman's correlation coefficient, respectively.Results: The findings showed that 345 teeth were categorized as Grade 1. Grade 2 of root resorption was not found in this study. The highest amount of root resorption was recorded for the mandibular lateral incisor. In both gender, the root resorption of the mandible was more than that of the maxilla. The males showed significantly higher rate of resorption than the females (P0.05.Conclusion: The mandible and male patients showed higher amount of root resorption. In addition, root resorption was not related to the treatment duration and the side of the jaws.

  2. The apical complex provides a regulated gateway for secretion of invasion factors in Toxoplasma.

    Directory of Open Access Journals (Sweden)

    Nicholas J Katris

    2014-04-01

    Full Text Available The apical complex is the definitive cell structure of phylum Apicomplexa, and is the focus of the events of host cell penetration and the establishment of intracellular parasitism. Despite the importance of this structure, its molecular composition is relatively poorly known and few studies have experimentally tested its functions. We have characterized a novel Toxoplasma gondii protein, RNG2, that is located at the apical polar ring--the common structural element of apical complexes. During cell division, RNG2 is first recruited to centrosomes immediately after their duplication, confirming that assembly of the new apical complex commences as one of the earliest events of cell replication. RNG2 subsequently forms a ring, with the carboxy- and amino-termini anchored to the apical polar ring and mobile conoid, respectively, linking these two structures. Super-resolution microscopy resolves these two termini, and reveals that RNG2 orientation flips during invasion when the conoid is extruded. Inducible knockdown of RNG2 strongly inhibits host cell invasion. Consistent with this, secretion of micronemes is prevented in the absence of RNG2. This block, however, can be fully or partially overcome by exogenous stimulation of calcium or cGMP signaling pathways, respectively, implicating the apical complex directly in these signaling events. RNG2 demonstrates for the first time a role for the apical complex in controlling secretion of invasion factors in this important group of parasites.

  3. Apical constriction initiates new bud formation during monopodial branching of the embryonic chicken lung

    Science.gov (United States)

    Kim, Hye Young; Varner, Victor D.; Nelson, Celeste M.

    2013-01-01

    Branching morphogenesis sculpts the airway epithelium of the lung into a tree-like structure to conduct air and promote gas exchange after birth. In the avian lung, a series of buds emerges from the dorsal surface of the primary bronchus via monopodial branching to form the conducting airways; anatomically, these buds are similar to those formed by domain branching in the mammalian lung. Here, we show that monopodial branching is initiated by apical constriction of the airway epithelium, and not by differential cell proliferation, using computational modeling and quantitative imaging of embryonic chicken lung explants. Both filamentous actin and phosphorylated myosin light chain were enriched at the apical surface of the airway epithelium during monopodial branching. Consistently, inhibiting actomyosin contractility prevented apical constriction and blocked branch initiation. Although cell proliferation was enhanced along the dorsal and ventral aspects of the primary bronchus, especially before branch formation, inhibiting proliferation had no effect on the initiation of branches. To test whether the physical forces from apical constriction alone are sufficient to drive the formation of new buds, we constructed a nonlinear, three-dimensional finite element model of the airway epithelium and used it to simulate apical constriction and proliferation in the primary bronchus. Our results suggest that, consistent with the experimental results, apical constriction is sufficient to drive the early stages of monopodial branching whereas cell proliferation is dispensable. We propose that initial folding of the airway epithelium is driven primarily by apical constriction during monopodial branching of the avian lung. PMID:23824575

  4. The large GTPase Mx1 is involved in apical transport in MDCK cells.

    Science.gov (United States)

    Hoff, Florian; Greb, Christoph; Hollmann, Christina; Hönig, Ellena; Jacob, Ralf

    2014-09-01

    In epithelial cells apical proteins are transported by specific transport carriers to the correct membrane domain. The composition of these carriers is heterogeneous and comprises components such as motor proteins, annexins, lectins, Rab GTPases and cargo molecules. Here, we provide biochemical and fluorescence microscopic data to show that the dynamin-related large GTPase Mx1 is a component of post-Golgi vesicles carrying the neurotrophin receptor p75(NTR) . Moreover, siRNA-mediated depletion of Mx1 significantly decreased the transport efficiency of apical proteins in MDCK cells. In conclusion, Mx1 plays a crucial role in the delivery of cargo molecules to the apical membrane of epithelial cells.

  5. Obturating teeth with wide open apices using mineral trioxide aggregate: a case report.

    Science.gov (United States)

    Levenstein, H

    2002-07-01

    The conventional approach in handling a tooth with a wide open apex requiring endodontic treatment is by means of a procedure called apexification. The objective of treatment is to introduce calcium hydroxide mixed with sterile water or local anaesthetic into the root canal to create a hard-tissue-like formation or an apical plug to prevent extrusion of filling materials during obturation of teeth with wide open apices. This procedure may take anything from 6 months to 2 years. In 1999 a new material called mineral trioxide aggregate (MTA) was introduced to the dental profession for clinical use which has the ability to create an apical plug within a few weeks.

  6. Pulp microbiology of complete teeth with idiopathic apical lesions.

    Directory of Open Access Journals (Sweden)

    Patricia Rodríguez

    2009-11-01

    Full Text Available Introduction: Periapical changes named as lesions, in teeth with full crown integrity and without history of trauma, do not show a clear aetiology. Objective: To determine the presence of microorganisms in pulp dental tissue will clarify the cause of its death and therefore the damage to periodontal tissues. Materials and methods: From people between 10 and 39 years old, 23 teeth were selected. The samples were taken with paper points and 0.8 sterile files, and were transported in VMGA III medium, to be processed in the following 24 hours after they were taken and sowed in Brucella-agar. Results: The most affected teeth were upper central incisors, 43.8%. From the 23 studied teeth, microbiological grow was seen on 20 teeth. The following microorganisms species were identified: Fusobacterium spp., 25%, Eubacterium spp., 15%; Peptostreptococcus spp., 10%; Campylobacter spp., 10%; gram negative enteric bacteria, 10%; Porphyromonas gingivalis, 10%; Prevotella intermedia, 5%; Eikenellia corrodens, 5%; Dialister pneumosintes, 5%; and yeasts, 5%. There was no growing evidence of Actinomyces actinomycetemcomitans, Tanerella forsythensis and Streptococcus β  hemolytic. Discussion and conclusions: Sound pulp dental tissue is sterile; an injury over it will cause its inflammation, degeneration, death and bacterial contamination. Results in the present study clearly show the presence of microorganisms in closed apical dental lesions of endodontic origin. In same manner, it was seen that a great part of microorganisms species found can be regarded as periodontal pathogens. This could suggest a management with an endodontic, a periodontic and a pharmacological combined treatment.

  7. Frecuencia de periodontitis apical en tratamientos endodónticos de pregrado Frequency of apical periodontitis in endodontic treatment in undergraduate

    OpenAIRE

    León, P; MJ Ilabaca; Alcota,M; FE González

    2011-01-01

    La periodontitis apical es una enfermedad de los tejidos periapicales de etiología bacteriana. Su tratamiento requiere erradicar los microorganismos del conducto radicular y obturarlo para lograr la reparación posterior. El objetivo de éste trabajo fue determinar la frecuencia de periodontitis apical en la población que asiste a la clínica de Endodoncia de la Facultad de Odontología de la Universidad de Chile y su relación con diferentes variables: diagnóstico específico, edad, sexo, agudas v...

  8. CCS52A2/FZR1, a cell cycle regulator, is an essential factor for shoot apical meristem maintenance in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Liu Yajie

    2012-08-01

    Full Text Available Abstract Background Cell division and cell fate decisions regulate organ formation and function in plant growth and development. It is still unclear how specific meristematic regulatory networks operate with the cell cycle machinery to translate stem cell identity and maintenance into cellular behavior. In this study, we address these questions by analysis of a shoot apex defective mutant, namely xcm9. Results Phenotypic analysis of the xcm9 mutant reveals concomitant premature termination of floral shoots with frequent bifurcation of the shoot apices, stems, and flowers. Microscopic observations show irregular cell organization in shoot apical meristems of xcm9. Positional cloning revealed that xcm9 is a loss of function allele of the CCS52A2/FZR1 gene, which has previously been implicated in root development. Expression analysis demonstrated that CCS52A2 maintains a higher transcriptional expression level in actively dividing tissue. Genetic studies indicated that the CCS52A2 gene functions together with WUSCHEL (WUS and CLAVATA3 (CLV3 in regulating the development of the shoot meristem, and also contributes to this regulation together with the chromatin remodeling pathway. In addition, fewer xcm9 cells express CYCLIN B1:1, showing that cell cycle progression is disrupted in the mutant. Conclusion We propose that the CCS52A2 gene is a mediator that functions together with meristematic genes to regulate meristem organization, and cross-functions with chromatin regulators in cell cycle progression during shoot apical meristem development.

  9. Chimaerin suppresses Rac1 activation at the apical membrane to maintain the cyst structure.

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    Shunsuke Yagi

    Full Text Available Epithelial organs are made of a well-polarized monolayer of epithelial cells, and their morphology is maintained strictly for their proper functions. Previously, we showed that Rac1 activation is suppressed at the apical membrane in the mature organoid, and that such spatially biased Rac1 activity is required for the polarity maintenance. Here we identify Chimaerin, a GTPase activating protein for Rac1, as a suppressor of Rac1 activity at the apical membrane. Depletion of Chimaerin causes over-activation of Rac1 at the apical membrane in the presence of hepatocyte growth factor (HGF, followed by luminal cell accumulation. Importantly, Chimaerin depletion did not inhibit extension formation at the basal membrane. These observations suggest that Chimaerin functions as the apical-specific Rac1 GAP to maintain epithelial morphology.

  10. Rho/Rho-associated Kinase-II Signaling Mediates Disassembly of Epithelial Apical Junctions

    OpenAIRE

    2007-01-01

    Apical junctional complex (AJC) plays a vital role in regulation of epithelial barrier function. Disassembly of the AJC is observed in diverse physiological and pathological states; however, mechanisms governing this process are not well understood. We previously reported that the AJC disassembly is driven by the formation of apical contractile acto-myosin rings. In the present study, we analyzed the signaling pathways regulating acto-myosin–dependent disruption of AJC by using a model of ext...

  11. Descriptive study of apical periodontitis detected in Cone Beam Computed Tomography scans

    OpenAIRE

    MORETI,Lucieni Cristina Trovati; PANZARELLA,Francine Kühl; OLIVEIRA,Marine de; José Luiz Cintra JUNQUEIRA; MANHÃES JÚNIOR,Luiz Roberto

    2016-01-01

    ABSTRACT Objective: To perform a descriptive study in order to evaluate apical periodontitis in endodontically treated teeth using cone beam computed tomography. Methods: Eighty-six exams presenting at least one apical periodontitis were selected and divided into two groups: 1 for the mandible and 2 for the maxilla. All the exams were done using the same cone beam computed tomography with standard acquisition settings. All the images were processed and manipulated using the same software. T...

  12. Isolated left ventricular apical hypoplasia with infundibular pulmonary and aortic stenosis: A rare combination

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Jin Il; Jeong, Yeon Joo; Lee, Gee Won; Choi, Jung Hyun; Lee, Ji Won [Medical Research Institute, Pusan National University Hospital, Busan (Korea, Republic of)

    2013-12-15

    Isolated left ventricular (LV) apical hypoplasia is a rare congenital cardiac anomaly which is not accompanied by other cardiac abnormalities, with the exception of two cases. We report a case of a 33-year-old male patient with isolated LV apical hypoplasia combined with infundibular pulmonary stenosis and aortic stenosis. We review a literature focusing on the characteristic magnetic resonance features and combined cardiac abnormalities.

  13. The dynamics of soybean leaf and shoot apical meristem transcriptome undergoing floral initiation process.

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    Chui E Wong

    Full Text Available Flowering process governs seed set and thus affects agricultural productivity. Soybean, a major legume crop, requires short-day photoperiod conditions for flowering. While leaf-derived signal(s are essential for the photoperiod-induced floral initiation process at the shoot apical meristem, molecular events associated with early floral transition stages in either leaves or shoot apical meristems are not well understood. To provide novel insights into the molecular basis of floral initiation, RNA-Seq was used to characterize the soybean transcriptome of leaf and micro-dissected shoot apical meristem at different time points after short-day treatment. Shoot apical meristem expressed a higher number of transcripts in comparison to that of leaf highlighting greater diversity and abundance of transcripts expressed in the shoot apical meristem. A total of 2951 shoot apical meristem and 13,609 leaf sequences with significant profile changes during the time course examined were identified. Most changes in mRNA level occurred after 1short-day treatment. Transcripts involved in mediating responses to stimulus including hormones or in various metabolic processes represent the top enriched GO functional category for the SAM and leaf dataset, respectively. Transcripts associated with protein degradation were also significantly changing in leaf and SAM implicating their involvement in triggering the developmental switch. RNA-Seq analysis of shoot apical meristem and leaf from soybean undergoing floral transition reveal major reprogramming events in leaves and the SAM that point toward hormones gibberellins (GA and cytokinin as key regulators in the production of systemic flowering signal(s in leaves. These hormones may form part of the systemic signals in addition to the established florigen, FLOWERING LOCUS T (FT. Further, evidence is emerging that the conversion of shoot apical meristem to inflorescence meristem is linked with the interplay of auxin

  14. Frecuencia de periodontitis apical en tratamientos endodónticos de pregrado Frequency of apical periodontitis in endodontic treatment in undergraduate

    Directory of Open Access Journals (Sweden)

    P León

    2011-12-01

    Full Text Available La periodontitis apical es una enfermedad de los tejidos periapicales de etiología bacteriana. Su tratamiento requiere erradicar los microorganismos del conducto radicular y obturarlo para lograr la reparación posterior. El objetivo de éste trabajo fue determinar la frecuencia de periodontitis apical en la población que asiste a la clínica de Endodoncia de la Facultad de Odontología de la Universidad de Chile y su relación con diferentes variables: diagnóstico específico, edad, sexo, agudas vs. crónicas, éxito/fracaso del tratamiento y rehabilitación post-tratamiento. Se recolectó información de 292 dientes de pacientes tratados en dicha clínica, analizándose la información de aquellos con dientes diagnosticados con algún tipo de periodontitis apical clasificándolo según la nueva nomenclatura de la asociación de endodoncia americana. La frecuencia de periodontitis apical fue de un 36.7% (92 pacientes, de los cuales un 77.8% presentaron patologías de tipo crónicas. Un 75% de los pacientes pertenecieron al sexo femenino y la 5ta década representó un 34.8% de los pacientes. El 100% de los pacientes que acudieron a control presentó éxito en sus tratamientos según variables clínico-radiográficas, mientras que la restauración más frecuente post-tratamiento fue la resina compuesta (52.4%. Dado el pequeño número de pacientes que concurrieron a la citación de control para determinar el éxito del tratamiento, esta variable debe ser considerada como preliminar. Nuestros resultados mostraron que la condición mas frecuente fue la periodontitis apical de tipo crónica, afectando más a mujeres y a la 5ta década.Apical periodontitis is a microbially induced inflammatory disease of the periapical tissues. Its treatment requires eliminating microorganism from root canal and sealing it properly to induce further tissue repair. The aim of this study was to determine the frequency of apical periodontitis and its distribution by

  15. Calcium-enriched mixture cement as artificial apical barrier: A case series

    Directory of Open Access Journals (Sweden)

    Ali Nosrat

    2011-01-01

    Full Text Available In comparison to the conventional apexification using calcium hydroxide, artificial apical barrier technique is more valuable and less time consuming. This article describes successful use of calcium-enriched mixture (CEM cement as an artificial apical barrier in open apices. In this study, 13 single-rooted teeth with necrotic pulps and open apices were treated non-surgically. After copious irrigation of the root canals with NaOCl 5.25% and gentle filing, based on need for interappointment dressing, treatments were followed by CEM cement (BioniqueDent, Tehran, Iran apical plug insertion in the first or second appointment. All cases were then permanently restored. All subjects were followed until radiographic evidence of periradicular healing was seen (mean 14.5 months. Clinically, all cases were functional and asymptomatic and complete osseous healing was observed in all the teeth. Considering the biological properties of CEM cement, this new endodontic biomaterial might be appropriate to be used as artificial apical barrier in the open apex teeth.

  16. Criticalities in crosslinked actin networks due to myosin activity

    Science.gov (United States)

    Sheinman, Michael

    2013-03-01

    Many essential processes in cells and tissues, like motility and morphogenesis, are orchestrated by molecular motors applying internal, active stresses on crosslinked networks of actin filaments. Using scaling analysis, mean-field calculation, numerical modelling and in vitro experiments of such active networks we predict and observe different mechanical regimes exhibiting interesting critical behaviours with non-trivial power-law dependencies. Firstly, we find that the presence of active stresses can dramatically increase the stiffness of a floppy network, as was observed in reconstituted intracellular F-actin networks with myosin motors and extracellular gels with contractile cells. Uniform internal stress results in an anomalous, critical mechanical regime only in the vicinity of the rigidity percolation points of the network. However, taking into account heterogeneity of motors, we demonstrate that the motors, stiffening any floppy network, induce large non-affine fluctuations, giving rise to a critical mechanical regime. Secondly, upon increasing motor concentration, the resulting large internal stress is able to significantly enhance unbinding of the network's crosslinks and, therefore, disconnect the initially well-connected network to isolated clusters. However, during this process, when the network approaches marginal connectivity the internal stresses are expected to drop drastically such that the connectivity stabilizes. This general argument and detailed numerical simulations show that motors should drive a well connected network to a close vicinity of a critical point of marginal connectivity. Experiments clearly confirm this conclusion and demonstrate robust critical connectivity of initially well-connected networks, ruptured by the motor activity for a wide range of parameters. M. Sheinman, C.P. Broedersz and F.C. MacKintosh, Phys. Rev. Lett, in press. J. Alvarado, M. Sheinman, A. Sharma, F.C. MacKintosh and G. Koenderink, in preparation.

  17. Incidence of apical root cracks and apical dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths

    NARCIS (Netherlands)

    Liu, R.; Kaiwar, A.; Shemesh, H.; Wesselink, P.R.; Hou, B.; Wu, M.K.

    2013-01-01

    Introduction The aim of this study was to compare the incidence of apical root cracks and dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths. Methods Two hundred forty mandibular incisors were mounted in resin blocks with simulated periodonta

  18. Mechanical roles of apical constriction, cell elongation, and cell migration during neural tube formation in Xenopus.

    Science.gov (United States)

    Inoue, Yasuhiro; Suzuki, Makoto; Watanabe, Tadashi; Yasue, Naoko; Tateo, Itsuki; Adachi, Taiji; Ueno, Naoto

    2016-12-01

    Neural tube closure is an important and necessary process during the development of the central nervous system. The formation of the neural tube structure from a flat sheet of neural epithelium requires several cell morphogenetic events and tissue dynamics to account for the mechanics of tissue deformation. Cell elongation changes cuboidal cells into columnar cells, and apical constriction then causes them to adopt apically narrow, wedge-like shapes. In addition, the neural plate in Xenopus is stratified, and the non-neural cells in the deep layer (deep cells) pull the overlying superficial cells, eventually bringing the two layers of cells to the midline. Thus, neural tube closure appears to be a complex event in which these three physical events are considered to play key mechanical roles. To test whether these three physical events are mechanically sufficient to drive neural tube formation, we employed a three-dimensional vertex model and used it to simulate the process of neural tube closure. The results suggest that apical constriction cued the bending of the neural plate by pursing the circumference of the apical surface of the neural cells. Neural cell elongation in concert with apical constriction further narrowed the apical surface of the cells and drove the rapid folding of the neural plate, but was insufficient for complete neural tube closure. Migration of the deep cells provided the additional tissue deformation necessary for closure. To validate the model, apical constriction and cell elongation were inhibited in Xenopus laevis embryos. The resulting cell and tissue shapes resembled the corresponding simulation results.

  19. Ex vivo accuracy of three electronic apex locators using different apical file sizes.

    Science.gov (United States)

    Vasconcelos, Bruno Carvalho de; Matos, Leonardo de Alencar; Pinheiro-Júnior, Elilton Cavalcante; Menezes, Antônio Sérgio Teixeira de; Vivacqua-Gomes, Nilton

    2012-01-01

    This study evaluated the accuracy of three electronic apex locators (Root ZX, Novapex, and Justy II) in root canal length determinations using different apical file sizes, considering the apical constriction (AC) and the major foramen (MF) as anatomic references. The diameter of the apical foramina of 40 single-rooted teeth was determined by direct visual measurement and the master apical file was established. Electronic measurements were then performed using 3 instruments: the selected master apical file (adjusted file), one size smaller (intermediate file), and two sizes smaller (misfit file). The distances from the tip of files fixed in the canals to the MF and to the AC were measured digitally. Precision at AC and at MF for the misfit, intermediate and adjusted apical files was as follows: 80%/88%/83% and 78%/83%/95% (Root ZX); 80%/85%/80% and 68%/73%/73% (Novapex); and 78%/80%/78% and 65%/78%/70% (Justy II). Considering the mean discrepancies, statistically significant differences were found only for the adjusted file at MF, with Root ZX presenting the best results at MF. The chi-square test showed significant differences between the acceptable measurements at AC and at MF for the Justy II and Novapex (± 0.5 mm) regardless of file adjustment. Under the conditions of the present study, all devices provided acceptable electronic measurements regardless of file adjustment, except for Root ZX which had its performance improved significantly when the precisely fit apical file was used. Justy II and Novapex provided electronic measurements nearest to the AC.

  20. Intrinsic Ca2+-dependent theta oscillations in apical dendrites of hippocampal CA1 pyramidal cells in vitro.

    Science.gov (United States)

    Hansen, Allan Kjeldsen; Nedergaard, Steen; Andreasen, Mogens

    2014-08-01

    Behavior-associated theta-frequency oscillation in the hippocampal network involves a patterned activation of place cells in the CA1, which can be accounted for by a somatic-dendritic interference model predicting the existence of an intrinsic dendritic oscillator. Here we describe an intrinsic oscillatory mechanism in apical dendrites of in vitro CA1 pyramidal cells, which is induced by suprathreshold depolarization and consists of rhythmic firing of slow spikes in the theta-frequency band. The incidence of slow spiking (29%) increased to 78% and 100% in the presence of the β-adrenergic agonist isoproterenol (2 μM) or 4-aminopyridine (2 mM), respectively. Prior depolarization facilitated the induction of slow spiking. Applied electrical field polarization revealed a distal dendritic origin of slow spikes. The oscillations were largely insensitive to tetrodotoxin, but blocked by nimodipine (10 μM), indicating that they depend on activation of L-type Ca2+ channels. Antagonists of T-, R-, N-, and P/Q-type Ca2+ channels had no detectable effect. The slow spike dimension and frequency was sensitive to 4-aminopyridine (0.1-2 mM) and TEA (10 mM), suggesting the contribution from voltage-dependent K+ channels to the oscillation mechanism. α-Dendrotoxin (10 μM), stromatoxin (2 μM), iberiotoxin (0.2 μM), apamin (0.5 μM), linorpidine (30 μM), and ZD7288 (20 μM) were without effect. Oscillations induced by sine-wave current injection or theta-burst synaptic stimulation were voltage-dependently attenuated by nimodipine, indicating an amplifying function of L-type Ca2+ channels on imposed signals. These results show that the apical dendrites have intrinsic oscillatory properties capable of generating rhythmic voltage fluctuations in the theta-frequency band.

  1. Reguladores vegetais na quebra da dominância apical de mamoeiro (Carica papaya L. Plant growth regulators on breaking apical dominance in papaya plants (Carica papaya L.

    Directory of Open Access Journals (Sweden)

    Elizabeth Orika Ono

    2004-08-01

    Full Text Available O trabalho avaliou os efeitos de reguladores vegetais sobre a quebra da dominância apical de mamoeiro (Carica papaya L. cv. Improved Sunrise Solo. A aplicação dos reguladores vegetais foi iniciada quando as plantas tinham seis meses de idade, totalizando três aplicações, a intervalos de sete dias, constando dos seguintes tratamentos: T1- água (testemunha; T2- GA3 250 mg L-1; T3- GA3 500 mg L-1; T4- benziladenina (BA 250 mg L-1; T5- BA 500 mg L-1; T6- GA3 125 mg L-1 + BA 125 mg L-1; T7- GA3 250 mg L-1 + BA 250 mg L-1. Esses tratamentos foram acompanhados da remoção ou não da gema apical. Os resultados mostraram que plantas tratadas com GA3 + BA a 125 e 250 mg L-1, com e sem a remoção da gema apical, apresentaram maior número de brotações que a testemunha, a qual não apresentou nenhuma brotação das gemas laterais.The objective of this work was to study the effects of gibberelin and cytokinin on breaking apical dominance and axillary buds growth of the Carica papaya L. Papaya plants sprayed three times within a period of 7 days, with the following treatments: T1- water (control, T2- GA3 250 mg L-1, T3- GA3 500 mg L-1, T4- benzyladenine (BA 250 mg L-1, T5- BA 500 mg L-1, T6- GA3 125 mg L-1 + BA 125 mg L-1, T7- GA3 250 mg L-1 + BA 250 mg L-1. The treatments were carried out with or without removal of the apical buds. After 36 days of the last plant growth regulators application was observed lateral bud numbers, lateral buds length and lateral buds diameter. The results showed that there were a higher number of shoots in plants treated with GA3 at 125 mg L-1 + BA at 125 mg L-1 and GA3 at 250mg L-1 + BA at 250 mg L-1. The removal of the apical bud helped the sprouting of the papaya plants.

  2. Revitalization of open apex teeth with apical periodontitis using a collagen-hydroxyapatite scaffold.

    Science.gov (United States)

    Nevins, Alan J; Cymerman, Jerome J

    2015-06-01

    An enhanced revision of the revitalization endodontic technique for immature teeth with apical periodontitis has been described. It includes the addition of collagen-hydroxyapatite scaffold to the currently practiced revascularization technique. Four cases treated in series are presented in this report, 1 case involving 2 teeth. Periapical diagnoses of immature teeth included "asymptomatic apical periodontitis," "symptomatic apical periodontitis," and "acute apical abscess." Additionally, 1 fully developed tooth that had undergone root canal treatment that failed had a periapical diagnosis of acute apical abscess. An established revascularization protocol was used for all teeth. In addition to stimulating blood clots, all teeth were filled with collagen-hydroxyapatite scaffolds. Periapical radiolucencies healed in all teeth, and diffuse radiopacity developed within the coronal portions of canal spaces. Root development with root lengthening occurred in the immature nonvital maxillary premolar that had not undergone prior treatment. The technique of adding a collagen-hydroxyapatite scaffold to the existing revitalization protocol has been described in which substantial hard tissue repair has occurred. This may leave teeth more fully developed and less likely to fracture.

  3. Cholinergic modulation differs between basal and apical dendritic excitation of hippocampal CA1 pyramidal cells.

    Science.gov (United States)

    Leung, L Stan; Péloquin, Pascal

    2010-08-01

    We hypothesize that endogenous cholinergic modulation of dendritic processing of hippocampal CA1 is layer specific, and it specifically enhances spike output resulting from basal as compared with the apical dendritic excitation. Laminar profiles of evoked field potentials were recorded in the CA1 area of urethane-anesthetized rats using multichannel silicon probes and analyzed as current source density. High-frequency stimulation of the pontis oralis (PnO) attenuated the midapical more than the basal or distal apical dendritic excitatory sink. Population spike (PS) and excitatory sink-PS potentiation resulting from basal dendritic excitation were facilitated, while the PS evoked by apical dendritic stimulation was attenuated by PnO stimulation. Perfusion of cholinergic agonist carbachol onto hippocampal slices in vitro also attenuated the apical more than the basal dendritic excitatory postsynaptic potentials. Excitatory sink attenuation and PS changes after PnO stimulation were blocked by systemic or local scopolamine and by intracerebroventricular (icv) M1 receptor antagonist pirenzepine but not by icv M2 receptor antagonist AFDX-116 or nicotinic antagonists. However, a hippocampal theta rhythm activated by PnO stimulation was blocked by systemic but not by local scopolamine. We conclude that endogenous acetylcholine mediates a stronger presynaptic inhibition of the midapical than basal and distal apical excitation mainly through M1 receptors.

  4. Local auxin sources orient the apical-basal axis in Arabidopsis embryos.

    Science.gov (United States)

    Robert, Hélène S; Grones, Peter; Stepanova, Anna N; Robles, Linda M; Lokerse, Annemarie S; Alonso, Jose M; Weijers, Dolf; Friml, Jiří

    2013-12-16

    Establishment of the embryonic axis foreshadows the main body axis of adults both in plants and in animals, but underlying mechanisms are considered distinct. Plants utilize directional, cell-to-cell transport of the growth hormone auxin to generate an asymmetric auxin response that specifies the embryonic apical-basal axis. The auxin flow directionality depends on the polarized subcellular localization of PIN-FORMED (PIN) auxin transporters. It remains unknown which mechanisms and spatial cues guide cell polarization and axis orientation in early embryos. Herein, we provide conceptually novel insights into the formation of embryonic axis in Arabidopsis by identifying a crucial role of localized tryptophan-dependent auxin biosynthesis. Local auxin production at the base of young embryos and the accompanying PIN7-mediated auxin flow toward the proembryo are required for the apical auxin response maximum and the specification of apical embryonic structures. Later in embryogenesis, the precisely timed onset of localized apical auxin biosynthesis mediates PIN1 polarization, basal auxin response maximum, and specification of the root pole. Thus, the tight spatiotemporal control of distinct local auxin sources provides a necessary, non-cell-autonomous trigger for the coordinated cell polarization and subsequent apical-basal axis orientation during embryogenesis and, presumably, also for other polarization events during postembryonic plant life.

  5. In vitro evaluation of Root ZX and Raypex 6 in teeth with different apical diameters

    Directory of Open Access Journals (Sweden)

    Ugur Aydin

    2015-01-01

    Full Text Available Background: There is a growing interest about electronic apex locators for working length determination. There are several studies dealing with their performance in different conditions. Aims: The aim of this study is to evaluate the accuracy of Root ZX and Raypex 6 in teeth with different apical diameters. Materials and Methods: Actual working length (AWL of 80 single rooted teeth were determined as 0.5 mm short of apical foramen. The teeth were divided into 4 groups (n = 20. First group (G 0 included teeth with mature apices. Root canals of the other groups (G 32, G 57 and G 72 were enlarged until apical sizes of 0.32, 0.57 and 0.72 mm were obtained. Samples were embedded in alginate and electronic measurements (EM were performed. Statistical analysis: was achieved with Fisher exact test. Results: Both devices revealed a high rate of success in G 0 and G 32. Their accuracy decreased significantly in G 57 and G 72 groups (P 0.05. Conclusions: Root ZX and Raypex 6 are reliable in teeth with mature apices. At foramen diameters exceeding 0.57 mm, their accuracy is susceptible.

  6. The potassium impermeable apical membrane of insect epithelia: a target for development of safe pesticides

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    William R. Harvey

    1987-01-01

    Full Text Available Columnar cell apical membranes (CCAM in series with goblet cell apical membranes (GCAM form an electroosmotic barrier separating the midgut lumen from epithelial cell cytoplasm. A unique K+ ATPase in GCAM generates three gradients across this barrier. A greater than 180 mV electrical gradient (lumen positive drives amino acid uptake through voltage-dependent K+ symports. A greater than 1000-fold [H+] gradient (lumen alkaline and a greater than 10-fold [K+] gradient (lumen concentrated are adaptations to the high tannin and high K+ content, respectively, in dietary plant material. Agents which act on the apical membrane and disrupt the PD, H+, or K+ gradients are potential insecticides. Insect sensory epithelia and mammalian stria vascularis maintain similar PD and K+ gradients but would not be exposed to ingested anti-apical membrane insecticides. Following the demonstration by Sacchi et al. that Bacillus thuringiensis delta-endotoxin (Bt induces specifically a K+ conductance increase in CCAM vesicles, we find that the K+ channel blocking agent, Ba2+, completely reverses Bt inhibition of the K+-carried short circuit current in the isolated midgut of Manduca sexta. Progress in characterizing the apical membrane includes finding that fluorosulfonylbenzoyladenosine binds specifically to certain GCAM polypeptides and that CCAM vesicles can be mass produced by Ca2+ or Mg2+ precipitation from Manduca sexta midgut.

  7. Midventricular Hypertrophic Cardiomyopathy with Apical Aneurysm: Potential for Underdiagnosis and Value of Multimodality Imaging

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    Archana Sivanandam

    2016-01-01

    Full Text Available We illustrate a case of midventricle obstructive HCM and apical aneurysm diagnosed with appropriate use of multimodality imaging. A 75-year-old African American woman presented with a 3-day history of chest pain and dyspnea with elevated troponins. Her electrocardiogram showed sinus rhythm, left atrial enlargement, left ventricular hypertrophy, prolonged QT, and occasional ectopy. After medical therapy optimization, she underwent coronary angiography for an initial diagnosis of non-ST segment elevation myocardial infarction. Her coronaries were unremarkable for significant disease but her left ventriculogram showed hyperdynamic contractility of the midportion of the ventricle along with a large dyskinetic aneurysmal apical sac. A subsequent transthoracic echocardiogram provided poor visualization of the apical region of the ventricle but contrast enhancement identified an aneurysmal pouch distal to the midventricular obstruction. To further clarify the diagnosis, cardiac magnetic resonance imaging with contrast was performed confirming the diagnosis of midventricular hypertrophic cardiomyopathy with apical aneurysm and fibrosis consistent with apical scar on delayed enhancement. The patient was medically treated and subsequently underwent elective implantable defibrillator placement in the ensuing months for recurrent nonsustained ventricular tachycardia and was initiated on prophylactic oral anticoagulation with warfarin for thromboembolic risk reduction.

  8. The Effect of Smear Layer on Apical Seal of Endodontically Treated Teeth

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    A Farhad

    2004-06-01

    Full Text Available Background: The purpose of this study was to evaluate the effect of smear layer on apical seal of endodontically treated teeth. Methods: Sixty extracted single–rooted human teeth were randomly divided into two experimental groups (n=25 and two control groups (n=5. The teeth were instrumented with K–type files to size 40 and then flared. Apical patency was ensured in all teeth. 5% sodium hypochlorite and 17% Ethylenediamine tetraacetic acid was used as irrigants to remove the smear layer in the second experimental group. The experimental groups were obturated by laterally condensed gutta – percha with Roth 801 sealer. The positive control group was obturated with gutta – percha without sealer. The root surfaces were then coated with nail polish and sticky wax except for the apex in the experimental groups and positive control group. The roots were completely covered in the negative control group. The samples were then immersed in India ink for 1 week at 37°C. Results: The statistical analysis of the results showed that the apical leakage was significantly increased in obturated canals with smear layer. Conclusion: The removal of smear layer might improve the long term apical seal and success of endodontically treated teeth. Keywords: Apical Seal, EDTA, Removal, Sodium Hypochlorite, Smear Layer.

  9. Estudio sobre la adaptación apical de conos maestros de gutapercha en conductos radiculares instrumentados con limas Lightspeed

    OpenAIRE

    Pumarola Suñé, José; García Campaña, Ana M.; Brau Aguadé, Esteban; Canalda Sahli, Carlos

    2000-01-01

    El objetivo de este trabajo fue establecer la coincidencia entre el calibre del cono maestro apical y la lima maestra apical, así como medir cualitativamente la adaptación de diferentes marcas de conos de gutapercha en el tercio apical de conductos radiculares instrumentados con limas Lightspeed. Se instrumentaron 100 conductos de molares naturales extraídos con el sistema Lightspeed. Las muestras se distribuyeron aleatoriamente en cinco grupos. Cada grupo fue obturado mediante condensación l...

  10. Tissue reaction to Endométhasone sealer in root canal fillings short of or beyond the apical foramen

    Directory of Open Access Journals (Sweden)

    Patrícia Suzuki

    2011-10-01

    Full Text Available OBJECTIVE: This study evaluated the response of periapical tissues to the endodontic sealer Endométhasone in root canal fillings short of or beyond the apical foramen. MATERIAL AND METHODS: Twenty root canals of premolars and incisors of 2 mongrel dogs were used. After coronal access and pulp extirpation, the canals were instrumented up to a size 55 K-file and the apical cemental barrier was penetrated with a size 15 K-file to obtain a main apical foramen, which was widened to a size 25 K-file. The canals were irrigated with saline at each change of file. The root canals were obturated either short of or beyond the apical foramen by the lateral condensation of gutta-percha and Endométhasone, originating 2 experimental groups: G1: Endométhasone/short of the apical foramen; G2: Endométhasone/beyond the apical foramen. The animals were killed by anesthetic overdose 90 days after endodontic treatment. The individual roots were obtained and serial histological sections were prepared for histomorphological analysis (H&E and Brown & Brenn techniques under light microscopy. The following parameters were examined: closure of the apical foramen of the main root canal and apical opening of accessory canals, apical cementum resorption, intensity of the inflammatory infiltrate, presence of giant cells and thickness and organization of the apical periodontal ligament. Each parameter was scored 1 to 4, 1 being the best result and 4 the worst. Data were analyzed statistically by the Wilcoxon nonparametric tests (p=0.05. RESULTS: Comparing the 2 groups, the best result (p<0.05 was obtained with root canal filling with Endométhasone short of the apical foramen but a chronic inflammatory infiltrate was present in all specimens. CONCLUSIONS: Limiting the filling material to the root canal space apically is important to determine the best treatment outcome when Endométhasone is used as sealer.

  11. Gibberellin Is Involved in the Regulation of Cell Death-mediated Apical Senescence in G2 Pea

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Senescence is the process of programmed degradation.The G2 line of pea exhibits apical senescence-delaying phenotype under short-day(SD)conditions,but the mechanism regulating the apical senescence is still largely unknown.Gibberellin (GA)was proved to be able to delay this apical senescence phenotype in G2 pea grown under long-day(LD) conditions.Here we show that the initiation of cell death signals in the tarminal floral meristem was involved in the regulation of apical senescence in pea plants.SD signals prevented the formation of the cell death region in the apical mersitem.Moreovsr.GA3 treatment could effectively inhibit the occurrence of cell death-mediated apical senescence in LD-grown apical buds.Therefore,our data suggest that the prevention of apical senescence in SD-grown G2 pea through GA3 treatment may be largely responsible for the regulation of occurrence of the DNA fragmentation in apical meristem.

  12. Depth of planting and apical dominance on cuttings of red pitayaProfundidade de plantio e dominância apical na estaquia de pitaia vermelha

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    Virna Braga Marques

    2012-12-01

    Full Text Available This study was conducted to evaluate the effects of planting depth and breaking apical dominance on cutting of red pitaya Hylocereus undatus (Haw. Britton & Rose. The experiment was conducted in a randomized block design with four replications in a 2x3 factorial, with two kinds of cuttings (with or without apical dominance, cutting not sectioned and sectioned at 5 cm from the upper portion, and three planting depths (1.0, 5.0, and 10.0 cm and each plot consisted of ten 20 cm long cuttings. After 60 days of planting, counts of the number of shoots were began weekly and 90 days after planting survival rooting, number and length of shoots, dry weight of shoots and root dry mass were evaluated. Data were subjected to analysis of variance and polynomial regression at 5% significance level. The percentage of rooting and the survival were 100% in all treatments. With increasing depth of planting it was observed linear reduction in numbers of shoots, dry weight of shoot and root dry mass. The cladodes with apical dominance had longer shoots. The planting of red pitaya cuttings at 1 cm of planting depth with apical dominance is more suited to the production of nursery plants. O trabalho foi conduzido com o objetivo de avaliar os efeitos da profundidade de plantio e da quebra de dominância apical na estaquia de pitaia vermelha Hylocereus undatus (Haw. Britton & Rose. O experimento foi instalado no delineamento em blocos casualizados, com quatro repetições no esquema fatorial 2x3, sendo dois tipos de estacas (com e sem dominância apical, estacas não seccionadas e seccionadas a 5 cm da porção superior, e três profundidades de plantio (1,0; 5,0; 10,0 cm e cada parcela foi constituída de dez estacas com 20 cm de comprimento. Após 60 dias do plantio, foram iniciadas as avaliações semanais do número de brotações e aos 90 dias após o plantio foram avaliados sobrevivência, enraizamento, número e comprimento de brotações, massa seca das brota

  13. Analyses of Interactions Between Heparin and the Apical Surface Proteins of Plasmodium falciparum

    Science.gov (United States)

    Kobayashi, Kyousuke; Takano, Ryo; Takemae, Hitoshi; Sugi, Tatsuki; Ishiwa, Akiko; Gong, Haiyan; Recuenco, Frances C.; Iwanaga, Tatsuya; Horimoto, Taisuke; Akashi, Hiroomi; Kato, Kentaro

    2013-11-01

    Heparin, a sulfated glycoconjugate, reportedly inhibits the blood-stage growth of the malaria parasite Plasmodium falciparum. Elucidation of the inhibitory mechanism is valuable for developing novel invasion-blocking treatments based on heparin. Merozoite surface protein 1 has been reported as a candidate target of heparin; however, to better understand the molecular mechanisms involved, we characterized the molecules that bind to heparin during merozoite invasion. Here, we show that heparin binds only at the apical tip of the merozoite surface and that multiple heparin-binding proteins localize preferentially in the apical organelles. To identify heparin-binding proteins, parasite proteins were fractionated by means of heparin affinity chromatography and subjected to immunoblot analysis with ligand-specific antibodies. All tested members of the Duffy and reticulocyte binding-like families bound to heparin with diverse affinities. These findings suggest that heparin masks the apical surface of merozoites and blocks interaction with the erythrocyte membrane after initial attachment.

  14. Isolated Left Ventricular Apical Hypoplasia with Right Ventricular Outflow Tract Obstruction: A Rare Combination.

    Science.gov (United States)

    Zhao, Yonghui; Zhang, Jiaying; Zhang, Jing

    2015-09-01

    Isolated left ventricular (LV) apical hypoplasia is a unusual and recently recognized congenital cardiac anomaly. A 19-year-old man was found to have an abnormal ECG and cardiac murmur identified during a routine health check since joining work. His ECG revealed normal sinus rhythm, right-axis deviation, poor R wave progression, and T wave abnormalities. On physical examination, a 2/6~3/6 systolic murmur was heard at the second intercostal space along the left sternal border. Subsequent echocardiography and cardiac magnetic resonance imaging confirmed the LV apical hypoplasia. Of note, we first found that LV apical hypoplasia was accompanied by RV outflow tract obstruction due to exaggerated rightward bulging of the basal-anterior septum during systole. A close follow-up was performed for the development of heart failure, pulmonary hypertension, and potentially tachyarrhythmia.

  15. Gibberellin-enhanced elongation of inverted Pharbitis nil shoot prevents the release of apical dominance

    Science.gov (United States)

    Prasad, T. K.; Cline, M. G.

    1987-01-01

    Ethylene evolution resulting from the gravity stress of shoot inversion appears to induce the release of apical dominance in Pharbitis nil (L.) by inhibiting elongation of the inverted shoot. It has been previously demonstrated that this shoot inversion release of apical dominance can be prevented by promoting elongation in the inverted shoot via interference with ethylene synthesis or action. In the present study it was shown that apical dominance release can also be prevented by promoting elongation of the inverted shoot via treatment with gibberellic acid (GA3). A synergistic effect was observed when AgNO3, the ethylene action inhibitor, was applied with GA3. Both GA3 and AgNO3 increased ethylene production in the inverted shoot. These results are consistent with the view that it is ethylene-induced inhibition of elongation and not any direct effect of ethylene per se which is responsible for the outgrowth of the highest lateral bud.

  16. Identification of regions required for apical membrane localization of human multidrug resistance protein 2.

    Science.gov (United States)

    Bandler, Paul E; Westlake, Christopher J; Grant, Caroline E; Cole, Susan P C; Deeley, Roger G

    2008-07-01

    Multidrug resistance proteins MRP1 and MRP2 transport a wide range of endo- and xenobiotics. However, with the exception of certain parts of the brain, MRP1 traffics to basolateral membranes of polarized cells, whereas MRP2 is apical in location and thus it is particularly important for systemic elimination of such compounds. Different regions of MRP1 and MRP2 seem to target them to their respective membrane locations. In addition to two "core" membrane spanning domains (MSDs) characteristic of ATP-binding cassette transporters, MRP1 and MRP2 have a third NH2-terminal MSD (MSD0), which is not required for basolateral targeting of MRP1, or for transport of at least some substrates. Here, we demonstrate that all elements necessary for apical targeting of MRP2 reside in MSD0 and the adjacent cytoplasmic loop (CL) 3. Furthermore, we show that this region of MRP2 can target the core of MRP1 to an exclusively apical location. Within MRP2 CL3, we identified a lysine-rich element that is essential for apical targeting. When introduced into MRP1, this element alone is sufficient to result in partial apical localization. However, exclusive targeting to the apical membrane seems to require the integrity of the entire region encompassing MSD0 and CL3 of MRP2. Because CL3 of MRP1 is critical for binding, transport, or both of several compounds, we also examined the function of hybrids containing all, or portions of MRP2 MSD0 and CL3. Our results indicate that CL3 is important for interaction with both the glutathione and glucuronide conjugates tested, but that different regions may be involved.

  17. Surgical Outcomes and Safety of Robotic Sacrocolpopexy in Women With Apical Pelvic Organ Prolapse

    Science.gov (United States)

    2017-01-01

    Purpose This study aimed to investigate the surgical outcomes and safety of robotic sacrocolpopexy (RSC) in patients with uterine/vaginal vault prolapse. Methods Between January 2009 and June 2015, 16 women with apical prolapse underwent RSC. Pelvic organ prolapse quantification (POP-Q) examination was performed, and treatment success was defined as the presence of grade 0 or I apical prolapse upon POP-Q examination at the final follow-up. Pelvic floor distress inventory-short form 20 (PFDI-SF 20) was administered at every follow-up. A treatment satisfaction questionnaire was administered by telephone to evaluate patient satisfaction with the operation. Results Median age was 65 years (interquartile range [IQR], 56–68 years), and follow-up duration was 25.3 months (IQR, 5.4–34.0 months). Thirteen women (81.3%) had ≥grade III apical prolapse. Operation time was 251 minutes (IQR, 236–288 minutes), and blood loss was 75 mL (IQR, 50–150 mL). Median hospital stay was 4 days (IQR, 3–5 days). At the final follow-up, treatment success was reported in all patients, who presented grade 0 (n=8, 57.1%) and grade I (n=6, 42.9%) apical prolapse. Dramatic improvements in PFDI-SF 20 scores were noted after RSC (from 39 to 4; P=0.001). Most patients (12 of 13) were satisfied with RSC. An intraoperative complication (sacral venous plexus injury) was reported in 1 patient, and there was no conversion to open surgery. Mesh erosion was not reported. Conclusions RSC is an efficient and safe surgical option for apical prolapse repair. Most patients were satisfied with RSC. Thus, RSC might be one of the best treatment options for apical prolapse in women. PMID:28361513

  18. Apical Ballooning Syndrome (Takotsubo Cardiomyopathy after Permanent Dual-Chamber Pacemaker Implantation

    Directory of Open Access Journals (Sweden)

    Armando Gardini

    2012-01-01

    Full Text Available Apical ballooning syndrome, also called takotsubo cardiomyopathy, has been recently reported. It may mimic acute myocardial infarction and is typically observed in postmenopausal women after stressful events. A 75-year-old female after permanent dual chamber pacemaker implant complained of chest pain with repolarization alterations suggesting acute myocardial ischemia. Echocardiography showed a left ventricle with akinesia of the apical portions and reduced global systolic function. The patient was treated with antithrombotic agents and intravenous nitrates. No coronary lesions were found at angiography. At ventriculography, a typical takotsubo-like shape of the left ventricle was observed. The clinical and echocardiographic picture normalized at discharge.

  19. Evolutionary change mimicking apical hypertrophic cardiomyopathy in a patient with takotsubo cardiomyopathy.

    Science.gov (United States)

    Hwang, Hui-Jeong; Lee, Hyae-Min; Yang, In-Ho; Kim, Dong-Hee; Byun, Jong-Kyu; Sohn, Il Suk

    2014-11-01

    In this report, we introduce a case of thickening of the involved left ventricular apical segment on echocardiography and deep T-wave inversions in precordial leads on electrocardiography transiently seen in the course of recovery from biventricular takotsubo cardiomyopathy, mimicking apical hypertrophic cardiomyopathy. This result suggests that the echocardiographic finding of transient myocardial edema can be identified by cardiac magnetic resonance imaging in takotsubo cardiomyopathy. Additionally, it persisted a few weeks after full functional recovery. We believe that this case will contribute in part toward clarifying the pathophysiology of takotsubo cardiomyopathy.

  20. Cone Reconstruction of Atypical Ebstein Anomaly Associated with Right Ventricular Apical Hypoplasia.

    Science.gov (United States)

    Reddin, Gemma; Poterucha, Joseph T; Dearani, Joseph A; Warnes, Carole A; Cetta, Frank

    2016-02-01

    Cone reconstruction for tricuspid valve repair has revolutionized the surgical treatment of Ebstein anomaly. We present the case of a 58-year-old woman with atypical Ebstein anomaly and right ventricular apical hypoplasia who was spared from palliative shunt physiology by our use of cone reconstruction. Compared with other techniques, cone reconstruction of the tricuspid valve more closely replicates normal valvular anatomy and function. This surgical procedure can be applied to many anatomic variations of Ebstein anomaly, as in our patient's apparently unique instance of atypical Ebstein anomaly with right ventricular apical hypoplasia.

  1. Frecuencia de periodontitis apical en tratamientos endodónticos de pregrado

    OpenAIRE

    León, P; Ilabaca,MJ; Alcota,M; González,FE

    2011-01-01

    La periodontitis apical es una enfermedad de los tejidos periapicales de etiología bacteriana. Su tratamiento requiere erradicar los microorganismos del conducto radicular y obturarlo para lograr la reparación posterior. El objetivo de éste trabajo fue determinar la frecuencia de periodontitis apical en la población que asiste a la clínica de Endodoncia de la Facultad de Odontología de la Universidad de Chile y su relación con diferentes variables: diagnóstico específico, edad, sexo, agudas v...

  2. Ecology of the microbiome of the infected root canal system: A comparison between apical and coronal root segments

    NARCIS (Netherlands)

    Özok, A.R.; Persoon, I.F.; Huse, S.M.; Keijser, B.J.F.; Wesselink, P.R.; Crielaard, W.; Zaura, E.

    2012-01-01

    Aim To evaluate the microbial ecology of the coronal and apical segments of infected root canal systems using a complete sampling technique and next-generation sequencing. Methodology The roots of 23 extracted teeth with apical periodontitis were sectioned in half, horizontally, and cryo-pulverized.

  3. A unique approach to demonstrating that apical bud temperature specifically determines leaf initiation rate in the dicot Cucumis sativus

    NARCIS (Netherlands)

    Savvides, Andreas; Dieleman, Anja; Ieperen, van Wim; Marcelis, Leo F.M.

    2016-01-01

    Main conclusion: Leaf initiation rate is largely determined by the apical bud temperature even when apical bud temperature largely deviates from the temperature of other plant organs.We have long known that the rate of leaf initiation (LIR) is highly sensitive to temperature, but previous studies

  4. Formation and removal of apical vapor lock during syringe irrigation : a combined experimental and Computational Fluid Dynamics approach

    NARCIS (Netherlands)

    Boutsioukis, C.; Kastrinakis, E.; Lambrianidis, T.; Verhaagen, B.; Versluis, M.; van der Sluis, L. W. M.

    2014-01-01

    Aim(i) To evaluate the effect of needle type and insertion depth, root canal size and irrigant flow rate on the entrapment of air bubbles in the apical part of a root canal (apical vapor lock) during syringe irrigation using experiments and a Computational Fluid Dynamics (CFD) model, (ii) to investi

  5. Formation and removal of apical vapor lock during syringe irrigation: a combined experimental and Computational Fluid Dynamics approach

    NARCIS (Netherlands)

    Boutsioukis, C.; Kastrinakis, E.; Lambrianidis, T.; Verhaagen, B.; Versluis, M.; Sluis, van der L.W.M.

    2014-01-01

    Aim (i) To evaluate the effect of needle type and insertion depth, root canal size and irrigant flow rate on the entrapment of air bubbles in the apical part of a root canal (apical vapor lock) during syringe irrigation using experiments and a Computational Fluid Dynamics (CFD) model, (ii) to invest

  6. JAM-C is an apical surface marker for neural stem cells.

    Science.gov (United States)

    Stelzer, Sandra; Worlitzer, Maik M A; Bahnassawy, Lamia'a; Hemmer, Kathrin; Rugani, Kirité; Werthschulte, Inga; Schön, Anna-Lena; Brinkmann, Benjamin F; Bunk, Eva C; Palm, Thomas; Ebnet, Klaus; Schwamborn, Jens C

    2012-03-20

    Junctional adhesion molecule-C (JAM-C) is an adhesive cell surface protein expressed in various cell types. JAM-C localizes to the apically localized tight junctions (TJs) between contacting endothelial and epithelial cells, where it contributes to cell-cell adhesions. Just as those epithelial cells, also neural stem cells are highly polarized along their apical-basal axis. The defining feature of all stem cells, including neural stem cells (NSCs) is their ability to self renew. This self-renewal depends on the tight control of symmetric and asymmetric cell divisions. In NSCs, the decision whether a division is symmetric or asymmetric largely depends on the distribution of the apical membrane and cell fate determinants on the basal pole of the cell. In this study we demonstrate that JAM-C is expressed on neural progenitor cells and neural stem cells in the embryonic as well as the adult mouse brain. Furthermore, we demonstrate that in vivo JAM-C shows enrichment at the apical surface and therefore is asymmetrically distributed during cell divisions. These results define JAM-C as a novel surface marker for neural stem cells.

  7. Pulp Revascularization on Permanent Teeth with Open Apices in a Middle-aged Patient.

    Science.gov (United States)

    Wang, Yu; Zhu, Xiaofei; Zhang, Chengfei

    2015-09-01

    Pulp revascularization is a promising procedure for the treatment of adolescents' immature permanent teeth with necrotic pulp and/or apical periodontitis. However, the ability to successfully perform pulp revascularization in a middle-aged patient remains unclear. A 39-year-old woman was referred for treatment of teeth #20 and #29 with necrotic pulp, extensive periapical radiolucencies, and incomplete apices. Pulp revascularization procedures were attempted, including root canal debridement, triple antibiotic paste medication, and platelet-rich plasma transplantation to act as a scaffold. Periapical radiographic and cone-beam computed tomographic examinations were used to review the changes in the apical lesions and root apex configuration. The patient remained asymptomatic throughout the 30-month follow-up. Periapical radiographic examination revealed no change in the apical lesions of either tooth at 8 months. The periapical radiolucency disappeared on tooth #20 and significantly decreased on tooth #29 by the 30-month follow-up, findings that were also confirmed by cone-beam computed tomographic imaging. No evidence of root lengthening or thickening was observed. Successful revascularization was achieved in a middle-aged patient's teeth.

  8. Apical dendrite degeneration, a novel cellular pathology for Betz cells in ALS

    Science.gov (United States)

    Genç, Barış; Jara, Javier H.; Lagrimas, Amiko K. B.; Pytel, Peter; Roos, Raymond P.; Mesulam, M. Marsel; Geula, Changiz; Bigio, Eileen H.; Özdinler, P. Hande

    2017-01-01

    Apical dendrites of Betz cells are important sites for the integration of cortical input, however their health has not been fully assessed in ALS patients. We investigated the primary motor cortices isolated from post-mortem normal control subjects, patients with familial ALS (fALS), sporadic ALS (sALS), ALS with frontotemporal dementia (FTD-ALS), and Alzheimer’s disease (AD), and found profound apical dendrite degeneration of Betz cells in both fALS and sALS, as well as FTD-ALS patients. In contrast, Betz cells of AD patients and normal controls retain cellular integrity in the motor cortex, and CA1 pyramidal neurons show abnormalities predominantly within their soma, rather than the apical dendrite. In line with extensive vacuolation and cytoarchitectural disintegration, the numbers of synapses were also significantly reduced only in ALS patients. Our findings indicate apical dendrite degeneration as a novel cellular pathology that distinguishes ALS and further support the importance of cortical dysfunction for disease pathology. PMID:28165465

  9. USAGE OF PASTE FOR TEMPORARY PLACEMENT IN THE TREATMENT OF CHRONIC APICAL PERIODONTITIS

    Directory of Open Access Journals (Sweden)

    A.V. Borysenko

    2012-03-01

    Full Text Available Summary: The aim of the present investigation was usage of medicamental paste with antibacterial and regeneration action for temporary placement in the treatment of chronic apical periodontitis. Materials and method: The medicamental paste for temporary placement of root canals consists of a mixture of metronidazole, Enterosgel (Silm and Alflutop (Biotehnos S.A., Romania. Thë paste was used for the treatment of 30 teeth with chronic apical periodontitis. Final obturation of the root canals was performed with gutta percha cones and sealer. The efficiency of the treatment was appreciated after examination on the basis of clinical and radiographic findings. Results: During the treatment of the 30 teeth, no exacerbations of the pathological process were recorded. Pain after obturation of the root canals was revealed in only 6 (20% of the treated teeth. No pain, pathologic changes of gingiva, good mastication efficiency in all teeth after treatment were revealed. Conclusions: The high clinical efficiency of the medicamental paste with antibacterial and regeneration action at the level of temporary root canals placement in the treatment of chronic apical periodontitis was shown. Keywords: chronic apical periodontitis, medicamental paste for temporary root canals placement, metronidazole, Enterosgel (Silm and Alflutop (Biotehnos S.A., Romania

  10. Transmission electron microscopy of apical cells of Sphacelaria spp. (Sphacelariales, Phaeophyceae)

    NARCIS (Netherlands)

    Prud’homme van Reine, W.F.; Star, W.

    1981-01-01

    The ultrastructure of apical cells of six species of Sphacelaria (S. arctica, S. cirrosa, S. nana, S. racemosa, S. radicans, and S. rigidula) is studied here. In most details such as ultrastructure of chloroplasts, mitochondria, microbodies, nuclei and centrioles all Sphacelaria species studied are

  11. Assessment of the nonoperated root after apical surgery of the other root in mandibular molars

    DEFF Research Database (Denmark)

    Kraus, Riccardo D; von Arx, Thomas; Gfeller, David

    2015-01-01

    INTRODUCTION: If a surgical approach is chosen to treat a multirooted tooth affected by persistent periapical pathosis, usually only the affected roots are operated on. The present study assessed the periapical status of the nonoperated root 5 years after apical surgery of the other root in mandi...

  12. Micro-CT analyses of apical enlargement and molar root canal complexity

    DEFF Research Database (Denmark)

    Markvart, Merete; Darvann, Tron Andre; Larsen, Per

    2012-01-01

    AIM: To compare the effectiveness of two rotary hybrid instrumentation techniques with focus on apical enlargement in molar teeth and to quantify and visualize spatial details of instrumentation efficacy in root canals of different complexity. METHODOLOGY: Maxillary and mandibular molar teeth wer...

  13. [Use of root-end filling materials in a surgical apical endodontic treatment in the Netherlands

    NARCIS (Netherlands)

    Bronkhorst, M.A.; Berge, S.J.; Damme, P.A. van; Borstlap, W.A.; Merkx, M.A.W.

    2008-01-01

    The material to be used for closing the root canal when carrying out a retrograde surgical apical endodontic treatment continues to be a subject of discussion. The aim of the present study was to inventory which materials are being used for this purpose at this moment by Dutch O&MF surgeons. All pra

  14. Right ventricular outflow and apical pacing comparably worsen the echocardioghraphic normal left ventricle

    NARCIS (Netherlands)

    T.J.F. ten Cate (Tim); M.G. Scheffer (Michael); G.R. Sutherland (George); J.F. Verzijlbergen (Fred); N.M. van Hemel (Norbert)

    2008-01-01

    textabstractAims: A depressed left ventricular function (LVF) is sometimes observed during right ventricular apical (RVA) pacing, but any prediction of this adverse effect cannot be done. Right ventricular outflow tract (RVOT) pacing is thought to deteriorate LVF less frequently because of a more no

  15. Apical root resorption 6 months after initiation of fixed orthodontic appliance therapy.

    NARCIS (Netherlands)

    Smale, I.M.; Artun, J.; Behbehani, F.; Doppel, D.; Hof, M.A. van 't; Kuijpers-Jagtman, A.M.

    2005-01-01

    INTRODUCTION: Individual predisposition might be a major reason for the observed variation in apical orthodontic root resorption. If so, resorption might be expressed during the initial stages of orthodontic therapy in patients at risk. METHODS: To explore this hypothesis, we evaluated standardized,

  16. Ultrasonic root-end preparation in apical surgery : a prospective randomized study

    NARCIS (Netherlands)

    de Lange, Jan; Putters, Thomas; Baas, Erik M.; van Ingen, Johan M.

    2007-01-01

    Objective. The purpose of this study was to evaluate the potential benefit of an ultrasonic device in apical surgery on the outcome of treatment. Study design. A randomized prospective design was used in a standardized treatment protocol. Patients were allocated to treatment with an ultrasonic devic

  17. Anticytokinin effect on apical dominance release in in vitro cultured Rosa hybrida L.

    NARCIS (Netherlands)

    Kapchina-Toteva, V.M.; Somleva, M.; Telgen, van H.J.

    2002-01-01

    Effects of two cytokinin antagonists - 2-chloro-4-cyclobutyl-amino-6-ethylamino-1,3,5-triazine and N-(4-pyridyl)-O-(4-chlorophenyl)carbamate - on bud break and outgrowth in single nodes from two Rosa hybrida cultivars differing in their apical dominance were studied. The compounds were applied at th

  18. Left Ventricular Longitudinal Function Assessed by Speckle Tracking Ultrasound from a Single Apical Imaging Plane

    Directory of Open Access Journals (Sweden)

    Thomas Bagger

    2012-01-01

    Full Text Available Background. Transthoracic ultrasonography of the heart is valuable in monitoring and treatment of critically ill patients. Speckle tracking ultrasound (STU has proven valid in estimating left ventricular systolic deformation. The aims of the study were to compare conventional and automated STU and to determine whether left ventricular systolic deformation could be estimated from one single imaging plane. Methods. 2D-echocardiography cine-loops were obtained from 20 patients for off-line speckle tracking analysis, consisting of manually tracing of the endocardial border (conventional method or automatically drawn boundaries (automated method. Results. We found a bias of 0,6 (95% CI −2.2−3.3 for global peak systolic strain comparing the automated and the conventional method. Comparing global peak systolic strain of apical 4-chamber cine-loops with averaged Global Peak Strain obtained from apical 4, 2 and long axis cine-loops, showed a bias of 0.1 (95% CI −3.9−4.0. The agreement between subcostal 4-chamber and apical 4-chamber global peak systolic strain was 4.4 (95% CI −3.7−12.5. Conclusion. We found good agreement between the conventional and the automated method. STU applied to single apical 4-chamber cine-loops is in excellent agreement with overall averaged global peak systolic strain, while subcostal 4-chamber cine-loops proved less compliant with speckle tracking ultrasound.

  19. SUPPRESSOR OF APICAL DOMINANCE1 of Sporisorium reilianum Modulates Inflorescence Branching Architecture in Maize and Arabidopsis.

    Science.gov (United States)

    Ghareeb, Hassan; Drechsler, Frank; Löfke, Christian; Teichmann, Thomas; Schirawski, Jan

    2015-12-01

    The biotrophic fungus Sporisorium reilianum causes head smut of maize (Zea mays) after systemic plant colonization. Symptoms include the formation of multiple female inflorescences at subapical nodes of the stalk because of loss of apical dominance. By deletion analysis of cluster 19-1, the largest genomic divergence cluster in S. reilianum, we identified a secreted fungal effector responsible for S. reilianum-induced loss of apical dominance, which we named SUPPRESSOR OF APICAL DOMINANCE1 (SAD1). SAD1 transcript levels were highly up-regulated during biotrophic fungal growth in all infected plant tissues. SAD1-green fluorescent protein fusion proteins expressed by recombinant S. reilianum localized to the extracellular hyphal space. Transgenic Arabidopsis (Arabidopsis thaliana)-expressing green fluorescent protein-SAD1 displayed an increased number of secondary rosette-leaf branches. This suggests that SAD1 manipulates inflorescence branching architecture in maize and Arabidopsis through a conserved pathway. Using a yeast (Saccharomyces cerevisiae) two-hybrid library of S. reilianum-infected maize tissues, we identified potential plant interaction partners that had a predicted function in ubiquitination, signaling, and nuclear processes. Presence of SAD1 led to an increase of the transcript levels of the auxin transporter PIN-FORMED1 in the root and a reduction of the branching regulator TEOSINTE BRANCHED1 in the stalk. This indicates a role of SAD1 in regulation of apical dominance by modulation of branching through increasing transcript levels of the auxin transporter PIN1 and derepression of bud outgrowth.

  20. Comparative evaluation of total RNA extraction methods in Theobroma cacao using shoot apical meristems.

    Science.gov (United States)

    Silva, D V; Branco, S M J; Holanda, I S A; Royaert, S; Motamayor, J C; Marelli, J P; Corrêa, R X

    2016-03-04

    Theobroma cacao is a species of great economic importance with its beans used for chocolate production. The tree has been a target of various molecular studies. It contains many polyphenols, which complicate the extraction of nucleic acids with the extraction protocols requiring a large amount of plant material. These issues, therefore, necessitate the optimization of the protocols. The aim of the present study was to evaluate different methods for extraction of total RNA from shoot apical meristems of T. cacao 'CCN 51' and to assess the influence of storage conditions for the meristems on the extraction. The study also aimed to identify the most efficient protocol for RNA extraction using a small amount of plant material. Four different protocols were evaluated for RNA extraction using one shoot apical meristem per sample. Among these protocols, one that was more efficient was then tested to extract RNA using four different numbers of shoot apical meristems, subjected to three different storage conditions. The best protocol was tested for cDNA amplification using reverse transcription-polymerase chain reaction; the cDNA quality was determined to be satisfactory for molecular analyses. The study revealed that with the best RNA extraction protocol, one shoot apical meristem was sufficient for extraction of high-quality total RNA. The results obtained might enable advances in genetic analyses and molecular studies using reduced amount of plant material.

  1. Morphology of the Physiological Apical Foramen in Maxillary and Mandibular First Molars

    Science.gov (United States)

    Abarca, J.; Zaror, C.; Monardes, H.; Hermosilla, V.; Muñoz, C.; Cantin, M.

    2015-01-01

    SUMMARY Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3–5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24–0.33 mm in maxillary first molars and between 0.25–0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully. PMID:25937698

  2. Antimicrobial susceptibility profiles of bacterial strains isolated from chronic apical periodontitis

    Directory of Open Access Journals (Sweden)

    Luminita Marutescu

    2013-12-01

    Full Text Available The aim of the present study is to investigate the microbiota of root filled teeth with apical periodontitis and to determine the antibiotic susceptibility patterns of microbial strains isolated from twenty nine apical lesion samples taken from patients with fibrous chronic apical lesions. The present study has highlighted the polymicrobial nature of the root canal infections and the importance of facultatively anaerobic, Gram positive bacteria found in 90.74% of the isolated microorganims. The present study has shown an increased resistance of microorganisms to conventional antibiotics, which included penicillin, erythromycin and amoxicillin, as well as tetracyclines, although the last ones have been used sparingly in the past decade. The results of antibiotic sensitivity obtained in this study underline the importance of the microbiological diagnosis and antibiotic susceptibility testing in the choice of therapeutic agents used for the treatment of chronic apical lesions. Further studies with clinical correlation of effectiveness of these antibiotics and cultures taken after administration of antibiotics as well as recording of disappearance of symptoms are also recommended.

  3. Responses of Metabolites in Soybean Shoot Apices to Changing Atmospheric Carbon Dioxide Concentrations

    Directory of Open Access Journals (Sweden)

    Richard Sicher

    2012-01-01

    Full Text Available Soybean seedlings were grown in controlled environment chambers with CO2 partial pressures of 38 (ambient and 72 (elevated Pa. Five or six shoot apices were harvested from individual 21- to 24-day-old plants. Metabolites were analyzed by gas chromatography and, out of 21 compounds, only sucrose and fructose increased in response to CO2 enrichment. One unidentified metabolite, Unk-21.03 decreased up to 80% in soybean apices in response to elevated CO2. Levels of Unk-21.03 decreased progressively when atmospheric CO2 partial pressures were increased from 26 to 100 Pa. Reciprocal transfer experiments showed that Unk-21.03, and sucrose in soybean apices were altered slowly over several days to changes in atmospheric CO2 partial pressures. The mass spectrum of Unk-21.03 indicated that this compound likely contained both an amino and carboxyl group and was structurally related to serine and aspartate. Our findings suggested that CO2 enrichment altered a small number of specific metabolites in soybean apices. This could be an important step in understanding how plant growth and development are affected by carbon dioxide enrichment.

  4. Limited elimination of two viruses by cryotherapy of pelargonium apices related to virus distribution.

    Science.gov (United States)

    Gallard, A; Mallet, R; Chevalier, M; Grapin, A

    2011-01-01

    The possibility of eradicating the pelargonium flower break virus (PFBV) and pelargonium line pattern virus (PLPV) by cryotherapy of axillary shoot apices was investigated using five Pelargonium cultivars. Viruses were detected by DAS-ELISA and their location was determined by immunolocalization. Apex culture did not permit elimination of PFBV and only 15 percent regenerated plants of 'Stellar Artic' cultivar were ELISA PLPV-negative. Plants regenerated from cryotherapy-treated apices were tested by DAS-ELISA after a 3-month in vitro culture period. Viruses were not detected in 25 percent and 50 percent of the plants tested for PFBV and PLPV, respectively. However, immunolocalization carried out on apices originating from cryopreserved shoot tips sampled from DAS-ELISA negative plants showed that they were still virus-infected. Using immunolocalization, PFBV and PLPV could be detected in Pelargonium apices, even in the meristematic dome. However, viral particles were more numerous in basal zone cells than in meristematic cells. Our results demonstrate that PFBV and PLPV are present within meristematic cells and that cryopreservation can partly reduce the quantity of these viruses in Pelargonium plants but not eliminate them totally. Additional knowledge on localization and behaviour of viruses during cryopreservation is essential to optimize cryotherapy and plant genetic resource management.

  5. Pulp Revascularization in Immature Permanent Tooth with Apical Periodontitis Using Mineral Trioxide Aggregate

    Directory of Open Access Journals (Sweden)

    Katsura Saeki

    2014-01-01

    Full Text Available Mineral trioxide aggregate (MTA is a material that has been used worldwide in several clinical applications, such as apical barriers in teeth with immature apices, repair of root perforations, root-end filling, pulp capping, and pulpotomy. The purpose of this case report was to describe successful revascularization treatment of an immature mandibular right second premolar with apical periodontitis in a 9-year-old female patient. After preparing an access cavity without anesthesia, the tooth was isolated using a rubber dam and accessed. The canal was gently debrided using 5% sodium hypochlorite (NaOCl and 3% hydrogen peroxide irrigant. And then MTA was packed into the canal. X-ray photographic examination showed the dentin bridge 5 months after the revascularization procedure. Thickening of the canal wall and complete apical closure were confirmed 10 months after the treatment. In this case, MTA showed clinical and radiographic success at revascularization treatment in immature permanent tooth. The successful outcome of this case suggests that MTA is reliable and effective for endodontic treatment in the pediatric dentistry.

  6. Cone beam computed tomography study of apical root resorption induced by Herbst appliance

    Science.gov (United States)

    SCHWARTZ, João Paulo; RAVELI, Taísa Boamorte; ALMEIDA, Kélei Cristina de Mathias; SCHWARTZ-FILHO, Humberto Osvaldo; RAVELI, Dirceu Barnabé

    2015-01-01

    Objective This study evaluated the frequency of root resorption during the orthodontic treatment with Herbst appliance by Cone Beam Computed Tomography (CBCT). Material and Methods The sample comprised 23 patients (11 men, 12 women; mean ages 15.76±1.75 years) with Class II division 1 malocclusion, treated with Herbst appliance. CBCT was obtained before treatment (T0) and after Herbst treatment (T1). All the dental roots, except third molars, were evaluated, and apical root resorption was determined using the axial guided navigation method. Paired t-tests and Wilcoxon T Test were used to compare the dependent samples in parametric and nonparametric cases, respectively. Chi-Square Test with Yates’ correction was used to evaluate the relationship between apical root resorption and gender. Results were considered at a significance level of 5%. Results Apical resorption was detected by CBCT in 57.96% of 980 roots that underwent Herbst appliance treatment. All patients had minimal resorption and there was no statistical significance between the genders. Conclusion CBCT three-dimensional evaluation showed association between Herbst appliance and minimal apical root resorption, mostly in the anchoring teeth, without clinical significance. PMID:26537718

  7. The Effect of Calcium Hydroxide As an Intracanal Medication of The Apical Microleakage

    Directory of Open Access Journals (Sweden)

    Heshmat Mohajer AR

    2011-12-01

    Full Text Available Background and Aims: Nowadays, calcium hydroxide is used as a dressing for canal sterilization and repair progression of apical lesions. The aim of this study was to investigate the effect of calcium hydroxide as an intracanal medicament on the apical microleakage of root filling.Materials and Methods: In this experimental study, 46 extracted single-rooted human teeth were instrumented with step-back technique to master apical file (MAF size 35. Specimens were randomly divided into 2 groups (n = 20. In group 1, the specimens were treated with calcium hydroxide intracanal medication; and in group 2, the samples did not receive any medication. The teeth were incubated in 100% humidity at 37°C for one week. After that, calcium hydroxide was removed using irrigation with normal saline and reaming with MAF. The root canals were obturated with gutta- percha and AH26 sealer using lateral compaction technique. Specimens were incubated in 100% humility at 37°C for 72 hours and then immersed in India ink for 1 week. Finally, the teeth were cleared and the maximum linear dye penetration was measured under a stereomicroscope at 4X magnification. The data were analyzed by T-test and Chi-square.Results: There was no significant difference between the two experimental groups (P=0.068. Conclusion: The findings of this study indicated that using calcium hydroxide as an intracanal medicament did not influence the apical microleakage after final obturation of the root canal system.

  8. Apical Dominance and Planting Density Effects on Weed Suppression by Sunn Hemp (Crotalaria juncea L.)

    Science.gov (United States)

    A field study was conducted in 2008 and 2009 in Citra, Florida to evaluate the effects of seeding rate and removal of apical dominance of sunn hemp (Crotalaria juncea L.) on weed suppression and seed production of sunn hemp. Three seeding rates of sunn hemp were used; a representative seed producti...

  9. Uncovering labially impacted teeth: apically positioned flap and closed-eruption techniques.

    Science.gov (United States)

    Vermette, M E; Kokich, V G; Kennedy, D B

    1995-01-01

    The purpose of this study was to examine the esthetic and periodontal differences between two methods of uncovering labially impacted maxillary anterior teeth: the apically positioned flap and closed-eruption techniques. The sample consisted of 30 patients who were recalled a minimum of three months after orthodontic treatment of a unilateral labially impacted maxillary anterior tooth. Eighteen of the patients had undergone an apically positioned flap (APF) procedure, and the remaining twelve had undergone the closed-eruption (CE) technique. In the CE group, clinical examination showed less width of attached gingiva on the distal surface and increased probing bone level on the facial surface of the uncovered teeth relative to their contralateral controls. Uncovered teeth in the APF group showed more apical gingival margins on the mesial and facial surfaces; greater crown length on the midfacial surface; increased probing attachment level on the facial surface; increased width of attached gingiva on the facial surface; increased probing bone level on mesial, facial, and distal surfaces; and gingival scarring. Radiographic examination showed shorter roots on the uncovered teeth in both groups. Photographic examination revealed vertical relapse of the uncovered teeth in the APF group. We conclude that labially impacted maxillary anterior teeth uncovered with an apically positioned flap technique have more unesthetic sequalae than those uncovered with a closed-eruption technique.

  10. Viable bacteria in root dentinal tubules of teeth with apical periodontitis

    NARCIS (Netherlands)

    Peters, LB; Wesselink, P.R.; Buijs, JF; van Winkelhoff, AJ

    2001-01-01

    Two sets of teeth with apical periodontitis were collected at different geographic locations to study the identity of bacteria left in the root dentinal tubules. Root dentin of 20 of these teeth was cultured from three locations between pulp and cementum (A, B, and C). In addition dentin from eight

  11. Comparison of apical leakage between immediate versus delayed post space preparation using two resin sealers

    Directory of Open Access Journals (Sweden)

    Priyanka Kaushal Kalra

    2009-01-01

    Full Text Available Post & Core Procedures have became an integral part of a dentist′s arsenal. This study was carried out in order to assess the microleakage when immediate and delayed post space preparations were done using resin sealers. Immediate post space preparations showed lesser apical leakage as opposed to delayed post space preparation.

  12. Feasibility of transapical aortic valve replacement through a left ventricular apical diverticulum

    Directory of Open Access Journals (Sweden)

    Ferrari Enrico

    2013-01-01

    Full Text Available Abstract Transapical aortic valve replacement is an established technique performed in high-risk patients with symptomatic aortic valve stenosis and vascular disease contraindicating trans-vascular and trans-aortic procedures. The presence of a left ventricular apical diverticulum is a rare event and the treatment depends on dimensions and estimated risk of embolisation, rupture, or onset of ventricular arrhythmias. The diagnosis is based on standard cardiac imaging and symptoms are very rare. In this case report we illustrate our experience with a 81 years old female patient suffering from symptomatic aortic valve stenosis, respiratory disease, chronic renal failure and severe peripheral vascular disease (logistic euroscore: 42%, who successfully underwent a transapical 23 mm balloon-expandable stent-valve implantation through an apical diverticulum of the left ventricle. Intra-luminal thrombi were absent and during the same procedure were able to treat the valve disease and to successfully exclude the apical diverticulum without complications and through a mini thoracotomy. To the best of our knowledge, this is the first time that a transapical procedure is successfully performed through an apical diverticulum.

  13. Cone beam computed tomography study of apical root resorption induced by Herbst appliance

    Directory of Open Access Journals (Sweden)

    João Paulo SCHWARTZ

    2015-10-01

    Full Text Available Objective This study evaluated the frequency of root resorption during the orthodontic treatment with Herbst appliance by Cone Beam Computed Tomography (CBCT.Material and Methods The sample comprised 23 patients (11 men, 12 women; mean ages 15.76±1.75 years with Class II division 1 malocclusion, treated with Herbst appliance. CBCT was obtained before treatment (T0 and after Herbst treatment (T1. All the dental roots, except third molars, were evaluated, and apical root resorption was determined using the axial guided navigation method. Paired t-tests and Wilcoxon T Test were used to compare the dependent samples in parametric and nonparametric cases, respectively. Chi-Square Test with Yates’ correction was used to evaluate the relationship between apical root resorption and gender. Results were considered at a significance level of 5%.Results Apical resorption was detected by CBCT in 57.96% of 980 roots that underwent Herbst appliance treatment. All patients had minimal resorption and there was no statistical significance between the genders.Conclusion CBCT three-dimensional evaluation showed association between Herbst appliance and minimal apical root resorption, mostly in the anchoring teeth, without clinical significance.

  14. A laboratory assessment of bacterial leakage in MTA apical plugs exposed to phosphate-buffered saline.

    Science.gov (United States)

    de Almeida, Josiane; Pimenta, Andrea L; Felippe, Wilson T

    2015-01-01

    This study evaluated the influence of the exposure of mineral trioxide aggregate (MTA) - with and without calcium chloride (CaCl2) -to phosphate-buffered saline (PBS) on apical microleakage. Sixty root segments were divided into 4 experimental groups (n=15). Apical cavities were filled with MTA with or without CaCl2, and the root canals dressed with a moistened cotton pellet or PBS: 1) MTA/cotton pellet; 2) MTA/PBS; 3) MTA+ 10%CaCl2/cotton pellet; 4) MTA+10%CaCl2/PBS. After 2 months, E. faecalis penetration was analyzed along the apical plugs. Samples were observed weekly for 70 days, and leakage was detected by turbidity of the medium in contact with the root segment. Teeth in the control groups (n=2) were either made completely impermeable or kept without an apical plug. The Kaplan-Meier method was used to analyze survival and the Logrank test was used to compare the survival curves (pMTA sealing ability, but cannot prevent bacterial leakage. The addition of CaCl2 to the MTA did not improve MTA sealing ability.

  15. Differentiation of apical and basal dendrites in pyramidal cells and granule cells in dissociated hippocampal cultures.

    Science.gov (United States)

    Wu, You Kure; Fujishima, Kazuto; Kengaku, Mineko

    2015-01-01

    Hippocampal pyramidal cells and dentate granule cells develop morphologically distinct dendritic arbors, yet also share some common features. Both cell types form a long apical dendrite which extends from the apex of the cell soma, while short basal dendrites are developed only in pyramidal cells. Using quantitative morphometric analyses of mouse hippocampal cultures, we evaluated the differences in dendritic arborization patterns between pyramidal and granule cells. Furthermore, we observed and described the final apical dendrite determination during dendritic polarization by time-lapse imaging. Pyramidal and granule cells in culture exhibited similar dendritic patterns with a single principal dendrite and several minor dendrites so that the cell types were not readily distinguished by appearance. While basal dendrites in granule cells are normally degraded by adulthood in vivo, cultured granule cells retained their minor dendrites. Asymmetric growth of a single principal dendrite harboring the Golgi was observed in both cell types soon after the onset of dendritic growth. Time-lapse imaging revealed that up until the second week in culture, final principal dendrite designation was not stabilized, but was frequently replaced by other minor dendrites. Before dendritic polarity was stabilized, the Golgi moved dynamically within the soma and was repeatedly repositioned at newly emerging principal dendrites. Our results suggest that polarized growth of the apical dendrite is regulated by cell intrinsic programs, while regression of basal dendrites requires cue(s) from the extracellular environment in the dentate gyrus. The apical dendrite designation is determined from among multiple growing dendrites of young developing neurons.

  16. A systematic analysis of neonatal mouse heart regeneration after apical resection.

    Science.gov (United States)

    Bryant, Donald Marion; O'Meara, Caitlin Claire; Ho, Nhi Ngoc; Gannon, Joseph; Cai, Lei; Lee, Richard Theodore

    2015-02-01

    The finding that neonatal mice are able to regenerate myocardium after apical resection has recently been questioned. We determined if heart regeneration is influenced by the size of cardiac resection and whether surgical retraction of the ventricular apex results in an increase in cardiomyocyte cell cycle activity. We performed moderate or large apical ventricular resections on neonatal mice and quantified scar infiltration into the left ventricular wall at 21 days post-surgery. Moderately resected hearts had 15±2% of the wall infiltrated by a collagen scar; significantly greater scar infiltration (23±4%) was observed in hearts with large resections. Resected hearts had higher levels of cardiomyocyte cell cycle activity relative to sham hearts. Surgically retracting the ventricle often resulted in fibrosis and induced cardiomyocyte cell cycle activity that were comparable to that of resected hearts. We conclude that apical resection in neonatal mice induces cardiomyocyte cell cycle activity and neomyogenesis, although scarring can occur. Surgical technique and definition of approach to assessing the extent of regeneration are both critical when using the neonatal mouse apical resection model.

  17. Sugar demand, not auxin, is the initial regulator of apical dominance.

    Science.gov (United States)

    Mason, Michael G; Ross, John J; Babst, Benjamin A; Wienclaw, Brittany N; Beveridge, Christine A

    2014-04-22

    For almost a century the plant hormone auxin has been central to theories on apical dominance, whereby the growing shoot tip suppresses the growth of the axillary buds below. According to the classic model, the auxin indole-3-acetic acid is produced in the shoot tip and transported down the stem, where it inhibits bud growth. We report here that the initiation of bud growth after shoot tip loss cannot be dependent on apical auxin supply because we observe bud release up to 24 h before changes in auxin content in the adjacent stem. After the loss of the shoot tip, sugars are rapidly redistributed over large distances and accumulate in axillary buds within a timeframe that correlates with bud release. Moreover, artificially increasing sucrose levels in plants represses the expression of BRANCHED1 (BRC1), the key transcriptional regulator responsible for maintaining bud dormancy, and results in rapid bud release. An enhancement in sugar supply is both necessary and sufficient for suppressed buds to be released from apical dominance. Our data support a theory of apical dominance whereby the shoot tip's strong demand for sugars inhibits axillary bud outgrowth by limiting the amount of sugar translocated to those buds.

  18. Deep-apical tubules: dynamic lipid-raft microdomains in the brush-border region of enterocytes

    DEFF Research Database (Denmark)

    Hansen, Gert H; Pedersen, Jens; Niels-Christiansen, Lise-Lotte

    2003-01-01

    microdomains. Deep-apical tubules were positioned close to the actin rootlets of adjacent microvilli in the terminal web region, which had a diameter of 50-100 nm, and penetrated up to 1 microm into the cytoplasm. Markers for transcytosis, IgA and the polymeric immunoglobulin receptor, as well as the resident...... lipid raft-containing compartments, but little is otherwise known about these raft microdomains. We therefore studied in closer detail apical lipid-raft compartments in enterocytes by immunogold electron microscopy and biochemical analyses. Novel membrane structures, deep-apical tubules, were visualized...... brush-border enzyme aminopeptidase N, were present in these deep-apical tubules. We propose that deep-apical tubules are a specialized lipid-raft microdomain in the brush-border region functioning as a hub in membrane trafficking at the brush border. In addition, the sensitivity to cholesterol depletion...

  19. Morphology of bacterial flora in root canals associated with apical abscesses

    Institute of Scientific and Technical Information of China (English)

    Guo Huijie; Gao Chengzhi; Zhang Chengfei; Zheng Shuying; Yue Lin

    2014-01-01

    Background Apical abscess is an inflammatory process in the peri-radicular tissues caused by biofllms in the necrotic root canal systems.Therefore,a comprehensive analysis of the bacterial colonization is required for a better understanding of the pathogenesis.This study aimed to investigate the patterns of bacterial infection of root canals of teeth with apical abscesses and to determine whether histological and microbiological findings correlated with clinical conditions.Methods Eighteen samples from 18 teeth with apical pathological lesions were analyzed.Nine patients with acute apical abscesses experienced severe pain,and nine patients were asymptomatic with a sinus tract.After extraction,each affected root was divided into two halves.One half was processed for histobacteriologic analysis and examined using light microscopy,and the other half was analyzed using scanning electron microscopy (SEM) to determine the patterns of microbial colonization of the root canals.Results The appearance of each sample subjected to SEM was consistent with the histobacteriologic findings despite the presence or absence of clinical symptoms.Intraradicular biofilms comprising cocci,rods,and/or filaments of amorphous materials were observed in the apical third of the main root canals in all samples.The bacterial biofilms covering the main root canal walls also penetrated the dentinal tubules to varying depths.The morphologies of biofilms varied,and a unique pattern of intraradicular infection was not identified.Conclusion Intraradicular infections formed complex and variable multispecies biofilms and their presence did not correlate with clinical symptoms.

  20. Apical crown technique to model canal roots. A review of the literature.

    Science.gov (United States)

    Tortini, D; Colombo, M; Gagliani, M

    2007-09-01

    The goals of endodontic therapy are to shape and clean the root canal system in order to receive a three-dimensional and hermetic filling of the entire endodontic space. The aim of this review is to analyze the development of the different canal shaping techniques from the manual stainless-steel instruments to the recently developed rotary Ni-Ti systems. The need to provide instruments of a suitable size to reach the apex of curved root canals drove the development of preparation techniques with a greater focus on the apical part. The Crown-Down technique involves the widening of the canal orifices with Gates-Glidden drills followed by the incremental removal of organic canal contents proceeding from the canal orifice to the apical portion using manual files. Files are used from larger to smaller with no apical pressure. Nevertheless, the term ''Crown-Down'' does not define the technique in the strictest sense, nor does it provide a specific sequence for the use of instruments, but rather defines a way to use the instruments. The preparation of root canals has been revolutionised by the development of Ni-Ti alloys. The features of this alloy give instruments profound flexibility and allow the manufacture of more tapered instruments compared with traditional stainless-steel instruments. In the second part of this review, numerous examples are provided concerning the comparison between different Ni-Ti systems and their techniques for use. A Crown-Down approach provides certain advantages including early organic debris removal, the creation of a large reservoir for irrigating solutions, a straighter access to the apical region of curved canals, and greater precision with regard to the exact working length and apical size.

  1. CASE OF DIAGNOSIS OF APICAL FORM OF HYPERTROPHIC CARDIOMYOPATHY WITH A PATIENT WITH PROGRESSIVE ANGINA CLINIC

    Directory of Open Access Journals (Sweden)

    N. S. Krylova

    2015-01-01

    Full Text Available Objective of work: to describe the apical form of hypertrophic cardiomyopathy (AFHC developing under the "mask" of the ischemic heart disease not diagnosed for a long period.Materials and methods. Patient B., 73 y.o., female, was brought to the cardiology department with complains of severe pressing pain behind the breastbone caused with no apparent reason and lasting for over 4 hours. The following examination of the patient was performed: electrocardiography (ECG, echocardiography (EchoCG, Holter ECG monitoring, coronary angiography (CAG, ventriculography.Results. The final diagnosis for the patient was set on the basis of the following readings: ECG data (basic rhythm – atrial fibrillation, left ventricle (LV hypertrophy, negative T-waves in leads V1–6, ST segment depression up to 1–2 mm in leads V4–6, EchoCG (hypertrophy of apical segments of the LV with decreasing of its cavity, moderate dilatation of the left atrium, intraventricular obstruction in the apical third of the LV with the maximum pressure gradient of up to 48 mm Hg., CAG (stenotic lesions of coronary arteries were found, ventriculography (LV volume is not increased, no violations of local contractility, narrowing of the LV cavity in the lower third is observed with thinning in the apex, which indicatesexpressed apical hypertrophy of the LV myocard. AFHC, apical form with moderate obstruction in the lower third of the left ventricle. Stress angina syndrome. CAG and ventriculography were main diagnostic methods that allowed setting the final diagnosis.Conclusion. The clinical case sets forth the peculiarities of diagnostics, therapy, and post-therapy management of patients with this form of AFHC.

  2. Wizard CD Plus and ProTaper Universal: analysis of apical transportation using new software

    Directory of Open Access Journals (Sweden)

    Daiana Giannastasio

    2013-09-01

    Full Text Available OBJECTIVE: This study has two aims: 1 to evaluate the apical transportation of the Wizard CD Plus and ProTaper Universal after preparation of simulated root canals; 2 to compare, with Adobe Photoshop, the ability of a new software (Regeemy in superposing and subtracting images. MATERIAL AND METHODS: Twenty five simulated root canals in acrylic-resin blocks (with 20º curvature underwent cone beam computed tomography before and after preparation with the rotary systems (70 kVp, 4 mA, 10 s and with the 8×8 cm FoV selection. Canals were prepared up to F2 (ProTaper and 24.04 (Wizard CD Plus instruments and the working length was established to 15 mm. The tomographic images were imported into iCAT Vision software and CorelDraw for standardization. The superposition of pre- and post-instrumentation images from both systems was performed using Regeemy and Adobe Photoshop. The apical transportation was measured in millimetres using Image J. Five acrylic resin blocks were used to validate the superposition achieved by the software. Student's t-test for independent samples was used to evaluate the apical transportation achieved by the rotary systems using each software individually. Student's t-test for paired samples was used to compare the ability of each software in superposing and subtracting images from one rotary system per time. RESULTS: The values obtained with Regeemy and Adobe Photoshop were similar to rotary systems (P>0.05. ProTaper Universal and Wizard CD Plus promoted similar apical transportation regardless of the software used for image's superposition and subtraction (P>0.05. CONCLUSION: Wizard CD Plus and ProTaper Universal promoted little apical transportation. Regeemy consists in a feasible software to superpose and subtract images and appears to be an alternative to Adobe Photoshop.

  3. Comparative larval myogenesis and adult myoanatomy of the rhynchonelliform (articulate) brachiopods Argyrotheca cordata, A. cistellula, and Terebratalia transversa

    DEFF Research Database (Denmark)

    Altenburger, Andreas; Wanninger, Andreas

    2009-01-01

    transversa using fluorescence F-actin labelling combined with confocal laserscanning microscopy. RESULTS: Fully grown larvae of A. cordata and T. transversa consist of three distinct body regions, namely an apical lobe, a mantle lobe with four bundles of setae, and a pedicle lobe. Myogenesis is very similar...... in these two species. The first anlagen of the musculature develop in the pedicle lobe, followed by setae muscles and the mantle lobe musculature. Late-stage larvae show a network of strong pedicle muscles, central mantle muscles, longitudinal muscles running from the mantle to the pedicle lobe, setae pouch...... muscles, setae muscles, a U-shaped muscle, serial mantle muscles, and apical longitudinal as well as apical transversal muscles. Fully developed A. cistellula larvae differ from the former species in that they have only two visible body lobes and lack setae. Nevertheless, we found corresponding muscle...

  4. Transcriptome profiling of low temperature-treated cassava apical shoots showed dynamic responses of tropical plant to cold stress

    Directory of Open Access Journals (Sweden)

    An Dong

    2012-02-01

    Full Text Available Abstract Background Cassava is an important tropical root crop adapted to a wide range of environmental stimuli such as drought and acid soils. Nevertheless, it is an extremely cold-sensitive tropical species. Thus far, there is limited information about gene regulation and signalling pathways related to the cold stress response in cassava. The development of microarray technology has accelerated the study of global transcription profiling under certain conditions. Results A 60-mer oligonucleotide microarray representing 20,840 genes was used to perform transcriptome profiling in apical shoots of cassava subjected to cold at 7°C for 0, 4 and 9 h. A total of 508 transcripts were identified as early cold-responsive genes in which 319 sequences had functional descriptions when aligned with Arabidopsis proteins. Gene ontology annotation analysis identified many cold-relevant categories, including 'Response to abiotic and biotic stimulus', 'Response to stress', 'Transcription factor activity', and 'Chloroplast'. Various stress-associated genes with a wide range of biological functions were found, such as signal transduction components (e.g., MAP kinase 4, transcription factors (TFs, e.g., RAP2.11, and reactive oxygen species (ROS scavenging enzymes (e.g., catalase 2, as well as photosynthesis-related genes (e.g., PsaL. Seventeen major TF families including many well-studied members (e.g., AP2-EREBP were also involved in the early response to cold stress. Meanwhile, KEGG pathway analysis uncovered many important pathways, such as 'Plant hormone signal transduction' and 'Starch and sucrose metabolism'. Furthermore, the expression changes of 32 genes under cold and other abiotic stress conditions were validated by real-time RT-PCR. Importantly, most of the tested stress-responsive genes were primarily expressed in mature leaves, stem cambia, and fibrous roots rather than apical buds and young leaves. As a response to cold stress in cassava, an increase

  5. Adenovirus entry from the apical surface of polarized epithelia is facilitated by the host innate immune response.

    Science.gov (United States)

    Kotha, Poornima L N; Sharma, Priyanka; Kolawole, Abimbola O; Yan, Ran; Alghamri, Mahmoud S; Brockman, Trisha L; Gomez-Cambronero, Julian; Excoffon, Katherine J D A

    2015-03-01

    Prevention of viral-induced respiratory disease begins with an understanding of the factors that increase or decrease susceptibility to viral infection. The primary receptor for most adenoviruses is the coxsackievirus and adenovirus receptor (CAR), a cell-cell adhesion protein normally localized at the basolateral surface of polarized epithelia and involved in neutrophil transepithelial migration. Recently, an alternate isoform of CAR, CAREx8, has been identified at the apical surface of polarized airway epithelia and is implicated in viral infection from the apical surface. We hypothesized that the endogenous role of CAREx8 may be to facilitate host innate immunity. We show that IL-8, a proinflammatory cytokine and a neutrophil chemoattractant, stimulates the protein expression and apical localization of CAREx8 via activation of AKT/S6K and inhibition of GSK3β. Apical CAREx8 tethers infiltrating neutrophils at the apical surface of a polarized epithelium. Moreover, neutrophils present on the apical-epithelial surface enhance adenovirus entry into the epithelium. These findings suggest that adenovirus evolved to co-opt an innate immune response pathway that stimulates the expression of its primary receptor, apical CAREx8, to allow the initial infection the intact epithelium. In addition, CAREx8 is a new target for the development of novel therapeutics for both respiratory inflammatory disease and adenoviral infection.

  6. Adenovirus entry from the apical surface of polarized epithelia is facilitated by the host innate immune response.

    Directory of Open Access Journals (Sweden)

    Poornima L N Kotha

    2015-03-01

    Full Text Available Prevention of viral-induced respiratory disease begins with an understanding of the factors that increase or decrease susceptibility to viral infection. The primary receptor for most adenoviruses is the coxsackievirus and adenovirus receptor (CAR, a cell-cell adhesion protein normally localized at the basolateral surface of polarized epithelia and involved in neutrophil transepithelial migration. Recently, an alternate isoform of CAR, CAREx8, has been identified at the apical surface of polarized airway epithelia and is implicated in viral infection from the apical surface. We hypothesized that the endogenous role of CAREx8 may be to facilitate host innate immunity. We show that IL-8, a proinflammatory cytokine and a neutrophil chemoattractant, stimulates the protein expression and apical localization of CAREx8 via activation of AKT/S6K and inhibition of GSK3β. Apical CAREx8 tethers infiltrating neutrophils at the apical surface of a polarized epithelium. Moreover, neutrophils present on the apical-epithelial surface enhance adenovirus entry into the epithelium. These findings suggest that adenovirus evolved to co-opt an innate immune response pathway that stimulates the expression of its primary receptor, apical CAREx8, to allow the initial infection the intact epithelium. In addition, CAREx8 is a new target for the development of novel therapeutics for both respiratory inflammatory disease and adenoviral infection.

  7. Hard tissue regeneration capacity of apical pulp derived cells (APDCs) from human tooth with immature apex.

    Science.gov (United States)

    Abe, Shigehiro; Yamaguchi, Satoshi; Watanabe, Akihiko; Hamada, Keiichi; Amagasa, Teruo

    2008-06-20

    Recent studies indicate that dental pulp is a new source of adult stem cells. The human tooth with an immature apex is a developing organ, and the apical pulp of this tooth may contain a variety of progenitor/stem cells, which participate in root formation. We investigated the hard tissue regeneration potential of apical pulp derived cells (APDCs) from human tooth with an immature apex. APDCs cultured with a mineralization-promoting medium showed alkaline phosphatase activity in porous hydroxyapatite (HA) scaffolds. The composites of APDCs and HA were implanted subcutaneously in immunocompromised rats and harvested at 12 weeks after implantation. In histological analysis, the APDCs/HA composites exhibited bone- and dentine-like mineralized tissues in the pore areas of HA. This study suggests that the human tooth with an immature apex is an effective source of cells for hard tissue regeneration.

  8. Filtración apical versus filtración coronal

    OpenAIRE

    2016-01-01

    La filtración del conducto radicular es la principal causa de los fracasos en endodoncia (19). Esta recontaminación puede producirse a través de dos vías principales de filtración que son los orificios coronal y apical. En la actualidad hay controversia entre diferentes autores sobre cuál es la vía de filtración más importante, si la apical (9, 167) o la coronal (4, 76). Existen diversas técnicas de obturación y materiales de obturación, entre las que puede elegir el clínico en función de cad...

  9. Neurons derive from the more apical daughter in asymmetric divisions in the zebrafish neural tube.

    Science.gov (United States)

    Alexandre, Paula; Reugels, Alexander M; Barker, David; Blanc, Eric; Clarke, Jonathan D W

    2010-06-01

    In the developing CNS, asymmetric cell division is critical for maintaining the balanced production of differentiating neurons while renewing the population of neural progenitors. In invertebrates, this process depends on asymmetric inheritance of fate determinants during progenitor divisions. A similar mechanism is widely believed to underlie asymmetrically fated divisions in vertebrates, but compelling evidence for this is missing. We used live imaging of individual progenitors in the intact zebrafish embryo CNS to test this hypothesis. We found that asymmetric inheritance of a subcellular domain is strongly correlated with asymmetric daughter fates and our results reveal an unexpected feature of this process. The daughter cell destined to become a neuron was derived from the more apical of the two daughters, whereas the more basal daughter inherited the basal process and replenished the apical progenitor pool.

  10. The effect of root preparation technique and instrumentation length on the development of apical root cracks.

    Science.gov (United States)

    Adorno, Carlos G; Yoshioka, Takatomo; Suda, Hideaki

    2009-03-01

    The purpose of this study was to compare the effects of root canal preparation techniques and instrumentation length on the development of apical root cracks. Forty extracted mandibular premolars with straight roots were randomly selected and mounted on resin blocks with simulated periodontal ligaments, and the apex was exposed. The teeth were divided into four groups of 10 teeth each for different canal preparation techniques and instrumentation lengths: group A: step-back preparation (SB) with stainless steel files (SF) using root canal length (RCL) to guide instrumentation length; group B: SB using RCL - 1 mm; group C: crown-down preparation (CD) with Profile using RCL; and group D: CD with PF using RCL - 1 mm. Digital images of the instrumentation sequence were compared for each tooth. Statistical analysis revealed a significant effect of instrumentation length (p 0.05) on the development of apical cracks.

  11. CRIP homologues maintain apical cytoskeleton to regulate tubule size in C. elegans.

    Science.gov (United States)

    Tong, Xiangyan; Buechner, Matthew

    2008-05-01

    Maintenance of the shape and diameter of biological tubules is a critical task in the development and physiology of all metazoan organisms. We have cloned the exc-9 gene of Caenorhabditis elegans, which regulates the diameter of the single-cell excretory canal tubules. exc-9 encodes a homologue of the highly expressed mammalian intestinal LIM-domain protein CRIP, whose function has not previously been determined. A second well-conserved CRIP homologue functions in multiple valves of C. elegans. EXC-9 shows genetic interactions with other EXC proteins, including the EXC-5 guanine exchange factor that regulates CDC-42 activity. EXC-9 and its nematode homologue act in polarized epithelial cells that must maintain great flexibility at their apical surface; our results suggest that CRIPs function to maintain cytoskeletal flexibility at the apical surface.

  12. Sealing ability of grar MTA AngelusTM, CPM TM and MBPc used as apical plugs

    Directory of Open Access Journals (Sweden)

    Fernando Accorsi Orosco

    2008-02-01

    Full Text Available This study evaluated the sealing ability of apical plugs fabricated with gray MTA AngelusTM sealer, CPM TM sealer and MBPc sealer. The root canals of 98 extracted single-rooted human teeth were instrumented with #5 to #1 Gates Glidden drills according to the crown-down technique until the #1 drill could pass through the apical foramen. The specimens were then prepared with K-files, starting with an ISO 50 until an ISO 90 could be visualized 1 mm beyond the apex. After root canal preparation, the external surface of each root was rendered impermeable and roots were assigned to 3 experimental groups (n = 30, which received a 5-mm thick apical plug of gray MTA AngelusTM, CPM TM and MBPc, and two control groups (n=4. The remaining portion of the canal in the experimental groups was filled by the lateral condensation technique. The teeth of each group, properly identified, were fixed on utility wax by their crowns and were placed in plastic flasks, leaving the apex free and facing upward. The flasks were filled with 0.2% Rhodamine B solution, pH 7.0, so as to completely cover the root apex of all teeth. The sealing ability was analyzed by measuring 0.2% Rhodamine B leakage after all groups had been maintained in this solution for 48 hours. Data were analyzed statistically by Kruskal-Wallis test and Dunn test with a=5%. The results showed that, among the tested materials used for fabrication of apical plugs, MBPc sealer had the least amount of leakage with statistically significant difference (p<0.05.

  13. Evaluation Value of Three Methods in the Diagnosis of Dentin Cracks Caused by Apical Resection

    Directory of Open Access Journals (Sweden)

    Abdollah Ghorbanzadeh

    2013-01-01

    Full Text Available Objective: To compare three various methods in the diagnosis of dentinal cracks formed in the apical third after root resection.Materials and Methods: One hundred extracted human maxillary central incisors were selected. The root canals were prepared with step-back technique. Then 3mm from the apical end of all roots was cut perpendicular to the long axis of the tooth. The apical end of each root was evaluated to make sure there were no cracks. Fifty specimens were randomly chosen and connected to an apparatus especially designed for application of force (50-60N by a universal testing machine for crack formation. The cracked (no=50 and non-cracked (no=50 specimens were examined by three methods of fiber optic transillumination, methylene blue staining and combination of the two. Sensitivity and specificity of the methods were evaluated. The most suitable method for detecting cracks was determined using Youden index. To compare agreement between studied methods with the gold standard, kappa statistics and odds ratio of McNemar were utilized.Results: The sensitivity of transillumination, staining and the combination method were 82.0, 50.0 and 90.0%, respectively. The staining technique had the lowest sensitivity and the highest specificity. Both transillumination and the combination method had Youden index of 0.56, but the combination method diagnosed truly cracked samples more than the other techniques.Conclusion: The efficacy of transillumination in identification of apical root-end cracks undetectable by unaided vision was similar to the combination method. However, the efficacy of 2% methylene blue without transillumination was significantly lower than the other two methodologies.

  14. Apical groove type and molecular phylogeny suggests reclassification of Cochlodinium geminatum as Polykrikos geminatum.

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    Dajun Qiu

    Full Text Available Traditionally Cocholodinium and Gymnodinium sensu lato clade are distinguished based on the cingulum turn number, which has been increasingly recognized to be inadequate for Gymnodiniales genus classification. This has been improved by the combination of the apical groove characteristics and molecular phylogeny, which has led to the erection of several new genera (Takayama, Akashiwo, Karenia, and Karlodinium. Taking the apical groove characteristics and molecular phylogeny combined approach, we reexamined the historically taxonomically uncertain species Cochlodinium geminatum that formed massive blooms in Pearl River Estuary, China, in recent years. Samples were collected from a bloom in 2011 for morphological, characteristic pigment, and molecular analyses. We found that the cingulum in this species wraps around the cell body about 1.2 turns on average but can appear under the light microscopy to be >1.5 turns after the cells have been preserved. The shape of its apical groove, however, was stably an open-ended anticlockwise loop of kidney bean shape, similar to that of Polykrikos. Furthermore, the molecular phylogenetic analysis using 18S rRNA-ITS-28S rRNA gene cistron we obtained in this study also consistently placed this species closest to Polykrikos within the Gymnodinium sensu stricto clade and set it far separated from the clade of Cochlodinium. These results suggest that this species should be transferred to Polykrikos as Polykrikos geminatum. Our results reiterate the need to use the combination of apical groove morphology and molecular phylogeny for the classification of species within the genus of Cochlodinium and other Gymnodiniales lineages.

  15. sTNF-R Levels: Apical Periodontitis Linked to Coronary Heart Disease

    Science.gov (United States)

    Singhal, Rajnish K.; Rai, Balwant

    2017-01-01

    BACKGROUND: Different studies have implicated the exposure to systemic conditions in the aetiology of cardiovascular diseases like chronic inflammation including chronic periodontitis. AIM: The present study has been conducted to examine whether biomarker sTNF-R was elevated in apical periodontitis as sTNF-R is a systemic marker of inflammation and has been identified as risk factors for cardiovascular diseases. MATERIAL AND METHODS: sTNF-R levels were measured in 52 patients with apical periodontitis (M:F::25:27), aged 20-45 years and in 20 control patients without periodontitis (M:F::10:10, aged 20-48 years). Measurement of sTNF-R1 and sTNF-R2 was carried out in duplicate with standardised, commercially available enzyme immunoassays (R&D Systems Europe, Abingdon, UK). RESULTS: The mean sTNF-R1 and sTNF-R2 levels in periodontitis were 820 (240) pg/ml (413 – 1620 pg/ml) and 1309 (403) pg/ml (540 – 2430 pg/ml), while in normal sTNF-R1 and sTNF – R2 levels were 740 (340) pg/ml (407-1240 pg/ml) and 1283 (414) pg (480 – 2340 pg/ml) respectively. Results indicated a positive high relationship between cardiovascular markers such as sTNF-R1 and sTNF – R2 and apical periodontitis. CONCLUSION: Elevated levels of sTNF-R1 and sTNF – R2 in apical periodontitis patients indicate an increased independent risk of coronary heart disease. PMID:28293320

  16. Morphologic analysis of apical resorption on human teeth with periapical lesions

    OpenAIRE

    2000-01-01

    Objective: The aim of this study was to compare the presence and extension of cementum and dentin resorption in apexes containing different periapical pathosis. Material and method: 31 teeth were selected for the presence of a proliferative tissue compatible with a periapical pathology. Sections were conducted in periapical lesions which were then dyed by the HE. The periapical pathosis were classified in fibrous connective tissue, granuloma and cysts. The apical root surfaces were submitted ...

  17. Differentiation of apical and basal dendrites in pyramidal cells and granule cells in dissociated hippocampal cultures.

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    You Kure Wu

    Full Text Available Hippocampal pyramidal cells and dentate granule cells develop morphologically distinct dendritic arbors, yet also share some common features. Both cell types form a long apical dendrite which extends from the apex of the cell soma, while short basal dendrites are developed only in pyramidal cells. Using quantitative morphometric analyses of mouse hippocampal cultures, we evaluated the differences in dendritic arborization patterns between pyramidal and granule cells. Furthermore, we observed and described the final apical dendrite determination during dendritic polarization by time-lapse imaging. Pyramidal and granule cells in culture exhibited similar dendritic patterns with a single principal dendrite and several minor dendrites so that the cell types were not readily distinguished by appearance. While basal dendrites in granule cells are normally degraded by adulthood in vivo, cultured granule cells retained their minor dendrites. Asymmetric growth of a single principal dendrite harboring the Golgi was observed in both cell types soon after the onset of dendritic growth. Time-lapse imaging revealed that up until the second week in culture, final principal dendrite designation was not stabilized, but was frequently replaced by other minor dendrites. Before dendritic polarity was stabilized, the Golgi moved dynamically within the soma and was repeatedly repositioned at newly emerging principal dendrites. Our results suggest that polarized growth of the apical dendrite is regulated by cell intrinsic programs, while regression of basal dendrites requires cue(s from the extracellular environment in the dentate gyrus. The apical dendrite designation is determined from among multiple growing dendrites of young developing neurons.

  18. Comparing the apical microleakage of lateral condensation and chloroform dip techniques with a new obturation method

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    Masoud Saatchi

    2011-01-01

    Full Text Available Background: The final objective of root canal therapy is to create a hermetic seal along the length of the root canal system. For this purpose, many methods and materials have been introduced. The purpose of this study was to compare the apical microleakage in a new obturation technique (true-tug-back with two other obturation techniques (lateral condensation and chloroform dip technique. Methods: In this in vitro study 102 single canal teeth were selected. The crowns were removed, and the canals were prepared using step-back technique. The master apical file was K-file #40. The teeth were divided into 3 experimental groups of 32 teeth. First group were obturated with lateral condensation technique and second group with chloroform dip technique and the third group with true-tug-back technique. Six teeth were used as control group. The teeth were placed in incubator at 100% humidity and 37°c for three days. The roots of the teeth were coated with two layers of nail varnish except for the apical 2 millimeter. Teeth were placed in Methylene blue 2% for one week. The teeth were sectioned vertically and the depth of maximum dye penetration for each tooth was recorded by stereomicroscope. Data were analyzed using ANOVA and Dunkan test. Results: The mean liner dye penetration differences between lateral condensation group (6.88 ± 4.06 mm and chloroform dip technique group (7.16 ± 3.37 mm were not statistically significant (P = 0.719. The differences between true-tug-back group (3.15 ± 0.52 mm and two other groups were statistically significant (P < 0.001. Conclusion: The results of this study showed that the true-tug-back technique can improve apical seal. Further studies are needed for this purpose.

  19. Sealing ability of grar MTA AngelusTM, CPM TM and MBPc used as apical plugs.

    Science.gov (United States)

    Orosco, Fernando Accorsi; Bramante, Clovis Monteiro; Garcia, Roberto Brandão; Bernadineli, Norberti; Moraes, Ivaldo Gomes de

    2008-01-01

    This study evaluated the sealing ability of apical plugs fabricated with gray MTA Angelus sealer, CPM TM sealer and MBPc sealer. The root canals of 98 extracted single-rooted human teeth were instrumented with #5 to #1 Gates Glidden drills according to the crown-down technique until the #1 drill could pass through the apical foramen. The specimens were then prepared with K-files, starting with an ISO 50 until an ISO 90 could be visualized 1 mm beyond the apex. After root canal preparation, the external surface of each root was rendered impermeable and roots were assigned to 3 experimental groups (n = 30), which received a 5-mm thick apical plug of gray MTA Angelus, CPM and MBPc, and two control groups (n=4). The remaining portion of the canal in the experimental groups was filled by the lateral condensation technique. The teeth of each group, properly identified, were fixed on utility wax by their crowns and were placed in plastic flasks, leaving the apex free and facing upward. The flasks were filled with 0.2% Rhodamine B solution, pH 7.0, so as to completely cover the root apex of all teeth. The sealing ability was analyzed by measuring 0.2% Rhodamine B leakage after all groups had been maintained in this solution for 48 hours. Data were analyzed statistically by Kruskal-Wallis test and Dunn test with a=5%. The results showed that, among the tested materials used for fabrication of apical plugs, MBPc sealer had the least amount of leakage with statistically significant difference (p<0.05).

  20. The Rho Target PRK2 Regulates Apical Junction Formation in Human Bronchial Epithelial Cells ▿

    OpenAIRE

    Wallace, Sean W.; Magalhaes, Ana; Hall, Alan

    2010-01-01

    Rho GTPases regulate multiple signaling pathways to control a number of cellular processes during epithelial morphogenesis. To investigate the downstream pathways through which Rho regulates epithelial apical junction formation, we screened a small interfering RNA (siRNA) library targeting 28 known Rho target proteins in 16HBE human bronchial epithelial cells. This led to the identification of the serine-threonine kinase PRK2 (protein kinase C-related kinase 2, also called PKN2). Depletion of...

  1. Uptake and Distribution of Aluminum in Root Apices of Two Rice Varieties under Aluminum Stress

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    MIFTAHUDIN

    2007-09-01

    Full Text Available Aluminum (Al toxicity is the major limiting factor of plant growth and production in acid soils. The target of Al toxicity is the root tip, which affects mainly on root growth inhibition. The aim of this research was to study the uptake and distribution of Al in root apices of two rice varieties IR64 (Al-sensitive and Krowal (Al-tolerant, which were grown on nutrient solution containing 0, 15, 30, 45, and 60 ppm of Al. The root growth was significantly inhibited in both rice varieties at as low as 15 ppm Al concentration. The adventive roots of both varieties showed stunted growth in respons to Al stress. There was no difference in root growth inhibition between both rice varieties as well as among Al concentrations. Al uptake on root apices was qualitatively and quantitatively analyzed. Histochemical staining of roots using hematoxylin showed dark purple color on 1 mm region of Al-treated root apices. Rice var. IR 64 tended to take up more Al in root tip than Krowal did. However, there was no statistically significant difference (p = 0.176 in root Al content of both varieties in response to different concentration and period of Al treatments. Al distribution in root apices was found in the epidermal and subepidermal region in both rice varieties. Based on those results, rice var. Krowal that was previously grouped as Al-tolerant variety has similar root growth and physiological response to Al stress as compared to Al-sensitive variety IR64.

  2. A new approach to supply chain management based on pooling ITIL and APICS Principles and Practices

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    Abdelaali Himi

    2011-07-01

    Full Text Available APICS (Advanced Productivity, Innovation and Competitive Success - The Association for Operations Management is known as the repository providing a set of best practices in Supply Chain Management. The ITIL (Information Technology Infrastructure Library also provides best practices for IT service management. Noting the existence of a similarity between these two standards, this paper identifies the ITIL concepts used in the supply chain context and describe their contributions.

  3. An investigation on the effects of resection angle on apical sea!

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    Razmi H

    2003-08-01

    Full Text Available Statement of Problem: The goal of a successful endodontic surgery is to establish an adequate seal in apical region. Therefore during surgery, root-end resection is essential for an appropriate situation and proper access."nPurpose: The aim of this study was to determine the most appropriate root-end resection angle to establish adequate apical seal in periapical surgery,"nMaterials and Methods: Forty-five intact extracted human maxillary central incisors were randomly divided into three 15-tooth groups. The root canals were instrumented and then obturated using lateral condensation technique. AM roots were resected at 3mm from apical portion. Angles of root resection for each group were 0, 30 and 45 degrees. Then all teeth surfaces, except the cut ones, were covered with nail polish and immersed in methylen blue for 7 days. After 7 days, nail polish was removed from the surfaces and samples were split in buccolingual direction. Then, dye penetration (mm was measured using a stereozoom microscope (Loupe [X4 magnification] and eye lens. In order to analyze the data, unilateral variance analysis was used."nResults: The values of dye penetration were: 7.23±3.34 (0°, 8.46±3.01(30° and 9.74±4.11 (45°. There"nwas no significant difference between three groups (P>0.05. Conclusion: It is suggested that the angle of root-end resection put a limited effect on apical seal if retrograde cavity depth is increased.

  4. Coordinated regulation of apical hook development by gibberellins and ethylene in etiolated Arabidopsis seedlings.

    Science.gov (United States)

    An, Fengying; Zhang, Xing; Zhu, Ziqiang; Ji, Yusi; He, Wenrong; Jiang, Zhiqiang; Li, Mingzhe; Guo, Hongwei

    2012-05-01

    Dark-grown Arabidopsis seedlings develop an apical hook when germinating in soil, which protects the cotyledons and apical meristematic tissues when protruding through the soil. Several hormones are reported to distinctly modulate this process. Previous studies have shown that ethylene and gibberellins (GAs) coordinately regulate the hook development, although the underlying molecular mechanism is largely unknown. Here we showed that GA(3) enhanced while paclobutrazol repressed ethylene- and EIN3-overexpression (EIN3ox)-induced hook curvature, and della mutant exhibited exaggerated hook curvature, which required an intact ethylene signaling pathway. Genetic study revealed that GA-enhanced hook development was dependent on HOOKLESS 1 (HLS1), a central regulator mediating the input of the multiple signaling pathways during apical hook development. We further found that GA(3) induced (and DELLA proteins repressed) HLS1 expression in an ETHYLENE INSENSITIVE 3/EIN3-LIKE 1 (EIN3/EIL1)-dependent manner, whereby EIN3/EIL1 activated HLS1 transcription by directly binding to its promoter. Additionally, DELLA proteins were found to interact with the DNA-binding domains of EIN3/EIL1 and repress EIN3/EIL1-regulated HLS1 expression. Treatment with naphthylphthalamic acid, a polar auxin transport inhibitor, repressed the constitutively exaggerated hook curvature of EIN3ox line and della mutant, supporting that auxin functions downstream of the ethylene and GA pathways in hook development. Taken together, our results identify EIN3/EIL1 as a new class of DELLA-associated transcription factors and demonstrate that GA promotes apical hook formation in cooperation with ethylene partly by inducing the expression of HLS1 via derepression of EIN3/EIL1 functions.

  5. Coordinated regulation of apical hook development by gibberellins and ethylene in etiolated Arabidopsis seedlings

    Institute of Scientific and Technical Information of China (English)

    Fengying An; Xing Zhang; Ziqiang Zhu; Yusi Ji; Wenrong He; Zhiqiang Jiang; Mingzhe Li; Hongwei Guo

    2012-01-01

    Dark-grown Arabidopsis seedlings develop an apical hook when germinating in soil,which protects the cotyledons and apical meristematic tissues when protruding through the soil.Several hormones are reported to distinctly modulate this process.Previous studies have shown that ethylene and gibberellins (GAs) coordinately regulate the hook development,although the underlying molecular mechanism is largely unknown.Here we showed that GA3 enhanced while paclobutrazol repressed ethylene- and EIN3-overexpression (EIN3ox)-induced hook curvature,and della mutant exhibited exaggerated hook curvature,which required an intact ethylene signaling pathway.Genetic study revealed that GA-enhanced hook development was dependent on HOOKLESS 1 (HLS1),a central regulator mediating the input of the multiple signaling pathways during apical hook development.We further found that GA3 induced (and DELLA proteins repressed) HLS1 expression in an ETHYLENE INSENSITIVE 3/EIN3-LIKE 1 (EIN3/EIL1)-dependent manner,whereby EIN3/EIL1 activated HLS1 transcription by directly binding to its promoter.Additionally,DELLA proteins were found to interact with the DNA-binding domains of EIN3/EIL1 and repress EIN3/EIL1-regulated HLS1 expression.Treatment with naphthylphthalamic acid,a polar auxin transport inhibitor,repressed the constitutively exaggerated hook curvature of EIN3ox line and della mutant,supporting that auxin functions downstream of the ethylene and GA pathways in hook development.Taken together,our results identify EIN3/EIL1 as a new class of DELLA-associated transcription factors and demonstrate that GA promotes apical hook formation in cooperation with ethylene partly by inducing the expression of HLS1 via derepression of EIN3/EIL1 functions.

  6. One-step apexification using platelet rich fibrin matrix and mineral trioxide aggregate apical barrier

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    Anisha Kumar

    2014-01-01

    In one-step apexification using MTA, the technical problem encountered is controlling the overfill or underfill of MTA. The use of a matrix material helps to overcome this shortcoming. Platelet rich fibrin (PRF is an immune platelet concentrate, which can be used as a matrix, it also promotes wound healing and repair. This case report presents a case of one step apexification using MTA as an apical barrier and autologous PRF as an internal matrix.

  7. Effects of Long-term Right Ventricular Apical Pacing on Left Ventricular Remodeling and Cardiac Function

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective: To investigate the impacts of long-term right ventricular apical pacing on the ventricular remodeling and cardiac functions of patients with high-grade and third-degree atrioventricular blockage with normal heart structures and cardiac functions. In addition, we provide many evidences for choosing an optimal electrode implantation site.Methods: Study participants included patients who were admitted for pacemaker replacements and revisited for examinations of implanted pacemakers at outpatient. Pa...

  8. Expression analysis of Matrix Metalloproteinase-9 in epithelialized and non-epithelialized apical periodontitis lesions

    Science.gov (United States)

    Carneiro, Everdan; Menezes, Renato; Garlet, Gustavo Pompermaier; Garcia, Roberto Brandão; Bramante, Clóvis Monteiro; Figueira, Rita; Sogayar, Mari; Granjeiro, José Mauro

    2009-01-01

    OBJECTIVE To determine the expression of matrix metalloproteinase-9 (MMP-9) in apical periodontitis lesions. STUDY DESIGN Nineteen epithelialized and eighteen non-epithelialized apical periodontitis lesions were collected after periapical surgery. After histological processing, serial sectioning, H&E staining and microscopic analysis, 10 epithelialized and 10 non-epithelialized lesions were selected for immunohistochemical analysis for MMP-9 and CD 68. At least 1/3 of each specimen was frozen at −70°C for further mRNA isolation and reverse transcription into cDNA for Real-Time-PCR procedures. The relative expression of a target gene was determined in comparison with reference genes (GAPDH, HPRT, β-actin and BCRP). RESULTS Polymorphonuclear neutrophils, macrophages and lymphocytes were stained for MMP-9 in both types of lesions, and when present, epithelial cells were also stained. The number and the ratio of MMP-9+/total cells were greater in non-epithelialized than epithelialized lesions (p=0.0001) and showed a positive correlation to CD68+/total cells (p=0.045). No significant differences were observed for MMP-9 mRNA expression between ephithelized and non-ephithelized lesions. However, when compared to healthy periapical ligaments, both types of lesions presented increased MMP-9 expression (p<0.0001). CONCLUSION The present data suggest the participation of several inflammatory cells, mainlly CD68+ cells, in the MMP-9 expression in apical periodontitis lesions. MMP-9 could be actively enroled in the ECM degradation in apical periodontitis lesions. PMID:18926740

  9. Comparison of apical debris extrusion of two rotary systems and one reciprocating system

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    Paramasivam Vivekanandhan

    2016-01-01

    Full Text Available Background: Postoperative inflammation and endodontic failure occur due to apical extrusion of debris. Aim: To evaluate the amount of apically extruded debris after preparation of straight root canals in extracted human teeth using three rotary systems. Materials and Methods: Sixty single-rooted human teeth with single root canal and apical foramen were selected and randomly divided into three experimental groups (n = 20 according to the rotary system used: Group 1 - ProTaper, Group 2 - Revo-S, Group 3 - WaveOne. Apical enlargement was done up to size 40/0.06 for Groups 1 and 2 and 40/0.08 for Group 3. For debris collection, each tooth was held in a preweighed Eppendorf tube fixed inside a glass vial through rubber plug. After instrumentation, each tooth was separated from the Eppendorf tube and the debris adhering to the root surface was collected by washing the root with 1 mL of bi-distilled water and incubated at 70°C for 5 days. The dry weight of extruded debris was weighed in an electronic balance. Statistical Analysis: The mean weights of extruded debris were statistically analyzed using GraphPad prism version 6 and the intergroup comparison was done using unpaired t-test. Results: There was a statistically significant difference in the mean debris score among all the three groups - ProTaper (0.00065 g, Revo-S (0.00045 g and WaveOne (0.00089 g. Conclusion: Revo-S system was associated with significantly less debris extrusion compared with ProTaper or WaveOne.

  10. Hepatic and Renal Failure after Anterior Myocardial Infarction Induced Apical Ventricular Septal Defect

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    Dirk Lossnitzer

    2010-01-01

    Full Text Available We report the case of a 68-year-old man suffering from incremental hepatic and renal failure one month after anterior myocardial infarction. Cardiac MRI showed a pronounced apical post-AMI aneurysm, a moderate to severe mitral and tricuspid regurgitation as well as a hemodynamically highly significant 12 mm apical ventricular septal defect with a left-to-right ventricular shunt of almost 63% as the underlying cause. Heart X-ray revealed a severe LAD in-stent restenosis. CAPD catheter drainage of hydroperitoneum due to congestive liver and renal failure was provided in combination with intensified CAPD hemodialysis. Heart surgery was performed where the apical aneurysm was excised, the mitral valve was reconstructed, the IVSD was closed and the subtotally in-stent occluded LAD was bypassed. Post-surgery, the ascites were significantly reduced, and CAPD hemodialysis therapy could be terminated since the renal function gradually improved (MDRD = 25 mL/min. To our knowledge, for the first time we report successful CAPD catheter drainage of hydroperitoneum in combination with CAPD hemodialysis.

  11. Hypertrophic cardiomyopathy with midventricular obstruction and apical aneurysm formation in a single family: case report

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    Paraskevaidis Stylianos

    2009-06-01

    Full Text Available Abstract Background Hypertrophic cardiomyopathy (HCM is an extremely heterogeneous disease. An under recognized and very often missed subgroup within this broad spectrum concerns patients with left ventricular (LV apical aneurysms in the absence of coronary artery disease. Case presentation We describe a case of HCM with midventricular obstruction and apical aneurysm formation in 3 patients coming from a single family. This HCM pattern was detected by 2D-echocardiography and confirmed by cardiac magnetic resonance imaging. A cardioverter defibrillator was implanted in one of the patients because of non-sustained ventricular tachycardia detected in 24-h Holter monitoring and an abrupt drop in systolic blood pressure during maximal exercise test. The defibrillator activated 8 months after implantation by suppression of a ventricular tachycardia providing anti-tachycardia pacing. The patient died due to refractory heart failure 2 years after initial evaluation. The rest of the patients are stable after a 2.5-y follow-up period. Conclusion The detection of apical aneurysm by echocardiography in HCM patients may be complicated. Ventricular tachycardia arising from the scarred aneurysm wall may often occur predisposing to sudden death.

  12. Integrins Regulate Apical Constriction via Microtubule Stabilization in the Drosophila Eye Disc Epithelium

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    Vilaiwan M. Fernandes

    2014-12-01

    Full Text Available During morphogenesis, extracellular signals trigger actomyosin contractility in subpopulations of cells to coordinate changes in cell shape. To illuminate the link between signaling-mediated tissue patterning and cytoskeletal remodeling, we study the progression of the morphogenetic furrow (MF, the wave of apical constriction that traverses the Drosophila eye imaginal disc preceding photoreceptor neurogenesis. Apical constriction depends on actomyosin contractility downstream of the Hedgehog (Hh and bone morphogenetic protein (BMP pathways. We identify a role for integrin adhesion receptors in MF progression. We show that Hh and BMP regulate integrin expression, the loss of which disrupts apical constriction and slows furrow progression; conversely, elevated integrins accelerate furrow progression. We present evidence that integrins regulate MF progression by promoting microtubule stabilization, since reducing microtubule stability rescues integrin-mediated furrow acceleration. Thus, integrins act as a genetic link between tissue-level signaling events and morphological change at the cellular level, leading to morphogenesis and neurogenesis in the eye.

  13. Época apropriada para a poda apical do algodoeiro para o controle de pragas

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    Robério Carlos dos Santos Neves

    2010-12-01

    Full Text Available O objetivo deste trabalho foi determinar a época apropriada para a realização da poda apical em algodoeiro. O trabalho foi realizado durante as safras de 2008 e 2009 (maio a novembro em delineamento de blocos ao acaso, em dois ambientes, com as variedades: BRS 201, de fibra branca, e BRS Rubi, BRS Safira e BRS Verde, de fibra colorida, em Paudalho, PE; e BRS 201 e BRS Rubi, em Surubim, PE. A poda apical consistiu na retirada dos ápices das plantas com estruturas vegetativas e reprodutivas, em duas idades fenológicas: com 50% das maçãs maduras (poda I e no surgimento dos primeiros capulhos (poda II. A poda I resultou em maior retirada de botões florais do que a poda II. Em ambas as podas, houve a retirada de cinco nós dos ponteiros. A produção e a qualidade de fibra não diferiram entre plantas podadas ou não. Um número significativo de estruturas atacadas foi eliminado pela poda. A poda apical é recomendada para reduzir o número de estruturas não produtivas, ao final da safra, que são utilizadas como hospedeiras de pragas

  14. Phosphatidylserine-positive particles in the apical domain of sensory hair cells

    Institute of Scientific and Technical Information of China (English)

    SHI Xiao-rui; Alfred Nuttall

    2006-01-01

    Apical membrane recycling has been proposed to be important for normal hair cell function. The current study reports an in vitro work that demonstrates the presence of phosphatidylserine (PS) and PS-positive vesicles labeled by Annexin V in the apical portion of hair cells. The following characteristics of the PS-positive vesicles were noticed using scanning confocal fluorescence microscopy: (1) variable sizes around 200 nm; (2)variable distribution patterns (either uniformly along individual stereocilia in the hair bundle or irregular) in the stereocilia from cell to cell; (3) variable sizes and numbers at locations along the border of the cuticular plate (CP),with a large number of them located at the vestigal kinocilial location; (4) motility with some of the vesicles during the observation period; (5) increase in PS labeling and the number of PS-positive vesicles after loud sound stimulation; and (6) decreased PS labeling and PS-positive vesicle numbers following treatment with LY-294002, a PI3 -kinase inhibitor. These results suggest that the presence of PS-positive vesicles at the apical area of hair cells may be indicative of vesicle shedding or transportation of a protein or rafts.

  15. Supraventricular tachycardia in a patient with Lown-Ganong-Levine syndrome associated with apical hypertrophic cardiomyopathy.

    Science.gov (United States)

    Hayano, M; Imamura, Y; Tsuruta, M; Inoue, J; Nakashima, H; Fukuyama, K; Eguchi, Y; Tsuji, S; Matsuo, S; Yano, K

    1988-03-01

    Electrophysiologic study of a 55-year-old patient with Lown-Ganong-Levine syndrome associated with apical hypertrophic cardiomyopathy is reported. The patient had a history of recurrent attacks of tachyarrhythmia and his electrocardiogram showed a short P-R interval (0.10 sec) with narrow QRS complex and left ventricular hypertrophy with giant negative T waves. His cineangiogram showed severe apical hypertrophy. An electrophysiologic study was performed. The results of programmed atrial pacing show the existence of the dual A-V nodal pathways. The A-H interval at rapid atrial pacing increased maximally by 103 msec. Atrial stimulation could depolarize parts of the atrium without altering the supraventricular tachycardia. These findings suggested that preferential rapidly conducting A-V nodal and intranodal reentry are the responsible mechanisms in this reciprocating tachycardia. We conclude that the short P-R interval was due to intranodal reentry through the dual A-V nodal pathways. To our knowledge, a case of Lown-Ganong-Levine syndrome with apical hypertrophic cardiomyopathy has not been previously described in the literature.

  16. Master apical file size - smaller or larger: a systematic review of microbial reduction.

    Science.gov (United States)

    Aminoshariae, A; Kulild, J

    2015-11-01

    The purpose of this systematic review was to determine, in patients undergoing root canal treatment, whether apical enlargement of canals affected microbial reduction. A PICO (population, intervention, comparison and outcome) strategy was developed to identify previously published studies dealing with apical size of canal and microbial reduction. The MEDLINE, Embase, Cochrane and PubMed databases were searched. Additionally, the bibliographies of all relevant articles and textbooks were manually searched. Based on inclusion and exclusion criteria, two reviewers independently selected the relevant articles. Due to the variety of methodologies and different techniques used to measure outcome for master apical file enlargement, it was not possible to standardize the research data and to apply a meta-analysis. Seven articles were identified that met the inclusion criteria. Five of the seven articles generally concluded that canal enlargement reduced bioburden in the root canal system. Two articles reported no difference in canals enlarged to size 25 or 40. The results of the systematic review confirmed that more evidence-based research in this area is needed. With the limited information currently available, the best current available clinical evidence suggests that contemporary chemomechanical debridement techniques with canal enlargement techniques do not eliminate bacteria during root canal treatment at any size.

  17. The Rho target PRK2 regulates apical junction formation in human bronchial epithelial cells.

    Science.gov (United States)

    Wallace, Sean W; Magalhaes, Ana; Hall, Alan

    2011-01-01

    Rho GTPases regulate multiple signaling pathways to control a number of cellular processes during epithelial morphogenesis. To investigate the downstream pathways through which Rho regulates epithelial apical junction formation, we screened a small interfering RNA (siRNA) library targeting 28 known Rho target proteins in 16HBE human bronchial epithelial cells. This led to the identification of the serine-threonine kinase PRK2 (protein kinase C-related kinase 2, also called PKN2). Depletion of PRK2 does not block the initial formation of primordial junctions at nascent cell-cell contacts but does prevent their maturation into apical junctions. PRK2 is recruited to primordial junctions, and this localization depends on its C2-like domain. Rho binding is essential for PRK2 function and also facilitates PRK2 recruitment to junctions. Kinase-dead PRK2 acts as a dominant-negative mutant and prevents apical junction formation. We conclude that PRK2 is recruited to nascent cell-cell contacts through its C2-like and Rho-binding domains and promotes junctional maturation through a kinase-dependent pathway.

  18. Class III phosphoinositide 3-kinase/VPS34 and dynamin are critical for apical endocytic recycling.

    Science.gov (United States)

    Carpentier, Sarah; N'Kuli, Francisca; Grieco, Giuseppina; Van Der Smissen, Patrick; Janssens, Virginie; Emonard, Hervé; Bilanges, Benoît; Vanhaesebroeck, Bart; Gaide Chevronnay, Héloïse P; Pierreux, Christophe E; Tyteca, Donatienne; Courtoy, Pierre J

    2013-08-01

    Recycling is a limiting step for receptor-mediated endocytosis. We first report three in vitro or in vivo evidences that class III PI3K/VPS34 is the key PI3K isoform regulating apical recycling. A substractive approach, comparing in Opossum Kidney (OK) cells a pan-class I/II/III PI3K inhibitor (LY294002) with a class I/II PI3K inhibitor (ZSTK474), suggested that class III PI3K/VPS34 inhibition induced selective apical endosome swelling and sequestration of the endocytic receptor, megalin/LRP-2, causing surface down-regulation. GFP-(FYVE)x2 overexpression to sequester PI(3)P caused undistinguishable apical endosome swelling. In mouse kidney proximal tubular cells, conditional Vps34 inactivation also led to vacuolation and intracellular megalin redistribution. We next report that removal of LY294002 from LY294002-treated OK cells induced a spectacular burst of recycling tubules and restoration of megalin surface pool. Acute triggering of recycling tubules revealed recruitment of dynamin-GFP and dependence of dynamin-GTPase, guidance directionality by microtubules, and suggested that a microfilamentous net constrained endosomal swelling. We conclude that (i) besides its role in endosome fusion, PI3K-III is essential for endosome fission/recycling; and (ii) besides its role in endocytic entry, dynamin also supports tubulation of recycling endosomes. The unleashing of recycling upon acute reversal of PI3K inhibition may help study its dynamics and associated machineries.

  19. Thalamic input to distal apical dendrites in neocortical layer 1 is massive and highly convergent.

    Science.gov (United States)

    Rubio-Garrido, Pablo; Pérez-de-Manzo, Flor; Porrero, César; Galazo, Maria J; Clascá, Francisco

    2009-10-01

    Input to apical dendritic tufts is now deemed crucial for associative learning, attention, and similar "feedback" interactions in the cerebral cortex. Excitatory input to apical tufts in neocortical layer 1 has been traditionally assumed to be predominantly cortical, as thalamic pathways directed to this layer were regarded relatively scant and diffuse. However, the sensitive tracing methods used in the present study show that, throughout the rat neocortex, large numbers (mean approximately 4500/mm(2)) of thalamocortical neurons converge in layer 1 and that this convergence gives rise to a very high local density of thalamic terminals. Moreover, we show that the layer 1-projecting neurons are present in large numbers in most, but not all, motor, association, limbic, and sensory nuclei of the rodent thalamus. Some layer 1-projecting axons branch to innervate large swaths of the cerebral hemisphere, whereas others arborize within only a single cortical area. Present data imply that realistic modeling of cortical circuitry should factor in a dense axonal canopy carrying highly convergent thalamocortical input to pyramidal cell apical tufts. In addition, they are consistent with the notion that layer 1-projecting axons may be a robust anatomical substrate for extensive "feedback" interactions between cortical areas via the thalamus.

  20. Diagnosis and planning in apical surgery: use of cone-beam tomography

    Directory of Open Access Journals (Sweden)

    Regina Karla de Pontes Lima

    2010-10-01

    Full Text Available Introduction and objective: The ability to tridimensionally evaluate pathological and anatomical areas, in apical surgery planning, presents a number of advantages. Cone beam computed tomography (CBCT was developed for dental applications. This paper aims to present a literature review on CBCT, highlighting its advantages over both conventional computed tomography (CT and radiography. Moreover, its clinical applications in apical surgery are discussed. Literature review and conclusion: Unlikely CT, CBCT captures a volume of data in a single 360° rotation, providing benefits such as higher accuracy, better resolution, reduced scanning time and reduced radiation dose. In the maxillofacial region, CBCT has been mainly used in the assessment of dento-alveolar pathology and oral traumatology. CBCT provides a better diagnosis and quantitative information on periodontal bone levels than conventional radiography. It has also been used for patients requiring surgical facial reconstruction, orthognathic surgery, dental implants, and more complex tooth extractions. Besides that, it seems to be a significant tool in modern endodontic practice, presenting useful applications in apical surgery.

  1. Sample preparation for laser-microdissection of soybean shoot apical meristem

    Directory of Open Access Journals (Sweden)

    Chui E. Wong

    2012-10-01

    Full Text Available The shoot apical meristem houses stem cells responsible for the continuous formation of aerial plant organs including leaves and stems throughout the life of plants. Laser-microdissection in combination with high-throughput technology such as next generation sequencing permits an in-depth analysis of molecular events associated with specific cell type of interest. Sample preparation is the most critical step in ensuring good quality RNA to be extracted from samples following laser-microdissection. Here, we optimized the sample preparation for a major legume crop, soybean. We used Farmer’s solution as a fixative and paraffin as the embedding medium for soybean shoot apical meristem tissue without the use of any specialized equipment. Shorter time for tissue fixation (two days was found to be critical for the preservation of RNA in soybean shoot apical meristem. We further demonstrated the utility of this method for different tissues derived from soybean and rice. The method outlined here shall facilitate studies on crop plants involving laser-microdissection.

  2. Differential growth at the apical hook: all roads lead to auxin.

    Directory of Open Access Journals (Sweden)

    Mohamad eAbbas

    2013-11-01

    Full Text Available The apical hook is a developmentally regulated structure that appears in dicotyledonous seedlings when seeds germinate buried in the soil. It protects the shoot apical meristem and cotyledons from damage while the seedling is pushing upwards seeking for light, and it is formed by differential cell expansion between both sides of the upper part of the hypocotyl. Its apparent simplicity and the fact that it is dispensable when seedlings are grown in vitro have converted the apical hook in one of the favorite experimental models to study the regulation of differential growth. The involvement of hormones –especially auxin– in this process was manifest already in the early studies. Remarkably, a gradient of this hormone across the hook curvature is instrumental to complete its development, similar to what has been proposed for other processes involving the bending of an organ, such as tropic responses. In agreement with this, other hormones –mainly gibberellins and ethylene–, and the light, regulate in a timely and interconnected manner the auxin gradient to promote hook development and its opening, respectively. Here, we review the latest findings in the field, paying special attention to the molecular mechanisms for the cross-regulation between the different hormone signaling pathways that underlie this developmental process.

  3. The ability of two apex locators to locate the apical foramen: an in vitro study.

    Science.gov (United States)

    D'Assunção, Fábio Luiz Cunha; de Albuquerque, Diana Santana; de Queiroz Ferreira, Linalda Correia

    2006-06-01

    The objective of this study was to compare the accuracy of the Root-ZX and Novapex electronic apex locators (EALs) in locating the apical foramen. Forty extracted human teeth were used. The coronal portion of each canal was flared using Gates Glidden drill. Canals were irrigated with 2.5% sodium hypochlorite. The actual length (AL) and electronic length (EL) measurements were made on each specimen separately with both devices with an aid of a K-type file. The results obtained with each EAL were compared with the corresponding control length. The statistical analysis of the results showed EAL reliability in detecting the apical foramen to 89.7% for the Root-ZX and 82.1% for the Novapex, taking the tolerance of +/-0.5 mm into account. A paired sample t test showed that there was no statistically significant difference between the accuracy of the devices (p = 0.4305). The results of this study indicate that the Root-ZX and Novapex are useful and accurate devices for the apical foramen location.

  4. Prevalence of Enterococcus faecalis in saliva and filled root canals of teeth associated with apical periodontitis.

    Science.gov (United States)

    Wang, Qian-Qian; Zhang, Cheng-Fei; Chu, Chun-Hung; Zhu, Xiao-Fei

    2012-03-01

    To investigate the prevalence of Enterococcus faecalis in saliva and filled root canals of patients requiring endodontic retreatment for apical periodontitis. Patients with apical periodontitis who were referred for endodontic retreatment were examined. The type and quality of the restoration, symptoms, quality of obturation were recorded. During retreatment, an oral rinse sample and root canal sample were cultured using brain-heart infusion agar and bile esculinazide agar to select for E. faecalis. The 16S rRNA technique was used to identify E. faecalis. A total of 32 women and 22 men (mean age: 38 years; s.d.: 11 years) and 58 teeth were studied. The prevalence of E. faecalis was 19% in the saliva and 38% in the root canals. The odds that root canals harbored E. faecalis were increased if the saliva habored this bacterium (odds ratio=9.7; 95% confidence interval=1.8-51.6; Pfaecalis is more common in root canals of teeth with apical periodontitis than in saliva. The prevalence of E. faecalis in root canals is associated with the presence of E. faecalis in saliva.

  5. Effect of nickel titanium file design on the root surface strain and apical microcracks.

    Science.gov (United States)

    Jamleh, Ahmed; Adorno, Carlos G; Ebihara, Arata; Suda, Hideaki

    2016-04-01

    The aim of this study was to determine the effect of nickel titanium file design on the root surface strain generated and apical microcracks caused during canal shaping. Thirty-three mandibular incisors were distributed into LightSpeed X, FlexMaster and a control group. A strain gauge was fixed apically on the proximal root surface to determine the maximum strain during canal shaping. Except for the control group, all root canals were enlarged to size 50. Images were taken after removing the apical 1 and 2 mm of the root end. Mean maximum strain values and presence of microcracks were statistically compared using the t-test and chi-square test, respectively. During canal shaping, the strain increased cumulatively with mean maximum strains of 808.2 ± 228.8 and 525.1 ± 168.9 microstrain in LightSpeed X and FlexMaster, respectively (P = 0.004). Both systems caused comparable microcracks. Although LightSpeed X produced higher maximum strain, no difference in microcrack development was found between both systems.

  6. Heterogeneity of myocardial fluoro-18 2-deoxyglucose uptake in patients with apical hypertrophic cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, Nobuyuki; Kagaya, Yutaka; Ishide, Nobumasa [Tohoku Univ., Sendai (Japan). School of Medicine] [and others

    1997-03-01

    We have shown that myocardial glucose metabolism is heterogeneous in patients with hypertrophic cardiomyopathy. It is not known, however, whether glucose metabolism is impaired in patients with apical hypertrophic cardiomyopathy, which is fairly common in Japan. We studied 7 patients with apical hypertrophic cardiomyopathy and 5 normal subjects using fluoro-18 2-deoxyglucose (FDG) and positron emission tomography (PET). We calculated regional FDG fractional uptake and the inter-regional coefficient of variation (CV) of FDG fractional uptake in the interventricular septal, anteroapical, and posterolateral regions. The regional FDG fractional uptake was similar in the 2 groups and among the 3 different segments within each group. However, the inter-regional CV of FDG fractional uptake was increased in the anteroapical wall segment of the patient group compared with the control group and also with the other 2 regions in the patient group. The results did not differ when we studied another 5 patients and 6 normal control subjects with a PET scanner with higher spatial resolution. These data suggest that myocardial glucose metabolism may be impaired in the anteroapical wall segment of patients with apical hypertrophic cardiomyopathy. (author)

  7. Takotsubo, discinesia apical transitoria: Presentacion de 4 casos y revisión de la literatura Takotsubo, reversible apical ballooning of the left ventricle: Report of 4 cases

    Directory of Open Access Journals (Sweden)

    Bárbara C. Finn

    2005-10-01

    Full Text Available En 1990 se describió un síndrome caracterizado por discinesia apical transitoria, cambios en el electrocardiograma (ECG, mínima elevación de enzimas cardíacas y arterias coronarias normales. Se presenta con mayor frecuencia en mujeres añosas y es precedido por un evento de estrés, ya sea físico o psíquico. La fisiopatología aún no está aclarada y se proponen diversas teorías. La de mayor peso es la que postula una afección secundaria a la descarga de catecolaminas desencadenada por el estrés, sobre un corazón incapaz de mantener una respuesta inotrópica adecuada. Se presentan cuatro casos de pacientes atendidos en nuestro hospital que se manifestaron con síntomas sugerentes de infarto agudo de miocardio asociados a insuficiencia cardiaca, en el contexto de un episodio estresante. Los síntomas preponderantes fueron dolor precordial opresivo y disnea. En el ECG se evidenciaron tanto supradesnivel del segmento ST, como inversión de la onda T. Todos los pacientes presentaron la imagen ecocardiográfica típica de discinesia apical, y todos tuvieron en la cinecoronariografía coronarias normales. Cabe destacar que tanto el ECG, como el ecocardiograma volvieron a la normalidad a partir de las dos semanas.A syndrome of apical ballooning, with ECG mimicking acute myocardial infarctation, mild or no enzymatic changes, and normal coronary angiogram was described in 1990. It presents mainly in middle aged and elderly women and it is preceded by stress triggering circumstances. Several mechanisms have been proposed although the precise cause remains unclear. The most accepted theory proposes the interaction of catecholamines and an inadequate inotropic response. We report four cases that presented with chest pain and sudden onset of heart failure, all patients had physical or emotional stress as a triggering factor. On ECG, ST segment elevation and inverted T waves were observed in the acute phase. All patients had typical echocardiogram

  8. The effect of bevel angle on apical microleakage following the use of amalgam and MTA

    Directory of Open Access Journals (Sweden)

    Sharifian MR

    2006-07-01

    Full Text Available Background and Aim: Achieving appropriate seal in canal obturation is the main goal of endodontic therapy. However, in some cases, it can not be obtained by non-surgical procedures alone. Retrograde surgery is one of the most common procedures in endodontics. Apical seal improvement can be obtained by root end filling and decreasing the root end resection angle (bevel angle. The aim of this study was to investigate the role of bevel angle on apical microleakage following the use of amalgam and MTA as root end filling materials. Materials and Methods: In this experimental study, 128 extracted human teeth were instrumented and obturated by lateral condensation technique. The teeth were divided into two groups and the apical root resection was performed by high speed fissure bur (one group perpendicular to the long axis of the teeth and the other 45 to the long axis. The 3 mm root end cavity was prepared by ultrasonic device. Each group was divided into two subgroups: One filled with amalgam and the other with MTA. Teeth were incubated for 72 h, covered by two layers of nail polish (except for apical 3mm and submerged in methylene blue for 48 h. Teeth were washed under tap water and mesiodistally dissected by low speed disc. Dye penetration was evaluated by stereomicroscope. Data were analysed by two way ANOVA and Tukey tests with p<0.05 as the limit of significance. Results: The results showed that retrofill material type had a significant effect on microleakage and MTA was superior to amalgam in this respect. Bevel angle failed to show any significant effect on apical microleakage. Conclusion: Based on the results of this study, it seems that the use of MTA instead of amalgam in clinical practice can improve the success rate of endodontic surgery whereas the bevel angle can be determined based on the status of each individual case; However, increasing the bevel angle seems to increase microleakage due to exposure of more dentinal tubules.

  9. [Deformations occurring in the apical third of curved root canals during biomechanical preparation using manual impulsion-traction techniques].

    Science.gov (United States)

    Roig Cayón, M; Basilio Monné, J; Canalda Sahli, C

    1990-01-01

    Apical deformations, specially zips and elbows, during instrumentation of the root canals, are studied. The authors study why do they appear, their effect on endodontic therapy, and the way of avoiding them.

  10. Membrane-assisted mineral trioxide aggregate apical plug for management of traumatized immature anterior teeth: Clinical case reports

    Directory of Open Access Journals (Sweden)

    Raji Viola Solomon

    2014-01-01

    Full Text Available Apexification using calcium hydroxide has many disadvantages, such as, it needs more time for the treatment, chance for fracture of the tooth, and incomplete calcification of the bridge. There are many alternative treatments introduced, which have gained popularity, such as, forming an apical plug using mineral trioxide aggregate (MTA, for excellent results. In cases of wide open apices, it is difficult to limit the restoration to the working length, as such situations lead to the apical extrusion of the material into the periapical region, which prevents further healing. Such conditions can be best treated with the use of a resorbable collagen membrane, which limits the restoration till the working length and prevents the extrusion of the material beyond the apex. The present case reports highlight the non-surgical management of immature teeth by using a membrane as a barrier, with an MTA apical plug, followed by crown rehabilitation.

  11. Effect of Instrumentation Length and Instrumentation Systems: Hand Versus Rotary Files on Apical Crack Formation – An In vitro Study

    Science.gov (United States)

    Mahesh, MC; Bhandary, Shreetha

    2017-01-01

    Introduction Stresses generated during root canal instrumentation have been reported to cause apical cracks. The smaller, less pronounced defects like cracks can later propagate into vertical root fracture, when the tooth is subjected to repeated stresses from endodontic or restorative procedures. Aim This study evaluated occurrence of apical cracks with stainless steel hand files, rotary NiTi RaCe and K3 files at two different instrumentation lengths. Materials and Methods In the present in vitro study, 60 mandibular premolars were mounted in resin blocks with simulated periodontal ligament. Apical 3 mm of the root surfaces were exposed and stained using India ink. Preoperative images of root apices were obtained at 100x using stereomicroscope. The teeth were divided into six groups of 10 each. First two groups were instrumented with stainless steel files, next two groups with rotary NiTi RaCe files and the last two groups with rotary NiTi K3 files. The instrumentation was carried out till the apical foramen (Working Length-WL) and 1 mm short of the apical foramen (WL-1) with each file system. After root canal instrumentation, postoperative images of root apices were obtained. Preoperative and postoperative images were compared and the occurrence of cracks was recorded. Descriptive statistical analysis and Chi-square tests were used to analyze the results. Results Apical root cracks were seen in 30%, 35% and 20% of teeth instrumented with K-files, RaCe files and K3 files respectively. There was no statistical significance among three instrumentation systems in the formation of apical cracks (p=0.563). Apical cracks were seen in 40% and 20% of teeth instrumented with K-files; 60% and 10% of teeth with RaCe files and 40% and 0% of teeth with K3 files at WL and WL-1 respectively. For groups instrumented with hand files there was no statistical significance in number of cracks at WL and WL-1 (p=0.628). But for teeth instrumented with RaCe files and K3 files

  12. Participation of IAA in transduction of gravistimulus in apical cells of moss protonema

    Science.gov (United States)

    Oksyniuk, U. A.; Khorkavtsiv, O. Y.; Lesniak, Y. I.

    Growth movements of vascular plant axis organs -- photo-, gravi- and other tropisms -- are tightly connected with IAA transport (Hertel, 1983; Medvedev, 1996; Kiss, 2000). Moss protonema synthesizes IAA (indole-3-acetic acid) and transports it basipetally favouring growth and differentiation of caulonema (Bopp, 1979; Rose, Bopp, 1983; Rose et al., 1983). We aimed at studying the role of IAA in moss protonema gravitropism using exogenous IAA, 1-NAA (1-naphthaleneacetic acid), 2,4D (2,4-dichlorophenoxyacetic acid) and inhibitors of polar IAA transport -- phytotropins NPA (N-1-naphthylphthalamic acid) and TIBA (2,3,5-triiodobenzoic acid). Six-day gravitropic protonema of Ceratodon purpureus and Pohlia nutans were taken for experiments. Auxin and phytotropins solutions were laid on protonema mats the latters being kept in solutions for 30 min. Then the surplus of solutions were poured off and Petri dishes were placed vertically for 6 h. 20 μ M of IAA and of other synthetic auxins did not significantly influence the angle of protonema gravity bending, 40 μ M of the agents, howewer, reduced the per cent of apical cells bendings and their angles. The most expressed influence on the angles of bending had the inhibitors of polar IAA transport -- NPA. 0,1 -- 3,0 μ M of this phytotropin did not change the form of apical cell, did not disturb the general distribution of amyloplasts and did not significantly lower the per cent and the value of gravity bending angle, though 10 μ M of the phytotropin - inhibited gravity bending. The mixture of 1-NAA and NPA having been added into the medium the influence of NPA was lowered and gravitropic growth renewed in course of time. 10 μ M of other phytopropin TIBA also inhibited gravitropism of Ceratodon purpureus and Pohlia nutans protonema. The analysis of basipetal transport of IAA in moss rhizoids and protonema may indicate the availability of special IAA transport in these structures (Bopp, Cerier, 1988). On the basis of the

  13. A possible association between early apical resorption of primary teeth and ectodermal characteristics of the permanent dentition

    DEFF Research Database (Denmark)

    Bille, M L B; Kvetny, M J; Kjaer, I

    2008-01-01

    The hypothesis of this study is that children with unexpected early apical resorption of the primary teeth are also predisposed to resorption in the permanent dentition. Accordingly, the aim was to perform a longitudinal study focussing on the permanent teeth in children with unexpected early api...... dentition: In all 12 children, dental deviations in the permanent dentition were observed. Additionally, idiopathic external apical resorption of the permanent teeth was seen in three children, two of whom had received orthodontic treatment....

  14. A posteriori registration and subtraction of periapical radiographs for the evaluation of external apical root resorption after orthodontic treatment

    OpenAIRE

    2016-01-01

    Purpose This study employed a posteriori registration and subtraction of radiographic images to quantify the apical root resorption in maxillary permanent central incisors after orthodontic treatment, and assessed whether the external apical root resorption (EARR) was related to a range of parameters involved in the treatment. Materials and Methods A sample of 79 patients (mean age, 13.5±2.2 years) with no history of trauma or endodontic treatment of the maxillary permanent central incisors w...

  15. Cardiomiopatia hipertrófica apical associada a doença arterial coronária Apical hypertrophic cardiomyopathy associated with coronary artery disease

    Directory of Open Access Journals (Sweden)

    Francisco Manes Albanesi Fº

    1998-08-01

    Full Text Available Homem de 59 anos, portador de cardiomiopatia hipertrófica apical há 12 anos, apresentou agudização de quadro anginoso. Foi detectada doença arterial coronária com lesão trivascular, e indicada cirurgia de revascularização, com anastomose de artéria mamária e a colocação de duas pontes de veia safena, tendo evoluído com melhora do quadro anginoso e redução da dimensão do átrio esquerdo.A fifty-nine year old man, known to have hypertrophic cardiomyopathy, presented worsening of angina. Multivessel coronary artery disease was diagnosed, and he underwent myocardial revascularization (mammary and two safenous grafts were implanted with good evolution and reduction of left atrium dimension.

  16. Fractal dimension of apical dendritic arborization differs in the superficial and the deep pyramidal neurons of the rat cerebral neocortex.

    Science.gov (United States)

    Puškaš, Nela; Zaletel, Ivan; Stefanović, Bratislav D; Ristanović, Dušan

    2015-03-04

    Pyramidal neurons of the mammalian cerebral cortex have specific structure and pattern of organization that involves the presence of apical dendrite. Morphology of the apical dendrite is well-known, but quantification of its complexity still remains open. Fractal analysis has proved to be a valuable method for analyzing the complexity of dendrite morphology. The aim of this study was to establish the fractal dimension of apical dendrite arborization of pyramidal neurons in distinct neocortical laminae by using the modified box-counting method. A total of thirty, Golgi impregnated neurons from the rat brain were analyzed: 15 superficial (cell bodies located within lamina II-III), and 15 deep pyramidal neurons (cell bodies situated within lamina V-VI). Analysis of topological parameters of apical dendrite arborization showed no statistical differences except in total dendritic length (p=0.02), indicating considerable homogeneity between the two groups of neurons. On the other hand, average fractal dimension of apical dendrite was 1.33±0.06 for the superficial and 1.24±0.04 for the deep cortical neurons, showing statistically significant difference between these two groups (pfractal dimension values, apical dendrites of the superficial pyramidal neurons tend to show higher structural complexity compared to the deep ones.

  17. Root reconstructed with mineral trioxide aggregate and guided tissue regeneration in apical surgery: a 5-year follow-up.

    Science.gov (United States)

    Bernabé, Pedro Felício Estrada; Azuma, Mariane Maffei; Ferreira, Luciana Louzada; Dezan-Júnior, Eloi; Gomes-Filho, João Eduardo; Cintra, Luciano Tavares Angelo

    2013-01-01

    Apical surgery should be considered as the last treatment option and employed when conventional endodontic treatment does not provide the expected result. In teeth undergoing apical surgery, the type of retrograde filling material is one of the factors interfering with the repair of periapical tissues. The material in intimate contact with the periapical tissues plays a fundamental role in the repair process. Several materials have been studied and indicated for use in apical surgery procedures, but the mineral trioxide aggregate (MTA) is still the most frequently used one. Guided tissue regeneration (GTR) techniques have been proposed as an adjunct to apical surgery to enhance bone healing. Here is reported a clinical case in which apical surgery was performed in conjunction with MTA-based root reconstruction of the maxillary right second incisor. After the apical surgery, a root-end cavity was prepared at the vestibular face of the involved tooth and filled with MTA. A bovine bone graft and a cortical collagen membrane were placed on the bone defect. After 5 years, clinical and radiographic assessments showed that the treatment was successful. It may be concluded that MTA presents favorable characteristics in adverse conditions and can be used in conjunction with GTR in cases involving root reconstruction.

  18. Mineral trioxide aggregate apical plug method for the treatment of nonvital immature permanent maxillary incisors: Three case reports

    Directory of Open Access Journals (Sweden)

    Betül Günes

    2012-01-01

    Full Text Available Treatment of nonvital immature permanent teeth with calcium-hydroxide is associated with some difficulties such as weakened tooth fracture, root canal reinfection and long treatment time. Mineral trioxide aggregate (MTA apical plug method is an alternative treatment option for open apices, and has gained popularity in the recent times. In this case report, we have attempted to present successful treatment of three maxillary incisors with open apices and periapical lesions with MTA. After preparing the access cavity, the working length was determined. The root canals were irrigated with 2.5% Sodium hypochlorite (NaOCl and disinfected with calcium-hydroxide for two weeks. MTA was then placed in the apical 3 millimeters of the root canal. The remaining part of the root canal was filled with gutta-percha and the coronal restoration was finished with composite resin. After six months the radiographic examination showed a decrease of periapical lesions. At a 1-year and 18-months follow up, radiological and clinical successful healing of the incisor teeth was seen. MTA seems as an effective material for the apical plug method for the treatment of nonvital immature permanent teeth with open apices.

  19. Effect of Flumorph on F-Actin Dynamics in the Potato Late Blight Pathogen Phytophthora infestans.

    Science.gov (United States)

    Hua, Chenlei; Kots, Kiki; Ketelaar, Tijs; Govers, Francine; Meijer, Harold J G

    2015-04-01

    Oomycetes are fungal-like pathogens that cause notorious diseases. Protecting crops against oomycetes requires regular spraying with chemicals, many with an unknown mode of action. In the 1990s, flumorph was identified as a novel crop protection agent. It was shown to inhibit the growth of oomycete pathogens including Phytophthora spp., presumably by targeting actin. We recently generated transgenic Phytophthora infestans strains that express Lifeact-enhanced green fluorescent protein (eGFP), which enabled us to monitor the actin cytoskeleton during hyphal growth. For analyzing effects of oomicides on the actin cytoskeleton in vivo, the P. infestans Lifeact-eGFP strain is an excellent tool. Here, we confirm that flumorph is an oomicide with growth inhibitory activity. Microscopic analyses showed that low flumorph concentrations provoked hyphal tip swellings accompanied by accumulation of actin plaques in the apex, a feature reminiscent of tips of nongrowing hyphae. At higher concentrations, swelling was more pronounced and accompanied by an increase in hyphal bursting events. However, in hyphae that remained intact, actin filaments were indistinguishable from those in nontreated, nongrowing hyphae. In contrast, in hyphae treated with the actin depolymerizing drug latrunculin B, no hyphal bursting was observed but the actin filaments were completely disrupted. This difference demonstrates that actin is not the primary target of flumorph.

  20. Effect of flumorph on F-actin dynamics in the potato late blight pathogen Phytophthora infestans

    NARCIS (Netherlands)

    Hua, C.; Kots, K.; Ketelaar, T.; Govers, F.; Meijer, H.J.G.

    2015-01-01

    Oomycetes are fungal-like pathogens that cause notorious diseases. Protecting crops against oomycetes requires regular spraying with chemicals, many of which with unknown mode of action. In the 1990’s, flumorph was identified as a novel crop protection agent. It was shown to inhibit the growth of oo

  1. Contractile Units in Disordered Actomyosin Bundles Arise from F-Actin Buckling

    Science.gov (United States)

    Lenz, Martin; Thoresen, Todd; Gardel, Margaret L.; Dinner, Aaron R.

    2012-06-01

    Bundles of filaments and motors are central to contractility in cells. The classic example is striated muscle, where actomyosin contractility is mediated by highly organized sarcomeres which act as fundamental contractile units. However, many contractile bundles in vivo and in vitro lack sarcomeric organization. Here we propose a model for how contractility can arise in bundles without sarcomeric organization and validate its predictions with experiments on a reconstituted system. In the model, internal stresses in frustrated arrangements of motors with diverse velocities cause filaments to buckle, leading to overall shortening. We describe the onset of buckling in the presence of stochastic motor head detachment and predict that buckling-induced contraction occurs in an intermediate range of motor densities. We then calculate the size of the “contractile units” associated with this process. Consistent with these results, our reconstituted actomyosin bundles show contraction at relatively high motor density, and we observe buckling at the predicted length scale.

  2. Total Synthesis of (-)-Doliculide, Structure-Activity Relationship Studies and Its Binding to F-Actin

    NARCIS (Netherlands)

    Matcha, Kiran; Madduri, Ashoka V. R.; Roy, Sayantani; Ziegler, Slava; Waldmann, Herbert; Hirsch, Anna K. H.; Minnaard, Adriaan J.

    2012-01-01

    Actin, an abundant protein in most eukaryotic cells, is one of the targets in cancer research. Recently, a great deal of attention has been paid to the synthesis and function of actin-targeting compounds and their use as effective molecular probes in chemical biology. In this study, we have develope

  3. Drosophila Imp iCLIP identifies an RNA assemblage coordinating F-actin formation

    DEFF Research Database (Denmark)

    Hansen, Heidi Theil; Rasmussen, Simon Horskjær; Adolph, Sidsel Kramshøj;

    2015-01-01

    BACKGROUND: Post-transcriptional RNA regulons ensure co-ordinated expression of monocistronic mRNAs encoding functionally related proteins. In this study, we employ a combination of RIP-seq and short- and long-wave individual-nucleotide resolution crosslinking and immunoprecipitation (iCLIP...

  4. Class 3 semaphorins induce F-actin reorganization in human dendritic cells: Role in cell migration.

    Science.gov (United States)

    Curreli, Sabrina; Wong, Bin Sheng; Latinovic, Olga; Konstantopoulos, Konstantinos; Stamatos, Nicholas M

    2016-12-01

    Class 3 semaphorins (Semas) are soluble proteins that are well recognized for their role in guiding axonal migration during neuronal development. In the immune system, Sema3A has been shown to influence murine dendritic cell (DC) migration by signaling through a neuropilin (NRP)-1/plexin-A1 coreceptor axis. Potential roles for class 3 Semas in human DCs have yet to be described. We tested the hypothesis that Sema3A, -3C, and -3F, each with a unique NRP-1 and/or NRP-2 binding specificity, influence human DC migration. In this report, we find that although NRP-1 and NRP-2 are expressed in human immature DCs (imDCs), NRP-2 expression increases as cells mature further, whereas expression of NRP-1 declines dramatically. Elevated levels of RNA encoding plexin-A1 and -A3 are present in both imDCs and mature DC (mDCs), supporting the relevance of Sema/NRP/plexin signaling pathways in these cells. Sema3A, -3C, and -3F bind to human DCs, with Sema3F binding predominantly through NRP-2. The binding of these Semas leads to reorganization of actin filaments at the plasma membrane and increased transwell migration in the absence or presence of chemokine CCL19. Microfluidic chamber assays failed to demonstrate consistent changes in speed of Sema3C-treated DCs, suggesting increased cell deformability as a possible explanation for enhanced transwell migration. Although monocytes express RNA encoding Sema3A, -3C, and -3F, only RNA encoding Sema3C increases robustly during DC differentiation. These data suggest that Sema3A, -3C, and -3F, likely with coreceptors NRP-1, NRP-2, and plexin-A1 and/or -A3, promote migration and possibly other activities of human DCs during innate and adaptive immune responses.

  5. Cofilin phosphorylation is elevated after F-actin disassembly induced by Rac1 depletion

    DEFF Research Database (Denmark)

    Liu, Linna; Li, Jing; Zhang, Liwang

    2015-01-01

    that actin filaments disassembled. In the epidermis of mice in which Rac1 was knocked out only in keratinocytes, cofilin phosphorylation was aberrantly elevated, corresponding to repression of the phosphatase slingshot1 (SSH1). These effects were independent of the signaling pathways for p21-activated kinase....../LIM kinase (Pak/LIMK), protein kinase C, or protein kinase D or generation of reactive oxygen species. Similarly, when actin polymerization was specifically inhibited or Rac1 was knocked down, cofilin phosphorylation was enhanced and SSH1 was repressed. Repression of SSH1 partially blocked actin...

  6. Reversibility and Viscoelastic Properties of Micropillar Supported and Oriented Magnesium Bundled F-Actin.

    Directory of Open Access Journals (Sweden)

    Timo Maier

    Full Text Available Filamentous actin is one of the most important cytoskeletal elements. Not only is it responsible for the elastic properties of many cell types, but it also plays a vital role in cellular adhesion and motility. Understanding the bundling kinetics of actin filaments is important in the formation of various cytoskeletal structures, such as filopodia and stress fibers. Utilizing a unique pillar-structured microfluidic device, we investigated the time dependence of bundling kinetics of pillar supported free-standing actin filaments. Microparticles attached to the filaments allowed the measurement of thermal motion, and we found that bundling takes place at lower concentrations than previously found in 3-dimensional actin gels, i.e. actin filaments formed bundles in the presence of 5-12 mM of magnesium chloride in a time-dependent manner. The filaments also displayed long term stability for up to hours after removing the magnesium ions from the buffer, which suggests that there is an extensive hysteresis between cation induced crosslinking and decrosslinking.

  7. Contractile units in disordered actomyosin bundles arise from F-actin buckling

    CERN Document Server

    Lenz, Martin; Gardel, Margaret L; Dinner, Aaron R

    2012-01-01

    Bundles of filaments and motors are central to contractility in cells. The classic example is striated muscle, where actomyosin contractility is mediated by highly organized sarcomeres which act as fundamental contractile units. However, many contractile bundles in vivo and in vitro lack sarcomeric organization. Here we propose a model for how contractility can arise in actomyosin bundles without sarcomeric organization and validate its predictions with experiments on a reconstituted system. In the model, internal stresses in frustrated arrangements of motors with diverse velocities cause filaments to buckle, leading to overall shortening. We describe the onset of buckling in the presence of stochastic actin-myosin detachment and predict that buckling-induced contraction occurs in an intermediate range of motor densities. We then calculate the size of the "contractile units" associated with this process. Consistent with these results, our reconstituted actomyosin bundles contract at relatively high motor dens...

  8. Natural selection and population genetic structure of domain-I of Plasmodium falciparum apical membrane antigen-1 in India.

    Science.gov (United States)

    Basu, Madhumita; Maji, Ardhendu Kumar; Mitra, Mitashree; Sengupta, Sanghamitra

    2013-08-01

    Development of a vaccine against Plasmodium falciparum infection is an urgent priority particularly because of widespread resistance to most traditionally used drugs. Multiple evidences point to apical membrane antigen-1(AMA-1) as a prime vaccine candidate directed against P. falciparum asexual blood-stages. To gain understanding of the genetic and demographic forces shaping the parasite sequence diversity in Kolkata, a part of Pfama-1 gene covering domain-I was sequenced from 100 blood samples of malaria patients. Statistical and phylogenetic analyses of the sequences were performed using DnaSP and MEGA. Very high haplotype diversity was detected both at nucleotide (0.998±0.002) and amino-acid (0.996±0.001) levels. An abundance of low frequency polymorphisms (Tajima's D=-1.190, Fu & Li's D(∗) and F(∗)=-3.068 and -2.722), unimodal mismatch distribution and a star-like median-joining network of ama-1 haplotypes indicated a recent population expansion among Kolkata parasites. The high minimum number of recombination events (Rm=26) and a significantly high dN/dS of 3.705 (PIgNAR. Alterations in the desolvation and global energies of PfAMA-1-PfRON2 interaction complexes at the hotspot contact residues were observed together with redistribution of surface electrostatic potentials at the variant alleles with respect to referent Pf3D7 sequence. Finally, a comparison of P. falciparum subpopulations in five Indian regional isolates retrieved from GenBank revealed a significant level of genetic differentiation (FST=0.084-0.129) with respect to Kolkata sequences. Collectively, our results indicated a very high allelic and haplotype diversity, a high recombination rate and a signature of natural selection favoring accumulation of non-synonymous substitutions that facilitated PfAMA-1-PfRON2 interaction and hence parasite growth in Kolkata clinical isolates.

  9. Delay enhancement patterns in apical hypertrophic cardiomyopathy by phase-sensitive inversion recovery sequence

    Institute of Scientific and Technical Information of China (English)

    Zi-Yi Guo; Jing Chen; Qi-Zhou Liang; Hai-Yan Liao; Shui-Xi Fu; Qian-Yu Tang; Cai-Xiang Chen; Xiang-Jun Han; Feng Gao

    2012-01-01

    Objective:Late gadolinium enhancement (LGE) patterns of cardiovascular magnetic resonance (CMR) relying on PSIR (phase-sensitive inversion recovery sequence) techniques had been used to determine the characteristics of LGE in apical hypertrophic cardiomyopathy (ApHCM). Methods:Forty patients pure ApHCM [age, (60.2±10.4) years, 31 men] were enrolled. LGE images were acquired using PSIR, and analyzed using a 17-segment model. Summing the LGE areas in all short axis slices yielded the total volume of late enhancement, which was subsequently presented as a proportion of total LV myocardium (%LGE). Results:Mean maximal apical wall thickness was (17.9±2.3) mm, and mean left ventricular (LV) ejection fraction was (67.7±8.0)%. LGE was detected in 130 segments of 30 patients (75.0%), occupying (4.9±5.5)%of LV myocardium. LGE was mainly detected at the junction between left and right ventricles in 12 (30%) and at the apex in 28 (70%), although LGE-positive areas were widely distributed, and not limited to the apex. Focal LGE at the non-hypertrophic LV segments was found in some ApHCM patients, even without LGE of hypertrophied apical segments. Conclusions: LGE was frequently observed not only in the thickened apex of the heart but also in other LV segments, irrespective of the presence or absence of hypertrophy. The simple presence of LGE on CMR was not representative of adverse prognosis in this population.

  10. An auxin responsive CLE gene regulates shoot apical meristem development in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Hongyan eGuo

    2015-05-01

    Full Text Available Plant hormone auxin regulates most, if not all aspects of plant growth and development, including lateral root formation, organ pattering, apical dominance and tropisms. Peptide hormones are peptides with hormone activities. Some of the functions of peptide hormones in regulating plant growth and development are similar to that of auxin, however, the relationship between auxin and peptide hormones remains largely unknown. Here we report the identification of OsCLE48, a rice (Oryza sativa CLE (CLAVATA3/ENDOSPERM SURROUNDING REGION gene, as an auxin response gene, and the functional characterization of OsCLE48 in Arabidopsis and rice. OsCLE48 encodes a CLE peptide hormone that is similar to Arabidopsis CLEs. RT-PCR analysis showed that OsCLE48 was induced by exogenously application of IAA (indole-3-acetic acid, a naturally occurred auxin. Expression of integrated OsCLE48p:GUS reporter gene in transgenic Arabidopsis plants was also induced by exogenously IAA treatment. These results indicate that OsCLE48 is an auxin responsive gene. Histochemical staining showed that GUS activity was detected in all the tissue and organs of the OsCLE48p:GUS transgenic Arabidopsis plants. Expression of OsCLE48 under the control of the 35S promoter in Arabidopsis inhibited shoot apical meristem development. Expression of OsCLE48 under the control of the CLV3 native regulatory elements almost completely complemented clv3-2 mutant phenotypes, suggesting that OsCLE48 is functionally similar to CLV3. On the other hand, expression of OsCLE48 under the control of the 35S promoter in Arabidopsis has little, if any effects on root apical meristem development, and transgenic rice plants overexpressing OsCLE48 are morphologically indistinguishable from wild type plants, suggesting that the functions of some CLE peptides may not be fully conserved in Arabidopsis and rice.

  11. Analysis of dental root apical morphology: a new method for dietary reconstructions in primates.

    Science.gov (United States)

    Hamon, NoÉmie; Emonet, Edouard-Georges; Chaimanee, Yaowalak; Guy, Franck; Tafforeau, Paul; Jaeger, Jean-Jacques

    2012-06-01

    The reconstruction of paleo-diets is an important task in the study of fossil primates. Previously, paleo-diet reconstructions were performed using different methods based on extant primate models. In particular, dental microwear or isotopic analyses provided accurate reconstructions for some fossil primates. However, there is sometimes difficult or impossible to apply these methods to fossil material. Therefore, the development of new, independent methods of diet reconstructions is crucial to improve our knowledge of primates paleobiology and paleoecology. This study aims to investigate the correlation between tooth root apical morphology and diet in primates, and its potential for paleo-diet reconstructions. Dental roots are composed of two portions: the eruptive portion with a smooth and regular surface, and the apical penetrative portion which displays an irregular and corrugated surface. Here, the angle formed by these two portions (aPE), and the ratio of penetrative portion over total root length (PPI), are calculated for each mandibular tooth root. A strong correlation between these two variables and the proportion of some food types (fruits, leaves, seeds, animal matter, and vertebrates) in diet is found, allowing the use of tooth root apical morphology as a tool for dietary reconstructions in primates. The method was then applied to the fossil hominoid Khoratpithecus piriyai, from the Late Miocene of Thailand. The paleo-diet deduced from aPE and PPI is dominated by fruits (>50%), associated with animal matter (1-25%). Leaves, vertebrates and most probably seeds were excluded from the diet of Khoratpithecus, which is consistent with previous studies.

  12. Effect of Simvastatin on induced apical periodontitis in rats: a tomographic and biochemical analysis

    Directory of Open Access Journals (Sweden)

    Jussara Machado PEREIRA

    Full Text Available Abstract Introduction Simvastatin is one of several statins that are used to treat hypercholesterolemia, and in dentistry, few studies have attempted to associate the administration of this compound with bone repair. Objective To evaluate the effect of simvastatin on the progression of induced apical periodontitis in rats. Material and method To this end, 36 male Wistar rats were divided into 3 groups (N=12: Induced Apical Periodontitis Associated with Simvastatin Group (APSG N=12, Induced Periodontitis Apical Induced Group (APG N=12 and Negative Control Group (CG. On the first day, APG and APSG were anesthetized, and the coronal opening of the mandibular first molar was performed. For thirty days, the APSG received 6 mg of simvastatin daily via gavage. On the thirty-first day, all groups underwent blood collection and euthanasia. The jaws were removed and fixed in formalin. CT scans were performed to measure the periapical regions. In addition, the body mass and lipid profile were analyzed. The data were subjected to statistical analysis (ANOVA and Tukey’s test. Result The APG (3.42±0.65 showed the highest perimeters for the space periapical ligament, followed by APSG (1.54±0.78 and CG (0.64±0.24 (p<0.05. The lipid profile revealed the effect of simvastatin on the amount of glucose, triglycerides, HDL, and VLDL (p<0.05. Body mass APG showed the most weight gain (264.75±44.11, followed by CG (252.00±44.36 and APSG (245.41±42.56. The three groups showed significant differences in decreasing order (p<0.05. Conclusion The use of simvastatin decreased the progression of the increasing periapical ligament space in rats.

  13. Apices of maxillary premolars observed by swept source optical coherence tomography

    Science.gov (United States)

    Ebihara, Arata; Iino, Yoshiko; Yoshioka, Toshihiko; Hanada, Takahiro; Sunakawa, Mitsuhiro; Sumi, Yasunori; Suda, Hideaki

    2015-02-01

    Apicoectomy is performed for the management of apical periodontitis when orthograde root canal treatment is not possible or is ineffective. Prior to the surgery, cone beam computed tomography (CBCT) examination is often performed to evaluate the lesion and the adjacent tissues. During the surgical procedure, the root apex is resected and the resected surface is usually observed under dental operating microscope (DOM). However, it is difficult to evaluate the details and the subsurface structure of the root using CBCT and DOM. A new diagnostic system, swept source optical coherence tomography (SS-OCT), has been developed to observe the subsurface anatomical structure. The aim of this study was to observe resected apical root canals of human maxillary premolars using SS-OCT and compare the findings with those observed using CBCT and DOM. Six extracted human maxillary premolars were used. After microfocus computed tomography (Micro CT; for gold standard) and CBCT scanning of the root, 1 mm of the apex was cut perpendicular to the long axis of the tooth. Each resected surface was treated with EDTA, irrigated with saline solution, and stained with methylene blue dye. The resected surface was observed with DOM and SS-OCT. This sequence was repeated three times. The number of root canals was counted and statistically evaluated. There was no significant difference in the accuracy of detecting root canals among CBCT, DOM and SS-OCT (p > 0.05, Wilcoxon test). Because SS-OCT can be used in real time during surgery, it would be a useful tool for observing resected apical root canals.

  14. Factors Influencing Selection of Vaginal, Open Abdominal, or Robotic Surgery to Treat Apical Vaginal Vault Prolapse

    Science.gov (United States)

    Anand, Mallika; Weaver, Amy L.; Fruth, Kristin M.; Gebhart, John B.

    2016-01-01

    Objectives To determine factors influencing selection of Mayo-McCall culdoplasty (MMC), open abdominal sacrocolpopexy (ASC), or robotic sacrocolpopexy (RSC) for posthysterectomy vaginal vault prolapse. Methods We retrospectively searched for the records of patients undergoing posthysterectomy apical vaginal prolapse surgery between January 1, 2000, and June 30, 2012, at our institution. Baseline characteristics and explicit selection factors were abstracted from the electronic medical records. Factors were compared between groups using χ2 tests for categorical variables, ANOVA for continuous variables, and Kruskal-Wallis tests for ordinal variables. Results Among the 512 patients identified who met inclusion criteria, the MMC group (n=174) had more patients who were older, American Society of Anesthesiologists class 3+ or greater, had anterior vaginal prolapse grade 3+, desired to avoid abdominal surgery, and did not desire a functional vagina. Patients in the ASC (n=237) and RSC (n=101) groups had more failed prolapse surgeries, suspected abdominopelvic pathologic processes, and chronic pain. Advanced prolapse was more frequently cited as an explicit selection factor for ASC than for either MMC or RSC. Conclusions The most common factors that influenced the type of apical vaginal vault prolapse surgery overlapped with characteristics that differed at baseline. In general, MMC was chosen for advanced anterior vaginal prolapse and baseline characteristics that increased surgical risks, ASC for advanced apical prolapse, and ASC or RSC for recurrent prolapse, suspected abdominal pathology, and patients with chronic pain or lifestyles including heavy lifting. Thus, efforts should be made to attempt to control for selection bias when comparing these procedures. PMID:26945273

  15. Evaluation of apical extrusion of debris during ultrasonic versus rotary instrumentation

    Directory of Open Access Journals (Sweden)

    Araquam, Karolline Rodrigues

    2009-01-01

    Full Text Available Objetivo: O objetivo deste estudo foi comparar a extrusão apical de debris durante a instrumentação rotatória versus ultra-sônica de canais radiculares. Metodologia: A amostra constituiu-se de 20 pré-molares inferiores com dimensões radiculares similares. Para coleta do material extruído apicalmente durante a instrumentação endodôntica, foram fixados recipientes de resina acrílica na superfície externa das raízes. Todos os dentes tiveram os terços cervical e médio dos canais radiculares preparado com brocas Gates-Glidden. Após odontometria, a instrumentação apical foi realizada com sistema ultra-sônico ou sistema rotatório (n=10/grupo. Os recipientes de resina foram pesados antes e após a instrumentação e a diferença de peso foi considerada a quantidade de material extruído. Os dados foram analisados por teste de Mann-Whitney, ao nível de significância de 0,05. Resultados: Houve grande variabilidade de quantidade de material extruído para ambas as técnicas de instrumentação, com valores de 0,0009 a 0,0860 g. Não houve diferença estatisticamente significante entre os dois grupos (P>0. 05. Conclusão: Pode-se concluir que ambas as técnicas de instrumentação testadas, com ultra-som ou sistema rotatório, apresentaram extrusão apical de debris em quantidade semelhante

  16. Frequency-dependent signal processing in apical dendrites of hippocampal CA1 pyramidal cells.

    Science.gov (United States)

    Watanabe, H; Tsubokawa, H; Tsukada, M; Aihara, T

    2014-10-10

    Depending on an animal's behavioral state, hippocampal CA1 pyramidal cells receive distinct patterns of excitatory and inhibitory synaptic inputs. The time-dependent changes in the frequencies of these inputs and the nonuniform distribution of voltage-gated channels lead to dynamic fluctuations in membrane conductance. In this study, using a whole-cell patch-clamp method, we attempted to record and analyze the frequency dependencies of membrane responsiveness in Wistar rat hippocampal CA1 pyramidal cells following noise current injection directly into dendrites and somata under pharmacological blockade of all synaptic inputs. To estimate the frequency-dependent properties of membrane potential, membrane impedance was determined from the voltage response divided by the input current in the frequency domain. The cell membrane of most neurons showed low-pass filtering properties in all regions. In particular, the properties were strongly expressed in the somata or proximal dendrites. Moreover, the data revealed nonuniform distribution of dendritic impedance, which was high in the intermediate segment of the apical dendritic shaft (∼220-260μm from the soma). The low-pass filtering properties in the apical dendrites were more enhanced by membrane depolarization than those in the somata. Coherence spectral analysis revealed high coherence between the input signal and the output voltage response in the theta-gamma frequency range, and large lags emerged in the distal dendrites in the gamma frequency range. Our results suggest that apical dendrites of hippocampal CA1 pyramidal cells integrate synaptic inputs according to the frequency components of the input signal along the dendritic segments receiving the inputs.

  17. [Use of root-end filling materials in a surgical apical endodontic treatment in the Netherlands

    OpenAIRE

    Bronkhorst, M.A.; Berge, S.J.; van Damme, P. A.; Borstlap, W.A.; Merkx, M.A.W.

    2008-01-01

    The material to be used for closing the root canal when carrying out a retrograde surgical apical endodontic treatment continues to be a subject of discussion. The aim of the present study was to inventory which materials are being used for this purpose at this moment by Dutch O&MF surgeons. All practicing Dutch OM&F surgeons (n = 195) were sent a questionnaire. The response rate was 77%. The results showed that at this moment intermediate restoration material (IRM) is the retrograde filling ...

  18. Cholesterol depletion of enterocytes. Effect on the Golgi complex and apical membrane trafficking

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, L L; Thorsen, Evy

    2000-01-01

    Intestinal brush border enzymes, including aminopeptidase N and sucrase-isomaltase, are associated with "rafts" (membrane microdomains rich in cholesterol and sphingoglycolipids). To assess the functional role of rafts in the present work, we studied the effect of cholesterol depletion on apical...... membrane trafficking in enterocytes. Cultured mucosal explants of pig small intestine were treated for 2 h with the cholesterol sequestering agent methyl-beta-cyclodextrin and lovastatin, an inhibitor of hydroxymethylglutaryl-coenzyme A reductase. The treatment reduced the cholesterol content >50...

  19. Evidence for an apical Na-Cl cotransporter involved in ion uptake in a teleost fish

    Science.gov (United States)

    Hiroi, J.; Yasumasu, S.; McCormick, S.D.; Hwang, P.-P.; Kaneko, T.

    2008-01-01

    Cation-chloride cotransporters, such as the Na+/K +/2Cl- cotransporter (NKCC) and Na+/Cl - cotransporter (NCC), are localized to the apical or basolateral plasma membranes of epithelial cells and are involved in active ion absorption or secretion. The objectives of this study were to clone and identify 'freshwater-type' and 'seawater-type' cation-chloride cotransporters of euryhaline Mozambique tilapia (Oreochromis mossambicus) and to determine their intracellular localization patterns within mitochondria-rich cells (MRCs). From tilapia gills, we cloned four full-length cDNAs homologous to human cation-chloride cotransporters and designated them as tilapia NKCC1a, NKCC1b, NKCC2 and NCC. Out of the four candidates, the mRNA encoding NKCC1a was highly expressed in the yolk-sac membrane and gills (sites of the MRC localization) of seawater-acclimatized fish, whereas the mRNA encoding NCC was exclusively expressed in the yolk-sac membrane and gills of freshwater-acclimatized fish. We then generated antibodies specific for tilapia NKCC1a and NCC and conducted whole-mount immunofluorescence staining for NKCC1a and NCC, together with Na+/K+-ATPase, cystic fibrosis transmembrane conductance regulator (CFTR) and Na+/H+ exchanger 3 (NHE3), on the yolk-sac membrane of tilapia embryos acclimatized to freshwater or seawater. The simultaneous quintuple-color immunofluorescence staining allowed us to classify MRCs clearly into four types: types I, II, III and IV. The NKCC1a immunoreactivity was localized to the basolateral membrane of seawater-specific type-IV MRCs, whereas the NCC immunoreactivity was restricted to the apical membrane of freshwater-specific type-II MRCs. Taking account of these data at the level of both mRNA and protein, we deduce that NKCC1a is the seawater-type cotransporter involved in ion secretion by type-IV MRCs and that NCC is the freshwater-type cotransporter involved in ion absorption by type-II MRCs. We propose a novel ion-uptake model by MRCs in

  20. [Abscess at the implant site following apical parodontitis. Hardware-related complications of deep brain stimulation].

    Science.gov (United States)

    Sixel-Döring, F; Trenkwalder, C; Kappus, C; Hellwig, D

    2006-08-01

    Deep brain stimulation of the subthalamic nucleus is an important treatment option for advanced stages of idiopathic Parkinson's disease, leading to significant improvement of motor symptoms in suited patients. Hardware-related complications such as technical malfunction, skin erosion, and infections however cause patient discomfort and additional expense. The patient presented here suffered a putrid infection of the impulse generator site following only local dental treatment of apical parodontitis. Therefore, prophylactic systemic antibiotic treatment is recommended for patients with implanted deep brain stimulation devices in case of operations, dental procedures, or infectious disease.

  1. Influence of the apical enlargement size on the endotoxin level reduction of dental root canals

    Directory of Open Access Journals (Sweden)

    Ariane Cassia Salustiano Marinho

    2012-12-01

    Full Text Available Gram-negative bacteria play an essential role in endodontic infections because they have virulence factors such as endotoxin. Due to its potential cytotoxic activity, special attention has been given to the removal/neutralization of this endotoxin in the root canal system. OBJECTIVE: The aim of this study was to evaluate the influence of the apical enlargement size (AES by using rotary instruments on the endotoxin level reduction of dental root canals. MATERIAL AND METHODS: Forty root canals of the mandibular premolar teeth were used. Escherichia coli endotoxin (055: B55 was inoculated into thirty root canals. Ten teeth served as the negative control group. After the incubation period, the first endotoxin samples were collected from the root canals with a sterile/apyrogenic paper point for the analysis of the endotoxin units (EU/mL present before instrumentation (S1. Specimen instrumentation was performed with the Mtwo® rotary system in the sequence 10/.04, 15/.05, 20/.06, 25/.06, 30/.05, 35/.04 and 40/.04. To monitor the effectiveness of increasing apical enlargement on endotoxin removal, the second endotoxin samples were collected from all the root canals after instrumentation with the following instruments: #25/.06- (S2; #30/.05- (S3; # 35/.04- (S4; and #40/.04- (S5. Limulus amebocyte lysate (LAL was used to quantify the levels of endotoxin. The results were statistically compared by using repeated measures of ANOVA with post hoc Tukey testing. RESULTS: Increasing levels of endotoxin removal was achieved by large sized apical enlargement: S2 (AES #25/.06- 89.2%, S3 (AES #30/.05- 95.9%, S4 (AES #35/.04- 97.8% and S5 (AES #40/.04- 98.2%. Substantial reduction of endotoxin content was obtained in S4 and S5 compared to S2 (p<0.05, however, the root canal preparation was not able to eliminate the endotoxin. CONCLUSIONS: Under the conditions of this study, it was concluded that the reduction of endotoxin levels of the dental root canals could be

  2. [Use of root-end filling materials in a surgical apical endodontic treatment in the Netherlands].

    Science.gov (United States)

    Bronkhorst, M A; Bergé, S J; Van Damme, Ph A; Borstlap, W A; Merkx, M A W

    2008-08-01

    The material to be used for closing the root canal when carrying out a retrograde surgical apical endodontic treatment continues to be a subject of discussion. The aim of the present study was to inventory which materials are being used for this purpose at this moment by Dutch O&MF surgeons. All practicing Dutch OM&F surgeons (n = 195) were sent a questionnaire. The response rate was 77%. The results showed that at this moment intermediate restoration material (IRM) is the retrograde filling material most widely used by the Dutch O&MF surgeons (47.6%) in cases of surgical apical endodontic treatment. Amalgam, with 35%, was second, especially due to its plasticity and convenience. The choice of material is just as often determined by tradition, personal preference, individual experience or scientific results. There seems to be no relationship between the dental surgeon's number of years of experience and the type of retro grade filling material which he or she uses.

  3. Mouse sperm acquire a new structure on the apical hook during epididymal maturation

    Institute of Scientific and Technical Information of China (English)

    Yi-Wen Lin; Tzu-Han Hsu; Pauline H Yen

    2013-01-01

    Spermatozoa emerging from the testis undergo a maturation process in the epididymis during which they change morphologically,biochemically and physiologically to gain motility and the ability to fertilize ova.We examined mouse epididymal sperm with immunostaining and transmission electron microscopy (EM) and identified a previously unknown structure on the apical hook.The structure has a coiled configuration around 11 nm in thickness and is present at the tip of each corner of the triangular-rod shaped perforatorium.Surveying sperm isolated from various regions of the epididymis indicated that mouse sperm acquire the hook rim (HR) structure during its passage through the proximal two-thirds of the caput epididymidis.The structure withstands vigorous sonication and harsh chemical treatments and remains intact after the acrosome reaction.Its location and sturdiness suggest a function in protecting the apical hook from mechanical wear during fertilization.Our EM images of epididymal sperm also revealed additional novel structures as well as lateral asymmetry of the sperm head,indicating that mouse sperm head has a structure more complex than previously recognized.

  4. Diabetes enhances dental caries and apical periodontitis in caries-susceptible WBN/KobSlc rats.

    Science.gov (United States)

    Kodama, Yasushi; Matsuura, Masahiro; Sano, Tomoya; Nakahara, Yutaka; Ozaki, Kiyokazu; Narama, Isao; Matsuura, Tetsuro

    2011-02-01

    Many epidemiologic studies have suggested that diabetes may be an important risk factor for periodontal disease. To determine whether diabetes induces or enhances periodontal disease or dental caries, dental tissue from diabetic male and nondiabetic female WBN/KobSlc rats and male and female age-matched nondiabetic F344 rats was analyzed morphologically and morphometrically for these 2 types of lesions. Soft X-ray examination revealed that the incidence and severity of both molar caries and alveolar bone resorption were much higher in male WBN/KobSlc rats with chronic diabetes than in nondiabetic female rats of the same strain. Histopathologic examination showed that dental caries progressed from acute to subacute inflammation due to bacterial infections and necrosis in the pulp when the caries penetrated the dentin. In the most advanced stage of dental caries, inflammatory changes caused root abscess and subsequent apical periodontitis, with the formation of granulation tissue around the dental root. Inflammatory changes resulted in resorption of alveolar bone and correlated well with the severity of molar caries. Our results suggest that diabetic conditions enhance dental caries in WBN/KobSlc rats and that periodontal lesions may result from the apical periodontitis that is secondary to dental caries.

  5. Apical transport of influenza A virus ribonucleoprotein requires Rab11-positive recycling endosome.

    Directory of Open Access Journals (Sweden)

    Fumitaka Momose

    Full Text Available Influenza A virus RNA genome exists as eight-segmented ribonucleoprotein complexes containing viral RNA polymerase and nucleoprotein (vRNPs. Packaging of vRNPs and virus budding take place at the apical plasma membrane (APM. However, little is known about the molecular mechanisms of apical transport of newly synthesized vRNP. Transfection of fluorescent-labeled antibody and subsequent live cell imaging revealed that punctate vRNP signals moved along microtubules rapidly but intermittently in both directions, suggestive of vesicle trafficking. Using a series of Rab family protein, we demonstrated that progeny vRNP localized to recycling endosome (RE in an active/GTP-bound Rab11-dependent manner. The vRNP interacted with Rab11 through viral RNA polymerase. The localization of vRNP to RE and subsequent accumulation to the APM were impaired by overexpression of Rab binding domains (RBD of Rab11 family interacting proteins (Rab11-FIPs. Similarly, no APM accumulation was observed by overexpression of class II Rab11-FIP mutants lacking RBD. These results suggest that the progeny vRNP makes use of Rab11-dependent RE machinery for APM trafficking.

  6. AmotL2 disrupts apical-basal cell polarity and promotes tumour invasion.

    Science.gov (United States)

    Mojallal, Mahdi; Zheng, Yujuan; Hultin, Sara; Audebert, Stéphane; van Harn, Tanja; Johnsson, Per; Lenander, Claes; Fritz, Nicolas; Mieth, Christin; Corcoran, Martin; Lembo, Frédérique; Hallström, Marja; Hartman, Johan; Mazure, Nathalie M; Weide, Thomas; Grandér, Dan; Borg, Jean-Paul; Uhlén, Per; Holmgren, Lars

    2014-08-01

    The establishment and maintenance of apical-basal cell polarity is essential for the functionality of glandular epithelia. Cell polarity is often lost in advanced tumours correlating with acquisition of invasive and malignant properties. Despite extensive knowledge regarding the formation and maintenance of polarity, the mechanisms that deregulate polarity in metastasizing cells remain to be fully characterized. Here we show that AmotL2 expression correlates with loss of tissue architecture in tumours from human breast and colon cancer patients. We further show that hypoxic stress results in activation of c-Fos-dependent expression of AmotL2 leading to loss of polarity. c-Fos/hypoxia-induced p60 AmotL2 interacts with the Crb3 and Par3 polarity complexes retaining them in large vesicles and preventing them from reaching the apical membrane. The resulting loss of polarity potentiates the response to invasive cues in vitro and in vivo in mice. These data provide a molecular mechanism how hypoxic stress deregulates cell polarity during tumour progression.

  7. Anatomy and histology of apical support: a literature review concerning cardinal and uterosacral ligaments.

    Science.gov (United States)

    Ramanah, Rajeev; Berger, Mitchell B; Parratte, Bernard M; DeLancey, John O L

    2012-11-01

    The objective of this work was to collect and summarize relevant literature on the anatomy, histology, and imaging of apical support of the upper vagina and the uterus provided by the cardinal (CL) and uterosacral (USL) ligaments. A literature search in English, French, and German languages was carried out with the keywords apical support, cardinal ligament, transverse cervical ligament, Mackenrodt ligament, parametrium, paracervix, retinaculum uteri, web, uterosacral ligament, and sacrouterine ligament in the PubMed database. Other relevant journal and textbook articles were sought by retrieving references cited in previous PubMed articles. Fifty references were examined in peer-reviewed journals and textbooks. The USL extends from the S2 to the S4 vertebra region to the dorsal margin of the uterine cervix and/or to the upper third of the posterior vaginal wall. It has a superficial and deep component. Autonomous nerve fibers are a major constituent of the deep USL. CL is defined as a perivascular sheath with a proximal insertion around the origin of the internal iliac artery and a distal insertion on the cervix and/or vagina. It is divided into a cranial (vascular) and a caudal (neural) portions. Histologically, it contains mainly vessels, with no distinct band of connective tissue. Both the deep USL and the caudal CL are closely related to the inferior hypogastric plexus. USL and CL are visceral ligaments, with mesentery-like structures containing vessels, nerves, connective tissue, and adipose tissue.

  8. Apical extrusion of debris by supplementary files used for retreatment: An ex vivo comparative study

    Directory of Open Access Journals (Sweden)

    Ajinkya M Pawar

    2016-01-01

    Full Text Available Aim: This study evaluated whether using supplementary files for removing root canal filling residues after ProTaper Universal Retreatment files (RFs increased the debris extrusion apically. Materials and Methods: Eighty mandibular premolars with single root and canal were instrumented with ProTaper Universal rotary system (SX-F3 and obturated. The samples were divided randomly into four groups (n = 20. Group 1 served as a control; only ProTaper Universal RFs D1-D3 were used, and the extruded debris was weighed. Groups 2, 3, and 4 were the experimental groups, receiving a twofold retreatment protocol: Removal of the bulk, followed by the use of supplementary files. The bulk was removed by RFs, followed by the use of ProTaper NEXT (PTN, WaveOne (WO, and Self-Adjusting File (SAF for removal of the remaining root filling residues. Debris extruded apically were weighed and compared to the control group. Statistical analysis was performed using one-way analysis of variance (ANOVA and post hoc Tukey′s test. Results: All the three experimental groups presented significant difference (P < .01. The post hoc Tukey′s test confirmed that Group 4 (SAF exhibited significantly less (P < .01 debris extrusion between the three groups tested. Conclusion: SAF results in less extrusion of debris when used as supplementary file to remove root-filling residues, compared to WO and PTN.

  9. Endodontic management of immature teeth with spontaneous apical closure and periapical lesions: case series and review of the literature.

    Science.gov (United States)

    Çalışkan, Mehmet Kemal; Kaval, Mehmet Emin

    2015-08-01

    Spontaneous apical closure in non-vital immature teeth has been rarely encountered and outcome of non-surgical endodontic treatment of related teeth associated with periapical lesions has not yet been adequately elucidated. The aim of this article was to report endodontic management of spontaneous apical closure of infected untreated immature teeth with periapical lesions and to review previously proposed mechanisms for the development of spontaneous hard tissue barrier. Three patients were referred at different time intervals to the endodontic clinic for treatment of their maxillary anterior incisors with acute or chronic apical periodontitis. Dental histories indicated that related teeth had been subjected to trauma approximately 12-18 years previously. Radiographically, the involved teeth exhibited incomplete root formation with spontaneous apical closure and were associated with an apical radiolucency. After biomechanical preparation, calcium hydroxide paste was applied and was changed once or twice within 3 months. All canals were then filled with gutta-percha and AH Plus and the follow-up period was 16-50 months; both clinical and radiographic examinations revealed adequate function, the absence of clinical symptoms and significant healing of the periapical radiolucency.

  10. The Water Permeability Reduction After Successive Hypo-Osmotic Shocks in Kidney Principal Cells is Apically Regulated

    Directory of Open Access Journals (Sweden)

    Liubov E. Katkova

    2014-11-01

    Full Text Available Background/Aims: Renal principal cells maintain their intracellular water and electrolyte content despite significant fluctuations of the extracellular water and salt concentrations. Their water permeability decreases rapidly (within a few seconds after successive hypo-osmotic shocks. Our aim was to investigate the contribution of the apical and basolateral surface to this effect and the potential influence of fast reduction in AQP-2, -3 or -4 plasma membrane content. Methods: Rat principal cells of kidney collecting duct fragments underwent hypo-osmotic challenge applied apically or basolaterally and the regulatory volume decrease (RVD was measured by the calcein quenching method. The AQP -2, -3 and -4 content of the plasma membrane fraction was quantified by Western blotting. Results: The hypo-osmotic shock applied apically causes rapid swelling with high apparent water permeability and fast RVD. An identical successive shock after 15-20 sec causes significantly lower swelling rate with 3-fold reduction in apparent water permeability. This reaction is accompanied by AQP2 decrease in the plasma membrane while AQP3 and AQP4 are unaffected. The contribution of the basolateral cell surface to RVD is significantly lower than the apical. Conclusion: These results indicate that in principal cells the effective mechanism of RVD is mainly regulated by the apical cell plasma membrane.

  11. Fragment Propagation and Colonization Ability Enhanced and Varied at Node Level after Escaping from Apical Dominance in Submerged Macrophytes

    Institute of Scientific and Technical Information of China (English)

    Jinhui Jiang; Shuqing An; Changfang Zhou; Baohua Guan; Zhiyi Sun; Ying Cai; Fude Liu

    2009-01-01

    Aquatic plants develop strong fragment propagation and colonization ability to endure the natural disturbances. However,detailed research of ability to endure the natural disturbances has been lacking to date. Therefore, reproduction (shoot) and colonization (root) of shoot fragments of Potamogeton crispus L. with or without apices were investigated for the effect of apical dominance, and the growth of decapitated shoot fragments at three lengths (2, 4, 6cm) was compared. Meanwhile,fragment propagation at levels of bud position was studied for bud position effect after escaping from apical dominance.The results showed significant increases occurred in the outgrowth of lateral branches on fragments decapitated compared with the fragments with apices, implying that apical dominance exists. Different lengths of fragments showed little difference in biomass allocations, but significant differences were noted in their propagation. Meanwhile, the effect of bud position was verified, due to the significant difference of average reproduction per node among the three length groups. Thus, the present study has made progress in the current understanding of aquatic plant dispersion among natural systems and contributes to improve methods of in vitro propagation for re-implantation purposes.

  12. Surgical closure of apical multiple muscular septal defects via right ventriculotomy using a single patch with intermediate fixings

    Institute of Scientific and Technical Information of China (English)

    LI Gang; WANG Qiang; LIU Ying-long; XU Yu-lin; GUO Yan

    2013-01-01

    Background Multiple apical muscular ventricular septal defects (VSDs) remain a challenge for surgeons because of their anatomical features.We used single patch with intermediate fixations to repair multiple apical muscular VSDs through right ventriculotomy.Methods We analysed the data of 16 children (median age 8 months,range 2 months to 144 months) with multiple apical muscular VSDs who underwent a single patch technique via apical right ventriculotomy.Perioperative data were collected and analysed,and the patients were followed up for three months to 66 months (median,46 months) to investigate the outcomes.Results All patients recovered from cardiopulmonary bypass easily with median of cardiopulmonary bypass time 87 minutes and of aortic crossclamp time 53 minutes.No surgically related death occurred and no patient required reoperation.One patient died of pseudomonas pyocyanea infection on day 11 postoperatively.Residual shunt happened in one patient with a diameter of 2 mm and spontaneously closed in 12 months after operation.Two patients presented slightly reduced right ventricular volume and apical hypokinesia postoperatively and recovered 24 and 36 months later respectively.No other complication was found during the three months to 66 months follow-up.Conclusion Our experiences using a single patch technique with intermediate fixations via right ventriculotomy in the management of multiple muscular VSDs had favourable outcomes.

  13. Morfologia e biometria do ligamento apical do pênis de touros da raça Girolando Morphology and biometry of the apical ligament of the penis of Girolando race bulls

    Directory of Open Access Journals (Sweden)

    Júlio Roquete Cardoso

    2010-08-01

    Full Text Available Objetivou-se descrever a morfologia e biometria do ligamento apical do pênis de 32 touros da raça Girolando (Bos taurus indicus X Bos taurus taurus, Linnaeus - 1758, com idade de 36 a 48 meses e pesando de 480 a 540kg. As peças anatômicas foram obtidas em frigorífico e mantidas congeladas até dissecação. O ligamento originou-se a 15,1±2,9cm distalmente à curvatura caudal da flexura sigmoide e inseriu-se a 1,4±0,7cm proximalmente ao colo da glande, medindo 18,9±2,6cm de comprimento. Apresentou largura de 1,9±0,6mm na sua origem, 2,2±0,8mm na inserção e 35,2±10mm na altura da inserção da lâmina interna do prepúcio. A espessura média ao longo de sua extensão variou de 0,7 a 1,9mm. Próximo à coroa da glande, o ligamento apical se posiciona principalmente na superfície dorsolateral esquerda desse órgão, e a característica da sua fixação na albugínea apresentou variações ao longo de sua extensão. Em sua origem e inserção e na face esquerda do pênis, o ligamento apical é firmemente aderido à túnica albugínea, mas na face dorsal e direita do pênis essa união é realizada por meio de tecido conjuntivo frouxo. Verificou-se correlação média entre o comprimento e a circunferência do pênis com o comprimento do ligamento apical, mas a correlação entre essas variáveis do pênis e a largura do ligamento apical foi baixa.The aim of this study was to describe the morphology and biometry of the apical ligament of the penis of Girolando bulls. For this purpose, it was dissected 32 penis of Girolando bulls obtained from slaughterhouses and kept frozen until their dissection. The animals were 36 to 48 month old and weighted between 480 and 540kg. The origin of the apical ligament occurred at 15.1±2.9cm distally to the caudal loop of the sigmoid flexure and its insertion occurred at 1.4±0.7cm proximally to the neck of the glans. The length of the apical ligament was 19.9±2.6cm. The width was 1.9±0.6mm at its

  14. Effect of diode laser irradiation on the apical sealing of MTA retrofillings Efeito da irradiação de laser de diodo no selamento apical em retrobturações com MTA

    Directory of Open Access Journals (Sweden)

    Eliana Barbosa de Souza

    2006-09-01

    Full Text Available Apical sealing is essential for the success of paraendodontic surgery, so any procedure that may favor an adequate sealing of the apical remainder should be performed. The purpose of this study was to evaluate the influence of diode laser irradiation on the apical sealing of root-end cavities with MTA retrofillings. Root canals in twenty extracted human teeth were shaped with K-files and filled with gutta-percha. The apexes were cut off and root-end preparations were performed. The roots were divided randomly in 2 groups. Group 1 (ten specimens was retrofilled with MTA. Group 2 was irradiated with diode laser, with 1 W for 20 seconds, on the apical surface and root end cavity before retrofilling with MTA. The specimens had their external surfaces impermeabilized with cyanoacrylate, except for the apical surface, and were then immersed in 1% rhodamine B dye for 72 h and placed in plaster stone. After that, the specimens were submitted to longitudinal abrasion until half of the root remained. The linear dye leakage was observed in these mid-roots between the root canal wall and retrofilling. The linear dye leakage was measured with Image Lab software, and the results were statistically analyzed with Student's t test. There were no statistically significant differences between the two groups (p > 0.05. The diode laser irradiation did not improve the apical sealing of MTA retrofillings under the conditions of this in vitro study.O selamento apical é fundamental para o sucesso da cirurgia parendodôntica. Assim, procedimentos que melhorem o selamento do remanescente apical devem ser utilizados. O objetivo deste estudo foi verificar se a irradiação de laser de diodo poderia aumentar o selamento apical em cavidades retrógradas obturadas com MTA. Foram utilizadas 20 raízes de dentes humanos extraídos que, após preparo com lima tipo K, tiveram seus canais obturados com guta-percha. Os ápices foram cortados e sofreram preparo de cavidades retr

  15. Evaluation of apical deviation in root canals instrumented with K3 and ProTaper systems Avaliação do desvio apical em canais instrumentados pelos sistemas K3 e ProTaper

    Directory of Open Access Journals (Sweden)

    Mariana Diniz Bisi dos Santos

    2006-12-01

    Full Text Available OBJECTIVES: this study evaluated the apical deviation of curved root canals instrumented with K3 and ProTaper systems. MATERIAL AND METHODS: twenty root canals of human maxillary and mandibular first molars were employed, which were divided into 2 groups: group A (10 teeth was instrumented with the K3 system, and group B (10 teeth with the ProTaper system. Evaluation of deviation was performed by double radiographic exposure. Radiographs were achieved before and after instrumentation, with 0.3-second, thus allowing superimposition of images. Three-dimensional computerized tomograph was performed in 3 specimens in each group, as an additional means to evaluate the apical deviation. RESULTS: were evaluated by the parametric test Student-Newman-Keuls at 5%, which did not reveal significance between groups concerning the apical deviation. The results of computerized tomograph images demonstrated that the larger deviation of the root canal occurred at the distolingual area for both systems. CONCLUSIONS: both techniques produced a mild apical deviation. Computerized microtomography was shown to be accurate for experimental endodontics studies.OBJETIVOS: avaliar o desvio apical de canais radiculares curvos instrumentados pelos sistemas K3 e ProTaper. MATERIAIS E MÉTODOS: foram utilizados 20 canais radiculares de primeiros molares superiores e inferiores humanos, os quais foram divididos em 2 grupos, o grupo A (10 dentes foi instrumentado pelo sistema K3 e o grupo B (10 dentes com o sistema ProTaper, a forma de avaliação do desvio foi a dupla exposição radiográfica. As tomadas radiográficas foram feitas antes e após a instrumentação, com um tempo de 0,3 segundos em cada exposição, ocorrendo assim, sobreposição das imagens. Em 3 espécimes, de cada grupo, foi realizada a tomografia computadorizada tridimensional, como forma adicional de avaliar o desvio apical . Os resultados obtidos foram avaliados pelo teste paramétrico Student

  16. Apical extrusion of debris after hand, engine-driven reciprocating and continuous preparation = Extrusão apical de “debris” após o preparo manual e mecanizado oscilatório e contínuo

    Directory of Open Access Journals (Sweden)

    Luisi, Simone Bonato

    2010-01-01

    Conclusão: A técnica rotatória contínua com Pro-taper produziu maior quantidade de extrusão apical do que as técnicas coroa-ápice manual e mecanizada com sistema de rotação oscilatória. A direção da instrumentação, se cérvico-apical ou ápico-cervical, parece ser o fator mais determinante na extrusão de “debris” independente desta ser realizada manual ou mecanizada

  17. Delayed-enhancement MRI of apical hypertrophic cardiomyopathy: assessment of the intramural distribution and comparison with clinical symptoms, ventricular arrhythmias, and cine MRI

    Energy Technology Data Exchange (ETDEWEB)

    Amano, Yasuo; Fukushima, Yoshimitsu; Kumita, Shinichiro (Dept. of Radiology, Nippon Medical School, Tokyo (Japan)), email: yas-amano@nifty.com; Takayama, Morimasa (Dept. of Cardiology, Sakakibara Heart Inst., Tokyo (Japan)); Kitamura, Mitsunobu (Coronary Care Unit, Chiba-Hokuso Hospital of Nippon Medical School, Chiba (Japan))

    2011-07-15

    Background: Hypertrophic cardiomyopathy (HCM) is reported to show patchy midwall myocardial hyper enhancement on delayed-enhancement magnetic resonance imaging (DE-MRI). The intramural distribution of myocardial hyper enhancement and its correlation with clinical symptoms, ventricular arrhythmias, and cardiac function have not been described for symptomatic apical HCM. Purpose: To evaluate the features and significance of myocardial hyper enhancement on DE-MRI in symptomatic apical HCM. Material and Methods: Thirteen patients with symptomatic apical HCM and their 65 apical segments were investigated. Myocardial hyper enhancement and regional and global functional parameters were determined with MRI. We investigated the intramural distribution and frequencies of this myocardial hyper enhancement and compared them with the patients' clinical symptoms, the presence of ventricular arrhythmias, and cine MRI. Results: Eight (61.5%) patients with symptomatic apical HCM displayed apical myocardial hyper enhancement, and 22 (33.8%) of the 65 apical segments examined showed myocardial hyper enhancement. Of the myocardial hyper enhancement observed, 81.8% showed a subendocardial pattern.The Hyperenhanced apical myocardium had a lower percentage of systolic myocardial thickening, and was associated with serious symptoms (e.g. syncope) and ventricular arrhythmias. Conclusion: Patients with symptomatic apical HCM showed myocardial hyper enhancement involving the subendocardial layer, which might be related to regional systolic dysfunction, serious clinical symptoms, and ventricular arrhythmias

  18. Irrigation dynamics associated with positive pressure, apical negative pressure and passive ultrasonic irrigations: a computational fluid dynamics analysis.

    Science.gov (United States)

    Chen, José Enrique; Nurbakhsh, Babak; Layton, Gillian; Bussmann, Markus; Kishen, Anil

    2014-08-01

    Complexities in root canal anatomy and surface adherent biofilm structures remain as challenges in endodontic disinfection. The ability of an irrigant to penetrate into the apical region of a canal, along with its interaction with the root canal walls, will aid in endodontic disinfection. The aim of this study was to qualitatively examine the irrigation dynamics of syringe irrigation with different needle tip designs (open-ended and closed-ended), apical negative pressure irrigation with the EndoVac® system, and passive ultrasonic-assisted irrigation, using a computational fluid dynamics model. Syringe-based irrigation with a side-vented needle showed a higher wall shear stress than the open-ended but was localised to a small region of the canal wall. The apical negative pressure mode of irrigation generated the lowest wall shear stress, while the passive-ultrasonic irrigation group showed the highest wall shear stress along with the greatest magnitude of velocity.

  19. Mid-ventricular obstructive hypertrophic cardiomyopathy with apical aneurysm and sustained ventricular tachycardia: a case report and literature review

    Institute of Scientific and Technical Information of China (English)

    GAO Xiao-jin; KANG Lian-ming; ZHANG Jian; DOU Ke-fei; YUAN Jian-song; YANG Yue-jin

    2011-01-01

    The case is a 54-year-old man with hypertrophic cardiomyopathy, mid-ventricular obstruction, apical aneurysm, and recurrence sustained monomorphic ventricular tachycardia (VT). A coronary angiogram revealed myocardial bridging located in the middle of the left anterior descending coronary artery (LAD), and the left ventriculogram showed an hour-glass appearance of the left ventricular cavity. There was a significant pressure gradient of 60 mmHg across the mid-ventricular obliteration at rest. A successful myectomy of the inappropriate hypertrophy myocardium and excision of the apical aneurysm were performed. Pathologic analysis demonstrated fibrosis in the apical aneurysm and thickened and narrowed vessels in the adjacent area. During the follow-up of eighteen months, the patient remained clinically stable and free from arrhythmic recurrence.

  20. The effect of irrigating solutions on the apical sealing ability of MTA Fillapex and Adseal root canal sealers

    Science.gov (United States)

    Singh, Richa; Pushpa, Shankarappa; Arunagiri, Doraiswamy; Sawhny, Asheesh; Misra, Abhinav; Sujatha, Ramamurthy

    2016-01-01

    Background. Maximum sealing ability or adhesion of endodontic sealers can be achieved after effective removal of the smear layer. Endodontic irrigants assist in adequate removal of the smear layer, improving the retention mechanism. The aim of this study was to evaluate the effect of two different root canal irrigation solutions (5.25% NaOCl followed by 17% EDTA and QMix) on the apical sealing ability of two different root canal sealers (MTA Fillapex and Adseal). Methods. Forty-six single-canal teeth were divided into 4 experimental groups of 10 teeth each and a positive and negative group of 3 teeth each. The root canals were prepared using step-back technique. The teeth in groups 1 and 2 were irrigated with 5.25% NaOCl followed by 17% EDTA and the teeth in groups 3 and 4 were irrigated with QMix. Finally all the teeth were flushed with sterile saline and dried using paper points. Obturation was accomplished by gutta-percha using lateral condensation technique. MTA Fillapex sealer was used in groups 1 and 3 whereas Adseal was used in groups 2 and 4. Dye penetration method was used to evaluate apical leakage. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests using SPSS 14. Statistical significance was set at P < 0.05. Results. Group 3 showed maximum amount of apical leakage (3.7±0.3 mm) whereas group 2 exhibited the least amount of apical leakage (2.1 ± 0.4 mm) among all the experimental groups. Significant differences were found in the amount of apical leakage between all the groups (P = 0.00001). Conclusion. Within the limitations of this study, 5.25% sodium hypochlorite followed by 17% EDTA and Adseal resulted in the best apical seal. PMID:28096952

  1. Age estimation in children by measurement of open apices in teeth with Bayesian calibration approach.

    Science.gov (United States)

    Cameriere, R; Pacifici, A; Pacifici, L; Polimeni, A; Federici, F; Cingolani, M; Ferrante, L

    2016-01-01

    Age estimation from teeth by radiological analysis, in both children and adolescents, has wide applications in several scientific and forensic fields. In 2006, Cameriere et al. proposed a regression method to estimate chronological age in children, according to measurements of open apices of permanent teeth. Although several regression models are used to analyze the relationship between age and dental development, one serious limitation is the unavoidable bias in age estimation when regression models are used. The aim of this paper is to develop a full Bayesian calibration method for age estimation in children according to the sum of open apices, S, of the seven left permanent mandibular teeth. This cross-sectional study included 2630 orthopantomographs (OPGs) from healthy living Italian subjects, aged between 4 and 17 years and with no obvious developmental abnormalities. All radiographs were in digital format and were processed by the ImageJ computer-aided drawing program. The distance between the inner side of the open apex was measured for each tooth. Dental maturity was then evaluated according to the sum of normalized open apices (S). Intra- and inter-observer agreement was satisfactory, according to an intra-class correlation coefficient of S on 50 randomly selected OPGs. Mean absolute errors were 0.72 years (standard deviation 0.60) and 0.73 years (standard deviation 0.61) in boys and girls, respectively. The mean interquartile range (MIQR) of the calibrating distribution was 1.37 years (standard deviation 0.46) and 1.51 years (standard deviation 0.52) in boys and girls, respectively. Estimate bias was βERR=-0.005 and 0.003 for boys and girls, corresponding to a bias of a few days for all individuals in the sample. Neither of the βERR values was significantly different from 0 (p>0.682). In conclusion, the Bayesian calibration method overcomes problems of bias in age estimation when regression models are used, and appears to be suitable for assessing both

  2. Nerve lesions following apical extrusion of non-setting calcium hydroxide: A systematic case review and report of two cases

    DEFF Research Database (Denmark)

    Olsen, Jesper Jared; Thorn, Jens Jørn; Korsgaard, Niels;

    2014-01-01

    We present two cases of apical extrusion of non-setting, calcium hydroxide paste which had been placed as an interappointment root canal dressing during routine endodontic treatment and which resulted in tissue necrosis of a large part of themandible, while. Surgical intervention consisted...... effects and the use of an injectable system had most often been related to apical extrusion. Consequently, great care should be taken when applying the paste into the canal system. 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved....

  3. Ultrastructure of the harmful unarmored dinoflagellate Cochlodinium polykrikoides (Dinophyceae) with reference to the apical groove and flagellar apparatus

    DEFF Research Database (Denmark)

    Iwataki, Mitsunori; Hansen, Gert; Moestrup, Øjvind;

    2010-01-01

    The external and internal ultrastructure of the harmful unarmored dinoflagellate Cochlodinium polykrikoides Margalef has been examined with special reference to the apical groove and three-dimensional structure of the flagellar apparatus. The apical groove is U-shaped and connected to the anterior...... sulcal extension on the dorsal side of the epicone. The eyespot is located dorsally and composed of two layers of globules situated within the chloroplast. A narrow invagination of the plasma membrane is associated with the eyespot. The nuclear envelope has normal nuclear pores similar to other...

  4. A comparison of apical sealing ability between GuttaFlow and AH plus: An in vitro study

    OpenAIRE

    Patil, Prajakta; Rathore, Vishnu P. S.; Hotkar, Chetan; Savgave, Snehal S.; K. Raghavendra; Ingale, Priya

    2016-01-01

    Aims: The present study aimed to compare apical sealing ability between GuttaFlow and AH Plus. Materials and Method: Eighty extracted human maxillary anterior teeth with fully formed apex and straight root were collected for this study. The root canals were cleaned and shaped using a standard step back preparation to size 60# master apical file at the established working length and divided into four groups: Group 1, GuttaFlow sealer with gutta-percha; Group 2, AH Plus sealer with gutta-percha...

  5. Apical regional wall motion abnormalities reminiscent to Tako-Tsubo cardiomyopathy following consumption of psychoactive fungi.

    Science.gov (United States)

    Nef, Holger M; Möllmann, Helge; Hilpert, Pirmin; Krause, Nicola; Troidl, Christian; Weber, Michael; Rolf, Andreas; Dill, Thorsten; Hamm, Christian; Elsässer, A

    2009-05-01

    Consumption of natural hallucinogenic substances continues to be a problem. In this case we report from a young male patient presenting with an acute coronary syndrome with significant ST-elevation after the abuse of psychoactive fungi, commonly referred to as "magic mushrooms". Coronary angiography excludes relevant coronary artery disease. In ventriculography contractile dysfunction with hypokinesia in the apical segments could be documented reminiscent to wall motion abnormalities in Tako-Tsubo cardiomyopathy (TTC). Cardiovascular magnetic resonance imaging showed no pathological signal activity in the late-enhancement sequences ruling out myocardial infarction or inflammatory processes. Ventricular function normalized within several days. The active metabolite of psychoactive fungi psilocybin is known to interact with several different dopaminergic, adrenergic and serotonergic receptors. Thus, the pathomechanisms leading to contractile dysfunction after consumption of psychoactive fungi are reminiscent to those documented in TTC.

  6. Rac1 controls epithelial tube length through the apical secretion and polarity pathways

    Directory of Open Access Journals (Sweden)

    Kévin Sollier

    2016-01-01

    Full Text Available The morphometric parameters of epithelial tubes are critical to the physiology and homeostasis of most organs. In addition, many human diseases are associated with tube-size defects. Here, we show that Rac1 limits epithelial tube elongation in the developing fly trachea by promoting Rab5-dependent endocytosis of the apical determinant Crumbs. Rac1 is also involved in a positive feedback loop with the septate junction protein Coracle. Thereby, Rac1 precludes paracellular diffusion and contributes to the septate junction-dependent secretion of the chitin-modifying enzymes Vermiform and Serpentine, which restrict epithelial tube length independently of Crumbs. Thus, Rac1 is a critical component of two important pathways controlling epithelial tube morphogenesis.

  7. Interventricular cardiac resynchronization with right ventricular apical pacing in a patient with Ebstein's defect.

    Science.gov (United States)

    Maffe, Stefano; Perucca, Antonello; Paffoni, Paola; Signorotti, Fabiana; Pardo, Nicolò Franchetti; Dellavesa, Pierfranco; Parravicini, Umberto; Zenone, Franco; Paino, Anna Maria; Bielli, Massimo; Carola, Federico; Zanetta, Marco

    2008-06-01

    We present the case of a patient with Ebstein's defect surgically corrected, and a complete right bundle branch block (RBBB) documented on echocardiogram. After an episode of near syncope due to a high-grade atrioventricular (AV) block, the patient was assisted with a bicameral DDDR pacemaker implanted with traditional right ventricular apical pacing. After the DDDR, and after stimulation with an AV delay of 180 ms, a narrow QRS complex was observed. Meanwhile, the typical left bundle branch block morphology of the right ventricular pacing and the native RBBB morphology were missing. The QRS complex narrowing persisted, even with physical activity and also with the heart rate progression. An echocardiographic study confirmed an improvement of the cardiac resynchronization parameters with this programmed stimulation.

  8. Rac1 controls epithelial tube length through the apical secretion and polarity pathways

    Science.gov (United States)

    Sollier, Kévin; Gaudé, Helori-Mael; Chartier, François J.-M.; Laprise, Patrick

    2016-01-01

    ABSTRACT The morphometric parameters of epithelial tubes are critical to the physiology and homeostasis of most organs. In addition, many human diseases are associated with tube-size defects. Here, we show that Rac1 limits epithelial tube elongation in the developing fly trachea by promoting Rab5-dependent endocytosis of the apical determinant Crumbs. Rac1 is also involved in a positive feedback loop with the septate junction protein Coracle. Thereby, Rac1 precludes paracellular diffusion and contributes to the septate junction-dependent secretion of the chitin-modifying enzymes Vermiform and Serpentine, which restrict epithelial tube length independently of Crumbs. Thus, Rac1 is a critical component of two important pathways controlling epithelial tube morphogenesis. PMID:26700724

  9. The Antituberculosis Drug Ethambutol Selectively Blocks Apical Growth in CMN Group Bacteria

    Science.gov (United States)

    Schubert, Karin; Sieger, Boris; Meyer, Fabian; Giacomelli, Giacomo; Böhm, Kati; Rieblinger, Angela; Lindenthal, Laura; Sachs, Nadja; Wanner, Gerhard

    2017-01-01

    ABSTRACT Members of the genus Mycobacterium are the most prevalent cause of infectious diseases. Mycobacteria have a complex cell envelope containing a peptidoglycan layer and an additional arabinogalactan polymer to which a mycolic acid bilayer is linked; this complex, multilayered cell wall composition (mAGP) is conserved among all CMN group bacteria. The arabinogalactan and mycolic acid synthesis pathways constitute effective drug targets for tuberculosis treatment. Ethambutol (EMB), a classical antituberculosis drug, inhibits the synthesis of the arabinose polymer. Although EMB acts bacteriostatically, its underlying molecular mechanism remains unclear. Here, we used Corynebacterium glutamicum and Mycobacterium phlei as model organisms to study the effects of EMB at the single-cell level. Our results demonstrate that EMB specifically blocks apical cell wall synthesis, but not cell division, explaining the bacteriostatic effect of EMB. Furthermore, the data suggest that members of the family Corynebacterineae have two dedicated machineries for cell elongation (elongasome) and cytokinesis (divisome). PMID:28174310

  10. Integration of light and metabolic signals for stem cell activation at the shoot apical meristem

    Science.gov (United States)

    Pfeiffer, Anne; Janocha, Denis; Dong, Yihan; Medzihradszky, Anna; Schöne, Stefanie; Daum, Gabor; Suzaki, Takuya; Forner, Joachim; Langenecker, Tobias; Rempel, Eugen; Schmid, Markus; Wirtz, Markus; Hell, Rüdiger; Lohmann, Jan U

    2016-01-01

    A major feature of embryogenesis is the specification of stem cell systems, but in contrast to the situation in most animals, plant stem cells remain quiescent until the postembryonic phase of development. Here, we dissect how light and metabolic signals are integrated to overcome stem cell dormancy at the shoot apical meristem. We show on the one hand that light is able to activate expression of the stem cell inducer WUSCHEL independently of photosynthesis and that this likely involves inter-regional cytokinin signaling. Metabolic signals, on the other hand, are transduced to the meristem through activation of the TARGET OF RAPAMYCIN (TOR) kinase. Surprisingly, TOR is also required for light signal dependent stem cell activation. Thus, the TOR kinase acts as a central integrator of light and metabolic signals and a key regulator of stem cell activation at the shoot apex. DOI: http://dx.doi.org/10.7554/eLife.17023.001 PMID:27400267

  11. Reverse or inverted apical ballooning in a case of refeeding syndrome.

    Science.gov (United States)

    Robles, Pablo; Monedero, Isabel; Rubio, Amador; Botas, Javier

    2015-06-26

    Takotsubo cardiomyopathy is characterized by the development of transient left ventricular regional wall motion abnormalities, in the absence of significant coronary artery obstruction. This syndrome usually occurs in women and is frequently associated with an intense emotional or physical stress. It usually involves apical segments, but in the recent years atypical forms have been described. Inverted or reverse Takotsubo is a variant in which the basal and midventricular segments are hypokinetic, sparing contractile function of the apex. In this report we describe the case of a 54-year-old woman, with chronic malnutrition, initially admitted because of hypoglycemia and severe electrolyte disturbance due to a refeeding syndrome. Within the next hours she experienced acute cardiac symptoms and developed heart failure with low cardiac output. Electrocardiogram (ECG), elevation of troponin and echocardiographic findings were consistent with inverted Takotsubo cardiomyopathy. To the best of our knowledge, this is the first incidence reported of inverted Takotsubo triggered by refeeding syndrome.

  12. Transcriptome profiling for discovery of genes involved in shoot apical meristem and flower development

    Directory of Open Access Journals (Sweden)

    Vikash K. Singh

    2014-12-01

    Full Text Available Flower development is one of the major developmental processes that governs seed setting in angiosperms. However, little is known about the molecular mechanisms underlying flower development in legumes. Employing RNA-seq for various stages of flower development and few vegetative tissues in chickpea, we identified differentially expressed genes in flower tissues/stages in comparison to vegetative tissues, which are related to various biological processes and molecular functions during flower development. Here, we provide details of experimental methods, RNA-seq data (available at Gene Expression Omnibus database under GSE42679 and analysis pipeline published by Singh and colleagues in the Plant Biotechnology Journal (Singh et al., 2013, along with additional analysis for discovery of genes involved in shoot apical meristem (SAM development. Our data provide a resource for exploring the complex molecular mechanisms underlying SAM and flower development and identification of gene targets for functional and applied genomics in legumes.

  13. Gingival recession following apical surgery in the esthetic zone: a clinical study with 70 cases

    DEFF Research Database (Denmark)

    von Arx, Thomas; Salvi, Giovanni E; Janner, Simone

    2009-01-01

    The present study evaluated gingival recession 1 year following apical surgery of 70 maxillary anterior teeth (central and lateral incisors, canines, and first premolars). A visual assessment of the mid-facial aspect of the gingival level and of papillary heights of treated teeth was carried out...... using photographs taken at pre-treatment and 1-year follow-up appointments. In addition, changes in the gingival margin (GM) and clinical attachment levels (CAL) were calculated with the use of clinical measurements, that is, pre-treatment and 1-year follow-up pocket probing depth and level of gingival...... margin. Changes in GM and CAL were then correlated with patient-, tooth-, and surgery-related parameters. The following parameters were found to significantly influence changes in GM and CAL over time: gingival biotype (P gingival recession than thick biotype...

  14. Pleiotropic patterning response to activation of Shh signaling in the limb apical ectodermal ridge.

    Science.gov (United States)

    Wang, Chi-Kuang Leo; Tsugane, Mizuyo H; Scranton, Victoria; Kosher, Robert A; Pierro, Louis J; Upholt, William B; Dealy, Caroline N

    2011-05-01

    Sonic hedgehog (Shh) signaling in the limb plays a central role in coordination of limb patterning and outgrowth. Shh expression in the limb is limited to the cells of the zone of polarizing activity (ZPA), located in posterior limb bud mesoderm. Shh is not expressed by limb ectoderm or apical ectodermal ridge (AER), but recent studies suggest a role for AER-Shh signaling in limb patterning. Here, we have examined the effects of activation of Shh signaling in the AER. We find that targeted expression of Shh in the AER activates constitutive Shh signaling throughout the AER and subjacent limb mesoderm, and causes a range of limb patterning defects with progressive severity from mild polydactyly, to polysyndactyly with proximal defects, to severe oligodactyly with phocomelia and partial limb ventralization. Our studies emphasize the importance of control of the timing, level and location of Shh pathway signaling for limb anterior-posterior, proximal-distal, and dorsal-ventral patterning.

  15. Management of immature teeth with apical infections using mineral trioxide aggregate

    Directory of Open Access Journals (Sweden)

    Sivakumar Nuvvula

    2010-01-01

    Full Text Available Traumatic injuries to the young permanent teeth lead to devitalization of the pulp with concomitant arrest in further development of the immature root of the involved tooth. Hermetic seal of the root canal system during obturation is not possible in such cases, due to the lack of an apical constriction. The traditional management technique in such cases has been apexification involving induction of a calcific barrier at the apex using calcium hydroxide, which in turn facilitates obturation of the root canal. However this becomes complicated when there is persistent infection leading to periapical changes. This case report describes the use of mineral trioxide aggregate (MTA for management of a periapically compromised immature tooth.

  16. Apical leakage in maxillary type IV premolars with three different endodontic treatments.

    Science.gov (United States)

    Staribratova-Reister, K; Reister, J P; Attin, T; Martus, P; Kielbassa, A M

    2003-09-01

    The aim of this study was to evaluate the sealing ability in orthogradely filled, apicoectomised and retrogradely filled maxillary premolars with two canals and two separate apical foramina. The root canals of 51 extracted maxillary premolars of type IV were uniformly shaped and filled by means of lateral condensation and subsequently randomly divided into three groups of 17 teeth each. The teeth of groups II and III received an apicoectomy. In group III an additional retrograde seal (Ketac Fil) was applied. Group I served as control. All specimens were immersed in a methylene blue solution for 24 h. The teeth were cross-sectioned and the maximal dye-penetration was measured. The significantly least dye-penetration was observed in group II (apicoectomy only), followed by group I and group III. The differences among all groups were statistically significant (pFil must be considered critically.

  17. CFTR chloride channel in the apical compartments: spatiotemporal coupling to its interacting partners.

    Science.gov (United States)

    Li, Chunying; Naren, Anjaparavanda P

    2010-04-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-regulated chloride channel located primarily at the apical or luminal surfaces of epithelial cells in the airway, intestine, pancreas, kidney, sweat gland, as well as male reproductive tract, where it plays a crucial role in transepithelial fluid homeostasis. CFTR dysfunction can be detrimental and may result in life-threatening disorders. CFTR hypofunctioning because of genetic defects leads to cystic fibrosis, the most common lethal genetic disease in Caucasians, whereas CFTR hyperfunctioning resulting from various infections evokes secretory diarrhea, the leading cause of mortality in early childhood. Therefore, maintaining a dynamic balance between CFTR up-regulating processes and CFTR down-regulating processes is essential for maintaining fluid and body homeostasis. Accumulating evidence suggests that protein-protein interactions play a critical role in the fine-tuned regulation of CFTR function. A growing number of proteins have been reported to interact directly or indirectly with CFTR chloride channel, suggesting that CFTR might be coupled spatially and temporally to a wide variety of interacting partners including ion channels, receptors, transporters, scaffolding proteins, enzyme molecules, signaling molecules, and effectors. Most interactions occur primarily between the opposing terminal tails (amino or carboxyl) of CFTR protein and its binding partners, either directly or mediated through various PDZ scaffolding proteins. These dynamic interactions impact the channel function, as well as localization and processing of CFTR protein within cells. This article reviews the most recent progress and findings about the interactions between CFTR and its binding partners through PDZ scaffolding proteins, as well as the spatiotemporal regulation of CFTR-containing macromolecular signaling complexes in the apical compartments of polarized cells lining the secretory epithelia.

  18. Influence of intracanal post on apical periodontitis identified by cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Estrela, Carlos; Porto, Olavo Cesar Lyra; Rodrigues, Cleomar Donizeth [Federal University of Goias (UFG), Goiania, GO (Brazil). Dental School; Bueno, Mike Reis [University of Cuiaba (UNIC), MT (Brazil). Dental School; Pecora, Jesus Djalma, E-mail: estrela3@terra.com.b [University of Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Dental School

    2009-07-01

    The determination of the success of endodontic treatment has been often discussed based on outcome obtained by periapical radiography. The aim of this study was to verify the influence of intracanal post on apical periodontitis detected by cone-beam computed tomography (CBCT). A consecutive sample of 1020 images (periapical radiographs and CBCT scans) taken from 619 patients (245 men; mean age, 50.1 years) between February 2008 and September 2009 were used in this study. Presence and intracanal post length (short, medium and long) were associated with apical periodontitis (AP). Chi-square test was used for statistical analyses. Significance level was set at p<0.01. The kappa value was used to assess examiner variability. From a total of 591 intracanal posts, AP was observed in 15.06%, 18.78% and 7.95% using periapical radiographs, into the different lengths, short, medium and long, respectively (p=0.466). Considering the same posts length it was verified AP in 24.20%, 26.40% and 11.84% observed by CBCT scans, respectively (p=0.154). From a total of 1,020 teeth used in this study, AP was detected in 397 (38.92%) by periapical radiography and in 614 (60.19%) by CBCT scans (p<0.001). The distribution of intracanal posts in different dental groups showed higher prevalence in maxillary anterior teeth (54.79%). Intracanal posts lengths did not influenced AP. AP was detected more frequently when CBCT method was used. (author)

  19. VEGFR-2 reduces while combined VEGFR-2 and -3 signaling increases inflammation in apical periodontitis

    Science.gov (United States)

    Virtej, Anca; Papadakou, Panagiota; Sasaki, Hajime; Bletsa, Athanasia; Berggreen, Ellen

    2016-01-01

    Background In apical periodontitis, oral pathogens provoke an inflammatory response in the apical area that induces bone resorptive lesions. In inflammation, angio- and lymphangiogenesis take place. Vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are key players in these processes and are expressed in immune cells and endothelial cells in the lesions. Objective We aimed at testing the role of VEGFR-2 and -3 in periapical lesion development and investigated their role in lymphangiogenesis in the draining lymph nodes. Design We induced lesions by pulp exposure in the lower first molars of C57BL/6 mice. The mice received IgG injections or blocking antibodies against VEGFR-2 (anti-R2), VEGFR-3 (anti-R3), or combined VEGFR-2 and -3, starting on day 0 until day 10 or 21 post-exposure. Results Lesions developed faster in the anti-R2 and anti-R3 group than in the control and anti-R2/R3 groups. In the anti-R2 group, a strong inflammatory response was found expressed as increased number of neutrophils and osteoclasts. A decreased level of pro-inflammatory cytokines was found in the anti-R2/R3 group. Lymphangiogenesis in the draining lymph nodes was inhibited after blocking of VEGFR-2 and/or -3, while the largest lymph node size was seen after anti-R2 treatment. Conclusions We demonstrate an anti-inflammatory effect of VEGFR-2 signaling in periapical lesions which seems to involve neutrophil regulation and is independent of angiogenesis. Combined signaling of VEGFR-2 and -3 has a pro-inflammatory effect. Lymph node lymphangiogenesis is promoted through activation of VEGFR-2 and/or VEGFR-3. PMID:27650043

  20. External apical root resorption in maxillary incisors in orthodontic patients: associated factors and radiographic evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Nanekrungsan, Kamonporn [Dept. of Dentistry, Overbrook Hospital, Chiang Rai (Thailand); Patanaporn, Virush; Janhom, Apirum; Korwanich, Narumanus [Dept. of Chiang Mai University, Chiang Mai (Thailand)

    2012-09-15

    This study was performed to evaluate the incidence and degree of external apical root resorption of maxillary incisors after orthodontic treatment and to evaluate particular associated factors related to external apical root resorption. The records and maxillary incisor periapical radiographs of 181 patients were investigated. Crown and root lengths were measured and compared on the pre- and post-treatment periapical radiographs. Crown length was measured from the center of the incisal edge to the midpoint of the cemento-enamel junction (CEJ). Root length was measured from the CEJ midpoint to the root apex. A correction factor for the enlargement difference was used to calculate root resorption. The periapical radiographs of 564 teeth showed that the average root resorption was 1.39{+-}1.27 (8.24{+-}7.22%) and 1.69{+-}1.14 mm (10.16{+-}6.78%) for the maxillary central and lateral incisors, respectively. The results showed that the dilacerated or pointed roots, maxillary premolar extraction cases, and treatment duration were highly significant factors for root resorption (p<0.001). Allergic condition was a significant factor at p<0.01. Age at the start of treatment, large overjet, and history of facial trauma were also factors significantly associated with root resorption (p<0.05). There was no statistically significant difference in root resorption among the factors of gender, overbite, tongue-thrusting habit, types of malocclusion, and types of bracket. These results suggested that orthodontic treatment should be carefully performed in pre-treatment extraction patients who have pointed or dilacerated roots and need long treatment duration.

  1. Apically extruded debris with three contemporary Ni-Ti instrumentation systems: An ex vivo comparative study

    Directory of Open Access Journals (Sweden)

    Logani Ajay

    2008-01-01

    Full Text Available Aim: To comparatively evaluate the amount of apically extruded debris when ProTaper hand, ProTaper rotary and ProFile systems were used for the instrumentation of root canals. Materials and Methods: Thirty minimally curved, mature, human mandibular premolars with single canals were randomly divided into three groups of ten teeth each. Each group was instrumented using one of the three instrumentation systems: ProTaper hand, ProTaper rotary and ProFile. Five milliliters of sterile water were used as an irrigant. Debris extruded was collected in preweighed polyethylene vials and the extruded irrigant was evaporated. The weight of the dry extruded debris was established by comparing the pre- and postinstrumentation weight of polyethylene vials for each group. Statistical Analysis: The Kruskal-Wallis nonparametric test and Mann-Whitney U test were applied to determine if significant differences existed among the groups ( P < 0.05. Results: All instruments tested produced a measurable amount of debris. No statistically significant difference was observed between ProTaper hand and ProFile system ( P > 0.05. Although ProTaper rotary extruded a relatively higher amount of debris, no statistically significant difference was observed between this type and the ProTaper hand instruments ( P > 0.05. The ProTaper rotary extruded significantly more amount of debris compared to the ProFile system ( P < 0.05. Conclusion: Within the limitations of this study, it can be concluded that all instruments tested produced apical extrusion of debris. The ProTaper rotary extruded a significantly higher amount of debris than the ProFile.

  2. A lesão apical em cardiopatas chagásicos crônicos: estudo necroscópico Apical lesions in Chagas' heart disease patients: an autopsy study

    Directory of Open Access Journals (Sweden)

    Cristina Brandt Friedrich Martin Gurgel

    2010-12-01

    Full Text Available INTRODUÇÃO: A lesão apical ventricular é típica da cardiopatia chagásica e sua presença representa risco de fenômenos tromboembólicos. O objetivo deste trabalho é avaliar a frequência de LA à necropsia de portadores de cardiopatia chagásica crônica. MÉTODOS: Análise retrospectiva de necropsias de chagásicos maiores que 17 anos. Efetuada análise estatística comparativa das variáveis clínicas e dos achados necroscópicos entre o grupo A (com lesão apical e o grupo B (ausência de lesão apical. RESULTADOS: Estudados 51 casos: 25 no grupo A (idade média de 53 anos, 64% do sexo masculinoe 26 no B.. A LA localizava-se no ventrículo esquerdo em 80% casos. No grupo B, a média de idade foi de 56 anos e 46,1% eram do sexo masculino. A forma clínica prevalente nos dois grupos foi a miopática, mas arritmia cardíaca também esteve presente em ambos (57,9% no grupo A e 32,1% no B. Foi constatada a presença de trombos em 60% dos casos do grupo A (53,3% localizados na LA e 30,7% no B; CONCLUSÕES: Houve predomínio da forma miopática nos casos com LA, com média de peso cardíaco maior em relação ao B. Em ambos os grupos observamos relação diretamente proporcional entre maior peso cardíaco e presença de tromboses. Houve predomínio do número de tromboses no grupo A, mais de 50% eram localizadas na lesão, cujo diferencial clínico principal consistiu na presença maior de arritmias. A miopatia (com aumento de peso acima de 500g foi primordial para aparecimento de tromboses.INTRODUCTION: The presence of an apical ventricular lesion increases the risk of intracardiac thrombosis and thromboembolic phenomena. The study evaluated the incidence of apical lesions and intracardiac thrombosis in Chagas' heart disease patients at autopsy. METHODS: A retrospective review of autopsies of Chagas' heart disease patients was conducted. Statistical analysis included comparison of clinical variables and autopsy findings between two groups

  3. A transferrin-like GPI-linked iron-binding protein in detergent-insoluble noncaveolar microdomains at the apical surface of fetal intestinal epithelial cells

    DEFF Research Database (Denmark)

    Danielsen, E M; van Deurs, B

    1995-01-01

    of ultracryosections of mucosal tissue, the protein was localized to the apical surface of the enterocytes, whereas it was absent from the basolateral plasma membrane. Interestingly, it was mainly found in patches of flat or invaginated apical membrane domains rather than at the surface of microvilli. Caveolae were...

  4. Does apical periodontitis have systemic consequences? The need for well-planned and carefully conducted clinical studies

    NARCIS (Netherlands)

    van der Waal, S.V.; Lappin, D.F.; Crielaard, W.

    2015-01-01

    Apical periodontitis, infection of the root canal system, may have systemic consequences. This proposal has been brought forward many times in dentistry literature but the general consensus is that there is no scientific basis for an association between endodontic infections and general health. This

  5. 5-year results comparing mineral trioxide aggregate and adhesive resin composite for root-end sealing in apical surgery

    DEFF Research Database (Denmark)

    von Arx, Thomas; Hänni, Stefan; Jensen, Simon Storgård

    2014-01-01

    INTRODUCTION: Recent meta-analyses of the outcome of apical surgery using modern techniques including microsurgical principles and high-power magnification have yielded higher rates of healing. However, the information is mainly based on 1- to 2-year follow-up data. The present prospective study ...

  6. The effect of apical preparation size on irrigant flow in root canals evaluated using an unsteady Computational Fluid Dynamics model

    NARCIS (Netherlands)

    Boutsioukis, C.; Gogos, C.; Verhaagen, B.; Versluis, M.; Kastrinakis, E.; van der Sluis, L.W.M.

    2010-01-01

    Aim  To evaluate the effect of apical preparation size on irrigant flow inside a root canal during final irrigation with a syringe and two different needles types, using a Computational Fluid Dynamics (CFD) model. Methodology  A validated CFD model was used to simulate the irrigant flow from either

  7. SUPPRESSOR OF APICAL DOMINANCE1 of Sporisorium reilianum Modulates Inflorescence Branching Architecture in Maize and Arabidopsis1[OPEN

    Science.gov (United States)

    Ghareeb, Hassan; Löfke, Christian; Teichmann, Thomas; Schirawski, Jan

    2015-01-01

    The biotrophic fungus Sporisorium reilianum causes head smut of maize (Zea mays) after systemic plant colonization. Symptoms include the formation of multiple female inflorescences at subapical nodes of the stalk because of loss of apical dominance. By deletion analysis of cluster 19-1, the largest genomic divergence cluster in S. reilianum, we identified a secreted fungal effector responsible for S. reilianum-induced loss of apical dominance, which we named SUPPRESSOR OF APICAL DOMINANCE1 (SAD1). SAD1 transcript levels were highly up-regulated during biotrophic fungal growth in all infected plant tissues. SAD1-green fluorescent protein fusion proteins expressed by recombinant S. reilianum localized to the extracellular hyphal space. Transgenic Arabidopsis (Arabidopsis thaliana)-expressing green fluorescent protein-SAD1 displayed an increased number of secondary rosette-leaf branches. This suggests that SAD1 manipulates inflorescence branching architecture in maize and Arabidopsis through a conserved pathway. Using a yeast (Saccharomyces cerevisiae) two-hybrid library of S. reilianum-infected maize tissues, we identified potential plant interaction partners that had a predicted function in ubiquitination, signaling, and nuclear processes. Presence of SAD1 led to an increase of the transcript levels of the auxin transporter PIN-FORMED1 in the root and a reduction of the branching regulator TEOSINTE BRANCHED1 in the stalk. This indicates a role of SAD1 in regulation of apical dominance by modulation of branching through increasing transcript levels of the auxin transporter PIN1 and derepression of bud outgrowth. PMID:26511912

  8. ION-EXCHANGE IMMUNOAFFINITY PURIFICATION OF A RECOMBINANT BACULOVIRUS PLASMODIUM-FALCIPARUM APICAL MEMBRANE ANTIGEN, PF83/AMA-1

    NARCIS (Netherlands)

    NARUM, DL; WELLING, GW; THOMAS, AW

    1993-01-01

    A two-step purification regime has been developed for a quantitatively minor, putatively transmembrane, M(r) 83 000, apical membrane blood stage vaccine candidate antigen of Plasmodium falciparum (PF83/AMA-1), that has been expressed as a full-length baculovirus recombinant protein, PF83-FG8-1. The

  9. Dopamine Induces LTP Differentially in Apical and Basal Dendrites through BDNF and Voltage-Dependent Calcium Channels

    Science.gov (United States)

    Navakkode, Sheeja; Sajikumar, Sreedharan; Korte, Martin; Soong, Tuck Wah

    2012-01-01

    The dopaminergic modulation of long-term potentiation (LTP) has been studied well, but the mechanism by which dopamine induces LTP (DA-LTP) in CA1 pyramidal neurons is unknown. Here, we report that DA-LTP in basal dendrites is dependent while in apical dendrites it is independent of activation of L-type voltage-gated calcium channels (VDCC).…

  10. MHV-A59 enters polarized murine epithelial cells through the apical surface but is released basolaterally

    NARCIS (Netherlands)

    Rossen, J W; Voorhout, W F; Horzinek, M C; van der Ende, A; Strous, G J; Rottier, P J

    1995-01-01

    Coronaviruses have a marked tropism for epithelial cells. Entry and release of the porcine transmissible gastroenteritis virus (TGEV) is restricted to apical surfaces of polarized epithelial cells, as we have recently shown (J. W. A. Rossen, C. P. J. Bekker, W. F. Voorhout, G. J. A. M. Strous, A. va

  11. Branching responses in Silphium integrifolium (Asteraceae) following mechanical or gall damage to apical meristems and neighbor removal.

    Science.gov (United States)

    Fay, Philip A; Throop, Heather L

    2005-06-01

    Branching in plants increases plant access to light and provides pathways for regrowth following damage or loss of the apical meristem. We conducted two experiments in an eastern Kansas tallgrass prairie to determine how apical meristem loss (by clipping), apical meristem damage (by insect galling), and increased light availability affected growth, reproduction, and branching in Silphium integrifolium (Asteraceae). The first experiment compared clipping with galling. Clipping increased axillary shoot numbers, while galling increased axillary shoot lengths, reflecting different allocation responses among damage types and inhibition of branching by galls. However, total capitulum production was less in all gall/clip treatments than in intact shoots. The second experiment compared clipping with mowing the surrounding vegetation to increase light availability. Mowing increased total leaf, total capitulum, and axillary shoot length and axillary capitulum production in clipped and unclipped plants and in large vs. small shoots. The presence of the neighboring canopy, not of an intact apical meristem, was therefore the stronger limitation on leaf and capitulum production. These experiments suggest that damage and light competition affected both branching frequency and the partitioning of resources among shoots, branches, and leaves. Because Silphium's growth form is widespread, similar responses may occur in other grassland forbs.

  12. Unique apicomplexan IMC sub-compartment proteins are early markers for apical polarity in the malaria parasite.

    Science.gov (United States)

    Poulin, Benoit; Patzewitz, Eva-Maria; Brady, Declan; Silvie, Olivier; Wright, Megan H; Ferguson, David J P; Wall, Richard J; Whipple, Sarah; Guttery, David S; Tate, Edward W; Wickstead, Bill; Holder, Anthony A; Tewari, Rita

    2013-01-01

    The phylum Apicomplexa comprises over 5000 intracellular protozoan parasites, including Plasmodium and Toxoplasma, that are clinically important pathogens affecting humans and livestock. Malaria parasites belonging to the genus Plasmodium possess a pellicle comprised of a plasmalemma and inner membrane complex (IMC), which is implicated in parasite motility and invasion. Using live cell imaging and reverse genetics in the rodent malaria model P. berghei, we localise two unique IMC sub-compartment proteins (ISPs) and examine their role in defining apical polarity during zygote (ookinete) development. We show that these proteins localise to the anterior apical end of the parasite where IMC organisation is initiated, and are expressed at all developmental stages, especially those that are invasive. Both ISP proteins are N-myristoylated, phosphorylated and membrane-bound. Gene disruption studies suggest that ISP1 is likely essential for parasite development, whereas ISP3 is not. However, an absence of ISP3 alters the apical localisation of ISP1 in all invasive stages including ookinetes and sporozoites, suggesting a coordinated function for these proteins in the organisation of apical polarity in the parasite.

  13. Inducción del cierre apical en el diente con necrosis pulpar y el ápice no formado

    OpenAIRE

    1988-01-01

    Se efectúa una revisión del proceso de apicoformación en dientes con necrosis pulpar y ápice no formado, analizando el mecanismo de cierre apical inducido por el hidróxido de calcio y otras substancias, así como la histopatología del mismo.

  14. Association of a peptoid ligand with the apical loop of pri-miR-21 inhibits cleavage by Drosha.

    Science.gov (United States)

    Diaz, Jason P; Chirayil, Rachel; Chirayil, Sara; Tom, Martin; Head, Katie J; Luebke, Kevin J

    2014-04-01

    We have found a small molecule that specifically inhibits cleavage of a precursor to the oncogenic miRNA, miR-21, by the microprocessor complex of Drosha and DGCR8. We identified novel ligands for the apical loop of this precursor from a screen of 14,024 N-substituted oligoglycines (peptoids) in a microarray format. Eight distinct compounds with specific affinity were obtained, three having affinities for the targeted loop in the low micromolar range and greater than 15-fold discrimination against a closely related hairpin. One of these compounds completely inhibits microprocessor cleavage of a miR-21 primary transcript at concentrations at which cleavage of another miRNA primary transcript, pri-miR-16, is little affected. The apical loop of pri-miR-21, placed in the context of pri-miR-16, is sufficient for inhibition of microprocessor cleavage by the peptoid. This compound also inhibits cleavage of pri-miR-21 containing the pri-miR-16 apical loop, suggesting an additional site of association within pri-miR-21. The reported peptoid is the first example of a small molecule that inhibits microprocessor cleavage by binding to the apical loop of a pri-miRNA.

  15. Unique apicomplexan IMC sub-compartment proteins are early markers for apical polarity in the malaria parasite

    Directory of Open Access Journals (Sweden)

    Benoit Poulin

    2013-09-01

    The phylum Apicomplexa comprises over 5000 intracellular protozoan parasites, including Plasmodium and Toxoplasma, that are clinically important pathogens affecting humans and livestock. Malaria parasites belonging to the genus Plasmodium possess a pellicle comprised of a plasmalemma and inner membrane complex (IMC, which is implicated in parasite motility and invasion. Using live cell imaging and reverse genetics in the rodent malaria model P. berghei, we localise two unique IMC sub-compartment proteins (ISPs and examine their role in defining apical polarity during zygote (ookinete development. We show that these proteins localise to the anterior apical end of the parasite where IMC organisation is initiated, and are expressed at all developmental stages, especially those that are invasive. Both ISP proteins are N-myristoylated, phosphorylated and membrane-bound. Gene disruption studies suggest that ISP1 is likely essential for parasite development, whereas ISP3 is not. However, an absence of ISP3 alters the apical localisation of ISP1 in all invasive stages including ookinetes and sporozoites, suggesting a coordinated function for these proteins in the organisation of apical polarity in the parasite.

  16. Apical extrusion of debris and irrigants using hand and three rotary instrumentation systems- An in vitro study

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    Koppolu Madhusudhana

    2010-01-01

    Full Text Available Introduction: Sterilization of the root canal is a prime aim of successful endodontics. The cleaning and shaping of the canal is directed as achieving this goal. The extrusion of apical debris has a deleterious effect on the prognosis of root canal treatment. Several instrument designs and instrumentation techniques have been developed to prevent this. Materials and Methods: Forty caries free single rooted human mandibular premolar teeth were divided in four groups of ten teeth each. Teeth in each group were instrumented until the working length with rotary ProTaper, K3, Mtwo systems, and hand K-type stainless steel files. Debris and irrigant extruded from the apical foramen were collected into vials and the amounts were quantitatively determined. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests. Results: The results show that all instrumentation techniques produced significant amount of extruded debris and irrigant. The engine-driven nickel-titanium systems showed less apical extrusion of debris and irrigant than manual technique. No statistically significant difference was found between the groups at [P > 0.05]. Maximum apical debris and irrigant extrusion was seen with K-file group and least in the Mtwo group. Conclusions: The use of rotary files and techniques to perform instrumentation does show less extrusion of the debris and irrigant from the apex. This can contribute to more successful endodontic therapy.

  17. Comparison of the amount of apical debris extrusion associated with different retreatment systems and supplementary file application during retreatment process

    Science.gov (United States)

    Çiçek, Ersan; Koçak, Mustafa Murat; Koçak, Sibel; Sağlam, Baran Can

    2016-01-01

    Background: The type of instrument affects the amount of debris extruded. The aim of this study was to compare the effect of retreatment systems and supplementary file application on the amount of apical debris extrusion. Materials and Methods: Forty-eight extracted mandibular premolars with a single canal and similar length were selected. The root canals were prepared with the ProTaper Universal system with a torque-controlled engine. The root canals were dried and were obturated using Gutta-percha and sealer. The specimens were randomly divided into four equal groups according to the retreatment procedures (Group 1, Mtwo retreatment files; Group 2, Mtwo retreatment files + Mtwo rotary file #30 supplementary file; Group 3, ProTaper Universal retreatment (PTUR) files; and Group 4, PTUR files + ProTaper F3 supplementary file). The extruded debris during instrumentation were collected into preweighed Eppendorf tubes. The amount of apically extruded debris was calculated by subtracting the initial weight of the tube from the final weight. Three consecutive weights were obtained for each tube. Results: No statistically significant difference was found in the amount of apically extruded debris between Groups 1 and 3 (P = 0.590). A significant difference was observed between Groups 1 and 2 (P < 0.05), and between Groups 3 and 4 (P < 0.05). Conclusions: The use of supplementary file significantly increased the amount of apically extruded debris. PMID:27563185

  18. Comparative evaluation of canal cleaning ability of various rotary endodontic filesin apical third: A scanning electron microscopic study

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    Jadhav, Ganesh Ranganath; Mittal, Priya; Kulkarni, Anish; Syed, Shibli; Bagul, Ravikiran; Elahi, Saina; Kalra, Dheeraj

    2016-01-01

    Background: The purpose of this study was to evaluate the canal cleaning ability of three novel endodontic rotary instruments and compare with ProTaper files as a control in apical third of root canals under scanning electron microscopy (SEM). Materials and Methods: Eighty freshly extracted mandibular premolars were selected according to inclusion criteria. Buccal cusp tips were ground to ensure having a flat coronal reference point with a total tooth length of 16 mm for all samples. Teeth were divided equally into four groups: Group I (ProTaper group), Group II (ProTaper next group), Group III (variable taper group), and Group IV (self-adjusting file [SAF] group). Using SEM, the dentinal surfaces were observed and rated at apical thirds with a magnification of ×1000 for the presence/absence of smear layer and debris. Descriptive analysis was performed, and analysis of variance with Bonferroni post hoc test was carried out for comparison between the groups, at a significance level of 0.05. Results: There was statistically significant difference between Group II and Group IV for debris (P = 0.047) and smear layer (P = 0.037). Conclusion: In apical third of root canal, SAF showed statistically significant canal cleaning ability due to combined effect of continuous streaming irrigation with effectively replacing the irrigant from the apical portion of the root canal, irrigants activation through the creation of turbulence, and its self-adapting design to root canal anatomy with a scrubbing motion on the canal walls. PMID:28182065

  19. Obstructor A Organizes Matrix Assembly at the Apical Cell Surface to Promote Enzymatic Cuticle Maturation in Drosophila*

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    Pesch, Yanina-Yasmin; Riedel, Dietmar; Behr, Matthias

    2015-01-01

    Assembly and maturation of the apical extracellular matrix (aECM) is crucial for protecting organisms, but underlying molecular mechanisms remain poorly understood. Epidermal cells secrete proteins and enzymes that assemble at the apical cell surface to provide epithelial integrity and stability during developmental growth and upon tissue damage. We analyzed molecular mechanisms of aECM assembly and identified the conserved chitin-binding protein Obst-A (Obstructor A) as an essential regulator. We show in Drosophila that Obst-A is required to coordinate protein and chitin matrix packaging at the apical cell surface during development. Secreted by epidermal cells, the Obst-A protein is specifically enriched in the apical assembly zone where matrix components are packaged into their highly ordered architecture. In obst-A null mutant larvae, the assembly zone is strongly diminished, resulting in severe disturbance of matrix scaffold organization and impaired aECM integrity. Furthermore, enzymes that support aECM stability are mislocalized. As a biological consequence, cuticle architecture, integrity, and function are disturbed in obst-A mutants, finally resulting in immediate lethality upon wounding. Our studies identify a new core organizing center, the assembly zone that controls aECM assembly at the apical cell surface. We propose a genetically conserved molecular mechanism by which Obst-A forms a matrix scaffold to coordinate trafficking and localization of proteins and enzymes in the newly deposited aECM. This mechanism is essential for maturation and stabilization of the aECM in a growing and remodeling epithelial tissue as an outermost barrier. PMID:25737451

  20. Estudio histopatológico de las reabsorciones cemento-dentinarias de la región apical de los dientes humanos extraídos con lesión crónica en el periapice A histopathology study of resorption cementum-dentin in the apical region of human teeth extracted chronic apical lesions

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    L Nunes da Rosa

    2003-04-01

    Full Text Available Veintiun dientes humanos extraídos con lesión crónica apical fueron analizados por la histopatología buscando determinar la presencia de la reabsorción cemento-dentinaria en la región periapical de estos dientes. En cada diente estudiado fue introducido un instrumento endodoncico para identificar el foramen apical y todos los dientes fueron radiografiados con una técnica estándar de película radiográfica periapical No. 2. Después de la descalcificación de los dientes, éstos fueron sometidos a la técnica histológica de rutina y evaluados histopatologicamente, observandose un diagnóstico de lesión apical y la presencia o no de re absorción y compensación cemento-dentinaria. De estas lesiones crónicas observadas, nueve eran cistos apicales, cinco granulomas y siete abscesos crónicos. De los veintiun dientes estudiados, veinte presentaron re absorción cementaria y diecisiete presentaron re absorción cemento-dentinaria.Twenty-one human teeth extracted with chronic apicallesions were analyzed histopathologically to determine the presence of resorptions of dentin and cementum in the apical region of these teeth. An endodontic file was introduced in each tooth for identification of the apical foramen and a roentgenography was taken with standard technique in number 2 xRay film. After decalcification the teeth were sectioned and only the apical third was analyzed. The teeth underwent the routine histological technic and histopathologically evaluated, the diagnosis of the chronic apicallesion and the presence or not of dentine and cementum resorption and compensation were observed. Nine of the chronic lesions observed were apical cysts, five granulomas and seven chronic abscesses. Out of twenty-one teeth analyzed, twenty teeth presented cementum resorption and seventeen presented dentine and cementum resorption.

  1. T1-nerve root neuroma presenting with apical mass and Horner's syndrome

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    Podnar Simon

    2007-03-01

    Full Text Available Abstract Background The appearance of dumbbell neuroma of the first thoracic root is extremely rare. The extradural component of a T1-dumbbell neuroma may present as an apical mass. The diagnosis of hand weakness is complex and may be delayed in T1-neuroma because of absence of the palpable cervical mass. One-stage removal of a T1-root neuroma and its intrathoracic extension demanded an extended posterior midline approach in the sitting position. Case presentation A 51-year old man had suffered a traumatic partial tendon rupture of his wrist flexor muscles 6 years ago. Since the incident he occasionally felt fullness and tenderness in the affected forearm with some tingling in his fingers bilaterally. During the last two years the hand weakness was continuous and hypotrophy of the medial flexor and intrinsic hand muscles had become apparent. Electrophysiological studies revealed an ulnar neuropathy in addition to mild median and radial nerve dysfunction, including a mild contralateral carpal tunnel syndrome. The diagnostic work-up for multiple mononeuropathy in the upper extremity was negative. Repeated electrophysiological studies revealed fibrillations in the C7 paravertebral muscles on the affected side. Chest x-ray revealed a large round apical mass on the affected side. A Horner's syndrome was noted at this point of diagnostic work-up. MRI of the cervical and thoracic spine revealed a dumbbell T1 neuroma enlarging the intervertebral foramen at T1-2 and a 5 cm large extradural tumor with extension into the apex of the ipsilateral lung. The patient underwent surgery in sitting position using a left dorsal midline approach. Although the T1 root could not be preserved, the patient's neurological condition was unchanged after the surgery. Conclusion Extended posterior midline exposure described here using hemilaminectomy, unilateral facetectomy and costo-transversectomy is efficient and safe for one-stage removal of dumbbell tumors at the T1

  2. Effect of different mixing and placement methods on the quality of MTA apical plug in simulated apexification model

    Science.gov (United States)

    Janani, Maryam; Razi, Tahmineh; Atharmoghaddam, Faezeh

    2017-01-01

    Background It is necessary apical plug material to exhibit proper adaptation with the root canal walls. Presence of voids at the interface between the root canal wall and this material result in micro leakage, which might have a relationship with post treatment disease. The aim of the present study was to evaluate the effect of different mixing (manual and ultrasonic) and placement (manual and manual in association with indirect ultrasonic) method of Mineral Trioxide Aggregate (MTA) on the void count and dimension in the apical plug in natural teeth with simulated open apices. Material and Methods Eighty human maxillary central incisors were selected. After simulation of the open apex model, the teeth were assigned to 4 groups based on the mixing and placement techniques of MTA: group 1, manual mixing and manual placement; group 2, manual mixing and manual placement in association with indirect ultrasonic; group 3, ultrasonic mixing and and manual placement; and group 4, ultrasonic mixing and manual placement in association with indirect ultrasonic. The prepared samples were placed within gypsum sockets in which the periodontal ligament was reconstructed with polyether impression material. In group 1, after mixing, the material was condensed with a hand plugger. In group 2, after mixing, the ultrasonic tip was contacted with the hand plugger for 2 seconds. In groups 3 and 4, mixing was carried out with the ultrasonic tip for 5 seconds and in groups 3 and 4, similar to groups 1 and 2, respectively, the materials were placed as apical plugs, measuring 3 mm in length. A wet cotton pellet was placed at canal orifices and dressed with Cavit. After one week, the cone beam computed tomography (CBCT) technique was used to count the number of voids between the material and root canal walls. The void dimensions were determined using the following scoring system: score 1, absence of voids; score 2, the void size less than half of the dimensions of the evaluated cross

  3. The Effect of Using Patency File on Apical Transportation in Canals Prepared with Passive Step Back Technique

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    S M Hasheminia

    2004-10-01

    Full Text Available Background: The purpose of this study was to assess the effect of patency file on apical transportation in curved canals prepared with passive step back (P.S.B technique. Methods: This is an interceptive experimental, Invitro, study. Human extracted first permanent molars with 19-23mm length and curvature of 15-35 degrees (Schneider method were considered for use in this study. Simple sampling was done and 35 teeth for each group was selected. In experimental group A canal preparation was done with P.S.B technique and usage of a # 10 file (as Patency file between successive files. In experimental group B preparation was done in the same way except for usage of patency file. Pre and post operative radiographs were taken with similar condition. Radiographs were scanned and changes in canal curvature was determined using four different methods [Schneider, Weine, Long – Axis techniques (L. A.T, and Digital image overlay technique (overlay. T] , using Idrisi for windows and AutoCAD softwares. Results: The mean of canal transportation angle in experimental group A with Schneider, Weine , LAT, and Over Lay techniques was: 7.006 ± 3.478, 12. 285 ± 6.032, 4.376 ± 3.516, 3.147 ± 2.744 respectively. Mean of canal transportation angle in experimental group B with the same methods was also determined: 8.009 ± 4.178, 13.55 ± 7.602, 9.464 ± 5.384, and 9.641 ± 5.382 respectively. T- test statistical analysis shows that there are no significant differences between the mean of canal transportation angles in two groups as measured by Schneider and Weine method (P>0.05. Mann- Whitney test shows that there are statistically significant differences between two groups as measured by LAT and Over Lay techniques (P<0.001. Conclusions: Results of this study shows that patency file in conjunction with P.S.B techniques causes significant reduction in apical transportation angle. Shortcomings of Schneider method in determination of canal curvature and specially

  4. Morphine Attenuates Apically-Directed Cytokine Secretion from Intestinal Epithelial Cells in Response to Enteric Pathogens

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    Amanda J. Brosnahan

    2014-04-01

    Full Text Available Epithelial cells represent the first line of host immune defense at mucosal surfaces. Although opioids appear to increase host susceptibility to infection, no studies have examined opioid effects on epithelial immune functions. We tested the hypothesis that morphine alters vectorial cytokine secretion from intestinal epithelial cell (IPEC-J2 monolayers in response to enteropathogens. Both entero-adherent Escherichia coli O157:H7 and entero-invasive Salmonella enterica serovar Typhimurium increased apically-directed IL-6 secretion and bi-directional IL-8 secretion from epithelial monolayers, but only IL-6 secretion evoked by E. coli was reduced by morphine acting through a naloxone-sensitive mechanism. Moreover, the respective type 4 and 5 Toll-like receptor agonists, lipopolysaccharide and flagellin, increased IL-8 secretion from monolayers, which was also attenuated by morphine pretreatment. These results suggest that morphine decreases cytokine secretion and potentially phagocyte migration and activation directed towards the mucosal surface; actions that could increase host susceptibility to some enteric infections.

  5. Folate receptor alpha is necessary for neural plate cell apical constriction during Xenopus neural tube formation.

    Science.gov (United States)

    Balashova, Olga A; Visina, Olesya; Borodinsky, Laura N

    2017-03-02

    Folate supplementation prevents up to 70% of neural tube defects (NTDs), which result from a failure of neural tube closure during embryogenesis. The elucidation of the mechanisms underlying folate action has been challenging. This study introduces Xenopus laevis as a model to determine the cellular and molecular mechanisms involved in folate action during neural tube formation. We show that knockdown of folate receptor-α (FRα) impairs neural tube formation and leads to NTDs. FRα knockdown in neural plate cells only is necessary and sufficient to induce NTDs. FRα-deficient neural plate cells fail to constrict, resulting in widening of the neural plate midline and defective neural tube closure. Pharmacological inhibition of folate action by methotrexate during neurulation induces NTDs by inhibiting folate interaction with its uptake systems. Our findings support a model for folate receptor interacting with cell adhesion molecules, thus regulating apical cell membrane remodeling and cytoskeletal dynamics necessary for neural plate folding. Further studies in this organism may unveil novel cellular and molecular events mediated by folate and lead to new means for preventing NTDs.

  6. Environmental and Pathogenic Factors Inducing Brown Apical Necrosis on Fruit of English (Persian) Walnut.

    Science.gov (United States)

    Scotton, Michele; Bortolin, Enrico; Fiorin, Antonio; Belisario, Alessandra

    2015-11-01

    Brown apical necrosis (BAN) is a most recently described disease affecting English (Persian) walnut fruit. BAN was only recorded in intensively managed walnut orchards and was found to be a disease complex mainly caused by Fusarium species. All fungi associated with this disease are polyphagous and ubiquitous, not specific to walnut. Consequently, BAN occurrence is more strictly dependent, than generally, on the interaction between pathological features and environmental conditions. Environmental variables identified with regression analysis showed that maximum temperature, angle of main wind direction versus tree row orientation, and orchard distance to the closest river/canal, all representative of climatic conditions occurring in the orchard, were related to fruit drop. The factor displaying the highest influence on severity of BAN fruit drop was maximum temperature and only subordinately factors are associated with relative humidity. BAN symptoms were reproduced with in planta artificial inoculation, and fruit drop of symptomatic fruit was significantly higher than that of the noninoculated trees for each type of inoculum (Fusarium semitectum, F. graminearum, and Alternaria spp.). F. semitectum and F. graminearum were more aggressive than Alternaria species, and the earliest artificial inoculations in mid-May resulted in the highest fruit drop. The extension of walnut fruit susceptibility and the conducive environmental factors to BAN are discussed.

  7. Comparison of External Apical Root Resorption after Orthodontic Treatment with Two Appliances (Standard Edgewise and MBT

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    V. Mollabashi

    2016-01-01

    Full Text Available Introduction & Objective: The aim of this study was todeterminetheamount of external apical root resorption(EARRwithin two orthodontic appliances (standard edgewise and MBT. Material & Methods In this retrospective study, panoramic radiographs of 83 orthodontic patients (27 male and 56 female were evaluated. 46 patients had been treated with standard edgewise appliance (29 patients with extraction and 17 patients without extraction and 37 patients had been treated with MBT appliance (27 patients with extraction and 10 patients without extraction.EARR were evaluated in 24 teeth (anterior teeth, premolars and first molars in each patient. SPSS software and ordinal regression test were used for statistical analysis. Result: In this study the most EARR was seen in upper lateral incisors, then lower lateral incisors.EARR in upper canines and lower second premolars was significantly related to extraction of first premolarin MBT appliance. In non extraction cases, EARR was not related to the orthodontic appliance. Conclusion: Incisors teeth are the most disposed teeth to EARR. Orthodontic treatment with extraction increased EARR in canines and second premolars. MBT appliance may increase EARR. Sci J Hamadan Univ Med Sci . 2016; 22 (4 :316-322

  8. Identification and characterization of Eimeria tenella apical membrane antigen-1 (AMA1.

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    Lianlian Jiang

    Full Text Available Apical membrane antigen-1 (AMA1 is a micronemal protein of apicomplexan parasites that appears to be essential during the invasion of host cells. In this study, a full-length cDNA of AMA1 was identified from Eimeria tenella (Et using expressed sequence tag and the rapid amplification of cDNA ends technique. EtAMA1 had an open reading frame of 1608 bp encoding a protein of 535 amino acids. Quantitative real-time PCR analysis revealed that EtAMA1 was expressed at higher levels in sporozoites than in the other developmental stages (unsporulated oocysts, sporulated oocysts and second-generation merozoites. The ectodomain sequence was expressed as recombinant EtAMA1 (rEtAMA1 and rabbit polyclonal antibodies raised against the rEtAMA1 recognized a 58-kDa native parasite protein by Western Blotting and had a potent inhibitory effect on parasite invasion, decreasing it by approximately 70%. Immunofluorescence analysis and immunohistochemistry analysis showed EtAMA1 might play an important role in sporozoite invasion and development.

  9. [Cytogenetic effects of toxic metal salts on apical meristem cells of Allium cepa L. seed roots].

    Science.gov (United States)

    Dovgaliuk, A I; Kaliniak, T B; Blium, Ia B

    2001-01-01

    Comparative analysis of the influence of the salts of Cd, Pb, Ni, Al, Cu and Zn at concentrations 10(-6)-10(-3) M on cytogenetic parameters of Allium cepa apical meristem cells was carried out. It was shown that these metal compounds could induce both the clastogenic and the aneugenic effects (including mitosis and cytokinesis disturbances). Based on ability to cause the chromosome aberrations the metal salts were arranged in such row of genotoxicity: ZnSO4 > Pb(CH3COO)2 > Al(NO3)3 approximately NiSO4 > CdCl2 > CuSO4. The investigated compounds of cadmium, lead, nickel and aluminum were found to be more effective aneugens than clastogens. According to our data NiSO4 had the strongest antimitotic activity (it increased the percentage of chromosome lagging of, multipolar anaphases, C-mitoses in 69.6 times, compared to the control). The ability of other metal salts to induce such abnormalities decreased in the range: CdCl2 > Al(NO3)3 > Pb(CH3COO)2 > CuSO4 > ZnSO4. Increasing of binuclear cells on the slides was revealed after treatment by all tested substances, however Ni sulfate was found as the strongest inducer of cytokinesis abnormalities. Presented results allowed to suggest that cytoskeleton could be a cell target for salts of some metals (especially for NiSO4).

  10. A membrane fusion protein αSNAP is a novel regulator of epithelial apical junctions.

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    Nayden G Naydenov

    Full Text Available Tight junctions (TJs and adherens junctions (AJs are key determinants of the structure and permeability of epithelial barriers. Although exocytic delivery to the cell surface is crucial for junctional assembly, little is known about the mechanisms controlling TJ and AJ exocytosis. This study was aimed at investigating whether a key mediator of exocytosis, soluble N-ethylmaleimide sensitive factor (NSF attachment protein alpha (αSNAP, regulates epithelial junctions. αSNAP was enriched at apical junctions in SK-CO15 and T84 colonic epithelial cells and in normal human intestinal mucosa. siRNA-mediated knockdown of αSNAP inhibited AJ/TJ assembly and establishment of the paracellular barrier in SK-CO15 cells, which was accompanied by a significant down-regulation of p120-catenin and E-cadherin expression. A selective depletion of p120 catenin effectively disrupted AJ and TJ structure and compromised the epithelial barrier. However, overexpression of p120 catenin did not rescue the defects of junctional structure and permeability caused by αSNAP knockdown thereby suggesting the involvement of additional mechanisms. Such mechanisms did not depend on NSF functions or induction of cell death, but were associated with disruption of the Golgi complex and down-regulation of a Golgi-associated guanidine nucleotide exchange factor, GBF1. These findings suggest novel roles for αSNAP in promoting the formation of epithelial AJs and TJs by controlling Golgi-dependent expression and trafficking of junctional proteins.

  11. Variations of growth in shoot apical domes of spruce seedlings: A study using the growth tensor

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    Jerzy Nakielski

    2014-02-01

    Full Text Available Variations of the relative elemental rate of growth within apical domes, for the case when dome geometry changes during development, were modeled. It was ascertained that: 1 the domes of spruce seedlings have a paraboloidal shape; 2 the shape is maintained during growth, but the domes become higher and wider; 3 the relative elemental rate of growth in area on dome surface is isotropic, as indicated by analysis of cell packets in the surface layer. These data were used in modeling by means of the growth tensor and natural coordinate system. Growth of the dome was considered a superposition: 1 of relatively fast steady shape growth, where the isotropy of growth in area on the surface of the dome, was determined, and 2 of relatively slow isogonic growth, which does not disturb the isotropy. The convergent parabolic system was selected as the natural coordinate system. Distributions of the growth rates in the form of computer-made maps for three domes differing in age, were obtained. It appears that the growth rates within the dome are relatively high in the distal part and smaller in the central and peripheral regions. This variation decreases progressively with seedling age when the dome becomes wider. The relative elemental rate of growth in volume, averaged for the whole dome, also decreases.

  12. Phenotypical and structural characterization of the Arabidopsis mutant involved in shoot apical meristem

    Institute of Scientific and Technical Information of China (English)

    Zhe HU; Ping LI; Jinfang MA; Yunlong WANG; Xinyu WANG; Chongying WANG

    2008-01-01

    An Arabidopsis mutant induced by T-DNA insertion was studied with respect to its phenotype, micro-structure of shoot apical meristem (SAM) and histo-chemical localization of the GUS gene in comparison with the wild type. Phenotypical observation found that the mutant exhibited a dwarf phenotype with smaller organs (such as smaller leaves, shorter petioles), and slower development and flowering time compared to the wild type. Optical microscopic analysis of the mutant showed that it had a smaller and more flattened SAM, with reduced cell layers and a shortened distance between two leaf primordia compared with the wild type. In addi-tion, analysis of the histo-chemical localization of the GUS gene revealed that it was specifically expressed in the SAM and the vascular tissue of the mutant, which suggests that the gene trapped by T-DNA may function in the SAM, and T-DNA insertion could influence the functional activity of the related gene in the mutant, lead-ing to alterations in the SAM and a series of phenotypes in the mutant.

  13. Reverse or inverted apical ballooning in a case of refeeding syndrome

    Institute of Scientific and Technical Information of China (English)

    Pablo; Robles; Isabel; Monedero; Amador; Rubio; Javier; Botas

    2015-01-01

    Takotsubo cardiomyopathy is characterized by the development of transient left ventricular regional wall motion abnormalities,in the absence of significant coronary artery obstruction. This syndrome usually occurs in women and is frequently associated with an intense emotional or physical stress. It usually involves apical segments,but in the recent years atypical forms have been described. Inverted or reverse Takotsubo is a variant in which the basal and midventricular segments are hypokinetic,sparing contractile function of the apex. In this report we describe the case of a 54-year-old woman,with chronic malnutrition,initially admitted because of hypoglycemia and severe electrolyte disturbance due to a refeeding syndrome. Within the next hours she experienced acute cardiac symptoms and developed heart failure with low cardiac output. Electrocardiogram(ECG),elevation of troponin and echocardiographic findings were consistent with inverted Takotsubo cardiomyopathy. To the best of our knowledge,this is the first incidence reported of inverted Takotsubo triggered by refeeding syndrome.

  14. Comparing and studying crack formation during apical cavity preparation using ultrasonic instruments

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    Zarrabian M.

    1999-07-01

    Full Text Available One of the major goals of periradicular surgery is to create a good apical sea! at the apex. This"nis done by sectioning of 2 to 3mm from the apex, preparation of a class I cavity and filling with a"nbiocompatible material."nThe purpose of this in vitro study was to determine whether ultrasonic units used for root end"npreparations could change the surface & structure of resected root ends, as competed to common"nmethods of retropreparation. Eighty-five extracted single rooted teeth were divided into five similar"ngroups. Then instrumented and filled with lateral condensation method. Then three millimeter of apex"nwas resected, retropreparaiions in two groups were done with low speed handpiece and round V ^ur"nand cavities in two other groups prepared with the highest power of dentspiay ultrasonic unit with TFI-"n10 tip and in one other group prepared with the highest power of neo sonic ultrasonic unit with diamond"ncoated CT-1 retro tip."nFollowing root resection and retropreparation the surface of resected root ends were examined for the"npresence of any cracks or structural changes on the surface of resected root ends with stereo microscope"n50x."nThe results of this study showed thai high power settings of ultrasonic units can increase the potential of"ncrack formation on resected root surfaces. In conclusion it is better to use low power setting of ultrasonic"nfor retropreparation.

  15. The mitochondrial protease AtFTSH4 safeguards Arabidopsis shoot apical meristem function.

    Science.gov (United States)

    Dolzblasz, Alicja; Smakowska, Elwira; Gola, Edyta M; Sokołowska, Katarzyna; Kicia, Marta; Janska, Hanna

    2016-06-20

    The shoot apical meristem (SAM) ensures continuous plant growth and organogenesis. In LD 30 °C, plants lacking AtFTSH4, an ATP-dependent mitochondrial protease that counteracts accumulation of internal oxidative stress, exhibit a puzzling phenotype of premature SAM termination. We aimed to elucidate the underlying cellular and molecular processes that link AtFTSH4 with SAM arrest. We studied AtFTSH4 expression, internal oxidative stress accumulation, and SAM morphology. Directly in the SAM we analysed H2O2 accumulation, mitochondria behaviour, and identity of stem cells using WUS/CLV3 expression. AtFTSH4 was expressed in proliferating tissues, particularly during the reproductive phase. In the mutant, SAM, in which internal oxidative stress accumulates predominantly at 30 °C, lost its meristematic fate. This process was progressive and stage-specific. Premature meristem termination was associated with an expansion in SAM area, where mitochondria lost their functionality. All these effects destabilised the identity of the stem cells. SAM termination in ftsh4 mutants is caused both by internal oxidative stress accumulation with time/age and by the tissue-specific role of AtFTSH4 around the flowering transition. Maintaining mitochondria functionality within the SAM, dependent on AtFTSH4, is vital to preserving stem cell activity throughout development.

  16. Poorly selective cation channels in the apical membrane of A6 cells.

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    Van Driessche, W; De Smet, P; de Smedt, H

    1994-03-01

    This paper describes a Ca(2+)-blockable, poorly selective cation pathway in the apical membrane of A6 epithelia. This pathway has properties that resemble the cation-selective channels in the toad urinary bladder and frog skin. Transepithelial short circuit currents (Isc) and power density spectra (PDS) of the fluctuations in current were recorded. The basolateral surface of the tissues was exposed to Cl- or SO4(2-) solutions with Na+ as the major cation. Ca(2+)-blockable inward oriented currents and Lorentzian noise were recorded with isotonic (215 mosmol/kg) mucosal Cl- and hypotonic (144 mos-mol/kg serosal SO4(2-) solution with Na+, K+, Rb+ or Cs+ as the major mucosal cation. Experiments with mucosal K+ demonstrated that the cation-selective channel was markedly activated by serosal hypotonicity. Effects of an increased electrical driving force were excluded on the basis of the results obtained with microelectrode experiments and transepithelial voltage clamping. Cell volume expansion induced by isotonic replacements of serosal sucrose by glycerol or urea also activated the cation-selective pathway. Furthermore, the presence of Cl- in the mucosal solution was a prerequisite for a sustained response to hypotonicity or replacements of the organic compounds. Moreover, we found that the cation-selective channels are mainly expressed in the cells during the early period of epithelial growth.

  17. The role of hormone transport and metabolism in apical dominance in oats

    Science.gov (United States)

    Harrison, M. A.; Kaufman, P. B.

    1984-01-01

    14C-benzyladenine (BA) and 14C-indole-3-acetic acid (IAA) were used to study hormone transport to the tiller bud and hormone catabolism in excised oat stem segments. Acropetal BA transport was greatest from upright stem segments to tiller buds suppressed by apical dominance. IAA, abscisic acid (ABA), and C2H4 inhibited BA transport to the tiller bud. IAA transport to the tiller bud site was inhibited by BA, C2H4, or after gravistimulation, which affected BA transport to a lesser extent than IAA transport. Multiple peaks of radioactivity were observed in 14C-BA- or 14C-IAA-treated stem segments after 9 h of transport. IAA, ABA, and C2H4 promoted BA catabolism. Auxin, ABA, and C2H4 may inhibit tiller bud release by inhibiting cytokinin transport to the tiller bud and by promoting cytokinin catabolism. Gravistimulation may promote tiller release by inhibiting IAA transport to the tiller bud and allowing cytokinins to accumulate there preferentially.

  18. Deviations from Scaling Symmetry in the Apical Half of the Human Cochlea

    Science.gov (United States)

    Abdala, Carolina; Dhar, Sumitrajit; Kalluri, Radha

    2012-01-01

    Invariant distortion product otoacoustic emission (DPOAE) phase elucidates scaling symmetry in the cochlea. Below some low-frequency boundary, DPOAE phase slope steepens. The origin of this break in phase invariance is not clear. Stimulus frequency (SF)OAE delays computed from the slope of phase also manifest discontinuities at low frequencies, though the relationship between the breaking of cochlear scaling as defined by SFOAE and DPOAE metrics has not been examined. In this study, OAEs were recorded in normal-hearing human adults to probe cochlear scaling and its breaking and to examine the correspondence between two OAE metrics of scaling. Results indicate: (1) the apical break in DPOAE phase invariance cannot be explained by contributions from the reflection-source component; (2) DPOAE phase signals a break from scaling near 1.5 kHz and (3) DPOAE and SFOAE metrics of cochlear scaling produce phase discontinuities within approximately one-quarter octave of each other and show comparable rates of breaking, suggesting a common underlying origin. PMID:22745514

  19. Dental age estimation of growing children by measurement of open apices: A Malaysian formula

    Directory of Open Access Journals (Sweden)

    Navaneetha Cugati

    2015-01-01

    Full Text Available Background: Age estimation is of prime importance in forensic science and clinical dentistry. Age estimation based on teeth development is one reliable approach. Many radiographic methods are proposed on the Western population for estimating dental age, and a similar assessment was found to be inadequate in Malaysian population. Hence, this study aims at formulating a regression model for dental age estimation in Malaysian children population using Cameriere′s method. Materials and Methods: Orthopantomographs of 421 Malaysian children aged between 5 and 16 years involving all the three ethnic origins were digitalized and analyzed using Cameriere′s method of age estimation. The subjects′ age was modeled as a function of the morphological variables, gender (g, ethnicity, sum of normalized open apices (s, number of tooth with completed root formation (N 0 and the first-order interaction between s and N 0 . Results: The variables that contributed significantly to the fit were included in the regression model, yielding the following formula: Age = 11.368-0.345g + 0.553N o -1.096s - 0.380s.N o , where g is a variable, 1 for males and 2 for females. The equation explained 87.1% of total deviance. Conclusion: The results obtained insist on reframing the original Cameriere′s formula to suit the population of the nation specifically. Further studies are to be conducted to evaluate the applicability of this formula on a larger sample size.

  20. Analysis of apical deviation by type of system used to drive NRT® MANI rotary instruments

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    Elise Sasso Faccin

    2014-01-01

    Full Text Available Purpose: One of the major challenges encountered in treatment of curved canals is maintaining their original features. This study aimed to examine whether the type of system used with NRT® rotary instruments might in fl uence the occurrence of deviation in the apical region. Methods: Twenty simulated curved canals were divided into two experimental groups. In Group 1, canal preparation was performed with the pneumatic hand piece, using constant speed, but without torque control. In Group 2, an electric motor with constant speed and torque control was used. The simulated blocks were photographed before and after preparation using a platform to maintain the same position in both photographs. Images were manipulated in Adobe Photoshop® to evaluate deviation at 1 mm and 3 mm from the working length (WL. The t test was used for statistical analysis of data. The signi fi cance level was set at 1%. Results and Conclusion: Group 2 (electric motor had lower values for deviation at both locations analyzed (1 mm and 3 mm from the WL. In both groups, sites 3 mm from the WL had lower mean deviation than sites 1 mm from WL.

  1. Characterization of a novel inhibitory human monoclonal antibody directed against Plasmodium falciparum Apical Membrane Antigen 1.

    Science.gov (United States)

    Maskus, Dominika J; Królik, Michał; Bethke, Susanne; Spiegel, Holger; Kapelski, Stephanie; Seidel, Melanie; Addai-Mensah, Otchere; Reimann, Andreas; Klockenbring, Torsten; Barth, Stefan; Fischer, Rainer; Fendel, Rolf

    2016-12-21

    Malaria remains a major challenge to global health causing extensive morbidity and mortality. Yet, there is no efficient vaccine and the immune response remains incompletely understood. Apical Membrane Antigen 1 (AMA1), a leading vaccine candidate, plays a key role during merozoite invasion into erythrocytes by interacting with Rhoptry Neck Protein 2 (RON2). We generated a human anti-AMA1-antibody (humAbAMA1) by EBV-transformation of sorted B-lymphocytes from a Ghanaian donor and subsequent rescue of antibody variable regions. The antibody was expressed in Nicotiana benthamiana and in HEK239-6E, characterized for binding specificity and epitope, and analyzed for its inhibitory effect on Plasmodium falciparum. The generated humAbAMA1 shows an affinity of 106-135 pM. It inhibits the parasite strain 3D7A growth in vitro with an expression system-independent IC50-value of 35 μg/ml (95% confidence interval: 33 μg/ml-37 μg/ml), which is three to eight times lower than the IC50-values of inhibitory antibodies 4G2 and 1F9. The epitope was mapped to the close proximity of the RON2-peptide binding groove. Competition for binding between the RON2-peptide and humAbAMA1 was confirmed by surface plasmon resonance spectroscopy measurements. The particularly advantageous inhibitory activity of this fully human antibody might provide a basis for future therapeutic applications.

  2. Emerging Role of the Ubiquitin Proteasome System in the Control of Shoot Apical Meristem Function

    Institute of Scientific and Technical Information of China (English)

    Elisabetta Di Giacomo; Giovanna Serino; Giovanna Frugis

    2013-01-01

    The shoot apical meristem (SAM) is a population of undifferentiated cells at the tip of the shoot axis that establishes early during plant embryogenesis and gives rise to all shoot organs throughout the plant's life.A plethora of different families of transcription factors (TFs) play a key role in establishing the equilibrium between cell differentiation and stem cell maintenance in the SAM.Fine tuning of these regulatory proteins is crucial for a proper and fast SAM response to environmental and hormonal cues,and for development progression.One effective way to rapidly inactivate TFs involves regulated proteolysis by the ubiquitin/26S proteasome system (UPS).However,a possible role of UPS-dependent protein degradation in the regulation of key SAM TFs has not been thoroughly investigated.Here,we summarize recent evidence supporting a role for the UPS in SAM maintenance and function.We integrate this survey with an in silico analysis of publicly-available microarray databases which identified ubiquitin ligases that are expressed in specific areas within the SAM,suggesting that they may regulate or act downstream of meristem-specific factors.

  3. Localization of HstI transcripts to the apical ectodermal ridge in the mouse embryo.

    Science.gov (United States)

    Suzuki, H R; Sakamoto, H; Yoshida, T; Sugimura, T; Terada, M; Solursh, M

    1992-03-01

    The HstI gene is a transforming gene, coding for a protein of the fibroblast growth factor family (Sakamoto et al., 1986). Previous RNA hybridization studies with the mouse homolog demonstrated the presence of a 3.0-kb transcript in Day 11 and 14 mouse embryos. Here we detect a 3.0-kb transcript in the limb and body of the dissected Day 11 mouse embryo. PCR amplification using HstI-specific primers also showed comparable results. In order to localize the HstI transcripts during development, corresponding HstI cDNA was isolated, and an HstI-specific region was used as a probe for in situ hybridization analysis. Serial sections of embryos from Day 8 (early-somite stages) through Days 9, 10, 11, and 12 of gestation were examined. With the antisense probe, a signal was detected in the Day 11 and 12 embryo, where it was localized to the apical ectodermal ridge (AER) of the limb bud. This structure is well known for its role in promoting the distal outgrowth of the developing limb bud. Signal was detected in both fore- and hindlimbs during the period of rapid distal growth. This restricted localization suggests a role for HstI in normal embryogenesis, including outgrowth of the limb bud.

  4. Length and activity of the root apical meristem revealed in vivo by infrared imaging.

    Science.gov (United States)

    Bizet, François; Hummel, Irène; Bogeat-Triboulot, Marie-Béatrice

    2015-03-01

    Understanding how cell division and cell elongation influence organ growth and development is a long-standing issue in plant biology. In plant roots, most of the cell divisions occur in a short and specialized region, the root apical meristem (RAM). Although RAM activity has been suggested to be of high importance to understand how roots grow and how the cell cycle is regulated, few experimental and numeric data are currently available. The characterization of the RAM is difficult and essentially based upon cell length measurements through destructive and time-consuming microscopy approaches. Here, a new non-invasive method is described that couples infrared light imaging and kinematic analyses and that allows in vivo measurements of the RAM length. This study provides a detailed description of the RAM activity, especially in terms of cell flux and cell division rate. We focused on roots of hydroponic grown poplars and confirmed our method on maize roots. How the RAM affects root growth rate is studied by taking advantage of the high inter-individual variability of poplar root growth. An osmotic stress was applied and did not significantly affect the RAM length, highlighting its homeostasis in short to middle-term responses. The methodology described here simplifies a lot experimental procedures, allows an increase in the number of individuals that can be taken into account in experiments, and means new experiments can be formulated that allow temporal monitoring of the RAM length.

  5. Correlation of apical fluid-regulating channel proteins with lung function in human COPD lungs.

    Directory of Open Access Journals (Sweden)

    Runzhen Zhao

    Full Text Available Links between epithelial ion channels and chronic obstructive pulmonary diseases (COPD are emerging through animal model and in vitro studies. However, clinical correlations between fluid-regulating channel proteins and lung function in COPD remain to be elucidated. To quantitatively measure epithelial sodium channels (ENaC, cystic fibrosis transmembrane conductance regulator (CFTR, and aquaporin 5 (AQP5 proteins in human COPD lungs and to analyze the correlation with declining lung function, quantitative western blots were used. Spearman tests were performed to identify correlations between channel proteins and lung function. The expression of α and β ENaC subunits was augmented and inversely associated with lung function. In contrast, both total and alveolar type I (ATI and II (ATII-specific CFTR proteins were reduced. The expression level of CFTR proteins was associated with FEV1 positively. Abundance of AQP5 proteins and extracellular superoxide dismutase (SOD3 was decreased and correlated with spirometry test results and gas exchange positively. Furthermore, these channel proteins were significantly associated with severity of disease. Our study demonstrates that expression of ENaC, AQP5, and CFTR proteins in human COPD lungs is quantitatively associated with lung function and severity of COPD. These apically located fluid-regulating channels may thereby serve as biomarkers and potent druggable targets of COPD.

  6. Estudio morfológico del extremo apical inactivo de diversas limas mediante microscopía electrónica de barrido

    OpenAIRE

    Canalda Sahli, Carlos; Berástegui, Esther; Arroyo Bote, Sebastiana; Rais, A.; Brau Aguadé, Esteban

    1995-01-01

    Diversas firmas han manufacturado limas con el extremo apical inactivo para permitir efectuar la instrumentación de los conductos con una acción rotatoria. El objetivo de este estudio fue evaluar el extremo apical de estas limas (diámetros 30, 40 y 50) mediante microscopía electrónica de barrido, comparándolas con otras limas clásicas. Se observó en todas ellas un extremo apical sin espiras, a diferencia de las limas K convencionales.

  7. Nerve lesions following apical extrusion of non-setting calcium hydroxide: a systematic case review and report of two cases.

    Science.gov (United States)

    Olsen, J J; Thorn, J J; Korsgaard, N; Pinholt, E M

    2014-09-01

    We present two cases of apical extrusion of non-setting, calcium hydroxide paste which had been placed as an interappointment root canal dressing during routine endodontic treatment resulting in tissue necrosis of a large part of the mandible. Surgical intervention consisted of resections in both instances. In relation to the cases presented, a systematic review of similar cases in the literature between 1980 and April 2013 was conducted which resulted in eight cases meeting the criteria outlined. As with the two presented cases, half of these eight cases showed serious adverse effects and the use of an injectable system had most often been related to apical extrusion. Consequently, great care should be taken when applying the paste into the canal system.

  8. Calcium-enriched mixture pulpotomy of a human permanent molar with irreversible pulpitis and condensing apical periodontitis

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    Saeed Asgary

    2011-01-01

    Full Text Available This case report describes a pulpotomy treatment of a permanent mature molar tooth with established irreversible pulpitis and condensing apical periodontitis, using calcium-enriched mixture (CEM cement. Clinical examination revealed that the first right lower molar had a large carious lesion with history of spontaneous/lingering pain; radiographic examination showed condensing apical periodontitis. Pulpotomy was opted as the treatment; cervical pulpotomy was carried out. Following hemostasis, the radicular pulp stumps were covered with ~2-mm-thick layer of the prepared CEM cement; the tooth was restored with amalgam. Two-year follow-up showed that the treated tooth had been symptomless, and there were no clinical signs/symptoms of either inflammation or infection. Radiographically, the periradicular lesion was completely healed with reconstruction of bone structures to normal appearance; the root canals were not calcified. According to chemical, physical, and biological properties of the CEM cement, this novel biomaterial may be suitable for endodontic treatment.

  9. Transgenic plants from shoot apical meristems of Vitis vinifera L. "Thompson Seedless" via Agrobacterium-mediated transformation.

    Science.gov (United States)

    Dutt, M; Li, Z T; Dhekney, S A; Gray, D J

    2007-12-01

    Shoot apical meristem explants of Vitis vinifera "Thompson Seedless" were used for Agrobacterium-mediated genetic transformation. It was determined that the meristems had to be subjected to a dark growth phase then wounded to obtain transgenic plants. Morphological and histological studies illustrated the role of wounding to expose apical meristem cells for transformation. A bifunctional egfp/nptII fusion gene was used to select kanamycin resistant plants that expressed green fluorescent protein (GFP). Kanamycin at a concentration of 16 mg L(-1) in selection medium resulted in recovery of non-chimeric transgenic plants that uniformly expressed GFP, whereas 8 mg L(-1) kanamycin allowed non-transgenic and/or chimeric plants to develop. Polymerase chain reaction (PCR) and Southern blot analyses confirmed the presence of transgenes and their stable integration into the genome of regenerated plants. Up to 1% of shoot tips produced stable transgenic cultures within 6 weeks of treatment, resulting in a total of 18 independent lines.

  10. Huge Left Ventricular Thrombus and Apical Ballooning associated with Recurrent Massive Strokes in a Septic Shock Patient

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    Hyun-Jung Lee

    2016-02-01

    Full Text Available The most feared complication of left ventricular thrombus (LVT is the occurrence of systemic thromboembolic events, especially in the brain. Herein, we report a patient with severe sepsis who suffered recurrent devastating embolic stroke. Transthoracic echocardiography revealed apical ballooning of the left ventricle with a huge LVT, which had not been observed in chest computed tomography before the stroke. This case emphasizes the importance of serial cardiac evaluation in patients with stroke and severe medical illness.

  11. External apical root resorption in maxillary root-filled incisors after orthodontic treatment: A split-mouth design study

    OpenAIRE

    2011-01-01

    Introduction: The purpose of this study was to compare, in a split mouth design, the external apical root resorption (EARR) associated with orthodontic treatment in root-filled maxillary incisors and their contralateral teeth with vital pulps. Methodology: The study sample consisted of 38 patients (14 males and 24 females), who had one root-filled incisor before completion of multiband/bracket orthodontic therapy for at least 1 year. For each patient, digital panoramic radiographs taken befor...

  12. Mercury toxicity in the shark (Squalus acanthias) rectal gland: apical CFTR chloride channels are inhibited by mercuric chloride.

    Science.gov (United States)

    Ratner, Martha A; Decker, Sarah E; Aller, Stephen G; Weber, Gerhard; Forrest, John N

    2006-03-01

    In the shark rectal gland, basolateral membrane proteins have been suggested as targets for mercury. To examine the membrane polarity of mercury toxicity, we performed experiments in three preparations: isolated perfused rectal glands, primary monolayer cultures of rectal gland epithelial cells, and Xenopus oocytes expressing the shark cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. In perfused rectal glands we observed: (1) a dose-dependent inhibition by mercury of forskolin/3-isobutyl-1-methylxanthine (IBMX)-stimulated chloride secretion; (2) inhibition was maximal when mercury was added before stimulation with forskolin/IBMX; (3) dithiothrietol (DTT) and glutathione (GSH) completely prevented inhibition of chloride secretion. Short-circuit current (Isc) measurements in monolayers of rectal gland epithelial cells were performed to examine the membrane polarity of this effect. Mercuric chloride inhibited Isc more potently when applied to the solution bathing the apical vs. the basolateral membrane (23 +/- 5% and 68 +/- 5% inhibition at 1 and 10 microM HgCl2 in the apical solution vs. 2 +/- 0.9% and 14 +/- 5% in the basolateral solution). This inhibition was prevented by pre-treatment with apical DTT or GSH; however, only the permeant reducing agent DTT reversed mercury inhibition when added after exposure. When the shark rectal gland CFTR channel was expressed in Xenopus oocytes and chloride conductance was measured by two-electrode voltage clamping, we found that 1 microM HgCl2 inhibited forskolin/IBMX conductance by 69.2 +/- 2.0%. We conclude that in the shark rectal gland, mercury inhibits chloride secretion by interacting with the apical membrane and that CFTR is the likely site of this action.

  13. Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis

    OpenAIRE

    Siqueira Jr., José F.; Rocas,Isabela N.; Paiva, Simone S. M.; Pinto, Tatiana Guimarães; Magalhães, Karen M.; de Lima, Kenio C.

    2007-01-01

    SIQUEIRA JR. et al. Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod., v. 104, n. 1, p. 122-130, 2007. Objective. This clinical study was undertaken to compare the effectiveness of 2.5% sodium hypochlorite (NaOCl) and 0.12% chlorhexidine digluconate as irrigants in reducing the cultivable bacterial populations in infected root canals...

  14. Effect of Calcium Hydroxide, Chlorhexidine Digluconate and Camphorated Monochlorophenol on the Sealing Ability of Biodentine Apical Plug

    Science.gov (United States)

    Srivastava, Harshit; Prasad, Ashwini B; Raisingani, Deepak; Soni, Dileep

    2016-01-01

    Introduction Teeth with immature apex are managed by establishing an apical plug using various materials and techniques. However, the use of previously placed intracanal medicament may affect the sealing ability of permanent filling material used as an apical plug. Aim To evaluate the effect of removal of previously placed Calcium Hydroxide, Chlorhexidine Digluconate and Camphorated Monochlorophenol as an intracanal medicament on the sealing ability of the Biodentine as an apical plug. Materials and Methods A total of 72 recently extracted human permanent teeth with single root were selected and stored in saline at room temperature. The crown portion of each tooth was removed at the level of cemento enamel junction; 14mm root length was taken as standard length. All the roots were submerged in 20% sulphuric acid up to 3 mm from the apex, for four days for root resorption. One sample was cut longitudinally to look for root resorption under stereo microscope. The canal preparation was done; the roots were kept in moist gauze after instrumentation. A total of 71 roots were randomly divided into three groups. GROUP 1:Calcium hydroxide paste, GROUP 2: Chlorhexidine digluconate, GROUP 3: Camphorated Monochlorophenol (CMCP). The medicaments were removed with stainless steel hand files and 0.5% sodium hypochlorite irrigation. After removal of medicament Biodentine was placed in apical third of resorbed roots and the remaining portion of the canals was filled with gutta-percha. All the 71 roots were analysed with fluid filtration method for evaluating microleakage. Results Comparing all the three groups statistically there was no significant difference. The mean values were found more for group 1 followed by group 2 & 3. Conclusion All the groups showed microleakage. Calcium hydroxide showed the maximum microleakage followed by Chlorhexidine digluconate and least with CMCP. PMID:27504409

  15. Hierarchical phosphorylation of apical membrane antigen 1 is required for efficient red blood cell invasion by malaria parasites

    OpenAIRE

    Boris Prinz; Katherine L. Harvey; Louisa Wilcke; Ulrike Ruch; Klemens Engelberg; Laura Biller; Isabelle Lucet; Steffen Erkelenz; Dorothee Heincke; Tobias Spielmann; Christian Doerig; Conrad Kunick; Brendan S Crabb; Gilson, Paul R.; Gilberger, Tim W

    2016-01-01

    Central to the pathogenesis of malaria is the proliferation of Plasmodium falciparum parasites within human erythrocytes. Parasites invade erythrocytes via a coordinated sequence of receptor-ligand interactions between the parasite and host cell. One key ligand, Apical Membrane Antigen 1 (AMA1), is a leading blood-stage vaccine and previous work indicates that phosphorylation of its cytoplasmic domain (CPD) is important to its function during invasion. Here we investigate the significance of ...

  16. Comparison of Apical Extrusion of Debris by Using Single-File, Full-Sequence Rotary and Reciprocating Systems

    Science.gov (United States)

    Ehsani, Maryam; Harandi, Azadeh; Tavanafar, Saeid; Raoof, Maryam; Galledar, Saeedeh

    2016-01-01

    Objectives: During root canal preparation, apical extrusion of debris can cause inflammation, flare-ups, and delayed healing. Therefore, instrumentation techniques that cause the least extrusion of debris are desirable. This study aimed to compare apical extrusion of debris by five single-file, full-sequence rotary and reciprocating systems. Materials and Methods: One hundred twenty human mandibular premolars with similar root lengths, apical diameters, and canal curvatures were selected and randomly assigned to six groups (n=20): Reciproc R25 (25, 0.08), WaveOne Primary (25, 0.08), OneShape (25, 0.06), F360 (25, 0.04), Neoniti A1 (25, 0.08), and ProTaper Universal. Instrumentation of the root canals was performed in accordance with the manufacturers’ instructions. Each tooth's debris was collected in a pre-weighed vial. After drying the debris in an incubator, the mass was measured three times consecutively; the mean was then calculated. The preparation time by each system was also measured. For data analysis, one-way ANOVA and Games-Howell post hoc test were used. Results: The mean masses (±standard deviation) of the apical debris were as follows: 2.071±1.38mg (ProTaper Universal), 1.702±1.306mg (Neoniti A1), 1.295±0.839mg (OneShape), 1.109±0.676mg (WaveOne), 0.976±0.478mg (Reciproc) and 0.797±0.531mg (F360). Compared to ProTaper Universal, F360 generated significantly less debris (P=0.02). The ProTaper system required the longest preparation time (mean=88.6 seconds); the Reciproc (P=0.008), OneShape (P=0.006), and F360 (P=0.001) required significantly less time (PProTaper Universal.

  17. The Effects of Alkaline pH on Microleakage of Mineral Trioxide Aggregate and Calcium-Enriched Mixture Apical Plugs

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    Hossein Mirhadi

    2016-03-01

    Full Text Available Statement of the Problem: Alkaline pH can affect the physical and chemical properties and sealing ability of apical plug material. Calcium hydroxide is used in non-vital teeth as an intracanal medication to complete disinfection of root canals. It raises the pH of environment to alkaline value. Purpose: The aim of this in vitro study was to evaluate and compare the effect of alkaline pH on the sealing ability of calcium-enriched mixture (CEM cement and mineral trioxide aggregate (MTA apical plugs. Materials and Method: Seventy single-rooted human maxillary anterior teeth were randomly divided to two experimental groups for Angelus MTA and CEM cement (n=30 and two control groups (n=5. Each group was divided into two subgroups of 15 for neutral and alkaline pH, and 1 negative and 1 positive control groups of 5. The root canals were cleaned and shaped by using ProTaper rotary system (Dentsply Maillefer; Ballaigues, Switzerland and the terminal 3mm of the roots were resected. Then, MTA and CEM cement were condensed in apical region with 3mm thickness. The samples were exposed to two environments with different pH values of 13 and 7.4. The leakage was assessed by using the fluid filtration technique at 1, 7, 14, 30 days intervals. Data were analyzed by the repeated measures MANOVA. Results: There was no statistically significant difference in the rate of microleakage between neutral and alkaline pH of CEM cement and MTA (p> 0.05. The sealing ability of MTA in an alkaline pH of 13 was significantly less than CEM cement in this pH (p< 0.05. Conclusion: An environment with alkaline pH had no adverse effect on the sealing ability of MTA and CEM cement used as apical plugs. CEM cement had better sealing ability in alkaline pH.

  18. Apical root canal transportation of different pathfinding systems and their effects on shaping ability of ProTaper Next

    OpenAIRE

    Turker, Sevinc Aktemur; Uzunoglu, Emel

    2015-01-01

    Background This study aimed to compare glide path preparation of different pathfinding systems and their effects on the apical transportation of ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland) in mesial root canals of extracted human mandibular molars, using digital subtraction radiography. Material and Methods The mesial canals of 40 mandibular first molars (with curvature angles between 25° and 35°) were selected for this study. The specimens were divided randomly into 4 groups ...

  19. Apical transportation of manual NiTi instruments and a hybrid technique in severely curved simulated canals

    OpenAIRE

    Aurenaila Nascimento Gonçalves; Matheus Franco da Frota; Emilio Carlos Sponchiado Júnior; Fredson Marcio Acris de Carvalho; Lucas da Fonseca Roberti Garcia; André Augusto Franco Marques

    2015-01-01

    Aim: To evaluate the apical transportation induced by two instrumentation techniques in severely curved simulated canals. Materials and Methods: Forty simulated canals were divided into two groups (n = 20), according to the following instrumentation techniques: ProTaper Universal Manual System and a hybrid technique. The simulated canals in the ProTaper group were prepared following the technique recommended by the manufacturer: SX files in the cervical third of the root canal and S1, S2,...

  20. Mechanically, the shoot apical meristem of Arabidopsis behaves like a shell inflated by a pressure of about 1 MPa

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    Léna eBeauzamy

    2015-11-01

    Full Text Available In plants, the shoot apical meristem contains the stem cells and is responsible for the generation of all aerial organs. Mechanistically, organogenesis is associated with an auxin-dependent local softening of the epidermis. This has been proposed to be sufficient to trigger outgrowth, because the epidermis is thought to be under tension and stiffer than internal tissues in all the aerial part of the plant. However, this has not been directly demonstrated in the shoot apical meristem. Here we tested this hypothesis in Arabidopsis using indentation methods and modeling. We considered two possible scenarios: either the epidermis does not have unique properties and the meristem behaves as a homogeneous linearly-elastic tissue, or the epidermis is under tension and the meristem exhibits the response of a shell under pressure. Large indentation depths measurements with a large tip (~size of the meristem were consistent with a shell-like behavior. This also allowed us to deduce a value of turgor pressure, estimated at 0.82 ± 0.16 MPa. Indentation with atomic force microscopy provided local measurements of pressure in the epidermis, further confirming the values obtained from large deformations. Altogether, our data demonstrate that the Arabidopsis shoot apical meristem behaves like a shell under a MPa range pressure and support a key role for the epidermis in shaping the shoot apex.

  1. Alpha-enolase on apical surface of renal tubular epithelial cells serves as a calcium oxalate crystal receptor

    Science.gov (United States)

    Fong-Ngern, Kedsarin; Thongboonkerd, Visith

    2016-10-01

    To search for a strategy to prevent kidney stone formation/recurrence, this study addressed the role of α-enolase on apical membrane of renal tubular cells in mediating calcium oxalate monohydrate (COM) crystal adhesion. Its presence on apical membrane and in COM crystal-bound fraction was confirmed by Western blotting and immunofluorescence staining. Pretreating MDCK cells with anti-α-enolase antibody, not isotype-controlled IgG, dramatically reduced cell-crystal adhesion. Immunofluorescence staining also confirmed the direct binding of purified α-enolase to COM crystals at {121} > {100} > {010} crystal faces. Coating COM crystals with urinary proteins diminished the crystal binding capacity to cells and purified α-enolase. Moreover, α-enolase selectively bound to COM, not other crystals. Chemico-protein interactions analysis revealed that α-enolase interacted directly with Ca2+ and Mg2+. Incubating the cells with Mg2+ prior to cell-crystal adhesion assay significantly reduced crystal binding on the cell surface, whereas preincubation with EDTA, a divalent cation chelator, completely abolished Mg2+ effect, indicating that COM and Mg2+ competitively bind to α-enolase. Taken together, we successfully confirmed the role of α-enolase as a COM crystal receptor to mediate COM crystal adhesion at apical membrane of renal tubular cells. It may also serve as a target for stone prevention by blocking cell-crystal adhesion and stone nidus formation.

  2. Qualitative SEM/EDS analysis of microleakage and apical gap formation of adhesive root-filling materials

    Directory of Open Access Journals (Sweden)

    Soraia de Fátima Carvalho Souza

    2012-06-01

    Full Text Available OBJECTIVE: The aim of this study was to compare the correspondence between gap formation and apical microleakage in root canals filled with epoxy resin-based (AH Plus combined or not with resinous primer or with a dimethacrylate-based root canal sealer (Epiphany. MATERIAL AND METHODS: Thirty-nine lower single-rooted human premolars were filled by the lateral condensation technique (LC and immersed in a 50-wt% aqueous silver nitrate solution at 37ºC (24 h. After longitudinal sectioning, epoxy resin replicas were made from the tooth specimens. Both the replicas and the specimens were prepared for scanning electron microscopy (SEM. The gaps were observed in the replicas. Apical microleakage was detected in the specimens by SEM/energy dispersive spectroscopy (SEM/EDS. The data were analyzed statistically using an Ordinal Logistic Regression model and Analysis of Correspondence (α=0.05. RESULTS: Epiphany presented more regions containing gaps between dentin and sealer (p0.05. CONCLUSIONS: The resinous primer did not improve the sealing ability of AH Plus sealer and the presence of gaps had an effect on apical microleakage for all materials.

  3. Transforming Growth Factor -ß1 (TGF-ß1 immunoreactivity in heterotopic grafts of adult dental apical papilla.

    Directory of Open Access Journals (Sweden)

    Telmo Mezadri

    2015-02-01

    Full Text Available To analyze the expression of transforming growth factor-ß1 in heterotopic grafts of adult dental apical papilla. Methodology: The apical papilla of adult Wistar rats was grafted in the ear of the same donor rats 1, 3, 7 and 14 days after grafting, rats were perfused and the tissue containing the graft was processed for histological conventional technique and for immunohistochemical detection of transforming growth factor-ß1. Results: Heterotopically grafted apical papilla developed osteoid dentine. In an early post-grafting stage, odontoblast-like cells organized themselves in palisade and synthesized dentine. However, newly formed dentine possessed the structural appearance of reactive osteoid dentine, which was systematically destroyed by the activity of osteoclaste-like cells. Transforming Growth Factor-ß1 was observed in mesenchymal cells, extracellular matrix of the graft and surrounding host tissue, while odontoblast-like cells were systematically devoid of immunoreactivity. Conclusion: The different expression of transforming growth factor-ß1 between normal tissue and grafted tissue development suggests that in heterotopic graft conditions the inflammatory mediation of the transforming growth factor-ß1 prevails against its morphogenetic role

  4. In vivo PTH provokes apical NHE3 and NaPi2 redistribution and Na-K-ATPase inhibition

    DEFF Research Database (Denmark)

    Zhang, Y; Norian, J M; Magyar, C E

    1999-01-01

    The aim of this study was to test the hypothesis that in vivo administration of parathyroid hormone (PTH) provokes diuresis/natriuresis through redistribution of proximal tubule apical sodium cotransporters (NHE3 and NaPi2) to internal stores and inhibition of basolateral Na-K-ATPase activity....... With this diuresis/natriuresis, 25% of NHE3 and 18% of NaPi2 immunoreactivity redistributed from apical membranes to higher density fractions containing intracellular membrane markers, and basolateral Na-K-ATPase activity decreased 25%. [Nle8,18,Tyr34]PTH-(3-34) failed to increase V or CLi or to provoke...... redistribution of NHE3 or NaPi2, but it did inhibit Na-K-ATPase activity 25%. We conclude that in vivo PTH stimulates natriuresis/diuresis associated with internalization of apical NHE3 and NaPi2 and inhibition of Na-K-ATPase activity, that cAMP-protein kinase A stimulation is necessary for the natriuresis/diuresis...

  5. Microbiological evaluation of different irrigation protocols on root canal disinfection in teeth with apical periodontitis: an in vivo study.

    Science.gov (United States)

    Cohenca, Nestor; Silva, Lea Assed Bezerra; Silva, Raquel Assed Bezerra; Nelson-Filho, Paulo; Heilborn, Carlos; Watanabe, Evandro; Saraiva, Maria Conceição Pereira

    2013-01-01

    The present in vivo study was designed to evaluate the efficacy of apical negative pressure irrigation (ANP), passive ultrasonic irrigation (PUI) and positive pressure irrigation (PP) in the reduction of intracanal bacteria of dogs' teeth with pulp necrosis and apical periodontitis. Eighty root canals were randomly distributed into 3 experimental and 2 control groups according to the irrigation delivery system: group ANP (n=20), group PUI (n=20), group PP (n=20), group PC (positive control - sterile saline irrigation; n=10) and group NC (negative control - vital pulps not subjected to bacterial inoculation; n=10). The first sample (S1) was collected at baseline, and the second sample (S2) was collected after the disinfection protocols. All samples were seeded in culture media for anaerobic bacteria. CFU counts were analyzed statistically by the Kruskal-Wallis, Dwass-Steel-Critchlow-Fligner post-hoc and Chi-square followed by Tukey like multiple comparisons for proportions (α=0.05). All experimental groups were effective in reducing Gram-positive bacteria compared with PC (p0.05). In dog's teeth with apical periodontitis, the use of ANP and PUI can be considered promising disinfection protocols as both delivery systems promoted a significant bacterial reduction.

  6. Novel regulation of cell [Na(+)] in macula densa cells: apical Na(+) recycling by H-K-ATPase.

    Science.gov (United States)

    Peti-Peterdi, János; Bebok, Zsuzsa; Lapointe, Jean-Yves; Bell, P Darwin

    2002-02-01

    Na-K-ATPase is the nearly ubiquitous enzyme that maintains low-Na(+), high-K(+) concentrations in cells by actively extruding Na(+) in exchange for K(+). The prevailing paradigm in polarized absorbing epithelial cells, including renal nephron segments and intestine, has been that Na-K-ATPase is restricted to the basolateral membrane domain, where it plays a prominent role in Na(+) absorption. We have found, however, that macula densa (MD) cells lack functionally and immunologically detectable amounts of Na-K-ATPase protein. In fact, these cells appear to regulate their cytosolic [Na(+)] via another member of the P-type ATPase family, the colonic form of H-K-ATPase, which is located at the apical membrane in these cells. We now report that this constitutively expressed apical MD colonic H-K-ATPase can function as a Na(H)-K-ATPase and regulate cytosolic [Na(+)] in a novel manner. This apical Na(+)-recycling mechanism may be important as part of the sensor function of MD cells and represents a new paradigm in cell [Na(+)] regulation.

  7. Partial Pulpotomy of Immature Teeth with Apical Periodontitis using Bioceramics and Mineral Trioxide Aggregate: A Report of Three Cases.

    Science.gov (United States)

    Jiang, Shan; Wu, Hao; Zhang, Cheng Fei

    2016-06-01

    Pulpal necrosis of an immature permanent tooth with an open apex poses a challenge for the clinician. The conventional apexification technique using calcium hydroxide has yielded short-term success, but this technique has inevitable shortcomings. Hence, this case series aimed to evaluate the effectiveness of using bioceramics (iRoot BP) or mineral trioxide aggregate (MTA) for partial pulpotomies. Three boys aged 9 to 11 years old presented with partial pulp necrosis and symptomatic apical periodontitis of the mandibular right and left second premolar. The involved teeth were treated with a partial pulpotomy using either iRoot BP (case 1 and 2) or MTA (case 3). At the 8-month follow-up, no abnormal clinical signs or symptoms were observed. Periapical radiographs revealed a significant reduction in periapical radiolucency, a marked increase in the root canal wall thickness and ongoing closure of the apical opening. The bioceramic material (iRoot BP) and MTA both produced successful outcomes in the partial pulpotomy of immature teeth with partial pulp necrosis and apical periodontitis. However, iRoot BP was superior in terms of ease of clinical application, and would therefore be a better treatment alternative than MTA.

  8. Comparative evaluation of sealing properties of different obturation systems placed over apically fractured rotary NiTi files

    Directory of Open Access Journals (Sweden)

    Sonali Taneja

    2012-01-01

    Full Text Available Aim: To evaluate sealing properties of different obturation systems placed over apically fractured rotary NiTi files. Materials and Methods: Forty freshly extracted human mandibular premolars were prepared by using Protaper (Dentsply-Maillefer, Ballaigues, Switzerland or the RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland systems (n=20 for each, after which half of the specimens were subjected to instrument separation at the apical level. Roots with and without apically separated instruments (n=5 were filled with the two obturation systems i.e. Thermafil and lateral compaction technique. The modified glucose penetration setup was used to assess the microleakage. The leakage data was statistically analyzed. Results: The amount of leakage was significantly lower in specimens containing fractured instruments, regardless of the obturation method used. Roots obturated with Thermafil displayed significantly less leakage than cold lateral compaction technique, both, in the presence and absence of separated instruments. There was no significant difference among specimens prepared with ProTaper and RaCe when Thermafil obturation was done. But with cold lateral compaction technique, RaCe system showed less leakage as compared to ProTaper system. Conclusion: The type of obturation may play more important role than the type of instrument or retained/non-retained instrument factor.

  9. A Comparison of Profile, Race and FKG Systems in Eliminating Enterococcus Faecalis from the Apical Third of Mandibular Premolars

    Directory of Open Access Journals (Sweden)

    K. Nazari Moghaddam

    2006-12-01

    Full Text Available Statement of problem: Microorganisms are essential for the development of periradicular diseases and are one of the major causative factors associated with endodontic treatment failures. Different instruments and preparation techniques have been developed in Endodontics to eliminate or reduce intracanal bacteria.Purpose: The aim of this study was to compare the amount of remaining E. faecalis in the apical third of root canals following instrumentation with Profile, Race and FKG files.Materials and Methods: Ninety freshly extracted mandibular single canal premolars were selected. A horizontal groove was made circumferentially around the roots at a depth of 0.5mm and a distance of 5 mm from the anatomic apex. All the equipments were sterilized overnight by ethylene oxide gas. Root canals, inoculated with E. faecalis suspension, were prepared using Profile, Race or FKG instruments in a step-back technique. Master apical file, amount of irrigant for each canal and working length were similar in all specimens groups. Following preparation, the apical portions of the roots were separated from the previously made grooves and were sampled by sterile paper points. Statistical analysis was performed using ANOVA and Duncan’s multiple range tests.Results: Profile was significantly more effective in eliminating E. faecalis as compared to Race. A significant difference was not observed between FKG and the other two studied instrumentation techniques.Conclusions: Neither of the methods could completely eliminate E. faecalis from the root canals.

  10. Transforming Growth Factor-ß1 (TGF-ß1 immunoreactivity in heterotopic grafts of adult dental apical papilla.

    Directory of Open Access Journals (Sweden)

    Telmo José Mezadri

    2015-02-01

    Full Text Available ABSTRACT Objective: To analyze the expression of transforming growth factor-ß1 in heterotopic grafts of adult dental apical papillae. Methodology: Adult apical papillae of Wistar rats were grafted in the ear of the same donor rats. 1, 3, 7 and 14 days after grafting, rats were perfused and the tissue containing the graft was processed for histological conventional technique and for immunohistochemical detection of transforming growth factor-ß1. Results: Heterotopically grafted apical papilla developed osteoid dentine. In an early post-grafting stage, odontoblast-like cells organized themselves in palisade and synthesized dentine. However, newly formed dentine possessed the structural appearance of reactive osteoid dentine, which was systematically destroyed by the activity of osteoclaste-like cells. Transforming Growth Factor-ß1 was observed in mesenchymal cells, extracellular matrix of the graft and surrounding host tissue, while odontoblast-like cells were systematically devoid of immunoreactivity. Conclusion: The different expression of transforming growth factor-ß1 between normal tissue and grafted tissue development suggests that in heterotopic graft conditions the inflammatory mediation of the transforming growth factor-ß1 prevails against its morphogenetic role.

  11. Drying protocol influence on the bond strength and apical sealing of three different endodontic sealers.

    Science.gov (United States)

    Paula, Adrianne Calixto Freire de; Brito-Júnior, Manoel; Araújo, Carla Cristina Camilo; Sousa-Neto, Manoel Damião; Cruz-Filho, Antonio Miranda da

    2016-05-20

    The aim of this study was to evaluate the influence of drying protocols (DP) on the apical sealing (AS) and on the bond strength (BS) of teeth filled with different sealers. The root canals of one hundred and fifty-six roots of maxillary canines were prepared with Reciproc rotary files (R50). The teeth were randomly divided into four groups (n = 39), according to the DP: GI-paper points; GII-70% isopropyl alcohol + aspiration with NaviTip points; GIII-95% ethanol + paper points; GIV-EndoVac + paper points. Each group was divided into subgroups, according to the sealer used: AH Plus, Sealapex and MTA Fillapex, using a single-cone technique. Evaluation of AS and BS was performed with fluid filtration (FF) and push-out (PO) methods, respectively. The PO test consisted of sectioning the roots, and subjecting a single slice from each third to testing and analysis for failure type. The data was submitted to two-way and three-way variance analysis (ANOVA) and Tukey (α = 5%). The AS showed no drying protocol influence. The FF results revealed a statistically significant difference between MTA and Sealapex (p 0.05), but that there was such a difference among the sealers (p < 0.05), among the protocols (p < 0.05), and in the interaction between sealers and protocols (p < 0.05). AH Plus revealed the highest BS values among the sealers; the highest BS results for the sealers occurred with the specimens used with isopropyl alcohol, compared with ethanol and EndoVac.

  12. Cell size and growth regulation in the Arabidopsis thaliana apical stem cell niche

    Science.gov (United States)

    Willis, Lisa; Refahi, Yassin; Wightman, Raymond; Landrein, Benoit; Teles, José; Huang, Kerwyn Casey; Meyerowitz, Elliot M.

    2016-01-01

    Cell size and growth kinetics are fundamental cellular properties with important physiological implications. Classical studies on yeast, and recently on bacteria, have identified rules for cell size regulation in single cells, but in the more complex environment of multicellular tissues, data have been lacking. In this study, to characterize cell size and growth regulation in a multicellular context, we developed a 4D imaging pipeline and applied it to track and quantify epidermal cells over 3–4 d in Arabidopsis thaliana shoot apical meristems. We found that a cell size checkpoint is not the trigger for G2/M or cytokinesis, refuting the unexamined assumption that meristematic cells trigger cell cycle phases upon reaching a critical size. Our data also rule out models in which cells undergo G2/M at a fixed time after birth, or by adding a critical size increment between G2/M transitions. Rather, cell size regulation was intermediate between the critical size and critical increment paradigms, meaning that cell size fluctuations decay by ∼75% in one generation compared with 100% (critical size) and 50% (critical increment). Notably, this behavior was independent of local cell–cell contact topologies and of position within the tissue. Cells grew exponentially throughout the first >80% of the cell cycle, but following an asymmetrical division, the small daughter grew at a faster exponential rate than the large daughter, an observation that potentially challenges present models of growth regulation. These growth and division behaviors place strong constraints on quantitative mechanistic descriptions of the cell cycle and growth control. PMID:27930326

  13. Concordance of transcriptional and apical benchmark dose levels for conazole-induced liver effects in mice.

    Science.gov (United States)

    Bhat, Virunya S; Hester, Susan D; Nesnow, Stephen; Eastmond, David A

    2013-11-01

    The ability to anchor chemical class-based gene expression changes to phenotypic lesions and to describe these changes as a function of dose and time informs mode-of-action determinations and improves quantitative risk assessments. Previous global expression profiling identified a 330-probe cluster differentially expressed and commonly responsive to 3 hepatotumorigenic conazoles (cyproconazole, epoxiconazole, and propiconazole) at 30 days. Extended to 2 more conazoles (triadimefon and myclobutanil), the present assessment encompasses 4 tumorigenic and 1 nontumorigenic conazole. Transcriptional benchmark dose levels (BMDL(T)) were estimated for a subset of the cluster with dose-responsive behavior and a ≥ 5-fold increase or decrease in signal intensity at the highest dose. These genes primarily encompassed CAR/RXR activation, P450 metabolism, liver hypertrophy- glutathione depletion, LPS/IL-1-mediated inhibition of RXR, and NRF2-mediated oxidative stress pathways. Median BMDL(T) estimates from the subset were concordant (within a factor of 2.4) with apical benchmark doses (BMDL(A)) for increased liver weight at 30 days for the 5 conazoles. The 30-day median BMDL(T) estimates were within one-half order of magnitude of the chronic BMDLA for hepatocellular tumors. Potency differences seen in the dose-responsive transcription of certain phase II metabolism, bile acid detoxification, and lipid oxidation genes mirrored each conazole's tumorigenic potency. The 30-day BMDL(T) corresponded to tumorigenic potency on a milligram per kilogram day basis with cyproconazole > epoxiconazole > propiconazole > triadimefon > myclobutanil (nontumorigenic). These results support the utility of measuring short-term gene expression changes to inform quantitative risk assessments from long-term exposures.

  14. Alanine mutagenesis of the primary antigenic escape residue cluster, c1, of apical membrane antigen 1.

    Science.gov (United States)

    Dutta, Sheetij; Dlugosz, Lisa S; Clayton, Joshua W; Pool, Christopher D; Haynes, J David; Gasser, Robert A; Batchelor, Adrian H

    2010-02-01

    Antibodies against apical membrane antigen 1 (AMA1) inhibit invasion of Plasmodium merozoites into red cells, and a large number of single nucleotide polymorphisms on AMA1 allow the parasite to escape inhibitory antibodies. The availability of a crystal structure makes it possible to test protein engineering strategies to develop a monovalent broadly reactive vaccine. Previously, we showed that a linear stretch of polymorphic residues (amino acids 187 to 207), localized within the C1 cluster on domain 1, conferred the highest level of escape from inhibitory antibodies, and these were termed antigenic escape residues (AER). Here we test the hypothesis that immunodampening the C1 AER will divert the immune system toward more conserved regions. We substituted seven C1 AER of the FVO strain Plasmodium falciparum AMA1 with alanine residues (ALA). The resulting ALA protein was less immunogenic than the native protein in rabbits. Anti-ALA antibodies contained a higher proportion of cross-reactive domain 2 and domain 3 antibodies and had higher avidity than anti-FVO. No overall enhancement of cross-reactive inhibitory activity was observed when anti-FVO and anti-ALA sera were compared for their ability to inhibit invasion. Alanine mutations at the C1 AER had shifted the immune response toward cross-strain-reactive epitopes that were noninhibitory, refuting the hypothesis but confirming the importance of the C1 cluster as an inhibitory epitope. We further demonstrate that naturally occurring polymorphisms that fall within the C1 cluster can predict escape from cross-strain invasion inhibition, reinforcing the importance of the C1 cluster genotype for antigenic categorization and allelic shift analyses in future phase 2b trials.

  15. A radiographic analysis of external apical root resorption of maxillary incisors during active orthodontic treatment.

    Science.gov (United States)

    Mohandesan, Hooman; Ravanmehr, Hossein; Valaei, Nasser

    2007-04-01

    External apical root resorption (EARR) is an undesirable consequence of orthodontic treatment. The purpose of this study was to measure the amount of EARR and to examine its clinical significance in maxillary incisors, during a 12-month active treatment period. A further aim was to examine the contribution of gender, treatment technique, treatment duration, and extraction of maxillary first premolars to EARR. The sample comprised 151 maxillary incisor teeth in 40 patients (16 males, 24 females) aged 12-22 years, with different malocclusions. Standard periapical radiographs, using the long-cone paralleling technique, were obtained before and 6 and 12 months after the start of treatment. Quantitative measurements for 80 central and 71 lateral maxillary incisors were performed separately and corrected for image distortion. Root length reduction was calculated in millimetres and in terms of the percentage of the original root length. Resorption of more than 1 mm at 12 months of active treatment was considered to be clinically significant. On average, the degree of EARR for the maxillary central incisors was 0.77 +/- 0.42 and 1.67 +/- 0.64 mm, respectively, during the 6- and 12-month follow-up (P incisors, the degree of EARR was 0.88 +/- 0.51 and 1.79 +/- 0.66 mm, respectively (P resorption was found for 74 per cent of the centrals and 82 per cent of the laterals. No significant correlation was observed between EARR and treatment technique. EARR was found to be correlated with gender for the lateral incisors. The effect of treatment duration (P < 0.001) and premolar extraction (P < 0.001) was statistically significant for both tooth groups.

  16. Cytotoxicity of Various Endodontic Materials on Stem Cells of Human Apical Papilla

    Science.gov (United States)

    Saberi, Eshagh Ali; Karkehabadi, Hamed; Mollashahi, Narges Farhad

    2016-01-01

    Introduction: This in vitro study assessed and compared the cytotoxicity of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement, Biodentine (BD) and octacalcium phosphate (OCP) on stem cells of the human apical papilla (SCAP). Methods and Materials: SCAPs were isolated from two semi-impacted third molars. The cells were cultured in wells of an insert 24-well plate and were then incubated. The plates were then removed from the incubator and randomly divided into four experimental groups that were exposed to 1-mm discs of set MTA, CEM, BD or OCP, and one untreated control group. After 24, 48 and 168 h, the plates were removed from the incubator and 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) solution was added to each well. Data were analyzed at different time points using the repeated measures ANOVA followed by Bonferroni test and the level of significance was set at 0.05. Results: Cytotoxicity of the four materials was not significantly different from that of the control group at 24, 48 and 168 h (P>0.05). Two-by-two comparison revealed that cytotoxicity of MTA and CEM cement was significantly different from each other at 168 h (P<0.05) although the cytotoxicity of CEM was less than MTA. Cytotoxicity of OCP and MTA was also significantly different from each other at 48 h and OCP had more favorable biocompatibility than MTA (P<0.05). Conclusion: CEM, OCP, BD and MTA showed acceptable biocompatibility when exposed to SCAP. Over time, CEM showed the least cytotoxicity among the materials under study. PMID:26843872

  17. Evaluation of dental expertise with intra-oral peri-apical view radiographs for forensic identification

    Directory of Open Access Journals (Sweden)

    Kanwalpreet Kaur Bhullar

    2014-01-01

    Full Text Available Background: Identification of a dead person is important in starting the investigation into the circumstances of death. In the absence of forensic odontologist, it is vital that general dentists are able to compare the ante mortem-post mortem (AM-PM records and with their ability, correctly interpret the individuality of the person. Aims: This study wascarried out to find out the accuracy with which undergraduate, graduate and post-graduate dentists can do this comparison, using the simulated AM-PM intra-oral peri-apical (IOPA view radiographs. Setting and Design: A total of 60 investigators of which 20 undergraduate students, 20 general dentists, 20 post-graduate dentists viewed 10 pairs of simulated AM and PM radiographs and recorded their findings. Materials and Methods: Ten pairs of simulated AM-PM IOPA view radiographs were given to 60 dentists to investigate their discriminatory potential for dental identification purposes. The results were statistically analyzed. Statistical Analysis: χ2 -test and Mann-Whitney U-test were carried out to compare the sensitivity, specificity and accuracy of the three types of examiners (UG, G, PG. Results: The results showed sensitivity of 59.8%, specificity of 62.6%, accuracy of 61% for undergraduate students, sensitivity of 86.6%, specificity of 87.5%, accuracy of 87% for graduate doctors, sensitivity of 89.3%, specificity of 92.3% and accuracy of 90.5% for post-graduate doctors respectively. Conclusion: Inexperienced investigators in forensic identification showed fairly acceptable results, therefore, introduction of forensic odontology in an undergraduate course may help general dentists to provide better service, if required, in the absence of a forensic odontologist.

  18. Apical pattern of fruit production in the racemes of Ceratonia siliqua (Leguminosae: Caesalpinioideae): role of pollinators.

    Science.gov (United States)

    Arista, M; Ortiz, P L; Talavera, S

    1999-12-01

    Fruit production and arrangement within the raceme were studied in two dioecious populations of Ceratonia siliqua (Leguminosae: Caesalpinioideae), an arboreal species that produces caulogenous racemes (emerging only from the old branches) with numerous flowers. Fruit production per raceme was low and similar between years and populations and even between individuals. During flowering, there were considerable flower losses from predation and lack of pollination. A mean of nine flowers per raceme began the transformation into fruits, of which 77% aborted. The final fruit production per raceme increased significantly following hand pollination, but was always very much lower than the availability of flowers in the raceme. The results suggest that fruit production of each raceme is limited by both availability of resources and a deficient pollination. In racemes setting fruit arrangement follows a definite pattern that remains constant between years and populations: fruit production was significantly higher in the apical zone of the raceme and lower in the basal zone. The pollinators of C. siliqua (flies and wasps) showed a clear preference for beginning their visits at the apex of a raceme. As a result, the pollen load deposited on the stigmas decreased from apex to base of the raceme. In most of the flowers situated in the central and basal zone of the raceme, the number of pollen grains deposited on their stigmas was lower than the number of their ovules. The high number of seeds in developed fruits suggests that the plant selectively aborts flowers that receive a smaller pollen load. The results indicate that the final pattern of fruit arrangement within the raceme is a direct result of pollinator activity.

  19. Differential regulation of the Hippo pathway by adherens junctions and apical-basal cell polarity modules.

    Science.gov (United States)

    Yang, Chih-Chao; Graves, Hillary K; Moya, Ivan M; Tao, Chunyao; Hamaratoglu, Fisun; Gladden, Andrew B; Halder, Georg

    2015-02-10

    Adherens junctions (AJs) and cell polarity complexes are key players in the establishment and maintenance of apical-basal cell polarity. Loss of AJs or basolateral polarity components promotes tumor formation and metastasis. Recent studies in vertebrate models show that loss of AJs or loss of the basolateral component Scribble (Scrib) cause deregulation of the Hippo tumor suppressor pathway and hyperactivation of its downstream effectors Yes-associated protein (YAP) and Transcriptional coactivator with PDZ-binding motif (TAZ). However, whether AJs and Scrib act through the same or independent mechanisms to regulate Hippo pathway activity is not known. Here, we dissect how disruption of AJs or loss of basolateral components affect the activity of the Drosophila YAP homolog Yorkie (Yki) during imaginal disc development. Surprisingly, disruption of AJs and loss of basolateral proteins produced very different effects on Yki activity. Yki activity was cell-autonomously decreased but non-cell-autonomously elevated in tissues where the AJ components E-cadherin (E-cad) or α-catenin (α-cat) were knocked down. In contrast, scrib knockdown caused a predominantly cell-autonomous activation of Yki. Moreover, disruption of AJs or basolateral proteins had different effects on cell polarity and tissue size. Simultaneous knockdown of α-cat and scrib induced both cell-autonomous and non-cell-autonomous Yki activity. In mammalian cells, knockdown of E-cad or α-cat caused nuclear accumulation and activation of YAP without overt effects on Scrib localization and vice versa. Therefore, our results indicate the existence of multiple, genetically separable inputs from AJs and cell polarity complexes into Yki/YAP regulation.

  20. Peptidases compartmentalized to the Ascaris suum intestinal lumen and apical intestinal membrane.

    Directory of Open Access Journals (Sweden)

    Douglas P Jasmer

    2015-01-01

    Full Text Available The nematode intestine is a tissue of interest for developing new methods of therapy and control of parasitic nematodes. However, biological details of intestinal cell functions remain obscure, as do the proteins and molecular functions located on the apical intestinal membrane (AIM, and within the intestinal lumen (IL of nematodes. Accordingly, methods were developed to gain a comprehensive identification of peptidases that function in the intestinal tract of adult female Ascaris suum. Peptidase activity was detected in multiple fractions of the A. suum intestine under pH conditions ranging from 5.0 to 8.0. Peptidase class inhibitors were used to characterize these activities. The fractions included whole lysates, membrane enriched fractions, and physiological- and 4 molar urea-perfusates of the intestinal lumen. Concanavalin A (ConA was confirmed to bind to the AIM, and intestinal proteins affinity isolated on ConA-beads were compared to proteins from membrane and perfusate fractions by mass spectrometry. Twenty-nine predicted peptidases were identified including aspartic, cysteine, and serine peptidases, and an unexpectedly high number (16 of metallopeptidases. Many of these proteins co-localized to multiple fractions, providing independent support for localization to specific intestinal compartments, including the IL and AIM. This unique perfusion model produced the most comprehensive view of likely digestive peptidases that function in these intestinal compartments of A. suum, or any nematode. This model offers a means to directly determine functions of these proteins in the A. suum intestine and, more generally, deduce the wide array functions that exist in these cellular compartments of the nematode intestine.

  1. Learning Networks, Networked Learning

    NARCIS (Netherlands)

    Sloep, Peter

    2011-01-01

    Sloep, P. B. (2011). Learning Networks, Networked Learning. Presentation at Annual Assembly of the European Society for the Systemic Innovation of Education - ESSIE. May, 27, 2011, Leuven, Belgium: Open University in the Netherlands.

  2. Learning Networks, Networked Learning

    NARCIS (Netherlands)

    Sloep, Peter; Berlanga, Adriana

    2010-01-01

    Sloep, P. B., & Berlanga, A. J. (2011). Learning Networks, Networked Learning [Redes de Aprendizaje, Aprendizaje en Red]. Comunicar, XIX(37), 55-63. Retrieved from http://dx.doi.org/10.3916/C37-2011-02-05

  3. Plasma membrane calcium pump (PMCA) isoform 4 is targeted to the apical membrane by the w-splice insert from PMCA2

    OpenAIRE

    Antalffy, Géza; Mauer, Amy S.; Pászty, Katalin; Hegedus, Luca; Padányi, Rita; Enyedi, Ágnes; STREHLER, EMANUEL E.

    2012-01-01

    Local Ca2+ signaling requires proper targeting of the Ca2+ signaling toolkit to specific cellular locales. Different isoforms of the plasma membrane Ca2+ pump (PMCA) are responsible for Ca2+ extrusion at the apical and basolateral membrane of polarized epithelial cells, but the mechanisms and signals for differential targeting of the PMCAs are not well understood. Recent work demonstrated that the alternatively spliced w-insert in PMCA2 directs this pump to the apical membrane. We now show th...

  4. Non-apical positive surgical margins after radical prostatectomy for pT2 prostate cancer is associated with the highest risk of recurrence

    DEFF Research Database (Denmark)

    Roder, Martin Andreas; Kawa, Sandra; Scheike, Thomas

    2014-01-01

    BACKGROUND AND OBJECTIVE: To investigate how location of positive surgical margins (PSM) in pT2 tumors affect the risk of biochemical recurrence (BR). METHODS: The study includes 1,133 consecutive patients from 1995 until end of 2011, who had organ-confined disease (pT2) following RP. The location...... of PSM was stratified into apical and non-apical. BR was defined as the first PSA ≥ 0.2 ng/ml after RP. Risk of BR was analyzed with Kaplan-Meier and Cox regression analysis. RESULTS: Median follow-up was 3.6 years (range: 0.5-15.5 years). The overall pT2 PSM rate was 26.3%. Overall, a pT2 with PSM had...... a 3.1-fold increased risk of BR compared to margin negative patients. Patients with pT2 apical and non-apical PSM had a 5-year biochemical recurrence-free survival of 84.9% (95% CI: 77.6-92.2%) and 78.6% (95% CI: 71.3-85.9%), respectively. In multivariate analysis, pT2 apical and non-apical PSM...

  5. Retreatment of endodontically failed tooth with wide-open apex using platelet rich fibrin membrane as matrix and an apical plug of Biodentine™

    Directory of Open Access Journals (Sweden)

    Ajinkya Mansing Pawar

    2015-01-01

    Full Text Available The primary reason for an endodontic failure is the persistence or regrowth of bacteria within the root canal system, and such cases require retreatment. The tooth root development and closure of its apex occurs till 3 years after the eruption. Traumatic injuries during this development period result in endodontic complications. While dealing with a tooth, with an open apex the prime objective was eliminating bacteria from the root canal system with minimum irritation to the periapical tissues and induction of apical closure to produce favorable conditions and to confine the root canal filling within the canal space. Traditionally as supported by literature multiple dressings of calcium hydroxide medicament were advocated to induce apical barrier formation followed by an evolution of the apical artificial barrier technique where the mineral trioxide aggregate (MTA was used. Recently introduced Biodentine™ is similar to MTA with its basic composition, which can be used as its substitute. The main difficulty associated while treating teeth with wide-open apices are preventing the overfilling of the restorative materials that serve as an artificial barrier. Use of a matrix overcomes this challenge. Platelet-rich fibrin (PRF a matrix of autologous fibrin, embedded with a large quantity of platelet and leukocyte cytokines during centrifugation can be successfully used as an apical membrane. The present case, reports a novel procedure of apexification of endodontically failed central incisor with open apex using PRF as apical membrane and Biodentine™.

  6. Comparative micro-computed tomography evaluation of apical root canal transportation with the use of ProTaper, RaCe and Safesider systems in human teeth.

    Science.gov (United States)

    Ceyhanli, Kadir T; Erdilek, Necdet; Tatar, Ilkan; Cetintav, Bekir

    2014-04-01

    The aim of this study was to compare apical centring ability of nickel titanium (NiTi) ProTaper, RaCe and mainly stainless steel Safesider systems using micro-computed tomography. Thirty freshly extracted mandibular molars with two separate mesial canals and separate foramina were used for the study. Mesial roots were embedded in acrylic resin and instrumented with the ProTaper, RaCe or Safesider systems. Root canal transportation and centring ability of the instruments were evaluated using superimposed micro-computed tomography images of the apical 4 mm of the roots taken at 1 mm intervals. One-way analysis of variance and post hoc Tukey's tests were performed to compare apical transportations. Significant differences were observed between groups at the apical 1, 2 and 3 mm levels (P ProTaper instruments caused more apical root canal transportation than did RaCe instruments at apical 3 mm (P = 0.045). NiTi instrumentation systems showed better centring ability than the mainly stainless steel Safesider system because of the flexible structure of the NiTi alloy.

  7. Evaluation of apical microleakage of teeth sealed with four different root canal sealers Avaliação da microinfiltração apical em dentes obturados com quatro diferentes cimentos endodônticos

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    Fábio Dultra

    2006-10-01

    Full Text Available OBJECTIVES: to compare the apical sealing ability of four root canal sealers. MATERIAL AND METHODS: forty extracted human maxillary canines were instrumented 1 mm short of the anatomical apex and randomly assigned to four groups (n=10, according to the root canal sealer used for obturation: Endofill, AH Plus, EndoREZ and Epiphany. Root canals were obturated with gutta-percha points, except for the Epiphany group, in which resin points (Resilon were used. The teeth were immersed in India ink for seven days and clarified using methyl salicylate. The extent of apical dye penetration was measured with a measuroscope in all aspects of the canal. RESULTS: AH Plus (0.02 mm ± 0.07, Epiphany (0.00 mm ± 0.00 and EndoREZ (0.32 mm ± 0.62 did not differ statistically to each other (p>0.01. EndoFill presented the highest dye penetration mean (0.83 mm ± 0.73 and was statistically different from the other sealers (pOBJETIVOS: comparar a capacidade de selamento apical de quatro cimentos endodônticos. MÉTODOS: quarenta caninos superiores humanos extraídos foram instrumentados 1 mm aquém do ápice anatômico e distribuídos aleatoriamente em quatro grupos (n=10, de acordo com o cimento endodôntico utilizado para a obturação: Endofill, AH Plus, EndoREZ e Epiphany. Os canais radiculares foram obturados pela técnica da condensação lateral com os cimentos e com cones de guta-percha, exceto o grupo do Epiphany, no qual os cones de resina (Resilon foram utilizados. Os dentes foram imersos em nanquim por sete dias e submetidos ao processo de diafanização e, então, clarificados empregando-se o salicilato de metila. A extensão de penetração via apical do corante foi medida por meio de um microscópio de mensuração em todas as faces do terço apical. RESULTADOS: AH Plus (0,02 mm ± 0,07, Epiphany (0,00 mm ± 0,00 e EndoREZ (0,32 mm ± 0,62 não diferiram estatisticamente entre si (p>0,01. EndoFill apresentou a maior média de penetração do corante (0

  8. Cimentos endodônticos - selamento marginal apical imediato e após armazenamento de seis meses Endodontic cements - immediate apical sealing and after a six-month storage

    Directory of Open Access Journals (Sweden)

    Marcia Carneiro VALERA

    1998-10-01

    Full Text Available Este trabalho avaliou o selamento marginal apical de canais radiculares obturados com os cimentos endodônticos Sealapex, Apexit, Sealer 26 e Ketac Endo. Utilizaram-se 136 raízes, cujos canais radiculares, após o preparo biomecânico, foram obturados pela técnica da condensação lateral ativa com os cimentos em estudo. Metade das amostras, imediatamente após as obturações, foram imersas na solução de azul de metileno a 2% e a outra metade após 6 meses de armazenamento em plasma sangüíneo humano. Observou-se que os cimentos Sealapex e Sealer 26 apresentaram infiltrações médias estatisticamente iguais entre si e menores que as observadas para os demais cimentos (p The aim of this study was to verify the apical sealing of root canals obturated with Sealapex, Apexit, Sealer 26, and Ketac Endo cements. A hundred and thirty six dental roots were used for the experiment. After biomechanical preparation and lateral condensation filling, half of the roots were placed in human blood plasma storage medium for 6 months. The remaining samples were immediately placed in methylene blue, under a temporary vacuum, and after one week the amount of dye penetration measured. The stored samples were similarly treated after the 6-month storage period. Statistical analysis of the results revealed that the groups obturated with Sealapex and Sealer 26 showed the smallest amount of apical leakage (p < 0.05. There were significant differences in the amount of dye penetration after 6 months of storage (1.275 mm, when compared to the results found without storage (0.829 mm (p < 0.05.

  9. The influence of two reciprocating single-file and two rotary-file systems on the apical extrusion of debris and its biological relationship with symptomatic apical periodontitis. A systematic review and meta-analysis.

    Science.gov (United States)

    Caviedes-Bucheli, J; Castellanos, F; Vasquez, N; Ulate, E; Munoz, H R

    2016-03-01

    This systematic review and meta-analysis investigated the influence of the number of files (full-sequence rotary-file versus reciprocating single-file systems) used during root canal preparation on the apical extrusion of debris and its biological relationship with the occurrence of symptomatic apical periodontitis. An extensive literature research was carried out in the Medline, ISI Web of Science and Cochrane databases, for relevant articles with the keyword search strategy. Based on inclusion and exclusion criteria, two reviewers independently rated the quality of each study determining the level of evidence of the articles selected. The primary outcome for the meta-analysis was determined by the amount of debris extruded into the periapical tissue during root canal preparation with multiple- or single-file systems in four laboratory studies. Analysis of in vivo release of neuropeptides (SP and CGRP) after root canal preparation with single- or multiple-file systems was also carried out. Amongst the 128 articles initially found, 113 were excluded for being nonrelevant or not fulfilling the selection criteria. Another four articles were excluded after methodology evaluation. Finally, nine laboratory studies and two in vivo studies were included in the systematic review. Four of the laboratory studies were further included for meta-analysis that revealed greater debris extrusion after the use of single-file techniques when compared to multiple-file systems. Analysis of in vivo neuropeptide expression in the periodontal ligament suggests that the design of the instrument is more important than the number of files used. Both rotary and reciprocating single-file systems generate apical extrusion of debris in laboratory studies, or expression of neuropeptides in vivo. Available evidence is limited, but supports the fact that this inflammatory reaction is not influenced by the number of files but the type of movement and the instrument design.

  10. Transcriptional profiling of the pea shoot apical meristem reveals processes underlying its function and maintenance

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    Singh Mohan B

    2008-06-01

    Full Text Available Abstract Background Despite the importance of the shoot apical meristem (SAM in plant development and organ formation, our understanding of the molecular mechanisms controlling its function is limited. Genomic tools have the potential to unravel the molecular mysteries of the SAM, and legume systems are increasingly being used in plant-development studies owing to their unique characteristics such as nitrogen fixation, secondary metabolism, and pod development. Garden pea (Pisum sativum is a well-established classic model species for genetics studies that has been used since the Mendel era. In addition, the availability of a plethora of developmental mutants makes pea an ideal crop legume for genomics studies. This study aims to utilise genomics tools in isolating genes that play potential roles in the regulation of SAM activity. Results In order to identify genes that are differentially expressed in the SAM, we generated 2735 ESTs from three cDNA libraries derived from freshly micro-dissected SAMs from 10-day-old garden peas (Pisum sativum cv Torsdag. Custom-designed oligonucleotide arrays were used to compare the transcriptional profiles of pea SAMs and non-meristematic tissues. A total of 184 and 175 transcripts were significantly up- or down-regulated in the pea SAM, respectively. As expected, close to 61% of the transcripts down-regulated in the SAM were found in the public database, whereas sequences from the same source only comprised 12% of the genes that were expressed at higher levels in the SAM. This highlights the under-representation of transcripts from the meristematic tissues in the current public pea protein database, and demonstrates the utility of our SAM EST collection as an essential genetic resource for revealing further information on the regulation of this developmental process. In addition to unknowns, many of the up-regulated transcripts are known to encode products associated with cell division and proliferation

  11. Apical root resorption during orthodontic treatment with aligners? A retrospective radiometric study

    Science.gov (United States)

    2013-01-01

    Introduction Objective of this study was to investigate the incidence and severity of apical root resorptions (ARR) during orthodontic treatment with aligners. Materials and methods The sample comprised 100 patients (17–75 years of age) with a class I occlusion and anterior crowding before treatment, treated exclusively with aligners (Invisalign®, Align Technologies, Santa Clara, CA, USA). The following teeth were assessed: upper and lower anterior teeth and first molars. Root and crown lengths of a total of 1600 teeth were measured twice in pre- and post-treatment panoramic radiographs. Afterwards, relative changes of the root length during treatment were calculated by a root-crown-ratio taking pre- and post-treatment root and crown lengths into consideration. A reduction of this ratio was considered as a shortening of the initial root length. Additionally, tooth movements of the front teeth were assessed by lateral cephalograms and the 3-dimensonal set up of each patient. Results All patients had a reduction of the pre-treatment root length with a minimum of two teeth. On average 7.36 teeth per patient were affected. 54% of 1600 measured teeth showed no measurable root reduction. A reduction of >0%-10% of the pre-treatment root length was found in 27.75%, a distinct reduction of >10%-20% in 11.94%. 6.31% of all teeth were affected with a considerable reduction of >20%. We found no statistically significant correlation between relative root length changes and the individual tooth, gender, age or sagittal and vertical orthodontic tooth movement; except for extrusion of upper front teeth, which was considered as not clinical relevant due to the small amount of mean 4% ARR. Conclusions The present study is the first analyzing ARR in patients with a fully implemented orthodontic treatment with aligners (i.e. resolving anterior crowding). The variety was high and no clinical relevant influence factor could be detected. A minimum of two teeth with a root length

  12. Effect of the gamma radiation in the metabolic activity of the apical meristem of asparagus (Asparagus officinalis); Efecto de la radiacion gamma en la actividad metabolica del meristemo apical de esparrago (Asparagus officinalis)

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez E, A.; Orozco A, J.A.; Troncoso R, R.; Ojeda C, A.J.; Mercado R, J.N.; Gardea B, A.; Tiznado H, M.E. [Centro de Investigacion en Alimentacion y Desarrollo, A.C. Carretera a la Victoria km. 0.6, A.P. 1735, Hermosillo, Sonora (Mexico); Melendrez A, R. [Universidad de Sonora, A.P. 5-088, Hermosillo, Sonora (Mexico)]. e-mail: aestrada@cascabel.ciad.mx

    2007-07-01

    The asparagus (Asparagus officinalis) is an agricultural product whose production generates a great quantity of wages as well as foreign currencies for the country because a great part of its production is exported to international markets. In direct reason to the high metabolic activity of the apical meristem, this product it possesses a short shelf life under good conditions of commercialization. Due to the above mentioned, the present work had as objective to evaluate the effect of the gamma radiation in the metabolic activity of the apical meristem of turions of asparagus during the postharvest. Turions of asparagus variety Brock of standard quality was treated with gamma radiation to absorbed dose of 1.0, 1.5, 2.0, 2.5 and 3.0 kGy using an irradiator of {sup 60}Co and stored in one controlled temperature camera maintained at 2 C during 8 days. During the experiment, the camera stayed in darkness and under conditions of high relative humidity by means of the water aspersion. Immediately before the one treatment and after 1, 2, 4 and 8 days of storage, the asparagus were sampled to evaluate the breathing speed (VRCG) by means of gas chromatography and scanning differential calorimetry (VRCDB), ethylene production (PE) by means of gas chromatography and production of metabolic heat of the apical meristem of the asparagus by means of scanning differential calorimetry (Q). Its were not found effects due to the gamma radiation in the variables of VRCG, VRCDB and Q. However, for the PE case, it was found that the doses of 1.5 and 2.5 reduced the PE from the first day of storage, while the 3 kGy dose achievement to eliminate completely the ethylene production from the first day of storage. It was concluded that the gamma radiation at the used levels in the present experiment doesn't reduce the metabolic activity of the apical meristem of the turion of asparagus although it can to improve the postharvest quality from the asparagus when reducing the ethylene

  13. DISCINESIA ÁNTERO-APICAL TRANSITORIA O SÍNDROME DE TAKO-TSUBO. PRESENTACIÓN DE UN CASO / Transient antero-apical dyskinesia or tako-tsubo syndrome. A case report

    Directory of Open Access Journals (Sweden)

    Dayán A. García Cuesta

    2011-09-01

    Full Text Available Transient apical ballooning, Tako-tsubo syndrome (and other synonyms, is a clinical condition first described in Japan, and then in other countries, that mimics acute myocardial infarction. Disorders of left ventricular contractility recover within a few weeks. The fatality rate is very low compared with infarction, but it should be known by professionals that see patients with acute coronary syndrome in the emergency department. A patient who was discharged from our department with this diagnosis is presented, and electrocardiographic, echocardiographic and angiographic images are shown.

  14. 重度根尖周病变根尖手术同期冠延长术短期疗效观察%Evaluation of Simultaneous Apical Surgery with Crown Lengthening for Severe Apical Diseases in Short-Term

    Institute of Scientific and Technical Information of China (English)

    吴王喜; 陈筑苏; 周磊; 邱钧琦; 刘芳

    2015-01-01

    Objective:To evaluate simultaneous apical surgery with crown lengthening for severe periapical diseases in short-term.Method:The total of 6 patients from Guangdong Provincial Stomatological Hospital from Sep 2013 to Oct 2014, 6 cases with 23 roots with severe periapical lesions were treated using simultaneous apical surgery with crown lengthening for resecting apical lesion,trimming gingival margin,shaping alveolar,improving clinical crown height at the same time, provisional restorations before and after surgeries,then final restorations 3 months after surgeries.Evaluation of bone healing by CBCT,soft tissue healing by PES.Result:Periapical defect filled with new bone,gingival margins and restorations were stable 6 months after surgeries.Conclusion:Simultaneous apical surgery and crown lengthening is a valid treatment to severe periapical diseases.%目的:观察重度根尖周病变患者根尖手术同期联合冠延长术近期的治疗效果。方法:选择2013年9月-2014年10月广东省口腔医院门诊重度根尖周病患者6例,采用根尖手术切除根尖病灶,同期冠延长手术增加临床冠高度,修整龈缘及牙槽脊外形,术前术后临时修复体成型牙龈,术后3个月软硬组织改建稳定,进行永久冠修复,每治疗阶段CBCT评估骨组织愈合情况,PES红色美学评分标准评价软组织转归情况。结果:根尖周病灶骨缺损区新骨充填,龈缘形态稳定,附着龈质地色泽协调,修复体稳定。结论:根尖手术同期冠延长术治疗重度根尖周病临床可行。

  15. Mineralocorticoids decrease the activity of the apical small-conductance K channel in the cortical collecting duct.

    Science.gov (United States)

    Wei, Yuan; Babilonia, Elisa; Sterling, Hyacinth; Jin, Yan; Wang, Wen-Hui

    2005-11-01

    We used the patch-clamp technique to examine the effect of DOCA treatment (2 mg/kg) on the apical small-conductance K (SK) channels, epithelial Na channels (ENaC), and the basolateral 18-pS K channels in the cortical collecting duct (CCD). Treatment of rats with DOCA for 6 days significantly decreased the plasma K from 3.8 to 3.1 meq and reduced the activity of the SK channel, defined as NP(o), from 1.3 in the CCD of control rats to 0.6. In contrast, DOCA treatment significantly increased ENaC activity from 0.01 to 0.53 and the basolateral 18-pS K channel activity from 0.67 to 1.63. Moreover, Western blot analysis revealed that DOCA treatment significantly increased the expression of the nonreceptor type of protein tyrosine kinase (PTK), cSrc, and the tyrosine phosphorylation of ROMK in the renal cortex and outer medulla. The possibility that decreases in apical SK channel