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Reorganization
Kinds of Reorganization Terms modified by Reorganization Selected AbstractsSPATIOTEMPORAL REORGANIZATION OF GROWTH RATES IN THE EVOLUTION OF ONTOGENYEVOLUTION, Issue 4 2000Miriam L. Zelditch Abstract. Heterochrony, evolutionary changes in rate or timing of development producing parallelism between ontogeny and phylogeny, is viewed as the most common type of evolutionary change in development. Alternative hypotheses such as heterotopy, evolutionary change in the spatial patterning of development, are rarely entertained. We examine the evidence for heterochrony and heterotopy in the evolution of body shape in two clades of piranhas. One of these is the sole case of heterochrony previously reported in the group; the others were previously interpreted as cases of heterotopy. To compare ontogenies of shape, we computed ontogenetic trajectories of shape by multivariate regression of geometric shape variables (i.e., partial warp scores and shape coordinates) on centroid size. Rates of development relative to developmental age and angles between the trajectories were compared statistically. We found a significant difference in developmental rate between species of Serrasalmus, suggesting that heterochrony is a partial explanation for the evolution of body shape, but we also found a significant difference between their ontogenetic transformations; the direction of the difference between them suggests that heterotopy also plays a role in this group. In Pygocentrus we found no difference in developmental rate among species, but we did find a difference in the ontogenies, suggesting that heterotopy, but not heterochrony, is the developmental basis for shape diversification in this group. The prevalence of heterotopy as a source of evolutionary novelty remains largely unexplored and will not become clear until the search for developmental explanations looks beyond heterochrony. [source] Reorganization of the developing human brain after early lesionsDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 8 2007Martin Staudt No abstract is available for this article. [source] Reorganization of cortical hand representation in congenital hemiplegiaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2009Yves Vandermeeren Abstract When damaged perinatally, as in congenital hemiplegia (CH), the corticospinal tract usually undergoes an extensive reorganization, such as the stabilization of normally transient projections to the ipsilateral spinal cord. Whether the reorganization of the corticospinal projections occurring in CH patients is also accompanied by a topographical rearrangement of the hand representations in the primary motor cortex (M1) remains unclear. To address this issue, we mapped, for both hands, the representation of the first dorsal interosseous muscle (1DI) in 12 CH patients by using transcranial magnetic stimulation co-registered onto individual three-dimensional magnetic resonance imaging; these maps were compared with those gathered in age-matched controls (n = 11). In the damaged hemisphere of CH patients, the representation of the paretic 1DI was either found in the hand knob of M1 (n = 5), shifted caudally (n = 5), or missing (n = 2). In the intact hemisphere of six CH patients, an additional, ipsilateral, representation of the paretic 1DI was found in the hand knob, where it overlapped exactly the representation of the non-paretic 1DI. In the other six CH patients, the ipsilateral representation of the paretic 1DI was either shifted caudally (n = 2) or was lacking (n = 4). Surprisingly, in these two subgroups of patients, the representation of the contralateral non-paretic 1DI was found in a more medio-dorsal position than in controls. The present study demonstrates that, besides the well-known reorganization of the corticospinal projections, early brain injuries may also lead to a topographical rearrangement of the representations of both the paretic and non-paretic hands in M1. [source] Metal-Catalyzed Bond Reorganization of 1,3-DiynesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2006Eun Jin Cho Abstract 1,3-Diynes possessing propargylic heteroatom substituents provide functionalized 1,5-dien-3-ynes when catalyzed by platinum and gold. This rearrangement implies the involvement of metallotropic [1,3]-shift of the intermediate alkynyl metal carbene species. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Reorganization of hair follicles in human skin organ culture induced by cultured human follicle-derived cellsEXPERIMENTAL DERMATOLOGY, Issue 8 2005Walter Krugluger Abstract:, Studies of human hair follicle (HF) induction by follicle-derived cells have been limited due to a lack of suitable test systems. In this study, we established a skin organ culture system which supports HF formation by follicle-derived cells. Long-term skin organ cultures were set up from human retroauricular skin specimens and maintained in culture for up to 8 weeks. In vitro expanded human HF-derived cells from the dermal papilla (DP) and the outer root sheath (ORS) were injected together into the skin specimens and evaluated for their ability to induce reorganization of HFs. Macroscopic analysis of the cultured skin specimens demonstrated the growth of velus-like hair after 4 weeks in culture. Histologic evaluation of the cultured skin specimens after 8 weeks of culture revealed multiple miniaturized HFs with sebaceous glands. In addition, cell clusters of various differentiation stages could be demonstrated in serial sections of the cultured skin specimens. Labeling of HF-derived cells with the fluorescence dye CFDA-1 prior to injection suggested a de novo reorganization of HFs out of the injected cells. In conclusion, the study demonstrated HF formation by HF-derived cells in an in vitro skin organ culture model. [source] Corporate Strategy and Gendered Professional Identities: Reorganization and the Struggle for Recognition and PositionsGENDER, WORK & ORGANISATION, Issue 3 2001Bente Rasmussen Will decentralization of responsibilities in services give women service workers at the lower levels of the organization better and more ,professional' jobs and a recognition of their importance in the organization? This article looks at the valuation of so-called women's skills in services in reorganization processes involving dehierarchization and decentralization of responsibilities. Through four cases of reorganized private and public services in Norway it is shown that more focus on customers and decentralization of responsibilities for the services may lead to recognition of gendered skills and an improved position for women service workers at the lowest levels of the organization. When the tasks of the workers are closely linked to the core function of the organization and not dominated by the organization's ,dirty work', the women at the lowest levels may obtain a more ,professional' work role and their work be recognized as important for the organization. [source] Reorganization of a large marine ecosystem due to atmospheric and anthropogenic pressure: a discontinuous regime shift in the Central Baltic SeaGLOBAL CHANGE BIOLOGY, Issue 6 2009CHRISTIAN MÖLLMANN Abstract Marine ecosystems such as the Baltic Sea are currently under strong atmospheric and anthropogenic pressure. Besides natural and human-induced changes in climate, major anthropogenic drivers such as overfishing and anthropogenic eutrophication are significantly affecting ecosystem structure and function. Recently, studies demonstrated the existence of alternative stable states in various terrestrial and aquatic ecosystems. These so-called ecosystem regime shifts have been explained mainly as a result of multiple causes, e.g. climatic regime shifts, overexploitation or a combination of both. The occurrence of ecosystem regime shifts has important management implications, as they can cause significant losses of ecological and economic resources. Because of hysteresis in ecosystem responses, restoring regimes considered as favourable may require drastic and expensive management actions. Also the Baltic Sea, the largest brackish water body in the world ocean, and its ecosystems are strongly affected by atmospheric and anthropogenic drivers. Here, we present results of an analysis of the state and development of the Central Baltic Sea ecosystem integrating hydroclimatic, nutrient, phyto- and zooplankton as well as fisheries data. Our analyses of 52 biotic and abiotic variables using multivariate statistics demonstrated a major reorganization of the ecosystem and identified two stable states between 1974 and 2005, separated by a transition period in 1988,1993. We show the change in Baltic ecosystem structure to have the characteristics of a discontinuous regime shift, initiated by climate-induced changes in the abiotic environment and stabilized by fisheries-induced feedback loops in the food web. Our results indicate the importance of maintaining the resilience of an ecosystem to atmospherically induced environmental change by reducing the anthropogenic impact. [source] Phase Reorganization in Self-Assembled Systems Through Interparticle Material Transfer,ADVANCED MATERIALS, Issue 10 2007C. Moitzi Transfer of material occurs when internally nanostructured emulsion droplets of different composition are mixed. This happens without droplet fusion. As the internal structure is dependent on the composition, the transfer can be followed by monitoring these changes using time-resolved small angle X-ray scattering (SAXS; see figure). [source] Light-Induced Reorganization in Self-Assembled Liquid Crystal Gels: Electrically Switchable Diffraction Gratings,ADVANCED MATERIALS, Issue 17 2003Y. Zhao Electrically switchable diffraction gratings can be formed in the self-assembled cholesteric liquid crystal gels prepared using an azobenzene-containing gelator. The grating formation (see Figure) results from a light-induced reorganization process in these materials, which leads to the removal of the nanometer-sized fibrous aggregates of the gelator from the irradiated area to the non-irradiated area. [source] Reorganization of highly preorganized hosts upon cation complexation: Ab initio study of fluorospherandsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 4 2007Shabaan A. K. Elroby Abstract Fluorospherands (F-spherands) are highly preorganized hosts composed of fluorobenzene or 4-methylfluorobenzene units attached to one another at their 2,6-positions. To understand the intrinsic factors affecting cation complexation, we investigated the complexation behavior between F-spherands and cations using density functional theory (DFT) at the level of B3LYP/6-31G**. The F6-spherand (C6H3F)6, (1) has a highly preorganized spherical cavity, which can encapsulate Li+ and Na+. Its cavity is not big enough for K+ and NH, which prefer external binding. Plausible conformations were studied for F8-spherand (C6H3F)8. Conformer of D2d symmetry (2b) is more stable than that of D4d (2a), in agreement with NMR experiments. The cavity size of F8-spherand is big enough to encapsulate all cations studied. However, the cavity size of 2b is smaller than that of 2a, which resulted in the guest selectivity. Upon complexation, 2b conformation is more stable for Li+ and Na+, while 2a conformation is preferred for larger cations such as K+ and NH. Thus, the ab initio calculations over these highly preorganized fluorospherands give important insights into their host,guest chemistry. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [source] Reorganization of the nervous system during metamorphosis of a hydrozoan planulaINVERTEBRATE BIOLOGY, Issue 3 2000Vicki J. Martina Abstract. Laser scanning confocal microscopy is used to reveal the changes that occur in the RFamide-positive nerve net as a free-swimming, solid hydrozoan planula larva is transformed into a sessile, hollow, young polyp. Seven stages of development in Pennaria tiarella are described: planula competent to metamorphose, attaching planula, disc, pawn, crown, developing polyp, and developed primary polyp. The RFamide-positive nervous system undergoes dramatic reorganization during metamorphosis: (1) larval neurons degenerate; (2) new neurons differentiate and reform a nerve net; and (3) the overall distribution pattern of the nervous system changes. This study confirms earlier observations on RFamide-positive neurons of Hydractinia which also show the loss of these cells after the onset of metamorphosis. [source] Enactment, Sensemaking and Decision Making: Redesign Processes in the 1976 Reorganization of US IntelligenceJOURNAL OF MANAGEMENT STUDIES, Issue 2 2000James Douglas Orton Weick's theories of organizing and sensemaking help enrich the assumptions in the organization design school. This study builds on Weick's theories of sensemaking to illustrate how three fundamental organization design assumptions , dominant variables, causal laws and executive dictates , were found to be restrictive in the explanation of redesign processes in the 1976 reorganization of the US intelligence community. The assumption of dominant variables was challenged by the appearance of a multitude of events, or enactments, which were selected by organization members for further attention. The assumption of causal laws was challenged by the appearance of individual-level cause maps which were filtered, through sensemaking processes, into organization-level workable realities. The assumption of executive dictates was challenged by the appearance of attempts to punctuate redesign processes as organizational decisions. The study suggests value in moving from simple organization design assumptions to more reliable findings drawn from detailed observations of redesign processes. [source] Formation of the chondrocranium of Trachemys scripta (Reptilia: Testudines: Emydidae) and a comparison with other described turtle taxaJOURNAL OF MORPHOLOGY, Issue 2 2007Frank J. Tulenko Abstract Few descriptions of the formation of the chelonian chondrocranium exist. Herein, developmental stages critical to the formation of the chondrocranium of the Red-eared Slider, Trachemys scripta (Testudines: Emydidae), are described and illustrated, with particular attention given to ontogenetic changes that take place in the orbitotemporal region of the skull. Morphological descriptions are based on cleared and double-stained and serially-sectioned embryos. These specimens allowed for a detailed evaluation of the developmental morphology of the trabeculae, interorbital septum, pilae metoptica, taeniae marginalis, acrochordal cartilage, pilae antotica, parachordal cartilages, and crista sellaris. Additionally, the formation of the chondrocranium of T. scripta is compared to those of Chrysemys picta (Emydidae) and Caretta caretta (Chelonidae). Overall, the patterns of formation and remodeling of the chondrocranium are quite similar among these species, with the most conspicuous differences observed in remodeling of the posterior orbital cartilages (specifically, the pila metoptica). Reorganization of these cartilages is discussed briefly in the context of associated extraocular muscles for T. scripta and C. caretta. A prominent intertrabecula is reported in T. scripta, supporting previous observations of this structure in emydid turtles. J. Morphol., 2007. © 2007 Wiley-Liss, Inc. [source] Retinal pigment epithelial cells promote spatial reorganization and differentiation of retina photoreceptorsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 16 2008Olga L. German Abstract Retina differentiation involves the acquisition of a precise layered arrangement, with RPE cells in the first layer in intimate contact with photoreceptors in the second layer. Here, we developed an in vitro coculture model, to test the hypothesis that RPE cells play a pivotal role in organizing the spatial structure of the retina. We cocultured rat retinal neurons with ARPE-19 epithelial cells under various experimental conditions. Strikingly, when seeded over RPE cells, photoreceptors attached to their apical surfaces and proceeded with their development, including the increased synthesis of rhodopsin. Conversely, when we seeded RPE cells over neurons, the RPE cells rapidly detached photoreceptors from their substrata and positioned themselves underneath, thus restoring the normal in vivo arrangement. Treatment with the metalloproteinase inhibitor TIMP-1 blocked this reorganization, suggesting the involvement of metalloproteinases in this process. Reorganization was highly selective for photoreceptors because 98% of photoreceptors but very few amacrine neurons were found to redistribute on top of RPE cells. Interestingly, RPE cells were much more efficient than other epithelial or nonepithelial cells in promoting this reorganization. RPE cells also promoted the growth of photoreceptor axons away from them. An additional factor that contributed to the distal arrangement of photoreceptor axons was the migration of photoreceptor cell bodies along their own neurites toward the RPE cells. Our results demonstrate that RPE and photoreceptor cells interact in vitro in very specific ways. They also show that in vitro studies may provide important insights into the process of pattern formation in the retina. © 2008 Wiley-Liss, Inc. [source] Mobile information retrieval with search results clustering: Prototypes and evaluationsJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 5 2009Claudio Carpineto Web searches from mobile devices such as PDAs and cell phones are becoming increasingly popular. However, the traditional list-based search interface paradigm does not scale well to mobile devices due to their inherent limitations. In this article, we investigate the application of search results clustering, used with some success for desktop computer searches, to the mobile scenario. Building on CREDO (Conceptual Reorganization of Documents), a Web clustering engine based on concept lattices, we present its mobile versions Credino and SmartCREDO, for PDAs and cell phones, respectively. Next, we evaluate the retrieval performance of the three prototype systems. We measure the effectiveness of their clustered results compared to a ranked list of results on a subtopic retrieval task, by means of the device-independent notion of subtopic reach time together with a reusable test collection built from Wikipedia ambiguous entries. Then, we make a cross-comparison of methods (i.e., clustering and ranked list) and devices (i.e., desktop, PDA, and cell phone), using an interactive information-finding task performed by external participants. The main finding is that clustering engines are a viable complementary approach to plain search engines both for desktop and mobile searches especially, but not only, for multitopic informational queries. [source] Reform, Reorganization, and the Renaissance of the Managerial Presidency: The Impact of 9/11 on the Executive EstablishmentPOLITICS & POLICY, Issue 2 2006Richard S. Conley In the wake of 9/11, realigning the human and financial resources of the executive branch to fight the war on terrorism quickly became the defining mission of George W. Bush's transformed presidency. This article assesses the ways in which 9/11 impacted on the executive branch of the U.S. government, using a framework of "punctuated equilibrium" to posit that the terrorist attacks on New York and Washington added considerable force to trends already in motion. September 11 proved a catalyst for significant institutional changes, such as the enhanced role of the vice president in policy making and the reorganization of the federal government and intelligence apparatus. Organizational reforms, driven in a top-down fashion by the White House, reflect President Bush's confidence in the managerial presidency: the notion that preventing future terror threats is effectively a problem of executive control, bureaucratic coordination, and adequate funding. [source] Repairing the human brain after stroke: I. Mechanisms of spontaneous recoveryANNALS OF NEUROLOGY, Issue 3 2008Steven C. Cramer MD Stroke remains a leading cause of adult disability. Some degree of spontaneous behavioral recovery is usually seen in the weeks after stroke onset. Variability in recovery is substantial across human patients. Some principles have emerged; for example, recovery occurs slowest in those destined to have less successful outcomes. Animal studies have extended these observations, providing insight into a broad range of underlying molecular and physiological events. Brain mapping studies in human patients have provided observations at the systems level that often parallel findings in animals. In general, the best outcomes are associated with the greatest return toward the normal state of brain functional organization. Reorganization of surviving central nervous system elements supports behavioral recovery, for example, through changes in interhemispheric lateralization, activity of association cortices linked to injured zones, and organization of cortical representational maps. A number of factors influence events supporting stroke recovery, such as demographics, behavioral experience, and perhaps genetics. Such measures gain importance when viewed as covariates in therapeutic trials of restorative agents that target stroke recovery. Ann Neurol 2008;63:272,287 [source] ChemInform Abstract: Rh(II)-Catalyzed Skeletal Reorganization of 1,6- and 1,7-Enynes Through Electrophilic Activation of Alkynes.CHEMINFORM, Issue 9 2010Kazusa Ota Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Rh(II)-Catalyzed Skeletal Reorganization of 1,6- and 1,7-Enynes Through Electrophilic Activation of Alkynes.CHEMINFORM, Issue 9 2010Kazusa Ota Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Regression and Reorganization of Intonation Between 6 and 23 MonthsCHILD DEVELOPMENT, Issue 2 2006David Snow The purpose of this study was to describe the pattern in which English-speaking children acquire intonation. A second goal was to account for emerging intonation from a theoretical perspective. Six groups of 10 children each between the ages of 6 and 23 months participated in individual play sessions with their mothers and an experimenter. Pitch contours were acoustically analyzed in monosyllabic utterances produced by each child. The observed nonlinear shape of intonation development suggested a linguistically based pattern of regression and reorganization. However, the precocious expression of intonation in the youngest infants also pointed to the role of physiological universals and emotional experience. It is concluded that children's early intonation reflects biological, affective, and linguistic influences. [source] Financial Restructuring in Fresh-Start Chapter 11 ReorganizationsFINANCIAL MANAGEMENT, Issue 4 2009Randall A. Heron We find that firms substantially reduce their debt burden in "fresh-start" Chapter 11 reorganizations, yet they emerge with higher debt ratios than what is typical in their respective industries. While cross-sectional regressions reveal that post-reorganization debt ratios are more in line with the predictions of the static trade-off theory, they also reveal that pre-reorganization debt ratios affect post-reorganization debt ratios. Collectively, these results suggest that impediments in Chapter 11 prevent firms from completely resetting their capital structures. We also find that firms that reported positive operating income leading up to Chapter 11 emerge faster, suggesting that it is quicker to remedy strictly financial distress than economic distress. [source] Mammalian Phosphatidylinositol 4-KinasesIUBMB LIFE, Issue 2 2003Ludwig M. G. Heilmeyer Jr. Abstract Three phosphatidylinositol 4-kinase isoforms, PI4K 230, 92 and 55 have been cloned and sequenced allowing a much wider characterization than the previously employed enzymological typing into type II and III enzymes. PI4K 230 and 92 contain a highly conserved catalytic core, PI4K55 one with a much lower degree of similarity. Candidate kinase motifs, deduced from the protein kinase super family, are absolutely conserved in all isoforms. Kinase activities are described based on their sensitivity and reactivity towards wortmannin, phenylarsine oxide (PAO) and 5,-p-fluorosulfonylbenzoyladenosine (FSBA). Localization of all isoforms in the cell is reported. All enzymes contain nuclear localization and export sequence motifs (NLS and NES) leading to the expectation that they can be transferred to the nucleus. PI4K230 has been found in the nucleolus, PI4K92 in the nucleus, additionally further broadening the function of these enzymes. In the cytoplasm of neuronal cells, PI4K230 is distributed evenly on membranes that are ultra structurally cisterns of the rough endoplasmatic reticulum, outer membranes of mitochondria, multivesicular bodies, and are in close vicinity of synaptic contacts. PI4K92 is functionally characterized as a key enzyme regulating Golgi disintegration/reorganization during mitosis probably via phosphorylation by cyclin-dependent kinases on well-defined sites. PI4K55 is involved in the production of second messengers, diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (InsP3) at the plasma membrane, moreover, in the endocytotic pathway in the cytoplasm. [source] Comparison of basis set effects and the performance of ab initio and DFT methods for probing equilibrium fluctuationsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 2 2007Ross C. Walker Abstract The electronic absorption and emission spectra of large molecules reflect the extent and timescale of electron-vibration coupling and therefore the extent and timescale of relaxation/reorganization in response to a perturbation. In this paper, we present a comparison of the calculated absorption and emission spectra of NADH in liver alcohol dehydrogenase (LADH), using quantum mechanical/molecular mechanical methods, in which we vary the QM component. Specifically, we have looked at the influence of basis set (STO-3G, 3-21G*, 6-31G*, CC-pVDZ, and 6-311G**), as well as the influence of applying the DFT TD-B3LYP and ab initio TD-HF and CIS methods to the calculation of absorption/emission spectra and the reorganization energy (Stokes shift). The ab initio TD-HF and CIS methods reproduce the experimentally determined Stokes shift and spectral profiles to a high level of agreement, while the TD-B3LYP method significantly underestimates the Stokes shift, by 45%. We comment on the origin of this problem and suggest that ab initio methods may be naturally more suited to predicting molecular behavior away from equilibrium geometries. © 2006 Wiley Periodicals, Inc. J Comput Chem 28: 478,490, 2007 [source] Inflammatory cytokines augments TGF-,1-induced epithelial-mesenchymal transition in A549 cells by up-regulating T,R-ICYTOSKELETON, Issue 12 2008Xiangde Liu Abstract Epithelial-mesenchymal transition (EMT) is believed to play an important role in fibrosis and tumor invasion. EMT can be induced in vitro cell culture by various stimuli including growth factors and matrix metalloproteinases. In this study, we report that cytomix (a mixture of IL-1,, TNF-, and IFN-,) significantly enhances TGF-,1-induced EMT in A549 cells as evidenced by acquisition of fibroblast-like cell shape, loss of E-cadherin, and reorganization of F-actin. IL-1, or TNF-, alone can also augment TGF-,1-induced EMT. However, a combination of IL-1, and TNF-, or the cytomix is more potent to induce EMT. Cytomix, but not individual cytokine of IL-1,, TNF-, or IFN-,, significantly up-regulates expression of TGF-, receptor type I (T,R-I). Suppression of T,R-I, Smad2 or Smad3 by siRNA partially blocks EMT induction by cytomix plus TGF-,1, indicating cytomix augments TGF-,1-induced EMT through enhancing T,R-I and Smad signaling. These results indicate that inflammatory cytokines together with TGF-,1 may play an important role in the development of fibrosis and tumor progress via the mechanism of epithelial-mesenchymal transition. Cell Motil. Cytoskeleton 2008. © 2008 Wiley-Liss, Inc. [source] Early molecular events in the assembly of the focal adhesion-stress fiber complex during fibroblast spreadingCYTOSKELETON, Issue 3 2004Baruch Zimerman Cell adhesion to the extracellular matrix triggers the formation of integrin-mediated contact and reorganization of the actin cytoskeleton. Examination of nascent adhesions, formed during early stages of fibroblast spreading, reveals a variety of forms of actin-associated matrix adhesions. These include: (1) small (,1 ,m), dot-like, integrin-, vinculin-, paxillin-, and phosphotyrosine-rich structures, with an F-actin core, broadly distributed over the ventral surfaces of the cells; (2) integrin-, vinculin-, and paxillin-containing "doublets" interconnected by short actin bundles; (3) arrays of actin-vinculin complexes. Such structures were formed by freshly plated cells, as well as by cells recovering from latrunculin treatment. Time-lapse video microscopy of such cells, expressing GFP-actin, indicated that long actin cables are formed by an end-to-end lining-up and apparent fusion of short actin bundles. All these structures were prominent during cell spreading, and persisted for up to 30,60 min after plating. Upon longer incubation, they were gradually replaced by stress fibers, associated with focal adhesions at the cell periphery. Direct examination of paxillin and actin reorganization in live cells revealed alignment of paxillin doublets, forming long and highly dynamic actin bundles, undergoing translocation, shortening, splitting, and convergence. The mechanisms underlying the assembly and reorganization of actin-associated focal adhesions and the involvement of mechanical forces in regulating their dynamic properties are discussed. Cell Motil. Cytoskeleton 58:143,159, 2004. © 2004 Wiley-Liss, Inc. [source] Expression of WASP and Scar1/WAVE1 actin-associated proteins is differentially modulated during differentiation of HL-60 cellsCYTOSKELETON, Issue 4 2003Sophie Launay Abstract The Wiskott-Aldrich Syndrome (WAS) is a disease associated with mutations in the WAS gene and characterised by developmental defects in haematopoietic cells such as myeloid cells. The Wiskott-Aldrich Syndrome protein (WASP)-family includes Scar1 and WASP, which are key regulators of actin reorganization in motile cells. To understand the roles of Scar1 and WASP in myeloid cells and their cytoskeletal control in haematopoietic tissues, we have explored their expression during differentiation of the promyeloid cell line HL-60. Undifferentiated HL-60 cells expressed Scar1 and WASP, and differentiation to neutrophils, induced by retinoic acid or non-retinoid agent treatments, led to a decrease in the level of expression of Scar1, whereas WASP expression was unaffected. Differentiation to monocytes/macrophages, induced by phorbol ester treatment, resulted in a decreased expression of both proteins in the adherent mature cells. Vitamin D3 treatment or cytochalasin D in combination with PMA treatment did not affect WASP expression suggesting that adhesion and cytoskeletal integrity were both essential to regulate WASP expression. Scar1 expression was regulated by differentiation, adhesion, and cytoskeletal integrity. Recently, WASP was found to colocalize with actin in the podosomes. In contrast, we show here that Scar1 did not localize with the podosomes in mature monocytes/macrophages. These observations show for the first time that modulation of Scar1 and WASP expression is a component of the differentiation program of myeloid precursors and indicate that WASP and Scar1 have different roles in mature myeloid cells. Cell Motil. Cytoskeleton 54:274,285, 2003. © 2003 Wiley-Liss, Inc. [source] Calyculin A,induced actin phosphorylation and depolymerization in renal epithelial cellsCYTOSKELETON, Issue 4 2003Luo Gu This study reports actin phosphorylation and coincident actin cytoskeleton alterations in renal epithelial cell line, LLC-PK1. Serine phosphorylation of actin was first observed in vitro after the cell lysate was incubated with phosphatase inhibitors and ATP. Both the phosphorylated actin and actin kinase activities were found in the cytoskeletal fraction. Actin phosphorylation was later detected in living LLC-PK1 cells after incubation with the phosphatase inhibitor calyculin A. Calyculin A,induced actin phosphorylation was associated with reorganization of the actin cytoskeleton, including net actin depolymerization, loss of cell-cell junction and stress fiber F-actin filaments, and redistribution of F-actin filaments in the periphery of the rounded cells. Actin phosphorylation was abolished by 3-h ATP depletion but not by the non-specific kinase inhibitor staurosporine. These results demonstrate that renal epithelial cells contain kinase/phosphatase activities and actin can be phosphorylated in LLC-PK1 cells. Actin phosphorylation may play an important role in regulating the organization of the actin cytoskeleton in renal epithelium. Cell Motil. Cytoskeleton 54:286,295, 2003. © 2003 Wiley-Liss, Inc. [source] Post-karyokinesis centrosome movement leaves a trail of unanswered questionsCYTOSKELETON, Issue 3 2002Young Y. Ou Abstract The centrosome is a complex structure composed of a large number of proteins (pericentriolar material, PCM) usually organized around a pair of centrioles (or a centriole duplex). This structure is capable of nucleating and organizing microtubules, duplication, and motility. In general, episodes of dramatic centrosome movement correlate with periods of cellular reorganization and nowhere is cellular reorganization more apparent, or more important, than in the periods before and after cell division. It is now clear that centrosome movement occurs not only prior to cell division but also at its completion, in concert with cytokinesis. The focus of this review is the newly emerging picture of centrosome activity during the post-karyokinesis period and the role that this activity might play in the transition of cells from mitosis to interphase. Cell Motil. Cytoskeleton 51:123,132, 2002. © 2002 Wiley-Liss, Inc. [source] Achieving a positive outcome to academic reorganizationDEPARTMENT CHAIR, Issue 1 2007Margaret R. Crouse No abstract is available for this article. [source] Atrophic and a Mixed Pattern of Acne Scars Improved With a 1320-nm Nd:YAG LaserDERMATOLOGIC SURGERY, Issue 9 2003Arlene S. Rogachefsky MD Background. Acne scar correction remains a challenge to the dermatologic surgeon. With nonablative laser resurfacing, this correction is imputed to dermal collagen remodeling and acne scar reorganization. Although atrophic acne scars tend to respond to laser treatment, the deeper ice pick and boxcar scars tend to be laser resistant. Objective. To investigate the treatment of atrophic and a mixed pattern of facial acne scars, we evaluated a 1320-nm Nd:YAG laser. Twelve subjects with atrophic facial acne scars (N=6) or a combination of atrophic and pitted, sclerotic, or boxcar scars (N=6) received three laser treatments. Physician and patient acne scar ratings were performed at baseline and at 6 months after the last treatment. Acne scars were rated with a 10-point severity scale. Results. Mean acne scar improvement was 1.5 points on physician assessments (P=0.002) and 2.2 points on patient assessments (P=0.01). Acne scars were rated more severely by patients than by the physician at all intervals. There were no noted complications at 6 months. Conclusion. The 1320-nm Nd:YAG laser is a safe and effective nonablative modality for the improvement of atrophic and a mixed pattern of facial acne scars. [source] | ||||||||||||||||||||||||||||||||||||||||||||||