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Spreading
Kinds of Spreading Terms modified by Spreading Selected AbstractsPatterns of Detection of Superficial Spreading and Nodular-Type Melanoma: A Multicenter Italian StudyDERMATOLOGIC SURGERY, Issue 11 2004Paolo Carli Background. Nodular histotype represents the condition that is mostly associated with diagnosis of thick melanoma. Objective. The objectives were to evaluate variables associated with and pattern of detection of nodular melanomas and to investigate variables associated with early diagnosis in accordance with histotype (nodular vs. superficial spreading melanomas). Methods. From the original data set of 816 melanomas, all the invasive lesions classified as superficial spreading (n=500) and nodular (n=93) melanomas were considered for the study. A multivariate logistic analysis was performed. Results. Nodular melanomas did not significantly differ from superficial spreading melanomas regarding sex, anatomic site, number of whole-body nevi, and the presence of atypical nevi. As expected, nodular melanomas were represented by a higher percentage of thick (>2 mm) lesions compared to superficial spreading melanomas (64.5% vs. 9.6%, p<0.001). The pattern of detection significantly differed between nodular and superficial spreading melanomas, the former being more frequently self-detected (44.1% vs. 38.0%) or detected by the family doctor (34.4% vs. 11.4%). Female sex, high level of education, and detection made by a dermatologist had an independent, protective effect against late (>1 mm in thickness) diagnosis in superficial spreading melanomas. No protective variable associated with nodular melanomas was found. Conclusion. Patterns of detection for nodular melanomas significantly differ from those for superficial spreading melanomas. For superficial spreading, but not for nodular, melanomas, variables associated with protective effect against late diagnosis can be identified. [source] Cell survival and apoptosis-related molecules in cancer cells in effusions: A comprehensive reviewDIAGNOSTIC CYTOPATHOLOGY, Issue 8 2009Lilach Kleinberg Ph.D. Abstract Spreading of cancer cells to effusions is a manifestation of advanced disease, for which the chances of achieving cure using conventional treatment are low. This emphasizes both the importance of improving early detection and the need for developing targeted therapy modes. Such approaches should be based on characterization of the antiapoptotic, survival and drug resistance mechanisms of the metastatic cells in addition to analysis of the primary tumor. This review presents current knowledge regarding the expression and clinical role of cell survival and apoptosis-related molecules in nonhematological cancers in effusions. Differences in the anatomic site-related expression and clinical role of these proteins are additionally discussed. The data presented highlight the complexity of the multiple molecular pathways that mediate tumor cell survival within the serosal cavities. Diagn. Cytopathol. 2009. © 2009 Wiley-Liss, Inc. [source] Role of venom and ovarian proteins in immune suppression of Ostrinia furnacalis (Lepidoptera: Pyralidae) larvae parasitized by Macrocentrus cingulum (Hymenoptera: Braconidae), a polyembryonic parasitoidINSECT SCIENCE, Issue 2 2007YONG LI Abstract Venom and ovarian proteins in braconid and ichneumonid wasps play an important role in the successful parasitism of their host, especially for immune suppression immediately after oviposition. In this study, we compared the effect of venom and ovarian proteins collected from the female wasps of Macrocentrus cingulum, a polyembryonic parasitoid of the larvae of Ostrinia funacalis, on the encapsulation capacity of Sephadex A-25 beads at 4 h and 24 h post-injection both in vivo and in vitro. The results showed that the ovarian proteins significantly interfered with the encapsulation capacity of hemocytes in a dose-dependent manner. Spreading and viability of hemocytes in O. furnacalis was not disrupted by venom and ovarian proteins at various concentrations injected. It seems likely that the ovarian proteins from M. cingulum play a role in suppressing the encapsulation capacity of host hemocytes. [source] A New Scenario in Probe Local Oxidation: Transient Pressure-Wave-Assisted Ionic Spreading and Oxide Pattern Formation,ADVANCED MATERIALS, Issue 18 2007N. Xie A new mechanism based on transient shock-wave-assisted lateral ionic spreading and oxide growth is reported for atomic force microscopy probe local oxidation (see figure). Transitory high pressure waves generated in the nanoscopic tip,sample junction significantly extend the distribution of hydroxyl oxidants to facilitate micrometer-scale disk-oxide growth on a silicon substrate. The results show that shock propagation may be a general phenomenon in AFM nanolithography. [source] Orientation-Selective Incorporation of Transmembrane F0F1 ATP Synthase Complex from Micrococcus luteus in Polymer-Supported MembranesMACROMOLECULAR BIOSCIENCE, Issue 11 2008Murat Tutus Abstract We report the vectorial incorporation of a highly asymmetric F0F1 ATP synthase complex from Micrococcus luteus into polymer-supported membranes. Dynamic light scattering and cryo electron microscopy confirm that the use of weak surfactants (bile acid) allows for the non-disruptive protein incorporation into lipid vesicles. Spreading of vesicles with ATP synthase onto a cellulose support results in a homogeneous distribution of proteins, in contrast to a patchy image observed on bare glass slides. The orientation of ATP synthase can be identified using an antibody to the ATP binding site as well as from topographic profiles of the surface. The method to "align" transmembrane proteins in supported membranes would open a possibility to quantify protein functions in biomimetic model systems. [source] The p110, Isoform of PI3K Differentially Regulates ,1 and ,2 Integrin-Mediated Monocyte Adhesion and Spreading and Modulates DiapedesisMICROCIRCULATION, Issue 6 2006ALEXANDER M. FERREIRA ABSTRACT Objective: Leukocyte diapedesis is misregulated in inflammatory disease and depends on the binding of monocytic LFA-1 and VLA-4 to endothelial ICAM-1 and VCAM-1, respectively. The authors hypothesized that these different molecular interactions elicit specific signaling cascades within monocytes regulating specific steps in adhesion, motility, and diapedesis. Methods: The authors employed the PI3K p110, catalytic subunit specific inhibitor IC87114 (2 , M) and the broad-spectrum PI3K inhibitory agents LY294002 (50 , M) and wortmannin (100 nM), to examine the role of PI3K, in monocyte diapedesis through endothelial monolayers and its role in monocyte adhesion and spreading upon carpets of ICAM-1 or VCAM-1. They further explored the effects of PI3K, inhibition on the activation state of , 1 and , 2 integrins with immunocytochemistry and flow cytometry. Results: In human peripheral blood monocytes IC87114 was as effective as wortmannin and LY294002 at inhibiting diapedesis, however, in THP-1 cells LY294002 and wortmannin caused a 5-fold reduction in diapedesis, while IC87114 only decreased diapedesis 2-fold. PI3K, activity was specifically required for THP-1 cell adhesion and spreading on VCAM-1, but not on ICAM-1 protein substrates. Flow cytometric analysis demonstrated that PI3K, inhibition decreased the amount of conformationally active , 1-integrins, while having no effect on the prevalence of conformationally active , 2-integrins expressed on the cell surface. In addition, PI3K, inhibition resulted in a 4-fold decrease in the activation state of Rac-1 and Cdc42. Conclusions: These results demonstrate the specific necessity of PI3K, in regulating monocytic integrin activation and the general role of PI3K signaling during diapedesis, implicating PI3K as a target for therapeutic intervention. [source] Nucleotides and epidermal growth factor induce parallel cytoskeletal rearrangements and migration in cultured adult murine neural stem cellsACTA PHYSIOLOGICA, Issue 2 2010I. Grimm Abstract Aim:, The adult subventricular zone (SVZ) contains neural stem cells that generate neuroblasts migrating to the olfactory bulb (OB) and differentiating into interneurones. The molecular cues controlling essential functions within the neurogenesis pathway such as proliferation, short and long distance migration, functional integration and cell survival are poorly understood. We have previously shown that cultured adult neural stem cells express a considerable variety of nucleotide receptors and that nucleotides and epidermal growth factor (EGF) induce converging intracellular signalling pathways that carry potential for synergism in the control of neural stem cell proliferation and cell survival. Here we investigate the role of EGF and the nucleotides ATP, ADP,S and UTP in neural stem cell migration. Methods:, Neural stem cells were prepared from adult mice and subjected to adherent culture. Labelling of F-actin was performed with tetramethylrhodamine isothiocyanate-phalloidin. Images were processed for quantitative evaluation of fluorescence labelling. Agonist-induced phosphorylation of AKT and focal adhesion kinase was analysed by quantitative Western blotting. Agonist-dependent cell migration was assayed using 48-well microchemotaxis chambers. Results:, Nucleotides and EGF induce the formation of stress fibres, an increase in the cortical actin cytoskeleton and in cell spreading. This is associated with increased phosphorylation of AKT and focal adhesion kinase. Using microchemotaxis chambers we demonstrate a parallel increase in cell migration. Conclusion:, Our results suggest that nucleotides and EGF acting as paracrine or autocrine signalling substances can be of relevance for structuring and maintaining the cytoarchitecture of the SVZ and the stream of neuroblasts migrating to the OB. [source] Novel interactors and a role for supervillin in early cytokinesis,CYTOSKELETON, Issue 6 2010Tara C. Smith Abstract Supervillin, the largest member of the villin/gelsolin/flightless family, is a peripheral membrane protein that regulates each step of cell motility, including cell spreading. Most known interactors bind within its amino (N)-terminus. We show here that the supervillin carboxy (C)-terminus can be modeled as supervillin-specific loops extending from gelsolin-like repeats plus a villin-like headpiece. We have identified 27 new candidate interactors from yeast two-hybrid screens. The interacting sequences from 12 of these proteins (BUB1, EPLIN/LIMA1, FLNA, HAX1, KIF14, KIFC3, MIF4GD/SLIP1, ODF2/Cenexin, RHAMM, STARD9/KIF16A, Tks5/SH3PXD2A, TNFAIP1) co-localize with and mis-localize EGFP-supervillin in mammalian cells, suggesting associations in vivo. Supervillin-interacting sequences within BUB1, FLNA, HAX1, and MIF4GD also mimic supervillin over-expression by inhibiting cell spreading. Most new interactors have known roles in supervillin-associated processes, e.g. cell motility, membrane trafficking, ERK signaling, and matrix invasion; three (KIF14, KIFC3, STARD9/KIF16A) have kinesin motor domains; and five (EPLIN, KIF14, BUB1, ODF2/cenexin, RHAMM) are important for cell division. GST fusions of the supervillin G2-G3 or G4-G6 repeats co-sediment KIF14 and EPLIN, respectively, consistent with a direct association. Supervillin depletion leads to increased numbers of bi- and multi-nucleated cells. Cytokinesis failure occurs predominately during early cytokinesis. Supervillin localizes with endogenous myosin II and EPLIN in the cleavage furrow, and overlaps with the oncogenic kinesin, KIF14, at the midbody. We conclude that supervillin, like its interactors, is important for efficient cytokinesis. Our results also suggest that supervillin and its interaction partners coordinate actin and microtubule motor functions throughout the cell cycle. © 2010 Wiley-Liss, Inc. [source] The effect of combined hypergravity and microgrooved surface topography on the behaviour of fibroblastsCYTOSKELETON, Issue 7 2006W. A. Loesberg Abstract This study evaluated in vitro the differences in morphological behaviour between fibroblast cultured on smooth and microgrooved substrata (groove depth: 1 ,m, width: 1, 2, 5, 10 ,m), which undergo artificial hypergravity by centrifugation (10, 24 and 50 g; or 1 g control). The aim of the study was to clarify which of these parameters was more important to determine cell behaviour. Morphological characteristics were investigated using scanning electron microscopy and fluorescence microscopy in order to obtain qualitative information on cell spreading and alignment. Confocal laser scanning microscopy visualised distribution of actin filaments and vinculin anchoring points through immunostaining. Finally, expression of collagen type I, fibronectin, and ,1 - and ,1 -integrin were investigated by PCR. Microscopy and image analysis showed that the fibroblasts aligned along the groove direction on all textured surfaces. On the smooth substrata (control), cells spread out in a random fashion. The alignment of cells cultured on grooved surfaces increased with higher g-forces until a peak value at 25 g. An ANOVA was performed on the data, for all main parameters: topography, gravity force, and time. In this analysis, all parameters proved significant. In addition, most gene levels were reduced by hypergravity. Still, collagen type 1 and fibronectin are seemingly unaffected by time or force. From our data it is concluded that the fibroblasts primarily adjust their shape according to morphological environmental cues like substratum surface whilst a secondary, but significant, role is played by hypergravity forces. Cell Motil. Cytoskeleton 2006. © 2006 Wiley-Liss, Inc. [source] Myoblast attachment and spreading are regulated by different patterns by ubiquitous calpainsCYTOSKELETON, Issue 4 2006Germain Mazères Abstract The calcium-dependent proteolytic system is a large family of well-conserved ubiquitous and tissue-specific proteases, known as calpains, and an endogenous inhibitor, calpastatin. Ubiquitous calpains are involved in many physiological phenomena, such as the cell cycle, muscle cell differentiation, and cell migration. This study investigates the regulation of crucial steps of cell motility, myoblast adhesion and spreading, by calpains. Inhibition of each ubiquitous calpain isoform by antisense strategy pinpointed the involvement of each of these proteases in myoblast adhesion and spreading. Moreover, the actin cytoskeleton and microtubules were observed in transfected cells, demonstrating that each ubiquitous calpain could be involved in the actin fiber organization. C2C12 cells with reduced ,- or m-calpain levels have a rounded morphology and disorganized stress fibers, but no modification in the microtubule cytoskeleton. Antisense strategy directed against MARCKS, a calpain substrate during C2C12 migration, showed that this protein could play a role in stress fiber polymerization. A complementary proteomic analysis using C2C12 cells over-expressing calpastatin indicated that two proteins were under-expressed, while six, which are involved in the studied phenomena, were overexpressed after calpain inhibition. The possible role of these proteins in adhesion, spreading, and migration was discussed. Cell Motil. Cytoskeleton 63: 2006. © 2006 Wiley-Liss, Inc. [source] CSF-1 and PI 3-kinase regulate podosome distribution and assembly in macrophagesCYTOSKELETON, Issue 3 2006Ann P. Wheeler Abstract Podosomes are actin-rich adhesive foci found in several cell types, including macrophages. They have a core containing actin and actin-binding proteins and a peripheral ring of integrins and associated proteins. We show that podosomes are abundant in polarized mouse bone marrow-derived macrophages (BMM) and are found primarily in lamellae. We investigated the effects of CSF-1, which induces membrane ruffling, cell spreading, and subsequent polarization and migration, on podosome formation. CSF-1 induces a transient increase in podosome number and enhances the formation of circular arrays of podosomes. Conversely, CSF-1 withdrawal leads to a reduction in podosomes and a decrease in polarized cells. The PI 3-kinase inhibitor LY294002 induces loss of podosomes together with rapid retraction of lamellae and loss of polarity. Our results indicate that CSF-1 acts via PI 3-kinase to enhance podosome assembly and that this is linked to macrophage polarization. Cell Motil. Cytoskeleton, 2006. © 2006 Wiley-Liss, Inc. [source] RNAi knockdown of the focal adhesion protein TES reveals its role in actin stress fibre organisationCYTOSKELETON, Issue 3 2005Elen Griffith Abstract TES was originally identified as a candidate tumour suppressor gene and has subsequently been found to encode a novel focal adhesion protein. As well as localising to cell-matrix adhesions, TES localises to cell-cell contacts and to actin stress fibres. TES interacts with a variety of cytoskeletal proteins including zyxin, mena, VASP, talin and actin. There is evidence that TES may function in actin-dependent processes as overexpression of TES results in increased cell spreading and decreased cell motility. Together with TES's interacting partners, these data suggest that TES might be involved in regulation of the actin cytoskeleton. Here, for the first time, we have used RNAi to successfully knockdown TES in HeLa cells and we demonstrate that loss of TES from focal adhesions results in loss of actin stress fibres. Similarly, and as previously reported, RNAi-mediated knockdown of zyxin results in loss of actin stress fibres. TES siRNA treated cells show reduced RhoA activity, suggesting that the Rho GTPase pathway may be involved in the TES RNAi-induced loss of stress fibres. We have also used RNAi to examine the requirement of TES and zyxin for each other's localisation at focal adhesions, and we propose a hierarchy of recruitment, with zyxin being first, followed by VASP and then TES. Cell Motil. Cytoskeleton 60:140,152, 2005. © 2005 Wiley-Liss, Inc. [source] Vinculin is proteolyzed by calpain during platelet aggregation: 95 kDa cleavage fragment associates with the platelet cytoskeletonCYTOSKELETON, Issue 4 2004Katherine Serrano Abstract The focal adhesion protein vinculin contributes to cell attachment and spreading through strengthening of mechanical interactions between cell cytoskeletal proteins and surface membrane glycoproteins. To investigate whether vinculin proteolysis plays a role in the influence vinculin exerts on the cytoskeleton, we studied the fate of vinculin in activated and aggregating platelets by Western blot analysis of the platelet lysate and the cytoskeletal fractions of differentially activated platelets. Vinculin was proteolyzed into at least three fragments (the major one being ,95 kDa) within 5 min of platelet activation with thrombin or calcium ionophore. The 95 kDa vinculin fragment shifted cellular compartments from the membrane skeletal fraction to the cortical cytoskeletal fraction of lysed platelets in a platelet aggregation-dependent manner. Vinculin cleavage was inhibited by calpeptin and E64d, indicating that the enzyme responsible for vinculin proteolysis is calpain. These calpain inhibitors also inhibited the translocation of full-length vinculin to the cytoskeleton. We conclude that cleavage of vinculin and association of vinculin cleavage fragment(s) with the platelet cytoskeleton is an activation response that may be important in the cytoskeletal remodeling of aggregating platelets. Cell Motil. Cytoskeleton 58:242,252, 2004. © 2004 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] Patterns of Detection of Superficial Spreading and Nodular-Type Melanoma: A Multicenter Italian StudyDERMATOLOGIC SURGERY, Issue 11 2004Paolo Carli Background. Nodular histotype represents the condition that is mostly associated with diagnosis of thick melanoma. Objective. The objectives were to evaluate variables associated with and pattern of detection of nodular melanomas and to investigate variables associated with early diagnosis in accordance with histotype (nodular vs. superficial spreading melanomas). Methods. From the original data set of 816 melanomas, all the invasive lesions classified as superficial spreading (n=500) and nodular (n=93) melanomas were considered for the study. A multivariate logistic analysis was performed. Results. Nodular melanomas did not significantly differ from superficial spreading melanomas regarding sex, anatomic site, number of whole-body nevi, and the presence of atypical nevi. As expected, nodular melanomas were represented by a higher percentage of thick (>2 mm) lesions compared to superficial spreading melanomas (64.5% vs. 9.6%, p<0.001). The pattern of detection significantly differed between nodular and superficial spreading melanomas, the former being more frequently self-detected (44.1% vs. 38.0%) or detected by the family doctor (34.4% vs. 11.4%). Female sex, high level of education, and detection made by a dermatologist had an independent, protective effect against late (>1 mm in thickness) diagnosis in superficial spreading melanomas. No protective variable associated with nodular melanomas was found. Conclusion. Patterns of detection for nodular melanomas significantly differ from those for superficial spreading melanomas. For superficial spreading, but not for nodular, melanomas, variables associated with protective effect against late diagnosis can be identified. [source] Gastrin-Releasing Peptide, a Bombesin-like Neuropeptide, Promotes Cutaneous Wound HealingDERMATOLOGIC SURGERY, Issue 4 2002Yuji Yamaguchi MD Background. Little is known about the effects of neuropeptides on wound healing. Objective. To investigate the effect of gastrin-releasing peptide (GRP), one of the bombesin-like neuropeptides, on wound healing. Methods. The effects of GRP on cultured keratinocyte proliferation and migration were measured by BrdU uptake and in vitro scratch assay, respectively. Various concentrations of GRP ointments (0, 10,9, 10,8, 10,7, 10,6 M) were topically applied to 1.0 mm wounds on porcine flanks. Results. GRP stimulated keratinocyte growth and locomotion in a dose-dependent manner. Topical administration of GRP accelerated macroscopic epidermal regeneration in a dose-dependent manner, as measured by planimetry. Histologic studies also showed that GRP promoted reepithelialization, including epidermal thickness as well as superficial skin coverage. conclusion. Topical use of GRP may clinically accelerate wound healing of burns, injuries, chronic ulcers, and skin graft donor sites through the enhancement of keratinocyte growth and spreading. [source] The Rise of Kenyan Supermarkets and the Evolution of their Horticulture Product Procurement SystemsDEVELOPMENT POLICY REVIEW, Issue 6 2004David Neven Supermarkets are rapidly penetrating urban food retail in Kenya and spreading well beyond their initially tiny market niche among the urban middle class into the food markets of lower-income groups. Having penetrated processed and staple food markets much earlier and faster than fresh foods, they have recently begun to make inroads into the fresh fruits and vegetables category. Supermarkets in Kenya already buy about half the volume of produce exported, and thus represent a significant new ,dynamic market' opportunity for farmers. The important changes in their procurement systems bring significant opportunities and challenges for small farmers, and have implications for agricultural diversification and rural development programmes and policies. [source] Neural tube defects and impaired neural progenitor cell proliferation in G,1 -deficient miceDEVELOPMENTAL DYNAMICS, Issue 4 2010Hiroaki Okae Abstract Heterotrimeric G proteins are well known for their roles in signal transduction downstream of G protein,coupled receptors (GPCRs), and both G, subunits and tightly associated G,, subunits regulate downstream effector molecules. Compared to G, subunits, the physiological roles of individual G, and G, subunits are poorly understood. In this study, we generated mice deficient in the G,1 gene and found that G,1 is required for neural tube closure, neural progenitor cell proliferation, and neonatal development. About 40% G,1,/, embryos developed neural tube defects (NTDs) and abnormal actin organization was observed in the basal side of neuroepithelium. In addition, G,1,/, embryos without NTDs showed microencephaly and died within 2 days after birth. GPCR agonist-induced ERK phosphorylation, cell proliferation, and cell spreading, which were all found to be regulated by G,i and G,, signaling, were abnormal in G,1,/, neural progenitor cells. These data indicate that G,1 is required for normal embryonic neurogenesis. Developmental Dynamics 239:1089,1101, 2010. © 2010 Wiley-Liss, Inc. [source] Membrane dynamics of cleavage furrow closure in Xenopus laevisDEVELOPMENTAL DYNAMICS, Issue 3 2008Michael V. Danilchik Abstract Epithelial membrane polarity develops early in Xenopus development, with membrane inserted along the earliest cleavage furrows by means of localized exocytosis. The added surface constitutes a new basolateral domain important for early morphogenesis. This basolateral surface becomes isolated from the outside by furrow closure, a zippering of adjacent apical,basolateral margins. Time-lapse microscopy of membrane-labeled embryos revealed two distinct kinds of protrusive activity in furrow closure. Early in furrowing, protrusive activity was associated with purse-string contractility along the apical,basolateral margins. Later in furrow progression, a basolateral protrusive zone developed entirely within the new membrane domain, with long motile filopodia extending in contractile bands from the exposed surfaces. Filopodia interacting with opposing cell surfaces across the cleavage furrow appeared to mediate blastomere,blastomere adhesion, contact spreading and lamellipodial protrusion. Interference with these dynamic activities prevented furrow closure, indicating a basic role for both marginal and basolateral protrusive activities in early embryogenesis. Developmental Dynamics 237:565,579, 2008. © 2008 Wiley-Liss, Inc. [source] Eph,ephrin A system regulates murine blastocyst attachment and spreadingDEVELOPMENTAL DYNAMICS, Issue 12 2006Haruko Fujii Abstract Although numerous adhesion molecules are expressed on mammalian endometrial epithelial cells, there have not been any studies of a mechanism to prevent premature attachment of the embryo. In this study, we examined the possible involvement of Eph,ephrin interaction, which can induce repulsive forces. In mice, Eph A1, A2, and A4 were expressed on endometrial epithelial cells and ephrin A1,4 on blastocysts. Reverse transcriptase-polymerase chain reaction showed that mRNA expression of ephrin A1,4 on embryos transiently decreased around the implantation period. Immunohistochemistry demonstrated that the expression of Eph A1 on endometrial epithelial cells and ephrin A1 and A3 expression on embryos decreased at implantation sites. Recombinant Eph A1 reacted with cell the surface of ephrin A-bearing trophectoderm cells. Attachment assays using Eph A1-coated dishes showed that blastocyst attachment was reversibly inhibited by Eph A1. These findings suggest an important role of the Eph,ephrin A system in regulating the initial embryo,maternal contact during the cross-talk period that precedes embryo implantation. Developmental Dynamics 235:3250,3258, 2006. © 2006 Wiley-Liss, Inc. [source] Accelerated neuritogenesis and maturation of primary spinal motor neurons in response to nanofibersDEVELOPMENTAL NEUROBIOLOGY, Issue 8 2010Caitlyn C. Gertz Abstract Neuritogenesis, neuronal polarity formation, and maturation of axons and dendrites are strongly influenced by both biochemical and topographical extracellular components. The aim of this study was to elucidate the effects of polylactic acid electrospun fiber topography on primary motor neuron development, because regeneration of motor axons is extremely limited in the central nervous system and could potentially benefit from the implementation of a synthetic scaffold to encourage regrowth. In this analysis, we found that both aligned and randomly oriented submicron fibers significantly accelerated the processes of neuritogenesis and polarity formation of individual cultured motor neurons compared to flat polymer films and glass controls, likely due to restricted lamellipodia formation observed on fibers. In contrast, dendritic maturation and soma spreading were inhibited on fiber substrates after 2 days in vitro. This study is the first to examine the effects of electrospun fiber topography on motor neuron neuritogenesis and polarity formation. Aligned nanofibers were shown to affect the directionality and timing of motor neuron development, providing further evidence for the effective use of electrospun scaffolds in neural regeneration applications. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 589,603, 2010 [source] NEW APPLICATION OF NARROW BAND IMAGING FOR CHOLANGIOPANCREATOSCOPYDIGESTIVE ENDOSCOPY, Issue 2007Mitsuhiro Kida The usefulness of narrow band imaging (NBI), which is based on the principle that the depth of light penetration depends on its wavelength, has been accepted for evaluating malignant or benign lesions in the pharynx, the upper, and lower gastrointestine. The purpose of the present paper was to investigate NBI for diagnosing biliopancreatic disease. Using NBI it has become easy to detect the surface microstructure of biliary mucosa and subjacent vascular network of the bile duct, and inflammatory scarring stenosis is visualized as a whitish scar and multiple inflammatory red spots. However, bile duct cancer was detected as a stenosis with abnormal subjacent vessels and irregular surface. Concerning pancreatic duct, NBI has clearly shown vascular network and spreading of branch-type intraductal papillary mucinous neoplasm to the main pancreatic duct. In contrast, bile juice has been detected as red fluid and bleeding as black red. Therefore, it is important to flush the biliary system before observing with NBI. [source] Ultrastructural features of the process of wound healing after tail and limb amputation in lizardACTA ZOOLOGICA, Issue 3 2010L. Alibardi Abstract Alibardi, L. 2010. Ultrastructural features of the process of wound healing after tail and limb amputation in lizard.,Acta Zoologica (Stockholm) 91: 306,318 Wound healing and re-epitelization after amputation of tail and limb in lizard have been studied by electron microscopy to understand the cytological base of immunity to infection in this species. After 2 days post-amputation in both limb and tail stumps, numerous granulocytes are accumulated over the stump, and participate to the formation of the scab. Bacteria remain confined to the scab or are engulfed by leukocytes and migrating keratinocytes located underneath the scab. Bacteria are degraded within lysosomes present in these cells and are not observed among mesenchymal cells or in blood vessels of the regenerative blastema. Granulocytes, migrating keratinocytes, and later macrophages form an effective barrier responsible for limiting microbe penetration. The innate immunity in lizard is very effective in natural (dirty) condition and impedes the spreading of infection to inner tissues. While the complete re-epitelization of the tail stump underneath the scab requires 4,7 days, the same process in the limb requires 8,18 or more days post-amputation, depending from the level of amputation and the persistence of a protruding humerus or femurs on the stump surface. This delay produces the permanence of inflammatory cells such as granulocytes and macrophages in the limb stump for a much longer period than in the tail stump, a process that stimulates scarring. [source] The role of soil in the collapse of 18 piers of Hanshin Expressway in the Kobe earthquakeEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 5 2006George Mylonakis Abstract An investigation is presented of the collapse of a 630 m segment (Fukae section) of the elevated Hanshin Expressway during the 1995 Kobe earthquake. The earthquake has, from a geotechnical viewpoint, been associated with extensive liquefactions, lateral soil spreading, and damage to waterfront structures. Evidence is presented that soil,structure interaction (SSI) in non-liquefied ground played a detrimental role in the seismic performance of this major structure. The bridge consisted of single circular concrete piers monolithically connected to a concrete deck, founded on groups of 17 piles in layers of loose to dense sands and moderate to stiff clays. There were 18 spans in total, all of which suffered a spectacular pier failure and transverse overturning. Several factors associated with poor structural design have already been identified. The scope of this work is to extend the previous studies by investigating the role of soil in the collapse. The following issues are examined: (1) seismological and geotechnical information pertaining to the site; (2) free-field soil response; (3) response of foundation-superstructure system; (4) evaluation of results against earlier studies that did not consider SSI. Results indicate that the role of soil in the collapse was multiple: First, it modified the bedrock motion so that the frequency content of the resulting surface motion became disadvantageous for the particular structure. Second, the compliance of soil and foundation altered the vibrational characteristics of the bridge and moved it to a region of stronger response. Third, the compliance of the foundation increased the participation of the fundamental mode of the structure, inducing stronger response. It is shown that the increase in inelastic seismic demand in the piers may have exceeded 100% in comparison with piers fixed at the base. These conclusions contradict a widespread view of an always-beneficial role of seismic SSI. Copyright © 2005 John Wiley & Sons, Ltd. [source] Bank Mergers, Information, Default and the Price of CreditECONOMIC NOTES, Issue 1 2006Margarida Catalão- Lopes This paper addresses the impact of bank mergers on the price of firm credit, through an information channel. It is shown that, as bank mergers imply a wider spreading of information among banks concerning firms' past defaults, they may increase the expected revenue from lending. Therefore, interest rates may decline as long as a sufficiently competitive environment is preserved. A fall in interest rates, in turn, reduces the incentives for firms to strategically default, which reinforces the downward effect on the price of credit. The results are a function of the level of information sharing and of the sensitivity of the default probability to the interest rate. [source] Speciation and Environmental Fate of Chromium in Rivers Contaminated with Tannery EffluentsENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 2 2007J. Dominik Abstract Redox and size speciation of chromium in rivers contaminated with tannery wastewater was carried out to provide insight into its transport and removal mechanisms. Total chromium was determined with Inductively Coupled Plasma-Mass Spectrometry and Cr,(VI) with Catalytic Adsorption Stripping Voltammetry. For the size speciation, particles were retained with a cartridge filter (cut-off 1.2,,m) and the total filterable fraction was further fractionated with Tangential Flow Filtration to determine the concentrations of chromium associated with the High Molecular Weight Colloidal (HMWC), Low Molecular Weight Colloidal (LMWC) and Truly Dissolved (TD) fractions. Two fluvial systems of similar sizes, but located in contrasting climatic zones, were selected for comparison: the Sebou-Fez system in Morocco and Dunajec River-Czorsztyn Reservoir system in Poland. Particulate Cr dominated in the Sebou-Fez system (about 90,%); while in the Dunajec-Czorsztyn system, it represented only 17,53,% of the total chromium in raw water. Still, the partition coefficients [Kd] were of the same magnitude. Chromium,(III) was the only form detected in Sebou-Fez, whereas in Dunajec-Czorsztyn Cr,(VI) was also present with its proportion increasing downstream from the input of tannery wastewater due to the preferential removal of Cr,(III). In the filtered water in Morocco a large fraction of Cr occurred in the HMWC fraction (50,70,%) at the two most contaminated sites, while the LMWC and TD forms prevailed at the non-contaminated sites in the Sebou River. At a very high concentration, in the water in the proximity of tanneries (well above the theoretical saturation level) Cr precipitated as polynuclear Cr-hydroxide. In Dunajec-Czorsztyn, the partition of Cr,(III) was approximately equal between the HMWC, LMWC and TD fractions, in contrast to Cr,(VI) which occurred almost exclusively in the TD fraction. In both systems, Cr,(III) was rapidly removed from the water to the sediments. The confluence of the Sebou with the Fez and the Czorsztyn reservoir trapped efficiently Cr,(III) preventing its spreading over long distances. Cr,(VI) showed conservative behavior and bypassed the Czorsztyn Reservoir. This study provides a first set of data on the partitioning of Cr,(III) and Cr,(VI) between the particulate, the colloidal and truly dissolved fractions in fluvial systems contaminated with tannery effluents. It also suggests that, in these systems, truly dissolved Cr,(III) can be adequately modeled from the total filterable concentrations. [source] Cathepsin X cleaves the ,2 cytoplasmic tail of LFA-1 inducing the intermediate affinity form of LFA-1 and ,-actinin-1 bindingEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2009Zala Jevnikar Abstract The motility of T cells depends on the dynamic spatial regulation of integrin-mediated adhesion and de-adhesion. Cathepsin X, a cysteine protease, has been shown to regulate T-cell migration by interaction with lymphocyte function associated antigen-1 (LFA-1). LFA-1 adhesion to the ICAM-1 is controlled by the association of actin-binding proteins with the cytoplasmic tail of the ,2 chain of LFA-1. Cleavage by cathepsin X of the amino acid residues S769, E768 and A767 from the C-terminal of the ,2 cytoplasmic tail of LFA-1 is shown to promote binding of the actin-binding protein ,-actinin-1. Furthermore, cathepsin X overexpression reduced LFA-1 clustering and induced an intermediate affinity LFA-1 conformation that is known to associate with ,-actinin-1. Increased levels of intermediate affinity LFA-1 resulted in augmented cell spreading due to reduced attachment of T cells to the ICAM-1-coated surface. Gradual cleavage of LFA-1 by cathepsin X enables the transition between intermediate and high affinity LFA-1, an event that is crucial for effective T-cell migration. [source] Expression of PI(4,5)P2 -binding proteins lowers the PI(4,5)P2 level and inhibits Fc,RIIA-mediated cell spreading and phagocytosisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2008Ewelina Szyma Abstract We found that Fc,RII-mediated cell spreading and phagocytosis were correlated with an increase of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] level in cells. During the spreading, a long-lasting elevation of PI(4,5)P2 and concomitant actin polymerization occurred. Filopodia and lamellae of spreading cells were enriched in phosphatidylinositol 4-phosphate 5-kinase I, (PIP5-kinase I,) that colocalized with PI(4,5)P2 and actin filaments. Both spreading and phagocytosis were inhibited by expression of the C374,440 fragment of PIP5-kinase I, or the pleckstrin homology domain of phospholipase C,1 (PLC,1 -PH), two probes binding PI(4,5)P2. These probes reduced the amount of PI(4,5)P2 in the cells, evoked reorganization of the actin cytoskeleton and abolished PI(4,5)P2 elevation during phagocytosis. Simultaneously, PLC,1 -PH-GFP reduced the amount of PIP5-kinase I, associated with the plasma membrane. In vitro studies demonstrated that PIP5-kinase I,-GST bound PI(4,5)P2, phosphatidylinositol 4-monophosphate, and less efficiently, phosphatidic acid. The data suggest that the PLC,1 -PH domain, and possibly also the C374,440 fragment, when expressed in cells, can compete with endogenous PIP5-kinase I, for PI(4,5)P2 binding in the plasma membrane leading eventually to PI(4,5)P2 depletion. [source] Positively Charged Material Surfaces Generated by Plasma Polymerized Allylamine Enhance Vinculin Mobility in Vital Human Osteoblastss,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Henrike Rebl Abstract Several studies suggest that the modification of an implant surface by chemical means plays an important role in bone tissue engineering. Previously we have shown that osteoblast cell adhesion and spreading can strongly be increased by a positively charged surface. Cell adhesion and migration are two vital processes that are completely dependent on coordinated formation of focal adhesions. Changes in the organization of the actin cytoskeleton and the focal adhesions are essential for numerous cellular processes including cell motility and tissue morphogenesis. We examined the mobility of the cytoskeletally associated protein vinculin on functionalized surfaces using plasma polymerized allylamine (PPAAm), a homogenous plasma polymer layer with randomly distributed amino groups. In living, GFP,vinculin transfected osteoblastic cells we determined a significant increase in vinculin mobility and vinculin contact length on PPAAm compared to collagen I coated surfaces during the initial adhesion phase. We suggest that positive charges control the cell physiology which seems to be dominant over the integrin receptor binding to collagen I. The results emphasize the role of the surface charge for the design of artificial scaffolds in bone repair. [source] Nigrostriatal lesion induces D2-modulated phase-locked activity in the basal ganglia of ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2007Camila L. Zold Abstract There is a debate as to what modifications of neuronal activity underlie the clinical manifestations of Parkinson's disease and the efficacy of antiparkinsonian pharmacotherapy. Previous studies suggest that release of GABAergic striatopallidal neurons from D2 receptor-mediated inhibition allows spreading of cortical rhythms to the globus pallidus (GP) in rats with 6-hydroxydopamine-induced nigrostriatal lesions. Here this abnormal spreading was thoroughly investigated. In control urethane-anaesthetized rats most GP neurons were excited during the active part of cortical slow waves (,direct-phase' neurons). Two neuronal populations having opposite phase relationships with cortical and striatal activity coexisted in the GP of 6-hydroxydopamine-lesioned rats. ,Inverse-phase' GP units exhibited reduced firing coupled to striatal activation during slow waves, suggesting that this GP oscillation was driven by striatopallidal hyperactivity. Half of the pallidonigral neurons identified by antidromic stimulation exhibited inverse-phase activity. Therefore, spreading of inverse-phase oscillations through pallidonigral axons might contribute to the abnormal direct-phase cortical entrainment of basal ganglia output described previously. Systemic administration of the D2 agonist quinpirole to 6-hydroxydopamine-lesioned rats reduced GP inverse-phase coupling with slow waves, and this effect was reversed by the D2 antagonist eticlopride. Because striatopallidal hyperactivity was only slightly reduced by quinpirole, other mechanisms might have contributed to the effect of quinpirole on GP oscillations. These results suggest that antiparkinsonian efficacy may rely on other actions of D2 agonists on basal ganglia activity. However, abnormal slow rhythms may promote enduring changes in functional connectivity along the striatopallidal axis, contributing to D2 agonist-resistant clinical signs of parkinsonism. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||